title: DCX-expressing cells in the vicinity of the hypothalamic neurogenic niche: a comparative study between mouse, sheep, and human tissues.
abstract: Neural stem and precursor cells persist postnatally throughout adulthood and are capable of responding to numerous endogenous and exogenous signals by modifying their proliferation and differentiation. Whereas adult neurogenesis has been extensively studied in the dentate gyrus of the hippocampal formation and in the subventricular zone adjacent to the wall of the lateral ventricles, we and others have recently reported constitutive adult neurogenesis in other brain structures, including the hypothalamus. In this study, we used immunohistochemistry to study the expression of the neuroblast marker doublecortin (DCX), and compared its expression pattern in adult ovine, mouse, and human hypothalamic tissues. Our results indicate that DCX-positive cells resembling immature and developing neurons occur in a wide range of hypothalamic nuclei in all three species, although with different distribution patterns. In addition, the morphology of DCX-positive cells varied depending on their location. DCX-positive cells near the third ventricle had the morphology of very immature neuroblasts, a round shape with no processes, whereas those located deeper in the parenchyma such as in the ventromedial nucleus were fusiform and showed a bipolar morphology. Extending this observation, we showed that among the cohort of immature neurons entering the ventromedial nucleus, some appeared to undergo maturation, as revealed by the partial colocalization of DCX with markers of more mature neurons, e.g., human neuronal protein C and D (HuC/D). This study provides further confirmation of the existence of an adult hypothalamic neurogenic niche and argues for the potential existence of a migratory path within the hypothalamus.
authors.affiliation: INRA, Unité Mixte de Recherche (UMR) 85 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France; Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 7247, F-37380, Nouzilly, France; Université de Tours, F-37041, Tours, France; Institut Français du Cheval et de l'équitation (IFCE), F-37380, Nouzilly, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Batailler
authors.forename: Marine
authors.initials: M
authors.lastname: Droguerre
authors.forename: Marc
authors.initials: M
authors.lastname: Baroncini
authors.forename: Christian
authors.initials: C
authors.lastname: Fontaine
authors.forename: Vincent
authors.initials: V
authors.lastname: Prevot
authors.forename: Martine
authors.initials: M
authors.lastname: Migaud
mesh_terms: D000368:Aged; D000818:Animals; D015331:Cohort Studies; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007031:Hypothalamus / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis*; D055495:Neurogenesis / Q000502:physiology*; D009479:Neuropeptides / Q000096:biosynthesis*; D012756:Sheep; D013045:Species Specificity; D055815:Young Adult
chemical_list: C000714328:DCX protein, human; C000714847:Dcx protein, mouse; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides
keywords: adult neurogenesis; hypothalamus; neuroblast; neurogenic niche; neuronal maturation