RESUMO
Inflammatory mediators, many of which activate the signaling of nuclear factor kappa B (NFκB), have received increasing attention in the field of neurogenesis. NFκB signaling regulates neurite outgrowth and neural plasticity as well as the proliferation/apoptosis and terminal differentiation of neural stem cells (NSCs). Early neurogenesis from NSCs produces identical progeny through symmetric division and committed daughter cells through asymmetric division. Here, we show that NFκB signaling is required for NSC initial differentiation. The canonical IKKß/IκBα/p65 pathway is activated during the initial stages of neural differentiation induced by treatment with TNFα or withdrawal of epidermal growth factor/basic fibroblast growth factor. NSC-specific inhibition of NFκB in transgenic mice causes an accumulation of Nestin(+) /Sox2(+) /glial fibrillary acidic protein(+) NSCs. Inhibition of NFκB signaling in vitro blocks differentiation and asymmetric division and maintains NSCs in an undifferentiated state. The induction of initial differentiation and asymmetry by NFκB signaling occurs through the inhibition of C/EBPß expression. Our data reveal a novel function of NFκB signaling in early neurogenesis and provide insight into the molecular mechanisms underlying neurodevelopmental disorders and neurodegenerative diseases.
Assuntos
Diferenciação Celular , NF-kappa B/metabolismo , Células-Tronco Neurais/fisiologia , Transdução de Sinais , Animais , Divisão Celular Assimétrica , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Proliferação de Células , Células Cultivadas , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Proteína Glial Fibrilar Ácida/metabolismo , Quinase I-kappa B/genética , Quinase I-kappa B/metabolismo , Proteínas de Filamentos Intermediários/metabolismo , Ventrículos Laterais/citologia , Masculino , Camundongos , Camundongos Transgênicos , Regeneração Nervosa , Proteínas do Tecido Nervoso/metabolismo , Nestina , Células-Tronco Neurais/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismoRESUMO
BACKGROUND: Conditioned medium (CM) from human amnion-derived mesenchymal stem cells (hAMSCs) exhibits excellent pro-angiogenic capacity, and circ-100290 participates in this process. Autophagy is involved in the relevant mechanisms of angiogenesis, but it is unclear whether autophagy is related to the pro-angiogenesis effect of hAMSCs. This research sought to determine whether autophagy involved in the process of pro-angiogenesis induced by hAMSCs might be regulated by circ-100290. METHODS: Upon treatment with CM from hAMSC or 3-methyladenine (3-MA), autophagosomes in human umbilical vein endothelial cells (HUVECs) were observed by transmission electron microscopy. HUVECs' angiogenic ability was evaluated by in vitro assays (transwell, wound healing, tube formation) and an in vivo Matrigel plug assay. Specific small interfering RNAs (siRNA) or inhibitors were used to regulate circ-100290 expression. Additionally, western blot and quantitative reverse transcription-polymerase chain reaction (RT-qPCR) were used to evaluate expression of the following indicators: Beclin-1, LC3-II, matrix metalloproteinase 2 (MMP2), MMP9, vascular endothelial growth factor (VEGF)-A, and endothelial nitric oxide synthase (eNOS). RESULTS: Incubation with hAMSC-CM increased autophagy, angiogenesis and the expressions of VEGF-A and eNOS in HUVECs, all of which were inhibited by 3-MA. Knocking down circ-100290 in hAMSC-CM-treated HUVECs reduced Beclin-1 expression and inhibited autophagy. This resulted in lower angiogenesis in the Matrigel plug assay showing that reduced angiogenesis occurred after circ-100290 silencing in hAMSC-CM-treated HUVECs. CONCLUSIONS: Circ-100290 promotes autophagy-mediated angiogenesis in hAMSC-CM-treated HUVECs.