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Delaunay JL, Durand-Schneider AM, Dossier C, Falguières T, Gautherot J, Davit-Spraul A, Aït-Slimane T, Housset C, Jacquemin E, Maurice M. A functional classification of ABCB4 variations causing progressive familial intrahepatic cholestasis type 3. Hepatology 2016; 63:1620-31. [PMID: 26474921 DOI: 10.1002/hep.28300] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/24/2015] [Accepted: 10/15/2015] [Indexed: 12/12/2022]
Abstract
UNLABELLED Progressive familial intrahepatic cholestasis type 3 is caused by biallelic variations of ABCB4, most often (≥70%) missense. In this study, we examined the effects of 12 missense variations identified in progressive familial intrahepatic cholestasis type 3 patients. We classified these variations on the basis of the defects thus identified and explored potential rescue of trafficking-defective mutants by pharmacological means. Variations were reproduced in the ABCB4 complementary DNA and the mutants, thus obtained, expressed in HepG2 and HEK293 cells. Three mutants were either fully (I541F and L556R) or largely (Q855L) retained in the endoplasmic reticulum, in an immature form. Rescue of the defect, i.e., increase in the mature form at the bile canaliculi, was obtained by cell treatments with cyclosporin A or C and, to a lesser extent, B, D, or H. Five mutations with little or no effect on ABCB4 expression at the bile canaliculi caused a decrease (F357L, T775M, and G954S) or almost absence (S346I and P726L) of phosphatidylcholine secretion. Two mutants (T424A and N510S) were normally processed and expressed at the bile canaliculi, but their stability was reduced. We found no defect of the T175A mutant or of R652G, previously described as a polymorphism. In patients, the most severe phenotypes appreciated by the duration of transplant-free survival were caused by ABCB4 variants that were markedly retained in the endoplasmic reticulum and expressed in a homozygous status. CONCLUSION ABCB4 variations can be classified as follows: nonsense variations (I) and, on the basis of current findings, missense variations that primarily affect the maturation (II), activity (III), or stability (IV) of the protein or have no detectable effect (V); this classification provides a strong basis for the development of genotype-based therapies.
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Affiliation(s)
- Jean-Louis Delaunay
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
| | - Anne-Marie Durand-Schneider
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
| | - Claire Dossier
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
| | - Thomas Falguières
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
| | - Julien Gautherot
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
| | - Anne Davit-Spraul
- Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, Laboratoire de biochimie, Le Kremlin Bicêtre, France
| | - Tounsia Aït-Slimane
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
| | - Chantal Housset
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France.,Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine, Centre de Référence Maladies Rares Maladies Inflammatoires des Voies Biliaires & Service d'Hépatologie, Paris, France
| | - Emmanuel Jacquemin
- Assistance Publique-Hôpitaux de Paris, Hôpital Bicêtre, Hépatologie Pédiatrique & Unité de Transplantation Hépatique, Centre de Référence Maladies Rares Atrésies des Voies Biliaires de l'Enfant, Le Kremlin Bicêtre, France.,Université Paris-Sud 11, INSERM, UMR_S 1174, Hepatinov, Orsay, France
| | - Michèle Maurice
- Sorbonne Universités, UPMC Université Paris 06, INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, Paris, France
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Abstract
Cholestatic liver diseases encompass a wide spectrum of disorders with different causes, resulting in impaired bile flow and accumulation of bile acids and other potentially hepatotoxic cholephils. The understanding of the molecular mechanisms of bile formation and cholestasis has recently improved significantly through new insights into nuclear receptor (patho)biology. Nuclear receptors are ligand-activated transcription factors, which act as central players in the regulation of genes responsible for elimination and detoxification of biliary constituents accumulating in cholestasis. They also control other pathophysiologic processes such as inflammation, fibrogenesis, and carcinogenesis involved in the pathogenesis and disease progression of cholestasis liver diseases.
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Affiliation(s)
- Emina Halilbasic
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Anna Baghdasaryan
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
- Corresponding author. Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Vienna, Austria.
