1
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Schreiber R, Ousingsawat J, Kunzelmann K. The anoctamins: Structure and function. Cell Calcium 2024; 120:102885. [PMID: 38642428 DOI: 10.1016/j.ceca.2024.102885] [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: 02/21/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/22/2024]
Abstract
When activated by increase in intracellular Ca2+, anoctamins (TMEM16 proteins) operate as phospholipid scramblases and as ion channels. Anoctamin 1 (ANO1) is the Ca2+-activated epithelial anion-selective channel that is coexpressed together with the abundant scramblase ANO6 and additional intracellular anoctamins. In salivary and pancreatic glands, ANO1 is tightly packed in the apical membrane and secretes Cl-. Epithelia of airways and gut use cystic fibrosis transmembrane conductance regulator (CFTR) as an apical Cl- exit pathway while ANO1 supports Cl- secretion mainly by facilitating activation of luminal CFTR and basolateral K+ channels. Under healthy conditions ANO1 modulates intracellular Ca2+ signals by tethering the endoplasmic reticulum, and except of glands its direct secretory contribution as Cl- channel might be small, compared to CFTR. In the kidneys ANO1 supports proximal tubular acid secretion and protein reabsorption and probably helps to excrete HCO3-in the collecting duct epithelium. However, under pathological conditions as in polycystic kidney disease, ANO1 is strongly upregulated and may cause enhanced proliferation and cyst growth. Under pathological condition, ANO1 and ANO6 are upregulated and operate as secretory channel/phospholipid scramblases, partly by supporting Ca2+-dependent processes. Much less is known about the role of other epithelial anoctamins whose potential functions are discussed in this review.
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Affiliation(s)
- Rainer Schreiber
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany.
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2
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Li X, Wang Y, Zhang L, Yao S, Liu Q, Jin H, Tuo B. The role of anoctamin 1 in liver disease. J Cell Mol Med 2024; 28:e18320. [PMID: 38685684 PMCID: PMC11058335 DOI: 10.1111/jcmm.18320] [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: 11/08/2023] [Revised: 03/21/2024] [Accepted: 04/03/2024] [Indexed: 05/02/2024] Open
Abstract
Liver diseases include all types of viral hepatitis, alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), cirrhosis, liver failure (LF) and hepatocellular carcinoma (HCC). Liver disease is now one of the leading causes of disease and death worldwide, which compels us to better understand the mechanisms involved in the development of liver diseases. Anoctamin 1 (ANO1), a calcium-activated chloride channel (CaCC), plays an important role in epithelial cell secretion, proliferation and migration. ANO1 plays a key role in transcriptional regulation as well as in many signalling pathways. It is involved in the genesis, development, progression and/or metastasis of several tumours and other diseases including liver diseases. This paper reviews the role and molecular mechanisms of ANO1 in the development of various liver diseases, aiming to provide a reference for further research on the role of ANO1 in liver diseases and to contribute to the improvement of therapeutic strategies for liver diseases by regulating ANO1.
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Affiliation(s)
- Xin Li
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Yongfeng Wang
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Li Zhang
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Shun Yao
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Qian Liu
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Hai Jin
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative Innovation Center of Tissue Damage Repair and Regenerative Medicine of Zunyi Medical UniversityZunyiChina
| | - Biguang Tuo
- Department of Gastroenterology, Digestive Disease HospitalAffiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative Innovation Center of Tissue Damage Repair and Regenerative Medicine of Zunyi Medical UniversityZunyiChina
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3
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Reshetnyak VI, Maev IV. New insights into the pathogenesis of primary biliary cholangitis asymptomatic stage. World J Gastroenterol 2023; 29:5292-5304. [PMID: 37899787 PMCID: PMC10600802 DOI: 10.3748/wjg.v29.i37.5292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/10/2023] [Accepted: 09/14/2023] [Indexed: 09/25/2023] Open
Abstract
Primary biliary cholangitis (PBC) is a chronic cholestatic progressive liver disease and one of the most important progressive cholangiopathies in adults. Damage to cholangiocytes triggers the development of intrahepatic cholestasis, which progresses to cirrhosis in the terminal stage of the disease. Accumulating data indicate that damage to biliary epithelial cells [(BECs), cholangiocytes] is most likely associated with the intracellular accumulation of bile acids, which have potent detergent properties and damaging effects on cell membranes. The mechanisms underlying uncontrolled bile acid intake into BECs in PBC are associated with pH change in the bile duct lumen, which is controlled by the bicarbonate (HCO3-) buffer system "biliary HCO3- umbrella". The impaired production and entry of HCO3- from BECs into the bile duct lumen is due to epigenetic changes in expression of the X-linked microRNA 506. Based on the growing body of knowledge on the molecular mechanisms of cholangiocyte damage in patients with PBC, we propose a hypothesis explaining the pathogenesis of the first morphologic (ductulopenia), immunologic (antimitochondrial autoantibodies) and clinical (weakness, malaise, rapid fatigue) signs of the disease in the asymptomatic stage. This review focuses on the consideration of these mechanisms.
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Affiliation(s)
- Vasiliy Ivanovich Reshetnyak
- Department of Propaedeutics of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
| | - Igor Veniaminovich Maev
- Department of Propaedeutics of Internal Diseases and Gastroenterology, A.I. Yevdokimov Moscow State University of Medicine and Dentistry, Moscow 127473, Russia
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4
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Kulkarni S, Li Q, Singhi AD, Liu S, Monga SP, Feranchak AP. TMEM16A partners with mTOR to influence pathways of cell survival, proliferation, and migration in cholangiocarcinoma. Am J Physiol Gastrointest Liver Physiol 2023; 325:G122-G134. [PMID: 37219012 PMCID: PMC10390053 DOI: 10.1152/ajpgi.00270.2022] [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: 11/11/2022] [Revised: 05/04/2023] [Accepted: 05/17/2023] [Indexed: 05/24/2023]
Abstract
Expression of transmembrane protein 16 A (TMEM16A), a calcium activated chloride channel, is elevated in some human cancers and impacts tumor cell proliferation, metastasis, and patient outcome. Evidence presented here uncovers a molecular synergy between TMEM16A and mechanistic/mammalian target of rapamycin (mTOR), a serine-threonine kinase that is known to promote cell survival and proliferation in cholangiocarcinoma (CCA), a lethal cancer of the secretory cells of bile ducts. Analysis of gene and protein expression in human CCA tissue and CCA cell line detected elevated TMEM16A expression and Cl- channel activity. The Cl- channel activity of TMEM16A impacted the actin cytoskeleton and the ability of cells to survive, proliferate, and migrate as revealed by pharmacological inhibition studies. The basal activity of mTOR, too, was elevated in the CCA cell line compared with the normal cholangiocytes. Molecular inhibition studies provided further evidence that TMEM16A and mTOR were each able to influence the regulation of the other's activity or expression respectively. Consistent with this reciprocal regulation, combined TMEM16A and mTOR inhibition produced a greater loss of CCA cell survival and migration than their individual inhibition alone. Together these data reveal that the aberrant TMEM16A expression and cooperation with mTOR contribute to a certain advantage in CCA.NEW & NOTEWORTHY This study points to the dysregulation of transmembrane protein 16 A (TMEM16A) expression and activity in cholangiocarcinoma (CCA), the inhibition of which has functional consequences. Dysregulated TMEM16A exerts an influence on the regulation of mechanistic/mammalian target of rapamycin (mTOR) activity. Moreover, the reciprocal regulation of TMEM16A by mTOR demonstrates a novel connection between these two protein families. These findings support a model in which TMEM16A intersects the mTOR pathway to regulate cell cytoskeleton, survival, proliferation, and migration in CCA.
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Affiliation(s)
- Sucheta Kulkarni
- Division of Gastroenterology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Qin Li
- Division of Gastroenterology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Aatur D Singhi
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Silvia Liu
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Satdarshan P Monga
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Andrew P Feranchak
- Division of Gastroenterology, Department of Pediatrics, Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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5
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Truong JK, Li J, Li Q, Pachura K, Rao A, Gumber S, Fuchs CD, Feranchak AP, Karpen SJ, Trauner M, Dawson PA. Active enterohepatic cycling is not required for the choleretic actions of 24-norUrsodeoxycholic acid in mice. JCI Insight 2023; 8:e149360. [PMID: 36787187 PMCID: PMC10070106 DOI: 10.1172/jci.insight.149360] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
The pronounced choleretic properties of 24-norUrsodeoxycholic acid (norUDCA) to induce bicarbonate-rich bile secretion have been attributed to its ability to undergo cholehepatic shunting. The goal of this study was to identify the mechanisms underlying the choleretic actions of norUDCA and the role of the bile acid transporters. Here, we show that the apical sodium-dependent bile acid transporter (ASBT), organic solute transporter-α (OSTα), and organic anion transporting polypeptide 1a/1b (OATP1a/1b) transporters are dispensable for the norUDCA stimulation of bile flow and biliary bicarbonate secretion. Chloride channels in biliary epithelial cells provide the driving force for biliary secretion. In mouse large cholangiocytes, norUDCA potently stimulated chloride currents that were blocked by siRNA silencing and pharmacological inhibition of calcium-activated chloride channel transmembrane member 16A (TMEM16A) but unaffected by ASBT inhibition. In agreement, blocking intestinal bile acid reabsorption by coadministration of an ASBT inhibitor or bile acid sequestrant did not impact norUDCA stimulation of bile flow in WT mice. The results indicate that these major bile acid transporters are not directly involved in the absorption, cholehepatic shunting, or choleretic actions of norUDCA. Additionally, the findings support further investigation of the therapeutic synergy between norUDCA and ASBT inhibitors or bile acid sequestrants for cholestatic liver disease.
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Affiliation(s)
- Jennifer K. Truong
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Jianing Li
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Qin Li
- Department of Pediatrics, University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kimberly Pachura
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Anuradha Rao
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Sanjeev Gumber
- Division of Pathology and Laboratory Medicine, Yerkes National Research Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Claudia Daniela Fuchs
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Andrew P. Feranchak
- Department of Pediatrics, University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Saul J. Karpen
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Paul A. Dawson
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, USA
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6
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Yuan L, Tang Y, Yin L, Lin X, Luo Z, Wang S, Li J, Liang P, Jiang B. The role of Transmembrane Protein 16A (TMEM16A) in pulmonary hypertension. Cardiovasc Pathol 2023; 65:107525. [PMID: 36781068 DOI: 10.1016/j.carpath.2023.107525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/13/2023] Open
Abstract
Transmembrane protein 16A (TMEM16A), a member of the TMEM16 family, is the molecular basis of Ca2+-activated chloride channels (CaCCs) and is involved in a variety of physiological and pathological processes. Previous studies have focused more on respiratory-related diseases and tumors. However, recent studies have identified an important role for TMEM16A in cardiovascular diseases, especially in pulmonary hypertension. TMEM16A is expressed in both pulmonary artery smooth muscle cells and pulmonary artery endothelial cells and is involved in the development of pulmonary hypertension. This paper presents the structure and function of TMEM16A, the pathogenesis of pulmonary hypertension, and highlights the role and mechanism of TMEM16A in pulmonary hypertension, summarizing the controversies in this field and taking into account hypertension and portal hypertension, which have similar pathogenesis. It is hoped that the unique role of TMEM16A in pulmonary hypertension will be illustrated and provide ideas for research in this area.
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Affiliation(s)
- Ludong Yuan
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Yuting Tang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Leijing Yin
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Xiaofang Lin
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Zhengyang Luo
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Shuxin Wang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Jing Li
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Pengfei Liang
- Department of Burns and Plastic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bimei Jiang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China.
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7
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Little A, Medford A, O'Brien A, Childs J, Pan S, Machado J, Chakraborty S, Glaser S. Recent Advances in Intrahepatic Biliary Epithelial Heterogeneity. Semin Liver Dis 2023; 43:1-12. [PMID: 36522162 DOI: 10.1055/s-0042-1758833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Biliary epithelium (i.e., cholangiocytes) is a heterogeneous population of epithelial cells in the liver, which line small and large bile ducts and have individual responses and functions dependent on size and location in the biliary tract. We discuss the recent findings showing that the intrahepatic biliary tree is heterogeneous regarding (1) morphology and function, (2) hormone expression and signaling (3), response to injury, and (4) roles in liver regeneration. This review overviews the significant characteristics and differences of the small and large cholangiocytes. Briefly, it outlines the in vitro and in vivo models used in the heterogeneity evaluation. In conclusion, future studies addressing biliary heterogeneity's role in the pathogenesis of liver diseases characterized by ductular reaction may reveal novel therapeutic approaches.
