Tim-3-mediated IL-12 dysregulation in antiviral responses to HCV infection

Tim-3 介导的 HCV 感染抗病毒反应中 IL-12 失调

• 批准号: 8302086
• 负责人: Zhi Q. Yao
• 金额: $ 31.76万
• 依托单位: EAST TENNESSEE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-10 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8302086
• 关键词: Affect; Anabolism; Antiviral Agents; Antiviral Response; Antiviral Therapy; Apoptosis; Biological Models; CD8-Positive T-Lymphocytes; CD8B1 gene; Cell Differentiation process; Cells; Cessation of life; Chronic; Chronic Hepatitis C; Clinical; Coculture Techniques; Cytokine Inducible SH2-Containing Protein; Data; Dendritic Cells; Epidemic; Functional disorder; Genetic Transcription; Genotype; Goals; Hepatitis C; Hepatitis C virus; Hepatocyte; Human; Immune; Immune response; Immunity; Immunoglobulins; Immunomodulators; Immunotherapy; Impairment; Individual; Infection; Inflammatory; Interferons; Interleukin-12; Lead; Link; Liver; Mediating; MicroRNAs; Modeling; Mucins; Natural Immunity; Outcome; Patients; Play; Production; Regulation; Role; Signal Pathway; Signal Transduction; System; T cell response; T-Lymphocyte; Tertiary Protein Structure; Testing; Th1 Cells; Th2 Cells; Toll-like receptors; Translations; Up-Regulation; Vaccines; Viral; Viral Antigens; Virus; Virus Diseases; Virus Replication; adaptive immunity; base; cohort; combat; cytokine; exhaustion; global health; improved; macrophage; monocyte; novel; novel strategies; programs; receptor; response; tool; translational approach; treatment response; virus core; virus host interaction

DESCRIPTION (provided by applicant): Hepatitis C virus (HCV) is remarkable at disrupting human immunity to establish chronic infection; it is a global health problem with limited treatment options and no available vaccine. The mechanisms by which the virus persists in the majority of infected liver by overcoming the host innate to adaptive immunity is currently unclear, partly due to our incomplete understanding of HCV-host interactions that lead to this immune disruption. We have previously demonstrated that chronic HCV infection leads to immunodysregulation mediated through up- regulation of negative immunomodulators, including programmed death-1 (PD-1), suppressor of cytokine signaling-1 (SOCS-1), and most recently, T cell immunoglobulin and mucin domain protein-3 (Tim-3). While Tim-3 has been shown to play a critical role in T cell exhaustion during chronic viral infections, its expression and function on innate immune cells in HCV persistence and antiviral responses remain unknown. We have recently discovered that Tim-3 plays a pivotal role in negative regulation of Toll-like receptor (TLR)-mediated innate immune responses, being up-regulated on monocytes/macrophages (M/M?) isolated from chronically HCV-infected individuals and healthy M/M??co-cultured with HCV-expressing hepatocytes. Importantly, blocking Tim-3 signaling restores the expression of IL-12, a key pro-inflammatory cytokine linking innate to adaptive immune responses. This novel observation suggests that the inability to clear virus in chronically HCV-infected hosts may be a function of a Tim-3-mediated impairment of innate immunity, with subsequent dysfunction of adaptive immune responses. We thus hypothesize that HCV-mediated Tim-3 up-regulation on M/M??plays a central role in innate immune and IL-12 dysregulation, such that blockade of Tim-3 signaling in M/M??may rescue impaired antiviral immune responses. To test this hypothesis, we will carry out the following specific aims: 1) Define the role of Tim-3 up-regulation on M/M? from HCV-infected patients following antiviral therapy with defined outcomes, comparing with those naturally resolved HCV infection or healthy subjects, by examining both Tim-3 expression and M/M??functions, and in particular, IL-12 production. 2) Determine the mechanisms by which Tim-3 is up-regulated on M/M??using an HCV-expressing hepatocyte model system, focusing on specific HCV antigen-mediated regulation of Tim-3 transcription, translation, biosynthesis and degradation. 3) Determine the effects of Tim-3 signaling in M/M??on host antiviral responses, including dendritic cell (DC) IL-12 expression, virus-specific CD4+ and CD8+ T lymphocyte responses, hepatocyte interferon (IFN) signaling and HCV replication. The overall goal of this proposal is to employ a translational approach to obtain a unified overview of how HCV-mediated Tim-3 up-regulation on M/M? alters IL-12 expression and host innate to adaptive immune responses to HCV infection, so as to develop effective strategies to combat this common viral disease. PUBLIC HEALTH RELEVANCE: HCV is characterized by persistent infection and poor treatment response. Why this virus is able to persist in the majority of infected individuals, and more than half of the most prevalent genotype 1 HCV-infected patients fail the standard antiviral treatment, remains unclear; but disruption of both innate and adaptive immune responses appears to play a major role. Based on our preliminary data, we suspect that a novel immunomodulator, Tim-3, is regulating the ability of innate immune cells, such as M/M?, to produce critical regulatory cytokines, such as IL-12, leading to disruption of subsequent T lymphocyte responses to HCV infection. This project will examine whether and how Tim-3 expression is regulated on M/M??in individuals with chronic HCV infection following antiviral therapy, with a focus on the virus and host interactions in a new system mimicking the HCV-infected liver as a model and manipulating Tim-3 signaling in M/M??as a tool. This study will facilitate effective approaches to improve viral clearance, and thus is significant and timely.

