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AIM: To explore the effects of inflammatory conditions on the pharmacokinetics of methotrexate (MTX) and its related mechanisms. METHODS: The model of adjuvant induced arthritis (AIA) was established. The expression of organic anion transporter 3 (OAT3) in kidney was detected by immunohistochemistry, Western blotting and QPCR. The plasma concentration of MTX was detected by LC-MS/MS, and the pharmacokinetics of MTX after different administration time were compared by isolated rat kidney perfusion, kidney slices, in vitro cell uptake and transport experiments. RESULTS: The expression of OAT3 was significantly increased in the kidneys of AIA rats by immunohistochemistry, Western blotting and QPCR. At the same time, the concentration of MTX was detected by the optimized LC-MS/MS. The results showed that the uptake of MTX in the kidney slices of AIA rats was significantly increased, and Pro could reduce the excretion of MTX by inhibiting OAT3. Furthermore, it was demonstrated in vitro that inflammatory pathology can promote renal excretion of MTX by increasing the expression and functional activity of OAT3.CONCLUSION: Under inflammatory pathological conditions, it can increase the expression of OAT3 in the kidney, enhance its functional activity, accelerate the uptake of MTX by the kidney, and promote the excretion of MTX.
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Objective:To analyze the distribution of solute carrier organic anion transporter family member 1b1 ( SLCO1B1) and apolipoprotein E ( ApoE) genes in a population from southern Yunnan. Methods:The data of 104 patients who received treatment in Southern Central Hospital of Yunnan Province (The First People's Hospital of Honghe State) between May 2019 and June 2020 were collected. The distribution of SLCO1B1 and ApoE genes and their relationship with nationality, sex, and age were analyzed and compared between different regions. Results:The percentage of patients carrying *1a/*1a, *1a/*1b, *1b/*1b, *1a/*15, *1b/*15, five phenotypes of SLCO1B1 gene, in the population from southern Yunnan was 4.81%, 32.69%, 42.31%, 12.50% and 7.69% respectively. Phenotypes *1a/*5, *5/*5, *5/*15 and *15/*15 were not detected. Normal metabolic phenotype of SLCO1B1 accounted for 79.81%, and intermediate metabolic phenotype of SLCO1B1 accounted for 20.19%. Weak metabolic phenotype was not detected. The percentage of patients carrying E2/E2, E2/E3, E3/E3, E3/E4, E4/E4, five phenotypes of ApoE gene in the population from southern Yunnan was 0.96%, 16.35%, 70.19%, 11.54% and 0.96% respectively. E2/E4 phenotype was not detected. The percentage of patients with ApoE protective phenotype, ApoE normal phenotype, and ApoE risk phenotype was 17.31%, 70.19% and 12.50% respectively. The observed polymorphism mutation frequency of SLCO1B1 and ApoE genes was consistent with the Hardy-Weinberg equilibrium ( P > 0.05), suggesting constancy and a population representation. The Fisher test showed that SLCO1B1 gene distribution differed significantly between ethnic minorities and Han nationality in southern Yunnan ( P = 0.013). There was no significant difference in SLCO1B1 gene distribution between different sexes and between different ages (all P > 0.05). There was no significant difference in ApoE gene distribution between ethnic minorities and Han nationality, between different sexes, and between different ages in the population from southern Yunnan (all P > 0.05). Conclusion:SLCO1B1 gene distribution is related to nationality in the population from southern Yunnan, but it is unrelated to sex and age. ApoE gene distribution is unrelated to nationality, sex and age.
