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Ouassou H, Elhouda Daoudi N, Bouknana S, Abdnim R, Bnouham M. A Review of Antidiabetic Medicinal Plants as a Novel Source of Phosphodiesterase Inhibitors: Future Perspective of New Challenges Against Diabetes Mellitus. Med Chem 2024; 20:467-486. [PMID: 38265379 DOI: 10.2174/0115734064255060231116192839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/31/2023] [Accepted: 09/25/2023] [Indexed: 01/25/2024]
Abstract
Intracellular glucose concentration plays a crucial role in initiating the molecular secretory process of pancreatic β-cells through multiple messengers and signaling pathways. Cyclic nucleotides are key physiological regulators that modulate pathway interactions in β -cells. An increase of cyclic nucleotides is controled by hydrolysed phosphodiesterases (PDEs), which degrades cyclic nucleotides into inactive metabolites. Despite the undeniable therapeutic potential of PDE inhibitors, they are associated with several side effects. The treatment strategy for diabetes based on PDE inhibitors has been proposed for a long time. Hence, the world of natural antidiabetic medicinal plants represents an ideal source of phosphodiesterase inhibitors as a new strategy for developing novel agents to treat diabetes mellitus. This review highlights medicinal plants traditionally used in the treatment of diabetes mellitus that have been proven to have inhibitory effects on PDE activity. The contents of this review were sourced from electronic databases, including Science Direct, PubMed, Springer Link, Web of Science, Scopus, Wiley Online, Scifinder and Google Scholar. These databases were consulted to collect information without any limitation date. After comprehensive literature screening, this paper identified 27 medicinal plants that have been reported to exhibit anti-phosphodiesterase activities. The selection of these plants was based on their traditional uses in the treatment of diabetes mellitus. The review emphasizes the antiphosphodiesterase properties of 31 bioactive components derived from these plant extracts. Many phenolic compounds have been identified as PDE inhibitors: Brazilin, mesozygin, artonin I, chalcomaracin, norartocarpetin, moracin L, moracin M, moracin C, curcumin, gallic acid, caffeic acid, rutin, quercitrin, quercetin, catechin, kaempferol, chlorogenic acid, and ellagic acid. Moreover, smome lignans have reported as PDE inhibitors: (+)-Medioresinol di-O-β-d-glucopyranoside, (+)- Pinoresinol di-O-β-d-glucopyranoside, (+)-Pinoresinol-4-O-β-d-glucopyranosyl (1→6)-β-dglucopyranoside, Liriodendrin, (+)-Pinoresinol 4'-O-β-d-glucopyranoside, and forsythin. This review provides a promising starting point of medicinal plants, which could be further studied for the development of natural phosphodiesterase inhibitors to treat diabetes mellitus. Therefore, it is important to consider clinical studies for the identification of new targets for the treatment of diabetes.
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Affiliation(s)
- Hayat Ouassou
- Higher Institute of Nurses Professions and Health Techniques, Oujda 60000, Morocco
- Laboratory of Bioresources, Biotechnology, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, Mohammed First University, BP. 717, Oujda 60040, Morocco
| | - Nour Elhouda Daoudi
- Laboratory of Bioresources, Biotechnology, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, Mohammed First University, BP. 717, Oujda 60040, Morocco
| | - Saliha Bouknana
- Department of Biology, Faculty of Sciences, University Mohammed First, Boulevard Mohamed VI BP 717, Oujda 60040, Morocco
| | - Rhizlan Abdnim
- Laboratory of Bioresources, Biotechnology, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, Mohammed First University, BP. 717, Oujda 60040, Morocco
| | - Mohamed Bnouham
- Laboratory of Bioresources, Biotechnology, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, Mohammed First University, BP. 717, Oujda 60040, Morocco
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Yang C, Wei M, Zhao Y, Yang Z, Song M, Mi J, Yang X, Tian G. Regulation of insulin secretion by the post-translational modifications. Front Cell Dev Biol 2023; 11:1217189. [PMID: 37601108 PMCID: PMC10436566 DOI: 10.3389/fcell.2023.1217189] [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: 05/05/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Post-translational modification (PTM) has a significant impact on cellular signaling and function regulation. In pancreatic β cells, PTMs are involved in insulin secretion, cell development, and viability. The dysregulation of PTM in β cells is clinically associated with the development of diabetes mellitus. Here, we summarized current findings on major PTMs occurring in β cells and their roles in insulin secretion. Our work provides comprehensive insight into understanding the mechanisms of insulin secretion and potential therapeutic targets for diabetes from the perspective of protein PTMs.
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Affiliation(s)
- Chunhua Yang
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Mengna Wei
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Yanpu Zhao
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Zhanyi Yang
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Mengyao Song
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Jia Mi
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Xiaoyong Yang
- Yale Center for Molecular and Systems Metabolism, Department of Comparative Medicine, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, United States
| | - Geng Tian
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
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Lugnier C. The Complexity and Multiplicity of the Specific cAMP Phosphodiesterase Family: PDE4, Open New Adapted Therapeutic Approaches. Int J Mol Sci 2022; 23:ijms231810616. [PMID: 36142518 PMCID: PMC9502408 DOI: 10.3390/ijms231810616] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/04/2022] [Accepted: 09/07/2022] [Indexed: 11/19/2022] Open
Abstract
Cyclic nucleotides (cAMP, cGMP) play a major role in normal and pathologic signaling. Beyond receptors, cyclic nucleotide phosphodiesterases; (PDEs) rapidly convert the cyclic nucleotide in its respective 5′-nucleotide to control intracellular cAMP and/or cGMP levels to maintain a normal physiological state. However, in many pathologies, dysregulations of various PDEs (PDE1-PDE11) contribute mainly to organs and tissue failures related to uncontrolled phosphorylation cascade. Among these, PDE4 represents the greatest family, since it is constituted by 4 genes with multiple variants differently distributed at tissue, cellular and subcellular levels, allowing different fine-tuned regulations. Since the 1980s, pharmaceutical companies have developed PDE4 inhibitors (PDE4-I) to overcome cardiovascular diseases. Since, they have encountered many undesired problems, (emesis), they focused their research on other PDEs. Today, increases in the knowledge of complex PDE4 regulations in various tissues and pathologies, and the evolution in drug design, resulted in a renewal of PDE4-I development. The present review describes the recent PDE4-I development targeting cardiovascular diseases, obesity, diabetes, ulcerative colitis, and Crohn’s disease, malignancies, fatty liver disease, osteoporosis, depression, as well as COVID-19. Today, the direct therapeutic approach of PDE4 is extended by developing allosteric inhibitors and protein/protein interactions allowing to act on the PDE interactome.
