宿主SART1基因调控干扰素抗HBV效应及其作用机制研究

Response rate of IFN anti-HBV treatment is not high, the regulation mechanism on IFN anti- HBV effect is not fully elucidated. Literature reported that alternative splicing gene SART1 can effects of IFN anti-HCV gene expression, but SART1 gene research related to HBV has not been reported. Recent literature reported that IFN induced antiviral gene APOBEC3 exerted an effect on cccDNA( HBV replication template )degradation, and alternative splicing variants of APOBEC3 family were observed in previous study. The applicant has found that SART1 baseline levels in peripheral blood mononuclear cells (PBMC) and liver tissue from responders was significantly higher than that of non responders with HBV IFN therapy. IFN induced antiviral gene APOBEC3A, 3B, 3C and 3G significantly lowered when silencing SART1 in HBV replication cell models treated with IFN, followed by the change of interferon anti-HBV effect. Put forward the scientific hypothesis: SART1 is a key regulatory molecule in the IFN treatment of HBV, SART1 can regulate IFN anti-HBV effect by regulating APOBEC3 gene expression.Based on the previous meaningful work, this project aims to confirm regulation of IFN anti-HBV effect by host SART1 in different cell model and HBV clinical samples and explore its specific mechanism, then obtaining potential therapeutic target.

乙型肝炎抗病毒治疗中，干扰素应答率不高，干扰素抗HBV的调控机制亦未完全阐明。文献报道可变剪切因子SART1可以影响干扰素抗HCV相关基因的表达，但在HBV中的研究还未见报道。新近文献报道干扰素诱生的抗病毒基因APOBEC3对HBV复制模板cccDNA有降解作用，APOBEC3家族亦存在可变剪切体。申请人预实验发现：干扰素治疗慢乙肝有应答患者外周血单个核细胞和肝组织中基线SART1水平显著高于无应答患者。乙肝细胞模型中沉默SART1后用干扰素处理细胞，APOBEC3A、3B、3C和3G mRNA水平下调，干扰素抗病毒效果明显改变。据此提出科学假说：SART1是乙肝干扰素治疗中的关键调控分子，SART1可以通过调控APOBEC3基因的表达进而影响干扰素抗HBV效应。本项目拟在预实验基础上，在细胞模型和临床样本中确证SART1调控干扰素抗HBV效应并探讨其具体机制，以期获得潜在治疗靶点。

慢性乙型肝炎抗病毒治疗应答率不高，干扰素抗HBV的调控机制亦未完全阐明。本项目拟研究可变剪切基因SART1调控干扰素抗HBV效应并探讨其具体机制，以期获得潜在治疗靶点。我们研究发现SART1自身不受干扰素调控，而下调SART1基因导致经典的干扰素JAK--STAT通路中ISRE元件活性减弱，抗病毒蛋白MxA，2,5-OAS, PKR均被下调，干扰素抗HBV效应被抑制。同时在HBV感染细胞系中沉默SART1，内源性抗病毒蛋白MxA，ISG15均明显下调，HBV病毒复制显著增强。进一步研究发现SART1与巨噬细胞的分化密切相关，下调SART1导致巨噬细胞向M1表型分化，提示SART1与天然免疫有相关性。通过临床样本和体外细胞实验我们发现感染过程中HBV对SART1具有激活作用，SART1自身亦对HBV的复制有抑制作用，其机制是通过抑制HBV前基因组RNA所实现。我们的研究明确了影响干扰素疗效的宿主因素以及病毒-宿主-天然免疫之间的关联，为临床慢性乙型肝炎抗病毒治疗提供了新的参考和思路，以期改善治疗效果和远期预后。