1
|
Mata-Martínez E, Ramírez-Ledesma MG, Vázquez-Victorio G, Hernández-Muñoz R, Díaz-Muñoz M, Vázquez-Cuevas FG. Purinergic Signaling in Non-Parenchymal Liver Cells. Int J Mol Sci 2024; 25:9447. [PMID: 39273394 PMCID: PMC11394727 DOI: 10.3390/ijms25179447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Revised: 08/27/2024] [Accepted: 08/29/2024] [Indexed: 09/15/2024] Open
Abstract
Purinergic signaling has emerged as an important paracrine-autocrine intercellular system that regulates physiological and pathological processes in practically all organs of the body. Although this system has been thoroughly defined since the nineties, recent research has made substantial advances regarding its role in aspects of liver physiology. However, most studies have mainly targeted the entire organ, 70% of which is made up of parenchymal cells or hepatocytes. Because of its physiological role, the liver is exposed to toxic metabolites, such as xenobiotics, drugs, and fatty acids, as well as to pathogens such as viruses and bacteria. Under injury conditions, all cell types within the liver undergo adaptive changes. In this context, the concentration of extracellular ATP has the potential to increase dramatically. Indeed, this purinergic response has not been studied in sufficient detail in non-parenchymal liver cells. In the present review, we systematize the physiopathological adaptations related to the purinergic system in chronic liver diseases of non-parenchymal liver cells, such as hepatic stellate cells, Kupffer cells, sinusoidal endothelial cells, and cholangiocytes. The role played by non-parenchymal liver cells in these circumstances will undoubtedly be strategic in understanding the regenerative activities that support the viability of this organ under stressful conditions.
Collapse
Affiliation(s)
- Esperanza Mata-Martínez
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Mexico City 04510, Mexico
| | - María Guadalupe Ramírez-Ledesma
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Boulevard Juriquilla #3001, Querétaro 76230, Mexico
| | - Genaro Vázquez-Victorio
- Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior S/N, Ciudad Universitaria, Mexico City 04510, Mexico
| | - Rolando Hernández-Muñoz
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria, Mexico City 04510, Mexico
| | - Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Boulevard Juriquilla #3001, Querétaro 76230, Mexico
| | - Francisco G Vázquez-Cuevas
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Boulevard Juriquilla #3001, Querétaro 76230, Mexico
| |
Collapse
|
2
|
Guo Y, Mao T, Fang Y, Wang H, Yu J, Zhu Y, Shen S, Zhou M, Li H, Hu Q. Comprehensive insights into potential roles of purinergic P2 receptors on diseases: Signaling pathways involved and potential therapeutics. J Adv Res 2024:S2090-1232(24)00123-1. [PMID: 38565403 DOI: 10.1016/j.jare.2024.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/03/2024] [Accepted: 03/29/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Purinergic P2 receptors, which can be divided into ionotropic P2X receptors and metabotropic P2Y receptors, mediate cellular signal transduction of purine or pyrimidine nucleoside triphosphates and diphosphate. Based on the wide expression of purinergic P2 receptors in tissues and organs, their significance in homeostatic maintenance, metabolism, nociceptive transmission, and other physiological processes is becoming increasingly evident, suggesting that targeting purinergic P2 receptors to regulate biological functions and signal transmission holds significant promise for disease treatment. AIM OF REVIEW This review highlights the detailed mechanisms by which purinergic P2 receptors engage in physiological and pathological progress, as well as providing prospective strategies for discovering clinical drug candidates. KEY SCIENTIFIC CONCEPTS OF REVIEW The purinergic P2 receptors regulate complex signaling and molecular mechanisms in nervous system, digestive system, immune system and as a result, controlling physical health states and disease progression. There has been a significant rise in research and development focused on purinergic P2 receptors, contributing to an increased number of drug candidates in clinical trials. A few influential pioneers have laid the foundation for advancements in the evaluation, development, and of novel purinergic P2 receptors modulators, including agonists, antagonists, pharmaceutical compositions and combination strategies, despite the different scaffolds of these drug candidates. These advancements hold great potential for improving therapeutic outcomes by specifically targeting purinergic P2 receptors.
Collapse
Affiliation(s)
- Yanshuo Guo
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Tianqi Mao
- College of Pharmaceutical Sciences, Soochow University, Suzhou 215006, China
| | - Yafei Fang
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Hui Wang
- College of Pharmaceutical Sciences, Soochow University, Suzhou 215006, China
| | - Jiayue Yu
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yifan Zhu
- College of Pharmaceutical Sciences, Soochow University, Suzhou 215006, China
| | - Shige Shen
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Mengze Zhou
- School of Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Huanqiu Li
- College of Pharmaceutical Sciences, Soochow University, Suzhou 215006, China.
| | - Qinghua Hu
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China.
| |
Collapse
|
3
|
Arunachalam AR, Samuel SS, Mani A, Maynard JP, Stayer KM, Dybbro E, Narayanan S, Biswas A, Pathan S, Soni K, Kamal AHM, Ambati CSR, Putluri N, Desai MS, Thevananther S. P2Y2 purinergic receptor gene deletion protects mice from bacterial endotoxin and sepsis-associated liver injury and mortality. Am J Physiol Gastrointest Liver Physiol 2023; 325:G471-G491. [PMID: 37697947 PMCID: PMC10812707 DOI: 10.1152/ajpgi.00090.2023] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/28/2023] [Accepted: 09/11/2023] [Indexed: 09/13/2023]
Abstract
The liver plays a significant role in regulating a wide range of metabolic, homeostatic, and host-defense functions. However, the impact of liver injury on the host's ability to control bacteremia and morbidity in sepsis is not well understood. Leukocyte recruitment and activation lead to cytokine and chemokine release, which, in turn, trigger hepatocellular injury and elevate nucleotide levels in the extracellular milieu. P2Y2 purinergic receptors, G protein-coupled and activated by extracellular ATP/UTP, are expressed at the cell surface of hepatocytes and nonparenchymal cells. We sought to determine whether P2Y2 purinergic receptor function is necessary for the maladaptive host response to bacterial infection and endotoxin-mediated inflammatory liver injury and mortality in mice. We report that P2Y2 purinergic receptor knockout mice (P2Y2-/-) had attenuated inflammation and liver injury, with improved survival in response to LPS/galactosamine (LPS/GalN; inflammatory liver injury) and cecal ligation and puncture (CLP; polymicrobial sepsis). P2Y2-/- livers had attenuated c-Jun NH2-terminal kinase activation, matrix metallopeptidase-9 expression, and hepatocyte apoptosis in response to LPS/GalN and attenuated inducible nitric oxide synthase and nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing 3 protein expression in response to CLP. Implicating liver injury in the disruption of amino acid homeostasis, CLP led to lower serum arginine and higher bacterial load and morbidity in the WT mice, whereas serum arginine levels were comparable to sham-operated controls in P2Y2-/- mice, which had attenuated bacteremia and improved survival. Collectively, our studies highlight the pathophysiological relevance of P2Y2 purinergic receptor function in inflammatory liver injury and dysregulation of systemic amino acid homeostasis with implications for sepsis-associated immune dysfunction and morbidity in mice.NEW & NOTEWORTHY Our studies provide experimental evidence for P2Y2 purinergic receptor-mediated potentiation of inflammatory liver injury, morbidity, and mortality, in two well-established animal models of inflammatory liver injury. Our findings highlight the potential to target P2Y2 purinergic signaling to attenuate the induction of "cytokine storm" and prevent its deleterious consequences on liver function, systemic amino acid homeostasis, host response to bacterial infection, and sepsis-associated morbidity and mortality.
