Pathogensis of Bacterial corneal infection

细菌性角膜感染的发病机制

• 批准号: 7923869
• 负责人: Gerald B Pier
• 金额: $ 40.23万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7923869
• 关键词: Address; Animal Model; Antibodies; Applications Grants; Bacteria; Basic Science; Binding; Biological Preservation; Blindness; Cell Line; Cell membrane; Cell surface; Cells; Clinical Data; Conjugate Vaccines; Cornea; Corneal Injury; Cystic Fibrosis Transmembrane Conductance Regulator; Epithelial Cells; Evaluation; Eye; Eye Infections; Eye diseases; Funding; Goals; Host Defense; Human; Immune; Immune response; Immunity; Immunization; Immunotherapeutic agent; Immunotherapy; In Vitro; Individual; Infection; Inflammation; Inflammatory; Inflammatory Response; Intervention; Keratitis; Lead; Leucocidin; Ligands; Lipopolysaccharides; Membrane Lipids; Membrane Microdomains; Microbe; Modeling; Molecular; Mus; Oligosaccharides; Oryctolagus cuniculus; Outcome; Panton-Valentine leukocidin; Pathogenesis; Pathology; Patients; Polysaccharides; Prevention; Proteins; Pseudomonas aeruginosa; Regulatory T-Lymphocyte; Research; Role; Serum; Small Interfering RNA; Specificity; Staphylococcus aureus; Surface; Therapeutic; Transgenic Mice; Treatment Efficacy; Treatment outcome; Vaccination; Vaccines; Virulence; Virulence Factors; Vision; Visual Acuity; Work; antimicrobial; clinically significant; corneal epithelium; cystic fibrosis patients; cytotoxic; gene synthesis; human monoclonal antibodies; improved; injured; insight; methicillin resistant Staphylococcus aureus; microbial; pathogen; poly-N-acetyl glucosamine; polyclonal antibody; pre-clinical; prevent; prophylactic; public health relevance; receptor; research clinical testing; response; tissue culture; transcription factor; vaccine candidate

DESCRIPTION (provided by applicant): The broad, long term goals of this grant application are to understand the molecular and cellular host responses to bacterial pathogens that are significant causes of corneal infection. Specifically, this application will focus on infections caused by Pseudomonas aeruginosa and Staphylococcus aureus. These two pathogens are among the most common causes of serious corneal infections. Strains of both pathogens have acquired significant means to resist antimicrobial therapies and elaborate a large armamentarium of virulence factors that contribute to corneal damage and loss of visual acuity. Therapies for these infections need to both reduce bacterial numbers and allow the host to have an adequate and helpful inflammatory response to clear pathogens without causing damage to the cornea. For P. aeruginosa, most of the bacteria infecting scratch-injured mouse eyes are found inside of cells, and entry requires binding to the cystic fibrosis transmembrane conductance regulator (CFTR). This leads to initiation of inflammation, including activation of transcription factors for pro-inflammatory genes, synthesis of the pro-inflammatory molecules, and initiation of the cellular influx, primarily composed of PMNs, that will both clear the pathogen but can also cause damage to the cornea. PMN influx is also controlled by the TH17 regulatory T cell network, which will also be investigated in these studies. To determine how CFTR coordinates inflammation, we will analyze the specific effectors produced by cells with wild-type CFTR that are infected with P. aeruginosa, compare these with cells lacking CFTR, and validate in animal models of corneal infection the role of the CFTR-dependent factors in bacterial clearance and corneal pathology. For S. aureus, the recent dramatic increase in methicillin-resistant S. aureus (MRSA), particularly strains elaborating the Pantone-Valentine leukocidin (PVL), makes this pathogen a significant concern as a cause of serious eye disease. The role of PVL, and antibody to PVL which is found commonly in normal human sera, will be examined in tissue culture and murine models of infection using isogenic S. aureus strains positive or negative for PVL expression, as well as immunizing mice with the PVL components to analyze how antibody modulates the course of infection. These studies should also be informative about the general role leukocidins have in the pathogenesis of S. aureus corneal infections. Further studies on MRSA strains will extend to the potential of a candidate vaccine for S. aureus infections, utilizing the poly-N-acetyl glucosamine (PNAG) surface polysaccharide as the active component of a conjugate vaccine, to ameliorate the consequences of infection. Active vaccination, as well as passive transfer studies using both polyclonal antibodies and a fully human monoclonal antibody, will be evaluated in the murine model of corneal injury to determine if PNAG is a rationale target for immunotherapy of S. aureus corneal infection. The proposed studies should ex- tend our insights into the mechanisms of bacterial virulence and effective host defense for corneal infections and provide pre-clinical data for vaccine approaches to S. aureus that could be highly effective. PUBLIC HEALTH RELEVANCE: Infections of the eye surface (cornea) are the most significant cause of loss of vision and visual acuity in the world. Bacterial pathogens are very important causes of these infections, and among the most common are Pseudomonas aeruginosa and Staphylococcus aureus. This application will study how these microbes cause damage to the cornea that can result in vision loss and evaluate interventions, including vaccines, that could be used to prevent or treat these infections and minimize damage to the cornea and thus to an individual's eyesight.

