Ethanol suppresses HBV peptide-MHC Class I presentation on hepatocytes

乙醇抑制 HBV 肽-MHC I 类在肝细胞上的呈递

• 批准号: 10222487
• 负责人: Murali Ganesan
• 金额: $ 13.67万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10222487
• 关键词: Acetaldehyde; Affect; Alcohol abuse; Alcohol consumption; Alcoholic Liver Diseases; Alcohols; Antigen Presentation; Antigens; Cell membrane; Cell surface; Cells; Chronic; Chronic Hepatitis; Chronic Hepatitis B; Cirrhosis; Clinical; Clinical Research; Complex; Cytosol; Cytotoxic T-Lymphocytes; Data; Defect; Endoplasmic Reticulum; Ethanol; Ethanol Metabolism; Event; Fibrosis; General Population; Golgi Apparatus; HLA-A2 Antigen; HepG2; Hepatic; Hepatitis B; Hepatitis B Virus; Hepatocyte; High Prevalence; Human; Immune; Immune Targeting; Immune response; Immune system; Impairment; In Vitro; Incidence; Interferon Type II; Interferons; Lead; Liver; Major Histocompatibility Complex; Masks; Mediating; Modality; Mus; Outcome; Patients; Peptides; Primary carcinoma of the liver cells; Process; Role; Scheme; Severities; Site; Surface; TAP1 gene; TAP2 gene; Techniques; Testing; Viral; Viral Antigens; Virus; Virus Diseases; Virus Replication; Work; adaptive immune response; alcohol abuser; alcohol effect; antigen processing; antigenic peptide transporter; base; chronic liver disease; cytotoxic CD8 T cells; epidemiology study; innovation; insight; multicatalytic endopeptidase complex; novel; particle; peptide I; prevent; problem drinker; protein transport; reconstitution; tapasin; therapeutic development; therapy development; trafficking; virus core

ABSTRACT Hepatitis B virus (HBV) infection is one of the leading causes of hepatic decompensation and hepatocellular carcinoma worldwide; approximately 400 million people are infected with HBV. Due to the high prevalence of alcohol consumption in the general population, a significant portion of chronic HBV patients are also chronic alcohol abusers. Alcohol intake prolongs HBV persistence leading to establishment of chronic hepatitis. The mechanisms of rapid HBV infection progression and severe outcomes in alcohol-consuming patients are not clear. The virus is not cytopathogenic, and effective clearance requires the induction of an adaptive immune response, mainly via virus-specific CD8+ cytotoxic T lymphocytes (CTLs), which recognize viral peptide-major histocompatibility complex (MHC) class I on infected hepatocytes. While many studies have focused on alcohol-induced impairments of the immune response, information on how alcohol masks the presentation of HBV peptide-MHC class I complex on infected hepatocyte surfaces for escaping recognition by CTLs is missing. Therefore, the main focus of this study is to understand the effects of ethanol metabolism on the expression of the HBV peptide-MHC class I complex on HBV-infected hepatocytes. The presentation of this complex on cell membranes requires antigen processing by proteasomes in the cytosol, loading of peptides into MHC class I, assembly of peptide-loading complex with transporters for antigen presentation (TAP), its stabilization by tapasin in endoplasmic reticulum, and trafficking of this complex via trans-Golgi to the hepatocyte surface. Almost all of these steps are interferon-gamma dependent. Recently, we have found that the ethanol metabolite, acetaldehyde (Ach), suppresses HBV core peptide 18-27 presentation on HBV+ hepatocytes, which is accompanied by dysregulation of proteasome function, reduction in TAP1/tapasin expression and Golgi fragmentation, all of which work in combination to impair HBV-MHC class I complex presentation on infected hepatocytes. Based on these preliminary data, we put forth the hypothesis that ethanol metabolism decreases the display of HBV peptide-MHC class I complex on the hepatocyte surface by impairing viral peptide cleavage by the proteasome and by disrupting peptide-MHC class I trafficking to the cell surface. We will utilize a variety of state-of-the art and innovative techniques to test our novel hypothesis. The three specific aims of the proposed study are to: 1) Examine the effects of ethanol metabolism and HBV on antigenic peptide processing for MHC class I-restricted antigen presentation on hepatocytes; 2) Determine how ethanol metabolism affects the trafficking of peptide loading complex for expressing HBV peptide-MHC class I on hepatocytes; 3) Validate the results of specific aims 1-2 using chimeric mice double-reconstituted with human hepatocytes and a human immune system. Completion of the proposed studies will help in the development of treatment modalities for preventing the persistence of hepatitis B in alcohol abusing patients.

抽象的 乙型肝炎病毒（HBV）感染是导致肝功能失代偿和肝细胞损伤的主要原因之一。 全世界的癌症；大约有 4 亿人感染 HBV。由于患病率高 在一般人群中饮酒，很大一部分慢性乙型肝炎患者也是慢性乙型肝炎患者 酗酒者。酒精摄入会延长乙肝病毒的持续时间，导致慢性肝炎的形成。这 饮酒患者中乙型肝炎病毒感染快速进展和严重后果的机制尚不明确 清除。该病毒不具有致细胞病变性，有效清除需要诱导适应性免疫 反应，主要通过病毒特异性 CD8+ 细胞毒性 T 淋巴细胞 (CTL)，其识别病毒主要肽 受感染肝细胞上的 I 类组织相容性复合物 (MHC)。虽然许多研究都集中在 酒精引起的免疫反应损伤，有关酒精如何掩盖免疫反应的信息 受感染肝细胞表面的 HBV 肽-MHC I 类复合物，用于逃避 CTL 的识别 丢失的。因此，本研究的主要重点是了解乙醇代谢对 HBV 肽-MHC I 类复合物在 HBV 感染的肝细胞上的表达。本次的介绍 细胞膜上的复合物需要细胞质中的蛋白酶体对抗原进行加工，装载肽 进入 MHC I 类，肽负载复合物与抗原呈递转运蛋白 (TAP) 的组装，其 内质网中塔帕辛的稳定作用，以及该复合物通过反高尔基体运输到 肝细胞表面。几乎所有这些步骤都依赖于干扰素γ。最近，我们发现 乙醇代谢物乙醛 (Ach) 可抑制 HBV+ 上的 HBV 核心肽 18-27 呈递 肝细胞，伴有蛋白酶体功能失调、TAP1/tapasin 减少 表达和高尔基体断裂，所有这些共同作用损害 HBV-MHC I 类复合物 受感染肝细胞的表现。根据这些初步数据，我们提出假设 乙醇代谢降低了肝细胞上 HBV 肽-MHC I 类复合物的展示 通过损害蛋白酶体对病毒肽的切割以及破坏肽-MHC I 类来破坏表面 运输到细胞表面。 我们将利用各种最先进的创新技术来检验我们的新颖假设。三个 本研究的具体目的是： 1) 检查乙醇代谢和 HBV 对抗原的影响 肝细胞上 MHC I 类限制性抗原呈递的肽加工； 2) 确定乙醇的含量 代谢影响表达 HBV 肽-MHC I 类的肽负载复合物的运输 肝细胞； 3) 使用与人类双重组的嵌合小鼠验证特定目标1-2的结果 肝细胞和人体免疫系统。完成拟议的研究将有助于发展 预防酗酒患者持续存在乙型肝炎的治疗方式。