Microglia constitute a highly specialized network of tissue resident immune cells that is important for the control of tissue homeostasis and the resolution of virtually all diseases of the central nervous system (CNS). However, how this dissemination  is established and maintained in vivo and its kinetics of these processes are poorly understood. Here we established a new multicolor fluorescence fate mapping system to monitor microglia dynamics during steady state  and disease. Our findings that microglia establish a stable network over time albeit with regional differences and remarkably high turnover rates challenge their postulated longevity. Microglia self-renewal constitutes a random process  without evidence of defined progenitor cells. Under pathological conditions this randomness shifts to clonal microglia expansion that is finally resolved by both cell apoptosis and egression for re-establishment of the stable microglia network. Our data reveal new insights on how microglia ensure their complex distribution throughout the healthy and diseased CNS . SOURCE: Ori Staszewski (ori.staszewski@uniklinik-freiburg.de) -  University Medical Center Freiburg

Pluto Bioinformatics

GSE79252: Microglia self-renewal comprises context-dependent random or clonal expansion.