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Affiliation(s)
- Ashleigh Little
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - Abigail Medford
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - April O'Brien
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - Jonathan Childs
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - Sharon Pan
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - Jolaine Machado
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - Sanjukta Chakraborty
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
| | - Shannon Glaser
- Department of Medical Physiology, Texas A&M University School of Medicine, Bryan, Texas
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8
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Shcheynikov N, Boggs K, Green A, Feranchak AP. Identification of the chloride channel, leucine-rich repeat-containing protein 8, subfamily a (LRRC8A), in mouse cholangiocytes. Hepatology 2022; 76:1248-1258. [PMID: 35445421 PMCID: PMC10126881 DOI: 10.1002/hep.32536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 04/18/2022] [Accepted: 04/19/2022] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIMS Chloride (Cl- ) channels in the apical membrane of biliary epithelial cells (BECs), also known as cholangiocytes, provide the driving force for biliary secretion. Although two Cl- channels have been identified on a molecular basis, the Cystic Fibrosis Transmembrane Conductance Regulator and Transmembrane Member 16A, a third Cl- channel with unique biophysical properties has been described. Leucine-Rich Repeat-Containing Protein 8, subfamily A (LRRC8A) is a newly identified protein capable of transporting Cl- in other epithelium in response to cell swelling. The aim of the present study was to determine if LRRC8A represents the volume-regulated anion channel in mouse BECs. APPROACH AND RESULTS Studies were performed in mouse small (MSC) and large (MLC) cholangiocytes. Membrane Cl- currents were measured by whole-cell patch-clamp techniques and cell volume measurements were performed by calcein-AM fluorescence. Exposure of either MSC or MLC to hypotonicity (190 mOsm) rapidly increased cell volume and activated Cl- currents. Currents exhibited outward rectification, time-dependent inactivation at positive membrane potentials, and reversal potential at 0 mV (ECl ). Removal of extracellular Cl- or specific pharmacological inhibition of LRRC8A abolished currents. LRRC8A was detected in both MSC and MLC by reverse transcription polymerase chain reaction and confirmed by western blot. Transfection with LRRC8A small interfering RNA decreased protein levels by >70% and abolished volume-stimulated Cl- currents. CONCLUSION These results demonstrate that LRRC8A is functionally present in mouse BECs, contributes to volume-activated Cl- secretion, and, therefore, may be a target to modulate bile formation in the treatment of cholestatic liver disorders.
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Affiliation(s)
- Nikolay Shcheynikov
- Department of Pediatrics, University of Pittsburgh Medical Center Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kristy Boggs
- Department of Pediatrics, University of Pittsburgh Medical Center Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anthony Green
- Tissue and Research Pathology Core, UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Andrew P Feranchak
- Department of Pediatrics, University of Pittsburgh Medical Center Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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9
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Wang W, Chen D, Wang J, Wen L. Cellular Homeostasis and Repair in the Biliary Tree. Semin Liver Dis 2022; 42:271-282. [PMID: 35672015 DOI: 10.1055/a-1869-7714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
During biliary tree homeostasis, BECs are largely in a quiescent state and their turnover is slow for maintaining normal tissue homeostasis. BTSCs continually replenish new BECs in the luminal surface of EHBDs. In response to various types of biliary injuries, distinct cellular sources, including HPCs, BTSCs, hepatocytes, and BECs, repair or regenerate the injured bile duct. BEC, biliary epithelial cell; BTSC, biliary tree stem/progenitor cell; EHBD, extrahepatic bile ducts; HPC, hepatic progenitor cell.The biliary tree comprises intrahepatic bile ducts and extrahepatic bile ducts lined with epithelial cells known as biliary epithelial cells (BECs). BECs are a common target of various cholangiopathies for which there is an unmet therapeutic need in clinical hepatology. The repair and regeneration of biliary tissue may potentially restore the normal architecture and function of the biliary tree. Hence, the repair and regeneration process in detail, including the replication of existing BECs, expansion and differentiation of the hepatic progenitor cells and biliary tree stem/progenitor cells, and transdifferentiation of the hepatocytes, should be understood. In this paper, we review biliary tree homeostasis, repair, and regeneration and discuss the feasibility of regenerative therapy strategies for cholangiopathy treatment.
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Affiliation(s)
- Wei Wang
- Department of Gastroenterology, Daping Hospital, Army Medical University, Chongqing, China
| | - Dongfeng Chen
- Department of Gastroenterology, Daping Hospital, Army Medical University, Chongqing, China
| | - Jun Wang
- Department of Gastroenterology, Daping Hospital, Army Medical University, Chongqing, China
| | - Liangzhi Wen
- Department of Gastroenterology, Daping Hospital, Army Medical University, Chongqing, China
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10
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Florentino RM, Li Q, Coard MC, Haep N, Motomura T, Diaz-Aragon R, Faccioli LAP, Amirneni S, Kocas-Kilicarslan ZN, Ostrowska A, Squires JE, Feranchak AP, Soto-Gutierrez A. Transmembrane channel activity in human hepatocytes and cholangiocytes derived from induced pluripotent stem cells. Hepatol Commun 2022; 6:1561-1573. [PMID: 35289126 PMCID: PMC9234678 DOI: 10.1002/hep4.1920] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/06/2022] [Accepted: 01/22/2022] [Indexed: 11/10/2022] Open
Abstract
The initial creation of human-induced pluripotent stem cells (iPSCs) set the foundation for the future of regenerative medicine. Human iPSCs can be differentiated into a variety of cell types in order to study normal and pathological molecular mechanisms. Currently, there are well-defined protocols for the differentiation, characterization, and establishment of functionality in human iPSC-derived hepatocytes (iHep) and iPSC-derived cholangiocytes (iCho). Electrophysiological study on chloride ion efflux channel activity in iHep and iCho cells has not been previously reported. We generated iHep and iCho cells and characterized them based on hepatocyte-specific and cholangiocyte-specific markers. The relevant transmembrane channels were selected: cystic fibrosis transmembrane conductance regulator, leucine rich repeat-containing 8 subunit A, and transmembrane member 16 subunit A. To measure the activity in these channels, we used whole-cell patch-clamp techniques with a standard intracellular and extracellular solution. Our iHep and iCho cells demonstrated definitive activity in the selected transmembrane channels, and this approach may become an important tool for investigating human liver biology of cholestatic diseases.
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Affiliation(s)
- Rodrigo M Florentino
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA.,Pittsburgh Liver Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Qin Li
- Department of PediatricsUniversity of Pittsburgh Medical CenterPittsburghPennsylvaniaUSA
| | - Michael C Coard
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Nils Haep
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Takashi Motomura
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Ricardo Diaz-Aragon
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Lanuza A P Faccioli
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Sriram Amirneni
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | | | - Alina Ostrowska
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA.,Pittsburgh Liver Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - James E Squires
- Pittsburgh Liver Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA.,Division of Gastroenterology, Hepatology, and NutritionUniversity of Pittsburgh Medical CenterPittsburghPennsylvaniaUSA
| | - Andrew P Feranchak
- Pittsburgh Liver Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA.,Department of PediatricsUniversity of Pittsburgh Medical CenterPittsburghPennsylvaniaUSA
| | - Alejandro Soto-Gutierrez
- Department of PathologyUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA.,Pittsburgh Liver Research CenterUniversity of PittsburghPittsburghPennsylvaniaUSA.,McGowan Institute for Regenerative MedicinePittsburghPennsylvaniaUSA
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11
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Zarei K, Thornell IM, Stoltz DA. Anion Transport Across Human Gallbladder Organoids and Monolayers. Front Physiol 2022; 13:882525. [PMID: 35685290 PMCID: PMC9171199 DOI: 10.3389/fphys.2022.882525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
Fluid and anion secretion are important functions of the biliary tract. It has been established that cAMP regulates Na+ absorption through NHE3. However, mechanisms of gallbladder anion transport are less defined. We created organoids and organoid-derived monolayers from human gallbladder tissue to measure organoid swelling and transepithelial electrophysiology. In our in vitro models, forskolin-stimulation caused organoid swelling and increased transepithelial anion transport. Full organoid swelling required Cl−while changes in short-circuit current were HCO3−-dependent. Organoids and monolayers from an individual homozygous for the cystic fibrosis-causing ΔF508 CFTR mutation had no apical expression of CFTR and minimal changes in transepithelial current and conductance with forskolin treatment. However, organoid swelling remained intact. Dilution potential studies revealed that forskolin treatment increased the paracellular permeability to anions relative to cations. These data suggest a novel paracellular contribution to forskolin-stimulated fluid transport across the gallbladder epithelium.
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Affiliation(s)
- Keyan Zarei
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States.,Department of Biomedical Engineering, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States
| | - Ian M Thornell
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States
| | - David A Stoltz
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States.,Department of Biomedical Engineering, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States.,Department of Molecular Physiology and Biophysics, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States.,Pappajohn Biomedical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine,, Iowa City, IA, United States
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12
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Ebihara L, Acharya P, Tong JJ. Mechanical Stress Modulates Calcium-Activated-Chloride Currents in Differentiating Lens Cells. Front Physiol 2022; 13:814651. [PMID: 35173630 PMCID: PMC8842795 DOI: 10.3389/fphys.2022.814651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 01/06/2022] [Indexed: 11/13/2022] Open
Abstract
During accommodation, the lens changes focus by altering its shape following contraction and relaxation of the ciliary muscle. At the cellular level, these changes in shape may be accompanied by fluid flow in and out of individual lens cells. We tested the hypothesis that some of this flow might be directly modulated by pressure-activated channels. In particular, we used the whole cell patch clamp technique to test whether calcium-activated-chloride channels (CaCCs) expressed in differentiating lens cells are activated by mechanical stimulation. Our results show that mechanical stress, produced by focally perfusing the lens cell at a constant rate, caused a significant increase in a chloride current that could be fully reversed by stopping perfusion. The time course of activation and recovery from activation of the flow-induced current occurred rapidly over a time frame similar to that of accommodation. The flow-induced current could be inhibited by the TMEM16A specific CaCC blocker, Ani9, suggesting that the affected current was predominantly due to TMEM16A chloride channels. The mechanism of action of mechanical stress did not appear to involve calcium influx through other mechanosensitive ion channels since removal of calcium from the bath solution failed to block the flow-induced chloride current. In conclusion, our results suggest that CaCCs in the lens can be rapidly and reversibly modulated by mechanical stress, consistent with their participation in regulation of volume in this organ.
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Affiliation(s)
- Lisa Ebihara
- Center of Proteomics and Molecular Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
- Discipline of Physiology and Biophysics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
- *Correspondence: Lisa Ebihara,
| | - Pooja Acharya
- Center of Proteomics and Molecular Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
| | - Jun-Jie Tong
- Center of Proteomics and Molecular Therapeutics, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States
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13
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Chen B, Jefferson DM, Cho WK. Impaired Regulatory Volume Decrease and Characterization of Underlying Volume-Activated Currents in Cystic Fibrosis Human Cholangiocyte Cell Line. J Membr Biol 2022; 255:261-276. [DOI: 10.1007/s00232-022-00216-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/11/2022] [Indexed: 11/29/2022]
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14
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Polymodal Control of TMEM16x Channels and Scramblases. Int J Mol Sci 2022; 23:ijms23031580. [PMID: 35163502 PMCID: PMC8835819 DOI: 10.3390/ijms23031580] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
The TMEM16A/anoctamin-1 calcium-activated chloride channel (CaCC) contributes to a range of vital functions, such as the control of vascular tone and epithelial ion transport. The channel is a founding member of a family of 10 proteins (TMEM16x) with varied functions; some members (i.e., TMEM16A and TMEM16B) serve as CaCCs, while others are lipid scramblases, combine channel and scramblase function, or perform additional cellular roles. TMEM16x proteins are typically activated by agonist-induced Ca2+ release evoked by Gq-protein-coupled receptor (GqPCR) activation; thus, TMEM16x proteins link Ca2+-signalling with cell electrical activity and/or lipid transport. Recent studies demonstrate that a range of other cellular factors—including plasmalemmal lipids, pH, hypoxia, ATP and auxiliary proteins—also control the activity of the TMEM16A channel and its paralogues, suggesting that the TMEM16x proteins are effectively polymodal sensors of cellular homeostasis. Here, we review the molecular pathophysiology, structural biology, and mechanisms of regulation of TMEM16x proteins by multiple cellular factors.
