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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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2
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Chen H, Wu D, Jiang W, Lei T, Lu C, Zhou T. Case Report: A Novel Homozygous Variant Identified in a Chinese Patient With Benign Recurrent Intrahepatic Cholestasis-Type 1. Front Med (Lausanne) 2021; 8:705489. [PMID: 34485338 PMCID: PMC8416249 DOI: 10.3389/fmed.2021.705489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/27/2021] [Indexed: 02/05/2023] Open
Abstract
Benign recurrent intrahepatic cholestasis (BRIC) is a rare hereditary cholestatic liver disorder. Accurate diagnosis and timely interventions are important in determining outcomes. Besides clinical and pathologic diagnosis, genetic study of BRIC remains limited. Here, we report a young man enduring recurrent jaundice and severe pruritus for 15 years. The increased level of direct bilirubin was the main biochemical abnormality, and the work-up for common causes of jaundice were unremarkable. Liver biopsy showed extensive cholestasis of hepatocytes in zone 3. The novel homozygous variant including c.1817T > C and p.I606T was detected on his ATP8B1gene. The patient was finally diagnosed with BRIC-1. His symptoms were relieved, and liver function tests returned to normal after taking ursodeoxycholic acid. This case provides a different perspective to the methodology employed when dealing with cases of jaundice and helping diagnose rare diseases.
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Affiliation(s)
- Huayu Chen
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Dongbo Wu
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Wei Jiang
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Ting Lei
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Changli Lu
- Department of Pathology, West China Hospital, Sichuan University, Chengdu, China
| | - Taoyou Zhou
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
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3
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Advanced Microscopy for Liver and Gut Ultrastructural Pathology in Patients with MVID and PFIC Caused by MYO5B Mutations. J Clin Med 2021; 10:jcm10091901. [PMID: 33924896 PMCID: PMC8125609 DOI: 10.3390/jcm10091901] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 02/07/2023] Open
Abstract
Mutations in the actin motor protein myosinVb (myo5b) cause aberrant apical cargo transport and the congenital enteropathy microvillus inclusion disease (MVID). Recently, missense mutations in myo5b were also associated with progressive familial intrahepatic cholestasis (MYO5B-PFIC). Here, we thoroughly characterized the ultrastructural and immuno-cytochemical phenotype of hepatocytes and duodenal enterocytes from a unique case of an adult MYO5B-PFIC patient who showed constant hepatopathy but only periodic enteric symptoms. Selected data from two other patients supported the findings. Advanced methods such as cryo-fixation, freeze-substitution, immuno-gold labeling, electron tomography and immuno-fluorescence microscopy complemented the standard procedures. Liver biopsies showed mislocalization of Rab11 and bile canalicular membrane proteins. Rab11-positive vesicles clustered around bile canaliculi and resembled subapical clusters of aberrant recycling endosomes in enterocytes from MVID patients. The adult patient studied in detail showed a severe, MVID-specific enterocyte phenotype, despite only a mild clinical intestinal presentation. This included mislocalization of numerous proteins essential for apical cargo transport and morphological alterations. We characterized the heterogeneous population of large catabolic organelles regarding their complex ultrastructure and differential distribution of autophagic and lysosomal marker proteins. Finally, we generated duodenal organoids/enteroids from biopsies that recapitulated all MVID hallmarks, demonstrating the potential of this disease model for personalized medicine.
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4
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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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5
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Kusaczuk M. Tauroursodeoxycholate-Bile Acid with Chaperoning Activity: Molecular and Cellular Effects and Therapeutic Perspectives. Cells 2019; 8:E1471. [PMID: 31757001 PMCID: PMC6952947 DOI: 10.3390/cells8121471] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/15/2019] [Accepted: 11/19/2019] [Indexed: 12/11/2022] Open
Abstract
Tauroursodeoxycholic acid (TUDCA) is a naturally occurring hydrophilic bile acid that has been used for centuries in Chinese medicine. Chemically, TUDCA is a taurine conjugate of ursodeoxycholic acid (UDCA), which in contemporary pharmacology is approved by Food and Drug Administration (FDA) for treatment of primary biliary cholangitis. Interestingly, numerous recent studies demonstrate that mechanisms of TUDCA functioning extend beyond hepatobiliary disorders. Thus, TUDCA has been demonstrated to display potential therapeutic benefits in various models of many diseases such as diabetes, obesity, and neurodegenerative diseases, mostly due to its cytoprotective effect. The mechanisms underlying this cytoprotective activity have been mainly attributed to alleviation of endoplasmic reticulum (ER) stress and stabilization of the unfolded protein response (UPR), which contributed to naming TUDCA as a chemical chaperone. Apart from that, TUDCA has also been found to reduce oxidative stress, suppress apoptosis, and decrease inflammation in many in-vitro and in-vivo models of various diseases. The latest research suggests that TUDCA can also play a role as an epigenetic modulator and act as therapeutic agent in certain types of cancer. Nevertheless, despite the massive amount of evidence demonstrating positive effects of TUDCA in pre-clinical studies, there are certain limitations restraining its wide use in patients. Here, molecular and cellular modes of action of TUDCA are described and therapeutic opportunities and limitations of this bile acid are discussed.
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Affiliation(s)
- Magdalena Kusaczuk
- Department of Pharmaceutical Biochemistry, Medical University of Białystok, Mickiewicza 2A, 15-222 Białystok, Poland
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6
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Pan G. Roles of Hepatic Drug Transporters in Drug Disposition and Liver Toxicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1141:293-340. [PMID: 31571168 DOI: 10.1007/978-981-13-7647-4_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatic drug transporters are mainly distributed in parenchymal liver cells (hepatocytes), contributing to drug's liver disposition and elimination. According to their functions, hepatic transporters can be roughly divided into influx and efflux transporters, translocating specific molecules from blood into hepatic cytosol and mediating the excretion of drugs and metabolites from hepatic cytosol to blood or bile, respectively. The function of hepatic transport systems can be affected by interspecies differences and inter-individual variability (polymorphism). In addition, some drugs and disease can redistribute transporters from the cell surface to the intracellular compartments, leading to the changes in the expression and function of transporters. Hepatic drug transporters have been associated with the hepatic toxicity of drugs. Gene polymorphism of transporters and altered transporter expressions and functions due to diseases are found to be susceptible factors for drug-induced liver injury (DILI). In this chapter, the localization of hepatic drug transporters, their regulatory factors, physiological roles, and their roles in drug's liver disposition and DILI are reviewed.
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Affiliation(s)
- Guoyu Pan
- Shanghai Institute of Materia Medica, Chinese Academy of Science, Shanghai, Shanghai, China.
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7
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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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8
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Vauthier V, Ben Saad A, Elie J, Oumata N, Durand-Schneider AM, Bruneau A, Delaunay JL, Housset C, Aït-Slimane T, Meijer L, Falguières T. Structural analogues of roscovitine rescue the intracellular traffic and the function of ER-retained ABCB4 variants in cell models. Sci Rep 2019; 9:6653. [PMID: 31040306 PMCID: PMC6491434 DOI: 10.1038/s41598-019-43111-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/16/2019] [Indexed: 12/12/2022] Open
Abstract
Adenosine triphosphate binding cassette transporter, subfamily B member 4 (ABCB4) is the transporter of phosphatidylcholine at the canalicular membrane of hepatocytes. ABCB4 deficiency, due to genetic variations, is responsible for progressive familial intrahepatic cholestasis type 3 (PFIC3) and other rare biliary diseases. Roscovitine is a molecule in clinical trial that was shown to correct the F508del variant of cystic fibrosis transmembrane conductance regulator (CFTR), another ABC transporter. In the present study, we hypothesized that roscovitine could act as a corrector of ABCB4 traffic-defective variants. Using HEK and HepG2 cells, we showed that roscovitine corrected the traffic and localisation at the plasma membrane of ABCB4-I541F, a prototypical intracellularly retained variant. However, roscovitine caused cytotoxicity, which urged us to synthesize non-toxic structural analogues. Roscovitine analogues were able to correct the intracellular traffic of ABCB4-I541F in HepG2 cells. Importantly, the phospholipid secretion activity of this variant was substantially rescued by three analogues (MRT2-235, MRT2-237 and MRT2-243) in HEK cells. We showed that these analogues also triggered the rescue of intracellular traffic and function of two other intracellularly retained ABCB4 variants, i.e. I490T and L556R. Our results indicate that structural analogues of roscovitine can rescue genetic variations altering the intracellular traffic of ABCB4 and should be considered as therapeutic means for severe biliary diseases caused by this class of variations.
