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Calamita G, Delporte C. Insights into the Function of Aquaporins in Gastrointestinal Fluid Absorption and Secretion in Health and Disease. Cells 2023; 12:2170. [PMID: 37681902 PMCID: PMC10486417 DOI: 10.3390/cells12172170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Aquaporins (AQPs), transmembrane proteins permeable to water, are involved in gastrointestinal secretion. The secretory products of the glands are delivered either to some organ cavities for exocrine glands or to the bloodstream for endocrine glands. The main secretory glands being part of the gastrointestinal system are salivary glands, gastric glands, duodenal Brunner's gland, liver, bile ducts, gallbladder, intestinal goblet cells, exocrine and endocrine pancreas. Due to their expression in gastrointestinal exocrine and endocrine glands, AQPs fulfill important roles in the secretion of various fluids involved in food handling. This review summarizes the contribution of AQPs in physiological and pathophysiological stages related to gastrointestinal secretion.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy;
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
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Yanda MK, Zeidan A, Cebotaru L. Ameliorating liver disease in an autosomal recessive polycystic kidney disease mouse model. Am J Physiol Gastrointest Liver Physiol 2023; 324:G404-G414. [PMID: 36880660 PMCID: PMC10085553 DOI: 10.1152/ajpgi.00255.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023]
Abstract
Systemic and portal hypertension, liver fibrosis, and hepatomegaly are manifestations associated with autosomal recessive polycystic kidney disease (ARPKD), which is caused by malfunctions of fibrocystin/polyductin (FPC). The goal is to understand how liver pathology occurs and to devise therapeutic strategies to treat it. We injected 5-day-old Pkhd1del3-4/del3-4 mice for 1 mo with the cystic fibrosis transmembrane conductance regulator (CFTR) modulator VX-809 designed to rescue processing and trafficking of CFTR folding mutants. We used immunostaining and immunofluorescence techniques to evaluate liver pathology. We assessed protein expression via Western blotting. We detected abnormal biliary ducts consistent with ductal plate abnormalities, as well as a greatly increased proliferation of cholangiocytes in the Pkhd1del3-4/del3-4 mice. CFTR was present in the apical membrane of cholangiocytes and increased in the Pkhd1del3-4/del3-4 mice, consistent with a role for apically located CFTR in enlarged bile ducts. Interestingly, we also found CFTR in the primary cilium, in association with polycystin (PC2). Localization of CFTR and PC2 and overall length of the cilia were increased in the Pkhd1del3-4/del3-4 mice. In addition, several of the heat shock proteins; 27, 70, and 90 were upregulated, suggesting that global changes in protein processing and trafficking had occurred. We found that a deficit of FPC leads to bile duct abnormalities, enhanced cholangiocyte proliferation, and misregulation of heat shock proteins, which all returned toward wild type (WT) values following VX-809 treatment. These data suggest that CFTR correctors can be useful as therapeutics for ARPKD. Given that these drugs are already approved for use in humans, they can be fast-tracked for clinical use.NEW & NOTEWORTHY ARPKD is a multiorgan genetic disorder resulting in newborn morbidity and mortality. There is a critical need for new therapies to treat this disease. We show that persistent cholangiocytes proliferation occurs in a mouse model of ARPKD along with mislocalized CFTR and misregulated heat shock proteins. We found that VX-809, a CFTR modulator, inhibits proliferation and limits bile duct malformation. The data provide a therapeutic pathway for strategies to treat ADPKD.
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Affiliation(s)
- Murali K Yanda
- Departments of Medicine and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Adi Zeidan
- Departments of Medicine and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liudmila Cebotaru
- Departments of Medicine and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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3
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Calamita G, Delporte C. Aquaporins in Glandular Secretion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:225-249. [PMID: 36717498 DOI: 10.1007/978-981-19-7415-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Exocrine and endocrine glands deliver their secretory product, respectively, at the surface of the target organs or within the bloodstream. The release of their products has been shown to rely on secretory mechanisms often involving aquaporins (AQPs). This chapter will provide insight into the role of AQPs in secretory glands located within the gastrointestinal tract, including salivary glands, gastric glands, duodenal Brunner's glands, liver, gallbladder, intestinal goblets cells, and pancreas, as well and in other parts of the body, including airway submucosal glands, lacrimal glands, mammary glands, and eccrine sweat glands. The involvement of AQPs in both physiological and pathophysiological conditions will also be highlighted.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari "Aldo Moro", Bari, Italy
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Carbonic anhydrase 14 protects the liver against the cytotoxicity of bile acids in a biliary bicarbonate umbrella-related manner. Life Sci 2022; 310:121117. [DOI: 10.1016/j.lfs.2022.121117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022]
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Norcia LF, Watanabe EM, Hamamoto Filho PT, Hasimoto CN, Pelafsky L, de Oliveira WK, Sassaki LY. Polycystic Liver Disease: Pathophysiology, Diagnosis and Treatment. Hepat Med 2022; 14:135-161. [PMID: 36200122 PMCID: PMC9528914 DOI: 10.2147/hmer.s377530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/07/2022] [Indexed: 11/25/2022] Open
Abstract
Polycystic liver disease (PLD) is a clinical condition characterized by the presence of more than 10 cysts in the liver. It is a rare disease Of genetic etiology that presents as an isolated disease or assoc\iated with polycystic kidney disease. Ductal plate malformation, ciliary dysfunction, and changes in cell signaling are the main factors involved in its pathogenesis. Most patients with PLD are asymptomatic, but in 2–5% of cases the disease has disabling symptoms and a significant reduction in quality of life. The diagnosis is based on family history of hepatic and/or renal polycystic disease, clinical manifestations, patient age, and polycystic liver phenotype shown on imaging examinations. PLD treatment has evolved considerably in the last decades. Somatostatin analogues hold promise in controlling disease progression, but liver transplantation remains a unique curative treatment modality.
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Affiliation(s)
- Luiz Fernando Norcia
- Department of Surgery, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
- Correspondence: Luiz Fernando Norcia, Department of Surgery, São Paulo State University (UNESP), Medical School, 783 Pedro Delmanto Street, Botucatu, São Paulo, 18610-303, Brazil, Tel +55 19982840542, Email
| | - Erika Mayumi Watanabe
- Department of Radiology, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
| | - Pedro Tadao Hamamoto Filho
- Department of Neurology, Psychology and Psychiatry, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
| | - Claudia Nishida Hasimoto
- Department of Surgery, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
| | - Leonardo Pelafsky
- Department of Surgery, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
| | - Walmar Kerche de Oliveira
- Department of Surgery, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
| | - Ligia Yukie Sassaki
- Department of Internal Medicine, São Paulo State University (Unesp), Medical School, Botucatu, São Paulo, Brazil
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Herta T, Kersten R, Chang JC, Hubers L, Go S, Tolenaars D, Paulusma CC, Nathanson MH, Elferink RO, van de Graaf SFJ, Beuers U. Role of the IgG4-related cholangitis autoantigen annexin A11 in cholangiocyte protection. J Hepatol 2022; 76:319-331. [PMID: 34718050 PMCID: PMC10804347 DOI: 10.1016/j.jhep.2021.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 09/20/2021] [Accepted: 10/11/2021] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Annexin A11 was identified as autoantigen in IgG4-related cholangitis (IRC), a B-cell driven disease. Annexin A11 modulates calcium-dependent exocytosis, a crucial mechanism for insertion of proteins into their target membranes. Human cholangiocytes form an apical 'biliary bicarbonate umbrella' regarded as defense against harmful hydrophobic bile acid influx. The bicarbonate secretory machinery comprises the chloride/bicarbonate exchanger AE2 and the chloride channel ANO1. We aimed to investigate the expression and function of annexin A11 in human cholangiocytes and a potential role of IgG1/IgG4-mediated autoreactivity against annexin A11 in the pathogenesis of IRC. METHODS Expression of annexin A11 in human liver was studied by immunohistochemistry and immunofluorescence. In human control and ANXA11 knockdown H69 cholangiocytes, intracellular pH, AE2 and ANO1 surface expression, and bile acid influx were examined using ratio microspectrofluorometry, cell surface biotinylation, and 22,23-3H-glycochenodeoxycholic acid permeation, respectively. The localization of annexin A11-mEmerald and ANO1-mCherry was investigated by live-cell microscopy in H69 cholangiocytes after incubation with IRC patient serum containing anti-annexin A11 IgG1/IgG4-autoantibodies or disease control serum. RESULTS Annexin A11 was strongly expressed in human cholangiocytes, but not hepatocytes. Knockdown of ANXA11 led to reduced plasma membrane expression of ANO1, but not AE2, alkalization of intracellular pH and uncontrolled bile acid influx. High intracellular calcium conditions led to annexin A11 membrane shift and colocalization with ANO1. Incubation with IRC patient serum inhibited annexin A11 membrane shift and reduced ANO1 surface expression. CONCLUSION Cholangiocellular annexin A11 mediates apical membrane abundance of the chloride channel ANO1, thereby supporting biliary bicarbonate secretion. Insertion is inhibited by IRC patient serum containing anti-annexin A11 IgG1/IgG4-autoantibodies. Anti-annexin A11 autoantibodies may contribute to the pathogenesis of IRC by weakening the 'biliary bicarbonate umbrella'. LAY SUMMARY We previously identified annexin A11 as a specific autoantigen in immunoglobulin G4-related cholangitis (IRC), a B-cell driven disease affecting the bile ducts. Human cholangiocytes are protected against harmful hydrophobic bile acid influx by a defense mechanism referred to as the 'biliary bicarbonate umbrella'. We found that annexin A11 is required for the formation of a robust bicarbonate umbrella. Binding of patient-derived annexin A11 autoantibodies inhibits annexin A11 function, possibly contributing to bile duct damage by weakening the biliary bicarbonate umbrella in patients with IRC.
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Affiliation(s)
- Toni Herta
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Remco Kersten
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands; Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, USA
| | - Jung-Chin Chang
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Lowiek Hubers
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Simei Go
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Dagmar Tolenaars
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Coen C Paulusma
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Michael H Nathanson
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, USA
| | - Ronald Oude Elferink
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Stan F J van de Graaf
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands
| | - Ulrich Beuers
- Department of Gastroenterology and Hepatology and Tytgat Institute for Liver and Intestinal Research, AGEM, Amsterdam University Medical Centers, location AMC, Amsterdam, The Netherlands.
