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Barko PC, Rubin SI, Swanson KS, McMichael MA, Ridgway MD, Williams DA. Untargeted Analysis of Serum Metabolomes in Dogs with Exocrine Pancreatic Insufficiency. Animals (Basel) 2023; 13:2313. [PMID: 37508091 PMCID: PMC10376357 DOI: 10.3390/ani13142313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/30/2023] Open
Abstract
Exocrine pancreatic insufficiency (EPI) is a malabsorptive syndrome resulting from insufficient secretion of pancreatic digestive enzymes. EPI is treated with pancreatic enzyme replacement therapy (PERT), but the persistence of clinical signs, especially diarrhea, is common after treatment. We used untargeted metabolomics of serum to identify metabolic disturbances associated with EPI and generate novel hypotheses related to its pathophysiology. Fasted serum samples were collected from dogs with EPI (n = 20) and healthy controls (n = 10), all receiving PERT. Serum metabolomes were generated using UPLC-MS/MS, and differences in relative metabolite abundances were compared between the groups. Of the 759 serum metabolites detected, 114 varied significantly (p < 0.05, q < 0.2) between dogs with EPI and healthy controls. Differences in amino acids (arginate, homoarginine, 2-oxoarginine, N-acetyl-cadaverine, and α-ketoglutaramate) and lipids (free fatty acids and docosahexaenoylcarnitine) were consistent with increased proteolysis and lipolysis, indicating a persistent catabolic state in dogs with EPI. Relative abundances of gut microbial metabolites (phenyllactate, 4-hydroxyphenylacetate, phenylacetyl-amino acids, catechol sulfates, and o-cresol-sulfate) were altered in dogs with EPI, consistent with disruptions in gut microbial communities. Increased kynurenine is consistent with the presence of intestinal inflammation in dogs with EPI. Whether these metabolic disturbances participate in the pathophysiology of EPI or contribute to the persistence of clinical signs after treatment is unknown, but they are targets for future investigations.
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Affiliation(s)
- Patrick C Barko
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | | | - Kelly S Swanson
- Department of Animal Sciences and Division of Nutritional Sciences, College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | | | - Marcella D Ridgway
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
| | - David A Williams
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61802, USA
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2
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Synergistic effects of agonists and two-pore-domain potassium channels on secretory responses of human pancreatic duct cells Capan-1. Pflugers Arch 2023; 475:361-379. [PMID: 36534232 PMCID: PMC9908661 DOI: 10.1007/s00424-022-02782-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022]
Abstract
Mechanisms of synergistic agonist stimulation and modulation of the electrochemical driving force for anion secretion are still not fully explored in human pancreatic duct epithelial cells. The first objective of this study was therefore to test whether combined agonist stimulation augments anion transport responses in the Capan-1 monolayer model of human pancreatic duct epithelium. The second objective was to test the influence of H+,K+-ATPase inhibition on anion transport in Capan-1 monolayers. The third objective was to analyze the expression and function of K+ channels in Capan-1, which could support anion secretion and cooperate with H+,K+-ATPases in pH and potassium homeostasis. The human pancreatic adenocarcinoma cell line Capan-1 was cultured conventionally or as polarized monolayers that were analyzed by Ussing chamber electrophysiological recordings. Single-cell intracellular calcium was assayed with Fura-2. mRNA isolated from Capan-1 was analyzed by use of the nCounter assay or RT-PCR. Protein expression was assessed by immunofluorescence and western blot analyses. Combined stimulation with different physiological agonists enhanced anion transport responses compared to single agonist stimulation. The responsiveness of Capan-1 cells to histamine was also revealed in these experiments. The H+,K+-ATPase inhibitor omeprazole reduced carbachol- and riluzole-induced anion transport responses. Transcript analyses revealed abundant TASK-2, TWIK-1, TWIK-2, TASK-5, KCa3.1, and KCNQ1 mRNA expression. KCNE1 mRNA and TREK-1, TREK-2, TASK-2, and KCNQ1 protein expression were also shown. This study shows that the Capan-1 model recapitulates key physiological aspects of a bicarbonate-secreting epithelium and constitutes a valuable model for functional studies on human pancreatic duct epithelium.