Collapse
Affiliation(s)
- Athis R Arunachalam
- Neonatology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Sanju S Samuel
- Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Arunmani Mani
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Janielle P Maynard
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Kelsey M Stayer
- Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Eric Dybbro
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Subapradha Narayanan
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Aalekhya Biswas
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Saliha Pathan
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Krishnakant Soni
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Abu Hena Mostafa Kamal
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States
| | | | - Nagireddy Putluri
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States
| | - Moreshwar S Desai
- Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| | - Sundararajah Thevananther
- Section of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
An Q, Yue G, Yang X, Lou J, Shan W, Ding J, Jin Z, Hu Y, Du Q, Liao Q, Xie R, Xu J. Pathophysiological Role of Purinergic P2X Receptors in Digestive System Diseases. Front Physiol 2022; 12:781069. [PMID: 35002763 PMCID: PMC8740087 DOI: 10.3389/fphys.2021.781069] [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: 09/22/2021] [Accepted: 12/01/2021] [Indexed: 11/16/2022] Open
Abstract
P2X receptors (P2XRs) are trimeric, non-selective cation channels activated by extracellular ATP and widely distributed in the digestive system. P2XRs have an important role in the physiological function of the digestive system, such as neurotransmission, ion transports, proliferation and apoptosis, muscle contraction, and relaxation. P2XRs can be involved in pain mechanisms both centrally and in the periphery and confirmed the association of P2XRs with visceral pain. In the periphery, ATP can be released as a result of tissue injury, visceral distension, or sympathetic activation and can excite nociceptive primary afferents by acting at homomeric P2X(3)R or heteromeric P2X(2/3)R. Thus, peripheral P2XRs, and homomeric P2X(3) and/or heteromeric P2X(2/3)R in particular, constitute attractive targets for analgesic drugs. Recently studies have shown that P2XRs have made significant advances in inflammation and cancer. P2X7R mediates NLRP3 inflammasome activation, cytokine and chemokine release, T lymphocyte survival and differentiation, transcription factor activation, and cell death. The P2X7R is a potent stimulant of inflammation and immunity and a promoter of cancer cell growth. This makes P2X7R an appealing target for anti-inflammatory and anti-cancer therapy. It is believed that with the further study of P2XRs and its subtypes, P2XRs and its specific antagonists will be expected to be widely used in the treatment of human digestive diseases in the future.
Collapse
Affiliation(s)
- Qimin An
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Gengyu Yue
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Xiaoxu Yang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Jun Lou
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Weixi Shan
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Jianhong Ding
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Zhe Jin
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Yanxia Hu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Qian Du
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Qiushi Liao
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Rui Xie
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| | - Jingyu Xu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,The Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical University, Zunyi, China
| |
Collapse
|
7
|
Desplat A, Penalba V, Gros E, Parpaite T, Coste B, Delmas P. Piezo1-Pannexin1 complex couples force detection to ATP secretion in cholangiocytes. J Gen Physiol 2021; 153:212722. [PMID: 34694360 PMCID: PMC8548913 DOI: 10.1085/jgp.202112871] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 08/17/2021] [Indexed: 01/07/2023] Open
Abstract
Cholangiocytes actively contribute to the final composition of secreted bile. These cells are exposed to abnormal mechanical stimuli during obstructive cholestasis, which has a deep impact on their function. However, the effects of mechanical insults on cholangiocyte function are not understood. Combining gene silencing and pharmacological assays with live calcium imaging, we probed molecular candidates essential for coupling mechanical force to ATP secretion in mouse cholangiocytes. We show that Piezo1 and Pannexin1 are necessary for eliciting the downstream effects of mechanical stress. By mediating a rise in intracellular Ca2+, Piezo1 acts as a mechanosensor responsible for translating cell swelling into activation of Panx1, which triggers ATP release and subsequent signal amplification through P2X4R. Co-immunoprecipitation and pull-down assays indicated physical interaction between Piezo1 and Panx1, which leads to stable plasma membrane complexes. Piezo1–Panx1–P2X4R ATP release pathway could be reconstituted in HEK Piezo1 KO cells. Thus, our data suggest that Piezo1 and Panx1 can form a functional signaling complex that controls force-induced ATP secretion in cholangiocytes. These findings may foster the development of novel therapeutic strategies for biliary diseases.
Collapse
Affiliation(s)
- Angélique Desplat
- Aix-Marseille-Université, Centre National de la Recherche Scientifique, Laboratoire de Neurosciences Cognitives, UMR 7291, CS80011, Marseille, France
| | - Virginie Penalba
- Aix-Marseille-Université, Centre National de la Recherche Scientifique, Laboratoire de Neurosciences Cognitives, UMR 7291, CS80011, Marseille, France
| | - Emeline Gros
- Aix-Marseille-Université, Centre National de la Recherche Scientifique, Laboratoire de Neurosciences Cognitives, UMR 7291, CS80011, Marseille, France
| | - Thibaud Parpaite
- Aix-Marseille-Université, Centre National de la Recherche Scientifique, Laboratoire de Neurosciences Cognitives, UMR 7291, CS80011, Marseille, France
| | - Bertrand Coste
- Aix-Marseille-Université, Centre National de la Recherche Scientifique, Laboratoire de Neurosciences Cognitives, UMR 7291, CS80011, Marseille, France
| | - Patrick Delmas
- Aix-Marseille-Université, Centre National de la Recherche Scientifique, Laboratoire de Neurosciences Cognitives, UMR 7291, CS80011, Marseille, France
| |
Collapse
|
8
|
Vartak N, Drasdo D, Geisler F, Itoh T, P J Oude Elferink R, van de Graaf SFJ, Chiang J, Keitel V, Trauner M, Jansen P, Hengstler JG. On the Mechanisms of Biliary Flux. Hepatology 2021; 74:3497-3512. [PMID: 34164843 DOI: 10.1002/hep.32027] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/18/2021] [Accepted: 06/07/2021] [Indexed: 12/15/2022]
Abstract
Since the late 1950s, transport of bile in the liver has been described by the "osmotic concept," according to which bile flows into the canaliculi toward the ducts, countercurrent to the blood flow in the sinusoids. However, because of the small size of canaliculi, it was so far impossible to observe, let alone to quantify this process. Still, "osmotic canalicular flow" was a sufficient and plausible explanation for the clearance characteristics of a wide variety of choleretic compounds excreted in bile. Imaging techniques have now been established that allow direct flux analysis in bile canaliculi of the intact liver in living organisms. In contrast to the prevailing osmotic concept these analyses strongly suggest that the transport of small molecules in canalicular bile is diffusion dominated, while canalicular flow is negligibly small. In contrast, with the same experimental approach, it could be shown that in the interlobular ducts, diffusion is augmented by flow. Thus, bile canaliculi can be compared to a standing water zone that is connected to a river. The seemingly subtle difference between diffusion and flow is of relevance for therapy of a wide range of liver diseases including cholestasis and NAFLD. Here, we incorporated the latest findings on canalicular solute transport, and align them with extant knowledge to present an integrated and explanatory framework of bile flux that will undoubtedly be refined further in the future.
