Unraveling the contribution of gut microbiome in trichloroethene-mediated autoimmunity

摘要 三氯乙烯（三氯乙烯，TCE）是一种环境和职业性试剂，已知会导致 自身免疫性疾病（AD），包括人类的SLE样疾病。SLE的病因可能是多因素的， 包括基因荷尔蒙和环境因素越来越多的证据表明，环境 因素，包括微生物群的变化有助于AD。使用雌性MRL+/+小鼠，我们建立了 三氯乙烯导致疾病的早期诱发。我们对这些小鼠的初步研究也表明，TCE 暴露导致肠道微生物组生态失调沿着几种重要的细菌短链 脂肪酸（SCFAs）。然而，肠道微生物群导致TCE介导的 SLE的早期诱导是未知的，并且是本建议的主要焦点。我们将测试中央 假设遗传易感人群中的TCE暴露导致肠道微生物组生态失调， 肠道完整性受损以及粘膜免疫失调，导致全身性 自身免疫反应最终导致SLE为了实现我们了解角色的总体目标 TCE介导的SLE中的肠道微生物组，将追求以下具体目标。目标1将规定， TCE暴露通过肠道微生物群的生态失调引起其产生SLE的效应，而TCE引起的肠道微生物群 经处理的MRL+/+小鼠可将SLE表型传递给对照小鼠。使用粪便样本，16 S rRNA和 将进行宏基因组测序（WGS）以评估肠道微生物组的差异组成， 和功能基因的差异。此外，使用TCE处理小鼠的粪便， 移植（FMT）研究将在无菌小鼠中进行，这将坚定地建立改变的 微生物组在TCE介导的自身免疫中起致病作用。目标2将确定TCE-微生物组- 宿主相互作用通过影响肠道完整性和粘膜免疫而促成疾病结果。我们将 测量体内肠道通透性、紧密连接蛋白和循环中的内毒素水平。贡献 还将评估氧化应激对上皮通透性的影响。我们还将确定TCE治疗是否存在偏差， Treg-Th 17平衡向Th 17表型，沿着肠道炎性小体活化， 炎性细胞因子然后进行TdR的连续转移以恢复肠道稳态。目标3将 确定细菌SCFA的失衡是否通过影响粘膜免疫而导致SLE发病， 屏障功能，益生菌治疗可以通过恢复SCFA来改善TCE介导的自身免疫。我们 将检查疾病开始和进展期间SCFAs和粘膜T细胞的概况， 进行SCFAs和益生菌的补充研究，以进一步建立机制， 微生物群有助于TCE介导的SLE。成功地完成这些目标将建立因果关系 肠道微生物群失调在TCE介导的SLE中的作用，描述了导致疾病的新机制 致病机制，并帮助设计新的治疗性微生物靶点的自身免疫/SLE。

ABSTRACT Trichloroethene (trichloroethylene, TCE), an environmental and occupational agent, is known to cause autoimmune diseases (ADs), including SLE-like disease in humans. The etiology of SLE is likely multifactorial, which includes genetic, hormonal and environmental triggers. There is increasing evidence that environmental factors, including changes in microbiota contribute to ADs. Using female MRL+/+ mice, we have established that TCE causes early induction of the disease. Our preliminary studies in these mice also show that TCE exposure leads to gut microbiome dysbiosis along with decreases in several important bacterial short-chain fatty acids (SCFAs). However, the contribution and mechanisms by which gut microbiota lead to TCE-mediated early induction of SLE are not known, and are the major focus of this proposal. We will test the central hypothesis that TCE exposure in genetically susceptible populations causes gut microbiome dysbiosis and impaired intestinal integrity together with mucosal immune dysregulation, which contribute to systemic autoimmune responses and eventually lead to SLE. To achieve our overarching goal of understanding the role of gut microbiome in TCE-mediated SLE, the following specific aims will be pursued. Aim 1 will establish that TCE exposure causes its SLE-producing effects via dysbiosis of gut microbiota, and gut microbiota from TCE- treated MRL+/+ mice can transmit SLE phenotypes to control mice. Using fecal samples, 16S rRNA and metagenomic sequencing (WGS) will be performed to assess differential composition of the gut microbiome, and differences in the functional genes. Furthermore, using feces from TCE-treated mice, fecal microbiome transplant (FMT) studies will be performed in germ-free mice, which will firmly establish that altered microbiome plays a causative role in TCE-mediated autoimmunity. Aim 2 will determine if TCE-microbiome- host interactions contribute to disease outcome by affecting intestinal integrity and mucosal immunity. We will measure gut permeability in vivo, tight junction proteins and endotoxin levels in the circulation. Contribution of oxidative stress to epithelial permeability will also be assessed. We will also determine if TCE treatment skews the Treg-Th17 balance towards a Th17 phenotype, along with intestinal inflammasome activation and inflammatory cytokines. Adoptive transfer of Tregs will then be done to restore gut homeostasis. Aim 3 will determine if imbalances in bacterial SCFAs contribute to SLE pathogenesis by affecting mucosal immunity and barrier functions, and probiotic therapy can ameliorate TCE-mediated autoimmunity by restoring SCFAs. We will examine profiles of SCFAs and mucosal Tregs during initiation and progression of the disease, and conduct supplementation studies with SCFAs and probiotics to further establish the mechanisms by which microbiota contributes to TCE-mediated SLE. Successful completion of these aims will establish the causal role of gut microbiome dysbiosis in TCE-mediated SLE, delineate novel mechanisms contributing to disease pathogenesis, and help in designing novel therapeutic microbial targets for autoimmunity/SLE.