药物转运体OAT2研究进展

有机阴离子转运体2(OAT2)属于有机阴离子转运体家族成员,主要分布于肝肾,介导肌酐、尿酸等内源性物质及多种外源性药物的跨膜转运。OAT2对外源性物质如药物的体内过程如吸收、分布、代谢和排泄过程起着重要作用。研究表明OAT2的表达与活性被药物、疾病、性别及基因多态性等多种因素影响,亦受到核受体等信号通路调控。故本文综述药物转运体OAT2的结构与分布、底物、调控机制、临床意义的研究进展,为OAT2可能介导药物相互作用及药物疗效预测提供参考。     

肾脏OAT1/3蛋白介导的玉屏风抗炎免疫药效配伍增效的药动学机制

目的本研究通过整体动物、细胞模型水平分别考察复方玉屏风(YPF)、各单味药黄芪、白术、防风以及部分有效成分对肾组织、细胞有机阴离子转运蛋白(OAT)蛋白及mRNA表达的影响,探讨YPF配伍后抗炎免疫药效增强的药动学分子机制及其与肾脏OAT1/3蛋白表达、活性的相关性。方法整体动物实验:大鼠随机分为生理盐水组、YPF组、黄芪组、白术组、防风组,灌胃连续给药21天。第21 d收集各组肾组织,Western印迹法及RT-PCR法检测肾组织中OAT1/3蛋白及mRNA的表达。细胞实验:培养人胚胎肾细胞HEK-293,采用MTT法确定YPF组、黄芪组、白术组、防风组及单一活性成分升麻苷组、5-O-甲基维斯阿米醇苷组、白术内酯Ⅰ组、白术内酯Ⅲ组的给药浓度,并以该浓度刺激细胞,应用Western印迹法及RTPCR法检测各给药组细胞的OAT1/3蛋白及mRNA表达变化。结果 YPF、防风水煎剂均能不同程度降低大鼠肾脏、HEK-293细胞中的OAT1/3蛋白及mRNA表达水平。白术水煎液降低了大鼠肾脏、HEK-293细胞的OAT1蛋白及mRNA的表达水平,但升高了OAT3蛋白及mRNA的表达水平;白术内酯Ⅰ(30 g·L~(-1))、升麻苷(30 g·L~(-1))、5-O-甲基维斯阿米醇苷(50 g·L~(-1))能显著降低HEK-293细胞中的OAT1/3蛋白及mRNA表达水平。白术内酯Ⅲ(30 g·L~(-1))降低了HEK-293细胞中OAT1蛋白及mRNA的表达,但明显升高OAT3蛋白及mRNA的表达水平。结论相较于黄芪,YPF、防风水煎剂和部分有效成分如升麻苷等,可明显抑制肾OAT1和OAT3 mRNA和蛋白的表达,进而抑制其底物的肾排泄,延长药物的体内作用时间,这可能即是YPF配伍增效的药动学机制之一。     

有机阴离子转运多肽介导的药物相互作用研究进展

药物转运体介导的药物相互作用正日益受到人们的关注和重视,近年来的研究表明药物转运体对药物的吸收、分布和排出有着重要的作用。有机阴离子转运多肽是一类药物摄取转运体,其表达分布广泛,转运的内源性和外源性的底物众多,一些药物因抑制有机阴离子转运体而导致药物相互作用。本文综述了有机阴离子转运多肽家族不同成员的组织分布、结构特点以及其介导的药物相互作用的最新研究进展。     

