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Zhang R, Yao B, Li R, Limesand SW, Zhao Y, Chen X. Chronic Epinephrine-Induced Endoplasmic Reticulum and Oxidative Stress Impairs Pancreatic β-Cells Function and Fate. Int J Mol Sci 2024; 25:7029. [PMID: 39000139 PMCID: PMC11241606 DOI: 10.3390/ijms25137029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/13/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024] Open
Abstract
Epinephrine influences the function of pancreatic β-cells, primarily through the α2A-adrenergic receptor (α2A-AR) on their plasma membrane. Previous studies indicate that epinephrine transiently suppresses insulin secretion, whereas prolonged exposure induces its compensatory secretion. Nonetheless, the impact of epinephrine-induced α2A-AR signaling on the survival and function of pancreatic β-cells, particularly the impact of reprogramming after their removal from sustained epinephrine stimulation, remains elusive. In the present study, we applied MIN6, a murine insulinoma cell line, with 3 days of high concentration epinephrine incubation and 2 days of standard incubation, explored cell function and activity, and analyzed relevant regulatory pathways. The results showed that chronic epinephrine incubation led to the desensitization of α2A-AR and enhanced insulin secretion. An increased number of docked insulin granules and impaired Syntaxin-2 was found after chronic epinephrine exposure. Growth curve and cell cycle analyses showed the inhibition of cell proliferation. Transcriptome analysis showed the occurrence of endoplasmic reticulum stress (ER stress) and oxidative stress, such as the presence of BiP, CHOP, IRE1, ATF4, and XBP, affecting cellular endoplasmic reticulum function and survival, along with UCP2, OPA1, PINK, and PRKN, associated with mitochondrial dysfunction. Consequently, we conclude that chronic exposure to epinephrine induces α2A-AR desensitization and leads to ER and oxidative stress, impairing protein processing and mitochondrial function, leading to modified pancreatic β-cell secretory function and cell fate.
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Affiliation(s)
- Ran Zhang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Bingpeng Yao
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Rui Li
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Sean W Limesand
- School of Animal and Comparative Biomedical Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - Yongju Zhao
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
| | - Xiaochuan Chen
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
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2
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Moustaki M, Paschou SA, Vakali E, Xekouki P, Ntali G, Kassi E, Peppa M, Psaltopoulou T, Tzanela M, Vryonidou A. Secondary diabetes mellitus in pheochromocytomas and paragangliomas. Endocrine 2023; 82:467-479. [PMID: 37731140 PMCID: PMC10618385 DOI: 10.1007/s12020-023-03492-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 08/10/2023] [Indexed: 09/22/2023]
Abstract
Secondary diabetes mellitus (DM) in secretory pheochromocytomas and paragangliomas (PPGLs) is encountered in up to 50% of cases, with its presentation ranging from mild, insulin resistant forms to profound insulin deficiency states, such as diabetic ketoacidosis and hyperglycemic hyperosmolar state. PPGLs represent hypermetabolic states, in which adrenaline and noradrenaline induce insulin resistance in target tissues characterized by aerobic glycolysis, excessive lipolysis, altered adipokine expression, subclinical inflammation, as well as enhanced gluconeogenesis and glucogenolysis. These effects are mediated both directly, upon adrenergic receptor stimulation, and indirectly, via increased glucagon secretion. Impaired insulin secretion is the principal pathogenetic mechanism of secondary DM in this setting; yet, this is relevant for tumors with adrenergic phenotype, arising from direct inhibitory actions in beta pancreatic cells and incretin effect impairment. In contrast, insulin secretion might be enhanced in tumors with noradrenergic phenotype. This dimorphic effect might correspond to two distinct glycemic phenotypes, with predominant insulin resistance and insulin deficiency respectively. Secondary DM improves substantially post-surgery, with up to 80% remission rate. The fact that surgical treatment of PPGLs restores insulin sensitivity and secretion at greater extent compared to alpha and beta blockade, implies the existence of further, non-adrenergic mechanisms, possibly involving other hormonal co-secretion by these tumors. DM management in PPGLs is scarcely studied. The efficacy and safety of newer anti-diabetic medications, such as glucagon-like peptide 1 receptor agonists and sodium glucose cotransporter 2 inhibitors (SGLT2is), as well as potential disease-modifying roles of metformin and SGLT2is warrant further investigation in future studies.
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Affiliation(s)
- Melpomeni Moustaki
- Department of Endocrinology and Diabetes Center, Hellenic Red Cross Hospital, Athens, Greece
| | - Stavroula A Paschou
- Endocrine Unit and Diabetes Center, Department of Clinical Therapeutics, Alexandra Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.