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Affiliation(s)
- Virginie Vauthier
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France
| | - Amel Ben Saad
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France
| | - Jonathan Elie
- ManRos Therapeutics, Hôtel de Recherche, Centre de Perharidy, F-29680, Roscoff, France
| | - Nassima Oumata
- ManRos Therapeutics, Hôtel de Recherche, Centre de Perharidy, F-29680, Roscoff, France
| | - Anne-Marie Durand-Schneider
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France
| | - Alix Bruneau
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France
| | - Jean-Louis Delaunay
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France
| | - Chantal Housset
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France.,Assistance Publique - Hôpitaux de Paris, Hôpital Saint-Antoine, Centre de Référence des Maladies Rares - Maladies Inflammatoires des Voies Biliaires & Service d'Hépatologie, F-75012, Paris, France
| | - Tounsia Aït-Slimane
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France
| | - Laurent Meijer
- ManRos Therapeutics, Hôtel de Recherche, Centre de Perharidy, F-29680, Roscoff, France
| | - Thomas Falguières
- Inserm, Sorbonne Université, Centre de Recherche Saint-Antoine (CRSA), UMR_S 938, Institute of Cardiometabolism and Nutrition (ICAN), F-75012, Paris, France.
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9
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Oliva-Vilarnau N, Hankeova S, Vorrink SU, Mkrtchian S, Andersson ER, Lauschke VM. Calcium Signaling in Liver Injury and Regeneration. Front Med (Lausanne) 2018; 5:192. [PMID: 30023358 PMCID: PMC6039545 DOI: 10.3389/fmed.2018.00192] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/11/2018] [Indexed: 12/12/2022] Open
Abstract
The liver fulfills central roles in metabolic control and detoxification and, as such, is continuously exposed to a plethora of insults. Importantly, the liver has a unique ability to regenerate and can completely recoup from most acute, non-iterative insults. However, multiple conditions, including viral hepatitis, non-alcoholic fatty liver disease (NAFLD), long-term alcohol abuse and chronic use of certain medications, can cause persistent injury in which the regenerative capacity eventually becomes dysfunctional, resulting in hepatic scaring and cirrhosis. Calcium is a versatile secondary messenger that regulates multiple hepatic functions, including lipid and carbohydrate metabolism, as well as bile secretion and choleresis. Accordingly, dysregulation of calcium signaling is a hallmark of both acute and chronic liver diseases. In addition, recent research implicates calcium transients as essential components of liver regeneration. In this review, we provide a comprehensive overview of the role of calcium signaling in liver health and disease and discuss the importance of calcium in the orchestration of the ensuing regenerative response. Furthermore, we highlight similarities and differences in spatiotemporal calcium regulation between liver insults of different etiologies. Finally, we discuss intracellular calcium control as an emerging therapeutic target for liver injury and summarize recent clinical findings of calcium modulation for the treatment of ischemic-reperfusion injury, cholestasis and NAFLD.
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Affiliation(s)
- Nuria Oliva-Vilarnau
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Simona Hankeova
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Sabine U Vorrink
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Souren Mkrtchian
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Emma R Andersson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Volker M Lauschke
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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10
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Zhang W, Chen L, Feng H, Wang W, Cai Y, Qi F, Tao X, Liu J, Shen Y, Ren X, Chen X, Xu J, Shen Y. Rifampicin-induced injury in HepG2 cells is alleviated by TUDCA via increasing bile acid transporters expression and enhancing the Nrf2-mediated adaptive response. Free Radic Biol Med 2017; 112:24-35. [PMID: 28688954 DOI: 10.1016/j.freeradbiomed.2017.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/19/2017] [Accepted: 07/05/2017] [Indexed: 02/07/2023]
Abstract
Bile acid transporters and the nuclear factor erythroid 2-related factor (Nrf-2)-mediated adaptive response play important roles in the development of drug-induced liver injury (DILI). However, little is known about the contribution of the adaptive response to rifampicin (RFP)-induced cell injury. In this study, we found RFP decreased the survival rate of HepG2 cells and increased the levels of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), γ-glutamyl-transferase (γ-GT), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), total bile acid (TBA) and adenosine triphosphate (ATP) in the cell culture supernatants in both a concentration- and a time-dependent manner. RFP increased the expression levels of bile acid transporter proteins and mRNAs, such as bile salt export pump (BSEP), multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2), Na+/taurocholate cotransporter (NTCP), organic anion transporting protein 2 (OATP2), organic solute transporter β (OSTβ) and Nrf2. Following the transient knockdown of Nrf2 and treatment with RFP, the expression levels of the BSEP, MDR1, MRP2, NTCP, OATP2 and OSTβ proteins and mRNAs were decreased to different degrees. Moreover, the cell survival was decreased, whereas the LDH level in the cell culture supernatant was increased. Overexpression of the Nrf2 gene produced the opposite effects. Treatment with tauroursodeoxycholic acid (TUDCA) increased the expression levels of the bile acid transporters and Nrf2, decreased the expression levels of glucose-regulated protein 78 (GRP78), PKR-like ER kinase (PERK), activating transcription factor 4 (ATF4), and C/EBP-homologous protein (CHOP), and inhibited RFP-induced oxidative stress. Moreover, TUDCA reduced cell apoptosis, increased cell survival and decreased the levels of LDH, ALT, AST, AKP, γ-GT, TBIL, DBIL, IBIL, TBA and ATP in the cell culture supernatant. Therefore, TUDCA alleviates RFP-induced injury in HepG2 cells by enhancing bile acid transporters expression and the Nrf2-mediated adaptive response.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/agonists
- ATP Binding Cassette Transporter, Subfamily B/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 11/agonists
- ATP Binding Cassette Transporter, Subfamily B, Member 11/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 11/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 11/metabolism
- Adaptation, Physiological
- Adenosine Triphosphate
- Alanine Transaminase/genetics
- Alanine Transaminase/metabolism
- Alkaline Phosphatase/genetics
- Alkaline Phosphatase/metabolism
- Antibiotics, Antitubercular/pharmacology
- Aspartate Aminotransferases/genetics
- Aspartate Aminotransferases/metabolism
- Bilirubin
- Endoplasmic Reticulum Chaperone BiP
- Gene Expression Regulation
- Hep G2 Cells
- Humans
- L-Lactate Dehydrogenase/genetics
- L-Lactate Dehydrogenase/metabolism
- Liver-Specific Organic Anion Transporter 1/genetics
- Liver-Specific Organic Anion Transporter 1/metabolism
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Multidrug Resistance-Associated Protein 2
- Multidrug Resistance-Associated Proteins/agonists
- Multidrug Resistance-Associated Proteins/antagonists & inhibitors
- Multidrug Resistance-Associated Proteins/genetics
- Multidrug Resistance-Associated Proteins/metabolism
- NF-E2-Related Factor 2/agonists
- NF-E2-Related Factor 2/genetics
- NF-E2-Related Factor 2/metabolism
- Organic Anion Transporters, Sodium-Dependent/genetics
- Organic Anion Transporters, Sodium-Dependent/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rifampin/antagonists & inhibitors
- Rifampin/pharmacology
- Signal Transduction
- Stress, Physiological
- Symporters/genetics
- Symporters/metabolism
- Taurochenodeoxycholic Acid/pharmacology
- gamma-Glutamyltransferase/genetics
- gamma-Glutamyltransferase/metabolism
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Affiliation(s)
- Weiping Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China; The First Affliated Hospital of AUTCM, 117 Meishan Road, Hefei 230031, People's Republic of China
| | - Lihong Chen
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Hui Feng
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Wei Wang
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Yi Cai
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Fen Qi
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Xiaofang Tao
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China; Biopharmaceutical Institute, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China
| | - Jun Liu
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China; Biopharmaceutical Institute, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China
| | - Yujun Shen
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China; Biopharmaceutical Institute, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China
| | - Xiaofei Ren
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Xi Chen
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China
| | - Jianming Xu
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei 230022, People's Republic of China.
| | - Yuxian Shen
- School of Basic Medical Sciences, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China; Biopharmaceutical Institute, Anhui Medical University, 81 Meishan Road, Hefei 230032, People's Republic of China.
