HDV spread during chronic infection as a novel target for antiviral intervention

慢性感染期间 HDV 传播作为抗病毒干预的新目标

• 批准号: 8516456
• 负责人: Severin O Gudima
• 金额: $ 21.29万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8516456
• 关键词: Academy; Acute; American; Animals; Anti-HIV Agents; Antineoplastic Agents; Antiviral Agents; Attention; Basic Science; Binding; Biological Assay; Brazil; Cells; China; Chronic; Chronic Hepatitis; Chronic Hepatitis B; Country; Data; Disadvantaged; Drug Targeting; Elements; Europe; Event; Famciclovir; Future; Genome; Goals; Health; Helper Viruses; Hepadnaviridae; Hepatitis B; Hepatitis B Vaccines; Hepatitis B Virus; Hepatitis C; Hepatitis Delta Virus; Hepatitis delta Antigens; Hepatocyte; Human; Immigrant; Immune; In Vitro; Incidence; India; Individual; Infection; Institute of Medicine (U.S.); Interferon-alpha; Interferons; Intervention; Iran; Lamivudine; Lead; Life Cycle Stages; Liver; Liver diseases; Maintenance; Malignant neoplasm of liver; Measures; Medical; Messenger RNA; Modeling; Mongolia; Mutation; Nature; Open Reading Frames; Pan Genus; Pathogenesis; Peptides; Pharmaceutical Preparations; Predictive Factor; Prevention approach; Primary carcinoma of the liver cells; Production; Replication Initiation; Reporting; Research; Resistance; Risk; Risk Factors; Role; South American; Staging; Tajikistan; Telbivudine; Tenofovir; Testing; Therapeutic; Time; Transcript; Travel; Tunisia; United States; Vietnam; Viral Proteins; Virion; Virus; Virus Assembly; Virus Diseases; Virus Receptors; Virus Replication; Work; adefovir; analog; anti-hepatitis B; base; entecavir; env Gene Products; farnesylation; hepatitis B virus L protein; hepatitis B virus P protein; improved; in vivo; inhibitor/antagonist; migration; mortality; mutant; novel; pathogen; receptor binding; reconstitution; response; viral DNA; viral RNA; virus envelope

DESCRIPTION (provided by applicant): Chronic hepatitis B virus (HBV) infection is the main cause of hepatocellular carcinoma (HCC) worldwide and is responsible for 50-80% of all HCC cases. Of the 400 million current chronic HBV carriers, about 65 million will die from an advanced liver disease or HCC. Concomitant infection with hepatitis delta virus (HDV) usually enhances liver pathogenesis. HDV, a subviral agent of HBV, always co-exists with its helper HBV in nature and uses HBV envelope proteins to form the virions and infect hepatocytes via HBV receptor(s). The number of chronic HDV carriers worldwide is about 20 million. HDV is a significant human pathogen. Chronic carriers of HBV/HDV have 3-fold increased risk of HCC incidence, and develop HCC approximately 14 years earlier than carriers of HBV only. Persistent HDV replication is a predictive factor for liver-associated mortality. Currently, there s no therapy against HDV, and a number of anti-HBV drugs do not block HDV infection. Carriers of HBV and HDV cannot be helped by HBV vaccine and desperately need novel targets for medical interventions and new treatments. We propose to exploit the uniqueness of the mechanism of chronic HDV infection in a search for a novel target for antiviral intervention. Briefly, despite studies suggesting that cell-to-cell spread of a helper hepadnavirus (HBV) during chronic infection is an unlikely event, the occurrence of the spread of either HBV or HDV during chronic infections was neither demonstrated nor disproved. However, our analysis of HDV mRNA in transfected cells and in the liver of transiently infected animal suggests that in absence of the spread, HDV genomes accumulate mutations in the open reading frame (ORF) for delta antigen (?Ag) (the only HDV protein and is essential for HDV replication) that preclude self-sustained HDV replication. Therefore, this application will test the hypothesis that HDV must rely on continuous cell-to-cell spread to maintain chronic infection. Our goal is to determine if HDV spread is a valid novel target for intervention against chronic HDV infection. We will conduct in vitro and in vivo HDV infections either in the presence or in the absence of the spread. To analyze three critical aspects of HDV spread, we propose to: (i) assay the ?Ag ORF for mutations that make ?Ag unable to support HDV replication (Aim 1), (ii) measure the replication capacity of HDV genomes (Aim 1), and (iii) compare infectivities of HDV virions early and late in chronic infection (Aim 2). We will determine for the first time whether, in infected hepatocytes in the absence of spread, HDV genomes lose the ability for self-sustained replication due to mutations in ?Ag ORF, and whether ongoing spread selects against the genomes encoding non-functional ?Ags. Overall, this study will greatly advance our understanding of the mechanism of chronic HBV/HDV infection, and will likely (i) identify HDV spread as a factor of pathogenesis and HCC risk, and (ii) facilitate the use of inhibitors of the assembly and entry as novel antivirals for HDV carriers. Furthermore, if HBV spread during chronic infection is demonstrated, virus entry inhibitors will work for HBV carriers regardless of HBV mutants resistant to current anti-HBV drugs.