| | - Elena Vakali
- Department of Endocrinology and Diabetes Center, Hellenic Red Cross Hospital, Athens, Greece
| | - Paraskevi Xekouki
- Department of Endocrinology and Diabetes, University General Hospital of Heraklion, School of Medicine, University of Crete, Heraklion, Greece
| | - Georgia Ntali
- Department of Endocrinology and Diabetes Center, Endo ERN Center, Evaggelismos Hospital, Athens, Greece
| | - Evanthia Kassi
- Endocrine Unit, First Department of Propaedeutic and Internal Medicine, Laiko Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Melpomeni Peppa
- Endocrine Unit and Diabetes Center, Second Department of Internal Medicine, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Theodora Psaltopoulou
- Endocrine Unit and Diabetes Center, Department of Clinical Therapeutics, Alexandra Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Marinella Tzanela
- Department of Endocrinology and Diabetes Center, Endo ERN Center, Evaggelismos Hospital, Athens, Greece
| | - Andromachi Vryonidou
- Department of Endocrinology and Diabetes Center, Hellenic Red Cross Hospital, Athens, Greece
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3
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Vydra Bousova K, Zouharova M, Jiraskova K, Vetyskova V. Interaction of Calmodulin with TRPM: An Initiator of Channel Modulation. Int J Mol Sci 2023; 24:15162. [PMID: 37894842 PMCID: PMC10607381 DOI: 10.3390/ijms242015162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Transient receptor potential melastatin (TRPM) channels, a subfamily of the TRP superfamily, constitute a diverse group of ion channels involved in mediating crucial cellular processes like calcium homeostasis. These channels exhibit complex regulation, and one of the key regulatory mechanisms involves their interaction with calmodulin (CaM), a cytosol ubiquitous calcium-binding protein. The association between TRPM channels and CaM relies on the presence of specific CaM-binding domains in the channel structure. Upon CaM binding, the channel undergoes direct and/or allosteric structural changes and triggers down- or up-stream signaling pathways. According to current knowledge, ion channel members TRPM2, TRPM3, TRPM4, and TRPM6 are directly modulated by CaM, resulting in their activation or inhibition. This review specifically focuses on the interplay between TRPM channels and CaM and summarizes the current known effects of CaM interactions and modulations on TRPM channels in cellular physiology.
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4
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Irelan D, Boyd A, Fiedler E, Lochmaier P, McDonough W, Aragon IV, Rachek L, Abou Saleh L, Richter W. Acute PDE4 Inhibition Induces a Transient Increase in Blood Glucose in Mice. Int J Mol Sci 2023; 24:ijms24043260. [PMID: 36834669 PMCID: PMC9963939 DOI: 10.3390/ijms24043260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
cAMP-phosphodiesterase 4 (PDE4) inhibitors are currently approved for the treatment of inflammatory diseases. There is interest in expanding the therapeutic application of PDE4 inhibitors to metabolic disorders, as their chronic application induces weight loss in patients and animals and improves glucose handling in mouse models of obesity and diabetes. Unexpectedly, we have found that acute PDE4 inhibitor treatment induces a temporary increase, rather than a decrease, in blood glucose levels in mice. Blood glucose levels in postprandial mice increase rapidly upon drug injection, reaching a maximum after ~45 min, and returning to baseline within ~4 h. This transient blood glucose spike is replicated by several structurally distinct PDE4 inhibitors, suggesting that it is a class effect of PDE4 inhibitors. PDE4 inhibitor treatment does not reduce serum insulin levels, and the subsequent injection of insulin potently reduces PDE4 inhibitor-induced blood glucose levels, suggesting that the glycemic effects of PDE4 inhibition are independent of changes in insulin secretion and/or sensitivity. Conversely, PDE4 inhibitors induce a rapid reduction in skeletal muscle glycogen levels and potently inhibit the uptake of 2-deoxyglucose into muscle tissues. This suggests that reduced glucose uptake into muscle tissue is a significant contributor to the transient glycemic effects of PDE4 inhibitors in mice.
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Affiliation(s)
- Daniel Irelan
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Abigail Boyd
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Edward Fiedler
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Peter Lochmaier
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Will McDonough
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Ileana V. Aragon
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Lyudmila Rachek
- Department of Pharmacology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Lina Abou Saleh
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
| | - Wito Richter
- Department of Biochemistry & Molecular Biology and Center for Lung Biology, Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USA
- Correspondence:
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Sluga N, Križančić Bombek L, Kerčmar J, Sarikas S, Postić S, Pfabe J, Skelin Klemen M, Korošak D, Stožer A, Slak Rupnik M. Physiological levels of adrenaline fail to stop pancreatic beta cell activity at unphysiologically high glucose levels. Front Endocrinol (Lausanne) 2022; 13:1013697. [PMID: 36387857 PMCID: PMC9640998 DOI: 10.3389/fendo.2022.1013697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 10/07/2022] [Indexed: 01/11/2023] Open
Abstract
Adrenaline inhibits insulin secretion from pancreatic beta cells to allow an organism to cover immediate energy needs by unlocking internal nutrient reserves. The stimulation of α2-adrenergic receptors on the plasma membrane of beta cells reduces their excitability and insulin secretion mostly through diminished cAMP production and downstream desensitization of late step(s) of exocytotic machinery to cytosolic Ca2+ concentration ([Ca2+]c). In most studies unphysiologically high adrenaline concentrations have been used to evaluate the role of adrenergic stimulation in pancreatic endocrine cells. Here we report the effect of physiological adrenaline levels on [Ca2+]c dynamics in beta cell collectives in mice pancreatic tissue slice preparation. We used confocal microscopy with a high spatial and temporal resolution to evaluate glucose-stimulated [Ca2+]c events and their sensitivity to adrenaline. We investigated glucose concentrations from 8-20 mM to assess the concentration of adrenaline that completely abolishes [Ca2+]c events. We show that 8 mM glucose stimulation of beta cell collectives is readily inhibited by the concentration of adrenaline available under physiological conditions, and that sequent stimulation with 12 mM glucose or forskolin in high nM range overrides this inhibition. Accordingly, 12 mM glucose stimulation required at least an order of magnitude higher adrenaline concentration above the physiological level to inhibit the activity. To conclude, higher glucose concentrations stimulate beta cell activity in a non-linear manner and beyond levels that could be inhibited with physiologically available plasma adrenaline concentration.
