Autocrine Mfge8 Signaling Prevents Developmental Exhaustion of the Adult Neural Stem Cell Pool

Cell Stem Cell. 2018 Sep 6;23(3):444-452.e4. doi: 10.1016/j.stem.2018.08.005. Epub 2018 Aug 30.


Adult neurogenesis, arising from quiescent radial-glia-like neural stem cells (RGLs), occurs throughout life in the dentate gyrus. How neural stem cells are maintained throughout development to sustain adult mammalian neurogenesis is not well understood. Here, we show that milk fat globule-epidermal growth factor (EGF) 8 (Mfge8), a known phagocytosis factor, is highly enriched in quiescent RGLs in the dentate gyrus. Mfge8-null mice exhibit decreased adult dentate neurogenesis, and furthermore, adult RGL-specific deletion of Mfge8 leads to RGL overactivation and depletion. Similarly, loss of Mfge8 promotes RGL activation in the early postnatal dentate gyrus, resulting in a decreased number of label-retaining RGLs in adulthood. Mechanistically, loss of Mfge8 elevates mTOR1 signaling in RGLs, inhibition of which by rapamycin returns RGLs to quiescence. Together, our study identifies a neural-stem-cell-enriched niche factor that maintains quiescence and prevents developmental exhaustion of neural stem cells to sustain continuous neurogenesis in the adult mammalian brain.

Keywords: Mfge8; PTEN; RGL; adult neural stem cells; hippocampus; mTOR; neurogenesis; quiescence.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult Stem Cells / metabolism*
  • Animals
  • Antigens, Surface / metabolism*
  • Cells, Cultured
  • Mechanistic Target of Rapamycin Complex 1 / metabolism
  • Mice
  • Mice, Knockout
  • Milk Proteins / metabolism*
  • Neural Stem Cells / metabolism*
  • Signal Transduction*


  • Antigens, Surface
  • Mfge8 protein, mouse
  • Milk Proteins
  • Mechanistic Target of Rapamycin Complex 1