小檗碱对有机阴离子转运体抑制作用及双向跨膜转运研究

目的 研究小檗碱对有机阴离子转运体（OATs）的抑制作用及其双向跨膜转运情况。方法 应用由转染试剂Lipo 3 000介导的动物细胞转基因方法、经筛选得到人有机阴离子转运体OAT1、OAT2、OAT3、OAT4、OAT7和URAT1高表达单克隆细胞株;以野生型（WT）细胞为对照组,用各转运体放射性同位素标记底物和抑制剂验证其转运活性;观察100 μmol/L小檗碱对各转运体的抑制作用,并测定小檗碱对URAT1转运活性的半数抑制浓度（IC₅₀）。通过Caco-2细胞模型研究小檗碱的双向跨膜转运情况。结果 100 μmol/L小檗碱使OAT1、OAT2、OAT3、OAT4、OAT7和URAT1相对转运活性分别下降至（70.48±4.23）%、（69.13±1.28）%、（72.12±3.28）%、（79.77±6.49）%、（69.51±5.99）%、（38.4±2.67）%;小檗碱对URAT1抑制作用的IC₅₀为13.6 μmol/L;在50和100 μmol/L浓度下,小檗碱在顶侧（AP侧）-基底侧（BL侧）方向的跨膜渗透率P_app（A-B）分别为0.28×10^-6 cm/s和0.40×10^-6 cm/s,其相对应的外排率分别为3.18和3.15。结论 小檗碱对URAT1的抑制作用较强,对OAT1、OAT2、OAT3、OAT4、OAT7抑制作用相对较弱,小檗碱是一些外排蛋白的底物,为预测小檗碱可能发生的药物-药物相互作用、解释生物利用度低提供了理论依据。     

肾脏转运体介导抗病毒药物肾排泄的研究进展

目的:了解肾脏转运体介导抗病毒药物肾排泄的研究现状,为临床合理用药提供参考.方法:对近年抗病毒药物与肾脏转运体相关的文献进行综述.结果:有机阴离子转运体(Organic Anion Transporters,OAT1～3)和有机阳离子转运体(Organic Cation Transporters,OCT1～3)介导药物流入细胞内,而ATP结合转运体(ATP Binding Cassette,P-gp,MRP2～5)介导药物从细胞排出.寡肽转运体(Peptide Transporters,PEPT1～2)介导伐昔洛韦双向扩散.结论:通过介导药物的摄取和排出,肾脏转运体在调节体内常用抗病毒药物浓度时发挥重要的作用.     

有机阴离子转运多肽1A2对药物转运的影响

有机阴离子转运多肽1A2（OATP1A2）是人体内重要的膜转运蛋白,在肝、肾、小肠、血脑屏障等组织部位进行表达,介导内、外源物质的跨细胞转运,对药物的吸收、分布和消除起着十分重要的作用。本文将对OATP1A2的组织分布和基本功能、基因多态性及其对药物转运的影响作一综述。     

植物药-化学药间基于有机阴离子转运多肽介导的相互作用研究进展

有机阴离子转运多肽(OATPs)是人及动物体内最重要的细胞膜吸收转运蛋白,在肝脏中有大量分布,介导多种内源性物质及临床常用药物的吸收转运,影响着药物在体内的吸收、分布和清除过程.许多植物药及其有效成分是OATPs的底物,它们对OATPs活性表现出抑制或者诱导作用,从而对OATPs介导的其他药物转运产生影响,改变药物生物利用度或产生不良反应.本文概述了基于OATPs介导的植物药-化学药物之间可能发生的相互作用研究进展.     

有机阴离子转运蛋白在外源化学物毒性中的作用

机体接触各种潜在毒性有机阴离子,包括内源性物质如激素、神经递质和细胞代谢产物;外源性化学物质如多种药物、农药和动植物毒素等。快速有效地清除其中的毒性物质是机体最好的防御方式。有机阴离子转运蛋白介导的跨上皮主动转运通常是其中的限速过程。因此,研究有机阴离子转运蛋白的种类、分布及其转运与表达调控机制具有重要的毒理学意义。     

茶多酚对高尿酸血症小鼠尿酸产生与排泄的影响及机制研究

目的观察茶多酚(green tea polyphenols,GTP)对氧嗪酸钾(PO)诱导的高尿酸血症(HUA)小鼠血尿酸水平的影响,并从调节尿酸产生和排泄途径探讨其药理机制。方法每天分别灌胃给予PO(250 mg·kg~(-1))和GTP(150、300、600mg·kg~(-1)),连续7 d。磷钨酸法检测小鼠血尿酸水平,比色法和Western blot法分别检测肝脏黄嘌呤氧化酶(XOD)活性与表达,免疫组织化学染色法检测肾脏中尿酸盐转运子1(URAT1)、有机阴离子转运子(OAT)1和3的表达。结果GTP明显降低了氧嗪酸钾诱导的HUA小鼠血尿酸水平(P<0.05或P<0.01);同时,GTP明显降低了HUA小鼠肝脏XOD的活性和表达(P<0.05或P<0.01);此外,GTP还明显降低了HUA小鼠肾脏URAT1的表达,增强了OAT1和OAT3的表达(P<0.05或P<0.01)。结论 GTP对PO诱导的HUA小鼠血尿酸水平有明显降低作用,其机制与减少尿酸产生和增加尿酸排泄密切相关。     

