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Showing 100 Latest Publications
TitleDate Created
Targeting Notch Signaling and Autophagy Increases Cytotoxicity in Glioblastoma Neurospheres.Friday, November 27, 2015
Natsumeda M, Maitani K, Liu Y, Miyahara H, Kaur H, Chu Q, Zhang H, Kahlert U, Eberhart CG,
Brain pathology (Zurich, Switzerland). 27-Nov-2015
Glioblastomas are highly aggressive tumors that contain treatment resistant stem-like cells. Therapies targeting developmental pathways such as Notch eliminate many neoplastic glioma cells, including those with stem cell features, but their efficacy can be limited by various mechanisms. One potential avenue for chemotherapeutic resistance is the induction of autophagy, but little is known how it might modulate the response to Notch inhibitors. We used the γ-secretase inhibitor (GSI) MRK003 to block Notch pathway activity in glioblastoma neurospheres and assessed effects on autophagy. A dramatic, several fold increase of LC3B-II/LC3B-I autophagy marker was noted on western blots, along with the emergence of punctate LC3B immunostaining in cultured cells. By combining the late stage autophagy inhibitor chloroquine (CQ) with MRK003, a significant induction in apoptosis and reduction in growth was noted as compared to Notch inhibition alone. A similar beneficial effect on inhibition of clonogenicity in soft agar was seen using the combination treatment. These results demonstrate that pharmacological Notch blockade can induce protective autophagy in glioma neurospheres, resulting in chemoresistance, which can be abrogated by combination treatment with autophagy inhibitors. This article is protected by copyright. All rights reserved.
Entropy, Ergodicity, and Stem Cell Multipotency.Friday, November 27, 2015
Ridden SJ, Chang HH, Zygalakis KC, MacArthur BD,
Physical review letters. 13-Nov-2015
Populations of mammalian stem cells commonly exhibit considerable cell-cell variability. However, the functional role of this diversity is unclear. Here, we analyze expression fluctuations of the stem cell surface marker Sca1 in mouse hematopoietic progenitor cells using a simple stochastic model and find that the observed dynamics naturally lie close to a critical state, thereby producing a diverse population that is able to respond rapidly to environmental changes. We propose an information-theoretic interpretation of these results that views cellular multipotency as an instance of maximum entropy statistical inference.
The CUL4-DDB1 ubiquitin ligase complex controls adult and embryonic stem cell differentiation and homeostasis.Friday, November 27, 2015
Gao J, Buckley SM, Cimmino L, Guillamot M, Strikoudis A, Cang Y, Goff SP, Aifantis I,
eLife. 27-Nov-2015
Little is known on post-transcriptional regulation of stem cell maintenance and differentiation. Here we characterize the role of Ddb1, a component of the CUL4-DDB1 ligase complex. Ddb1 is highly expressed in hematopoietic stem cells and its deletion leads to abrogation of hematopoiesis, targeting specifically transiently amplifying progenitor subsets. Ddb1 deletion in non-dividing lymphocytes had no discernible phenotypes. Ddb1 silencing activated the p53 pathway and lead to apoptosis. The abrogation of hematopoietic progenitor cells can be partially rescued by simultaneous deletion of p53. Interestingly, depletion of DDB1 in embryonic stem cell (ESC) does not affect survival or cell cycle progression but leads to loss of pluripotency, suggesting distinct roles of DDB1 in adult and embryonic stem cells. Mass-spectrometry revealed distinct interactions between DDB1 and DCAFs, the substrate-recognizing components of the CUL4 complex between cell types. Our studies identify the CUL4-DDB1 complex as a novel post-translational regulator of stem maintenance and differentiation.
Renal Contrast Enhanced Sonography Findings in a Model of Acute Cellular Allograft Rejection.Friday, November 27, 2015
Grabner A, Kentrup D, Pawelski H, Mühlmeister M, Biermann C, Heitplatz B, Van Marck V, Bettinger T, Pavenstädt H, Schlatter E, Stypmann J, Tiemann K, Reuter S,
American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. 27-Nov-2015
Non-invasive methods to diagnose and differentiate acute cellular rejection from acute tubular necrosis or acute calcineurin inhibitor toxicity are still missing. Since T-lymphocytes play a decisive role already in early states of rejection, we investigated the suitability and feasibility of antibody-mediated contrast-enhanced ultrasound using microbubbles targeted to CD3, CD4 or CD8 positive T-cells in different models of renal disease. In an established rat renal transplantation model CD3-mediated ultrasound allows the detection of acute rejection as early as on postoperative day 2. Ultrasound signal intensities increased with the severity of inflammation. Furthermore, an early response to therapy could be monitored using contrast-enhanced sonography. Notably, acute tubular necrosis occurring after ischemia/reperfusion injury as well as acute calcineurin inhibitor toxicity could easily be differentiated. Finally, the quantified ultrasound signal correlated significantly with the number of infiltrating T-cells obtained by histology and with CD3 mRNA levels, as well as with chemokine CXCL9, CXCL11 and CCL19 mRNA, but not with KIM-1 mRNA expression, thereby representing the severity of graft inflammation but not the degree of kidney injury. In summary, we demonstrate that antibody-mediated contrast-enhanced ultrasound targeting T-lymphocytes could be a promising tool for an easy and reproducible assessment of acute rejection after renal transplantation. This article is protected by copyright. All rights reserved.
Successful treatment of cytomegalovirus enteritis after unrelated allogeneic stem cell transplantation by the infusion of ex vivo-expanded CD4(+) lymphocytes derived from the recipient's peripheral blood donor cells.Friday, November 27, 2015
Muto T, Takeda Y, Tsukamoto S, Sakai S, Mimura N, Ohwada C, Takeuchi M, Sakaida E, Ota S, Iseki T, Shimizu N, Morio T, Nakaseko C,
Transplant infectious disease : an official journal of the Transplantation Society. 27-Nov-2015
Adoptive immunotherapies have been developed for antiviral agent-refractory cytomegalovirus (CMV) disease after stem cell transplantation (SCT). However, the application of such strategies is limited, particularly in terms of need for donor cooperation regarding blood sampling and inaccessibility in the setting of cord blood transplantation. Herein, we describe the first successful treatment of antiviral agent-refractory CMV enteritis after allogeneic SCT by the infusion of ex vivo-expanded donor-derived CD4(+) lymphocytes obtained from the recipient's peripheral blood. This article is protected by copyright. All rights reserved.
Rapid generation of sub-type, region-specific neurons and neural networks from human pluripotent stem cell-derived neurospheres.Friday, November 27, 2015
Begum AN, Guoynes C, Cho J, Hao J, Lutfy K, Hong Y,
Stem cell research. 24-Oct-2015
Stem cell-based neuronal differentiation has provided a unique opportunity for disease modeling and regenerative medicine. Neurospheres are the most commonly used neuroprogenitors for neuronal differentiation, but they often clump in culture, which has always represented a challenge for neurodifferentiation. In this study, we report a novel method and defined culture conditions for generating sub-type or region-specific neurons from human embryonic and induced pluripotent stem cells derived neurosphere without any genetic manipulation. Round and bright-edged neurospheres were generated in a supplemented knockout serum replacement medium (SKSRM) with 10% CO2, which doubled the expression of the NESTIN, PAX6 and FOXG1 genes compared with those cultured with 5% CO2. Furthermore, an additional step (AdSTEP) was introduced to fragment the neurospheres and facilitate the formation of a neuroepithelial-type monolayer that we termed the "neurosphederm". The large neural tube-type rosette (NTTR) structure formed from the neurosphederm, and the NTTR expressed higher levels of the PAX6, SOX2 and NESTIN genes compared with the neuroectoderm-derived neuroprogenitors. Different layers of cortical, pyramidal, GABAergic, glutamatergic, cholinergic neurons appeared within 27days using the neurosphederm, which is a shorter period than in traditional neurodifferentiation-protocols (42-60days). With additional supplements and timeline dopaminergic and Purkinje neurons were also generated in culture too. Furthermore, our in vivo results indicated that the fragmented neurospheres facilitated significantly better neurogenesis in severe combined immunodeficiency (SCID) mouse brains compared with the non-fragmented neurospheres. Therefore, this neurosphere-based neurodifferentiation protocol is a valuable tool for studies of neurodifferentiation, neuronal transplantation and high throughput screening assays.
Evidence of increased brain amyloid in severe TBI survivors at 1, 12, and 24 months after injury: report of 2 cases.Friday, November 27, 2015
Gatson JW, Stebbins C, Mathews D, Harris TS, Madden C, Batjer H, Diaz-Arrastia R, Minei JP,
Journal of neurosurgery. 27-Nov-2015
Traumatic brain injury (TBI) is a major risk factor for Alzheimer's disease. With respect to amyloid deposition, there are no published serial data regarding the deposition rate of amyloid throughout the brain after TBI. The authors conducted serial (18)F-AV-45 (florbetapir F18) positron emission tomography (PET) imaging in 2 patients with severe TBI at 1, 12, and 24 months after injury. A total of 12 brain regions were surveyed for changes in amyloid levels. Case 1 involved a 50-year-old man who experienced a severe TBI. Compared with the 1-month time point, of the 12 brain regions that were surveyed, a decrease in amyloid (as indicated by standard uptake value ratios) was only observed in the hippocampus (-16%, left; -12%, right) and caudate nucleus (-18%, left; -18%, right), suggesting that initial amyloid accumulation in the brain was cleared between time points 1 and 12 months after injury. Compared to the scan at 1 year, a greater increase in amyloid (+15%) was observed in the right hippocampus at the 24-month time point. The patient in Case 2 was a 37-year-old man who suffered severe trauma to the head and a subsequent stroke; he had poor cognitive/functional outcomes and underwent 1.5 years of rehabilitation. Due to a large infarct area on the injured side of the brain (right side), the authors focused primarily on brain regions affected within the left hemisphere. Compared with the 1-month scan, they only found an increase in brain amyloid within the left anterior putamen (+11%) at 12 months after injury. In contrast, decreased amyloid burden was detected in the left caudate nucleus (-48%), occipital cortex (-21%), and precuneus (-19%) brain regions at the 12-month time point, which is indicative of early accumulation and subsequent clearance. In comparison with 12-month values, more clearance was observed, since a reduction in amyloid was found at 24 months after trauma within the left anterior putamen (-12%) and occipital cortex (-15%). Also, by 24 months, most of the amyloid had been cleared and the patient demonstrated improved results on the Rivermead symptom questionnaire, Glasgow Outcome Scale-Extended, and Disability Rating Scale. With respect to APOE status, the patient in Case 1 had two ε3 alleles and the patient in Case 2 had one ε2 and one ε3 allele. In comparison to the findings of the initial scan at 1 month after TBI, by 12 and 24 months after injury amyloid was cleared in some brain regions and increased in others. Serial imaging conducted here suggests that florbetapir F18 PET imaging may be useful in monitoring amyloid dynamics within specific brain regions following severe TBI and may be predictive of cognitive deficits.
Aviremia 10 Years Postdiscontinuation of Antiretroviral Therapy Initiated During Primary Human Immunodeficiency Virus-1 Infection and Association With Gag-Specific T-Cell Responses.Friday, November 27, 2015
Kinloch-de Loes S, Dorrell L, Yang H, Hardy GA, Yerly S, Cellerai C, Vandekerckhove L, De Spielgelaere W, Malatinkova E, Wee Lee Koh W, Johnson MA,
Open forum infectious diseases. Dec-2015
Combination antiretroviral therapy during primary human immunodeficiency virus-1 infection may enable long-term drug-free virological control in rare individuals. We describe a female who maintained aviremia and a normal CD4(+)/CD8(+) T cell ratio for 10 years after stopping therapy, despite a persistent viral reservoir. Cellular immune responses may have contributed to this outcome.
Autophagy Inhibition to Increase Radiosensitization in Breast Cancer.Friday, November 27, 2015
Liang DH, El-Zein R, Dave B,
Journal of nuclear medicine & radiation therapy. 23-11-2015
Currently, many breast cancer patients with localized breast cancer undergo breast-conserving therapy, consisting of local excision followed by radiation therapy. Following radiation therapy, breast cancer cells are noted to undergo induction of autophagy, development of radioresistance, and enrichment of breast cancer stem cell subpopulations. It is hypothesized that inhibition of the cytoprotective autophagy that arises following radiation therapy increases radiosensitivity and confers longer relapse-free survival by eliminating tumor-initiating breast cancer stem cells. Therefore, we reviewed the controversial role of autophagy in breast cancer tumorigenesis and progression, autophagy induction by radiotherapy, and utilization of autophagy inhibitors to increase radiosensitivity of breast cancer and to target radioresistant breast cancer stem cells.
Pharmacokinetics and safety of intravesicular cidofovir in allogeneic HSCT recipients.Friday, November 27, 2015
Aitken SL, Zhou J, Ghantoji SS, Kontoyiannis DP, Jones RB, Tam VH, Chemaly RF,
The Journal of antimicrobial chemotherapy. 26-Nov-2015
Intravesicular administration of cidofovir resulted in highly variable systemic exposures. The safety and efficacy of intravesicular cidofovir should be further evaluated before routine use.
Phase 3 pharmacokinetics and safety study of a posaconazole tablet formulation in patients at risk for invasive fungal disease.Friday, November 27, 2015
Cornely OA, Duarte RF, Haider S, Chandrasekar P, Helfgott D, Jiménez JL, Candoni A, Raad I, Laverdiere M, Langston A, Kartsonis N, Van Iersel M, Connelly N, Waskin H,
The Journal of antimicrobial chemotherapy. 26-Nov-2015
In patients at high risk for invasive fungal disease, 300 mg posaconazole (as tablets) once daily was well tolerated and demonstrated a safety profile similar to that reported for posaconazole oral suspension: most patients (99%) achieved steady-state pCavg exposures >500 ng/mL and only one patient (<1%) had a pCavg <500 ng/mL.
Mechanical influence of tissue culture plates and extracellular matrix on mesenchymal stem cell behavior: A topical review.Friday, November 27, 2015
Tatullo M, Marrelli M, Falisi G, Rastelli C, Palmieri F, Gargari M, Zavan B, Paduano F, Benagiano V,
International journal of immunopathology and pharmacology. 26-Nov-2015
Tissue engineering applications need a continuous development of new biomaterials able to generate an ideal cell-extracellular matrix interaction. The stem cell fate is regulated by several factors, such as growth factors or transcription factors. The most recent literature has reported several publications able to demonstrate that environmental factors also contribute to the regulation of stem cell behavior, leading to the opinion that the environment plays the major role in the cell differentiation.The interaction between mesenchymal stem cells (MSCs) and extracellular environment has been widely described, and it has a crucial role in regulating the cell phenotype. In our laboratory (Tecnologica Research Institute, Crotone, Italy), we have recently studied how several physical factors influence the distribution and the morphology of MSCs isolated from dental pulp, and how they are able to regulate stem cell differentiation. Mechanical and geometrical factors are only a small part of the environmental factors able to influence stem cell behavior, however, this influence should be properly known: in fact, this assumption must be clearly considered during those studies involving MSCs; furthermore, these interactions should be considered as an important bias that involves an high number of studies on the MSCs, since in worldwide laboratories the scientists mostly use tissue culture plates for their experiments.