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Abstract
PURPOSE OF REVIEW Primary biliary cholangitis (PBC) is characterized by autoimmune damage of intrahepatic bile ducts associated with a loss of tolerance to mitochondrial antigens. PBC etiopathogenesis is intriguing because of different perplexing features, namely: a) although mitochondria are present in all cell types and tissues, the damage is mainly restricted to biliary epithelial cells (BECs); b) despite being an autoimmune disorder, it does not respond to immunosuppressive drugs but rather to ursodeoxycholic acid, a bile salt that induces HCO3- rich choleresis; c) the overwhelming female preponderance of the disease remains unexplained. Here we present an etiopathogenic view of PBC which sheds light on these puzzling facts of the disease. RECENT FINDINGS PBC develops in patients with genetic predisposition to autoimmunity in whom epigenetic mechanisms silence the Cl-/HCO3- exchanger AE2 in both cholangiocytes and lymphoid cells. Defective AE2 function can produce BECs damage as a result of decreased biliary HCO3- secretion with disruption of the protective alkaline umbrella that normally prevents the penetration of toxic apolar bile salts into cholangiocytes. AE2 dysfunction also causes increased intracellular pH (pHi) in cholangiocytes, leading to the activation of soluble adenylyl cyclase, which sensitizes BECs to bile salt-induced apoptosis. Recently, mitophagy was found to be inhibited by cytosolic alkalization and stimulated by acidification. Accordingly, we propose that AE2 deficiency may disturb mitophagy in BECs, thus, promoting the accumulation of defective mitochondria, oxidative stress and presentation of mitochondrial antigens to the immune cells. As women possess a more acidic endolysosomal milieu than men, mitophagy might be more affected in women in an AE2-defective background. Apart from affecting BECs function, AE2 downregulation in lymphocytes may also contribute to alter immunoregulation facilitating autoreactive T-cell responses. SUMMARY PBC can be considered as a disorder of Cl-/HCO3- exchange in individuals with genetic predisposition to autoimmunity.
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Affiliation(s)
- Jesús Prieto
- Center for Applied Medical Research (Centro de Investigación Médica Aplicada, CIMA), University of Navarra, Pamplona
| | - Jesus M. Banales
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute – Donostia University Hospital – University of the Basque Country (UPV/EHU), San Sebastian
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, ‘Instituto de Salud Carlos III’)
- IKERBASQUE, Basque Foundation for Science, Bilbao
| | - Juan F. Medina
- Unit of Medical Training, School of Medicine, University of Navarra, Pamplona, Spain
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Sussman CR, Wang X, Chebib FT, Torres VE. Modulation of polycystic kidney disease by G-protein coupled receptors and cyclic AMP signaling. Cell Signal 2020; 72:109649. [PMID: 32335259 DOI: 10.1016/j.cellsig.2020.109649] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022]
Abstract
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disorder associated with polycystic liver disease (PLD) and other extrarenal manifestations, the most common monogenic cause of end-stage kidney disease, and a major burden for public health. Many studies have shown that alterations in G-protein and cAMP signaling play a central role in its pathogenesis. As for many other diseases (35% of all approved drugs target G-protein coupled receptors (GPCRs) or proteins functioning upstream or downstream from GPCRs), treatments targeting GPCR have shown effectiveness in slowing the rate of progression of ADPKD. Tolvaptan, a vasopressin V2 receptor antagonist is the first drug approved by regulatory agencies to treat rapidly progressive ADPKD. Long-acting somatostatin analogs have also been effective in slowing the rates of growth of polycystic kidneys and liver. Although no treatment has so far been able to prevent the development or stop the progression of the disease, these encouraging advances point to G-protein and cAMP signaling as a promising avenue of investigation that may lead to more effective and safe treatments. This will require a better understanding of the relevant GPCRs, G-proteins, cAMP effectors, and of the enzymes and A-kinase anchoring proteins controlling the compartmentalization of cAMP signaling. The purpose of this review is to provide an overview of general GPCR signaling; the function of polycystin-1 (PC1) as a putative atypical adhesion GPCR (aGPCR); the roles of PC1, polycystin-2 (PC2) and the PC1-PC2 complex in the regulation of calcium and cAMP signaling; the cross-talk of calcium and cAMP signaling in PKD; and GPCRs, adenylyl cyclases, cyclic nucleotide phosphodiesterases, and protein kinase A as therapeutic targets in ADPKD.
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Affiliation(s)
- Caroline R Sussman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Xiaofang Wang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Fouad T Chebib
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Vicente E Torres
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America.
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Sato A, Kakinuma S, Miyoshi M, Kamiya A, Tsunoda T, Kaneko S, Tsuchiya J, Shimizu T, Takeichi E, Nitta S, Kawai-Kitahata F, Murakawa M, Itsui Y, Nakagawa M, Azuma S, Koshikawa N, Seiki M, Nakauchi H, Asahina Y, Watanabe M. Vasoactive Intestinal Peptide Derived From Liver Mesenchymal Cells Mediates Tight Junction Assembly in Mouse Intrahepatic Bile Ducts. Hepatol Commun 2019; 4:235-254. [PMID: 32025608 PMCID: PMC6996346 DOI: 10.1002/hep4.1459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/23/2019] [Indexed: 01/20/2023] Open
Abstract
Formation of intrahepatic bile ducts (IHBDs) proceeds in accordance with their microenvironment. Particularly, mesenchymal cells around portal veins regulate the differentiation and ductular morphogenesis of cholangiocytes in the developing liver; however, further studies are needed to fully understand the arrangement of IHBDs into a continuous hierarchical network. This study aims to clarify the interaction between biliary and liver mesenchymal cells during IHBD formation. To identify candidate factors contributing to this cell–cell interaction, mesenchymal cells were isolated from embryonic day 16.5 matrix metalloproteinase 14 (MMP14)‐deficient (knockout [KO]) mice livers, in which IHBD formation is retarded, and compared with those of the wild type (WT). WT mesenchymal cells significantly facilitated the formation of luminal structures comprised of hepatoblast‐derived cholangiocytes (cholangiocytic cysts), whereas MMP14‐KO mesenchymal cells failed to promote cyst formation. Comprehensive analysis revealed that expression of vasoactive intestinal peptide (VIP) was significantly suppressed in MMP14‐KO mesenchymal cells. VIP and VIP receptor 1 (VIPR1) were mainly expressed in periportal mesenchymal cells and cholangiocytic progenitors during IHBD development, respectively, in vivo. VIP/VIPR1 signaling significantly encouraged cholangiocytic cyst formation and up‐regulated tight junction protein 1, cystic fibrosis transmembrane conductance regulator, and aquaporin 1, in vitro. VIP antagonist significantly suppressed the tight junction assembly and the up‐regulation of ion/water transporters during IHBD development in vivo. In a cholestatic injury model of adult mice, exogenous VIP administration promoted the restoration of damaged tight junctions in bile ducts and improved hyperbilirubinemia. Conclusion: VIP is produced by periportal mesenchymal cells during the perinatal stage. It supports bile duct development by establishing tight junctions and up‐regulating ion/water transporters in cholangiocytes. VIP contributes to prompt recovery from cholestatic damage through the establishment of tight junctions in the bile ducts.
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Affiliation(s)
- Ayako Sato
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Sei Kakinuma
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan.,Department of Liver Disease Control Tokyo Medical and Dental University (TMDU) Tokyo Japan
| | - Masato Miyoshi
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Akihide Kamiya
- Department of Molecular Life Sciences School of Medicine Tokai University Isehara Japan
| | - Tomoyuki Tsunoda
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Shun Kaneko
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Jun Tsuchiya
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Taro Shimizu
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Eiko Takeichi
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Sayuri Nitta
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Fukiko Kawai-Kitahata
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Miyako Murakawa
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Yasuhiro Itsui
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Mina Nakagawa
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Seishin Azuma
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan
| | - Naohiko Koshikawa
- Division of Cancer Cell Research Institute of Medical Science University of Tokyo Tokyo Japan
| | - Motoharu Seiki
- Division of Cancer Cell Research Institute of Medical Science University of Tokyo Tokyo Japan
| | - Hiromitsu Nakauchi
- Institute for Stem Cell Biology and Regenerative Medicine Stanford University School of Medicine Stanford CA.,Division of Stem Cell Therapy Institute of Medical Science University of Tokyo Tokyo Japan
| | - Yasuhiro Asahina
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan.,Department of Liver Disease Control Tokyo Medical and Dental University (TMDU) Tokyo Japan
| | - Mamoru Watanabe
- Department of Gastroenterology and Hepatology Tokyo Medical and Dental University Tokyo Japan.,Advanced Research Institute Tokyo Medical and Dental University (TMDU) Tokyo Japan
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Stremmel W, Staffer S, Weiskirchen R. Phosphatidylcholine Passes by Paracellular Transport to the Apical Side of the Polarized Biliary Tumor Cell Line Mz-ChA-1. Int J Mol Sci 2019; 20:ijms20164034. [PMID: 31430850 PMCID: PMC6720464 DOI: 10.3390/ijms20164034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 01/09/2023] Open
Abstract
Phosphatidylcholine (PC) translocation into mucus of the intestine was shown to occur via a paracellular transport across the apical/lateral tight junction (TJ) barrier. In case this could also be operative in biliary epithelial cells, this may have implication for the pathogenesis of primary sclerosing cholangitis (PSC). We here evaluated the transport of PC across polarized cholangiocytes. Therefore, the biliary tumor cell line Mz-ChA-1 was grown to confluency. In transwell culture systems the translocation of PC to the apical compartment was analyzed. After 21 days in culture, polarized Mz-ChA-1 cells revealed a predominant apical translocation of choline containing phospholipids including PC with minimal intracellular accumulation. Transport was suppressed by TJ destruction employing chemical inhibitors and pretreatment with siRNA to TJ forming proteins as well as the apical transmembrane mucin 3 as PC acceptor. Apical translocation was dependent on a negative apical electrical potential created by the cystic fibrosis transmembrane conductance regulator (CFTR) and the anion exchange protein 2 (AE2). It was stimulated by apical application of secretory mucins. The results indicated the existence of a paracellular PC passage across apical/lateral TJ of the polarized biliary epithelial tumor cell line Mz-ChA-1. This has implication for the generation of a protective mucus barrier in the biliary tree.
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Affiliation(s)
- Wolfgang Stremmel
- Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Germany.
| | - Simone Staffer
- University Clinics of Heidelberg, D-69120 Heidelberg, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, D-52074 Aachen, Germany
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11
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Abstract
Cholangiocytes, the epithelial cells lining the intrahepatic and extrahepatic bile ducts, are highly specialized cells residing in a complex anatomic niche where they participate in bile production and homeostasis. Cholangiocytes are damaged in a variety of human diseases termed cholangiopathies, often causing advanced liver failure. The regulation of cholangiocyte transport properties is increasingly understood, as is their anatomical and functional heterogeneity along the biliary tract. Furthermore, cholangiocytes are pivotal in liver regeneration, especially when hepatocyte regeneration is compromised. The role of cholangiocytes in innate and adaptive immune responses, a critical subject relevant to immune-mediated cholangiopathies, is also emerging. Finally, reactive ductular cells are present in many cholestatic and other liver diseases. In chronic disease states, this repair response contributes to liver inflammation, fibrosis and carcinogenesis and is a subject of intense investigation. This Review highlights advances in cholangiocyte research, especially their role in development and liver regeneration, their functional and biochemical heterogeneity, their activation and involvement in inflammation and fibrosis and their engagement with the immune system. We aim to focus further attention on cholangiocyte pathobiology and the search for new disease-modifying therapies targeting the cholangiopathies.
