Viperin阻断乙肝病毒穿越滋养细胞致宫内感染的作用及机制

Intrauterine infection of hepatitis B virus (HBV) is the causative agent in generation of chronic type B hepatitis in postnatal individuals and high HBV carrying rate in populations. Viruses can induce the host cells to express Viperin, an antiviral protein. Placental trophoblasts have anti-infection immunologic function, but so far no reports about ability of the cells to express Viperin and effect of Viperin against HBV infection are presented. Our earlier study revealed that the Viperin expression level in placental tissue with intrauterine HBV infection was lower than that without intrauterine HBV infection, and HBV could induce the trophoblasts to express Viperin. However, the mechanisms of Viperin expression regulation and effect against HBV infection of the antiviral protein in trophoblasts remain unknown. In this research project, we will use primary trophoblasts, Swan71 trophoblast line and its target gene-knockdown or over-expression cell mutatants as well as Transwell assay, laser confocal microscopy, immunocellchemistry and qRT-PCR to understand the role of trophoblast-expressed Viperin against intrauterine HBV infection. Subsequently, the mechanisms of HBV up-regulating Viperin expression level through TLRs or RLR-mediated IFN-dependent or independent pathway, and the Viperin inducing the expression of IFN-α/β, 2'-5'OAS, PKR and MxA in trophoblasts will be determined. The results of this project will show the high academic and clinical significance.

乙肝病毒（HBV）经胎盘所致宫内感染是出生后慢性乙型肝炎发病、人群HBV高携带率的重要原因。病毒能诱导细胞表达抗病毒蛋白Viperin，滋养细胞具有抗感染免疫功能，但该细胞表达Viperin及其抗HBV作用尚无报道。我们前期研究发现HBV宫内感染组胎盘组织Viperin表达降低、HBV能诱导滋养细胞表达Viperin，但其表达调控及抗HBV机制不明。本项目利用临床标本、原代滋养细胞、Swan71滋养细胞株及Viperin基因沉默及过表达突变株，采用Transwell、激光共聚焦显微镜、免疫组织化学及qRT-PCR等方法，了解滋养细胞表达的Viperin抑制或阻断HBV宫内感染的作用，确定HBV经TLRs及RLR及IFN依赖或不依赖途径上调Viperin表达、Viperin通过诱导IFN-α/β、2'-5'OAS、PKR和MxA表达而发挥抗HBV感染的作用及其机制，具有较高创新性和临床意义。

乙型肝炎病毒（HBV）感染是全球性重大卫生问题。据WHO资料，全球约20亿人曾感染HBV，其中3.5亿发展为慢性乙肝病毒携带者，每年约100万人死于HBV感染相关肝硬化、肝衰竭和原发性肝细胞癌。我国是乙型肝炎高发地区，其中新生儿宫内感染成为人群中HBV携带率居高不下的主要原因之一，研究HBV宫内感染阻断机制对于降低HBV携带率、减少乙型肝炎及相关疾病发病率具有重要意义。病毒能诱导细胞表达抗病毒蛋白Viperin，Viperin有阻断多种病毒感染宿主细胞功能，但滋养细胞表达Viperin及其抗HBV作用尚无报道。我们前期研究发现HBV宫内感染组胎盘组织Viperin表达降低、HBV能诱导滋养细胞表达Viperin，但其表达调控及抗HBV机制不明。本项目利用临床标本、Swan71滋养细胞株及Viperin基因沉默突变株，采用免疫组织化学、Western Blot、Transwell、qRT-PCR、ELISA及电镜等方法，研究了Viperin在滋养细胞抗HBV感染中作用、HBV作用滋养细胞受体、HBV诱导滋养细胞Viperin表达机制及Viperin抗HBV感染机制。研究结果表明：滋养细胞表达的Viperin有下调HBV感染穿越滋养细胞层从而阻断HBV宫内感染的作用，HBV主要经TLRs介导的IFN依赖途径上调Viperin表达，滋养细胞中Viperin对HBV感染滋养细胞中MxA、2’-5’OAS和PKR表达无调控作用。本研究结果作为HBV感染滋养细胞从而发生宫内传播机制基础研究一部分，为进一步研究HBV宫内感染阻断措施提供一定的理论依据。