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Stindt J, Dröge C, Lainka E, Kathemann S, Pfister ED, Baumann U, Stalke A, Grabhorn E, Shagrani MA, Mozer-Glassberg Y, Hartley J, Wammers M, Klindt C, Philippski P, Liebe R, Herebian D, Mayatepek E, Berg T, Schmidt-Choudhury A, Wiek C, Hanenberg H, Luedde T, Keitel V. Cell-based BSEP trans-inhibition: A novel, non-invasive test for diagnosis of antibody-induced BSEP deficiency. JHEP Rep 2023. [DOI: 10.1016/j.jhepr.2023.100690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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2
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Jazaeri F, Sheibani M, Nezamoleslami S, Moezi L, Dehpour AR. Current Models for Predicting Drug-induced Cholestasis: The Role of Hepatobiliary Transport System. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2021; 20:1-21. [PMID: 34567142 PMCID: PMC8457732 DOI: 10.22037/ijpr.2020.113362.14254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Drug-induced cholestasis is the main type of liver disorder accompanied by high morbidity and mortality. Evidence for the role of hepatobiliary pumps in the cholestasis patho-mechanism is constantly increasing. Recognition of the interactions of chemical agents with these transporters at the initial phases of drug discovery can help develop new drug candidates with low cholestasis potential. This review delivers an outline of the role of these transport proteins in bile creation. It addresses the pathophysiological mechanism for drug-induced cholestasis. In-vitro models, including cell-based and membrane-based approaches and In-vivo models such as genetic knockout animals, are considered. The benefits and restrictions of each model are discussed in this review. Current understandings into the cellular and molecular process that control the activity of hepatobiliary pumps have directed to a better understanding of the pathophysiology of drug-induced cholestasis. A combination of in-vitro monitoring for transport interaction, in-silico predicting systems, and consideration of and metabolic and physicochemical properties must cause more effective monitoring of possible liver problems.
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Affiliation(s)
- Farahnaz Jazaeri
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,F. J. and M. Sh. contributed equally to this work
| | - Mohammad Sheibani
- Department of Pharmacology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.,F. J. and M. Sh. contributed equally to this work
| | - Sadaf Nezamoleslami
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Leila Moezi
- Department of Pharmacology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ahmad-Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Lei K, Yuan M, Zhou T, Ye Q, Zeng B, Zhou Q, Wei A, Guo L. Research progress in the application of bile acid-drug conjugates: A "trojan horse" strategy. Steroids 2021; 173:108879. [PMID: 34181976 DOI: 10.1016/j.steroids.2021.108879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 04/25/2021] [Accepted: 06/22/2021] [Indexed: 12/12/2022]
Abstract
Bile acid transporters are highly expressed in intestinal cells and hepatocytes, and they determine the uptake of drugs in cells by modulating cellular entry and exit. In order to improve the oral bioavailability of drugs and investigate the potential application prospects of drugs used to target cancer, numerous studies have adopted these transporters to identify prodrug strategies. Through the connection of covalent bonds between drugs and bile acids, the resulting bile acid-drug conjugates continue to be recognized as similar to natural unmodified bile acid and is translocated by the transporter. The present mini-review provides a brief summary of recent progress of the application of bile acid-drug conjugates based primarily on ASBT, NTCP, and OATP, with the hope of contributing to subsequent research.
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Affiliation(s)
- Kelu Lei
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Minghao Yuan
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Tao Zhou
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Qiang Ye
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Bin Zeng
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Qiang Zhou
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Ailing Wei
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Li Guo
- State Key Laboratory of Characteristic Chinese Medicine Resources in Southwest China, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
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Amzal R, Thébaut A, Lapalus M, Almes M, Grosse B, Mareux E, Collado-Hilly M, Davit-Spraul A, Bidou L, Namy O, Jacquemin E, Gonzales E. Pharmacological Premature Termination Codon Readthrough of ABCB11 in Bile Salt Export Pump Deficiency: An In Vitro Study. Hepatology 2021; 73:1449-1463. [PMID: 32702170 DOI: 10.1002/hep.31476] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 05/22/2020] [Accepted: 06/15/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a severe hepatocellular cholestasis due to biallelic mutations in ABCB11 encoding the canalicular bile salt export pump (BSEP). Nonsense mutations are responsible for the most severe phenotypes. The aim was to assess the ability of drugs to induce readthrough of six nonsense mutations (p.Y354X, p.R415X, p.R470X, p.R1057X, p.R1090X, and p.E1302X) identified in patients with PFIC2. APPROACH AND RESULTS The ability of G418, gentamicin, and PTC124 to induce readthrough was studied using a dual gene reporter system in NIH3T3 cells. The ability of gentamicin to induce readthrough and to lead to the expression of a full-length protein was studied in human embryonic kidney 293 (HEK293), HepG2, and Can 10 cells using immunodetection assays. The function of the gentamicin-induced full-length protein was studied by measuring the [3 H]-taurocholate transcellular transport in stable Madin-Darby canine kidney clones co-expressing Na+-taurocholate co-transporting polypeptide (Ntcp). Combinations of gentamicin and chaperone drugs (ursodeoxycholic acid, 4-phenylbutyrate [4-PB]) were investigated. In NIH3T3, aminoglycosides significantly increased the readthrough level of all mutations studied, while PTC124 only slightly increased the readthrough of p.E1302X. Gentamicin induced a readthrough of p.R415X, p.R470X, p.R1057X, and p.R1090X in HEK293 cells. The resulting full-length proteins localized within the cytoplasm, except for BsepR1090X , which was also detected at the plasma membrane of human embryonic kidney HEK293 and at the canalicular membrane of Can 10 and HepG2 cells. Additional treatment with 4-PB and ursodeoxycholic acid significantly increased the canalicular proportion of full-length BsepR1090X protein in Can 10 cells. In Madin-Darby canine kidney clones, gentamicin induced a 40% increase of the BsepR1090X [3 H]-taurocholate transport, which was further increased with additional 4-PB treatment. CONCLUSION This study constitutes a proof of concept for readthrough therapy in selected patients with PFIC2 with nonsense mutations.
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Affiliation(s)
- Rachida Amzal
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Alice Thébaut
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Martine Lapalus
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Marion Almes
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Brigitte Grosse
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Elodie Mareux
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Mauricette Collado-Hilly
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
| | - Anne Davit-Spraul
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Biochemistry Unit, Assistance Publique-Hôpitaux de Paris, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Laure Bidou
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif sur Yvette cedex, France
- Sorbonne Universités, Université Pierre et Marie Curie, UPMC, Paris, France
| | - Olivier Namy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif sur Yvette cedex, France
| | - Emmanuel Jacquemin
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Emmanuel Gonzales
- Université Paris-Saclay, Inserm, Physiopathogénèse et traitement des maladies du Foie, UMR_S 1193, Hepatinov, Orsay, France
- Pediatric Hepatology & Pediatric Liver Transplant Department, Centre de Référence de l'Atrésie des Voies Biliaires et des Cholestases Génétiques, Filière de Santé des Maladies Rares du Foie de l'enfant et de l'adulte, European Reference Network RARE-LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medecine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
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Ito S, Lee W, Park JE, Yasunaga M, Mori A, Ohtsuki S, Sugiyama Y. Transient, Tunable Expression of NTCP and BSEP in MDCKII Cells for Kinetic Delineation of the Rate-Determining Process and Inhibitory Effects of Rifampicin in Hepatobiliary Transport of Taurocholate. J Pharm Sci 2020; 110:365-375. [PMID: 33159914 DOI: 10.1016/j.xphs.2020.10.064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/14/2020] [Accepted: 10/30/2020] [Indexed: 11/16/2022]
Abstract
In predicting the hepatic elimination of compounds, the extended clearance concept has proven useful. Yet, its experimental proof was scarce partly due to the lack of models with the controlled expression of transporters. Here, the uptake and efflux transporters [NTCP (SLC10A1) and BSEP (ABCB11), respectively] were doubly and transiently expressed in MDCKII cells by electroporation-based transfection (with the BSEP plasmid amount varied and with the NTCP plasmid fixed), achieving the activity levels of NTCP and BSEP comparable to those of sandwich cultured human hepatocytes. The biliary excretion clearance for taurocholate increased proportionally to the BSEP expression level. Under the same conditions, the basal-to-apical transcellular clearance of taurocholate displayed an initial increase, and a subsequent plateau, indicating that the basolateral uptake of taurocholate became rate-limiting. The doubly transfected MDCKII cells were also used to kinetically analyze the inhibitory effects of rifampicin on BSEP and NTCP. The obtained results showed a bell-shaped profile for cell-to-medium concentration ratios over a range of rifampicin concentrations, which were quantitatively captured by kinetic modeling based on the extended clearance concept. The present study highlights the utility of the transient, tunable transporter expression system in delineating the rate-determining process and providing mechanistic insights into intracellular substrate accumulation.
