Nat Neurosci: research reveals the molecular mechanism of stroke

February 13, 2020 news / Bio Valley bio on / -- macrophages as part of the innate immune system, are essential for brain development and function Scientists from Jena University Hospital, Bonn University and memorial Sloan Caitlin cancer center in New York have used a novel method to successfully "see" macrophages formed in bone marrow Using the technique, researchers were able to observe large numbers of migrating macrophages in the blood of mice shortly after a stroke, which began attacking dead brain cells and adjacent healthy brain tissue The results were published recently in nature neuroscience (image source: www Pixabay Com) macrophages are part of our innate immune system and are present in various tissues of our body In the brain, these macrophages are called microglia, which play an important role in normal brain development and function In the process of inflammation (such as stroke, brain infection, multiple sclerosis or Alzheimer's disease), macrophages in other parts begin to gather, migrate and play a role Due to the inability to accurately identify macrophages in different parts, the origin of inflammatory macrophages has not been revealed To this end, Professor Frederic geissmann and his collaborators from Sloan Caitlin Memorial cancer center constructed a mouse model to induce the expression of CXCR4 gene All immune cells derived from bone marrow stem cells in the blood circulation system can produce fluorescence signals through special drug induction "The trick of our model is that only immune cells from the bone marrow system fluoresce, whereas microglia in the brain are not labeled," explains pharmacologist stump Therefore, it is easy to distinguish the migrated "foreign" immune cells from the intrinsic microglia in the brain by color The researchers were able to show that in healthy mice, there was almost no deposition of macrophages from bone marrow stem cells in the brain In addition, researchers found that shortly after a stroke, large amounts of macrophages migrating from the blood began attacking dead and nearby healthy brain tissue Next, the researchers inactivated the function of the CXCR4 gene When CXCR4 is not functioning, stroke initially attracts fewer macrophages into the brain, the researchers found In the next few days, macrophages that have already migrated to the brain will not migrate completely to the dead brain tissue In addition, the lack of CXCR4 receptor in apoplectic mice led to the increase of tissue damage and the deterioration of the overall condition of mice In conclusion, in this study, the authors have successfully used genetic tools to prove that CXCR4 receptor is a key part of immune response, which can be used by macrophages from bone marrow to protect damaged brain "The more we know about the dynamics of CXCR4 activation during stroke, the better we will be able to treat our patients in the future," said Professor stump Source of information: stroke: macrophases migrate from the blood source: Yves Werner et al, CXCR4 distinguishes HSC-derived months from microglia and reeveals monthly response to experimental stroke, Nature Neuroscience (2020) Doi: 10.1038/s41593-020-0585-y