title: Hopx distinguishes hippocampal from lateral ventricle neural stem cells.
abstract: In the adult dentate gyrus (DG) and in the proliferative zone lining the lateral ventricle (LV-PZ), radial glia-like (RGL) cells are neural stem cells (NSCs) that generate granule neurons. A number of molecular markers including glial fibrillary acidic protein (GFAP), Sox2 and nestin, can identify quiescent NSCs in these two niches. However, to date, there is no marker that distinguishes NSC origin of DG versus LV-PZ. Hopx, an atypical homeodomain only protein, is expressed by adult stem cell populations including those in the intestine and hair follicle. Here, we show that Hopx is specifically expressed in RGL cells in the adult DG, and these cells give rise to granule neurons. Assessed by non-stereological quantitation, Hopx-null NSCs exhibit enhanced neurogenesis evident by an increased number of BrdU-positive cells and doublecortin (DCX)-positive neuroblasts. In contrast, Sox2-positive, quiescent NSCs are reduced in the DG of Hopx-null animals and Notch signaling is reduced, as evidenced by reduced expression of Notch targets Hes1 and Hey2, and a reduction of the number of cells expressing the cleaved, activated form of the Notch1 receptor, the Notch intracellular domain (NICD) in Hopx-null DG. Surprisingly, Hopx is not expressed in RGL cells of the adult LV-PZ, and Hopx-expressing cells do not give rise to interneurons of the olfactory bulb (OB). These findings establish that Hopx expression distinguishes NSCs of the DG from those of the LV-PZ, and suggest that Hopx potentially regulates hippocampal neurogenesis by modulating Notch signaling.
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Deqiang
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Norifumi
authors.initials: N
authors.lastname: Takeda
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Rajan
authors.initials: R
authors.lastname: Jain
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: Manderfield
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Feiyan
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Psychiatry, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: sande@mail.med.upenn.edu.
authors.forename: Stewart A
authors.initials: SA
authors.lastname: Anderson
authors.affiliation: Department of Cell and Developmental Biology, Cardiovascular Institute, Institute for Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: epsteinj@upenn.edu.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Epstein
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D018891:Dentate Gyrus / Q000378:metabolism*; D000089662:Doublecortin Protein; D006624:Hippocampus / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D020547:Lateral Ventricles / Q000378:metabolism*; D051379:Mice; D058953:Neural Stem Cells / Q000378:metabolism*
chemical_list: C000714847:Dcx protein, mouse; D000089662:Doublecortin Protein; C473013:Hod protein, mouse; D018398:Homeodomain Proteins
keywords: Dentate gyrus; Hippocampus; Hopx; Neural stem cell; Neurogenesis; Notch