Osteogenic protein 1 does not stimulate a regenerative effect in cultured human degenerated nucleus pulposus tissue.Friday, November 27, 2015
van Dijk BG, Potier E, van Dijk M, Creemers LB, Ito K,
Journal of tissue engineering and regenerative medicine. 27-Nov-2015
Low back pain is a major cause of disability and is heavily associated with intervertebral disc degeneration. Osteogenic protein 1 (OP-1) is a growth factor that has shown potential to regenerate the intervertebral disc in human cells and animal models. However, high doses are required, presumably due to clearance from the tissue; controlled release may be a solution to this problem. In this study, we developed a preclinical, pathophysiological human tissue explant culture model of degenerated nucleus pulposus (NP). The NP explants were cultured for 28 days and injected with 100 µg OP-1 as a bolus, or with sustained-release biodegradable microspheres loaded with 16 or 1.6 µg OP-1. After culture, the tissue explants were analysed for biochemical content [water, sulphated glycosaminoglycans (GAGs), hydroxyproline and DNA], histology, cell viability and gene expression (disc matrix anabolic and catabolic markers). Untreated degenerated NP explants lost some of their GAG content when cultured for 4 weeks, but maintained other tissue constituents. Gene expression levels were close to native values. A bolus injection of OP-1 partially restored GAG content to the native level in half of the donors, while the sustained release of OP-1 did not affect the NP explants. No effect of treatment was observed on anabolic or catabolic gene expression at day 28. These results demonstrated that the regenerative potential of OP-1 is donor dependent, and only at very high doses. This questions the clinical use of OP-1 as a regenerative agent, as these high doses may increase the incidence of complications. Copyright © 2015 John Wiley & Sons, Ltd.
Can Dicoumarol Be Used As A Gonad-Safe Anti-Cancer Agent: An In Vitro And In Vivo Experimental Study.Friday, November 27, 2015
Aras D, Cinar O, Cakar Z, Ozkavukcu S, Can A,
Molecular human reproduction. 26-Nov-2015
This work includes data from dissertation thesis entitled "Effects of dicoumarol on mitotic and meiotic cells as an anticancer agent" by DA, 2014 and was partly supported by the National Scientific and Technological Research Council (SBAG-109S415) to AC, OC and SO. The authors confirm that this article content presents no conflicts of interest.
Octacalcium phosphate collagen composite facilitates bone regeneration of large mandibular bone defect in humans.Friday, November 27, 2015
Kawai T, Suzuki O, Matsui K, Tanuma Y, Takahashi T, Kamakura S,
Journal of tissue engineering and regenerative medicine. 27-Nov-2015
Recently it was reported that the implantation of octacalcium phosphate (OCP) and collagen composite (OCP-collagen) was effective at promoting bone healing in small bone defects after cystectomy in humans. In addition, OCP-collagen promoted bone regeneration in a critical-sized bone defect of a rodent or canine model. In this study, OCP-collagen was implanted into a human mandibular bone defect with a longer axis of approximately 40 mm, which was diagnosed as a residual cyst with apical periodontitis. The amount of OCP-collagen implanted was about five times greater than the amounts implanted in previous clinical cases. Postoperative wound healing was satisfactory and no infection or allergic reactions occurred. The OCP-collagen-treated lesion was gradually filled with radio-opaque figures, and the alveolar region occupied the whole of the bone defect 12 months after implantation. This study suggests that OCP-collagen could be a useful bone substitute material for repairing large bone defects in humans that might not heal spontaneously. Copyright © 2015 John Wiley & Sons, Ltd.
Conditioned media from hypoxic-cultured human dental pulp cells promotes bone healing during distraction osteogenesis.Friday, November 27, 2015
Fujio M, Xing Z, Sharabi N, Xue Y, Yamamoto A, Hibi H, Ueda M, Fristad I, Mustafa K,
Journal of tissue engineering and regenerative medicine. 27-Nov-2015
Distraction osteogenesis (DO) is a surgical procedure used to correct various skeletal disorders. Improving the technique by reducing the healing time would be of clinical relevance. The aim of this study was to determine the angiogenic and regenerative potential of conditioned media (CMs) collected from human dental pulp cells (hDPCs) grown under different culture conditions. CM collected from cells under hypoxia was used to improve bone healing and the DO procedure in vivo. The angiogenic potentials of CMs collected from hDPCs grown under normoxic (-Nor) and hypoxic (-Hyp) conditions were evaluated by quantitative PCR (VEGF-A, angiopoietin-1, angiopoietin-2, interleukin-6 (IL-6) and CXCL12), ELISA assays (VEGF-A, Ang-2), tube-formation and wound-healing assays, using human umbilical vein endothelial cells. The results demonstrated that hypoxic CM had significantly higher angiogenic potential than normoxic CM. Human fetal osteoblasts (hFOBs) were exposed to CM, followed by alizarin red staining, to assess the osteogenic potential. It was found that CM did not enhance the mineralization capacity of hFOBs. DO was performed in the tibiae of 30 mice, followed by a local injection of 20 µl CM (CM-Nor and CM-Hyp groups) or serum-free DMEM (control group) into the distraction zone every second day. The mice were sacrificed at days 13 and 27. The CM-Hyp treatment revealed a higher X-ray density than the control group (p < 0.05). Our study suggests that the angiogenic effect promoted by hypoxic culture conditions is dependent on VEGF-A and Ang-2 released from hDPCs. Furthermore, CM-Hyp treatment may thus improve the DO procedure, accelerating bone healing. © 2015 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd.
Cancer stem cell markers: premises and prospects.Friday, November 27, 2015
Murar M, Vaidya A,
Biomarkers in medicine. Dec-2015
Over the last decade, compelling evidence has shown that cancer stem cells (CSCs) exist in a variety of malignancies. The conventional method for anticancer therapy involves targeting only the proliferating mitotic cells, sparing the slow-cycling cells that eventually evade chemotherapy and become a source of post therapy relapses. With the increasing awareness of CSCs supported by sophisticated experimental evidence, therapeutic strategies today are aimed at selectively identifying and targeting CSCs using biomarkers. The ability to identify CSCs allows targeted elimination of these cancer-initiating cells. Herein, we discuss CSC markers in the context of different types of cancers, their significance in selectively identifying CSCs and the therapeutic implications of using these biomarkers to prevent invasion and metastasis of cancer.
Evaluation of nephrotoxic effects of aristolochic acid on zebrafish (Danio rerio) larvae.Friday, November 27, 2015
Wang X, Liu KC, Sun GJ, Han LW, Wang RC, Peng WB, Sun C, Hsiao CD, Zhang Y, Hou HR,
Human & experimental toxicology. 26-Nov-2015
To analyze the toxic effects of aristolochic acid (AA) on developed kidneys in zebrafish larvae, zebrafish at 3 days postfertilization were treated with various concentrations of AA for 24 h before the status of kidney injury was investigated from several points of view. It was found that 21% of the larvae treated with 10 µmoL/L AA exhibited evident periocular edema. When the concentrations of AA were increased to 20 and 40 µmoL/L, defect in the cardiovascular system characterized by slow heart beat and blood flow was seen coupled with periocular edema. Creatinine in the whole larval tissue determined by liquid chromatography-mass spectrometry/mass spectrometry exhibited dramatic increase in the treated groups in a dose-dependent manner within a certain range of doses. Several evident protein bands were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in supernatant of the treated larvae, indicating leakage of glomerular filtration barrier. Results of quantitative polymerase chain reaction show that the messenger RNA expression of nephrin in the 20 and 40 µmoL/L AA-treated groups decreased to 0.58 ± 0.062 and 0.37 ± 0.075-folds of the control, respectively. Kidney damage was further confirmed by the histological changes in paraffin sections of treated larvae, for example, cystic glomeruli and disorganized epithelia cells of pronephric tubules. Our results revealed that AA exerted toxic effects on developed kidney of zebrafish larvae in a dose-dependent manner and podocyte dysfunction may be involved in the kidney injury and proteinuria.
Shockwave as Biological Therapeutic Tool: from mechanical stimulation to recovery and healing, through Mechanotransduction.Friday, November 27, 2015
Cristina d'Agostino M, Craig K, Tibalt E, Respizzi S,
International journal of surgery (London, England). 20-Nov-2015
⁃Extracorporeal Shock Wave Therapy (ESWT) is a form of "mechanotherapy", that, from its original applications as urological lithotripsy, gained the field of musculo-skeletal diseases as Orthotripsy (mainly tendinopaties and bone regenerative disorders) and Regenerative Medicine as well. ⁃The mechanisms of action of Shock Waves (SW), when applied in non-urological indications, are not related to the direct mechanical effect, but to the different pathways of biological reactions, that derive from that acoustic stimulations, through "mechano-transduction". So, the "mechanical model" of urological lithotripsy has been substituted by a "biological model", also supported by current knowledge in "mechanobiology", the emerging multidisciplinary field of science that investigates how physical forces and changes in cell/tissue mechanics can influence the tissue development, physiology and diseases. ⁃Although some details are still under study, it is known that SW are able to relief pain, as well to positively regulate inflammation (probably as immunomodulator), to induce neoangiogenesis and stem cells activities, thus improving tissue regeneration and healing. ⁃ESWT can be nowadays considered an effective, safe, versatile, repeatable, noninvasive therapy for the treatment of many musculo-skeletal diseases, and for some pathological conditions where regenerative effects are desirable, especially when some other noninvasive/conservative therapies have failed. ⁃Moreover, based on the current knowledge in SW mechanobiology, it seems possible to foresee new interesting and promising applications in the fields of Regenerative Medicine, tissue engineering and cell therapies.
Use of nanoscale mechanical stimulation for control and manipulation of cell behaviour.Friday, November 27, 2015
Childs PG, Boyle CA, Pemberton GD, Nikukar H, Curtis AS, Dalby MJ, Reid S,
Acta biomaterialia. 20-Nov-2015
The ability to control cell behaviour, cell fate and simulate reliable tissue models in vitro remains a significant challenge yet is crucial for various applications of high throughput screening e.g. drug discovery. Mechanotransduction (the ability of cells to convert mechanical forces in their environment to biochemical signaling) represents an alternative mechanism to attain this control with such studies developing techniques to reproducibly control the mechanical environment in techniques which have potential to be scaled. In this review, the use of techniques such as finite element modelling and precision interferometric measurement are examined to provide context for a novel technique based on nanoscale vibration, also known as "nanokicking". Studies have shown this stimulus to alter cellular responses in both endothelial and mesenchymal stem cells (MSCs), particularly in increased proliferation rate and induced osteogenesis respectively. Endothelial cell lines were exposed to nanoscale vibration amplitudes across a frequency range of 1 Hz to 100 Hz, and MSCs primarily at 1 kHz. This technique provides significant potential benefits over existing technologies, as cellular responses can be initiated without the use of expensive engineering techniques and/or chemical induction factors. Due to the reproducible and scalable nature of the apparatus it is conceivable that nanokicking could be used for controlling cell behaviour within a wide array of high throughput procedures in the research environment, within drug discovery, and for clinical/therapeutic applications.
Inhibition of COX1/2 alters the host response and reduces ECM scaffold mediated constructive tissue remodeling in a rodent model of skeletal muscle injury.Friday, November 27, 2015
Dearth CL, Slivka PF, Stewart SA, Keane TJ, Tay JK, Londono R, Goh Q, Pizza FX, Badylak SF,
Acta biomaterialia. 20-Nov-2015
Extracellular matrix (ECM) has been used as a biologic scaffold material to both reinforce the surgical repair of soft tissue and serve as an inductive template to promote a constructive tissue remodeling response. Success of such an approach is dependent on macrophage-mediated degradation and remodeling of the biologic scaffold. Macrophage phenotype during these processes is a predictive factor of the eventual remodeling outcome. ECM scaffolds have been shown to promote an anti-inflammatory or M2-like macrophage phenotype in vitro that includes secretion of downstream products of cycolooxygenases 1 and 2 (COX1/2). The present study investigated the effect of a common COX1/2 inhibitor (Aspirin) on macrophage phenotype and tissue remodeling in a rodent model of ECM scaffold treated skeletal muscle injury. Inhibition of COX1/2 reduced the constructive remodeling response by hindering myogenesis and collagen deposition in the defect area. The inhibited response was correlated with a reduction in M2-like macrophages in the defect area. The effects of Aspirin on macrophage phenotype were corroborated using an established in vitro macrophage model which showed a reduction in both ECM induced prostaglandin secretion and expression of a marker of M2-like macrophages (CD206). These results raise questions regarding the common peri-surgical administration of COX1/2 inhibitors when biologic scaffold materials are used to facilitate muscle repair/regeneration.
Preservation of Human Limbal Epithelial Progenitor Cells on Carbodiimide Cross-linked Amniotic Membrane via Integrin-Linked Kinase-mediated Wnt Activation.Friday, November 27, 2015
Ma DH, Chen HC, Ma KS, Lai JY, Yang U, Yeh LK, Hsueh YJ, Chu WK, Lai CH, Chen JK,
Acta biomaterialia. 20-Nov-2015
The Wnt pathway is a major signaling pathway that regulates corneal epithelial stem cells. However, little is known about how the ultrastructure of the limbal epithelial basement membrane (EBM) affects Wnt activity. Due to its enhanced matrix stability, the cross-linked amniotic membrane (AM) has gained increasing interest in the field of regenerative medicine. For the first time, we used EDC/NHS cross-linked denuded AM (CLDAM) as a simulated EBM substrate to investigate this mechanism. Human limbal epithelial (HLE) cells were cultured on dishes (HLE/dish), denuded AM (HLE/DAM) or CLDAM (HLE/CLDAM). Compared with HLE/dish or HLE/DAM cultures, HLE/CLDAM cultures showed greater BrdU retention and colony formation efficiency and expressed higher levels of p63, ABCG2, integrin β1, and integrin-linked kinase (ILK). Nuclear β-catenin and TCF-4 levels were higher in HLE/CLDAM cultures compared with HLE cells cultured on collagen IV, laminin, Matrigel, or DAM. Silencing of ILK in HLE/CLDAM cultures resulted in decreased levels of nuclear β-catenin, TCF-4 and deltaNp63α, whereas cytokeratin 12 expression increased. Over-expression of ILK in HLE/dish cultures had the opposite effects. Accordingly, we proposed that the CLDAM matrix, with its higher rigidity and rougher ultrastructure, better preserved HLE progenitor cells in vitro, possibly by activating integrin β1/ILK, which indirectly activated Wnt/β-catenin and subsequently deltaNp63α. Crosstalk between the integrin β1/ILK and Wnt/β-catenin pathways appears to play a crucial role in limbal progenitor cell survival on EBM.
iPSC-derived human cardiac progenitor cells improve ventricular remodelling via angiogenesis and interstitial networking of infarcted myocardium.Friday, November 27, 2015
Ja KM, Miao Q, Zhen Tee NG, Lim SY, Nandihalli M, J A Ramachandra C, Mehta A, Shim W,
Journal of cellular and molecular medicine. 27-Nov-2015
We investigate the effects of myocardial transplantation of human induced pluripotent stem cell (iPSC)-derived progenitors and cardiomyocytes into acutely infarcted myocardium in severe combined immune deficiency mice. A total of 2 × 10(5) progenitors, cardiomyocytes or cell-free saline were injected into peri-infarcted anterior free wall. Sham-operated animals received no injection. Myocardial function was assessed at 2-week and 4-week post-infarction by using echocardiography and pressure-volume catheterization. Early myocardial remodelling was observed at 2-week with echocardiography derived stroke volume (SV) in saline (20.45 ± 7.36 μl, P < 0.05) and cardiomyocyte (19.52 ± 3.97 μl, P < 0.05) groups, but not in progenitor group (25.65 ± 3.61 μl), significantly deteriorated as compared to sham control group (28.41 ± 4.41 μl). Consistently, pressure-volume haemodynamic measurements showed worsening chamber dilation in saline (EDV: 23.24 ± 5.01 μl, P < 0.05; ESV: 17.08 ± 5.82 μl, P < 0.05) and cardiomyocyte (EDV: 26.45 ± 5.69 μl, P < 0.05; ESV: 18.03 ± 6.58 μl, P < 0.05) groups by 4-week post-infarction as compared to control (EDV: 15.26 ± 2.96 μl; ESV: 8.41 ± 2.94 μl). In contrast, cardiac progenitors (EDV: 20.09 ± 7.76 μl; ESV: 13.98 ± 6.74 μl) persistently protected chamber geometry against negative cardiac remodelling. Similarly, as compared to sham control (54.64 ± 11.37%), LV ejection fraction was preserved in progenitor group from 2-(38.68 ± 7.34%) to 4-week (39.56 ± 13.26%) while cardiomyocyte (36.52 ± 11.39%, P < 0.05) and saline (35.34 ± 11.86%, P < 0.05) groups deteriorated early at 2-week. Improvements of myocardial function in the progenitor group corresponded to increased vascularization (16.12 ± 1.49/mm(2) to 25.48 ± 2.08/mm(2) myocardial tissue, P < 0.05) and coincided with augmented networking of cardiac telocytes in the interstitial space of infarcted zone.
