IFN-λ通过JAK-STAT信号通路抑制WHV在土拨鼠肝细胞内复制及其机制

Chronic infection with hepatitis B virus (HBV) is associated with significant liver disease and is therefore an important public health problem. The current standard-of-care therapy for chronic hepatitis B (CHB) consists of a combination of interferon-α(IFN-α) and nucleotide/nucleoside analogs. Although IFN-α therapy effectively generates a sustained viral response in approximately 40% of treated individuals, it is associated with significant hematological and neurological side effects. A new family of IFN-related proteins (IFN-λ1, 2, and 3; or alternately, IL-29, 28A, 28B, respectively) possesses antiviral properties that may make these cytokines superior to IFN-α for antiviral therapy. The potential clinical importance of IFN-λ as a novel antiviral therapeutic agent is already apparent. In addition, preclinical studies by several groups indicate that IFN-λ may also be useful as a potential therapeutic agent for other clinical indications, including certain types of chronic hepatiti C virus infection. Although the inhibitory effects of IFN-λ have been observed against a wide variety of viruses, the molecular mechanisms behind these activities have not been fully described. In this research, a scientific hypothesis was given: IFN-λ alone could inhibit HBV replication by JAK-STAT signal transduction molecular mechanism in vivo. We will investigate the molecular mechanism of IFN-λ inhibit HBV replication through using woodchuck model. In this research, we also will investigate if a more prolonged STAT phosphorylation in JAK-STAT signaling pathway IFN-λ of enhance antiviral effect of interferon, and when IL28Rα,one of special receptor subunit of IFN-λ, was blocked expression, the IFN-λ anti-WHV effect how to change. This research would be useful for clinical therapy of IFN-λ for patients with chronic hepatitis B virus infection in future.

α干扰素已广泛用于慢性乙型肝炎的治疗，但其应答率仅40%左右且对部分患者有副作用。新的Ⅲ型λ干扰素具有抗病毒和免疫调节作用，我们的前期研究发现λ干扰素体外较强地抑制了HBV复制，且λ干扰素作用于肝细胞后胞内JAK-STAT 信号通路中关键分子STAT1/2磷酸化时间明显延长，但其肝内抗HBV机制尚不清楚，亟待在合适的动物模型上深入研究加以阐明。基于此，本研究拟用在HBV抗病毒机制研究中具有独特优势的土拨鼠/旱獭模型进行如下研究：1）WHV慢性感染对土拨鼠肝细胞内λ干扰素 JAK-STAT信号通路完整性的影响；2）RNAi阻断λ干扰素特异性受体IL28Rα，分析其在调节干扰素抗病毒中的作用机制；3）结合土拨鼠模型和原代肝细胞模型探讨IFN-λ信号通路抗病毒作用机制及免疫调节作用。本研究项目的意义是明确λ干扰素抗WHV复制的分子机制，为临床λ干扰素治疗慢性乙肝的提供重要的理论和实验依据。

临床治疗慢性乙型肝炎主要是α干扰素和核苷（酸）类似物，α干扰素应答率仅40%左右且有副作用。新的Ⅲ型λ干扰素具有抗病毒和免疫调节作用，我们的前期研究发现λ干扰素体外较强地抑制了HBV复制，但其肝内抗HBV机制尚不清楚，亟待在合适的动物模型上深入研究加以阐明。本研究在HBV复制细胞模型和HBV复制小鼠模型进行了λ干扰素抗HBV复制机制研究。证实IFN-λ在HBV复制体外和体内模型上有效抑制了HBV的复制，包括HBsAg、HBeAg、HBV DNA水平，干扰素信号通路中STAT1/STAT2磷酸化水平延后，而且研究发现IFN-λ通过APOBEC3途径有效降解了HBV复制的关键复制中间体HBV共价闭合环状DNA（HBV cccDNA）。本研究结果为λ干扰素进入临床治疗慢性乙肝的提供重要的理论和实验依据。