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11
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Cariello M, Piccinin E, Garcia-Irigoyen O, Sabbà C, Moschetta A. Nuclear receptor FXR, bile acids and liver damage: Introducing the progressive familial intrahepatic cholestasis with FXR mutations. Biochim Biophys Acta Mol Basis Dis 2017; 1864:1308-1318. [PMID: 28965883 DOI: 10.1016/j.bbadis.2017.09.019] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/15/2017] [Accepted: 09/17/2017] [Indexed: 02/07/2023]
Abstract
The nuclear receptor farnesoid X receptor (FXR) is the master regulator of bile acids (BAs) homeostasis since it transcriptionally drives modulation of BA synthesis, influx, efflux, and detoxification along the enterohepatic axis. Due to its crucial role, FXR alterations are involved in the progression of a plethora of BAs associated inflammatory disorders in the liver and in the gut. The involvement of the FXR pathway in cholestasis development and management has been elucidated so far with a direct role of FXR activating therapy in this condition. However, the recent identification of a new type of genetic progressive familial intrahepatic cholestasis (PFIC) linked to FXR mutations has strengthen also the bona fide beneficial effects of target therapies that by-pass FXR activation, directly promoting the action of its target, namely the enterokine FGF19, in the repression of hepatic BAs synthesis with reduction of total BA levels in the liver and serum, accomplishing one of the major goals in cholestasis. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni and Peter Jansen.
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Affiliation(s)
- Marica Cariello
- Department of Interdisciplinary Medicine, "Aldo Moro" University of Bari, 70124 Bari, Italy
| | - Elena Piccinin
- INBB, National Institute for Biostructures and Biosystems, 00136 Rome, Italy
| | - Oihane Garcia-Irigoyen
- Department of Interdisciplinary Medicine, "Aldo Moro" University of Bari, 70124 Bari, Italy
| | - Carlo Sabbà
- Department of Interdisciplinary Medicine, "Aldo Moro" University of Bari, 70124 Bari, Italy
| | - Antonio Moschetta
- Department of Interdisciplinary Medicine, "Aldo Moro" University of Bari, 70124 Bari, Italy; National Cancer Center, IRCCS Istituto Oncologico "Giovanni Paolo II", 70124 Bari, Italy.
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12
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Hou Y, Yang H, Cui Z, Tai X, Chu Y, Guo X. Tauroursodeoxycholic acid attenuates endoplasmic reticulum stress and protects the liver from chronic intermittent hypoxia induced injury. Exp Ther Med 2017; 14:2461-2468. [PMID: 28962181 PMCID: PMC5609300 DOI: 10.3892/etm.2017.4804] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 03/10/2017] [Indexed: 01/14/2023] Open
Abstract
Obstructive sleep apnea that characterized by chronic intermittent hypoxia (CIH) has been reported to associate with chronic liver injury. Tauroursodeoxycholic acid (TUDCA) exerts liver-protective effects in various liver diseases. The purpose of this study was to test the hypothesis that TUDCA could protect liver against CIH injury. C57BL/6 mice were subjected to intermittent hypoxia for eight weeks and applied with TUDCA by intraperitoneal injection. The effect of TUDCA on liver histological changes, liver function, oxidative stress, inflammatory response, hepatocyte apoptosis and endoplasmic reticulum (ER) stress were investigated. The results showed that administration of TUDCA attenuated liver pathological changes, reduced serum alanine aminotransferase and aspartate aminotransferase level, suppressed reactive oxygen species activity, decreased tumor necrosis factor-α and interleukin-1β level and inhibited hepatocyte apoptosis induced by CIH. TUDCA also inhibited CIH-induced ER stress in liver as evidenced by decreased expression of ER chaperone 78 kDa glucose-related protein, unfolded protein response transducers and ER proapoptotic proteins. Altogether, the present study described a liver-protective effect of TUDCA in CIH mice model, and this effect seems at least partly through the inhibition of ER stress.
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Affiliation(s)
- Yanpeng Hou
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.,Department of Otolaryngology, The 463rd Hospital of The Chinese People's Liberation Army, Shenyang, Liaoning 110042, P.R. China
| | - Huai'an Yang
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Zeshi Cui
- Science Experiment Center of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Xuhui Tai
- Department of Otolaryngology, The 463rd Hospital of The Chinese People's Liberation Army, Shenyang, Liaoning 110042, P.R. China
| | - Yanling Chu
- Department of Otolaryngology, The 463rd Hospital of The Chinese People's Liberation Army, Shenyang, Liaoning 110042, P.R. China
| | - Xing Guo
- Department of Otolaryngology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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Léon C, Dupuis A, Gachet C, Lanza F. The contribution of mouse models to the understanding of constitutional thrombocytopenia. Haematologica 2017; 101:896-908. [PMID: 27478199 DOI: 10.3324/haematol.2015.139394] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/04/2016] [Indexed: 11/09/2022] Open
Abstract
Constitutional thrombocytopenias result from platelet production abnormalities of hereditary origin. Long misdiagnosed and poorly studied, knowledge about these rare diseases has increased considerably over the last twenty years due to improved technology for the identification of mutations, as well as an improvement in obtaining megakaryocyte culture from patient hematopoietic stem cells. Simultaneously, the manipulation of mouse genes (transgenesis, total or conditional inactivation, introduction of point mutations, random chemical mutagenesis) have helped to generate disease models that have contributed greatly to deciphering patient clinical and laboratory features. Most of the thrombocytopenias for which the mutated genes have been identified now have a murine model counterpart. This review focuses on the contribution that these mouse models have brought to the understanding of hereditary thrombocytopenias with respect to what was known in humans. Animal models have either i) provided novel information on the molecular and cellular pathways that were missing from the patient studies; ii) improved our understanding of the mechanisms of thrombocytopoiesis; iii) been instrumental in structure-function studies of the mutated gene products; and iv) been an invaluable tool as preclinical models to test new drugs or develop gene therapies. At present, the genetic determinants of thrombocytopenia remain unknown in almost half of all cases. Currently available high-speed sequencing techniques will identify new candidate genes, which will in turn allow the generation of murine models to confirm and further study the abnormal phenotype. In a complementary manner, programs of random mutagenesis in mice should also identify new candidate genes involved in thrombocytopenia.
