锰抑制乙型肝炎病毒从头感染的分子机制研究

锰(Mn)是机体重要的微量元素，其细胞内代谢涉及精细的细胞生物学调控。乙型肝炎病毒(HBV)感染仍是世界性公共卫生问题，我们前期实验发现低浓度氯化锰能够显著抑制HBV对HepG2-NTCP细胞的从头感染；Mn并不显著激活HepG2细胞中I型干扰素应答，也不能抑制病毒细胞内DNA复制。转录组测序分析显示Mn显著下调AP1M2和TBC1D5基因表达，AP1M2编码蛋白μ1B涉及上皮细胞基底侧膜蛋白分选，而TBC1D5则参与溶酶体功能蛋白Rab7 GTP酶活性的调控。与后者一致的是，我们发现低浓度Mn能够显著地诱导HepG2细胞中溶酶体酸化。本项研究将基于细胞内Mn代谢和转运调控的线索，对Mn抑制HBV感染的分子机制进行全方面解析，着重分析HBV从头感染路径中的受体和受体后病毒学过程，包括内体/溶酶体运输和成熟对HBV早期感染的影响等，以期获取新的认识并探索新的抗病毒治疗靶点。

Manganese (Mn) is an essential trace element required for multiple cellular activities. Mn homostasis is maintained by fine-tuned cellular regulation to prevent an excess accumulation and toxicity. Hepatitis B virus (HBV) infection remains a public heath threat worldwide. Our preliminary study showed that treatment with low dose MnCl2 (10 μM) remarkably inhibited the de novo infection of HBV in HepG2NTCP cells. Mn neither induced production of type I interferon, nor inhibited HBV intracellular replication in HepG2 cells. RNA-Seq analysis suggested that transcription of AP1M2 and TBC1D5 gene was massively downregulated after Mn treatment. AP1M2 gene product μ1B is directly involved in basolateral protein sorting in epithelial cells, while TBC1D5 is known to be a specific GTPase activator of Rab7, a key regulator in endo-lysosomal trafficking. Consistent with the downregulation of TBC1D5, intriguingly, our preliminary data also evidenced significant lysosomal acidification in HepG2 cells after Mn treatment. In this project, we plan a comprehensive study to investigate the anti-HBV activity of Mn, mainly based on an understanding of the cellular metabolic trafficking of Mn and the coordinated regulation. The study will further focus on events occurred at the receptor and post-receptor levels during HBV early infection. The effects of endo/lysosomal maturation and trafficking on the viral infection will be particularly examined. We expect that this study may provide new insight into understanding the early stage of HBV infection, as well as new anti-HBV targets and strategies.