描述（由申请人提供）：该赠款应用的广泛，长期目标是了解分子和细胞宿主对细菌病原体的反应，这是角膜感染的重大原因。具体而言，该应用将集中于铜绿假单胞菌和金黄色葡萄球菌引起的感染。这两种病原体是严重角膜感染的最常见原因之一。两种病原体的菌株均获得了抵抗抗菌疗法的重要手段，并阐述了大量的毒力因子的大量信念，这些因子有助于角膜损伤和视力丧失。这些感染的疗法既需要减少细菌数量，又使宿主对清除病原体具有适当且有用的炎症反应，而不会损害角膜。对于铜绿假单胞菌，在细胞内发现了大多数感染刮擦的小鼠眼睛的细菌，并且进入需要与囊性纤维化跨膜电导调节剂（CFTR）结合。这导致炎症的引发，包括激活促炎基因的转录因子，促炎分子的合成以及主要由PMN组成的细胞涌入的启动，这两个都将清除病原体，但也可能对角膜造成损害。 PMN涌入也受TH17调节性T细胞网络的控制，这些研究也将在这些研究中进行研究。为了确定CFTR如何辅化炎症，我们将分析由野生型CFTR的细胞产生的特定效应子，这些特定效应子被铜绿假单胞菌感染，将它们与缺乏CFTR的细胞进行比较，并在角膜感染的动物模型中验证CFTR依赖性因子在细菌清除和毛层病理学中的作用。对于金黄色葡萄球菌而言，最近耐甲氧西林的金黄色葡萄球菌（MRSA）的急剧增加，尤其是对Pantone-valentine Leukocidin（PVL）阐述的菌株，使该病原体成为严重眼科病的重要原因。 PVL和对PVL的抗体的作用通常在正常人血清中发现，将在组织培养和使用ISEGENIC S. AUREUS菌株阳性或阴性的PVL表达中进行感染和鼠类感染模型中进行检查，并用PVL成分对小鼠进行免疫，以分析抗体如何调节感染过程。这些研究还应该了解白细胞在金黄色葡萄球菌感染的发病机理中的一般作用。对MRSA菌株的进一步研究将扩展到金黄色葡萄球菌感染的候选疫苗的潜力，利用多聚-N-乙酰葡萄糖（PNAG）表面多糖作为结合疫苗的活性成分，以改善感染的后果。主动疫苗接种以及使用多克隆抗体和完全人类单克隆抗体的被动转移研究将在角膜损伤的鼠模型中进行评估，以确定PNAG是否是aureus角膜链球菌感染的免疫疗法的靶标。拟议的研究应阐述我们对细菌毒力和有效宿主防御的角膜感染机制的见解，并为金黄色葡萄球菌的疫苗方法提供临床前数据，这可能是非常有效的。公共卫生相关性：眼表（角膜）的感染是世界上视力和视力丧失的最重要原因。细菌病原体是这些感染的非常重要的原因，其中最常见的是铜绿假单胞菌和金黄色葡萄球菌。该应用将研究这些微生物如何对角膜造成损害，从而导致视力丧失并评估包括疫苗在内的干预措施，这些干预措施可用于预防或治疗这些感染，并最大程度地减少对角膜的损害，从而使人视力。