Adult Stem Cells in Aging, Diseases and Cancer.Friday, November 27, 2015
Seth T,
The National medical journal of India. 27-11-2015
Approaches to Improving Cardiac Structure and Function During and After an Acute Myocardial Infarction: Acute and Chronic Phases.Friday, November 27, 2015
Kloner RA, Dai W, Hale SL, Shi J,
Journal of cardiovascular pharmacology and therapeutics. 25-Nov-2015
While progress has been made in improving survival following myocardial infarction, this injury remains a major source of mortality and morbidity despite modern reperfusion therapy. While one approach has been to develop therapies to reduce lethal myocardial cell reperfusion injury, this concept has not translated to the clinics, and several recent negative clinical trials raise the question of whether reperfusion injury is important in humans undergoing reperfusion for acute ST segment elevation myocardial infarction. Therapy aimed at reducing myocardial cell death while the myocytes are still ischemic is more likely to further reduce myocardial infarct size. Developing new therapies to further reduce left ventricular remodeling after the acute event is another approach to preserving structure and function of the heart after infarction. Such therapy may include chronic administration of pharmacologic agents and/or therapies developed from the field of regenerative cardiology, including cellular or non-cellular materials such as extracellular matrix. The optimal therapy will be to administer agents that both reduce myocardial infarct size in the acute phase of infarction as well as reduce adverse left ventricular remodeling during the chronic or healing phase of myocardial infarction. Such a dual approach will help optimize the preservation of both cardiac structure and function.
Antioxidant and anti-inflammatory effects of intravenously injected adipose derived mesenchymal stem cells in dogs with acute spinal cord injury.Friday, November 27, 2015
Kim Y, Jo SH, Kim WH, Kweon OK,
Stem cell research & therapy. 25-11-2015
Our results suggest that early intravenous injection of AD-MSCs after acute SCI may prevent further damage through enhancement of antioxidative and anti-inflammatory mechanisms, without inducing adverse effects. Additionally, this treatment could also be used as an alternative intravenous treatment modality for acute SCI.
On signaling pathways: hematopoietic stem cell specification from hemogenic endothelium.Friday, November 27, 2015
Yan L, He H,
Science China. Life sciences. 26-Nov-2015
Hematopoietic stem cells (HSCs) are specified and generated during the embryonic development and have remarkable potential to replenish the full set of blood cell lineages. Researchers have long been interested in clarifying the molecular events involved in HSC specification. Many studies have reported the development of methods for generating functional hematopoietic cells from pluripotent stem cells (PSCs-embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs)) for decades. However, the generation of HSCs with robust long-term repopulation potential remains a swingeing challenge, of which a major factor contributing to this failure is the difficulty to define the intraembryonic signals related to the specification of HSCs. Since HSCs directly derive from hemogenic endothelium, in this review, we summarize both in vivo and in vitro studies on conserved signaling pathways that control the specification of HSCs from hemogenic endothelial cells.
Hydrogel-based biosensors and sensing devices for drug delivery.Friday, November 27, 2015
Peppas NA, Van Blarcom DS,
Journal of controlled release : official journal of the Controlled Release Society. 20-Nov-2015
In the past 15years drug delivery devices have received added attention, not only as passive systems of drug delivery that respond to the needs of the health care provider or the patient but have an added advantage or an added characteristic of being triggered by an external process of recognition of a cause, a disease or an analyte that leads to a triggering mechanism for specific drug delivery. In this review, we will examine some of the pioneering work in this field, and speak on the use of biodegradable, environmentally-responsive hydrogels as sensing components in novel microscale devices.
The role of the seven clude drug components in the sleep-promoting effect of Yokukansan.Friday, November 27, 2015
Ogawa Y, Fujii Y, Sugiyama R, Konishi T,
Journal of ethnopharmacology. 20-Nov-2015
Results of this study show that all crude drug components of Yokukansan contribute to its sleep-promoting effects. This is the first report to show the role of the seven clude drug components in the sleep-inducing effects of Yokukansan.
Cryopreservation of equine mesenchymal stem cells in 95 % autologous serum and 5 % DMSO does not alter post-thaw growth or morphology in vitro compared to fetal bovine serum or allogeneic serum at 20 or 95 % and DMSO at 10 or 5.Friday, November 27, 2015
Mitchell A, Rivas KA, Smith R, Watts AE,
Stem cell research & therapy. 20-11-2015
Each of the serum sources could be used for short-term cryopreservation of equine bone marrow derived MSCs. Prior to clinical use, clinicians may prefer autologous serum and a lower concentration of DMSO.
Characterization of an Injury Induced Population of Muscle-Derived Stem Cell-Like Cells.Friday, November 27, 2015
Vojnits K, Pan H, Mu X, Li Y,
Scientific reports. 26-11-2015
We recently discovered a novel population of stem cells from the injured murine skeletal muscle. These injury induced muscle-derived stem cell-like cells (iMuSCs) are partially reprogrammed from differentiated myogenic cells and display a pluripotent-like state. The iMuSCs exhibit stem cell properties including the ability to differentiate into multiple lineages, such as neurogenic and myogenic differentiations; they also display a superior migration capacity that demonstrating a strong ability of muscle engraftment in vivo. IMuSCs express several pluripotent and myogenic stem cell markers; have the capability to form embryoid bodies and teratomas, and can differentiate into all three germ layers. Moreover, blastocyst microinjection showed that the iMuSCs contributed to chimeric embryos but could not complete germline transmission. Our results indicate that the iMuSCs are in a partially reprogrammed state of pluripotency, which are generated by the microenvironment of injured skeletal muscle.
Increased efficacy of intermediate-dose cytarabine + G-CSF compared to DHAP + G-CSF for stem cell mobilization in patients with lymphoma: an analysis by the polish lymphoma research group.Friday, November 27, 2015
Giebel S, Sadus-Wojciechowska M, Halaburda K, Drozd-Sokolowska J, Wierzbowska A, Najda J, Mendrek W, Sobczyk-Kruszelnicka M, Nowicki M, Holowiecki J, Czerw T,
Annals of hematology. 27-Nov-2015
Salvage regimens, like DHAP (dexamethasone, cytarabine, and cisplatin) are frequently used for stem cell mobilization in lymphoma. The aim of this study was to compare the efficacy of DHAP + G-CSF with intermediate-dose cytarabine (ID-AraC) + G-CSF, recently proposed as an alternative schedule. Consecutive patients with Hodgkin's or non-Hodgkin lymphoma who had received at least 2 lines of chemotherapy, mobilized with either DHAP (n = 51) or ID-AraC (n = 50) + G-CSF were included in the analysis. AraC was administered at the dose of 400 mg/m [1] bid intravenously for 2 days followed by filgrastim starting from day 5. In the AraC group, 96 % of patients collected at least 2 × 10 [2] CD34(+) cells/kg compared to 71 % in the DHAP group (p = 0.0006). The CD34(+) cell yield was 9.3 (0-30.3) × 10 [2]/kg vs. 5.6 (0-24.8) × 10 [2]/kg, respectively (p = 0.006). A single apheresis was sufficient to achieve the threshold number of CD34(+) cells in 82 % of the cases after AraC compared to 45 % after DHAP (p = 0.001). We conclude that stem cell mobilization using ID-AraC is associated with a significantly higher efficacy than DHAP, allowing for collection of the transplant material in almost all patients with lymphoma. Our observation suggests that ID-AraC + G-CSF may be a preferable mobilization regimen in this setting.
Characterization of Ambra1 in asexual cycle of a non-vertebrate chordate, the colonial tunicate Botryllus schlosseri, and phylogenetic analysis of the protein group in Bilateria.Friday, November 27, 2015
Gasparini F, Skobo T, Benato F, Gioacchini G, Voskoboynik A, Carnevali O, Manni L, Valle LD,
Molecular phylogenetics and evolution. 20-Nov-2015
Ambra1 is a positive regulator of autophagy, a lysosome-mediated degradative process involved both in physiological and pathological conditions. Nowadays, Ambra1 has been characterized only in mammals and zebrafish. Through bioinformatics searches and targeted cloning, we report the identification of the complete Ambra1 transcript in a non-vertebrate chordate, the tunicate Botryllus schlosseri. Tunicata is the sister group of Vertebrata and the only chordate group possessing species that reproduce also by blastogenesis (asexual reproduction). B. schlosseri Ambra1 deduced amino acid sequence is shorter than vertebrate homologues but still contains the typical WD40 domain. qPCR analyses revealed that the level of B. schlosseri Ambra1 transcription is temporally regulated along the colonial blastogenetic cycle. By means of similarity searches we identified Wdr5 and Katnb1 as proteins evolutionarily associated to Ambra1. Phylogenetic analyses on Bilateria indicate that: Wdr5 is the most related to Ambra1, so that they may derive from an ancestral gene, ii) Ambra1 forms a group of ancient genes evolved before the radiation of the taxon, iii) these orthologous Ambra1 share the two conserved WD40/YVTN repeat-like-containing domains, and iv) they are characterized by ancient duplications of WD40 repeats within the N-terminal domain.
Expanded endothelial progenitor cells mitigate lung injury in septic mice.Friday, November 27, 2015
Güldner A, Maron-Gutierrez T, Abreu SC, Xisto DG, Senegaglia AC, Barcelos PR, Silva JD, Brofman P, Gama de Abreu M, Rocco PR,
Stem cell research & therapy. 20-11-2015
Endothelial progenitor cells (EPCs) improve survival and reduce organ failure in cecal ligation and puncture-induced sepsis; however, expanded EPCs may represent an even better approach for vascular repair. To date, no study has compared the effects of non-expanded EPCs (EPC-NEXP) with those of expanded EPCs (EPC-EXP) and mesenchymal stromal cells of human (MSC-HUMAN) and mouse (MSC-MICE) origin in experimental sepsis. One day after cecal ligation and puncture sepsis induction, BALB/c mice were randomized to receive saline, EPC-EXP, EPC-NEXP, MSC-HUMAN or MSC-MICE (1 × 10(5)) intravenously. EPC-EXP, EPC-NEXP, MSC-HUMAN, and MSC-MICE displayed differences in phenotypic characterization. On days 1 and 3, cecal ligation and puncture mice showed decreased survival rate, and increased elastance, diffuse alveolar damage, and levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor-α, vascular endothelial growth factor, and platelet-derived growth factor in lung tissue. EPC-EXP and MSC-HUMAN had reduced elastance, diffuse alveolar damage, and platelet-derived growth factor compared to no-cell treatment. Tumor necrosis factor-α levels decreased in the EPC-EXP, MSC-HUMAN, and MSC-MICE groups. IL-1β levels decreased in the EPC-EXP group, while IL-10 decreased in the MSC-MICE. IL-6 levels decreased both in the EPC-EXP and MSC-MICE groups. Vascular endothelial growth factor levels were reduced regardless of therapy. In conclusion, EPC-EXP and MSC-HUMAN yielded better lung function and reduced histologic damage in septic mice.
Robust reconstitution of TB-specific polyfunctional CD4+ T-cell responses and rising systemic IL-6 in paradoxical TB-IRIS.Friday, November 27, 2015
Ravimohan S, Tamuhla N, Nfanyana K, Steenhoff AP, Letlhogile R, Frank I, MacGregor RR, Gross R, Weissman D, Bisson GP,
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 26-Nov-2015
 Rapid expansion of TB-specific polyfunctional CD4(+) T-cell responses, likely linked to increases in IL-6, is associated with development of paradoxical TB-IRIS.
Assessment of the potential of a high frequency acoustomicrofluidic nebulisation platform for inhaled stem cell therapy.Friday, November 27, 2015
Alhasan L, Qi A, Rezk AR, Yeo LY, Chan PP,
Integrative biology : quantitative biosciences from nano to macro. 27-Nov-2015
Despite the promise of stem cell therapy for lung therapeutics and repair, there are few viable means for directly delivering stem cells to locally target the respiratory airways via inhalation. This is not surprising given the significant challenges in aerosolising stem cells, particularly given their susceptibility to damage under the large stresses involved in the nebulisation process. Here, we present promising results using a microfluidic acoustic nebulisation platform that is not only low cost and portable, but also its high MHz order frequencies are effective for preserving the structural and functional integrity of mesenchymal stem cells (MSCs) during the nebulisation process. This is verified through an assessment of the viability, structure, metabolic activity, proliferation ability and genetic makeup of the nebulised MSCs using a variety of assays, including cell viability staining, flow cytometry, reverse transcription and quantitative polymerase chain reaction, and immunophenotyping, thus demonstrating the platform as a promising method for efficient pulmonary stem cell delivery.
Mapping of Brain lipid binding protein (Blbp) in the brain of adult zebrafish, co-expression with aromatase B and links with proliferation.Friday, November 27, 2015
Diotel N, Vaillant C, Kah O, Pellegrini E,
Gene expression patterns : GEP. 20-Nov-2015
Adult fish exhibit a strong neurogenic capacity due to the persistence of radial glial progenitor cells. In zebrafish, radial glial cells display well-established markers such as the estrogen-synthesizing enzyme (AroB) and the brain lipid binding protein (Blbp), which is known to strongly bind omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA). While Blpb is mainly described in the telencephalon of adult zebrafish, its expression in the remaining regions of the brain is poorly documented. The present study was designed to further investigate Blbp expression in the brain, its co-expression with AroB, and its link with radial glial cells proliferation in zebrafish. We generated a complete and detailed mapping of Blbp expression in the whole brain and show its complete co-expression with AroB, except in some tectal and hypothalamic regions. By performing PCNA and Blbp immunohistochemistry on cyp19a1b-GFP (AroB-GFP) fish, we also demonstrated preferential Blbp expression in proliferative radial glial cells in almost all regions studied. To our knowledge, this is the first complete and detailed mapping of Blbp-expressing cells showing strong association between Blbp and radial glial cell proliferation in the adult brain of fish. Given that zebrafish is now recognized models for studying neurogenesis and brain repair, our data provide detailed characterization of Blbp in the entire brain and open up a broad field of research investigating the role of omega-3 polyunsaturated fatty acids in neural stem cell activity in fish.
