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Zhu L, Su W, Xu X, Shao S, Qin C, Gao R, Wang X, Ma M, Gao J, Zhang Z. Sphincter of Oddi Dysfunction Induces Gallstone by Inhibiting the Expression of ABCB11 via PKC-α. Appl Biochem Biotechnol 2024; 196:5373-5390. [PMID: 38158489 DOI: 10.1007/s12010-023-04818-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
The abnormal increase of Oddi sphincter pressure and total bile duct pressure may play an important role in the formation of cholesterol stones, but the specific molecular mechanism is still unclear. This study aims to investigate it through in vitro and in vivo experiments. A mouse model of Oddi sphincter dysfunction was constructed by stone-inducing diet. We compared the two groups with PKC-α inhibitor GÖ6976 and PKC-α agonist thymeleatoxin. Oddi sphincter pressure and total bile duct pressure were measured. Biochemical analysis of total cholesterol, bile acid and bilirubin was then conducted. The histopathologic changes of bile duct were observed by HE staining and the ultrastructure of liver cells and surrounding tissues was observed by transmission electron microscopy. Through the above experiments, we found that the change of PKC-α expression may affect the formation process of gallstones. The relationship between PKC-α and ABCB11 was further verified by in vitro and in vivo experiments. Our results suggest that ABCB11 and PKC-α are co-expressed in the tubule membrane of hepatocytes and interact with each other in hepatocytes. The high cholesterol diet further enhances the activation of PKC-α and thus reduces the expression of ABCB11. The formation of cholesterol stones is associated with the down-regulation of ABCB11 expression in the tubule membrane of hepatocytes due to kinase signaling. This is the first study to demonstrate that sphincter of Oddi dysfunction induces gallstones through PKC-α inhibition of ABCB11 expression.
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Affiliation(s)
- Lichao Zhu
- Department of Pediatric Surgery, Shandong Provincial Hospital, Shandong University , Jinan, 250021, China
| | - Wei Su
- Liver Gall Bladder and Pancreatic Surgery Ward, Qinghai Red Cross Hospital, Xining, 810001, China
| | - Xianwen Xu
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Shuai Shao
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Chuan Qin
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong University, 250021, Jinan, China
| | - Ruxin Gao
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Xinxing Wang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Mingze Ma
- Departments of Infectious Diseases, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Junlin Gao
- Liver Gall Bladder and Pancreatic Surgery Ward, Qinghai Red Cross Hospital, Xining, 810001, China.
| | - Zhenhai Zhang
- Department of Hepatobiliary Surgery, Shandong Provincial Hospital, Shandong University, 250021, Jinan, China.
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Johkura K, Usuda N, Tanaka Y, Fukasawa M, Murata K, Noda T, Ohno N. OUP accepted manuscript. Microscopy (Oxf) 2022; 71:262-270. [PMID: 35535544 PMCID: PMC9535788 DOI: 10.1093/jmicro/dfac024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/25/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Kohei Johkura
- Department of Histology and Embryology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - Nobuteru Usuda
- *To whom correspondence should be addressed. E-mail: (N.U.); (N.O.)
| | - Yoshihiro Tanaka
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Motoaki Fukasawa
- Department of Biomedical Molecular Sciences (Anatomy II), Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences, National Institutes of Natural Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Toru Noda
- Department of Occupational Therapy (Anatomy), Biwako Professional University of Rehabilitation, 967 Kitasakacho, Higashiomi, Shiga 527-0145, Japan
- Department of Cell Biology and Anatomy, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Nobuhiko Ohno
- *To whom correspondence should be addressed. E-mail: (N.U.); (N.O.)
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Ren T, Pang L, Dai W, Wu S, Kong J. Regulatory mechanisms of the bile salt export pump (BSEP/ABCB11) and its role in related diseases. Clin Res Hepatol Gastroenterol 2021; 45:101641. [PMID: 33581308 DOI: 10.1016/j.clinre.2021.101641] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/03/2021] [Accepted: 01/21/2021] [Indexed: 02/04/2023]
Abstract
The bile salt export pump (BSEP/ABCB11) is located on the apical membrane and mediates the secretion of bile salts from hepatocytes into the bile. BSEP-mediated bile salt efflux is the rate-limiting step of bile salt secretion and the main driving force of bile flow. BSEP drives and maintains the enterohepatic circulation of bile salts. In recent years, research efforts have been focused on understanding the physiological and pathological functions and regulatory mechanisms of BSEP. These studies elucidated the roles of farnesoid X receptor (FXR), AMP-activated protein kinase (AMPK), liver receptor homolog-1(LRH-1) and nuclear factor erythroid 2-related factor 2 (Nrf-2) in BSEP expression and discovered some regulatory factors which participate in its post-transcriptional regulation. A series of liver diseases have also been shown to be related to BSEP expression and dysfunction, such as cholestasis, drug-induced liver injury, and gallstones. Here, we systematically review and summarize recent literature on BSEP structure, physiological functions, regulatory mechanisms, and related diseases.
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Affiliation(s)
- Tengqi Ren
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Liwei Pang
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Wanlin Dai
- Innovation Institute of China Medical University, Shenyang, Liaoning, China
| | - Shuodong Wu
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China
| | - Jing Kong
- Department of General Surgery, Shengjing Hospital of China Medical University, Shenyang, Liaoning, China.
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Hepatic bile acid transport increases in the postprandial state: A functional 11C-CSar PET/CT study in healthy humans. JHEP Rep 2021; 3:100288. [PMID: 34095797 PMCID: PMC8165435 DOI: 10.1016/j.jhepr.2021.100288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 12/22/2022] Open
Abstract
Background & Aims It is not known how hepatic bile acids transport kinetics changes postprandially in the intact liver. We used positron emission tomography (PET)/computed tomography (CT) with the tracer [N-methyl-11C]cholylsarcosine (11C-CSar), a synthetic sarcosine conjugate of cholic acid, to quantify fasting and postprandial hepatic bile acid transport kinetics in healthy human participants. Methods Six healthy human participants underwent dynamic liver 11C-CSar PET/CT (60 min) during fasting and from 15 min after ingestion of a standard liquid meal. Hepatobiliary secretion kinetics of 11C-CSar was calculated from PET data, blood samples (arterial and hepatic venous) and hepatic blood flow measured using indocyanine green infusion. Results In the postprandial state, hepatic blood perfusion increased on average by 30% (p <0.01), and the flow-independent hepatic intrinsic clearance of 11C-CSar from blood into bile increased by 17% from 1.82 (range, 1.59–2.05) to 2.13 (range, 1.75–2.50) ml blood/min/ml liver tissue (p = 0.042). The increased intrinsic clearance of 11C-CSar was not caused by changes in the basolateral clearance efficacy of 11C-CSar but rather by an upregulated apical transport, as shown by an increase in the rate constant for apical secretion of 11C-CSar from hepatocyte to bile from 0.40 (0.25–0.54) min−1 to 0.67 (0.36–0.98) min−1 (p = 0.03). This resulted in a 33% increase in the intrahepatic bile flow (p = 0.03). Conclusions The rate constant for the transport of bile acids from hepatocytes into biliary canaliculi and the bile flow increased significantly in the postprandial state. This reduced the mean 11C-CSar residence time in the hepatocytes. Lay summary Bile acids are important for digestion of dietary lipids including vitamins. We examined how the secretion of bile acids by the liver into the intestines changes after a standard liquid meal. The transport of bile acids from liver cells into bile and bile flow was increased after the meal. Following a meal, the active transport of bile acids from hepatocytes into bile is increased significantly. A meal also increases bile flow out of the liver. The postprandial changes are induced shortly after intake of a meal.
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Molecular Regulation of Canalicular ABC Transporters. Int J Mol Sci 2021; 22:ijms22042113. [PMID: 33672718 PMCID: PMC7924332 DOI: 10.3390/ijms22042113] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 12/17/2022] Open
Abstract
The ATP-binding cassette (ABC) transporters expressed at the canalicular membrane of hepatocytes mediate the secretion of several compounds into the bile canaliculi and therefore play a key role in bile secretion. Among these transporters, ABCB11 secretes bile acids, ABCB4 translocates phosphatidylcholine and ABCG5/G8 is responsible for cholesterol secretion, while ABCB1 and ABCC2 transport a variety of drugs and other compounds. The dysfunction of these transporters leads to severe, rare, evolutionary biliary diseases. The development of new therapies for patients with these diseases requires a deep understanding of the biology of these transporters. In this review, we report the current knowledge regarding the regulation of canalicular ABC transporters' folding, trafficking, membrane stability and function, and we highlight the role of molecular partners in these regulating mechanisms.
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A Link between Intrahepatic Cholestasis and Genetic Variations in Intracellular Trafficking Regulators. BIOLOGY 2021; 10:biology10020119. [PMID: 33557414 PMCID: PMC7914782 DOI: 10.3390/biology10020119] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 12/20/2022]
Abstract
Simple Summary Cholestasis refers to a medical condition in which the liver is not capable of secreting bile. The consequent accumulation of toxic bile components in the liver leads to liver failure. Cholestasis can be caused by mutations in genes that code for proteins involved in bile secretion. Recently mutations in other genes have been discovered in patients with cholestasis of unknown origin. Interestingly, many of these newly discovered genes code for proteins that regulate the intracellular distribution of other proteins, including those involved in bile secretion. This group of genes thus suggests the deregulated intracellular distribution of bile-secreting proteins as an important but still poorly understood mechanism that underlies cholestasis. To expedite a better understanding of this mechanism, we have reviewed these genes and their mutations and we discuss these in the context of cholestasis. Abstract Intrahepatic cholestasis is characterized by the accumulation of compounds in the serum that are normally secreted by hepatocytes into the bile. Genes associated with familial intrahepatic cholestasis (FIC) include ATP8B1 (FIC1), ABCB11 (FIC2), ABCB4 (FIC3), TJP2 (FIC4), NR1H4 (FIC5) and MYO5B (FIC6). With advanced genome sequencing methodologies, additional mutated genes are rapidly identified in patients presenting with idiopathic FIC. Notably, several of these genes, VPS33B, VIPAS39, SCYL1, and AP1S1, together with MYO5B, are functionally associated with recycling endosomes and/or the Golgi apparatus. These are components of a complex process that controls the sorting and trafficking of proteins, including those involved in bile secretion. These gene variants therefore suggest that defects in intracellular trafficking take a prominent place in FIC. Here we review these FIC-associated trafficking genes and their variants, their contribution to biliary transporter and canalicular protein trafficking, and, when perturbed, to cholestatic liver disease. Published variants for each of these genes have been summarized in table format, providing a convenient reference for those who work in the intrahepatic cholestasis field.
