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Delgado-Ramírez M, López-Serrano AL, Rodríguez-Menchaca AA. Inhibition of Kv2.1 potassium channels by the antidepressant drug sertraline. Eur J Pharmacol 2024; 970:176487. [PMID: 38458411 DOI: 10.1016/j.ejphar.2024.176487] [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: 12/15/2023] [Revised: 02/07/2024] [Accepted: 03/05/2024] [Indexed: 03/10/2024]
Abstract
Sertraline is a commonly used antidepressant of the selective serotonin reuptake inhibitors (SSRIs) class. In this study, we have used the patch-clamp technique to assess the effects of sertraline on Kv2.1 channels heterologously expressed in HEK-293 cells and on the voltage-gated potassium currents (IKv) of Neuro 2a cells, which are predominantly mediated by Kv2.1 channels. Our results reveal that sertraline inhibits Kv2.1 channels in a concentration-dependent manner. The sertraline-induced inhibition was not voltage-dependent and did not require the channels to be open. The kinetics of activation and deactivation were accelerated and decelerated, respectively, by sertraline. Moreover, the inhibition by this drug was use-dependent. Notably, sertraline significantly modified the inactivation mechanism of Kv2.1 channels; the steady-state inactivation was shifted to hyperpolarized potentials, the closed-state inactivation was enhanced and accelerated, and the recovery from inactivation was slowed, suggesting that this is the main mechanism by which sertraline inhibits Kv2.1 channels. Overall, this study provides novel insights into the pharmacological actions of sertraline on Kv2.1 channels, shedding light on the intricate interaction between SSRIs and ion channel function.
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Affiliation(s)
- Mayra Delgado-Ramírez
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, 78210, Mexico.
| | - Ana Laura López-Serrano
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, 78210, Mexico
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, 78210, Mexico
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2
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Lu J, Zhao RX, Xiong FR, Zhu JJ, Shi TT, Zhang YC, Peng GX, Yang JK. All-potassium channel CRISPR screening reveals a lysine-specific pathway of insulin secretion. Mol Metab 2024; 80:101885. [PMID: 38246588 PMCID: PMC10847698 DOI: 10.1016/j.molmet.2024.101885] [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: 12/14/2023] [Revised: 01/04/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
OBJECTIVE Genome-scale CRISPR-Cas9 knockout coupled with single-cell RNA sequencing (scRNA-seq) has been used to identify function-related genes. However, this method may knock out too many genes, leading to low efficiency in finding genes of interest. Insulin secretion is controlled by several electrophysiological events, including fluxes of KATP depolarization and K+ repolarization. It is well known that glucose stimulates insulin secretion from pancreatic β-cells, mainly via the KATP depolarization channel, but whether other nutrients directly regulate the repolarization K+ channel to promote insulin secretion is unknown. METHODS We used a system involving CRISPR-Cas9-mediated knockout of all 83 K+ channels and scRNA-seq in a pancreatic β cell line to identify genes associated with insulin secretion. RESULTS The expression levels of insulin genes were significantly increased after all-K+ channel knockout. Furthermore, Kcnb1 and Kcnh6 were the two most important repolarization K+ channels for the increase in high-glucose-dependent insulin secretion that occurred upon application of specific inhibitors of the channels. Kcnh6 currents, but not Kcnb1 currents, were reduced by one of the amino acids, lysine, in both transfected cells, primary cells and mice with β-cell-specific deletion of Kcnh6. CONCLUSIONS Our function-related CRISPR screen with scRNA-seq identifies Kcnh6 as a lysine-specific channel.
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Affiliation(s)
- Jing Lu
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China
| | - Ru-Xuan Zhao
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China
| | - Feng-Ran Xiong
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China
| | - Juan-Juan Zhu
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China
| | - Ting-Ting Shi
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China
| | - Ying-Chao Zhang
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China
| | - Gong-Xin Peng
- Center for Bioinformatics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100740, China
| | - Jin-Kui Yang
- Department of Endocrinology, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China; Laboratory for Clinical Medicine, Capital Medical University, Beijing 100069, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China.
