Mechanism Of Interferon Induction By The Hepatitis C Virus

丙型肝炎病毒诱导干扰素的机制

• 批准号: 7920494
• 负责人: FRANCIS VINCENT CHISARI
• 金额: $ 41.44万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7920494
• 关键词: Acute; Animal Model; Antiviral Agents; Carcinoma; Cell Culture Techniques; Cell physiology; Cells; Characteristics; Chronic Hepatitis; Coculture Techniques; Dendritic Cells; Development; Double-Stranded RNA; Gene Expression; Genes; Genotype; Goals; Hepatitis C; Hepatitis C virus; Hepatocyte; Human; Immune response; In Vitro; Infection; Infectious hepatitides; Interferon-alpha; Interferon-beta; Interferons; Knowledge; Lead; Life; Life Cycle Stages; Liver; Liver Cirrhosis; Liver Failure; Malignant Neoplasms; Mediating; Modeling; Molecular; Molecular Cloning; Nature; Outcome; Pathway interactions; Patients; Peptide Hydrolases; Persons; Primary carcinoma of the liver cells; Process; Production; Public Health; RNA; RNA Viruses; RNA replication; Retinoids; Signal Transduction; Source; System; Therapeutic; Transfer RNA; United States; Viral; Viral Proteins; Virion; Virus; Virus Diseases; Work; base; human TLR7 protein; improved; in vivo; novel; pathogen; peripheral blood; research study; response; socioeconomics; viral RNA; virus host interaction

The long term goal of these studies is to define the host-virus Interactions that occur during hepatitis C virus (HCV) infection with the hope that this knowledge will lead to the discovery of improved therapeutic approaches to this important human pathogen. HCV is a noncytopathic, positive-strand RNA virus that causes acute and chronic hepatitis and hepatocellular carcinoma. Approximately 2-4 million persons are chronically infected by HCV in the USA and 170 million people are chronically infected worldwide, many of whom will die from liver failure and hepatocelluar carcinoma. Elegant in vitro experiments have revealed that HCV strongly inhibits type 1 IFN production in infected cells by blocking the retinoid inducible gene-I (RIG-I)- mediated pathway. In contrast, HCV strongly Induces type 1 IFN responses in the liver despite this evasion mechanism. This discrepancy suggests that HCV might trigger type 1 IFN production in the liver by cells other than infected hepatocytes. In experiments that form the basis of this application, we showed that human peripheral blood plasmacytoid dendritic cells (pDCs) produce large amounts of IFNa and IFNp when they are cocultured with HCV-infected human hepatoma-derived Huh-7 cells. We also showed that IFNproduction correlates strongly with the HCV RNA content of the Huh-7 cells, that it requires direct cell-cell contact between the pDCs and the infected cells, that it is not induced by free infectious HCV particles, and that it is mediated by Toll-like receptor 7 (TLR7) in the pDCs. Importantly, active viral RNA replication by the hepatocyte, not virus particle formation, is required to produce the pDC-activatIng signal, implying that a unique cell-cell RNA transfer mechanism could mediate this response. These unexpected observations help resolve the contradiction between the ability of HCV to induce type 1 IFN in the Infected liver and its ability to block type 1 interferon production by cells it infects. The host apparently avoids this viral evasion strategy via pDC sensing of the infected cells. To my knowledge, this is a novel aspect of the host response to viral infection that deserves to be characterized and more fully understood. In this appiication, therefore, we will define the cellular and molecular characteristics of this exciting new mechanism. In Specific Aim 1. we will identify the molecular nature of the HCV-related signal that activates the pDC, focusing on the viral RNA as the likeliest candidate. In Specific Aim 2, we will examine the cellular mechanisms whereby that signal is produced and how it is transferred to the pDC. In Specific Aim 3, we will explore the extent to which this mechanism is operative in the chronically HCV infected liver.

这些研究的长期目标是确定丙型肝炎期间发生的宿主-病毒相互作用。 病毒（HCV）感染，希望这一知识将导致发现改进的治疗方法， 研究这种重要的人类病原体HCV是一种非致细胞病变的正链RNA病毒， 引起急慢性肝炎和肝细胞癌。大约有200万至400万人 在美国有1.7亿人慢性感染HCV，全世界有1.7亿人慢性感染HCV，许多人 他们将死于肝衰竭和肝细胞癌。优雅的体外实验表明， HCV通过阻断类维生素A诱导基因-I（RIG-I）， 介导的途径。相比之下，HCV强烈诱导肝脏中的1型IFN应答，尽管这种逃避 机制这种差异表明，HCV可能触发1型干扰素的生产在肝脏中的细胞 除了感染的肝细胞。在形成该应用程序基础的实验中，我们表明， 人外周血浆细胞样树突状细胞（pDC）产生大量IFN α和IFN β， 将它们与HCV感染的人肝癌衍生的Huh-7细胞共培养。我们还发现， 与Huh-7细胞的HCV RNA含量密切相关，它需要直接的细胞-细胞 pDC与感染细胞之间的接触，它不是由游离的感染性HCV颗粒诱导的，以及 它由pDC中的Toll样受体7（TLR 7）介导。重要的是，由病毒RNA复制的活性， 产生pDC激活信号需要肝细胞，而不是病毒颗粒的形成，这意味着 独特的细胞-细胞RNA转移机制可以介导这种反应。这些意想不到的观察有助于 解决HCV在感染的肝脏中诱导1型IFN的能力与其在感染的肝脏中诱导IFN的能力之间的矛盾， 阻断其感染的细胞产生1型干扰素。宿主显然通过以下途径避免这种病毒逃避策略： 感染细胞的pDC感应。据我所知，这是宿主对病毒的反应的一个新方面， 感染，值得被描述和更充分地理解。 因此，在本申请中，我们将定义这种令人兴奋的新机制的细胞和分子特征。具体目标1。我们将鉴定激活pDC的HCV相关信号的分子性质，重点关注病毒RNA作为最可能的候选者。在具体目标2中，我们将研究信号产生的细胞机制以及它如何转移到pDC。在具体目标3中，我们将探讨这种机制在慢性HCV感染肝脏中的作用程度。