Gene Expression Analyses During IFN Antiviral Therapy

描述（由申请人提供）：在世界范围内，约2%的人口感染HCV，其中50-80%发展为持续感染。目前，用于治疗慢性HCV感染的唯一批准的疗法是24-48周疗程的聚乙二醇化IFN α 2a或α 2b和利巴韦林的组合，对治疗的应答为42%（基因型1）和82%（基因型2/3）持续病毒清除。即使在没有持续应答的患者中，IFN（α）治疗通常也会导致HCV病毒载量快速下降;因此，尽管其他抗病毒药物正在开发，但IFN可能会继续用于联合治疗或作为初始预治疗以降低病毒载量。在HCV抗病毒治疗期间IFN的作用机制（或对IFN的耐药性）尚不清楚;然而，了解这些机制对于解释未来的HCV抗病毒治疗至关重要，无论是在IFN治疗的背景下，还是在第二代和第三代抗病毒药物靶向途径的特定方面。黑猩猩是目前HCV研究的唯一动物模型。将在HCV慢性感染黑猩猩中进行临床前试验评价。在这些动物中降低病毒载量的能力对于这些类型的研究的许多方面都是至关重要的。由于动物对人IFN无应答，因此本提案中概述的研究旨在克隆和表达黑猩猩IFN α 2基因，以在4只黑猩猩中提供种属特异性治疗（两只幼稚动物用于分析IFN应答的幅度;两只持续感染HCV的动物用于证明病毒载量减少和IFN应答的潜在调节）。随后，将对dsRNA（polyI：C）的应答与在未处理动物中用IFN观察到的应答进行比较，以研究在病毒感染期间发生的与IFN途径不同（但在许多情况下重叠）的初始分子事件（如由dsRNA模拟的）。使用来自肝活检和PBMC的RNA的基因表达研究将在每个处理方案中使用高密度DNA微阵列进行。这些分析的预期结果是鉴定与干扰素治疗后HCV持续性相关的宿主基因表达的变化，并与在未处理动物中观察到的变化进行比较。这些数据将有助于确定为什么干扰素治疗慢性HCV感染通常不成功，并为未来的治疗提供细胞靶点。

DESCRIPTION (provided by applicant): Worldwide, approximately 2% of the population is infected with HCV and 50-80% of those develop into persistent infections. Currently, the only approved therapy for treatment of chronic HCV infection is a 24-48 week course of the combination of pegylated IFNalpha2a or alpha2b and ribavirin with a response to treatment of 42% (genotype 1) and 82% (genotype 2/3) sustained viral clearance. Even in persons without sustained responses, IFN (alpha) therapy usually results in a rapid decline in HCV viral load; therefore, IFN will likely continue to be used in treatment either in combination therapies or as an initial pre-treatment to reduce viral load, despite the development of other antivirals. The mechanisms of actions of IFN (or resistance to IFN) during antiviral therapy for HCV are not understood; yet, understanding these mechanisms is critical for interpretation of future antiviral treatments for HCV, either in the context of IFN therapy, or with second and third generation antivirals targeting specific aspects of the pathway. Chimpanzees are the only animal model for HCV studies at this time. Pre-clinical trial evaluations will be performed in HCV chronically infected chimps. An ability to reduce viral load in these animals is crucial to many aspects of these types of studies. As the animals do not respond to human IFN, the studies outlined in this proposal aim to clone and express the chimp IFNalpha2 gene to provide species-specific therapy in four chimpanzees (two naive animals to analyze the magnitude of the IFN response; and two animals persistently infected with HCV to demonstrate a reduction in viral load and potential modulation of the IFN response). Subsequently, the response to dsRNA, (polyl:C) will be compared to that observed with IFN in the naive animals to investigate the initial molecular events occurring during virus infection (as mimicked by dsRNA) that are distinct (but overlapping in many cases) from the IFN pathway. Gene expression studies using RNA from liver biopsies and PBMCs will be performed with high density DNA microarrays with each treatment regime. The expected outcomes of these analyses are the identification of changes in host gene expression associated with HCV persistence following interferon therapy in comparison to the changes observed in naive animals. These data will help determine why interferon therapy is often unsuccessful for chronic HCV infections and provide cellular targets for future therapies.