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Affiliation(s)
- Nastja Sluga
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | | | - Jasmina Kerčmar
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Srdjan Sarikas
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sandra Postić
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Johannes Pfabe
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Maša Skelin Klemen
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Dean Korošak
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Andraž Stožer
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Marjan Slak Rupnik
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Alma Mater Europaea, European Center Maribor, Maribor, Slovenia
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Luo Y, Chen S, Wu F, Jiang C, Fang M. The identification of the key residues E829 and R845 involved in transient receptor potential melastatin 2 channel gating. Front Aging Neurosci 2022; 14:1033434. [DOI: 10.3389/fnagi.2022.1033434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/03/2022] [Indexed: 11/13/2022] Open
Abstract
Transient receptor potential melastatin 2 (TRPM2), a non-selective cation channel, is involved in many physiological and pathological processes, including temperature sensing, synaptic plasticity regulation, and neurodegenerative diseases. However, the gating mechanism of TRPM2 channel is complex, which hinders its functional research. With the discovery of the Ca2+ binding site in the S2–S3 domain of TRPM2 channel, more and more attention has been drawn to the role of the transmembrane segments in channel gating. In this study, we focused on the D820-F867 segment around the S2 domain, and identified the key residues on it. Functional assays of the deletion mutants displayed that the deletions of D820-W835 and L836-P851 destroyed channel function totally, indicating the importance of these two segments. Sequence alignments on them found three polar and charged residues with high conservation (D820, E829, and R845). D820A, E829A, and R845A which removed the charge and the side chain of the residues were tested by 500 μM adenosine diphosphate-ribose (ADPR) or 50 mM Ca2+. E829A and R845A affected the characteristic of channel currents, while D820A behaved similarly to WT, indicating the participations of E829 and R845 in channel gating. The charge reversing mutants, E829K and R845D were then constructed and the electrophysiological tests showed that E829A and E829K made the channel lose function. Interestingly, R845A and R845D exhibited an inactivation process when using 500 μM ADPR, but activated normally by 50 mM Ca2+. Our data suggested that the negative charge at E829 took a vital part in channel activation, and R845 increased the stability of the Ca2+ combination in S2-S3 domain, thus guaranteeing the opening of TRPM2 channel. In summary, our identification of the key residues E829 and R845 in the transmembrane segments of TRPM2. By exploring the gating process of TRPM2 channel, our work helps us better understand the mechanism of TRPM2 as a potential biomarker in neurodegenerative diseases, and provides a new approach for the prediction, diagnosis, and prognosis of neurodegenerative diseases.
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Hu W, Yan G, Ding Q, Cai J, Zhang Z, Zhao Z, Lei H, Zhu YZ. Update of Indoles: Promising molecules for ameliorating metabolic diseases. Biomed Pharmacother 2022; 150:112957. [PMID: 35462330 DOI: 10.1016/j.biopha.2022.112957] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/30/2022] [Accepted: 04/11/2022] [Indexed: 11/15/2022] Open
Abstract
Obesity and metabolic disorders have gradually become public health-threatening problems. The metabolic disorder is a cluster of complex metabolic abnormalities which are featured by dysfunction in glucose and lipid metabolism, and results from the increasing prevalence of visceral obesity. With the core driving factor of insulin resistance, metabolic disorder mainly includes type 2 diabetes mellitus (T2DM), micro and macro-vascular diseases, non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and the dysfunction of gut microbiota. Strategies and therapeutic attention are demanded to decrease the high risk of metabolic diseases, from lifestyle changes to drug treatment, especially herbal medicines. Indole is a parent substance of numerous bioactive compounds, and itself can be produced by tryptophan catabolism to stimulate glucagon-like peptide-1 (GLP-1) secretion and inhibit the development of obesity. In addition, in heterocycles drug discovery, the indole scaffold is primarily found in natural compounds with versatile biological activity and plays a prominent role in drug molecules synthesis. In recent decades, plenty of natural or synthesized indole deriviatives have been investigated and elucidated to exert effects on regulating glucose hemeostasis and lipd metabolism. The aim of this review is to trace and emphasize the compounds containing indole scaffold that possess immense potency on preventing metabolic disorders, particularly T2DM, obesity and NAFLD, along with the underlying molecular mechanisms, therefore facilitate a better comprehension of their druggability and application in metabolic diseases.
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Affiliation(s)
- Wei Hu
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Guanyu Yan
- Department of Allergy and Clinical Immunology, National Center for Respiratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, Guangzhou, China
| | - Qian Ding
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Jianghong Cai
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Zhongyi Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Ziming Zhao
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China
| | - Heping Lei
- Guangdong Provincial Key Laboratory of Coronary Heart Disease Prevention, Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
| | - Yi Zhun Zhu
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine and School of Pharmacy, Macau University of Science and Technology, Macau, China; Shanghai Key Laboratory of Bioactive Small Molecules, School of Pharmacy, Fudan University, Shanghai, China.