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Objective:To investigate the potential drug interactions of outpatient prescriptions containing metformin combined with other drugs from the perspective of drug transporters.Methods:The prescriptions containing metformin that were used in the Outpatient Department of Hainan General Hospital, China between July and December 2019 were collected. The potential interaction between drugs and metformin used in the prescriptions was analyzed according to drug instructions, Drugbank, PubMed databases.Results:A total of 15 568 outpatient prescriptions containing metformin were collected, including 9 146 prescriptions for male patients and 6 422 prescriptions for female patients. A total of 14 902 prescriptions contained combined medication. The drugs used in combination included other hypoglycemic drugs, antiplatelet drugs, antihypertensive drugs, lipid-lowering drugs, and neuroprotective drugs. The drug transporters including aspirin, atorvastatin calcium, repaglinide, bisoprolol, metoprolol and clopidogrel had a potential interaction with metformin. There were 11 614 prescriptions containing drug transporters and metformin, including 5 938 prescriptions inhibiting organic cation transporter 1 and 5676 prescriptions inhibiting organic cation transporter 2.Conclusion:There is no incompatibility between the outpatient prescriptions containing metformin and the commonly used drugs for chronic diseases, but the outpatient doctors do not have enough knowledge about dose adjustment caused by potential interaction.
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ObjectiveTo investigate the effect of Quzhi Ruangan decoction on the mRNA and protein expression of organic anion transporting polypeptide 2B1 (OATP2B1) in the small intestine of rats with nonalcoholic fatty liver disease (NAFLD). MethodsAfter 1 week of adaptive feeding, 36 male Sprague-Dawley rats were randomly divided into normal group, model group, simvastatin group, and high-, middle-, and low-dose Quzhi Ruangan decoction groups, with 6 rats in each group. Liver tissue was collected and HE staining was used to observe hepatic steatosis; an automatic biochemical analyzer was used to measure the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose (GLU), and cholesterol (CHOL); RT-PCR and Western blot were used to measure the mRNA and protein expression of OATP2B1 in the small intestine of rats. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups. Results There were significant differences in liver index, GLU, and CHOL between groups (F=10.814, 12.298, and 5.024, all P＜0.05), and there were also significant differences in the mRNA and protein expression of OATP2B1 in the small intestine (F=13.384 and 73.025, both P＜0.05). Compared with the normal group, the model group had significant increases in the mRNA and protein expression of OATP2B1 (both P＜0.05); compared with the model group, the simvastatin group and the high- and middle-dose Quzhi Ruangan groups had a significant reduction in the mRNA expression of OATP2B1 (all P＜0.05); compared with the simvastatin group, the middle- and low-dose Quzhi Ruangan groups had a significant reduction in the mRNA expression of OATP2B1 (both P＜0.05). Compared with the normal group, the model group had a significant increase in the protein expression of OATP2B1 (P＜0.05); compared with the model group, all treatment groups had a significant reduction in the protein expression of OATP2B1 (all P＜0.001); compared with the simvastatin group, the high-, middle-, and low-dose Quzhi Ruangan groups had a significant reduction in the protein expression of OATP2B1 (all P＜0.05). ConclusionQuzhi Ruangan decoction may alleviate the pathological changes of NAFLD by reducing the overexpression of OATP2B1.
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OBJECTIVEP: To investigate the effect of flavonoids and triterpenoids on the function of organic anion transporting polypeptide 1B3. METHODS: Natural products such as flavonoids and triterpenoids are widely present in traditional Chinese medicine and daily diets. In the present study, CHO cells stably expressing OATP1B3 and its fluorescent substrate fluorescein methotrexate were employed to investigate the effect of 21 natural products on the function of OATP1B3. RESULTS: Mulberrin, glycyrrhetinic acid, glycyrrhizic acid, quercitrin, quercetin, and chrysanthemum stem-leaf flavonoids showed significant inhibitory effects on OATP1B3-mediated uptake of fluorescein methotrexate, with IC50 values being of 3.6, 3.8, 7.5, 9.0, 10.1 μmol•L-1, and 4.1 μg•mL-1, respectively. The IC50 value of glycyrrhetinic acid on OATP1B3 was comparable to its blood concentration in clinics, indicating an OATP1B3-mediated drug-drug interaction could occur. CONCLUSION: Some flavonoids and triterpenoids are OATP1B3 inhibitors. When patients take medications of OATP1B3 substrates, care should be taken to avoid coadmistration of drugs or food containing these inhibitors to circumvent the occurrence of adverse drug interactions.