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3
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Faraoni EY, Ju C, Robson SC, Eltzschig HK, Bailey-Lundberg JM. Purinergic and Adenosinergic Signaling in Pancreatobiliary Diseases. Front Physiol 2022; 13:849258. [PMID: 35360246 PMCID: PMC8964054 DOI: 10.3389/fphys.2022.849258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/03/2022] [Indexed: 12/12/2022] Open
Abstract
Adenosine 5'-triphosphate (ATP), other nucleotides, and the nucleoside analogue, adenosine, all have the capacity to modulate cellular signaling pathways. The cellular processes linked to extracellular purinergic signaling are crucial in the initiation, evolution, and resolution of inflammation. Injured or dying cells in the pancreatobiliary tract secrete or release ATP, which results in sustained purinergic signaling mediated through ATP type-2 purinergic receptors (P2R). This process can result in chronic inflammation, fibrosis, and tumor development. In contrast, signaling via the extracellular nucleoside derivative adenosine via type-1 purinergic receptors (P1R) is largely anti-inflammatory, promoting healing. Failure to resolve inflammation, as in the context of primary sclerosing cholangitis or chronic pancreatitis, is a risk factor for parenchymal and end-organ scarring with the associated risk of pancreatobiliary malignancies. Emerging immunotherapeutic strategies suggest that targeting purinergic and adenosinergic signaling can impact the growth and invasive properties of cancer cells, potentiate anti-tumor immunity, and also block angiogenesis. In this review, we dissect out implications of disordered purinergic responses in scar formation, end-organ injury, and in tumor development. We conclude by addressing promising opportunities for modulation of purinergic/adenosinergic signaling in the prevention and treatment of pancreatobiliary diseases, inclusive of cancer.
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Affiliation(s)
- Erika Y. Faraoni
- Department of Anesthesiology, Center for Perioperative Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Cynthia Ju
- Department of Anesthesiology, Center for Perioperative Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Simon C. Robson
- Departments of Internal Medicine and Anesthesiology, Center for Inflammation Research, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Holger K. Eltzschig
- Department of Anesthesiology, Center for Perioperative Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Jennifer M. Bailey-Lundberg
- Department of Anesthesiology, Center for Perioperative Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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4
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Díaz-Muñoz M, Hernández-Muñoz R, Butanda-Ochoa A. Structure-activity features of purines and their receptors: implications in cell physiopathology. MOLECULAR BIOMEDICINE 2022; 3:5. [PMID: 35079944 PMCID: PMC8789959 DOI: 10.1186/s43556-022-00068-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/19/2022] [Indexed: 11/21/2022] Open
Abstract
The purine molecular structure consists of fused pyrimidine and imidazole rings. Purines are main pieces that conform the structure of nucleic acids which rule the inheritance processes. Purines also work as metabolic intermediates in different cell functions and as messengers in the signaling pathways throughout cellular communication. Purines, mainly ATP and adenosine (ADO), perform their functional and pharmacological properties because of their structural/chemical characteristics that make them either targets of mutagenesis, mother frameworks for designing molecules with controlled effects (e.g. anti-cancer), or chemical donors (e.g., of methyl groups, which represent a potential chemoprotective action against cancer). Purines functions also come from their effect on specific receptors, channel-linked and G-protein coupled for ATP, and exclusively G-coupled receptors for ADO (also known as ADORAs), which are involved in cell signaling pathways, there, purines work as chemical messengers with autocrine, paracrine, and endocrine actions that regulate cell metabolism and immune response in tumor progression which depends on the receptor types involved in these signals. Purines also have antioxidant and anti-inflammatory properties and participate in the cell energy homeostasis. Therefore, purine physiology is important for a variety of functions relevant to cellular health; thus, when these molecules present a homeostatic imbalance, the stability and survival of the cellular systems become compromised.
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Affiliation(s)
- Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular Y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, UNAM, Boulevard Juriquilla 3001, C.P. 76230, Juriquilla, Querétaro, México
| | - Rolando Hernández-Muñoz
- Departamento de Biología Celular Y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, UNAM, Ciudad Universitaria/Circuito Exterior, C.P. 04510, Ciudad de México, México
| | - Armando Butanda-Ochoa
- Departamento de Biología Celular Y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, UNAM, Ciudad Universitaria/Circuito Exterior, C.P. 04510, Ciudad de México, México.