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Affiliation(s)
- Catherine Léon
- UMR_S949, INSERM, Strasbourg, France Etablissement Français du Sang-Alsace (EFS-Alsace), Strasbourg, France Université de Strasbourg, France Fédération de Médecine Translationnelle de Strasbourg (FMTS), France
| | - Arnaud Dupuis
- UMR_S949, INSERM, Strasbourg, France Etablissement Français du Sang-Alsace (EFS-Alsace), Strasbourg, France Université de Strasbourg, France Fédération de Médecine Translationnelle de Strasbourg (FMTS), France
| | - Christian Gachet
- UMR_S949, INSERM, Strasbourg, France Etablissement Français du Sang-Alsace (EFS-Alsace), Strasbourg, France Université de Strasbourg, France Fédération de Médecine Translationnelle de Strasbourg (FMTS), France
| | - François Lanza
- UMR_S949, INSERM, Strasbourg, France Etablissement Français du Sang-Alsace (EFS-Alsace), Strasbourg, France Université de Strasbourg, France Fédération de Médecine Translationnelle de Strasbourg (FMTS), France
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14
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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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15
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van der Woerd WL, Houwen RHJ, van de Graaf SFJ. Current and future therapies for inherited cholestatic liver diseases. World J Gastroenterol 2017; 23:763-775. [PMID: 28223721 PMCID: PMC5296193 DOI: 10.3748/wjg.v23.i5.763] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/16/2016] [Accepted: 01/11/2017] [Indexed: 02/06/2023] Open
Abstract
Familial intrahepatic cholestasis (FIC) comprises a group of rare cholestatic liver diseases associated with canalicular transport defects resulting predominantly from mutations in ATP8B1, ABCB11 and ABCB4. Phenotypes range from benign recurrent intrahepatic cholestasis (BRIC), associated with recurrent cholestatic attacks, to progressive FIC (PFIC). Patients often suffer from severe pruritus and eventually progressive cholestasis results in liver failure. Currently, first-line treatment includes ursodeoxycholic acid in patients with ABCB4 deficiency (PFIC3) and partial biliary diversion in patients with ATP8B1 or ABCB11 deficiency (PFIC1 and PFIC2). When treatment fails, liver transplantation is needed which is associated with complications like rejection, post-transplant hepatic steatosis and recurrence of disease. Therefore, the need for more and better therapies for this group of chronic diseases remains. Here, we discuss new symptomatic treatment options like total biliary diversion, pharmacological diversion of bile acids and hepatocyte transplantation. Furthermore, we focus on emerging mutation-targeted therapeutic strategies, providing an outlook for future personalized treatment for inherited cholestatic liver diseases.
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16
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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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18
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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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Cermanova J, Kadova Z, Zagorova M, Hroch M, Tomsik P, Nachtigal P, Kudlackova Z, Pavek P, Dubecka M, Ceckova M, Staud F, Laho T, Micuda S. Boldine enhances bile production in rats via osmotic and farnesoid X receptor dependent mechanisms. Toxicol Appl Pharmacol 2015; 285:12-22. [PMID: 25771127 DOI: 10.1016/j.taap.2015.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/26/2015] [Accepted: 03/03/2015] [Indexed: 12/22/2022]
Abstract
Boldine, the major alkaloid from the Chilean Boldo tree, is used in traditional medicine to support bile production, but evidence to support this function is controversial. We analyzed the choleretic potential of boldine, including its molecular background. The acute- and long-term effects of boldine were evaluated in rats either during intravenous infusion or after 28-day oral treatment. Infusion of boldine instantly increased the bile flow 1.4-fold in healthy rats as well as in animals with Mrp2 deficiency or ethinylestradiol induced cholestasis. This effect was not associated with a corresponding increase in bile acid or glutathione biliary excretion, indicating that the effect is not related to stimulation of either bile acid dependent or independent mechanisms of bile formation and points to the osmotic activity of boldine itself. We subsequently analyzed bile production under conditions of changing biliary excretion of boldine after bolus intravenous administration and found strong correlations between both parameters. HPLC analysis showed that bile concentrations of boldine above 10 μM were required for induction of choleresis. Importantly, long-term pretreatment, when the bile collection study was performed 24-h after the last administration of boldine, also accelerated bile formation despite undetectable levels of the compound in bile. The effect paralleled upregulation of the Bsep transporter and increased biliary clearance of its substrates, bile acids. We consequently confirmed the ability of boldine to stimulate the Bsep transcriptional regulator, FXR receptor. In conclusion, our study clarified the mechanisms and circumstances surrounding the choleretic activity of boldine.
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Affiliation(s)
- Jolana Cermanova
- Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Zuzana Kadova
- Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic; Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Marie Zagorova
- Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Milos Hroch
- Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic; Department of Medical Biochemistry, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Pavel Tomsik
- Department of Medical Biochemistry, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Petr Nachtigal
- Department of Biological and Medical Sciences, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Zdenka Kudlackova
- Department of Biological and Medical Sciences, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Petr Pavek
- Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Michaela Dubecka
- Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Martina Ceckova
- Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Frantisek Staud
- Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove, Czech Republic
| | - Tomas Laho
- Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Stanislav Micuda
- Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove, Czech Republic.
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20
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Dyson JK, Hirschfield GM, Adams DH, Beuers U, Mann DA, Lindor KD, Jones DEJ. Novel therapeutic targets in primary biliary cirrhosis. Nat Rev Gastroenterol Hepatol 2015; 12:147-58. [PMID: 25645973 DOI: 10.1038/nrgastro.2015.12] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Primary biliary cirrhosis (PBC) is a chronic immune-mediated liver disease characterized by progressive cholestasis, biliary fibrosis and eventually cirrhosis. It results in characteristic symptoms with marked effects on life quality. The advent of large patient cohorts has challenged the view of PBC as a benign condition treated effectively by the single licensed therapy-ursodeoxycholic acid (UDCA). UDCA nonresponse or under-response has a major bearing on outcome, substantially increasing the likelihood that liver transplantation will be required or that patients will die of the disease. In patients with high-risk, treatment-unresponsive or highly symptomatic disease the need for new treatment approaches is clear. Evolution in our understanding of disease mechanisms is rapidly leading to the advent of new and re-purposed therapeutic agents targeting key processes. Notable opportunities are offered by targeting what could be considered as the 'upstream' immune response, 'midstream' biliary injury and 'downstream' fibrotic processes. Combination therapy targeting several pathways or the development of novel agents addressing multiple components of the disease pathway might be required. Ultimately, PBC therapeutics will require a stratified approach to be adopted in practice. This Review provides a current perspective on potential approaches to PBC treatment, and highlights the challenges faced in evaluating and implementing those treatments.
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Affiliation(s)
- Jessica K Dyson
- Institute of Cellular Medicine, 3rd Floor William Leech Building, Medical School, Framlington Place, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Gideon M Hirschfield
- Centre for Liver Research, NIHR Biomedical Research Unit, University of Birmingham, Wolfson Drive, Birmingham B15 2TT, UK
| | - David H Adams
- Centre for Liver Research, NIHR Biomedical Research Unit, University of Birmingham, Wolfson Drive, Birmingham B15 2TT, UK
| | - Ulrich Beuers
- Department of Gastroenterology &Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, G4-216, University of Amsterdam, PO Box 22600, NL-1100 DD, Amsterdam, Netherlands
| | - Derek A Mann
- Institute of Cellular Medicine, 3rd Floor William Leech Building, Medical School, Framlington Place, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Keith D Lindor
- College of Health Solutions, Arizona State University, 550 North 3rd Street, Phoenix, AZ 85004, USA
| | - David E J Jones
- Institute of Cellular Medicine, 3rd Floor William Leech Building, Medical School, Framlington Place, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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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: 49] [Impact Index Per Article: 4.9] [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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22
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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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23
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Zinchuk V, Grossenbacher-Zinchuk O. Quantitative colocalization analysis of fluorescence microscopy images. CURRENT PROTOCOLS IN CELL BIOLOGY 2014; 62:4.19.1-4.19.14. [PMID: 24610126 DOI: 10.1002/0471143030.cb0419s62] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Colocalization is an important finding in many cell biological studies. This unit describes a protocol for quantitative evaluation of fluorescence microscopy images with colocalization based on calculation of a number of specialized coefficients. Images of double-stained sections are first subjected to background correction, and then various coefficients are calculated. Meanings of the coefficients and a guide to interpretation of the results of calculations based on the use of linguistic variables are given. Success in colocalization studies depends on the quality of images analyzed, proper preparation of the images for coefficients calculations, and correct interpretation of results obtained. This protocol helps ensure reliability of colocalization coefficient calculations.
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Affiliation(s)
- Vadim Zinchuk
- Department of Neurobiology and Anatomy, Kochi University, Faculty of Medicine, Japan
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24
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Pollheimer MJ, Fickert P, Stieger B. Chronic cholestatic liver diseases: clues from histopathology for pathogenesis. Mol Aspects Med 2013; 37:35-56. [PMID: 24141039 DOI: 10.1016/j.mam.2013.10.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 02/06/2023]
Abstract
Chronic cholestatic liver diseases include fibrosing cholangiopathies such as primary biliary cirrhosis or primary sclerosing cholangitis. These and related cholangiopathies clearly display pathologies associated with (auto)immunologic processes. As the cholangiocyte's apical membrane is exposed to the toxic actions of the bile fluid, the interaction of bile with cholangiocytes and the biliary tree in general must be considered to completely understand the pathogenesis of cholangiopathies. While the molecular processes involved in the hepatocellular formation of bile are well understood in both normal and pathophysiologic conditions, those in the bile ducts of normal liver and in livers with cholangiopathies lag behind. This survey highlights key mechanisms known to date that are important for the formation of bile by hepatocytes and its modification by the biliary tree. It also delineates the clinical pathophysiologic findings for cholangiopathies and puts them in perspective with current experimental models to reveal the pathogenesis of cholangiopathies and develop novel therapeutic approaches.
