Transforming growth factor beta promotes neuronal cell fate of mouse cortical and hippocampal progenitors in vitro and in vivo: identification of Nedd9 as an essential signaling component.
Transforming Growth Factor beta (Tgfbeta) and associated signaling effectors are expressed in the forebrain, but little is known about the role of this multifunctional cytokine during forebrain development. Using hippocampal and cortical primary cell cultures of developing mouse brains, this study identified Tgfbeta-regulated genes not only associated with cell cycle exit of progenitors but also with adoption of neuronal cell fate. Accordingly, we observed not only an antimitotic effect of Tgfbeta on progenitors but also an increased expression of neuronal markers in Tgfbeta treated cultures. This effect was dependent upon Smad4. Furthermore, in vivo loss-of-function analyses using Tgfbeta2(-/-)/Tgfbeta3(-/-) double mutant mice showed the opposite effect of increased cell proliferation and fewer neurons in the cerebral cortex and hippocampus. Gata2, Runx1, and Nedd9 were candidate genes regulated by Tgfbeta and known to be involved in developmental processes of neuronal progenitors. Using siRNA-mediated knockdown, we identified Nedd9 as an essential signaling component for the Tgfbeta-dependent increase in neuronal cell fate. Expression of this scaffolding protein, which is mainly described as a signaling molecule of the beta1-integrin pathway, was not only induced after Tgfbeta treatment but was also associated with morphological changes of the Nestin-positive progenitor pool observed upon exposure to Tgfbeta.
Vogel
Tanja
T
Department of Neuroanatomy, Centre of Anatomy, Georg-August-University, 37075 Goettingen, Germany.
Ahrens
Sandra
S
Büttner
Nicole
N
Krieglstein
Kerstin
K
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D004622:Embryo, Mammalian; D053595:Embryonic Stem Cells / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D006624:Hippocampus / Q000166:cytology*; D019394:Ki-67 Antigen / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D018709:Statistics, Nonparametric; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology
D048868:Adaptor Proteins, Signal Transducing; D004791:Enzyme Inhibitors; D019394:Ki-67 Antigen; C505592:NEDD9 protein, mouse; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D016212:Transforming Growth Factor beta; D001973:Bromodeoxyuridine