Regulation of the life cycle of HDV by the drug resistance mutations of HBV

乙型肝炎病毒耐药突变对丁型肝炎病毒生命周期的调控

• 批准号: 10285584
• 负责人: Severin O Gudima
• 金额: $ 19.25万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-23 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10285584
• 关键词: Address; Affect; Amino Acids; Antibodies; Area; Binding; Binding Sites; Biological Assay; Cells; Chronic; Chronic Hepatitis D; Cirrhosis; Clinic; Complex; Data; Drug resistance; FDA approved; Genome; Genotype; HBV Genotype; HepG2; Hepatitis B; Hepatitis B Antibodies; Hepatitis B Surface Antigens; Hepatitis B Virus; Hepatitis B virus Pol Protein; Hepatitis D; Hepatitis Delta Virus; Hepatitis delta Antigens; Hepatocyte; Human; Immune response; Immunofluorescence Immunologic; Immunoglobulins; In Vitro; Individual; Lamivudine; Lead; Life Cycle Stages; Liver; Liver diseases; Location; Maintenance; Mediating; Mutate; Mutation; Open Reading Frames; Outcome; Pathogenesis; Pharmaceutical Preparations; Plasma; Plasmids; Polymerase Gene; Primary Infection; Primary carcinoma of the liver cells; Property; Regulation; Research; Risk; Role; Site; Surface Antigens; Telbivudine; Tenofovir; Time; Transfection; Transmembrane Domain; Ursidae Family; Variant; Viral; Viral Genome; Viral Pathogenesis; Viral Proteins; Virion; Virus; Virus Assembly; Virus Diseases; Virus Receptors; Work; adefovir; anti-hepatitis B; base; chronic infection; entecavir; env Gene Products; human pathogen; mutant; resistance mechanism; resistance mutation; superinfection; vector; viral RNA; virus host interaction

Abstract Hepatitis delta virus (HDV) is a natural sub-viral agent of hepatitis B virus (HBV), which uses HBV envelope proteins (i.e., surface antigen, HBsAg) to form the virions and infect hepatocytes via HBV receptor. Out of 257 million people chronically infected with HBV worldwide about 20 million are also chronically infected with HDV. HDV remains a significant human pathogen. HDV infection causes additional liver pathogenesis, and can accelerate liver disease, can cause more rapid and frequent cirrhosis, and can elevate risk of hepatocellular carcinoma (HCC). Anti-HBV drugs do not block HDV infection. No drugs directly targeting HDV exist in clinic. Mechanism of HDV infection is far from being fully understood, which affects the treatment options. HDV-HBV interactions are complex and under-studied. The regulation of HDV life cycle by the drug-resistant mutants of HBV remains under-studied as well. Therefore, this proposal will examine how the drug resistance mutations in HBV genome selected during the treatment with FDA-approved anti-HBV drugs, lamivudine, adefovir, telbivudine, entecavir or tenofovir, can influence HDV infection. The primary mutations that occur in the open reading frame (ORF) of HBV polymerase can lead to the corresponding drug resistance mutations (DRMs) in the overlapping ORF for HBsAg. DRMs were found in the large cytosolic loop (LCL), major antigenic loop (MAL), HDV-binding site (HDV-BS), and second, third and fourth transmembrane domains (TMDs II-IV) of HBsAg. MAL is critical for infectivity of HBV and HDV, and it is a major regulator of the antigenicity of HBV and HDV virions (i.e., recognition of the virions by anti-HBsAg antibodies). HDV-BS mediates HBsAg interactions with the large delta antigen during HDV assembly. Thus, DRMs are expected to regulate the mechanisms of the HDV assembly and infectivity, and could affect HDV-host interactions. Our previous work suggested that the infectivity of the virions, virus spread and super-infection (i) could determine if initial HDV infection will be cleared or it will become persistent (i.e., chronic) infection, and (ii) also could be critical for the maintenance of the chronic state of HDV infection. We also found that amino acids of HBsAg that regulate the assembly of HDV virions can influence their infectivity as well. Furthermore, the efficiency of HDV assembly can greatly affect HDV spread and super-infection. Current understanding of the mechanisms how DRMs regulate the assembly and infectivity of HDV, and recognition of HDV by anti-HBsAg antibodies is very limited. Therefore, Aim 1 will analyze in detail how HBsAg bearing DRMs can regulate the assembly of HDV and affect the recognition of HDV virions by anti-HBsAg antibodies of the hepatitis B immune globulin (HBIg). Furthermore, Aim 2 will examine the effects of DRMs on the infectivity of HDV virions. Overall, the proposal will considerably advance our understanding of the mechanisms of how the drug-resistant mutants of HBV influence the HBV- HDV interactions, and regulate the assembly, infectivity and antigenicity of HDV virions, which is expected to influence the outcomes of HDV infection and the extent of HDV pathogenesis.

