Mechanisms underlying adhesion and colonization in pneumococcal keratitis

肺炎球菌角膜炎粘附和定植的机制

• 批准号: 10727764
• 负责人: Brian Akerley
• 金额: $ 42.63万
• 依托单位: UNIVERSITY OF MISSISSIPPI MED CTR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10727764
• 关键词: Adhesions; Anabolism; Antibiotic Resistance; Antibiotics; Automobile Driving; Bacteria; Bacterial Adhesins; Bacterial Attachment Site; Bacterial Capsules; Blindness; Cells; Cellular Assay; Clinical; Complement; Cornea; Data; Development; Disease; Epithelial Cells; Exercise; Eye; Eye Infections; Future; Gene Deletion; Genes; Genetic; Genetic Screening; Goals; Human; Immune system; In Vitro; Infection; Keratitis; Knowledge; Libraries; Mediating; Methods; Modeling; Mus; Mutation; Organism; Pathogenesis; Pneumococcal vaccine; Pneumonia; Polysaccharides; Predisposition; Process; Production; Regulation; Repression; Research; Resolution; Septicemia; Streptococcus pneumoniae; Surface; Testing; Validation; Virulence Factors; Vision; Visual impairment; Work; capsule; corneal epithelium; gene product; genomic locus; in vivo; mouse model; mutant; novel therapeutic intervention; novel therapeutics; ocular surface; preservation

Project Summary/Abstract Streptococcus pneumoniae is one of the top bacterial causes of keratitis worldwide and can lead to significant vision loss. The mainstay of therapy continues to be antibiotics; however, bacteria are not always susceptible, and antibiotics are unable to reduce the host- and bacterium-mediated damage associated with S. pneumoniae keratitis. Our findings strongly indicate that the outer polysaccharide capsule of S. pneumoniae, considered a major virulence factor of this organism, impedes attachment of the bacteria to the corneal surface. Preliminary data show that the bacteria produce markedly less capsule when adhered to corneal epithelial cells, which suggest that they regulate capsule to adapt to the corneal niche. Therefore, our central hypothesis is that S. pneumoniae adapts to down-regulate capsule in the present of corneal cells so that attachment and persistence are increased. We will test our hypothesis by comparing capsule quantities of bacteria that are adherent to corneal cells and the corneal surface to bacteria that are not adherent. We will then determine the genes that are necessary for corneal attachment and colonization by a prioritized genetic screen of a library of mutants in vitro and in vivo, followed by validation with functional analyses with targeted mutations. The long- term goals of this study are to identify and characterize the factors that repress bacterial capsule in the cornea and promote attachment to cause keratitis. Understanding the processes of regulation and colonization will aid in driving development of novel therapies to preserve the cornea.

项目概要/摘要 肺炎链球菌是世界范围内引起角膜炎的主要原因之一，可导致严重的角膜炎。 视力丧失。治疗的支柱仍然是抗生素；然而，细菌并不总是敏感的， 抗生素无法减少与肺炎链球菌相关的宿主和细菌介导的损害 角膜炎。我们的研究结果强烈表明，肺炎链球菌的外多糖荚膜被认为是 该生物体的主要毒力因子，阻碍细菌附着到角膜表面。初步的 数据显示，当细菌粘附在角膜上皮细胞上时，产生的荚膜明显减少，这 建议他们调节胶囊以适应角膜生态位。因此，我们的中心假设是 S. 肺炎链球菌适应下调角膜细胞存在的囊膜，以便附着和 持久性增加。我们将通过比较胶囊中细菌的数量来检验我们的假设 粘附于角膜细胞，而角膜表面则粘附于不粘附的细菌。然后我们将确定 通过对库进行优先遗传筛选，获得角膜附着和定植所必需的基因 体外和体内突变体，然后通过靶向突变的功能分析进行验证。长- 这项研究的长期目标是确定和描述抑制角膜细菌荚膜的因素 并促进附着引起角膜炎。了解监管和殖民化的过程将有助于 推动保护角膜的新疗法的开发。