title: β1-integrin restricts astrocytic differentiation of adult hippocampal neural stem cells.
abstract: Integrins are transmembrane receptors that mediate cell-extracellular matrix and cell-cell interactions. The β1-integrin subunit is highly expressed by embryonic neural stem cells (NSCs) and is critical for NSC maintenance in the developing nervous system, but its role in the adult hippocampal niche remains unexplored. We show that β1-integrin expression in the adult mouse dentate gyrus (DG) is localized to radial NSCs and early progenitors, but is lost in more mature progeny. Although NSCs in the hippocampal subgranular zone (SGZ) normally only infrequently differentiate into astrocytes, deletion of β1-integrin significantly enhanced astrocyte differentiation. Ablation of β1-integrin also led to reduced neurogenesis as well as depletion of the radial NSC population. Activation of integrin-linked kinase (ILK) in cultured adult NSCs from β1-integrin knockout mice reduced astrocyte differentiation, suggesting that at least some of the inhibitory effects of β1-integrin on astrocytic differentiation are mediated through ILK. In addition, β1-integrin conditional knockout also resulted in extensive cellular disorganization of the SGZ as well as non-neurogenic regions of the DG. The effects of β1-integrin ablation on DG structure and astrogliogenesis show sex-specific differences, with the effects following a substantially slower time-course in males. β1-integrin thus plays a dual role in maintaining the adult hippocampal NSC population by supporting the structural integrity of the NSC niche and by inhibiting astrocytic lineage commitment. GLIA 2016;64:1235-1251.
authors.affiliation: Department of Neurology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, 60611.
authors.forename: Sarah M
authors.identifier: 0000-0002-5674-3124
authors.initials: SM
authors.lastname: Brooker
authors.affiliation: Department of Neurology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, 60611.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Bond
authors.affiliation: Department of Neurology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, 60611.
authors.forename: Chian-Yu
authors.initials: CY
authors.lastname: Peng
authors.affiliation: Department of Neurology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, 60611.
authors.forename: John A
authors.initials: JA
authors.lastname: Kessler
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D000089622:Doublecortin Domain Proteins; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D006624:Hippocampus / Q000166:cytology*; D019012:Integrin beta1 / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D058953:Neural Stem Cells / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism; D012737:Sex Factors
chemical_list: D000089622:Doublecortin Domain Proteins; D019012:Integrin beta1; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides
keywords: astrocytes; hippocampus; integrins; neural stem cells; neurogenesis