Towards a Novel Strategy Against HBV Infection

描述（由申请方提供）：长期目标是开发一种新型HBV抗病毒策略，当与现有抗病毒药物联合使用时，将为治疗慢性感染患者提供更强大的治疗方法。现有的抗病毒药物靶向逆转录。第二种方法是使用干扰素治疗，但效果较差且副作用明显。其他方法已经提出了反义、核酶、细胞因子和最近的siRNA。然而，什么应该是一个高度可及的目标，病毒附着和进入，在很大程度上被忽视了，主要是由于缺乏对HBV如何实际附着和进入易感细胞的理解。考虑到这一缺陷，三个特定目标针对病毒组装，附着，进入和启动基因组复制的重要未解决的问题。这些研究将利用人丁型肝炎病毒（HDV）（人乙型肝炎病毒（HBV）的天然卫星）的组装依赖于HBV包膜蛋白（HBsAg）的事实。已经有数据支持HBV和HDV使用相同（或至少非常相似）的机制附着和进入易感细胞的合理假设。该策略是利用测定HDV基因组复制作为成功进入的指标的优势来检查这种机制。其目标如下：（i）建立HDV受控组装的条件，并在两种不同的肝细胞系统中评估实现附着、进入和复制起始的能力。(ii)使用未修饰和/或修饰形式的HBV包膜蛋白进行病毒体组装，并鉴定附着、进入和启动HDV复制所需的决定簇。(iii)测试小分子对附着和进入的干扰，并朝着开发高通量筛选测定的方向发展。总体而言，特定目的1和2中提出的研究提供了与HBV（和HDV）如何能够附着并随后进入易感细胞并启动复制相关的新的重要信息。这一信息反过来又可能导致在特定目标3中开发一个或多个步骤的感染抑制剂。然后，与Stressgen Biotechnologies合作，开发的检测方法将用于筛选多种化合物以提高疗效，并最终进入临床研究。

DESCRIPTION (provided by applicant): The long-term goal is to develop a novel HBV antiviral strategy, that when used in combination with existing antiviral agents, will provide a more powerful therapy for treating chronically infected patients. Existing antivirals target reverse transcription. A second approach, but less effective and with significant side-effects, utilizes interferon therapy. Other approaches have suggested antisense, ribozymes, cytokines, and more recently siRNA. However, what should be a highly accessible target, virus attachment and entry, has been largely ignored, primarily due to lack of understanding as to how HBV actually attaches to and enters susceptible cells. With this deficit in mind, three Specific Aims are directed at important unsolved issues of virus assembly, attachment, entry, and the initiation of genome replication. These studies will exploit the fact that the assembly of human hepatitis delta virus (HDV), a natural satellite of human hepatitis B virus (HBV), is dependent upon HBV envelope proteins (HBsAg). There are already data to support the reasonable assumption that HBV and HDV use the same (or at least a very similar) mechanism for attachment and entry into susceptible cells. The strategy is to examine this mechanism exploiting the advantages of assaying HDV genome replication as the indicator for successful entry. The aims are as follows: (i) Establish conditions for the controlled assembly of HDV and evaluate in two different hepatocyte systems the ability to achieve attachment, entry, and the initiation of replication. (ii) Use unmodified and/or modified forms of HBV envelope proteins for virion assembly, and identify of determinants necessary for attachment, entry, and initiation of HDV replication. (iii) Test small molecules for interference with attachment and entry, and move towards the development of high throughput screening assays. Overall, the studies proposed in Specific Aims 1 and 2 provide new and important information relevant to how HBV (and HDV) are able to attach to and then enter and initiate replication in susceptible cells. This information in turn could lead in Specific Aim 3 to the development of inhibitors of infection at one or more steps. Then, in collaboration with Stressgen Biotechnologies, the developed assays will be used to screen multiple compounds to increase efficacy, and ultimately move to clinical studies.