Autophagy gene FIP200 in neural progenitors non-cell autonomously controls differentiation by regulating microglia

Recent studies have shown important roles for autophagy genes in the regulation of different tissue stem cells, including neural stem/progenitor cells (NSCs). However, little is known about whether autophagy can regulate NSCs through cell-extrinsic mechanisms. Here, we show that deletion of an essential autophagy gene, FIP200, in NSCs increased expression of Ccl5 and Cxcl10 in a p53-independent manner, mediating increased infiltration of microglia into the subventricular zone of both FIP200hGFAP conditional knockout (cKO) and FIP200;p53hGFAP 2cKO mice. The microglia exhibited an activated M1 phenotype consistent with their potential to inhibit differentiation of FIP200-null NSCs. Blocking either microglia infiltration or activation rescued the deficient differentiation of FIP200-null NSCs from FIP200;p53hGFAP 2cKO mice. Lastly, we showed that increased chemokine expression in FIP200-null NSCs was induced by abnormal p62 aggregate formation and activation of NF-κB signaling. Our results suggest that autophagy plays a crucial role in regulating neurogenesis and restricting local immune response in postnatal NSCs through non-cell autonomous mechanisms.