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Role of nuclear receptors for bile acid metabolism, bile secretion, cholestasis, and gallstone disease. Biochim Biophys Acta Mol Basis Dis 2011; 1812:867-78. [DOI: 10.1016/j.bbadis.2010.12.021] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/21/2010] [Accepted: 12/22/2010] [Indexed: 12/12/2022]
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Zollner G, Wagner M, Trauner M. Nuclear receptors as drug targets in cholestasis and drug-induced hepatotoxicity. Pharmacol Ther 2010; 126:228-43. [PMID: 20388526 DOI: 10.1016/j.pharmthera.2010.03.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 03/24/2010] [Indexed: 01/04/2023]
Abstract
Nuclear receptors are key regulators of various processes including reproduction, development, and metabolism of xeno- and endobiotics such as bile acids and drugs. Research in the last two decades provided researchers and clinicians with a detailed understanding of the regulation of these processes and, most importantly, also prompted the development of novel drugs specifically targeting nuclear receptors for the treatment of a variety of diseases. Some nuclear receptor agonists are already used in daily clinical practice but many more are currently designed or tested for the treatment of diabetes, dyslipidemia, fatty liver disease, cancer, drug hepatotoxicity and cholestasis. The hydrophilic bile acid ursodeoxycholic acid is currently the only available drug to treat cholestasis but its efficacy is limited. Therefore, development of novel treatments represents a major goal for both pharmaceutical industry and academic researchers. Targeting nuclear receptors in cholestasis is an intriguing approach since these receptors are critically involved in regulation of bile acid homeostasis. This review will discuss the general role of nuclear receptors in regulation of transporters and other enzymes maintaining bile acid homeostasis and will review the role of individual receptors as therapeutic targets. In addition, the central role of nuclear receptors and other transcription factors such as the aryl hydrocarbon receptor (AhR) and the nuclear factor-E2-related factor (Nrf2) in mediating drug disposition and their potential therapeutic role in drug-induced liver disease will be covered.
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Affiliation(s)
- Gernot Zollner
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, A-8036 Graz, Austria
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Zollner G, Trauner M. Nuclear receptors as therapeutic targets in cholestatic liver diseases. Br J Pharmacol 2009; 156:7-27. [PMID: 19133988 DOI: 10.1111/j.1476-5381.2008.00030.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cholestasis results in intrahepatic accumulation of cytotoxic bile acids, which cause liver damage ultimately leading to biliary fibrosis and cirrhosis. Cholestatic liver injury is counteracted by a variety of adaptive hepatoprotective mechanisms including alterations in bile acid transport, synthesis and detoxification. The underlying molecular mechanisms are mediated mainly at a transcriptional level via a complex network involving nuclear receptors including the farnesoid X receptor, pregnane X receptor, vitamin D receptor and constitutive androstane receptor, which target overlapping, although not identical, sets of genes. Because the intrinsic adaptive response to bile acids cannot fully prevent liver injury in cholestasis, therapeutic targeting of these receptors via specific and potent agonists may further enhance the hepatic defence against toxic bile acids. Activation of these receptors results in repression of bile acid synthesis, induction of phases I and II bile acid hydroxylation and conjugation and stimulation of alternative bile acid export while limiting hepatocellular bile acid import. Furthermore, the use of nuclear receptor ligands may not only influence bile acid transport and metabolism but may also directly target hepatic fibrogenesis and inflammation. Many drugs already used to treat cholestasis and its complications such as pruritus (e.g. ursodeoxycholic acid, rifampicin, fibrates) may act via activation of nuclear receptors. More specific and potent nuclear receptor ligands are currently being developed. This article will review the current knowledge on nuclear receptors and their potential role in the treatment of cholestatic liver diseases.
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Affiliation(s)
- Gernot Zollner
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
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Obeid R, Herrmann W. Homocysteine and lipids: S-adenosyl methionine as a key intermediate. FEBS Lett 2009; 583:1215-25. [PMID: 19324042 DOI: 10.1016/j.febslet.2009.03.038] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 02/20/2009] [Accepted: 03/02/2009] [Indexed: 12/23/2022]
Abstract
An association between hyperlipidemia and hyperhomocysteinemia (HHCY) has been suggested. This link is clinically important in management of vascular risk factors especially in elderly people and patients with metabolic syndrome. Higher plasma homocysteine (Hcy) was associated with lower high-density lipoprotein (HDL)-cholesterol level. Moreover, HHCY was associated with disturbed plasma lipids or fatty liver. It seems that hypomethylation associated with HHCY is responsible for lipid accumulation in tissues. Decreased methyl group will decrease the synthesis of phosphatidylcholine, a major phospholipid required for very low-density lipoprotein (VLDL) assembly and homeostasis. The effect of Hcy on HDL-cholesterol is probably related to inhibiting enzymes or molecules participating in HDL-particle assembly.