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15
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Hawn MB, Akin E, Hartzell H, Greenwood IA, Leblanc N. Molecular mechanisms of activation and regulation of ANO1-Encoded Ca 2+-Activated Cl - channels. Channels (Austin) 2021; 15:569-603. [PMID: 34488544 PMCID: PMC8480199 DOI: 10.1080/19336950.2021.1975411] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 08/29/2021] [Indexed: 01/13/2023] Open
Abstract
Ca2+-activated Cl- channels (CaCCs) perform a multitude of functions including the control of cell excitability, regulation of cell volume and ionic homeostasis, exocrine and endocrine secretion, fertilization, amplification of olfactory sensory function, and control of smooth muscle cell contractility. CaCCs are the translated products of two members (ANO1 and ANO2, also known as TMEM16A and TMEM16B) of the Anoctamin family of genes comprising ten paralogs. This review focuses on recent progress in understanding the molecular mechanisms involved in the regulation of ANO1 by cytoplasmic Ca2+, post-translational modifications, and how the channel protein interacts with membrane lipids and protein partners. After first reviewing the basic properties of native CaCCs, we then present a brief historical perspective highlighting controversies about their molecular identity in native cells. This is followed by a summary of the fundamental biophysical and structural properties of ANO1. We specifically address whether the channel is directly activated by internal Ca2+ or indirectly through the intervention of the Ca2+-binding protein Calmodulin (CaM), and the structural domains responsible for Ca2+- and voltage-dependent gating. We then review the regulation of ANO1 by internal ATP, Calmodulin-dependent protein kinase II-(CaMKII)-mediated phosphorylation and phosphatase activity, membrane lipids such as the phospholipid phosphatidyl-(4,5)-bisphosphate (PIP2), free fatty acids and cholesterol, and the cytoskeleton. The article ends with a survey of physical and functional interactions of ANO1 with other membrane proteins such as CLCA1/2, inositol trisphosphate and ryanodine receptors in the endoplasmic reticulum, several members of the TRP channel family, and the ancillary Κ+ channel β subunits KCNE1/5.
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Affiliation(s)
- M. B. Hawn
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - E. Akin
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - H.C. Hartzell
- Department of Cell Biology, Emory University School of Medicine, USA
| | - I. A. Greenwood
- Department of Vascular Pharmacology, St. George’s University of London, UK
| | - N. Leblanc
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
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16
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Bai W, Liu M, Xiao Q. The diverse roles of TMEM16A Ca 2+-activated Cl - channels in inflammation. J Adv Res 2021; 33:53-68. [PMID: 34603778 PMCID: PMC8463915 DOI: 10.1016/j.jare.2021.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/17/2020] [Accepted: 01/24/2021] [Indexed: 12/14/2022] Open
Abstract
Background Transmembrane protein 16A (TMEM16A) Ca2+-activated Cl- channels have diverse physiological functions, such as epithelial secretion of Cl- and fluid and sensation of pain. Recent studies have demonstrated that TMEM16A contributes to the pathogenesis of infectious and non-infectious inflammatory diseases. However, the role of TMEM16A in inflammation has not been clearly elucidated. Aim of review In this review, we aimed to provide comprehensive information regarding the roles of TMEM16A in inflammation by summarizing the mechanisms underlying TMEM16A expression and activation under inflammatory conditions, in addition to exploring the diverse inflammatory signaling pathways activated by TMEM16A. This review attempts to develop the idea that TMEM16A plays a diverse role in inflammatory processes and contributes to inflammatory diseases in a cellular environment-dependent manner. Key scientific concepts of review Multiple inflammatory mediators, including cytokines (e.g., interleukin (IL)-4, IL-13, IL-6), histamine, bradykinin, and ATP/UTP, as well as bacterial and viral infections, promote TMEM16A expression and/or activity under inflammatory conditions. In addition, TMEM16A activates diverse inflammatory signaling pathways, including the IP3R-mediated Ca2+ signaling pathway, the NF-κB signaling pathway, and the ERK signaling pathway, and contributes to the pathogenesis of many inflammatory diseases. These diseases include airway inflammatory diseases, lipopolysaccharide-induced intestinal epithelial barrier dysfunction, acute pancreatitis, and steatohepatitis. TMEM16A also plays multiple roles in inflammatory processes by increasing vascular permeability and leukocyte adhesion, promoting inflammatory cytokine release, and sensing inflammation-induced pain. Furthermore, TMEM16A plays its diverse pathological roles in different inflammatory diseases depending on the disease severity, proliferating status of the cells, and its interacting partners. We herein propose cellular environment-dependent mechanisms that explain the diverse roles of TMEM16A in inflammation.
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Affiliation(s)
- Weiliang Bai
- Department of Otolaryngology Head and Neck Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Mei Liu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
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17
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Wu N, Baiocchi L, Zhou T, Kennedy L, Ceci L, Meng F, Sato K, Wu C, Ekser B, Kyritsi K, Kundu D, Chen L, Meadows V, Franchitto A, Alvaro D, Onori P, Gaudio E, Lenci I, Francis H, Glaser S, Alpinis G. Functional Role of the Secretin/Secretin Receptor Signaling During Cholestatic Liver Injury. Hepatology 2020; 72:2219-2227. [PMID: 32737904 PMCID: PMC8957864 DOI: 10.1002/hep.31484] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/02/2020] [Indexed: 12/19/2022]
Abstract
The gastrointestinal peptide, secretin (Sct) is an important homeostatic regulator of pancreatic and liver secretory function. With regard to the liver, discoveries have been made, in the last decades, indicating a key role for the secretin/secretin receptor axis during normal or cholestatic conditions. Since large cholangiocytes are the only cells to express secretin receptor in the liver, research on secretin also expanded our knowledge on biliary epithelia. In this review we examined in detail the role of the secretin/secretin receptor axis, not only on biliary secretion, but also on cholangiocyte proliferation and senescence, as well as in prompting fibrotic processes involving biliary epithelia. Relevant data on human chronic cholestatic liver diseases, such as primary biliary cholangitis or primary sclerosing cholangitis, and obtained in animal models mimicking the diseases or in correlative studies on human are also reported. The aim of this review is to provide an update on the progress regarding the interactions between secretin and the biliary epithelia in normal and pathological conditions, underlining the aspects that suggests modulation of secretin pathway as a possible therapeutic approach for chronic cholestatic human liver disease.
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Affiliation(s)
- Nan Wu
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Leonardo Baiocchi
- Liver Unit, Department of Medicine, University of Rome “Tor Vergata”, Rome, Italy
| | - Tianhao Zhou
- Department of Medical Physiology, Texas A&M University, Bryan, TX
| | - Lindsey Kennedy
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Ludovica Ceci
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Fanyin Meng
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN,Richard L. Roudebush VA Medical Center, Indianapolis, IN
| | - Keisaku Sato
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Chaodong Wu
- Department of Nutrition, Texas A&M University, College Station, TX
| | - Burcin Ekser
- Division of Transplant Surgery, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN
| | - Konstantina Kyritsi
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Debjyoti Kundu
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Lixian Chen
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | - Vik Meadows
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN
| | | | - Domenico Alvaro
- Department of Internal Medicine and Medical Specialties and Sapienza University of Rome, Rome, Italy
| | - Paolo Onori
- Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, Rome, Italy
| | - Eugenio Gaudio
- Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, Rome, Italy
| | - Ilaria Lenci
- Liver Unit, Department of Medicine, University of Rome “Tor Vergata”, Rome, Italy
| | - Heather Francis
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN,Richard L. Roudebush VA Medical Center, Indianapolis, IN
| | - Shannon Glaser
- Department of Medical Physiology, Texas A&M University, Bryan, TX
| | - Gianfranco Alpinis
- Hepatology and Gastroenterology, Medicine, Indiana University, Indianapolis, IN,Richard L. Roudebush VA Medical Center, Indianapolis, IN
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18
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Zarei K, Stroik MR, Gansemer ND, Thurman AL, Ostedgaard LS, Ernst SE, Thornell IM, Powers LS, Pezzulo AA, Meyerholz DK, Stoltz DA. Early pathogenesis of cystic fibrosis gallbladder disease in a porcine model. J Transl Med 2020; 100:1388-1399. [PMID: 32719544 PMCID: PMC7578062 DOI: 10.1038/s41374-020-0474-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 12/13/2022] Open
Abstract
Hepatobiliary disease causes significant morbidity in people with cystic fibrosis (CF), yet this problem remains understudied. We previously found that newborn CF pigs have microgallbladders with significant luminal obstruction in the absence of infection and consistent inflammation. In this study, we sought to better understand the early pathogenesis of CF pig gallbladder disease. We hypothesized that loss of CFTR would impair gallbladder epithelium anion/liquid secretion and increase mucin production. CFTR was expressed apically in non-CF pig gallbladder epithelium but was absent in CF. CF pig gallbladders lacked cAMP-stimulated anion transport. Using a novel gallbladder epithelial organoid model, we found that Cl- or HCO3- was sufficient for non-CF organoid swelling. This response was absent for non-CF organoids in Cl-/HCO3--free conditions and in CF. Single-cell RNA-sequencing revealed a single epithelial cell type in non-CF gallbladders that coexpressed CFTR, MUC5AC, and MUC5B. Despite CF gallbladders having increased luminal MUC5AC and MUC5B accumulation, there was no significant difference in the epithelial expression of gel-forming mucins between non-CF and CF pig gallbladders. In conclusion, these data suggest that loss of CFTR-mediated anion transport and fluid secretion contribute to microgallbladder development and luminal mucus accumulation in CF.
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Affiliation(s)
- Keyan Zarei
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA, 52242, USA
| | - Mallory R Stroik
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Nick D Gansemer
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Andrew L Thurman
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Lynda S Ostedgaard
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Sarah E Ernst
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Ian M Thornell
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Linda S Powers
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Alejandro A Pezzulo
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - David K Meyerholz
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
| | - David A Stoltz
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA, 52242, USA.
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
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19
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Brevini T, Tysoe OC, Sampaziotis F. Tissue engineering of the biliary tract and modelling of cholestatic disorders. J Hepatol 2020; 73:918-932. [PMID: 32535061 DOI: 10.1016/j.jhep.2020.05.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 04/20/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022]
Abstract
Our insight into the pathogenesis of cholestatic liver disease remains limited, partly owing to challenges in capturing the multitude of factors that contribute to disease pathogenesis in vitro. Tissue engineering could address this challenge by combining cells, materials and fabrication strategies into dynamic modelling platforms, recapitulating the multifaceted aetiology of cholangiopathies. Herein, we review the advantages and limitations of platforms for bioengineering the biliary tree, looking at how these can be applied to model biliary disorders, as well as exploring future directions for the field.
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Affiliation(s)
- Teresa Brevini
- Wellcome Trust-Medical Research Council Stem Cell Institute, Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Olivia C Tysoe
- Wellcome Trust-Medical Research Council Stem Cell Institute, Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK; Department of Surgery, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge, UK
| | - Fotios Sampaziotis
- Wellcome Trust-Medical Research Council Stem Cell Institute, Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK; Department of Hepatology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Department of Medicine, University of Cambridge, Cambridge, UK.
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20
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Shin DH, Kim M, Kim Y, Jun I, Jung J, Nam JH, Cheng MH, Lee MG. Bicarbonate permeation through anion channels: its role in health and disease. Pflugers Arch 2020; 472:1003-1018. [PMID: 32621085 DOI: 10.1007/s00424-020-02425-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/19/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022]
Abstract
Many anion channels, frequently referred as Cl- channels, are permeable to different anions in addition to Cl-. As the second-most abundant anion in the human body, HCO3- permeation via anion channels has many important physiological roles. In addition to its classical role as an intracellular pH regulator, HCO3- also controls the activity and stability of dissolved proteins in bodily fluids such as saliva, pancreatic juice, intestinal fluid, and airway surface liquid. Moreover, HCO3- permeation through these channels affects membrane potentials that are the driving forces for transmembrane transport of solutes and water in epithelia and affect neuronal excitability in nervous tissue. Consequently, aberrant HCO3- transport via anion channels causes a number of human diseases in respiratory, gastrointestinal, genitourinary, and neuronal systems. Notably, recent studies have shown that the HCO3- permeabilities of several anion channels are not fixed and can be altered by cellular stimuli, findings which may have both physiological and pathophysiological significance. In this review, we summarize recent progress in understanding the molecular mechanisms and the physiological roles of HCO3- permeation through anion channels. We hope that the present discussions can stimulate further research into this very important topic, which will provide the basis for human disorders associated with aberrant HCO3- transport.
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Affiliation(s)
- Dong Hoon Shin
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Minjae Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Yonjung Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Ikhyun Jun
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Jinsei Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Kyungju, 780-714, Republic of Korea
| | - Mary Hongying Cheng
- Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea.
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21
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Nejak-Bowen K. If It Looks Like a Duct and Acts Like a Duct: On the Role of Reprogrammed Hepatocytes in Cholangiopathies. Gene Expr 2020; 20:19-23. [PMID: 31439080 PMCID: PMC7284107 DOI: 10.3727/105221619x15664105014956] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cholangiopathies are chronic, progressive diseases of the biliary tree, and can be either acquired or genetic. The primary target is the cholangiocyte (CC), the cell type lining the bile duct that is responsible for bile modification and transport. Despite advances in our understanding and diagnosis of these diseases in recent years, there are no proven therapeutic treatments for the majority of the cholangiopathies, and liver transplantation is the only life-extending treatment option for patients with end-stage cholestatic liver disease. One potential therapeutic strategy is to facilitate endogenous repair of the biliary system, which may alleviate intrahepatic cholestasis caused by these diseases. During biliary injury, hepatocytes (HC) are known to alter their phenotype and acquire CC-like features, a process known as cellular reprogramming. This brief review discusses the potential ways in which reprogrammed HC may contribute to biliary repair, thereby restoring bile flow and reducing the severity of cholangiopathies. Some of these include modifying bile to reduce toxicity, serving as a source of de novo CC to repair the biliary epithelium, or creating new channels to facilitate bile flow.