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Funazaki S, Yoshida M, Yamada H, Kakei M, Kawakami M, Nagashima S, Hara K, Dezaki K. A novel mechanism of imeglimin-mediated insulin secretion via the cADPR-TRP channel pathway. J Diabetes Investig 2022; 13:34-41. [PMID: 34523242 PMCID: PMC8756313 DOI: 10.1111/jdi.13669] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/02/2021] [Accepted: 09/12/2021] [Indexed: 01/20/2023] Open
Abstract
AIMS/INTRODUCTION Imeglimin is a novel oral hypoglycemic agent that improves blood glucose levels through multiple mechanisms of action including the enhancement of glucose-stimulated insulin secretion (GSIS), however, the details of this mechanism have not been clarified. In the process of GSIS, activation of the transient receptor potential melastatin 2 (TRPM2) channel, a type of non-selective cation channel (NSCCs) in β-cells, promotes plasma membrane depolarization. The present study aimed to examine whether imeglimin potentiates GSIS via the TRPM2 channel in β-cells. MATERIALS AND METHODS Pancreatic islets were isolated by collagenase digestion from male wild-type and TRPM2-knockout (KO) mice. Insulin release and nicotinamide adenine dinucleotide (NAD+ ) production in islets were measured under static incubation. NSCC currents in mouse single β-cells were measured by patch-clamp experiments. RESULTS Batch-incubation studies showed that imeglimin enhanced GSIS at stimulatory 16.6 mM glucose, whereas it did not affect basal insulin levels at 2.8 mM glucose. Imeglimin increased the glucose-induced production of NAD+ , a precursor of cADPR, in islets and the insulinotropic effects of imeglimin were attenuated by a cADPR inhibitor 8-Br-cADPR. Furthermore, imeglimin increased NSCC current in β-cells, and abolished this current in TRPM2-KO mice. Imeglimin did not potentiate GSIS in the TRPM2-KO islets, suggesting that imeglimin's increase of NSCC currents through the TRPM2 channel is causally implicated in its insulin releasing effects. CONCLUSIONS Imeglimin may activate TRPM2 channels in β-cells via the production of NAD+ /cADPR, leading to the potentiation of GSIS. Developing approaches to stimulate cADPR-TRPM2 signaling provides a potential therapeutic tool to treat type 2 diabetes.
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Affiliation(s)
- Shunsuke Funazaki
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Masashi Yoshida
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Hodaka Yamada
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Masafumi Kakei
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Masanobu Kawakami
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Shuichi Nagashima
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Kazuo Hara
- Department of MedicineDivision of Endocrinology and MetabolismJichi Medical University Saitama Medical CenterSaitamaJapan
| | - Katsuya Dezaki
- Department of PhysiologyDivision of Integrative PhysiologyJichi Medical UniversityShimotsuke‐shiJapan
- Faculty of PharmacyIryo Sosei UniversityIwakiJapan
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Lin RJ, Yen YK, Lee CH, Hsieh SL, Chang YC, Juan YS, Long CY, Shen KP, Wu BN. Eugenosedin-A improves obesity-related hyperglycemia by regulating ATP-sensitive K + channels and insulin secretion in pancreatic β cells. Biomed Pharmacother 2021; 145:112447. [PMID: 34808553 DOI: 10.1016/j.biopha.2021.112447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/08/2021] [Accepted: 11/16/2021] [Indexed: 12/31/2022] Open
Abstract
Eugenosedin-A (Eu-A) has been shown to protect against hyperglycemia- and hyperlipidemia-induced metabolic syndrome. We investigated the relationship of KATP channel activities and insulin secretion by Eu-A in vitro in pancreatic β-cells, and examined the effect of Eu-A on streptozotocin (STZ)/nicotinamide (NA)-induced type 2 diabetes mellitus (T2DM) in vivo. We isolated pancreatic islets from adult male Wistar rats (250-350 g) and identified pancreatic β-cells by the cell size, capacitance and membrane potential. Perforated patch-clamp and inside-out recordings were used to monitor the membrane potential (current-clamp mode) and channel activity (voltage-clamp mode) of β-cells. The membrane potential of β-cells was raised by Eu-A and reversed by the KATP channel activator diazoxide. Eu-A inhibited the KATP channel activity measured at - 60 mV and increased the intracellular calcium concentration ([Ca2+]i), resulting in enhanced insulin secretion. Eu-A also reduced Kir6.2 protein on the cell membrane and scattered in the cytosol under normal glucose conditions (5.6 mM). In our animal study, rats were divided into normal and STZ/NA-induced T2DM groups. Normal rats fed with regular chow were divided into control and control+Eu-A (5 mg/kg/day, i.p.) groups. The STZ/NA-induced diabetic rats fed with a high-fat diet (HFD) were divided into three groups: T2DM, T2DM+Eu-A (5 mg/kg/day, i.p.), and T2DM+glibenclamide (0.5 mg/kg/day, i.p.; a KATP channel inhibitor). Both Eu-A and glibenclamide decreased the rats' blood glucose, prevented weight gain, and enhanced insulin secretion. We found that Eu-A blocked pancreatic β-cell KATP channels, caused membrane potential depolarization, and stimulated Ca2+ influx, thus increasing insulin secretion. Furthermore, Eu-A decreased blood glucose and increased insulin levels in T2DM rats. These results suggested that Eu-A might have clinical benefits for the control of T2DM and its complications.
