Mettl3‐mediated m6A modification of Lrp2 facilitates neurogenesis through Ythdc2 and elicits antidepressant‐like effects

Abstract N 6 ‐methyladenosine (m 6 A) is the most abundant mRNA modification affecting diverse biological processes. However, the functions and precise mechanisms of m 6 A signaling in adult hippocampal neurogenesis and neurogenesis‐related depression remain largely enigmatic. We found that depletion of Mettl3 or Mettl14 in neural stem cells (NSCs) dramatically reduced m 6 A abundance, proliferation, and neuronal genesis, coupled with enhanced glial differentiation. Conversely, overexpressing Mettl3 promoted proliferation and neuronal differentiation. Mechanistically, the m 6 A modification of Lrp2 mRNA by Mettl3 enhanced its stability and translation efficiency relying on the reader protein Ythdc2, which in turn promoted neurogenesis. Importantly, mice lacking Mettl3 manifested reduced hippocampal neurogenesis, which could contribute to spatial memory decline, and depression‐like behaviors. We found that these defective behaviors were notably reversed by Lrp2 overexpression. Moreover, Mettl3 overexpression in the hippocampus of depressive mice rescues behavioral defects. Our findings uncover the biological role of m 6 A modification in Lrp2‐mediated neurogenesis via m 6 A‐binding protein Ythdc2, and propose a rationale that targeting Mettl3‐Ythdc2‐Lrp2 axis regulation of neurogenesis might serve as a promising antidepressant strategy.