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Affiliation(s)
- Marion J Pollheimer
- Division of Gastroenterology and Hepatology, Laboratory of Experimental and Molecular Hepatology, Department of Internal Medicine, Medical University of Graz, Austria; Institute of Pathology, Medical University of Graz, Austria
| | - Peter Fickert
- Division of Gastroenterology and Hepatology, Laboratory of Experimental and Molecular Hepatology, Department of Internal Medicine, Medical University of Graz, Austria; Institute of Pathology, Medical University of Graz, Austria.
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland.
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Beuers U. β1 integrin is a long-sought sensor for tauroursodeoxycholic acid. Hepatology 2013; 57:867-9. [PMID: 23456677 DOI: 10.1002/hep.26228] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 01/20/2023]
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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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Maillette de Buy Wenniger LJ, Oude Elferink RP, Beuers U. Molecular targets for the treatment of fibrosing cholangiopathies. Clin Pharmacol Ther 2012; 92:381-7. [PMID: 22850600 DOI: 10.1038/clpt.2012.111] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Emerging pathophysiologic insights are leading to novel approaches to treating fibrosing cholangiopathies. The current treatment, using ursodeoxycholic acid (UDCA), may slow the progression of some chronic cholangiopathies but cannot heal them. Apart from immunosuppressive interventions aimed at minimizing immune-mediated damage, the use of specific modifiers of hepatobiliary secretory and cytoprotective mechanisms may eventually give rise to a new class of disease-modifying anti-cholangiofibrotic drugs.
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Affiliation(s)
- L J Maillette de Buy Wenniger
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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4-Phenylbutyrate modulates ubiquitination of hepatocanalicular MRP2 and reduces serum total bilirubin concentration. J Hepatol 2012; 56:1136-1144. [PMID: 22245901 DOI: 10.1016/j.jhep.2011.11.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 11/25/2011] [Accepted: 11/28/2011] [Indexed: 01/08/2023]
Abstract
BACKGROUND & AIMS Multidrug resistance-associated protein 2 (in humans, MRP2; in rodents, Mrp2) mediates biliary excretion of bilirubin glucuronides. Therefore, upregulation of MRP2/Mrp2 expression may improve hyperbilirubinemia. We investigated the effects of 4-phenylbutyrate (4PBA), a drug used to treat ornithine transcarbamylase deficiency (OTCD), on the cell surface expression and transport function of MRP2/Mrp2 and serum T-Bil concentration. METHODS MRP2-expressing MDCKII (MRP2-MDCKII) cells and rats were studied to explore the change induced by 4PBA treatment in the cell surface expression and transport function of MRP2/Mrp2 and its underlying mechanism. Serum and liver specimens from OTCD patients were analyzed to examine the effect of 4PBA on hepatic MRP2 expression and serum T-Bil concentration in humans. RESULTS In MRP2-MDCKII cells and the rat liver, 4PBA increased the cell surface expression and transport function of MRP2/Mrp2. In patients with OTCD, hepatic MRP2 expression increased and serum T-Bil concentration decreased significantly after 4PBA treatment. In vitro studies designed to explore the mechanism underlying this drug action suggested that cell surface-resident MRP2/Mrp2 is degraded via ubiquitination-mediated targeting to the endosomal/lysosomal degradation pathway and that 4PBA inhibits the degradation of cell surface-resident MRP2/Mrp2 by reducing its susceptibility to ubiquitination. CONCLUSIONS 4PBA activates MRP2/Mrp2 function through increased expression of MRP2/Mrp2 at the hepatocanalicular membrane by modulating its ubiquitination, and thereby decreases serum T-Bil concentration. 4PBA has thus therapeutic potential for improving hyperbilirubinemia.
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Romiplostim administration shows reduced megakaryocyte response-capacity and increased myelofibrosis in a mouse model of MYH9-RD. Blood 2012; 119:3333-41. [DOI: 10.1182/blood-2011-08-373811] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Abstract
Macrothrombocytopenia in MYH9-related disease (MYH9-RD) results from defects in nonmuscular myosin-IIA function. Thrombopoietin receptor agonists (eltrombopag; romiplostim) seem to improve hemostasis, but little is known about their biologic effects in MYH9-RD. We administered romiplostim to Myh9−/− mice (100 μg/kg, every 3 days, during 1 month). MKs increased to similar numbers in Myh9−/− and wild-type (WT) mice (with an increase in immature MKs), but Myh9−/− platelet count response was much less (2.5-fold vs 8-fold increase). A strong increase in MK nuclei emboli in the lung, in WT and Myh9−/− mice, indicates increased transmigration of MKs from the BM. Prolonged (but not acute) treatment with romiplostim decreased expression of GPIb-IX-V complex and GPVI, but not of GPIIbIIIa, and bleeding time increased in WT mice. Microcirculation was not altered by the increased number of large platelets in any of the assessed organs, but in Myh9−/− mice a much stronger increase in BM reticulin fibers was present after 4 weeks of romiplostim treatment vs WT mice. These data further encourage short-term use of thrombopoietic agents in patients with MYH9-RDs; however, myelofibrosis has to be considered as a potential severe adverse effect during longer treatment. Reduction of GPIbIX/GPVI expression by romiplostim requires further studies.
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Kruglov EA, Gautam S, Guerra MT, Nathanson MH. Type 2 inositol 1,4,5-trisphosphate receptor modulates bile salt export pump activity in rat hepatocytes. Hepatology 2011; 54:1790-9. [PMID: 21748767 PMCID: PMC3205211 DOI: 10.1002/hep.24548] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 06/26/2011] [Indexed: 12/16/2022]
Abstract
UNLABELLED Bile salt secretion is mediated primarily by the bile salt export pump (Bsep), a transporter on the canalicular membrane of the hepatocyte. However, little is known about the short-term regulation of Bsep activity. Ca(2+) regulates targeting and insertion of transporters in many cell systems, and Ca(2+) release near the canalicular membrane is mediated by the type II inositol 1,4,5-trisphosphate receptor (InsP3R2), so we investigated the possible role of InsP3R2 in modulating Bsep activity. The kinetics of Bsep activity were monitored by following secretion of the fluorescent Bsep substrate cholylglycylamido-fluorescein (CGamF) in rat hepatocytes in collagen sandwich culture, an isolated cell system in which structural and functional polarity is preserved. CGamF secretion was nearly eliminated in cells treated with Bsep small interfering RNA (siRNA), demonstrating specificity of this substrate for Bsep. Secretion was also reduced after chelating intracellular calcium, inducing redistribution of InsP3R2 by depleting the cell membrane of cholesterol, or reducing InsP3R function by either knocking down InsP3R2 expression using siRNA or pharmacologic inhibition using xestospongin C. Confocal immunofluorescence showed that InsP3R2 and Bsep are in close proximity in the canalicular region, both in rat liver and in hepatocytes in sandwich culture. However, after knocking down InsP3R2 or inducing its dysfunction with cholesterol depletion, Bsep redistributed intracellularly. Finally, InsP3R2 was lost from the pericanalicular region in animal models of estrogen- and endotoxin-induced cholestasis. CONCLUSION These data provide evidence that pericanalicular calcium signaling mediated by InsP3R2 plays an important role in maintaining bile salt secretion through posttranslational regulation of Bsep, and suggest that loss or redistribution of InsP3R2 may contribute to the pathophysiology of intrahepatic cholestasis.
