Tbx2调控ld-NG2+细胞定向诱导分化为功能性肝细胞的分子机制

申请者既往研究发现ld-NG2+细胞是一群受HGF信号通路调节的新型成体肝源性干细胞，但HGF信号通路如何调控其向成熟肝细胞分化的分子机制不清。我们预实验提示，阻断HGF唯一受体cMet，可下调T型框转录因子2(Tbx2)表达、消弱ld-NG2+细胞向成熟肝细胞分化的能力，提示HGF信号通路通过Tbx2激活其下游协调分子调控其向成熟肝细胞定向分化的可能性。进一步研究提示，该过程伴随有CCAAT/增强子结合蛋白γ（c/EBPγ）及肝细胞核因子（HNF6/4a）表达下降，因此，本项目提出“HGF-Tbx2-c/EBPs-HNF6/4a轴”调控dl-NG2+细胞向功能性肝细胞定向诱导分化的学术假说，拟采用多种分子生物学手段如基因过表达、基因干扰、免疫印记、荧光染色、ChIP等，有望深入阐明ld-NG2+细胞的生物学特性，为终末期肝病的生物工程肝治疗提供候选种子细胞奠定基础。

We had demonstrated that HGF/cMet signaling pathway can regulate a novel adult mouse liver-derived stem cell (ld-NG2+cells) functional hepacyte differentiation. Currently, shown by our preliminary data we found that the transcription factor Tbx2 plays a critical role in hepatic cell differentiation of ld-NG2+cells mediated by HGF/cMet signaling pathway. Inhibition of HGF signaling by HGF and cMet functional blocking monoclonal antibodies, reduction of Tbx2 expression has been observed. Down-regulation of c/EBPγand HNF6/4α were also detected by qRT-PCR. Interestingly, those effects impacted on mature hepatic cell generation of ld-NG2+cells. However, its mechanisms are unclear. Therefore, based on our previous and field studies we propose that functional hepatic cell differentiation of ld-NG2+cells may be through “HGF-Tbx2-c/EBPs-HNF6/4α”axis and Tbx2 may play an important role in regulating this pathway. Clarify this hypothesis will provide a novel mechanism in liver adult stem cell differentiation and a novel seed to liver bioengineering for a cell-based therapy and cure of end-stage liver disease.