人类环境或职业暴露于三氯乙烯(TCE)与不同的肝外毒性作用有关,包括肾毒性和神经毒性。通过谷胱甘肽(GSH)缀合途径的TCE的生物激活已被提出作为潜在机制,尽管只有很少的机械研究使用人类起源的细胞模型。在这项研究中,评估了六种人源细胞模型作为代表TCE缀合物的潜在靶组织的体外模型:RPTEC/TERT1(肾),HepaRG(肝脏),HUVEC/TERT2(血管内皮),LUHMES(神经元,多巴胺能),人诱导多能干细胞(hiPSC)衍生的外周神经元(UKN5)和hiPSC衍生的分化的大脑皮层培养物含有神经元和星形胶质细胞的所有亚型(BCC42)。高通量转录组筛选,利用mRNA模板寡核苷酸测序(TempO-Seq),用于研究暴露于TCE-缀合物后的转录组效应。细胞暴露于广泛浓度的S-(1,2-反式二氯乙烯基)谷胱甘肽(1,2-DCVG),S-(1,2-反式-二氯乙烯基)-L-半胱氨酸(1,2-DCVC),S-(2,2-二氯乙烯基)谷胱甘肽(2,2-DCVG),和S-(2,2-二氯乙烯基)-L-半胱氨酸(2,2-DCVC)。1,2-DCVC在所有测试模型中引起属于Nrf2途径的应激反应和未折叠蛋白反应,但程度不同。肾脏模型是对1,2-DCVC和1,2-DCVG最敏感的模型,具有3µM的早期Nrf2反应和数百个在较高浓度下的差异表达基因。暴露于2,2-DCVG和2,2-DCVC也导致RPTEC/TERT1中Nrf2途径基因上调,尽管浓度较高。在三个神经元模型中,LUHMES和BCC42均显示出显着的Nrf2反应,并且在较高浓度的UPR反应中,支持最近的假设,即1,2-DCVC可能参与TCE的神经毒性作用。γ-谷氨酰转移酶(GGT)酶表达最高的细胞模型,显示对1,2-DCVG和1,2-DCVC的细胞反应。在来自1,2-DCVG暴露的神经元模型中,由于它们的低GGT-表达,几乎没有发现影响。这项研究扩展了我们对TCES缀合物的组织特异性的了解,并强调了人类细胞模型以及转录组学在此类机理研究中的价值。
Environmental or occupational exposure of humans to trichloroethylene (TCE) has been associated with different extrahepatic toxic effects, including nephrotoxicity and neurotoxicity. Bioactivation of TCE via the glutathione (GSH) conjugation pathway has been proposed as underlying mechanism, although only few mechanistic studies have used cell models of human origin. In this study, six human derived cell models were evaluated as in vitro models representing potential target tissues of TCE-conjugates: RPTEC/TERT1 (kidney), HepaRG (liver), HUVEC/TERT2 (vascular endothelial), LUHMES (neuronal, dopaminergic), human induced pluripotent stem cells (hiPSC) derived peripheral neurons (UKN5) and hiPSC-derived differentiated brain cortical cultures containing all subtypes of neurons and astrocytes (BCC42). A high throughput transcriptomic screening, utilizing mRNA templated oligo-sequencing (TempO-Seq), was used to study transcriptomic effects after exposure to TCE-conjugates. Cells were exposed to a wide range of concentrations of S-(1,2-trans-dichlorovinyl)glutathione (1,2-DCVG), S-(1,2-trans-dichlorovinyl)-L-cysteine (1,2-DCVC), S-(2,2-dichlorovinyl)glutathione (2,2-DCVG), and S-(2,2-dichlorovinyl)-L-cysteine (2,2-DCVC). 1,2-DCVC caused stress responses belonging to the Nrf2 pathway and Unfolded protein response in all the tested models but to different extents. The renal model was the most sensitive model to both 1,2-DCVC and 1,2-DCVG, with an early Nrf2-response at 3 µM and hundreds of differentially expressed genes at higher concentrations. Exposure to 2,2-DCVG and 2,2-DCVC also resulted in the upregulation of Nrf2 pathway genes in RPTEC/TERT1 although at higher concentrations. Of the three neuronal models, both the LUHMES and BCC42 showed significant Nrf2-responses and at higher concentration UPR-responses, supporting recent hypotheses that 1,2-DCVC may be involved in neurotoxic effects of TCE. The cell models with the highest expression of γ-glutamyltransferase (GGT) enzymes, showed cellular responses to both 1,2-DCVG and 1,2-DCVC. Little to no effects were found in the neuronal models from 1,2-DCVG exposure due to their low GGT-expression. This study expands our knowledge on tissue specificity of TCE S-conjugates and emphasizes the value of human cell models together with transcriptomics for such mechanistic studies.