Inhibition of initial transport rate of basolateral  organic anion carrier in renal PT by BK and phenylephrine

The effect of ligands for phospholipase C-coupled receptors and of protein kinase C (PKC) stimulation with phorbol ester [phorbol 12-myristate 13-acetate (PMA)] or 1,2-dioctanoyl- sn-glycerol on the activity of the basolateral organic anion transporter (OAT) in S2 segments of single, nonperfused rabbit proximal tubules (PT) was measured with the use of fluorescein and epifluorescence microscopy. The initial uptake rate (25 s, OAT activity) was measured in real time by using conditions similar to those found in vivo. Stimulation of PKC with PMA or 1,2-dioctanoyl- sn-glycerol led to an inhibition of OAT activity, which could be prevented by 10−7 mol/l of the PKC-specific inhibitor bisindolylmaleimide. The α1-receptor agonist phenylephrine as well as the peptide hormone bradykinin induced a reversible decrease of OAT activity, which was prevented by bisindolylmaleimide. The observed effect was not due to a decrease in the concentration of the counterion α-ketoglutarate or to impaired α-ketoglutarate recycling, because it was unchanged in the continuous presence of α-ketoglutarate or methyl succinate. We conclude that physiological stimuli can inhibit the activity of OAT in rabbit PT via PKC. The effect is not mediated by alterations in counterion availability but by a direct action on the OAT.

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Application of a PBPK Model of Rivaroxaban to Prospective Simulations of Drug-Drug-Disease Interactions with Protein Kinase Inhibitors in CA-VTE

10.22541/au.162502338.80368982/v1 ◽

2021 ◽

Author(s):

Eleanor Jing Yi Cheong ◽

Daniel Zhi Wei Ng ◽

Sheng Yuan Chin ◽

Ziteng Wang ◽

Eric Chun Yong Chan

Keyword(s):

Protein Kinase ◽

Kinase Inhibitors ◽

Pbpk Model ◽

Organic Anion ◽

Protein Kinase Inhibitors ◽

Organic Anion Transporter ◽

Pbpk Modelling ◽

Anion Transporter

Background and Purpose Rivaroxaban is emerging as a viable anticoagulant for the pharmacological management of cancer associated venous thromboembolism (CA-VTE). Being eliminated via CYP3A4/2J2-mediated metabolism and organic anion transporter 3 (OAT3)/P-glycoprotein-mediated renal secretion, rivaroxaban is susceptible to drug-drug interactions (DDIs) with protein kinase inhibitors (PKIs), erlotinib and nilotinib. Physiologically based pharmacokinetic (PBPK) modelling was applied to interrogate the DDIs for dose adjustment of rivaroxaban in CA-VTE. Experimental Approach The inhibitory potencies of erlotinib and nilotinib on CYP3A4/2J2-mediated metabolism of rivaroxaban were characterized. Using prototypical OAT3 inhibitor ketoconazole, in vitro OAT3 inhibition assays were optimized to ascertain the in vivo relevance of derived inhibitory constants (K). DDIs between rivaroxaban and erlotinib or nilotinib were investigated using iteratively verified PBPK model. Key Results Mechanism-based inactivation (MBI) of CYP3A4-mediated rivaroxaban metabolism by both PKIs and MBI of CYP2J2 by erlotinib were established. The importance of substrate specificity and nonspecific binding to derive OAT3-inhibitory K values of ketoconazole and nilotinib for the accurate prediction of DDIs was illustrated. When simulated rivaroxaban exposure variations with concomitant erlotinib and nilotinib therapy were evaluated using published dose-exposure equivalence metrics and bleeding risk analyses, dose reductions from 20 mg to 15 mg and 10 mg in normal and mild renal dysfunction, respectively, were warranted. Conclusion and Implications We established the PBPK-DDI platform to prospectively interrogate and manage clinically relevant interactions between rivaroxaban and PKIs in patients with underlying renal impairment. Rational dose adjustments were proposed, attesting to the capacity of PBPK modelling in facilitating precision medicine.

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In vivo Cisplatin Resistance Depending upon Canalicular Multispecific Organic Anion Transporter (cMOAT)

Japanese Journal of Cancer Research ◽

10.1111/j.1349-7006.1999.tb00692.x ◽

1999 ◽

Vol 90 (10) ◽

pp. 1171-1178 ◽

Cited By ~ 8

Author(s):

Tomoyoshi Minamino ◽

Mitsuo Tamai ◽

Yoshie Itoh ◽

Yasuaki Tatsumi ◽

Masaaki Nomura ◽

...

