顺铂诱导HBV再激活和肝细胞损伤的分子机制研究

With the numerous clinical research performed in the past 10 years, hepatitis due to reactivation of HBV is now a well-recognized complication in patients with chronic HBV infection receiving cytotoxic or immunosuppressive therapy. Reactivation of HBV is a well-characterized syndrome marked by the abrupt reappearance or rise of hepatitis B virus (HBV) DNA in the serum of a patient with previously inactive or resolved HBV infection. Reactivation can lead to clinically apparent acute hepatitis, which can be severe and result in acute liver failure and death. Nevertheless, the molecular mechanism relating to reactivation caused by cytotoxic chemotherapy such as cisplatin still remains unknown. Our preliminary data indicated that cisplatin upregulated HBV core promoter activity and sharply enhanced virus replication by inducing PGC-1α and HNF4α expression.Also,cisplatin induced non-enveloped capsids particle release from HBV-replicating cells. Based on these data, we hypothesized that chemotherapeutic regimens, such as cisplatin, may directly enhance virus replication and induce capsids egress, thus leading to acute liver injury (ALI) due to core antigen-induced immune response. In this study, HBV-replicating cells, HBV-transgenic mice and hydrodynamic HBV animal model will be used to investigate the molecular mechanism that cisplatin-induced abrupt increase in HBV replication. By Microarray, immunohistochemistry and core-antibody blocking techniques, we will further verified that cisplatin-promoted capsids release and subsequently triggered immune response, especially B cell response, is the leading cause of ciplatin-induced ALI. Our studies will elucidate the molecular mechanism of reactivation of HBV, and will provide new insights into HBV-associated pathogenesis and may be helpful in developing an effective treatment against HBV replication.

近年来多项临床实验证实顺铂等化疗药物诱导HBV再激活，病毒复制增强，伴随急性肝功能损伤，病死率增加。HBV再激活的分子机制至今不明。课题组前期实验发现：顺铂上调HBV复制相关转录因子HNF4α和PGC-1α的表达，增强病毒核心启动子活性，在转录水平增强HBV复制；顺铂诱导HBV复制细胞核心颗粒的直接释放。基于上述实验结果，我们提出"顺铂等化疗药物直接上调HBV的复制水平，诱导病毒核心颗粒直接释放，是造成急性肝损伤的主要分子基础"这一科学假说。本课题将通过Real-time PCR、ChIP等实验探索顺铂诱导HBV再激活的分子机制；在HBV感染动物模型验证顺铂引起的急性肝损伤，采用基因表达谱芯片、免疫组化、核心抗体阻断等实验证实顺铂诱导病毒核心颗粒的释放是急性肝损伤发生的分子基础。项目的实施将化疗药物诱导的"HBV再激活"临床现象与病毒复制等基础研究紧密结合，力图解析该现象发生的分子机制。

近年来多项临床实验证实顺铂等化疗药物诱导HBV再激活，病毒复制增强，伴随急性肝功能损伤，病死率增加。HBV再激活的分子机制至今不明。课题组前期实验发现：顺铂上调HBV复制相关转录因子HNF4α和PGC-1α的表达，增强病毒核心启动子活性，在转录水平增强HBV复制；顺铂诱导HBV复制细胞核心颗粒的直接释放。基于上述实验结果，我们提出“顺铂等化疗药物直接上调HBV的复制水平，诱导病毒核心颗粒直接释放，是造成急性肝损伤的主要分子基础”这一科学假说。本课题在分子水平研究了顺铂引起HBV再激活的机制，发现了顺铂为代表的化疗药物可以直接导致HBV复制再激活，并在HBV转基因小鼠和HBV水动力感染模型中证实。具体的机制：1）顺铂通过激活ERS-PGC-1α轴促HBV复制；2）顺铂通过ROS上调JNK/p-38、抑制AKT/mTOR信号诱导自噬促进HBV复制。项目的实施丰富了我们对顺铂促进HBV复制的机制认识，从分子水平解析了 HBV 潜伏感染的本质，为更好地寻找调控 HBV 复制的转录因子、探索 HBV 复制增强后引起肝细胞损伤的分子机制提供了新的思路。