Novel approach to target cancer stem cells for therapy.Friday, November 27, 2015
Rajanna A,
Medical hypotheses. 14-Nov-2015
Even though lots of efforts have been made to find different strategies for cancer treatments, currently available therapeutic approaches are chemotherapy, radiation and surgery or combination of these. These treatments prolonged the survival of patients but did not assure complete cure of the disease. Recent scientific evidences suggest that cancer stem cells (CSC) are responsible for recurrence, resistance and existence of this disease even after various therapeutic treatments. Therefore, we hypothesize that the best approach is to target CSCs along with cancer cells for complete remission of the disease. Before targeting these cells, studying their morphological, proliferation, behavioral aspects, physico-chemical interaction and characterizations are very important. For therapeutic approach the differentiation capacity of these cells to cancer cells with or without drugs is critical. To study basic parameters; the best approach would be aseptic sorting of CSCs from cancer cells based on specific cell surface markers by flowcytometer or magnetic cell sorter. The sorted cells have to be grown in culture conditions and treat with optimum concentrations of drugs to target CSC and cancer cell to find appropriate potential combination.
Ex Vivo Gene Therapy Using Human Mesenchymal Stem Cells to Deliver Growth Factors in the Skeletal Muscle of a Familial ALS Rat Model.Friday, November 27, 2015
Suzuki M, Svendsen CN,
Methods in molecular biology (Clifton, N.J.). 2016
Therapeutic protein and molecule delivery to target sites by transplanted human stem cells holds great promise for ex vivo gene therapy. Our group has demonstrated the therapeutic benefits of ex vivo gene therapy targeting the skeletal muscles in a transgenic rat model of familial amyotrophic lateral sclerosis (ALS). We used human mesenchymal stem cells (hMSCs) and genetically modified them to release neuroprotective growth factors such as glial cell line-derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF). Intramuscular growth factor delivery via hMSCs can enhance neuromuscular innervation and motor neuron survival in a rat model of ALS (SOD1(G93A) transgenic rats). Here, we describe the protocol of ex vivo delivery of growth factors via lentiviral vector-mediated genetic modification of hMSCs and hMSC transplantation into the skeletal muscle of a familial ALS rat model.
Controlling AAV Tropism in the Nervous System with Natural and Engineered Capsids.Friday, November 27, 2015
Castle MJ, Turunen HT, Vandenberghe LH, Wolfe JH,
Methods in molecular biology (Clifton, N.J.). 2016
More than one hundred naturally occurring variants of adeno-associated virus (AAV) have been identified, and this library has been further expanded by an array of techniques for modification of the viral capsid. AAV capsid variants possess unique antigenic profiles and demonstrate distinct cellular tropisms driven by differences in receptor binding. AAV capsids can be chemically modified to alter tropism, can be produced as hybrid vectors that combine the properties of multiple serotypes, and can carry peptide insertions that introduce novel receptor-binding activity. Furthermore, directed evolution of shuffled genome libraries can identify engineered variants with unique properties, and rational modification of the viral capsid can alter tropism, reduce blockage by neutralizing antibodies, or enhance transduction efficiency. This large number of AAV variants and engineered capsids provides a varied toolkit for gene delivery to the CNS and retina, with specialized vectors available for many applications, but selecting a capsid variant from the array of available vectors can be difficult. This chapter describes the unique properties of a range of AAV variants and engineered capsids, and provides a guide for selecting the appropriate vector for specific applications in the CNS and retina.
Small-Scale Recombinant Adeno-Associated Virus Purification.Friday, November 27, 2015
Burger C, Nash KR,
Methods in molecular biology (Clifton, N.J.). 2016
Recombinant adeno-associated virus (rAAV) vectors have become increasingly popular in research and clinical trials due to their efficient gene transfer and long-term expression in tissues including brain. In addition, rAAV has demonstrated an impressive safety profile in gene therapy trials. The emergence of rAAV serotypes with different cell tropisms and distribution properties has allowed scientists to tailor serotypes to specific experimental needs. AAV does not have a cytopathic effect; therefore, purification methods require extraction of the viral vector from the cell. This involves gradient ultracentrifugation of the cellular extract sometimes followed by chromatography. This chapter describes a small-scale production method for rAAV purification from ten to twenty 15 cm plates of human embryonic kidney-derived 293B cells (HEK 293) cells that can yield approximately 300 μl of a 5 × 10(12) to 1 × 10(13) genome copies/ml viral preparation final concentration.
Detection of aberrant hippocampal mossy fiber connections: Ex vivo mesoscale diffusion MRI and microtractography with histological validation in a patient with uncontrolled temporal lobe epilepsy.Friday, November 27, 2015
Modo M, Kevin Hitchens T, Liu JR, Richardson RM,
Human brain mapping. 27-Nov-2015
Understanding the neurobiology and functional connectivity of hippocampal structures is essential for improving the treatment of mesial temporal lobe epilepsy. At the macroscale, in vivo MRI often reveals hippocampal atrophy and decreased fractional anisotropy, whereas at the microscopic scale, there frequently is evidence of neuronal loss and gliosis. Mossy fiber sprouting in the dentate gyrus (DG), with evidence of glutamatergic synapses in the stratum moleculare (SM) putatively originating from granule cell neurons, may also be observed. This aberrant connection between the DG and SM could produce a reverberant excitatory circuit. However, this hypothesis cannot easily be evaluated using macroscopic or microscopic techniques. We here demonstrate that the ex vivo mesoscopic MRI of surgically excised hippocampi can bridge the explanatory and analytical gap between the macro- and microscopic scale. Specifically, diffusion- and T2 -weighted MRI can be integrated to visualize a cytoarchitecture that is akin to immunohistochemistry. An appropriate spatial resolution to discern individual cell layers can then be established. Processing of diffusion tensor images using tractography detects extra- and intrahippocampal connections, hence providing a unique systems view of the hippocampus and its connected regions. Here, this approach suggests that there is indeed an aberrant connection between the DG and SM, supporting the sprouting hypothesis of a reverberant excitatory network. Mesoscopic ex vivo MR imaging hence provides an exciting new avenue to study hippocampi from treatment-resistant patients and allows exploration of existing hypotheses, as well as the development of new treatment strategies based on these novel insights. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.
Allogeneic MSC persistence may not be necessary for a beneficial effect in burn wound healing.Friday, November 27, 2015
Whelan D, Caplice NM, Clover AJ,
Burns : journal of the International Society for Burn Injuries. 20-Nov-2015
Time-dependent effects of clinical predictors in unrelated hematopoietic stem cell transplantation.Friday, November 27, 2015
Fuerst D, Mueller C, Beelen DW, Neuchel C, Tsamadou C, Schrezenmeier H, Mytilineos J,
Haematologica. 26-Nov-2015
Hematopoietic stem cell transplantation is a multifactorial process. Some of the predictors exhibit time-dependent effects. We present a systematic analysis and description of selected clinical predictors influencing outcome in a time-dependent manner based on a registry data analysis from the German Registry for Stem Cell Transplantation. A total of 14951 patients with acute myeloid leukemia, acute lymphocytic leukemia, myelodysplastic syndrome and non-Hodgkin lymphoma transplanted with peripheral blood stem cells or bone marrow grafts were included. Multivariate Cox-regression models were tested for time-dependent effects within each diagnosis group. Predictors not satisfying the proportional hazards assumption were modeled in a time-dependent manner, extending the Cox-regression models. Similar patterns occurred in all diagnosis groups. Patients with a poor Karnofsky performance score (<80) had a high risk for early mortality until day 139 following transplantation (HR 2.42, CI 2.19-2.68, p<0.001) compared to patients with a good Karnofsky performance score (80-100). Afterwards the risk reduced to HR 1.43, CI 1.25-1.63, p<0.001. A lower mortality risk was found for patients after conditioning treatment with reduced intensity until day 120 post-transplant (HR: 0.81 CI 0.75-0.88, p<0.001). A slightly higher risk could be shown for these patients afterwards. Similarly, patients who had received a PBSC graft exhibited a significantly lower mortality risk until day 388 post transplantation (HR 0.79, CI 0.73-0.85, p<0.001), reversing to a significantly higher risk afterwards (HR 1.23, CI 1.08-1.40, p=0.002). Integrating time-dependency in regression models allows more accurate description and quantification of clinical predictors, which may aid risk assessment and patient counseling.
Polymorphism in TGFB1 is associated with worse non-relapse mortality and overall survival after stem cell transplantation with unrelated donors.Friday, November 27, 2015
Arrieta-Bolaños E, Mayor NP, Marsh SG, Madrigal JA, Apperley JF, Kirkland K, Mackinnon S, Marks DI, McQuaker G, Perry J, Potter MN, Russell NH, Thomson K, Shaw BE,
Haematologica. 26-Nov-2015
Transforming growth factor β-1, encoded by the TGFB1 gene, is a cytokine that plays a central role in many physiologic and pathogenic processes. We have sequenced TGFB1 regulatory region and assigned allelic genotypes in a large cohort of hematopoietic stem cell transplantation patients and donors. In this study we analyzed 522 unrelated donor-patient pairs and examined the combined effect of all the common polymorphisms in this genomic region. In univariate analysis, we found that patients carrying a specific allele, p001, showed significantly reduced overall survival (5-year overall survival 30.7% for p001/p001 patients vs 41.6% others; p=0.032) and increased non-relapse mortality (1-year non-relapse mortality: 39.0% vs 25.4%; p=0.039) after transplantation. In multivariate analysis, the presence of a p001/p001 genotype in patients was confirmed as an independent factor for reduced overall survival (hazard ratio=1.53 [1.04-2.24]; p=0.031), and increased non-relapse mortality (hazard ratio=1.73 [1.06-2.83]; p=0.030). In functional experiments we found a trend towards a higher percentage of surface transforming growth factor β-1-positive regulatory T cells after activation when the cells had a p001 allele (p=0.07). Higher or lower production of transforming growth factor β-1 in the inflammatory context of hematopoietic stem cell transplantation may influence the development of complications in these patients. Findings indicate that TGFB1 genotype could potentially be of use as a prognostic factor in hematopoietic stem cell transplantation risk assessment algorithms.
The ATM-BID pathway plays a critical role in the DNA damage response by regulating mitochondria metabolism.Friday, November 27, 2015
Gross A, Zaltsman Y, Maryanovich M,
Cell death and differentiation. 27-Nov-2015
HIV, highly active antiretroviral therapy and the heart: a cellular to epidemiological review.Friday, November 27, 2015
Lambert CT, Sandesara PB, Hirsh B, Shaw LJ, Lewis W, Quyyumi AA, Schinazi RF, Post WS, Sperling L,
HIV medicine. 26-Nov-2015
The advent of potent highly active antiretroviral therapy (HAART) for persons infected with HIV-1 has led to a "new" chronic disease with complications including cardiovascular disease (CVD). CVD is a significant cause of morbidity and mortality in persons with HIV infection. In addition to traditional risk factors such as smoking, hypertension, insulin resistance and dyslipidaemia, infection with HIV is an independent risk factor for CVD. This review summarizes: (1) the vascular and nonvascular cardiac manifestations of HIV infection; (2) cardiometabolic effects of HAART; (3) atherosclerotic cardiovascular disease (ASCVD) risk assessment, prevention and treatment in persons with HIV-1 infection.
Reprogramming the tumor microenvironment to enhance adoptive cellular therapy.Friday, November 27, 2015
Beavis PA, Slaney CY, Kershaw MH, Gyorki D, Neeson PJ, Darcy PK,
Seminars in immunology. 20-Nov-2015
The frontiers of cancer immunotherapy are extending in terms of both the range of cancer types that can potentially be targeted and the types of therapeutics that are in clinical development. The use of adoptive cellular therapy (ACT) and its derivative, chimeric antigen receptor (CAR) T cells, is currently limited to hematological malignancies and immunogenic cancers such as melanoma and renal cell carcinoma. Although ACT utilizing ex vivo expanded tumor-infiltrating lymphocytes (TIL) or engineered CAR/TCR T cells have undergone clinical trials for other solid cancers, their efficacy to date has been limited. This may be due, in part, to the immunosuppressive nature of the tumor microenvironment. The development of novel combination approaches which target the immunosuppressive network engineered by tumors has raised the possibility of using ACT for a broader range of cancers. This review summarizes the potential of such strategies and outlines the clinical relevance of these observations.
New Approaches to Biological Pacemakers: Links to Sinoatrial Node Development.Friday, November 27, 2015
Vedantham V,
Trends in molecular medicine. 13-Nov-2015
Irreversible degeneration of the cardiac conduction system is a common disease that can cause activity intolerance, fainting, and death. While electronic pacemakers provide effective treatment, alternative approaches are needed when long-term indwelling hardware is undesirable. Biological pacemakers comprise electrically active cells that functionally integrate with the heart. Recent findings on cardiac pacemaker cells (PCs) within the sinoatrial node (SAN), along with developments in stem cell technology, have opened a new era in biological pacing. Recent experiments that have derived PC-like cells from non-PCs have brought the field closer than ever before to biological pacemakers that can faithfully recapitulate SAN activity. In this review, I discuss these approaches in the context of SAN biology and address the potential for clinical translation.
A minimal fate-selection switch.Friday, November 27, 2015
Weinberger LS,
Current opinion in cell biology. 20-Nov-2015
To preserve fitness in unpredictable, fluctuating environments, a range of biological systems probabilistically generate variant phenotypes-a process often referred to as 'bet-hedging', after the financial practice of diversifying assets to minimize risk in volatile markets. The molecular mechanisms enabling bet-hedging have remained elusive. Here, we review how HIV makes a bet-hedging decision between active replication and proviral latency, a long-lived dormant state that is the chief barrier to an HIV cure. The discovery of a virus-encoded bet-hedging circuit in HIV revealed an ancient evolutionary role for latency and identified core regulatory principles, such as feedback and stochastic 'noise', that enable cell-fate decisions. These core principles were later extended to fate selection in stem cells and cancer, exposed new therapeutic targets for HIV, and led to a potentially broad strategy of using 'noise modulation' to redirect cell fate.
HSC Aging and Senescent Immune Remodeling.Friday, November 27, 2015
Denkinger MD, Leins H, Schirmbeck R, Florian MC, Geiger H,
Trends in immunology. 20-Nov-2015
Aging-associated changes in the function of the immune system are referred to as senescent immune remodeling (SIR). Here we review the current understanding on the cellular and molecular mechanisms underlying SIR. We focus on aging-associated changes in T and B cells, and discuss recent evidence supporting the notion that aging of the hematopoietic stem cell (HSC) compartment directly contributes to SIR due to aging-associated alterations in stem cell differentiation. We conclude by outlining strategies to attenuate SIR, including approaches to rejuvenate HSCs, which may open new avenues for targeting SIR in the clinic.
Does PGC1α/FNDC5/BDNF Elicit the Beneficial Effects of Exercise on Neurodegenerative Disorders?Friday, November 27, 2015
Jodeiri Farshbaf M, Ghaedi K, Megraw TL, Curtiss J, Shirani Faradonbeh M, Vaziri P, Nasr-Esfahani MH,
Neuromolecular medicine. 26-Nov-2015
Neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases have high prevalence among the elderly. Many strategies have been established to alleviate the symptoms experienced by affected individuals. Recent studies have shown that exercise helps patients with neurological disorders to regain lost physical abilities. PGC1α/FNDC5/BDNF has emerged recently as a critical pathway for neuroprotection. PGC1α is a highly conserved co-activator of transcription factors that preserves and protects neurons against destruction. PGC1α regulates FNDC5 and its processed and secreted peptide Irisin, which has been proposed to play a critical role in energy expenditure and to promote neural differentiation of mouse embryonic stem cells. FNDC5 may also increase the expression of the neurotrophic factor BDNF, a neuroprotective agent, in the hippocampus. BDNF is secreted from hippocampus, amygdala, cerebral cortex and hypothalamus neurons and initiates intracellular signaling pathways through TrkB receptors. These pathways have positive feedback on CREB activities and lead to enhancement in PGC1α expression in neurons. Therefore, FNDC5 could behave as a key regulator in neuronal survival and development. This review presents recent findings on the PGC1α/FNDC5/BDNF pathway and its role in neuroprotection, and discusses the controversial promise of irisin as a mediator of the positive benefits of exercise.
