RESUMO
Mouse pluripotent stem cells (PSCs), such as ES cells and induced PSCs (iPSCs), are an excellent system to investigate the molecular and cellular mechanisms involved in early embryonic development. The signaling pathways orchestrated by leukemia inhibitor factor/STAT3, Wnt/ß-catenin, and FGF/MEK/ERK play key roles in the generation of pluripotency. However, the function of TGF-ß signaling in this process remains elusive. Here we show that inhibiting TGF-ß signaling with its inhibitor SB431542 can substitute for Oct4 during reprogramming. Moreover, inhibiting TGF-ß signaling can sustain the pluripotency of iPSCs and ES cells through modulating FGF/MEK/ERK signaling. Therefore, this study reveals a novel function of TGF-ß signaling inhibition in the generation and maintenance of PSCs.
Assuntos
Benzamidas/farmacologia , Reprogramação Celular/efeitos dos fármacos , Dioxóis/farmacologia , Células-Tronco Embrionárias/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Fator 3 de Transcrição de Octâmero/metabolismo , Fator de Crescimento Transformador beta/antagonistas & inibidores , Animais , Western Blotting , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Embrião de Mamíferos/citologia , Embrião de Mamíferos/efeitos dos fármacos , Embrião de Mamíferos/metabolismo , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Embrionárias/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Fator 1 de Crescimento de Fibroblastos/genética , Fator 1 de Crescimento de Fibroblastos/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Imunofluorescência , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/metabolismo , MAP Quinase Quinase 1/genética , MAP Quinase Quinase 1/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fator 3 de Transcrição de Octâmero/genética , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacosRESUMO
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
RESUMO
The paraventricular nucleus of hypothalamus plays important roles in the regulation of energy balance and fetal growth. However, the molecular mechanisms underlying its formation and function have not been clearly elucidated. Various mutations in the human COUP-TFII gene, which encodes a nuclear receptor, result in growth retardation, congenital diaphragmatic hernia and congenital heart defects. Here, we show that COUP-TFII gene is expressed in the developing hypothalamus in mouse. The ventral forebrain-specific RXCre/+; COUP-TFII F/F mutant mice display growth retardation. The development of the paraventricular nucleus of hypothalamus is compromised in the COUP-TFII mutant mainly because of increased apoptosis and mis-migration of the Brn2+ neurons. Moreover, hypoplastic anterior pituitary with blood cell clusters and shrunken posterior pituitary lacking AVP/OT neuron innervations are observed in the mutant, indicating the failure of formation of the hypothalamic-pituitary axis. Mechanistic studies show that the expression of Bdnf and Nrp1 genes is reduced in the mutant embryo, and that Bdnf is a direct downstream target of the COUP-TFII protein. Thus, our findings provide a novel functional validation that COUP-TFII gene promotes the expression of Bdnf and Nrp1 genes to ensure the appropriate morphogenesis of the hypothalamic-pituitary axis, especially the paraventricular nucleus of hypothalamus, and to prevent growth retardation.