有机阴离子转运多肽及其对药物吸收、分布和排出的影响

药物在体内的转运正日益被认为是影响药效和药物残留的关键因素.近年来研究表明位于细胞膜上的转运蛋白在药物的吸收、分布和排出中发挥重要作用,药物在组织间的定向运动依赖于药物吸收和排出转运蛋白的协同作用.有机阴离子转运多肽(OATP)是一类药物吸收转运蛋白,在药物吸收、组织分布及其在肝、肾的清除中起重要作用.本文就近年来对OATP结构特点、生物学功能的研究进行综述.     

Benzylpenicillin inhibits the renal excretion of acyclovir by OAT1 and OAT3

BackgroundAcyclovir is acyclic guanosine derivative. Benzylpenicillin (PCG) is a β-lactam antibiotic. The purpose of this study was to investigate the pharmacokinetic drug-drug interaction (DDI) between PCG and acyclovir.MethodWhen acyclovir and PCG were co-administered, plasma concentration of acyclovir, urinary excretion of acyclovir in vivo, uptake of acyclovir in kidney slices and uptake of acyclovir in human (h) OAT1/hOAT3- HEK293 cells were determined to examine the effect of PCG on urinary excretion of acyclovir.ResultsThe plasma concentration of acyclovir was increased markedly and accumulative renal excretion and renal clearance of acyclovir were decreased significantly after intravenous administration of acyclovir in combination with PCG. PCG could decrease the uptake of acyclovir in kidney slices and in hOAT1-/hOAT3-human embryonic kidney (HEK293) cells.ConclusionsIt indicates that acyclovir is a substrate for OAT1 and OAT3. PCG inhibits the renal excretion of acyclovir by inhibiting renal transporters OAT1 and OAT3 in vivo and in vitro. These results suggest important information for DDI between PCG and acyclovir in kidney.     

Pharmacogenomics of the OATP and OAT families

Drug disposition is highly dependent on the interplay between drug metabolism and transport in organs such as the intestine, kidney, and liver. Genetically determined variation in drug transporter function or expression is now increasingly recognized to have a significant role as a determinant of intersubject variability in drug response. Similar to the discoveries of functional genetic variations in drug efflux transporters, such as multi-drug resistance proteins 1 and 2, there have been considerable advances in the identification of single nucleotide polymorphisms in transporters that facilitate cellular drug uptake. Among the uptake transporters, members of the organic anion-transporting polypeptides and organic anion transporters can mediate the cellular uptake of a large number of structurally divergent compounds. Accordingly, functionally relevant polymorphisms in these transporters may contribute to interindividual and interethnic variability in drug disposition and response. In this review, recent progress relating to pharmacogenomics of organic anion transporters will be outlined along with a compilation of currently known genetic polymorphisms.     

MDR1 and OAT1/OAT3 Mediate the Drug-Drug Interaction between Puerarin and Methotrexate

Purpose

To conduct in vivo and in vitro experiments to investigate puerarin (PUR), an isoflavone C-glyoside, and elucidate its ability to alter methotrexate (MTX) transport and pharmacokinetics.

Methods

In vivo absorption studies, in vitro everted intestinal sac preparation, kidney slices in rats and bi-directional transport assay with mock-/MDCK-MDR1 cells, uptake studies in HEK293-OAT1/3 cells were employed to evaluate the interaction.

Results

In vivo and in vitro MTX absorption in rats were enhanced in combination with PUR. PUR inhibited digoxin efflux transport in MDCK-MDR1 monolayers with an IC₅₀ value of 1.6?±?0.3 μM, suggesting that the first target of drug interaction was MDR1 in the intestine during the absorption process. MTX renal clearance decreased significantly after simultaneous intravenous administration. MTX uptake in rat kidney slices and HEK293-OAT1/3 cells were markedly inhibited by PUR, suggesting that the second target of drug interaction was OATs located in the kidney. Moreover, concomitant administration of PUR reduced renal MTX accumulation and plasma levels of creatinine and BUN.

Conclusions

Co-administration of PUR enhanced MTX exposure by inhibition of intestinal MDR1 and renal OAT1/3. Although the renal damage of MTX was improved by PUR, the high level exposure of MTX should be cautious in the clinical usage.     