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Affiliation(s)
- Kari Nejak-Bowen
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA
- Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, USA
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22
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Guo J, Liu X, Zhang T, Lin X, Hong Y, Yu J, Wu Q, Zhang F, Wu Q, Shang J, Lv X, Ou J, Zhou J, Pang R, Tang B, Liang S. Hepatocyte TMEM16A Deletion Retards NAFLD Progression by Ameliorating Hepatic Glucose Metabolic Disorder. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1903657. [PMID: 32440483 PMCID: PMC7237841 DOI: 10.1002/advs.201903657] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/22/2020] [Accepted: 02/27/2020] [Indexed: 06/11/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most prevalent form of chronic liver disease, and the mechanisms underpinning its pathogenesis have not been completely established. Transmembrane member 16A (TMEM16A), a component of the Ca2+-activated chloride channel (CaCC), has recently been implicated in metabolic events. Herein, TMEM16A is shown to be responsible for CaCC activation in hepatocytes and is increased in liver tissues of mice and patients with NAFLD. Hepatocyte-specific ablation of TMEM16A in mice ameliorates high-fat diet-induced obesity, hepatic glucose metabolic disorder, steatosis, insulin resistance, and inflammation. In contrast, hepatocyte-specific TMEM16A transgenic mice exhibit the opposite phenotype. Mechanistically, hepatocyte TMEM16A interacts with vesicle-associated membrane protein 3 (VAMP3) to induce its degradation, suppressing the formation of the VAMP3/syntaxin 4 and VAMP3/synaptosome-associated protein 23 complexes. This leads to the impairment of hepatic glucose transporter 2 (GLUT2) translocation and glucose uptake. Notably, VAMP3 overexpression restrains the functions of hepatocyte TMEM16A in blocking GLUT2 translocation and promoting lipid deposition, insulin resistance, and inflammation. In contrast, VAMP3 knockdown reverses the beneficial effects of TMEM16A downregulation. This study demonstrates a role for TMEM16A in NAFLD and suggests that inhibition of hepatic TMEM16A or disruption of TMEM16A/VAMP3 interaction may provide a new potential therapeutic strategy for NAFLD.
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Affiliation(s)
- Jia‐Wei Guo
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Xiu Liu
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Ting‐Ting Zhang
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Xiao‐Chun Lin
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Yu Hong
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Jie Yu
- Department of Gastrointestinal SurgeryThe First Affiliated HospitalSun Yat‐Sen UniversityGuangzhou510080China
| | - Qin‐Yan Wu
- Department of GastroenterologyThe First People's Hospital of FoshanFoshan528000China
| | - Fei‐Ran Zhang
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Qian‐Qian Wu
- Key Laboratory of Metabolic Cardiovascular Diseases Research of National Health CommissionNingxia Medical UniversityYinchuan750004China
| | - Jin‐Yan Shang
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Xiao‐Fei Lv
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Jing‐Song Ou
- Division of Cardiac SurgeryThe Key Laboratory of Assisted CirculationMinistry of HealthThe First Affiliated HospitalSun Yat‐Sen UniversityGuangzhou510080China
- National‐Guangdong Joint Engineering Laboratory for Diagnosis and Treatment of Vascular DiseasesThe First Affiliated HospitalSun Yat‐Sen UniversityGuangzhou510080China
| | - Jia‐Guo Zhou
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
- Program of Kidney and Cardiovascular DiseaseThe Fifth Affiliated HospitalSun Yat‐Sen UniversityGuangzhou510080China
- Department of CardiologySun Yat‐Sen Memorial HospitalSun Yat‐Sen UniversityGuangzhou510120China
- Guangdong Province Key Laboratory of Brain Function and DiseaseZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Rui‐Ping Pang
- Guangdong Province Key Laboratory of Brain Function and DiseaseZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
- Department of PhysiologyPain Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
| | - Bao‐Dong Tang
- Department of GastroenterologyThe First Affiliated HospitalSun Yat‐Sen UniversityGuangzhou510080China
| | - Si‐Jia Liang
- Department of PharmacologyCardiac and Cerebral Vascular Research CenterZhongshan School of MedicineSun Yat‐Sen UniversityGuangzhou510080China
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Dutta AK, Boggs K, Khimji AK, Getachew Y, Wang Y, Kresge C, Rockey DC, Feranchak AP. Signaling through the interleukin-4 and interleukin-13 receptor complexes regulates cholangiocyte TMEM16A expression and biliary secretion. Am J Physiol Gastrointest Liver Physiol 2020; 318:G763-G771. [PMID: 32090602 PMCID: PMC7191463 DOI: 10.1152/ajpgi.00219.2019] [Citation(s) in RCA: 9] [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
TMEM16A is a Ca2+-activated Cl- channel in the apical membrane of biliary epithelial cells, known as cholangiocytes, which contributes importantly to ductular bile formation. Whereas cholangiocyte TMEM16A activity is regulated by extracellular ATP-binding membrane purinergic receptors, channel expression is regulated by interleukin-4 (IL-4) through an unknown mechanism. Therefore, the aim of the present study was to identify the signaling pathways involved in TMEM16A expression and cholangiocyte secretion. Studies were performed in polarized normal rat cholangiocyte monolayers, human Mz-Cha-1 biliary cells, and cholangiocytes isolated from murine liver tissue. The results demonstrate that all the biliary models expressed the IL-4Rα/IL-13Rα1 receptor complex. Incubation of cholangiocytes with either IL-13 or IL-4 increased the expression of TMEM16A protein, which was associated with an increase in the magnitude of Ca2+-activated Cl- currents in response to ATP in single cells and the short-circuit current response in polarized monolayers. The IL-4- and IL-13-mediated increase in TMEM16A expression was also associated with an increase in STAT6 phosphorylation. Specific inhibition of JAK-3 inhibited the increase in TMEM16A expression and the IL-4-mediated increase in ATP-stimulated currents, whereas inhibition of STAT6 inhibited both IL-4- and IL-13-mediated increases in TMEM16A expression and ATP-stimulated secretion. These studies demonstrate that the cytokines IL-13 and IL-4 regulate the expression and function of biliary TMEM16A channels through a signaling pathway involving STAT6. Identification of this regulatory pathway provides new insight into biliary secretion and suggests new targets to enhance bile formation in the treatment of cholestatic liver disorders.NEW & NOTEWORTHY The Ca2+-activated Cl- channel transmembrane member 16A (TMEM16A) has emerged as an important regulator of biliary secretion and hence, ductular bile formation. The present studies represent the initial description of the regulation of TMEM16A expression in biliary epithelium. Identification of this regulatory pathway involving the IL-4 and IL-13 receptor complex and JAK-3 and STAT-6 signaling provides new insight into biliary secretion and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.
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Affiliation(s)
- Amal K. Dutta
- 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Kristy Boggs
- 4Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Al-karim Khimji
- 2Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yonas Getachew
- 2Department of Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Youxue Wang
- 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Charles Kresge
- 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Don C. Rockey
- 3Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Andrew P. Feranchak
- 4Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
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24
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Li Q, Kresge C, Boggs K, Scott J, Feranchak A. Mechanosensor transient receptor potential vanilloid member 4 (TRPV4) regulates mouse cholangiocyte secretion and bile formation. Am J Physiol Gastrointest Liver Physiol 2020; 318:G277-G287. [PMID: 31760763 PMCID: PMC7052575 DOI: 10.1152/ajpgi.00176.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mechanosensitive signaling has emerged as a mechanism for the regulation of cholangiocyte transport and bile formation. The mechanical effect of fluid-flow, or shear, at the apical membrane of cholangiocytes regulates secretion through a process involving increases in [Ca2+]i and activation of Ca2+-activated Cl- channels. However, the initiating steps translating shear force to increases in intracellular calcium concentration ([Ca2+]i) are unknown. Transient receptor potential vanilloid member 4 (TRPV4), a nonselective cation channel present in the apical membrane of cholangiocytes, has been proposed as a potential mechanosensor. The aim of the present studies was to determine the potential role of TRPV4 in initiating mechanosensitive signaling in response to fluid-flow in cholangiocytes. TRPV4 expression was confirmed in both small and large mouse cholangiocytes. Exposure of cells to either fluid flow or specific TRPV4 pharmacological agonists rapidly increased both [Ca2+]i and membrane cation currents. Both flow- and agonist-stimulated currents displayed identical biophysical properties and were inhibited in the presence of TRPV4 antagonists or in cells after transfection with TRPV4 small interfering RNA. Transfection of mouse cholangiocytes with a TRPV4-enhanced green fluorescent protein construct increased the expression of TRPV4 and the magnitude of flow-stimulated currents. A specific TRPV4 agonist significantly increased the biliary concentration of ATP and bile flow in live mice when administered intravenously and increased ATP release from cholangiocyte monolayers when applied exogenously. The findings are consistent with a model in which activation of cholangiocyte TRPV4 translates shear force into an acute rise in membrane cation permeability, [Ca2+]i, ATP release, and bile flow. Understanding the role of mechanosensitive transport pathways may provide novel insights to modulate bile flow for the treatment of cholestatic liver disorders.NEW & NOTEWORTHY These studies functionally characterize TRPV4 as a mechanosensitive channel in mouse cholangiocytes. By mediating a rapid rise in intracellular Ca2+, necessary for Ca2+-dependent secretion, TRPV4 represents a mechanosensor responsible for translating fluid flow into intracellular signaling and biliary secretion. Furthermore, intravenous infusion of a specific TRPV4 agonist increases bile flow in live mice. Understanding the role of TRPV4 in mechanosensitive transport pathways may provide novel insights to modulate bile flow during cholestasis.
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Affiliation(s)
- Qin Li
- 1Department of Physiology, Jianghan University School of Medicine, Wuhan, China,3Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Charles Kresge
- 2Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Kristy Boggs
- 3Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Julie Scott
- 3Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Andrew Feranchak
- 3Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
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25
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Wang Q, Bai L, Luo S, Wang T, Yang F, Xia J, Wang H, Ma K, Liu M, Wu S, Wang H, Guo S, Sun X, Xiao Q. TMEM16A Ca 2+-activated Cl - channel inhibition ameliorates acute pancreatitis via the IP 3R/Ca 2+/NFκB/IL-6 signaling pathway. J Adv Res 2020; 23:25-35. [PMID: 32071789 PMCID: PMC7016042 DOI: 10.1016/j.jare.2020.01.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/14/2020] [Accepted: 01/18/2020] [Indexed: 02/08/2023] Open
Abstract
TMEM16A Ca2+-activated Cl- channels are expressed in pancreatic acinar cells and participate in inflammation-associated diseases. Whether TMEM16A contributes to the pathogenesis of acute pancreatitis (AP) remains unknown. Here, we found that increased TMEM16A expression in the pancreatic tissue was correlated with the interleukin-6 (IL-6) level in the pancreatic tissue and in the serum of a cerulein-induced AP mouse model. IL-6 treatment promoted TMEM16A expression in AR42J pancreatic acinar cells via the IL-6 receptor (IL-6R)/signal transducers and activators of transcription 3 (STAT3) signaling pathway. In addition, TMEM16A was co-immunoprecipitated with the inositol 1,4,5-trisphosphate receptor (IP3R) and was activated by IP3R-mediated Ca2+ release. TMEM16A inhibition reduced the IP3R-mediated Ca2+ release induced by cerulein. Furthermore, TMEM16A overexpression activated nuclear factor-κB (NFκB) and increased IL-6 release by increasing intracellular Ca2+. TMEM16A knockdown by shRNAs reduced the cerulein-induced NFκB activation by Ca2+. TMEM16A inhibitors inhibited NFκB activation by decreasing channel activity and reducing TMEM16A protein levels in AR42J cells, and it ameliorated pancreatic damage in cerulein-induced AP mice. This study identifies a novel mechanism underlying the pathogenesis of AP by which IL-6 promotes TMEM16A expression via IL-6R/STAT3 signaling activation, and TMEM16A overexpression increases IL-6 secretion via IP3R/Ca2+/NFκB signaling activation in pancreatic acinar cells. TMEM16A inhibition may be a new potential strategy for treating AP.