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Affiliation(s)
- Sumito Ito
- GenoMembrane Co., Ltd, 2-3-18 Namamugi, Tsurumi-ku, Yokohama, Kanagawa 230-0052, Japan.
| | - Wooin Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji Eun Park
- Sugiyama Laboratory, RIKEN Baton Zone Program, RIKEN Cluster for Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; Pharmacokinetics, Dynamics and Metabolism, Translational Medicine and Early Development, R&D, Sanofi K.K., 3 Chome-20-2, Nishishinjuku, Tokyo 160-0023, Japan
| | - Masa Yasunaga
- GenoMembrane Co., Ltd, 2-3-18 Namamugi, Tsurumi-ku, Yokohama, Kanagawa 230-0052, Japan
| | - Ayano Mori
- Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Sumio Ohtsuki
- Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Yuichi Sugiyama
- Sugiyama Laboratory, RIKEN Baton Zone Program, RIKEN Cluster for Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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6
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Wang Y, Wilkerson M, Li J, Zhang W, Owens A, Wright S, Hidalgo I. Assessment of Statin Interactions With the Human NTCP Transporter Using a Novel Fluorescence Assay. Int J Toxicol 2020; 39:518-529. [PMID: 33078647 DOI: 10.1177/1091581820953066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Sodium taurocholate cotransporting polypeptide (NTCP), which is highly expressed in the sinusoidal membrane of hepatocytes, maintains bile acid homeostasis and participates in the hepatic disposition of a variety of endogenous substances as well as xenobiotics. Manifested by the involvement of organic anion-transporting polypeptides 1B1 and 1B3 (OATP1B1 and OATP1B3) in the hepatic uptake of statin drugs, sinusoidal membrane transporters play an important role in the pharmacokinetics and pharmacodynamics of these agents. It has been speculated that NTCP may function as an alternative pathway for statin hepatic uptake, complementary to OATP1B1 and OATP1B3. In the current study, we produced stable NTCP-expressing human embryonic kidney 293 (HEK293) cells and developed a fluorescence-based assay using flow cytometry for measuring NTCP transport with chenodeoxycholyl-(Nε-7-nitrobenz-2-oxa-1,3-diazole)-lysine (CDCA-NBD) as the substrate. NTCP-mediated CDCA-NBD transport was time-dependent and exhibited typical Michaelis-Menten kinetics, with a K m of 6.12 µM. Compounds known to interact with NTCP, including chenodeoxycholic acid and taurocholic acid, displayed concentration-dependent inhibition of NTCP-mediated CDCA-NBD transport. We report here a systematic evaluation of the interaction between statins and the NTCP transporter. Utilizing this system, several statins were either found to inhibit NTCP-dependent transport or act as substrates. We find a good correlation between the reported lipophilicity of statins and their ability to inhibit NTCP. The objective was to develop a higher-throughput system to evaluate potential inhibitors such as the statins. The in vitro assays using CDCA-NBD as fluorescent substrate are convenient, rapid, and have utility in screening drug candidates for potential drug-NTCP interactions.
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Affiliation(s)
- Ying Wang
- 376544Absorption Systems LP, Exton, PA, USA
| | | | - Jibin Li
- 376544Absorption Systems LP, Exton, PA, USA
| | - Wei Zhang
- 376544Absorption Systems LP, Exton, PA, USA
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7
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Mareux E, Lapalus M, Amzal R, Almes M, Aït-Slimane T, Delaunay JL, Adnot P, Collado-Hilly M, Davit-Spraul A, Falguières T, Callebaut I, Gonzales E, Jacquemin E. Functional rescue of an ABCB11 mutant by ivacaftor: A new targeted pharmacotherapy approach in bile salt export pump deficiency. Liver Int 2020; 40:1917-1925. [PMID: 32433800 DOI: 10.1111/liv.14518] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/22/2020] [Accepted: 05/13/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIM The canalicular bile salt export pump (BSEP/ABCB11) of hepatocytes is the main adenosine triphosphate (ATP)-binding cassette (ABC) transporter responsible for bile acid secretion. Mutations in ABCB11 cause several cholestatic diseases, including progressive familial intrahepatic cholestasis type 2 (PFIC2) often lethal in absence of liver transplantation. We investigated in vitro the effect and potential rescue of a BSEP mutation by ivacaftor, a clinically approved cystic fibrosis transmembrane conductance regulator (CFTR/ABCC7) potentiator. METHODS The p.T463I mutation, identified in a PFIC2 patient and located in a highly conserved ABC transporter motif, was studied by 3D structure modelling. The mutation was reproduced in a plasmid encoding a rat Bsep-green fluorescent protein. After transfection, mutant expression was studied in Can 10 cells. Taurocholate transport activity and ivacaftor effect were studied in Madin-Darby canine kidney (MDCK) clones co-expressing the rat sodium-taurocholate co-transporting polypeptide (Ntcp/Slc10A1). RESULTS As the wild-type protein, BsepT463I was normally targeted to the canalicular membrane of Can 10 cells. As predicted by 3D structure modelling, taurocholate transport activity was dramatically low in MDCK clones expressing BsepT463I . Ivacaftor treatment increased by 1.7-fold taurocholate transport activity of BsepT463I (P < .0001), reaching 95% of Bsepwt activity. These data suggest that the p.T463I mutation impairs ATP-binding, resulting in Bsep dysfunction that can be rescued by ivacaftor. CONCLUSION These results provide experimental evidence of ivacaftor therapeutic potential for selected patients with PFIC2 caused by ABCB11 missense mutations affecting BSEP function. This could represent a significant step forward for the care of patients with BSEP deficiency.
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Affiliation(s)
- Elodie Mareux
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France
| | - Martine Lapalus
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France
| | - Rachida Amzal
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France
| | - Marion Almes
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France.,Paediatric Hepatology & Paediatric Liver Transplant Department, Reference Center for Rare Paediatric Liver Diseases, FILFOIE, ERN RARE LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medicine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Tounsia Aït-Slimane
- Inserm, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Jean-Louis Delaunay
- Inserm, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, Paris, France
| | - Pauline Adnot
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France
| | - Mauricette Collado-Hilly
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France
| | - Anne Davit-Spraul
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France.,CHU Bicêtre, Biochemistry Unit, Assistance Publique-Hôpitaux de Paris, Le Kremlin-Bicêtre, France
| | - Thomas Falguières
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France
| | - Isabelle Callebaut
- Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie de Physique des Matériaux et de Cosmochimie, IMPMC, Sorbonne Université, Paris, France
| | - Emmanuel Gonzales
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France.,Paediatric Hepatology & Paediatric Liver Transplant Department, Reference Center for Rare Paediatric Liver Diseases, FILFOIE, ERN RARE LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medicine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
| | - Emmanuel Jacquemin
- Inserm, Physiopathogénèse et traitement des maladies du foie, UMR_S 1193, Hepatinov, Université Paris-Saclay, Orsay, France.,Paediatric Hepatology & Paediatric Liver Transplant Department, Reference Center for Rare Paediatric Liver Diseases, FILFOIE, ERN RARE LIVER, Assistance Publique-Hôpitaux de Paris, Faculty of Medicine Paris-Saclay, CHU Bicêtre, Le Kremlin-Bicêtre, France
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8
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Yang F, Takeuchi T, Tsuneyama K, Yokoi T, Oda S. Experimental Evidence of Liver Injury by BSEP-Inhibiting Drugs With a Bile Salt Supplementation in Rats. Toxicol Sci 2020; 170:95-108. [PMID: 30985903 DOI: 10.1093/toxsci/kfz088] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The bile salt export pump (BSEP, ABCB11) mediates bile acid efflux from hepatocytes into bile. Although the inhibition of BSEP has been implicated as an important mechanism of drug-induced liver injury (DILI), liver injury caused by BSEP-inhibiting drugs is rarely reproduced in experimental animals, probably due to species differences in bile acid composition between humans and rodents. In this study, we tested whether supplementation with chenodeoxycholic acid (CDCA) sodium, a hydrophobic bile salt, could sensitize rats to liver injury caused by a BSEP-inhibiting drug. A potent BSEP inhibitor, ketoconazole (KTZ), which is associated with clinical DILI, was intragastrically administered simultaneously with CDCA at a nontoxic dose once a day for 3 days. Plasma transaminase levels significantly increased in rats receiving CDCA+KTZ, whereas neither treatment with CDCA alone, KTZ alone nor a combination of CDCA and miconazole, a safe analog to KTZ, induced liver injury. In CDCA+KTZ-treated rats, most bile acid species in the liver significantly increased compared with treatment with vehicle or CDCA alone, suggesting that KTZ administration inhibited bile acid excretion. Furthermore, hepatic mRNA expression levels of a bile acid synthesis enzyme, Cyp7a1, and a basolateral bile salt influx transporter, Ntcp, decreased, whereas a canalicular phosphatidylcholine flippase, Mdr2, increased in the CDCA+KTZ group to compensate for hepatic bile acid accumulation. In conclusion, we found that oral CDCA supplementation predisposed rats to KTZ-induced liver injury due to the hepatic accumulation of bile acids. This method may be useful for assessing the potential of BSEP-inhibiting drugs inducing liver injury in vivo.
