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: 10456292
• 负责人: Severin O Gudima
• 金额: $ 22.7万
• 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 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10456292
• 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 Infection; 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; Persons; 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.

摘要 丁型肝炎病毒（HDV）是B型肝炎病毒（HBV）的一种天然亚病毒，它利用HBV包膜 蛋白质（即，表面抗原，HBsAg）以形成病毒体并通过HBV受体感染肝细胞。257人中 全世界约有2000万人慢性感染HBV，约有2000万人也慢性感染HDV。 HDV仍然是重要的人类病原体。HDV感染引起额外的肝脏发病机制， 加速肝脏疾病，可导致更快速和更频繁的肝硬化，并可增加肝细胞癌的风险。 癌（HCC）。抗HBV药物不能阻断HDV感染。目前临床上尚无直接靶向HDV的药物。 HDV感染的机制远未完全了解，这影响了治疗方案的选择。HDV-HBV 相互作用是复杂的，研究不足。HDV耐药突变株对HDV生命周期的调控 HBV的研究也还不充分。因此，这项建议将研究如何耐药突变， 在用FDA批准的抗HBV药物，拉米夫定，阿德福韦酯， 替比夫定、恩替卡韦或替诺福韦可影响HDV感染。在开放环境中发生的主要突变 HBV聚合酶的阅读框（ORF）可导致相应的耐药突变（DRMs）， HBsAg的重叠ORF DRM被发现在大胞质环（LCL），主要抗原环 (MAL)，HDV结合位点（HDV-BS），和第二，第三和第四跨膜结构域（TMDs II-IV） HBsAg的MAL对于HBV和HDV的感染性至关重要，并且它是HBV和HDV抗原性的主要调节剂， HDV病毒粒子（即，抗HBsAg抗体对病毒体的识别）。HDV-BS介导HBsAg相互作用 在HDV装配过程中与大δ抗原接触。因此，DRM有望调节 HDV装配和感染性，并可能影响HDV-宿主相互作用。我们之前的工作表明， 病毒粒子的感染性、病毒传播和超感染（i）可以决定初始HDV感染是否将被 清除或者它将变得持久（即，慢性）感染，以及（ii）也可能是维持 HDV感染的慢性状态。我们还发现，HBsAg的氨基酸，调节组装的 HDV病毒粒子也可以影响它们的感染性。此外，HDV组装的效率可以大大提高。 影响HDV传播和重复感染。目前对DRM如何调节 HDV的组装和感染性以及抗HBsAg抗体对HDV的识别非常有限。因此，我们认为， 目的1将详细分析携带HBsAg的DRMs如何调节HDV的组装并影响HDV的表达。 HDV病毒体被B型肝炎免疫球蛋白（HBIg）的抗HBsAg抗体识别。此外，委员会认为， 目的2将检查DRM对HDV病毒粒子的感染性的影响。总的来说，该提案将在很大程度上 提高我们对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，预计将 影响HDV感染的结局和HDV致病的程度。