Molecular Basis of Human Hepatic Progenitor Cell Formation

描述（由申请人提供）：我们之前已经描述了一种方案，该方案允许我们有效且可重复地将人类iPSCs转化为具有肝细胞大部分特征的细胞。我们已经发表了使用患者特异性iPSCs来模拟感染性肝病、先天性肝脏代谢错误和早期细胞命运决定的成功成果。该过程使用完全定义的条件，结果导致同步分化，这似乎与正常肝细胞形成过程中发生的已知发育事件密切相关。在提交的建议中，我们建议使用这种人体模型来揭示肝祖细胞从最终内胚层产生的分子机制。肝祖细胞的描述历来难以进行分子分析，因为这一过程是动态的，而且肝祖细胞是一个短暂的群体，难以在模式生物中大量获取。由于从多能干细胞形成的肝祖细胞是同步的和可复制的，它提供了一个适合基因操作和分子生化分析的细胞群。我们建议利用这一点来定义将作用于内胚层的信号分子与决定肝祖细胞生成的转录因子的作用联系起来的分子事件。我们相信，该提案的成功将大大推进我们对肝细胞形成的基本分子基础的理解，并有助于实现干细胞在肝脏疾病研究和治疗中的全部潜力。

DESCRIPTION (provided by applicant): We have previously described a protocol that allows us to efficiently and reproducibly convert human iPSCs into cells that share most of the characteristics of hepatocytes. We have published our success in using patient specific iPSCs to model infectious liver disease, inborn errors of hepatic metabolism, and early cell fate decisions. The procedure uses wholly defined conditions and as a consequence results in a synchronous differentiation that appears to closely mirror the known development events that occur during normal hepatocyte formation. In the submitted proposal we propose to use this human model to uncover the molecular mechanisms through which hepatic progenitor cells are generated from definitive endoderm. Specification of the hepatic progenitors has historically been recalcitrant to molecular analysis because the process is dynamic and hepatic progenitor cells are a transient population that are difficult to access in quantity in model organisms. Because the formation of the hepatic progenitors from iPSCs is synchronous and reproducible it affords access to a cell population that is amenable to genetic manipulation and molecular and biochemical analyses. We propose to exploit this to define the molecular events that link signaling molecules that act on the endoderm to the action of transcription factors that define the generation of hepatic progenitor cells. We believe that success in the proposal will significantly advance our understanding of the fundamental molecular basis of hepatocyte formation and help realize the full potential of stem cells in the study and treatment of liver disease.