权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Mechanisms of flagellin induced protection against bacterial keratitis

鞭毛蛋白诱导预防细菌性角膜炎的机制

基本信息

批准号：
8332413
负责人：
Fu-Shin X Yu
金额：
$ 36.84万
依托单位：
WAYNE STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-05-01 至 2012-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8332413
关键词：
Adjuvant Therapy Adrenal Cortex Hormones Anti-Inflammatory Agents Anti-inflammatory Antibiotics Antimicrobial Resistance Attenuated Bacterial Infections Biological Assay Blindness C57BL/6 Mouse Cell surface Cells Clinical Trials Coculture Techniques Contact Lenses Cornea Corneal Diseases Data Development Disease Outbreaks Down-Regulation Epidermal Growth Factor Receptor Epithelial Epithelial Cells Exposure to Family member Feedback Flagella Flagellin Genes Gram-Negative Bacteria Health Host Defense Human IRAK1 gene IRAK3 gene IRAK4 gene In Vitro Infection Infection prevention Infectious Agent Infiltration Inflammation Inflammatory Inflammatory Response Invaded Keratitis Knockout Mice Laboratory Study Lead MAPK14 gene MAPK8 gene Maintenance Measures Mediating Modeling Mus Neutrophil Infiltration Outcome PI3K/AKT Pathway interactions Patients Perforation Phenotype Play Prevention Production Prophylactic treatment Protein Family Pseudomonas Pseudomonas Infections Pseudomonas aeruginosa Regimen Resolution Role Signal Pathway Signal Transduction Small Interfering RNA Solutions Stromal Cells Structural Protein TRAF6 gene Testing Therapeutic Tissues Toll-Like Receptor 5 Trauma Vision antimicrobial base chemokine corneal epithelium corneal scar cytokine design exposed human population improved in vivo inhibitor/antagonist interleukin-1 receptor-associated kinase killings lipoxin A4 microbial migration mouse model neutrophil novel novel strategies pathogen prevent prophylactic response

项目摘要

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa keratitis is a sight-threatening corneal disease associated with trauma and contact-lens wearing. Although an antibiotic regimen can eliminate the infectious organisms, the host inflammation that occurs, if not suppressed, can cause corneal scarring that can potentially lead to permanent vision loss in some patients. Previous studies from the laboratory revealed that human corneal epithelial cells (HCECs) sense Pseudomonas via recognition of flagellin, the structural protein of bacterial flagella, by Toll-like receptor-5 (TLR5) and respond to Pseudomonas-challenge by producing pro-inflammatory cytokines. To date, how the corneal inflammatory response is modulated after TLR stimulation is largely unresolved. We recently discovered that a prior exposure to flagellin resulted in cell reprogramming, as manifested by decreased production of pro-inflammatory cytokines and augmented expression of antimicrobial molecules in HCECs and in development of protective mechanisms, including enhanced bacterial clearance and downregulated expression of cytokines/chemokines, and accelerated inflammation resolution in the cornea of Pseudomonas-infected C57BL/6 (B6) mice. We hypothesize that TLR-mediated epithelial reprogramming is a key determinant of corneal innate defense and the underlying mechanisms can be exploited as novel approaches for anti-inflammatory and/or anti-infection therapies. To understand flagellin-induced cell reprogramming and ocular protective mechanisms, we propose the following Specific Aims: 1) To assess how the TLR5-mediated signaling pathways are modulated by the IRAK family of proteins and PI3K/AKT and what roles they play in acquiring tolerance phenotype in HCECs. This will be achieved by using siRNA and specific inhibitors to define the role of signal transducing molecules of the TLR-pathway in HCEC reprogramming and its consequences in vitro. 2) To determine how flagellin-induced epithelial reprogramming differentially regulates the expression of antimicrobial genes and modulates neutrophil infiltration and stromal cell activation in the cornea in response to Pseudomonas infection. This will be done using in vitro bacterial killing assay and co-culture of epithelial-neutrophil and epithelial-stromal cells. 3) To exploit the underlying mechanisms of tolerance/reprogramming as novel approaches for anti-inflammatory and anti-infection therapies in murine model of Pseudomonas keratitis. C57BL/6 mouse model of Pseudomonas keratitis, along with gene knockout mice, will be used to test this hypothesis and to determine therapeutic potential of flagellin in preventing infection- and inflammation-caused corneal tissue damage. The results of this study will provide a logical basis for the design of novel anti-inflammatory and anti-infection therapies for prophylaxis and/or treatment of bacterial keratitis. PUBLIC HEALTH RELEVANCE. This study explores the possibility of using flagellin as a prophylactic measure to prevent microbial keratitis and as an adjuvant therapy to traditional antibiotic regimen to suppress the ongoing inflammation after bacterial infection of the cornea. In the light of emerging antimicrobial resistance, the controversial role of corticosteroids, and an increased outbreak of contact solution-associated microbial keratitis, this study is of paramount importance and may lead to clinical trials for the use of flagellin in preventing and/or treating infectious keratitis.