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Affiliation(s)
- Rima Obeid
- Department of Clinical Chemistry and Laboratory Medicine, Central Laboratory, University Hospital, Saarland University, D-66424 Homburg/Saar, Germany
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Vanpouille C, Le Jeune N, Kryza D, Clotagatide A, Janier M, Dubois F, Perek N. Influence of multidrug resistance on (18)F-FCH cellular uptake in a glioblastoma model. Eur J Nucl Med Mol Imaging 2009; 36:1256-64. [PMID: 19300998 DOI: 10.1007/s00259-009-1101-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 02/16/2009] [Indexed: 10/21/2022]
Abstract
PURPOSE Multidrug resistance, aggressiveness and accelerated choline metabolism are hallmarks of malignancy and have motivated the development of new PET tracers like (18)F-FCH, an analogue of choline. Our aim was to study the relationship of multidrug resistance of cultured glioma cell lines and (18)F-FCH tracer uptake. METHODS We used an in vitro multidrug-resistant (MDR) glioma model composed of sensitive parental U87MG and derived resistant cells U87MG-CIS and U87MG-DOX. Aggressiveness, choline metabolism and transport were studied, particularly the expression of choline kinase (CK) and high-affinity choline transporter (CHT1). FCH transport studies were assessed in our glioblastoma model. RESULTS As expected, the resistant cell lines express P-glycoprotein (Pgp), multidrug resistance-associated protein isoform 1 (MRP1) and elevated glutathione (GSH) content and are also more mobile and more invasive than the sensitive U87MG cells. Our results show an overexpression of CK and CHT1 in the resistant cell lines compared to the sensitive cell lines. We found an increased uptake of FCH (in % of uptake per 200,000 cells) in the resistant cells compared to the sensitive ones (U87MG: 0.89 +/- 0.14; U87MG-CIS: 1.27 +/- 0.18; U87MG-DOX: 1.33 +/- 0.13) in line with accelerated choline metabolism and aggressive phenotype. CONCLUSIONS FCH uptake is not influenced by the two ATP-dependant efflux pumps: Pgp and MRP1. FCH would be an interesting probe for glioma imaging which would not be effluxed from the resistant cells by the classic MDR ABC transporters. Our results clearly show that FCH uptake reflects accelerated choline metabolism and is related to tumour aggressiveness and drug resistance.
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Affiliation(s)
- Claire Vanpouille
- Université de Lyon, Université Jean Monnet-Cancer Research Group IFRESIS 143, 42023, Saint-Etienne, France
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Chen G, Wang S, Bie P, Li X, Dong J. Endogenous bile salts are associated with bile duct injury in the rat liver transplantation model. Transplantation 2009; 87:330-9. [PMID: 19202437 DOI: 10.1097/tp.0b013e3181954fee] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Nonanastomotic biliary strictures are a serious complication after orthotopic liver transplantation (OLT) and are difficult to cure. We examined the role of endogenous bile salt toxicity in the pathogenesis of bile duct injury after OLT. MATERIALS AND METHODS A total of 90 Sprague-Dawley rats were divided into three groups: Sham-operated group (Sham, n=30), OLT group with 1 hr donor liver preservation (OLT-1h, n=30), and OLT group with 12 hr donor liver preservation (OLT-12h, n=30). Bile was collected and analyzed biochemically. The histopathologic study was performed to determine the intrahepatic bile duct morphologic changes. Hepatic expressions of bile transporters Ntcp, Bsep, Mdr2, and Oatps were detected. RESULTS During the first 2 weeks after transplantation, bile salt secretion was not parallel with phospholipid secretion, resulting in high biliary bile salt-to-phospholipid (BS:PL) ratio. The expression of bile transporters was consistent with the change of bile composition. Bile duct injury correlated significantly with bile salt secretion and BS:PL ratio. Moreover, OLT group with longer donor liver preservation time (OLT-12h) had significantly lower Mdr2 messenger RNA/protein level, higher BS:PL ratio, and better correlation between BS:PL ratio and bile duct injury compared with those of OLT-1h. CONCLUSIONS The unparallel secretion of bile salts and phospholipids results in cytotoxic bile formation with high BS:PL ratio after liver transplantation. Longer donor liver preservation time will increase graft bile cytotoxicity. The results of this study suggest that endogenous bile salts play a role in the pathogenesis of bile duct injury after OLT.
