title: Effects of estradiol in adult neurogenesis and brain repair in zebrafish.
abstract: The brain of the adult teleost fish exhibits intense neurogenic activity and an outstanding capability for brain repair. Remarkably, the brain estrogen-synthesizing enzyme, aromatase B, is strongly expressed, particularly in adult fishes, in radial glial cells, which act as progenitors. Using zebrafish, we tested the hypothesis that estrogens affect adult neurogenesis and brain regeneration by modulating the neurogenic activity of radial glial cells. To investigate this, the estrogenic environment was modified through inhibition of aromatase activity, blockade of nuclear estrogen receptors, or estrogenic treatments. Estrogens significantly decreased cell proliferation and migration at the olfactory bulbs/telencephalon junction and in the mediobasal hypothalamus. It also appears that cell survival is reduced at the olfactory bulbs/telencephalon junction. We also developed a model of telencephalic lesion to assess the role of aromatase and estrogens in brain repair. Proliferation increased rapidly immediately after the lesion in the parenchyma of the injured telencephalon, while proliferation at the ventricular surface appeared after 48 h and peaked at 7 days. At this time, most proliferative cells express Sox2, however, none of these Sox2 positive cells correspond to aromatase B-positive radial glial cells. Interestingly, aromatase B expression was significantly reduced 48 h and 7 days after the injury, but surprisingly, at 72 h after lesion, aromatase B expression appeared de novo expressed in parenchyma cells, suggesting a role for this ectopic expression of aromatase in brain repair mechanisms. Altogether these data suggest that estrogens modulate adult, but not reparative neurogenesis, in zebrafish.
authors.affiliation: Neuroendocrine Effects of Endocrine Disruptors, Inserm, IRSET, U1085, Université de Rennes 1, Rennes, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Diotel
authors.forename: Colette
authors.initials: C
authors.lastname: Vaillant
authors.forename: Cyril
authors.initials: C
authors.lastname: Gabbero
authors.forename: Svetlana
authors.initials: S
authors.lastname: Mironov
authors.forename: Alexis
authors.initials: A
authors.lastname: Fostier
authors.forename: Marie-Madeleine
authors.initials: MM
authors.lastname: Gueguen
authors.forename: Isabelle
authors.initials: I
authors.lastname: Anglade
authors.forename: Olivier
authors.initials: O
authors.lastname: Kah
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Pellegrini
mesh_terms: D053687:Adult Stem Cells / Q000187:drug effects* / Q000502:physiology; D000367:Age Factors; D000818:Animals; D001930:Brain Injuries / Q000503:physiopathology*; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004958:Estradiol / Q000494:pharmacology*; D008297:Male; D008954:Models, Biological; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology; D055495:Neurogenesis / Q000187:drug effects*; D016548:Prosencephalon / Q000187:drug effects / Q000502:physiology; D014945:Wound Healing / Q000187:drug effects* / Q000502:physiology; D015027:Zebrafish
chemical_list: D004958:Estradiol