Determining how trichloroethylene alters CD4+ T cell function

描述（由申请人提供）：长期暴露于常见的水污染物三氯乙烯（TCE），浓度过低，不会引起急性毒性，但仍可促进超敏性疾病和自身免疫性疾病。我们已经证明饮用水中的TCE可诱导小鼠T细胞介导的自身免疫性肝炎。我们还发现，TCE减少了激活诱导的CD4+ T细胞凋亡，这是一个旨在保护自身免疫的过程，并刺激Th1和Th17细胞的产生。CD4+ T细胞激活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造成这种影响并描述其机制可能对人类健康产生重要影响。最近，我们发现TCE增加了一种脱落酶MMP-7和一种促炎细胞因子骨桥蛋白的产生。本课题将利用MRL+/+小鼠模型验证TCE刺激巨噬细胞/树突状细胞产生MMP-7和CD4+ T细胞产生OPN的假设，这两种介质共同抑制CD4+ T细胞凋亡，促进Th1和Th17细胞的发育。这也将检验第二个假设，即由于其对CD4+ T细胞凋亡的普遍作用，TCE的自身免疫促进作用除自身免疫性肝炎外还包括其他疾病。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CD4+ T细胞亚群发育和巨噬细胞/树突状细胞活性。tce处理的MRL+/+小鼠的巨噬细胞和树突状细胞将被测试产生MMP-7，以及产生Th1和Th17细胞的细胞因子。TCE扩大分泌OPN以及Th1或th17样细胞因子的活化（CD44hi） CD4+ T细胞的能力将被测试。目标2。检测TCE对CD4+ T细胞活化诱导凋亡的抑制作用。通过测试外源性MMP-7和OPN抑制未处理小鼠CD4+ T细胞活化诱导的凋亡的能力，该目标将提供“概念证明”。在体外实验中，将使用MMP-7和/或OPN抗体来阻断tce诱导的CD4+ T细胞活化诱导凋亡的阻断。目标3。使用抗原特异性CD4+ T细胞在体内表征TCE的作用。转基因小鼠将在体内更直接地证明TCE对CD4+ T细胞凋亡的影响和效应物功能，并检验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。

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.