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Affiliation(s)
- Claire Lugnier
- Section de Structures Biologiques, Pharmacologie et Enzymologie, CNRS/Unistra, CRBS, UR 3072, CEDEX, 67084 Strasbourg, France
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Jankowska A, Pawłowski M, Chłoń-Rzepa G. Diabetic Theory in Anti-Alzheimer's Drug Research and Development. Part 2: Therapeutic Potential of cAMP-Specific Phosphodiesterase Inhibitors. Curr Med Chem 2021; 28:3535-3553. [PMID: 32940168 DOI: 10.2174/0929867327666200917125857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/21/2020] [Accepted: 08/25/2020] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is one of the most prevalent age-related neurodegenerative disease that affects the cognition, behavior, and daily activities of individuals. Studies indicate that this disease is characterized by several pathological mechanisms, including the accumulation of amyloid-beta peptide, hyperphosphorylation of tau protein, impairment of cholinergic neurotransmission, and increase in inflammatory responses within the central nervous system. Chronic neuroinflammation associated with AD is closely related to disturbances in metabolic processes, including insulin release and glucose metabolism. As AD is also called type III diabetes, diverse compounds having antidiabetic effects have been investigated as potential drugs for its symptomatic and disease-modifying treatment. In addition to insulin and oral antidiabetic drugs, scientific attention has been paid to cyclic-3',5'-adenosine monophosphate (cAMP)-specific phosphodiesterase (PDE) inhibitors that can modulate the concentration of glucose and related hormones and exert beneficial effects on memory, mood, and emotional processing. In this review, we present the most recent reports focusing on the involvement of cAMP-specific PDE4, PDE7, and PDE8 in glycemic and inflammatory response controls as well as the potential utility of the PDE inhibitors in the treatment of AD. Besides the results of in vitro and in vivo studies, the review also presents recent reports from clinical trials.
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Affiliation(s)
- Agnieszka Jankowska
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Medicinal Chemistry, 9 Medyczna Street, Krakow 30-688, Poland
| | - Maciej Pawłowski
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Medicinal Chemistry, 9 Medyczna Street, Krakow 30-688, Poland
| | - Grażyna Chłoń-Rzepa
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Medicinal Chemistry, 9 Medyczna Street, Krakow 30-688, Poland
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Shuai H, Xu Y, Ahooghalandari P, Tengholm A. Glucose-induced cAMP elevation in β-cells involves amplification of constitutive and glucagon-activated GLP-1 receptor signalling. Acta Physiol (Oxf) 2021; 231:e13611. [PMID: 33369112 PMCID: PMC8047901 DOI: 10.1111/apha.13611] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 12/17/2020] [Accepted: 12/19/2020] [Indexed: 01/02/2023]
Abstract
Aim cAMP typically signals downstream of Gs‐coupled receptors and regulates numerous cell functions. In β‐cells, cAMP amplifies Ca2+‐triggered exocytosis of insulin granules. Glucose‐induced insulin secretion is associated with Ca2+‐ and metabolism‐dependent increases of the sub‐plasma‐membrane cAMP concentration ([cAMP]pm) in β‐cells, but potential links to canonical receptor signalling are unclear. The aim of this study was to clarify the role of glucagon‐like peptide‐1 receptors (GLP1Rs) for glucose‐induced cAMP signalling in β‐cells. Methods Total internal reflection microscopy and fluorescent reporters were used to monitor changes in cAMP, Ca2+ and ATP concentrations as well as insulin secretion in MIN6 cells and mouse and human β‐cells. Insulin release from mouse and human islets was also measured with ELISA. Results The GLP1R antagonist exendin‐(9‐39) (ex‐9) prevented both GLP1‐ and glucagon‐induced elevations of [cAMP]pm, consistent with GLP1Rs being involved in the action of glucagon. This conclusion was supported by lack of unspecific effects of the antagonist in a reporter cell‐line. Ex‐9 also suppressed IBMX‐ and glucose‐induced [cAMP]pm elevations. Depolarization with K+ triggered Ca2+‐dependent [cAMP]pm elevation, an effect that was amplified by high glucose. Ex‐9 inhibited both the Ca2+ and glucose‐metabolism‐dependent actions on [cAMP]pm. The drug remained effective after minimizing paracrine signalling by dispersing the islets and it reduced basal [cAMP]pm in a cell‐line heterologously expressing GLP1Rs, indicating that there is constitutive GLP1R signalling. The ex‐9‐induced reduction of [cAMP]pm in glucose‐stimulated β‐cells was paralleled by suppression of insulin secretion. Conclusion Agonist‐independent and glucagon‐stimulated GLP1R signalling in β‐cells contributes to basal and glucose‐induced cAMP production and insulin secretion.
