P. aeruginosa type III secreted effectors in corneal disease

角膜疾病中铜绿假单胞菌 III 型分泌效应子

• 批准号: 8217524
• 负责人: Arne Rietsch
• 金额: $ 39.25万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8217524
• 关键词: ADP Ribose Transferases; Acute; Address; Animal Model; Bacteria; Blindness; Cells; Complement; Contact Lenses; Cornea; Corneal Diseases; Corneal Stroma; Data; Development; Disease; Disease Progression; Dose; Enzymes; Epithelial Cells; Extended-Wear Contact Lenses; Eye Infections; Eye Injuries; Genome; Grant; Immune; Immune response; Immune system; Individual; Infection; Infection prevention; Invaded; Keratitis; Lead; Left; Link; Lung; Mediating; Modeling; Molecular; Mus; Neutrophil Infiltration; Organism; Pathogenesis; Patients; Peptide Hydrolases; Phenotype; Phospholipase; Pilum; Positioning Attribute; Production; Properdin; Proteins; Pseudomonas aeruginosa; Reporting; Research; Role; Severity of illness; Shapes; Signal Transduction; Site; Staging; Syringes; TLR4 gene; TLR5 gene; Toll-like receptors; Type III Secretion System Pathway; Virulence; Virulence Factors; Visual impairment; bacterial genetics; chemokine; combat; corneal epithelium; cytotoxic; design; extracellular; in vivo; killings; macrophage; microbial; neutrophil; prevent; research study; rho; uptake

DESCRIPTION (provided by applicant): P. aeruginosa infections are a common cause of corneal disease associated with extended-wear contact lens use here in the US. One of the primary virulence factors P. aeruginosa uses to promote disease is its type III secretion system, a molecular syringe that allows the bacterium to directly inject effector proteins into targeted host cells. The role of type III secretion in corneal disease has not been studied extensively, but initial reports suggest that corneal disease depends on the complement of effectors being expressed by the infecting bacteria. "Cytotoxic" strains expressing the potent phospholipase ExoU rely extensively on type III secretion to promote disease, whereas ExoS-producing "invasive" strains appear to not rely on type III secretion in order to elicit corneal disease. We have revisited the role of type III secretion in the pathogenesis of corneal disease elicited by ExoS+ "invasive" isolates of P. aeruginosa. Our preliminary data demonstrates that corneal disease relies critically on type III secretion and on the two effectors ExoS and ExoT, in particular. In addition, we provide evidence that the primary role of type III secretion in corneal disease is to stave off killing by infiltrating neutrophils. Accordingly, the focus of this proposal is to determine the role of the individual enzymatic activities of ExoS and ExoT in preventing clearance by neutrophils in vivo. We will correlate these findings with experiments aimed at examining the role of ExoS and ExoT in preventing phagocytic killing by isolated primary neutrophils. We will also examine the difference in pathogenesis between ExoU-expressing "cytotoxic" and ExoS-expressing "invasive" strains of P. aeruginosa in order to determine if any differences can be directly linked to the activities of these two effectors. Understanding the role of effector proteins in corneal disease is an important step towards formulating new strategies for preventing and treating P. aeruginosa infections of the eye. PUBLIC HEALTH RELEVANCE: Pseudomonas aeruginosa is a common cause of eye infections, particularly in contact lens wearers. If left untreated these infections can result in rapid loss of vision. The bacterium injects toxic proteins into host immune cells that normally engulf and kill the invading bacteria. Our research is aimed at understanding how these toxic proteins stave off killing by the host immune system, with the hope that a better understanding of their function will lead to the design of targeted therapies to combat or prevent these infections.

描述（由申请方提供）：铜绿假单胞菌感染是美国长期配戴接触透镜相关角膜疾病的常见原因。铜绿假单胞菌用于促进疾病的主要毒力因子之一是其III型分泌系统，这是一种分子注射器，允许细菌将效应蛋白直接注射到靶向宿主细胞中。III型分泌物在角膜疾病中的作用尚未得到广泛研究，但初步报告表明，角膜疾病取决于感染细菌表达的效应子的补充。表达强效磷脂酶ExoU的"细胞毒性"菌株广泛依赖于III型分泌来促进疾病，而产生ExoS的"侵入性"菌株似乎不依赖于III型分泌来引发角膜疾病。 我们已经重新审视了III型分泌物在由铜绿假单胞菌的ExoS +"侵袭性"分离株引起的角膜疾病发病机制中的作用。我们的初步数据表明，角膜疾病严重依赖于III型分泌，特别是两种效应子ExoS和ExoT。此外，我们提供的证据表明，在角膜疾病中，III型分泌物的主要作用是避免浸润中性粒细胞的杀伤。因此，本提案的重点是确定ExoS和ExoT的单个酶活性在体内防止中性粒细胞清除中的作用。我们将这些发现与旨在检查ExoS和ExoT在防止分离的原代中性粒细胞吞噬杀伤中的作用的实验相关联。我们还将研究表达ExoU的"细胞毒性"和表达ExoS的"侵袭性"铜绿假单胞菌菌株之间的发病机制差异，以确定是否有任何差异与这两种效应物的活性直接相关。 了解效应蛋白在角膜疾病中的作用是制定预防和治疗眼部铜绿假单胞菌感染的新策略的重要一步。 公共卫生相关性：铜绿假单胞菌是眼部感染的常见原因，尤其是在接触透镜配戴者中。如果不及时治疗，这些感染会导致视力迅速丧失。这种细菌将有毒蛋白质注入宿主免疫细胞，这些细胞通常会吞噬并杀死入侵的细菌。我们的研究旨在了解这些有毒蛋白质如何避免宿主免疫系统的杀伤，希望更好地了解它们的功能将导致设计靶向治疗来对抗或预防这些感染。