Involvement of autophagy upregulation in 3,4-methylenedioxymethamphetamine ('ecstasy')-induced serotonergic neurotoxicity.Friday, November 27, 2015
Li IH, Ma KH, Kao TJ, Lin YY, Weng SJ, Yen TY, Chen LC, Huang YS,
Neurotoxicology. 20-Nov-2015
It has been suggested that autophagy plays pathogenetic roles in cerebral ischemia, brain trauma, and neurodegenerative disorders. 3,4-Methylenedioxymethamphetamine (MDMA or ecstasy) is an illicit drug that causes long-term serotonergic neurotoxicity in the brain. Apoptosis and necrosis have been implicated in MDMA-induced neurotoxicity, but the role of autophagy in MDMA-elicited serotonergic toxicity has not been investigated. The present study aimed to examine the contribution of autophagy to neurotoxicity in serotonergic neurons in in vitro and in vivo animal models challenged with MDMA. Here, we demonstrated that in cultured rat serotonergic neurons, MDMA exposure induced LC3B-densely stained autophagosome formation, accompanying by a decrease in neurite outgrowth. Autophagy inhibitor 3-methyladenine (3-MA) significantly attenuated MDMA-induced autophagosome accumulation, and ameliorated MDMA-triggered serotonergic neurite damage and neuron death. In contrast, enhanced autophagy flux by rapamycin or impaired autophagosome clearance by bafilomycin A1 led to more autophagosome accumulation in serotonergic neurons and aggravated neurite degeneration. In addition, MDMA-induced autophagy activation in cultured serotonergic neurons might be mediated by serotonin transporter (SERT). In an in vivo animal model administered MDMA, neuroimaging showed that 3-MA protected the serotonin system against MDMA-induced downregulation of SERT evaluated by animal-PET with 4-[(18)F]-ADAM, a SERT radioligand. Taken together, our results demonstrated that MDMA triggers upregulation of autophagy in serotonergic neurons, which appears to be detrimental to neuronal growth.
Molecular Basis of Laminin-Integrin Interactions.Friday, November 27, 2015
Yamada M, Sekiguchi K,
Current topics in membranes. 2015
Laminins are composed of three polypeptide chains, designated as α, β, and γ. The C-terminal region of laminin heterotrimers, containing coiled-coil regions, short tails, and laminin globular (LG) domains, is necessary and sufficient for binding to integrins, which are the major laminin receptor class. Laminin recognition by integrins critically requires the α chain LG domains and a glutamic acid residue of the γ chain at the third position from the C-terminus. Furthermore, the C-terminal region of the β chain contains a short amino acid sequence that modulates laminin affinity for integrins. Thus, all three of the laminin chains act cooperatively to facilitate integrin binding. Mammals possess 5 α (α1-5), 3 β (β1-3), and 3 γ (γ1-3) chains, combinations of which give rise to 16 distinct laminin isoforms. Each isoform is expressed in a tissue-specific and developmental stage-specific manner, exerting its functions through binding of integrins. In this review, we detail the current knowledge surrounding the molecular basis and physiological relevance of specific interactions between laminins and integrins, and describe the mechanisms underlying laminin action through integrins.
Incidental diffuse low-grade gliomas: from early detection to preventive neuro-oncological surgery.Friday, November 27, 2015
Lima GL, Zanello M, Mandonnet E, Taillandier L, Pallud J, Duffau H,
Neurosurgical review. 27-Nov-2015
Although a large amount of data supports early surgical resection for symptomatic diffuse low-grade glioma, the therapeutic strategy is still a matter of debate regarding incidentally discovered diffuse low-grade glioma. Indeed, early and "preventive" surgery has recently been proposed in asymptomatic patients with silent diffuse low-grade glioma with better outcomes. The present review discusses the importance of an early diagnosis and of a preventive surgical treatment to improve the outcomes of incidental diffuse low-grade glioma and suggests the possible relevance of a tailored screening policy.
Clinical Trials of Adult Stem Cell Therapy in Patients with Ischemic Stroke.Friday, November 27, 2015
Bang OY,
Journal of clinical neurology (Seoul, Korea). 26-Nov-2015
Stem cell therapy is considered a potential regenerative strategy for patients with neurologic deficits. Studies involving animal models of ischemic stroke have shown that stem cells transplanted into the brain can lead to functional improvement. With current advances in the understanding regarding the effects of introducing stem cells and their mechanisms of action, several clinical trials of stem cell therapy have been conducted in patients with stroke since 2005, including studies using mesenchymal stem cells, bone marrow mononuclear cells, and neural stem/progenitor cells. In addition, several clinical trials of the use of adult stem cells to treat ischemic stroke are ongoing. This review presents the status of our understanding of adult stem cells and results from clinical trials, and introduces ongoing clinical studies of adult stem cell therapy in the field of stroke.
Self-renewal of human embryonic stem cells on defined synthetic electrospun nanofibers.Friday, November 27, 2015
Kumar D, Dale TP, Yang Y, Forsyth NR,
Biomedical materials (Bristol, England). 26-11-2015
Human embryonic stem cells (hESCs) are conventionally expanded and maintained in vitro on biological substrates. Synthetic electrospun polymer nanofibers have the potential to act as non-biological substrates in the culture of hESCs. Three synthetic, FDA approved polymers: poly-ɛ-caprolactone (PCL), poly-L-lactic acid (PLLA) and poly lactic-co-glycolic acid (PLGA) were electrospun as nanofibers (random or aligned conformations) on glass coverslips and their supportive role in hESC culture examined. Clonogenicity experiments demonstrated that nanofibrous scaffolds (PCL aligned and random, PLLA aligned and PLGA aligned) supported hESC adhesion and expansion. A significantly greater number of colonies were observed on PCL-aligned nanofibrous scaffolds in comparison to PLLA-aligned and PLGA-aligned substrates (p  <  0.05). hESC colonies were significantly larger on PCL aligned nanofibrous substrates when compared to other polymer substrates (p  < 0.05-0.001), where fiber diameter played a pivotal role in support of hESC clonogenicity (on PCL). Retention of pluripotentiality was confirmed by expression of Alkaline phosphatase, OCT-3/4 and Nanog expression on PCL scaffolds and the expression of transcripts representative of mesoderm (ACTC1), ectoderm (SOX1) and endoderm (AFP) during subsequent spontaneous in vitro differentiation. These results demonstrate the potential of nanofibers as xeno-free scaffolds supportive of hESC adhesion, self-renewal and differentiation in in vitro culture conditions.
Composite hydrogels of polyacrylamide and crosslinked pH-responsive micrometer-sized hollow particles.Friday, November 27, 2015
Pafiti K, Cui Z, Carney L, Freemont AJ, Saunders BR,
Soft matter. 27-Nov-2015
Whilst hydrogels and hollow particles both continue to attract much attention in the literature there are few examples of hydrogel composites containing hollow particles. Here, we study composite polyacrylamide (PAAm) hydrogels containing micrometer-sized pH-responsive shell-crosslinked hollow particles (abbreviated as HPXL) based on poly(methylmethacrylate-co-methacrylic acid) functionalised with glycidyl methacrylate (GMA). The HPXL particles were prepared using our scaleable emulsion template method and inclusion of GMA was found to promote spherical hollow particle formation. The pendant vinyl groups from GMA enabled shell-crosslinked hollow particles to be prepared prior to formation of the PAAm/HPXL composite gels. The morphologies of the particles and composite gels were studied by optical microscopy, confocal laser scanning microscopy and scanning electron microscopy. Dynamic rheology measurements for the composite gels showed that the modulus variation with HPXL concentration could be described by a percolation model with a HPXL percolation threshold concentration of 4.4 wt% and a scaling exponent of 2.6. The composite gels were pH-responsive and largely maintained their mechanical properties over the pH range 4.0 to 8.0. Because the composite gels had tuneable mechanical properties (with modulus values up to 530 kPa) and were pH-responsive they are potential candidates for future wound healing or membrane applications.
Localized gene expression analysis during sprouting angiogenesis in mouse embryoid bodies using a double barrel carbon probe.Friday, November 27, 2015
Ito H, Nashimoto Y, Zhou Y, Takahashi Y, Ino K, Shiku H, Matsue T,
Analytical chemistry. 27-Nov-2015
The mouse embryonic stem (ES) cell-derived angiogenesis model is widely used as a 3D model, reproducing cell-cell interactions in the living body. Previously, many methods to analyze localized cellular function, including in situ hybridization and laser cap-ture microdissection, have been reported. In this study, we achieved a collection of localized cells from the angiogenesis model in hydrogel. The gene expression profiles of the endothelial cells derived from mouse ES cells were evaluated. First, we collected localized cells from the live tissue model embedded in hydrogel using the double barrel carbon probe (DBCP) and quantified mRNA expression. Second, we found that vascular marker genes were expressed at a much higher level in sprouting vessels than in the central core of the embryoid body because the cells in sprouting vessels might significantly differentiate into endothelial linages, including tip/stalk cells. Third, the gene expression levels tended to be different between the top and middle regions in the sprouting vessel due to the difference in the degree of differentiation in these regions. At the top region of the vessel, both the tip and stalk cells were present. The cells in the middle region became more mature. Collectively, these results show that DBCP is very useful for analyzing localized gene expression in cells collected from 3D live tissues embedded in hydrogel. This technique can be applied to comprehensive gene expression analyses in the medical field.
Enhanced Homing of CXCR-4 Modified Bone Marrow-derived Mesenchymal Stem Cells to Acute Kidney Injury Tissues by Micro-bubble-mediated Ultrasound Exposure.Friday, November 27, 2015
Wang G, Zhang Q, Zhuo Z, Wu S, Xu Y, Zou L, Gan L, Tan K, Xia H, Liu Z, Gao Y,
Ultrasound in medicine & biology. 20-Nov-2015
Although the curative effects of bone marrow stromal cells (BMSCs) for acute kidney injury (AKI) have been recognized, their in vivo reparative capability is limited by the low levels of targeted homing and retention of intravenous injected cells. Stromal cell-derived factor-1 (SDF-1) plays an important role in stem cell homing and retention through interaction with its specific functional receptor, CXCR4, which is presumably related to the poor homing in AKI therapy. However, most of the functional CXCR4 chemokine receptors are lost upon in vitro culturing. Ultrasound-targeted micro-bubble destruction (UTMD) has become one of the most promising strategies for the targeted delivery of drugs and genes. To improve BMSC homing to AKI kidneys, we isolated and cultured rat BMSCs to third passage and enhanced CXCR-4 transfection efficiency in vitro by applying UTMD and polyethylenimine. Transwell migration assay showed that the migration ability of CXCR4-modified BMSCs was nine-fold higher than controls. Then, mercuric chloride-induced AKI rats were injected with transfected BMSCs through their tail veins. We showed that enhanced homing and retention of BMSCs were observed in the CXCR-4 modified group compared with other groups at 1, 2 and 3 d post-treatment. Collectively, our data indicated that UTMD was an effective method to increase BMSCs' engraftment to AKI kidney tissues by increasing CXCR-4 expression.
Fibrillin-1 microfibrils influence adult bone marrow hematopoiesis.Friday, November 27, 2015
Smaldone S, Bigarella CL, Del Solar M, Ghaffari S, Ramirez F,
Matrix biology : journal of the International Society for Matrix Biology. 20-Nov-2015
We have recently demonstrated that fibrillin-1 assemblies regulate the fate of skeletal stem cells (aka, mesenchymal stem cells [MSCs]) by modulating TGFβ activity within the microenvironment of adult bone marrow niches. Since MSCs can also influence hematopoietic stem cell (HSC) activities, here we investigated adult hematopoiesis in mice with Cre-mediated inactivation of the fibrillin-1 (Fbn1) gene in the mesenchyme of the forming limbs (Fbn1(Prx1-/-) mice). Analyses of 3-month-old Fbn1(Prx1-/-) mice revealed a statistically significant increase of circulating red blood cells, which a differentiation assay correlated with augmented erythropoiesis. This finding, together with evidence of fibrillin-1 deposition in erythroblastic niches, supported the notion that this extracellular matrix protein normally restricts differentiation of erythroid progenitors. Whereas flow cytometry measurements identified a decreased HSC frequency in mutant relative to wild type mice, no appreciable differences were noted with regard to the relative abundance and differentiation potential of myeloid progenitor cells. Together these findings implied that fibrillin-1 normally promotes HSC expansion but does not influence cell lineage commitment. Since local TGFβ hyperactivity has been associated with abnormal osteogenesis in Fbn1(Prx1-/-) mice, 1-month-old mutant and wild type animals were systemically treated for 8weeks with either a pan-TGF-β-neutralizing antibody or an antibody of the same IgG1 isotype. The distinct outcomes of these pharmacological interventions strongly suggest that fibrillin-1 differentially modulates TGFβ activity in HSC vs. erythroid niches.
Creating Patient-Specific Neural Cells for the In Vitro Study of Brain Disorders.Friday, November 27, 2015
Brennand KJ, Marchetto MC, Benvenisty N, Brüstle O, Ebert A, Izpisua Belmonte JC, Kaykas A, Lancaster MA, Livesey FJ, McConnell MJ, McKay RD, Morrow EM, Muotri AR, Panchision DM, Rubin LL, Sawa A, Soldner F, Song H, Studer L, Temple S, Vaccarino FM, Wu J, Vanderhaeghen P, Gage FH, Jaenisch R,
Stem cell reports. 20-Nov-2015
As a group, we met to discuss the current challenges for creating meaningful patient-specific in vitro models to study brain disorders. Although the convergence of findings between laboratories and patient cohorts provided us confidence and optimism that hiPSC-based platforms will inform future drug discovery efforts, a number of critical technical challenges remain. This opinion piece outlines our collective views on the current state of hiPSC-based disease modeling and discusses what we see to be the critical objectives that must be addressed collectively as a field.
Gap Junctional Blockade Stochastically Induces Different Species-Specific Head Anatomies in Genetically Wild-Type Girardia dorotocephala Flatworms.Friday, November 27, 2015
Emmons-Bell M, Durant F, Hammelman J, Bessonov N, Volpert V, Morokuma J, Pinet K, Adams DS, Pietak A, Lobo D, Levin M,
International journal of molecular sciences. 20-11-2015
The shape of an animal body plan is constructed from protein components encoded by the genome. However, bioelectric networks composed of many cell types have their own intrinsic dynamics, and can drive distinct morphological outcomes during embryogenesis and regeneration. Planarian flatworms are a popular system for exploring body plan patterning due to their regenerative capacity, but despite considerable molecular information regarding stem cell differentiation and basic axial patterning, very little is known about how distinct head shapes are produced. Here, we show that after decapitation in G. dorotocephala, a transient perturbation of physiological connectivity among cells (using the gap junction blocker octanol) can result in regenerated heads with quite different shapes, stochastically matching other known species of planaria (S. mediterranea, D. japonica, and P. felina). We use morphometric analysis to quantify the ability of physiological network perturbations to induce different species-specific head shapes from the same genome. Moreover, we present a computational agent-based model of cell and physical dynamics during regeneration that quantitatively reproduces the observed shape changes. Morphological alterations induced in a genomically wild-type G. dorotocephala during regeneration include not only the shape of the head but also the morphology of the brain, the characteristic distribution of adult stem cells (neoblasts), and the bioelectric gradients of resting potential within the anterior tissues. Interestingly, the shape change is not permanent; after regeneration is complete, intact animals remodel back to G. dorotocephala-appropriate head shape within several weeks in a secondary phase of remodeling following initial complete regeneration. We present a conceptual model to guide future work to delineate the molecular mechanisms by which bioelectric networks stochastically select among a small set of discrete head morphologies. Taken together, these data and analyses shed light on important physiological modifiers of morphological information in dictating species-specific shape, and reveal them to be a novel instructive input into head patterning in regenerating planaria.