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Affiliation(s)
- Geng Chen
- Institute of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University, Chongqing, China
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Stahl S, Davies MR, Cook DI, Graham MJ. Nuclear hormone receptor-dependent regulation of hepatic transporters and their role in the adaptive response in cholestasis. Xenobiotica 2008; 38:725-77. [DOI: 10.1080/00498250802105593] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Marschall HU, Wagner M, Zollner G, Trauner M. Clinical Hepatotoxicity. Regulation and Treatment with Inducers of Transport and Cofactors. Mol Pharm 2007; 4:895-910. [DOI: 10.1021/mp060133c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Hanns-Ulrich Marschall
- Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden, and Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Martin Wagner
- Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden, and Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Gernot Zollner
- Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden, and Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Michael Trauner
- Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden, and Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
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Stojakovic T, Putz-Bankuti C, Fauler G, Scharnagl H, Wagner M, Stadlbauer V, Gurakuqi G, Stauber RE, März W, Trauner M. Atorvastatin in patients with primary biliary cirrhosis and incomplete biochemical response to ursodeoxycholic acid. Hepatology 2007; 46:776-84. [PMID: 17668874 DOI: 10.1002/hep.21741] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
UNLABELLED Statin therapy may target both hypercholesterolemia and cholestasis in primary biliary cirrhosis (PBC). However, little is known about the efficacy and safety of statins in PBC. The aim of this single-center study was therefore to prospectively examine the effects of atorvastatin on serum markers of cholestasis, aminotransferases, and lipid and bile acid metabolism as well as inflammatory and immunological markers in patients with PBC. Fifteen patients with early-stage PBC and an incomplete biochemical response to ursodeoxycholic acid (UDCA) therapy (defined as alkaline phosphatase 1.5-fold above the upper limit of normal after 1 year) were treated with atorvastatin 10 mg/day, 20 mg/day, and 40 mg/day for 4 weeks, respectively. Serum levels of alkaline phosphatase increased during atorvastatin 20 mg and 40 mg (P < 0.05), whereas leucine aminopeptidase and gamma-glutamyltransferase remained unchanged. No statistical differences in overall serum ALT, AST, bilirubin, and IgM levels were observed. However, atorvastatin was discontinued in 1 out of 15 patients because of ALT 2-fold above baseline, and 2 patients showed ALT elevations 3-fold above the upper limit of normal at the end of the atorvastatin treatment period. Serum total cholesterol and low-density lipoprotein cholesterol levels decreased by 35% and 49%, respectively (P < 0.001). Precursors of cholesterol biosynthesis (lanosterol, desmosterol, lathosterol) showed a similar pattern. No changes in serum bile acid levels and composition were observed during treatment. CONCLUSION Atorvastatin does not improve cholestasis in PBC patients with an incomplete biochemical response to UDCA but effectively reduces serum cholesterol levels.
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Affiliation(s)
- Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
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Dietzen DJ, Page KL, Tetzloff TA, Bohrer A, Turk J. Inhibition of 3-Hydroxy-3-Methylglutaryl Coenzyme A (HMG CoA) Reductase Blunts Factor VIIa/Tissue Factor and Prothrombinase Activities via Effects on Membrane Phosphatidylserine. Arterioscler Thromb Vasc Biol 2007; 27:690-6. [PMID: 17185615 DOI: 10.1161/01.atv.0000255949.51053.ce] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE 3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins) exhibit antithrombotic properties that are independent of reductions in circulating LDL cholesterol. We hypothesized that these antithrombotic properties are mediated by membrane alterations secondary to disrupted lipid metabolism. METHODS AND RESULTS EA.hy926 cells were incubated in the presence of 1 micromol/L atorvastatin supplemented with fetal bovine serum or lipid-depleted serum mixtures. Lipid restriction alone had no effect on cell lipid composition but when atorvastatin was included, phosphatidylserine, sphingomyelin, and cholesterol were reduced by 50% while ceramide content decreased by 70%. These changes in lipid composition did not alter the association of decay accelerating factor or tissue factor with lipid rafts. Atorvastatin in combination with lipid restriction reduced factor VIIa/tissue factor activity by as much as 75% but did not alter tissue factor expression. Prothrombinase activity was reduced to an extent similar to factor VIIa/tissue factor. Mevalonic acid but not LDL reversed the observed changes in lipid content and prothrombinase activity induced by atorvastatin. These findings were confirmed in primary cells. CONCLUSIONS Inhibition of HMG-CoA reductase limits exposure of phosphatidylserine at the cell surface by restricting the cellular pool of mevalonate-derived isoprenoids. This membrane alteration restricts the activity of proteolytic enzyme complexes that propagate the coagulation cascade.
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Affiliation(s)
- Dennis J Dietzen
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA.
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Zollner G, Marschall HU, Wagner M, Trauner M. Role of nuclear receptors in the adaptive response to bile acids and cholestasis: pathogenetic and therapeutic considerations. Mol Pharm 2006; 3:231-51. [PMID: 16749856 DOI: 10.1021/mp060010s] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cholestasis results in intrahepatic accumulation of cytotoxic bile acids which cause liver injury ultimately leading to biliary fibrosis and cirrhosis. Cholestatic liver damage is counteracted by a variety of intrinsic hepatoprotective mechanisms. Such defense mechanisms include repression of hepatic bile acid uptake and de novo bile acid synthesis. Furthermore, phase I and II bile acid detoxification is induced rendering bile acids more hydrophilic. In addition to "orthograde" export via canalicular export systems, these compounds are also excreted via basolateral "alternative" export systems into the systemic circulation followed by renal elimination. Passive glomerular filtration of hydrophilic bile acids, active renal tubular secretion, and repression of tubular bile acid reabsorption facilitate renal bile acid elimination during cholestasis. The underlying molecular mechanisms are mediated mainly at a transcriptional level via a complex network involving nuclear receptors and other transcription factors. So far, the farnesoid X receptor FXR, pregnane X receptor PXR, and vitamin D receptor VDR have been identified as nuclear receptors for bile acids. However, the intrinsic adaptive response to bile acids cannot fully prevent liver injury in cholestasis. Therefore, additional therapeutic strategies such as targeted activation of nuclear receptors are needed to enhance the hepatic defense against toxic bile acids.
