Gene Expression Analyses During IFN Antiviral Therapy

描述(申请人提供)：在世界范围内，大约2%的人口感染丙型肝炎病毒，其中50%-80%发展为持续性感染。目前，唯一被批准的治疗慢性丙型肝炎病毒感染的方法是24-48周的聚乙二醇化IFNalpha2a或Alpha2b与利巴韦林的联合治疗，治疗有效率为42%(基因1)和82%(基因2/3)持续病毒清除。即使在没有持续应答的人中，干扰素(α)治疗通常会导致丙型肝炎病毒载量迅速下降；因此，尽管有其他抗病毒药物的开发，干扰素仍可能继续用于联合治疗或作为减少病毒载量的初始预治疗。在丙型肝炎病毒的抗病毒治疗中，干扰素(或对干扰素的抵抗)的作用机制尚不清楚；然而，了解这些机制对于解释未来的丙型肝炎抗病毒治疗至关重要，无论是在干扰素治疗的背景下，还是在第二代和第三代抗病毒药物靶向该途径的特定方面。黑猩猩是目前丙型肝炎病毒研究的唯一动物模型。将在慢性感染丙型肝炎病毒的黑猩猩身上进行临床前试验评估。降低这些动物体内病毒载量的能力对这些类型研究的许多方面都是至关重要的。由于动物对人类干扰素没有反应，这项建议中概述的研究旨在克隆和表达黑猩猩IFNalpha2基因，以便为四只黑猩猩提供物种特异性治疗(两只幼稚的动物分析干扰素反应的幅度；以及两只持续感染丙型肝炎病毒的动物，以证明病毒载量的减少和干扰素反应的潜在调节)。随后，将比较幼年动物对dsRNA的反应和用干扰素观察到的反应，以调查病毒感染期间发生的初始分子事件(如dsRNA模仿的那样)，这些事件与干扰素途径截然不同(但在许多情况下是重叠的)。使用来自肝脏活检和PBMC的RNA进行的基因表达研究将在每种治疗方案下使用高密度DNA微阵列进行。这些分析的预期结果是确定与干扰素治疗后丙型肝炎病毒持续相关的宿主基因表达的变化，并与在幼稚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丙型肝炎病毒感染往往不成功，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.