Molecular, Cellular and Functional Effects of Radiation-Induced Brain Injury: A Review.Friday, November 27, 2015
Balentova S, Adamkov M,
International journal of molecular sciences. 24-11-2015
Radiation therapy is the most effective non-surgical treatment of primary brain tumors and metastases. Preclinical studies have provided valuable insights into pathogenesis of radiation-induced injury to the central nervous system. Radiation-induced brain injury can damage neuronal, glial and vascular compartments of the brain and may lead to molecular, cellular and functional changes. Given its central role in memory and adult neurogenesis, the majority of studies have focused on the hippocampus. These findings suggested that hippocampal avoidance in cranial radiotherapy prevents radiation-induced cognitive impairment of patients. However, multiple rodent studies have shown that this problem is more complex. As the radiation-induced cognitive impairment reflects hippocampal and non-hippocampal compartments, it is of critical importance to investigate molecular, cellular and functional modifications in various brain regions as well as their integration at clinically relevant doses and schedules. We here provide a literature overview, including our previously published results, in order to support the translation of preclinical findings to clinical practice, and improve the physical and mental status of patients with brain tumors.
Multi-Functional Macromers for Hydrogel Design in Biomedical Engineering and Regenerative Medicine.Friday, November 27, 2015
Hacker MC, Nawaz HA,
International journal of molecular sciences. 24-11-2015
Contemporary biomaterials are expected to provide tailored mechanical, biological and structural cues to encapsulated or invading cells in regenerative applications. In addition, the degradative properties of the material also have to be adjustable to the desired application. Oligo- or polymeric building blocks that can be further cross-linked into hydrogel networks, here addressed as macromers, appear as the prime option to assemble gels with the necessary degrees of freedom in the adjustment of the mentioned key parameters. Recent developments in the design of multi-functional macromers with two or more chemically different types of functionalities are summarized and discussed in this review illustrating recent trends in the development of advanced hydrogel building blocks for regenerative applications.
Application of Wnt Pathway Inhibitor Delivering Scaffold for Inhibiting Fibrosis in Urethra Strictures: In Vitro and in Vivo Study.Friday, November 27, 2015
Zhang K, Guo X, Zhao W, Niu G, Mo X, Fu Q,
International journal of molecular sciences. 19-11-2015
Objective: To evaluate the mechanical property and biocompatibility of the Wnt pathway inhibitor (ICG-001) delivering collagen/poly(l-lactide-co-caprolactone) (P(LLA-CL)) scaffold for urethroplasty, and also the feasibility of inhibiting the extracellular matrix (ECM) expression in vitro and in vivo. Methods: ICG-001 (1 mg (2 mM)) was loaded into a (P(LLA-CL)) scaffold with the co-axial electrospinning technique. The characteristics of the mechanical property and drug release fashion of scaffolds were tested with a mechanical testing machine (Instron) and high-performance liquid chromatography (HPLC). Rabbit bladder epithelial cells and the dermal fibroblasts were isolated by enzymatic digestion method. (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay) and scanning electron microscopy (SEM) were used to evaluate the viability and proliferation of the cells on the scaffolds. Fibrolasts treated with TGF-β1 and ICG-001 released medium from scaffolds were used to evaluate the anti-fibrosis effect through immunofluorescence, real time PCR and western blot. Urethrography and histology were used to evaluate the efficacy of urethral implantation. Results: The scaffold delivering ICG-001 was fabricated, the fiber diameter and mechanical strength of scaffolds with inhibitor were comparable with the non-drug scaffold. The SEM and MTT assay showed no toxic effect of ICG-001 to the proliferation of epithelial cells on the collagen/P(LLA-CL) scaffold with ICG-001. After treatment with culture medium released from the drug-delivering scaffold, the expression of Collagen type 1, 3 and fibronectin of fibroblasts could be inhibited significantly at the mRNA and protein levels. In the results of urethrography, urethral strictures and fistulas were found in the rabbits treated with non-ICG-001 delivering scaffolds, but all the rabbits treated with ICG-001-delivering scaffolds showed wide caliber in urethras. Histology results showed less collagen but more smooth muscle and thicker epithelium in urethras repaired with ICG-001 delivering scaffolds. Conclusion: After loading with the Wnt signal pathway inhibitor ICG-001, the Collagen/P(LLA-CL) scaffold could facilitate a decrease in the ECM deposition of fibroblasts. The ICG-001 delivering Collagen/P(LLA-CL) nanofibrous scaffold seeded with epithelial cells has the potential to be a promising substitute material for urethroplasty. Longer follow-up study in larger animals is needed in the future.
Progenitor cell niches in the human pancreatic duct system and associated pancreatic duct glands: an anatomical and immunophenotyping study.Friday, November 27, 2015
Carpino G, Renzi A, Cardinale V, Franchitto A, Onori P, Overi D, Rossi M, Berloco PB, Alvaro D, Reid LM, Gaudio E,
Journal of anatomy. 27-Nov-2015
Pancreatic duct glands (PDGs) are tubule-alveolar glands associated with the pancreatic duct system and can be considered the anatomical counterpart of peribiliary glands (PBGs) found within the biliary tree. Recently, we demonstrated that endodermal precursor niches exist fetally and postnatally and are composed functionally of stem cells and progenitors within PBGs and of committed progenitors within PDGs. Here we have characterized more extensively the anatomy of human PDGs as novel niches containing cells with multiple phenotypes of committed progenitors. Human pancreata (n = 15) were obtained from cadaveric adult donors. Specimens were processed for histology, immunohistochemistry and immunofluorescence. PDGs were found in the walls of larger pancreatic ducts (diameters > 300 μm) and constituted nearly 4% of the duct wall area. All of the cells identified were negative for nuclear expression of Oct4, a pluripotency gene, and so are presumably committed progenitors and not stem cells. In the main pancreatic duct and in large interlobular ducts, Sox9(+) cells represented 5-30% of the cells within PDGs and were located primarily at the bottom of PDGs, whereas rare and scattered Sox9(+) cells were present within the surface epithelium. The expression of PCNA, a marker of cell proliferation, paralleled the distribution of Sox9 expression. Sox9(+) PDG cells proved to be Pdx1(+) /Ngn3(+/-) /Oct4A(-) . Nearly 10% of PDG cells were positive for insulin or glucagon. Intercalated ducts contained Sox9(+) /Pdx1(+) /Ngn3(+) cells, a phenotype that is presumptive of committed endocrine progenitors. Some intercalated ducts appeared in continuity with clusters of insulin-positive cells organized in small pancreatic islet-like structures. In summary, PDGs represent niches of a population of Sox9(+) cells exhibiting a pattern of phenotypic traits implicating a radial axis of maturation from the bottoms of the PDGs to the surface of pancreatic ducts. Our results complete the anatomical background that links biliary and pancreatic tracts and could have important implications for the common patho-physiology of biliary tract and pancreas.
Generation of genome-edited mouse epiblast stem cells via a detour through ES cell-chimeras.Friday, November 27, 2015
Osteil P, Studdert J, Wilkie E, Fossat N, Tam PP,
Differentiation; research in biological diversity. 20-Nov-2015
Conventionally, mouse epiblast stem cells (EpiSCs) are derived directly from the epiblast or ectoderm germ layer of the post-implantation embryo. Self-renewing and multipotent EpiSC-like stem cells can also be derived by the conversion of embryonic stem cells (ESCs) via the provision of culture conditions that enable the maintenance of the EpiSCs. Here, we outline an experimental procedure for deriving EpiSCs from post-implantation chimeric embryos that are generated using genome-edited ESCs. This strategy enables the production of EpiSCs where (i) no genetically modified animals or ESCs are available, (ii) the impact of the genetic modification on post-implantation development, which may influence the property of the EpiSCs, is requisite knowledge for using the EpiSC for a specific investigation, and (iii) multiple editing of the genome is desirable to modify the biological attributes of the EpiSCs for studying, for example, the gene network activity on the trajectory of lineage differentiation and tissue morphogenesis.
A comprehensive study of novel microcapsules incorporating gliclazide and a permeation enhancing bile acid: hypoglycemic effect in an animal model of Type-1 diabetes.Thursday, November 26, 2015
Mathavan S, Chen-Tan N, Arfuso F, Al-Salami H,
Drug delivery. 26-Nov-2015
The incorporation of TCA into G-microcapsules resulted in functionally improved microcapsules with a positive effect on cell viability and glycemic control in Type-1 diabetic animals.
Membrane lipids as therapeutic targets for Parkinson's disease: a possible link between Lewy pathology and membrane lipids.Thursday, November 26, 2015
Kubo SI,
Expert opinion on therapeutic targets. 7-Sep-2015
Pathologically, Parkinson's disease (PD) is characterized by nigral cell loss and Lewy pathology in the remaining neurons. Whereas the motor symptoms of PD show a marked response to dopamine replacement therapy, many of the non-motor symptoms are resistant to treatment. This suggests that in addition to nigral cell loss, widespread Lewy pathology in the nervous system is associated with the manifestations of PD. Areas covered: Although the mechanism of Lewy body formation remains largely unknown, it is becoming clear that changes in the behavior of α-synuclein are critical in this process. α-Synuclein behaves differently depending on the lipid composition of membranes with which it interacts; therefore, one can postulate that the altered lipid composition of neuronal membranes may lead to Lewy pathology. The lipid composition of cellular membranes is consistently altered in the brains of patients with PD, and Lewy pathology is a common feature of several human lipidoses with mutations in enzymes that affect membrane lipids. This further supports the concept that alterations in the membrane lipids of neurons are central to Lewy pathology. Expert opinion: This concept provides a new platform to establish models for the development of novel treatments for PD.
Elevated α-synuclein caused by SNCA gene triplication impairs neuronal differentiation and maturation in Parkinson's patient-derived induced pluripotent stem cells.Thursday, November 26, 2015
Oliveira LM, Falomir-Lockhart LJ, Botelho MG, Lin KH, Wales P, Koch JC, Gerhardt E, Taschenberger H, Outeiro TF, Lingor P, Schüle B, Arndt-Jovin DJ, Jovin TM,
Cell death & disease. 7-9-2015
We have assessed the impact of α-synuclein overexpression on the differentiation potential and phenotypic signatures of two neural-committed induced pluripotent stem cell lines derived from a Parkinson's disease patient with a triplication of the human SNCA genomic locus. In parallel, comparative studies were performed on two control lines derived from healthy individuals and lines generated from the patient iPS-derived neuroprogenitor lines infected with a lentivirus incorporating a small hairpin RNA to knock down the SNCA mRNA. The SNCA triplication lines exhibited a reduced capacity to differentiate into dopaminergic or GABAergic neurons and decreased neurite outgrowth and lower neuronal activity compared with control cultures. This delayed maturation phenotype was confirmed by gene expression profiling, which revealed a significant reduction in mRNA for genes implicated in neuronal differentiation such as delta-like homolog 1 (DLK1), gamma-aminobutyric acid type B receptor subunit 2 (GABABR2), nuclear receptor related 1 protein (NURR1), G-protein-regulated inward-rectifier potassium channel 2 (GIRK-2) and tyrosine hydroxylase (TH). The differentiated patient cells also demonstrated increased autophagic flux when stressed with chloroquine. We conclude that a two-fold overexpression of α-synuclein caused by a triplication of the SNCA gene is sufficient to impair the differentiation of neuronal progenitor cells, a finding with implications for adult neurogenesis and Parkinson's disease progression, particularly in the context of bioenergetic dysfunction.
Elevated levels of ZAC1 disrupt neurogenesis and promote rapid in vivo reprogramming.Thursday, November 26, 2015
Rraklli V, Södersten E, Nyman U, Hagey DW, Holmberg J,
Stem cell research. 20-Nov-2015
The zinc finger transcription factor Zac1 is expressed in dividing progenitors of the nervous system with expression levels negatively controlled by genomic imprinting. To explore the consequences of elevated ZAC1 levels during neurogenesis we overexpressed it in the developing CNS. Increased levels of ZAC1 rapidly promoted upregulation of CDK inhibitors P57 and P27 followed by cell cycle exit. Surprisingly this was accompanied by stalled neuronal differentiation. Genome wide expression analysis of cortical cells overexpressing Zac1 revealed a decrease in neuronal gene expression and an increased expression of imprinted genes, factors regulating mesoderm formation as well as features of differentiated muscle. In addition, we observed a rapid induction of several genes regulating pluripotency. Taken together, our data suggests that expression levels of Zac1 need to be kept under strict control to avoid premature cell cycle exit, disrupted neurogenesis and aberrant expression of non-neuronal genes including pluripotency associated factors.
Inositide-dependent Signaling Pathways as New Therapeutic Targets in Myelodysplastic Syndromes.Thursday, November 26, 2015
Mongiorgi S, Finelli C, Yang YR, Clissa C, McCubrey JA, Billi AM, Manzoli L, Suh PG, Cocco L, Follo MY,
Expert opinion on therapeutic targets. 26-Nov-2015
Nuclear inositide signaling pathways specifically regulate cell proliferation and differentiation. Interestingly, the modulation of nuclear inositides in hematological malignancies can differentially affect erythropoiesis or myelopoiesis. This is particularly important in patients with Myelodysplastic Syndromes (MDS), who show both defective erythroid and myeloid differentiation, as well as an increased risk of evolution into Acute Myeloid Leukemia (AML). Areas covered: This review focuses on the structure and function of specific nuclear inositide enzymes, whose impairment could be linked with disease pathogenesis and cancer. The authors, stemming from literature and published data, discuss and describe the role of nuclear inositides, focusing on specific enzymes and demonstrating that targeting these molecules could be important to develop innovative therapeutic approaches, with particular reference to MDS treatment. Expert opinion: Demethylating therapy, alone or in combination with other drugs, is the most common and current therapy for MDS patients. Nuclear inositide signaling molecules have been demonstrated to be important in hematopoietic differentiation and are promising new targets for developing a personalized MDS therapy. Indeed, these enzymes can be ideal targets for drug design and their modulation can have several important downstream effects to regulate MDS pathogenesis and prevent MDS progression to AML.
Doxorubicin-loaded polypeptide nanorods based on electrostatic interactions for cancer therapy.Thursday, November 26, 2015
Zhang L, Zhang P, Zhao Q, Zhang Y, Cao L, Luan Y,
Journal of colloid and interface science. 6-Nov-2015
An amphiphilic anionic polypeptide, methoxypolyethylene glycol-poly (glutamic acid) (mPEG-PGA), was synthesized, characterized and evaluated as a nanocarrier for the cationic anticancer drug doxorubicin hydrochloride (DOX·HCl). The complex self-assembled into nanorods in aqueous solutions via electrostatic interactions and exhibited a superior drug loading content (50.8%) and drug loading efficiency (90.2%). The average major axis of the drug-loaded nanorods was approximately 300nm, as determined by transmission electron microscopy. An in vitro release assay showed that drug-loaded nanorods exhibited pH-sensitivity and sustained release. Haemolysis assays demonstrated that the polypeptide was haemocompatible, and the polypeptide drug carrier significantly reduced the haemolysis ratio of DOX·HCl. The pharmacokinetics study showed that DOX-loaded nanorods significantly prolonged the resident time in blood. An in vitro cytotoxicity study and cellular uptake assays demonstrated that the DOX-loaded nanorods resulted in higher cell proliferation inhibition and a higher level of tumour cell uptake in A549 cells than with free DOX·HCl. The prolonged circulation and enhanced antitumor efficacy of DOX-loaded nanorods shows promise for efficient cancer chemotherapy.