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Bile Acid-Activated Receptors: GPBAR1 (TGR5) and Other G Protein-Coupled Receptors. Handb Exp Pharmacol 2019; 256:19-49. [PMID: 31302759 DOI: 10.1007/164_2019_230] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The BA-responsive GPCRs S1PR2 and TGR5 are almost ubiquitously expressed in human and rodent tissues. In the liver, S1PR2 is expressed in all cell types, while TGR5 is predominately found in non-parenchymal cells. In contrast to S1PR2, which is mainly activated by conjugated bile acids (BAs), all BAs serve as ligands for TGR5 irrespective of their conjugation state and substitution pattern.Mice with targeted deletion of either S1PR2 or TGR5 are viable and develop no overt phenotype. In liver injury models, S1PR2 exerts pro-inflammatory and pro-fibrotic effects and thus aggravates liver damage, while TGR5 mediates anti-inflammatory, anti-cholestatic, and anti-fibrotic effects. Thus, inhibitors of S1PR2 signaling and agonists for TGR5 have been employed to attenuate liver injury in rodent models for cholestasis, nonalcoholic steatohepatitis, and fibrosis/cirrhosis.In biliary epithelial cells, both receptors activate a similar signaling cascade resulting in ERK1/2 phosphorylation and cell proliferation. Overexpression of both S1PR2 and TGR5 was found in human cholangiocarcinoma tissue as well as in CCA cell lines, where stimulation of both GPCRs resulted in transactivation of the epidermal growth factor receptor and triggered cell proliferation as well as increased cell migration and invasiveness.This chapter will focus on the function of S1PR2 and TGR5 in different liver cell types and summarizes current knowledge on the role of these receptors in liver disease models.
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Rodrigues PM, Perugorria MJ, Santos-Laso A, Bujanda L, Beuers U, Banales JM. Primary biliary cholangitis: A tale of epigenetically-induced secretory failure? J Hepatol 2018; 69:1371-1383. [PMID: 30193962 DOI: 10.1016/j.jhep.2018.08.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/14/2018] [Accepted: 08/24/2018] [Indexed: 12/16/2022]
Abstract
Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease associated with autoimmune-related destruction of small to medium size intrahepatic bile ducts. The aetiology of PBC is unknown and its pathogenesis remains obscure. Both genetic variants and environmental factors have been linked to increased PBC susceptibility, with other alterations known to cooperate in disease pathobiology. Increasing evidence indicates the presence of epigenetic abnormalities in PBC, particularly alterations of cholangiocellular microRNAs (miRNAs or miRs). This review highlights and discusses the most relevant epigenetic alterations found in patients with PBC, focusing on the role of miR-506 in the promotion of cholestasis and immune activation.
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Affiliation(s)
- Pedro M Rodrigues
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute - Donostia University Hospital, University of the Basque Country (UPV/EHU), San Sebastian, Spain
| | - Maria J Perugorria
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute - Donostia University Hospital, University of the Basque Country (UPV/EHU), San Sebastian, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, "Instituto de Salud Carlos III"), Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Alvaro Santos-Laso
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute - Donostia University Hospital, University of the Basque Country (UPV/EHU), San Sebastian, Spain
| | - Luis Bujanda
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute - Donostia University Hospital, University of the Basque Country (UPV/EHU), San Sebastian, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, "Instituto de Salud Carlos III"), Spain
| | - Ulrich Beuers
- Tytgat Institute for Liver and Intestinal Research and Department of Gastroenterology & Hepatology, Amsterdam Gastroenterology and Metabolism, AMC, Amsterdam, The Netherlands
| | - Jesus M Banales
- Department of Liver and Gastrointestinal Diseases, Biodonostia Health Research Institute - Donostia University Hospital, University of the Basque Country (UPV/EHU), San Sebastian, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, "Instituto de Salud Carlos III"), Spain; Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
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14
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van Niekerk J, Kersten R, Beuers U. Role of Bile Acids and the Biliary HCO 3- Umbrella in the Pathogenesis of Primary Biliary Cholangitis. Clin Liver Dis 2018; 22:457-479. [PMID: 30259847 DOI: 10.1016/j.cld.2018.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The biliary HCO3- umbrella hypothesis states that human cholangiocytes and hepatocytes create a protective apical alkaline barrier against millimolar concentrations of potentially toxic glycine-conjugated bile salts in bile by secreting HCO3- into the bile duct lumen. This alkaline barrier may retain biliary bile salts in their polar, deprotonated, and membrane-impermeant state to avoid uncontrolled invasion of apolar toxic bile acids, which initiate apoptosis, autophagy and senescence. In primary biliary cholangitis, defects of the biliary HCO3- umbrella, leading to impaired biliary HCO3- secretion have been identified. Current medical therapies stabilize the putatively defective biliary HCO3- umbrella and improve long-term prognosis.
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Affiliation(s)
- Jorrit van Niekerk
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Remco Kersten
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Ulrich Beuers
- Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands.
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15
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Gookin JL, Mathews KG, Cullen J, Seiler G. Qualitative metabolomics profiling of serum and bile from dogs with gallbladder mucocele formation. PLoS One 2018; 13:e0191076. [PMID: 29324798 PMCID: PMC5764353 DOI: 10.1371/journal.pone.0191076] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 12/26/2017] [Indexed: 01/20/2023] Open
Abstract
Mucocele formation is characterized by secretion of abnormally thick mucus by the gallbladder epithelium of dogs that may cause obstruction of the bile duct or rupture of the gallbladder. The disease is increasingly recognized and is associated with a high morbidity and mortality. The cause of gallbladder mucocele formation in dogs is unknown. There is a strong breed predisposition and affected dogs have a high incidence of concurrent endocrinopathy or hyperlipidemia. These observations suggest a significant influence of both genetic and metabolic factors on disease pathogenesis. In this study, we investigated a theory that mucocele formation is associated with a syndrome of metabolic disruption. We surmised that a global, untargeted metabolomics approach could provide unique insight into the systemic pathogenesis of gallbladder mucocele formation and identify specific compounds as candidate biomarkers or treatment targets. Moreover, concurrent examination of the serum and hepatic duct bile metabolome would enable the construction of mechanism-based theories or identification of specific compounds responsible for altered function of the gallbladder epithelium. Abnormalities observed in dogs with gallbladder mucocele formation, including a 33-fold decrease in serum adenosine 5’-monophosphate (AMP), lower quantities of precursors required for synthesis of energy transporting nucleotides, and increases in citric acid cycle intermediates, suggest excess metabolic energy and a carbon surplus. Altered quantities of compounds involved in protein translation and RNA turnover, together with accumulation of gamma-glutamylated and N-acetylated amino acids in serum suggest abnormal regulation of protein and amino acid metabolism. Increases in lathosterol and 7α-hydroxycholesterol suggest a primary increase in cholesterol synthesis and diversion to bile acid formation. A number of specific biomarker compounds were identified for their ability to distinguish between control dogs and those that formed a gallbladder mucocele. Particularly noteworthy was a significant decrease in quantity of biologically active compounds that stimulate biliary ductal fluid secretion including adenosine, cAMP, taurolithocholic acid, and taurocholic acid. These findings support the presence of significant metabolic disruption in dogs with mucocele formation. A targeted, quantitative analysis of the identified serum biomarkers is warranted to determine their utility for diagnosis of this disease. Finally, repletion of compounds whose biological activity normally promotes biliary ductal secretion should be examined for any therapeutic impact for resolution or prevention of mucocele formation.
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Affiliation(s)
- Jody L Gookin
- Department of Clinical Sciences, College of Veterinary Medicine and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Kyle G Mathews
- Department of Clinical Sciences, College of Veterinary Medicine and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
| | - John Cullen
- Department of Population Health and Pathobiology, College of Veterinary Medicine and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Gabriela Seiler
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine and Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, United States of America
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16
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Abstract
Aquaporins (AQPs ) are expressed in most exocrine and endocrine secretory glands. Consequently, summarizing the expression and functions of AQPs in secretory glands represents a daunting task considering the important number of glands present in the body, as well as the number of mammalian AQPs - thirteen. The roles played by AQPs in secretory processes have been investigated in many secretory glands. However, despite considerable research, additional studies are clearly needed to pursue our understanding of the role played by AQPs in secretory processes. This book chapter will focus on summarizing the current knowledge on AQPs expression and function in the gastrointestinal tract , including salivary glands, gastric glands, Duodenal Brunner's gland, liver and gallbladder, intestinal goblets cells, exocrine and endocrine pancreas, as well as few other secretory glands including airway submucosal glands, lacrimal glands, mammary glands and eccrine sweat glands.
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Affiliation(s)
- Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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17
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Kawaguchi K, Yoshida S, Hatano R, Asano S. Pathophysiological Roles of Ezrin/Radixin/Moesin Proteins. Biol Pharm Bull 2017; 40:381-390. [PMID: 28381792 DOI: 10.1248/bpb.b16-01011] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ezrin/radixin/moesin (ERM) proteins function as general cross-linkers between plasma membrane proteins and the actin cytoskeleton and are involved in the functional expression of membrane proteins on the cell surface. They also integrate Rho guanosine 5'-triphosphatase (GTPase) signaling to regulate cytoskeletal organization by sequestering Rho-related proteins. They act as protein kinase A (PKA)-anchoring proteins and sequester PKA close to its target proteins for their effective phosphorylation and functional regulation. Therefore, ERM proteins seem to play important roles in the membrane transport of electrolytes by ion channels and transporters. In this review, we focus on the pathophysiological roles of ERM proteins in in vivo studies and introduce the phenotypes of their knockout and knockdown mice.
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Affiliation(s)
- Kotoku Kawaguchi
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University
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18
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Bile acids and their receptors during liver regeneration: "Dangerous protectors". Mol Aspects Med 2017; 56:25-33. [PMID: 28302491 DOI: 10.1016/j.mam.2017.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/07/2017] [Accepted: 03/10/2017] [Indexed: 02/07/2023]
Abstract
Tissue repair is orchestrated by a finely tuned interplay between processes of regeneration, inflammation and cell protection, allowing organisms to restore their integrity after partial loss of cells or organs. An important, although largely unexplored feature is that after injury and during liver repair, liver functions have to be maintained to fulfill the peripheral demand. This is particularly critical for bile secretion, which has to be finely modulated in order to preserve liver parenchyma from bile-induced injury. However, mechanisms allowing the liver to maintain biliary homeostasis during repair after injury are not completely understood. Besides cytokines and growth factors, bile acids (BA) and their receptors constitute an insufficiently explored signaling network during liver regeneration and repair. BA signal through both nuclear (mainly Farnesoid X Receptor, FXR) and membrane (mainly G Protein-coupled BA Receptor 1, GPBAR-1 or TGR5) receptors which distributions are large in the organism, and which activation elicits a wide array of biological responses. While a number of studies have been dedicated to FXR signaling in liver repair processes, TGR5 remains poorly explored in this context. Because of the massive and potentially harmful BA overload that faces the remnant liver after partial ablation or destruction, both BA-induced adaptive and proliferative responses may stand in a central position to contribute to the regenerative response. Based on the available literature, both BA receptors may act in synergy during the regeneration process, in order to protect the remnant liver and maintain biliary homeostasis, otherwise potentially toxic BA overload would result in parenchymal insult and compromise optimal restoration of a functional liver mass.