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Affiliation(s)
- Rong-Jyh Lin
- Department of Parasitology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Yu-Kwan Yen
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Chien-Hsing Lee
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan; Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Su-Ling Hsieh
- Department of Pharmacy, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Yu-Chin Chang
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Yung-Shun Juan
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Cheng-Yu Long
- Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Kuo-Ping Shen
- Department of Nursing, Meiho University, Pingtung 912, Taiwan.
| | - Bin-Nan Wu
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan; Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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10
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Stožer A, Paradiž Leitgeb E, Pohorec V, Dolenšek J, Križančić Bombek L, Gosak M, Skelin Klemen M. The Role of cAMP in Beta Cell Stimulus-Secretion and Intercellular Coupling. Cells 2021; 10:1658. [PMID: 34359828 PMCID: PMC8304079 DOI: 10.3390/cells10071658] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/18/2021] [Accepted: 06/28/2021] [Indexed: 12/22/2022] Open
Abstract
Pancreatic beta cells secrete insulin in response to stimulation with glucose and other nutrients, and impaired insulin secretion plays a central role in development of diabetes mellitus. Pharmacological management of diabetes includes various antidiabetic drugs, including incretins. The incretin hormones, glucagon-like peptide-1 and gastric inhibitory polypeptide, potentiate glucose-stimulated insulin secretion by binding to G protein-coupled receptors, resulting in stimulation of adenylate cyclase and production of the secondary messenger cAMP, which exerts its intracellular effects through activation of protein kinase A or the guanine nucleotide exchange protein 2A. The molecular mechanisms behind these two downstream signaling arms are still not fully elucidated and involve many steps in the stimulus-secretion coupling cascade, ranging from the proximal regulation of ion channel activity to the central Ca2+ signal and the most distal exocytosis. In addition to modifying intracellular coupling, the effect of cAMP on insulin secretion could also be at least partly explained by the impact on intercellular coupling. In this review, we systematically describe the possible roles of cAMP at these intra- and inter-cellular signaling nodes, keeping in mind the relevance for the whole organism and translation to humans.
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Affiliation(s)
- Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
| | - Eva Paradiž Leitgeb
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
| | - Viljem Pohorec
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
- Faculty of Natural Sciences and Mathematics, University of Maribor, SI-2000 Maribor, Slovenia
| | - Lidija Križančić Bombek
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
| | - Marko Gosak
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
- Faculty of Natural Sciences and Mathematics, University of Maribor, SI-2000 Maribor, Slovenia
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, SI-2000 Maribor, Slovenia; (A.S.); (E.P.L.); (V.P.); (J.D.); (L.K.B.); (M.G.)
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11
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Snow SJ, Henriquez AR, Fisher A, Vallanat B, House JS, Schladweiler MC, Wood CE, Kodavanti UP. Peripheral metabolic effects of ozone exposure in healthy and diabetic rats on normal or high-cholesterol diet. Toxicol Appl Pharmacol 2021; 415:115427. [PMID: 33524448 PMCID: PMC8086744 DOI: 10.1016/j.taap.2021.115427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/21/2022]
Abstract
Epidemiological studies show that individuals with underlying diabetes and diet-associated ailments are more susceptible than healthy individuals to adverse health effects of air pollution. Exposure to air pollutants can induce metabolic stress and increase cardiometabolic disease risk. Using male Wistar and Wistar-derived Goto-Kakizaki (GK) rats, which exhibit a non-obese type-2 diabetes phenotype, we investigated whether two key metabolic stressors, type-2 diabetes and a high-cholesterol atherogenic diet, exacerbate ozone-induced metabolic effects. Rats were fed a normal control diet (ND) or high-cholesterol diet (HCD) for 12 weeks and then exposed to filtered air or 1.0-ppm ozone (6 h/day) for 1 or 2 days. Metabolic responses were analyzed at the end of each day and after an 18-h recovery period following the 2-day exposure. In GK rats, baseline hyperglycemia and glucose intolerance were exacerbated by HCD vs. ND and by ozone vs. air. HCD also resulted in higher insulin in ozone-exposed GK rats and circulating lipase, aspartate transaminase, and alanine transaminase in all groups (Wistar>GK). Histopathological effects induced by HCD in the liver, which included macrovesicular vacuolation and hepatocellular necrosis, were more severe in Wistar vs. GK rats. Liver gene expression in Wistar and GK rats fed ND showed numerous strain differences, including evidence of increased lipid metabolizing activity and ozone-induced alterations in glucose and lipid transporters, specifically in GK rats. Collectively, these findings indicate that peripheral metabolic alterations induced by diabetes and high-cholesterol diet can enhance susceptibility to the metabolic effects of inhaled pollutants.
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MESH Headings
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/pathology
- Air Pollutants/toxicity
- Animals
- Biomarkers/blood
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Body Composition/drug effects
- Cholesterol, Dietary/metabolism
- Cholesterol, Dietary/toxicity
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/genetics
- Diet, High-Fat/adverse effects
- Disease Models, Animal
- Energy Metabolism/drug effects
- Gene Expression Regulation
- Inhalation Exposure
- Insulin/blood
- Lipids/blood
- Liver/drug effects
- Liver/metabolism
- Liver/pathology
- Male
- Ozone/toxicity
- Rats, Wistar
- Species Specificity
- Rats
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Affiliation(s)
- Samantha J Snow
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Andres R Henriquez
- Oak Ridge Institute for Science and Education Research Participation Program, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Anna Fisher
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Beena Vallanat
- Biomolecular and Computational Toxicology Division, Center for Computational Toxicology and Exposure, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - John S House
- Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, United States
| | - Mette C Schladweiler
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Charles E Wood
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States
| | - Urmila P Kodavanti
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States; Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, United States.
