Interaction of the metal chelator 2,3-dimercapto-1-propanesulfonate with the rabbit multispecific organic anion transporter 1 (rbOAT1)
Interaction of the metal chelator 2,3-dimercapto-1-propanesulfonate with the rabbit multispecific organic anion transporter 1 (rbOAT1)
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DOI：
10.1124/mol.62.5.1128
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发表时间：
2002-11-01
影响因子：
3.6
通讯作者：
Wright, SH
中科院分区：
文献类型：
--
作者：
Bahn, A;Knabe, M;Wright, SH
金属螯合剂DMPS（2，3-二巯基-1-丙磺酸盐）用于治疗重金属中毒，因为它增加了这些毒素的肾脏排泄，这些毒素积累在近端小管细胞中。为了评估参与的有机阴离子转运蛋白1（OAT 1）在DMPS的肾流量，我们研究了DMPS的作用，运输介导的兔直系同源物的OAT 1，并比较这些特性与观察到的完整的分离的兔近端小管。兔OAT 1（rbOAT 1）cDNA由2124个碱基对组成，编码551个氨基酸。COS-7细胞中的异源表达揭示了rbOAT 1介导的对氨基马尿酸（PAH; K-t = 16 μ M）转运。浓度为1 mM的未标记PAH、α-酮戊二酸、尿酸盐或丙磺舒可抑制70 - 90%的[H-3] PAH摄取。使用几种克雷布斯循环中间体的顺式抑制和反式刺激实验表明α-酮戊二酸是主要的细胞内交换阴离子。还原DMPS抑制rbOAT 1介导的荧光素转运，表观Ki为102 μ M。这些特征与在离体兔近端小管中观察到的特征一致。PAH被转运到非灌注的单个近端小管S-2段，K-t为76 μ M。DMPS以71 μ M的Ki-app抑制FL摄取进入单个小管节段。1 mM PAH和1 mM DMPS反式刺激了来自预载小管的黄绿素流出，这与rbOAT 1使DMPS进入小管细胞一致。总之，rbOAT 1介导DMPS的基底外侧摄取进入近端小管细胞，这一过程涉及肾脏中重金属的解毒过程。
The metal chelator DMPS (2,3-dimercapto-1-propanesulfonate) is used to treat heavy metal intoxication because it increases renal excretion of these toxins, which are accumulated in proximal tubule cells. To evaluate the involvement of the organic anion transporter 1 (OAT1) in the renal flux of DMPS, we examined the effect of DMPS on transport mediated by the rabbit ortholog of OAT1 and compared these characteristics with those observed in intact isolated rabbit proximal tubules. The rabbit OAT1 (rbOAT1) cDNA consisted of 2124 base pairs encoding a protein of 551 amino acids. Heterologous expression in COS-7 cells revealed rbOAT1-mediated transport of p-aminohippurate (PAH; K-t = 16 muM). A 1 mM concentration of unlabeled PAH, alpha-ketoglutarate, urate, or probenecid inhibited [H-3] PAH uptake by 70 to 90%. cis-Inhibition and trans-stimulation experiments using several Krebs cycle intermediates implicated alpha-ketoglutarate as the main intracellular exchange anion. Reduced DMPS inhibited rbOAT1-mediated fluorescein transport with an apparent K-i of 102 muM. These characteristics paralleled those observed in isolated rabbit proximal tubules. PAH was transported into nonperfused single proximal tubule S-2 segments with a K-t of 76 muM. DMPS inhibited FL uptake into single tubule segments with a Ki-app of 71 muM. Fluorescein efflux from preloaded tubules was trans-stimulated by 1 mM PAH and 1 mM DMPS, consistent with DMPS entry into tubule cells by rbOAT1. In summary, rbOAT1 mediates basolateral uptake of DMPS into proximal tubule cells, implicating this process in the detoxification process of heavy metals in the kidneys.