Collapse
Affiliation(s)
- Nachiket Vartak
- Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
| | - Dirk Drasdo
- National Institute for Research in Digital Science and Technology, Paris, France
| | - Fabian Geisler
- Clinic and Polyclinic for Internal Medicine II, Kinikum Rechts der Isar, Technical University Munich, Munich, Germany
| | - Tohru Itoh
- Institute for Quantitative Biosciences, the University of Tokyo, Tokyo, Japan
| | - Ronald P J Oude Elferink
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Stan F J van de Graaf
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - John Chiang
- North-East Ohio Medical University, Rootstown, OH, USA
| | - Verena Keitel
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, University Hospital Düsseldorf, Medical Faculty at Heinrich-Heine-University, Düsseldorf, Germany
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Peter Jansen
- Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
| |
Collapse
|
9
|
The bile acid-sensitive ion channel (BASIC) mediates bile acid-dependent currents in bile duct epithelial cells. Pflugers Arch 2021; 473:1841-1850. [PMID: 34549327 PMCID: PMC8599227 DOI: 10.1007/s00424-021-02622-2] [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: 02/21/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 11/17/2022]
Abstract
The bile acid-sensitive ion channel (BASIC) is a member of the Deg/ENaC family of ion channels that is activated by bile acids. Despite the identification of cholangiocytes in the liver and unipolar brush cells in the cerebellum as sites of expression, the physiological function of BASIC in these cell types is not yet understood. Here we used a cholangiocyte cell line, normal rat cholangiocytes (NRCs), which expresses BASIC to study the role of the channel in epithelial transport using Ussing chamber experiments. Apical application of bile acids induced robust and transient increases in transepithelial currents that were carried by Na+ and partly blocked by the BASIC inhibitor diminazene. Genetic ablation of the BASIC gene in NRC using a CRISPR-cas9 approach resulted in a decrease of the bile acid-mediated response that matched the diminazene-sensitive current in NRC WT cells, suggesting that cholangiocytes respond to bile acids with a BASIC-mediated Na+ influx. Taken together, we have identified BASIC as a component of the cholangiocyte transport machinery, which might mediate a bile acid-dependent modification of the bile and thus control bile flux and composition.
Collapse
|
10
|
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: 15] [Impact Index Per Article: 3.8] [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.
Collapse
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
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Agarwal T, Subramanian B, Maiti TK. Liver Tissue Engineering: Challenges and Opportunities. ACS Biomater Sci Eng 2019; 5:4167-4182. [PMID: 33417776 DOI: 10.1021/acsbiomaterials.9b00745] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Liver tissue engineering aims at the possibility of reproducing a fully functional organ for the treatment of acute and chronic liver disorders. Approaches in this field endeavor to replace organ transplantation (gold standard treatment for liver diseases in a clinical setting) with in vitro developed liver tissue constructs. However, the complexity of the liver microarchitecture and functionality along with the limited supply of cellular components of the liver pose numerous challenges. This review provides a comprehensive outlook onto how the physicochemical, mechanobiological, and spatiotemporal aspects of the substrates could be tuned to address current challenges in the field. We also highlight the strategic advancements made in the field so far for the development of artificial liver tissue. We further showcase the currently available prototypes in research and clinical trials, which shows the hope for the future of liver tissue engineering.
Collapse
|
13
|
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: 36] [Impact Index Per Article: 6.0] [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).
Collapse
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
| |
Collapse
|
14
|
Trampert DC, Nathanson MH. Regulation of bile secretion by calcium signaling in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1761-1770. [PMID: 29787781 DOI: 10.1016/j.bbamcr.2018.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/12/2018] [Accepted: 05/16/2018] [Indexed: 12/15/2022]
Abstract
Calcium (Ca2+) signaling controls secretion in many types of cells and tissues. In the liver, Ca2+ regulates secretion in both hepatocytes, which are responsible for primary formation of bile, and cholangiocytes, which line the biliary tree and further condition the bile before it is secreted. Cholestatic liver diseases, which are characterized by impaired bile secretion, may result from impaired Ca2+ signaling mechanisms in either hepatocytes or cholangiocytes. This review will discuss the Ca2+ signaling machinery and mechanisms responsible for regulation of secretion in both hepatocytes and cholangiocytes, and the pathophysiological changes in Ca2+ signaling that can occur in each of these cell types to result in cholestasis.
Collapse
Affiliation(s)
- David C Trampert
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8019, USA
| | - Michael H Nathanson
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8019, USA.
| |
Collapse
|
15
|
Song Y, Liu C, Liu X, Trottier J, Beaudoin M, Zhang L, Pope C, Peng G, Barbier O, Zhong X, Li L, Wang L. H19 promotes cholestatic liver fibrosis by preventing ZEB1-mediated inhibition of epithelial cell adhesion molecule. Hepatology 2017; 66:1183-1196. [PMID: 28407375 PMCID: PMC5605402 DOI: 10.1002/hep.29209] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/16/2017] [Accepted: 04/05/2017] [Indexed: 12/11/2022]
Abstract
UNLABELLED Based on our recent finding that disruption of bile acid (BA) homeostasis in mice results in the induction of hepatic long noncoding RNA H19 expression, we sought to elucidate the role of H19 in cholestatic liver fibrosis. Hepatic overexpression of H19RNA augmented bile duct ligation (BDL)-induced liver fibrosis, which was accompanied by the elevation of serum alanine aminotransferase, aspartate aminotransferase, bilirubin, and BA levels. Multiple genes related to liver fibrosis, inflammation, and biliary hyperplasia were increased in H19-BDL versus null-BDL mice, whereas genes in BA synthesis were decreased. Livers and spleens of H19-BDL mice showed significant enrichment of CD3+γδ+, interleukin-4, and interleukin-17 producing CD4+ and CD8+ immune cell populations. H19 down-regulated hepatic zinc finger E-box-binding homeobox 1 (ZEB1) but up-regulated epithelial cell adhesion molecule (EpCAM) and SRY (sex determining region Y)-box 9 expression. Mechanistically, ZEB1 repressed EpCAM promoter activity and gene transcription. H19RNA impeded ZEB1's inhibitory action by interacting with ZEB1 protein to prevent its binding to the EpCAM promoter. Hepatic overexpression of ZEB1 or knockdown of EpCAM diminished H19-induced fibrosis; the latter was also prevented in H19-/- mice. H19RNA was markedly induced by bile acids in mouse small cholangiocytes and to a lesser extent in mouse large cholangiocytes. The up-regulation of H19RNA and EpCAM correlated positively with the down-regulation of ZEB1 in primary sclerosing cholangitis and primary biliary cirrhosis liver specimens. CONCLUSION The activation of hepatic H19RNA promoted cholestatic liver fibrosis in mice through the ZEB1/EpCAM signaling pathway. (Hepatology 2017;66:1183-1196).