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Affiliation(s)
| | | | | | - Michael H. Nathanson
- Address for correspondence: Michael H. Nathanson, Section of Digestive Diseases, Yale University School of Medicine, 333 Cedar Street, TAC S241D, New Haven, CT. 06520-8019, Phone: (203) 785-7312. Fax: (203) 785-7273
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31
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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: 125] [Impact Index Per Article: 9.6] [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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Zinchuk V, Grossenbacher‐Zinchuk O. Quantitative Colocalization Analysis of Confocal Fluorescence Microscopy Images. ACTA ACUST UNITED AC 2011; Chapter 4:Unit4.19. [DOI: 10.1002/0471143030.cb0419s52] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Vadim Zinchuk
- Department of Anatomy and Cell Biology, Kochi University Faculty of Medicine Japan
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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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34
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Denk GU, Maitz S, Wimmer R, Rust C, Invernizzi P, Ferdinandusse S, Kulik W, Fuchsbichler A, Fickert P, Trauner M, Hofmann AF, Beuers U. Conjugation is essential for the anticholestatic effect of NorUrsodeoxycholic acid in taurolithocholic acid-induced cholestasis in rat liver. Hepatology 2010; 52:1758-68. [PMID: 21038414 DOI: 10.1002/hep.23911] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
UNLABELLED NorUDCA (24-norursodeoxycholic acid), the C₂₃-homolog of ursodeoxycholic acid (UDCA), showed remarkable therapeutic effects in cholestatic Mdr2 (Abcb4) (multidrug resistance protein 2/ATP-binding cassette b4) knockout mice with sclerosing/fibrosing cholangitis. In contrast to UDCA, norUDCA is inefficiently conjugated in human and rodent liver, and conjugation has been discussed as a key step for the anticholestatic action of UDCA in cholestasis. We compared the choleretic, anticholestatic, and antiapoptotic properties of unconjugated and taurine-conjugated UDCA (C₂₄) and norUDCA (C₂₃) in isolated perfused rat liver (IPRL) and in natrium/taurocholate cotransporting polypeptide (Ntcp)-transfected human hepatoma (HepG2) cells. Taurolithocholic acid (TLCA) was used to induce a predominantly hepatocellular cholestasis in IPRL. Bile flow was determined gravimetrically; bile acids determined by gas chromatography and liquid chromatography/tandem mass spectrometry; the Mrp2 model substrate, 2,4-dinitrophenyl-S-glutathione (GS-DNP) was determined spectrophotometrically; and apoptosis was determined immunocytochemically. The choleretic effect of C₂₃-bile acids was comparable to their C₂₄-homologs in IPRL. In contrast, TnorUDCA, but not norUDCA antagonized the cholestatic effect of TLCA. Bile flow (percent of controls) was 8% with TLCA-induced cholestasis, and unchanged by coinfusion of norUDCA (14%). However, it was increased by TnorUDCA (83%), UDCA (73%) and TUDCA (136%). Secretion of GS-DNP was markedly reduced by TLCA (5%), unimproved by norUDCA (4%) or UDCA (17%), but was improved modestly by TnorUDCA (26%) or TUDCA (58%). No apoptosis was observed in IPRL exposed to low micromolar TLCA, but equivalent antiapoptotic effects of TUDCA and TnorUDCA were observed in Ntcp-HepG2 cells exposed to TLCA. CONCLUSION Conjugation is essential for the anticholestatic effect of norUDCA in a model of hepatocellular cholestasis. Combined therapy with UDCA and norUDCA may be superior to UDCA or norUDCA monotherapy in biliary disorders in which hepatocyte as well as cholangiocyte dysfunction contribute to disease progression.
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Affiliation(s)
- Gerald U Denk
- Department of Medicine II, Klinikum Großhadern, University of Munich, Munich, Germany
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Beuers U, Hohenester S, de Buy Wenniger LJM, Kremer AE, Jansen PLM, Elferink RPJO. The biliary HCO(3)(-) umbrella: a unifying hypothesis on pathogenetic and therapeutic aspects of fibrosing cholangiopathies. Hepatology 2010; 52:1489-96. [PMID: 20721884 DOI: 10.1002/hep.23810] [Citation(s) in RCA: 248] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review focuses on the hypothesis that biliary HCO(3)(-) secretion in humans serves to maintain an alkaline pH near the apical surface of hepatocytes and cholangiocytes to prevent the uncontrolled membrane permeation of protonated glycine-conjugated bile acids. Functional impairment of this biliary HCO(3)(-) umbrella or its regulation may lead to enhanced vulnerability of cholangiocytes and periportal hepatocytes toward the attack of apolar hydrophobic bile acids. An intact interplay of hepatocellular and cholangiocellular adenosine triphosphate (ATP) secretion, ATP/P2Y- and bile salt/TGR5-mediated Cl(-)/ HCO(3)(-) exchange and HCO(3)(-) secretion, and alkaline phosphatase-mediated ATP breakdown may guarantee a stable biliary HCO(3)(-) umbrella under physiological conditions. Genetic and acquired functional defects leading to destabilization of the biliary HCO(3)(-) umbrella may contribute to development and progression of various forms of fibrosing/sclerosing cholangitis.
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Affiliation(s)
- Ulrich Beuers
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Wang D, Yang L, Huang JM, Wang BY, Li L, Qian W, Ye J, Hou XH. Tauroursodeoxycholic acid inhibits carbon tetrachloride-induced liver fibrosis in rats. Shijie Huaren Xiaohua Zazhi 2010; 18:1979-1984. [DOI: 10.11569/wcjd.v18.i19.1979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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
AIM: To determine the inhibitory effects of tauroursodeoxycholic acid (TUDCA) on carbon tetrachloride-induced liver fibrosis in rats.
METHODS: A total of 75 healthy Sprague-Dawley rats were randomly divided into five groups: normal control group, model group, low-dose TUDCA group, high-dose TUDCA group and pentoxifylline (PTX) group. Hepatic fibrosis was induced in rats by hypodermic injection of carbon tetrachloride (40%). The low- and high-dose TUDCA groups were orally administered TUDCA at doses of 50 and 100 mg/(kg•d), respectively. The PTX group was orally administered PTX at a dose of 16 mg/(kg•d). The treatment lasted 8 wk for all the groups. Hematoxylin and eosin staining and Masson's trichrome staining of liver tissue was performed for histopathological evaluation of liver fibrosis. Serum parameters of liver fibrosis were detected by enzyme-linked immunosorbent assay. The expression of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in liver tissue was detected by immunohistochemistry.
RESULTS: Compared with the model group, the levels of serum hyaluronic acid (HA), laminin (LN) and type IV collagen (IV-C) significantly decreased in the low- and high-dose TUDCA groups and the PTX group (HA: 146.33 ± 35.13, 162.2 ± 24.80 and 137.14 ± 22.24 vs 252.83 ± 51.94; LN: 77.20 ± 11.84, 66.80 ± 16.78 and 82.00 ± 10.74 vs 108.00 ± 30.00; IV-C: 14.14 ± 2.59, 12.60 ± 3.17 and 10.09 ± 2.22 vs 25.08 ± 5.93, all P < 0.05). Compared with the model group and normal control group, fibrous septa became thinner and even disappeared, and the number of diffuse cirrhotic nodules and the area of collagen fiber decreased in the TUDCA and PTX intervention groups (all P < 0.05). The expression intensity of TGF-β1 and α-SMA proteins was significantly lower in the TUDCA and PTX intervention groups than in the model group (all P < 0.05), but showed no significant difference between the TUDCA and PTX treatment groups.
CONCLUSION: TUDCA can prevent carbon tetrachloride-induced liver fibrosis in rats by reducing TGF-β1 synthesis, inhibiting hepatic stellate cell activation and decreasing extracellular matrix synthesis.
