title: Chemoattractive activity of sonic hedgehog in the adult subventricular zone modulates the number of neural precursors reaching the olfactory bulb.
abstract: The adult subventricular zone (SVZ) supports neural stem cell self-renewal and differentiation and continually gives rise to new neurons throughout adult life. The mechanisms orienting the migration of neuroblasts from the SVZ to the olfactory bulb (OB) via the rostral migratory stream (RMS) have been extensively studied, but factors controlling neuroblast exit from the SVZ remain poorly explored. The morphogen Sonic Hedgehog (Shh) displays proliferative and survival activities toward neural stem cells and is an axonal chemoattractant implicated in guidance of commissural axons during development. We identify here the presence of Shh protein in SVZ extracts and in the cerebrospinal fluid of adult mice, and we demonstrate that migrating neuroblasts in the SVZ and RMS express the Shh receptor Patched. We show that Shh displays a chemoattractive activity in vitro on SVZ-derived neuronal progenitors, an effect blocked by Cur61414, a Smoothened antagonist. Interestingly, Shh-expressing cells grafted above the RMS of adult mice exert a chemoattractive activity on migrating neuroblasts in vivo, thus inducing their accumulation and deviation from their normal migratory pathway. Furthermore, the adenoviral transfer of Shh into the lateral ventricle or the blocking of Shh present in the SVZ of adult mice using its physiological antagonist Hedgehog interacting protein or neutralizing Shh antibodies provides in vivo evidence that Shh can retain SVZ-derived neuroblasts. The ability to modulate the number of neuroblasts leaving the SVZ and reaching the OB through the chemoattractive activity of Shh suggests a novel degree of plasticity in cell migration of this adult stem cell niche.
authors.affiliation: Laboratoire de Neurobiologie Cellulaire et Moleculaire, Signal Transduction and Developmental Neuropharmacology Team, Batiment 33, 1 Avenue de la Terrasse, F-91198, Gif-sur-Yvette, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Angot
authors.forename: Karine
authors.initials: K
authors.lastname: Loulier
authors.forename: Kim T
authors.initials: KT
authors.lastname: Nguyen-Ba-Charvet
authors.forename: Alain-Pierre
authors.initials: AP
authors.lastname: Gadeau
authors.forename: Martial
authors.initials: M
authors.lastname: Ruat
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Traiffort
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology* / Q000378:metabolism; D002478:Cells, Cultured; D002633:Chemotaxis; D004149:Dioxoles / Q000494:pharmacology; D053823:Hedgehog Proteins / Q000134:cerebrospinal fluid / Q000378:metabolism / Q000502:physiology*; D008297:Male; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009830:Olfactory Bulb / Q000166:cytology; D000072079:Patched Receptors; D010879:Piperazines / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000096:biosynthesis; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000502:physiology; D000072086:Smoothened Receptor; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*
chemical_list: C474318:CUR 61414; D004149:Dioxoles; D053823:Hedgehog Proteins; D000072079:Patched Receptors; D010879:Piperazines; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C491022:Smo protein, mouse; D000072086:Smoothened Receptor