Collapse
Affiliation(s)
- Yongfeng Song
- Department of Physiology and Neurobiology, and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269,Department of Endocrinology and metabolism, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong 250021, China
| | - Chune Liu
- Department of Physiology and Neurobiology, and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Xia Liu
- Division of Infectious Diseases, Allergy & Immunology, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Jocelyn Trottier
- Laboratory of Molecular Pharmacology, CHU-Québec Research Centre and Faculty of Pharmacy, Laval University, Québec, QC, Canada
| | - Michele Beaudoin
- Department of Physiology and Neurobiology, and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Li Zhang
- Department of Physiology and Neurobiology, and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Chad Pope
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, CT 06269
| | - Guangyong Peng
- Division of Infectious Diseases, Allergy & Immunology, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Olivier Barbier
- Laboratory of Molecular Pharmacology, CHU-Québec Research Centre and Faculty of Pharmacy, Laval University, Québec, QC, Canada
| | - Xiaobo Zhong
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, CT 06269
| | - Linheng Li
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Li Wang
- Department of Physiology and Neurobiology, and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269,Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, CT 06520,Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516,School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China,Correspondence: Li Wang, Ph.D., 75 North Eagleville Rd., U3156, Storrs, CT 06269. ; Tel: 860-486-0857; Fax: 860-486-3303
| |
Collapse
|
16
|
Cell culture: complications due to mechanical release of ATP and activation of purinoceptors. Cell Tissue Res 2017; 370:1-11. [PMID: 28434079 PMCID: PMC5610203 DOI: 10.1007/s00441-017-2618-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/21/2017] [Indexed: 12/11/2022]
Abstract
There is abundant evidence that ATP (adenosine 5′-triphosphate) is released from a variety of cultured cells in response to mechanical stimulation. The release mechanism involved appears to be a combination of vesicular exocytosis and connexin and pannexin hemichannels. Purinergic receptors on cultured cells mediate both short-term purinergic signalling of secretion and long-term (trophic) signalling such as proliferation, migration, differentiation and apoptosis. We aim in this review to bring to the attention of non-purinergic researchers using tissue culture that the release of ATP in response to mechanical stress evoked by the unavoidable movement of the cells acting on functional purinergic receptors on the culture cells is likely to complicate the interpretation of their data.
Collapse
|
17
|
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).
Collapse
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
| | | |
Collapse
|
18
|
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.
Collapse
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;
| |
Collapse
|
19
|
Weerachayaphorn J, Amaya MJ, Spirli C, Chansela P, Mitchell KA, Ananthanarayanan M, Nathanson MH. Nuclear Factor, Erythroid 2-Like 2 Regulates Expression of Type 3 Inositol 1,4,5-Trisphosphate Receptor and Calcium Signaling in Cholangiocytes. Gastroenterology 2015; 149:211-222.e10. [PMID: 25796361 PMCID: PMC4478166 DOI: 10.1053/j.gastro.2015.03.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 02/27/2015] [Accepted: 03/13/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Most cholestatic disorders are caused by defects in cholangiocytes. The type 3 isoform of the inositol 1,4,5-trisphosphate receptor (ITPR3) is the most abundant intracellular calcium release channel in cholangiocytes. ITPR3 is required for bicarbonate secretion by bile ducts, and its expression is reduced in intrahepatic bile ducts of patients with cholestatic disorders. We investigated whether the nuclear factor, erythroid 2-like 2 (NFE2L2 or NRF2), which is sensitive to oxidative stress, regulates expression of ITPR3. METHODS The activity of the ITPR3 promoter was measured in normal human cholangiocyte (NHC) cells and primary mouse cholangiocytes. Levels of ITPR3 protein and messenger RNA were examined by immunoblot and polymerase chain reaction analyses, respectively. ITPR3 activity was determined by measuring calcium signaling in normal human cholangiocyte cells and secretion in isolated bile duct units. Levels of NRF2 were measured in liver tissues from rats with cholestasis (induced by administration of α-napthylisothiocyanate) and from patients with biliary diseases. RESULTS We identified a musculo-aponeurotic fibrosarcoma recognition element in the promoter of ITPR3 that bound NRF2 directly in NHC cells and mouse cholangiocytes. Increasing binding of NRF2 at this site resulted in chromatin remodeling that reduced promoter activity. Mutant forms of the musculo-aponeurotic fibrosarcoma recognition element did not bind NRF2. Activation of NRF2 with quercetin or by oxidative stress reduced expression of ITPR3 and calcium signaling in NHC cells; quercetin also reduced secretion by bile duct units isolated from rats. Knockdown of NRF2 with small interfering RNAs restored expression and function of ITPR3 in NHC cells incubated with quercetin. Bile ducts from rats with cholestasis and patients with cholangiopathic disorders expressed higher levels of NRF2 and lower levels of ITPR3 than ducts from control rats or patients with other liver disorders. CONCLUSIONS The transcription factor NRF2 binds to the promoter of ITPR3 to inhibit its expression in cholangiocytes, leading to reduced calcium signaling and bile duct secretion. This could be a mechanism by which oxidative stress inhibits these processes and contributes to cholangiopathies.
Collapse
Affiliation(s)
- Jittima Weerachayaphorn
- Liver Center, Yale University School of Medicine, New Haven, Connecticut, USA,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Maria Jimena Amaya
- Liver Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Carlo Spirli
- Liver Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Piyachat Chansela
- Department of Anatomy, Phramongkutklao College of Medicine, Bangkok, Thailand
| | - Kisha A. Mitchell
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | - Michael H. Nathanson
- Liver Center, Yale University School of Medicine, New Haven, Connecticut, USA,Corresponding Author: Michael H. Nathanson MD., PhD., Department of Medicine, Section of Digestive Diseases, Yale University School of Medicine, 333 Cedar Street, TAC S241D, New Haven, CT, 06519 USA, Tel: (203)-785-7312, Fax: (203)-785-7273,
| |
Collapse
|
20
|
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.
Collapse
|
21
|
Godoy V, Banales JM, Medina JF, Pastor-Anglada M. Functional crosstalk between the adenosine transporter CNT3 and purinergic receptors in the biliary epithelia. J Hepatol 2014; 61:1337-43. [PMID: 25034758 DOI: 10.1016/j.jhep.2014.06.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/17/2014] [Accepted: 06/27/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND & AIMS Both hepatocytes and cholangiocytes release ATP into the bile, where it acts as a potent autocrine/paracrine stimulus that activates biliary secretory mechanisms. ATP is known to be metabolized into multiple breakdown products, ultimately yielding adenosine. However, the elements implicated in the adenosine-dependent purinergic regulation of cholangiocytes are not known. METHODS Normal rat cholangiocytes (NRCs) were used to study the expression of adenosine receptors and transporters and their functional interactions at the apical and basolateral membrane domains of polarized cholangiocytes. RESULTS We found that: (1) cholangiocytes exclusively express two concentrative nucleoside transporters (CNT) known to be efficient adenosine carriers: CNT3, located at the apical membrane, and CNT2, located at apical and basolateral membrane domains; (2) in both domains, NRCs also express the high affinity adenosine receptor A2A, which modulated the activity of apical CNT3 in a domain-specific manner; (3) the regulation exerted by A2A on CNT3 was dependent upon the cAMP/PKA/ERK/CREB axis, intracellular trafficking mechanisms and AMPK phosphorylation; (4) secretin increased the activity of the apically-located CNT3, and promoted additional basolateral CNT3-related activity; and (5) extracellular ATP (a precursor of adenosine) was able to exert an inhibitory effect on the apical activity of both CNT3 and CNT2. CONCLUSIONS This study uncovered the functional expression of nucleoside transporters in cholangiocytes and provides evidence for direct crosstalks between adenosine transporters and receptors for adenosine and its natural extracellular precursor, ATP. Our data anticipate the possibility of adenosine playing a major role in the physiopathology of the biliary epithelia.
