Conformational change in HSV glycoprotein B

描述（由申请人提供）：单纯疱疹病毒（HSV）在人类中引起终身潜伏感染。它是造成重大疾病的原因，从唇疱疹和生殖器感染到新生儿感染、失明和致命脑炎。该项目的长期目标是了解HSV进入宿主细胞的分子机制。疱疹病毒膜融合和进入是一个复杂的级联反应，涉及多种病毒糖蛋白和多种细胞触发器。疱疹病毒学中一个新兴的概念是，宿主细胞的内体pH值是病毒进入所必需的，通常以细胞类型特异性的方式进入。低pH的作用机制尚不清楚。我们最近发现HSV包膜糖蛋白B （gB）是内体pH的主要靶标。在体外和病毒进入细胞期间，轻度酸性的pH可逆地改变gB的抗原结构和寡聚构象。基于这些新发现的构象变化，我们建议开发疱疹病毒进入抑制剂，并阐明gB在驱动融合反应中的作用。在Specific Aim # 1中，我们将验证gB构象改变是抗病毒干预的新靶点的假设。我们将确定特异性和有效的肽抑制剂的gB结构转变。将评估抑制剂阻断病毒膜融合和进入的能力。具体目标2，我们将定义gB细胞质尾部对其构象改变和膜融合的贡献。我们的实验设计采用细胞生物学、生物化学和分子病毒学技术。HSV在上皮细胞中利用ph依赖的内吞途径，上皮细胞是人类宿主的初始入口。因此，实现这些目标将描述靶细胞初始感染机制的关键步骤，并揭示预防它的方法。结果将为gB的构象变化及其与膜融合的关系提供一个机制的理解。

DESCRIPTION (provided by applicant): Herpes simplex virus (HSV) causes lifelong latent infections in humans. It is responsible for significant disease, ranging from cold sores and genital infections to neonatal infections, blindness and fatal encephalitis. The long-term goal of this project is to understand the molecular mechanisms that HSV uses to gain entry into host cells. Herpesvirus membrane fusion and entry is a complex cascade of interactions involving multiple viral glycoproteins and multiple cellular triggers. An emerging concept in herpesvirology is that the endosomal pH of the host cell is required for viral entry, often in a cell type specifi manner. The mechanistic role that low pH plays is not clear. We recently identified HSV envelope glycoprotein B (gB) as the principal target of endosomal pH. Mildly acidic pH reversibly alters the antigenic structure and oligomeric conformation of gB in vitro and during virus entry into cells. Based on these newly identified conformational changes, we propose to develop herpesviral entry inhibitors and to elucidate the role of gB in driving the fusion reaction In Specific Aim # 1, we will test the hypothesis that gB conformation change is a novel target for antiviral intervention. We will identify specific and potent peptide inhibitors of gB structural transition. Inhibitors will be assessed for the ability to block viral membrane fusion and entry. I Specific Aim # 2, we will define the contribution of the gB cytoplasmic tail to its conformation change and membrane fusion. Our experimental design employs techniques of cell biology, biochemistry, and molecular virology. HSV utilizes a pH-dependent endocytosis pathway in epithelial cells, the initial portal of entry in the human host. Thus, achieving these aims will delineate a key step in the mechanism of the initial infection of target cells and reveal a means to prevent it. The results will provide a mechanistic understanding of conformational change in gB and its relation to membrane fusion. PUBLIC HEALTH RELEVANCE: Herpes simplex virus infections are common in humans and can cause serious complications such as neonatal disease, blindness and fatal encephalitis. This research concerns how the herpesvirus initiates infection in humans by studying the entry of virus into host cells at the molecular level. Greater understanding of how this process works will help to develop novel anti-viral approaches for preventing herpes infections.