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3
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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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4
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Coulter-Parkhill A, Gault VA, McClean S, Irwin N. Peptides originally derived from Chilobrachys jingzhao tarantula venom possess beneficial effects on pancreatic beta cell health and function. Eur J Pharmacol 2023:175855. [PMID: 37391009 DOI: 10.1016/j.ejphar.2023.175855] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 07/02/2023]
Abstract
Clinical approval of the glucagon-like peptide-1 (GLP-1) mimetic exenatide for the treatment of type 2 diabetes highlights the therapeutic effectiveness of venom-derived peptides. In the present study, we examined and characterised the glucose-lowering potential of synthetic Jingzhaotoxin IX and Jingzhaotoxin XI peptides, which were originally isolated from the venom of the Chinese earth tarantula Chilobrachys jingzhao. Following confirmation of lack of beta-cell toxicity of synthetic peptides, assessment of enzymatic stability and effects on in vitro beta-cell function were studied, alongside putative mechanisms. Glucose homeostatic and appetite suppressive actions of Jingzhaotoxin IX and Jingzhaotoxin XI alone, or in combination with exenatide, were then assessed in normal overnight fasted C57BL/6 mice. Synthetic Jingzhaotoxin peptides were non-toxic and exhibited a decrease in mass of 6 Da in Krebs-Ringer bicarbonate buffer suggesting inhibitor cysteine knot (ICK)-like formation, but interestingly were liable to plasma enzyme degradation. The Jingzhaotoxin peptides evoked prominent insulin secretion from BRIN BD11 beta-cells, with activity somewhat characteristic of Kv2.1 channel binding. In addition, Jingzhaotoxin peptides enhanced beta-cell proliferation and provided significant protection against cytokine-induced apoptosis. When injected co-jointly with glucose, the Jingzhaotoxin peptides slightly decreased blood-glucose levels but had no effect on appetite in overnight fasted mice. Whilst the Jingzhaotoxin peptides did not enhance exenatide-induced benefits on glucose homeostasis, they augmented exenatide-mediated suppression of appetite. Taken together, these data highlight the therapeutic potential of tarantula venom-derived peptides, such as Jingzhaotoxin IX and Jingzhaotoxin XI either alone or in combination with exenatide, for diabetes and related obesity.
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Affiliation(s)
- A Coulter-Parkhill
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, UK
| | - V A Gault
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, UK
| | - S McClean
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, UK
| | - N Irwin
- Diabetes Research Centre, Ulster University, Coleraine, Northern Ireland, UK.
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Lodato M, Plaisance V, Pawlowski V, Kwapich M, Barras A, Buissart E, Dalle S, Szunerits S, Vicogne J, Boukherroub R, Abderrahmani A. Venom Peptides, Polyphenols and Alkaloids: Are They the Next Antidiabetics That Will Preserve β-Cell Mass and Function in Type 2 Diabetes? Cells 2023; 12:cells12060940. [PMID: 36980281 PMCID: PMC10047094 DOI: 10.3390/cells12060940] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/09/2023] [Accepted: 03/17/2023] [Indexed: 03/22/2023] Open
Abstract
Improvement of insulin secretion by pancreatic β-cells and preservation of their mass are the current challenges that future antidiabetic drugs should meet for achieving efficient and long-term glycemic control in patients with type 2 diabetes (T2D). The successful development of glucagon-like peptide 1 (GLP-1) analogues, derived from the saliva of a lizard from the Helodermatidae family, has provided the proof of concept that antidiabetic drugs directly targeting pancreatic β-cells can emerge from venomous animals. The literature reporting on the antidiabetic effects of medicinal plants suggests that they contain some promising active substances such as polyphenols and alkaloids, which could be active as insulin secretagogues and β-cell protectors. In this review, we discuss the potential of several polyphenols, alkaloids and venom peptides from snake, frogs, scorpions and cone snails. These molecules could contribute to the development of new efficient antidiabetic medicines targeting β-cells, which would tackle the progression of the disease.