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19
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Ambe PC, Gödde D, Zirngibl H, Störkel S. Aquaporin-1 and 8 expression in the gallbladder mucosa might not be associated with the development of gallbladder stones in humans. Eur J Clin Invest 2016; 46:227-33. [PMID: 26707370 DOI: 10.1111/eci.12586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/21/2015] [Indexed: 12/15/2022]
Abstract
BACKGROUND Cholecystolithiasis is a highly prevalent condition in the Western world. Gallbladder stone-related conditions represent the second most common gastrointestinal pathology. Cholesterol stones represent over 80% of gallstones. Cholesterol stones develop secondary to crystallization of bile cholesterol. Water resorption from gallbladder bile via aquaporin in the gallbladder mucosa might play a role in the development of cholesterol stones. This study investigated the expression of Aquaporin-1 (AQP1) and Aquaporin-8 (AQP8) in the human gallbladder mucosa and their possible association with the formation of gallbladder stones. METHODS The expression of AQP1 and AQP8 in the gallbladder mucosa was examined via immunohistochemical staining. The expression of both AQP1 and AQP8 in the gallbladder mucosa of stone carriers (study group) was compared to that of nonstone carriers (control group). RESULTS Eighty-four gallbladder specimens from 44 male (52·2%) and 40 female (47·6%) patients were analysed. The study group included 47 specimens from stone carriers, while 37 specimens from stone-free gallbladders were included in the control group. Immunostaining for both AQP1 and AQP8 was positive in 80 cases. AQP1 was expressed both over the apical and intercellular membrane, while AQP8 was expressed only over the apical membrane. A similar distribution was recorded in specimens from the cystic duct. Immunostaining with AQP1 was generally stronger in comparison with AQP8. No significant (P > 0·05) relationship was found between aquaporin expression and the presence or absence of gallbladder stones. CONCLUSION AQP1 and AQP8 are both expressed in the gallbladder and cystic duct mucosa. However, their role in the development of gallbladder stones is still to be proven.
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Affiliation(s)
- Peter C Ambe
- Department of Surgery II, Helios Klinikum Wuppertal, Universität Witten Herdecke, Wuppertal, Germany
| | - Daniel Gödde
- Institute of Pathology and Molecular Pathology, Helios Klinikum Wuppertal, Universität Witten Herdecke, Wuppertal, Germany
| | - Hubert Zirngibl
- Department of Surgery II, Helios Klinikum Wuppertal, Universität Witten Herdecke, Wuppertal, Germany
| | - Stephan Störkel
- Institute of Pathology and Molecular Pathology, Helios Klinikum Wuppertal, Universität Witten Herdecke, Wuppertal, Germany
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20
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Huqi San-Evoked Rat Colonic Anion Secretion through Increasing CFTR Expression. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:301640. [PMID: 26290673 PMCID: PMC4531196 DOI: 10.1155/2015/301640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/06/2014] [Accepted: 10/12/2014] [Indexed: 02/07/2023]
Abstract
Huqi San (HQS) is a Chinese herbal preparation of eight medicinal herbs that promote diuresis, detoxification, blood circulation, and cholestasis. Defects in transporter expression and function can cause cholestasis and jaundice. However, the mechanism of the cholestasis underlying HQS effects, especially on the gastrointestinal tract ion secretion, has not been elucidated. Real-time RT-PCR and Western blotting were used to study the expression and localization of cystic fibrosis transmembrane conductance regulator (CFTR) and α-ENaC in rat alimentary tract, and then the effect of HQS on the ion transport in rat distal colon mucosa was investigated using the short-circuit current (ISC) technique. The results showed that pretreatment with HQS significantly enhanced mRNA transcripts and protein content of CFTR in liver and distal colon but not α-ENaC in alimentary organs. HQS increases ISC and decreases the transepithelial resistance. Pretreatment with epithelial Na+ channel blocker did not affect the ISC responses elicited by HQS, but removal of extracellular Cl− or pretreatment with Cl− channel or Na+-K+-2Cl− cotransporter blocker inhibited HQS-elicited ISC responses. These findings demonstrated that HQS, RA, and RP can stimulate Cl− secretion in the distal colon by increasing the mRNA transcripts and protein content of CFTR in liver and distal colon.
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21
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Gregoire F, Lucidi V, Zerrad-Saadi A, Virreira M, Bolaky N, Delforge V, Lemmers A, Donckier V, Devière J, Demetter P, Perret J, Delporte C. Analysis of aquaporin expression in liver with a focus on hepatocytes. Histochem Cell Biol 2015; 144:347-63. [PMID: 26126651 DOI: 10.1007/s00418-015-1341-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2015] [Indexed: 12/30/2022]
Abstract
A deeper understanding of aquaporins (AQPs) expression and transcriptional regulation will provide useful information for liver pathophysiology. We established a complete AQPs mRNA expression profile in human and mouse liver, as well as protein localization of expressed AQPs. Additionally, the modulation of AQPs mRNA levels in response to various agents was determined in human HuH7 cells and in primary culture of mouse hepatocytes. AQP1, AQP3, AQP7, AQP8, and AQP9 mRNA and protein expressions were detected in human liver, while only AQP6 and AQP11 mRNAs were detected. We reported for the first time the localization of AQP3 in Kupffer cells, AQP7 in hepatocytes and endothelial cells, and AQP9 in cholangiocytes. In addition, we confirmed the localization of AQP1 in endothelial cells, and of AQP8 and AQP9 in hepatocytes. On HuH7 cells, we reported the presence of AQP4 mRNA, confirmed the presence of AQP3, AQP7, and AQP11 mRNAs, but not of AQP8 mRNA. On primary culture of murine hepatocytes, AQP1 and AQP7 mRNAs were identified, while the presence of AQP3, AQP8, AQP9, and AQP11 mRNAs was confirmed. At the protein level, murine endothelial liver cells expressed AQP1 and AQP9, while hepatocytes expressed AQP3, AQP7, AQP8, and AQP9, and macrophages expressed AQP3. Dexamethasone, forskolin, AICAR, rosiglitazone, octanoylated, and non-octanoylated ghrelin regulated some AQP expression in primary culture of murine hepatocytes and human HuH7 cells. Additional studies will be required to further assess the role of AQPs expression in human and murine liver and understand the transcriptional regulation of AQPs in hepatocytes under pathophysiological conditions.
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Affiliation(s)
- Françoise Gregoire
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Valério Lucidi
- Digestive Oncology Department, Erasme Hospital, Brussels, Belgium
| | - Amal Zerrad-Saadi
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Myrna Virreira
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Nargis Bolaky
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Valérie Delforge
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Arnaud Lemmers
- Gastroenterology Department, Erasme Hospital, Brussels, Belgium
| | - Vincent Donckier
- Digestive Oncology Department, Erasme Hospital, Brussels, Belgium
| | - Jacques Devière
- Gastroenterology Department, Erasme Hospital, Brussels, Belgium
| | - Pieter Demetter
- Anatomopathology Department, Erasme Hospital, Brussels, Belgium
| | - Jason Perret
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Université Libre de Bruxelles, Brussels, Belgium.
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22
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Jourdainne V, Péan N, Doignon I, Humbert L, Rainteau D, Tordjmann T. The Bile Acid Receptor TGR5 and Liver Regeneration. Dig Dis 2015; 33:319-26. [PMID: 26045264 DOI: 10.1159/000371668] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Most of the literature on the bile acid (BA) membrane receptor TGR5 is dedicated to its potential role in the metabolic syndrome, through its regulatory impact on energy expenditure, insulin and GLP-1 secretion, and inflammatory processes. While the receptor was cloned in 2002, very little data are available on TGR5 functions in the normal and diseased liver. However, TGR5 is highly expressed in Kupffer cells and liver endothelial cells, and is particularly enriched in the biliary tract [cholangiocytes and gallbladder (GB) smooth muscle cells]. We recently demonstrated that TGR5 has a crucial protective impact on the liver in case of BA overload, including after partial hepatectomy. KEY MESSAGES TGR5-KO mice after PH exhibited periportal bile infarcts, excessive hepatic inflammation and defective adaptation of biliary composition (bicarbonate and chloride). Most importantly, TGR5-KO mice had a more hydrophobic BA pool, with more secondary BA than WT animals, suggesting that TGR5-KO bile may be harmful for the liver, mainly in situations of BA overload. As GB is both the tissue displaying the highest level of TGR5 expression and a crucial physiological site for the regulation of BA pool hydrophobicity by reducing secondary BA, we investigated whether TGR5 may control BA pool composition through an impact on GB. Preliminary data suggest that in the absence of TGR5, reduced GB filling dampens the cholecystohepatic shunt, resulting in more secondary BA, more hydrophobic BA pool and extensive liver injury in case of BA overload. CONCLUSIONS In the setting of BA overload, TGR5 is protective of the liver through the regulation of not only secretory and inflammatory processes, but also through the control of BA pool composition, at least in part by targeting the GB. Thereby, TGR5 appears to be crucial for protecting the regenerating liver from BA overload.
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23
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Fouassier L, Fiorotto R. Ezrin finds its groove in cholangiocytes. Hepatology 2015; 61:1467-70. [PMID: 25545157 PMCID: PMC4406785 DOI: 10.1002/hep.27675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 12/18/2014] [Indexed: 12/07/2022]
Affiliation(s)
- Laura Fouassier
- INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, F-75012, Paris, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, Centre de Recherche Saint-Antoine F-75012, Paris, France
| | - Romina Fiorotto
- Section of Digestive Diseases, Liver Center, Yale University School of Medicine, Cedar Street 333, New Haven, CT 06520, USA
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24
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Hatano R, Akiyama K, Tamura A, Hosogi S, Marunaka Y, Caplan MJ, Ueno Y, Tsukita S, Asano S. Knockdown of ezrin causes intrahepatic cholestasis by the dysregulation of bile fluidity in the bile duct epithelium in mice. Hepatology 2015; 61:1660-71. [PMID: 25311759 PMCID: PMC6083834 DOI: 10.1002/hep.27565] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 10/10/2014] [Indexed: 12/22/2022]
Abstract
UNLABELLED Cholangiopathies share common features, including bile duct proliferation, periportal fibrosis, and intrahepatic cholestasis. Damage of biliary epithelium by autoimunne disorder, virus infection, toxic compounds, and developmental abnormalities causes severe progressive hepatic disorders responsible for high mortality. However, the etiologies of these cholestatic diseases remain unclear because useful models to study the pathogenic mechanisms are not available. In the present study, we have found that ezrin knockdown (Vil2(kd/kd) ) mice develop severe intrahepatic cholestasis characterized by extensive bile duct proliferation, periductular fibrosis, and intrahepatic bile acid accumulation without developmental defects of bile duct morphology and infiltration of inflammatory cells. Ezrin is a membrane cytoskeletal cross-linker protein, which is known to interact with transporters, scaffold proteins, and actin cytoskeleton at the plasma membrane. We found that the normal apical membrane localizations of several transport proteins including cystic fibrosis transmembrane conductance regulator (CFTR), anion exchanger 2 (AE-2), aquaporin 1 (AQP1), and Na(+) /H(+) exchanger regulatory factor were disturbed in bile ducts of Vil2(kd/kd) mice. Stable expression of a dominant negative form of ezrin in immortalized mouse cholangiocytes also led to the reduction of the surface expression of CFTR, AE-2, and AQP1. Reduced surface expression of these transport proteins was accompanied by reduced functional expression, as evidenced by the fact these cells exhibited decreased CFTR-mediated Cl(-) efflux activity. Furthermore, bile flow and biliary HCO3 (-) concentration were also significantly reduced in Vil2(kd/kd) mice. CONCLUSION Dysfunction of ezrin mimics important aspects of the pathological mechanisms responsible for cholangiopathies. The Vil2(kd/kd) mouse may be a useful model to exploit in the development and testing of potential therapies for cholangiopathies.