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Affiliation(s)
- Fuhua Yang
- Department of Drug Safety Sciences, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Taiki Takeuchi
- Department of Drug Safety Sciences, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Koichi Tsuneyama
- Department of Molecular and Environmental Pathology, Institute of Health Biosciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
| | - Tsuyoshi Yokoi
- Department of Drug Safety Sciences, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Shingo Oda
- Department of Drug Safety Sciences, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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9
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Deferm N, De Vocht T, Qi B, Van Brantegem P, Gijbels E, Vinken M, de Witte P, Bouillon T, Annaert P. Current insights in the complexities underlying drug-induced cholestasis. Crit Rev Toxicol 2019; 49:520-548. [PMID: 31589080 DOI: 10.1080/10408444.2019.1635081] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Drug-induced cholestasis (DIC) poses a major challenge to the pharmaceutical industry and regulatory agencies. It causes both drug attrition and post-approval withdrawal of drugs. DIC represents itself as an impaired secretion and flow of bile, leading to the pathological hepatic and/or systemic accumulation of bile acids (BAs) and their conjugate bile salts. Due to the high number of mechanisms underlying DIC, predicting a compound's cholestatic potential during early stages of drug development remains elusive. A profound understanding of the different molecular mechanisms of DIC is, therefore, of utmost importance. Although many knowledge gaps and caveats still exist, it is generally accepted that alterations of certain hepatobiliary membrane transporters and changes in hepatocellular morphology may cause DIC. Consequently, liver models, which represent most of these mechanisms, are valuable tools to predict human DIC. Some of these models, such as membrane-based in vitro models, are exceptionally well-suited to investigate specific mechanisms (i.e. transporter inhibition) of DIC, while others, such as liver slices, encompass all relevant biological processes and, therefore, offer a better representation of the in vivo situation. In the current review, we highlight the principal molecular mechanisms associated with DIC and offer an overview and critical appraisal of the different liver models that are currently being used to predict the cholestatic potential of drugs.
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Affiliation(s)
- Neel Deferm
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, Leuven, Belgium
| | - Tom De Vocht
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, Leuven, Belgium
| | - Bing Qi
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, Leuven, Belgium
| | - Pieter Van Brantegem
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, Leuven, Belgium
| | - Eva Gijbels
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Mathieu Vinken
- Entity of In Vitro Toxicology and Dermato-Cosmetology, Department of Pharmaceutical and Pharmacological Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Peter de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Thomas Bouillon
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, Leuven, Belgium
| | - Pieter Annaert
- Department of Pharmaceutical and Pharmacological Sciences, Drug Delivery and Disposition, KU Leuven, Leuven, Belgium
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10
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Yamaguchi H, Mano N. Analysis of membrane transport mechanisms of endogenous substrates using chromatographic techniques. Biomed Chromatogr 2019; 33:e4495. [PMID: 30661254 DOI: 10.1002/bmc.4495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/08/2019] [Accepted: 01/11/2019] [Indexed: 02/06/2023]
Abstract
Membrane transporters are expressed in various bodily tissues and play essential roles in the homeostasis of endogenous substances and the absortion, distribution and/or excretion of xenobiotics. For transporter assays, radioisotope-labeled compounds have been mainly used. However, commercially available radioisotope-labeled compounds are limited in number and relatively expensive. Chromatographic analyses such as high-performance liquid chromatography with ultraviolet absorptiometry and liquid chromatography with tandem mass spectrometry have also been applied for transport assays. To elucidate the transport properties of endogenous substrates, although there is no difficulty in performing assays using radioisotope-labeled probes, the endogenous background and the metabolism of the compound after its translocation across cell membranes must be considered when the intact compound is assayed. In this review, the current state of knowledge about the transport of endogenous substrates via membrane transporters as determined by chromatographic techniques is summarized. Chromatographic techniques have contributed to our understanding of the transport of endogenous substances including amino acids, catecholamines, bile acids, prostanoids and uremic toxins via membrane transporters.
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Affiliation(s)
- Hiroaki Yamaguchi
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan
| | - Nariyasu Mano
- Department of Pharmaceutical Sciences, Tohoku University Hospital, Sendai, Japan
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11
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Sequence-Based Analysis of Lipid-Related Metabolites in a Multiethnic Study. Genetics 2018; 209:607-616. [PMID: 29610217 DOI: 10.1534/genetics.118.300751] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/29/2018] [Indexed: 01/07/2023] Open
Abstract
Small molecule lipid-related metabolites are important components of fatty acid and steroid metabolism-two important contributors to human health. This study investigated the extent to which rare and common genetic variants spanning the human genome influence the lipid-related metabolome. Sequence data from 1552 European-Americans (EA) and 1872 African-Americans (AA) were analyzed to examine the impact of common and rare variants on the levels of 102 circulating lipid-related metabolites measured by a combination of chromatography and mass spectroscopy. We conducted single variant tests [minor allele frequency (MAF) > 5%, statistical significance P-value ≤ 2.45 × 10-10] and tests aggregating rare variants (MAF ≤ 5%) across multiple genomic motifs, such as coding regions and regulatory domains, and sliding windows. Multiethnic meta-analyses detected 53 lipid-related metabolites-locus pairs, which were inspected for evidence of consistent signal between the two ethnic groups. Thirty-eight lipid-related metabolite-genomic region associations were consistent across ethnicities, among which seven were novel. The regions contain genes that are related to metabolite transport (SLC10A1) and metabolism (SCD, FDX1, UGT2B15, and FADS2). Six of the seven novel findings lie in expression quantitative trait loci affecting the expression levels of 14 surrounding genes in multiple tissues. Imputed expression levels of 10 of the affected genes were associated with four corresponding lipid-related traits in at least one tissue. Our findings offer valuable insight into circulating lipid-related metabolite regulation in a multiethnic population.
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Asai A, Aihara E, Watson C, Mourya R, Mizuochi T, Shivakumar P, Phelan K, Mayhew C, Helmrath M, Takebe T, Wells J, Bezerra JA. Paracrine signals regulate human liver organoid maturation from induced pluripotent stem cells. Development 2017; 144:1056-1064. [PMID: 28275009 DOI: 10.1242/dev.142794] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 02/01/2017] [Indexed: 12/17/2022]
Abstract
A self-organizing organoid model provides a new approach to study the mechanism of human liver organogenesis. Previous animal models documented that simultaneous paracrine signaling and cell-to-cell surface contact regulate hepatocyte differentiation. To dissect the relative contributions of the paracrine effects, we first established a liver organoid using human induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as previously reported. Time-lapse imaging showed that hepatic-specified endoderm iPSCs (HE-iPSCs) self-assembled into three-dimensional organoids, resulting in hepatic gene induction. Progressive differentiation was demonstrated by hepatic protein production after in vivo organoid transplantation. To assess the paracrine contributions, we employed a Transwell system in which HE-iPSCs were separately co-cultured with MSCs and/or HUVECs. Although the three-dimensional structure did not form, their soluble factors induced a hepatocyte-like phenotype in HE-iPSCs, resulting in the expression of bile salt export pump. In conclusion, the mesoderm-derived paracrine signals promote hepatocyte maturation in liver organoids, but organoid self-organization requires cell-to-cell surface contact. Our in vitro model demonstrates a novel approach to identify developmental paracrine signals regulating the differentiation of human hepatocytes.
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Affiliation(s)
- Akihiro Asai
- Pediatric Liver Care Center, Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Eitaro Aihara
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Carey Watson
- Division of Pediatric Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Reena Mourya
- Pediatric Liver Care Center, Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Tatsuki Mizuochi
- Pediatric Liver Care Center, Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Pranavkumar Shivakumar
- Pediatric Liver Care Center, Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Kieran Phelan
- Pediatric Liver Care Center, Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Christopher Mayhew
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Michael Helmrath
- Division of Pediatric Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Takanori Takebe
- Department of Regenerative Medicine, Yokohama City University, Yokohama, Kanagawa 236-0004, Japan
| | - James Wells
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Jorge A Bezerra
- Pediatric Liver Care Center, Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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Oizumi K, Sekine S, Fukagai M, Susukida T, Ito K. Identification of Bile Acids Responsible for Inhibiting the Bile Salt Export Pump, Leading to Bile Acid Accumulation and Cell Toxicity in Rat Hepatocytes. J Pharm Sci 2017; 106:2412-2419. [DOI: 10.1016/j.xphs.2017.05.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 01/29/2023]
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Shen ZW, Luo MY, Hu HH, Zhou H, Jiang HD, Yu LS, Zeng S. Screening and verifying potential NTCP inhibitors from herbal medicinal ingredients using the LLC-PK1 cell model stably expressing human NTCP. Chin J Nat Med 2017; 14:549-60. [PMID: 27507206 DOI: 10.1016/s1875-5364(16)30065-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Indexed: 12/13/2022]
Abstract
NTCP is specifically expressed on the basolateral membrane of hepatocytes, participating in the enterohepatic circulation of bile salts, especially conjugated bile salts, to maintain bile salts homeostasis. In addition, recent studies have found that NTCP is a functional receptor of HBV and HDV. Therefore, it is important to study the interaction between drugs and NTCP and identify the inhibitors/substrates of NTCP. In the present study, a LLC-PK1 cell model stably expressing human NTCP was established, which was simple and suitable for high throughput screening, and utilized to screen and verify the potential inhibitors of NTCP from 102 herbal medicinal ingredients. The results showed that ginkgolic acid (GA) (13 : 0), GA (15 : 1), GA (17 : 1), erythrosine B, silibinin, and emodin have inhibitory effects on NTCP uptake of TCNa in a concentration-dependent manner. Among them, GA (13 : 0) and GA (15 : 1) exhibited the stronger inhibitory effects, with IC50 values being less than 8.3 and 13.5 μmol·L(-1), respectively, than the classical inhibitor, cyclosporin A (CsA) (IC50 = 20.33 μmol·L(-1)). Further research demonstrated that GA (13 : 0), GA (15 : 1), GA (17 : 1), silibinin, and emodin were not substrates of NTCP. These findings might contribute to a better understanding of the disposition of the herbal ingredients in vivo, especially in biliary excretion.