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Organic anion transporter 3 (OAT3) plays a vital role in removing a broad variety of anionic drugs from kidney, thus avoiding their possible toxicity in the body. In the current study, we investigated the role of insulin-like growth factor 1 (IGF-1) in the regulation of OAT3. We showed that IGF-1 induced a dose- and time-dependent increase in OAT3 transport activity, which correlated well with an increase in OAT3 expression. The IGF-1-induced increase in OAT3 expression was blocked by protein kinase A (PKA) inhibitor H89. Moreover, IGF-1 induced an increase in OAT3 phosphorylation, which was also blocked by H89. These data suggest that the IGF-1 modulation of OAT3 occurred through PKA signaling pathway. To further confirm the involvement of PKA, we treated OAT3-expressing cells with PKA activator Bt2-cAMP, followed by examining OAT activity and phosphorylation. We showed that OAT3 activity and phosphorylation were much enhanced in Bt2-cAMP-treated cells as compared to that in control cells. Finally, linsitinib, an anticancer drug that blocks the IGF-1 receptor, abrogated IGF-1-stimulated OAT3 transport activity. In conclusion, our study demonstrated that IGF-1 regulates OAT3 expression and transport activity through PKA signaling pathway, possibly by phosphorylating the transporter.
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Objective@#The characteristics of T1 relaxation values and the expression levels of organic anion transport system (OATP) and multidrug resistance protein carrier (MRP) on hepatocyte surface membrane were quantitatively studied to evaluate liver function in normal C57BL/6 mice with gadoxetic disodium-enhanced MRI.@*Methods@#Ten 6-weeks-old, normal C57BL/6 mice were included in this study. Gadoxetic disodium- enhanced MRI examination was performed. Longitudinal relaxation time images before and 20 min after contrast injection (hepatobiliary-specific phase) were acquired. T1-relaxation time, T1 relaxation time decline rate (△T) and rapid initial enhancement slope percentage in the first-pass study of the liver parenchyma before and after administration of gadoxetate disodium were measured. Liver parenchyma specimens were detected by Western blotting and the values of OATP1, MRP2, and MRP3 were recorded. Statistical results were expressed in mean.@*Results@#The mean T1 relaxation time of 10 normal C57BL/6 mice before and after enhancement was 659.13 ± 24.07, and 408.87 ± 27.21 ms. The mean T1 relaxation time decline rate and rapid initial enhancement slope percentage in the first-pass study was 37.12% ± 4.95% and 4.14% ± 0.96% ms. Furthermore, the mean value of OATP1, MRP2 and MRP3 were 29 952.1 ± 11 475.2, 34 376.4 ± 33 228.4 and 357 308.9 ± 64 646.5.@*Conclusion@#T1-relaxation values, T1 relaxation time decline rate and rapid initial enhancement slope percentage in the first-pass study before and after gadoxetic disodium-enhanced MRI were determined in normal C57BL/6 mice as well as quantitative values of OATP1, MRP2 and MRP3 at the molecular level on the hepatocyte surface membrane were helpful for liver injury model with control study.
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Gout and hyperuricemia, the frequently-occurring and common diseases, are mainly characterized by the rise of serum uric acid levels. Overproduction and/or underexcretion of uric acid are the primary causes of hyperurice- mia. As an important organ for uric acid elimination, the kidney is responsible for 2/3 uric acid excretion. Recent researches have shown that urate transporters mediate the urate reabsorption and secretion in proximal kidney tubules. The abnormal expression and functional changes of urate transporters are closely related to the occurrence and develop- ment of hyperuricemia. Recently, studies on the urate transporters have achieved great progresses, including the progress in the studies on the urate-anion transporter 1(URAT1), glucose transporter 9, ABC transporter family, sodium-depen- dent phosphate transport protein 1(NPT1), NPT4, and organic anion transporter family, etc. The roles of organic anion transporters(OAT, such as OAT1, OAT2, OAT3, OAT4, OAT10 and URAT1)in renal uric acid excretion are summa- rized in this review.
