title: Atg5 and Ambra1 differentially modulate neurogenesis in neural stem cells.
abstract: Neuroepithelial cells undergoing differentiation efficiently remodel their cytoskeleton and shape in an energy-consuming process. The capacity of autophagy to recycle cellular components and provide energy could fulfill these requirements, thus supporting differentiation. However, little is known regarding the role of basal autophagy in neural differentiation. Here we report an increase in the expression of the autophagy genes Atg7, Becn1, Ambra1 and LC3 in vivo in the mouse embryonic olfactory bulb (OB) during the initial period of neuronal differentiation at E15.5, along with a parallel increase in neuronal markers. In addition, we observed an increase in LC3 lipidation and autophagic flux during neuronal differentiation in cultured OB-derived stem/progenitor cells. Pharmacological inhibition of autophagy with 3-MA or wortmannin markedly decreased neurogenesis. These observations were supported by similar findings in two autophagy-deficient genetic models. In Ambra1 loss-of-function homozygous mice (gt/gt) the expression of several neural markers was decreased in the OB at E13.5 in vivo. In vitro, Ambra1 haploinsufficient cells developed as small neurospheres with an impaired capacity for neuronal generation. The addition of methylpyruvate during stem/progenitor cell differentiation in culture largely reversed the inhibition of neurogenesis induced by either 3-MA or Ambra1 haploinsufficiency, suggesting that neural stem/progenitor cells activate autophagy to fulfill their high energy demands. Further supporting the role of autophagy for neuronal differentiation Atg5-null OB cells differentiating in culture displayed decreased TuJ1 levels and lower number of cells with neurites. These results reveal new roles for autophagy-related molecules Atg5 and Ambra1 during early neuronal differentiation of stem/progenitor cells.
authors.affiliation: 3D Lab (Development, Differentiation & Degeneration), Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Vázquez
authors.forename: Ana I
authors.initials: AI
authors.lastname: Arroba
authors.forename: Francesco
authors.initials: F
authors.lastname: Cecconi
authors.forename: Enrique J
authors.initials: EJ
authors.lastname: de la Rosa
authors.forename: Patricia
authors.initials: P
authors.lastname: Boya
authors.forename: Flora
authors.initials: F
authors.lastname: de Pablo
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001343:Autophagy / Q000187:drug effects; D000071187:Autophagy-Related Protein 5; D002454:Cell Differentiation / Q000187:drug effects; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D057895:Haploinsufficiency / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008869:Microtubule-Associated Proteins / Q000172:deficiency / Q000378:metabolism*; D058953:Neural Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects / Q000378:metabolism; D055495:Neurogenesis / Q000187:drug effects; D009830:Olfactory Bulb / Q000166:cytology / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D011773:Pyruvates / Q000494:pharmacology; D018874:Spheroids, Cellular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C521754:Ambra1 protein, mouse; C495773:Atg5 protein, mouse; D000071187:Autophagy-Related Protein 5; D008869:Microtubule-Associated Proteins; D011773:Pyruvates; C025946:3-methyladenine; D000225:Adenine