转甲状腺素蛋白促进胆固醇结石形成的机制研究

Background: High cholesterol secretion was the key factor of gallstone formation, the key protein in bile might promote cholesterol gallstone formation via involve in cholesterol metabolism and cholesterol nucleation. TTR was an promote nucleation protein with high expression in hepatic cell, our preliminary results demonstrated that TTR could involve in the key enzyme of cholesterol secretion and cholesterol transport factors (ABCB, ABCG) in hepatic cells via the nuclear receptor pathway (FXR, LXR), and then caused the cholesterol high secretion and increased cholesterol input to hepatic cells; when the cholesterol was higher expression in bile, the nucleation factor TTR could promote cholesterol-lipid vesicle changed to nucleation phase, and TTR could promote cholesterol crystal precipitation and aggregation from bile vesicle and then gallstone formed. The clinical pathology, cell cultivation cell in vitro and lithic mice model are used in this research; we should investigate the histic, cellular and molecular change of the two-ways regulation of TTR and its interaction with cholesterol metabolism in hepatic cell via RNA interference, RT-PCR, Western Blot techniques and mice model in vivo, then the role of this hypothesis in cholesterol gallstone formation should be studied. Objective: This study aimed to determine the specific function of TTR which could involve in cholesterol metabolism in hepatic cell and promote nucleation in cholesterol gallstone formation.

胆固醇高表达是胆石形成的关键因素，胆汁中蛋白作用于胆固醇代谢及胆固醇成核过程参与结石形成。体外实验证实TTR促进胆固醇结石形成，TTR是肝脏高表达的一种促成核蛋白， 我们推测TTR在肝细胞中通过核受体信号(FXR，LXR)作用于肝细胞胆固醇分泌关键酶及胆固醇转运因子（ABCB，ABCG），引起胆固醇分泌及胆固醇入肝增加，最终导致胆固醇过表达；进而成核因子TTR在过饱和胆汁中促进胆固醇-磷脂泡成核相的转变，引起胆固醇结晶成核，导致结石生长、发展。本研究应用临床病理、体外细胞培养、胆固醇结石小鼠模型及RNA干扰、qRT-PCR、Western Blot、激光共聚焦、小动物实验等技术，从组织学、细胞学、分子生物学水平，通过双向调节TTR蛋白，研究在不同胆固醇代谢状态下TTR与肝细胞胆固醇合成转运之间的相互作用，明确TTR促进胆固醇结石形成的作用机制，为进一步理解胆固醇结石的发病机制及胆石病防治提