Epigenetic modulation of CD4+ T cell differentiation and autoimmunity by trichloroethylene

项目总结 环境污染物三氯乙烯(TCE)促进自身免疫作用的研究 已经集中在狼疮易感小鼠的效应/记忆CD4+T细胞的功能效应上。我们的长期目标 是为了了解TCE如何促进CD4细胞分化以促进自身免疫和/或超敏反应 精神错乱。目的是(I)确定三氯乙烯如何通过其主要代谢物三氯乙醛 水合物(TCAH)，改变原始CD4细胞向效应/记忆亚群的分化，在促进 (如Th1和Th17)或体外抑制自身免疫(如Th2和Treg)和(Ii)确定 这些亚群在体内的致病性。CD4将在自身免疫倾向(MRL+/+)和 了解耐药(B6)品系小鼠遗传易感因素的贡献。两者都包括在内 性别可能揭示了为什么女性会增加自身免疫性疾病的风险。中心假设是TCAH 促进致病效应细胞的分化和/或减少效应细胞的扩张 与自身免疫抑制有关，包括基因表达和DNA甲基化的变化。 TCAH将产生独特的遗传特征，尽管将在MRL+/+小鼠中观察到免疫病理 而不是在B6小鼠身上，雌性比雄性更强健。理由是，它现在是显而易见的 可能在DNA甲基化水平上调节的关键的CD4功能效应发生在 因此，不能在已经分化的细胞中进行研究。核心假说将得到检验 在三个特定目标中：1)通过评估基因表达来确定TCAH对CD4+T细胞分化的影响 2)DNA甲基化；3)体内Th亚群分化的致病性测定。在第一个下 Am，RNA-Seq将确定TCAH是否直接改变可能赋予选择性 优势致病效应细胞为CD4+T细胞。在目标2中，减少代表性的亚硫酸盐排序将是 用于确定TCAH诱导分化的CD4+T细胞DNA甲基化的变化。实验将会 检测TCAH诱导的基因表达变化是否在DNA甲基化水平进行 甲基供体或甲基化抑制剂来逆转效果。重要的甲基变异的存在将会 用流式细胞仪测定。第三个目标是测试Th亚群产生免疫的能力 过继迁移实验中的病理学。在移植前用甲基供体处理细胞将与 目的1和2结果确定TCAH是否在DNA甲基化中促进T细胞介导的病理- 依赖的态度。这项拟议的研究具有创新性和重要意义，因为它侧重于TCAH如何 改变分化过程中产生的液体DNA甲基化模式，这将导致新的发现 可能导致三氯乙烯引起人类免疫紊乱的基因或甲基化模式。是这样的 知识可以通过使免疫反应正常化来识别免疫介导的靶向治疗途径 接触三氯乙烯的个人。

PROJECT SUMMARY Studies to delineate the autoimmune-promoting effects of the environmental pollutant, trichloroethylene (TCE), have focused on functional effects in effector/memory CD4+ T cells from lupus-prone mice. Our long-term goal is to understand how TCE drives CD4 cell differentiation to promote autoimmunity and/or hypersensitivity disorders. The objectives are (i) to determine how TCE through its primary metabolite, trichloroacetaldehyde hydrate (TCAH), alters differentiation of naïve CD4 cells to effector/memory subsets important in promoting (e.g., Th1 and Th17) or suppressing autoimmunity (e.g., Th2 and TREG) in vitro and (ii) to determine pathogenicity of these subsets in vivo. CD4s will be compared in both autoimmune-prone (MRL+/+) and resistant (B6) strains of mice to understand the contribution of genetic susceptibility factors. Inclusion of both sexes may reveal why being female elevates autoimmune disease risk. The central hypothesis is that TCAH promotes the differentiation of pathogenic effector cells and/or decreases expansion of effector cells associated with suppression of autoimmunity involving changes in gene expression and DNA methylation. TCAH will generate unique genetic signatures although immune pathology will be observed in MRL+/+ mice rather than in B6 mice, that will be more robust in females vs. males. The rationale is that it is now apparent that key CD4 functional effects that may be regulated at the level of DNA methylation occur during differentiation, and thus cannot be studied in already differentiated cells. The central hypothesis will be tested in three specific aims: 1) Define effects of TCAH on CD4+ T cell differentiation by assessing gene expression and 2) DNA methylation and 3) Determine pathogenicity of differentiating Th subsets in vivo. Under the first Aim, RNA-Seq will determine whether TCAH directly alters the expression of genes that may confer a selective advantage to pathogenic effector CD4+ T cells. In Aim 2, reduced representation bisulfite sequencing will be used to determine TCAH-induced changes in DNA methylation in differentiating CD4+ T cells. Experiments will test whether gene expression changes induced by TCAH are mediated at the level of DNA methylation using either methyl donors or methylation inhibitors to reverse effects. The presence of important methyl variants will be determined by flow cytometry. The third Aim will test Th subsets for their ability to generate immune pathology in adoptive transfer experiments. Treatment of cells with methyl donors prior to transfer will connect Aim 1 and 2 results to determine whether TCAH promotes T cell-mediated pathology in a DNA methylation- dependent manner. The proposed research is innovative and significant because it focuses on how TCAH alters the fluid DNA methylation pattern generated during differentiation that will lead to the discovery of novel gene or methylation patterns that may be responsible for TCE-induced immune disorders in humans. Such knowledge may identify immune-mediated pathways for targeted therapy by normalizing immune responses in TCE-exposed individuals.