Keyword(s):

Cisplatin Resistance ◽

Organic Anion ◽

Organic Anion Transporter ◽

Anion Transporter

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Interactions of 172 plant extracts with human organic anion transporter 1 (SLC22A6) and 3 (SLC22A8): a study on herb-drug interactions

PeerJ ◽

10.7717/peerj.3333 ◽

2017 ◽

Vol 5 ◽

pp. e3333 ◽

Cited By ~ 10

Author(s):

Hang Lu ◽

Zhiqiang Lu ◽

Xue Li ◽

Gentao Li ◽

Yilin Qiao ◽

...

Keyword(s):

Drug Interactions ◽

Plant Extracts ◽

Organic Anion ◽

Organic Anion Transporter ◽

Hek293 Cells ◽

Pharmacokinetic Parameters ◽

Renal Elimination ◽

Juncus Effusus ◽

Anion Transporter

BackgroundHerb-drug interactions (HDIs) resulting from concomitant use of herbal products with clinical drugs may cause adverse reactions. Organic anion transporter 1 (OAT1) and 3 (OAT3) are highly expressed in the kidney and play a key role in the renal elimination of substrate drugs. So far, little is known about the herbal extracts that could modulate OAT1 and OAT3 activities.MethodsHEK293 cells stably expressing human OAT1 (HEK-OAT1) and OAT3 (HEK-OAT3) were established and characterized. One hundred seventy-two extracts from 37 medicinal and economic plants were prepared. An initial concentration of 5 µg/ml for each extract was used to evaluate their effects on 6-carboxylfluorescein (6-CF) uptake in HEK-OAT1 and HEK-OAT3 cells. Concentration-dependent inhibition studies were conducted for those extracts with more than 50% inhibition to OAT1 and OAT3. The extract ofJuncus effusus, a well-known traditional Chinese medicine, was assessed for its effect on thein vivopharmacokinetic parameters of furosemide, a diuretic drug which is a known substrate of both OAT1 and OAT3.ResultsMore than 30% of the plant extracts at the concentration of 5 µg/ml showed strong inhibitory effect on the 6-CF uptake mediated by OAT1 (61 extracts) and OAT3 (55 extracts). Among them, three extracts for OAT1 and fourteen extracts for OAT3 were identified as strong inhibitors with IC50values being <5 µg/ml.Juncus effususshowed a strong inhibition to OAT3in vitro, and markedly altered thein vivopharmacokinetic parameters of furosemide in rats.ConclusionThe present study identified the potential interactions of medicinal and economic plants with human OAT1 and OAT3, which is helpful to predict and to avoid potential OAT1- and OAT3-mediated HDIs.

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Cytotoxicity of Antiviral Nucleotides Adefovir and Cidofovir Is Induced by the Expression of Human Renal Organic Anion Transporter 1

Journal of the American Society of Nephrology ◽

10.1681/asn.v113383 ◽

2000 ◽

Vol 11 (3) ◽

pp. 383-393 ◽

Cited By ~ 3

Author(s):

EDMUND S. HO ◽

DEBORAH C. LIN ◽

DIRK B. MENDEL ◽

TOMAS CIHLAR

Keyword(s):

Organic Anion ◽

Critical Role ◽

Antiviral Agents ◽

Chinese Hamster ◽

Organic Anion Transporter ◽

Nucleotide Analogs ◽

Anion Transporter ◽

Organ Specific

Abstract. The transport of organic anions in proximal convoluted tubules plays an essential role in the active secretion of a variety of small molecules by the kidney. In addition to other anionic substrates, the human renal organic anion transporter 1 (hOAT1) is capable of transporting the nucleotide analogs adefovir and cidofovir. To investigate the involvement of hOAT1 in the mechanism of nephrotoxicity associated with these two clinically important antiviral agents, Chinese hamster ovary (CHO) cells were stably transfected with hOAT1 cDNA. The resulting CHOhOAT cells showed probenecid-sensitive and pH-dependent uptake of p-aminohippurate (Km = 15.4 μM, Vmax = 20.6 pmol/106 cells · min), a prototypical organic anion substrate. In addition, the stably expressed hOAT1 mediated efficient transport of adefovir (Km = 23.8 μM, Vmax = 46.0 pmol/106 cells · min) and cidofovir (Km = 58.0 μM, Vmax = 103 pmol/106 cells · min) such that the levels of intracellular metabolites of both nucleotides were >100-fold higher in CHOhOAT cells than in parental CHO. Consequently, adefovir and cidofovir were approximately 500-fold and 400-fold more cytotoxic, respectively, in CHOhOAT cells compared to CHO. The cytotoxicity of both drugs in CHOhOAT cells was markedly reduced in the presence of hOAT1 inhibitors. The cyclic prodrug of cidofovir, which exhibits reduced in vivo nephrotoxicity, was a poor substrate for hOAT1 and showed only marginally increased cytotoxicity in CHOhOAT cells. In conclusion, these studies demonstrate that hOAT1 plays a critical role in the organ-specific toxicity of adefovir and cidofovir, and indicates that CHOhOAT cells may represent a useful in vitro model to investigate the potential nephrotoxicity of clinically relevant organic anion agents.