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Affiliation(s)
- Zhuo-Wei Shen
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Meng-Yue Luo
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hai-Hong Hu
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hui Zhou
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hui-Di Jiang
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Lu-Shan Yu
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | - Su Zeng
- Institute of Drug Metabolism and Pharmaceutical Analysis, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China.
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15
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Assays for Analyzing the Role of Transport Proteins in the Uptake and the Vectorial Transport of Substances Affecting Cell Viability. Methods Mol Biol 2017; 1601:123-135. [PMID: 28470523 DOI: 10.1007/978-1-4939-6960-9_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endogenous compounds, drugs, or other xenobiotics may affect cell viability. A prerequisite for intracellular cell damage is the uptake of such substances across the plasma membrane into cells. Furthermore, the subsequent transporter-mediated export out of cells may influence cell viability. Therefore, transport proteins mediating the uptake (uptake transporter) or export (export pumps) of substances in and out of cells are important determinants of cell viability. Uptake transporters mostly belong to the superfamily of solute carriers (SLC transporters), whereas export pumps are members of the ABC-transporter superfamily (ATP-binding cassette). Cell systems recombinantly overexpressing uptake transporters (single transfectants) or multiple-transfected cell models expressing simultaneously an uptake transporter together with an export pump (double transfectants) are important in vitro tools for analyzing protein-mediated transport of potentially cell toxic compounds.Here we describe different in vitro transport assays for the functional analysis of transport proteins. Using single-transfected HEK293 cells stably overexpressing an uptake transporter, substances can be tested as potential substrates (uptake assay) or potential transport inhibitors (inhibition assay) for the respective transport protein. Vectorial transport of substances with the uptake across the basolateral plasma membrane and the export across the apical membrane of polarized grown MDCKII cells can be analyzed using double-transfected cell models with the simultaneous overexpression of an uptake transport and an export pump in vectorial transport assays, thereby mimicking physiological transport processes, e.g., in liver or kidney.
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16
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Schupp AK, Trilling M, Rattay S, Le-Trilling VTK, Haselow K, Stindt J, Zimmermann A, Häussinger D, Hengel H, Graf D. Bile Acids Act as Soluble Host Restriction Factors Limiting Cytomegalovirus Replication in Hepatocytes. J Virol 2016; 90:6686-6698. [PMID: 27170759 PMCID: PMC4944301 DOI: 10.1128/jvi.00299-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/06/2016] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED The liver constitutes a prime site of cytomegalovirus (CMV) replication and latency. Hepatocytes produce, secrete, and recycle a chemically diverse set of bile acids, with the result that interactions between bile acids and cytomegalovirus inevitably occur. Here we determined the impact of naturally occurring bile acids on mouse CMV (MCMV) replication. In primary mouse hepatocytes, physiological concentrations of taurochenodeoxycholic acid (TCDC), glycochenodeoxycholic acid, and to a lesser extent taurocholic acid significantly reduced MCMV-induced gene expression and diminished the generation of virus progeny, while several other bile acids did not exert antiviral effects. The anticytomegalovirus activity required active import of bile acids via the sodium-taurocholate-cotransporting polypeptide (NTCP) and was consistently observed in hepatocytes but not in fibroblasts. Under conditions in which alpha interferon (IFN-α) lacks antiviral activity, physiological TCDC concentrations were similarly effective as IFN-γ. A detailed investigation of distinct steps of the viral life cycle revealed that TCDC deregulates viral transcription and diminishes global translation in infected cells. IMPORTANCE Cytomegaloviruses are members of the Betaherpesvirinae subfamily. Primary infection leads to latency, from which cytomegaloviruses can reactivate under immunocompromised conditions and cause severe disease manifestations, including hepatitis. The present study describes an unanticipated antiviral activity of conjugated bile acids on MCMV replication in hepatocytes. Bile acids negatively influence viral transcription and exhibit a global effect on translation. Our data identify bile acids as site-specific soluble host restriction factors against MCMV, which may allow rational design of anticytomegalovirus drugs using bile acids as lead compounds.
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Affiliation(s)
- Anna-Kathrin Schupp
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Mirko Trilling
- Institute for Virology, Heinrich-Heine-University, Düsseldorf, Germany
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stephanie Rattay
- Institute for Virology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Vu Thuy Khanh Le-Trilling
- Institute for Virology, Heinrich-Heine-University, Düsseldorf, Germany
- Institute for Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Katrin Haselow
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jan Stindt
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Albert Zimmermann
- Institute for Virology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
| | - Hartmut Hengel
- Institute for Virology, Heinrich-Heine-University, Düsseldorf, Germany
- Department for Medical Microbiology and Hygiene, Institute of Virology, Albert-Ludwigs-University, Freiburg, Germany
| | - Dirk Graf
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University, Düsseldorf, Germany
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Akita H, Fujiwara T, Santiwarangkool S, Hossen N, Kajimoto K, El-Sayed A, Tabata Y, Harashima H. Transcytosis-Targeting Peptide: A Conductor of Liposomal Nanoparticles through the Endothelial Cell Barrier. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:1212-1221. [PMID: 26426116 DOI: 10.1002/smll.201500909] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 07/19/2015] [Indexed: 06/05/2023]
Abstract
The ultimate goal in the area of drug-delivery systems is the development of a nanoparticle that can penetrate the endothelial cell monolayer for the targeting of tissue parenchyma. In the present study, we identify a transcytosis-targeting peptide (TTP) that permits polyethyleneglycol (PEG)-modified liposomes (PEG-LPs) to penetrate through monolayers of brain-derived endothelial cells. These endothelial cells were layered on a gelatin nanofiber sheet, a nanofiber meshwork that allows the evaluation of transcellular transport of nanosized particles (ca. 100 nm). Systematic modification of the sequences results in the identification of the consensus sequence of TTP as L(R/K)QZZZL, where Z denotes hydrophilic amino acids (R/K/S and partially D). The TTP-modified liposomes are bound on the heparin sulfate proteoglycan, and are then taken up via lipid raft-mediated endocytosis. Subsequent intracellular imaging of the particles reveals a unique intracellular sorting of TTP-modified PEG liposomes (TTP-PEG-LPs); namely the TTP-LPs are not localized with the lysosomes, whereas this co-localization is dominant in the unmodified PEG liposomes (PEG-LPs). The in vivo endothelial penetration of liposomes in adipose tissue is conferred by the dual modification of the particles with TTP and tissue-targeting ligands. This technology promises innovations in intravenously available delivery system to tissue parenchyma.
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Affiliation(s)
- Hidetaka Akita
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
| | - Takahiro Fujiwara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
| | - Sarochin Santiwarangkool
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
| | - Nazir Hossen
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
| | - Kazuaki Kajimoto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
| | - Ayman El-Sayed
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
| | - Yasuhiko Tabata
- Institute for Frontier Medical Sciences, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hideyoshi Harashima
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita12 Nishi6, Kita-ku, Sapporo City, Hokkaido, 060-0812, Japan
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Kubitz R, Dröge C, Kluge S, Stindt J, Häussinger D. Genetic variations of bile salt transporters. DRUG DISCOVERY TODAY. TECHNOLOGIES 2015; 12:e55-67. [PMID: 25027376 DOI: 10.1016/j.ddtec.2014.03.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bile salt transporters directly or indirectly influence biological processes through physicochemical or signalling properties of bile salts. The coordinated action of uptake and efflux transporters in polarized epithelial cells of the liver, biliary tree, small intestine and kidney determine bile salt concentrations in different compartments of the body. Genetic variations of bile salt transporters lead to clinical relevant phenotypes of varying severity ranging from a predisposition for drug-induced liver injury to rapidly progressing end-stage liver disease. This review focuses on the impact of genetic variations of bile salt transporters including BSEP, NTCP, ASBT and OSTα/β and discusses approaches for transporter analysis.
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19
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Dong Z, Ekins S, Polli JE. A substrate pharmacophore for the human sodium taurocholate co-transporting polypeptide. Int J Pharm 2014; 478:88-95. [PMID: 25448570 DOI: 10.1016/j.ijpharm.2014.11.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/14/2014] [Accepted: 11/12/2014] [Indexed: 01/05/2023]
Abstract
Human sodium taurocholate co-transporting polypeptide (NTCP) is the main bile acid uptake transporter in the liver with the capability to translocate xenobiotics. While its inhibitor requirements have been recently characterized, its substrate requirements have not. The objectives of this study were (a) to elucidate NTCP substrate requirements using native bile acids and bile acid analogs, (b) to develop the first pharmacophore for NTCP substrates and compare it with the inhibitor pharmacophores, and (c) to identify additional NTCP novel substrates. Thus, 18 native bile acids and two bile acid conjugates were initially assessed for NTCP inhibition and/or uptake, which suggested a role of hydroxyl pattern and steric interaction in NTCP binding and translocation. A common feature pharmacophore for NTCP substrate uptake was developed, using 14 native bile acids and bile acid conjugates, yielding a model which featured three hydrophobes, one hydrogen bond donor, one negative ionizable feature and three excluded volumes. This model was used to search a database of FDA approved drugs and retrieved the majority of the known NTCP substrates. Among the retrieved drugs, irbesartan and losartan were identified as novel NTCP substrates, suggesting a potential role of NTCP in drug disposition.