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5
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Li HX, Liang XY, Wu JH, Yuan YP, Gao Y, Cai SH. Simvastatin attenuates acute lung injury by activation of A2B adenosine receptor. Toxicol Appl Pharmacol 2021; 422:115460. [PMID: 33774062 DOI: 10.1016/j.taap.2021.115460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 01/13/2021] [Accepted: 02/10/2021] [Indexed: 12/31/2022]
Abstract
To explore the protective mechanism of simvastatin in acute lung injury (ALI), the lipopolysaccharide (LPS) induced (5 mg/kg) ALI rat model was used to examine the effects of simvastatin. Following simvastatin treatment, the histopathological evaluation of lung tissues was made using hematoxylin and eosin (H&E) staining. Also, myeloperoxidase (MPO) activity and the levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-10 were determined by ELISA. Blood gas analyses of arterial blood samples were performed to assess the pulmonary gas exchange. Moreover, the neutrophil count and total protein content were determined in the bronchoalveolar lavage (BAL) fluid. The ratio of wet lung to dry lung (W/D) and the alveolar fluid clearance (AFC) were calculated to estimate the severity of edema. Lastly, the levels of A2BAR, CFTR, claudin4, and claudin18 were also measured by qRT-PCR and Western blotting. Simvastatin treatment, in a dose-related manner, markedly improved the lung histological injury and decreased the levels of TNF-α, IL-1β, and increased IL-10 in LPS induced ALI. Also, pulmonary neutrophil count was alleviated. Besides, a decreased ratio of W/D lung also confirmed the simvastatin intervention. Notably, simvastatin reduced the levels of A2BAR, CFTR, and claudin18 but upregulated claudin4 in lung tissues. Additionally, treatment with PSB1115, an antagonist of A2BAR, countered the protective effect of simvastatin in ALI. Our study demonstrates that simvastatin has a protective effect against LPS-induced ALI by activating A2BAR and should be exploited as a novel therapeutic target for the treatment of ALI.
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Affiliation(s)
- Hong-Xia Li
- Department of Respiratory and Critical Care Medicine, The Second Medical Center, National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing 100853, China
| | - Xiao-Yan Liang
- Department of Respiratory Medicine in Special Wards, Chinese PLA General Hospital, Beijing 100853, China
| | - Jiong-He Wu
- Department of Respiratory and Critical Care Medicine, The Second Medical Center, National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing 100853, China
| | - Ya-Ping Yuan
- Department of Respiratory and Critical Care Medicine, The Second Medical Center, National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing 100853, China
| | - Yue Gao
- Beijing Institute of Radiation Medicine, AMMS, Haidian, Beijing 100039, China.
| | - Shao-Hua Cai
- Department of Respiratory Medicine in Special Wards, Chinese PLA General Hospital, Beijing 100853, China.
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6
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Novak I, Yu H, Magni L, Deshar G. Purinergic Signaling in Pancreas-From Physiology to Therapeutic Strategies in Pancreatic Cancer. Int J Mol Sci 2020; 21:E8781. [PMID: 33233631 PMCID: PMC7699721 DOI: 10.3390/ijms21228781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 02/06/2023] Open
Abstract
The purinergic signaling has an important role in regulating pancreatic exocrine secretion. The exocrine pancreas is also a site of one of the most serious cancer forms, the pancreatic ductal adenocarcinoma (PDAC). Here, we explore how the network of purinergic and adenosine receptors, as well as ecto-nucleotidases regulate normal pancreatic cells and various cells within the pancreatic tumor microenvironment. In particular, we focus on the P2X7 receptor, P2Y2 and P2Y12 receptors, as well as A2 receptors and ecto-nucleotidases CD39 and CD73. Recent studies indicate that targeting one or more of these candidates could present new therapeutic approaches to treat pancreatic cancer. In pancreatic cancer, as much as possible of normal pancreatic function should be preserved, and therefore physiology of purinergic signaling in pancreas needs to be considered.
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MESH Headings
- 5'-Nucleotidase/genetics
- 5'-Nucleotidase/immunology
- Animals
- Antibodies, Monoclonal/therapeutic use
- Antineoplastic Agents, Immunological/therapeutic use
- Apyrase/genetics
- Apyrase/immunology
- Carcinoma, Pancreatic Ductal/drug therapy
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/immunology
- Carcinoma, Pancreatic Ductal/pathology
- Clinical Trials as Topic
- GPI-Linked Proteins/genetics
- GPI-Linked Proteins/immunology
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/immunology
- Humans
- Immunotherapy/methods
- Pancreas/drug effects
- Pancreas/immunology
- Pancreas/pathology
- Pancreatic Neoplasms/drug therapy
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/immunology
- Pancreatic Neoplasms/pathology
- Pancreatic Stellate Cells/drug effects
- Pancreatic Stellate Cells/immunology
- Pancreatic Stellate Cells/pathology
- Receptors, Adenosine A2/genetics
- Receptors, Adenosine A2/immunology
- Receptors, Purinergic P2X7/genetics
- Receptors, Purinergic P2X7/immunology
- Receptors, Purinergic P2Y12/genetics
- Receptors, Purinergic P2Y12/immunology
- Receptors, Purinergic P2Y2/genetics
- Receptors, Purinergic P2Y2/immunology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Tumor Microenvironment/drug effects
- Tumor Microenvironment/genetics
- Tumor Microenvironment/immunology
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Affiliation(s)
- Ivana Novak
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, 2100 Copenhagen Ø, Denmark; (H.Y.); (L.M.); (G.D.)
