Organic ion transporters are expressed in various tissues that transport endogenous and exogenous compounds including their metabolites. There are organic anion transporter (OAT), organic cation transporter (OCT), organic anion transporter like protein (OATLP) and organic cation transporter like (OCTL). Considering the variety of charged organic ionic compounds, the existence of numerous isoforms of organic ion transporters can be assumed. In the present study, we have searched for a new isoform in the expressed sequence tag (EST) database using human organic anion transporter 4 (hOAT4) amino acid sequence as a "query". We found a candidate clone (BC021449) from the mouse kidney cDNA library. This clone was identified as an ortholog of ORCTL3 or OCTL-1. The mOCTL1 cDNA consists of 2016 base pairs encoding 551 amino acid residues with 12 putative transmembrane domains. The deduced amino acid sequence of mOCTL1 showed 35 to 40% identity to those of the other members of the OATs and OCTs. According to the tissue distribution, examined by Northern blot analysis, about a 2.4-kb transcript of mOCTL1 was observed in the kidney. About a 90-kDa band was detected when Western blot analysis in the mouse kidney was done by using antibody against synthesized oligopeptide of mOCTL1. The immunohistochemical result showed that mOCTL1 was stained at the glomerulus (the parietal epithelial cells and podocytes), pars recta of proximal tubule, distal convoluted tubules, connecting tubules and collecting tubules. From these results, we conclude that mOCTL1 may be a candidate for an organic ion transporter isoform in the mouse kidney.
Amino Acid Sequence ; Animals ; Blotting, Western ; Gene Library ; Humans ; Immunohistochemistry ; Kidney/*metabolism ; Mice ; Molecular Sequence Data ; Organ Specificity ; Organic Cation Transport Proteins/genetics/*isolation & purification ; Organic Cation Transporter 1/genetics/*isolation & purification ; Protein Isoforms/isolation & purification

Liver is regarded as one of the most important organs for drug clearance in the body, which mediates both the metabolism and biliary excretion of drugs. Transporters are a class of functional membrane proteins and control the movement of substances into or out of cells. Transporters, which are extensively expressed in the liver, play important roles in the drug hepatic disposition by regulating the uptake of drugs from blood into hepatocytes or the efflux of drugs and their metabolites into bile. In this review, the localization, functions and substrate selectivity of the major transporters in the liver will be summarized, and the impacts of these transporters on drug hepatic disposition, the potential drug-drug interactions as well as their genetic polymorphisms will also be reviewed.
ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; genetics ; metabolism ; ATP-Binding Cassette, Sub-Family B, Member 1 ; genetics ; metabolism ; Bile ; metabolism ; Biological Transport ; Drug Interactions ; Humans ; Liver ; metabolism ; Membrane Transport Proteins ; genetics ; metabolism ; Metabolic Clearance Rate ; Multidrug Resistance-Associated Proteins ; genetics ; metabolism ; Neoplasm Proteins ; genetics ; metabolism ; Organic Anion Transporters ; genetics ; metabolism ; Organic Anion Transporters, Sodium-Dependent ; metabolism ; Organic Anion Transporters, Sodium-Independent ; genetics ; metabolism ; Organic Cation Transport Proteins ; genetics ; metabolism ; Pharmacokinetics ; Polymorphism, Genetic ; Symporters ; metabolism