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Affiliation(s)
- Ryo Hatano
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan
| | - Kaori Akiyama
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan
| | - Atsushi Tamura
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shigekuni Hosogi
- Department of Molecular Cell Physiology and Bio- Ionomics, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology and Bio- Ionomics, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Michael J. Caplan
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT
| | - Yoshiyuki Ueno
- Department of Gastroenterology, Yamagata University School of Medicine, Yamagata, Japan
| | - Sachiko Tsukita
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shinji Asano
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University, Shiga, Japan
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25
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Abstract
Polycystic liver diseases are genetic disorders characterized by progressive bile duct dilatation and/or cyst development. The large volume of hepatic cysts causes different symptoms and complications such as abdominal distension, local pressure with back pain, hypertension, gastro-oesophageal reflux and dyspnea as well as bleeding, infection and rupture of the cysts. Current therapeutic strategies are based on surgical procedures and pharmacological management, which partially prevent or ameliorate the disease. However, as these treatments only show short-term and/or modest beneficial effects, liver transplantation is the only definitive therapy. Therefore, interest in understanding the molecular mechanisms involved in disease pathogenesis is increasing so that new targets for therapy can be identified. In this Review, the genetic mechanisms underlying polycystic liver diseases and the most relevant molecular pathways of hepatic cystogenesis are discussed. Moreover, the main clinical and preclinical studies are highlighted and future directions in basic as well as clinical research are indicated.
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26
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Godoy V, Banales JM, Medina JF, Pastor-Anglada M. Functional crosstalk between the adenosine transporter CNT3 and purinergic receptors in the biliary epithelia. J Hepatol 2014; 61:1337-43. [PMID: 25034758 DOI: 10.1016/j.jhep.2014.06.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/17/2014] [Accepted: 06/27/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS Both hepatocytes and cholangiocytes release ATP into the bile, where it acts as a potent autocrine/paracrine stimulus that activates biliary secretory mechanisms. ATP is known to be metabolized into multiple breakdown products, ultimately yielding adenosine. However, the elements implicated in the adenosine-dependent purinergic regulation of cholangiocytes are not known. METHODS Normal rat cholangiocytes (NRCs) were used to study the expression of adenosine receptors and transporters and their functional interactions at the apical and basolateral membrane domains of polarized cholangiocytes. RESULTS We found that: (1) cholangiocytes exclusively express two concentrative nucleoside transporters (CNT) known to be efficient adenosine carriers: CNT3, located at the apical membrane, and CNT2, located at apical and basolateral membrane domains; (2) in both domains, NRCs also express the high affinity adenosine receptor A2A, which modulated the activity of apical CNT3 in a domain-specific manner; (3) the regulation exerted by A2A on CNT3 was dependent upon the cAMP/PKA/ERK/CREB axis, intracellular trafficking mechanisms and AMPK phosphorylation; (4) secretin increased the activity of the apically-located CNT3, and promoted additional basolateral CNT3-related activity; and (5) extracellular ATP (a precursor of adenosine) was able to exert an inhibitory effect on the apical activity of both CNT3 and CNT2. CONCLUSIONS This study uncovered the functional expression of nucleoside transporters in cholangiocytes and provides evidence for direct crosstalks between adenosine transporters and receptors for adenosine and its natural extracellular precursor, ATP. Our data anticipate the possibility of adenosine playing a major role in the physiopathology of the biliary epithelia.
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Affiliation(s)
- Valeria Godoy
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain
| | - Jesús M Banales
- Department of Liver Diseases, Biodonostia Research Institute (Donostia University Hospital), IKERBASQUE (Basque Foundation for Science), University of Basque Country (UPV/EHU), San Sebastian, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain
| | - Juan F Medina
- Molecular Genetics, Division of Gene Therapy and Hepatology, School of Medicine and CIMA of the University of Navarra, Pamplona, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain
| | - Marçal Pastor-Anglada
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain.
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Sabbatini ME, Gorelick F, Glaser S. Adenylyl cyclases in the digestive system. Cell Signal 2014; 26:1173-81. [PMID: 24521753 DOI: 10.1016/j.cellsig.2014.01.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 01/31/2014] [Indexed: 02/08/2023]
Abstract
Adenylyl cyclases (ACs) are a group of widely distributed enzymes whose functions are very diverse. There are nine known transmembrane AC isoforms activated by Gαs. Each has its own pattern of expression in the digestive system and differential regulation of function by Ca(2+) and other intracellular signals. In addition to the transmembrane isoforms, one AC is soluble and exhibits distinct regulation. In this review, the basic structure, regulation and physiological roles of ACs in the digestive system are discussed.
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Affiliation(s)
| | - Fred Gorelick
- Department of Cell Biology and Medicine, Yale University, United States; VA CT, United States
| | - Shannon Glaser
- Department of Internal Medicine, Scott & White-Digestive Disease Research Center, Texas A&M Health Science Center, Central Texas Veterans Health Care System, United States
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Concepcion AR, Lopez M, Ardura-Fabregat A, Medina JF. Role of AE2 for pHi regulation in biliary epithelial cells. Front Physiol 2014; 4:413. [PMID: 24478713 PMCID: PMC3894451 DOI: 10.3389/fphys.2013.00413] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/27/2013] [Indexed: 12/31/2022] Open
Abstract
The Cl−/HCO−3anion exchanger 2 (AE2) is known to be involved in intracellular pH (pHi) regulation and transepithelial acid-base transport. Early studies showed that AE2 gene expression is reduced in liver biopsies and blood mononuclear cells from patients with primary biliary cirrhosis (PBC), a disease characterized by chronic non-suppurative cholangitis associated with antimitochondrial antibodies (AMA) and other autoimmune phenomena. Microfluorimetric analysis of the Cl−/HCO−3 anion exchange (AE) in isolated cholangiocytes showed that the cAMP-stimulated AE activity is diminished in PBC compared to both healthy and diseased controls. More recently, it was found that miR-506 is upregulated in cholangiocytes of PBC patients and that AE2 may be a target of miR-506. Additional evidence for a pathogenic role of AE2 dysregulation in PBC was obtained with Ae2−/−a,b mice, which develop biochemical, histological, and immunologic alterations that resemble PBC (including development of serum AMA). Analysis of HCO−3 transport systems and pHi regulation in cholangiocytes from normal and Ae2−/−a,b mice confirmed that AE2 is the transporter responsible for the Cl−/HCO−3exchange in these cells. On the other hand, both Ae2+/+a,b and Ae2−/−a,b mouse cholangiocytes exhibited a Cl−-independent bicarbonate transport system, essentially a Na+-bicarbonate cotransport (NBC) system, which could contribute to pHi regulation in the absence of AE2.
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Affiliation(s)
- Axel R Concepcion
- Division of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), School of Medicine, University of Navarra, and Ciberehd Pamplona, Spain
| | - María Lopez
- Division of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), School of Medicine, University of Navarra, and Ciberehd Pamplona, Spain
| | - Alberto Ardura-Fabregat
- Division of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), School of Medicine, University of Navarra, and Ciberehd Pamplona, Spain
| | - Juan F Medina
- Division of Gene Therapy and Hepatology, Center for Applied Medical Research (CIMA), School of Medicine, University of Navarra, and Ciberehd Pamplona, Spain
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Péan N, Doignon I, Garcin I, Besnard A, Julien B, Liu B, Branchereau S, Spraul A, Guettier C, Humbert L, Schoonjans K, Rainteau D, Tordjmann T. The receptor TGR5 protects the liver from bile acid overload during liver regeneration in mice. Hepatology 2013; 58:1451-60. [PMID: 23686672 DOI: 10.1002/hep.26463] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/07/2013] [Accepted: 04/08/2013] [Indexed: 12/14/2022]
Abstract
UNLABELLED Many regulatory pathways are involved in liver regeneration after partial hepatectomy (PH) to initiate growth, protect liver cells, and sustain functions of the remnant liver. Bile acids (BAs), whose levels rise in the blood early after PH, stimulate both hepatocyte proliferation and protection, in part through their binding to the nuclear farnesoid X receptor (FXR). However, the effect of the BA receptor, TGR5 (G-protein-coupled BA receptor 1) after PH remains to be studied. Liver histology, hepatocyte proliferation, BA concentrations (plasma, bile, liver, urine, and feces), bile flow and composition, and cytokine production were studied in wild-type (WT) and TGR5 KO (knockout) mice before and after PH. BA composition (plasma, bile, liver, urine, and feces) was more hydrophobic in TGR5 KO than in WT mice. After PH, severe hepatocyte necrosis, prolonged cholestasis, exacerbated inflammatory response, and delayed regeneration were observed in TGR5 KO mice. Although hepatocyte adaptive response to post-PH BA overload was similar in WT and TGR5 KO mice, kidney and biliary adaptive responses were strongly impaired in TGR5 KO mice. Cholestyramine treatment, as well as Kupffer cell depletion, significantly improved the post-PH TGR5 KO mice phenotype. After bile duct ligation or upon a cholic acid-enriched diet, TGR5 KO mice exhibited more severe liver injury than WT as well as impaired BA elimination in urine. CONCLUSION TGR5 is crucial for liver protection against BA overload after PH, primarily through the control of bile hydrophobicity and cytokine secretion. In the absence of TGR5, intrahepatic stasis of abnormally hydrophobic bile and excessive inflammation, in association with impaired bile flow adaptation and deficient urinary BA efflux, lead to BA overload-induced liver injury and delayed regeneration.
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Affiliation(s)
- Noémie Péan
- INSERM U.757, Université Paris Sud, Orsay, France; Université Paris Sud, Orsay, France; Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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Collaco AM, Jakab RL, Hoekstra NE, Mitchell KA, Brooks A, Ameen NA. Regulated traffic of anion transporters in mammalian Brunner's glands: a role for water and fluid transport. Am J Physiol Gastrointest Liver Physiol 2013; 305:G258-75. [PMID: 23744739 PMCID: PMC3742856 DOI: 10.1152/ajpgi.00485.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The Brunner's glands of the proximal duodenum exert barrier functions through secretion of glycoproteins and antimicrobial peptides. However, ion transporter localization, function, and regulation in the glands are less clear. Mapping the subcellular distribution of transporters is an important step toward elucidating trafficking mechanisms of fluid transport in the gland. The present study examined 1) changes in the distribution of intestinal anion transporters and the aquaporin 5 (AQP5) water channel in rat Brunner's glands following second messenger activation and 2) anion transporter distribution in Brunner's glands from healthy and disease-affected human tissues. Cystic fibrosis transmembrane conductance regulator (CFTR), AQP5, sodium-potassium-coupled chloride cotransporter 1 (NKCC1), sodium-bicarbonate cotransporter (NBCe1), and the proton pump vacuolar ATPase (V-ATPase) were localized to distinct membrane domains and in endosomes at steady state. Carbachol and cAMP redistributed CFTR to the apical membrane. cAMP-dependent recruitment of CFTR to the apical membrane was accompanied by recruitment of AQP5 that was reversed by a PKA inhibitor. cAMP also induced apical trafficking of V-ATPase and redistribution of NKCC1 and NBCe1 to the basolateral membranes. The steady-state distribution of AQP5, CFTR, NBCe1, NKCC1, and V-ATPase in human Brunner's glands from healthy controls, cystic fibrosis, and celiac disease resembled that of rat; however, the distribution profiles were markedly attenuated in the disease-affected duodenum. These data support functional transport of chloride, bicarbonate, water, and protons by second messenger-regulated traffic in mammalian Brunner's glands under physiological and pathophysiological conditions.