Therapeutic potential of mTOR inhibitors for targeting cancer stem cells.Thursday, November 26, 2015
Francipane MG, Lagasse E,
British journal of clinical pharmacology. 26-Nov-2015
The mammalian target of rapamycin (mTOR) pathway is aberrantly activated in many cancer types. As the intricate network of regulatory mechanisms controlling mTOR activity is uncovered, more-refined drugs are designed and tested in clinical trials. While first generation mTOR inhibitors have failed to show clinical efficiency due partly to the feedback relief of oncogenetic circuits, newly developed inhibitors show greater promise as anti-cancer agents. An effective drug must defeat the cancer stem cells (CSCs) while sparing the normal stem cells. Due to its opposing role on normal and malignant stem cells, mTOR lends itself very well as a therapeutic target. Indeed, a preferential inhibitory effect on CSCs has already been shown for some mTOR inhibitors. These results provide a compelling rationale for the clinical development of mTOR-targeted therapies. This article is protected by copyright. All rights reserved.
Effect of Surgical Intervention for Removal of Mandibular Third Molar on Periodontal Healing of Adjacent Mandibular Second Molar: A Systematic Review and Bayesian Network Meta-Analysis.Thursday, November 26, 2015
Barbato L, Kalemaj Z, Buti J, Baccini M, La Marca M, Duvina M, Tonelli P,
Journal of periodontology. 26-Nov-2015
At the best of our knowledge, the present review is the first one aiming to evaluate quantitatively and qualitatively the effect of different interventions on periodontal healing distal to second molar following extraction of third molar. GTR-based procedures with or without combined grafting therapies provide some adjunctive clinical benefit compared to standard non-regenerative/non-grafting procedures. However, the overall low quality of evidence suggests low degree of confidence and certainty in treatment effects. Evidence on variations of surgical M3M removal techniques based on flap design, type of suturing, and periodontal care of M2M is limited both qualitatively and quantitatively.
Cell Responses to Conditioned Media Produced by Patient-Matched Stem Cells Derived From Healthy and 'Inflamed' Periodontal Ligament Tissues.Thursday, November 26, 2015
Xia Y, Tang HN, Wu RX, Yu Y, Gao LN, Chen FM,
Journal of periodontology. 26-Nov-2015
The CMs of patient-matched H-PDLSCs and I-PDLSCs differed, and the impaired osteogenic differentiation of 'inflamed' stem cells had the potential to be rescued, at least partly, for therapeutic use via changing the cell culture microenvironment in vitro.
Pulmonary retention of adipose stromal cell following intravenous delivery is markedly altered in the presence of ARDS.Thursday, November 26, 2015
Lu H, Cook T, Poirier C, Merfeld-Clauss S, Petrache I, March KL, Bogatcheva NV,
Cell transplantation. 25-Nov-2015
Transplantation of mesenchymal stromal cells (MSC) has been shown to effectively prevent lung injury in several preclinical models of Acute Respiratory Distress Syndrome (ARDS). Since MSC therapy is tested in clinical trials for ARDS, there is an increased need to define the dynamics of cell trafficking and organ-specific accumulation. We examined how the presence of ARDS changes retention and organ-specific distribution of intravenously delivered MSC isolated from subcutaneous adipose tissue (ASC), cell therapy which was previously shown to ameliorate ARDS pathology. ARDS was triggered by lipopolysaccharide (LPS) aspiration, 4h after which 300,000 murine CRE-positive ASC were delivered intravenously. The distribution of ASC in lungs and other organs was assessed by real-time PCR of genomic DNA. As anticipated, the majority of delivered ASC accumulated in the lungs of both control and LPS-challenged mice, with minor amounts distributed to liver, kidney, spleen, heart, and brain. Interestingly, within 2h following ASC administration, LPS-challenged lung retained significantly lower levels of ASC compared to control lung (~7% vs. 15% of the original dose, respectively), whereas liver, kidney, spleen and brain of ARDS-affected animals retained significantly higher ASC compared to control animals. In contrast, 48h later, only LPS-challenged lungs continued to retain ASC (~3% of the original dose), whereas lungs of control animals and non-pulmonary organs in either control or ARDS mice had no detectable levels of ASC. Our data suggest that the pulmonary microenvironment during ARDS may lessen the pulmonary capillary occlusion by MSC immediately following cell delivery, while facilitating pulmonary retention of the cells.
Synergistic Effects of BMP9 and miR-548d-5p on Promoting Osteogenic Differentiation of Mesenchymal Stem Cells.Thursday, November 26, 2015
Zhang W, Zhang L, Zhou Y, Ji X, Liu J, Liu D, Yin P, Peng Y, Hao M, Zhang L, Tang P,
BioMed research international. 2015
Various stimulators have been reported to promote MSC osteogenic differentiation via different pathways such as bone morphogenetic protein 9 (BMP9) through influencing COX-2 and miR-548d-5p through targeting peroxisome proliferator-activated receptor-γ (PPARγ). Whether synergistic effects between BMP9 and miR-548d-5p existed in promoting osteogenesis from MSCs was unclear. In the study, the potential synergistic effects of BMP9 and miR-548d-5p on human MSC differentiation were investigated. Osteogenic differentiation of MSCs treated with BMP9 or miR-548d-5p was detected with multimodality of methods. The results demonstrated that BMP9 and miR-548d-5p significantly influenced COX-2 and PPARγ, respectively. BMP9 also influenced the expression of PPARγ, but no significant effect of miR-548d-5p on COX-2 was observed. When BMP9 and miR-548d-5p were combined, more potent effects on both COX-2 and PPARγ were observed than BMP9 or miR-548d-5p alone. Consistently, osteogenic analysis at different timepoints demonstrated that osteogenic genes, ALP activity, calcium deposition, OPN protein, and matrix mineralization were remarkably upregulated by BMP9/miR-548d-5p compared with BMP9 or miR-548d-5p alone, indicating the synergetic effects of BMP9 and miR-548d-5p on osteogenic differentiation of MSCs. Our study demonstrated that regulating different osteogenic regulators may be an effective strategy to promote bone tissue regeneration for bone defects.
Three-dimensional assessment of bystander effects of mesenchymal stem cells carrying a cytosine deaminase gene on glioma cells.Thursday, November 26, 2015
Jung JH, Kim AA, Chang DY, Park YR, Suh-Kim H, Kim SS,
American journal of cancer research. 01-11-2015
Stem cells carrying a suicide gene have emerged as therapeutic candidates for their cytotoxic bystander effects on neighboring cancers, while being non-toxic to other parts of the body. However, traditional cytotoxicity assays are unable to adequately assess the therapeutic effects of bystander cells. Here, we report a method to assess bystander effects of therapeutic stem cells against 3-dimensionally grown glioma cells in real time. U87 glioma cells were stably transduced to express a green fluorescence protein and co-cultivated with mesenchymal stem cells engineered to carry a bacterial cytosine deaminase gene (MSC/CD). Following addition of a 5-fluorocytine (5-FC) prodrug to the co-culture, fluorescence from U87 cells was obtained and analyzed in real time. Notably, the IC50 of 5-FC was higher when U87 cells were grown 3-dimensionally in soft agar medium for 3 weeks, as compared to those grown for one week in two-dimensional monolayer cultures. Additionally, more MSC/CD cells were required to maintain a similar level of efficacy. Since three-dimensional growth of glioma cells under our co-culture condition mimics the long-term expansion of cancer cells in vivo, our method can extend to an in vitro assay system to assess stem cell-mediated anti-cancer effects before advancing into preclinical animal studies.
LIN28B suppresses microRNA let-7b expression to promote CD44+/LIN28B+ human pancreatic cancer stem cell proliferation and invasion.Thursday, November 26, 2015
Shao Y, Zhang L, Cui L, Lou W, Wang D, Lu W, Jin D, Liu T,
American journal of cancer research. 15-8-2015
Although the highly proliferative, migratory, and multi-drug resistant phenotype of human pancreatic cancer stem cells (PCSCs) is well characterized, knowledge of their biological mechanisms is limited. We used CD44 and LIN28B as markers to screen, isolate, and enrich CSCs from human primary pancreatic cancer. Using flow cytometry, we identified a human primary pancreatic cancer cell (PCC) subpopulation expressing high levels of both CD44 and LIN28B. CD44+/LIN28B+ PCSCs expressed high levels of stemness marker genes and possessed higher migratory and invasive ability than CD44-/LIN28B- PCCs. CD44+/LIN28B+ PCSCs were more resistant to growth inhibition induced by the chemotherapeutic drugs cisplatin and gemcitabine hydrochloride, and readily established tumors in vivo in a relatively short time. Moreover, microarray analysis revealed significant differences between the cDNA expression patterns of CD44+/LIN28B+ PCSCs and CD44-/LIN28B- PCCs. Following siRNA interference of endogenous LIN28B gene expression in CD44+/LIN28B+ PCSCs, not only was their proliferation decreased, there was also cell cycle arrest due to suppression of cyclin D1 expression following the stimulation of miRNA let-7b expression. In conclusion, CD44+/LIN28B+ cells, which possess CSC characteristics, can be reliably sorted from human primary PCCs and represent a valuable model for studying cancer cell physiology and multi-drug resistance.
Beclin-1-independent autophagy mediates programmed cancer cell death through interplays with endoplasmic reticulum and/or mitochondria in colbat chloride-induced hypoxia.Thursday, November 26, 2015
Sun L, Liu N, Liu SS, Xia WY, Liu MY, Li LF, Gao JX,
American journal of cancer research. 15-8-2015
Autophagy has dual functions in cell survival and death. However, the effects of autophagy on cancer cell survival or death remain controversial. In this study, we show that Autophagy can mediate programmed cell death (PCD) of cancer cells in responding to cobalt chloride (CoCl2)-induced hypoxia in a Beclin-1-independent but autophagy protein 5 (ATG5)-dependent manner. Although ATG5 is not directly induced by CoCl2, its constitutive expression is essential for CoCl2-induced PCD. The ATG5-mediated autophagic PCD requires interplays with endoplasmic reticulum (ER) and/or mitochondria. In this process, ATG5 plays a central role in regulating ER stress protein CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) and mitochondrial protein second mitochondria derived activator of caspases (Smac). Two pathways for autophagic PCD in cancer cells responding to hypoxia have been identified: ATG5/CHOP/Smac pathway and ATG5/Smac pathway, which are probably dependent on the context of cell lines. The former is more potent than the latter for the induction of PCD at the early stage of hypoxia, although the ultimate efficiency of both pathways is comparable. In addition, both pathways may require ATG5-mediated conversion of LC3-I into LC3-II. Therefore, we have defined two autophagy-mediated pathways for the PCD of cancer cells in hypoxia, which are dependent on ATG5, interplayed with ER and mitochondria and tightly regulated by hypoxic status. The findings provide a new evidence that autophagy may inhibit tumor cell proliferation through trigger of PCD, facilitating the development of novel anti-cancer drugs.
Myeloproliferative Neoplasms in Children.Thursday, November 26, 2015
Hofmann I,
Journal of hematopathology. Sep-2015
Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders characterized by aberrant proliferation of one or more myeloid lineages often with increased immature cells in the peripheral blood. The three classical BCR-ABL-negative MPNs are: 1) polycythemia vera (PV), 2) essential thrombocythemia (ET), and 3) primary myelofibrosis (PMF), which are typically disorders of older adults and are exceedingly rare in children. The diagnostic criteria for MPNs remain largely defined by clinical, laboratory and histopathology assessments in adults, but they have been applied to the pediatric population. The discovery of the JAK2 V617F mutation, and more recently, MPL and CALR mutations, are major landmarks in the understanding of MPNs. Nevertheless, they rarely occur in children, posing a significant diagnostic challenge given the lack of an objective, clonal marker. Therefore, in pediatric patients, the diagnosis must rely heavily on clinical and laboratory factors, and exclusion of secondary disorders to make an accurate diagnosis of MPN. This review focuses on the clinical presentation, diagnostic work up, differential diagnosis, treatment and prognosis of the classical BCR-ABL-negative MPNs (PV, ET and PMF) in children and highlights key differences to the adult diseases. Particular attention will be given to pediatric PMF, as it is the only disorder of this group that is observed in infants and young children, and in many ways appears to be a unique entity compared to adult PMF.
Stimulating effect of graphene oxide on myogenesis of C2C12 myoblasts on RGD peptide-decorated PLGA nanofiber matrices.Thursday, November 26, 2015
Shin YC, Lee JH, Kim MJ, Hong SW, Kim B, Hyun JK, Choi YS, Park JC, Han DW,
Journal of biological engineering. 2-8-2015
In conclusion, these findings propose that the combination of RGD/PLGA nanofiber matrices and GO can be used as a promising strategy for skeletal tissue engineering and regeneration.
p53 siRNA - a therapeutic tool with significant implication in the modulation of apoptosis and angiogenic pathways.Thursday, November 26, 2015
Braicu O, Pileczki V, Braicu C, Achimas-Cadariu P, Irimie A, Berindan-Neagoe I,
Clujul medical (1957). 25-11-2015
RNAi may be a valuable technology in order to restore the normal cellular phenotype. The results in the current research may also have an important significance outside the context of cervical cancer, by using specific inhibitors for p53 for increasing the therapeutic response in a wide range of tumoral pathology.
Iron, inflammation and invasion of cancer cells.Thursday, November 26, 2015
Fischer-Fodor E, Miklasova N, Berindan-Neagoe I, Saha B,
Clujul medical (1957). 01-7-2015
Chronic inflammation is associated with the metastasis of tumor cells evolving from a benign tumor to disseminating cancer. Such a metastatic progression is fostered by the angiogenesis propelled by various mediators interacting at the site of tumor growth. Angiogenesis causes two major changes that are assisted by altered glycosylation and neo-antigen presentation by the cancer cells. The angiogenesis-promoted pathological changes include enhanced inflammation and degradation of tissue matrices releasing tumor cells from the site of its origin. The degraded tumor cells release the neo-antigens resulting from altered glycosylation. Presentation of neo-antigens to T cells escalates metastasis and inflammation. Inflammasome activation and inflammation in several infections are regulated by iron. Based on the discrete reports, we propose a link between iron, inflammation, angiogenesis and tumor growth. Knowing the link better may help us formulate a novel strategy for cancer immunotherapy.
Stem cells - biological update and cell therapy progress.Thursday, November 26, 2015
Girlovanu M, Susman S, Soritau O, Rus-Ciuca D, Melincovici C, Constantin AM, Mihu CM,
Clujul medical (1957). 01-7-2015
In recent years, the advances in stem cell research have suggested that the human body may have a higher plasticity than it was originally expected. Until now, four categories of stem cells were isolated and cultured in vivo: embryonic stem cells, fetal stem cells, adult stem cells and induced pluripotent stem cells (hiPSCs). Although multiple studies were published, several issues concerning the stem cells are still debated, such as: the molecular mechanisms of differentiation, the methods to prevent teratoma formation or the ethical and religious issues regarding especially the embryonic stem cell research. The direct differentiation of stem cells into specialized cells: cardiac myocytes, neural cells, pancreatic islets cells, may represent an option in treating incurable diseases such as: neurodegenerative diseases, type I diabetes, hematologic or cardiac diseases. Nevertheless, stem cell-based therapies, based on stem cell transplantation, remain mainly at the experimental stages and their major limitation is the development of teratoma and cancer after transplantation. The induced pluripotent stem cells (hiPSCs) represent a prime candidate for future cell therapy research because of their significant self-renewal and differentiation potential and the lack of ethical issues. This article presents an overview of the biological advances in the study of stem cells and the current progress made in the field of regenerative medicine.