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Affiliation(s)
- Gernot Zollner
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University Graz, Austria, and Karolinska University Hospital Huddinge, Stockholm, Sweden
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Geier A, Wagner M, Dietrich CG, Trauner M. Principles of hepatic organic anion transporter regulation during cholestasis, inflammation and liver regeneration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:283-308. [PMID: 17291602 DOI: 10.1016/j.bbamcr.2006.04.014] [Citation(s) in RCA: 221] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 04/21/2006] [Accepted: 04/24/2006] [Indexed: 12/16/2022]
Abstract
Hepatic uptake and biliary excretion of organic anions (e.g., bile acids and bilirubin) is mediated by hepatobiliary transport systems. Defects in transporter expression and function can cause or maintain cholestasis and jaundice. Recruitment of alternative export transporters in coordination with phase I and II detoxifying pathways provides alternative pathways to counteract accumulation of potentially toxic biliary constituents in cholestasis. The genes encoding for organic anion uptake (NTCP, OATPs), canalicular export (BSEP, MRP2) and alternative basolateral export (MRP3, MRP4) in liver are regulated by a complex interacting network of hepatocyte nuclear factors (HNF1, 3, 4) and nuclear (orphan) receptors (e.g., FXR, PXR, CAR, RAR, LRH-1, SHP, GR). Bile acids, proinflammatory cytokines, hormones and drugs mediate causative and adaptive transporter changes at a transcriptional level by interacting with these nuclear factors and receptors. Unraveling the underlying regulatory mechanisms may therefore not only allow a better understanding of the molecular pathophysiology of cholestatic liver diseases but should also identify potential pharmacological strategies targeting these regulatory networks. This review is focused on general principles of transcriptional basolateral and canalicular transporter regulation in inflammation-induced cholestasis, ethinylestradiol- and pregnancy-associated cholestasis, obstructive cholestasis and liver regeneration. Moreover, the potential therapeutic role of nuclear receptor agonists for the management of liver diseases is highlighted.
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Affiliation(s)
- Andreas Geier
- Department of Internal Medicine III, Aachen University (RWTH), Aachen, Germany.
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Trauner M, Wagner M, Fickert P, Zollner G. Molecular regulation of hepatobiliary transport systems: clinical implications for understanding and treating cholestasis. J Clin Gastroenterol 2005; 39:S111-24. [PMID: 15758646 DOI: 10.1097/01.mcg.0000155551.37266.26] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hepatobiliary transport systems are responsible for hepatic uptake and excretion of bile salts and other biliary constituents (eg, bilirubin) into bile. Hereditary transport defects can result in progressive familial and benign recurrent intrahepatic cholestasis. Exposure to acquired cholestatic injury (eg, drugs, hormones, proinflammatory cytokines, biliary obstruction or destruction) also results in altered expression and function of hepatic uptake and excretory systems, changes that may maintain and contribute to cholestasis and jaundice. Recruitment of alternative efflux pumps and induction of phase I and II detoxifying enzymes may limit hepatic accumulation of potentially toxic biliary constituents in cholestasis by providing alternative metabolic and escape routes. These molecular changes are mediated by bile salts, proinflammatory cytokines, drugs, and hormones at a transcriptional and posttranscriptional level. Alterations of hepatobiliary transporters and enzymes are not only relevant for a better understanding of the pathophysiology of cholestatic liver diseases, but may also represent important targets for pharmacotherapy. Drugs (eg, ursodeoxycholic acid, rifampicin) used to treat cholestatic liver diseases and pruritus may counteract cholestasis via stimulation of defective transporter expression and function. In addition, therapeutic strategies may be aimed at supporting and stimulating alternative detoxification pathways and elimination routes for bile salts in cholestasis.
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Affiliation(s)
- Michael Trauner
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University, Graz, Austria.