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Affiliation(s)
- Anne M. Collaco
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut;
| | - Robert L. Jakab
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut;
| | - Nadia E. Hoekstra
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut;
| | - Kisha A. Mitchell
- 2Department of Pathology, Yale University School of Medicine, New Haven, Connecticut; and
| | - Amos Brooks
- 2Department of Pathology, Yale University School of Medicine, New Haven, Connecticut; and
| | - Nadia A. Ameen
- 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut; ,3Department Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut
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Parker MD, Boron WF. The divergence, actions, roles, and relatives of sodium-coupled bicarbonate transporters. Physiol Rev 2013; 93:803-959. [PMID: 23589833 PMCID: PMC3768104 DOI: 10.1152/physrev.00023.2012] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The mammalian Slc4 (Solute carrier 4) family of transporters is a functionally diverse group of 10 multi-spanning membrane proteins that includes three Cl-HCO3 exchangers (AE1-3), five Na(+)-coupled HCO3(-) transporters (NCBTs), and two other unusual members (AE4, BTR1). In this review, we mainly focus on the five mammalian NCBTs-NBCe1, NBCe2, NBCn1, NDCBE, and NBCn2. Each plays a specialized role in maintaining intracellular pH and, by contributing to the movement of HCO3(-) across epithelia, in maintaining whole-body pH and otherwise contributing to epithelial transport. Disruptions involving NCBT genes are linked to blindness, deafness, proximal renal tubular acidosis, mental retardation, and epilepsy. We also review AE1-3, AE4, and BTR1, addressing their relevance to the study of NCBTs. This review draws together recent advances in our understanding of the phylogenetic origins and physiological relevance of NCBTs and their progenitors. Underlying these advances is progress in such diverse disciplines as physiology, molecular biology, genetics, immunocytochemistry, proteomics, and structural biology. This review highlights the key similarities and differences between individual NCBTs and the genes that encode them and also clarifies the sometimes confusing NCBT nomenclature.
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Affiliation(s)
- Mark D Parker
- Dept. of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106-4970, USA.
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Wang X, Ye H, Ward CJ, Chu JYS, Masyuk TV, Larusso NF, Harris PC, Chow BKC, Torres VE. Insignificant effect of secretin in rodent models of polycystic kidney and liver disease. Am J Physiol Renal Physiol 2012; 303:F1089-98. [PMID: 22811488 DOI: 10.1152/ajprenal.00242.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Polycystic kidney (PKD) and liver (PLD) diseases cause significant morbidity and mortality. A large body of evidence indicates that cyclic AMP plays an important role in their pathogenesis. Clinical trials of drugs that reduce cyclic AMP levels in target tissues are now in progress. Secretin may contribute to adenylyl cyclase-dependent urinary concentration and is a major agonist of adenylyl cyclase in cholangiocytes. To investigate the role of secretin in PKD and PLD, we have studied the expression of secretin and the secretin receptor in rodent models orthologous to autosomal recessive (PCK rat) and dominant (Pkd2(-/WS25) mouse) PKD; the effects of exogenous secretin administration to PCK rats, PCK rats lacking circulating vasopressin (PCK(di/di)), and Pkd2(-/WS25) mice; and the impact of a nonfunctional secretin receptor on disease development in Pkd2(-/WS25):SCTR(-/-) double mutants. Renal and hepatic secretin and secretin receptor mRNA and plasma secretin were increased in both models, and secretin receptor protein was increased in the kidneys and liver of Pkd2(-/WS25) mice. However, exogenous secretin administered subcutaneously via osmotic pumps had minimal or negligible effects and the absence of a functional secretin receptor had no influence on the severity of PKD or PLD. Therefore, it is unlikely that by itself secretin plays a significant role in the pathogenesis of PKD and/or PLD.
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Affiliation(s)
- Xiaofang Wang
- Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
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Huang J, Shan J, Kim D, Liao J, Evagelidis A, Alper SL, Hanrahan JW. Basolateral chloride loading by the anion exchanger type 2: role in fluid secretion by the human airway epithelial cell line Calu-3. J Physiol 2012; 590:5299-316. [PMID: 22802585 DOI: 10.1113/jphysiol.2012.236919] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Anion exchanger type 2 (AE2 or SLC4A2) is an electroneutral Cl(-)/HCO(3)(-) exchanger expressed at the basolateral membrane of many epithelia. It is thought to participate in fluid secretion by airway epithelia. However, the role of AE2 in fluid secretion remains uncertain, due to the lack of specific pharmacological inhibitors, and because it is electrically silent and therefore does not contribute directly to short-circuit current (I(sc)). We have studied the role of AE2 in Cl(-) and fluid secretion by the airway epithelial cell line Calu-3. After confirming expression of its mRNA and protein, a knock-down cell line called AE2-KD was generated by lentivirus-mediated RNA interference in which AE2 mRNA and protein levels were reduced 90%. Suppressing AE2 increased the expression of the cystic fibrosis transmembrane conductance regulator (CFTR) by ∼70% without affecting the levels of NKCC1 (Na(+)-K(+)-2Cl(-) cotransporter) or NBCe1 (Na(+)-nHCO(3)(-) cotransporter). cAMP agonists stimulated fluid secretion by parental Calu-3 and scrambled shRNA cells >6.5-fold. In AE2-KD cells this response was reduced by ∼70%, and the secreted fluid exhibited elevated pH and [HCO(3)(-)] as compared with the control lines. Unstimulated equivalent short-circuit current (I(eq)) was elevated in AE2-KD cells, but the incremental response to forskolin was unaffected. The modest bumetanide-induced reductions in both I(eq) and fluid secretion were more pronounced in AE2-KD cells. Basolateral Cl(-)/HCO(3)(-) exchange measured by basolateral pH-stat in cells with permeabilized apical membranes was abolished in AE2-KD monolayers, and the intracellular alkalinization resulting from basolateral Cl(-) removal was reduced by ∼80% in AE2-KD cells. These results identify AE2 as a major pathway for basolateral Cl(-) loading during cAMP-stimulated secretion of Cl(-) and fluid by Calu-3 cells, and help explain the large bumetanide-insensitive component of fluid secretion reported previously in airway submucosal glands and some other epithelia.
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Affiliation(s)
- Junwei Huang
- Department of Physiology, McGill University, Montr´eal, QC, Canada
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Portincasa P, Calamita G. Water channel proteins in bile formation and flow in health and disease: when immiscible becomes miscible. Mol Aspects Med 2012; 33:651-64. [PMID: 22487565 DOI: 10.1016/j.mam.2012.03.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/29/2012] [Accepted: 03/31/2012] [Indexed: 12/19/2022]
Abstract
An essential function of the liver is the formation and secretion of bile, a complex aqueous solution of organic and inorganic compounds essential as route for the elimination of body cholesterol as unesterified cholesterol or as bile acids. In bile, a considerable amount of otherwise insoluble cholesterol is solubilized by carriers including two other classes of lipids, namely phospholipid and bile acids. Formation of bile and generation of bile flow are driven by the active secretion of bile acids, lipids and electrolytes into the canalicular and bile duct lumens followed by the parallel movement of water. Thus, water has to cross rapidly into and out of the cell interior driven by osmotic forces. Bile as a fluid, results from complicated interplay of hepatocyte and cholangiocyte uptake and secretion, concentration, by involving a number of transporters of lipids, anions, cations, and water. The discovery of the aquaporin water channels, has clarified the mechanisms by which water, the major component of bile (more than 95%), moves across the hepatobiliary epithelia. This review is focusing on novel acquisitions in liver membrane lipidic and water transport and functional participation of aquaporin water channels in multiple aspects of hepatobiliary fluid balance. Involvement of aquaporins in a series of clinically relevant hepatobiliary disorders are also discussed.
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Affiliation(s)
- Piero Portincasa
- University of Bari Medical School, Clinica Medica A. Murri, Department of Biomedical Sciences and Human Oncology, Policlinico Hospital, 70124 Bari, Italy.
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Carmosino M, Procino G, Tamma G, Mannucci R, Svelto M, Valenti G. Trafficking and phosphorylation dynamics of AQP4 in histamine-treated human gastric cells. Biol Cell 2012; 99:25-36. [PMID: 16895520 DOI: 10.1042/bc20060068] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION AQP4 (aquaporin 4) internalization and a concomitant decrease in the osmotic water permeability coefficient (Pf) after histamine exposure has been reported in AQP4-transfected gastric HGT1 cells. RESULTS In the present study we report that AQP4 internalization is followed by an increase in AQP4 phosphorylation. Histamine treatment for 30 min resulted in an approx. 10-fold increase in AQP4 phosphorylation that was inhibited by 1 microM H89, a specific PKA (protein kinase A) inhibitor, but not by PKC (protein kinase C) and CK2 inhibitors. Moreover, measurement of PKA activity after 30 min of histamine treatment showed that PKA activity was approx. 3-fold higher compared with basal conditions. AQP4 phosphorylation was prevented in cells treated with histamine for 30 min after pre-incubation with PAO (phenylarsine oxide), an inhibitor of protein endocytosis. Using an endo-exocytosis assay we showed that, after histamine washed out, internalized AQP4 recycled back to the cell surface, even in cells in which de novo protein synthesis was inhibited by cycloheximide. CONCLUSIONS Phosphorylation experiments, combined with immunolocalization studies, indicated that AQP4 phosphorylation is mediated by PKA and occurs subsequently to its internalization in late endosomes. We suggest that phosphorylation might be a mechanism involved in retaining AQP4 in a vesicle-recycling compartment.
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Affiliation(s)
- Monica Carmosino
- Department of General and Environmental Physiology, University of Bari, Via Amendola 165/A, 70126 Bari, Italy
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Ameli PA, Madan M, Chigurupati S, Yu A, Chan SL, Pattisapu JV. Effect of acetazolamide on aquaporin-1 and fluid flow in cultured choroid plexus. ACTA NEUROCHIRURGICA. SUPPLEMENT 2012; 113:59-64. [PMID: 22116425 DOI: 10.1007/978-3-7091-0923-6_13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Acetazolamide (AZA), used in treatment of early or infantile hydrocephalus, is effective in some cases, while its effect on the choroid plexus (CP) remains ill-defined. The drug reversibly inhibits aquaporin-4 (AQP4), the most ubiquitous "water pore" in the brain, and perhaps modulation of AQP1 (located apically on CP cells) by AZA may reduce cerebrospinal fluid (CSF) production. We sought to elucidate the effect of AZA on AQP1 and fluid flow in CP cell cultures.CP tissue culture from 10-day Sprague-Dawley rats and a TRCSF-B cell line were grown on Transwell permeable supports and treated with 100 μM AZA. Fluid assays to assess direction and extent of fluid flow, and AQP1 expression patterns by immunoblot, Immuncytochemistry (ICC), and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were performed.Immunoblots and ICC analyses showed a decrease in AQP1 protein shortly after AZA treatment (lowest at 12 h), with transient AQP1 reduction mediated by mRNA expression (lowest at 6 h). Transwell fluid assays indicated a fluid shift at 2 h, before significant changes in AQP1 mRNA or protein levels.Timing of AZA effect on AQP1 suggests the drug alters protein transcription, while affecting fluid flow by a concomitant method. It is plausible that other mechanisms account for these phenomena, as the processes may occur independently.