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Affiliation(s)
- Michele Lodato
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Valérie Plaisance
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Valérie Pawlowski
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Maxime Kwapich
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
- Service de Diabétologie et d’Endocrinologie, CH Dunkerque, 59385 Dunkirk, France
| | - Alexandre Barras
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Emeline Buissart
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Stéphane Dalle
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Sabine Szunerits
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Jérôme Vicogne
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Rabah Boukherroub
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Amar Abderrahmani
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
- Correspondence: ; Tel.: +33-362531704
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Zhao X, Deng L, Ren L, Yang H, Wang B, Zhu X, Zhang X, Guo C, Zhang Y, Liu Y. VPAC2 receptor mediates VIP-potentiated insulin secretion via ion channels in rat pancreatic β cells. Exp Cell Res 2023; 423:113471. [PMID: 36642263 DOI: 10.1016/j.yexcr.2023.113471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/04/2023] [Accepted: 01/06/2023] [Indexed: 01/15/2023]
Abstract
Vasoactive intestinal peptide (VIP), a small neuropeptide composing of 28 amino acids, functions as a neuromodulator with insulinotropic effect on pancreatic β cells, in which it is of vital importance in regulating the levels of blood glucose. VIP potently agonizes VPAC2 receptor (VPAC2-R). Agonists of VPAC2-R stimulate glucose-dependent insulin secretion. The purpose of this study was to further investigate the possible ion channel mechanisms in VPAC2-R-mediated VIP-potentiated insulin secretion. The results of insulin secretion experiments showed that VIP augmented insulin secretion in a glucose-dependent manner. The insulinotropic effect was mediated by VPAC2-R rather than VPAC1 receptor (VPAC1-R), through the adenylyl cyclase (AC)/protein kinase A (PKA) signalling pathway. The calcium imaging analysis demonstrated that VIP increased intracellular Ca2+ concentration ([Ca2+]i). In addition, in the whole-cell voltage-clamp mode, we found that VIP blocked the voltage-dependent potassium (Kv) channel currents, while this effect was reversed by inhibiting the VPAC2-R, AC or PKA respectively. Taken together, these findings suggest that VIP stimulates insulin secretion by inhibiting the Kv channels, activating the Ca2+ channels, and increasing [Ca2+]i through the VPAC2-R and AC/PKA signalling pathway. These findings provide theoretical basis for the research of VPAC2-R as a novel therapeutic target.
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Affiliation(s)
- Xin Zhao
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Lijiao Deng
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Lele Ren
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Huanhuan Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Bin Wang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Xiaochan Zhu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Xiaoli Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Chao Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
| | - Yunfeng Liu
- Department of Endocrinology, First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, 030001, Shanxi, China.
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7
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Purwaningsih I, Maksum IP, Sumiarsa D, Sriwidodo S. A Review of Fibraurea tinctoria and Its Component, Berberine, as an Antidiabetic and Antioxidant. Molecules 2023; 28:molecules28031294. [PMID: 36770960 PMCID: PMC9919506 DOI: 10.3390/molecules28031294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Diabetes mellitus is a group of metabolic disorders characterized by hyperglycemia caused by resistance to insulin action, inadequate insulin secretion, or excessive glucagon production. Numerous studies have linked diabetes mellitus and oxidative stress. People with diabetes usually exhibit high oxidative stress due to persistent and chronic hyperglycemia, which impairs the activity of the antioxidant defense system and promotes the formation of free radicals. Recently, several studies have focused on exploring natural antioxidants to improve diabetes mellitus. Fibraurea tinctoria has long been known as the native Borneo used in traditional medicine to treat diabetes. Taxonomically, this plant is part of the Menispermaceae family, widely known for producing various alkaloids. Among them are protoberberine alkaloids such as berberine. Berberine is an isoquinoline alkaloid with many pharmacological activities. Berberine is receiving considerable interest because of its antidiabetic and antioxidant activities, which are based on many biochemical pathways. Therefore, this review explores the pharmacological effects of Fibraurea tinctoria and its active constituent, berberine, against oxidative stress and diabetes, emphasizing its mechanistic aspects. This review also summarizes the pharmacokinetics and toxicity of berberine and in silico studies of berberine in several diseases and its protein targets.