VEGF involvement in psoriasis.Thursday, November 26, 2015
Marina ME, Roman II, Constantin AM, Mihu CM, Tătaru AD,
Clujul medical (1957). 01-7-2015
Vascular endothelial growth factor (VEGF) is a key growth factor, regulating the neovascularization, during embryogenesis, skeletal growth, reproductive functions and pathological processes. The VEGF receptors (VEGFR) are present in endothelial cells and other cell types, such as vascular smooth muscle cells, hematopoietic stem cells, monocytes, neurons, macrophages, and platelets. Angiogenesis is initiated by the activation of vascular endothelial cells through several factors. The excess dermal vascularity and VEGF production are markers of psoriasis. The pathological role of VEGF/VEGFR signaling during the psoriasis onset and evolution makes it a promising target for the treatment of psoriasis. Antibodies and other types of molecules targeting the VEGF pathway are currently evaluated in arresting the evolution of psoriasis.
Management of knee osteoarthritis by combined stromal vascular fraction cell therapy, platelet-rich plasma, and musculoskeletal exercises: a case series.Thursday, November 26, 2015
Gibbs N, Diamond R, Sekyere EO, Thomas WD,
Journal of pain research. 01-7-2015
This case series indicates that improved outcomes may be obtained when autologous stromal vascular fraction (StroMed) cell therapy is combined with traditional exercise practices and PRP for osteoarthritis. Of the seven joints treated: all patients' scores of pain improved to >96; and quality of life scores to >93. Functional performance measures of mobility returned to normal. This simple treatment appears to be extremely effective for osteoarthritis disorders that have no drug treatment to halt disease progression.
Cancer Stem and Progenitor-Like Cells as Pharmacological Targets in Breast Cancer Treatment.Thursday, November 26, 2015
de Souza VB, Schenka AA,
Breast cancer : basic and clinical research. 09-11-2015
The present review is focused on the current role of neoplastic stem and progenitor-like cells as primary targets in the pharmacotherapy of cancer as well as in the development of new anticancer drugs. We begin by summarizing the main characteristics of these tumor-initiating cells and key concepts that support their participation in therapeutic failure. In particular, we discuss the differences between the major carcinogenesis models (ie, clonal evolution vs cancer stem cell (CSC) model) with emphasis on breast cancer (given its importance to the study of CSCs) and their implications for the development of new treatment strategies. In addition, we describe the main ways to target these cells, including the main signaling pathways that are more activated or altered in CSCs. Finally, we provide a comprehensive compilation of the most recently tested drugs.
Nanoshell-mediated photothermal therapy can enhance chemotherapy in inflammatory breast cancer cells.Thursday, November 26, 2015
Fay BL, Melamed JR, Day ES,
International journal of nanomedicine. 12-11-2015
Nanoshell-mediated photothermal therapy (PTT) is currently being investigated as a standalone therapy for the treatment of cancer. The cellular effects of PTT include loss of membrane integrity, so we hypothesized that nanoshell-mediated PTT could potentiate the cytotoxicity of chemotherapy by improving drug accumulation in cancer cells. In this work, we validated our hypothesis using doxorubicin as a model drug and SUM149 inflammatory breast cancer cells as a model cancer subtype. In initial studies, SUM149 cells were exposed to nano-shells and near-infrared light and then stained with ethidium homodimer-1, which is excluded from cells with an intact plasma membrane. The results confirmed that nanoshell-mediated PTT could increase membrane permeability in SUM149 cells. In complementary experiments, SUM149 cells treated with nanoshells, near-infrared light, or a combination of the two to yield low-dose PTT were exposed to fluorescent rhodamine 123. Analyzing rhodamine 123 fluorescence in cells via flow cytometry confirmed that increased membrane permeability caused by PTT could enhance drug accumulation in cells. This was validated using fluorescence microscopy to assess intracellular distribution of doxorubicin. In succeeding experiments, SUM149 cells were exposed to subtherapeutic levels of doxorubicin, low-dose PTT, or a combination of the two treatments to determine whether the additional drug uptake induced by PTT is sufficient to enhance cell death. Analysis revealed minimal loss of viability relative to controls in cells exposed to subtherapeutic levels of doxorubicin, 15% loss of viability in cells exposed to low-dose PTT, and 35% loss of viability in cells exposed to combination therapy. These data indicate that nanoshell-mediated PTT is a viable strategy to potentiate the effects of chemotherapy and warrant further investigation of this approach using other drugs and cancer subtypes.
Metabolic Serum Profiles for Patients Receiving Allogeneic Stem Cell Transplantation: The Pretransplant Profile Differs for Patients with and without Posttransplant Capillary Leak Syndrome.Thursday, November 26, 2015
Reikvam H, Grønningsæter IS, Ahmed AB, Hatfield K, Bruserud Ø,
Disease markers. 06-11-2015
Allogeneic stem cell transplantation is commonly used in the treatment of younger patients with severe hematological diseases, and endothelial cells seem to be important for the development of several posttransplant complications. Capillary leak syndrome is a common early posttransplant complication where endothelial cell dysfunction probably contributes to the pathogenesis. In the present study we investigated whether the pretreatment serum metabolic profile reflects a risk of posttransplant capillary leak syndrome. We investigated the pretransplant serum levels of 766 metabolites for 80 consecutive allotransplant recipients. Patients with later capillary leak syndrome showed increased pretherapy levels of metabolites associated with endothelial dysfunction (homocitrulline, adenosine) altered renal regulation of fluid and/or electrolyte balance (betaine, methoxytyramine, and taurine) and altered vascular function (cytidine, adenosine, and methoxytyramine). Additional bioinformatical analyses showed that capillary leak syndrome was also associated with altered purine/pyrimidine metabolism (i.e., metabolites involved in vascular regulation and endothelial functions), aminoglycosylation (possibly important for endothelial cell functions), and eicosanoid metabolism (also involved in vascular regulation). Our observations are consistent with the hypothesis that the pretransplant metabolic status can be a marker for posttransplant abnormal fluid and/or electrolyte balance.
A Smaug2-Based Translational Repression Complex Determines the Balance between Precursor Maintenance versus Differentiation during Mammalian Neurogenesis.Thursday, November 26, 2015
Amadei G, Zander MA, Yang G, Dumelie JG, Vessey JP, Lipshitz HD, Smibert CA, Kaplan DR, Miller FD,
The Journal of neuroscience : the official journal of the Society for Neuroscience. 25-Nov-2015
The mechanisms instructing neural stem cells to generate the appropriate progeny are still poorly understood. Here, we show that the RNA-binding proteins Smaug2 and Nanos1 are critical regulators of this balance and provide evidence supporting the idea that neural precursors are transcriptionally primed to generate neurons but translational regulation maintains these precursors in a stem cell state until the appropriate developmental time.
Human Umbilical Tissue-Derived Cells Promote Synapse Formation and Neurite Outgrowth via Thrombospondin Family Proteins.Thursday, November 26, 2015
Koh S, Kim N, Yin HH, Harris IR, Dejneka NS, Eroglu C,
The Journal of neuroscience : the official journal of the Society for Neuroscience. 25-Nov-2015
Human umbilical tissue-derived cells (hUTC) are currently under clinical investigation for the treatment of geographic atrophy secondary to age-related macular degeneration. These cells show great promise for the treatment of neurological disorders; however, the therapeutic effects of these cells on CNS neurons are not fully understood. Here we provide compelling evidence that hUTCs secrete multiple factors that work synergistically to enhance synapse formation and function, and support neuronal growth and survival. Moreover, we identified thrombospondins (TSPs) as the hUTC-secreted factors that mediate the synaptogenic and growth-promoting functions of these cells. Our findings highlight novel paracrine effects of hUTC on CNS neuron health and connectivity and begin to unravel potential therapeutic mechanisms by which these cells elicit their effects.
Mitochonic Acid 5 Binds Mitochondria and Ameliorates Renal Tubular and Cardiac Myocyte Damage.Thursday, November 26, 2015
Suzuki T, Yamaguchi H, Kikusato M, Hashizume O, Nagatoishi S, Matsuo A, Sato T, Kudo T, Matsuhashi T, Murayama K, Ohba Y, Watanabe S, Kanno SI, Minaki D, Saigusa D, Shinbo H, Mori N, Yuri A, Yokoro M, Mishima E, Shima H, Akiyama Y, Takeuchi Y, Kikuchi K, Toyohara T, Suzuki C, Ichimura T, Anzai JI, Kohzuki M, Mano N, Kure S, Yanagisawa T, Tomioka Y, Tohyomizu M, Tsumoto K, Nakada K, Bonventre JV, Ito S, Osaka H, Hayashi KI, Abe T,
Journal of the American Society of Nephrology : JASN. 25-Nov-2015
Mitochondrial dysfunction causes increased oxidative stress and depletion of ATP, which are involved in the etiology of a variety of renal diseases, such as CKD, AKI, and steroid-resistant nephrotic syndrome. Antioxidant therapies are being investigated, but clinical outcomes have yet to be determined. Recently, we reported that a newly synthesized indole derivative, mitochonic acid 5 (MA-5), increases cellular ATP level and survival of fibroblasts from patients with mitochondrial disease. MA-5 modulates mitochondrial ATP synthesis independently of oxidative phosphorylation and the electron transport chain. Here, we further investigated the mechanism of action for MA-5. Administration of MA-5 to an ischemia-reperfusion injury model and a cisplatin-induced nephropathy model improved renal function. In in vitro bioenergetic studies, MA-5 facilitated ATP production and reduced the level of mitochondrial reactive oxygen species (ROS) without affecting activity of mitochondrial complexes I-IV. Additional assays revealed that MA-5 targets the mitochondrial protein mitofilin at the crista junction of the inner membrane. In Hep3B cells, overexpression of mitofilin increased the basal ATP level, and treatment with MA-5 amplified this effect. In a unique mitochondrial disease model (Mitomice with mitochondrial DNA deletion that mimics typical human mitochondrial disease phenotype), MA-5 improved the reduced cardiac and renal mitochondrial respiration and seemed to prolong survival, although statistical analysis of survival times could not be conducted. These results suggest that MA-5 functions in a manner differing from that of antioxidant therapy and could be a novel therapeutic drug for the treatment of cardiac and renal diseases associated with mitochondrial dysfunction.
Using Mathematical Modeling to Design Effective Regenerative Medicine Strategies for Orthopaedics.Thursday, November 26, 2015
Robertson DD, Sharma GB, Boyan BD,
The Journal of the American Academy of Orthopaedic Surgeons. 25-Nov-2015
Agonists of the TRAIL death receptor DR5 sensitize intestinal stem cells to chemotherapy-induced cell death and trigger gastrointestinal toxicity.Thursday, November 26, 2015
Finnberg NK, Gokare P, Navaraj A, Lang Kuhs KA, Cerniglia GJ, Yagita H, Takeda K, Motoyama N, El-Deiry WS,
Cancer research. 25-Nov-2015
The combination of TRAIL death receptor agonists and radiochemotherapy to treat advanced cancers continues to be investigated in clinical trials. We previously showed that normal cells with a functional DNA damage response (DDR) upregulate the expression of death inducing receptor DR5/TRAILR2/TNFRSF10B in a p53-dependent manner that sensitizes them to treatment with DR5 agonists. However, it is unclear if targeting DR5 selectively sensitizes cancer cells to agonist treatment following exposure to DNA-damaging chemotherapy, and to what extent normal tissues are targeted. Here, we show that the combined administration of the DR5 agonistic monoclonal antibody (mAb) and chemotherapy to wildtype mice triggered synergistic gastrointestinal toxicities (GIT) that were associated with the death of Lgr5+ crypt base columnar (CBC) stem cells in a p53- and DR5-dependent manner. Furthermore, we confirmed that normal human epithelial cells treated with the human DR5-agonistic mAb and chemotherapeutic agents were also greatly sensitized to cell death. Interestingly, our data also indicated that genetic or pharmacologic targeting of Chk2 may counteract GIT without negatively impacting the antitumor responses of combined DR5 agonist/chemotherapy treatment, further linking the DDR to TRAIL death receptor signaling in normal cells. In conclusion, the combination of DR5-targeting agonistic mAbs with DNA damaging chemotherapy may pose a risk of developing toxicity-induced conditions, and the effects of mAb-based strategies on the dose-limiting toxicity of chemotherapy must be considered when establishing new combination therapies.
Cancer stem cells in hepatocellular carcinoma - an immunohistochemical study with histopathological association.Thursday, November 26, 2015
Matthai SM, Ramakrishna B,
The Indian journal of medical research. Oct-2015
The LCSC marker EpCAM was expressed in less than half of HCC, was independent of HBV aetiology, and was strongly associated with clinical and histological features of aggressive tumour behaviour. Positive staining for CK19 suggests a possible LPC origin of the EpCAM positive HCCs.
Cancer stem cells in hepatocellular carcinomas.Thursday, November 26, 2015
Das P, Gupta SD,
The Indian journal of medical research. Oct-2015
The DNA Ligase IV Syndrome R278H Mutation Impairs B Lymphopoiesis via Error-Prone Nonhomologous End-Joining.Thursday, November 26, 2015
Park J, Welner RS, Chan MY, Troppito L, Staber PB, Tenen DG, Yan CT,
Journal of immunology (Baltimore, Md. : 1950). 25-Nov-2015
Hypomorphic mutations in the nonhomologous end-joining (NHEJ) DNA repair protein DNA ligase IV (LIG4) lead to immunodeficiency with varying severity. In this study, using a murine knock-in model, we investigated the mechanisms underlying abnormalities in class switch recombination (CSR) associated with the human homozygous Lig4 R278H mutation. Previously, we found that despite the near absence of Lig4 end-ligation activity and severely reduced mature B cell numbers, Lig4(R278H/R278H) (Lig4(R/R)) mice exhibit only a partial CSR block, producing near normal IgG1 and IgE but substantially reduced IgG3, IgG2b, and IgA serum levels. In this study, to address the cause of these abnormalities, we assayed CSR in Lig4(R/R) B cells generated via preassembled IgH and IgK V region exons (HL). This revealed that Lig4(R278H) protein levels while intact exhibited a higher turnover rate during activation of switching to IgG3 and IgG2b, as well as delays in CSR kinetics associated with defective proliferation during activation of switching to IgG1 and IgE. Activated Lig4(R/R)HL B cells consistently accumulated high frequencies of activation-induced cytidine deaminase-dependent IgH locus chromosomal breaks and translocations and were more prone to apoptosis, effects that appeared to be p53-independent, as p53 deficiency did not markedly influence these events. Importantly, NHEJ instead of alternative end-joining (A-EJ) was revealed as the predominant mechanism catalyzing robust CSR. Defective CSR was linked to failed NHEJ and residual A-EJ access to unrepaired double-strand breaks. These data firmly demonstrate that Lig4(R278H) activity renders NHEJ to be more error-prone, and they predict increased error-prone NHEJ activity and A-EJ suppression as the cause of the defective B lymphopoiesis in Lig4 patients.
Source: NCBI - Disclaimer and Copyright notice
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