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Key Words
- AP, acute pancreatitis
- Acute pancreatitis
- BAPTA-AM, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid-acetyloxymethyl ester
- CCK, cholesystokinin
- CFBE, cystic fibrosis bronchial epithelial
- CaCCinh-A01, Ca2+-activated Cl− channel inhibitor-A01
- EDTA, ethylenediaminetetraacetic acid
- EGF, epidermal growth factor
- EGFP, green fluorescent protein
- EGFR, epidermal growth factor receptor
- EGTA, ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid
- ELISA, enzyme-linked immunosorbent assay
- ER, endoplasmic reticulum
- FBS, fetal bovine serum
- HEPES, N-2-hydroxyethil-piperazine-N'-2-ethanesulfonic acid
- IL-6, interleukin 6
- IL-6R, interleukin 6 receptor
- IP3R, inositol 1,4,5-trisphosphate receptor
- Inositol 1,4,5-trisphosphate receptor
- Interleukin-6
- NFκB
- NFκB, nuclear factor-κB
- NMDG, N-methyl-D-glucamine
- NP-40, Nonidet P-40
- PACs, pancreatic acinar cells
- RIPA, radio immunoprecipitation assay
- SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis
- STAT3, signal transducers and activators of transcription 3
- T16Ainh-A01, TMEM16A inhibitor-A01
- TMEM16A
- Tris, tris(hydroxymethyl)aminomethane
- WT, wild type
- shRNAs, short hairpin RNAs
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Affiliation(s)
- Qinghua Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China.,Department of Experimental Center, The Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang 110032, China
| | - Lichuan Bai
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shuya Luo
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Tianyu Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Fan Yang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Jialin Xia
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Hui Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Ke Ma
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Mei Liu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shuwei Wu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Huijie Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Shibin Guo
- Department of Gastroenterological Endoscopy, the First Affiliated Hospital of Dalian Medical University, Dalian 116011, China
| | - Xiaohong Sun
- Department of Neurology, The Fourth Affiliated Hospital of China Medical University, Shenyang 110032, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
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26
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Fiorotto R, Strazzabosco M. Pathophysiology of Cystic Fibrosis Liver Disease: A Channelopathy Leading to Alterations in Innate Immunity and in Microbiota. Cell Mol Gastroenterol Hepatol 2019; 8:197-207. [PMID: 31075352 PMCID: PMC6664222 DOI: 10.1016/j.jcmgh.2019.04.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 04/24/2019] [Accepted: 04/24/2019] [Indexed: 12/12/2022]
Abstract
Cystic fibrosis (CF) is a monogenic disease caused by mutation of Cftr. CF-associated liver disease (CFLD) is a common nonpulmonary cause of mortality in CF and accounts for approximately 2.5%-5% of overall CF mortality. The peak of the disease is in the pediatric population, but a second wave of liver disease in CF adults has been reported in the past decade in association with an increase in the life expectancy of these patients. New drugs are available to correct the basic defect in CF but their efficacy in CFLD is not known. The cystic fibrosis transmembrane conductance regulator, expressed in the apical membrane of cholangiocytes, is a major determinant for bile secretion and CFLD classically has been considered a channelopathy. However, the recent findings of the cystic fibrosis transmembrane conductance regulator as a regulator of epithelial innate immunity and the possible influence of the intestinal disease with an altered microbiota on the liver complication have opened new mechanistic insights on the pathogenesis of CFLD. This review provides an overview of the current understanding of the pathophysiology of the disease and discusses a potential target for intervention.
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Affiliation(s)
- Romina Fiorotto
- Correspondence Address correspondence to: Romina Fiorotto, PhD, Section of Digestive Diseases, Yale Liver Center, Yale School of Medicine, 333 Cedar Street, 1080-LMP, PO Box 208019, New Haven, Connecticut 06520. fax: (203) 785-7273.
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27
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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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28
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Wang R, Lu Y, Cicha MZ, Singh MV, Benson CJ, Madden CJ, Chapleau MW, Abboud FM. TMEM16B determines cholecystokinin sensitivity of intestinal vagal afferents of nodose neurons. JCI Insight 2019; 4:122058. [PMID: 30843875 DOI: 10.1172/jci.insight.122058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 01/17/2019] [Indexed: 12/11/2022] Open
Abstract
The satiety effects and metabolic actions of cholecystokinin (CCK) have been recognized as potential therapeutic targets in obesity for decades. We identified a potentially novel Ca2+-activated chloride (Cl-) current (CaCC) that is induced by CCK in intestinal vagal afferents of nodose neurons. The CaCC subunit Anoctamin 2 (Ano2/TMEM16B) is the dominant contributor to this current. Its expression is reduced, as is CCK current activity in obese mice on a high-fat diet (HFD). Reduced expression of TMEM16B in the heterozygote KO of the channel in sensory neurons results in an obese phenotype with a loss of CCK sensitivity in intestinal nodose neurons, a loss of CCK-induced satiety, and metabolic changes, including decreased energy expenditure. The effect on energy expenditure is further supported by evidence in rats showing that CCK enhances sympathetic nerve activity and thermogenesis in brown adipose tissue, and these effects are abrogated by a HFD and vagotomy. Our findings reveal that Ano2/TMEM16B is a Ca2+-activated chloride channel in vagal afferents of nodose neurons and a major determinant of CCK-induced satiety, body weight control, and energy expenditure, making it a potential therapeutic target in obesity.
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Affiliation(s)
- Runping Wang
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Yongjun Lu
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Michael Z Cicha
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Madhu V Singh
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and
| | - Christopher J Benson
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Christopher J Madden
- Department of Neurological Surgery, Oregon Health & Science University, Portland, Oregon, USA
| | - Mark W Chapleau
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - François M Abboud
- Department of Internal Medicine.,Abboud Cardiovascular Research Center, and.,Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
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29
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Mazzone A, Gibbons SJ, Eisenman ST, Strege PR, Zheng T, D'Amato M, Ordog T, Fernandez-Zapico ME, Farrugia G. Direct repression of anoctamin 1 ( ANO1) gene transcription by Gli proteins. FASEB J 2019; 33:6632-6642. [PMID: 30802137 DOI: 10.1096/fj.201802373r] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Ca2+-activated Cl- channel, anoctamin 1 (Ano1, also known as transmembrane protein 16A) contributes to intestinal pacemaking, fluid secretion, cellular excitability, and tissue development. The human ANO1 promoter contains binding sites for the glioma-associated oncogene (Gli) proteins. We investigated regulation of ANO1 transcription by Gli. ANO1 promoter activity was determined using a luciferase reporter system. Binding and functional effects of Glis on ANO1 transcription and expression were demonstrated by chromatin immunoprecipitation, small interfering RNA knockdown, PCR, immunolabeling, and recordings of Ca2+-activated Cl- currents in human embryonic kidney 293 (HEK293) cells. Results from previous genome-wide association studies were used to test ANO1 promoter polymorphisms for association with disease. Gli1 and Gli2 bound to the promoter and repressed ANO1 transcription. Repression depended on Gli binding to a site close to the ANO1 transcriptional start site. Mutation of this site prevented Gli binding and transcriptional repression. Knockdown of Gli expression and inhibition of Gli activity increased expression of ANO1 RNA and Ca2+-activated Cl- currents in HEK293 cells. A single-nucleotide polymorphism prevented Gli binding and showed association with irritable bowel syndrome. We conclude that Gli1 and Gli2 repress ANO1 by a novel mechanism that is independent of Gli cleavage and that has a role in gastrointestinal function.-Mazzone, A., Gibbons, S. J., Eisenman, S. T., Strege, P. R., Zheng, T., D'Amato, M., Ordog, T., Fernandez-Zapico, M. E., Farrugia, G. Direct repression of anoctamin 1 (ANO1) gene transcription by Gli proteins.
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Affiliation(s)
- Amelia Mazzone
- Enteric NeuroSciences, Mayo Clinic, Rochester, Minnesota, USA
| | - Simon J Gibbons
- Enteric NeuroSciences, Mayo Clinic, Rochester, Minnesota, USA
| | - Seth T Eisenman
- Enteric NeuroSciences, Mayo Clinic, Rochester, Minnesota, USA
| | - Peter R Strege
- Enteric NeuroSciences, Mayo Clinic, Rochester, Minnesota, USA
| | - Tenghao Zheng
- Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mauro D'Amato
- Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Biodonostia Health Research Institute, San Sebastián, Spain.,Ikerbasque-Basque Science Foundation, San Sebastián, Spain
| | - Tamas Ordog
- Enteric NeuroSciences, Mayo Clinic, Rochester, Minnesota, USA
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30
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Rodrigues MA, Gomes DA, Nathanson MH. Calcium Signaling in Cholangiocytes: Methods, Mechanisms, and Effects. Int J Mol Sci 2018; 19:ijms19123913. [PMID: 30563259 PMCID: PMC6321159 DOI: 10.3390/ijms19123913] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/13/2018] [Accepted: 11/20/2018] [Indexed: 02/06/2023] Open
Abstract
Calcium (Ca2+) is a versatile second messenger that regulates a number of cellular processes in virtually every type of cell. The inositol 1,4,5-trisphosphate receptor (ITPR) is the only intracellular Ca2+ release channel in cholangiocytes, and is therefore responsible for Ca2+-mediated processes in these cells. This review will discuss the machinery responsible for Ca2+ signals in these cells, as well as experimental models used to investigate cholangiocyte Ca2+ signaling. We will also discuss the role of Ca2+ in the normal and abnormal regulation of secretion and apoptosis in cholangiocytes, two of the best characterized processes mediated by Ca2+ in this cell type.
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Affiliation(s)
- Michele Angela Rodrigues
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8019, USA.
| | - Dawidson Assis Gomes
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8019, USA.
- Department of Biochemistry and Immunology, Federal University of Minas Gerais. Av. Antônio Carlos, 6627, Belo Horizonte-MG 31270-901, Brazil.
| | - Michael Harris Nathanson
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8019, USA.
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31
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Debray D, El Mourabit H, Merabtene F, Brot L, Ulveling D, Chrétien Y, Rainteau D, Moszer I, Wendum D, Sokol H, Housset C. Diet-Induced Dysbiosis and Genetic Background Synergize With Cystic Fibrosis Transmembrane Conductance Regulator Deficiency to Promote Cholangiopathy in Mice. Hepatol Commun 2018; 2:1533-1549. [PMID: 30556040 PMCID: PMC6287479 DOI: 10.1002/hep4.1266] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/19/2018] [Indexed: 02/06/2023] Open
Abstract
The most typical expression of cystic fibrosis (CF)-related liver disease is a cholangiopathy that can progress to cirrhosis. We aimed to determine the potential impact of environmental and genetic factors on the development of CF-related cholangiopathy in mice. Cystic fibrosis transmembrane conductance regulator (Cftr)-/- mice and Cftr +/+ littermates in a congenic C57BL/6J background were fed a high medium-chain triglyceride (MCT) diet. Liver histopathology, fecal microbiota, intestinal inflammation and barrier function, bile acid homeostasis, and liver transcriptome were analyzed in 3-month-old males. Subsequently, MCT diet was changed for chow with polyethylene glycol (PEG) and the genetic background for a mixed C57BL/6J;129/Ola background (resulting from three backcrosses), to test their effect on phenotype. C57BL/6J Cftr -/- mice on an MCT diet developed cholangiopathy features that were associated with dysbiosis, primarily Escherichia coli enrichment, and low-grade intestinal inflammation. Compared with Cftr +/+ littermates, they displayed increased intestinal permeability and a lack of secondary bile acids together with a low expression of ileal bile acid transporters. Dietary-induced (chow with PEG) changes in gut microbiota composition largely prevented the development of cholangiopathy in Cftr -/- mice. Regardless of Cftr status, mice in a mixed C57BL/6J;129/Ola background developed fatty liver under an MCT diet. The Cftr -/- mice in the mixed background showed no cholangiopathy, which was not explained by a difference in gut microbiota or intestinal permeability, compared with congenic mice. Transcriptomic analysis of the liver revealed differential expression, notably of immune-related genes, in mice of the congenic versus mixed background. In conclusion, our findings suggest that CFTR deficiency causes abnormal intestinal permeability, which, combined with diet-induced dysbiosis and immune-related genetic susceptibility, promotes CF-related cholangiopathy.