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Affiliation(s)
- Pouya A Ameli
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, USA
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Úriz M, Sáez E, Prieto J, Medina JF, Banales JM. Ursodeoxycholic acid is conjugated with taurine to promote secretin-stimulated biliary hydrocholeresis in the normal rat. PLoS One 2011; 6:e28717. [PMID: 22194894 PMCID: PMC3237485 DOI: 10.1371/journal.pone.0028717] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 11/14/2011] [Indexed: 12/15/2022] Open
Abstract
Background & Aims Secretin induces bicarbonate-rich hydrocholeresis in healthy individuals, but not in untreated patients with primary biliary cirrhosis (PBC). Ursodeoxycholic acid (UDCA) – the first choice treatment for PBC – restores the secretin response. Compared with humans, secretin has poor effect in experimental normal-rat models with biliary drainage, although it may elicit hydrocholeresis when the bile-acid pool is maintained. In view of the benefits of UDCA in PBC, we used normal-rat models to unravel the acute contribution of UDCA (and/or taurine-conjugated TUDCA) for eliciting the biliary secretin response. Methods Intravascular and/or intrabiliary administration of agonists and inhibitors was performed in normal rats with biliary monitoring. Secretin/bile-acid interplay was analyzed in 3D cultured rat cholangiocytes that formed expansive cystic structures with intralumenal hydroionic secretion. Results In vivo, secretin stimulates hydrocholeresis upon UDCA/TUDCA infusion, but does not modify the intrinsic hypercholeretic effect of dehydrocholic acid (DHCA). The former effect is dependent on microtubule polymerization, and involves PKCα, PI3K and MEK pathways, as shown by colchicine (i.p.) and retrograde biliary inhibitors. In vitro, while secretin alone accelerates the spontaneous expansion of 3D-cystic structures, this effect is enhanced in the presence of TUDCA, but not UDCA or DHCA. Experiments with inhibitors and Ca2+-chelator confirmed that the synergistic effect of secretin plus TUDCA involves microtubules, intracellular Ca2+, PKCα, PI3K, PKA and MEK pathways. Gene silencing also demonstrated the involvement of the bicarbonate extruder Ae2. Conclusions UDCA is conjugated in order to promote secretin-stimulated hydrocholeresis in rats through Ae2, microtubules, intracellular Ca2+, PKCα, PI3K, PKA, and MEK.
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Affiliation(s)
- Miriam Úriz
- Division of Gene Therapy and Hepatology, CIMA Clinic and School of Medicine, University of Navarra, Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
| | - Elena Sáez
- Division of Gene Therapy and Hepatology, CIMA Clinic and School of Medicine, University of Navarra, Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
| | - Jesús Prieto
- Division of Gene Therapy and Hepatology, CIMA Clinic and School of Medicine, University of Navarra, Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
| | - Juan F. Medina
- Division of Gene Therapy and Hepatology, CIMA Clinic and School of Medicine, University of Navarra, Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
- * E-mail: (JB); (JM)
| | - Jesús M. Banales
- Division of Gene Therapy and Hepatology, CIMA Clinic and School of Medicine, University of Navarra, Centro de Investigación Biomédica en Red en el Área temática de Enfermedades Hepáticas y Digestivas, Pamplona, Spain
- * E-mail: (JB); (JM)
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Medina JF. Role of the anion exchanger 2 in the pathogenesis and treatment of primary biliary cirrhosis. Dig Dis 2011; 29:103-12. [PMID: 21691115 DOI: 10.1159/000324144] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The essential anion exchanger (AE) involved in biliary bicarbonate secretion is AE2/SLC4A2, a membrane protein which has also been recognized to be relevant for the regulation of the intracellular pH (pH(i)) in several cell types. Previously, we reported that the expression of AE2 mRNA is diminished in liver biopsies and peripheral blood mononuclear cells from patients with primary biliary cirrhosis (PBC). Immunohistochemical studies indicated that the expression of the AE2 protein is decreased in the bile ducts and hepatocytes in PBC livers. Moreover, we found that bile duct cells isolated from PBC patients and cultured for a few passages exhibit defective Na(+)-independent Cl(-)/HCO(3)(-) exchange. Interestingly, positron emission tomography studies have shown that PBC patients, even at early stages of the disease, fail to secrete bicarbonate to bile in response to secretin, a defect that can be partially reversed after several months of treatment with ursodeoxycholic acid. Altogether, these findings sustain our hypothesis that dysfunctions related to AE2 might have a role in the pathogenesis of PBC. Inadequate AE2 function in lymphocytes may disturb pH(i) regulation in these cells and alter immune homeostasis leading to autoimmunity. On the other hand, reduced AE2 in cholangiocytes could cause cholestasis and oxidative stress of bile duct cells. Cholangiocyte changes, together with altered immune homeostasis, could favor the development of antimitochondrial antibodies and the autoimmune attack on biliary ducts. Our recent findings that Ae2(a,b)-deficient mice indeed display most of these features strongly support the notion that AE2 abnormalities may be involved in the pathogenesis of PBC.
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Affiliation(s)
- Juan F Medina
- Division of Gene Therapy and Hepatology - Liver Unit, School of Medicine, Clinic and CIMA University of Navarra, and Ciberehd, Pamplona, Spain.
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Zelenina M. Regulation of brain aquaporins. Neurochem Int 2010; 57:468-88. [DOI: 10.1016/j.neuint.2010.03.022] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/21/2010] [Accepted: 03/31/2010] [Indexed: 01/27/2023]
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Aquaporins: relevance to cerebrospinal fluid physiology and therapeutic potential in hydrocephalus. Cerebrospinal Fluid Res 2010; 7:15. [PMID: 20860832 PMCID: PMC2949735 DOI: 10.1186/1743-8454-7-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/22/2010] [Indexed: 11/20/2022] Open
Abstract
The discovery of a family of membrane water channel proteins called aquaporins, and the finding that aquaporin 1 was located in the choroid plexus, has prompted interest in the role of aquaporins in cerebrospinal fluid (CSF) production and consequently hydrocephalus. While the role of aquaporin 1 in choroidal CSF production has been demonstrated, the relevance of aquaporin 1 to the pathophysiology of hydrocephalus remains debated. This has been further hampered by the lack of a non-toxic specific pharmacological blocking agent for aquaporin 1. In recent times aquaporin 4, the most abundant aquaporin within the brain itself, which has also been shown to have a role in brain water physiology and relevance to brain oedema in trauma and tumours, has become an alternative focus of attention for hydrocephalus research. This review summarises current knowledge and concepts in relation to aquaporins, specifically aquaporin 1 and 4, and hydrocephalus. It also examines the relevance of aquaporins as potential therapeutic targets in hydrocephalus and other CSF circulation disorders.
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Huebert RC, Vasdev MM, Shergill U, Das A, Huang BQ, Charlton MR MR, LaRusso NF, Shah VH. Aquaporin-1 facilitates angiogenic invasion in the pathological neovasculature that accompanies cirrhosis. Hepatology 2010; 52:238-48. [PMID: 20578142 PMCID: PMC2928054 DOI: 10.1002/hep.23628] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
UNLABELLED Increasing evidence suggests that hepatic fibrosis and pathological angiogenesis are interdependent processes that occur in parallel. Endothelial cell invasion is requisite for angiogenesis, and thus studies of the mechanisms governing liver endothelial cell (LEC) invasion during cirrhosis are of great importance. Emerging research implicates amoeboid-type motility and membrane blebbing as features that may facilitate invasion through matrix-rich microenvironments. Aquaporins (AQPs) are integral membrane water channels, recognized for their importance in epithelial secretion and absorption. However, recent studies also suggest links between water transport and cell motility or invasion. Therefore, the purpose of this study was to test the hypothesis that AQP-1 is involved in amoeboid motility and angiogenic invasion during cirrhosis. AQP-1 expression and localization was examined in normal and cirrhotic liver tissues derived from human and mouse. AQP-1 levels were modulated in LEC using retroviral overexpression or small interfering RNA (siRNA) knockdown and functional effects on invasion, membrane blebbing dynamics, and osmotic water permeability were assayed. Results demonstrate that AQP-1 is up-regulated in the small, angiogenic, neovasculature within the fibrotic septa of cirrhotic liver. AQP-1 overexpression promotes fibroblast growth factor (FGF)-induced dynamic membrane blebbing in LEC, which is sufficient to augment invasion through extracellular matrix. Additionally, AQP-1 localizes to plasma membrane blebs, where it increases osmotic water permeability and locally facilitates the rapid, trans-membrane flux of water. CONCLUSION AQP-1 enhances osmotic water permeability and FGF-induced dynamic membrane blebbing in LEC and thereby drives invasion and pathological angiogenesis during cirrhosis.
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Affiliation(s)
- Robert C. Huebert
- Gastroenterology Research Unit, Mayo Clinic and Foundation, Rochester, MN 55905,Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Meher M. Vasdev
- Gastroenterology Research Unit, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Uday Shergill
- Gastroenterology Research Unit, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Amitava Das
- Gastroenterology Research Unit, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Bing Q. Huang
- Center for Basic Research in Digestive Diseases, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Michael R. Charlton MR
- Center for Basic Research in Digestive Diseases, Mayo Clinic and Foundation, Rochester, MN 55905,Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Nicholas F. LaRusso
- Center for Basic Research in Digestive Diseases, Mayo Clinic and Foundation, Rochester, MN 55905,Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905,Center for Cell Signaling, Mayo Clinic and Foundation, Rochester, MN 55905
| | - Vijay H. Shah
- Gastroenterology Research Unit, Mayo Clinic and Foundation, Rochester, MN 55905,Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905,Center for Cell Signaling, Mayo Clinic and Foundation, Rochester, MN 55905
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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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Uriarte I, Banales JM, Sáez E, Arenas F, Oude Elferink RPJ, Prieto J, Medina JF. Bicarbonate secretion of mouse cholangiocytes involves Na(+)-HCO(3)(-) cotransport in addition to Na(+)-independent Cl(-)/HCO(3)(-) exchange. Hepatology 2010; 51:891-902. [PMID: 20041402 DOI: 10.1002/hep.23403] [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: 12/25/2022]
Abstract
UNLABELLED Bicarbonate secretion from cholangiocytes is required for appropriate adjustment of primary canalicular bile along the biliary tract. In human and rat cholangiocytes, bicarbonate secretion is mediated by anion exchanger (AE) 2, an electroneutral Na(+)-independent Cl(-)/HCO(3) (-) AE also involved in intracellular pH (pH(i)) regulation. In Ae2(a,b)-deficient mice, pH(i) is increased in lymphocytes and fibroblasts, whereas it is surprisingly normal in cholangiocytes. Here, we analyze the mechanisms for HCO(3) (-) secretion in cultured Ae2(a,b) (+/+) and Ae2(a,b) (-/-) mouse cholangiocytes by microfluorimetric measurement of pH(i) changes upon established perfusion maneuvers. Cl(-) withdrawal by isethionate-based perfusions showed that Ae2(a,b) (+/+) but not Ae2(a,b) (-/-) mouse cholangiocytes can display Cl(-)/HCO(3) (-) exchange, which is therefore entirely mediated by Ae2. Nevertheless, simultaneous withdrawal of Cl(-) and Na(+) revealed that mouse cholangiocytes possess an additional transport activity for HCO(3) (-) secretion not observed in control rat cholangiocytes. Propionate-based maneuvers indicated that this supplemental Na(+)-driven HCO(3) (-)-secreting activity is Cl(-)-independent, consistent with a Na(+)-HCO(3) (-) cotransport (NBC). NBC activity is greater in Ae2(a,b) (-/-) than Ae2(a,b) (+/+) mouse cholangiocytes, and membrane-depolarization experiments showed that it is electrogenic. Consistent with the potential role of Slc4a4/Nbc1 as the involved transporter, Ae2(a,b) (-/-) mouse cholangiocytes exhibit up-regulated expression of this electrogenic NBC carrier. Whereas Ae2-mediated Cl(-)/HCO(3) (-) exchange in Ae2(a,b) (+/+) mouse cholangiocytes is stimulated by cyclic adenosine monophosphate (cAMP) and acetylcholine, the NBC activity is down-regulated by cAMP and adenosine triphosphate (ATP) in Ae2(a,b) (-/-) mouse cholangiocytes. Polarized Ae2(a,b) (-/-) mouse cholangiocytes placed in Ussing chambers show decreased (but not abolished) cAMP-dependent Cl(-) current and increased ATP-dependent/Ca(2+)-activated Cl(-) secretion, which run in parallel with decreased cystic fibrosis transmembrane conductance regulator messenger RNA expression and increased intracellular Ca(2+) levels. CONCLUSION Bicarbonate secretion in mouse cholangiocytes involves two differentially regulated activities: Ae2-mediated Cl(-)/HCO(3) (-) exchange and Na(+)-HCO(3) (-) cotransport.
