Determining how trichloroethylene alters CD4+ T cell function

描述（由申请人提供）：长期暴露于浓度过低而不会引起急性毒性的常见水污染物三氯乙烯（TCE），仍会促进过敏性疾病和自身免疫性疾病。我们已经证明，饮用水中的TCE诱导小鼠T细胞介导的自身免疫性肝炎。我们还发现，TCE减少活化诱导的CD 4 + T细胞凋亡，这是一个旨在防止自身免疫的过程，并刺激Th 1和Th 17细胞的产生。CD 4 + T细胞活化诱导的细胞凋亡的普遍减少可能使个体易患不同类型的免疫相关疾病。因此，证明一种常见的水污染物可以引起这种影响并描述其机制可能对人类健康具有重要意义。最近，我们发现TCE增加了一种称为MMP-7的脱落酶和一种称为骨桥蛋白的促炎细胞因子的产生。该提案将使用MRL+/+小鼠模型来检验TCE刺激巨噬细胞/树突状细胞产生MMP-7和CD 4 + T细胞产生OPN的假设，以及这两种介质共同作用以抑制CD 4 + T细胞凋亡并促进Th 1和Th 17细胞的发育。它还将检验次要假设，即由于其对CD 4 + T细胞凋亡的普遍作用，TCE的自身免疫促进作用包括自身免疫性肝炎以外的其他疾病。这些假设将在以下目标中进行检验：目标1。测试TCE如何改变CD 4 + T细胞亚群发育和巨噬细胞/树突状细胞活性。将测试来自TCE处理的MRL+/+小鼠的巨噬细胞和树突状细胞的MMP-7以及产生Th 1和Th 17细胞的细胞因子的产生。将测试TCE扩增分泌OPN以及Th 1或Th 17样细胞因子的活化（CD 44 hi）CD 4 + T细胞的能力。目标二。测试TCE如何抑制CD 4 + T细胞中活化诱导的凋亡。这一目标将通过测试外源性MMP-7和OPN抑制来自未治疗小鼠的CD 4 + T细胞中活化诱导的细胞凋亡的能力来提供“概念验证”。相互实验将使用MMP-7和/或OPN的抗体在体外阻断TCE诱导的对CD 4 + T细胞中活化诱导的细胞凋亡的阻断。目标3。利用抗原特异性CD 4 + T细胞来表征TCE在体内的作用。转基因小鼠将用于更直接地证明TCE对体内CD 4 + T细胞凋亡和效应器功能的影响，并测试TCE的自身免疫促进作用是否包括自身免疫性肝炎以外的其他疾病。 公共卫生相关性：CD 4 + T细胞活化诱导的细胞凋亡的普遍减少可能使个体易患许多不同类型的超敏性疾病和自身免疫性疾病。因此，证明一种常见的水污染物，如三氯乙烯，可以引起这种影响，并描述其机制，可能对人类健康有重要意义。

DESCRIPTION (provided by applicant): Chronic exposure to the common water pollutant trichloroethylene (TCE) at concentrations too low to cause acute toxicity can still promote hypersensitivity disorders and autoimmune disease. We have shown that TCE in drinking water induced T cell-mediated autoimmune hepatitis in mice. We also found that TCE decreased activation-induced apoptosis in CD4+ T cells, a process designed to protect against autoimmunity, and stimulates generation of both Th1 and Th17 cells. A generalized decrease in CD4+ T cell activation-induced apoptosis could predispose an individual to different types of immune-related disorders. Thus, demonstrating that a common water pollutant can cause this effect and describing the mechanism for it could have important implications for human health. Most recently we have shown that TCE increased the production of a sheddase known as MMP-7 and a pro-inflammatory cytokine known as osteopontin. This proposal will use the MRL+/+ mouse model to test the hypothesis that TCE stimulates macrophage/dendritic cell production of MMP-7 and CD4+ T cell production of OPN, and that these two mediators work together to inhibit CD4+ T cell apoptosis and promote development of Th1 and Th17 cells. It will also test the secondary hypothesis that due to its generalized effect on CD4+ T cell apoptosis the autoimmune-promoting effects of TCE encompasses other diseases besides autoimmune hepatitis. These hypotheses will be tested in the following Aims: Aim 1. Test how TCE alters CD4+ T cell subset development and macrophage/dendritic cell activity. Macrophages and dendritic cells from TCE-treated MRL+/+ mice will be tested for production of MMP-7, as well as cytokines that generate Th1 and Th17 cells. The ability of TCE to expand activated (CD44hi) CD4+ T cells that secrete OPN as well as Th1- or Th17-like cytokines will be tested. Aim 2. Test how TCE inhibits activation-induced apoptosis in CD4+ T cells. This aim will provide "proof of concept" by testing the ability of exogenous MMP-7 and OPN to inhibit activation-induced apoptosis in CD4+ T cells from untreated mice. Reciprocal experiments will use antibodies for MMP-7 and/or OPN to block TCE-induced blockade of activation-induced apoptosis in CD4+ T cells in vitro. Aim 3. Using antigen-specific CD4+ T cell to characterize the effects of TCE in vivo. Transgenic mice will be used to more directly demonstrate the effects of TCE on CD4+ T cell apoptosis and effector function in vivo, and to test whether the autoimmune-promoting effects of TCE encompasses other diseases besides autoimmune hepatitis. PUBLIC HEALTH RELEVANCE: A generalized decrease in CD4+ T cell activation-induced apoptosis could predispose an individual to many different types of hypersensitivity disorders and autoimmune disease. Consequently, demonstrating that a common water pollutant such as trichloroethylene can cause this effect and describing the mechanism for it could have important implications for human health.