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Affiliation(s)
- Dominique Debray
- Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France.,Assistance Publique-Hôpitaux de Paris, Hôpital Necker Enfants Malades Pediatric Hepatology Unit Paris France
| | - Haquima El Mourabit
- Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France
| | - Fatiha Merabtene
- Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France
| | - Loïc Brot
- Sorbonne Université, INSERM ERL U1157 Paris France
| | - Damien Ulveling
- Sorbonne Université, INSERM Institut du Cerveau et de la Moelle Epinière (ICM), Bioinformatics-Biostatistics Core Facility Paris France
| | - Yves Chrétien
- Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France
| | | | - Ivan Moszer
- Sorbonne Université, INSERM Institut du Cerveau et de la Moelle Epinière (ICM), Bioinformatics-Biostatistics Core Facility Paris France
| | - Dominique Wendum
- Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France.,Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine Pathology Department Paris France
| | - Harry Sokol
- Sorbonne Université, INSERM ERL U1157 Paris France.,Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine Department of Hepato-Gastroenterology Paris France
| | - Chantal Housset
- Sorbonne Université, INSERM Centre de Recherche Saint-Antoine (CRSA), and Institute of Cardiometabolism and Nutrition (ICAN) Paris France.,Assistance Publique-Hôpitaux de Paris, Hôpital Saint-Antoine Department of Hepato-Gastroenterology Paris France
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32
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Wu N, Meng F, Zhou T, Venter J, Giang TK, Kyritsi K, Wu C, Alvaro D, Onori P, Mancinelli R, Gaudio E, Francis H, Alpini G, Glaser S, Franchitto A. The Secretin/Secretin Receptor Axis Modulates Ductular Reaction and Liver Fibrosis through Changes in Transforming Growth Factor-β1-Mediated Biliary Senescence. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:2264-2280. [PMID: 30036520 PMCID: PMC6168967 DOI: 10.1016/j.ajpath.2018.06.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/26/2018] [Accepted: 06/19/2018] [Indexed: 12/12/2022]
Abstract
Activation of the secretin (Sct)/secretin receptor (SR) axis stimulates ductular reaction and liver fibrosis, which are hallmarks of cholangiopathies. Our aim was to define the role of Sct-regulated cellular senescence, and we demonstrated that both ductular reaction and liver fibrosis are significantly reduced in Sct-/-, SR-/-, and Sct-/-/SR-/- bile duct ligated (BDL) mice compared with BDL wild-type mice. The reduction in hepatic fibrosis in Sct-/-, SR-/-, and Sct-/-/SR-/- BDL mice was accompanied by reduced transforming growth factor-β1 levels in serum and cholangiocyte supernatant, as well as decreased expression of markers of cellular senescence in cholangiocytes in contrast to enhanced cellular senescence in hepatic stellate cells compared with BDL wild-type mice. Secretin directly stimulated the senescence of cholangiocytes and regulated, by a paracrine mechanism, the senescence of hepatic stellate cells and liver fibrosis via modulation of transforming growth factor-β1 biliary secretion. Targeting senescent cholangiocytes may represent a novel therapeutic approach for ameliorating hepatic fibrosis during cholestatic liver injury.
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Affiliation(s)
- Nan Wu
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas
| | - Fanyin Meng
- Central Texas Veterans Health Care System, Temple, Texas; Baylor Scott & White Digestive Disease Research Center, Baylor Scott & White Health Care, Temple, Texas
| | - Tianhao Zhou
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas
| | - Julie Venter
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas
| | - Thao K Giang
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas
| | - Konstantina Kyritsi
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas
| | - Chaodong Wu
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas
| | | | - Paolo Onori
- Department of Anatomical, Histological, Forensic Medicine and Orthopaedics Sciences, Sapienza, Rome, Italy
| | - Romina Mancinelli
- Department of Anatomical, Histological, Forensic Medicine and Orthopaedics Sciences, Sapienza, Rome, Italy
| | - Eugenio Gaudio
- Department of Anatomical, Histological, Forensic Medicine and Orthopaedics Sciences, Sapienza, Rome, Italy
| | - Heather Francis
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas; Central Texas Veterans Health Care System, Temple, Texas; Baylor Scott & White Digestive Disease Research Center, Baylor Scott & White Health Care, Temple, Texas
| | - Gianfranco Alpini
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas; Central Texas Veterans Health Care System, Temple, Texas; Baylor Scott & White Digestive Disease Research Center, Baylor Scott & White Health Care, Temple, Texas.
| | - Shannon Glaser
- Department of Medical Physiology, Department of Research, Texas A&M University College of Medicine, Temple, Texas; Central Texas Veterans Health Care System, Temple, Texas; Baylor Scott & White Digestive Disease Research Center, Baylor Scott & White Health Care, Temple, Texas
| | - Antonio Franchitto
- Department of Anatomical, Histological, Forensic Medicine and Orthopaedics Sciences, Sapienza, Rome, Italy; Department of Medicine, Sapienza, Rome, Italy; Eleonora Lorillard Spencer Cenci Foundation, Rome, Italy
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33
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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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34
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Fiorotto R, Amenduni M, Mariotti V, Cadamuro M, Fabris L, Spirli C, Strazzabosco M. Animal models for cystic fibrosis liver disease (CFLD). Biochim Biophys Acta Mol Basis Dis 2018; 1865:965-969. [PMID: 30071276 DOI: 10.1016/j.bbadis.2018.07.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/20/2022]
Abstract
Liver disease is a severe complication in patients with Cystic Fibrosis (CF), a genetic disease caused by mutations in the gene encoding for cystic fibrosis transmembrane conductance regulator (CFTR) channel. The sequence of events leading to CFLD is still unclear and has limited the development of more specific treatments other than the bile acid UDCA. However, in the last twenty years, several gaps have been filled, which have mainly been possible due to the availability of different animal models that mimic CF. CF mice, although they lack a spontaneous liver manifestation, have been essential to better understand the multiple functions of CFTR expression on the apical membrane of cholangiocytes, from chloride channel to regulator of epithelial innate immunity. Additionally, we have learned that the gut microbiota might be a pathogenetic factor for the development of liver disease. The recent creation of novel CF animal models (i.e. pig and ferret) that better reproduce the human disease, will allow for comparative studies with species that spontaneously develop the liver disease and will hopefully lead to novel therapeutic treatments. In this review, we have compared and summarized the main features of the current available CF animal models and their applicability for the study of the liver phenotype.
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Affiliation(s)
- Romina Fiorotto
- Digestive Disease Section, Yale Liver Center, Yale University School of Medicine, New Haven, CT, USA
| | - Mariangela Amenduni
- Digestive Disease Section, Yale Liver Center, Yale University School of Medicine, New Haven, CT, USA
| | - Valeria Mariotti
- Department of Molecular Medicine, University of Padova School of Medicine, Padova, Italy
| | - Massimiliano Cadamuro
- Department of Molecular Medicine, University of Padova School of Medicine, Padova, Italy
| | - Luca Fabris
- Department of Molecular Medicine, University of Padova School of Medicine, Padova, Italy
| | - Carlo Spirli
- Digestive Disease Section, Yale Liver Center, Yale University School of Medicine, New Haven, CT, USA.
| | - Mario Strazzabosco
- Digestive Disease Section, Yale Liver Center, Yale University School of Medicine, New Haven, CT, USA
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35
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Oliva-Vilarnau N, Hankeova S, Vorrink SU, Mkrtchian S, Andersson ER, Lauschke VM. Calcium Signaling in Liver Injury and Regeneration. Front Med (Lausanne) 2018; 5:192. [PMID: 30023358 PMCID: PMC6039545 DOI: 10.3389/fmed.2018.00192] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/11/2018] [Indexed: 12/12/2022] Open
Abstract
The liver fulfills central roles in metabolic control and detoxification and, as such, is continuously exposed to a plethora of insults. Importantly, the liver has a unique ability to regenerate and can completely recoup from most acute, non-iterative insults. However, multiple conditions, including viral hepatitis, non-alcoholic fatty liver disease (NAFLD), long-term alcohol abuse and chronic use of certain medications, can cause persistent injury in which the regenerative capacity eventually becomes dysfunctional, resulting in hepatic scaring and cirrhosis. Calcium is a versatile secondary messenger that regulates multiple hepatic functions, including lipid and carbohydrate metabolism, as well as bile secretion and choleresis. Accordingly, dysregulation of calcium signaling is a hallmark of both acute and chronic liver diseases. In addition, recent research implicates calcium transients as essential components of liver regeneration. In this review, we provide a comprehensive overview of the role of calcium signaling in liver health and disease and discuss the importance of calcium in the orchestration of the ensuing regenerative response. Furthermore, we highlight similarities and differences in spatiotemporal calcium regulation between liver insults of different etiologies. Finally, we discuss intracellular calcium control as an emerging therapeutic target for liver injury and summarize recent clinical findings of calcium modulation for the treatment of ischemic-reperfusion injury, cholestasis and NAFLD.
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Affiliation(s)
- Nuria Oliva-Vilarnau
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Simona Hankeova
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Sabine U Vorrink
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Souren Mkrtchian
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Emma R Andersson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Volker M Lauschke
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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36
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Li Q, Dutta A, Kresge C, Bugde A, Feranchak AP. Bile acids stimulate cholangiocyte fluid secretion by activation of transmembrane member 16A Cl - channels. Hepatology 2018; 68:187-199. [PMID: 29360145 PMCID: PMC6055743 DOI: 10.1002/hep.29804] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 01/12/2018] [Accepted: 01/18/2018] [Indexed: 12/28/2022]
Abstract
UNLABELLED Bile acids stimulate a bicarbonate-rich choleresis, in part, through effects on cholangiocytes. Because Cl- channels in the apical membrane of cholangiocytes provide the driving force for secretion and transmembrane member 16A (TMEM16A) has been identified as the Ca2+ -activated Cl- channel in the apical membrane of cholangiocytes, the aim of the present study was to determine whether TMEM16A is the target of bile-acid-stimulated Cl- secretion and to identify the regulatory pathway involved. In these studies of mouse, rat, and human biliary epithelium exposure to ursodeoxycholic acid (UDCA) or tauroursodeoxycholic acid (TUDCA) rapidly increased the rate of exocytosis, ATP release, [Ca2+ ]i , membrane Cl- permeability, and transepithelial secretion. Bile-acid-stimulated Cl- currents demonstrated biophysical properties consistent with TMEM16A and were inhibited by pharmacological or molecular (small-interfering RNA; siRNA) inhibition of TMEM16A. Bile acid-stimulated Cl- currents were not observed in the presence of apyrase, suramin, or 2-aminoethoxydiphenyl borate (2-APB), demonstrating that current activation requires extracellular ATP, P2Y, and inositol 1,4,5-trisphosphate (IP3) receptors. TUDCA did not activate Cl- currents during pharmacologic inhibition of the apical Na+ -dependent bile acid transporter (ASBT), but direct intracellular delivery of TUDCA rapidly activated Cl- currents. CONCLUSION Bile acids stimulate Cl- secretion in mouse and human biliary cells through activation of membrane TMEM16A channels in a process regulated by extracellular ATP and [Ca2+ ]i . These studies suggest that TMEM16A channels may be targets to increase bile flow during cholestasis. (Hepatology 2018;68:187-199).
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Affiliation(s)
- Qin Li
- Department of PhysiologyJianghan University School of MedicineWuhanChina,Department of PediatricsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Amal Dutta
- Department of PediatricsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Charles Kresge
- Department of PediatricsUniversity of Texas Southwestern Medical CenterDallasTX
| | - Abhijit Bugde
- Departments of Cell BiologyUniversity of Texas Southwestern Medical CenterDallasTX
| | - Andrew P. Feranchak
- Department of PediatricsUniversity of Texas Southwestern Medical CenterDallasTX
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37
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Rottgen TS, Nickerson AJ, Rajendran VM. Calcium-Activated Cl - Channel: Insights on the Molecular Identity in Epithelial Tissues. Int J Mol Sci 2018; 19:E1432. [PMID: 29748496 PMCID: PMC5983713 DOI: 10.3390/ijms19051432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/25/2022] Open
Abstract
Calcium-activated chloride secretion in epithelial tissues has been described for many years. However, the molecular identity of the channel responsible for the Ca2+-activated Cl− secretion in epithelial tissues has remained a mystery. More recently, TMEM16A has been identified as a new putative Ca2+-activated Cl− channel (CaCC). The primary goal of this article will be to review the characterization of TMEM16A, as it relates to the physical structure of the channel, as well as important residues that confer voltage and Ca2+-sensitivity of the channel. This review will also discuss the role of TMEM16A in epithelial physiology and potential associated-pathophysiology. This will include discussion of developed knockout models that have provided much needed insight on the functional localization of TMEM16A in several epithelial tissues. Finally, this review will examine the implications of the identification of TMEM16A as it pertains to potential novel therapies in several pathologies.