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Affiliation(s)
- Iker Uriarte
- Division of Gene Therapy and Hepatology-Liver Unit, CIMA, CUN, and School of Medicine, University of Navarra, and Ciberehd, Pamplona, Spain
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Chu JYS, Lee LTO, Lai CH, Vaudry H, Chan YS, Yung WH, Chow BKC. Secretin as a neurohypophysial factor regulating body water homeostasis. Proc Natl Acad Sci U S A 2009; 106:15961-6. [PMID: 19805236 PMCID: PMC2747226 DOI: 10.1073/pnas.0903695106] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Indexed: 12/23/2022] Open
Abstract
Hypothalamic magnocellular neurons express either one of the neurohypophysial hormones, vasopressin or oxytocin, along with different neuropeptides or neuromodulators. Axonal terminals of these neurons are generally accepted to release solely the two hormones but not others into the circulation. Here, we show that secretin, originally isolated from upper intestinal mucosal extract, is present throughout the hypothalamo-neurohypophysial axis and that it is released from the posterior pituitary under plasma hyperosmolality conditions. In the hypothalamus, it stimulates vasopressin expression and release. Considering these findings together with our previous findings that show a direct effect of secretin on renal water reabsorption, we propose here that secretin works at multiple levels in the hypothalamus, pituitary, and kidney to regulate water homeostasis. Findings presented here challenge previous understanding regarding the neurohypophysis and could provide new concepts in treating disorders related to osmoregulation.
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Affiliation(s)
| | | | - C. H. Lai
- Department of Physiology and Research Centre of Heart, Brain, Hormone and Healthy Aging, University of Hong Kong, Hong Kong, China
| | - H. Vaudry
- Institut National de la Santé et de la Recherche Médicale Unité 413, Laboratory of Cellular and Molecular Neuroendocrinology, University of Rouen, 76821 Mont-Saint-Aignan, France; and
| | - Y. S. Chan
- Department of Physiology and Research Centre of Heart, Brain, Hormone and Healthy Aging, University of Hong Kong, Hong Kong, China
| | - W. H. Yung
- Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
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Jessner W, Zsembery A, Graf J. Transcellular water transport in hepatobiliary secretion and role of aquaporins in liver. Wien Med Wochenschr 2009; 158:565-9. [PMID: 18998074 DOI: 10.1007/s10354-008-0597-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 03/28/2008] [Indexed: 01/11/2023]
Abstract
In the context of the osmotic model of bile formation, we used isolated rat hepatocyte couplets and performed volume measurements by video image analysis to analyze the transport of water between the bile canalicular lumen, liver cells and the surrounding bathing medium. Increasing bath osmolarity by the addition of sucrose led to shrinkage of cells that preceded shrinkage of the canalicular lumen by approx. 1 sec. Thermodynamic modeling of water transport across the basolateral and apical cell membranes and across a paracellular pathway (tight junctions) revealed high hydraulic water permeabilities of both cell membranes of approx. 3*10(-4) cm*sec(-1)*(osmol/kg)(-1) indicating transcellular water flux between bathing medium and bile. Tight junctions exhibited low water permeability but allowed for electrolyte permeation that enables canalicular spaces to shrink below van't Hoff equilibrium during the osmotic maneuver. The results are discussed with respect to the role of different types of membrane aquaporins being expressed in hepatocytes.
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Affiliation(s)
- Wolfgang Jessner
- Department of Pathophysiology, Medical University of Vienna, Vienna, Austria.
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Alper SL. Molecular physiology and genetics of Na+-independent SLC4 anion exchangers. J Exp Biol 2009; 212:1672-83. [PMID: 19448077 PMCID: PMC2683012 DOI: 10.1242/jeb.029454] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2009] [Indexed: 01/12/2023]
Abstract
Plasmalemmal Cl(-)/HCO(3)(-) exchangers are encoded by the SLC4 and SLC26 gene superfamilies, and function to regulate intracellular pH, [Cl(-)] and cell volume. The Cl(-)/HCO(3)(-) exchangers of polarized epithelial cells also contribute to transepithelial secretion and reabsorption of acid-base equivalents and Cl(-). This review focuses on Na(+)-independent electroneutral Cl(-)/HCO(3)(-) exchangers of the SLC4 family. Human SLC4A1/AE1 mutations cause the familial erythroid disorders of spherocytic anemia, stomatocytic anemia and ovalocytosis. A largely discrete set of AE1 mutations causes familial distal renal tubular acidosis. The Slc4a2/Ae2(-/-) mouse dies before weaning with achlorhydria and osteopetrosis. A hypomorphic Ae2(-/-) mouse survives to exhibit male infertility with defective spermatogenesis and a syndrome resembling primary biliary cirrhosis. A human SLC4A3/AE3 polymorphism is associated with seizure disorder, and the Ae3(-/-) mouse has increased seizure susceptibility. The transport mechanism of mammalian SLC4/AE polypeptides is that of electroneutral Cl(-)/anion exchange, but trout erythroid Ae1 also mediates Cl(-) conductance. Erythroid Ae1 may mediate the DIDS-sensitive Cl(-) conductance of mammalian erythrocytes, and, with a single missense mutation, can mediate electrogenic SO(4)(2-)/Cl(-) exchange. AE1 trafficking in polarized cells is regulated by phosphorylation and by interaction with other proteins. AE2 exhibits isoform-specific patterns of acute inhibition by acidic intracellular pH and independently by acidic extracellular pH. In contrast, AE2 is activated by hypertonicity and, in a pH-independent manner, by ammonium and by hypertonicity. A growing body of structure-function and interaction data, together with emerging information about physiological function and structure, is advancing our understanding of SLC4 anion exchangers.
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Affiliation(s)
- Seth L Alper
- Renal Division and Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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Aquaporin water channels in mammals. Clin Exp Nephrol 2008; 13:107-117. [PMID: 19085041 DOI: 10.1007/s10157-008-0118-6] [Citation(s) in RCA: 253] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 11/04/2008] [Indexed: 12/16/2022]
Abstract
Water channels, aquaporins (AQPs), are a family of small integral plasma membrane proteins that primarily transport water across the plasma membrane. There are 13 members (AQP0-12) in humans. This number is final as the human genome project has been completed. They are divided into three subgroups based on the primary sequences: water selective AQPs (AQP0, 1, 2, 4, 5, 6, 8), aquaglyceroporins (AQP3, 7, 9, 10), and superaquaporins (AQP11, 12). Since no specific inhibitors are yet available, functional roles of AQPs are suggested by AQP null mice and humans. Abnormal water metabolism was shown with AQP1, 2, 3, 4, 5 null mice, especially with AQP2 null mice: fatal at neonate due to diabetes insipidus. Abnormal glycerol transport was shown with AQP3, 7, 9 null mice, although they appeared normal. AQP0 null mice suffer from cataracts, although the pathogenesis is not clear. Unexpectedly, AQP11 null mice die from uremia as a result of polycystic kidneys. Interestingly, AQP6, 8, 10, 12 null mice are almost normal. AQP null humans have been reported with AQP0, 1, 2, 3, 7: only AQP2 null humans show an outstanding phenotype, diabetes insipidus. This review summarizes the current knowledge on all mammalian AQPs and hopefully will stimulate future research in both clinical and basic fields.
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Banales JM, Masyuk TV, Bogert PS, Huang BQ, Gradilone SA, Lee SO, Stroope AJ, Masyuk AI, Medina JF, LaRusso NF. Hepatic cystogenesis is associated with abnormal expression and location of ion transporters and water channels in an animal model of autosomal recessive polycystic kidney disease. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:1637-46. [PMID: 18988797 DOI: 10.2353/ajpath.2008.080125] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Polycystic kidney (PCK) rats are a spontaneous model of autosomal recessive polycystic kidney disease that exhibit cholangiocyte-derived liver cysts. We have previously reported that in normal cholangiocytes a subset of vesicles contain three proteins (ie, the water channel AQP1, the chloride channel CFTR, and the anion exchanger AE2) that account for ion-driven water transport. Thus, we hypothesized that altered expression and location of these functionally related proteins contribute to hepatic cystogenesis. We show here that under basal conditions and in response to secretin and hypotonicity, cysts from PCK rats expanded to a greater degree than cysts formed by normal bile ducts. Quantitative reverse transcriptase-polymerase chain reaction, immunoblot analysis, and confocal and immunoelectron microscopy all indicated increased expression of these three proteins in PCK cholangiocytes versus normal cholangiocytes. AQP1, CFTR, and AE2 were localized preferentially to the apical membrane in normal rats while overexpressed at the basolateral membrane in PCK rats. Exposure of the cholangiocyte basolateral membrane to CFTR inhibitors [5-nitro-2-(3-phenylpropylamino)-benzoic acid and CFTRinh172], or Cl(-)/HCO(3)(-) exchange inhibitors (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid disodium salt hydrate and 4-acetamido-4'-isothiocyanato-2,2'-stilbenedisulfonic acid disodium salt hydrate) blocked secretin-stimulated fluid accumulation in PCK but not in normal cysts. Our data suggest that hepatic cystogenesis in autosomal recessive polycystic kidney disease may involve increased fluid accumulation because of overexpression and abnormal location of AQP1, CFTR, and AE2 in cystic cholangiocytes. Therapeutic interventions that block the activation of these proteins might inhibit cyst expansion in polycystic liver disease.
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Affiliation(s)
- Jesús M Banales
- Miles and Shirley Fiterman Center for Digestive Diseases, Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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