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12
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Kashio M. Thermosensation involving thermo-TRPs. Mol Cell Endocrinol 2021; 520:111089. [PMID: 33227348 DOI: 10.1016/j.mce.2020.111089] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 02/02/2020] [Accepted: 11/17/2020] [Indexed: 12/13/2022]
Abstract
The transient receptor potential (TRP) channels constitute a superfamily of large ion channels that are activated by a wide range of chemical, mechanical and thermal stimuli. TRP channels with temperature sensitivity are called thermo-TRPs. They are involved in diverse physiological functions through their detection of external environmental temperature and internal body temperature. Each thermo-TRP has its own characteristic temperature threshold for activation. As a group, they cover temperatures ranging from cold to nociceptive high temperatures. Recently, many studies have identified the functions of thermo-TRPs residing in deep organs where they are exposed to body temperature. Importantly, temperature thresholds of thermo-TRPs can be regulated by physiological factors enabling their function at relatively constant body temperature. Moreover, several thermo-TRPs are reportedly engaged in body temperature regulation. This review will summarize the current understanding of thermo-TRPs, including their roles in thermosensation and functional regulation of physiological responses at body temperature and the regulation of body temperature.
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Affiliation(s)
- Makiko Kashio
- Department of Physiology, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan.
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13
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Kalwat MA, Huang Z, Binns DD, McGlynn K, Cobb MH. α 2-Adrenergic Disruption of β Cell BDNF-TrkB Receptor Tyrosine Kinase Signaling. Front Cell Dev Biol 2020; 8:576396. [PMID: 33178692 PMCID: PMC7593622 DOI: 10.3389/fcell.2020.576396] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/14/2020] [Indexed: 12/11/2022] Open
Abstract
Adrenergic signaling is a well-known input into pancreatic islet function. Specifically, the insulin-secreting islet β cell expresses the Gi/o-linked α2-adrenergic receptor, which upon activation suppresses insulin secretion. The use of the adrenergic agonist epinephrine at micromolar doses may have supraphysiological effects. We found that pretreating β cells with micromolar concentrations of epinephrine differentially inhibited activation of receptor tyrosine kinases. We chose TrkB as an example because of its relative sensitivity to the effects of epinephrine and due to its potential regulatory role in the β cell. Our characterization of brain-derived neurotrophic factor (BDNF)-TrkB signaling in MIN6 β cells showed that TrkB is activated by BDNF as expected, leading to canonical TrkB autophosphorylation and subsequent downstream signaling, as well as chronic effects on β cell growth. Micromolar, but not nanomolar, concentrations of epinephrine blocked BDNF-induced TrkB autophosphorylation and downstream mitogen-activated protein kinase pathway activation, suggesting an inhibitory phenomenon at the receptor level. We determined epinephrine-mediated inhibition of TrkB activation to be Gi/o-dependent using pertussis toxin, arguing against an off-target effect of high-dose epinephrine. Published data suggested that inhibition of potassium channels or phosphoinositide-3-kinase signaling may abrogate the negative effects of epinephrine; however, these did not rescue TrkB signaling in our experiments. Taken together, these results show that (1) TrkB kinase signaling occurs in β cells and (2) use of epinephrine in studies of insulin secretion requires careful consideration of concentration-dependent effects. BDNF-TrkB signaling in β cells may underlie pro-survival or growth signaling and warrants further study.
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Affiliation(s)
- Michael A. Kalwat
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, United States
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14
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Henriquez AR, Snow SJ, Schladweiler MC, Miller CN, Kodavanti UP. Independent roles of beta-adrenergic and glucocorticoid receptors in systemic and pulmonary effects of ozone. Inhal Toxicol 2020; 32:155-169. [PMID: 32366144 DOI: 10.1080/08958378.2020.1759736] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Background: The release of catecholamines is preceded by glucocorticoids during a stress response. We have shown that ozone-induced pulmonary responses are mediated through the activation of stress hormone receptors.Objective: To examine the interdependence of beta-adrenergic (βAR) and glucocorticoid receptors (GRs), we inhibited βAR while inducing GR or inhibited GR while inducing βAR and examined ozone-induced stress response.Methods: Twelve-week-old male Wistar-Kyoto rats were pretreated daily with saline or propranolol (PROP; βAR-antagonist; 10 mg/kg-i.p.; starting 7-d prior to exposure) followed-by saline or dexamethasone (DEX) sulfate (GR-agonist; 0.02 mg/kg-i.p.; starting 1-d prior to exposure) and exposed to air or 0.8 ppm ozone (4 h/d × 2-d). In a second experiment, rats were similarly pretreated with corn-oil or mifepristone (MIFE; GR-antagonist, 30 mg/kg-s.c.) followed by saline or clenbuterol (CLEN; β2AR-agonist; 0.02 mg/kg-i.p.) and exposed.Results: DEX and PROP + DEX decreased adrenal, spleen and thymus weights in all rats. DEX and MIFE decreased and increased corticosterone, respectively. Ozone-induced pulmonary protein leakage, inflammation and IL-6 increases were inhibited by PROP or PROP + DEX and exacerbated by CLEN or CLEN + MIFE. DEX and ozone-induced while MIFE reversed lymphopenia (MIFE > CLEN + MIFE). DEX exacerbated while PROP, MIFE, or CLEN + MIFE inhibited ozone-induced hyperglycemia and glucose intolerance. Ozone inhibited glucose-mediated insulin release.Conclusions: In summary, 1) activating βAR, even with GR inhibition, exacerbated and inhibiting βAR, even with GR activation, attenuated ozone-induced pulmonary effects; and 2) activating GR exacerbated ozone systemic effects, but with βAR inhibition, this exacerbation was less remarkable. These data suggest the independent roles of βAR in pulmonary and dependent roles of βAR and GR in systemic effects of ozone.