描述（由申请人提供）：慢性丙型肝炎病毒（HBV）感染是全球肝细胞癌（HCC）的主要原因，占所有HCC病例的50-80％。在当前4亿次慢性HBV载体中，约有6500万辆将死于晚期肝病或HCC。与乙型肝炎病毒（HDV）同时感染通常会增强肝脏发病机理。 HDV是HBV的副病毒药物，始终与其自然界的辅助HBV共存，并使用HBV包膜蛋白形成病毒体并通过HBV受体感染肝细胞。全球慢性HDV运营商的数量约为2000万。 HDV是一种重要的人类病原体。 HBV/HDV的慢性载体的HCC发病率增加了3倍，并且仅比HBV携带者早14年发展HCC。持续的HDV复制是肝相关死亡率的预测因素。目前，没有针对HDV的治疗方法，许多抗HBV药物不会阻止HDV感染。 HBV和HDV的载体无法通过HBV疫苗帮助，迫切需要新的目标来进行医疗干预和新治疗。我们建议在寻找新型抗病毒干预靶标时利用慢性HDV感染机制的独特性。简而言之，尽管研究表明，在慢性感染过程中，辅助肝病病毒（HBV）的细胞间传播是不太可能的事件，但在慢性感染过程中HBV或HDV的扩散均未被证明也没有被证明也不反应。但是，我们对转染细胞中HDV mRNA和瞬时感染动物的肝脏中的分析表明，在没有扩散的情况下，HDV基因组在开放阅读框架（ORF）中积累突变（ORF），用于Delta抗原（？Ag）（唯一的HDV蛋白对于HDV复制至关重要），该复制排除了自我维持的HDV复制。因此，该应用将测试HDV必须依靠连续细胞间扩散以维持慢性感染的假设。我们的目标是确定HDV差异是否是针对慢性HDV感染进行干预的有效新目标。我们将在存在或没有扩散的情况下在体外和体内HDV感染进行。为了分析HDV传播的三个关键方面，我们建议：（i）测定ag orf，以使Ag无法支持HDV复制的突变（AIM 1），（ii）测量HDV基因组的复制能力（AIM 1 ），（iii）比较慢性感染的早期和后期HDV病毒体的感染（AIM 2）。我们将首次确定在没有扩散的情况下感染的肝细胞中，HDV基因组失去了由于ag orf突变而引起的自我维持复制的能力，以及持续的扩散是否可以针对编码非功能的基因组进行选择。 。总体而言，这项研究将大大提高我们对慢性HBV/HDV感染机制的理解，并可能（i）（i）确定HDV扩散是发病机理和HCC风险的因素，以及（ii）促进组装和组装抑制剂的使用作为HDV载体的新型抗病毒药物。此外，如果证明HBV在慢性感染期间扩散，则无论HBV突变体对当前抗HBV药物具有抗性，病毒进入抑制剂都将用于HBV载体。