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: 10301639
• 负责人: Xin M Luo
• 金额: $ 19.14万
• 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 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10301639
• 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 TLR5 激活驱动自身免疫 项目概要 肠上皮内层及其分泌的因子形成一道屏障，将宿主与肠壁分开。 在病理条件下，上皮内层的渗透性可能会受到损害。 管腔内容物进入血流，在具有遗传基因的个体中形成“肠漏”。 易感性，肠漏可能会让共生细菌和/或细菌成分进入体内， 触发自身免疫性疾病（SLE）的发生和发展是一种复杂的疾病。 尽管经过数十年的研究，系统性红斑狼疮的发病机制仍表现在多个器官。 近年来，我们和其他人已经发现 SLE 存在肠漏症，但这一点仍不清楚。 肠漏可能导致细菌脂多糖水平升高。 在 SLE 患者和狼疮易感小鼠的血液中都观察到了 (LPS) 内毒素，这支持了这一点 然而，目前尚不清楚肠漏如何促进 SLE 的发生和/或发展。 外源性 LPS 已被证明可促进小鼠狼疮，令人惊讶的是，Toll 样受体 4（TLR4，即 LPS 受体）并不能减轻狼疮倾向的 MRL/lpr 小鼠的疾病。 我们寻求研究可能引发系统性自身免疫的其他细菌成分的作用 在初步研究中，我们发现在遗传上易患狼疮的小鼠中，其水平显着升高。 SLE 患者和 MRL/lpr 小鼠的循环中都存在抗鞭毛蛋白抗体。 漏肠可能导致有鞭毛的细菌和/或鞭毛蛋白在肠道中易位 上皮并进入循环。鞭毛蛋白以及抗鞭毛蛋白免疫复合物（由形成） 抗原及其特异性抗体）可能会激活 TLR5（鞭毛蛋白受体），以驱动 炎症导致系统性自身免疫，因此，我们认为肠漏会导致系统性红斑狼疮。 我们提出了两个具体目标。 为了在 MRL/lpr 中检验这一假设，目标 1 是确定遗传性 SLE 小鼠模型的能力。 目的 2 是证明 SLE 发展缺乏。 通过使用尖端的 CRISPR/Cas9 技术，我们旨在揭示 Tlr5 缺失的机制。 肠漏会驱动自身免疫，并为设计新型治疗方法提供科学依据 对抗系统性红斑狼疮，目标是恢复肠道屏障功能。