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Peritubular transport of ochratoxin A by single rabbit renal proximal tubules.

Journal of the American Society of Nephrology ◽

10.1681/asn.v9111973 ◽

1998 ◽

Vol 9 (11) ◽

pp. 1973-1982 ◽

Cited By ~ 1

Author(s):

J R Welborn ◽

C E Groves ◽

S H Wright

Keyword(s):

Proximal Tubule ◽

Ochratoxin A ◽

Organic Anion ◽

High Capacity ◽

Organic Anion Transporter ◽

Epifluorescence Microscopy ◽

Proximal Tubule Cells ◽

Anion Transporter ◽

Uptake Medium ◽

Proximal Tubule Segments

Epifluorescence microscopy was used to study peritubular transport of the fluorescent mycotoxin ochratoxin A (OTA) into single proximal tubule segments of the rabbit. Initial rates of OTA uptake into S2 segments were saturable and adequately described by Michaelis-Menten kinetics, with an apparent Km of 2.2+/-0.3 microM (SEM). Several lines of evidence indicated that peritubular uptake of OTA in S2 segments was effectively limited to the "classical" organic anion transporter. First, 5 mM p-aminohippurate (PAH) cis-inhibited the uptake of 1 microM OTA into tubules by 96%. Kinetic analysis of the inhibition of OTA uptake by PAH (100 microM to 5 mM) yielded an apparent Ki of 164 microM, similar to the 100 to 200 microM range of Km values previously reported for the peritubular uptake of PAH. Second, efflux of OTA from tubules was trans-stimulated 3.2-fold by the presence of 2.5 mM PAH in the uptake medium. Third, 100 microM alpha-ketoglutarate (alphaKG) trans-stimulated the uptake rate of 1 microM OTA by 1.8-fold. Fourth, besides PAH, other organic anions effectively cis-inhibited the uptake of 1 microM OTA into tubules (inhibitor, % inhibition): 1.5 mM alphaKG, 80%; 1 mM probenecid, 100%; 1 mM piroxicam, 100%; 1 mM octanoate, 100%. In contrast, 1.5 mM tetraethylammonium, an organic cation, blocked uptake of 1 microM OTA by only 7%. The inhibition of OTA uptake into S1 and S3 segments of the proximal tubule was qualitatively similar: 5 mM PAH cis-inhibited the uptake of 1 microM OTA by approximately 95% in both S1 and S3 segments. Thus, peritubular OTA uptake into all segments of the proximal tubule appears to be dominated by its interaction with the classical organic anion transporter. The high-affinity and relatively high capacity of this pathway for OTA suggest that peritubular uptake may be a significant avenue for the entry of this toxin into proximal tubule cells.

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AG490, a JAK2-specific inhibitor, downregulates the expression and activity of organic anion transporter-3

Journal of Pharmacological Sciences ◽

10.1016/j.jphs.2018.01.006 ◽

2018 ◽

Vol 136 (3) ◽

pp. 142-148 ◽

Cited By ~ 5

Author(s):

Jinghui Zhang ◽

Chenchang Liu ◽

Guofeng You

Keyword(s):

Organic Anion ◽

Specific Inhibitor ◽

Organic Anion Transporter ◽

Anion Transporter ◽

Organic Anion Transporter 3 ◽

Expression And Activity

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Mammalian colonocytes possess a carrier-mediated mechanism for uptake of vitamin B3 (niacin): studies utilizing human and mouse colonic preparations

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00148.2013 ◽

2013 ◽

Vol 305 (3) ◽

pp. G207-G213 ◽

Cited By ~ 11

Author(s):

Jeyan S. Kumar ◽

Veedamali S. Subramanian ◽

Rubina Kapadia ◽

Moti L. Kashyap ◽

Hamid M. Said

Keyword(s):