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Affiliation(s)
- Trey S Rottgen
- Department of Physiology, Pharmacology, and Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
- Department of Biochemistry and Molecular Pharmacology, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
| | - Andrew J Nickerson
- Department of Physiology, Pharmacology, and Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
- Department of Biochemistry and Molecular Pharmacology, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
| | - Vazhaikkurichi M Rajendran
- Department of Physiology, Pharmacology, and Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
- Department of Biochemistry and Molecular Pharmacology, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
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38
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Hatano N, Ohya S, Imaizumi Y, Clark RB, Belke D, Giles WR. ATP increases [Ca 2+ ] i and activates a Ca 2+ -dependent Cl - current in rat ventricular fibroblasts. Exp Physiol 2018; 103:666-682. [PMID: 29493027 DOI: 10.1113/ep086822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/22/2018] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Although electrophysiological and biophysical characteristics of heart fibroblasts have been studied in detail, their responses to prominent paracrine agents in the myocardium have not been addressed adequately. Our experiments characterize changes in cellular electrophysiology and intracellular calcium in response to ATP. What is the main finding and its importance? In rat ventricular fibroblasts maintained in cell culture, we find that ATP activates a specific subset of Ca2+ -activated Cl- channels as a consequence of binding to P2Y purinoceptors and then activating phospholipase C. This response is not dependent on [Ca2+ ]o but requires an increase in [Ca2+ ]i and is modulated by the type of nucleotide that is the purinergic agonist. ABSTRACT Effects of ATP on enzymatically isolated rat ventricular fibroblasts maintained in short-term (36-72 h) cell culture were examined. Immunocytochemical staining of these cells revealed that a fibroblast, as opposed to a myofibroblast, phenotype was predominant. ATP, ADP or uridine 5'-triphosphate (UTP) all produced large increases in [Ca2+ ]i . Voltage-clamp studies (amphotericin-perforated patch) showed that ATP (1-100 μm) activated an outwardly rectifying current, with a reversal potential very close to the Nernst potential for Cl- . In contrast, ADP was much less effective, and UTP produced no detectable current. The non-selective Cl- channel blockers niflumic acid, DIDS and NPPB (each at 100 μm), blocked the responses to 100 μm ATP. An agonist for P2Y purinoceptors, 2-MTATP, activated a very similar outwardly rectifying C1- current. The P2Y receptor antagonists, suramin and PPADS (100 μm each), significantly inhibited the Cl- current produced by 100 μm ATP. ATP was able to activate this Cl- current when [Ca2+ ]o was removed, but not when [Ca2+ ]i was buffered with BAPTA-AM. In the presence of the phospholipase C inhibitor U73122, this Cl- current could not be activated. PCR analysis revealed strong signals for a number of P2Y purinoceptors and for the Ca2+ -activated Cl- channel, TMEM16F (also denoted ANO6). In summary, these results demonstrate that activation of P2Y receptors by ATP causes a phospholipase C-dependent increase in [Ca2+ ]i , followed by activation of a Ca2+ -dependent Cl- current in rat ventricular fibroblasts.
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Affiliation(s)
- Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya, Japan
| | - Susumu Ohya
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, 467-8601, Japan
| | - Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Robert B Clark
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Darrell Belke
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Wayne R Giles
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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39
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Feranchak AP. Cystic fibrosis transmembrane conductance regulator: Actin(g) as a master regulator of cholangiocyte function. Hepatology 2018; 67:833-836. [PMID: 29023826 DOI: 10.1002/hep.29583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/21/2017] [Accepted: 10/03/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Andrew P Feranchak
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX
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40
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Karlsen TH, Folseraas T, Thorburn D, Vesterhus M. Primary sclerosing cholangitis - a comprehensive review. J Hepatol 2017; 67:1298-1323. [PMID: 28802875 DOI: 10.1016/j.jhep.2017.07.022] [Citation(s) in RCA: 462] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 07/15/2017] [Accepted: 07/22/2017] [Indexed: 02/07/2023]
Abstract
Primary sclerosing cholangitis (PSC) is a rare disorder characterised by multi-focal bile duct strictures and progressive liver disease. Inflammatory bowel disease is usually present and there is a high risk of cholangiocarcinoma and colorectal cancer. Most patients ultimately require liver transplantation, after which disease recurrence may occur. With limited therapeutic options and a lack of proven surveillance strategies, patients currently have significant unmet needs. In the present seminar, we provide a comprehensive review of the status of the field. We emphasise developments related to patient stratification and disease behaviour, and provide an overview of management options from a practical, patient-centered perspective. We survey advances made in the understanding of PSC pathogenesis and summarise the ongoing efforts to develop an effective therapy based on these insights.
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Affiliation(s)
- Tom H Karlsen
- Norwegian PSC Research Center, Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Norway; Research Institute of Internal Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital Rikshospitalet, Oslo, Norway.
| | - Trine Folseraas
- Norwegian PSC Research Center, Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital Rikshospitalet, Oslo, Norway; Research Institute of Internal Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Douglas Thorburn
- UCL Institute for Liver and Digestive Health, Division of Medicine, University College London, UK; Sheila Sherlock Liver Centre, Royal Free London NHS Foundation Trust, London, UK
| | - Mette Vesterhus
- Norwegian PSC Research Center, Department of Transplantation Medicine, Division of Surgery, Inflammatory Medicine and Transplantation, Oslo University Hospital Rikshospitalet, Oslo, Norway; National Centre for Ultrasound in Gastroenterology, Haukeland University Hospital, Bergen, Norway
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41
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Zaidman NA, Panoskaltsis-Mortari A, O'Grady SM. Large-conductance Ca 2+ -activated K + channel activation by apical P2Y receptor agonists requires hydrocortisone in differentiated airway epithelium. J Physiol 2017; 595:4631-4645. [PMID: 28481415 DOI: 10.1113/jp274200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/02/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Hydrocortisone (HC) is required for activation of large-conductance Ca2+ -activated K+ current (BK) by purinergic receptor agonists. HC reduces insertion of the stress-regulated exon (STREX) in the KCNMA1 gene, permitting protein kinase C (PKC)-dependent channel activation. Overlapping and unique purinergic signalling regions exist at the apical border of differentiated surface cells. BK channels localize in the cilia of surface cells. ABSTRACT In the present study we investigated the role of hydrocortisone (HC) on uridine-5'-triphosphate (UTP)-stimulated ion transport in differentiated, pseudostratified epithelia derived from normal human bronchial basal cells. The presence of a UTP-stimulated, paxilline-sensitive large-conductance Ca2+ -activated K+ (BK) current was demonstrated in control epithelia but was not stimulated in epithelia differentiated in the absence of HC (HC0). Addition of the BK channel opener NS11021 directly activated channels in control epithelia; however, under HC0 conditions, activation only occurred when UTP was added after NS11021. The PKC inhibitors GF109203x and Gö6983 blocked BK activation by UTP in control epithelia, suggesting that PKC-mediated phosphorylation plays a permissive role in purinoceptor-stimulated BK activation. Moreover, HC0 epithelia expressed significantly more KCNMA1 containing the stress-regulated exon (STREX), a splice-variant of the α-subunit that displays altered channel regulation by phosphorylation, compared to control epithelia. Furthermore, BK channels as well as purinergic receptors were shown to localize in unique and overlapping domains at the apical membrane of ciliated surface cells. These results establish a previously unrecognized role for glucocorticoids in regulation of BK channels in airway epithelial cells.
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Affiliation(s)
- Nathan A Zaidman
- Department of Integrative Biology and Physiology, University of Minnesota, 6-125 Jackson Hall, Minneapolis, MN, USA
| | - Angela Panoskaltsis-Mortari
- Department of Integrative Biology and Physiology, University of Minnesota, 6-125 Jackson Hall, Minneapolis, MN, USA.,Department of Pediatrics, University of Minnesota, 660E MCRB, Minneapolis, MN, USA
| | - Scott M O'Grady
- Department of Integrative Biology and Physiology, University of Minnesota, 6-125 Jackson Hall, Minneapolis, MN, USA.,Department of Animal Science, University of Minnesota, 480 Haecker Hall, St. Paul, Minneapolis, MN, USA
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Hahn A, Faulhaber J, Srisawang L, Stortz A, Salomon JJ, Mall MA, Frings S, Möhrlen F. Cellular distribution and function of ion channels involved in transport processes in rat tracheal epithelium. Physiol Rep 2017; 5:e13290. [PMID: 28642338 PMCID: PMC5492199 DOI: 10.14814/phy2.13290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 01/17/2023] Open
Abstract
Transport of water and electrolytes in airway epithelia involves chloride-selective ion channels, which are controlled either by cytosolic Ca2+ or by cAMP The contributions of the two pathways to chloride transport differ among vertebrate species. Because rats are becoming more important as animal model for cystic fibrosis, we have examined how Ca2+- dependent and cAMP- dependent Cl- secretion is organized in the rat tracheal epithelium. We examined the expression of the Ca2+-gated Cl- channel anoctamin 1 (ANO1), the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel, the epithelial Na+ channel ENaC, and the water channel aquaporin 5 (AQP5) in rat tracheal epithelium. The contribution of ANO1 channels to nucleotide-stimulated Cl- secretion was determined using the channel blocker Ani9 in short-circuit current recordings obtained from primary cultures of rat tracheal epithelial cells in Ussing chambers. We found that ANO1, CFTR and AQP5 proteins were expressed in nonciliated cells of the tracheal epithelium, whereas ENaC was expressed in ciliated cells. Among nonciliated cells, ANO1 occurred together with CFTR and Muc5b and, in addition, in a different cell type without CFTR and Muc5b. Bioelectrical studies with the ANO1-blocker Ani9 indicated that ANO1 mediated the secretory response to the nucleotide uridine-5'-triphosphate. Our data demonstrate that, in rat tracheal epithelium, Cl- secretion and Na+ absorption are routed through different cell types, and that ANO1 channels form the molecular basis of Ca2+-dependent Cl- secretion in this tissue. These characteristic features of Cl--dependent secretion reveal similarities and distinct differences to secretory processes in human airways.
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Affiliation(s)
- Anne Hahn
- Department of Animal Molecular Physiology, Centre of Organismal Studies University of Heidelberg, Heidelberg, Germany
| | - Johannes Faulhaber
- Department of Animal Molecular Physiology, Centre of Organismal Studies University of Heidelberg, Heidelberg, Germany
| | - Lalita Srisawang
- Department of Animal Molecular Physiology, Centre of Organismal Studies University of Heidelberg, Heidelberg, Germany
| | - Andreas Stortz
- Department of Animal Molecular Physiology, Centre of Organismal Studies University of Heidelberg, Heidelberg, Germany
| | - Johanna J Salomon
- Department of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC) German Center for Lung Research (DZL) University of Heidelberg, Heidelberg, Germany
| | - Marcus A Mall
- Department of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC) German Center for Lung Research (DZL) University of Heidelberg, Heidelberg, Germany
| | - Stephan Frings
- Department of Animal Molecular Physiology, Centre of Organismal Studies University of Heidelberg, Heidelberg, Germany
| | - Frank Möhrlen
- Department of Animal Molecular Physiology, Centre of Organismal Studies University of Heidelberg, Heidelberg, Germany
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Wu MM, Lou J, Song BL, Gong YF, Li YC, Yu CJ, Wang QS, Ma TX, Ma K, Hartzell HC, Duan DD, Zhao D, Zhang ZR. Hypoxia augments the calcium-activated chloride current carried by anoctamin-1 in cardiac vascular endothelial cells of neonatal mice. Br J Pharmacol 2016; 171:3680-92. [PMID: 24758567 PMCID: PMC4128065 DOI: 10.1111/bph.12730] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/01/2014] [Accepted: 04/06/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE The molecular identity of calcium-activated chloride channels (CaCCs) in vascular endothelial cells remains unknown. This study sought to identify whether anoctamin-1 (Ano1, also known as TMEM16A) functions as a CaCC and whether hypoxia alters the biophysical properties of Ano1 in mouse cardiac vascular endothelial cells (CVECs). EXPERIMENTAL APPROACH Western blot, quantitative real-time PCR, confocal imaging analysis and patch-clamp analysis combined with pharmacological approaches were used to determine whether Ano1 was expressed and functioned as CaCC in CVECs. KEY RESULTS Ano1 was expressed in CVECs. The biophysical properties of the current generated in the CVECs, including the Ca2+ and voltage dependence, outward rectification, anion selectivity and the pharmacological profile, are similar to those described for CaCCs. The density of ICl(Ca) detected in CVECs was significantly inhibited by T16Ainh-A01, an Ano1 inhibitor, and a pore-targeting, specific anti-Ano1 antibody, and was markedly decreased in Ano1 gene knockdown CVECs. The density of ICl(Ca) was significantly potentiated in CVECs exposed to hypoxia, and this hypoxia-induced increase in the density of ICl(Ca) was inhibited by T16Ainh-A01 or anti-Ano1 antibody. Hypoxia also increased the current density of ICl(Ca) in Ano1 gene knockdown CVECs. CONCLUSIONS AND IMPLICATIONS Ano1 formed CaCC in CVECs of neonatal mice. Hypoxia enhances Ano1-mediated ICl(Ca) density via increasing its expression, altering the ratio of its splicing variants, sensitivity to membrane voltage and to Ca2+. Ano1 may play a role in the pathophysiological processes during ischaemia in heart, and therefore, Ano1 might be a potential therapeutic target to prevent ischaemic damage.
