title: Specific ablation of Nampt in adult neural stem cells recapitulates their functional defects during aging.
abstract: Neural stem/progenitor cell (NSPC) proliferation and self-renewal, as well as insult-induced differentiation, decrease markedly with age. The molecular mechanisms responsible for these declines remain unclear. Here, we show that levels of NAD(+) and nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme in mammalian NAD(+) biosynthesis, decrease with age in the hippocampus. Ablation of Nampt in adult NSPCs reduced their pool and proliferation in vivo. The decrease in the NSPC pool during aging can be rescued by enhancing hippocampal NAD(+) levels. Nampt is the main source of NSPC NAD(+) levels and required for G1/S progression of the NSPC cell cycle. Nampt is also critical in oligodendrocytic lineage fate decisions through a mechanism mediated redundantly by Sirt1 and Sirt2. Ablation of Nampt in the adult NSPCs in vivo reduced NSPC-mediated oligodendrogenesis upon insult. These phenotypes recapitulate defects in NSPCs during aging, giving rise to the possibility that Nampt-mediated NAD(+) biosynthesis is a mediator of age-associated functional declines in NSPCs.
authors.affiliation: Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: Liana R
authors.initials: LR
authors.lastname: Stein
authors.affiliation: Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA imaishin@wustl.edu.
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Imai
mesh_terms: D053687:Adult Stem Cells / Q000378:metabolism*; D000375:Aging / Q000502:physiology*; D000818:Animals; D001973:Bromodeoxyuridine; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D003433:Crosses, Genetic; D003471:Cuprizone; D016207:Cytokines / Q000172:deficiency / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D051379:Mice; D008822:Mice, Transgenic; D058953:Neural Stem Cells / Q000378:metabolism*; D009537:Nicotinamide Mononucleotide; D054409:Nicotinamide Phosphoribosyltransferase / Q000172:deficiency / Q000378:metabolism*
chemical_list: D016207:Cytokines; D009537:Nicotinamide Mononucleotide; D003471:Cuprizone; D054409:Nicotinamide Phosphoribosyltransferase; C495867:nicotinamide phosphoribosyltransferase, mouse; D001973:Bromodeoxyuridine
keywords: Nampt; adult neural stem cells; aging; differentiation; proliferation