Collapse
Affiliation(s)
- Valeria Godoy
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain
| | - Jesús M Banales
- Department of Liver Diseases, Biodonostia Research Institute (Donostia University Hospital), IKERBASQUE (Basque Foundation for Science), University of Basque Country (UPV/EHU), San Sebastian, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain
| | - Juan F Medina
- Molecular Genetics, Division of Gene Therapy and Hepatology, School of Medicine and CIMA of the University of Navarra, Pamplona, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain
| | - Marçal Pastor-Anglada
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biology, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain; National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Spain.
| |
Collapse
|
22
|
Tackett BC, Sun H, Mei Y, Maynard JP, Cheruvu S, Mani A, Hernandez-Garcia A, Vigneswaran N, Karpen SJ, Thevananther S. P2Y2 purinergic receptor activation is essential for efficient hepatocyte proliferation in response to partial hepatectomy. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1073-87. [PMID: 25301185 PMCID: PMC4254960 DOI: 10.1152/ajpgi.00092.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 09/30/2014] [Indexed: 01/31/2023]
Abstract
Extracellular nucleotides via activation of P2 purinergic receptors influence hepatocyte proliferation and liver regeneration in response to 70% partial hepatectomy (PH). Adult hepatocytes express multiple P2Y (G protein-coupled) and P2X (ligand-gated ion channels) purinergic receptor subtypes. However, the identity of key receptor subtype(s) important for efficient hepatocyte proliferation in regenerating livers remains unknown. To evaluate the impact of P2Y2 purinergic receptor-mediated signaling on hepatocyte proliferation in regenerating livers, wild-type (WT) and P2Y2 purinergic receptor knockout (P2Y2-/-) mice were subjected to 70% PH. Liver tissues were analyzed for activation of early events critical for hepatocyte priming and subsequent cell cycle progression. Our findings suggest that early activation of p42/44 ERK MAPK (5 min), early growth response-1 (Egr-1) and activator protein-1 (AP-1) DNA-binding activity (30 min), and subsequent hepatocyte proliferation (24-72 h) in response to 70% PH were impaired in P2Y2-/- mice. Interestingly, early induction of cytokines (TNF-α, IL-6) and cytokine-mediated signaling (NF-κB, STAT-3) were intact in P2Y2-/- remnant livers, uncovering the importance of cytokine-independent and nucleotide-dependent early priming events critical for subsequent hepatocyte proliferation in regenerating livers. Hepatocytes isolated from the WT and P2Y2-/- mice were treated with ATP or ATPγS for 5-120 min and 12-24 h. Extracellular ATP alone, via activation of P2Y2 purinergic receptors, was sufficient to induce ERK phosphorylation, Egr-1 protein expression, and key cyclins and cell cycle progression of hepatocytes in vitro. Collectively, these findings highlight the functional significance of P2Y2 purinergic receptor activation for efficient hepatocyte priming and proliferation in response to PH.
Collapse
Affiliation(s)
- Bryan C Tackett
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas; Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas
| | - Hongdan Sun
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas
| | - Yu Mei
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas
| | - Janielle P Maynard
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas; Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas
| | - Sayuri Cheruvu
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas
| | - Arunmani Mani
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas
| | | | - Nadarajah Vigneswaran
- Department of Diagnostic Sciences, University of Texas Dental Branch in Houston, Houston, Texas
| | - Saul J Karpen
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas; Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas
| | - Sundararajah Thevananther
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Texas Children's Liver Center, Houston, Texas; Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, Texas;
| |
Collapse
|
23
|
Afroze S, Meng F, Jensen K, McDaniel K, Rahal K, Onori P, Gaudio E, Alpini G, Glaser SS. The physiological roles of secretin and its receptor. ANNALS OF TRANSLATIONAL MEDICINE 2014; 1:29. [PMID: 25332973 DOI: 10.3978/j.issn.2305-5839.2012.12.01] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 12/13/2012] [Indexed: 12/19/2022]
Abstract
Secretin is secreted by S cells in the small intestine and affects the function of a number of organ systems. Secretin receptors (SR) are expressed in the basolateral domain of several cell types. In addition to regulating the secretion of a number of epithelia (e.g., in the pancreas and biliary epithelium in the liver), secretin exerts trophic effects in several cell types. In this article, we will provide a comprehensive review on the multiple roles of secretin and SR signaling in the regulation of epithelial functions in various organ systems with particular emphasis in the liver. We will discuss the role of secretin and its receptor in health and biliary disease pathogenesis. Finally, we propose future areas of research for the further evaluation of the secretin/secretin receptor axis in liver pathophysiology.
Collapse
Affiliation(s)
- Syeda Afroze
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Fanyin Meng
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Kendal Jensen
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Kelly McDaniel
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Kinan Rahal
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Paolo Onori
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Eugenio Gaudio
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Gianfranco Alpini
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| | - Shannon S Glaser
- 1 Department of Medicine, Division Gastroenterology, 2 Research, Central Texas Veterans Health Care System, 3 Scott & White Digestive Disease Research Center, Scott & White, and Texas A&M Health Science Center, College of Medicine, Temple, TX 76504, USA ; 4 Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 5 Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, University Sapienza, Rome, Italy
| |
Collapse
|
24
|
Franchitto A, Onori P, Renzi A, Carpino G, Mancinelli R, Alvaro D, Gaudio E. Recent advances on the mechanisms regulating cholangiocyte proliferation and the significance of the neuroendocrine regulation of cholangiocyte pathophysiology. ANNALS OF TRANSLATIONAL MEDICINE 2014; 1:27. [PMID: 25332971 DOI: 10.3978/j.issn.2305-5839.2012.10.03] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/15/2012] [Indexed: 12/14/2022]
Abstract
Cholangiocytes are epithelial cells lining the biliary epithelium. Cholangiocytes play several key roles in the modification of ductal bile and are also the target cells in chronic cholestatic liver diseases (i.e., cholangiopathies) such as PSC, PBC, polycystic liver disease (PCLD) and cholangiocarcinoma (CCA). During these pathologies, cholangiocytes (which in normal condition are in a quiescent state) begin to proliferate acquiring phenotypes of neuroendocrine cells, and start secreting different cytokines, growth factors, neuropeptides, and hormones to modulate cholangiocytes proliferation and interaction with the surrounding environment, trying to reestablish the balance between proliferation/loss of cholangiocytes for the maintenance of biliary homeostasis. The purpose of this review is to summarize the recent findings on the mechanisms regulating cholangiocyte proliferation and the significance of the neuroendocrine regulation of cholangiocyte pathophysiology. To clarify the mechanisms of action of these factors we will provide new potential strategies for the management of chronic liver diseases.
