Towards a Novel Strategy Against HBV Infection

描述(申请人提供)：长期目标是开发一种新的乙肝病毒抗病毒策略，当与现有的抗病毒药物结合使用时，将为治疗慢性感染患者提供更有效的治疗方法。现有的抗病毒药物针对的是逆转录。第二种方法是使用干扰素治疗，但效果较差，副作用很大。其他方法包括反义、核酶、细胞因子，以及最近的siRNA。然而，病毒附着和进入这一本应高度可及的目标在很大程度上被忽视了，这主要是因为对乙肝病毒实际是如何附着和进入敏感细胞缺乏了解。考虑到这一缺陷，有三个具体目标针对尚未解决的重要问题，即病毒组装、附着、进入和启动基因组复制。这些研究将利用这样一个事实，即人类丁型肝炎病毒(HDV)的组装依赖于HBV膜蛋白(HBs Ag)，HDV是人类乙肝病毒(HBV)的天然卫星。已经有数据支持合理的假设，即乙肝病毒和丁型肝炎病毒使用相同(或至少非常相似)的机制附着和进入敏感细胞。该策略是利用检测HDV基因组复制作为成功进入的指示器的优势来研究这一机制。目的如下：(I)为HDV的受控组装创造条件，并在两种不同的肝细胞系统中评估实现附着、进入和启动复制的能力。(2)使用未修饰和/或修饰形式的乙肝病毒包膜蛋白进行病毒粒子组装，并确定附着、进入和启动HDV复制所需的决定因素。(3)测试小分子对附着和进入的干扰，并朝着高通量筛选分析的方向发展。总体而言，在特定目标1和2中提出的研究提供了与乙肝病毒(和HDV)如何能够附着在易感细胞上，然后进入并在敏感细胞中启动复制相关的新的重要信息。这些信息反过来可能导致在一个或多个步骤中开发感染抑制剂的具体目标3。然后，与Stressgen BioTechnologies合作，开发的分析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.