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Affiliation(s)
- Hongyan Shuai
- School of Basic Medicine Sciences Dali University Yunnan China
- Department of Medical Cell Biology Biomedical Centre Uppsala University Uppsala Sweden
| | - Yunjian Xu
- Department of Medical Cell Biology Biomedical Centre Uppsala University Uppsala Sweden
| | - Parvin Ahooghalandari
- Department of Medical Cell Biology Biomedical Centre Uppsala University Uppsala Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology Biomedical Centre Uppsala University Uppsala Sweden
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Kilanowska A, Ziółkowska A. Role of Phosphodiesterase in the Biology and Pathology of Diabetes. Int J Mol Sci 2020; 21:E8244. [PMID: 33153226 PMCID: PMC7662747 DOI: 10.3390/ijms21218244] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
Glucose metabolism is the initiator of a large number of molecular secretory processes in β cells. Cyclic nucleotides as a second messenger are the main physiological regulators of these processes and are functionally divided into compartments in pancreatic cells. Their intracellular concentration is limited by hydrolysis led by one or more phosphodiesterase (PDE) isoenzymes. Literature data confirmed multiple expressions of PDEs subtypes, but the specific roles of each in pancreatic β-cell function, particularly in humans, are still unclear. Isoforms present in the pancreas are also found in various tissues of the body. Normoglycemia and its strict control are supported by the appropriate release of insulin from the pancreas and the action of insulin in peripheral tissues, including processes related to homeostasis, the regulation of which is based on the PDE- cyclic AMP (cAMP) signaling pathway. The challenge in developing a therapeutic solution based on GSIS (glucose-stimulated insulin secretion) enhancers targeted at PDEs is the selective inhibition of their activity only within β cells. Undeniably, PDEs inhibitors have therapeutic potential, but some of them are burdened with certain adverse effects. Therefore, the chance to use knowledge in this field for diabetes treatment has been postulated for a long time.
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Affiliation(s)
| | - Agnieszka Ziółkowska
- Department of Anatomy and Histology, Collegium Medicum, University of Zielona Gora, Zyty 28, 65-046 Zielona Gora, Poland;
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Naim N, Reece JM, Zhang X, Altschuler DL. Dual Activation of cAMP Production Through Photostimulation or Chemical Stimulation. Methods Mol Biol 2020; 2173:201-216. [PMID: 32651920 PMCID: PMC7968876 DOI: 10.1007/978-1-0716-0755-8_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
cAMP is a crucial mediator of multiple cell signaling pathways. This cyclic nucleotide requires strict spatiotemporal control for effective function. Light-activated proteins have become a powerful tool to study signaling kinetics due to having quick on/off rates and minimal off-target effects. The photoactivated adenylyl cyclase from Beggiatoa (bPAC) produces cAMP rapidly upon stimulation with blue light. However, light delivery is not always feasible, especially in vivo. Hence, we created a luminescence-activated cyclase by fusing bPAC with nanoluciferase (nLuc) to allow chemical activation of cAMP activity. This dual-activated adenylyl cyclase can be stimulated using short bursts of light or long-term chemical activation with furimazine and other related luciferins. Together these can be used to mimic transient, chronic, and oscillating patterns of cAMP signaling. Moreover, when coupled to compartment-specific targeting domains, these reagents provide a new powerful tool for cAMP spatiotemporal dynamic studies. Here, we describe detailed methods for working with bPAC-nLuc in mammalian cells, stimulating cAMP production with light and luciferins, and measuring total cAMP accumulation.
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Affiliation(s)
- Nyla Naim
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
- Molecular Pharmacology Training Program, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology, Addgene, Watertown, MA, USA
| | - Jeff M Reece
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
- Advanced Light Microscopy & Image Analysis Core (ALMIAC), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, MD, USA
| | - Xuefeng Zhang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Daniel L Altschuler
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA.
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Pratt EPS, Harvey KE, Salyer AE, Hockerman GH. Regulation of cAMP accumulation and activity by distinct phosphodiesterase subtypes in INS-1 cells and human pancreatic β-cells. PLoS One 2019; 14:e0215188. [PMID: 31442224 PMCID: PMC6707593 DOI: 10.1371/journal.pone.0215188] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 08/11/2019] [Indexed: 01/09/2023] Open
Abstract
Pancreatic β-cells express multiple phosphodiesterase (PDE) subtypes, but the specific roles for each in β-cell function, particularly in humans, is not clear. We evaluated the cellular role of PDE1, PDE3, and PDE4 activity in the rat insulinoma cell line INS-1 and in primary human β-cells using subtype-selective PDE inhibitors. Using a genetically encoded, FRET-based cAMP sensor, we found that the PDE1 inhibitor 8MM-IBMX, elevated cAMP levels in the absence of glucose to a greater extent than either the PDE3 inhibitor cilostamide or the PDE4 inhibitor rolipram. In 18 mM glucose, PDE1 inhibition elevated cAMP levels to a greater extent than PDE3 inhibition in INS-1 cells, while PDE4 inhibition was without effect. Inhibition of PDE1 or PDE4, but not PDE3, potentiated glucose-stimulated insulin secretion in INS-1 cells. PDE1 inhibition, but not PDE3 or PDE4 inhibition, reduced palmitate-induced caspase-3/7 activation, and enhanced CREB phosphorylation in INS-1 cells. In human β-cells, only PDE3 or PDE4 inhibition increased cAMP levels in 1.7 mM glucose, but PDE1, PDE3, or PDE4 inhibition potentiated cAMP levels in 16.7 mM glucose. Inhibition of PDE1 or PDE4 increased cAMP levels to a greater extent in 16.7 mM glucose than in 1.7 mM glucose in human β-cells. In contrast, elevation of cAMP levels by PDE3 inhibition was not different at these glucose concentrations. PDE1 inhibition also potentiated insulin secretion from human islets, suggesting that the role of PDE1 may be conserved between INS-1 cells and human pancreatic β-cells. Our results suggest that inhibition of PDE1 may be a useful strategy to potentiate glucose-stimulated insulin secretion, and to protect β-cells from the toxic effects of excess fatty acids.