The effects of mangiferin on uric acid excretion, kidney function and related renal transporters were investigated in hyperuricemic mice induced by potassium oxonate. Mice were divided into normal control group, and 5 hyperuricemic groups with model control, 50, 100, and 200 mg x kg(-1) mangiferin, and 5 mg x kg(-1) allopurinol. Mice were administered by gavage once daily with 250 mg x kg(-1) potassium oxonate for seven consecutive days to create the model. And 3 doses of mangiferin were orally initiated on the day 1 h after potassium oxonate was given, separately. Serum uric acid, creatinine and urea nitrogon levels, as well as urinary uric acid creatinine levels were measured. Mouse uromodulin (mUMOD) levels in serum, urine and kidney were determined by ELISA method. The mRNA and protein levels of related renal transporters were assayed by RT-PCR and Western blotting methods, respectively. Compared to model group, mangiferin significantly reduced serum uric acid, creatinine and urea nitrogon levels, increased 24 h uric acid and creatinine excretion, and fractional excretion of uric acid in hyperuricemic mice, exhibiting uric acid excretion enhancement and kidney function improvement. Mangiferin was found to down-regulate mRNA and protein levels of urate transporter 1 (mURAT1) and glucose transporter 9 (mGLUT9), as well as up-regulate organic anion transporter 1 (mOAT1) in the kidney of hyperuricemic mice. These findings suggested that mangiferin might enhance uric acid excretion and in turn reduce serum uric acid level through the decrease of uric acid reabsorption and the increase of uric acid secretion in hyperuricemic mice. Moreover, mangiferin remarkably up-regulated expression levels of renal organic cation and carnitine transporters (mOCT1, mOCT2, mOCTN1 and mOCTN2), increased urine mUMOD levels, as well as decreased serum and kidney mUMOD levels in hyperuricemic mice, which might be involved in mangiferin-mediated renal protective action.
Animals ; Blood Urea Nitrogen ; Carrier Proteins ; genetics ; metabolism ; Creatinine ; blood ; Glucose Transport Proteins, Facilitative ; genetics ; metabolism ; Hyperuricemia ; blood ; chemically induced ; physiopathology ; urine ; Kidney ; metabolism ; physiopathology ; Male ; Membrane Proteins ; genetics ; metabolism ; Mice ; Octamer Transcription Factor-1 ; genetics ; metabolism ; Organic Anion Transport Protein 1 ; genetics ; metabolism ; Organic Anion Transporters ; genetics ; metabolism ; Organic Cation Transport Proteins ; genetics ; metabolism ; Organic Cation Transporter 2 ; Oxonic Acid ; Protective Agents ; pharmacology ; RNA, Messenger ; metabolism ; Random Allocation ; Solute Carrier Family 22 Member 5 ; Uric Acid ; blood ; urine ; Uromodulin ; blood ; urine ; Xanthones ; pharmacology

ATP Binding Cassette Subfamily B Member 11 ; ATP Binding Cassette Transporter, Sub-Family G, Member 2 ; ATP-Binding Cassette Transporters ; physiology ; ATP-Binding Cassette, Sub-Family B, Member 1 ; physiology ; Animals ; Bile ; metabolism ; Biliary Tract ; physiology ; Drug Interactions ; Drug Resistance, Multiple ; Humans ; Liver ; physiology ; Multidrug Resistance-Associated Proteins ; physiology ; Neoplasm Proteins ; physiology ; Organic Anion Transporters ; physiology ; Organic Anion Transporters, Sodium-Dependent ; physiology ; Organic Cation Transport Proteins ; physiology ; Symporters ; physiology

Mammal multidrug and toxin extrusion proteins (MATEs) play an important role in the transport of organic cations in the body. MATEs mediate the final excretion step for multiple organic cation drug used clinically and important endogenous substances. This article reviews the discovery, type, gene coding and polymorphism, body distribution, classification of substrates and inhibitors and their research method of MATEs. The article also discusses the major research significance of MATEs with examples.
Animals ; Biological Transport ; Cations ; Organic Cation Transport Proteins ; metabolism ; Polymorphism, Genetic

BACKGROUNDHuman urate anion exchanger (hURAT1) as a major urate transporter expressed on renal tubular epithelial cells regulates blood urate level by reabsorbing uric acid. Antibody is an important tool to study hURAT1. This study aimed, by genetic immunization, to produce mouse anti-hURAT1 polyclonal antibody with high throughput and high specificity and to detect the location of hURAT1 in human kidney.

METHODSHuman renal total RNA was isolated and the entire cDNA of hURAT1 was amplified by RT-PCR. The sequence of intracellular high antigenicity fragment (A280 to R349) was chosen by prediction software of protein antigenicity, and its cDNA was amplified from cDNA of hURAT1, and then cloned into pBQAP-TT vector to construct recombinant plasmid pBQAP-TT-hURAT1-210 for genetic immunization. Mice were inoculated with this recombinant plasmid and two other adjuvant plasmids, pCMVi-GMCSF and pCMVi-Flt3L, which helped to enhance the antibody's generation. After four weeks, the mice were sacrificed to obtain the anti-hURAT1 antibody from serum. The antibody was identified by western blot analysis and immunohistochemistry. At the same time, rabbit anti-hURAT1 antibody was produced by protein immunization. The specificity and efficiency between the rabbit and mouse anti-hURAT1 antibody were compared by western blot analysis and immunohistochemistry.