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Sohail MI, Dönmez-Cakil Y, Szöllősi D, Stockner T, Chiba P. The Bile Salt Export Pump: Molecular Structure, Study Models and Small-Molecule Drugs for the Treatment of Inherited BSEP Deficiencies. Int J Mol Sci 2021; 22:E784. [PMID: 33466755 PMCID: PMC7830293 DOI: 10.3390/ijms22020784] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 02/07/2023] Open
Abstract
The bile salt export pump (BSEP/ABCB11) is responsible for the transport of bile salts from hepatocytes into bile canaliculi. Malfunction of this transporter results in progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2) and intrahepatic cholestasis of pregnancy (ICP). Over the past few years, several small molecular weight compounds have been identified, which hold the potential to treat these genetic diseases (chaperones and potentiators). As the treatment response is mutation-specific, genetic analysis of the patients and their families is required. Furthermore, some of the mutations are refractory to therapy, with the only remaining treatment option being liver transplantation. In this review, we will focus on the molecular structure of ABCB11, reported mutations involved in cholestasis and current treatment options for inherited BSEP deficiencies.
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Affiliation(s)
| | - Yaprak Dönmez-Cakil
- Department of Histology and Embryology, Faculty of Medicine, Maltepe University, Maltepe, 34857 Istanbul, Turkey;
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, 13A, 1090 Vienna, Austria;
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse, 13A, 1090 Vienna, Austria;
| | - Peter Chiba
- Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Medical University of Vienna, Waehringerstrasse, 10, 1090 Vienna, Austria
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Engin A. Bile Acid Toxicity and Protein Kinases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1275:229-258. [PMID: 33539018 DOI: 10.1007/978-3-030-49844-3_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
If the bile acids reach to pathological concentrations due to cholestasis, accumulation of hydrophobic bile acids within the hepatocyte may result in cell death. Thus, hydrophobic bile acids induce apoptosis in hepatocytes, while hydrophilic bile acids increase intracellular adenosine 3',5'-monophosphate (cAMP) levels and activate mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways to protect hepatocytes from apoptosis.Two apoptotic pathways have been described in bile acids-induced death. Both are controlled by multiple protein kinase signaling pathways. In mitochondria-controlled pathway, caspase-8 is activated with death domain-independent manner, whereas, Fas-dependent classical pathway involves ligand-independent oligomerization of Fas.Hydrophobic bile acids dose-dependently upregulate the inflammatory response by further stimulating production of inflammatory cytokines. Death receptor-mediated apoptosis is regulated at the cell surface by the receptor expression, at the death-inducing signaling complex (DISC) by expression of procaspase-8, the death receptors Fas-associated death domain (FADD), and cellular FADD-like interleukin 1-beta (IL-1β)-converting enzyme (FLICE) inhibitory protein (cFLIP). Bile acids prevent cFLIP recruitment to the DISC and thereby enhance initiator caspase activation and lead to cholestatic apoptosis. At mitochondria, the expression of B-cell leukemia/lymphoma-2 (Bcl-2) family proteins contribute to apoptosis by regulating mitochondrial cytochrome c release via Bcl-2, Bcl-2 homology 3 (BH3) interacting domain death agonist (Bid), or Bcl-2 associated protein x (Bax). Fas receptor CD95 activation by hydrophobic bile acids is initiated by reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) signaling. However, activation of necroptosis by ligands of death receptors requires the kinase activity of receptor interacting protein1 (RIP1), which mediates the activation of RIP3 and mixed lineage kinase domain-like protein (MLKL). In this chapter, mainly the effect of protein kinases signal transduction on the mechanisms of hydrophobic bile acids-induced inflammation, apoptosis, necroptosis and necrosis are discussed.
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Affiliation(s)
- Atilla Engin
- Department of General Surgery, Faculty of Medicine, Gazi University, Ankara, Turkey.
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Kroll T, Prescher M, Smits SHJ, Schmitt L. Structure and Function of Hepatobiliary ATP Binding Cassette Transporters. Chem Rev 2020; 121:5240-5288. [PMID: 33201677 DOI: 10.1021/acs.chemrev.0c00659] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The liver is beyond any doubt the most important metabolic organ of the human body. This function requires an intensive crosstalk within liver cellular structures, but also with other organs. Membrane transport proteins are therefore of upmost importance as they represent the sensors and mediators that shuttle signals from outside to the inside of liver cells and/or vice versa. In this review, we summarize the known literature of liver transport proteins with a clear emphasis on functional and structural information on ATP binding cassette (ABC) transporters, which are expressed in the human liver. These primary active membrane transporters form one of the largest families of membrane proteins. In the liver, they play an essential role in for example bile formation or xenobiotic export. Our review provides a state of the art and comprehensive summary of the current knowledge of hepatobiliary ABC transporters. Clearly, our knowledge has improved with a breath-taking speed over the last few years and will expand further. Thus, this review will provide the status quo and will lay the foundation for new and exciting avenues in liver membrane transporter research.
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Affiliation(s)
- Tim Kroll
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Martin Prescher
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.,Center for Structural Studies, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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Garzel B, Zhang L, Huang SM, Wang H. A Change in Bile Flow: Looking Beyond Transporter Inhibition in the Development of Drug-induced Cholestasis. Curr Drug Metab 2020; 20:621-632. [PMID: 31288715 DOI: 10.2174/1389200220666190709170256] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/22/2019] [Accepted: 06/12/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Drug-induced Liver Injury (DILI) has received increasing attention over the past decades, as it represents the leading cause of drug failure and attrition. One of the most prevalent and severe forms of DILI involves the toxic accumulation of bile acids in the liver, known as Drug-induced Cholestasis (DIC). Traditionally, DIC is studied by exploring the inhibition of hepatic transporters such as Bile Salt Export Pump (BSEP) and multidrug resistance-associated proteins, predominantly through vesicular transport assays. Although this approach has identified numerous drugs that alter bile flow, many DIC drugs do not demonstrate prototypical transporter inhibition, but rather are associated with alternative mechanisms. METHODS We undertook a focused literature search on DIC and biliary transporters and analyzed peer-reviewed publications over the past two decades or so. RESULTS We have summarized the current perception regarding DIC, biliary transporters, and transcriptional regulation of bile acid homeostasis. A growing body of literature aimed to identify alternative mechanisms in the development of DIC has been evaluated. This review also highlights current in vitro approaches used for prediction of DIC. CONCLUSION Efforts have continued to focus on BSEP, as it is the primary route for hepatic biliary clearance. In addition to inhibition, drug-induced BSEP repression or the combination of these two has emerged as important alternative mechanisms leading to DIC. Furthermore, there has been an evolution in the approaches to studying DIC including 3D cell cultures and computational modeling.
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Affiliation(s)
- Brandy Garzel
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, United States.,Becton Dickinson, 54 Loveton Circle, Sparks, MD 21152, United States
| | - Lei Zhang
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, United States.,Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research, FDA, Silver Spring, MD 20993, United States
| | - Shiew-Mei Huang
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, United States
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States
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Lu X, Liu L, Shan W, Kong L, Chen N, Lou Y, Zeng S. The Role of the Sodium-taurocholate Co-transporting Polypeptide (NTCP) and Bile Salt Export Pump (BSEP) in Related Liver Disease. Curr Drug Metab 2019; 20:377-389. [PMID: 31258056 DOI: 10.2174/1389200220666190426152830] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 03/10/2019] [Accepted: 03/26/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Sodium Taurocholate Co-transporting Polypeptide (NTCP) and Bile Salt Export Pump (BSEP) play significant roles as membrane transporters because of their presence in the enterohepatic circulation of bile salts. They have emerged as promising drug targets in related liver disease. METHODS We reviewed the literature published over the last 20 years with a focus on NTCP and BSEP. RESULTS This review summarizes the current perception about structure, function, genetic variation, and regulation of NTCP and BSEP, highlights the effects of their defects in some hepatic disorders, and discusses the application prospect of new transcriptional activators in liver diseases. CONCLUSION NTCP and BSEP are important proteins for transportation and homeostasis maintenance of bile acids. Further research is needed to develop new models for determining the structure-function relationship of bile acid transporters and screening for substrates and inhibitors, as well as to gain more information about the regulatory genetic mechanisms involved in the processes of liver injury.
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Affiliation(s)
- Xiaoyang Lu
- The First Affiliated Hospital, Zhejiang University, Zhejiang, China
| | - Lin Liu
- The First Affiliated Hospital, Zhejiang University, Zhejiang, China
| | - Wenya Shan
- The First Affiliated Hospital, Zhejiang University, Zhejiang, China
| | - Limin Kong
- The First Affiliated Hospital, Zhejiang University, Zhejiang, China
| | - Na Chen
- The First Affiliated Hospital, Zhejiang University, Zhejiang, China
| | - Yan Lou
- The First Affiliated Hospital, Zhejiang University, Zhejiang, 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, Zhejiang, China
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Anticholestatic mechanisms of ursodeoxycholic acid in lipopolysaccharide-induced cholestasis. Biochem Pharmacol 2019; 168:48-56. [DOI: 10.1016/j.bcp.2019.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022]
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Roma MG, Barosso IR, Miszczuk GS, Crocenzi FA, Pozzi EJS. Dynamic Localization of Hepatocellular Transporters: Role in Biliary Excretion and Impairment in Cholestasis. Curr Med Chem 2019; 26:1113-1154. [DOI: 10.2174/0929867325666171205153204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 12/25/2022]
Abstract
Bile flow generation is driven by the vectorial transfer of osmotically active compounds from sinusoidal blood into a confined space, the bile canaliculus. Hence, localization of hepatocellular transporters relevant to bile formation is crucial for bile secretion. Hepatocellular transporters are localized either in the plasma membrane or in recycling endosomes, from where they can be relocated to the plasma membrane on demand, or endocytosed when the demand decreases. The balance between endocytic internalization/ exocytic targeting to/from this recycling compartment is therefore the main determinant of the hepatic capability to generate bile, and to dispose endo- and xenobiotics. Furthermore, the exacerbated endocytic internalization is a common pathomechanisms in both experimental and human cholestasis; this results in bile secretory failure and, eventually, posttranslational transporter downregulation by increased degradation. This review summarizes the proposed structural mechanisms accounting for this pathological condition (e.g., alteration of function, localization or expression of F-actin or F-actin/transporter cross-linking proteins, and switch to membrane microdomains where they can be readily endocytosed), and the mediators implicated (e.g., triggering of “cholestatic” signaling transduction pathways). Lastly, we discussed the efficacy to counteract the cholestatic failure induced by transporter internalization of a number of therapeutic experimental approaches based upon the use of compounds that trigger exocytic targetting of canalicular transporters (e.g., cAMP, tauroursodeoxycholate). This therapeutics may complement treatments aimed to transcriptionally improve transporter expression, by affording proper localization and membrane stability to the de novo synthesized transporters.
