Uptake of cardiovascular drugs into the human heart -: Expression, regulation, and function of the carnitine transporter OCTN2 (SLC22A5)
Uptake of cardiovascular drugs into the human heart -: Expression, regulation, and function of the carnitine transporter OCTN2 (SLC22A5)
复制标题
DOI：
10.1161/circulationaha.105.586107
复制
发表时间：
2006-02-28
期刊：
影响因子：
37.8
通讯作者：
Kroemer, HK
中科院分区：
文献类型：
--
作者：
Grube, M;Schwabedissen, HEUMZ;Kroemer, HK
背景-迄今为止，药物通过转运蛋白进入人体心脏的机制还知之甚少.候选蛋白质是有机阳离子转运蛋白新型2型（OCTN 2）（SLC 22 A5），生理上作为肉毒碱的钠依赖性转运蛋白。我们研究了OCTN 2在人心脏中的表达和定位，OCTN 2对药物的摄取，以及OCTN 2与消除ATP结合盒（ABC）转运蛋白ABCB 1（P-糖蛋白）的功能偶联。方法和结果-通过定量聚合酶链反应分析了心脏样本中OCTN 2和ABCB 1的信使RNA水平。OCTN 2在所有耳廓样本中表达，显示出明显的个体间变异性（每20 ng RNA 35至1352个拷贝）。尽管OCTN 2的单核苷酸多态性（启动子-207位的G/C）对表达没有影响，但β-受体阻滞剂的施用导致表达显著增加。通过原位杂交、激光显微切割和免疫荧光显微镜对OCTN 2进行定位，发现OCTN 2主要在内皮细胞中表达。对于功能研究，在Madin-Darby犬肾（MDCKII）细胞中表达OCTN 2。使用这个系统，维拉帕米，螺内酯，和米屈肼的特点是作为抑制剂（EC 50 = 25，26，和21 μ mol/L，分别）和作为底物。与OCTN 2一样，ABCB 1优先在内皮细胞中表达。在人心脏中观察到OCTN 2和ABCB 1表达的显著相关性，这表明功能偶联。因此，用双转染子测试0 CTN 2与ABCB 1的相互作用。这种方法导致维拉帕米的跨细胞转运显著增加，维拉帕米是OCTN 2和ABCB 1的底物。结论-OCTN 2在人类心脏中表达，并可通过药物给药进行调节。此外，OCTN 2可以促进心血管药物的心脏摄取。
Background - To date, the uptake of drugs into the human heart by transport proteins is poorly understood. A candidate protein is the organic cation transporter novel type 2 (OCTN2) (SLC22A5), physiologically acting as a sodium-dependent transport protein for carnitine. We investigated expression and localization of OCTN2 in the human heart, uptake of drugs by OCTN2, and functional coupling of OCTN2 with the eliminating ATP-binding cassette (ABC) transporter ABCB1 (P-glycoprotein).Methods and Results - Messenger RNA levels of OCTN2 and ABCB1 were analyzed in heart samples by quantitative polymerase chain reaction. OCTN2 was expressed in all auricular samples that showed a pronounced interindividual variability ( 35 to 1352 copies per 20 ng of RNA). Although a single-nucleotide polymorphism in OCTN2 (G/C at position - 207 of the promoter) had no influence on expression, administration of beta-blockers resulted in significantly increased expression. Localization of OCTN2 by in situ hybridization, laser microdissection, and immunofluorescence microscopy revealed expression of OCTN2 mainly in endothelial cells. For functional studies, OCTN2 was expressed in Madin-Darby canine kidney (MDCKII) cells. Using this system, verapamil, spironolactone, and mildronate were characterized both as inhibitors (EC50 = 25, 26, and 21 mu mol/L, respectively) and as substrates. Like OCTN2, ABCB1 was expressed preferentially in endothelial cells. A significant correlation of OCTN2 and ABCB1 expression in the human heart was observed, which suggests functional coupling. Therefore, the interaction of OCTN2 with ABCB1 was tested with double transfectants. This approach resulted in a significantly higher transcellular transport of verapamil, a substrate for both OCTN2 and ABCB1.Conclusions - OCTN2 is expressed in the human heart and can be modulated by drug administration. Moreover, OCTN2 can contribute to the cardiac uptake of cardiovascular drugs.