Nlrp6 protects from corticosterone-induced NSPC ferroptosis by modulating RIG-1/MAVS-mediated mitophagy

Hippocampal neural stem/progenitor cells (NSPCs) are highly vulnerable to different stress stimuli, resulting in adult neurogenesis decline and eventual cognitive defects. Our previous study demonstrated that NOD-like receptor family pyrin domain-containing 6 (Nlrp6) highly expressed in NSPCs played a critical role in sustaining hippocampal neurogenesis to resist stress-induced depression, but the underlying mechnistms are still unclear. Here, we found that Nlrp6 depletion led to cognitive defects and hippocampal NSPC loss in mice. RNAsequencing analysis of the primary NSPCs revealed that Nlrp6 deficiency altered gene expression profiles of mitochondrial energy generation and ferroptotic process. Upon siNlrp6 transfection, as well as corticosterone (CORT) exposure, downregulation of Nlrp6 suppressed retinoic acid-inducible gene I (RIG-1)/mitochondrial antiviral signaling proteins (MAVS)-mediated autophagy, but drove NSPC ferroptotic death. More interesting, short chain fatty acids (SCFAs) upregulated Nlrp6 expression and promoted RIG-1/MAVS-mediated mitophagy, preventing CORT-induced NSPC ferroptosis. Our study further demonstrates that Nlrp6 should be a sensor for RIG-1/MAVS-mediated mitophagy and play a critical role in maintain mitochondrial homeostasis of hippocampal NSPCs. These results suggests that Nlrp6 should be a potential drug target to combat neurodegenerative diseases relative with chronic stress.