抽象的 丁型肝炎病毒 (HDV) 是乙型肝炎病毒 (HBV) 的天然亚病毒因子，它使用 HBV 包膜 蛋白质（即表面抗原，HBsAg）形成病毒粒子并通过 HBV 受体感染肝细胞。共 257 个 全球有 100 万人慢性感染 HBV，其中约 2000 万人也慢性感染 HDV。 HDV 仍然是一种重要的人类病原体。 HDV 感染会引起额外的肝脏发病机制，并且可以 加速肝脏疾病，可能导致更快、更频繁的肝硬化，并可能增加肝细胞性心脏病的风险 癌（HCC）。抗乙型肝炎病毒药物不能阻止丁型肝炎病毒感染。临床上尚无直接针对 HDV 的药物。 HDV 感染机制远未完全了解，这影响了治疗选择。丁型肝炎病毒 相互作用是复杂的且尚未得到充分研究。丁型肝炎病毒耐药突变体对生命周期的调控 乙型肝炎病毒的研究也尚未充分。因此，该提案将研究耐药性突变是如何发生的。 在 FDA 批准的抗 HBV 药物拉米夫定、阿德福韦、 替比夫定、恩替卡韦或替诺福韦可以影响 HDV 感染。发生在开放环境中的主要突变 HBV聚合酶的阅读框（ORF）可导致相应的耐药突变（DRM） HBsAg 的重叠 ORF。在大胞质环 (LCL)、主要抗原环中发现了 DRM (MAL)、HDV 结合位点 (HDV-BS) 以及第二、第三和第四跨膜结构域 (TMDs II-IV) 乙肝表面抗原。 MAL 对 HBV 和 HDV 的感染性至关重要，并且是 HBV 和 HDV 抗原性的主要调节因子。 HDV 病毒体（即抗 HBsAg 抗体识别病毒体）。 HDV-BS 介导 HBsAg 相互作用 HDV 组装过程中与大 delta 抗原结合。因此，DRM 有望调节以下机制： 丁型肝炎病毒的组装和感染性，并可能影响丁型肝炎病毒与宿主的相互作用。我们之前的工作表明 病毒颗粒的传染性、病毒传播和重复感染 (i) 可以决定最初的丁型肝炎病毒感染是否会发生 清除，否则将成为持续性（即慢性）感染，并且（ii）对于维持 HDV 感染的慢性状态。我们还发现 HBsAg 的氨基酸可以调节 丁型肝炎病毒粒子也会影响其传染性。此外，HDV 装配的效率可以大大提高 影响 HDV 传播和重复感染。目前对 DRM 调节机制的理解 HDV 的组装和感染性以及抗 HBsAg 抗体对 HDV 的识别非常有限。所以， 目标1将详细分析带有HBsAg的DRM如何调节HDV的组装并影响 乙型肝炎免疫球蛋白 (HBIg) 的抗 HBsAg 抗体识别 HDV 病毒颗粒。此外， 目标 2 将检查 DRM 对 HDV 病毒颗粒感染性的影响。总体而言，该提案将大大 增进我们对 HBV 耐药突变体如何影响 HBV 的机制的理解 HDV 相互作用，并调节 HDV 病毒粒子的组装、感染性和抗原性，这有望 影响 HDV 感染的结果和 HDV 发病机制的程度。