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Affiliation(s)
- Marcelo G. Roma
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Ismael R. Barosso
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Gisel S. Miszczuk
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Fernando A. Crocenzi
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
| | - Enrique J. Sánchez Pozzi
- Instituto de Fisiologia Experimental (IFISE) - Facultad de Ciencias Bioquimicas y Farmaceuticas (CONICET - U.N.R.), S2002LRL, Rosario, Argentina
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Malinen MM, Ito K, Kang HE, Honkakoski P, Brouwer KLR. Protein expression and function of organic anion transporters in short-term and long-term cultures of Huh7 human hepatoma cells. Eur J Pharm Sci 2019; 130:186-195. [PMID: 30685239 DOI: 10.1016/j.ejps.2019.01.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 12/11/2022]
Abstract
Human-derived hepatic cell lines are a valuable alternative to primary hepatocytes for drug metabolism, transport and toxicity studies. However, their relevance for investigations of drug-drug and drug-organic anion (e.g., bile acid, steroid hormone) interactions at the transporter level remains to be established. The aim of the present study was to determine the suitability of the Huh7 cell line for transporter-dependent experiments. Huh7 cells were cultured for 1 to 4 weeks and subsequently were analyzed for protein expression, localization and activity of solute carrier (SLC) and ATP-binding cassette (ABC) transporters involved in organic anion transport using liquid chromatography-tandem mass spectroscopy, immunocytochemistry, and model substrates [3H]taurocholate (TCA), [3H]dehydroepiandrosterone sulfate (DHEAS) and 5(6)-carboxy-2',7'-dichlorofluorescein (CDF) diacetate. The extended 4-week culture resulted in a phenotype resembling primary hepatocytes and differentiated HepaRG cells: cuboidal hepatocyte-like cells with elongated bile canaliculi-like structures were surrounded by epithelium-like cells. Protein expression of OSTα, OSTβ and OATP1B3 increased over time. Moreover, the uptake of the SLC probe substrate DHEAS was higher in 4-week than in 1-week Huh7 cultures. NTCP, OATP1B1, BSEP and MRP3 were barely or not detectable in Huh7 cells. OATP2B1, MRP2 and MRP4 protein expression remained at similar levels over the four weeks of culture. The activity of MRP2 and the formation of bile canaliculi-like structures were confirmed by accumulation of CDF in the intercellular compartments. Results indicate that along with morphological maturation, transporters responsible for alternative bile acid secretion pathways are expressed and active in long-term cultures of Huh7 cells, suggesting that differentiated Huh7 cells may be suitable for studying the function and regulation of these organic anion transporters.
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Affiliation(s)
- Melina M Malinen
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
| | - Katsuaki Ito
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; DMPK Research Department, Teijin Pharma Limited, Hino, Tokyo, Japan.
| | - Hee Eun Kang
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, South Korea.
| | - Paavo Honkakoski
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
| | - Kim L R Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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15
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Park SW, Webster CRL, Anwer MS. Mechanism of inhibition of taurolithocholate-induced retrieval of plasma membrane MRP2 by cyclic AMP and tauroursodeoxycholate. Physiol Rep 2018; 5. [PMID: 29192063 PMCID: PMC5727282 DOI: 10.14814/phy2.13529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 12/26/2022] Open
Abstract
Taurolithocholate (TLC) produces cholestasis by inhibiting biliary solute secretion in part by retrieving MRP2 from the plasma membrane (PM). Tauroursodeoxycholate (TUDC) and cAMP reverse TLC‐induced cholestasis by inhibiting TLC‐induced retrieval of MRP2. However, cellular mechanisms for this reversal are incompletely understood. Recently, we reported that TLC decreases PM‐MRP2 by activating PKCε followed by phosphorylation of myristoylated alanine‐rich C kinase substrate (MARCKS). Thus, cAMP and TUDC may reverse TLC‐induced cholestasis by inhibiting the TLC/PKCε/MARCKS phosphorylation pathway. We tested this hypothesis by determining whether TUDC and/or cAMP inhibit TLC‐induced activation of PKCε and phosphorylation of MARCKS. Studies were conducted in HuH‐NTCP cell line and rat hepatocytes. Activation of PKCε was determined from the translocation of PKCε to PM using a biotinylation method. Phosphorylation of MARCKS was determined by immunoblotting with a phospho‐MARCKS antibody. TLC, but not cAMP and TUDC, activated PKCε and increased MARCKS phosphorylation in HuH‐NTCP as well in rat hepatocytes. Treatment with TUDC or cAMP inhibited TLC‐induced activation of PKCε and increases in MARCKS phosphorylation in both cell types. Based on these results, we conclude that the reversal of TLC‐induced cholestasis by cAMP and TUDC involves, at least in part, inhibition of TLC‐mediated activation of the PKCε/MARCKS phosphorylation pathway.
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Affiliation(s)
- Se Won Park
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, Massachusetts, USA
| | - Cynthia R L Webster
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, Massachusetts, USA
| | - Mohammed S Anwer
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, Massachusetts, USA
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16
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Nakano T, Moriya K, Koike K, Horie T. Hepatitis C virus core protein triggers abnormal porphyrin metabolism in human hepatocellular carcinoma cells. PLoS One 2018; 13:e0198345. [PMID: 29856826 PMCID: PMC5983478 DOI: 10.1371/journal.pone.0198345] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/17/2018] [Indexed: 12/23/2022] Open
Abstract
Porphyria cutanea tarda (PCT), the most common of the human porphyrias, arises from a deficiency of uroporphyrinogen decarboxylase. Studies have shown a high prevalence of hepatitis C virus (HCV) infection in patients with PCT. While these observations implicate HCV infection as a risk factor for PCT pathogenesis, the mechanism of interaction between the virus and porphyrin metabolism is unknown. This study aimed to assess the effect of HCV core protein on intracellular porphyrin metabolism to elucidate the link between HCV infection and PCT. The accumulation and excretion of porphyrins after treatment with 5-aminolevulinic acid, a porphyrin precursor, were compared between cells stably expressing HCV core protein and controls. Cells expressing HCV core protein had lower amounts of intracellular protoporphyrin IX and heme and had higher amounts of excreted coproporphyrin III, the oxidized form of coproporphyrinogen III, compared with controls. These observations suggest that HCV core protein affects porphyrin metabolism and facilitates the export of excess coproporphyrinogen III and/or coproporphyrin III, possibly via porphyrin transporters. Real-time PCR analysis revealed that the presence of HCV core protein increased the mRNA expression of porphyrin exporters ABCG2 and FLVCR1. Western blot analysis showed a higher expression level of FLVCR1, but not ABCG2, as well as a higher expression level of mature ALAS1, which is the rate-limiting enzyme in the heme synthesis pathway, in HCV core protein-expressing cells compared with controls. The data indicate that HCV core protein induced abnormal intracellular porphyrin metabolism, with an over-excretion of coproporphyrin III. These findings may partially account for the susceptibility of HCV-infected individuals to PCT development.
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Affiliation(s)
- Takafumi Nakano
- Biopharmaceutics and Molecular Toxicology Unit, Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Nakano-ku, Tokyo, Japan
- * E-mail:
| | - Kyoji Moriya
- Department of Internal Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kazuhiko Koike
- Department of Internal Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Toshiharu Horie
- Biopharmaceutics and Molecular Toxicology Unit, Faculty of Pharmaceutical Sciences, Teikyo Heisei University, Nakano-ku, Tokyo, Japan
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17
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Li J, Dawson PA. Animal models to study bile acid metabolism. Biochim Biophys Acta Mol Basis Dis 2018; 1865:895-911. [PMID: 29782919 DOI: 10.1016/j.bbadis.2018.05.011] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 12/19/2022]
Abstract
The use of animal models, particularly genetically modified mice, continues to play a critical role in studying the relationship between bile acid metabolism and human liver disease. Over the past 20 years, these studies have been instrumental in elucidating the major pathways responsible for bile acid biosynthesis and enterohepatic cycling, and the molecular mechanisms regulating those pathways. This work also revealed bile acid differences between species, particularly in the composition, physicochemical properties, and signaling potential of the bile acid pool. These species differences may limit the ability to translate findings regarding bile acid-related disease processes from mice to humans. In this review, we focus primarily on mouse models and also briefly discuss dietary or surgical models commonly used to study the basic mechanisms underlying bile acid metabolism. Important phenotypic species differences in bile acid metabolism between mice and humans are highlighted.
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Affiliation(s)
- Jianing Li
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322, United States
| | - Paul A Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322, United States.
