Characterization of host restriction factors interfering with replication and persistency of hepatitis B and D viruses

干扰乙型肝炎和丁型肝炎病毒复制和持久性的宿主限制因素的表征

• 批准号: 430621923
• 负责人: Professor Dr. Dieter Glebe
• 金额: --
• 依托单位: Institut für Medizinische Virologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/430621923?language=en
• 关键词: Characterization; host; restriction; factors; interfering

Infections with Hepatitis B virus (HBV), and coinfections with Hepatitis D virus (HDV) are still a major global health threat. Both viruses can lead to acute and chronic (co-)infections of the liver. Over 250 million people are chronically infected with HBV and at least 11 million people are chronically (co-)infected with HDV, causing ca. 1 million casualties annually due to fatal clinical outcomes. While a protective vaccine is available that can prevent infection with both viruses, there is currently no cure for chronically HBV-infected patients, and direct anti-HDV therapies are not yet fully developed. One of the greatest obstacles to a cure for chronic HBV infection is the covalently closed circular DNA (cccDNA) that HBV uses as a stable and persistent reservoir in the nucleus of infected hepatocytes. HDV, as a defective RNA-virus, requires constant support from HBV in the form of surface proteins (HBsAg) for envelopment and secretion of virions. While HBV has developed elaborate, but not yet sufficiently studied mechanisms to remain a “stealth virus”, HDV activates innate immune responses in HDV/HBV infected cells that leads to suppression of HBV replication. Since cellular sensing mechanisms and pathways of innate immunity in chronic HBV/HDV infections still remain elusive, the proposed project aims to elicit the role of individual, downstream effector host proteins that can interfere with viral replicative cycles during HBV/HDV persistence. To pursue this goal, we will directly activate transcription of selected host target genes using a smart gain-of-function technique (CRISPRa) to systematically study the effects of activated cellular genes on replication and persistency of HBV and HDV in vitro. In detail, we will (1) investigate effects of host effector proteins on HBV and HDV infection and replication and (2) analyze persistence of HDV genomes in infected cells with 88 relevant predefined host-genes; (3) distinguish direct vs. indirect (regulatory) effect of activated host genes on HBV/HDV replication; and (4) compare effects of the host-cell response on replicating HBV cccDNA and its methylation profiles of most relevant HBV genotypes.Overall, the proposed project will provide important basic insights into the intracellular interaction of HBV and HDV with their host cells; determine the potential resistance of viral genomes to antiviral factors, and improve our understanding of the innate immune response to chronic viral hepatitis.

B型肝炎病毒（HBV）感染和丁型肝炎病毒（HDV）合并感染仍然是全球主要的健康威胁。这两种病毒都可以导致急性和慢性（合并）肝脏感染。超过2.5亿人慢性感染HBV，至少有1100万人慢性（共）感染HDV，导致约1000万人死亡。每年有100万人因致命的临床结果而伤亡。虽然有一种保护性疫苗可以预防这两种病毒的感染，但目前还没有治愈慢性HBV感染患者的方法，而且直接的抗HDV疗法尚未完全开发。治愈慢性HBV感染的最大障碍之一是共价闭合环状DNA（cccDNA），HBV将其用作受感染肝细胞核中稳定和持久的储库。HDV作为一种缺陷型RNA病毒，需要HBV以表面蛋白（HBsAg）的形式持续支持，以抑制和分泌病毒体。虽然HBV已经开发出复杂的但尚未充分研究的机制以保持“隐形病毒”，但HDV激活HDV/HBV感染细胞中的先天免疫应答，导致HBV复制的抑制。由于慢性HBV/HDV感染中先天免疫的细胞传感机制和途径仍然难以捉摸，因此拟议的项目旨在引发可以在HBV/HDV持续期间干扰病毒复制周期的个体下游效应宿主蛋白的作用。为了实现这一目标，我们将使用智能功能获得技术（CRISPRa）直接激活选定的宿主靶基因的转录，以系统地研究激活的细胞基因对HBV和HDV体外复制和持续存在的影响。具体而言，我们将（1）研究宿主效应蛋白对HBV和HDV感染和复制的影响，（2）用88个相关预定义的宿主基因分析HDV基因组在感染细胞中的持久性;（3）区分直接与间接激活的宿主基因对HBV/HDV复制的（调节）作用;和（4）比较宿主细胞应答对复制HBV cccDNA及其最相关HBV基因型的甲基化谱的影响。总体而言，拟议的项目将为HBV和HDV与其宿主细胞的细胞内相互作用提供重要的基本见解;确定病毒基因组对抗病毒因子的潜在抗性，并提高我们对慢性病毒性肝炎先天免疫反应的理解。