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Affiliation(s)
- Evan P. S. Pratt
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States of America
- Purdue University Interdisciplinary Life Science Program, Purdue University, West Lafayette, IN, United States of America
| | - Kyle E. Harvey
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States of America
| | - Amy E. Salyer
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States of America
| | - Gregory H. Hockerman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States of America
- * E-mail:
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Yu Q, Shuai H, Ahooghalandari P, Gylfe E, Tengholm A. Glucose controls glucagon secretion by directly modulating cAMP in alpha cells. Diabetologia 2019; 62:1212-1224. [PMID: 30953108 PMCID: PMC6560012 DOI: 10.1007/s00125-019-4857-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/22/2019] [Indexed: 01/18/2023]
Abstract
AIMS/HYPOTHESIS Glucagon is critical for normal glucose homeostasis and aberrant secretion of the hormone aggravates dysregulated glucose control in diabetes. However, the mechanisms by which glucose controls glucagon secretion from pancreatic alpha cells remain elusive. The aim of this study was to investigate the role of the intracellular messenger cAMP in alpha-cell-intrinsic glucose regulation of glucagon release. METHODS Subplasmalemmal cAMP and Ca2+ concentrations were recorded in isolated and islet-located alpha cells using fluorescent reporters and total internal reflection microscopy. Glucagon secretion from mouse islets was measured using ELISA. RESULTS Glucose induced Ca2+-independent alterations of the subplasmalemmal cAMP concentration in alpha cells that correlated with changes in glucagon release. Glucose-lowering-induced stimulation of glucagon secretion thus corresponded to an elevation in cAMP that was independent of paracrine signalling from insulin or somatostatin. Imposed cAMP elevations stimulated glucagon secretion and abolished inhibition by glucose elevation, while protein kinase A inhibition mimicked glucose suppression of glucagon release. CONCLUSIONS/INTERPRETATION Glucose concentrations in the hypoglycaemic range control glucagon secretion by directly modulating the cAMP concentration in alpha cells independently of paracrine influences. These findings define a novel mechanism for glucose regulation of glucagon release that underlies recovery from hypoglycaemia and may be disturbed in diabetes.
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Affiliation(s)
- Qian Yu
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Hongyan Shuai
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Parvin Ahooghalandari
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Erik Gylfe
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, SE-751 23, Uppsala, Sweden.
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Brouwer S, Hoffmeister T, Gresch A, Schönhoff L, Düfer M. Resveratrol Influences Pancreatic Islets by Opposing Effects on Electrical Activity and Insulin Release. Mol Nutr Food Res 2019; 62. [PMID: 29341416 DOI: 10.1002/mnfr.201700902] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/19/2017] [Indexed: 01/27/2023]
Abstract
SCOPE Resveratrol is suggested to improve glycemic control by activation of sirtuin 1 (SIRT1) and has already been tested clinically. Our investigation characterizes the targets of resveratrol in pancreatic beta cells and their contribution to short- and long-term effects on insulin secretion. METHODS AND RESULTS Islets or beta cells are isolated from C57BL/6N mice. Electrophysiology is performed with microelectrode arrays and patch-clamp technique, insulin secretion and content are determined by radioimmunoassay, cAMP is measured by enzyme-linked immunosorbent assay, and cytosolic Ca2+ concentration by fluorescence methods. Resveratrol (25 μmol L-1 ) elevates [Ca2+ ]c and potentiates glucose-stimulated insulin secretion. These effects are associated with increased intracellular cAMP and are sensitive to the SIRT1 blocker Ex-527. Inhibition of EPAC1 by CE3F4 also abolishes the stimulatory effect of resveratrol. The underlying mechanism does not involve membrane depolarization as resveratrol even reduces electrical activity despite blocking KATP channels. Importantly, after prolonged exposure to resveratrol (14 days), the beneficial influence of the polyphenol on insulin release is lost. CONCLUSION Resveratrol addresses multiple targets in pancreatic islets. Potentiation of insulin secretion is mediated by SIRT1-dependent activation of cAMP/EPAC1. Considering resveratrol as therapeutic supplement for patients with type 2 diabetes mellitus, the inhibitory influence on electrical excitability attenuates positive effects.
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Affiliation(s)
- Simone Brouwer
- University of Münster, Pharmaceutical and Medicinal Chemistry, Dept. of Pharmacology, Münster, Germany
| | - Theresa Hoffmeister
- University of Münster, Pharmaceutical and Medicinal Chemistry, Dept. of Pharmacology, Münster, Germany
| | - Anne Gresch
- University of Münster, Pharmaceutical and Medicinal Chemistry, Dept. of Pharmacology, Münster, Germany
| | - Lisa Schönhoff
- University of Münster, Pharmaceutical and Medicinal Chemistry, Dept. of Pharmacology, Münster, Germany
| | - Martina Düfer
- University of Münster, Pharmaceutical and Medicinal Chemistry, Dept. of Pharmacology, Münster, Germany
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11
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Naim N, White AD, Reece JM, Wankhede M, Zhang X, Vilardaga JP, Altschuler DL. Luminescence-activated nucleotide cyclase regulates spatial and temporal cAMP synthesis. J Biol Chem 2018; 294:1095-1103. [PMID: 30559293 DOI: 10.1074/jbc.ac118.004905] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 12/12/2018] [Indexed: 12/15/2022] Open
Abstract
cAMP is a ubiquitous second messenger that regulates cellular proliferation, differentiation, attachment, migration, and several other processes. It has become increasingly evident that tight regulation of cAMP accumulation and localization confers divergent yet specific signaling to downstream pathways. Currently, few tools are available that have sufficient spatial and temporal resolution to study location-biased cAMP signaling. Here, we introduce a new fusion protein consisting of a light-activated adenylyl cyclase (bPAC) and luciferase (nLuc). This construct allows dual activation of cAMP production through temporally precise photostimulation or chronic chemical stimulation that can be fine-tuned to mimic physiological levels and duration of cAMP synthesis to trigger downstream events. By targeting this construct to different compartments, we show that cAMP produced in the cytosol and nucleus stimulates proliferation in thyroid cells. The bPAC-nLuc fusion construct adds a new reagent to the available toolkit to study cAMP-regulated processes in living cells.
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Affiliation(s)
- Nyla Naim
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261; Molecular Pharmacology Training Program, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Alex D White
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261; Molecular Pharmacology Training Program, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Jeff M Reece
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261
| | - Mamta Wankhede
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261
| | - Xuefeng Zhang
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261
| | | | - Daniel L Altschuler
- Department of Pharmacology and Chemical Biology, Pittsburgh, Pennsylvania 15261.