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18
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Notenboom S, Weigand KM, Proost JH, van Lipzig MM, van de Steeg E, van den Broek PH, Greupink R, Russel FG, Groothuis GM. Development of a mechanistic biokinetic model for hepatic bile acid handling to predict possible cholestatic effects of drugs. Eur J Pharm Sci 2018; 115:175-184. [DOI: 10.1016/j.ejps.2018.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 12/04/2017] [Accepted: 01/03/2018] [Indexed: 10/18/2022]
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19
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Ortega B, Dey JM, Gardella AR, Proano J, Vaneerde D. Antibody-mediated inhibition of EGFR reduces phosphate excretion and induces hyperphosphatemia and mild hypomagnesemia in mice. Physiol Rep 2017; 5:5/5/e13176. [PMID: 28292888 PMCID: PMC5350180 DOI: 10.14814/phy2.13176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/30/2017] [Indexed: 02/07/2023] Open
Abstract
Monoclonal antibody therapies targeting the EGF receptor (EGFR) frequently result in hypomagnesemia in human patients. In contrast, EGFR tyrosine kinase inhibitors do not affect Mg2+ balance in patients and only have a mild effect on Mg2+ homeostasis in rodents at elevated doses. EGF has also been shown to affect phosphate (Pi) transport in rat and rabbit proximal convoluted tubules (PCT), but evidence from studies targeting EGFR and looking at Pi excretion in whole animals is still missing. Thus, the role of EGF in regulating reabsorption of Mg2+ and/or Pi in the kidney remains controversial. Here, we inject mice with the anti-EGFR monoclonal antibody ME-1 for 2 weeks and observe a significant increase in serum Pi and mild hypomagnesemia, but no changes in Pi or Mg2+ excretion. In contrast, a single injection of ME-1 resulted in hyperphosphatemia and a significant reduction in Pi excretion 2 days after treatment, while no changes in serum Mg2+ or Mg2+ excretion were observed. Dietary Mg2+ deprivation is known to trigger a rapid Mg2+ conservation response in addition to hyperphosphatemia and hyperphosphaturia. Interestingly, one dose of ME-1 did not significantly modify the response of mice to 2 days of Mg2+ deprivation. These data show that EGFR plays a significant role in regulating Pi reabsorption in the kidney PCT, but suggest only a minor role in long-term regulation of Mg2+ transport in the distal convoluted tubule.
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Affiliation(s)
- Bernardo Ortega
- Department of Biology, The College at Brockport State University of New York, Brockport, New York
| | - Jason M Dey
- Department of Biology, The College at Brockport State University of New York, Brockport, New York
| | - Allison R Gardella
- Department of Biology, The College at Brockport State University of New York, Brockport, New York
| | - Jacob Proano
- Department of Biology, The College at Brockport State University of New York, Brockport, New York
| | - Deanna Vaneerde
- Department of Biology, The College at Brockport State University of New York, Brockport, New York
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20
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SARNOVA L, GREGOR M. Biliary System Architecture: Experimental Models and Visualization Techniques. Physiol Res 2017; 66:383-390. [DOI: 10.33549/physiolres.933499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The complex architecture of the liver biliary network represents a structural prerequisite for the formation and secretion of bile as well as excretion of toxic substances through bile ducts. Disorders of the biliary tract affect a significant portion of the worldwide population, often leading to cholestatic liver diseases. Cholestatic liver disease is a condition that results from an impairment of bile formation or bile flow to the gallbladder and duodenum. Cholestasis leads to dramatic changes in biliary tree architecture, worsening liver disease and systemic illness. Recent studies show that the prevalence of cholestatic liver diseases is increasing. The availability of well characterized animal models, as well as development of visualization approaches constitutes a critical asset to develop novel pathogenetic concepts and new treatment strategies.
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Affiliation(s)
| | - M. GREGOR
- Laboratory of Integrative Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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21
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Protein Kinases C-Mediated Regulations of Drug Transporter Activity, Localization and Expression. Int J Mol Sci 2017; 18:ijms18040764. [PMID: 28375174 PMCID: PMC5412348 DOI: 10.3390/ijms18040764] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 01/05/2023] Open
Abstract
Drug transporters are now recognized as major actors in pharmacokinetics, involved notably in drug–drug interactions and drug adverse effects. Factors that govern their activity, localization and expression are therefore important to consider. In the present review, the implications of protein kinases C (PKCs) in transporter regulations are summarized and discussed. Both solute carrier (SLC) and ATP-binding cassette (ABC) drug transporters can be regulated by PKCs-related signaling pathways. PKCs thus target activity, membrane localization and/or expression level of major influx and efflux drug transporters, in various normal and pathological types of cells and tissues, often in a PKC isoform-specific manner. PKCs are notably implicated in membrane insertion of bile acid transporters in liver and, in this way, are thought to contribute to cholestatic or choleretic effects of endogenous compounds or drugs. The exact clinical relevance of PKCs-related regulation of drug transporters in terms of drug resistance, pharmacokinetics, drug–drug interactions and drug toxicity remains however to be precisely determined. This issue is likely important to consider in the context of the development of new drugs targeting PKCs-mediated signaling pathways, for treating notably cancers, diabetes or psychiatric disorders.
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22
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Mitogen-activated protein kinases are involved in hepatocanalicular dysfunction and cholestasis induced by oxidative stress. Arch Toxicol 2016; 91:2391-2403. [PMID: 27913845 DOI: 10.1007/s00204-016-1898-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/24/2016] [Indexed: 12/22/2022]
Abstract
In previous studies, we showed that the pro-oxidant model agent tert-butyl hydroperoxide (tBuOOH) induces alterations in hepatocanalicular secretory function by activating Ca2+-dependent protein kinase C isoforms (cPKC), via F-actin disorganization followed by endocytic internalization of canalicular transporters relevant to bile formation (Mrp2, Bsep). Since mitogen-activated protein kinases (MAPKs) may be downstream effectors of cPKC, we investigated here the involvement of the MAPKs of the ERK1/2, JNK1/2, and p38MAPK types in these deleterious effects. tBuOOH (100 µM, 15 min) increased the proportion of the active, phosphorylated forms of ERK1/2, JNK1/2, and p38MAPK, and panspecific PKC inhibition with bisindolylmaleimide-1 (100 nM) or selective cPKC inhibition with Gö6976 (1 μM) prevented the latter two events. In isolated rat hepatocyte couplets, tBuOOH (100 µM, 15 min) decreased the canalicular vacuolar accumulation of the fluorescent Bsep and Mrp2 substrates, cholylglycylamido fluorescein, and glutathione-methylfluorescein, respectively, and selective inhibitors of ERK1/2 (PD098059), JNK1/2 (SP600125), and p38MAPK (SB203580) partially prevented these alterations. In in situ perfused rat livers, these three MAPK inhibitors prevented tBuOOH (75 µM)-induced impairment of bile flow and the decrease in the biliary output of the Bsep and Mrp2 substrates, taurocholate, and dinitrophenyl-S-glutathione, respectively. The changes in Bsep/Mrp2 and F-actin localization induced by tBuOOH, as assessed by (immuno)fluorescence staining followed by analysis of confocal images, were prevented total or partially by the MAPK inhibitors. We concluded that MAPKs of the ERK1/2, JNK1/2, and p38MAPK types are all involved in cholestasis induced by oxidative stress, by promoting F-actin rearrangement and further endocytic internalization of canalicular transporters critical for bile formation.
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23
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Schonhoff CM, Park SW, Webster CR, Anwer MS. p38 MAPK α and β isoforms differentially regulate plasma membrane localization of MRP2. Am J Physiol Gastrointest Liver Physiol 2016; 310:G999-G1005. [PMID: 27012769 PMCID: PMC4935486 DOI: 10.1152/ajpgi.00005.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/14/2016] [Indexed: 01/31/2023]
Abstract
In hepatocytes, cAMP both activates p38 mitogen-activated protein kinase (MAPK) and increases the amount of multidrug resistance-associated protein-2 (MRP2) in the plasma membrane (PM-MRP2). Paradoxically, taurolithocholate (TLC) activates p38 MAPK but decreases PM-MRP2 in hepatocytes. These opposing effects of cAMP and TLC could be mediated via different p38 MAPK isoforms (α and β) that are activated differentially by upstream kinases (MKK3, MKK4, and MKK6). Thus we tested the hypothesis that p38α MAPK and p38β MAPK mediate increases and decreases in PM-MRP2 by cAMP and TLC, respectively. Studies were conducted in hepatocytes isolated from C57BL/6 wild-type (WT) and MKK3-knockout (MKK3(-/-)) mice and in a hepatoma cell line (HuH7) that overexpresses sodium-taurocholate cotransporting polypeptide (NTCP) (HuH-NTCP). Cyclic AMP activated MKK3, p38 MAPK, and p38α MAPK and increased PM-MRP2 in WT hepatocytes, but failed to activate p38α MAPK or increase PM-MRP2 in MKK3(-/-) hepatocytes. In contrast to cAMP, TLC activated total p38 MAPK but decreased PM-MRP2, and did not activate MKK3 or p38α MAPK in WT hepatocytes. In MKK3(-/-) hepatocytes, TLC still decreased PM-MRP2 and activated p38 MAPK, indicating that these effects are not MKK3-dependent. Additionally, TLC activated MKK6 in MKK3(-/-) hepatocytes, and small interfering RNA knockdown of p38β MAPK abrogated TLC-mediated decreases in PM-MRP2 in HuH-NTCP cells. Taken together, these results suggest that p38α MAPK facilitates plasma membrane insertion of MRP2 by cAMP, whereas p38β MAPK mediates retrieval of PM-MRP2 by TLC.
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Affiliation(s)
- Christopher M. Schonhoff
- 1Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| | - Se Won Park
- 1Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
| | - Cynthia R.L. Webster
- 2Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts
| | - M. Sawkat Anwer
- 1Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts; and
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24
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Exon-skipping and mRNA decay in human liver tissue: molecular consequences of pathogenic bile salt export pump mutations. Sci Rep 2016; 6:24827. [PMID: 27114171 PMCID: PMC4845019 DOI: 10.1038/srep24827] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/05/2016] [Indexed: 12/12/2022] Open
Abstract
The bile salt export pump BSEP mediates bile formation. Over 150 BSEP mutations are associated with progressive familial intrahepatic cholestasis type 2 (PFIC-2), with few characterised specifically. We examined liver tissues from two PFIC-2 patients compound heterozygous for the splice-site mutation c.150 + 3A > C and either c.2783_2787dup5 resulting in a frameshift with a premature termination codon (child 1) or p.R832C (child 2). Splicing was analysed with a minigene system and mRNA sequencing from patients’ livers. Protein expression was shown by immunofluorescence. Using the minigene, c.150 + 3A > C causes complete skipping of exon 3. In liver tissue of child 1, c.2783_2787dup5 was found on DNA but not on mRNA level, implying nonsense-mediated mRNA decay (NMD) when c.2783_2787dup5 is present. Still, BSEP protein as well as mRNA with and without exon 3 were detectable and can be assigned to the c.150 + 3A > C allele. Correctly spliced transcripts despite c.150 + 3A > C were also confirmed in liver of child 2. In conclusion, we provide evidence (1) for effective NMD due to a BSEP frameshift mutation and (2) partial exon-skipping due to c.150 + 3A > C. The results illustrate that the extent of exon-skipping depends on the genomic and cellular context and that regulation of splicing may have therapeutic potential.