Nicotinic Acid ◽

Large Intestine ◽

Protein Tyrosine Kinase ◽

Organic Anion ◽

Organic Anion Transporter ◽

Vitamin B3 ◽

Regulatory Pathways ◽

Anion Transporter

Niacin (vitamin B3; nicotinic acid) plays an important role in maintaining redox state of cells and is obtained from endogenous and exogenous sources. The latter source has generally been assumed to be the dietary niacin, but another exogenous source that has been ignored is the niacin that is produced by the normal microflora of the large intestine. For this source of niacin to be bioavailable, it needs to be absorbed, but little is known about the ability of the large intestine to absorb niacin and the mechanism involved. Here we addressed these issues using the nontransformed human colonic epithelial NCM460 cells, native human colonic apical membrane vesicles (AMV) isolated from organ donors, and mouse colonic loops in vivo as models. Uptake of3H-nicotinic acid by NCM460 cells was: 1) acidic pH (but not Na+) dependent; 2) saturable (apparent Km= 2.5 ± 0.8 μM); 3) inhibited by unlabeled nicotinic acid, nicotinamide, and probenecid; 4) neither affected by other bacterially produced monocarboxylates, monocarboxylate transport inhibitor, or by substrates of the human organic anion transporter-10; 5) affected by modulators of the intracellular protein tyrosine kinase- and Ca2+-calmodulin-regulatory pathways; and 6) adaptively regulated by extracellular nicotinate level. Uptake of nicotinic acid by human colonic AMV in vitro and by mouse colonic loops in vivo was also carrier mediated. These findings report, for the first time, that mammalian colonocytes possess a high-affinity carrier-mediated mechanism for nicotinate uptake and show that the process is affected by intracellular and extracellular factors.

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Transport of cimetidine by flounder and human renal organic anion transporter 1

AJP Renal Physiology ◽

10.1152/ajprenal.00290.2002 ◽

2003 ◽

Vol 284 (3) ◽

pp. F503-F509 ◽

Cited By ~ 30

Author(s):

Birgitta C. Burckhardt ◽

Stefan Brai ◽

Sönke Wallis ◽

Wolfgang Krick ◽

Natascha A. Wolff ◽

...

Keyword(s):

Organic Anion ◽

Human Kidney ◽

Organic Anion Transporter ◽

In Vivo Studies ◽

Xenopus Laevis Oocytes ◽

Organic Anion Transporters ◽

Anion Transporters ◽

Anion Transporter ◽

Inward Currents

The H2-receptor antagonist cimetidine is efficiently excreted by the kidneys. In vivo studies indicated an interaction of cimetidine not only with transporters for basolateral uptake of organic cations but also with those involved in excretion of organic anions. We therefore tested cimetidine as a possible substrate of the organic anion transporters cloned from winter flounder (fROAT) and from human kidney (hOAT1). Uptake of [3H]cimetidine into fROAT-expressing Xenopus laevis oocytes exceeded uptake into control oocytes. At −60-mV clamp potential, 1 mM cimetidine induced an inward current, which was smaller than that elicited by 0.1 mM PAH. Cimetidine concentrations exceeding 0.1 mM decreased PAH-induced inward currents, indicating interaction with the same transporter. At pH 6.6, no current was seen with 0.1 mM cimetidine, whereas at pH 8.6 a current was readily detectable, suggesting preferential translocation of uncharged cimetidine by fROAT. Oocytes expressing hOAT1 also showed [3H]cimetidine uptake. These data reveal cimetidine as a substrate for fROAT/hOAT1 and suggest that organic anion transporters contribute to cimetidine excretion in proximal tubules.

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Involvement of Organic Anion Transporters in the Pharmacokinetics and Drug Interaction of Rosmarinic Acid

Pharmaceutics ◽

10.3390/pharmaceutics13010083 ◽

2021 ◽

Vol 13 (1) ◽

pp. 83

Author(s):

Yun Ju Kang ◽

Chul Haeng Lee ◽

Soo-Jin Park ◽

Hye Suk Lee ◽

Min-Koo Choi ◽

...

Keyword(s):

Drug Interaction ◽

Rosmarinic Acid ◽

Renal Excretion ◽

Organic Anion ◽

Plasma Concentrations ◽

Pharmacokinetic Interaction ◽

Organic Anion Transporter ◽

Hek293 Cells ◽

Anion Transporter

We investigated the involvement of drug transporters in the pharmacokinetics of rosmarinic acid in rats as well as the transporter-mediated drug interaction potential of rosmarinic acid in HEK293 cells overexpressing clinically important solute carrier transporters and also in rats. Intravenously injected rosmarinic acid showed bi-exponential decay and unchanged rosmarinic acid was mainly eliminated by urinary excretion, suggesting the involvement of transporters in its renal excretion. Rosmarinic acid showed organic anion transporter (OAT)1-mediated active transport with a Km of 26.5 μM and a Vmax of 69.0 pmol/min in HEK293 cells overexpressing OAT1, and the plasma concentrations of rosmarinic acid were increased by the co-injection of probenecid because of decreased renal excretion due to OAT1 inhibition. Rosmarinic acid inhibited the transport activities of OAT1, OAT3, organic anion transporting polypeptide (OATP)1B1, and OATP1B3 with IC50 values of 60.6 μM, 1.52 μM, 74.8 μM, and 91.3 μM, respectively, and the inhibitory effect of rosmarinic acid on OAT3 transport activity caused an in vivo pharmacokinetic interaction with furosemide by inhibiting its renal excretion and by increasing its plasma concentration. In conclusion, OAT1 and OAT3 are the major transporters that may regulate the pharmacokinetic properties of rosmarinic acid and may cause herb-drug interactions with rosmarinic acid, although their clinical relevance awaits further evaluation.

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