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Affiliation(s)
- Andres R Henriquez
- Department of Energy, Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Samantha J Snow
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Mette C Schladweiler
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Colette N Miller
- Department of Energy, Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Urmila P Kodavanti
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
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15
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Islam MS. Molecular Regulations and Functions of the Transient Receptor Potential Channels of the Islets of Langerhans and Insulinoma Cells. Cells 2020; 9:cells9030685. [PMID: 32168890 PMCID: PMC7140661 DOI: 10.3390/cells9030685] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/06/2020] [Accepted: 03/08/2020] [Indexed: 12/17/2022] Open
Abstract
Insulin secretion from the β-cells of the islets of Langerhans is triggered mainly by nutrients such as glucose, and incretin hormones such as glucagon-like peptide-1 (GLP-1). The mechanisms of the stimulus-secretion coupling involve the participation of the key enzymes that metabolize the nutrients, and numerous ion channels that mediate the electrical activity. Several members of the transient receptor potential (TRP) channels participate in the processes that mediate the electrical activities and Ca2+ oscillations in these cells. Human β-cells express TRPC1, TRPM2, TRPM3, TRPM4, TRPM7, TRPP1, TRPML1, and TRPML3 channels. Some of these channels have been reported to mediate background depolarizing currents, store-operated Ca2+ entry (SOCE), electrical activity, Ca2+ oscillations, gene transcription, cell-death, and insulin secretion in response to stimulation by glucose and GLP1. Different channels of the TRP family are regulated by one or more of the following mechanisms: activation of G protein-coupled receptors, the filling state of the endoplasmic reticulum Ca2+ store, heat, oxidative stress, or some second messengers. This review briefly compiles our current knowledge about the molecular mechanisms of regulations, and functions of the TRP channels in the β-cells, the α-cells, and some insulinoma cell lines.
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Affiliation(s)
- Md. Shahidul Islam
- Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset, Research Center, 5th floor, SE-118 83 Stockholm, Sweden;
- Department of Emergency Care and Internal Medicine, Uppsala University Hospital, Uppsala University, SE-751 85 Uppsala, Sweden
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16
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Chapelot D, Charlot K. Physiology of energy homeostasis: Models, actors, challenges and the glucoadipostatic loop. Metabolism 2019; 92:11-25. [PMID: 30500561 DOI: 10.1016/j.metabol.2018.11.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/25/2018] [Accepted: 11/19/2018] [Indexed: 12/16/2022]
Abstract
The aim of this review is to discuss the physiology of energy homeostasis (EH), which is a debated concept. Thus, we will see that the set-point theory is highly challenged and that other models integrating an anticipative component, such as energy allostasis, seem more relevant to experimental reports and life preservation. Moreover, the current obesity epidemic suggests that EH is poorly efficient in the modern human dietary environment. Non-homeostatic phenomena linked to hedonism and reward seem to profoundly impair EH. In this review, the apparent failed homeostatic responses to energy challenges such as exercise, cafeteria diet, overfeeding and diet-induced weight loss, as well as their putative determinants, are analyzed to highlight the mechanisms of EH. Then, the hormonal, neuronal, and metabolic factors of energy intake or energy expenditure are briefly presented. Last, this review focuses on the contributions of two of the most pivotal and often overlooked determinants of EH: the availability of endogenous energy and the pattern of energy intake. A glucoadipostatic loop model is finally proposed to link energy stored in adipose tissue to EH through changes in eating behavior via leptin and sympathetic nervous system activity.
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Affiliation(s)
- Didier Chapelot
- Université Paris 13, Centre de Recherche en Epidémiologie et Statistique, Equipe de Recherche en Epidémiologie Nutritionnelle (EREN), Inserm (U1153), Inra (U1125), Cnam, Bobigny, France.
| | - Keyne Charlot
- Institut de Recherche Biomédicale des Armées, Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, Département Environnements Opérationnels, Brétigny-sur-Orge, France
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17
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Chronic d-serine supplementation impairs insulin secretion. Mol Metab 2018; 16:191-202. [PMID: 30093356 PMCID: PMC6157639 DOI: 10.1016/j.molmet.2018.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/07/2018] [Accepted: 07/16/2018] [Indexed: 12/20/2022] Open
Abstract
Objective The metabolic role of d-serine, a non-proteinogenic NMDA receptor co-agonist, is poorly understood. Conversely, inhibition of pancreatic NMDA receptors as well as loss of the d-serine producing enzyme serine racemase have been shown to modulate insulin secretion. Thus, we aim to study the impact of chronic and acute d-serine supplementation on insulin secretion and other parameters of glucose homeostasis. Methods We apply MALDI FT-ICR mass spectrometry imaging, NMR based metabolomics, 16s rRNA gene sequencing of gut microbiota in combination with a detailed physiological characterization to unravel the metabolic action of d-serine in mice acutely and chronically treated with 1% d-serine in drinking water in combination with either chow or high fat diet feeding. Moreover, we identify SNPs in SRR, the enzyme converting L-to d-serine and two subunits of the NMDA receptor to associate with insulin secretion in humans, based on the analysis of 2760 non-diabetic Caucasian individuals. Results We show that chronic elevation of d-serine results in reduced high fat diet intake. In addition, d-serine leads to diet-independent hyperglycemia due to blunted insulin secretion from pancreatic beta cells. Inhibition of alpha 2-adrenergic receptors rapidly restores glycemia and glucose tolerance in d-serine supplemented mice. Moreover, we show that single nucleotide polymorphisms (SNPs) in SRR as well as in individual NMDAR subunits are associated with insulin secretion in humans. Conclusion Thus, we identify a novel role of d-serine in regulating systemic glucose metabolism through modulating insulin secretion. d-serine suppresses HFD induced weight gain. d-serine supplementation impairs insulin secretion. d-serine effects on insulin secretion can be reverted by a2 adrenergic antagonists.