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12
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Tengholm A, Gylfe E. cAMP signalling in insulin and glucagon secretion. Diabetes Obes Metab 2017; 19 Suppl 1:42-53. [PMID: 28466587 DOI: 10.1111/dom.12993] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 01/24/2023]
Abstract
The "second messenger" archetype cAMP is one of the most important cellular signalling molecules with central functions including the regulation of insulin and glucagon secretion from the pancreatic β- and α-cells, respectively. cAMP is generally considered as an amplifier of insulin secretion triggered by Ca2+ elevation in the β-cells. Both messengers are also positive modulators of glucagon release from α-cells, but in this case cAMP may be the important regulator and Ca2+ have a more permissive role. The actions of cAMP are mediated by protein kinase A (PKA) and the guanine nucleotide exchange factor Epac. The present review focuses on how cAMP is regulated by nutrients, hormones and neural factors in β- and α-cells via adenylyl cyclase-catalysed generation and phosphodiesterase-mediated degradation. We will also discuss how PKA and Epac affect ion fluxes and the secretory machinery to transduce the stimulatory effects on insulin and glucagon secretion. Finally, we will briefly describe disturbances of the cAMP system associated with diabetes and how cAMP signalling can be targeted to normalize hypo- and hypersecretion of insulin and glucagon, respectively, in diabetic patients.
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Affiliation(s)
- Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Erik Gylfe
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
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Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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Sphingosine kinase 1-interacting protein is a novel regulator of glucose-stimulated insulin secretion. Sci Rep 2017; 7:779. [PMID: 28396589 PMCID: PMC5429731 DOI: 10.1038/s41598-017-00900-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/16/2017] [Indexed: 12/12/2022] Open
Abstract
Glucose-stimulated insulin secretion (GSIS) is essential in keeping blood glucose levels within normal range. GSIS is impaired in type 2 diabetes, and its recovery is crucial in treatment of the disease. We find here that sphingosine kinase 1-interacting protein (SKIP, also called Sphkap) is highly expressed in pancreatic β-cells but not in α-cells. Intraperitoneal glucose tolerance test showed that plasma glucose levels were decreased and insulin levels were increased in SKIP−/− mice compared to SKIP+/+ mice, but exendin-4-enhanced insulin secretion was masked. GSIS was amplified more in SKIP−/− but exendin-4-enhanced insulin secretion was masked compared to that in SKIP+/+ islets. The ATP and cAMP content were similarly increased in SKIP+/+ and SKIP−/− islets; depolarization-evoked, PKA and cAMP-mediated insulin secretion were not affected. Inhibition of PDE activity equally augmented GSIS in SKIP+/+ and SKIP−/− islets. These results indicate that SKIP modulates GSIS by a pathway distinct from that of cAMP-, PDE- and sphingosine kinase-dependent pathways.
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15
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Akerman I, Tu Z, Beucher A, Rolando DMY, Sauty-Colace C, Benazra M, Nakic N, Yang J, Wang H, Pasquali L, Moran I, Garcia-Hurtado J, Castro N, Gonzalez-Franco R, Stewart AF, Bonner C, Piemonti L, Berney T, Groop L, Kerr-Conte J, Pattou F, Argmann C, Schadt E, Ravassard P, Ferrer J. Human Pancreatic β Cell lncRNAs Control Cell-Specific Regulatory Networks. Cell Metab 2017; 25:400-411. [PMID: 28041957 PMCID: PMC5300904 DOI: 10.1016/j.cmet.2016.11.016] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 10/01/2016] [Accepted: 11/29/2016] [Indexed: 12/28/2022]
Abstract
Recent studies have uncovered thousands of long non-coding RNAs (lncRNAs) in human pancreatic β cells. β cell lncRNAs are often cell type specific and exhibit dynamic regulation during differentiation or upon changing glucose concentrations. Although these features hint at a role of lncRNAs in β cell gene regulation and diabetes, the function of β cell lncRNAs remains largely unknown. In this study, we investigated the function of β cell-specific lncRNAs and transcription factors using transcript knockdowns and co-expression network analysis. This revealed lncRNAs that function in concert with transcription factors to regulate β cell-specific transcriptional networks. We further demonstrate that the lncRNA PLUTO affects local 3D chromatin structure and transcription of PDX1, encoding a key β cell transcription factor, and that both PLUTO and PDX1 are downregulated in islets from donors with type 2 diabetes or impaired glucose tolerance. These results implicate lncRNAs in the regulation of β cell-specific transcription factor networks.
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Affiliation(s)
- Ildem Akerman
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom; Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomediques August Pi I Sunyer (IDIBAPS), Barcelona 08036, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain
| | - Zhidong Tu
- Department of Genetics and Genomic Science, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Anthony Beucher
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Delphine M Y Rolando
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Claire Sauty-Colace
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut du cerveau et de la moelle (ICM) - Hôpital Pitié-Salpêtrière, Boulevard de l'Hôpital, Paris 75013, France
| | - Marion Benazra
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut du cerveau et de la moelle (ICM) - Hôpital Pitié-Salpêtrière, Boulevard de l'Hôpital, Paris 75013, France
| | - Nikolina Nakic
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Jialiang Yang
- Department of Genetics and Genomic Science, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Huan Wang
- Department of Genetics and Genomic Science, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Lorenzo Pasquali
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain; Germans Trias i Pujol University Hospital and Research Institute and Josep Carreras Leukaemia Research Institute, Badalona 08916, Spain
| | - Ignasi Moran
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Javier Garcia-Hurtado
- Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomediques August Pi I Sunyer (IDIBAPS), Barcelona 08036, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain
| | - Natalia Castro
- Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomediques August Pi I Sunyer (IDIBAPS), Barcelona 08036, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain
| | - Roser Gonzalez-Franco
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Andrew F Stewart
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Caroline Bonner
- European Genomic Institute for Diabetes, INSERM UMR 1190, Lille 59800, France
| | - Lorenzo Piemonti
- Diabetes Research Institute (HSR-DRI), San Raffaele Scientific Institute, Milano 20132, Italy
| | - Thierry Berney
- Cell Isolation and Transplantation Center, University of Geneva, 1211 Geneva 4, Switzerland
| | - Leif Groop
- Department of Clinical Sciences, Lund University Diabetes Centre, Lund University, Lund 20502, Sweden
| | - Julie Kerr-Conte
- European Genomic Institute for Diabetes, INSERM UMR 1190, Lille 59800, France
| | - Francois Pattou
- European Genomic Institute for Diabetes, INSERM UMR 1190, Lille 59800, France
| | - Carmen Argmann
- Department of Genetics and Genomic Science, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Eric Schadt
- Department of Genetics and Genomic Science, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Philippe Ravassard
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut du cerveau et de la moelle (ICM) - Hôpital Pitié-Salpêtrière, Boulevard de l'Hôpital, Paris 75013, France
| | - Jorge Ferrer
- Section of Epigenomics and Disease, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom; Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomediques August Pi I Sunyer (IDIBAPS), Barcelona 08036, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain.
