S-nitrosylation抑制Notch-1活化诱导间充质干细胞向肝细胞定向分化的机制研究

间充质干细胞（MSC）分化成肝细胞的细胞移植或生物人工肝制备在肝脏疾病中有广阔的应用前景，但MSC分化成肝细胞的机制亟需阐明。研究发现MSC高表达Notch-1，抑制Notch-1及Notch信号通路活化促进MSC分化成肝细胞；预实验发现，Notch-1发生巯基亚硝基化（S-nitrosylation, SNO）抑制Notch-1自身活化，且SNO内源性抑制剂促进Notch-1表达，而SNO激动剂可促进MSC向肝细胞分化。据此提出假设：Notch-1发生亚硝基化抑制Notch-1及其信号通路的活化，促进MSC向肝细胞分化。课题拟开展如下研究：验证Notch-1参与脐带间充质干细胞向肝细胞的定向分化；证明SNO可抑制Notch-1活化；阐明Notch-1经其半胱氨酸位点诱发的SNO调控脐带间充质干细胞向肝细胞定向分化的机制。结果有望阐明MSC向肝细胞分化的分子机制及为肝病治疗提供实验基础。

Cell transplantation or the preparation of biological artificial liver derived from mesenchymal stem cells (MSC) differentiating into hepatocytes have a broad application prospect in end-stage liver diseases, but the mechanism of induced differentiation of MSC into hepatocytes needs to be clarified. Studies have found that Notch-1 is highly expressed in MSC, and inhibition of Notch-1 and its downstream signaling pathway can promote the differentiation of MSC into hepatocytes. The pilot experiments showed that S-nitrosylation (SNO) of Notch-1 inhibited the activation of Notch-1, and endogenous SNO inhibitors promoted the expression of Notch-1, while exogenous SNO agonists promoted the differentiation of MSC into liver cells. Based on this, the hypothesis was put forward: the regulation of S-nitrosylation of Notch-1(SNO.Notch-1) will inhibit the activation of Notch-1 and Notch signaling pathway, which induces the differentiation of MSCs into hepatocytes. This project intends to study: verify that Notch-1 is involved in the differentiation of umbilical cord mesenchymal stem cells into hepatocytes; prove that S-nitrosylation can inhibit the activation of Notch-1; elucidate that Notch-1 regulates the differentiation of umbilical cord mesenchymal stem cells into hepatocytes by S-nitrosylation induced by Notch-1 cysteine site. In this way, the mechanism of MSCs differentiation into hepatocytes would be elucidated and would provide the experimental basis for the treatment of liver diseases.