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

RBV Pig项目总结/摘要 戊型肝炎病毒（HEV）是一种新兴的人畜共患病病原体，在发展中国家和发达国家都有流行。 包括美国在内的国家（美国）。HEV每年感染2000万人，导致330万人死亡。 有症状的病例，44，000人死亡。在像美国这样的国家，戊型肝炎的流行被认为是 对免疫功能低下的个体的危险，其中病毒变成慢性并可导致急性肝衰竭 以及其他后果。大约58-92%的HEV感染的器官移植受者 慢性戊型肝炎目前推荐的治疗慢性戊型肝炎病毒是利巴韦林（RBV）。已经 已经有RBV未能清除HEV感染的临床病例，导致患者预后不良。RBV 治疗失败归因于单核苷酸变异（SNV）HEV毒株， 准种在宿主中表现出对RBV的抗性和/或增强的复制。此外，长- 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（RPS 17）或S19（RPS 19）序列的插入，也导致 增强病毒复制和增加宿主范围。如何自然发生的HEV变异与增强 复制，如携带RPS 17或单核苷酸变体的复制，有助于病毒的发病机制， 目前未知。该项目的近期目标是适应现有的免疫抑制猪慢性 HEV系统，以模拟RBV治疗失败和由于变异HEV毒株导致的疾病严重程度。在特定 目的1，我们假设免疫抑制的猪模型与次优RBV治疗相结合， 将在临床环境中模拟患者治疗，导致新的HEV变体和增强的疾病 发病机制为了验证这一假设，我们将用野生型HEV实验性感染免疫抑制的猪 或变异型HEV，用RBV治疗一些群体。然后我们可以对产生的HEV变体进行测序， 变异型和野生型HEV组之间的疾病严重程度。在具体目标2中，我们假设SNV 在体外表现出增强的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 感染了野生型HEV和变异型HEV病毒，这些病毒来自特定目标1期间收集的样品。很长的- 本项目的长期目标是确定决定HEV感染结果的病毒和宿主相互作用 并开发策略和治疗方法，以减轻不良后果。R21的结果将是 重要的是未来深入的机制研究宿主因素在戊型肝炎病毒感染，特别是慢性和交叉感染， 种感染。我们的具体目标和长期目标与NIH的使命目标保持一致， 通过了解病毒因素，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.