RESULTSThe entire cDNA of hURAT1 and cDNA of its intracellular high immunogenic fragment were amplified successfully. Recombinant plasmid pBQAP-TT-hURAT1-210 for genetic immunization was confirmed by restriction digestion and sequencing. Both the mouse anti-hURAT1 antibody and rabbit anti-hURAT1 antibody recognized 58 kD hURAT1 and 64 kD glycosylated hURAT1 protein bands in western blot. Immunohistochemically, hURAT1 was located at the brush border membrane of renal proximal tubular cells. In addition, the throughput and specificity of the mouse anti-hURAT1 antibody were higher than those of the rabbit anti-hURAT1 antibody.

CONCLUSIONGenetic immunization can generate anti-hURAT1 polyclonal antibody of high throughput and specificity.

Animals ; Antibodies ; analysis ; Blotting, Western ; Carrier Proteins ; analysis ; immunology ; Female ; Humans ; Immunization ; Immunohistochemistry ; Kidney ; chemistry ; Male ; Mice ; Organic Anion Transporters ; analysis ; immunology ; Organic Cation Transport Proteins ; Plasmids ; Rabbits

To establish single- and double-transfected transgenic cells stably expressing hMATE1, hMATE1 cDNA was cloned by RT-PCR from human cryopreserved kidney tissue, and subcloned into pcDNA3.1(+) plasmid by virtue of both HindIII and Kpn I restriction enzyme sites. Subsequently, the recombined pcDNA3.1(+)- hMATE1 plasmid was transfected into MDCK, MDCK-hOCT1 or MDCK-hOCT2 cells using Lipofectamine 2000 Reagent. After a 14-day-cultivation with hygromycin B at the concentration of 400 µg · mL(-1), all clones were screened with DAPI and MPP+ as substrates to identify the best candidate. The mRNA content of hMATE1, the cellular accumulation of metformin with or without cimetidine as inhibitor, or transportation of cimetidine was further valuated. The results showed that all of the three cell models over expressed hMATE1 mRNA. The cellular accumulation of metformin in MDCK-hMATE1 was 17.6 folds of the control cell, which was significantly inhibited by 100 µmol · L(-1) cimetidine. The transcellular transport parameter net efflux ratios of cimetidine across MDCK-hOCT1/hMATE1 and MDCK-hOCT2/hMATE1 monolayer were 17.5 and 3.65, respectively. In conclusion, cell models with good hMATE1 function have been established successfully, which can be applied to study the drug transport or drug-drug interaction involving hMATE1 alone or together with hOCT1/2 in vitro.
Animals ; Biological Transport ; Cimetidine ; pharmacology ; DNA, Complementary ; Dogs ; Drug Interactions ; Humans ; Madin Darby Canine Kidney Cells ; Metformin ; pharmacology ; Organic Cation Transport Proteins ; genetics ; metabolism ; Transfection

Objective: To investigate the expressions of solute carrier family 22 member 14 (SLC22A14) and sperm-associated antigen 6 (SPAG6) in the sperm of idiopathic asthenospermia men. METHODS: We collected semen samples from 50 idiopathic asthenozoospermia patients and another 50 normal sperm donors, purified the sperm by discontinuous density centrifugation on Percoll gradients, and then determined the mRNA and protein expressions of SLC22A14 and SPAG6 by RT-PCR and Western blot, respectively. RESULTS: Compared with the normal controls, the idiopathic asthenozoospermia patients showed significantly decreased mRNA expressions of SLC22A14 (0.77 ± 0.08 vs 0.53 ± 0.10, P<0.01) and SPAG6 (0.78 ± 0.09 vs0.52 ± 0.10 , P<0.01) and protein expressions of SLC22A14 (0.80 ± 0.09 vs 0.55 ± 0.10 , P<0.01) and SPAG6 (0.78 ± 0.09 vs 0.56 ± 0.09, P<0.01). CONCLUSIONS T The expressions of SLC22A14 and SPAG6 are reduced in the sperm of the patients with idiopathic asthenospermia, which may be one of the important causes of asthenospermia.
Asthenozoospermia ; metabolism ; Blotting, Western ; Ejaculation ; Humans ; Male ; Microtubule Proteins ; genetics ; metabolism ; Organic Cation Transport Proteins ; genetics ; metabolism ; Proteomics ; RNA, Messenger ; metabolism ; Sperm Motility ; Spermatozoa ; metabolism