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25
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Kubitz R, Dröge C, Kluge S, Stross C, Walter N, Keitel V, Häussinger D, Stindt J. Autoimmune BSEP disease: disease recurrence after liver transplantation for progressive familial intrahepatic cholestasis. Clin Rev Allergy Immunol 2016; 48:273-84. [PMID: 25342496 DOI: 10.1007/s12016-014-8457-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Severe cholestasis may result in end-stage liver disease with the need of liver transplantation (LTX). In children, about 10 % of LTX are necessary because of cholestatic liver diseases. Apart from bile duct atresia, three types of progressive familial intrahepatic cholestasis (PFIC) are common causes of severe cholestasis in children. The three subtypes of PFIC are defined by the involved genes: PFIC-1, PFIC-2, and PFIC-3 are due to mutations of P-type ATPase ATP8B1 (familial intrahepatic cholestasis 1, FIC1), the ATP binding cassette transporter ABCB11 (bile salt export pump, BSEP), or ABCB4 (multidrug resistance protein 3, MDR3), respectively. All transporters are localized in the canalicular membrane of hepatocytes and together mediate bile salt and phospholipid transport. In some patients with PFIC-2 disease, recurrence has been observed after LTX, which mimics a PFIC phenotype. It could be shown by several groups that inhibitory anti-BSEP antibodies emerge, which most likely cause disease recurrence. The prevalence of severe BSEP mutations (e.g., splice site and premature stop codon mutations) is very high in this group of patients. These mutations often result in the complete absence of BSEP, which likely accounts for an insufficient auto-tolerance against BSEP. Although many aspects of this "new" disease are not fully elucidated, the possibility of anti-BSEP antibody formation has implications for the pre- and posttransplant management of PFIC-2 patients. This review will summarize the current knowledge including diagnosis, pathomechanisms, and management of "autoimmune BSEP disease."
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Affiliation(s)
- Ralf Kubitz
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany,
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Telbisz Á, Homolya L. Recent advances in the exploration of the bile salt export pump (BSEP/ABCB11) function. Expert Opin Ther Targets 2015; 20:501-14. [PMID: 26573700 DOI: 10.1517/14728222.2016.1102889] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION The bile salt export pump (BSEP/ABCB11), residing in the apical membrane of hepatocyte, mediates the secretion of bile salts into the bile. A range of human diseases is associated with the malfunction of BSEP, including fatal hereditary liver disorders and mild cholestatic conditions. Manifestation of these diseases primarily depends on the mutation type; however, other factors such as hormonal changes and drug interactions can also trigger or influence the related diseases. AREAS COVERED Here, we summarize the recent knowledge on BSEP by covering its transport properties, cellular localization, regulation and major mutations/polymorphisms, as well as the hereditary and acquired diseases associated with BSEP dysfunction. We discuss the different model expression systems employed to understand the function of the BSEP variants, their drug interactions and the contemporary therapeutic interventions. EXPERT OPINION The limitations of the available model expression systems for BSEP result in controversial conclusions, and obstruct our deeper insight into BSEP deficiencies and BSEP-related drug interactions. The knowledge originating from different methodologies, such as clinical studies, molecular genetics, as well as in vitro and in silico modeling, should be integrated and harmonized. Increasing availability of robust molecular biological tools and our better understanding of the mechanism of BSEP deficiencies should make the personalized, mutation-based therapeutic interventions more attainable.
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Affiliation(s)
- Ágnes Telbisz
- a Institute of Enzymology, Research Centre for Natural Sciences , Hungarian Academy of Sciences , Magyar tudósok körútja 2, Budapest 1117 , Hungary
| | - László Homolya
- a Institute of Enzymology, Research Centre for Natural Sciences , Hungarian Academy of Sciences , Magyar tudósok körútja 2, Budapest 1117 , Hungary
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27
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Varma S, Revencu N, Stephenne X, Scheers I, Smets F, Beleza-Meireles A, Reding R, Roskams T, Sokal EM. Retargeting of bile salt export pump and favorable outcome in children with progressive familial intrahepatic cholestasis type 2. Hepatology 2015; 62:198-206. [PMID: 25847299 DOI: 10.1002/hep.27834] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/30/2015] [Indexed: 12/24/2022]
Abstract
UNLABELLED We investigated predictors of clinical evolution in progressive familial intrahepatic cholestasis type 2 patients and how they relate to bile salt export pump (BSEP) expression and its (re)targeting. Our retrospective study included 22 children with progressive familial intrahepatic cholestasis type 2. Clinical, biochemical, and histological characteristics were reviewed on admittance and following treatment with either ursodeoxycholic acid alone (10 mg/kg thrice daily, n = 19) or partial biliary diversion (n = 3). Immunostaining of BSEP was performed in 20 patients. Response to treatment was defined as normalization of pruritus, disappearance of jaundice, and alanine aminotransferase (ALT) levels <1.5 times the upper limit of normal. Ten of 22 patients were responders, and paired biopsies were available in six. De novo or retargeted canalicular expression of BSEP occurred in four of these six, two of whom exhibited baseline intracellular expression. Twelve of 22 were nonresponders and exhibited earlier onset of jaundice (<9 months), neonatal cholestasis, and higher ALT levels. An ALT >165 IU/L produced 72% sensitivity and 55% specificity in predicting nonresponse. Seven patients were still responding at last follow-up (median = 20 months, range 5-67 months). Three responders relapsed after 56, 72, and 82 months, respectively. Of nine surviving responders, median relapse-free survival time was 72 months (95% confidence interval 48-96 months) and 5-year relapse-free survival was 75% (95% confidence interval 33-100%). Intracellular BSEP at baseline was seen in six, of whom five were responders. Genetic analysis was performed in 17 of 22, confirming diagnosis in 13 (76%) and in four (24%) in whom only heterozygous mutation was identified. CONCLUSION De novo or retargeted canalicular expression of BSEP occurs in treatment responders; children with late-onset presentation, lower ALT, and intracellular BSEP expression are likely to respond, at least transiently, to nontransplant treatment.
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Affiliation(s)
- Sharat Varma
- Service de Gastroentérologie et Hépatologie Pédiatrique
| | | | | | | | | | | | - Raymond Reding
- Unités de Chirurgie Pédiatrique, Université Catholique de Louvain, Cliniques Universitaires St. Luc, Brussels, Belgium
| | - Tania Roskams
- Katholiek Universiteit Leuven, University Hospital Gasthuisberg, Leuven, Belgium
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28
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Kluth M, Stindt J, Dröge C, Linnemann D, Kubitz R, Schmitt L. A mutation within the extended X loop abolished substrate-induced ATPase activity of the human liver ATP-binding cassette (ABC) transporter MDR3. J Biol Chem 2014; 290:4896-4907. [PMID: 25533467 DOI: 10.1074/jbc.m114.588566] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The human multidrug resistance protein 3 (MDR3/ABCB4) belongs to the ubiquitous family of ATP-binding cassette (ABC) transporters and is located in the canalicular membrane of hepatocytes. There it flops the phospholipids of the phosphatidylcholine (PC) family from the inner to the outer leaflet. Here, we report the characterization of wild type MDR3 and the Q1174E mutant, which was identified previously in a patient with progressive familial intrahepatic cholestasis type 3 (PFIC-3). We expressed different variants of MDR3 in the yeast Pichia pastoris, purified the proteins via tandem affinity chromatography, and determined MDR3-specific ATPase activity in the presence or absence of phospholipids. The ATPase activity of wild type MDR3 was stimulated 2-fold by liver PC or 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine lipids. Furthermore, the cross-linking of MDR3 with a thiol-reactive fluorophore blocked ATP hydrolysis and exhibited no PC stimulation. Similarly, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin lipids did not induce an increase of wild type MDR3 ATPase activity. The phosphate analogues beryllium fluoride and aluminum fluoride led to complete inhibition of ATPase activity, whereas orthovanadate inhibited exclusively the PC-stimulated ATPase activity of MDR3. The Q1174E mutation is located in the nucleotide-binding domain in direct proximity of the leucine of the ABC signature motif and extended the X loop, which is found in ABC exporters. Our data on the Q1174E mutant demonstrated basal ATPase activity, but PC lipids were incapable of stimulating ATPase activity highlighting the role of the extended X loop in the cross-talk of the nucleotide-binding domain and the transmembrane domain.
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Affiliation(s)
- Marianne Kluth
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf
| | - Jan Stindt
- Department of Gastroenterology, Hepatology and Infectiology, University Hospital, 40225 Düsseldorf
| | - Carola Dröge
- Department of Gastroenterology, Hepatology and Infectiology, University Hospital, 40225 Düsseldorf
| | - Doris Linnemann
- Department of Gastroenterology, Hepatology and Infectiology, University Hospital, 40225 Düsseldorf
| | - Ralf Kubitz
- Department of Gastroenterology, Hepatology and Infectiology, University Hospital, 40225 Düsseldorf
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf; Cluster of Excellence on Plant Sciences, Heinrich Heine University, 40225 Düsseldorf, Germany.
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29
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Demetz E, Schroll A, Auer K, Heim C, Patsch JR, Eller P, Theurl M, Theurl I, Theurl M, Seifert M, Lener D, Stanzl U, Haschka D, Asshoff M, Dichtl S, Nairz M, Huber E, Stadlinger M, Moschen AR, Li X, Pallweber P, Scharnagl H, Stojakovic T, März W, Kleber ME, Garlaschelli K, Uboldi P, Catapano AL, Stellaard F, Rudling M, Kuba K, Imai Y, Arita M, Schuetz JD, Pramstaller PP, Tietge UJF, Trauner M, Norata GD, Claudel T, Hicks AA, Weiss G, Tancevski I. The arachidonic acid metabolome serves as a conserved regulator of cholesterol metabolism. Cell Metab 2014; 20:787-798. [PMID: 25444678 PMCID: PMC4232508 DOI: 10.1016/j.cmet.2014.09.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/10/2014] [Accepted: 09/08/2014] [Indexed: 12/12/2022]
Abstract
Cholesterol metabolism is closely interrelated with cardiovascular disease in humans. Dietary supplementation with omega-6 polyunsaturated fatty acids including arachidonic acid (AA) was shown to favorably affect plasma LDL-C and HDL-C. However, the underlying mechanisms are poorly understood. By combining data from a GWAS screening in >100,000 individuals of European ancestry, mediator lipidomics, and functional validation studies in mice, we identify the AA metabolome as an important regulator of cholesterol homeostasis. Pharmacological modulation of AA metabolism by aspirin induced hepatic generation of leukotrienes (LTs) and lipoxins (LXs), thereby increasing hepatic expression of the bile salt export pump Abcb11. Induction of Abcb11 translated in enhanced reverse cholesterol transport, one key function of HDL. Further characterization of the bioactive AA-derivatives identified LX mimetics to lower plasma LDL-C. Our results define the AA metabolomeasconserved regulator of cholesterol metabolism, and identify AA derivatives as promising therapeutics to treat cardiovascular disease in humans.
