title: Steroid modulation of neurogenesis: Focus on radial glial cells in zebrafish.
abstract: Estrogens are known as steroid hormones affecting the brain in many different ways and a wealth of data now document effects on neurogenesis. Estrogens are provided by the periphery but can also be locally produced within the brain itself due to local aromatization of circulating androgens. Adult neurogenesis is described in all vertebrate species examined so far, but comparative investigations have brought to light differences between vertebrate groups. In teleost fishes, the neurogenic activity is spectacular and adult stem cells maintain their mitogenic activity in many proliferative areas within the brain. Fish are also quite unique because brain aromatase expression is limited to radial glia cells, the progenitor cells of adult fish brain. The zebrafish has emerged as an interesting vertebrate model to elucidate the cellular and molecular mechanisms of adult neurogenesis, and notably its modulation by steroids. The main objective of this review is to summarize data related to the functional link between estrogens production in the brain and neurogenesis in fish. First, we will demonstrate that the brain of zebrafish is an endogenous source of steroids and is directly targeted by local and/or peripheral steroids. Then, we will present data demonstrating the progenitor nature of radial glial cells in the brain of adult fish. Next, we will emphasize the role of estrogens in constitutive neurogenesis and its potential contribution to the regenerative neurogenesis. Finally, the negative impacts on neurogenesis of synthetic hormones used in contraceptive pills production and released in the aquatic environment will be discussed.
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France. Electronic address: elisabeth.pellegrini@univ-rennes1.fr.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Pellegrini
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France; Inserm UMR 1188, Diabète athérothrombose Thérapies Réunion Océan Indien (DéTROI), plateforme CYROI, Sainte-Clotilde F-97490, France; Université de La Réunion, UMR 1188, Sainte-Clotilde F-97490, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Diotel
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France.
authors.forename: Colette
authors.initials: C
authors.lastname: Vaillant-Capitaine
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France; Laboratorio de Ictiología, Instituto Nacional de Limnología (INALI. CONICET-UNL), Paraje El Pozo, Ciudad Universitaria UNL, 3000 Santa Fe, Argentina.
authors.forename: Rita
authors.initials: R
authors.lastname: Pérez Maria
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France.
authors.forename: Marie-Madeleine
authors.initials: MM
authors.lastname: Gueguen
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France; Laboratoire de Biosurveillance de l'Environnement, Unité d'Ecologie côtière et d'Ecotoxicologie, Faculté des Sciences de Bizerte, Zarzouna 7021, Tunisia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Nasri
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France.
authors.forename: Joel
authors.initials: J
authors.lastname: Cano Nicolau
authors.affiliation: Inserm U1085, Université de Rennes 1, Research Institute in Health, Environment and Occupation, 35000 Rennes, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Kah
mesh_terms: D000818:Animals; D001141:Aromatase / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D052244:Endocrine Disruptors / Q000009:adverse effects; D004967:Estrogens / Q000378:metabolism*; D055495:Neurogenesis / Q000187:drug effects; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015027:Zebrafish / Q000502:physiology*; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D052244:Endocrine Disruptors; D004967:Estrogens; D018377:Neurotransmitter Agents; D029961:Zebrafish Proteins; D001141:Aromatase
keywords: Aromatase; Endocrine disruptors; Estradiol; Neurosteroids; Radial glial progenitor cells; Zebrafish