Microorganisms are sometimes considered as dirty organisms that threaten our health, decay food and cause inconvenience in our daily life. However, they play a critical role in making nutrients by metabolizing food, allowing all living creatures to live on. There are 2,000 kinds of microorganisms and several hundred trillion in figures living in our bodies. Most of these microorganisms live in digestive tracts but their effect is shown in our entire body. Recently, the research team of POSTECH discovered how the microbiota transmits signals to the entire body and control hematopoiesis in the bone marrow.
Professor Seung-Woo Lee, Research Professor Yunji Park, Master/Ph.D. integrated program students, Seungwon Lee and Hyekang Kim of Division of Integrative Biosciences and Biotechnology from POSTECH described the mechanism how microbiota signals are sent to different organs. They also utilized imaging research to determine if CX3CR+ mononuclear cells contact hemopoietic progenitors.
Recent research concluded that microbiota control biological phenomena not only in digestive tracts but also in the lungs, liver, brain, bone marrow and other organs. However, none of them were able to define a mechanism for relaying microbiota signals to entire body or for producing immune cells by receiving microbiota signals.
Professor Lee and his research team focused on the fact that the microbiota regulates the immune system of our body by controlling hematopoiesis in the bone marrow to produce white blood cells. In this process, the team discovered that the microbiota signal including bacterial DNA is transferred to the bone marrow through the bloodstream and CX3CR1+ mononuclear cells in the bone marrow recognize this signal.
They explained that when CX3CR1+ mononuclear cells recognize microbiota signals, they release signal substances called cytokines which control and stimulate body’s defense system through the signal transduction. They also explained that cytokines control the number of hematopoietic progenitors or stimulate differentiation into myeloid lineages to make blood cells.
Furthermore, they verified that CX3CR1+ mononuclear cells contact hematopoietic progenitors at the perivascular region and receive microbiota signals.
They discovered the hematopoiesis control mechanism which is controlled by cytokines produced when CX3CR1+ mononuclear cells recognize microbiota signals transferred to the bone marrow.
Professor Seung-Woo Lee commented, “For the first time, our research describes the mechanism that had not been explained how microbiota regulate not only digestive tracts but also an entire body response. It might be possible to apply this study to control immune response in other parts of a body or to treat cancer and inflammatory disease via microbiota signal pathway.”
Lee et al. (2019) Bone marrow CX3CR1+ mononuclear cells relay a systemic microbiota signal to control hematopoietic progenitors in mice. Blood. DOI: https://doi.org/10.1182/blood.2019000495
This article has been republished from the following materials. Note: material may have been edited for length and content. For further information, please contact the cited source.