Evaluating hepatitis E virus ribavirin resistance clinical outcomes in the immunosuppressed pig model

RBV猪项目摘要/摘要 戊型肝炎病毒(HEV)是一种新出现的人畜共患病原体，在发展中国家和发达国家都有流行 包括美国(美国)在内的国家。HEV每年感染2000万人，导致330万人感染 有症状的病例有44,000人死亡。在美国等国家，HEV的流行被认为是一种 病毒变得慢性并可导致急性肝功能衰竭对免疫功能低下的人构成危险 在其他后果中。大约58-92%感染HEV的器官移植受者 慢性戊型肝炎病毒感染。目前推荐的慢性HEV治疗方法是利巴韦林(RBV)。有 已经有临床病例表明，RBV未能清除HEV感染，导致患者预后不佳。RBV 治疗失败归因于单核苷酸变异(SNV)HEV毒株，这种毒株可以作为 寄主中对RBV表现出抗性和/或增强复制的准种。此外，长久以来- HEV在慢性感染宿主中的长期复制导致了病毒准种的鉴定 含有宿主核糖体蛋白S17(RPS17)或S19(RPS19)序列的插入也导致 增强了病毒复制并扩大了宿主范围。自然产生的HEV变种如何增强 复制，例如那些携带RPS17或单核苷酸变体的复制，有助于病毒的致病 目前尚不清楚。这个项目的直接目标是使现有的免疫抑制的猪慢性 HEV系统模拟RBV治疗失败和因变异HEV毒株而导致的疾病严重程度。具体而言 目的1，我们假设免疫抑制的猪模型结合次优的RBV治疗 是否会在临床环境中模仿患者的治疗，从而产生新的HEV变种和增强的疾病 发病机制。为了验证这一假设，我们将用野生型HEV感染免疫抑制的猪 或变异戊型肝炎病毒，用RBV治疗某些组。然后我们可以对产生的HEV变种进行测序和比较 变异株和野生型HEV组之间的疾病严重程度。在特定目标2中，我们假设SNV 在体外表现出增强生长潜力的变体将与体内增强的疾病相关，部分原因是 不同的宿主免疫反应。为了验证这一假设，我们将描述猪的免疫反应。 从特定目标期间采集的样本中感染野生型HEV和变异HEV病毒1。 这个项目的学期目标是确定病毒和宿主的相互作用，这决定了HEV感染的结果 并制定能够缓解不良结果的战略和治疗方法。此R21的结果将是 这对于今后深入研究HEV感染的宿主因素，特别是慢性和交叉感染的宿主因素具有重要意义 物种感染。我们的具体目标和长期目标与NIH的任务目标非常一致，寻求 通过了解病毒致病因素，增进健康，延长寿命，减少疾病和残疾 肝功能衰竭和实体器官移植排斥反应。

RBV Pig Project Summary/Abstract Hepatitis E virus (HEV) is an emerging zoonotic pathogen endemic in both developing countries and in developed countries including the United States (U.S.). HEV infects 20 million individuals annually, resulting in 3.3 million symptomatic cases with 44,000 deaths. In countries like the U.S., HEV prevalence is being recognized as a danger to immunocompromised individuals where the virus becomes chronic and can result in acute liver failure among other consequences. Approximately 58-92% of HEV-infected organ transplant recipients developed chronic HEV infection. Currently the recommended treatment for chronic HEV is ribavirin (RBV). There have already been clinical cases where RBV has failed to clear HEV infection, resulting in poor patient outcome. RBV treatment failure has been attributed to single nucleotide variant (SNV) HEV strains that can be circulating as quasispecies in the host that have shown resistance to RBV and/or enhanced replication. Furthermore, long- term replication of HEV in the chronically infected host has led to the identification of viral quasispecies that contained insertions of host ribosomal protein S17 (RPS17) or S19 (RPS19) sequences also leading to enhanced viral replication and increased host range. How naturally occurring HEV variants with enhanced replication, such as those harboring RPS17 or single nucleotide variants, contribute to viral pathogenesis is currently unknown. The immediate goal of this project is to adapt the existing immunosuppressed pig chronic HEV system to model RBV treatment failure and resulting disease severity due to variant HEV strains. In specific aim 1, we hypothesize that the immunosuppressed swine model in conjunction with suboptimal RBV treatment will mimic patient treatment in the clinical setting resulting in novel HEV variants and enhanced disease pathogenesis. To test this hypothesis, we will experimentally infect immunosuppressed pigs with wild type HEV or variant HEV, treating some groups with RBV. We can then sequence resulting HEV variants and compare disease severity between variant and wild type HEV groups. In specific aim 2, we hypothesize that SNV variants exhibiting enhanced growth potential in vitro will correlate to enhanced disease in vivo in part due to differential host immune responses. To test this hypothesis, we will characterize the immune response in pigs infected with wild type HEV, and variant HEV viruses from samples collected during specific aim 1. The long- term goal of this project is to determine viral and host interactions that dictate the outcome of infection by HEV and develop strategies and therapeutics that can mitigate poor outcomes. The results from this R21 will be important for future in-depth mechanistic studies of host factors in HEV infection, especially chronic and cross- species infection. Our specific aims and long-term objectives align well with NIH mission goals seeking to enhance health, lengthen life, and reduce illness and disability through understanding viral factors contributing to liver failure and solid organ transplant rejection.