Molecular Cloning and Functional Analyses of OAT1 and OAT3 from Cynomolgus Monkey Kidney

No HeadingPurpose. The functional characterization of monkey OAT1 (SLC22A6) and OAT3 (SLC22A8) was carried out to elucidate species differences in the OAT1- and OAT3-mediated transport between monkey and human.Methods. The cDNAs of monkey OAT1 and OAT3 were isolated from monkey kidney, and their stable transfectants were established in HEK293 cells (mkOAT1- and mkOAT3-HEK). Transport studies were performed using cDNA transfectants, and kinetic parameters were compared among rat, monkey and human.Results. The amino acid sequences of mkOAT1 and mkOAT3 exhibit 97% and 96% identity to their corresponding human orthologues. For OAT1, there was no obvious species difference in the K_m values and the relative transport activities of 11 substrates with regard to p-aminohippurate transport. For OAT3, there was no species difference in the K_m values and in the relative transport activities of nine substrates with regard to benzylpenicillin transport between monkey and human. However, the relative transport activities of indoxyl sulfate, 3-carboxy-4-methyl-5-propyl-2-furanpropionate, and estrone-3-sulfate showed a difference between primates and rat and gave a poor correlation.Conclusions. These results suggest that monkey is a good predictor of the renal uptake of organic anions in the human.     

Renal organic anion transporters OAT1 and OAT3 mediate the cellular accumulation of 5-sulfooxymethylfurfural, a reactive, nephrotoxic metabolite of the Maillard product 5-hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF) is formed when sugars are acidified or heated. It is present at high levels in numerous foods. HMF is inactive in standard genotoxicity tests, but can be metabolized to a chemically reactive intermediate, 5-sulfooxymethylfurfural (SMF), which is mutagenic and carcinogenic. We recently found that direct parental administration of SMF to mice leads to abundant acute necrosis and proteinaceous casts in the proximal tubules as the dominating toxicological effect. Since proximal tubule cells actively mediate the excretion of many organic anions, we hypothesized that transporter-mediated uptake of SMF into the cells could be the reason for this selective organotoxicity. To test this hypothesis, we used human embryonic kidney (HEK293) cells stably expressing human (h) OAT1 or OAT3. SMF was a competitive inhibitor of p-aminohippurate uptake by hOAT1 and estrone sulfate uptake by hOAT3 with K_i values of 225 μM and 1.5 mM, respectively. Moreover, the initial rates of SMF uptake were 5.2- and 3.1-fold higher in cells expressing hOAT1 and hOAT3, respectively, than in control HEK293 cells. Likewise, the sensitivity of hOAT1- and hOAT3-expressing cells to SMF cytotoxicity was significantly higher than that of control cells, and was reduced by addition of probenecid, an inhibitor of OATs. Taken together, these results indicate that OAT1 and OAT3 mediate the uptake of SMF into proximal tubule cells and thereby may be involved in SMF-induced nephrotoxicity.     

Organic anion transporter 1 (OAT1) involved in renal cell transport of aristolochic acid I

Aristolochic acids (AAs) are a family of structurally related nitrophenanthrene carboxylic acids that are present in medicinal herbs such as Aristolochia species. The organic anion transporters (OATs) of the solute carrier (SLC22) gene family located in the renal proximal tubules play a key role in the excretion of a variety of exogenous and endogenous compounds. However, it is unclear how AAs permeate into renal epithelial cells. In this regard, we investigated the role of rat OAT1 ([rOAT1] SLC22A6) in the cellular uptake of AAI in vitro and in vivo. A concentration- and time-dependent intracellular accumulation of AAI was observed in rOAT1-transfected human embryonic kidney 293 (HEK293) cells, which was 2- to 6-fold higher than the control cells. There was a significantly increased rate of cellular apoptosis in rOAT1-transfected HEK293 cells than control cells after AAI treatment. Para-aminohippuric acid (PAH) significantly reduced the intracellular accumulation of AAI in rOAT1-transfected HEK293 cells. Administration of AAI for 35 days in rats caused significantly reduced expression of OAT1 in basolateral membrane and declined renal clearance of PAH as well as renal proximal tubule injuries. These findings indicate that AAI is taken up by OAT1, which then exert its intracellular toxic effects on renal proximal tubule cells, which in turn damage functional OAT1 and may further disturb the transport of its substrates.