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7
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Pharmacological polysulfide suppresses glucose-stimulated insulin secretion in an ATP-sensitive potassium channel-dependent manner. Sci Rep 2019; 9:19377. [PMID: 31852936 PMCID: PMC6920347 DOI: 10.1038/s41598-019-55848-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/03/2019] [Indexed: 12/17/2022] Open
Abstract
Hydrogen sulfide (H2S) is an endogenous gaseous transmitter synthesized in various cell types. It is well established that H2S functions in many physiological processes, including the relaxation of vascular smooth muscle, mediation of neurotransmission, regulation of inflammation, and modulation of insulin signaling. In recent years, it has been revealed that polysulfides, substances with a varying number of sulfur atoms (H2Sn), are generated endogenously from H2S in the presence of oxygen. A series of studies describes that sulfane sulfur has the unique ability to bind reversibly to other sulfur atoms to form hydropersulfides and polysulfides, and that polysulfides activate ion channels and promote calcium influx. Furthermore, polysulfides regulate tumor suppressor activity, promote the activation of transcription factors targeting antioxidant genes and regulate blood pressure by vascular smooth muscle relaxation. Insulin secretion from pancreatic β cells plays a critical role in response to increased blood glucose concentration. H2S has emerged as an important regulator of glycemic control and exhibits characteristic regulation of glucose homeostasis. However, the effects of polysulfides on glucose-stimulated insulin secretion (GSIS) are largely unknown. In this study, we demonstrated that pharmacological polysulfide salts including Na2S2, Na2S3, and Na2S4 considerably inhibit GSIS in mouse and rat pancreatic β-cell-derived MIN6 and INS-1 cell lines, and that the effect is dependent on the activation of ATP-sensitive potassium channels. In addition, we demonstrated that a mixture of Na2S and diethylamine NONOate inhibits GSIS in a similar way to the pharmacological administration of polysulfide salts.
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8
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Kusunoki M, Hayashi M, Shoji T, Uba T, Tanaka H, Sumi C, Matsuo Y, Hirota K. Propofol inhibits stromatoxin-1-sensitive voltage-dependent K + channels in pancreatic β-cells and enhances insulin secretion. PeerJ 2019; 7:e8157. [PMID: 31824770 PMCID: PMC6894434 DOI: 10.7717/peerj.8157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/04/2019] [Indexed: 12/31/2022] Open
Abstract
Background Proper glycemic control is an important goal of critical care medicine, including perioperative patient care that can influence patients’ prognosis. Insulin secretion from pancreatic β-cells is generally assumed to play a critical role in glycemic control in response to an elevated blood glucose concentration. Many animal and human studies have demonstrated that perioperative drugs, including volatile anesthetics, have an impact on glucose-stimulated insulin secretion (GSIS). However, the effects of the intravenous anesthetic propofol on glucose metabolism and insulin sensitivity are largely unknown at present. Methods The effect of propofol on insulin secretion under low glucose or high glucose was examined in mouse MIN6 cells, rat INS-1 cells, and mouse pancreatic β-cells/islets. Cellular oxygen or energy metabolism was measured by Extracellular Flux Analyzer. Expression of glucose transporter 2 (GLUT2), potassium channels, and insulin mRNA was assessed by qRT-PCR. Protein expression of voltage-dependent potassium channels (Kv2) was also assessed by immunoblot. Propofol’s effects on potassium channels including stromatoxin-1-sensitive Kv channels and cellular oxygen and energy metabolisms were also examined. Results We showed that propofol, at clinically relevant doses, facilitates insulin secretion under low glucose conditions and GSIS in MIN6, INS-1 cells, and pancreatic β-cells/islets. Propofol did not affect intracellular ATP or ADP concentrations and cellular oxygen or energy metabolism. The mRNA expression of GLUT2 and channels including the voltage-dependent calcium channels Cav1.2, Kir6.2, and SUR1 subunit of KATP, and Kv2 were not affected by glucose or propofol. Finally, we demonstrated that propofol specifically blocks Kv currents in β-cells, resulting in insulin secretion in the presence of glucose. Conclusions Our data support the hypothesis that glucose induces membrane depolarization at the distal site, leading to KATP channel closure, and that the closure of Kv channels by propofol depolarization in β-cells enhances Ca2+ entry, leading to insulin secretion. Because its activity is dependent on GSIS, propofol and its derivatives are potential compounds that enhance and initiate β-cell electrical activity.