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16
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Halls ML, Cooper DMF. Adenylyl cyclase signalling complexes - Pharmacological challenges and opportunities. Pharmacol Ther 2017; 172:171-180. [PMID: 28132906 DOI: 10.1016/j.pharmthera.2017.01.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Signalling pathways involving the vital second messanger, cAMP, impact on most significant physiological processes. Unsurprisingly therefore, the activation and regulation of cAMP signalling is tightly controlled within the cell by processes including phosphorylation, the scaffolding of protein signalling complexes and sub-cellular compartmentalisation. This inherent complexity, along with the highly conserved structure of the catalytic sites among the nine membrane-bound adenylyl cyclases, presents significant challenges for efficient inhibition of cAMP signalling. Here, we will describe the biochemistry and cell biology of the family of membrane-bound adenylyl cyclases, their organisation within the cell, and the nature of the cAMP signals that they produce, as a prelude to considering how cAMP signalling might be perturbed. We describe the limitations associated with direct inhibition of adenylyl cyclase activity, and evaluate alternative strategies for more specific targeting of adenylyl cyclase signalling. The inherent complexity in the activation and organisation of adenylyl cyclase activity may actually provide unique opportunities for selectively targeting discrete adenylyl cyclase functions in disease.
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Affiliation(s)
- Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, Victoria, Australia
| | - Dermot M F Cooper
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK.
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17
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Zhai K, Gu L, Yang Z, Mao Y, Jin M, Chang Y, Yuan Q, Leblais V, Wang H, Fischmeister R, Ji G. RNA-binding protein CUGBP1 regulates insulin secretion via activation of phosphodiesterase 3B in mice. Diabetologia 2016; 59:1959-67. [PMID: 27255754 DOI: 10.1007/s00125-016-4005-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 05/16/2016] [Indexed: 01/17/2023]
Abstract
AIMS/HYPOTHESIS CUG-binding protein 1 (CUGBP1) is a multifunctional RNA-binding protein that regulates RNA processing at several stages including translation, deadenylation and alternative splicing, as well as RNA stability. Recent studies indicate that CUGBP1 may play a role in metabolic disorders. Our objective was to examine its role in endocrine pancreas function through gain- and loss-of-function experiments and to further decipher the underlying molecular mechanisms. METHODS A mouse model in which type 2 diabetes was induced by a high-fat diet (HFD; 60% energy from fat) and mice on a standard chow diet (10% energy from fat) were compared. Pancreas-specific CUGBP1 overexpression and knockdown mice were generated. Different lengths of the phosphodiesterase subtype 3B (PDE3B) 3' untranslated region (UTR) were cloned for luciferase reporter analysis. Purified CUGBP1 protein was used for gel shift experiments. RESULTS CUGBP1 is present in rodent islets and in beta cell lines; it is overexpressed in the islets of diabetic mice. Compared with control mice, the plasma insulin level after a glucose load was significantly lower and glucose clearance was greatly delayed in mice with pancreas-specific CUGBP1 overexpression; the opposite results were obtained upon pancreas-specific CUGBP1 knockdown. Glucose- and glucagon-like peptide1 (GLP-1)-stimulated insulin secretion was significantly attenuated in mouse islets upon CUGBP1 overexpression. This was associated with a strong decrease in intracellular cAMP levels, pointing to a potential role for cAMP PDEs. CUGBP1 overexpression had no effect on the mRNA levels of PDE1A, 1C, 2A, 3A, 4A, 4B, 4D, 7A and 8B subtypes, but resulted in increased PDE3B expression. CUGBP1 was found to directly bind to a specific ATTTGTT sequence residing in the 3' UTR of PDE3B and stabilised PDE3B mRNA. In the presence of the PDE3 inhibitor cilostamide, glucose- and GLP-1-stimulated insulin secretion was no longer reduced by CUGBP1 overexpression. Similar to CUGBP1, PDE3B was overexpressed in the islets of diabetic mice. CONCLUSIONS/INTERPRETATION We conclude that CUGBP1 is a critical regulator of insulin secretion via activating PDE3B. Repressing this protein might provide a potential strategy for treating type 2 diabetes.
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Affiliation(s)
- Kui Zhai
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Lei Gu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Zhiguang Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yang Mao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Meng Jin
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yan Chang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Qi Yuan
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Veronique Leblais
- Inserm, UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, 5 rue J.-B. Clément, 92296, Châtenay-Malabry, France
| | - Huiwen Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Rodolphe Fischmeister
- Inserm, UMR-S 1180, Faculté de Pharmacie, Université Paris-Sud, 5 rue J.-B. Clément, 92296, Châtenay-Malabry, France.
