Determining the Role of Atrazine and Atrazine-Induced Estrogen in Increasing CD4+

描述（由申请人提供）：阿特拉津是美国最广泛使用的除草剂之一。由于农作物施用后的农业径流，它是美国最常见的地下水污染物（：//water.usgs.gov/nawqa/）。阿特拉津被归类为内分泌干扰化合物，由于其诱导CYP 19（芳香酶），其催化活性导致雌激素产生增加。虽然已经进行了大量的研究，探讨与阿特拉津接触相关的潜在健康风险，但大多数研究都集中在与雌激素升高相关的生殖异常上。少数研究已经检查了阿特拉津对哺乳动物免疫系统的影响，但对免疫系统的影响在很大程度上仍然未知。以前的研究都没有集中在免疫细胞的一个关键子集，CD 4 + T辅助细胞的激活和功能。这些细胞有助于形成对病原体和癌症的保护性免疫反应，以及保持自我耐受性。CD 4 + T细胞数量或效应子活性的扰动可能对个体的健康产生可怕的后果。例如，调节性T细胞（Treg）的增加可导致免疫抑制并导致对感染或癌症的易感性增加。在初步的体外研究中，观察到阿特拉津暴露显著抑制常规T细胞的增殖、活化和细胞因子产生。此外，暴露于阿特拉津的细胞中Foxp 3 + Treg的频率显著增加。在这个提议中，我们将研究阿特拉津介导的抑制CD 4 + T细胞的机制。该提议的假设是阿特拉津增加雌激素水平，其通过直接抑制这些细胞和通过诱导Treg细胞的显著增加来抑制CD 4 + T细胞活化。将使用2个特定目标进行测试：在第一个目标中，将在体外和体内检查阿特拉津诱导Treg频率的机制。使用来自Foxp 3gfp + OT-II小鼠的TCR转基因T细胞，我们将确定阿特拉津是否诱导nTreg的扩增或常规T细胞向诱导Treg（iTreg）细胞的转化。我们还将研究阿特拉津暴露对常规T细胞表型在Treg的情况下的直接影响。在第二个目标中，使用药理学抑制剂和抗体阻断的组合，将检查阿特拉津介导的雌激素产生对Treg增加的作用。

DESCRIPTION (provided by applicant): Atrazine is one of the most widely used herbicide in the United States. As a result of agricultural runoff after crop applications, it is the most commo ground water contaminant in the US (://water.usgs.gov/nawqa/). Atrazine is classified as an Endocrine-Disrupting Compound due its induction of CYP19 (aromatase), whose catalytic activity leads to increased estrogen production. While a significant amount of research has been done looking into the potential health risks associated with atrazine exposure, most have focused on reproduction abnormalities related to elevated estrogen. A small number of studies have examined the effect of atrazine on the mammalian immune system, but the effects on the immune system remain largely unknown. None of the previous studies have focused on the activation and functions of a critical subset of immune cells, the CD4+ T helper cells. These cells help shape the protective immune response to pathogens and cancer as well as maintaining tolerance of self. Perturbations of CD4+ T cell numbers or effector activity can have dire consequences for the health of the individual. For example, an increase in regulatory T cells (Treg), can lead to immune suppression and resulting in increased susceptibility to infection or cancer. In preliminary in vitro studies, it was observed that atrazine exposure significantly inhibits the proliferation, activation and cytokine production by conventional T cells. Further, there is a significant increase in the frequency of Foxp3+ Treg in atrazine-exposed cells. In this proposal we will examine the mechanism of atrazine-mediated inhibition of CD4+ T cells. The hypothesis of this proposal is that atrazine increases estrogen levels which suppresses CD4+ T cell activation by both directly inhibiting these cells and by inducing a significant increase of Treg cells. It will be tested using 2 specific aims: In the first aim, the mechanism of atrazine-induced Treg frequency will be examined in vitro and in vivo. Using TCR transgenic T cells from Foxp3gfp+ OT-II mice, we will determine whether atrazine is inducing expansion of nTreg or conversion of conventional T cells to induced Treg (iTreg) cells. We will also examine the direct effects of atrazine exposure on the phenotype of conventional T cells in the absence of Treg. In the second aim, using a combination of pharmacological inhibitors and antibody blockade, the role of atrazine-mediated estrogen production on the Treg increase will be examined.