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Affiliation(s)
- Indah Purwaningsih
- Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Padjadjaran, Sumedang 45363, Indonesia
- Department of Medical Laboratory Technology, Poltekkes Kemenkes Pontianak, Pontianak 78124, Indonesia
- Correspondence: (I.P.); (I.P.M.)
| | - Iman Permana Maksum
- Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Padjadjaran, Sumedang 45363, Indonesia
- Correspondence: (I.P.); (I.P.M.)
| | - Dadan Sumiarsa
- Department of Chemistry, Faculty of Mathematics and Natural Science, Universitas Padjadjaran, Sumedang 45363, Indonesia
| | - Sriwidodo Sriwidodo
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Universitas Padjadjaran, Sumedang 45363, Indonesia
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Lubberding AF, Juhl CR, Skovhøj EZ, Kanters JK, Mandrup‐Poulsen T, Torekov SS. Celebrities in the heart, strangers in the pancreatic beta cell: Voltage-gated potassium channels K v 7.1 and K v 11.1 bridge long QT syndrome with hyperinsulinaemia as well as type 2 diabetes. Acta Physiol (Oxf) 2022; 234:e13781. [PMID: 34990074 PMCID: PMC9286829 DOI: 10.1111/apha.13781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/20/2021] [Accepted: 01/02/2022] [Indexed: 12/13/2022]
Abstract
Voltage‐gated potassium (Kv) channels play an important role in the repolarization of a variety of excitable tissues, including in the cardiomyocyte and the pancreatic beta cell. Recently, individuals carrying loss‐of‐function (LoF) mutations in KCNQ1, encoding Kv7.1, and KCNH2 (hERG), encoding Kv11.1, were found to exhibit post‐prandial hyperinsulinaemia and episodes of hypoglycaemia. These LoF mutations also cause the cardiac disorder long QT syndrome (LQTS), which can be aggravated by hypoglycaemia. Interestingly, patients with LQTS also have a higher burden of diabetes compared to the background population, an apparent paradox in relation to the hyperinsulinaemic phenotype, and KCNQ1 has been identified as a type 2 diabetes risk gene. This review article summarizes the involvement of delayed rectifier K+ channels in pancreatic beta cell function, with emphasis on Kv7.1 and Kv11.1, using the cardiomyocyte for context. The functional and clinical consequences of LoF mutations and polymorphisms in these channels on blood glucose homeostasis are explored using evidence from pre‐clinical, clinical and genome‐wide association studies, thereby evaluating the link between LQTS, hyperinsulinaemia and type 2 diabetes.
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Affiliation(s)
- Anniek F. Lubberding
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Christian R. Juhl
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Emil Z. Skovhøj
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Jørgen K. Kanters
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Thomas Mandrup‐Poulsen
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Signe S. Torekov
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
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Thompson B, Satin LS. Beta-Cell Ion Channels and Their Role in Regulating Insulin Secretion. Compr Physiol 2021; 11:1-21. [PMID: 34636409 PMCID: PMC8935893 DOI: 10.1002/cphy.c210004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Beta cells of the pancreatic islet express many different types of ion channels. These channels reside in the β-cell plasma membrane as well as subcellular organelles and their coordinated activity and sensitivity to metabolism regulate glucose-dependent insulin secretion. Here, we review the molecular nature, expression patterns, and functional roles of many β-cell channels, with an eye toward explaining the ionic basis of glucose-induced insulin secretion. Our primary focus is on KATP and voltage-gated Ca2+ channels as these primarily regulate insulin secretion; other channels in our view primarily help to sculpt the electrical patterns generated by activated β-cells or indirectly regulate metabolism. Lastly, we discuss why understanding the physiological roles played by ion channels is important for understanding the secretory defects that occur in type 2 diabetes. © 2021 American Physiological Society. Compr Physiol 11:1-21, 2021.
