The Role of HBeAg in HBV Persistence

HBeAg 在 HBV 持续存在中的作用

• 批准号: 10066408
• 负责人: Haitao Guo
• 金额: $ 35.89万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-11-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10066408
• 关键词: Role; HBeAg; HBV; Persistence

ABSTRACT Chronic hepatitis B virus (HBV) infection remains a significant public health burden affecting approximately 240 million individuals worldwide and at least 1.2 million in the United States, and is endemic in China where 8-9% of the populations are infected. Chronic hepatitis B (CHB) is one of the leading risk factors of cirrhosis and the deadly liver cancer. Therefore it is important to elucidate the mechanism of HBV persistence and find a cure for chronic hepatitis B. The development of HBV persistence is due to the failure of host immune system to clear the virus infection, and the longevity of the persistent form of HBV DNA genome, which is the covalently closed circular (ccc) DNA in a nuclear minichromosome structure. In this research project, we will set out to elucidate the role of the understudied hepatitis B e antigen (HBeAg) in HBV persistence. HBeAg positivity and high titer reflect the high level of HBV replication and immune tolerance in CHB patients. HBeAg seroconversion is usually considered to be a beneficial milestone and evidence of reduced viral replication. Our preliminary observations revealed the followings: (1) The numbers of circulating monocytic myeloid-derived suppressor cells (mMDSCs) in immune tolerant CHB patients are higher than healthy controls and immune active patients; HBeAg induces the expansion of mMDSCs and the upregulation of immune suppressor molecules including indoleamine 2,3- dioxynase (IDO) in mMDSCs, which in turn inhibit T cell proliferation and IFN-gamma production, suggesting that the HBeAg may induce immune tolerance/suppression through activation of mMDSC; (2) The intracellular HBeAg intermediate (p22), but not the supernatant mature HBeAg, inhibits the activity of interferon-sensitive response element (ISRE) and interferon-stimulated gene (ISG) expression under interferon-alpha (IFN-α) stimulation, suggesting that p22 may blunt IFN signaling to help the virus to evade innate immune response and become resistant to IFN therapy; (3) The nuclear localization of p22 indicates that, reminiscent of the HBeAg homologue HBV core protein which has been shown to bind cccDNA, the p22 may interact with cccDNA minichromosome and regulate its stability and/or transcription. By making use of a battery of HBV-related molecular biology, immunology, biochemistry, and proteomics technologies, and several innovative cell culture tools specially designed for HBeAg and cccDNA studies, we propose to further elucidate the mechanisms of the HBeAg-mMDSC-IDO axis-induced T cell suppression and the intracellular HBeAg-mediated blockage of IFN signaling, and the potential association of nuclear HBeAg with cccDNA and its function will be determined and compared to core protein. The accomplishment of this project will shed light on the mechanism of HBV persistence, and ultimately lead to the development of novel therapeutics to break the virus-induced immune tolerance and reset/reactivate the immune system to clear HBV infection.

抽象的 慢性丙型肝炎病毒（HBV）感染仍然是严重的公共卫生燃烧，影响约240 全球有百万个人，在美国至少120万，在中国是地方性的，那里有8-9％ 人口被感染。慢性乙型肝炎（CHB）是肝硬化的主要危险因素之一 致命的肝癌。因此，重要的是阐明HBV持久性的机制并找到治疗方法 慢性丙型肝炎B。HBV持久性的发展是由于宿主免疫系统未能清除 病毒感染以及HBV DNA基因组的持续形式的寿命，这是共价封闭的 核小体结构中的圆形（CCC）DNA。在这个研究项目中，我们将着手阐明 理解的丙型肝炎抗原（HBEAG）在HBV持久性中的作用。 HBEAG积极性和高滴度 反映CHB患者中HBV复制和免疫耐受性的高水平。 HBEAG血清转换通常是 被认为是一个有益的里程碑和病毒复制减少的证据。我们的初步观察 揭示了以下内容：（1）循环单核细胞衍生的抑制细胞的数量（MMDSC） 在免疫耐受性CHB中，患者高于健康对照组和免疫活性患者。 HBEAG的影响 MMDSC的扩展和免疫抑制分子的上调，包括吲哚美胺2,3-- MMDSC中的二氧化酶（IDO）又抑制T细胞增殖和IFN-Gamma的产生，这表明 HBEAG可以通过激活MMDSC诱导免疫耐受性/抑制作用； （2）细胞内 HBEAG中间体（p22），但没有上清液成熟的hbeag抑制干扰素敏感的活性 反应元件（ISRE）和干扰素刺激的基因（ISG）表达在干扰素-Alpha（IFN-α）下 刺激，表明p22可能会发出信号传导，以帮助病毒逃避先天免疫反应和 对IFN疗法有抵抗力； （3）p22的核定位表明，让人联想到hbeag 同源性HBV核心蛋白已显示与CCCDNA结合，P22可能与CCCDNA相互作用 微型浓度小体并调节其稳定性和/或转录。通过使用与HBV相关的电池 分子生物学，免疫学，生物化学和蛋白质组学技术以及几种创新的细胞培养 我们建议专门为HBEAG和CCCDNA研究设计的工具，我们建议进一步阐明 HBEAG-MMDSC-IDO轴诱导的T细胞抑制和细胞内HBEAG介导的IFN的阻塞 信号传导以及核HBEAG与CCCDNA及其功能的潜在关联将被确定，并且 与核心蛋白相比。该项目的成就将阐明HBV的机制 持久性，并最终导致开发新的疗法以破坏病毒诱导的免疫 耐受性并重置/重新激活免疫系统以清除HBV感染。