Mechanisms of flagellin-induced protection against microbial keratitis

鞭毛蛋白诱导的微生物性角膜炎保护机制

• 批准号: 8248480
• 负责人: Fu-Shin X Yu
• 金额: $ 38万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8248480
• 关键词: Acetylation; Adjuvant; Anti-Inflammatory Agents; Anti-inflammatory; Antibiotic Resistance; Aspergillus; Biological Assay; Blindness; Bone Marrow; Candida; Candida albicans; Cells; Chromatin; Cornea; Data; Dendritic Cells; Development; Epithelial; Epithelial Cells; Epithelium; Flagellin; Gene Expression; Genes; Genomics; Goals; Grant; Histone Deacetylase Inhibitor; Homeostasis; Hour; Immune; Immune response; Infection; Inflammation; Inflammation Mediators; Inflammatory; Invaded; Keratitis; Knock-out; Knockout Mice; Knowledge; Lead; Ligands; Light; Mediating; Mediator of activation protein; Methods; Modality; Modeling; Molecular Structure; Mucosal Immunity; Mus; Myeloid Cells; Natural Immunity; Neutrophil Infiltration; Play; Production; Pseudomonas aeruginosa; Recovery of Function; Recruitment Activity; Regulation; Resistance; Resistance to infection; Role; Severities; Signal Transduction; Small Interfering RNA; TLR2 gene; Testing; Therapeutic; Toll-Like Receptor 5; Toll-like receptors; Topical application; Transgenic Mice; activating transcription factor 3; antimicrobial peptide; base; cathelicidin; chemokine; chromatin immunoprecipitation; chromatin modification; chromatin remodeling; corneal epithelium; cytokine; innovation; macrophage; microbial; mouse model; neutrophil; ocular surface; pathogen; prevent; promoter; prophylactic; reconstitution; response; transcription factor

DESCRIPTION (provided by applicant): Microbial keratitis is a common cause of vision loss. The cornea is exquisitely sensitive to inflammation- mediated damage and therefore has strong innate defenses. However, when the epithelial barrier function is breached, opportunistic bacterial and fungal pathogens can gain access to the epithelial cell layers and colonize in the cornea, leading to infection. During the initial grant period, flagellin, the ligand of Toll-like receptor 5 (TLR5), was used to fortify corneal innate immunity and render resistance to a broad spectrum of keratitis causing pathogens, including Pseudomonas aeruginosa, Candida albicans and Aspergillus fumigates. This highly inducible and robust innate mucosal protection can be attributed to flagellin-induced genomic reprogramming in the epithelium which, in turn, interacts with professional immune cells to control inflammation and to eradicate invading pathogens. The hypothesis in this application is that flagellin, through TLR5, stimulates protective corneal innate mucosal immunity that involves epithelial cells, infiltrated PMNs, and activated dendritic cells, collectively conferring robust resistance to microbial keratitis. Three specific aims are proposed to test this hypothesis: 1) To determine how flagellin-induced reprogramming is regulated in corneal epithelial cells and in the cornea. This can be assessed by using the chromatin immunoprecipitation assay and histone deacetylase inhibitors for gene-specific chromatin modification and by using siRNA and knockout mice for delineating the role of activating transcription factor-3, a transcription factor induced by fg, in regulating the innate immune response in the cornea. 2) To determine how the epithelium participates in and coordinates flagellin-induced mucosal innate immune defense against microbial keratitis. The role of the epithelium and its interaction with dendritic cells in innate defense will be determined by using various transgenic and knockout mice, bone marrow reconstitution, and cell depletion. 3) To determine how flagellin induces protection against non-flagellated pathogens in the cornea. The therapeutic potential of flagellin and its mechanisms of action will be characterized by using mouse models of fungal keratitis (Candida and Aspergillus as pathogens and post-infection topical flagellin application) and double TLR knockout mice. The results of the proposed study should shed light on corneal innate immunity and its induction, and may lead to the development of new prophylactic/therapeutic modalities for preventing and treating microbial keratitis. PUBLIC HEALTH RELEVANCE: This proposal is to determine the mechanisms underlying flagellin-induced protective corneal mucosal immunity and to explore its therapeutic potential to treat microbial keratitis, a common cause of vision loss. The knowledge gained will be critical for the long-term goal of developing mechanism-based, efficacious prophylactic/therapeutic modalities for preventing and treating infectious keratitis.

描述（由申请人提供）：微生物角膜炎是视力丧失的常见原因。角膜对炎症介导的损伤非常敏感，因此具有强大的先天防御能力。但是，当破坏上皮屏障功能时，机会性细菌和真菌病原体可以进入上皮细胞层并在角膜中定植，从而导致感染。在最初的赠款期间，鞭毛蛋白，Toll样受体5（TLR5）的配体用于增强角膜先天免疫，并具有对广泛的角膜炎的抵抗力，导致病原体，包括pseudomonas aeruginosa，candidaosa，candida obigina，念珠菌和烟草烟草。这种高度诱导和强大的先天粘膜保护可以归因于上皮中鞭毛蛋白诱导的基因组重编程，进而与专业的免疫细胞相互作用以控制炎症并消除入侵的病原体。该应用中的假设是，鞭毛蛋白通过TLR5刺激了涉及上皮细胞，浸润PMN和活化的树突状细胞的保护性角膜先天粘膜免疫，从而统治对微生物角膜炎的耐药性。提出了三个特定的目的来检验这一假设：1）确定在角膜上皮细胞和角膜中如何调节鞭毛蛋白诱导的重编程。这可以通过使用染色质免疫沉淀测定法和组蛋白脱乙酰基酶抑制剂进行基因特异性染色质修饰，并使用siRNA和基因敲除小鼠来描述激活转录因子-3的作用，这是一种由FG诱导的转录因子，在调节角球中的天生免疫反应中。 2）确定上皮如何参与并协调鞭毛蛋白诱导的粘膜先天性免疫防御微生物角膜炎。上皮的作用及其与树突状细胞在先天防御中的相互作用将通过使用各种转基因和敲除小鼠，骨髓重建和细胞耗竭来确定。 3）确定鞭毛蛋白如何诱导角膜中非鞭毛病原体的保护。通过使用真菌角膜炎的小鼠模型（念珠菌和曲霉作为病原体和感染后鞭毛蛋白的应用）和双TLR敲除小鼠，鞭毛蛋白及其作用机理的治疗潜力及其作用机理。拟议的研究的结果应阐明角膜先天免疫及其诱导，并可能导致开发新的预防/治疗方式，以预防和治疗微生物角膜炎。 公共卫生相关性：该建议是确定鞭毛蛋白引起的保护性角膜粘膜免疫的基础机制，并探索其治疗微生物角膜炎的治疗潜力，这是视力丧失的常见原因。获得的知识对于开发基于机制的，有效的预防/治疗方式的长期目标至关重要，以预防和治疗感染性角膜炎。