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Kamisako T, Ogawa H. Effects of pravastatin and bezafibrate on biliary lipid excretion and hepatic expression of Abcg5 and Abcg8 in the rat. J Gastroenterol Hepatol 2004; 19:879-83. [PMID: 15242490 DOI: 10.1111/j.1440-1746.2004.03377.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND AND AIM Multidrug resistance associated gene product 2 (Mdr2) is believed to have a significant role in biliary cholesterol and phospholipid secretions. Both pravastatin and bezafibrate resulted in Mdr2 induction, but increased cholesterol secretion was observed only in pravastatin treatment. To explore the mechanism, the hepatic expression of genes that are responsible for the metabolism of the lipids was studied. METHODS Rats were divided into three experimental groups: (i) the control group; (ii) the bezafibrate group, which was fed a diet containing 0.45% bezafibrate for 5 days; and (iii) the pravastatin group, which was fed a diet containing 0.1% pravastatin for 5 days. Serum, hepatic and biliary lipids were measured by colorimetric assays and hepatic mRNA related to lipid metabolism was studied by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS In the bezafibrate group biliary phospholipid secretion was increased although cholesterol secretion was not increased. In the pravastatin group, biliary cholesterol and phospholipid secretions were significantly increased. The biliary cholesterol/phospholipid ratio was decreased in the bezafibrate group, but the ratio did not change in the pravastatin group. Hepatic Mdr2, Abcg5 and Abcg8 mRNA expression was remarkably increased in the pravastatin group in comparison with the control group (184%, 264% and 247% of control value, respectively). In the bezafibrate group the hepatic gene expression of Mdr2 was increased (157% of control value), but there were no significant changes in hepatic Abcg5 and Abcg8 mRNA expression compared with the control group. CONCLUSIONS Compared with Mdr2, Abcg5 and Abcg8 seem to be more essential transporters for biliary secretion of cholesterol. Pravastatin upregulated Abcg5/Abcg8 while bezafibrate did not, which appears to explain the different effects of these compounds on biliary lipid secretion.
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Affiliation(s)
- Toshinori Kamisako
- Department of Hygiene, Kinki University School of Medicine, 377-2 Ohnohigashi, Osakasayama 589-8511, Japan.
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Kok T, Bloks VW, Wolters H, Havinga R, Jansen PLM, Staels B, Kuipers F. Peroxisome proliferator-activated receptor alpha (PPARalpha)-mediated regulation of multidrug resistance 2 (Mdr2) expression and function in mice. Biochem J 2003; 369:539-47. [PMID: 12381268 PMCID: PMC1223107 DOI: 10.1042/bj20020981] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2002] [Revised: 10/02/2002] [Accepted: 10/15/2002] [Indexed: 11/17/2022]
Abstract
Peroxisome proliferator-activated receptor alpha (PPARalpha) is a nuclear receptor that controls expression of genes involved in lipid metabolism and is activated by fatty acids and hypolipidaemic fibrates. Fibrates induce the hepatic expression of murine multidrug resistance 2 ( Mdr2 ), encoding the canalicular phospholipid translocator. The physiological role of PPARalpha in regulation of Mdr2 and other genes involved in bile formation is unknown. We found no differences in hepatic expression of the ATP binding cassette transporter genes Mdr2, Bsep (bile salt export pump), Mdr1a / 1b, Abca1 and Abcg5 / Abcg8 (implicated in cholesterol transport), the bile salt-uptake systems Ntcp (Na(+)-taurocholate co-transporting polypeptide gene) and Oatp1 (organic anion-transporting polypeptide 1 gene) or in bile formation between wild-type and Ppar alpha((-/-)) mice. Upon treatment of wild-type mice with ciprofibrate (0.05%, w/w, in diet for 2 weeks), the expression of Mdr2 (+3-fold), Mdr1a (+6-fold) and Mdr1b (+11-fold) mRNAs was clearly induced, while that of Oatp1 (-5-fold) was reduced. Mdr2 protein levels were increased, whereas Bsep, Ntcp and Oatp1 were drastically decreased. Exposure of cultured wild-type mouse hepatocytes to PPARalpha agonists specifically induced Mdr2 mRNA levels and did not affect expression of Mdr1a / 1b. Altered transporter expression in fibrate-treated wild-type mice was associated with a approximately 400% increase in bile flow: secretion of phospholipids and cholesterol was increased only during high-bile-salt infusions. No fibrate effects were observed in Ppar alpha((-/-)) mice. In conclusion, our results show that basal bile formation is not affected by PPARalpha deficiency in mice. The induction of Mdr2 mRNA and Mdr2 protein levels by fibrates is mediated by PPARalpha, while the induction of Mdr1a / 1b in vivo probably reflects a secondary phenomenon related to chronic PPARalpha activation.
