Role of Cell Integrins in Adenoviral Conjunctivitis

腺病毒与急性呼吸道、胃肠道和眼部感染有关。虽然几种不同的Ad类型可引起眼部感染（病毒性红眼），但只有D亚型Ad类型（Ad37、Ad19和Ad8）与一种特别严重的眼部疾病（即流行性角膜结膜炎（EKC））相关。直到最近，对D亚群宿主细胞趋向性的认识还是相当有限的。我们发现相对较短且不灵活的Ad37纤维蛋白限制了病毒与CAR的相互作用，CAR是大多数其他Ad类型使用的细胞受体。为了克服这一限制，Ad37使用一种独特的细胞受体CD46（也称为膜辅因子蛋白）与宿主细胞结合。在这一建议中，我们将使用生化和分子遗传学方法研究Ad37与CD46结合的精确分子相互作用。补充研究将使用低温电子显微镜或x射线衍射在中至高分辨率下分析Ad-CD46配合物的三维结构。CD46已经被多种微生物病原体篡夺，因此，这种受体可能具有宿主细胞识别之外的重要功能。在这方面，我们最近的研究表明，Ad37下调白细胞介素-12 （IL-12）的表达。这种关键的炎症细胞因子连接先天和适应性免疫反应，因此可能在病毒清除中起关键作用。在进一步的研究中，我们将研究ad介导的细胞因子调节的机制。我们还将分析CD46在相关细胞和动物模型中的表达是否在体外和体内增强Ad37感染。这些研究增加了我们对Ad向性和眼部发病机制的认识。它们还可能为开发新的抗病毒药物以及改进的基因传递载体提供见解。

Adenoviruses are associated with acute respiratory, gastrointestinal, and ocular infections. While several different Ad types can cause eye infections (viral pink eye), only subgroup D Ad types (Ad37, Ad19 and Ad8) are associated with a particularly severe ocular disease known as epidemic keratoconjunctivitis (EKC). Until recently, knowledge of subgroup D host cell tropism was quite limited. We discovered that the relatively short and inflexible Ad37 fiber protein restricts virus interactions with CAR, the cell receptor used by most other Ad types. To overcome this limitation, Ad37 uses a distinct cell receptor, CD46 (also known as Membrane Cofactor Protein) to bind to host cells. In this proposal, we will investigate the precise molecular interactions involved in Ad37 binding to CD46 using biochemical and molecular genetic approaches. Complementary studies will analyze the three dimensional structure of Ad-CD46 complexes at moderate to high resolution using cryoelectron microscopy or X-ray diffraction. CD46 has been usurped by diverse microbial pathogens and thus, this receptor may serve important functions beyond host cell recognition. In this regard, our recent studies showed that Ad37 downregulates expression of interleukin-12 (IL-12). This key inflammatory cytokine links the innate and adaptive immune response and therefore may play a crucial role in viral clearance. In further studies, we will examine the mechanisms involved in Ad-mediated cytokine regulation. We will also analyze whether CD46 expression in relevant cell and animal models enhances Ad37 infection in vitro and in vivo. These studies should increase our understanding of Ad tropism and ocular pathogenesis. They may also provide insights for the development of novel antiviral agents as well as improved gene delivery vectors.