Cell surface events of human papillomavirus type 16 and 18 infection

描述（由申请人提供）：人乳头瘤病毒（HPV）是一个大家族的病毒，其中一些与各种形式的癌症有关，包括宫颈癌。它们诱发的癌症占全世界女性癌症总数的7%以上。特别是，由于缺乏癌症筛查项目，HPV对世界上欠发达地区的妇女构成了负担。这项研究的长期目标是了解HPV感染的早期事件，重点关注发生在细胞表面的事件。HPV 16型的主要衣壳蛋白L1主要负责病毒与存在于细胞表面和细胞外基质（ECM）上的硫酸肝素蛋白聚糖（HSPG）的初始结合。附着在HSPG上诱导L1和次要衣壳蛋白L2的构象发生变化，我们现在可以用单克隆抗体检测这两种构象。与X. Chen合作的x射线结构分析鉴定了病毒衣壳上的几个HSPG结合位点。我们的初步数据表明，它们在初级附着和次级结合事件以及诱导构象转移中依次使用。此外，我们收集的证据表明，在HPV感染过程中，亲环蛋白B （CyPB）参与了两个不同的步骤：介导细胞表面L2构象变化和促进病毒基因组的脱壳。目的1将验证我们的假设，即在HPV感染的细胞表面事件中，病毒衣壳上的两个HS结合位点依次使用。这将通过结构导向的HS结合位点诱变来实现。目的2是利用siRNA敲除和小分子抑制剂结合生化和细胞生物学方法来描述亲环蛋白在HPV感染中的功能。Aim 3致力于了解影响两种衣壳蛋白分子细节的构象变化的潜在过程。详细了解这些事件将有助于开发对抗hpv诱导的恶性病变的干扰策略。公共卫生相关性：HPV诱发多种癌症，包括宫颈癌。我们将研究病毒如何利用宿主细胞因子附着在宿主细胞上以及随后导致成功感染的事件。这将有助于确定药物治疗的细胞靶标，以预防HPV诱导的癌症。

DESCRIPTION (provided by applicant): Human papillomaviruses (HPV) form a large family of viruses some of which are associated with various forms of cancer, including cervical carcinoma. They induce more than seven per cent of all cancers in women worldwide. Especially, HPV pose a burden to women in underdeveloped regions in the world due to a lack of access to cancer screening programs. The long term goal of this research is to understand early events of HPV infection with the focus on events occurring on the cell surface. The major capsid protein, L1, of HPV type 16 is primarily responsible for initial binding of virus to heparan sulfate proteoglycan (HSPG) present on cell surface and extracellular matrix (ECM). Attachment to HSPG induces a shift in the conformation of L1 and the minor capsid protein, L2, both of which we can now detect with monoclonal antibodies. X-ray structure analysis in collaboration with X. Chen identified several HSPG binding sites on the viral capsid. Our preliminary data suggest their sequential use in primary attachment and secondary binding events as well for inducing conformational shifts. In addition, we collected evidence for an involvement of Cyclophilin B (CyPB) in two distinct steps during HPV infection: mediating L2 conformational changes on the cell surface and facilitating uncoating of the viral genome. Aim 1 will test our hypothesis that two HS binding sites on the viral capsid are sequentially used during cell surface events of HPV infection. This will be achieved by a structure-guided mutagenesis of HS binding sites. Aim 2 is intended to delineate the function of Cyclophilins in HPV infection using siRNA knock down and small molecule inhibitors combined with biochemical and cell biological approaches. Aim 3 is dedicated to understand the processes underlying the conformational shifts affecting both capsid proteins in molecular detail. Understanding these events in detail will allow the development of interfering strategies to fight HPV-induced malignant lesions. PUBLIC HEALTH RELEVANCE: HPV induce a variety of cancers, including cervical carcinoma. We will investigate how the virus exploits host cell factors for attachment to host cells and subsequent events leading to successful infection. This should allow identification of cellular targets for drug therapies to prevent HPV induced cancers.