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Affiliation(s)
- Ming-Ming Wu
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, The 2nd Affiliated Hospital, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin Medical University, Harbin, China
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Li Q, Kresge C, Bugde A, Lamphere M, Park JY, Feranchak AP. Regulation of mechanosensitive biliary epithelial transport by the epithelial Na(+) channel. Hepatology 2016; 63:538-49. [PMID: 26475057 PMCID: PMC4780683 DOI: 10.1002/hep.28301] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 10/14/2015] [Indexed: 12/07/2022]
Abstract
UNLABELLED Intrahepatic biliary epithelial cells (BECs), also known as cholangiocytes, modulate the volume and composition of bile through the regulation of secretion and absorption. While mechanosensitive Cl(-) efflux has been identified as an important secretory pathway, the counterabsorptive pathways have not been identified. In other epithelial cells, the epithelial Na(+) channel (ENaC) has been identified as an important contributor to fluid absorption; however, its expression and function in BECs have not been previously studied. Our studies revealed the presence of α, β, and γ ENaC subunits in human BECs and α and γ subunits in mouse BECs. In studies of confluent mouse BEC monolayers, the ENaC contributes to the volume of surface fluid at the apical membrane during constitutive conditions. Further, functional studies using whole-cell patch clamp of single BECs demonstrated small constitutive Na(+) currents, which increased significantly in response to fluid-flow or shear. The magnitude of Na(+) currents was proportional to the shear force, displayed inward rectification and a reversal potential of +40 mV (ENa+ = +60 mV), and were abolished with removal of extracellular Na(+) (N-methyl-d-glucamine) or in the presence of amiloride. Transfection with ENaCα small interfering RNA significantly inhibited flow-stimulated Na(+) currents, while overexpression of the α subunit significantly increased currents. ENaC-mediated currents were positively regulated by proteases and negatively regulated by extracellular adenosine triphosphate. CONCLUSION These studies represent the initial characterization of mechanosensitive Na(+) currents activated by flow in biliary epithelium; understanding the role of mechanosensitive transport pathways may provide strategies to modulate the volume and composition of bile during cholestatic conditions. (Hepatology 2016;63:538-549).
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Affiliation(s)
- Qin Li
- Department of Physiology, Jianhan University School of Medicine, Wuhan, China,Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Charles Kresge
- Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Abhijit Bugde
- Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Michelle Lamphere
- Department of Pathology and Laboratory Medicine, Children’s Health, Children’s Medical Center, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jason Y. Park
- Department of Pathology and Laboratory Medicine, Children’s Health, Children’s Medical Center, University of Texas Southwestern Medical Center, Dallas, TX,Pathology, University of Texas Southwestern Medical Center, Dallas, TX,Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX
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Dutta AK, Khimji AK, Liu S, Karamysheva Z, Fujita A, Kresge C, Rockey DC, Feranchak AP. PKCα regulates TMEM16A-mediated Cl⁻ secretion in human biliary cells. Am J Physiol Gastrointest Liver Physiol 2016; 310:G34-42. [PMID: 26542395 PMCID: PMC4698437 DOI: 10.1152/ajpgi.00146.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/31/2015] [Indexed: 02/07/2023]
Abstract
TMEM16A is a newly identified Ca(2+)-activated Cl(-) channel in biliary epithelial cells (BECs) that is important in biliary secretion. While extracellular ATP stimulates TMEM16A via binding P2 receptors and increasing intracellular Ca(2+) concentration ([Ca(2+)]i), the regulatory pathways have not been elucidated. Protein kinase C (PKC) contributes to ATP-mediated secretion in BECs, although its potential role in TMEM16A regulation is unknown. To determine whether PKCα regulates the TMEM16A-dependent membrane Cl(-) transport in BECs, studies were performed in human biliary Mz-cha-1 cells. Addition of extracellular ATP induced a rapid translocation of PKCα from the cytosol to the plasma membrane and activation of whole cell Ca(2+)-activated Cl(-) currents. Currents demonstrated outward rectification and reversal at 0 mV (properties consistent with TMEM16A) and were inhibited by either molecular (siRNA) or pharmacologic (PMA or Gö6976) inhibition of PKCα. Intracellular dialysis with recombinant PKCα activated Cl(-) currents with biophysical properties identical to TMEM16A in control cells but not in cells after transfection with TMEM16A siRNA. In conclusion, our studies demonstrate that PKCα is coupled to ATP-stimulated TMEM16A activation in BECs. Targeting this ATP-Ca(2+)-PKCα signaling pathway may represent a therapeutic strategy to increase biliary secretion and promote bile formation.
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Affiliation(s)
- Amal K. Dutta
- 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas;
| | | | - Songling Liu
- 4Department of Internal Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Zemfira Karamysheva
- 3Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Akiko Fujita
- 2Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas;
| | - Charles Kresge
- 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas;
| | - Don C. Rockey
- 4Department of Internal Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Andrew P. Feranchak
- 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas;
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Modulating Ca²⁺ signals: a common theme for TMEM16, Ist2, and TMC. Pflugers Arch 2015; 468:475-90. [PMID: 26700940 DOI: 10.1007/s00424-015-1767-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 12/21/2022]
Abstract
Since the discovery of TMEM16A (anoctamin 1, ANO1) as Ca(2+)-activated Cl(-) channel, the protein was found to serve different physiological functions, depending on the type of tissue. Subsequent reports on other members of the anoctamin family demonstrated a broad range of yet poorly understood properties. Compromised anoctamin function is causing a wide range of diseases, such as hearing loss (ANO2), bleeding disorder (ANO6), ataxia and dystonia (ANO3, 10), persistent borrelia and mycobacteria infection (ANO10), skeletal syndromes like gnathodiaphyseal dysplasia and limb girdle muscle dystrophy (ANO5), and cancer (ANO1, 6, 7). Animal models demonstrate CF-like airway disease, asthma, and intestinal hyposecretion (ANO1). Although present data indicate that ANO1 is a Ca(2+)-activated Cl(-) channel, it remains unclear whether all anoctamins form plasma membrane-localized or intracellular chloride channels. We find Ca(2+)-activated Cl(-) currents appearing by expression of most anoctamin paralogs, including the Nectria haematococca homologue nhTMEM16 and the yeast homologue Ist2. As recent studies show a role of anoctamins, Ist2, and the related transmembrane channel-like (TMC) proteins for intracellular Ca(2+) signaling, we will discuss the role of these proteins in generating compartmentalized Ca(2+) signals, which may give a hint as to the broad range of cellular functions of anoctamins.
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Ye Z, Wu MM, Wang CY, Li YC, Yu CJ, Gong YF, Zhang J, Wang QS, Song BL, Yu K, Hartzell HC, Duan DD, Zhao D, Zhang ZR. Characterization of Cardiac Anoctamin1 Ca²⁺-Activated Chloride Channels and Functional Role in Ischemia-Induced Arrhythmias. J Cell Physiol 2015; 230:337-46. [PMID: 24962810 DOI: 10.1002/jcp.24709] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/20/2014] [Indexed: 12/17/2022]
Abstract
Anoctamin1 (ANO1) encodes a Ca(2+)-activated chloride (Cl(-)) channel (CaCC) in variety tissues of many species. Whether ANO1 expresses and functions as a CaCC in cardiomyocytes remain unknown. The objective of this study is to characterize the molecular and functional expression of ANO1 in cardiac myocytes and the role of ANO1-encoded CaCCs in ischemia-induced arrhythmias in the heart. Quantitative real-time RT-PCR, immunofluorescence staining assays, and immunohistochemistry identified the molecular expression, location, and distribution of ANO1 in mouse ventricular myocytes (mVMs). Patch-clamp recordings combined with pharmacological analyses found that ANO1 was responsible for a Ca(2+)-activated Cl(-) current (I(Cl.Ca)) in cardiomyocytes. Myocardial ischemia led to a significant increase in the current density of I(Cl.Ca), which was inhibited by a specific ANO1 inhibitor, T16A(inh)-A01, and an antibody targeting at the pore area of ANO1. Moreover, cardiomyocytes isolated from mice with ischemia-induced arrhythmias had an accelerated early phase 1 repolarization of action potentials (APs) and a deeper "spike and dome" compared to control cardiomyocytes from non-ischemia mice. Application of the antibody targeting at ANO1 pore prevented the ischemia-induced early phase 1 repolarization acceleration and caused a much shallower "spike and dome". We conclude that ANO1 encodes CaCC and plays a significant role in the phase 1 repolarization of APs in mVMs. The ischemia-induced increase in ANO1 expression may be responsible for the increased density of I(Cl.Ca) in the ischemic heart and may contribute, at least in part, to ischemia-induced arrhythmias.
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Affiliation(s)
- Zhen Ye
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Ming-Ming Wu
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Chun-Yu Wang
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Yan-Chao Li
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Chang-Jiang Yu
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Yuan-Feng Gong
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Jun Zhang
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Qiu-Shi Wang
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Bin-Lin Song
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Kuai Yu
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia
| | - Dayue Darrel Duan
- Laboratory of Cardiovascular Phenomics, Department of Pharmacology, Center for Molecular Medicine, School of Medicine University of Nevada, Reno, Nevada
| | - Dan Zhao
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
| | - Zhi-Ren Zhang
- Departments of Clinical Pharmacy and Cardiology, The 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, P. R. China
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Guerra MT, Nathanson MH. Calcium signaling and secretion in cholangiocytes. Pancreatology 2015; 15:S44-8. [PMID: 26100660 PMCID: PMC4603373 DOI: 10.1016/j.pan.2015.05.477] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 05/08/2015] [Accepted: 05/27/2015] [Indexed: 12/11/2022]
Abstract
Alcoholic hepatitis affects up to one-third of individuals who abuse alcohol and can be associated with high mortality. Although this disorder is characterized by hepatocellular damage, steatosis and neutrophil infiltration, recent evidence suggests that cholestasis or impaired bile secretion may be a frequent occurrence as well. Bile secretion results from the concerted activity of hepatocytes and cholangiocytes, the epithelial cells that line the bile ducts. Hepatocytes secrete bile acids and conjugated products into the bile canaliculi, which then are modified by cholangiocytes through secretion of bicarbonate and water to give rise to the final secreted bile. Here the molecular mechanisms regulating bile secretion in cholangiocytes are reviewed. Moreover, we discuss how the expression of intracellular Ca(2+) channels might be regulated in cholangiocytes, plus evidence that components of the Ca(2+) signaling machinery are altered in a range of cholestatic diseases of the bile ducts.
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Affiliation(s)
- Mateus T. Guerra
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine
| | - Michael H. Nathanson
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine,Correspondence to: Michael H. Nathanson, 300 Cedar Street, TAC S241D, New Haven, CT. USA. 06520-8019, Phone: +1 203 785 7312, Fax: +1 203 785 7273,
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Bradley E, Fedigan S, Webb T, Hollywood MA, Thornbury KD, McHale NG, Sergeant GP. Pharmacological characterization of TMEM16A currents. Channels (Austin) 2015; 8:308-20. [PMID: 24642630 DOI: 10.4161/chan.28065] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent studies have shown that transmembrane protein 16 A (TMEM16A) is a subunit of calcium-activated chloride channels (CACCs). Pharmacological agents have been used to probe the functional role of CACCs, however their effect on TMEM16A currents has not been systematically investigated. In the present study, we characterized the voltage and concentration-dependent effects of 2 traditional CACC inhibitors (niflumic acid and anthracene-9-carboxcylic acid) and 2 novel CACC / TMEM16A inhibitors (CACC(inh)A01 and T16A(inh)A01) on TMEM16A currents. The whole cell patch clamp technique was used to record TMEM16A currents from HE K 293 cells that stably expressed human TMEM16A. Niflumic acid, A-9-C, CACC(inh)A01 and T16A(inh)A01 inhibited TMEM16A currents with IC50 values of 12, 58, 1.7 and 1.5 μM, respectively, however, A-9-C and niflumic acid were less efficacious at negative membrane potentials. A-9-C and niflumic acid reduced the rate of TMEM16A tail current deactivation at negative membrane potentials and A-9-C (1 mM) enhanced peak TMEM16A tail current amplitude. In contrast, the inhibitory effects of CACC(inh)A01 and T16A(inh)A01 were independent of voltage and they did not prolong the rate of TMEM16A tail current deactivation. The effects of niflumic acid and A-9-C on TMEM16A currents were similar to previous observations on CACCs in vascular smooth muscle, strengthening the hypothesis that they are encoded by TMEM16A. However, CACC(inh)A01 and T16A(inh)A01 were more potent inhibitors of TMEM16A channels and their effects were not diminished at negative membrane potentials making them attractive candidates to interrogate the functional role of TMEM16A channels in future studies.
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Abstract
Cholangiocytes are the epithelial cells that line the bile ducts. Along the biliary tree, two different kinds of cholangiocytes exist; small and large cholangiocytes. Each type has important differences in their biological role in physiological and pathological conditions. In response to injury, cholangiocytes become reactive and acquire a neuroendocrine-like phenotype with the secretion of a number of peptides. These molecules act in an autocrine/paracrine fashion to modulate cholangiocyte biology and determine the evolution of biliary damage. The failure of such mechanisms is believed to influence the progression of cholangiopathies, a group of diseases that selectively target biliary cells. Therefore, the understanding of mechanisms regulating cholangiocyte response to injury is expected to foster the development of new therapeutic options to treat biliary diseases. In the present review, we will discuss the most recent findings in the mechanisms driving cholangiocyte adaptation to damage, with particular emphasis on molecular pathways that are susceptible of therapeutic intervention. Morphogenic pathways (Hippo, Notch, Hedgehog), which have been recently shown to regulate biliary ontogenesis and response to injury, will also be reviewed. In addition, the results of ongoing clinical trials evaluating new drugs for the treatment of cholangiopathies will be discussed.
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