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Affiliation(s)
- Munenori Kusunoki
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Mikio Hayashi
- Department of Cell Physiology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Tomohiro Shoji
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Takeo Uba
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Hiromasa Tanaka
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Chisato Sumi
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Yoshiyuki Matsuo
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Kiichi Hirota
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
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9
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Expression of Adenosine Receptors in Rodent Pancreas. Int J Mol Sci 2019; 20:ijms20215329. [PMID: 31717704 PMCID: PMC6862154 DOI: 10.3390/ijms20215329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/18/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023] Open
Abstract
Adenosine regulates exocrine and endocrine secretions in the pancreas. Adenosine is considered to play a role in acini-to-duct signaling in the exocrine pancreas. To identify the molecular basis of functional adenosine receptors in the exocrine pancreas, immunohistochemical analysis was performed in the rat, mouse, and guinea pig pancreas, and the secretory rate and concentration of HCO3− in pancreatic juice from the rat pancreas were measured. The A2A adenosine receptor colocalized with ezrin, an A-kinase anchoring protein, in the luminal membrane of duct cells in the mouse and guinea pig pancreas. However, a strong signal ascribed to A2B adenosine receptors was detected in insulin-positive β cells in islets of Langerhans. The A2A adenosine receptor agonist 4-[2-[[6-Amino-9-(N-ethyl-β-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid (CGS 21680) stimulated HCO3−-rich fluid secretion from the rat pancreas. These results indicate that A2A adenosine receptors may be, at least in part, involved in the exocrine secretion of pancreatic duct cells via acini-to-duct signaling. The adenosine receptors may be a potential therapeutic target for cancer as well as exocrine dysfunctions of the pancreas.
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10
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Inagaki A, Hayashi M, Andharia N, Matsuda H. Involvement of butyrate in electrogenic K + secretion in rat rectal colon. Pflugers Arch 2018; 471:313-327. [PMID: 30250967 PMCID: PMC6334752 DOI: 10.1007/s00424-018-2208-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 08/22/2018] [Accepted: 09/13/2018] [Indexed: 12/27/2022]
Abstract
Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, are synthesized from dietary carbohydrates by colonic bacterial fermentation. These SCFAs supply energy, suppress cancer, and affect ion transport. However, their roles in ion transport and regulation in the intracellular environment remain unknown. In order to elucidate the roles of SCFAs, we measured short-circuit currents (ISC) and performed RT-PCR and immunohistochemical analyses of ion transporters in rat rectal colon. The application of 30 mM butyrate shifted ISC in a negative direction, but did not attenuate the activity of epithelial Na+ channels (ENaC). The application of bumetanide, a Na+-K+-2Cl− cotransporter inhibitor, to the basolateral side reduced the negative ISC shift induced by butyrate. The application of XE991, a KCNQ-type K+ channel inhibitor, to the apical side decreased the ISC shift induced by butyrate in a dose-dependent manner. The ISC shift was independent of HCO3− and insensitive to ibuprofen, an SMCT1 inhibitor. The mucosa from rat rectal colon expressed mRNAs of H+-coupled monocarboxylate transporters (MCT1, MCT4, and MCT5, also referred to as SLC16A1, SLC16A3, and SLC16A4, respectively). RT-PCR and immunofluorescence analyses demonstrated that KCNQ2 and KCNQ4 localized to the apical membrane of surface cells in rat rectal colon. These results indicate that butyrate, which may be transported by H+-coupled monocarboxylate transporters, activates K+ secretion through KCNQ-type K+ channels on the apical membrane in rat rectal colon. KCNQ-type K+ channels may play a role in intestinal secretion and defense mechanisms in the gastrointestinal tract.