| | - Guangju Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
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18
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Kolic J, Manning Fox JE, Chepurny OG, Spigelman AF, Ferdaoussi M, Schwede F, Holz GG, MacDonald PE. PI3 kinases p110α and PI3K-C2β negatively regulate cAMP via PDE3/8 to control insulin secretion in mouse and human islets. Mol Metab 2016; 5:459-471. [PMID: 27408772 PMCID: PMC4921792 DOI: 10.1016/j.molmet.2016.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 04/26/2016] [Accepted: 05/04/2016] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES Phosphatidylinositol-3-OH kinase (PI3K) signalling in the endocrine pancreas contributes to glycaemic control. However, the mechanism by which PI3K modulates insulin secretion from the pancreatic beta cell is poorly understood. Thus, our objective was two-fold; to determine the signalling pathway by which acute PI3K inhibition enhances glucose-stimulated insulin secretion (GSIS) and to examine the role of this pathway in islets from type-2 diabetic (T2D) donors. METHODS Isolated islets from mice and non-diabetic or T2D human donors, or INS 832/13 cells, were treated with inhibitors of PI3K and/or phosphodiesterases (PDEs). The expression of PI3K-C2β was knocked down using siRNA. We measured insulin release, single-cell exocytosis, intracellular Ca(2+) responses ([Ca(2+)]i) and Ca(2+) channel currents, intracellular cAMP concentrations ([cAMP]i), and activation of cAMP-dependent protein kinase A (PKA) and protein kinase B (PKB/AKT). RESULTS The non-specific PI3K inhibitor wortmannin amplifies GSIS, raises [cAMP]i and activates PKA, but is without effect in T2D islets. Direct inhibition of specific PDE isoforms demonstrates a role for PDE3 (in humans and mice) and PDE8 (in mice) downstream of PI3K, and restores glucose-responsiveness of T2D islets. We implicate a role for the Class II PI3K catalytic isoform PI3K-C2β in this effect by limiting beta cell exocytosis. CONCLUSIONS PI3K limits GSIS via PDE3 in human islets. While inhibition of p110α or PIK-C2β signalling per se, may promote nutrient-stimulated insulin release, we now suggest that this signalling pathway is perturbed in islets from T2D donors.
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Affiliation(s)
- Jelena Kolic
- Department of Pharmacology, and the Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada.
| | - Jocelyn E Manning Fox
- Department of Pharmacology, and the Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Oleg G Chepurny
- Department of Medicine, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA
| | - Aliya F Spigelman
- Department of Pharmacology, and the Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Mourad Ferdaoussi
- Department of Pharmacology, and the Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
| | - Frank Schwede
- BIOLOG Life Science Institute, 28199 Bremen, Germany
| | - George G Holz
- Department of Medicine, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA; Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA
| | - Patrick E MacDonald
- Department of Pharmacology, and the Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
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19
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Meisenberg A, Kaschuba D, Balfanz S, Jordan N, Baumann A. Molecular and functional profiling of histamine receptor-mediated calcium ion signals in different cell lines. Anal Biochem 2015; 486:96-101. [PMID: 26151682 DOI: 10.1016/j.ab.2015.06.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/16/2015] [Accepted: 06/30/2015] [Indexed: 11/30/2022]
Abstract
Calcium ions (Ca(2+)) play a pivotal role in cellular physiology. Often Ca(2+)-dependent processes are studied in commonly available cell lines. To induce Ca(2+) signals on demand, cells may need to be equipped with additional proteins. A prominent group of membrane proteins evoking Ca(2+) signals are G-protein coupled receptors (GPCRs). These proteins register external signals such as photons, odorants, and neurotransmitters and convey ligand recognition into cellular responses, one of which is Ca(2+) signaling. To avoid receptor cross-talk or cross-activation with introduced proteins, the repertoire of cell-endogenous receptors must be known. Here we examined the presence of histamine receptors in six cell lines frequently used as hosts to study cellular signaling processes. In a concentration-dependent manner, histamine caused a rise in intracellular Ca(2+) in HeLa, HEK 293, and COS-1 cells. The concentration for half-maximal activation (EC50) was in the low micromolar range. In individual cells, transient Ca(2+) signals and Ca(2+) oscillations were uncovered. The results show that (i) HeLa, HEK 293, and COS-1 cells express sufficient amounts of endogenous receptors to study cellular Ca(2+) signaling processes directly and (ii) these cell lines are suitable for calibrating Ca(2+) biosensors in situ based on histamine receptor evoked responses.
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Affiliation(s)
- Annika Meisenberg
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Dagmar Kaschuba
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Sabine Balfanz
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Nadine Jordan
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Arnd Baumann
- Institute of Complex Systems, Cellular Biophysics (ICS-4), Forschungszentrum Jülich, D-52425 Jülich, Germany.
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20
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Tengholm A, Idevall-Hagren O. Imaging sub-plasma membrane cAMP dynamics with fluorescent translocation reporters. Methods Mol Biol 2015; 1294:85-101. [PMID: 25783879 DOI: 10.1007/978-1-4939-2537-7_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Imaging cAMP dynamics in single cells and tissues can provide important insights into the regulation of a variety of cellular processes. In recent years, a large number of tools for cAMP measurements have been developed. While most cAMP reporters are designed to undergo changes in fluorescence resonance energy transfer (FRET), there are alternative techniques with advantages for certain applications. Here, we describe protocols for cAMP measurements in the sub-plasma membrane space based on the detection of the cAMP-induced translocation of engineered fluorescent protein-tagged subunits of protein kinase A between the cytoplasm and the plasma membrane. Total internal reflection fluorescence (TIRF) imaging of the changes in reporter localization yields robust signal changes and has contributed to the discovery of cAMP oscillations in the sub-plasma membrane space of insulin-secreting β-cells stimulated with glucose and gluco-incretin hormones. We also demonstrate how the technique can be combined with measurements of the cytosolic Ca(2+) concentration or with recordings of the subcellular localization of the cAMP effector protein Epac2. The translocation reporter approach provides a valuable complement to other methods for imaging sub-membrane cAMP dynamics in various types of cells.