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Affiliation(s)
- Zhongqi Dong
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, 20 Penn Street, Baltimore, Maryland 21201, USA
| | - Sean Ekins
- Collaborations in Chemistry, 5616 Hilltop Needmore Road, Fuquay Varina, NC 27526, USA
| | - James E Polli
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, 20 Penn Street, Baltimore, Maryland 21201, USA.
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20
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Vellonen KS, Malinen M, Mannermaa E, Subrizi A, Toropainen E, Lou YR, Kidron H, Yliperttula M, Urtti A. A critical assessment of in vitro tissue models for ADME and drug delivery. J Control Release 2014; 190:94-114. [DOI: 10.1016/j.jconrel.2014.06.044] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/22/2014] [Accepted: 06/23/2014] [Indexed: 12/22/2022]
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de Lima Toccafondo Vieira M, Tagliati CA. Hepatobiliary transporters in drug-induced cholestasis: a perspective on the current identifying tools. Expert Opin Drug Metab Toxicol 2014; 10:581-97. [PMID: 24588537 DOI: 10.1517/17425255.2014.884069] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Impaired bile formation leads to the accumulation of cytotoxic bile salts in hepatocytes and, consequently, cholestasis and severe liver disease. Knowledge of the role of hepatobiliary transporters, especially the bile salt export pump (BSEP), in the pathogenesis of cholestasis is continuously increasing. AREAS COVERED This review provides an introduction into the role of these transport proteins in bile formation. It addresses the clinical relevance and pathophysiologic consequences of altered functions of these transporters by genetic mutations and drugs. In particular, the current practical aspects of identification and mitigation of drug candidates with liver liabilities employed during drug development, with an emphasis on preclinical screening for BSEP interaction, are discussed. EXPERT OPINION Within the potential pathogenetic mechanisms of acquired cholestasis, the inhibition of BSEP by drugs is well established. Interference of a new compound with BSEP transport activity should raise a warning sign to conduct follow-up experiments and to monitor liver function during clinical development. A combination of in vitro screening for transport interaction, in silico predicting models, and consideration of physicochemical and metabolic properties should lead to a more efficient screening of potential liver liability.
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Affiliation(s)
- Manuela de Lima Toccafondo Vieira
- Faculdade de Farmácia - UFMG, Departamento de Análises Clínicas e Toxicológicas, Av. Antônio Carlos, 6.627 - Pampulha, 31270-901 - Belo Horizonte - MG , Brazil +55 31 3547 3462 ;
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Reshetnyak VI. Physiological and molecular biochemical mechanisms of bile formation. World J Gastroenterol 2013; 19:7341-7360. [PMID: 24259965 PMCID: PMC3831216 DOI: 10.3748/wjg.v19.i42.7341] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 07/17/2013] [Accepted: 09/29/2013] [Indexed: 02/06/2023] Open
Abstract
This review considers the physiological and molecular biochemical mechanisms of bile formation. The composition of bile and structure of a bile canaliculus, biosynthesis and conjugation of bile acids, bile phospholipids, formation of bile micellar structures, and enterohepatic circulation of bile acids are described. In general, the review focuses on the molecular physiology of the transporting systems of the hepatocyte sinusoidal and apical membranes. Knowledge of physiological and biochemical basis of bile formation has implications for understanding the mechanisms of development of pathological processes, associated with diseases of the liver and biliary tract.
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23
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Herédi-Szabó K, Kis E, Krajcsi P. The vesicular transport assay: validated in vitro methods to study drug-mediated inhibition of canalicular efflux transporters ABCB11/BSEP and ABCC2/MRP2. ACTA ACUST UNITED AC 2013; Chapter 23:Unit 23.4. [PMID: 23169269 DOI: 10.1002/0471140856.tx2304s54] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The canalicular membrane of hepatocytes contains several transport proteins that use the energy of ATP to efflux potentially toxic molecules to the bile. Probably the two most important proteins at this location are MRP2 and BSEP, which transport phase II conjugates of xenobiotics and endobiotics and conjugated bile salts, respectively. The impaired function of either of these transporter proteins reduces the clearance of the toxic conjugates, resulting in their accumulation in the hepatocytes and eventually the plasma. Conjugated bile salts and phase II metabolites are compounds with low passive permeability; therefore, the most commonly used test system to investigate MRP2- and BSEP-mediated transport processes is the vesicular transport assay. The concentration of probe substrates and inhibitors used in the experiment is close to their free concentration in the hepatocytes, providing an advantage when calculating kinetic parameters (K(m), K(i), V(max)). The protocols aim to assist scientists to set up a transport assay for a known or potential substrate and test small molecule inhibition of the transporters.
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van Staden CJ, Morgan RE, Ramachandran B, Chen Y, Lee PH, Hamadeh HK. Membrane vesicle ABC transporter assays for drug safety assessment. ACTA ACUST UNITED AC 2013; Chapter 23:Unit 23.5. [PMID: 23169270 DOI: 10.1002/0471140856.tx2305s54] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The use of plasma membrane vesicles that overexpress the bile salt export pump (BSEP) or multidrug resistance-associated protein 2, 3, or 4 (MRP2-4) with an in vitro vacuum filtration system offers a rapid and reliable means for screening drug candidates for their effects on transporter function in hepatocytes and thus their potential for causing drug-induced liver injury (DILI). Comparison of transporter activity in the presence and absence of ATP allows for determination of a specific assay window for each transporter. This window is used to determine the degree to which each test compound inhibits transporter activity. This assay battery is helpful for prioritizing and rank-ordering compounds within a chemical series with respect to each other and in the context of known inhibitors of transporter activity and/or liver injury. This model can be used to influence the drug development process at an early stage and provide rapid feedback regarding the selection of compounds for advancement to in vivo safety evaluations. A detailed protocol for the high-throughput assessment of ABC transporter function is provided, including specific recommendations for curve-fitting to help ensure consistent results.
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Kis E, Ioja E, Rajnai Z, Jani M, Méhn D, Herédi-Szabó K, Krajcsi P. BSEP inhibition: in vitro screens to assess cholestatic potential of drugs. Toxicol In Vitro 2011; 26:1294-9. [PMID: 22120137 DOI: 10.1016/j.tiv.2011.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 10/26/2011] [Accepted: 11/09/2011] [Indexed: 12/17/2022]
Abstract
Bile salt export pump (BSEP, ABC11) is a membrane protein that is localized in the cholesterol-rich canalicular membrane of hepatocytes. Its function is to eliminate unconjugated and conjugated bile acids/salts from hepatocyte into the bile. In humans there is no compensatory mechanism for the loss of this transporter. Mutations of BSEP result in a genetic disease, called progressive familial intrahepatic cholestasis type 2 (PFIC2), that is characterized with decreased biliary bile salt secretion, leading to decreased bile flow and accumulation of bile salts inside the hepatocyte, inflicting damage. BSEP inhibitor drugs produce similar bile salt retention that may lead to severe cholestasis and liver damage. Drug-induced liver injury is a relevant clinical issue, in severe cases ending in liver transplantation. Therefore, measurement of BSEP inhibition by candidate drugs has high importance in drug discovery and development. Although several methods are suitable to detect BSEP-drug interactions, due to interspecies differences in bile acid composition, differences in hepatobiliary transporter modulation, they have limitations. This review summarizes appropriate in vitro methods that could be able to predict BSEP-drug candidate interactions in humans before the start of clinical phases.
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26
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Stieger B. The role of the sodium-taurocholate cotransporting polypeptide (NTCP) and of the bile salt export pump (BSEP) in physiology and pathophysiology of bile formation. Handb Exp Pharmacol 2011:205-59. [PMID: 21103971 DOI: 10.1007/978-3-642-14541-4_5] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bile formation is an important function of the liver. Bile salts are a major constituent of bile and are secreted by hepatocytes into bile and delivered into the small intestine, where they assist in fat digestion. In the small intestine, bile salts are almost quantitatively reclaimed and transported back via the portal circulation to the liver. In the liver, hepatocytes take up bile salts and secrete them again into bile for ongoing enterohepatic circulation. Uptake of bile salts into hepatocytes occurs largely in a sodium-dependent manner by the sodium taurocholate cotransporting polypeptide NTCP. The transport properties of NTCP have been extensively characterized. It is an electrogenic member of the solute carrier family of transporters (SLC10A1) and transports predominantly bile salts and sulfated compounds, but is also able to mediate transport of additional substrates, such as thyroid hormones, drugs and toxins. It is highly regulated under physiologic and pathophysiologic conditions. Regulation of NTCP copes with changes of bile salt load to hepatocytes and prevents entry of cytotoxic bile salts during liver disease. Canalicular export of bile salts is mediated by the ATP-binding cassette transporter bile salt export pump BSEP (ABCB11). BSEP constitutes the rate limiting step of hepatocellular bile salt transport and drives enterohepatic circulation of bile salts. It is extensively regulated to keep intracellular bile salt levels low under normal and pathophysiologic situations. Mutations in the BSEP gene lead to severe progressive familial intrahepatic cholestasis. The substrates of BSEP are practically restricted to bile salts and their metabolites. It is, however, subject to inhibition by endogenous metabolites or by drugs. A sustained inhibition will lead to acquired cholestasis, which can end in liver injury.
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Affiliation(s)
- Bruno Stieger
- Division of Clinical Pharmacology and Toxicology, University Hospital, 8091, Zurich, Switzerland.
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Yoshikado T, Takada T, Yamamoto T, Yamaji H, Ito K, Santa T, Yokota H, Yatomi Y, Yoshida H, Goto J, Tsuji S, Suzuki H. Itraconazole-induced cholestasis: involvement of the inhibition of bile canalicular phospholipid translocator MDR3/ABCB4. Mol Pharmacol 2010; 79:241-50. [PMID: 21056966 DOI: 10.1124/mol.110.067256] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Biliary secretion of bile acids and phospholipids, both of which are essential components of biliary micelles, are mediated by the bile salt export pump (BSEP/ABCB11) and multidrug resistance 3 P-glycoprotein (MDR3/ABCB4), respectively, and their genetic dysfunction leads to the acquisition of severe cholestatic diseases. In the present study, we found two patients with itraconazole (ITZ)-induced cholestatic liver injury with markedly high serum ITZ concentrations. To characterize the effect of ITZ on bile formation in vivo, biliary bile acids and phospholipids were analyzed in ITZ-treated rats, and it was revealed that biliary phospholipids, rather than bile acids, were drastically reduced in the presence of clinically relevant concentrations of ITZ. Moreover, by using MDR3-expressing LLC-PK1 cells, we found that MDR3-mediated efflux of [¹⁴C]phosphatidylcholine was significantly reduced by ITZ. In contrast, BSEP-mediated transport of [³H]taurocholate was not significantly affected by ITZ, which is consistent with our in vivo observations. In conclusion, this study suggests the involvement of the inhibition of MDR3-mediated biliary phospholipids secretion in ITZ-induced cholestasis. Our approach may be useful for analyzing mechanisms of drug-induced cholestasis and evaluating the cholestatic potential of clinically used drugs and drug candidates.
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Affiliation(s)
- Takashi Yoshikado
- Department of Pharmacy, University of Tokyo Hospital, Faculty of Medicine, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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Abstract
Generation of bile is a key function of the liver. Its impairment leads to accumulation of cytotoxic bile salts in hepatocytes and, consequently, to liver disease. The bile salt export pump, BSEP, is critically involved in the secretion of bile salts into bile. Its function can be disturbed or abolished by inherited mutations. This will lead to progressive intrahepatic cholestais and severe liver disease. In addition to mutations, BSEP can be inhibited by acquired factors, such as xenobiotics or drugs, aberrant bile salt metabolites, or pregnancy. This inhibition will lead to acquired cholestasis. Some drugs are now known to be competitive inhibitors of Bsep. In addition, a polymorphism in the gene coding for BSEP has been identified as a potential susceptibility factor for acquired cholestasis.
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29
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Morgan RE, Trauner M, van Staden CJ, Lee PH, Ramachandran B, Eschenberg M, Afshari CA, Qualls CW, Lightfoot-Dunn R, Hamadeh HK. Interference with bile salt export pump function is a susceptibility factor for human liver injury in drug development. Toxicol Sci 2010; 118:485-500. [PMID: 20829430 DOI: 10.1093/toxsci/kfq269] [Citation(s) in RCA: 240] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The bile salt export pump (BSEP) is an efflux transporter, driving the elimination of endobiotic and xenobiotic substrates from hepatocytes into the bile. More specifically, it is responsible for the elimination of monovalent, conjugated bile salts, with little or no assistance from other apical transporters. Disruption of BSEP activity through genetic disorders is known to manifest in clinical liver injury such as progressive familial intrahepatic cholestasis type 2. Drug-induced disruption of BSEP is hypothesized to play a role in the development of liver injury for several marketed or withdrawn therapeutics. Unfortunately, preclinical animal models have been poor predictors of the liver injury associated with BSEP interference observed for humans, possibly because of interspecies differences in bile acid composition, differences in hepatobiliary transporter modulation or constitutive expression, as well as other mechanisms. Thus, a BSEP-mediated liver liability may go undetected until the later stages of drug development, such as during clinical trials or even postlicensing. In the absence of a relevant preclinical test system for BSEP-mediated liver injury, the toxicological relevance of available in vitro models to human health rely on the use of benchmark compounds with known clinical outcomes, such as marketed or withdrawn drugs. In this study, membrane vesicles harvested from BSEP-transfected insect cells were used to assess the activity of more than 200 benchmark compounds to thoroughly investigate the relationship between interference with BSEP function and liver injury. The data suggest a relatively strong association between the pharmacological interference with BSEP function and human hepatotoxicity. Although the most accurate translation of risk would incorporate pharmacological potency, pharmacokinetics, clearance mechanisms, tissue distribution, physicochemical properties, indication, and other drug attributes, the additional understanding of a compound's potency for BSEP interference should help to limit or avoid BSEP-related liver liabilities in humans that are not often detected by standard preclinical animal models.
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Affiliation(s)
- Ryan E Morgan
- Department of Comparative Biology and Safety Sciences Amgen Inc., Thousand Oaks, California 91320, USA
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30
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Abstract
In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na(+) taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OSTalpha-OSTbeta. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers.
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Affiliation(s)
- Paul A Dawson
- Department of Internal Medicine and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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31
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Abstract
In liver and intestine, transporters play a critical role in maintaining the enterohepatic circulation and bile acid homeostasis. Over the past two decades, there has been significant progress toward identifying the individual membrane transporters and unraveling their complex regulation. In the liver, bile acids are efficiently transported across the sinusoidal membrane by the Na(+) taurocholate cotransporting polypeptide with assistance by members of the organic anion transporting polypeptide family. The bile acids are then secreted in an ATP-dependent fashion across the canalicular membrane by the bile salt export pump. Following their movement with bile into the lumen of the small intestine, bile acids are almost quantitatively reclaimed in the ileum by the apical sodium-dependent bile acid transporter. The bile acids are shuttled across the enterocyte to the basolateral membrane and effluxed into the portal circulation by the recently indentified heteromeric organic solute transporter, OSTalpha-OSTbeta. In addition to the hepatocyte and enterocyte, subgroups of these bile acid transporters are expressed by the biliary, renal, and colonic epithelium where they contribute to maintaining bile acid homeostasis and play important cytoprotective roles. This article will review our current understanding of the physiological role and regulation of these important carriers.
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Affiliation(s)
- Paul A Dawson
- Department of Internal Medicine and Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Shao J, Nangaku M, Inagi R, Kato H, Miyata T, Matsusaka T, Noiri E, Fujita T. Receptor-independent intracellular radical scavenging activity of an angiotensin II receptor blocker. J Hypertens 2007; 25:1643-9. [PMID: 17620961 DOI: 10.1097/hjh.0b013e328165d159] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVES Angiotensin II plays a crucial role in the induction of oxidative stress and the pathogenesis of cardiovascular and renal diseases, and the beneficial mechanisms of angiotensin II receptor 1 blockers (ARBs) are multifactorial. We investigated the receptor-independent protective role of an ARB using primary-cultured mesangial cells from angiotensin II receptor 1 knockout or wild-type mice and a highly lipophilic ARB, telmisartan. METHODS AND RESULTS Intracellular reactive oxygen species were estimated using a fluorogenic probe, CM-H2DCFDA. Non-angiotensin II-induced reactive oxygen species production was generated by exposing cells to hydrogen peroxide alone or after treatment with telmisartan. Flow cytometry analysis showed that angiotensin II induced an increase in oxidant production in a dose-dependent manner in wild-type cells, but not in knockout cells. In contrast, hydrogen peroxide induced oxidative stress in both wild-type and knockout cells. Interestingly, telmisartan attenuated the oxidative stress induced by hydrogen peroxide in both cells, suggesting that it acted via a receptor-independent antioxidant effect. Intracellular concentrations of telmisartan were confirmed by high-performance liquid chromatography analysis. Expression of plasminogen activator inhibitor 1, which is stimulated by oxidative stress, was also attenuated by telmisartan in a receptor-independent as well as receptor-dependent manner. Telmisartan did not change expression levels of antioxidative enzymes such as catalase or glutathione peroxidase. Furthermore, the amelioration of oxidative stress by telmisartan did not involve the peroxisome proliferator-activated receptor-gamma pathway. CONCLUSIONS Telmisartan inhibits intracellular oxidative stress, at least in part, in a receptor-independent manner, possibly owing to its lipophilic and antioxidant structure.
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Affiliation(s)
- Jing Shao
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
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Hayashi H, Sugiyama Y. 4-phenylbutyrate enhances the cell surface expression and the transport capacity of wild-type and mutated bile salt export pumps. Hepatology 2007; 45:1506-16. [PMID: 17538928 DOI: 10.1002/hep.21630] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
UNLABELLED Progressive familial intrahepatic cholestasis type 2 (PFIC2) is caused by a mutation in the bile salt export pump (BSEP/ABCB11) gene. We previously reported that E297G and D482G BSEP, which are frequently found mutations in European patients, result in impaired membrane trafficking, whereas both mutants retain their transport function. The dysfunctional localization is probably attributable to the retention of BSEP in endoplasmic reticulum (ER) followed by proteasomal degradation. Because sodium 4-phenylbutyrate (4PBA) has been shown to restore the reduced cell surface expression of mutated plasma membrane proteins, in the current study, we investigated the effect of 4PBA treatment on E297G and D482G BSEP. Transcellular transport and cell surface biotinylation studies using Madin-Darby canine kidney (MDCK) II cells demonstrated that 4PBA treatment increased functional cell surface expression of wild-type (WT), E297G, and D482G BSEP. The prolonged half-life of cell surface-resident BSEP with 4PBA treatment was responsible for this result. Moreover, treatment of Sprague-Dawley rats with 4PBA resulted in an increase in BSEP expression at the canalicular membrane, which was accompanied by an increase in the biliary excretion of [(3)H]taurocholic acid (TC). CONCLUSION 4PBA treatment with a clinically achievable concentration enhances the cell surface expression and the transport capacity of WT, E297G, and D482G BSEP in MDCK II cells, and also induces functional BSEP expression at the canalicular membrane and bile acid transport via canalicular membrane in vivo. 4PBA is a potential pharmacological agent for treating not only PFIC2 patients with E297G and D482G mutations but also other cholestatic patients, in whom the BSEP expression at the canalicular membrane is reduced.
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Affiliation(s)
- Hisamitsu Hayashi
- Department of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Liu L, Pang KS. An integrated approach to model hepatic drug clearance. Eur J Pharm Sci 2006; 29:215-30. [PMID: 16806855 DOI: 10.1016/j.ejps.2006.05.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 05/16/2006] [Indexed: 11/15/2022]
Abstract
It has been well accepted that hepatic drug extraction depends on the blood flow, vascular binding, transmembrane barriers, transporters, enzymes and cosubstrate and their zonal heterogeneity. Models of hepatic drug clearances have been appraised with respect to their utility in predicting drug removal by the liver. Among these models, the "well-stirred" model is the simplest since it assumes venous equilibration, with drug emerging from the outflow being in equilibrium with drug within the liver, and the concentration is the same throughout. The "parallel tube" and dispersion models, and distributed model of Goresky and co-workers have been used to account for the observed sinusoidal concentration gradient from the inlet and outlet. Departure from these models exists to include heterogeneity in flow, enzymes, and transporters. This article utilized the physiologically based pharmacokinetic (PBPK) liver model and its extension that include heterogeneity in enzymes and transporters to illustrate how in vitro uptake and metabolic data from zonal hepatocytes on transport and enzymes may be used to predict the kinetics of removal in the intact liver; binding data were also necessary. In doing so, an integrative platform was provided to examine determinants of hepatic drug clearance. We used enalapril and digoxin as examples, and described a simple liver PBPK model that included transmembrane transport and metabolism occurring behind the membrane, and a zonal model in which the PBPK model was expanded three sets of sub-compartments that are arranged sequentially to represent zones 1, 2, and 3 along the flow path. The latter model readily accommodated the heterogeneous distribution of hepatic enzymes and transporters. Transport and metabolic data, piecewise information that served as initial estimates, allowed for the unknown efflux and other intrinsic clearances to be estimated. The simple or zonal PBPK model provides predictive views on the hepatic removal of drugs and metabolites.
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Affiliation(s)
- Lichuan Liu
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 19 Russell Street, Toronto, Ontario, Canada M5S 2S2
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35
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Hubbard B, Doege H, Punreddy S, Wu H, Huang X, Kaushik VK, Mozell RL, Byrnes JJ, Stricker-Krongrad A, Chou CJ, Tartaglia LA, Lodish HF, Stahl A, Gimeno RE. Mice deleted for fatty acid transport protein 5 have defective bile acid conjugation and are protected from obesity. Gastroenterology 2006; 130:1259-69. [PMID: 16618417 DOI: 10.1053/j.gastro.2006.02.012] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Accepted: 01/04/2006] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Fatty Acid Transport Protein 5 (FATP5) is a liver-specific member of the FATP/Slc27 family, which has been shown to exhibit both fatty acid transport and bile acid-CoA ligase activity in vitro. Here, we investigate its role in bile acid metabolism and body weight homeostasis in vivo by using a novel FATP5 knockout mouse model. METHODS Bile acid composition was analyzed by mass spectroscopy. Body weight, food intake, energy expenditure, and fat absorption were determined in animals fed either a low- or a high-fat diet. RESULTS Although total bile acid concentrations were unchanged in bile, liver, urine, and feces of FATP5 knockout mice, the majority of gallbladder bile acids was unconjugated, and only a small percentage was conjugated. Primary, but not secondary, bile acids were detected among the remaining conjugated forms in FATP5 deletion mice, suggesting a specific requirement for FATP5 in reconjugation of bile acids during the enterohepatic recirculation. Fat absorption in FATP5 deletion mice was largely normal, and only a small increase in fecal fat was observed on a high-fat diet. Despite normal fat absorption, FATP5 deletion mice failed to gain weight on a high-fat diet because of both decreased food intake and increased energy expenditure. CONCLUSIONS Our findings reveal an important role for FATP5 in bile acid conjugation in vivo and an unexpected function in body weight homeostasis, which will require further analysis. FATP5 deletion mice provide a new model to study the intersection of bile acid metabolism, lipid metabolism, and body weight regulation.
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Affiliation(s)
- Brian Hubbard
- Millennium Pharmaceuticals, Inc, Cambridge, Massachusetts 02140, USA
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Mita S, Suzuki H, Akita H, Hayashi H, Onuki R, Hofmann AF, Sugiyama Y. Vectorial transport of unconjugated and conjugated bile salts by monolayers of LLC-PK1 cells doubly transfected with human NTCP and BSEP or with rat Ntcp and Bsep. Am J Physiol Gastrointest Liver Physiol 2006; 290:G550-6. [PMID: 16474011 DOI: 10.1152/ajpgi.00364.2005] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Na(+)-taurocholate-cotransporting peptide (NTCP)/SLC10A1 and bile salt export pump (BSEP)/ABCB11 synergistically play an important role in the transport of bile salts by the hepatocyte. In this study, we transfected human NTCP and BSEP or rat Ntcp and Bsep into LLC-PK1 cells, a cell line devoid of bile salts transporters. Transport by these cells was characterized with a focus on substrate specificity between rats and humans. The basal to apical flux of taurocholate across NTCP- and BSEP-expressing LLC-PK1 monolayers was 10 times higher than that in the opposite direction, whereas the flux across the monolayer of control and NTCP or BSEP single-expressing cells did not show any vectorial transport. The basal to apical flux of taurocholate was saturated with a K(m) value of 20 microM. Vectorial transcellular transport was also observed for cholate, chenodeoxycholate, ursodeoxycholate, their taurine and glycine conjugates, and taurodeoxycholate and glycodeoxycholate, whereas no transport of lithocholate was detected. To evaluate the respective functions of NTCP and BSEP and to compare them with those of rat Ntcp and Bsep, we calculated the clearance by each transporter in this system. A good correlation in the clearance of the examined bile salts (cholate, chenodeoxycholate, ursodeoxycholate, and their taurine or glycine conjugates) was observed between transport by human and that of rat transporters in terms of their rank order: for NTCP, taurine conjugates > glycine conjugates > unconjugated bile salts, and for BSEP, unconjugated bile salts and glycine conjugates > taurine conjugates. In conclusion, the substrate specificity of human and rat NTCP and BSEP appear to be very similar at least for monovalent bile salts under physiological conditions.
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Affiliation(s)
- Sachiko Mita
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Shitara Y, Horie T, Sugiyama Y. Transporters as a determinant of drug clearance and tissue distribution. Eur J Pharm Sci 2006; 27:425-46. [PMID: 16488580 DOI: 10.1016/j.ejps.2005.12.003] [Citation(s) in RCA: 311] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 12/01/2005] [Accepted: 12/06/2005] [Indexed: 01/02/2023]
Abstract
Transporters play an important role in the processes of drug absorption, distribution and excretion. In this review, we have focused on the involvement of transporters in drug excretion in the liver and kidney. The rate of transporter-mediated uptake and efflux determines the rate of renal and hepatobiliary elimination. Transporters are thus important as a determinant of the clearance in the body. Even when drugs ultimately undergo metabolism, their elimination rate is sometimes determined by the uptake rate mediated by transporters. Transporters regulate the pharmacological and/or toxicological effect of drugs because they limit their distribution to tissues responsible for their effect and/or toxicity. For example, the liver-specific distribution of some statins via organic anion transporters helps them to produce their high pharmacological effect. On the other hand, as in the case of metformin taken up by organic cation transporter 1, drug distribution to the tissue(s) may enhance its toxicity. As transporter-mediated uptake is a determinant of the drug elimination rate, drug-drug interactions involving the process of transporter-mediated uptake can occur. In this review, we have introduced some examples and described their mechanisms. More recently, some methods to analyze such transporter-mediated transport have been reported. The estimation of the contributions of transporters to the net clearance of a drug makes it possible to predict the net clearance from data involving drug transport in transporter-expressing cells. Double transfected cells, where both uptake and efflux transporters are expressed on the same polarized cells, are also helpful for the analysis of the rate of transporter-mediated transcellular transport.
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Affiliation(s)
- Yoshihisa Shitara
- Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chou-ku, Chiba 260-8675, Japan
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Abstract
Conjugates of endogenous substances and of xenobiotics, formed extrahepatically or inside hepatocytes, undergo vectorial transport into bile. Substances conjugated with glucuronate, sulfate, or glutathione are substrates for organic anion uptake transporters in the basolateral (sinusoidal) membrane as well as substrates for the unidirectional ATP-driven conjugate efflux pump in the apical (canalicular) membrane, termed multidrug resistance protein 2 (MRP2; systematic name ABCC2). Localization of the efflux pumps ABCC3 and ABCC4 to the basolateral membrane of human hepatocytes has provided insight into the molecular mechanisms of conjugate efflux from hepatocytes into blood, as exemplified by the efflux of bilirubin glucuronosides mediated by ABCC3. The cloning and stable expression of the complementary DNAs encoding the organic anion transporters in the basolateral membrane of human hepatocytes and of members of the ABCC subfamily of efflux pumps in the apical as well as in the basolateral membrane have improved our understanding of hepatobiliary elimination and of the substrate specificity with respect to anionic conjugates. The stable expression of human hepatocyte uptake and efflux transporters in polarized cell lines, as described in this chapter, provides valuable tools for the in vitro analysis of human hepatobiliary transport in general and specifically for uptake and efflux of the anionic conjugates formed in various phase 2 reactions.
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Hayashi H, Takada T, Suzuki H, Onuki R, Hofmann AF, Sugiyama Y. Transport by vesicles of glycine- and taurine-conjugated bile salts and taurolithocholate 3-sulfate: a comparison of human BSEP with rat Bsep. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1738:54-62. [PMID: 16332456 DOI: 10.1016/j.bbalip.2005.10.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 10/17/2005] [Accepted: 10/25/2005] [Indexed: 01/11/2023]
Abstract
The bile salt export pump (BSEP) of hepatocyte secretes conjugated bile salts across the canalicular membrane in an ATP-dependent manner. The biliary bile salts of human differ from those of rat in containing a greater proportion of glycine conjugates and taurolithocholate 3-sulfate (TLC-S). In the present study, the transport properties of hBSEP and rBsep were investigated using membrane vesicles from HEK293 cells infected with recombinant adenoviruses containing hBSEP or rBsep cDNA. ATP-dependent uptake of radiolabeled glycine-, taurine-conjugated bile salts, and [(3)H]cholate was observed when hBSEP or rBsep was expressed. Comparison of initial uptake rates indicated that for both transporters, taurine-conjugated bile salts were transported more rapidly than glycine-conjugated bile salts, however, hBSEP transported glycine conjugates to an extent that was approximately 2-fold greater than rBsep. In addition, [(3)H]TLC-S was significantly transported by hBSEP, and hardly transported by rBsep. The mean K(m) value for the uptake of [(3)H]TLC-S by hBSEP was 9.5+/-1.5 microM, a value similar to that for hMRP2 (8.2+/-1.3 microM). In conclusion, both hBSEP and rBsep transport taurine-conjugated bile salts better than glycine-conjugated bile salts, but hBSEP transports glycine conjugates to a greater extent as compared to rBsep. TLC-S, which is present in human bile but not rodent bile, is more avidly transported by hBSEP compared with rBsep.
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Affiliation(s)
- Hisamitsu Hayashi
- Department of Molecular Biopharmaceutics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Sahi J. Use ofin vitrotransporter assays to understand hepatic and renal disposition of new drug candidates. Expert Opin Drug Metab Toxicol 2005; 1:409-27. [PMID: 16863453 DOI: 10.1517/17425255.1.3.409] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Hepatic and renal transporters contribute to the uptake, secretion and reabsorption of endogenous compounds, xenobiotics and their metabolites and have been implicated in drug-drug interactions and toxicities. Characterising the renal and hepatic disposition of drug candidates early in development would lead to more rational drug design, as chemotypes with 'ideal' pharmacokinetic characteristics could be identified and further refined. Because transporters are often organ specific, 'custom' transporter panels need to be identified for each major organ and chemotype to be evaluated, and appropriate studies planned. This review outlines the major renal and hepatic transporters and some of the in vitro transporter reagents, assays and processes that can be used to evaluate the renal and hepatic disposition of new chemical entities during drug discovery and development.
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Affiliation(s)
- Jasminder Sahi
- CELLZDIRECT, 480 Hillsboro Street, Pittsboro, NC 27312, USA.
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Kusuhara H, Sugiyama Y. Active efflux across the blood-brain barrier: role of the solute carrier family. NeuroRx 2005; 2:73-85. [PMID: 15717059 PMCID: PMC539323 DOI: 10.1602/neurorx.2.1.73] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The brain uptake of xenobiotics is restricted by the blood-brain brain barrier formed by brain capillary endothelial cells. Active efflux transport systems in the blood-brain barrier work as a detoxification system in the brain by facilitating removal of xenobiotic compounds from the brain. Drugs, acting in the brain, have to overcome such efflux mechanisms to achieve clinically significant concentration in the brain. Multiple transporters are involved in this efflux transport in the brain capillaries. In the past few years, considerable progress has been made in the cloning of these transporters and their functional characterization after heterologous expression. Members of the solute carrier family (SLC) play an important role in the efflux transport, especially for organic anions, which include organic anion transporting polypeptides (OATP/SLCO) and organic anion transporters (OAT/SLC22A). It is believed that coordination of the members of SLC family, and ABC transporters, such as P-glycoprotein, multidrug resistance protein, and breast cancer-resistant protein (BCRP/ABCG2), allows an efficient vectorial transport across the endothelial cells to remove xenobiotics from the brain. In this review, we shall summarize our current knowledge about their localization, molecular and functional characteristics, and substrate and inhibitor specificity.
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Affiliation(s)
- Hiroyuki Kusuhara
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan.
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Watanabe T, Onuki R, Yamashita S, Taira K, Sugiyama Y. Construction of a Functional Transporter Analysis System Using MDR1 Knockdown Caco-2 Cells. Pharm Res 2005; 22:1287-93. [PMID: 16078138 DOI: 10.1007/s11095-005-5270-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Accepted: 03/11/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE The efflux transporter, P-glycoprotein (P-gp), located in the brush-border membrane of intestinal absorptive cells, reduces the bioavailability of a wide range of orally administered drugs. Using P-gp inhibitors in transport experiments in Caco-2 cell monolayers is widely accepted as an efficient way to estimate the contribution of P-gp to the intestinal absorption of drugs. However, there still remain some arguments that the inhibitors might affect the function of other proteins. Multidrug resistance 1 gene (MDR1) specifically inhibited Caco-2 cells were constructed, therefore, as a better in vitro evaluation system of intestinal drug absorption. METHODS The effective sites of RNAi were selected using siRNA libraries and single siRNAs and MDR1 stable knockdown Caco-2 cells were constructed using a tRNA(val)-shRNA expression vector. RESULTS In siRNA stably expressed Caco-2 cells, the expression level of MDR1 was reduced at mRNA and protein levels. Transcellular transport studies using digoxin revealed that the P-gp function was suppressed completely, similar to that in verapamil-treated cells. CONCLUSIONS MDR1 stable knockdown Caco-2 cells were successfully constructed by RNAi technology. This will consequently allow the development of a selection system for candidate drugs with improved absorption properties.
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MESH Headings
- Biological Transport, Active
- Blotting, Western
- Caco-2 Cells
- Calcium Channel Blockers/pharmacology
- Gene Library
- Genes, MDR/genetics
- Genetic Vectors
- Humans
- Intestinal Absorption
- Membrane Transport Proteins/metabolism
- Models, Biological
- Organisms, Genetically Modified
- RNA Interference/physiology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Small Interfering/chemical synthesis
- RNA, Small Interfering/genetics
- RNA, Transfer, Val/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Transfection
- Verapamil/pharmacology
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Affiliation(s)
- Tomoko Watanabe
- Department of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
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Yang SS, Yamauchi K, Rai T, Hiyama A, Sohara E, Suzuki T, Itoh T, Suda S, Sasaki S, Uchida S. Regulation of apical localization of the thiazide-sensitive NaCl cotransporter by WNK4 in polarized epithelial cells. Biochem Biophys Res Commun 2005; 330:410-4. [PMID: 15796898 DOI: 10.1016/j.bbrc.2005.02.172] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Indexed: 11/18/2022]
Abstract
Missense mutations in the WNK4 gene have been postulated to cause pseudohypoaldosteronism type II (PHAII), an autosomal-dominant disorder characterized by hyperkalemia and hypertension. Previous reports using Xenopus oocytes showed that wild-type WNK4 expression inhibited surface expression of the thiazide-sensitive NaCl cotransporter (NCC), while a disease-causing mutant lost the inhibitory effect on NCC surface expression. To determine if these changes observed in oocytes really occur in polarized epithelial cells, we generated stable MDCK II cell lines expressing NCC alone or NCC plus wild-type WNK4 or a disease-causing (D564A) WNK4. In contrast to the apical localization of NCC without co-expression of WNK4, immunofluorescence microscopy and biotin surface labeling revealed that this apical localization was equally decreased by both the wild-type and the mutant WNK4 expression. Apical localizations of two PHAII-unrelated apical transporters, sodium-independent amino acid transporter, BAT1 and bile salt export pump, Bsep, were also found to be decreased by both wild-type and mutant WNK4 expression. These results indicate that the regulation of NCC was not related to the disease-causing mutation and not restricted to the PHAII-related specific transporters. The regulation of intracellular localization of NCC by WNK4 might not be involved in the pathogenesis of PHAII.
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Affiliation(s)
- Sung-Sen Yang
- Department of Nephrology, Graduate School of Medicine, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo, Tokyo 113-8519, Japan
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