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Maillette de Buy Wenniger L, Beuers U. Bile salts and cholestasis. Dig Liver Dis 2010; 42:409-18. [PMID: 20434968 DOI: 10.1016/j.dld.2010.03.015] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 03/13/2010] [Indexed: 12/11/2022]
Abstract
Bile salts have a crucial role in hepatobiliary and intestinal homeostasis and digestion. Primary bile salts are synthesized by the liver from cholesterol, and may be modified by the intestinal flora to form secondary and tertiary bile salts. Bile salts are efficiently reabsorbed from the intestinal lumen to undergo enterohepatic circulation. In addition to their function as a surfactant involved in the absorption of dietary lipids and fat-soluble vitamins bile salts are potent signaling molecules in both the liver and intestine. Under physiological conditions the bile salt pool is tightly regulated, but the adaptive capacity may fall short under cholestatic conditions. Elevated serum and tissue levels of potentially toxic hydrophobic bile salts during cholestasis may cause mitochondrial damage, apoptosis or necrosis in susceptible cell types. Therapeutic nontoxic bile salts may restore impaired hepatobiliary secretion in cholestatic disorders. The hydrophilic bile salt ursodeoxycholate is today regarded as the effective standard treatment of primary biliary cirrhosis and intrahepatic cholestasis of pregnancy, and is implicated for use in various other cholestatic conditions. Novel therapeutic bile salts that are currently under evaluation may also prove valuable in the treatment of these diseases.
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Affiliation(s)
- Lucas Maillette de Buy Wenniger
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, The Netherlands
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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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Abstract
A review is presented of Gustav Paumgartner's five decades of research and practice in hepatology focusing on biliary physiology and disease. It begins with studies of the excretory function of the liver including hepatic uptake of indocyanine green, bilirubin, and bile acids. The implications of these studies for diagnosis and understanding of liver diseases are pointed out. From there, the path of scientific research leads to investigations of hepatobiliary bile acid transport and the major mechanisms of bile formation. The therapeutic effects of the hydrophilic bile acid, ursodeoxycholic acid, have greatly stimulated these studies. Although ursodeoxycholic acid therapy for dissolution of cholesterol gallstones and some other nonsurgical treatments of gallstones were largely superseded by surgical techniques, ursodeoxycholic acid is currently considered the mainstay of therapy of some chronic cholestatic liver diseases, such as primary biliary cirrhosis. The major mechanisms of action of ursodeoxycholic acid therapy in cholestatic liver diseases are discussed. An attempt is made to illustrate how scientific research can lead to advances in medical practice that help patients.
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Affiliation(s)
- Gustav Paumgartner
- Department of Medicine II, Klinikum Grosshadern, University of Munich, Munich, Germany.
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40
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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
PURPOSE OF REVIEW Generation of bile is an important function of the liver. Its impairment can be caused by inherited mutations or by acquired factors and leads to cholestasis. Bile salts are an important constituent of bile and are secreted by the bile salt export pump (BSEP) from hepatocytes. RECENT FINDINGS Significant progress was made in the understanding of mechanisms and consequences of malfunctioning BSEP. This information was gained from extensive characterization of patients with inherited BSEP deficiency and the subsequent characterization of the identified mutations in heterologous expression systems. Furthermore and importantly, clinical evidence shows that patients with severe BSEP deficiency are at risk to develop hepatocellular carcinoma. Bile salts are now recognized to be important in the modulation of whole body energy homeostasis. Because BSEP is the rate-limiting step in hepatocellular bile salt transport, it controls the spill over of bile salts into the systemic circulation. Therefore, an indirect role of BSEP in energy homeostasis becomes more and more likely. SUMMARY In summary, knowledge on the physiologic and pathophysiologic role of BSEP is rapidly progressing. It can be anticipated that the next major step in better understanding BSEP should come from information on structure-function relationship. However, given the difficulty in structure determination of mammalian transporters, this will require major efforts.
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Affiliation(s)
- Bruno Stieger
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, University Hospital, Zurich, Switzerland.
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42
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Ismair MG, Häusler S, Stuermer CA, Guyot C, Meier PJ, Roth J, Stieger B. ABC-transporters are localized in caveolin-1-positive and reggie-1-negative and reggie-2-negative microdomains of the canalicular membrane in rat hepatocytes. Hepatology 2009; 49:1673-82. [PMID: 19197976 DOI: 10.1002/hep.22807] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
UNLABELLED The canalicular plasma membrane is constantly exposed to bile acids acting as detergents. Bile acids are essential to mediate release of biliary lipids from the canalicular membrane. Membrane microdomains (previously called lipid rafts) are biochemically defined by their resistance to detergent solubilization at cold temperature. We aimed to investigate the canalicular plasma membrane for the presence of microdomains, which could protect this membrane against the detergent action of bile acids. Highly purified rat liver canalicular plasma membrane vesicles were extracted with 1% Triton X-100 or 1% Lubrol WX at 4 degrees C and subjected to flotation through sucrose step gradients. Both detergents yielded detergent-resistant membranes containing the microdomain markers alkaline phosphatase and sphingomyelin. However, cholesterol was resistant to Lubrol WX solubilization, whereas it was only marginally resistant to solubilization by Triton X-100. The microdomain marker caveolin-1 was localized to the canalicular plasma membrane domain and was resistant to Lubrol WX, but to a large extent solubilized by Triton X-100. The two additional microdomain markers, reggie-1 and reggie-2, were localized to the basolateral and canalicular plasma membrane and were partially resistant to Lubrol WX but resistant to Triton X-100. The canalicular transporters bile salt export pump, multidrug resistance protein 2, multidrug resistance-associated protein 2, and Abcg5 were largely resistant to Lubrol WX but were solubilized by Triton X-100. CONCLUSION These results indicate the presence of two different types of microdomains in the canalicular plasma membrane: "Lubrol-microdomains" and "Triton-microdomains". "Lubrol-microdomains" contain the machinery for canalicular bile formation and may be the starting place for canalicular lipid secretion.
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Affiliation(s)
- Manfred G Ismair
- Division of Clinical Pharmacology and Toxicology, Department of Medicine, University Hospital, Zurich, Switzerland
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43
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Nojiri S, Nakao H, Sugauchi F, Miyaki T, Senda K, Sasaki M, Kataoka H, Kamiya T, Nakazawa T, Ohara H, Orito E, Joh T. Effect of ursodeoxycholic acid on serum liver enzymes and bile acid metabolism in chronic active hepatitis C virus infection. Hepatol Res 2009; 39:21-30. [PMID: 18721155 DOI: 10.1111/j.1872-034x.2008.00406.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AIM Many reports have revealed ursodeoxycholic acid (UDCA) to be effective against chronic hepatitis C virus (HCV). However, some cases resist this therapy and the mechanism of action remains unclear. In this study, UDCA was administered to patients with chronic HCV and the correlation between the bile acids of the biliary bile and serum and the drug efficacy was investigated. METHODS Fifteen patients were given 600 mg/day of UDCA for more than 24 weeks. The serum bile acid concentrations and biliary and serum bile acid were collected before and after 24 weeks of UDCA treatment, and composition determined by high-performance liquid chromatography. RESULTS The treatment was effective in nine cases (ALT decreased to less than twice the normal values 80 IU/L) and ineffective in six cases. There was no significant difference in the serum bile acid concentrations before and after UDCA treatment between the values of both cases. After UDCA treatment, the serum percentage of UDCA (effective, 62.5 +/- 2.0; ineffective, 53.5 +/- 2.5, (P = 0.02)) and the percentage of chenodeoxycholic acid (CDCA) showed no remarkable changes. In the biliary bile the percentage of CDCA (effective, 30.9 +/- 2.0; ineffective, 20.0 +/- 3.0, (P = 0.007)) and the percentage of UDCA showed no remarkable changes. CONCLUSION In the effective cases, the percentage of UDCA in the serum and the percentage of CDCA in biliary bile were significantly higher than in the ineffective cases. This indicates that, when effective, CDCA decreases in hepatocytes and this reduction contributes to hepatoprotection.