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Affiliation(s)
- Akihiro Inagaki
- Medical Research Project, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan.
| | - Mikio Hayashi
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
| | - Naaz Andharia
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
| | - Hiroko Matsuda
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
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11
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Jung D, Alshaikh A, Ratakonda S, Bashir M, Amin R, Jeon S, Stevens J, Sharma S, Ahmed W, Musch M, Hassan H. Adenosinergic signaling inhibits oxalate transport by human intestinal Caco2-BBE cells through the A 2B adenosine receptor. Am J Physiol Cell Physiol 2018; 315:C687-C698. [PMID: 30020825 DOI: 10.1152/ajpcell.00024.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most kidney stones (KS) are composed of calcium oxalate, and small increases in urine oxalate affect the stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 (PAT1) plays a crucial role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and related KS, reflecting the importance of understanding regulation of intestinal oxalate transport. We previously showed that ATP and UTP inhibit oxalate transport by human intestinal Caco2-BBE cells (C2). Since ATP is rapidly degraded to adenosine (ADO), we examined whether intestinal oxalate transport is regulated by ADO. We measured [14C]oxalate uptake in the presence of an outward Cl gradient as an assay of Cl-oxalate exchange activity, ≥49% of which is PAT1-mediated in C2 cells. We found that ADO significantly inhibited oxalate transport by C2 cells, an effect completely blocked by the nonselective ADO receptor antagonist 8- p-sulfophenyltheophylline. ADO also significantly inhibited oxalate efflux by C2 cells, which is important since PAT1 mediates oxalate efflux in vivo. Using pharmacological antagonists and A2B adenosine receptor (A2B AR) siRNA knockdown studies, we observed that ADO inhibits oxalate transport through the A2B AR, phospholipase C, and PKC. ADO inhibits oxalate transport by reducing PAT1 surface expression as shown by biotinylation studies. We conclude that ADO inhibits oxalate transport by lowering PAT1 surface expression in C2 cells through signaling pathways including the A2B AR, PKC, and phospholipase C. Given higher ADO levels and overexpression of the A2B AR in inflammatory bowel disease (IBD), our findings have potential relevance to pathophysiology of IBD-associated hyperoxaluria and related KS.
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Affiliation(s)
- Daniel Jung
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Altayeb Alshaikh
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | | | - Mohamed Bashir
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Ruhul Amin
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sohee Jeon
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Jan Stevens
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Sapna Sharma
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Wahaj Ahmed
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Mark Musch
- Department of Medicine, The University of Chicago , Chicago, Illinois
| | - Hatim Hassan
- Department of Medicine, The University of Chicago , Chicago, Illinois
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Andharia N, Hayashi M, Matsuda H. Electrophysiological properties of anion exchangers in the luminal membrane of guinea pig pancreatic duct cells. Pflugers Arch 2018; 470:897-907. [PMID: 29399744 PMCID: PMC5945753 DOI: 10.1007/s00424-018-2116-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/10/2018] [Accepted: 01/23/2018] [Indexed: 12/12/2022]
Abstract
The pancreatic duct epithelium secretes the HCO3−-rich pancreatic juice. The HCO3− transport across the luminal membrane has been proposed to be mediated by SLC26A Cl−–HCO3− exchangers. To examine the electrophysiological properties of Cl−–HCO3− exchangers, we directly measured HCO3− conductance in the luminal membrane of the interlobular pancreatic duct cells from guinea pigs using an inside-out patch-clamp technique. Intracellular HCO3− increased the HCO3− conductance with a half-maximal effective concentration value of approximately 30 mM. The selectivity sequence based on permeability ratios was SCN− (1.4) > Cl− (1.2) = gluconate (1.1) = I− (1.1) = HCO3− (1.0) > methanesulfonate (0.6). The sequence of the relative conductance was HCO3− (1.0) > SCN− (0.7) = I− (0.7) > Cl− (0.5) = gluconate (0.4) > methanesulfonate (0.2). The current dependent on intracellular HCO3− was reduced by replacement of extracellular Cl− with gluconate or by H2DIDS, an inhibitor of Cl−–HCO3− exchangers. RT-PCR analysis revealed that the interlobular and main ducts expressed all SLC26A family members except Slc26a5 and Slc26a8. SLC26A1, SLC26A4, SLC26A6, and SLC26A10 were found to be localized to the luminal membrane of the guinea pig pancreatic duct by immunohistochemistry. These results demonstrate that these SLC26A Cl−–HCO3− exchangers may mediate the electrogenic HCO3− transport through the luminal membrane and may be involved in pancreatic secretion in guinea pig ducts.
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Affiliation(s)
- N Andharia
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
| | - M Hayashi
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan.
| | - H Matsuda
- Department of Physiology, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, 573-1010, Japan
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