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By reviewing the relevant domestic and foreign literature of organic anion transporters(organic anion transporting polypeptides,OATP),the research on subtypes,regulation mechanisms,distribution,effect and influenc- ing factors of OATP is summarized. OTAP acts as a transporter widely distributed in humans and rodents,and their pro- tein structure is not exactly the same in different species. There are also differences in the distribution of OTAP in various organs in the same species,and the ability of OTAP to transport substances is different. When multiple drugs or foods are taken at the same time,they may interact through OATP,resulting in the decreased efficacy and increased adverse reac- tions of drugs. More research is needed on the exploration of OATP subtypes and mechanisms.
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Objective The single nucleotide polymorphisms (SNPs) of APOE and SLCO1B1 were examined to explore their association with the risk and severity of coronary heart disease(CAD). Methods A total of 1267 cases of consecutive coronary heart disease (CAD)-suspected inpatients visiting department of Cardiology in Peking University Peoples' Hospital from March 2017 to november were recruited into this case-control study, and then 391 CAD cases and 223 non-CAD controls were enrolled for final analysis after screening by coronary angiography and exclusion criteria. The severity of the CAD cases were evaluated according to Gensini scores. The SNPs of APOE(388T>C, 526C>T) and SLCO1B1(388A>G, 521T>C) were detected using Real-time PCR and further verified using Sanger sequencing. Environmental risk factors were collected, and the correlations between SNPs of APOE and SLCO1B1 and the risk and severity of CAD were performed by SPSS version 16.0. Results The SNPs of all the subjects included in CAD group and non-CAD group were successfully detected, with an accordance of 100％ to Sanger sequencing. The distribution of APOE and SLCO1B1 gene were subjected to Hardy-Weinberg. The distributions of APOE gene ε3/ε3 genotypes and ε3 allele were most commonly found in both CAD group and non-CAD group (ε3/ε3: 70.8％,73.1％;ε3: 83.5％,85.2％;respectively). APOE genotypes and alleles were comparable between the CAD cases and non-CAD controls (P>0.05). The frequencies of APOE gene ε4+genotype were more likely to be found in the subgroup of CAD with Gensini score≥72 (P<0.05). The distributions of SLCO1B1 gene *1b/*1b genotypes and *1b allele were most commonly found in both CAD group and non-CAD group (*1b/*1b: 37.3％, 36.8％; *1b: 60.1％, 61.7％; respectively). There was no significant difference in genotype and allele frequencies of SLCO1B1 between the two groups and among subgroups with different severity of CAD (P>0.05). Conclusion This study observed no association between SNPs of APOE, SLCO1B1 and the risk of CAD in this population. However, APOE gene ε4 +genotype may increase the severity of CAD.
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During the uric acid production, excretion and reabsorption in the liver, kidney and intestine, several uric acid transporter proteins are involved in these processes. A large number of studies have shown that glucose transporter 9 plays an important role in the uric acid transport in the liver, kidney and intestine, and participates in the uric acid reabsorption. The ATP-binding cassette superfamily G member 2 is mainly expressed in the apical membrane of the proximal tubular epithelial cells of the kidney, which is involved in the uric acid secretion. The multidrug resistant protein 4 is expressed in the apical membrane of the renal tubular epithelial cells, which transfers uric acid from the renal tubular epithelial cells into the renal tubular lumen. The urate-anion transporter 1 as well as the organic anion transporters 1 and 3 are all the organic anion transporters belonging to the SLC22 A family of transmembrane transporters, and all participate in the uric acid transport in the kidney, especially the uric acid secretion and excretion. In this review, we summarize the research progress of these uric acid transporters, focusing on their effects on the regulation of the serum uric acid balance.