Collapse
Affiliation(s)
- Antonio Franchitto
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| | - Paolo Onori
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| | - Anastasia Renzi
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| | - Guido Carpino
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| | - Romina Mancinelli
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| | - Domenico Alvaro
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| | - Eugenio Gaudio
- 1 Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, University of Rome "Sapienza", Rome, Italy ; 2 Eleonora Lorillard Spencer-Cenci Foundation, Rome, Italy ; 3 Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy ; 4 Department of Health Science, University of Rome "Foro Italico", Italy ; 5 Department of Medico-Surgical Sciences and Biotechnologies, Polo Pontino, Sapienza, University of Rome "Sapienza", Rome, Italy
| |
Collapse
|
25
|
Abstract
Primary biliary cirrhosis (PBC) is an autoimmune liver disease characterized by selective destruction of intrahepatic cholangiocytes. Mechanisms underlying the development and progression of the disease are still controversial and largely undefined. Evidence suggests that PBC results from an articulated immunologic response against an immunodominant mitochondrial autoantigen, the E2 component of the pyruvate dehydrogenase complex (PDC-E2); characteristics of the disease are also the presence of disease-specific antimitochondrial autoantibodies (AMAs) and autoreactive CD4 and CD8 T cells. Recent evidence suggests that cholangiocytes show specific immunobiological features that are responsible for the selective targeting of those cells by the immune system. The immune reaction in PBC selectively targets small sized, intrahepatic bile ducts; although a specific reason for that has not been defined yet, it has been established that the biliary epithelium displays a unique heterogeneity, for which the physiological and pathophysiological features of small and large cholangiocytes significantly differ. In this review article, the authors provide a critical overview of the current evidence on the role of cholangiocytes in the immune-mediated destruction of the biliary tree that characterizes PBC.
Collapse
Affiliation(s)
- Ana Lleo
- Liver Unit and Center for Autoimmune Liver Diseases, Humanitas Clinical and Research Center, Rozzano (MI), Italy
| | - Luca Maroni
- Clinic of Gastroenterology and Hepatology, Università Politecnica delle Marche, Ancona, Italy
| | - Shannon Glaser
- Research, Central Texas Veterans Health Care System, S and W and Texas A and M System Health Science Center, College of Medicine, Temple, Texas,Scott & White Digestive Disease Research Center, S and W and Texas A and M System Health Science Center, College of Medicine, Temple, Texas,Department of Medicine, Division Gastroenterology, S and W and Texas A and M System Health Science Center, College of Medicine, Temple, Texas
| | - Gianfranco Alpini
- Research, Central Texas Veterans Health Care System, S and W and Texas A and M System Health Science Center, College of Medicine, Temple, Texas,Scott & White Digestive Disease Research Center, S and W and Texas A and M System Health Science Center, College of Medicine, Temple, Texas,Department of Medicine, Division Gastroenterology, S and W and Texas A and M System Health Science Center, College of Medicine, Temple, Texas
| | - Marco Marzioni
- Clinic of Gastroenterology and Hepatology, Università Politecnica delle Marche, Ancona, Italy
| |
Collapse
|
26
|
Abstract
Hepatic myofibroblasts are activated in response to chronic liver injury of any etiology to produce a fibrous scar. Despite extensive studies, the origin of myofibroblasts in different types of fibrotic liver diseases is unresolved. To identify distinct populations of myofibroblasts and quantify their contribution to hepatic fibrosis of two different etiologies, collagen-α1(I)-GFP mice were subjected to hepatotoxic (carbon tetrachloride; CCl4) or cholestatic (bile duct ligation; BDL) liver injury. All myofibroblasts were purified by flow cytometry of GFP(+) cells and then different subsets identified by phenotyping. Liver resident activated hepatic stellate cells (aHSCs) and activated portal fibroblasts (aPFs) are the major source (>95%) of fibrogenic myofibroblasts in these models of liver fibrosis in mice. As previously reported using other methodologies, hepatic stellate cells (HSCs) are the major source of myofibroblasts (>87%) in CCl4 liver injury. However, aPFs are a major source of myofibroblasts in cholestatic liver injury, contributing >70% of myofibroblasts at the onset of injury (5 d BDL). The relative contribution of aPFs decreases with progressive injury, as HSCs become activated and contribute to the myofibroblast population (14 and 20 d BDL). Unlike aHSCs, aPFs respond to stimulation with taurocholic acid and IL-25 by induction of collagen-α1(I) and IL-13, respectively. Furthermore, BDL-activated PFs express high levels of collagen type I and provide stimulatory signals to HSCs. Gene expression analysis identified several novel markers of aPFs, including a mesothelial-specific marker mesothelin. PFs may play a critical role in the pathogenesis of cholestatic liver fibrosis and, therefore, serve as an attractive target for antifibrotic therapy.
Collapse
|
27
|
Burnstock G. Purinergic signalling in the gastrointestinal tract and related organs in health and disease. Purinergic Signal 2014; 10:3-50. [PMID: 24307520 PMCID: PMC3944042 DOI: 10.1007/s11302-013-9397-9] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/04/2023] Open
Abstract
Purinergic signalling plays major roles in the physiology and pathophysiology of digestive organs. Adenosine 5'-triphosphate (ATP), together with nitric oxide and vasoactive intestinal peptide, is a cotransmitter in non-adrenergic, non-cholinergic inhibitory neuromuscular transmission. P2X and P2Y receptors are widely expressed in myenteric and submucous enteric plexuses and participate in sympathetic transmission and neuromodulation involved in enteric reflex activities, as well as influencing gastric and intestinal epithelial secretion and vascular activities. Involvement of purinergic signalling has been identified in a variety of diseases, including inflammatory bowel disease, ischaemia, diabetes and cancer. Purinergic mechanosensory transduction forms the basis of enteric nociception, where ATP released from mucosal epithelial cells by distension activates nociceptive subepithelial primary afferent sensory fibres expressing P2X3 receptors to send messages to the pain centres in the central nervous system via interneurons in the spinal cord. Purinergic signalling is also involved in salivary gland and bile duct secretion.
Collapse
Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
| |
Collapse
|
28
|
Amaya MJ, Nathanson MH. Calcium signaling and the secretory activity of bile duct epithelia. Cell Calcium 2014; 55:317-24. [PMID: 24612866 DOI: 10.1016/j.ceca.2014.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/03/2014] [Accepted: 02/04/2014] [Indexed: 12/20/2022]
Abstract
Cytosolic calcium (Cai(2+)) is a second messenger that is important for the regulation of secretion in many types of tissues. Bile duct epithelial cells, or cholangiocytes, are polarized epithelia that line the biliary tree in liver and are responsible for secretion of bicarbonate and other solutes into bile. Cai(2+) signaling plays an important role in the regulation of secretion by cholangiocytes, and this review discusses the machinery involved in the formation of Ca(2+) signals in cholangiocytes, along with the evidence that these signals regulate ductular secretion. Finally, this review discusses the evidence that impairments in cholangiocyte Ca(2+) signaling play a primary role in the pathogenesis of cholestatic disorders, in which hepatic bile secretion is impaired.