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Affiliation(s)
- Anders Tengholm
- Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Husargatan 3, Box 571, 751 23, Uppsala, Sweden,
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21
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Rich TC, Webb KJ, Leavesley SJ. Can we decipher the information content contained within cyclic nucleotide signals? J Gen Physiol 2014; 143:17-27. [PMID: 24378904 PMCID: PMC3874573 DOI: 10.1085/jgp.201311095] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Thomas C. Rich
- Center for Lung Biology, Department of Pharmacology, Basic Medical Sciences Graduate Program, and Department of Pharmacology, College of Medicine; and Department of Chemical and Biomolecular Engineering, College of Engineering, University of South Alabama, Mobile, AL 36688
| | - Kristal J. Webb
- Center for Lung Biology, Department of Pharmacology, Basic Medical Sciences Graduate Program, and Department of Pharmacology, College of Medicine; and Department of Chemical and Biomolecular Engineering, College of Engineering, University of South Alabama, Mobile, AL 36688
| | - Silas J. Leavesley
- Center for Lung Biology, Department of Pharmacology, Basic Medical Sciences Graduate Program, and Department of Pharmacology, College of Medicine; and Department of Chemical and Biomolecular Engineering, College of Engineering, University of South Alabama, Mobile, AL 36688
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22
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Mokhtari D, Al-Amin A, Turpaev K, Li T, Idevall-Hagren O, Li J, Wuttke A, Fred RG, Ravassard P, Scharfmann R, Tengholm A, Welsh N. Imatinib mesilate-induced phosphatidylinositol 3-kinase signalling and improved survival in insulin-producing cells: role of Src homology 2-containing inositol 5'-phosphatase interaction with c-Abl. Diabetologia 2013; 56:1327-38. [PMID: 23462796 DOI: 10.1007/s00125-013-2868-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 02/01/2013] [Indexed: 01/26/2023]
Abstract
AIMS/HYPOTHESIS It is not clear how small tyrosine kinase inhibitors, such as imatinib mesilate, protect against diabetes and beta cell death. The aim of this study was to determine whether imatinib, as compared with the non-cAbl-inhibitor sunitinib, affects pro-survival signalling events in the phosphatidylinositol 3-kinase (PI3K) pathway. METHODS Human EndoC-βH1 cells, murine beta TC-6 cells and human pancreatic islets were used for immunoblot analysis of insulin receptor substrate (IRS)-1, Akt and extracellular signal-regulated kinase (ERK) phosphorylation. Phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] plasma membrane concentrations were assessed in EndoC-βH1 and MIN6 cells using evanescent wave microscopy. Src homology 2-containing inositol 5'-phosphatase 2 (SHIP2) tyrosine phosphorylation and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) serine phosphorylation, as well as c-Abl co-localisation with SHIP2, were studied in HEK293 and EndoC-βH1 cells by immunoprecipitation and immunoblot analysis. Gene expression was assessed using RT-PCR. Cell viability was measured using vital staining. RESULTS Imatinib stimulated ERK(thr202/tyr204) phosphorylation in a c-Abl-dependent manner. Imatinib, but not sunitinib, also stimulated IRS-1(tyr612), Akt(ser473) and Akt(thr308) phosphorylation. This effect was paralleled by oscillatory bursts in plasma membrane PI(3,4,5)P3 levels. Wortmannin induced a decrease in PI(3,4,5)P3 levels, which was slower in imatinib-treated cells than in control cells, indicating an effect on PI(3,4,5)P3-degrading enzymes. In line with this, imatinib decreased the phosphorylation of SHIP2 but not of PTEN. c-Abl co-immunoprecipitated with SHIP2 and its binding to SHIP2 was largely reduced by imatinib but not by sunitinib. Imatinib increased total β-catenin levels and cell viability, whereas sunitinib exerted negative effects on cell viability. CONCLUSIONS/INTERPRETATION Imatinib inhibition of c-Abl in beta cells decreases SHIP2 activity, which results in enhanced signalling downstream of PI3 kinase.
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Affiliation(s)
- D Mokhtari
- Science for Life Laboratory, Department of Medical Cell Biology, Uppsala University, Biomedicum, PO Box 571, 751 23 Uppsala, Sweden
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Ford KJ, Arroyo DA, Kay JN, Lloyd EE, Bryan RM, Sanes JR, Feller MB. A role for TREK1 in generating the slow afterhyperpolarization in developing starburst amacrine cells. J Neurophysiol 2013; 109:2250-9. [PMID: 23390312 DOI: 10.1152/jn.01085.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Slow afterhyperpolarizations (sAHPs) play an important role in establishing the firing pattern of neurons that in turn influence network activity. sAHPs are mediated by calcium-activated potassium channels. However, the molecular identity of these channels and the mechanism linking calcium entry to their activation are still unknown. Here we present several lines of evidence suggesting that the sAHPs in developing starburst amacrine cells (SACs) are mediated by two-pore potassium channels. First, we use whole cell and perforated patch voltage clamp recordings to characterize the sAHP conductance under different pharmacological conditions. We find that this conductance was calcium dependent, reversed at EK, blocked by barium, insensitive to apamin and TEA, and activated by arachidonic acid. In addition, pharmacological inhibition of calcium-activated phosphodiesterase reduced the sAHP. Second, we performed gene profiling on isolated SACs and found that they showed strong preferential expression of the two-pore channel gene kcnk2 that encodes TREK1. Third, we demonstrated that TREK1 knockout animals exhibited an altered frequency of retinal waves, a frequency that is set by the sAHPs in SACs. With these results, we propose a model in which depolarization-induced decreases in cAMP lead to disinhibition of the two-pore potassium channels and in which the kinetics of this biochemical pathway dictate the slow activation and deactivation of the sAHP conductance. Our model offers a novel pathway for the activation of a conductance that is physiologically important.
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Affiliation(s)
- Kevin J Ford
- Department of Molecular and Cellular Biology, University of California, Berkeley, CA, USA
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Abstract
Insulin secretion from pancreatic β-cells is tightly regulated by glucose and other nutrients, hormones, and neural factors. The exocytosis of insulin granules is triggered by an elevation of the cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) and is further amplified by cyclic AMP (cAMP). Cyclic AMP is formed primarily in response to glucoincretin hormones and other G(s)-coupled receptor agonists, but generation of the nucleotide is critical also for an optimal insulin secretory response to glucose. Nutrient and receptor stimuli trigger oscillations of the cAMP concentration in β-cells. The oscillations arise from variations in adenylyl cyclase-mediated cAMP production and phosphodiesterase-mediated degradation, processes controlled by factors like cell metabolism and [Ca(2+)](i). Protein kinase A and the guanine nucleotide exchange factor Epac2 mediate the actions of cAMP in β-cells and operate at multiple levels to promote exocytosis and pulsatile insulin secretion. The cAMP signaling system contains important targets for pharmacological improvement of insulin secretion in type 2 diabetes.
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Affiliation(s)
- Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre , Box 571, SE-751 23 Uppsala, Sweden.
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