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Affiliation(s)
- Egon Demetz
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Andrea Schroll
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Kristina Auer
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Christiane Heim
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Josef R Patsch
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Philipp Eller
- Department of Internal Medicine, Angiology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Markus Theurl
- Department of Internal Medicine III, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Milan Theurl
- Department of Ophthalmology and Optometry, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Markus Seifert
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Daniela Lener
- Department of Internal Medicine III, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Ursula Stanzl
- Department of Internal Medicine III, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - David Haschka
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Malte Asshoff
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Stefanie Dichtl
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Manfred Nairz
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Eva Huber
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Martin Stadlinger
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Alexander R Moschen
- Department of Internal Medicine I, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Xiaorong Li
- Department of Pharmacology, Capital Medical University, Number 10 Xitoutiao, You An Men, 100069 Beijing, China
| | - Petra Pallweber
- Department of Pediatrics II, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria
| | - Hubert Scharnagl
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Winfried März
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria; Department of Internal Medicine, Medical Clinic V, Mannheim Medical Faculty, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; Synlab Academy, Harrlachweg 1, 68163 Mannheim, Germany
| | - Marcus E Kleber
- Department of Internal Medicine, Medical Clinic V, Mannheim Medical Faculty, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Katia Garlaschelli
- Center for the Study of Atherosclerosis, Bassini Hospital, via Gorki 50, 20092 Cinisello Balsamo Milan, Italy
| | - Patrizia Uboldi
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi di Milano, via Balzaretti 9, 20133 Milan, Italy
| | - Alberico L Catapano
- Department of Pharmacological and Biomolecular Sciences, Università Degli Studi di Milano, via Balzaretti 9, 20133 Milan, Italy; IRCCS Multimedica, via Milanese 300, 20099 Sesto San Giovanni Milan, Italy
| | - Frans Stellaard
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Mats Rudling
- Department of Medicine and Department of Biosciences and Nutrition, Karolinska Institute at Karolinska University Hospital Huddinge, 14186 Stockholm, Sweden
| | - Keiji Kuba
- Department of Biological Informatics and Experimental Therapeutics, Graduate School of Medicine, Akita University, 1-1 Tegata Gakuen-machi, 010-8502 Akita City, Japan
| | - Yumiko Imai
- Department of Biological Informatics and Experimental Therapeutics, Graduate School of Medicine, Akita University, 1-1 Tegata Gakuen-machi, 010-8502 Akita City, Japan
| | - Makoto Arita
- Department of Health Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo, 113-8654 Tokyo, Japan
| | - John D Schuetz
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, MS313, Memphis, TN 38105, USA
| | - Peter P Pramstaller
- Center for Biomedicine, European Academy Bozen/Bolzano (EURAC), Drususallee 1, 39100 Bolzano, Italy-Affiliated Institute of the University of Luebeck, Ratzeburger Allee 160, 23562 Luebeck, Germany
| | - Uwe J F Tietge
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Giuseppe D Norata
- Center for the Study of Atherosclerosis, Bassini Hospital, via Gorki 50, 20092 Cinisello Balsamo Milan, Italy; Department of Pharmacological and Biomolecular Sciences, Università Degli Studi di Milano, via Balzaretti 9, 20133 Milan, Italy; The Blizard Institute, Centre for Diabetes, Barts and The London School of Medicine & Dentistry, Queen Mary University, 4 Newark Street, E1 2AT London, UK
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Andrew A Hicks
- Center for Biomedicine, European Academy Bozen/Bolzano (EURAC), Drususallee 1, 39100 Bolzano, Italy-Affiliated Institute of the University of Luebeck, Ratzeburger Allee 160, 23562 Luebeck, Germany
| | - Guenter Weiss
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria.
| | - Ivan Tancevski
- Department of Internal Medicine VI, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria.
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Soroka CJ, Boyer JL. Biosynthesis and trafficking of the bile salt export pump, BSEP: therapeutic implications of BSEP mutations. Mol Aspects Med 2014; 37:3-14. [PMID: 23685087 PMCID: PMC3784619 DOI: 10.1016/j.mam.2013.05.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 04/25/2013] [Accepted: 05/07/2013] [Indexed: 12/17/2022]
Abstract
The bile salt export pump (BSEP, ABCB11) is the primary transporter of bile acids from the hepatocyte to the biliary system. This rate-limiting step in bile formation is essential to the formation of bile salt dependent bile flow, the enterohepatic circulation of bile acids, and the digestion of dietary fats. Mutations in BSEP are associated with cholestatic diseases such as progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2), drug-induced cholestasis, and intrahepatic cholestasis of pregnancy. Development of clinical therapies for these conditions necessitates a clear understanding of the cell biology of biosynthesis, trafficking, and transcriptional and translational regulation of BSEP. This chapter will focus on the molecular and cell biological aspects of this critical hepatic membrane transporter.
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Affiliation(s)
- Carol J Soroka
- Yale University School of Medicine, Department of Internal Medicine, New Haven, CT 06520, United States.
| | - James L Boyer
- Yale University School of Medicine, Department of Internal Medicine, New Haven, CT 06520, United States.
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31
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Baghdasaryan A, Chiba P, Trauner M. Clinical application of transcriptional activators of bile salt transporters. Mol Aspects Med 2014; 37:57-76. [PMID: 24333169 PMCID: PMC4045202 DOI: 10.1016/j.mam.2013.12.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/21/2013] [Accepted: 12/01/2013] [Indexed: 02/07/2023]
Abstract
Hepatobiliary bile salt (BS) transporters are critical determinants of BS homeostasis controlling intracellular concentrations of BSs and their enterohepatic circulation. Genetic or acquired dysfunction of specific transport systems causes intrahepatic and systemic retention of potentially cytotoxic BSs, which, in high concentrations, may disturb integrity of cell membranes and subcellular organelles resulting in cell death, inflammation and fibrosis. Transcriptional regulation of canalicular BS efflux through bile salt export pump (BSEP), basolateral elimination through organic solute transporters alpha and beta (OSTα/OSTβ) as well as inhibition of hepatocellular BS uptake through basolateral Na(+)-taurocholate cotransporting polypeptide (NTCP) represent critical steps in protection from hepatocellular BS overload and can be targeted therapeutically. In this article, we review the potential clinical implications of the major BS transporters BSEP, OSTα/OSTβ and NTCP in the pathogenesis of hereditary and acquired cholestatic syndromes, provide an overview on transcriptional control of these transporters by the key regulatory nuclear receptors and discuss the potential therapeutic role of novel transcriptional activators of BS transporters in cholestasis.
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Affiliation(s)
- Anna Baghdasaryan
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria; Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Medical University of Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria.
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32
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Kagawa T, Orii R, Hirose S, Arase Y, Shiraishi K, Mizutani A, Tsukamoto H, Mine T. Ursodeoxycholic acid stabilizes the bile salt export pump in the apical membrane in MDCK II cells. J Gastroenterol 2014; 49:890-9. [PMID: 23722250 DOI: 10.1007/s00535-013-0833-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 05/03/2013] [Indexed: 02/04/2023]
Abstract
BACKGROUND Ursodeoxycholic acid (UDCA) partly exerts choleretic effects by modifying the function of the bile salt export pump (Bsep, ABCB11). UDCA induces insertion of Bsep into the canalicular membrane of hepatocytes; however, underlying mechanisms remain unknown. We aimed to elucidate molecular mechanisms behind UDCA-induced Bsep activation. METHODS We established MDCK II cells stably expressing both Bsep and Na(+)-taurocholate cotransporting polypeptide, and investigated the effect of UDCA on activity and protein expression of Bsep using these cells. We performed inhibitor study to know the molecules involved in UDCA-induced Bsep activation, and also tested the influence of UDCA on Bsep having a disease-associated mutation. RESULTS UDCA activated Bsep in a dose-dependent manner. UDCA did not affect Bsep protein expression in whole cell lysates but increased its apical surface expression by extending the half-life from 2.4 to 5.0 h. This effect was specific to Bsep because UDCA did not affect other apical and basolateral proteins, and was independent of protein kinase A, adenylate cyclase, p38(MAPK), phosphatidylinositide 3-kinase, Ca(2+), and microtubules. NorUDCA activated Bsep similar to UDCA; however, cholic acid, taurocholic acid, and tauroUDCA had no effect. UDCA significantly increased the activity of Bsep with a benign recurrent intrahepatic cholestasis 2 mutation (A570T) but did not affect Bsep with a progressive familial intrahepatic cholestasis 2 mutation (G982R or D482G). CONCLUSIONS We demonstrated that UDCA stabilizes Bsep protein in the apical membrane and increases its activity in MDCK II cells, presumably by retarding the endocytotic process.
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Affiliation(s)
- Tatehiro Kagawa
- Division of Gastroenterology, Department of Internal Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa, 259-1193, Japan,
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Liu BB, Kong J, Wu SD, Wang Y. Bile acid salt export pump: Molecular mechanisms of transcription and intracellular regulation. Shijie Huaren Xiaohua Zazhi 2014; 22:788-794. [DOI: 10.11569/wcjd.v22.i6.788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bile salt export pump (BSEP), a member of ATP binding cassette (ABC), is responsible for transporting bile salt and is located on cholangiole lateral membrane. In humans, BSEP defects can lead to different types of cholestatic diseases, including hereditary or acquired liver diseases. In addition, BSEP is the most likely candidate gene for Lith1 stone. The bile salt plays an important role in many physiological and pathophysiological processes, and the scientific community has attached great importance to the research on the regulatory mechanism of the expression of BSEP. This paper summarizes the research related to transcriptional regulation of BSEP, and expression or functional changes of BSEP on cholangiole lateral membrane caused by intracellular transport changes, including intracellular endoplasmic reticulum and cell membrane ubiquitination-protease mediated protein degradation, short-term phosphorylation of BSEP, glycosylation, ubiquitination, and the regulatory effect of cholangiole lateral membrane-associated proteins.