Collapse
Affiliation(s)
- Maria Jimena Amaya
- Section of Digestive Diseases, Department of Internal Medicine, Yale University, 333 Cedar Street, PO Box 208019, New Haven, CT 06520-8019, USA
| | - Michael H Nathanson
- Section of Digestive Diseases, Department of Internal Medicine, Yale University, 333 Cedar Street, PO Box 208019, New Haven, CT 06520-8019, USA.
| |
Collapse
|
29
|
Seo J, Osorio JS, Schmitt E, Corrêa MN, Bertoni G, Trevisi E, Loor JJ. Hepatic purinergic signaling gene network expression and its relationship with inflammation and oxidative stress biomarkers in blood from peripartal dairy cattle. J Dairy Sci 2013; 97:861-73. [PMID: 24359819 DOI: 10.3168/jds.2013-7379] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/05/2013] [Indexed: 01/08/2023]
Abstract
The liver plays a central role in allowing dairy cattle to make a successful transition into lactation. In liver, as in other tissues, extracellular nucleotides and nucleosides trigger cellular responses through adenosine and ATP receptors. Adenosine triphosphate and certain nucleotides serve as signals that can heighten purinergic receptor activation in several pathologic processes. We evaluated the mRNA expression of genes associated with the purinergic signaling network in liver tissue during the peripartal period. Seven multiparous Holstein cows were dried off at d -50 relative to expected parturition and fed a controlled-energy diet (net energy for lactation=1.24 Mcal/kg of DM) for ad libitum intake during the entire dry period. After calving, all cows were fed a common lactation diet (net energy for lactation=1.65 Mcal/kg of DM) until 30 DIM. Biopsies of liver were harvested at d -10, 7, and 21 for mRNA expression of 9 purinergic receptors, 7 ATP and adenosine transport channels, and 10 enzymes associated with ATP hydrolysis. Blood collected at d -21, -10, 7, 14, and 21 was used to measure concentrations of inflammation and oxidative stress biomarkers. The expression of type 1 purinergic receptors (ADORA2A and ADORA3), several nucleoside hydrolases [ectonucleoside triphosphate diphosphohydrolase 7 (ENTPD7), ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2), ENPP3, and adenosine deaminase (ADA)], and a type 2 purinergic receptor (P2RX7) was downregulated after calving. In contrast, the expression of type 2 purinergic receptors (P2RX4 and PR2Y11), an ATP release channel (gap junction hemichannel GJB1), and an adenosine uptake protein (SLC29A1) followed the opposite response, increasing after calving and remaining elevated through 21 d. Haptoglobin, ceruloplasmin, and reactive oxygen metabolite concentrations increased gradually from d -21 d through at least d 7. The opposite response was observed for albumin, paraoxonase, α-tocopherol, and nitric oxide, which decreased gradually to a nadir at 7 and 14 d. Our results suggest that alterations after calving of the expression of hepatic purinergic signaling genes could be functionally important because in nonruminants, they play roles in bile formation, glucose metabolism, cholesterol uptake, inflammation, and steatosis. The correlation analysis provided evidence of a link between purinergic signaling genes and biomarkers of inflammation and oxidative stress.
Collapse
Affiliation(s)
- J Seo
- Department of Agricultural Biotechnology, Research Institute for Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Daehak-dong, Kwanak-gu, Seoul 151-742, Republic of Korea; Mammalian NutriPhysioGenomics, Department of Animal Sciences, and Division of Nutritional Sciences, University of Illinois, 1207 West Gregory Drive, Urbana 61801
| | - J S Osorio
- Mammalian NutriPhysioGenomics, Department of Animal Sciences, and Division of Nutritional Sciences, University of Illinois, 1207 West Gregory Drive, Urbana 61801
| | - E Schmitt
- Empresa Brasileira de Pesquisa Agropecuária (Embrapa), Rondônia, BR 364, Km 5.5, Zona Rural, Caixa Postal 127, CEP 76815-800, Porto Velho, Rondônia, Brazil
| | - M N Corrêa
- Universidade Federal de Pelotas, NUPEEC, Departamento Clínicas Veterinária, Campus Universitário, 96010-900, Pelotas, Rio Grande do Sul, Brazil
| | - G Bertoni
- Istituto di Zootecnica, Facoltà di Agraria, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy
| | - E Trevisi
- Istituto di Zootecnica, Facoltà di Agraria, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy
| | - J J Loor
- Mammalian NutriPhysioGenomics, Department of Animal Sciences, and Division of Nutritional Sciences, University of Illinois, 1207 West Gregory Drive, Urbana 61801.
| |
Collapse
|
30
|
Abstract
Intracellular free Ca(2+) ([Ca(2+)]i) is a highly versatile second messenger that regulates a wide range of functions in every type of cell and tissue. To achieve this versatility, the Ca(2+) signaling system operates in a variety of ways to regulate cellular processes that function over a wide dynamic range. This is particularly well exemplified for Ca(2+) signals in the liver, which modulate diverse and specialized functions such as bile secretion, glucose metabolism, cell proliferation, and apoptosis. These Ca(2+) signals are organized to control distinct cellular processes through tight spatial and temporal coordination of [Ca(2+)]i signals, both within and between cells. This article will review the machinery responsible for the formation of Ca(2+) signals in the liver, the types of subcellular, cellular, and intercellular signals that occur, the physiological role of Ca(2+) signaling in the liver, and the role of Ca(2+) signaling in liver disease.
Collapse
Affiliation(s)
- Maria Jimena Amaya
- Section of Digestive Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | | |
Collapse
|
31
|
Tabibian JH, Masyuk AI, Masyuk TV, O'Hara SP, LaRusso NF. Physiology of cholangiocytes. Compr Physiol 2013; 3:541-65. [PMID: 23720296 DOI: 10.1002/cphy.c120019] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cholangiocytes are epithelial cells that line the intra- and extrahepatic ducts of the biliary tree. The main physiologic function of cholangiocytes is modification of hepatocyte-derived bile, an intricate process regulated by hormones, peptides, nucleotides, neurotransmitters, and other molecules through intracellular signaling pathways and cascades. The mechanisms and regulation of bile modification are reviewed herein.
Collapse
|
32
|
Abstract
Primary sclerosing cholangitis is the classic hepatobiliary manifestation of inflammatory bowel disease and is generally chronic and progressive. Patients frequently present with asymptomatic, anicteric cholestasis, but many develop progressive biliary strictures with time, leading to recurrent cholangitis, biliary cirrhosis, and end-stage liver disease. Medical treatment does not slow the progression of disease, and many patients need liver transplantation, after which recurrent disease is a risk. The increased incidence of hepatobiliary cancer, which is not related to the underlying severity of biliary fibrosis, is of particular concern. Risk of colorectal cancer is also increased in patients with coexistent inflammatory bowel disease. Mechanistic insights have arisen from studies of secondary sclerosing cholangitis, in which a similar clinical profile is associated with a specific cause, and genomic studies have elucidated potential disease-initiating pathways in the primary form. The close association between inflammatory bowel disease and primary sclerosing cholangitis underscores the need to further understand the role of environmental factors in generation of lymphocytes that are postulated to be retargeted, deleteriously, to the biliary tree. Treatment of primary sclerosing cholangitis is confined to supportive measures, but advances in pathobiology suggest that new stratified approaches will soon be available.