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MESH Headings
- ATP Binding Cassette Transporter 1
- ATP Binding Cassette Transporter, Subfamily B/drug effects
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 11
- ATP Binding Cassette Transporter, Subfamily G, Member 5
- ATP Binding Cassette Transporter, Subfamily G, Member 8
- ATP-Binding Cassette Transporters/drug effects
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Bile/chemistry
- Bile/metabolism
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cells, Cultured
- Clofibric Acid/analogs & derivatives
- Clofibric Acid/pharmacology
- Fibric Acids
- Hepatocytes/physiology
- Lipid Metabolism
- Lipoproteins/genetics
- Lipoproteins/metabolism
- Liver/drug effects
- Liver/metabolism
- Liver/pathology
- Male
- Membrane Transport Proteins
- Mice
- Mice, Mutant Strains
- Organ Size/drug effects
- Organic Anion Transporters, Sodium-Dependent
- Organic Anion Transporters, Sodium-Independent/genetics
- Organic Anion Transporters, Sodium-Independent/metabolism
- Peroxisome Proliferators/pharmacology
- Pyrimidines/pharmacology
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Symporters
- Taurochenodeoxycholic Acid/administration & dosage
- Taurochenodeoxycholic Acid/pharmacology
- Transcription Factors/drug effects
- Transcription Factors/genetics
- Transcription Factors/metabolism
- ATP-Binding Cassette Sub-Family B Member 4
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Affiliation(s)
- Tineke Kok
- Groningen University Institute for Drug Exploration, Center for Liver, Digestive and Metabolic Diseases, Laboratory of Pediatrics, University Hospital Groningen, The Netherlands.
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19
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Kosters A, Jirsa M, Groen AK. Genetic background of cholesterol gallstone disease. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1637:1-19. [PMID: 12527402 DOI: 10.1016/s0925-4439(02)00173-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cholesterol gallstone formation is a multifactorial process involving a multitude of metabolic pathways. The primary pathogenic factor is hypersecretion of free cholesterol into bile. For people living in the Western Hemisphere, this is almost a normal condition, certainly in the elderly, which explains the very high incidence of gallstone disease. It is probably because the multifactorial background genes responsible for the high incidence have not yet been identified, despite the fact that genetic factors clearly play a role. Analysis of the many pathways involved in biliary cholesterol secretion reveals many potential candidates and considering the progress in unraveling the regulatory mechanisms of the responsible genes, identification of the primary gallstone genes will be successful in the near future.
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Affiliation(s)
- Astrid Kosters
- Department of Experimental Hepatology, AMC Liver Center S1-172, Academic Medical Center, Meibergdreef 69-71, 1105 BK, Amsterdam, The Netherlands.
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20
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Wakusawa S, Ikeda R, Shiono Y, Hayashi H. Protein kinase C-mediated down-regulation of MDR3 mRNA expression in Chang liver cells. Biochem Pharmacol 2001; 61:1339-45. [PMID: 11331069 DOI: 10.1016/s0006-2952(01)00601-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MDR3 is a phospholipid translocator homologous to MDR1 P-glycoprotein. MDR3 localizes to the canalicular membrane and contributes to the secretion of bile. To elucidate the role of protein kinase C in the regulation of MDR3 gene expression, we investigated the effect of phorbol 12-myristate 13-acetate (PMA) on the level of MDR3 mRNA in human Chang liver cells by a reverse transcription-polymerase chain reaction method. The steady-state expression of MDR3 mRNA was decreased by PMA after treatment for 8-20 hr and at concentrations of 1-100 nM. PMA also decreased the doxorubicin-induced expression of MDR3 mRNA. 4alpha-Phorbol 12,13-didecanoate, a negative control compound, did not decrease the expression at these concentrations. The down-regulatory effect of PMA was partially suppressed by the protein kinase C inhibitors 2-[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3-yl)maleimide (GF109203X) and calphostin C. Furthermore, cycloheximide, a protein synthesis inhibitor, antagonized the effect of PMA. From these results, it was suggested that the level of MDR3 mRNA was negatively regulated by a protein kinase C- and protein synthesis-dependent system and that the system regulated both the stable and inducible expression of MDR3 mRNA.
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Affiliation(s)
- S Wakusawa
- Department of Medicine, Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3, Kanagawa-machi, 920-1181, Kanazawa, Japan.
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21
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Hooiveld GJ, van Montfoort JE, Meijer DK, Müller M. Function and regulation of ATP-binding cassette transport proteins involved in hepatobiliary transport. Eur J Pharm Sci 2001; 12:525-43. [PMID: 11231121 DOI: 10.1016/s0928-0987(01)00101-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Hepatobiliary transport of endogenous and exogenous compounds is mediated by the coordinated action of multiple transport systems present at the sinusoidal (basolateral) and canalicular (apical) membrane domains of hepatocytes. During the last few years many of these transporters have been cloned and functionally characterized. In addition, the molecular bases of several forms of cholestatic liver disease have been defined. Combined, this has greatly expanded our understanding of the normal physiology of bile formation, the pathophysiology of intrahepatic cholestasis, as well as of drug elimination and disposition processes. In this review recent advances, with respect to function and regulation of ATP binding cassette transport proteins expressed in liver, are summarized and discussed.