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The aim of this study was to investigate the renal toxicity of rhubarb and its mechanism. The SD rats were randomly divided into three groups: normal group and two rhubarb extract groups (16, 2 g·kg⁻¹). According to the dose conversion method between human and animal, rhubarb 16 g·kg⁻¹ and 2 g·kg⁻¹ were equivalent to 10 times and 1.25 times of human clinical dose respectively. Rhubarb extract was administered by a gastric gavage to rats once daily for 30 days. Serum urea nitrogen （BUN）, creatinine （CRE） and urine KIM-1, NGAL and renal morphology were analyzed. The expressions of OAT1, OAT3 and clusterin mRNA in kidney were measured. The results showed that the low dose of rhubarb had no obvious renal toxicity. The high dose group showed mild and moderate renal injury and a down-regulation of clusterin mRNA expression in the kidney tissue. The renal toxicity in male animals was heavier than that in female animals. There was no significant change in blood BUN and CRE in the high dose group. But urine NGAL level of the high dose group increased by 51.53% compared with normal group, of which male animals increased more significantly (<0.05, compared with the normal group). The expressions of renal OAT1 and OAT3 mRNA in the low dose group were obviously higher than that in the normal group. The results indicated that the high dose of rhubarb could cause the renal toxicity. The dosage should be controlled reasonably in the clinical use. OAT1 and OAT3 mRNA related to anionic transport in kidney tissue played a compensatory protective role in rhubarb-induced renal injury. But the compensatory effect is relatively weak at the high dose level. In addition, routine renal function indicators BUN and CRE had limitation for monitoring the kidney toxicity of rhubarb. It is suggested that urine NGAL detection might be helpful for monitoring the renal toxicity of rhubarb.
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Objective To investigate the impacts of c.388A ＞ G polymorphism of the solute carrier organic anion transporter 1B1 (SLCO1B1) gene on lipid-lowering and anti-atherosclerosis effects of atorvastatin in Chinese patients with ischemic stroke.Methods The patients with ischemic stroke whose baseline low-density lipoprotein cholesterol (LDL-C) ＞ 1.8 mmol/L were enrolled prospectively.They received atorvastatin (20 mg/d) for 12 months.The lipid and bilateral carotid intima-media thickness (CIMT) were measured respectively before and after treatment.The CIMT differences between SLCO1B1 c.388A＞G genotype groups were compared.Results A total of 71 patients with ischemic stroke were enrolled,including 5 AA genotype,31 AG genotype,and 35 GG genotype.The A allele frequency was 28.9％ and the G allele frequency was 71.1％.After treatment,the total cholesterol (TC),triglyceride (TG),and LDL-C in all patients were significantly lower than those before treatment,and high-density lipoprotein cholesterol (HDL-C) was significantly increase (all P＜0.001),but CIMT did not have significant change (P=0.475).The proportion of patients whose LDL-C ＜ 1.8 mmol/L or LDL-C decreased ≥50％ in the GG genotype group was significantly higher than the AG + AA genotypes group (74.29％ vs.44.44％;x2 =6.540,P =0.011).Conclusions SLCO1B1 gene c.388A ＞ G polymorphism could influence the lipidlowering effect of atorvastatin,lipid-lowering effect in the GG genotype group was better than that in the AG+ AA genotype group.SLCO1B1 gene c.388A ＞ G polymorphism did not have effect on the antiatherosclerosis effect of atorvastatin,but it might be associated with too short follow-up time.
