Emerging Technologies in Neurodegeneration Research

Emerging Technologies in Research In vitro models that accurately mimic a biologically healthy/diseased state are key to capturing the complexities of neurodegenerative diseases. Neuroscience has traditionally depended on primary neurons and neuron-like cell lines, but these approaches do not fully represent the human brain, limiting their translational value. Patient-derived stem cells and more advanced 3D in vitro models can mimic the brain more closely. A summary of some of the advanced cell models currently being employed in neurodegenerative disease research is outlined below. Modeling NEURODEGENERATION Advances in IMAGING AND ANALYSIS Label-free analysis Various cell biology techniques are used to study neurodegeneration in vitro including flow cytometry and high-content imaging. The preparation and labeling required in traditional cell biology techniques can cause significant disruption to the cellular environment, a limitation that is overcome with the emergence of label-free technologies. These technologies have been applied to applications including the study of protein misfolding and aggregation that play a central role in the pathogenesis of various neurodegenerative diseases such as Huntington’s disease. Benefits of label-free analysis  The ligand can retain its native conformation and biological activity. Labelfree analysis therefore provides more physiologically relevant insights.  Avoiding labeling agents eliminates the risk of unwanted background signals that can occur when labels bind non-specifically.  Label-free technology enables real-time interaction analysis that is not possible using conventional methods that provide only end-point results. These include kinetic and affinity analysis and evaluation of binding specificity. Live cell imaging Traditional, endpoint cell-based experiments such as flow cytometry often fail to track subtle yet critical changes in cell behavior over time. Real-time, live-cell analysis can overcome this and enable the capture of biological changes as they occur by repeatedly acquiring images of the same cells over long periods. Live cell imaging is useful when investigating live neuron dynamics, as imaging fixed samples does not cover the dynamic events that occur during the development and regeneration of the nervous system. Organs-on-chips Organ-on-a-chip systems contain engineered or natural miniature tissues grown inside microfluidic chips. They are designed to offer precise spatiotemporal control over cell microenvironments and can recreate organ-level structure as well as provide relevant mechanical cues. Researchers have developed an organ-on-a-chip system that replicates interactions between the brain, liver, and colon. They modeled gut microbe influences on healthy brain tissue and PD patients’ tissue samples, finding that short-chain fatty acids produced by microbes can further exacerbate certain pathologies related to PD. Human iPSCs Human induced pluripotent stem cells (iPSCs) are a promising cell type for developing more reliable neurological in vitro models. iPSCs can be derived directly from adult tissue and reprogrammed to differentiate into various cell types including human neurons. As humanderived iPSCs possess the donor's genetic information, they provide access to patientspecific models and as such a more accurate way to evaluate individual responses to treatments. Researchers recently developed a model that rapidly converts iPSCs to brain cells characteristic of Parkinson’s disease (PD) to create personalized stem cell models, providing novel opportunities to test treatments. Organoids Organoids are 3D cultures containing several types of self-organizing cells that perform, as a minimum, one function of the organ they are mimicking. 3D brain organoids can be generated from iPSCs and are useful for studying the pathogenic characteristics of neurodegenerative illnesses. To improve these models structurally and functionally, recent efforts have aimed to combine organoids to produce larger assembloids. Researchers have described the construction of human blood-brain barrier (BBB) assembloids from brain and blood vessel organoids derived from human pluripotent stem cells. Neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET) allow for non-invasive visualization of the brain's structure and function. Recent advances in these technologies, such as the development of ultra-high-resolution MRI scanners, have transformed the ability to study the anatomical, microstructural and physiological changes occurring during neurodegeneration in the brain in vivo. Neurodegeneration refers to the progressive loss of neuron structure and function that leads to eventual cell death. It is a key feature of neurodegenerative diseases such as Alzheimer's and Parkinson's disease. The complexity of neural tissue and its location has made researching and developing therapies for neurodegenerative diseases difficult. However, advances in cell models and imaging have now greatly simplified its study. Somatic cells iPSC Embryo Embryonic stem cells iPSCs Floating spheroid Floating spheroid Cancer cells Somatic stem cells 3D culture Media pump 2 Media pump 1 Cell media type 1 Cell media type 2 Transepithelial electrical resistance sensor Cell layer Incubator Microscope Soluble metabolite Metabolism Cell organoid Extracellular matrix Organoid culture Tumor or cancer tissue Healthy tissue Human Differentiation Neuron Cardiomyocyte Hematopoietic stem cell Reprogramming + Reprogramming agents Culture conditions are changed to stimulate cells to differentiate into different cell types The next big challenge in neurodegeneration is likely to involve the management and analysis of the large datasets generated from analysis which can include months and even years' worth of data. Here, artificial intelligence could help, taking the strain off researchers to help process vast, complex datasets to reveal new insights into neuroscience and disease. Sponsored by GETTING THE MOST OUT OF CELL MODELS STREAMLINING DATA ANALYSIS VISUALIZING THE BRAIN IN VIVO Illustration of the process for reprogramming somatic cells to iPSCs and subsequent differentiation. Schematic representation of the protocol for organoid generation A model organ-on-a-chip system. This system studies two cell substrates – a cell layer and an organoid.