Perchloroethylene Exposure and Autoimmunity

描述（由申请人提供）：四氯乙烯（四氯乙烯; PCE）是一种广泛使用的干洗剂、织物整理剂和金属去污剂。许多人在职业上或通过环境接触到这种化学品。除了其器官毒性外，PCE暴露还涉及诱导自身免疫和/或自身免疫性疾病（AD），如高水平的抗核抗体、皮疹、硬皮病和系统性红斑狼疮（SLE）样症状所示。该提案的重点是确定PCE暴露诱导/加剧自身免疫反应，并阐明这种反应的假定机制。我们假设PCE可以通过两种可能的机制诱导自身免疫应答：1）通过PCE代谢，其中代谢物加合蛋白可以充当新抗原，和/或2）通过脂质过氧化（LPO），其中LPO衍生的反应性醛（LPDA）如4-羟基壬烯醛（HNE）和丙二醛（MDA）可以形成LPDA-蛋白加合物并引发自身免疫应答。通过这些机制中的任一种产生新抗原可以引发针对这种新抗原的抗体的产生。预期这些抗体表现出不同的特异性，特别是针对PCE代谢物或LPDA结合的细胞大分子和共享共同表位的那些大分子。抗体与这些大分子的结合将对组织和/或器官有害，并最终导致AD。使用雌性MRL +/+和NZB/WF 1小鼠（自身免疫易感）和B6 C3 F1小鼠（非自身免疫性），PCE诱导和/或加重AD的潜力将通过测定血清中的自身免疫标志物[抗核（ANA）-、抗单链DNA（抗ssDNA）-，抗双链DNA（抗dsDNA）-、抗心磷脂-和抗Scl 70-抗体，和循环免疫复合物]，以及组织的形态学评估，特别是肾脏（肾小球肾炎、血管炎和免疫复合物沉积）和皮肤（血管周围浸润、真皮小动脉和毛细血管壁增厚）。我们还将评估先天性免疫应答在PCE诱导的自身免疫进展中的作用（目的1）。此外，为了阐明PCE诱导的自身免疫的机制并支持我们的假设，我们将使用蛋白质组学方法在PCE处理的小鼠的组织和/或血清中表征三氯酰化蛋白加合物和LPDA-蛋白加合物，以定量和评价其自身免疫潜力。三氯酰化蛋白加合物和LPDA-蛋白加合物的抗体也将分析与自身免疫标志物的相关性（目的2）。这些研究将确定PCE诱导和/或加速自身免疫反应，并且还将提供PCE暴露、加合蛋白和自身免疫之间的联系。这些研究最终将有助于设计策略，以预防或减少因接触PCE或相关环境/职业制剂而导致的AD。

DESCRIPTION (provided by applicant): Tetrachloroethylene (perchloroethylene; PCE) is a widely used dry-cleaning, fabric-finishing and metal degreasing agent. Large number of humans are exposed to this chemical either occupationally or through the environment. Besides its organ toxicity, PCE exposure has been implicated in inducing autoimmunity and/or autoimmune diseases (ADs), as evident from high levels of anti-nuclear antibodies, rashes, scleroderma and systemic lupus erythematosus (SLE)-like symptoms. The focus of this proposal is to establish that PCE exposure induces/exacerbates an autoimmune response and to elucidate the putative mechanism(s) of such response. We hypothesize that PCE can induce an autoimmune response through two possible mechanisms: 1) via PCE metabolism where metabolite-adducted proteins can act as neoantigens, and/or 2) via lipid peroxidation (LPO) where LPO-derived reactive aldehydes (LPDAs) such as 4-hydroxynonenal (HNE) and malondialdehyde (MDA) can form LPDA-protein adducts and elicit an autoimmune response. Generation of neoantigen(s) via either of these mechanisms can elicit the production of antibodies against such neoantigen(s). These antibodies are expected to exhibit diverse specificities, particularly towards cellular macromolecule(s) to which PCE metabolites or LPDAs are bound and those macromolecules which share common epitopes. The binding of antibodies to these macromolecules would be detrimental to tissues and/or organs and eventually lead to ADs. Using female MRL +/+ and NZB/WF1 mice (autoimmune-prone) and B6C3F1 mice (non-autoimmune), the potential of PCE in inducing and/or exacerbating ADs will be evaluated by determining the markers of autoimmunity in the serum [anti-nuclear (ANA)-, anti-single stranded DNA (anti- ssDNA)-, anti-double stranded DNA (anti-dsDNA)-, anti-cardiolipin- and anti-Scl70-antibodies, and circulating immune complexes], and morphological assessment of tissues, especially kidneys (glomerulonephritis, vasculitis and deposition of immune complexes) and skin (perivascular infiltrates, thickening of the walls of dermal arterioles and capillaries). We will also evaluate te role of innate immune response in the progression to PCE-induced autoimmunity (Aim 1). Furthermore, to elucidate the mechanism(s) of PCE-induced autoimmunity and support our hypothesis, we will characterize trichloroacylated-protein adducts and LPDA- protein adducts using proteomic approaches in the tissues and/or serum of PCE-treated mice for quantitation and evaluation of their autoimmune potential. Antibodies to trichloroacylated-protein adducts and LPDA- protein adducts will also analyze for correlation with autoimmunity markers (Aim 2). These studies will establish that PCE induces and/or accelerates an autoimmune response and will also provide a link between PCE exposure, adducted proteins and autoimmunity. These studies will eventually help in designing strategies to prevent or reduce ADs resulting from exposure to PCE or related environmental/occupational agents.