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Abstract
Bile acids, synthesized from cholesterol, are known to produce beneficial as well as toxic effects in the liver. The beneficial effects include choleresis, immunomodulation, cell survival, while the toxic effects include cholestasis, apoptosis and cellular toxicity. It is believed that bile acids produce many of these effects by activating intracellular signaling pathways. However, it has been a challenge to relate intracellular signaling to specific and at times opposing effects of bile acids. It is becoming evident that bile acids produce different effects by activating different isoforms of phosphoinositide 3-kinase (PI3K), Protein kinase Cs (PKCs), and mitogen activated protein kinases (MAPK). Thus, the apoptotic effect of bile acids may be mediated via PI3K-110γ, while cytoprotection induce by cAMP-GEF pathway involves activation of PI3K-p110α/β isoforms. Atypical PKCζ may mediate beneficial effects and nPKCε may mediate toxic effects, while cPKCα and nPKCδ may be involved in both beneficial and toxic effects of bile acids. The opposing effects of nPKCδ activation may depend on nPKCδ phosphorylation site(s). Activation of ERK1/2 and JNK1/2 pathway appears to mediate beneficial and toxic effects, respectively, of bile acids. Activation of p38α MAPK and p38β MAPK may mediate choleretic and cholestatic effects, respectively, of bile acids. Future studies clarifying the isoform specific effects on bile formation should allow us to define potential therapeutic targets in the treatment of cholestatic disorders.
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Affiliation(s)
- Mohammed Sawkat Anwer
- Department of Biomedical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Road, North Grafton, MA, USA
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35
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Abstract
Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (∼1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions.
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Affiliation(s)
- James L Boyer
- Department of Medicine and Liver Center, Yale University School of Medicine, New Haven, Connecticut, USA.
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36
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Ellinger P, Kluth M, Stindt J, Smits SHJ, Schmitt L. Detergent screening and purification of the human liver ABC transporters BSEP (ABCB11) and MDR3 (ABCB4) expressed in the yeast Pichia pastoris. PLoS One 2013; 8:e60620. [PMID: 23593265 PMCID: PMC3617136 DOI: 10.1371/journal.pone.0060620] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 02/28/2013] [Indexed: 12/27/2022] Open
Abstract
The human liver ATP-binding cassette (ABC) transporters bile salt export pump (BSEP/ABCB11) and the multidrug resistance protein 3 (MDR3/ABCB4) fulfill the translocation of bile salts and phosphatidylcholine across the apical membrane of hepatocytes. In concert with ABCG5/G8, these two transporters are responsible for the formation of bile and mutations within these transporters can lead to severe hereditary diseases. In this study, we report the heterologous overexpression and purification of human BSEP and MDR3 as well as the expression of the corresponding C-terminal GFP-fusion proteins in the yeast Pichia pastoris. Confocal laser scanning microscopy revealed that BSEP-GFP and MDR3-GFP are localized in the plasma membrane of P. pastoris. Furthermore, we demonstrate the first purification of human BSEP and MDR3 yielding ∼1 mg and ∼6 mg per 100 g of wet cell weight, respectively. By screening over 100 detergents using a dot blot technique, we found that only zwitterionic, lipid-like detergents such as Fos-cholines or Cyclofos were able to extract both transporters in sufficient amounts for subsequent functional analysis. For MDR3, fluorescence-detection size exclusion chromatography (FSEC) screens revealed that increasing the acyl chain length of Fos-Cholines improved monodispersity. BSEP purified in n-dodecyl-β-D-maltoside or Cymal-5 after solubilization with Fos-choline 16 from P. pastoris membranes showed binding to ATP-agarose. Furthermore, detergent-solubilized and purified MDR3 showed a substrate-inducible ATPase activity upon addition of phosphatidylcholine lipids. These results form the basis for further biochemical analysis of human BSEP and MDR3 to elucidate the function of these clinically relevant ABC transporters.
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Affiliation(s)
- Philipp Ellinger
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
| | - Marianne Kluth
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
| | - Jan Stindt
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
| | - Sander H. J. Smits
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, Düsseldorf, Germany
- * E-mail:
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37
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Kordes C, Sawitza I, Götze S, Häussinger D. Stellate cells from rat pancreas are stem cells and can contribute to liver regeneration. PLoS One 2012; 7:e51878. [PMID: 23272184 PMCID: PMC3521726 DOI: 10.1371/journal.pone.0051878] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 11/13/2012] [Indexed: 12/13/2022] Open
Abstract
The identity of pancreatic stem/progenitor cells is still under discussion. They were suggested to derive from the pancreatic ductal epithelium and/or islets. Here we report that rat pancreatic stellate cells (PSC), which are thought to contribute to pancreatic fibrosis, have stem cell characteristics. PSC reside in islets and between acini and display a gene expression pattern similar to umbilical cord blood stem cells and mesenchymal stem cells. Cytokine treatment of isolated PSC induced the expression of typical hepatocyte markers. The PSC-derived hepatocyte-like cells expressed endodermal proteins such as bile salt export pump along with the mesodermal protein vimentin. The transplantation of culture-activated PSC from enhanced green fluorescent protein-expressing rats into wild type rats after partial hepatectomy in the presence of 2-acetylaminofluorene revealed that PSC were able to reconstitute large areas of the host liver through differentiation into hepatocytes and cholangiocytes. This developmental fate of transplanted PSC was confirmed by fluorescence in situ hybridization of chromosome Y after gender-mismatched transplantation of male PSC into female rats. Transplanted PSC displayed long-lasting survival, whereas muscle fibroblasts were unable to integrate into the host liver. The differentiation potential of PSC was further verified by the transplantation of clonally expanded PSC. PSC clones maintained the expression of stellate cell and stem cell markers and preserved their differentiation potential, which indicated self-renewal potential of PSC. These findings demonstrate that PSC have stem cell characteristics and can contribute to the regeneration of injured organs through differentiation across tissue boundaries.
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Affiliation(s)
- Claus Kordes
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Iris Sawitza
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Silke Götze
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Dieter Häussinger
- Clinic of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail:
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38
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The bile salt export pump (BSEP) in health and disease. Clin Res Hepatol Gastroenterol 2012; 36:536-53. [PMID: 22795478 DOI: 10.1016/j.clinre.2012.06.006] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 05/29/2012] [Accepted: 06/06/2012] [Indexed: 02/04/2023]
Abstract
The bile salt export pump (BSEP) is the major transporter for the secretion of bile acids from hepatocytes into bile in humans. Mutations of BSEP are associated with cholestatic liver diseases of varying severity including progressive familial intrahepatic cholestasis type 2 (PFIC-2), benign recurrent intrahepatic cholestasis type 2 (BRIC-2) and genetic polymorphisms are linked to intrahepatic cholestasis of pregnancy (ICP) and drug-induced liver injury (DILI). Detailed analysis of these diseases has considerably increased our knowledge about physiology and pathophysiology of bile secretion in humans. This review focuses on expression, localization, and function, short- and long-term regulation of BSEP as well as diseases association and treatment options for BSEP-associated diseases.
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Malinen MM, Palokangas H, Yliperttula M, Urtti A. Peptide Nanofiber Hydrogel Induces Formation of Bile Canaliculi Structures in Three-Dimensional Hepatic Cell Culture. Tissue Eng Part A 2012; 18:2418-25. [DOI: 10.1089/ten.tea.2012.0046] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- Melina M. Malinen
- Centre for Drug Research, University of Helsinki, Helsinki, Finland
- Division of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Harri Palokangas
- Centre for Drug Research, University of Helsinki, Helsinki, Finland
| | - Marjo Yliperttula
- Division of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Arto Urtti
- Centre for Drug Research, University of Helsinki, Helsinki, Finland
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Boaglio AC, Zucchetti AE, Toledo FD, Barosso IR, Sánchez Pozzi EJ, Crocenzi FA, Roma MG. ERK1/2 and p38 MAPKs are complementarily involved in estradiol 17ß-D-glucuronide-induced cholestasis: crosstalk with cPKC and PI3K. PLoS One 2012; 7:e49255. [PMID: 23166621 PMCID: PMC3498151 DOI: 10.1371/journal.pone.0049255] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 10/04/2012] [Indexed: 12/17/2022] Open
Abstract
Objective The endogenous, cholestatic metabolite estradiol 17ß-d-glucuronide (E217G) induces endocytic internalization of the canalicular transporters relevant to bile formation, Bsep and Mrp2. We evaluated here whether MAPKs are involved in this effect. Design ERK1/2, JNK1/2, and p38 MAPK activation was assessed by the increase in their phosphorylation status. Hepatocanalicular function was evaluated in isolated rat hepatocyte couplets (IRHCs) by quantifying the apical secretion of fluorescent Bsep and Mrp2 substrates, and in isolated, perfused rat livers (IPRLs), using taurocholate and 2,4-dinitrophenyl-S-glutathione, respectively. Protein kinase participation in E217G-induced secretory failure was assessed by co-administering selective inhibitors. Internalization of Bsep/Mrp2 was assessed by confocal microscopy and image analysis. Results E217G activated all kinds of MAPKs. The PI3K inhibitor wortmannin prevented ERK1/2 activation, whereas the cPKC inhibitor Gö6976 prevented p38 activation, suggesting that ERK1/2 and p38 are downstream of PI3K and cPKC, respectively. The p38 inhibitor SB203580 and the ERK1/2 inhibitor PD98059, but not the JNK1/2 inhibitor SP600125, partially prevented E217G-induced changes in transporter activity and localization in IRHCs. p38 and ERK1/2 co-inhibition resulted in additive protection, suggesting complementary involvement of these MAPKs. In IPRLs, E217G induced endocytosis of canalicular transporters and a rapid and sustained decrease in bile flow and biliary excretion of Bsep/Mrp2 substrates. p38 inhibition prevented this initial decay, and the internalization of Bsep/Mrp2. Contrarily, ERK1/2 inhibition accelerated the recovery of biliary secretion and the canalicular reinsertion of Bsep/Mrp2. Conclusions cPKC/p38 MAPK and PI3K/ERK1/2 signalling pathways participate complementarily in E217G-induced cholestasis, through internalization and sustained intracellular retention of canalicular transporters, respectively.