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Affiliation(s)
- G J Hooiveld
- Groningen University Institute for Drug Exploration, Department of Pharmacokinetics and Drug Delivery, University of Groningen, Groningen, The Netherlands
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22
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Hooiveld GJ, van Montfoort JE, Meijer DK, Müller M. Function and regulation of ATP-binding cassette transport proteins involved in hepatobiliary transport. Eur J Pharm Sci 2000; 12:13-30. [PMID: 11121730 DOI: 10.1016/s0928-0987(00)00186-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Hepatobiliary transport of endogenous and exogenous compounds is mediated by the coordinated action of multiple transport systems present at the sinusoidal (basolateral) and canalicular (apical) membrane domains of hepatocytes. During the last few years many of these transporters have been cloned and functionally characterized. In addition, the molecular bases of several forms of cholestatic liver disease have been defined. Combined, this has greatly expanded our understanding of the normal physiology of bile formation, the pathophysiology of intrahepatic cholestasis, as well as of drug elimination and disposition processes. In this review recent advances, with respect to function and regulation of ATP binding cassette transport proteins expressed in liver, are summarized and discussed.
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Affiliation(s)
- G J Hooiveld
- Groningen University Institute for Drug Exploration, Department of Pharmacokinetics and Drug Delivery, University of Groningen, Groningen, The Netherlands
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23
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Gupta S, Todd Stravitz R, Pandak WM, Müller M, Reno Vlahcevic Z, Hylemon PB. Regulation of multidrug resistance 2 P-glycoprotein expression by bile salts in rats and in primary cultures of rat hepatocytes. Hepatology 2000; 32:341-7. [PMID: 10915741 DOI: 10.1053/jhep.2000.9605] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Biliary phospholipid secretion is tightly coupled to the secretion of free cholesterol and bile salts. The secretion of phospholipids across the canalicular membrane of hepatocytes occurs via the multidrug resistance 2 (mdr2) P-glycoprotein (Pgp). The mechanism underlying the coupling of bile salt and phospholipid secretion has not been elucidated. The aims of this study were to determine the effects of bile acid structure on the expression of mdr2 in vitro and in vivo. Under optimal culture conditions, taurine-conjugated bile acids (50 micromol/L) increased mdr2 messenger RNA (mRNA) levels in the following order: taurocholate (TCA) (288 +/- 36%, P <. 005) = taurodeoxycholate (TDCA) (276 +/- 36%, P <.025) > taurochenodeoxycholate (TCDCA) (216 +/- 34%, P <.025) > tauroursodeoxycholate (TUDCA) (175 +/- 28%, P <.05) of control levels. The increase in mdr2 mRNA levels by TCA was both time and concentration dependent. Cholate feeding to rats with intact enterohepatic circulation increased mdr2 transcriptional activity by 4-fold and protein mass by 1.9-fold. Chronic biliary diversion (CBD) decreased mdr2 mRNA levels to 66 +/- 9% (P <.025) of sham-operated controls. Intraduodenal infusion of TCA for 48 hours in CBD rats caused a significant increase in mdr2 mRNA levels (224%) as compared with CBD controls. A diet high in cholesterol (4%) decreased mdr2 mRNA levels to 57% +/- 2 (P <.001) of pair-fed controls. Squalestatin (1 micromol/L), an inhibitor of cholesterol biosynthesis, increased mdr2 mRNA levels by 8.8-fold (P <.005) in hepatocyte cultures after 24 hours. In conclusion, in the rat, bile acids up-regulated mdr2 transcriptional activity whereas cholesterol decreased mdr2 mRNA both in vitro and in vivo.
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Affiliation(s)
- S Gupta
- Department of Medicine-Gastroenterology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia, USA
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24
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Trauner M, Boyer JL. Cholestatic syndromes. Curr Opin Gastroenterol 2000; 16:239-50. [PMID: 17023881 DOI: 10.1097/00001574-200005000-00006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Continued advances in the field of liver cell biology and molecular biology have provided further insights into the normal physiology of bile secretion and the pathogenesis and therapy for cholestatic syndromes. Important new data have also been published about pathogenesis, clinical features, and treatment of primary biliary cirrhosis, primary sclerosing cholangitis, drug-induced cholestasis, and cholestatic syndromes caused by viral infections.
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Affiliation(s)
- M Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Karl Franzens University School of Medicine, Graz, Austria
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