载脂蛋白A-V在早期预警和降低重症肝炎发生中的作用及机理研究

Lipid metabolic disorder is one of the important factors affecting the progress of chronic liver disease. Our previous research showed that the expression of apolipoprotein A-V (Apo A-V) was significantly reduced in mouse with severe hepatitis; and TLR4 signaling pathway, which played a bridge role in lipid metabolism disorders and chronic inflammation was also activated in severe hepatitis mouse model. In this project, we plan to establish two different mouse models with severe hepatitis, and collect serum samples of patients with different severity of liver disease, so as to observe whether there is an early predicting warning effect of Apo A-V reduction in predicting the occurrence of severe hepatitis. By constructing a plasmid coding for mouse Apo A-V protein, we observe whether increasing the intrahepatic expression of Apo A-V could alleviate the mortality and liver pathological changes of mouse with severe hepatitis, so as to clarify the possible role of Apo A-V in severe hepatitis occurrence. By detecting TLR4 signaling pathway and its key molecules expression in severe hepatitis, and activating TLR4 signaling pathway via chemical agonists targeting its key molecules, we would clarify whether the role of Apo A-V in reducing severe hepatitis is correlated to TLR4 signaling pathway. The implementation of this project will help us to identify new indicators of early warning of severe hepatitis occurrence and new targets for the treatment of severe hepatitis, and also provide new ideas to elucidate the mechanism of severe hepatitis.

脂质代谢紊乱是影响慢性肝病患者病情进展的重要因素之一。我们的研究显示：重症肝炎小鼠体内载脂蛋白A-V(Apo A-V)表达明显降低，且在脂质代谢紊乱和慢性炎症相互作用过程中起桥梁作用的TLR4信号通路出现明显异常。 本项目拟通过建立化学性和免疫性两种不同类型的重症肝炎小鼠模型，并结合临床血清标本，观察Apo A-V水平降低是否对重症肝炎的发生具有早期预警作用；构建Apo A-V表达质粒，分析增加肝内Apo A-V表达对重症肝炎小鼠的死亡率及肝组织病理改变的影响，以阐明Apo A-V在重症肝炎发生中的可能作用。进一步通过检测肝组织中TLR4信号通路及关键分子的表达，并利用化学激动剂特异活化TLR4信号传导通路，了解Apo A-V在降低重症肝炎发生中的作用是否与TLR4信号传导通路有关。 本项目实施将有助于寻找预警重症肝炎发生的新指标和治疗重症肝炎的新靶点，并为阐明重症肝炎发生机制提供新思路。

本项目建立了重症肝炎小鼠模型和HBV相关重症肝炎的临床队列，在小鼠模型和临床患者中均观察到ApoA-V表达水平在重症肝炎发生时是明显降低的，且外周血ApoA-V水平可较准确预测重症肝炎患者的远期临床转归。通过增高ApoA-V在小鼠肝组织内的表达，可明显改善LPS和D-GalN诱导的重症肝炎小鼠模型的肝功能指标、减轻肝组织的病理坏死和显著提高重症肝炎小鼠模型的存活率。进一步研究发现，TLR4/Myd88/NF-kB信号通路在重症肝炎小鼠肝组织中明显活化，通过外源性增加ApoA-V表达后，TLR4/Myd88/NF-kB信号通路可被明显抑制，且Apo A-V表达水平高低与TLR4/Myd88/NF-kB信号通路的抑制程度具有一定的相关性，提示ApoA-V在降低重症肝炎发生中的作用机制可能与TLR4信号传导通路有关。本项目研究结果对为寻找预警重症肝炎发生的新指标和治疗重症肝炎的新靶点提供了新的方向，并为阐明重症肝炎发生机制提供了新的思路。