在临床治疗中，肝脏／肝细胞移植是对终末期肝病，急性肝衰竭唯一的治疗方法。但这些运用严重受限于器官和细胞的来源严重不足，大量获得功能性的肝细胞是当前研究热点。我们近期研究发现，肝细胞移植后会迅速转分化至肝脏祖细胞状态进行增殖，这一状态下的肝细胞也能在体外大量扩增，联用GSK3b，ROCR1信号通路抑制剂可以促进肝细胞这一转分化过程，进而促进肝细胞体内增殖，相关评定工作和机制研究正在深入进行。近期报道发现联用TGFb，GSK3b，ROCR1信号通路抑制剂，细胞因子wnt3a，TNFa等可在体外扩增小鼠和人肝细胞。但这些方法对人肝细胞的扩增效率有限，且多化合物和细胞因子的运用难以用于临床治疗。基于上述问题，我们建立了扩增肝细胞化合物的筛选平台。筛选获得一GPCR受体激动剂C21，初步发现其能有效扩增小鼠和人肝细胞，我们将深入评价该化合物和其作用的受体在肝脏再生中的作用，为奠定临床运用基础。

Liver diseases have high morbidity and mortality in the world. Orthotopic liver transplantation (OLT) or hepatocytes transplantation is the only effective way to treatment of end-stage liver disease, acute liver failure and liver-based metabolic defects. But, these methods were limited by the availability of donor organs and functional hepatocytes. To resolve these problems, scientists put many efforts on the research of expansion primary hepatocytes. Recently, we found that primary hepatocyte could transdifferentiation to hepatic progenitor cell type when transplanted and expanded in vivo. Moreover, these hepatic progenitor cells obtained efficient proliferative capacity when cultured in vitro. More interestingly, combined using GSK3b and ROCR1 signaling inhibitor CHIR99021 and Y27632 could promote hepatocyte transdifferentiation to hepatic progenitor cell type and promote hepatocyte proliferation in vivo. Recently, studies have demonstrated that chemical cocktails Repsox CHIR99021 and Y27632 combination of cytokines TNFa or Wnt3a could expand mice or human hepatocyte in vitro. But these methods could only expand human hepatocyte for about 15 times. On the other hand, the cytokines are always very expensive and difficult to obtain. Moreover, combination using chemical cocktails and cytokines are not favored in therapeutic applications. To resolve these problems, we started to set up the chemical screening platform for expanding mice and human primary hepatocytes in vitro. As the recently results, we found one GPCR agonist could efficiently expand mice and human hepatocytes in vitro. For the further studies, we will do more researches on exploring the functions, expanding efficiency and the mechanism of this chemical, and explore the role of this GPCR on liver regeneration..In this project, we focused on the research of using chemicals to expand primary hepatocytes in vitro and promote liver regeneration in vivo. We believe we could provide new methods to expand primary hepatocytes in vitro and in vivo for functional and clinically applications.