Leaky gut drives autoimmunity via bacterial flagellin-mediated activation of TLR5

肠漏通过细菌鞭毛蛋白介导的 TLR5 激活驱动自身免疫

• 批准号: 10408849
• 负责人: Xin M Luo
• 金额: $ 22.86万
• 依托单位: VIRGINIA POLYTECHNIC INST AND ST UNIV
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-21 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10408849
• 关键词: Alleles; Antibiotics; Antibodies; Antigen-Antibody Complex; Antigens; Attenuated; Autoimmune Diseases; Autoimmunity; Backcrossings; Bacteria; Blood; Blood Circulation; CRISPR/Cas technology; Complex; Data; Development; Disease; Endotoxins; Environment; Epithelial; Exhibits; Flagellin; Generations; Genetic Polymorphism; Genetic Predisposition to Disease; Goals; Human; Inbred MRL lpr Mice; Individual; Inflammation; Interferon-alpha; Investigation; Kidney; Leaky Gut; Lipopolysaccharides; Lupus; Lupus Nephritis; Mastigophora; Mediating; Mus; Oral; Organ; Pathogenesis; Pathogenicity; Pathologic; Patients; Peripheral Blood Mononuclear Cell; Permeability; Research; Role; SLEB1 gene; Saline; Signal Transduction; Stream; Susceptibility Gene; Systemic Lupus Erythematosus; TLR4 gene; TLR5 gene; Terminator Codon; Testing; Translations; commensal bacteria; design; gain of function; gut microbiota; high reward; high risk; intestinal barrier; intestinal epithelium; loss of function; lupus prone mice; mouse model; mutant; novel therapeutic intervention; receptor; restoration; systemic autoimmunity

Leaky gut drives autoimmunity via bacterial flagellin-mediated activation of TLR5 Project Summary The intestinal epithelial lining, together with factors secreted from it, forms a barrier that separates the host from the environment. In pathologic conditions, the permeability of the epithelial lining may be compromised allowing the passage of lumen contents to enter the blood stream creating a “leaky gut.” In individuals with a genetic predisposition, a leaky gut may allow commensal bacteria and/or bacterial components to enter the body and trigger the initiation and development of autoimmune disease. Systemic lupus erythematosus (SLE) is a complex autoimmune disease manifested in multiple organs. Albeit decades of investigation, the pathogenesis of SLE remains unclear. In recent years, we and others have hypothesized the presence of a leaky gut in SLE and that the leaky gut can contribute to the pathogenesis of the disease. Increased levels of bacterial lipopolysaccharide (LPS) endotoxin have been observed in the blood of both SLE patients and lupus-prone mice, supporting this hypothesis. However, it is unknown how a leaky gut can contribute to SLE initiation and/or development. While exogenous LPS has been shown to facilitate murine lupus, surprisingly, deletion of toll-like receptor 4 (TLR4, the receptor of LPS) did not attenuate disease in lupus-prone MRL/lpr mice. In this high risk-high reward proposal, we seek to investigate the role of other bacterial components that could potentially trigger systemic autoimmunity in mice genetically prone to develop lupus. In preliminary studies we discovered that significant higher levels of anti-flagellin antibodies are present in the circulation of both SLE patients and MRL/lpr mice. This indicates that the leaky gut may have allowed for translocation of flagellated bacteria and/or flagellin across the intestinal epithelium and into the circulation. Circulating flagellin as well as anti-flagellin immune complexes (formed by the antigen and its specific antibody) could potentially activate TLR5, the receptor of flagellin, to drive inflammation leading to systemic autoimmunity seen in SLE. Therefore, we hypothesize that a leaky gut leads to SLE-like autoimmunity through bacterial flagellin-mediated activation of TLR5. We propose two specific aims to test this hypothesis in MRL/lpr, a mouse model of genetically prone SLE. Aim 1 is to determine the capability of exogenous flagellin to facilitate systemic autoimmunity. Aim 2 is to demonstrate the lack of SLE development with Tlr5 deletion. Using the cutting-edge CRISPR/Cas9 technology, we aim to reveal a mechanism by which a leaky gut drives autoimmunity, and provide the scientific basis for the design of novel therapeutic approaches against SLE that target restoration of the intestinal barrier function.

肠漏通过细菌鞭毛蛋白介导的TLR 5激活驱动自身免疫 项目摘要 肠上皮衬里与其分泌的因子一起形成屏障，将宿主与 环境保护在病理条件下，上皮衬里的渗透性可能受到损害， 管腔内容物进入血流的通道，产生“肠漏”。在具有遗传基因的个体中， 易患病，肠漏可能允许肠道细菌和/或细菌成分进入体内， 引发自身免疫性疾病的发生和发展。系统性红斑狼疮（SLE）是一种复杂的 自身免疫性疾病表现在多个器官。尽管经过几十年的研究，SLE的发病机制 仍不清楚近年来，我们和其他人假设SLE患者存在肠漏， 肠漏可能导致该疾病的发病机制。细菌脂多糖水平升高 (LPS)在SLE患者和狼疮易感小鼠的血液中均观察到内毒素，这支持了 假说.然而，目前尚不清楚肠漏如何导致SLE的发生和/或发展。而 外源性LPS已显示促进鼠狼疮，令人惊讶的是，Toll样受体4（TLR 4， LPS的受体）并没有减轻狼疮易感MRL/lpr小鼠的疾病。在这个高风险高回报的提案中， 我们试图研究其他可能引发全身性自身免疫的细菌成分的作用， 遗传上容易患狼疮的老鼠。在初步研究中，我们发现， 抗鞭毛蛋白抗体存在于SLE患者和MRL/lpr小鼠的循环中。这表明 肠道渗漏可能使鞭毛细菌和/或鞭毛蛋白穿过肠道移位 上皮细胞并进入循环。循环鞭毛蛋白以及抗鞭毛蛋白免疫复合物（由 抗原及其特异性抗体）可以潜在地激活鞭毛蛋白的受体TLR 5， 炎症导致系统性自身免疫，见于SLE。因此，我们假设肠漏导致 SLE样自身免疫通过细菌鞭毛蛋白介导的TLR 5激活。我们提出两个具体目标 为了在MRL/lpr（一种遗传易感性SLE的小鼠模型）中检验这一假设。目标1是确定能力 外源性鞭毛蛋白，以促进系统性自身免疫。目的2是证明缺乏SLE发展 TLR 5缺失。使用最先进的CRISPR/Cas9技术，我们的目标是揭示一种机制， 漏肠驱动自身免疫，为设计新的治疗方法提供科学依据 针对SLE的靶向肠屏障功能的恢复。