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Objective To establish double-transfected Madin-Darby canine kidney (MDCK) [Ⅱ cells expressing human organic anion transporting polypeptide 1B1 (hOATP1B1) and multidrug resistanceassociated protein 2 (hMRP2)and to testify their functions,moreover,to study the transcellur transport of indoleamine 2,3-dioxygenase (IDO) inhibitor 1-methyltryptophan (1-MT) in the transfectants.Methods hOATP1B1/hMRP2 eukaryotic vectors pVITRO2-SLCO1B1-ABCC2 was obtained by genetic engineering method and then transfected into MDCK cells.Stably expressed MDCK cells were screened by using the geneticin G418.Real-time PCR,Western blot analysis and immuno fluorescent confocal microscopy were used to verify the proteins expression.Transport of the representative substrate pravastatin in different pH values and substrate concentrations and 1-MT were evaluated using the double transfectants.Results MDCK-OATP1B1/MRP2 was successfully established.Pravastatin displayed the optimal transcellular transport when pH value was 6.5.Transport of pravastatin demonstrated the concentration-dependent in the concertation range of 0) to 500 μmol/L.Transport of 1-MT showed no significant difference in MDCK cells and transfectants.Conclusions MDCK-OATP1B1/MRP2 was successful established;1-MT was not the substrate of OATP1B1 or MRP2 protein;and the eatablished double transfectant cell lines can be used to evaluate OATP1B1/MRP2-medicated transport of xenobiotics (e.g.new drug candidates) and endogenous compounds (e.g.bilirubin).
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Aim To investigate the effect of green tea polyphenols(GTP)on serum level of uric acid in potas-sium oxonate (PO)-induced hyperuricemic mice,and explore the potential mechanism.Methods PO and GTP were intragastricly administered to mice for seven consecutive days.Uric acid level in serum was exam-ined.Meanwhile,activity and expressions of xanthine oxidase(XOD)in liver were tested.In additon,ex-pressions of urate transporters including urate-anion transporter (URAT ) 1 , organic anion transporter (OAT)1 and 3 in kidney were analyzed.Results GTP significantly decreased the serum level of uric acid in PO-induced hyperuricemic mice.At the same time, GTP markedly reduced the activity and expression of XOD in liver of hyperuricemic mice.Finally,GTP markedly reduced the expression of URAT1 ,OAT1 and OAT3 in kidney of hyperuricemic mice.Conclusion GTP has the effect of lowering uric acid in PO-induced hyperuricemic mice through both decreasing the uric acid production and increasing uric acid excretion.
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OBJECTIVE: To establish a cell model stably expressing mouse organic anion transporter1( OAT1) in MDCK cells, for the purpose of screening potent OAT1 inhibitors in vitro. METHODS: Recombinant plasmid pcDNA3.1(+) -OAT1 was constructed and transfected into MDCK cells using Lipofectamine™ 2000 reagent. After the process of G418 screening, cells were collected for further validation. Cells were harvested, and the quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) was carried out to test the OAT1 mRNA expression in MDCK-OAT1 cells. The function of the stably transfected cells were validated by the uptake activity of (6-Carboxyfluorescein, 6-CFL),a substrate of OAT1. The inhibitors of OAT1 were selected according to their inhibition activity towards the uptake of 6-CFL into the OAT1-over expressing cells in comparison with the typical inhibitor of OAT1,probenecid. RESULTS: The pcDNA3.1(+) -OAT1 was well conducted. The mRNA expression of OAT1 was significantly higher than that in mock cells; MDCK-OAT1 cells had a significantly high mRNA expression comparing with the mock cells, being 4 862 fold of that in mock cells. The uptake-ability of 6-CFL in MDCK-OAT1 and MDCK-mock cells was obviously different, with a 14.9 fold increase in comparison with mock cells. In the presence of probenecid and several monomers from Chinese herbs, fluorescence values in cell lysates were reduced to varying degrees, and results showed that rhein, luteolin, chrysin and quercetin could significantly inhibited the 6-CFL uptake mediated by hOAT1,with a reduction of more than 80% of the control. CONCLUSION: The aim to establish a cell model which could stably express OAT1 is achieved. Further study could be done using this cell model, for the screening of potential inhibitors of OAT1 from monomers of Chinese herbs,and then could be used as a tool in the research of herb-drug interaction.