描述（申请人提供）：丙型肝炎病毒（HCV）在破坏人体免疫力以形成慢性感染方面表现出色；这是一个全球性的健康问题，治疗选择有限，而且没有可用的疫苗。目前尚不清楚病毒通过克服宿主固有的适应性免疫而在大多数受感染的肝脏中持续存在的机制。 部分原因是我们对导致这种免疫破坏的丙型肝炎病毒-宿主相互作用的了解不完全。我们之前已经证明，慢性 HCV 感染通过负性免疫调节剂的上调介导免疫失调，包括程序性死亡 1 (PD-1)、细胞因子信号传导抑制物 1 (SOCS-1) 以及最近的 T 细胞免疫球蛋白和粘蛋白结构域蛋白 3 (Tim-3)。虽然 Tim-3 已被证明在慢性病毒感染期间 T 细胞耗竭中发挥着关键作用，但其在 HCV 持久性和抗病毒反应中对先天免疫细胞的表达和功能仍然未知。我们最近发现 Tim-3 在 Toll 样受体 (TLR) 介导的先天免疫反应的负调节中发挥着关键作用，在从慢性 HCV 感染个体中分离出的单核细胞/巨噬细胞 (M/M?) 上表达上调以及与表达HCV的肝细胞共培养的健康M/M??。重要的是，阻断 Tim-3 信号传导可以恢复 IL-12 的表达，IL-12 是一种将先天免疫反应与适应性免疫反应联系起来的关键促炎细胞因子。这一新的观察结果表明，慢性 HCV 感染宿主体内无法清除病毒可能是 Tim-3 介导的先天免疫受损的结果，随后导致适应性免疫反应功能障碍。因此，我们假设 HCV 介导的 M/M?? 上的 Tim-3 上调在先天免疫和 IL-12 失调中发挥核心作用，因此阻断 M/M?? 中的 Tim-3 信号传导可能会挽救受损的抗病毒药物免疫反应。为了检验这一假设，我们将实现以下具体目标：1）定义Tim-3上调对M/M的作用？通过检查 Tim-3 表达和 M/M?? 功能，特别是 IL-12 的产生，与那些自然消退的 HCV 感染或健康受试者进行比较，进行抗病毒治疗后获得明确结果的 HCV 感染患者。 2) 使用表达HCV的肝细胞模型系统确定Tim-3在M/M上上调的机制，重点关注特定HCV抗原介导的Tim-3转录、翻译、生物合成和降解的调节。 3) 确定M/M??中Tim-3信号传导对宿主抗病毒反应的影响，包括树突状细胞(DC) IL-12表达、病毒特异性CD4+和CD8+ T淋巴细胞反应、肝细胞干扰素(IFN)信号传导和HCV复制。该提案的总体目标是采用转化方法来获得 HCV 介导的 Tim-3 如何上调 M/M 的统一概述？改变 IL-12 表达和宿主对 HCV 感染的先天适应性免疫反应，从而制定有效的策略来对抗这种常见的病毒性疾病。 公共卫生相关性：HCV 的特点是持续感染和治疗反应不佳。为什么这种病毒能够在大多数感染者体内持续存在，并且一半以上最流行的基因 1 型 HCV 感染患者未能接受标准抗病毒治疗，目前尚不清楚；但先天性和适应性免疫反应的破坏似乎起着重要作用。根据我们的初步数据，我们怀疑一种新型免疫调节剂 Tim-3 正在调节先天免疫细胞（例如 M/M？）产生关键调节细胞因子（例如 IL-12）的能力，从而导致后续细胞因子的破坏。 T 淋巴细胞对 HCV 感染的反应。该项目将研究抗病毒治疗后慢性 HCV 感染个体中 Tim-3 的表达是否以及如何在 M/M 上受到调节，重点是在模拟 HCV 感染肝脏的新系统中病毒和宿主的相互作用。模型并以 M/M?? 作为工具操纵 Tim-3 信号。这项研究将促进提高病毒清除的有效方法，因此具有重要意义和及时性。