Collapse
Affiliation(s)
- Gideon M Hirschfield
- Centre for Liver Research, National Institute for Health Research Biomedical Research Unit, University of Birmingham, Birmingham, UK.
| | | | | | | |
Collapse
|
33
|
Han Y, Glaser S, Meng F, Francis H, Marzioni M, McDaniel K, Alvaro D, Venter J, Carpino G, Onori P, Gaudio E, Alpini G, Franchitto A. Recent advances in the morphological and functional heterogeneity of the biliary epithelium. Exp Biol Med (Maywood) 2013; 238:549-65. [PMID: 23856906 DOI: 10.1177/1535370213489926] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This review focuses on the recent advances related to the heterogeneity of different-sized bile ducts with regard to the morphological and phenotypical characteristics, and the differential secretory, apoptotic and proliferative responses of small and large cholangiocytes to gastrointestinal hormones/peptides, neuropeptides and toxins. We describe several in vivo and in vitro models used for evaluating biliary heterogeneity. Subsequently, we discuss the heterogeneous proliferative and apoptotic responses of small and large cholangiocytes to liver injury and the mechanisms regulating the differentiation of small into large (more differentiated) cholangiocytes. Following a discussion on the heterogeneity of stem/progenitor cells in the biliary epithelium, we outline the heterogeneity of bile ducts in human cholangiopathies. After a summary section, we discuss the future perspectives that will further advance the field of the functional heterogeneity of the biliary epithelium.
Collapse
Affiliation(s)
- Yuyan Han
- Department of Medicine, Division Gastroenterology, Texas A&M Health Science Center, College of Medicine, TX, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Abstract
PURPOSE OF REVIEW To critically review most recent experimental evidence for the protective action of biliary HCO(3)(-) secretion against bile acid-induced bile duct damage and development of fibrosing cholangiopathy in humans and experimental animals. RECENT FINDINGS Studies in human cholangiocytes in vitro indicate that a biliary HCO(3)(-) umbrella protects against bile acid-induced cholangiocyte damage and apoptosis in humans. The Cl(-)/HCO(3)(-) exchanger, AE2, and an intact biliary glycocalyx appear crucial for its stability. Related studies with experimental animal models in vivo have to be interpreted with caution as humans and mice differ not only with regard to bile salt pool, but also their expression patterns of transport proteins and signalling molecules. SUMMARY Adequate biliary HCO(3)(-) secretion may protect against bile salt-induced cholangiopathies. Future therapeutic strategies in biliary diseases will aim at stabilizing the biliary HCO(3)(-) umbrella.
Collapse
|
35
|
Fausther M, Gonzales E, Dranoff JA. Role of purinergic P2X receptors in the control of liver homeostasis. ACTA ACUST UNITED AC 2012; 1:341-348. [PMID: 22662313 DOI: 10.1002/wmts.32] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It is now accepted that extracellular ATP and other nucleotides are potent signaling molecules, akin to neurotransmitters, hormones and lipid mediators. In the liver, several clues support a significant role for extracellular ATP-induced signaling pathways in the control of tissue homeostasis. First, ATP and other nucleotides are physiologically detected in extracellular fluids within the liver, including sinusoidal blood and intraductular bile, in various mammalian species including human and rodents. Moreover, finely tuned mechanisms of ATP release by different liver cell types have been described, under physiological cellular changes. In addition, most hepatic cells constitutively express, at the membrane level, several ATP-metabolizing ectoenzymes and ATP-sensitive receptors that modulate and transduce these mediator signals respectively. Finally, hepatic cells also express numerous membrane transporters that actively contribute to purinergic salvage pathways. Once released in the extracellular medium, unmetabolised ATP molecules can bind to purinergic P2X and P2Y receptors, and subsequently trigger various intracellular signal transduction pathways collectively referred to as purinergic signaling. In the liver, purinergic signaling has been shown to regulate key basic cellular functions, such as glucose/lipid metabolism, protein synthesis and ionic secretion, and homeostatic processes, such as cell cycle, inflammatory response and immunity. Whilst the functional relevance of P2Y receptors in liver physiology has been well documented, limited information is available regarding the potential role of hepatic P2X receptors in the modulation of liver homeostasis.
Collapse
Affiliation(s)
- Michel Fausther
- Division of Gastroenterology & Hepatology, Department, of Internal Medicine, College of Medicine, University of Arkansas for, Medical Sciences, Little Rock, AR, USA
| | | | | |
Collapse
|
36
|
Holtzclaw JD, Cornelius RJ, Hatcher LI, Sansom SC. Coupled ATP and potassium efflux from intercalated cells. Am J Physiol Renal Physiol 2011; 300:F1319-26. [PMID: 21454249 PMCID: PMC3119139 DOI: 10.1152/ajprenal.00112.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 03/24/2011] [Indexed: 12/27/2022] Open
Abstract
Increased flow in the distal nephron induces K secretion through the large-conductance, calcium-activated K channel (BK), which is primarily expressed in intercalated cells (IC). Since flow also increases ATP release from IC, we hypothesized that purinergic signaling has a role in shear stress (τ; 10 dynes/cm(2)) -induced, BK-dependent, K efflux. We found that 10 μM ATP led to increased IC Ca concentration, which was significantly reduced in the presence of the P(2) receptor blocker suramin or calcium-free buffer. ATP also produced BK-dependent K efflux, and IC volume decrease. Suramin inhibited τ-induced K efflux, suggesting that K efflux is at least partially dependent on purinergic signaling. BK-β4 small interfering (si) RNA, but not nontarget siRNA, decreased ATP secretion and both ATP-dependent and τ-induced K efflux. Similarly, carbenoxolone (25 μM), which blocks connexins, putative ATP pathways, blocked τ-induced K efflux and ATP secretion. Compared with BK-β4(-/-) mice, wild-type mice with high distal flows exhibited significantly more urinary ATP excretion. These data demonstrate coupled electrochemical efflux between K and ATP as part of the mechanism for τ-induced ATP release in IC.
Collapse
Affiliation(s)
- J David Holtzclaw
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5850, USA
| | | | | | | |
Collapse
|
37
|
Sathe MN, Woo K, Kresge C, Bugde A, Luby-Phelps K, Lewis MA, Feranchak AP. Regulation of purinergic signaling in biliary epithelial cells by exocytosis of SLC17A9-dependent ATP-enriched vesicles. J Biol Chem 2011; 286:25363-76. [PMID: 21613220 DOI: 10.1074/jbc.m111.232868] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
ATP in bile is a potent secretogogue, stimulating biliary epithelial cell (BEC) secretion through binding apical purinergic receptors. In response to mechanosensitive stimuli, BECs release ATP into bile, although the cellular basis of ATP release is unknown. The aims of this study in human and mouse BECs were to determine whether ATP release occurs via exocytosis of ATP-enriched vesicles and to elucidate the potential role of the vesicular nucleotide transporter SLC17A9 in purinergic signaling. Dynamic, multiscale, live cell imaging (confocal and total internal reflection fluorescence microscopy and a luminescence detection system with a high sensitivity charge-coupled device camera) was utilized to detect vesicular ATP release from cell populations, single cells, and the submembrane space of a single cell. In response to increases in cell volume, BECs release ATP, which was dependent on intact microtubules and vesicular trafficking pathways. ATP release occurred as stochastic point source bursts of luminescence consistent with exocytic events. Parallel studies identified ATP-enriched vesicles ranging in size from 0.4 to 1 μm that underwent fusion and release in response to increases in cell volume in a protein kinase C-dependent manner. Present in all models, SLC17A9 contributed to ATP vesicle formation and regulated ATP release. The findings are consistent with the existence of an SLC17A9-dependent ATP-enriched vesicular pool in biliary epithelium that undergoes regulated exocytosis to initiate purinergic signaling.
Collapse
Affiliation(s)
- Meghana N Sathe
- Departments of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | | | | | | | | | | | | |
Collapse
|