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Affiliation(s)
- Shunsuke Nojiri
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Roma MG, Crocenzi FA, Mottino AD. Dynamic localization of hepatocellular transporters in health and disease. World J Gastroenterol 2008; 14:6786-801. [PMID: 19058304 PMCID: PMC2773873 DOI: 10.3748/wjg.14.6786] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [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
Vesicle-based trafficking of hepatocellular transporters involves delivery of the newly-synthesized carriers from the rough endoplasmic reticulum to either the plasma membrane domain or to an endosomal, submembrane compartment, followed by exocytic targeting to the plasma membrane. Once delivered to the plasma membrane, the transporters usually undergo recycling between the plasma membrane and the endosomal compartment, which usually serves as a reservoir of pre-existing transporters available on demand. The balance between exocytic targeting and endocytic internalization from/to this recycling compartment is therefore a chief determinant of the overall capability of the liver epithelium to secrete bile and to detoxify endo and xenobiotics. Hence, it is a highly regulated process. Impaired regulation of this balance may lead to abnormal localization of these transporters, which results in bile secretory failure due to endocytic internalization of key transporters involved in bile formation. This occurs in several experimental models of hepatocellular cholestasis, and in most human cholestatic liver diseases. This review describes the molecular bases involved in the biology of the dynamic localization of hepatocellular transporters and its regulation, with a focus on the involvement of signaling pathways in this process. Their alterations in different experimental models of cholestasis and in human cholestatic liver disease are reviewed. In addition, the causes explaining the pathological condition (e.g. disorganization of actin or actin-transporter linkers) and the mediators involved (e.g. activation of cholestatic signaling transduction pathways) are also discussed. Finally, several experimental therapeutic approaches based upon the administration of compounds known to stimulate exocytic insertion of canalicular transporters (e.g. cAMP, tauroursodeoxycholate) are described.
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45
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Cholesterol but not association with detergent resistant membranes is necessary for the transport function of MRP2/ABCC2. FEBS Lett 2008; 582:4153-7. [PMID: 19038257 DOI: 10.1016/j.febslet.2008.11.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 11/11/2008] [Accepted: 11/11/2008] [Indexed: 11/20/2022]
Abstract
MRP2(/ABCC2) excretes amphiphilic organic anions into bile, and associates with detergent-resistant bile canalicular membrane domains (DRM). Here, we have evaluated sensitivities of MRP2 transport function and DRM association by titrating the cellular cholesterol content. We demonstrate that the role of cholesterol in the partitioning of MRP2 to DRM can be separated from the role of cholesterol in the function of MRP2, such that (i) cholesterol is not necessary for the polarized distribution of MRP2 at the canalicular membrane, (ii) partitioning into DRM is not required for MRP2 function, yet (iii) the presence of cholesterol is necessary for transport activity.
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46
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Cillo U, Burra P, Norberto L, D'Amico D. Bile duct stones and casts after liver transplantation: Different entities but similar prevention strategy? Liver Transpl 2008; 14:1400-3. [PMID: 18825732 DOI: 10.1002/lt.21628] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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47
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Denk GU, Hohenester S, Wimmer R, Böhland C, Rust C, Beuers U. Role of mitogen-activated protein kinases in tauroursodeoxycholic acid-induced bile formation in cholestatic rat liver. Hepatol Res 2008; 38:717-26. [PMID: 18328068 DOI: 10.1111/j.1872-034x.2008.00321.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
AIM Ursodeoxycholic acid exerts anticholestatic effects in various cholestatic disorders and experimental models of cholestasis. Its taurine conjugate (TUDCA) stimulates bile salt secretion in isolated perfused rat livers (IPRL) under physiological, non-cholestatic conditions, in part by mitogen-activated protein kinase (MAPK)-dependent mechanisms. The role of MAPK in the anticholestatic effect of TUDCA, however, is unclear. Therefore, we studied the role of MAPK in the anticholestatic effect of TUDCA in IPRL and isolated rat hepatocytes (IRH) in taurolithocholic acid (TLCA)-induced cholestasis. METHODS Bile flow, biliary levels of 2,4-dinitrophenyl-S-glutathione (GS-DNP) as a marker of hepatobiliary organic anion secretion and activity of lactate dehydrogenase (LDH) in hepatovenous effluate as a marker of hepatocellular damage in IPRL perfused with TUDCA and/or TLCA were determined in the presence or absence of MAPK inhibitors. In addition, phosphorylation of Erk 1/2 and p38(MAPK) induced by TUDCA and/or TLCA was studied by Western immunoblot in IPRL and IRH. RESULTS TUDCA-induced bile flow was impaired by the Erk 1/2 inhibitor PD98059 in normal livers (-28%), but not in livers made cholestatic by TLCA. GS-DNP secretion was unaffected by PD98059 under both conditions. TUDCA-induced bile formation and organic anion secretion both in the presence and absence of TLCA were unaffected by the p38(MAPK) inhibitor SB202190. Erk 1/2 phosphorylation in liver tissue was unchanged after bile salt exposure for 70 min, but was transiently enhanced by TUDCA in IRH. CONCLUSION MAPK do not mediate the anticholestatic effects of TUDCA in TLCA-induced cholestasis.
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Affiliation(s)
- Gerald Ulrich Denk
- Department of Medicine II-Grosshadern, Klinikum of the University of Munich, Munich, Germany
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48
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Zinchuk V, Zinchuk O. Quantitative Colocalization Analysis of Confocal Fluorescence Microscopy Images. ACTA ACUST UNITED AC 2008; Chapter 4:Unit 4.19. [DOI: 10.1002/0471143030.cb0419s39] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Vadim Zinchuk
- Department of Anatomy and Cell Biology, Kochi University, Faculty of Medicine Japan
| | - Olga Zinchuk
- Institute of Anatomy, University of Berne, CH‐3000 Berne Switzerland
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49
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Hepatocellular transport in acquired cholestasis: new insights into functional, regulatory and therapeutic aspects. Clin Sci (Lond) 2008; 114:567-88. [PMID: 18377365 DOI: 10.1042/cs20070227] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The recent overwhelming advances in molecular and cell biology have added enormously to our understanding of the physiological processes involved in bile formation and, by extension, to our comprehension of the consequences of their alteration in cholestatic hepatopathies. The present review addresses in detail this new information by summarizing a number of recent experimental findings on the structural, functional and regulatory aspects of hepatocellular transporter function in acquired cholestasis. This comprises (i) a short overview of the physiological mechanisms of bile secretion, including the nature of the transporters involved and their role in bile formation; (ii) the changes induced by nuclear receptors and hepatocyte-enriched transcription factors in the constitutive expression of hepatocellular transporters in cholestasis, either explaining the primary biliary failure or resulting from a secondary adaptive response; (iii) the post-transcriptional changes in transporter function and localization in cholestasis, including a description of the subcellular structures putatively engaged in the endocytic internalization of canalicular transporters and the involvement of signalling cascades in this effect; and (iv) a discussion on how this new information has contributed to the understanding of the mechanism by which anticholestatic agents exert their beneficial effects, or the manner in which it has helped the design of new successful therapeutic approaches to cholestatic liver diseases.
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50
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Marin JJG, Macias RIR, Briz O, Perez MJ, Blazquez AG, Arrese M, Serrano MA. Molecular bases of the fetal liver-placenta-maternal liver excretory pathway for cholephilic compounds. Liver Int 2008; 28:435-54. [PMID: 18339071 DOI: 10.1111/j.1478-3231.2008.01680.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Potentially toxic endogenous compounds, such as bile acids (BAs) and biliary pigments, as well as many xenobiotics, such as drugs and food components, are biotransformed and eliminated by the hepatobiliary system with the collaboration of the kidney. However, the situation is very different during pregnancy because the fetal liver produces biliary compounds despite the fact that this organ, owing to its immaturity, is not able to eliminate them into bile. Moreover, the excretory ability of the fetal kidneys is also very limited. Thus, during the intra-uterine life, the major route to eliminate fetal BAs and biliary pigments is their transfer to the mother across the placenta. The maternal liver and, to a lesser extent, the maternal kidney, are then in charge of their biotransformation and elimination into faeces and urine respectively. This review describes current knowledge of the machinery responsible for the detoxification and excretion of cholephilic compounds through the pathway formed by the fetal liver-placenta-maternal liver trio.
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Affiliation(s)
- Jose J G Marin
- Laboratory of Experimental Hepatology and Drug Targeting (HEVEFARM), CIBERehd, University of Salamanca, Salamanca, Spain.
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