Glycosaminoglycan-papillomavirus interactions: From structure to function and inhibition

人乳头瘤病毒（HPV）是一个大家族的无包膜DNA肿瘤病毒。其中，HPV 16是包括宫颈癌在内的各种肛门生殖器肿瘤的主要原因。为了进入宿主细胞，HPV 16最初与硫酸乙酰肝素蛋白聚糖（HSPG）结合。最近，我们的研究表明，HPV 16衣壳与HSPG的糖胺聚糖（GAG）链的初始相互作用足以诱导构象变化。这有助于病毒颗粒中的进一步结构改变，导致受体转换和制备颗粒用于脱壳，即病毒基因组从衣壳结构释放（Cerqueira等人，2013; Cerqueira等人，2015）。病毒的这种结构活化似乎严重依赖于高硫酸化含量、硫酸化模式、某种碳水化合物主链和GAG链的长度。这一观察结果提出了一个有趣的可能性，即不同HPV类型的粘膜与皮肤上皮细胞的嗜性取决于GAGs.In这个项目中，我们的目标是阐明结构的先决条件和后果的GAG-HPV相互作用的组织依赖性硫酸化patterning。为此，我们将使用已建立的基于细胞的检测方法，结合研究组内的结构生物学方法，以确定GAG和HPV衣壳的结合、结构活化和抑制潜力的结构限制。一方面，我们将探索各种进化多样的HPV类型和HS聚糖，以阐明这种相互作用的共同主题和具体差异。另一方面，我们将定义引起HPV 16结构活化的理想GAG结构，以及构象变化的分子细节。本研究中使用的方法库利用了Forschergruppe的跨学科方法，包括但不限于基于细胞的测定、质谱、核磁共振研究和精密糖模拟物聚合物的使用。总的来说，我们希望确定HS-HPV衣壳相互作用的结构和功能后果，这将使我们能够提出一个全面的HS依赖性进入模型，这反过来又可用于开发预防性抗HPV化合物。

Human papillomaviruses (HPV) are a large family of non-enveloped DNA tumor viruses. Of those, HPV16 is the leading cause for a variety of anogenital tumors including cervical cancer. For entry into host cells, HPV16 initially binds to heparan sulfate proteoglycans (HSPGs). Recently, our research demonstrated that the initial interaction of HPV16 capsids with the glycosaminoglycan (GAG) chains of HSPGs is sufficient to induce a conformational change. This facilitates further structural alterations in the virus particle resulting in receptor switching and preparing the particle for uncoating, i.e. the release of the viral genome from the capsid structure (Cerqueira et al., 2013; Cerqueira et al., 2015). This structural activation of the virus appears to be critically dependent on a high sulfation content, on the sulfation pattern, on a certain carbohydrate backbone, and on the lengths of the GAG chain. This observation raises the interesting possibility that the tropism of different HPV types for mucosal vs. skin epithelia depends on a tissue-dependent sulfation patterning of GAGs.In this project, we aim to elucidate the structural prerequisites and consequences of GAG-HPV interactions. For this, we will use an established repertoire of cell-based assays in combination with structural biology approaches within the Forschergruppe to define the structural constraints of the GAG and HPV capsids for binding, structural activation, and inhibitory potential. On the one hand, we will probe the variety of evolutionary diverse HPV types and HS glycans to elucidate common themes and specific differences for this interaction. On the other hand, we will define the ideal GAG structure to cause structural activation of HPV16, as well as the molecular details of the conformational change. The repertoire of methods used in this study capitalizes on the interdisciplinary approach of the Forschergruppe and includes but is not limited to cell-based assays, mass spectrometry, nuclear magnetic resonance studies, and the use of precision glycomimetic polymers. Overall, we expect to identify structural and functional consequences of HS-HPV capsid interactions that will allow us to propose a comprehensive model of HS-dependent entry, which, in turn, could be used to develop preventative anti-HPV compounds.