Chlamydial invasion of non-phagocytic cells

项目摘要 沙眼衣原体是中国最普遍的性传播感染（STI）的病原体， 在发达国家，沙眼是致盲性疾病。有一个 据估计，全世界每年有9300万例新报告的衣原体性传播感染病例。沙眼影响 大约1.5亿人，主要是妇女和儿童。两者的病理特征 疾病是由慢性炎症引起的疤痕;而炎症在疾病的早期阶段 感染由上皮细胞的感染开始，并通过活跃的细菌复制持续， 沿着生殖器和眼粘膜传播。 衣原体是一种革兰氏阴性专性细胞内病原体，这意味着它需要细胞内的 它的生存和复制环境。因此，允许宿主细胞的入侵对其免疫应答至关重要。 生存和发病机制。在体内，主要靶点是眼和生殖器上皮细胞。 粘膜。我们的总体假设是，入侵是一个衣原体驱动的过程。这种病原体 进化的机制操纵宿主细胞肌动蛋白细胞骨架的诱导其吸收，导致 形成旨在吞噬细菌的细胞表面结构。入侵涉及到一系列的信号 在正常细胞中起调节肌动蛋白细胞骨架动力学作用的途径。细菌会开启 机械在其网站的粘附，与位置的肌动蛋白重塑决定的限制， 称为TarP的衣原体毒力蛋白易位到宿主细胞浆的胞质侧 膜的TarP招募了许多信号分子来启动肌动蛋白细胞骨架的重塑， 然后被病原体吞噬 一旦进入细胞，病原体就有机会劫持其他细胞过程，包括 引发炎症，持续时导致组织损伤和眼结膜瘢痕形成 导致不育的生殖道。因此，衣原体致病的能力始于入侵。 虽然我们对TarP在入侵过程中的功能有了更好的了解，但关于它是如何运作的机制细节， 规范是稀疏的。本申请将研究机械转导在调节TarP中的作用。 与宿主信号分子的相互作用。将讨论以下具体目标。（一）确定 TarP机械感应在侵袭中的机制和意义; II）确定肌球蛋白II调节的 衣原体侵入体的组分;和III）确定摄取后肌动蛋白的机制， 招聘目标是详细了解TarP的功能和调节，以指导 合理的药物和疫苗设计来对抗衣原体感染。

PROJECT SUMMARY Chlamydia trachomatis is the etiologic agent of the most prevalent sexually transmitted infection (STI) in industrialized nations and the blinding condition, trachoma, in under-developed countries. There is an estimated 93 million new reported cases of Chlamydia STI annually worldwide. Trachoma affects approximately 150 million individuals, predominantly women and children. The pathologic hallmark of both diseases is the scarring the results from chronic inflammation; and inflammation at the very early stages of infection is initiated by infection of epithelial cells, and sustained by active bacterial replication and dissemination along the genital and ocular mucosae. Chlamydia is a Gram-negative obligate intracellular pathogen, which means that it requires an intracellular environment for its survival and replication. Hence, invasion of a permissive host cell is paramount to its survival and pathogenesis. In vivo, the primary target is the epithelial cells that line the ocular and genital mucosae. Our overarching hypothesis is that invasion is a Chlamydia-driven process. This pathogen has evolved mechanisms of manipulating the host cell actin cytoskeleton of to induce its uptake, leading to the formation of cell surface structures designed to engulf the bacteria. Invasion involves a number of signaling pathways that in normal cells play a role in regulating actin cytoskeleton dynamics. The bacteria turns on the machinery at its site of adherence, with the location of actin remodeling determined by the restricted translocation of a chlamydial virulence protein called TarP to the cytosolic side of the host cell plasma membrane. TarP recruits a number of signaling molecules to initiate the remodeling of the actin cytoskeleton, followed by the engulfment of the pathogen. Once inside the cell, the pathogen has the opportunity to hijack other cellular processes, including the initiation of inflammation, which when sustained leads to tissue damage and scarring of the ocular conjunctiva the genital tract resulting in infertility. Thus, the ability of Chlamydia to cause disease starts with invasion. While we have a better understanding of TarP function during invasion, mechanistic details on how it is regulated is sparse. This application will investigate the role of mechanotransduction in regulating TarP interactions with host signaling molecules. The following Specific Aims will be addressed. I) To identify the mechanism and significance of TarP mechanosensing in invasion; II) To define the myosin II-regulated components of the chlamydial invasome; and III) To determine the mechanism of uptake post-actin recruitment. The goal is to obtain a detailed understanding of TarP function and regulation in order to guide rational drug and vaccine designs to combat Chlamydia infections.