Phagocytic activity of neuronal progenitors regulates adult neurogenesis
- 31 July 2011
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 13 (9), 1076-1083
- https://doi.org/10.1038/ncb2299
Abstract
Although thousands of new neurons are generated during adult life, only a few survive, and the dying neurons are removed by phagocytosis. Ravichadran and colleagues find that in mice a specific class of neuronal progenitor cells expressing doublecortin is responsible for a significant proportion of the phagocytic activity within the neurogenic zones, through activation of the ELMO1–Rac pathway. Disruption of this process impairs neurogenesis. Whereas thousands of new neurons are generated daily during adult life, only a fraction of them survive and become part of neural circuits; the rest die, and their corpses are presumably cleared by resident phagocytes. How the dying neurons are removed and how such clearance influences neurogenesis are not well understood. Here, we identify an unexpected phagocytic role for the doublecortin (DCX)-positive neuronal progenitor cells during adult neurogenesis. Our in vivo andex vivo studies demonstrate that DCX+ cells comprise a significant phagocytic population within the neurogenic zones. Intracellular engulfment protein ELMO1, which promotes Rac activation downstream of phagocytic receptors, was required for phagocytosis by DCX+ cells. Disruption of engulfment in vivo genetically (in Elmo1-null mice) or pharmacologically (in wild-type mice) led to reduced uptake by DCX+ cells, accumulation of apoptotic nuclei in the neurogenic niches and impaired neurogenesis. Collectively, these findings indicate a paradigm wherein DCX+ neuronal precursors also serve as phagocytes, and that their phagocytic activity critically contributes to neurogenesis in the adult brain.Keywords
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