描述(申请人提供)：铜绿假单胞菌角膜炎是一种与外伤和配戴隐形眼镜有关的威胁视力的角膜疾病。虽然抗生素疗法可以消除感染性微生物，但如果不加以抑制，宿主炎症可能会导致角膜瘢痕形成，可能会导致某些患者永久失明。实验室以往的研究表明，人角膜上皮细胞通过Toll样受体-5(TLR5)识别细菌鞭毛的结构蛋白鞭毛蛋白来感知假单胞菌，并通过产生促炎细胞因子来响应假单胞菌的挑战。到目前为止，TLR刺激后角膜炎症反应是如何调节的在很大程度上还没有解决。我们最近发现，预先接触鞭毛蛋白会导致细胞重新编程，表现为HCECs中促炎细胞因子的产生减少和抗菌分子的表达增加，以及保护机制的发展，包括增强细菌清除和下调细胞因子/趋化因子的表达，以及加速感染假单胞菌感染的C57BL/6(B6)小鼠角膜的炎症消退。我们假设TLR介导的上皮重编程是角膜固有防御的关键决定因素，其潜在机制可被用作抗炎和/或抗感染治疗的新方法。为了了解鞭毛蛋白诱导的细胞重编程和眼睛保护机制，我们提出了以下具体目标：1)评估TLR5介导的信号通路如何受到IRAK家族蛋白和PI3K/AKT的调节，以及它们在获得HCECs耐受表型中所起的作用。这将通过使用siRNA和特定的抑制剂来确定TLR途径的信号转导分子在HCEC重新编程中的作用及其在体外的后果来实现。2)研究鞭毛蛋白诱导的角膜上皮细胞重编程对感染假单胞菌后角膜中性粒细胞的侵袭和基质细胞活化的影响。这将使用体外细菌杀灭试验和上皮中性粒细胞和上皮基质细胞的共培养来完成。3)探索耐受/重编程的潜在机制，作为小鼠假单胞菌角膜炎模型抗炎和抗感染治疗的新途径。C57BL/6假单胞菌角膜炎小鼠模型以及基因敲除小鼠将用于验证这一假说，并确定鞭毛蛋白在预防感染和炎症引起的角膜组织损伤方面的治疗潜力。这项研究的结果将为设计预防和/或治疗细菌性角膜炎的新型抗炎和抗感染疗法提供逻辑基础。与公共卫生相关。本研究探讨了使用鞭毛蛋白作为预防微生物角膜炎的预防措施以及作为传统抗生素方案的辅助治疗以抑制角膜细菌感染后持续炎症的可能性。鉴于新出现的抗菌素耐药性，皮质类固醇的有争议的作用，以及接触液相关微生物角膜炎的增加，这项研究具有至关重要的意义，并可能导致使用鞭毛蛋白预防和/或治疗感染性角膜炎的临床试验。