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Affiliation(s)
| | | | | | | | | | - Fernando A. Crocenzi
- Institute of Experimental Physiology, National Scientific and Technical Research Council/National University of Rosario, Rosario, Argentina
- * E-mail: (FAC); (MGR)
| | - Marcelo G. Roma
- Institute of Experimental Physiology, National Scientific and Technical Research Council/National University of Rosario, Rosario, Argentina
- * E-mail: (FAC); (MGR)
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Ursodeoxycholic acid in cholestasis: linking action mechanisms to therapeutic applications. Clin Sci (Lond) 2011; 121:523-44. [PMID: 21854363 DOI: 10.1042/cs20110184] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UDCA (ursodeoxycholic acid) is the therapeutic agent most widely used for the treatment of cholestatic hepatopathies. Its use has expanded to other kinds of hepatic diseases, and even to extrahepatic ones. Such versatility is the result of its multiple mechanisms of action. UDCA stabilizes plasma membranes against cytolysis by tensioactive bile acids accumulated in cholestasis. UDCA also halts apoptosis by preventing the formation of mitochondrial pores, membrane recruitment of death receptors and endoplasmic-reticulum stress. In addition, UDCA induces changes in the expression of metabolizing enzymes and transporters that reduce bile acid cytotoxicity and improve renal excretion. Its capability to positively modulate ductular bile flow helps to preserve the integrity of bile ducts. UDCA also prevents the endocytic internalization of canalicular transporters, a common feature in cholestasis. Finally, UDCA has immunomodulatory properties that limit the exacerbated immunological response occurring in autoimmune cholestatic diseases by counteracting the overexpression of MHC antigens and perhaps by limiting the production of cytokines by immunocompetent cells. Owing to this multi-functionality, it is difficult to envisage a substitute for UDCA that combines as many hepatoprotective effects with such efficacy. We predict a long-lasting use of UDCA as the therapeutic agent of choice in cholestasis.
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Saeki J, Sekine S, Horie T. LPS-induced dissociation of multidrug resistance-associated protein 2 (Mrp2) and radixin is associated with Mrp2 selective internalization in rats. Biochem Pharmacol 2011; 81:178-84. [DOI: 10.1016/j.bcp.2010.09.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 09/16/2010] [Accepted: 09/16/2010] [Indexed: 01/17/2023]
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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: 200] [Impact Index Per Article: 15.4] [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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Swift B, Pfeifer ND, Brouwer KLR. Sandwich-cultured hepatocytes: an in vitro model to evaluate hepatobiliary transporter-based drug interactions and hepatotoxicity. Drug Metab Rev 2010; 42:446-71. [PMID: 20109035 PMCID: PMC3097390 DOI: 10.3109/03602530903491881] [Citation(s) in RCA: 290] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sandwich-cultured hepatocytes (SCH) are a powerful in vitro tool that can be utilized to study hepatobiliary drug transport, species differences in drug transport, transport protein regulation, drug-drug interactions, and hepatotoxicity. This review provides an up-to-date summary of the SCH model, including a brief history of, and introduction to, the use of SCH, as well as methodology to evaluate hepatobiliary drug disposition. A summary of the literature that has utilized this model to examine the interplay between drug-metabolizing enzymes and transport proteins, drug-drug interactions at the transport level, and hepatotoxicity as a result of altered hepatic transport also is provided.
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Affiliation(s)
- Brandon Swift
- University of North Carolina at Chapel Hill, 27599-7569, USA
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Stross C, Helmer A, Weissenberger K, Görg B, Keitel V, Häussinger D, Kubitz R. Protein kinase C induces endocytosis of the sodium taurocholate cotransporting polypeptide. Am J Physiol Gastrointest Liver Physiol 2010; 299:G320-8. [PMID: 20539008 DOI: 10.1152/ajpgi.00180.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bile salts influence signaling and metabolic pathways. In hepatocytes, the sodium taurocholate cotransporting polypeptide (Ntcp) is a major determinant of intracellular bile salt levels. Short-term downregulation of Ntcp is not well characterized to date. FLAG and enhanced green fluorescent protein (EGFP) tags were cloned to the extra- and intracellular termini of Ntcp. Endocytosis of Ntcp in transfected HepG2 cells was visualized by fluorescence of EGFP, and membrane surface expression of Ntcp was quantified by flow cytometry with fluorochrome-labeled FLAG antibodies. Activation of protein kinase C (PKC) by phorbolester or thymeleatoxin an activator of Ca(2+)-dependent conventional PKCs (cPKCs), induced endocytosis of Ntcp, whereas the Na(+)-K(+)-ATPase remained in the plasma membrane. The PKC inhibitor BIM I and the cPKC-selective inhibitor Gö6976 abolished PMA-induced endocytosis. Because of this internalization, cell surface expression of Ntcp was reduced by 36 +/- 7%, bile salt uptake was decreased by 25%, and taurolithocholate sulfate-induced cell toxicity was prevented. In conclusion, Ca(2+)-dependent PKCs induce vesicular retrieval of Ntcp, thereby reducing bile salt uptake. This mechanism may protect hepatocytes from toxic intracellular bile salt concentrations.
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Affiliation(s)
- Claudia Stross
- Dept. of Gastroenterology, Hepatology and Infectiology, Heinrich-Heine Univ. of Düsseldorf, Germany
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Lam P, Soroka CJ, Boyer JL. The bile salt export pump: clinical and experimental aspects of genetic and acquired cholestatic liver disease. Semin Liver Dis 2010; 30:125-33. [PMID: 20422495 PMCID: PMC3008346 DOI: 10.1055/s-0030-1253222] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The primary transporter responsible for bile salt secretion is the bile salt export pump (BSEP, ABCB11), a member of the ATP-binding cassette (ABC) superfamily, which is located at the bile canalicular apical domain of hepatocytes. In humans, BSEP deficiency results in several different genetic forms of cholestasis, which include progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2), as well as other acquired forms of cholestasis such as drug-induced cholestasis (DIC) and intrahepatic cholestasis of pregnancy (ICP). Because bile salts play a pivotal role in a wide range of physiologic and pathophysiologic processes, regulation of BSEP expression has been a subject of intense research. The authors briefly describe the molecular characteristics of BSEP and then summarize what is known about its role in the pathogenesis of genetic and acquired cholestatic disorders, emphasizing experimental observations from animal models and cell culture in vitro systems.
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Affiliation(s)
- Ping Lam
- Liver Center, Yale University School of Medicine, New Haven, Connecticut
| | - Carol J. Soroka
- Liver Center, Yale University School of Medicine, New Haven, Connecticut
| | - James L. Boyer
- Liver Center, Yale University School of Medicine, New Haven, Connecticut
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Schonhoff CM, Webster CRL, Anwer MS. Cyclic AMP stimulates Mrp2 translocation by activating p38{alpha} MAPK in hepatic cells. Am J Physiol Gastrointest Liver Physiol 2010; 298:G667-74. [PMID: 20203059 PMCID: PMC2867428 DOI: 10.1152/ajpgi.00506.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cyclic AMP (cAMP) induces translocation of multidrug resistant protein 2 (Mrp2) to the canalicular membrane and activates p38 MAPK in rat hepatocytes. In this study, we tested the hypothesis that cAMP-induced Mrp2 translocation may be mediated via p38 MAPK. Studies were conducted in rat hepatocytes and in a human hepatoma cell line, HuH-7. In rat hepatocytes, cAMP increased Mrp2 translocation and p38 MAPK activity. These effects of cAMP were inhibited by SB203580, an inhibitor of p38 MAPK. Wortmannin, a specific inhibitor of phosphoinositide-3-kinase (PI3K), did not inhibit cAMP induced activation of p38 MAPK, indicating PI3K-independent activation of p38 MAPK by cAMP. To further define the role of p38 MAPK, molecular approaches were used to up- or downregulate p38 MAPK activity in HuH-7 cells using constitutively active (CA) and dominant-negative (DN) MAPK kinase 3 and 6 (MKK3/6). MKK3/6 are upstream kinases responsible for the activation of p38 MAPK. Cells transfected with CAMKK6 showed increased p38 MAPK activity and MRP2 translocation compared with empty vector. cAMP-induced activation of p38 MAPK was inhibited in cells transfected with DNMKK3/6 and DNMKK3, but not with DNMKK6. DNMKK3/6 and DNMKK3 also inhibited cAMP-induced MRP2 translocation. cAMP selectively activated p38alpha MAPK in HuH-7 cells. Knockdown of p38alpha MAPK by short heterodimer RNA resulted in decreased level of p38 MAPK and failure of cAMP to stimulate MRP2 translocation. Taken together, these results suggest that cAMP-induced MRP2 translocation in hepatic cells is mediated via PI3K-independent and MKK3-mediated activation of p38alpha MAPK.
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Affiliation(s)
| | - Cynthia R. L. Webster
- 2Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts
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Hohenester S, Oude-Elferink RPJ, Beuers U. Primary biliary cirrhosis. Semin Immunopathol 2009; 31:283-307. [PMID: 19603170 PMCID: PMC2758170 DOI: 10.1007/s00281-009-0164-5] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Accepted: 05/22/2009] [Indexed: 12/13/2022]
Abstract
Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9–10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC.
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Affiliation(s)
- Simon Hohenester
- Department of Gastroenterology & Hepatology/Liver Center, Academic Medical Center, G4-213, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
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Abstract
Several studies have characterized the cellular and molecular mechanisms of hepatocyte injury caused by the retention of hydrophobic bile acids (BAs) in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial injury in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced injury in hepatocytes. The major beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyl-N-methylglycine or cholylsarcosine, have also aroused pharmacological interest owing to their protective properties.
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Antiepileptic drugs reduce efficacy of methotrexate chemotherapy by downregulation of Reduced folate carrier transport activity. Leukemia 2009; 23:1087-97. [DOI: 10.1038/leu.2009.6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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