Bulk RNA-seq of FACS sorted astrocytes upon microglial depletion

As the professional phagocyte in the central nervous system (CNS), microglia are the primary scavenger removing cell corpses. The failure of microglia in debris clearance influences the normal CNS function. Meanwhile, microglia undergo turnover during the whole lifespan. If dead microglia are not timely removed, accumulated corpses may influence the CNS function. The microglial corpse clearance is hereby crucial for CNS homeostasis. However, the underlying mechanism remains obscure. In this study, we investigated how microglial corpses are removed. We found that microglial corpses are mainly phagocytosed by astrocytes, mediated by C4b opsonization. Then engulfed microglial fragments are degraded in astrocytes via the RUBICON-dependent LC3-associated phagocytosis (LAP), a form of non-canonical autophagy. The interference of the C4b-mediated engulfment and its subsequent LAP disrupt the microglial debris removal and degradation, respectively. Together, we elucidated cellular and molecular mechanisms of microglial debris removal, extending the knowledge on how the CNS homeostasis is maintained. Tamoxifen induced adult ALDH1L1-CreER::Ai14 mice. A group was fed PLX5622-formulated chow diet while the other group was fed control diet (CD)