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Organic anion transporters(OAT)belong to a family of poly-specific transporters mainly locate in barrier epithelia such as renal proximal tubule.The solute transporter superfamily(SLC)is mainly distributed in the renal proximal convoluted tubules and located in other organs such as the brain,liver and placenta.They are mainly responsible for the reabsorption and secretion of en?dogenous and exogenous organic anions.OAT interact with endogenous metabolic end products such as urate and acidic neutrotransmit?ter metabolites,as well as a multitude of widely used drugs,and play an important role in the excretion and pharmacokinetics of drugs. This article reviews the recent progress in the research of the members of the OAT family.
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The body is exposed to various organic anions,so it is the best way to remove the toxic substances in the body quickly and effectively.Cross epithelial active transport mediated by organic anion transporter is the rate limiting process.Renal secretion and re-absorption of a variety of endogenous and exogenous organic anions are occurred in the proximal tubular epithelial cells of the organic anion transporter family.The expression of organic anion transporter-1 (OAT1) in proximal tubular epithelial cells plays an important role in the introduction of organic anion into the renal tubular epithelial cells.This article reviewed the renal expression,the substrate and the polymorphism of the organic anion transport protein OAT1,the renal toxicity of adefovir dipivoxil,the interaction between organic anion transporters and drug,and the influence of the renal toxicity on the renal toxicity of adefovir dipivoxil.
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This study was designed to explore the effect and mechanism of miR-206/miR-613 on the expression of OATP1B1 gene. Bioinformatic analysis was used to predict the potential miRNAs target sites in 3'-untranslated region (3'-UTR) of OATP1B1 mRNA. The expression level of miR-206/miR-613 and OATP1B1 mRNA and protein was determined with RT-qPCR and Western blot, respectively. Luciferase assay was used to explore the exact mechanism of the effect of miR-206/miR-613 on the expression of OATP1B1 mRNA and protein. The results showed that the seed sequences of miR-206/miR-613 has perfect complementary with 3'-UTR of OATP1B1 mRNA in terms of sequence specificity. The secondary structure between miR-206/miR-613 and 3'-UTR of OATP1B1 mRNA was rather stable. The OATP1B1 protein level was down-regulated by 24.7%, 38.8% by overexpression of miR-206/miR-613. The expression was up-regulated by 25%, 38.2% by inhibition of miR-206/miR-613. However, overexpression or inhibition of miR-206/miR-613 had no effect on the expression of OATP1B1 mRNA. The luciferase activity of pMIR/OATP1B1-WT luciferase reporter gene was decreased by 35% and 30% through overexpression of miR-206/miR-613. The expression was increased by 33.1% and 32.5% through inhibition of miR-206/miR-613. When the binding sites in the 3'-UTR of OATP1B1 mRNA complementary with miR-206/miR-613 was mutated, overexpression or inhibition of miR-206/miR-613 had no effect on the luciferase activity. Collectively, miR-206/miR-613 post-transcriptionally regulates the expression of OATP1B1 protein by directly targeting the 3'-UTR of OATP1B1 mRNA.
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The organic anion transporter (OAT) subfamily is an important part of the SLC22(solute carrier 22) transporter family. OATs are expressed in many tissues, including liver, kidney, brain, placenta and so on. A great deal of attention has been paid to OAT because of its role in handling of common drugs (antibiotics, antivirals, diuretics, nonsteroidal anti-inflammatory drugs), toxins and nutrients. Data from recent metabolomics, microarray and system biology studies, phenotypes of Oat1 and Oat3 knockouts, indicate a central role of this pathway in the metabolism as well as putative uremic toxins of kidney disease. The expressions of certain OATs in conjunction with phase I and phase II drug metabolizing enzymes are regulated by nuclear receptors and other transcription factors. According to the "remote sensing and signaling hypothesis", some OATs have a strong relationship with certain particular signaling molecules. OATs may play a role in remote inter-organ communication via regulating levels of signaling molecules and key metabolites in tissues and body fluids. OATs play a significant role in the transportation of internal and external material under normal and pathological conditions.