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18
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Luo Y, Yu X, Ma C, Luo J, Yang W. Identification of a Novel EF-Loop in the N-terminus of TRPM2 Channel Involved in Calcium Sensitivity. Front Pharmacol 2018; 9:581. [PMID: 29915540 PMCID: PMC5994415 DOI: 10.3389/fphar.2018.00581] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/15/2018] [Indexed: 01/10/2023] Open
Abstract
As an oxidative stress sensor, transient receptor potential melastatin 2 (TRPM2) channel is involved in many physiological and pathological processes including warmth sensing, ischemia injury, inflammatory diseases and diabetes. Intracellular calcium is critical for TRPM2 channel activation and the IQ-like motif in the N-terminus has been shown to be important by mediating calmodulin binding. Sequence analysis predicted two potential EF-loops in the N-terminus of TRPM2. Site-directed mutagenesis combining with functional assay showed that substitution with alanine of several residues, most of which are conserved in the typical EF-loop, including D267, D278, D288, and E298 dramatically reduced TRPM2 channel currents. By further changing the charges or side chain length of these conserved residues, our results indicate that the negative charge of D267 and the side chain length of D278 are critical for calcium-induced TRPM2 channel activation. G272I mutation also dramatically reduced the channel currents, suggesting that this site is critical for calcium-induced TRPM2 channel activation. Furthermore, D267A mutant dramatically reduced the currents induced by calcium alone compared with that by ADPR, indicating that D267 residue in D267–D278 motif is the most important site for calcium sensitivity of TRPM2. In addition, inside-out recordings showed that mutations at D267, G272, D278, and E298 had no effect on single-channel conductance. Taken together, our data indicate that D267–D278 motif in the N-terminus as a novel EF-loop is critical for calcium-induced TRPM2 channel activation.
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Affiliation(s)
- Yuhuan Luo
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiafei Yu
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Cheng Ma
- Co-facility Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhong Luo
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Yang
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
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19
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Rorsman P, Ashcroft FM. Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev 2018; 98:117-214. [PMID: 29212789 PMCID: PMC5866358 DOI: 10.1152/physrev.00008.2017] [Citation(s) in RCA: 433] [Impact Index Per Article: 72.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/30/2017] [Accepted: 06/18/2017] [Indexed: 12/14/2022] Open
Abstract
The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity, and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM.
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Affiliation(s)
- Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frances M Ashcroft
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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20
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Uchida K, Dezaki K, Yoneshiro T, Watanabe T, Yamazaki J, Saito M, Yada T, Tominaga M, Iwasaki Y. Involvement of thermosensitive TRP channels in energy metabolism. J Physiol Sci 2017; 67:549-560. [PMID: 28656459 PMCID: PMC10717017 DOI: 10.1007/s12576-017-0552-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/12/2017] [Indexed: 12/22/2022]
Abstract
To date, 11 thermosensitive transient receptor potential (thermo-TRP) channels have been identified. Recent studies have characterized the mechanism of thermosensing by thermo-TRPs and the physiological role of thermo-TRPs in energy metabolism. In this review, we highlight the role of various thermo-TRPs in energy metabolism and hormone secretion. In the pancreas, TRPM2 and other TRPs regulate insulin secretion. TRPV2 expressed in brown adipocytes contributes to differentiation and/or thermogenesis. Sensory nerves that express TRPV1 promote increased energy expenditure by activating sympathetic nerves and adrenaline secretion. Here, we first show that capsaicin-induced adrenaline secretion is completely impaired in TRPV1 knockout mice. The thermogenic effects of TRPV1 agonists are attributable to brown adipose tissue (BAT) activation in mice and humans. Moreover, TRPA1- and TRPM8-expressing sensory nerves also contribute to potentiation of BAT thermogenesis and energy expenditure in mice. Together, thermo-TRPs are promising targets for combating obesity and metabolic disorders.
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Affiliation(s)
- Kunitoshi Uchida
- Division of Cell Signaling, Okazaki Institute for Integrative Biosciences (National Institute for Physiological Sciences), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan.
- Department of Physiological Sciences, SOKENDAI (The University of Advanced Studies), 38 Nishigounaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan.
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, Fukuoka, 814-0193, Japan.
| | - Katsuya Dezaki
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan
| | - Takeshi Yoneshiro
- Diabetes Center, University of California, San Francisco, 35 Medical Center Way, San Francisco, CA, 94143-0669, USA
| | - Tatsuo Watanabe
- Faculty of Future Industry, Happy Science University, 4427-1 Hitotsumatsu-hei, Chosei-mura, Chiba, 299-4325, Japan
| | - Jun Yamazaki
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka, Fukuoka, 814-0193, Japan
| | - Masayuki Saito
- Hokkaido University, Kita18-Nishi9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, Okazaki Institute for Integrative Biosciences (National Institute for Physiological Sciences), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
- Department of Physiological Sciences, SOKENDAI (The University of Advanced Studies), 38 Nishigounaka, Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Yusaku Iwasaki
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan.
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21
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Ito K, Ookawara S, Morishita Y. Hypoglycemic Emergency in Patients With Diabetic Kidney Disease. Ther Apher Dial 2017; 21:512-513. [PMID: 28714255 DOI: 10.1111/1744-9987.12569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 04/22/2017] [Accepted: 04/25/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Kiyonori Ito
- Division of Nephrology, First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Susumu Ookawara
- Division of Nephrology, First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Yoshiyuki Morishita
- Division of Nephrology, First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, Saitama, Japan
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