Department of Medicine/Nephrology, David Geffen School of Medicine, University of California at Los Angeles, CA 90095, USA.
Toxicol Appl Pharmacol. 2010 Apr 15;244(2):218-25. doi: 10.1016/j.taap.2009.12.035. Epub 2010 Jan 6.
N-acetyl-S-(1,2-dichlorovinyl)-l-cysteine (Ac-DCVC) and S-(1,2-dichlorovinyl)-l-cysteine (DCVC) are the glutathione conjugation pathway metabolites of a common industrial contaminant and potent nephrotoxicant trichloroethylene (TCE). Ac-DCVC and DCVC are accumulated in the renal proximal tubule where they may be secreted into the urine by an unknown apical transporter(s). In this study, we explored the hypothesis that the apical transport of Ac-DCVC and/or DCVC may be mediated by the multidrug resistance associated protein 2 (Mrp2, ABCC2), which is known to mediate proximal tubular apical ATP-dependent transport of glutathione and numerous xenobiotics and endogenous substances conjugated with glutathione. Transport experiments using membrane vesicles prepared from mouse proximal tubule derived cells expressing mouse Mrp2 utilizing ATPase assay and direct measurements of Ac-DCVC/DCVC using liquid chromatography/tandem mass-spectrometry (LC/MS/MS) demonstrated that mouse Mrp2 mediates ATP-dependent transport of Ac-DCVC. Expression of mouse Mrp2 antisense mRNA significantly inhibited the vectorial basolateral to apical transport of Ac-DCVC but not DCVC in mouse proximal tubule derived cells endogenously expressing mouse Mrp2. The results suggest that Mrp2 may be involved in the renal secretion of Ac-DCVC.
N-乙酰-S-(1,2-二氯乙烯基)-L-半胱氨酸 (Ac-DCVC) 和 S-(1,2-二氯乙烯基)-L-半胱氨酸 (DCVC) 是一种常见工业污染物和强效肾毒物三氯乙烯 (TCE) 的谷胱甘肽结合途径代谢物。Ac-DCVC 和 DCVC 在肾近端小管中积累,在那里它们可能被未知的顶端转运体 (s) 分泌到尿液中。在这项研究中,我们假设 Ac-DCVC 和/或 DCVC 的顶端转运可能由多药耐药相关蛋白 2 (Mrp2,ABCC2) 介导,已知 Mrp2 介导谷胱甘肽和许多外源物质和内源性物质与谷胱甘肽结合的近端肾小管顶端 ATP 依赖性转运。使用从表达小鼠 Mrp2 的小鼠近端肾小管衍生细胞制备的膜囊泡进行的转运实验,利用 ATPase 测定法和使用液相色谱/串联质谱法 (LC/MS/MS) 直接测量 Ac-DCVC/DCVC,证明小鼠 Mrp2 介导 Ac-DCVC 的 ATP 依赖性转运。表达小鼠 Mrp2 反义 mRNA 显著抑制了在天然表达小鼠 Mrp2 的小鼠近端肾小管衍生细胞中 Ac-DCVC 的载体基底外侧到顶端的转运,但不抑制 DCVC。结果表明,Mrp2 可能参与 Ac-DCVC 的肾分泌。