Acute renal failure with severe loin pain which develops after anaerobic exercise is rare. One of predisposing factors of exercise-induced acute renal failure is renal hypouricemia. Idiopathic renal hypouricemia is a genetic disorder characterized by hypouricemia with abnormally high renal tubular uric acid excretion. The mutation in SCL22A12 gene which encodes renal uric acid transporter, URAT1, is the known major cause of this disorder. We here described a 25-yr-old man showing idiopathic renal hypouricemia with G774A mutation in SCL22A12 who presented exercise-induced acute renal failure. There have been a few reports of mutational analysis in Korean idiopathic renal hypouricemia without acute renal failure. This is the first report of genetically diagnosed idiopathic renal hypouricemia with exercise-induced acute renal failure in Korea.
Acute Kidney Injury/*diagnosis/genetics ; Adult ; Amino Acid Substitution ; DNA Mutational Analysis ; Exercise ; Exons ; Humans ; Male ; Mutation ; Organic Anion Transporters/*genetics ; Organic Cation Transport Proteins/*genetics ; Renal Tubular Transport, Inborn Errors/etiology/*genetics ; Urinary Calculi/etiology/*genetics

OBJECTIVETo explore the correlation between Pi and Shen by observing the relationship between the metabolism of aristolochic acid (AA) and mRNA and protein expression levels of organic anion transporting polypeptide (oatp) superfamily member 2a1 and 2 b1 (oatp2al and oatp2bl) in renal, small intestinal, and large intestinal tissues of Pi deficiency syndrome (PDS) model rats.

METHODSTotally 46 Sprague-Dawley (SD) rats were randomly divided into four groups, i.e., the blank group (n = 12), the PDS group (n = 22), the AA-I group (n = 6), and the PDS AA-I group (n = 6). PDS model was established by subcutaneously injecting Reserpine at the daily dose of 5 mg/kg for 16 successive days. Carotid intubation was performed in 6 rats selected from the blank group and the PDS group. Pharmacokinetics of AA-I were detected at 5, 15, 30, 45, and 60 min after gastrogavage of AA-I. AA-I concentrations in renal, small intestinal, and large intestinal tissues of 10 rats selected from the PDS group were determined. Normal saline was administered to 6 rats selected from the PDS group and the blank group by gastrogavage. Renal, small intestinal, and large intestinal tissues were collected in the AA-I group and the PDS AA-I group at 60 min after gastrogavage of AA-I. mRNA and protein expression levels of oatp2a1 and oatp2b1 in each tissue were detected using real-time polymerase chain reaction (RT- PCR) and Western blot.

RESULTSCompared with the blank group, plasma concentrations of in vivo AA-I were obviously higher in the PDS group at 15, 30, 45, and 60 min after gastrogavage of AA-I with statistical difference (P < 0.05). Plasma concentrations of AA-I were obviously decreased at 60 min after gastrogavage of AA-I; AA-I concentrations in renal and large intestinal tissues were elevated; AA-I concentrations in small intestinal tissues were obviously reduced in the PDS group. There was no statistical difference in mRNA expression levels of oatp2a1 and oatp2b1 in the aforesaid three tissues of rats between the blank group and the PDS group. Compared with the blank group, mRNA expression levels of oatp2a1 and oatp2b1 decreased in small intestinal tissues of the AA-I group, and the mRNA expression level of oatp2a1 in large intestinal tissues significantly decreased (P < 0.05, P < 0.01). Compared with the PDS group, mRNA expression levels of oatp2a1 and oatp2b1 increased in renal tissues of the PDS AA-I group (P < 0.05); mRNA expression levels of oatp2b1 increased in large intestinal tissues of the PDS AA-I group (P < 0.05).

CONCLUSIONSThe difference in AA-I metabolism might be associated with changed expression levels of oatp2a1 and oatp2b1 in renal, small intestinal, and large intestinal tissues under Pi deficiency induced loss of transportation. Shen and Dachang played important roles in substance metabolism under Pi deficiency state, which proved Pi-Shen correlated in Chinese medical theories.

Animals ; Anions ; Aristolochic Acids ; metabolism ; Drugs, Chinese Herbal ; Kidney ; Medicine, Chinese Traditional ; Organic Cation Transport Proteins ; metabolism ; Peptides ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley