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Metry M, Dirda ND, Raufman JP, Polli JE, Kao JPY. Novel nitroxide-bile acid conjugates inform substrate requirements for human bile acid transporters. Eur J Pharm Sci 2023; 180:106335. [PMID: 36402308 PMCID: PMC9908032 DOI: 10.1016/j.ejps.2022.106335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 11/10/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022]
Abstract
Transport of bile acids within the enterohepatic circulation from the liver to the intestines via the gallbladder and back to the liver via the portal vein plays a critical role in bile acid regulation and homeostasis. Deficiency of fibroblast growth factor 19 (FGF19), a hormone whose role is to suppress de novo hepatic bile acid synthesis to maintain homeostatic levels, results in bile acid diarrhea (BAD). FGF19 also modulates gallbladder motility so that bile acids are concentrated in the gallbladder until postprandial contraction. To assess bile acid transport and diagnose ailments like BAD that are associated with altered bile acid synthesis and transport, we created bile acid conjugates with nitroxide radicals. Because nitroxides are paramagnetic and can promote proton relaxation, we reasoned that these paramagnetic conjugates should act as contrast agents in in vivo magnetic resonance imaging (MRI). We tested substrate capability by assessing the inhibitory potential of these novel agents against taurocholate uptake by the apical sodium dependent bile acid transporter (ASBT) and the Na+/taurocholate cotransporting polypeptide (NTCP). Surprisingly, neither the paramagnetic compounds CA-Px-1 and CA-Px-2, nor their reduced forms, CA-Px-1H and CA-Px-2H, inhibited hASBT- or hNTCP-mediated taurocholate uptake. Therefore, the new conjugates cannot serve as contrast agents for MRI in vivo. However, our findings identify important structural constraints of transportable bile acid conjugates and suggest potential modifications to overcome these limitations.
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Affiliation(s)
- Melissa Metry
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, N623, Baltimore, MD 21201, United States
| | - Nathaniel D.A. Dirda
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Jean-Pierre Raufman
- VA Maryland Healthcare System, Department of Medicine, Division of Gastroenterology & Hepatology, Department of Biochemistry and Molecular Biology, and the Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - James E. Polli
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, N623, Baltimore, MD 21201, United States,Corresponding author: (J.E. Polli)
| | - Joseph P. Y. Kao
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
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Leuenberger M, Häusler S, Höhn V, Euler A, Stieger B, Lochner M. Characterization of Novel Fluorescent Bile Salt Derivatives for Studying Human Bile Salt and Organic Anion Transporters. J Pharmacol Exp Ther 2021; 377:346-357. [PMID: 33782042 DOI: 10.1124/jpet.120.000449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/23/2021] [Indexed: 11/22/2022] Open
Abstract
Bile salts, such as cholate, glycocholate, taurocholate, and glycochenodeoxycholate, are taken up from the portal blood into hepatocytes via transporters, such as the Na+-taurocholate-cotransporting polypeptide (NTCP) and organic anion-transporting polypeptides (OATPs). These bile salts are later secreted into bile across the canalicular membrane, which is facilitated by the bile salt export pump (BSEP). Apart from bile salt transport, some of these proteins (e.g., OATPs) are also key transporters for drug uptake into hepatocytes. In vivo studies of transporter function in patients by using tracer compounds have emerged as an important diagnostic tool to complement classic liver parameter measurements by determining dynamic liver function both for diagnosis and monitoring progression or improvement of liver diseases. Such approaches include use of radioactively labeled bile salts (e.g., for positron emission tomography) and fluorescent bile salt derivatives or dyes (e.g., indocyanine green). To expand the list of liver function markers, we synthesized fluorescent derivatives of cholic and chenodeoxycholic acid by conjugating small organic dyes to the bile acid side chain. These novel fluorescent probes were able to block substrate transport in a concentration-dependent manner of NTCP, OATP1B1, OATP1B3, OATP2B1, BSEP, and intestinal apical sodium-dependent bile salt transporter (ASBT). Whereas the fluorescent bile acid derivatives themselves were transported across the membrane by OATP1B1, OATP1B3, and OATP2B1, they were not transport substrates for NTCP, ASBT, BSEP, and multidrug resistance-related protein 2. Accordingly, these novel fluorescent bile acid probes can potentially be used as imaging agents to monitor the function of OATPs. SIGNIFICANCE STATEMENT: Synthetic modification of common bile acids by attachment of small organic fluorescent dyes to the bile acid side chain resulted in bright, fluorescent probes that interact with hepatic and intestinal organic anion [organic anion-transporting polypeptide (OATP) 1B1, OATP1B3, OATP2B1], bile salt uptake (Na+-taurocholate-cotransporting polypeptide, apical sodium-dependent bile salt transporter), and bile salt efflux (bile salt export pump, multidrug resistance-related protein 2) transporters. Although the fluorescent bile salt derivatives are taken up into cells via the OATPs, the efflux transporters do not transport any of them but one.
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Affiliation(s)
- Michele Leuenberger
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland (M.Le., M.Lo.); Department of Clinical Pharmacology and Toxicology, University Hospital Zürich, Zürich, Switzerland (S.H., V.H., A.E., B.S.); and Swiss National Center of Competence in Research, NCCR TransCure, Bern, Switzerland (M.Le., S.H., A.E., B.S., M.Lo.)
| | - Stephanie Häusler
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland (M.Le., M.Lo.); Department of Clinical Pharmacology and Toxicology, University Hospital Zürich, Zürich, Switzerland (S.H., V.H., A.E., B.S.); and Swiss National Center of Competence in Research, NCCR TransCure, Bern, Switzerland (M.Le., S.H., A.E., B.S., M.Lo.)
| | - Vera Höhn
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland (M.Le., M.Lo.); Department of Clinical Pharmacology and Toxicology, University Hospital Zürich, Zürich, Switzerland (S.H., V.H., A.E., B.S.); and Swiss National Center of Competence in Research, NCCR TransCure, Bern, Switzerland (M.Le., S.H., A.E., B.S., M.Lo.)
| | - Adriana Euler
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland (M.Le., M.Lo.); Department of Clinical Pharmacology and Toxicology, University Hospital Zürich, Zürich, Switzerland (S.H., V.H., A.E., B.S.); and Swiss National Center of Competence in Research, NCCR TransCure, Bern, Switzerland (M.Le., S.H., A.E., B.S., M.Lo.)
| | - Bruno Stieger
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland (M.Le., M.Lo.); Department of Clinical Pharmacology and Toxicology, University Hospital Zürich, Zürich, Switzerland (S.H., V.H., A.E., B.S.); and Swiss National Center of Competence in Research, NCCR TransCure, Bern, Switzerland (M.Le., S.H., A.E., B.S., M.Lo.)
| | - Martin Lochner
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland (M.Le., M.Lo.); Department of Clinical Pharmacology and Toxicology, University Hospital Zürich, Zürich, Switzerland (S.H., V.H., A.E., B.S.); and Swiss National Center of Competence in Research, NCCR TransCure, Bern, Switzerland (M.Le., S.H., A.E., B.S., M.Lo.)
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Chen T, Reich NW, Bell N, Finn PD, Rodriguez D, Kohler J, Kozuka K, He L, Spencer AG, Charmot D, Navre M, Carreras CW, Koo-McCoy S, Tabora J, Caldwell JS, Jacobs JW, Lewis JG. Design of Gut-Restricted Thiazolidine Agonists of G Protein-Coupled Bile Acid Receptor 1 (GPBAR1, TGR5). J Med Chem 2018; 61:7589-7613. [DOI: 10.1021/acs.jmedchem.8b00308] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Tao Chen
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | | | - Noah Bell
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Patricia D. Finn
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - David Rodriguez
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Jill Kohler
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Kenji Kozuka
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Limin He
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Andrew G. Spencer
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Dominique Charmot
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Marc Navre
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | | | - Samantha Koo-McCoy
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Jocelyn Tabora
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Jeremy S. Caldwell
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Jeffrey W. Jacobs
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
| | - Jason Gustaf Lewis
- Ardelyx, Inc., 34175 Ardenwood Blvd, Fremont, California 94555, United States
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4
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Fang Y, Liang F, Liu K, Qaiser S, Pan S, Xu X. Structure characteristics for intestinal uptake of flavonoids in Caco-2 cells. Food Res Int 2018; 105:353-360. [DOI: 10.1016/j.foodres.2017.11.045] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/17/2017] [Accepted: 11/19/2017] [Indexed: 12/20/2022]
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Zhang D, Li D, Shang L, He Z, Sun J. Transporter-targeted cholic acid-cytarabine conjugates for improved oral absorption. Int J Pharm 2016; 511:161-169. [PMID: 27377011 DOI: 10.1016/j.ijpharm.2016.06.139] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/17/2016] [Accepted: 06/30/2016] [Indexed: 10/21/2022]
Abstract
Cytarabine has a poor oral absorption due to its rapid deamination and poor membrane permeability. Bile acid transporters are highly expressed both in enterocytes and hepatocytes and to increase the oral bioavailability and investigate the potential application of cytarabine for liver cancers, a transporter- recognizing prodrug strategy was applied to design and synthesize four conjugates of cytarabine with cholic acid (CA), chenodeoxycholic acid (CDCA), hyodeoxycholic acid (HDCA) and ursodeoxycholic acid (UDCA). The anticancer activities against HepG2 cells were evaluated by MTT assay and the role of bile acid transporters during cellular transport was investigated in a competitive inhibition experiment. The in vitro and in vivo metabolic stabilities of these conjugates were studied in rat plasma and liver homogenates. Finally, an oral bioavailability study was conducted in rats. All the cholic acid-cytarabine conjugates (40μM) showed potent antiproliferative activities (up to 70%) against HepG2 cells after incubation for 48h. The addition of bile acids could markedly reduce the antitumor activities of these conjugates. The N(4)-ursodeoxycholic acid conjugate of cytarabine (compound 5) exhibited optimal stability (t1/2=90min) in vitro and a 3.9-fold prolonged half-life of cytarabine in vivo. More importantly, compound 5 increased the oral bioavailability 2-fold compared with cytarabine. The results of the present study suggest that the prodrug strategy based on the bile acid transporters is suitable for improving the oral absorption and the clinical application of cytarabine.
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Affiliation(s)
- Dong Zhang
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang, 110016, China
| | - Dongpo Li
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang, 110016, China; State Key Lab of New-tech for Chinese Medicine Pharmaceutical Processes, Lianyungang, 222001, China
| | - Lei Shang
- School of Pharmacy, China Medical University, Shenyang 110122, China.
| | - Zhonggui He
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang, 110016, China
| | - Jin Sun
- Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang, 110016, China.
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6
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Faustino C, Serafim C, Rijo P, Reis CP. Bile acids and bile acid derivatives: use in drug delivery systems and as therapeutic agents. Expert Opin Drug Deliv 2016; 13:1133-48. [DOI: 10.1080/17425247.2016.1178233] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Célia Faustino
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Cláudia Serafim
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Patrícia Rijo
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
- Universidade Lusófona de Humanidades e Tecnologias, Escola de Ciências e Tecnologias da Saúde, Research Center for Biosciences and Healht Technologies (CBIOS), Lisbon, Portugal
| | - Catarina Pinto Reis
- Universidade Lusófona de Humanidades e Tecnologias, Escola de Ciências e Tecnologias da Saúde, Research Center for Biosciences and Healht Technologies (CBIOS), Lisbon, Portugal
- Biophysics and Biomedical Engineering Institute (IBEB), Faculty of Sciences, Universidade de Lisboa, Lisbon, Portugal
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7
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Dong Z, Li Q, Guo D, Shu Y, Polli JE. Synthesis and Evaluation of Bile Acid-Ribavirin Conjugates as Prodrugs to Target the Liver. J Pharm Sci 2015; 104:2864-76. [PMID: 25645375 DOI: 10.1002/jps.24375] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 12/07/2014] [Accepted: 01/08/2015] [Indexed: 11/08/2022]
Abstract
Ribavirin is used to treat hepatitis C but causes serious hemolytic anemia. The objective of the study was to develop a ribavirin prodrug to achieve liver-specific drug delivery and to reduce its off-target effect in red blood cells (RBCs). The approach aimed to target the human sodium taurocholate cotransporting polypeptide (NTCP), which is a bile acid transporter predominately expressed in the liver. Six prodrugs with ribavirin conjugation at C-3 or C-24 of the bile acids were synthesized. In vitro uptake studies indicated that all six prodrugs were NTCP substrates. Metabolic studies in vitro indicated that ribavirin-l-Val-glycochenodeoxycholic acid (GCDCA) was able to release ribavirin in the mouse liver S9 fraction. Additionally, in vitro studies showed that ribavirin in RBC was reduced by 16.7-fold from prodrug compared with parent drug incubation. Moreover, almost no prodrug was present in RBC. In vivo study in mice also showed that ribavirin-l-Val-GCDCA could provide almost the same ribavirin exposure in the liver as ribavirin administration, but with about 1.8-fold less exposure of ribavirin in RBC, plasma, and kidney. Overall, the study suggested that ribavirin-l-Val-GCDCA has the potential to achieve ribavirin-specific liver delivery.
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Affiliation(s)
- Zhongqi Dong
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, 21201
| | - Qing Li
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, 21201
| | - Dong Guo
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, 21201
| | - Yan Shu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, 21201
| | - James E Polli
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland, 21201
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8
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Fang ZZ, Krausz KW, Nagaoka K, Tanaka N, Gowda K, Amin SG, Perdew GH, Gonzalez FJ. In vivo effects of the pure aryl hydrocarbon receptor antagonist GNF-351 after oral administration are limited to the gastrointestinal tract. Br J Pharmacol 2014; 171:1735-46. [PMID: 24417285 PMCID: PMC3966752 DOI: 10.1111/bph.12576] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/23/2013] [Accepted: 12/20/2013] [Indexed: 02/02/2023] Open
Abstract
Background and Purpose GNF-351 is a potent aryl hydrocarbon receptor (AHR) antagonist that inhibits dioxin response element-dependent and independent activities. Here, the absorption, metabolism and in vivo AHR antagonist activity of GNF-351 were investigated. Experimental Approach LC-MS metabolomics was used to analyse GNF-351 metabolism in vitro and in vivo. Recombinant drug-metabolizing enzymes were employed to determine the enzymes involved in GNF-351 metabolism. Analysis of target AHR genes was performed to investigate the inhibitory effects of GNF-351 towards AHR activation. Key Results Several phase I metabolites were generated after GNF-351 was incubated with microsomes from human or mouse liver and intestine, including two oxidized GNF-351 and one tri-demethylated GNF-351. Poor absorption from the intestine resulted in no detectable levels of GNF-351 in mouse serum (0–6 h) and urine (24 h) and almost all GNF-351 was found in the faeces after 24 h. Analysis of faeces further revealed all the in vitro phase I metabolites. Novel metabolites were detected, including one di-oxidized GNF-351, two oxidized and tri-demethylated GNF-351, one dehydrogenated product of oxidized GNF-351, and one sulfation product of di-oxidized GNF-351. Cytochromes P450 were demonstrated to be the major enzymes involved in metabolism of GNF-351. After oral administration to mice, GNF-351 readily inhibited β-naphthoflavone-induced AHR activation in ileum and colon, but not that in the liver. Conclusion and Implications While poor absorption and extensive metabolism after oral administration limited the in vivo effects of the pure AHR antagonist GNF-351 in liver, it could be used to inhibit AHR activation in intestine and colon.
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Affiliation(s)
- Zhong-Ze Fang
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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9
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Vivian D, Polli JE. Mechanistic interpretation of conventional Michaelis-Menten parameters in a transporter system. Eur J Pharm Sci 2014; 64:44-52. [PMID: 25169756 DOI: 10.1016/j.ejps.2014.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 07/22/2014] [Accepted: 08/17/2014] [Indexed: 11/24/2022]
Abstract
The aim was to elucidate how steps in drug translocation by a solute carrier transporter impact Michaelis-Menten parameters Km, Ki, and Vmax. The first objective was to derive a model for carrier-mediated substrate translocation and perform sensitivity analysis with regard to the impact of individual microrate constants on Km, Ki, and Vmax. The second objective was to compare underpinning microrate constants between compounds translocated by the same transporter. Equations for Km, Ki, and Vmax were derived from a six-state model involving unidirectional transporter flipping and reconfiguration. This unidirectional model is applicable to co-transporter type solute carriers, like the apical sodium-dependent bile acid transporter (ASBT) and the proton-coupled peptide cotransporter (PEPT1). Sensitivity analysis identified the microrate constants that impacted Km, Ki, and Vmax. Compound comparison using the six-state model employed regression to identify microrate constant values that can explain observed Km and Vmax values. Results yielded some expected findings, as well as some unanticipated effects of microrate constants on Km, Ki, and Vmax. Km and Ki were found to be equal for inhibitors that are also substrates. Additionally, microrate constant values for certain steps in transporter functioning influenced Km and Vmax to be low or high.
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Affiliation(s)
- Diana Vivian
- University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - James E Polli
- University of Maryland School of Pharmacy, Baltimore, MD 21201, USA.
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YANG KYUNGHEE, KÖCK KATHLEEN, SEDYKH ALEXANDER, TROPSHA ALEXANDER, BROUWER KIML. An updated review on drug-induced cholestasis: mechanisms and investigation of physicochemical properties and pharmacokinetic parameters. J Pharm Sci 2013; 102:3037-57. [PMID: 23653385 PMCID: PMC4369767 DOI: 10.1002/jps.23584] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/13/2013] [Accepted: 04/16/2013] [Indexed: 12/15/2022]
Abstract
Drug-induced cholestasis is an important form of acquired liver disease and is associated with significant morbidity and mortality. Bile acids are key signaling molecules, but they can exert toxic responses when they accumulate in hepatocytes. This review focuses on the physiological mechanisms of drug-induced cholestasis associated with altered bile acid homeostasis due to direct (e.g., bile acid transporter inhibition) or indirect (e.g., activation of nuclear receptors, altered function/expression of bile acid transporters) processes. Mechanistic information about the effects of a drug on bile acid homeostasis is important when evaluating the cholestatic potential of a compound, but experimental data often are not available. The relationship between physicochemical properties, pharmacokinetic parameters, and inhibition of the bile salt export pump among 77 cholestatic drugs with different pathophysiological mechanisms of cholestasis (i.e., impaired formation of bile vs. physical obstruction of bile flow) was investigated. The utility of in silico models to obtain mechanistic information about the impact of compounds on bile acid homeostasis to aid in predicting the cholestatic potential of drugs is highlighted.
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Affiliation(s)
- KYUNGHEE YANG
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - KATHLEEN KÖCK
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - ALEXANDER SEDYKH
- Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - ALEXANDER TROPSHA
- Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - KIM L.R. BROUWER
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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11
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Zhang Z, Gao F, Jiang S, Chen L, Liu Z, Yu H, Li Y. Bile salts enhance the intestinal absorption of lipophilic drug loaded lipid nanocarriers: Mechanism and effect in rats. Int J Pharm 2013; 452:374-81. [DOI: 10.1016/j.ijpharm.2013.05.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 03/08/2013] [Accepted: 05/03/2013] [Indexed: 10/26/2022]
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12
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Döring B, Lütteke T, Geyer J, Petzinger E. The SLC10 carrier family: transport functions and molecular structure. CURRENT TOPICS IN MEMBRANES 2013. [PMID: 23177985 DOI: 10.1016/b978-0-12-394316-3.00004-1] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The SLC10 family represents seven genes containing 1-12 exons that encode proteins in humans with sequence lengths of 348-477 amino acids. Although termed solute carriers (SLCs), only three out of seven (i.e. SLC10A1, SLC10A2, and SLC10A6) show sodium-dependent uptake of organic substrates across the cell membrane. These include the uptake of bile salts, sulfated steroids, sulfated thyroidal hormones, and certain statin drugs by SLC10A1 (Na(+)-taurocholate cotransporting polypeptide (NTCP)), the uptake of bile salts by SLC10A2 (apical sodium-dependent bile acid transporter (ASBT)), and uptake of sulfated steroids and sulfated taurolithocholate by SLC10A6 (sodium-dependent organic anion transporter (SOAT)). The other members of the family are orphan carriers not all localized in the cell membrane. The name "bile acid transporter family" arose because the first two SLC10 members (NTCP and ASBT) are carriers for bile salts that establish their enterohepatic circulation. In recent years, information has been obtained on their 2D and 3D membrane topology, structure-transport relationships, and on the ligand and sodium-binding sites. For SLC10A2, the putative 3D morphology was deduced from the crystal structure of a bacterial SLC10A2 analog, ASBT(NM). This information was used in this chapter to calculate the putative 3D structure of NTCP. This review provides first an introduction to recent knowledge about bile acid synthesis and newly found bile acid hormonal functions, and then describes step-by-step each individual member of the family in terms of expression, localization, substrate pattern, as well as protein topology with emphasis on the three functional SLC10 carrier members.
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Affiliation(s)
- Barbara Döring
- SLC10 family research group, Institute of Pharmacology and Toxicology, Justus Liebig University Giessen, Biomedical Research Center (BFS), Giessen, Germany
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13
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Vivian D, Cheng K, Khurana S, Xu S, Whiterock V, Witter D, Lentz KA, Santone KS, Raufman JP, Polli JE. Design and characterization of a novel fluorinated magnetic resonance imaging agent for functional analysis of bile Acid transporter activity. Pharm Res 2013; 30:1240-51. [PMID: 23319170 DOI: 10.1007/s11095-012-0963-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/11/2012] [Indexed: 01/09/2023]
Abstract
PURPOSE To synthesize a trifluorinated bile acid that can be used for (19)F magnetic resonance imaging (MRI) of bile acid enterohepatic circulation, characterize its in vitro transporter affinity, stability, and (19)F-MRI signal, and assess its ability to concentrate in the gallbladder of C57BL/6 mice. METHODS Target compound CA-lys-TFA was synthesized and tested for affinity toward the apical sodium dependent bile acid transporter (hASBT) and the Na+/taurocholate cotransporting polypeptide (hNTCP). In a pilot study, fasted mice were gavaged with vehicle control, 150 mg/kg or 300 mg/kg CA-lys-TFA. CA-lys-TFA in gallbladder, liver and plasma at t = 5 h was quantified. Additionally, a 24-h time course (24 mice across eight time points) was studied using 50 mg/kg CA-lys-TFA. RESULTS CA-lys-TFA was a potent substrate of hASBT (Kt = 39.4 μM, normalized Vmax = 0.853) and hNTCP (Kt = 8.99 μM, normalized Vmax = 0.281). (19)F MRI phantom imaging showed linear signal-concentration dependence. In vivo studies showed that rapid accumulation of CA-lys-TFA in the gallbladder was maximal within 4-7 h. CONCLUSIONS These findings suggest that CA-lys-TFA, a fluorinated non-radioactive bile acid analogue, has potential for use in MRI to measure in vivo bile acid transport and diagnose bile acid malabsorption and other conditions associated with impaired bile acid transport.
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Affiliation(s)
- Diana Vivian
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, USA
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Vanommeslaeghe K, MacKerell AD. Automation of the CHARMM General Force Field (CGenFF) I: bond perception and atom typing. J Chem Inf Model 2012; 52:3144-54. [PMID: 23146088 DOI: 10.1021/ci300363c] [Citation(s) in RCA: 1212] [Impact Index Per Article: 101.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Molecular mechanics force fields are widely used in computer-aided drug design for the study of drug-like molecules alone or interacting with biological systems. In simulations involving biological macromolecules, the biological part is typically represented by a specialized biomolecular force field, while the drug is represented by a matching general (organic) force field. In order to apply these general force fields to an arbitrary drug-like molecule, functionality for assignment of atom types, parameters, and charges is required. In the present article, which is part I of a series of two, we present the algorithms for bond perception and atom typing for the CHARMM General Force Field (CGenFF). The CGenFF atom typer first associates attributes to the atoms and bonds in a molecule, such as valence, bond order, and ring membership among others. Of note are a number of features that are specifically required for CGenFF. This information is then used by the atom typing routine to assign CGenFF atom types based on a programmable decision tree. This allows for straightforward implementation of CGenFF's complicated atom typing rules and for equally straightforward updating of the atom typing scheme as the force field grows. The presented atom typer was validated by assigning correct atom types on 477 model compounds including in the training set as well as 126 test-set molecules that were constructed to specifically verify its different components. The program may be utilized via an online implementation at https://www.paramchem.org/ .
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Affiliation(s)
- K Vanommeslaeghe
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201, USA
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15
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Ekins S, Polli JE, Swaan PW, Wright SH. Computational modeling to accelerate the identification of substrates and inhibitors for transporters that affect drug disposition. Clin Pharmacol Ther 2012; 92:661-5. [PMID: 23010651 DOI: 10.1038/clpt.2012.164] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- S Ekins
- Collaborations in Chemistry, Fuquay Varina, North Carolina, USA.
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Zhu X, Lopes PEM, Shim J, MacKerell AD. Intrinsic energy landscapes of amino acid side-chains. J Chem Inf Model 2012; 52:1559-72. [PMID: 22582825 PMCID: PMC3398815 DOI: 10.1021/ci300079j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Amino acid side-chain conformational properties influence the overall structural and dynamic properties of proteins and, therefore, their biological functions. In this study, quantum mechanical (QM) potential energy surfaces for the rotation of side-chain χ(1) and χ(2) torsions in dipeptides in the alphaR, beta, and alphaL backbone conformations were calculated. The QM energy surfaces provide a broad view of the intrinsic conformational properties of each amino acid side-chain. The extent to which intrinsic energetics dictates side-chain orientation was studied through comparisons of the QM energy surfaces with χ(1) and χ(2) free energy surfaces from probability distributions obtained from a survey of high resolution crystal structures. In general, the survey probability maxima are centered in minima of the QM surfaces as expected for sp(3) (or sp(2) for χ(2) of Asn, Phe, Trp, and Tyr) atom centers with strong variations between amino acids occurring in the energies of the minima indicating intrinsic differences in rotamer preferences. High correlations between the QM and survey data were found for hydrophobic side-chains except Met, suggesting minimal influence of the protein and solution environments on their conformational distributions. Conversely, low correlations for polar or charged side-chains indicate a dominant role of the environment in stabilizing conformations that are not intrinsically favored. Data also link the presence of off-rotamers in His and Trp to favorable interactions with the backbone. Results also suggest that the intrinsic energetics of the side-chains of Phe and Tyr may play important roles in protein folding and stability. Analyses on whether intrinsic side-chain energetics can influence backbone preference identified a strong correlation for residues in the alphaL backbone conformation. It is suggested that this correlation reflects the intrinsic instability of the alphaL backbone such that assumption of this backbone conformation is facilitated by intrinsically favorable side-chain conformations. Together our results offer a broad overview of the conformational properties of amino acid side-chains and the QM data may be used as target data for force field optimization.
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Affiliation(s)
- Xiao Zhu
- Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, 20 Penn Street HSFII, Baltimore, Maryland 21201, USA
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17
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Deconstructing 14-phenylpropyloxymetopon: minimal requirements for binding to mu opioid receptors. Bioorg Med Chem 2012; 20:4556-63. [PMID: 22677527 DOI: 10.1016/j.bmc.2012.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 04/27/2012] [Accepted: 05/04/2012] [Indexed: 01/27/2023]
Abstract
A series of phenylpropyloxyethylamines and cinnamyloxyethylamines were synthesized as deconstructed analogs of 14-phenylpropyloxymetopon and analyzed for opioid receptor binding affinity. Using the Conformationally Sampled Pharmacophore modeling approach, we discovered a series of compounds lacking a tyrosine mimetic, historically considered essential for μ opioid binding. Based on the binding studies, we have identified the optimal analogs to be N-methyl-N-phenylpropyl-2-(3-phenylpropoxy)ethanamine, with 1520 nM, and 2-(cinnamyloxy)-N-methyl-N-phenethylethanamine with 1680 nM affinity for the μ opioid receptor. These partial opioid structure analogs will serve as the novel lead compounds for future optimization studies.
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18
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Kolhatkar V, Polli JE. Structural requirements of bile acid transporters: C-3 and C-7 modifications of steroidal hydroxyl groups. Eur J Pharm Sci 2012; 46:86-99. [PMID: 22387310 DOI: 10.1016/j.ejps.2012.02.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 01/27/2012] [Accepted: 02/20/2012] [Indexed: 10/28/2022]
Abstract
The apical sodium dependent bile acid transporter (ASBT) and sodium-taurocholate cotransporting polypeptide (NTCP) are potential prodrug targets, but the structural requirements for these transporters are incompletely defined. The objective of this study was to evaluate the effect of C-3 and C-7 substitution on bile acid interaction with these bile acid transporters. Nineteen bile acid analogs were tested against ASBT and NTCP for binding, as well as translocation. Results indicated that ASBT and NTCP accommodated a wide range of substituents for binding, but all major C-7 modifications resulted in analogs that did not demonstrate active uptake by either ASBT or NTCP. A C-3 modification that was not tolerated at C-7 still afforded translocation via ASBT and NTCP, confirming the relative unacceptability of C-7 modification. Both ASBT and NTCP demonstrated a generally similar binding potency. Results suggest that drug conjugation to the C-3 hydroxyl group, rather than C-7, has potential to lead to a successful prodrug targeting ASBT and NTCP.
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Affiliation(s)
- Vidula Kolhatkar
- Univerisity of Maryland, School of Pharmacy, Baltimore, MD 21201, USA
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Kolhatkar V, Diao L, Acharya C, Mackerell AD, Polli JE. Identification of novel nonsteroidal compounds as substrates or inhibitors of hASBT. J Pharm Sci 2011; 101:116-26. [PMID: 22109685 DOI: 10.1002/jps.22728] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 07/08/2011] [Accepted: 07/19/2011] [Indexed: 11/11/2022]
Abstract
A prodrug approach that employs the human apical sodium dependent bile acid transporter (hASBT) for absorption requires a recognition moiety for hASBT. Bile acids are natural ligands for hASBT, but are hormones with high molecular weight, such that a recognition moiety that is not a bile acid may be advantageous. The objective was to identify nonsteroidal small molecules that could potentially serve as promoieties in the design of prodrugs that target hASBT. Three searches for bile acid analogues were conducted and it involved molecular fingerprints as the computational tools for similarity searching, as well as traditional medicinal chemistry pattern recognition. Sixty-three compounds were tested using a hASBT-Madin-Darby canine kidney cell monolayer model. Twenty-three of these compounds were found to be hASBT inhibitors and represent novel hASBT inhibitors. Three were selected for hASBT uptake studies. Two were substrates, which represent the first reported nonsteroidal substrates of hASBT. Interestingly, each compound lacked a negative charge. These compounds promise to serve as leads to identify hASBT recognition moieties in a prodrug approach to target hASBT to increase drug absorption.
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Affiliation(s)
- Vidula Kolhatkar
- University of Maryland School of Pharmacy, Baltimore, Maryland 21201, USA
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Shim J, MacKerell AD. Computational ligand-based rational design: Role of conformational sampling and force fields in model development. MEDCHEMCOMM 2011; 2:356-370. [PMID: 21716805 PMCID: PMC3123535 DOI: 10.1039/c1md00044f] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A significant number of drug discovery efforts are based on natural products or high throughput screens from which compounds showing potential therapeutic effects are identified without knowledge of the target molecule or its 3D structure. In such cases computational ligand-based drug design (LBDD) can accelerate the drug discovery processes. LBDD is a general approach to elucidate the relationship of a compound's structure and physicochemical attributes to its biological activity. The resulting structure-activity relationship (SAR) may then act as the basis for the prediction of compounds with improved biological attributes. LBDD methods range from pharmacophore models identifying essential features of ligands responsible for their activity, quantitative structure-activity relationships (QSAR) yielding quantitative estimates of activities based on physiochemical properties, and to similarity searching, which explores compounds with similar properties as well as various combinations of the above. A number of recent LBDD approaches involve the use of multiple conformations of the ligands being studied. One of the basic components to generate multiple conformations in LBDD is molecular mechanics (MM), which apply an empirical energy function to relate conformation to energies and forces. The collection of conformations for ligands is then combined with functional data using methods ranging from regression analysis to neural networks, from which the SAR is determined. Accordingly, for effective application of LBDD for SAR determinations it is important that the compounds be accurately modelled such that the appropriate range of conformations accessible to the ligands is identified. Such accurate modelling is largely based on use of the appropriate empirical force field for the molecules being investigated and the approaches used to generate the conformations. The present chapter includes a brief overview of currently used SAR methods in LBDD followed by a more detailed presentation of issues and limitations associated with empirical energy functions and conformational sampling methods.
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