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Zhao MM, Lu J, Li S, Wang H, Cao X, Li Q, Shi TT, Matsunaga K, Chen C, Huang H, Izumi T, Yang JK. Berberine is an insulin secretagogue targeting the KCNH6 potassium channel. Nat Commun 2021; 12:5616. [PMID: 34556670 PMCID: PMC8460738 DOI: 10.1038/s41467-021-25952-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 09/08/2021] [Indexed: 11/09/2022] Open
Abstract
Coptis chinensis is an ancient Chinese herb treating diabetes in China for thousands of years. However, its underlying mechanism remains poorly understood. Here, we report the effects of its main active component, berberine (BBR), on stimulating insulin secretion. In mice with hyperglycemia induced by a high-fat diet, BBR significantly increases insulin secretion and reduced blood glucose levels. However, in mice with hyperglycemia induced by global or pancreatic islet β-cell-specific Kcnh6 knockout, BBR does not exert beneficial effects. BBR directly binds KCNH6 potassium channels, significantly accelerates channel closure, and subsequently reduces KCNH6 currents. Consequently, blocking KCNH6 currents prolongs high glucose-dependent cell membrane depolarization and increases insulin secretion. Finally, to assess the effect of BBR on insulin secretion in humans, a randomized, double-blind, placebo-controlled, two-period crossover, single-dose, phase 1 clinical trial (NCT03972215) including 15 healthy men receiving a 160-min hyperglycemic clamp experiment is performed. The pre-specified primary outcomes are assessment of the differences of serum insulin and C-peptide levels between BBR and placebo treatment groups during the hyperglycemic clamp study. BBR significantly promotes insulin secretion under hyperglycemic state comparing with placebo treatment, while does not affect basal insulin secretion in humans. All subjects tolerate BBR well, and we observe no side effects in the 14-day follow up period. In this study, we identify BBR as a glucose-dependent insulin secretagogue for treating diabetes without causing hypoglycemia that targets KCNH6 channels.
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Affiliation(s)
- Miao-Miao Zhao
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
| | - Jing Lu
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
| | - Sen Li
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
| | - Hao Wang
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Xi Cao
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
| | - Qi Li
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
| | - Ting-Ting Shi
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China
| | - Kohichi Matsunaga
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Haixia Huang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, 100069, Beijing, China
| | - Tetsuro Izumi
- Laboratory of Molecular Endocrinology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Jin-Kui Yang
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, 100730, Beijing, China.
- Beijing Key Laboratory of Diabetes Research and Care, Beijing Diabetes Institute, 100730, Beijing, China.
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Liu Z, Yang H, Zhi L, Xue H, Lu Z, Zhao Y, Cui L, Liu T, Ren S, He P, Liu Y, Zhang Y. Sphingosine 1-phosphate Stimulates Insulin Secretion and Improves Cell Survival by Blocking Voltage-dependent K + Channels in β Cells. Front Pharmacol 2021; 12:683674. [PMID: 34322019 PMCID: PMC8313013 DOI: 10.3389/fphar.2021.683674] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/29/2021] [Indexed: 12/25/2022] Open
Abstract
Recent studies suggest that Sphingosine 1-phosphate (S1P) plays an important role in regulating glucose metabolism in type 2 diabetes. However, its effects and mechanisms of promoting insulin secretion remain largely unknown. Here, we found that S1P treatment decreased blood glucose level and increased insulin secretion in C57BL/6 mice. Our results further showed that S1P promoted insulin secretion in a glucose-dependent manner. This stimulatory effect of S1P appeared to be irrelevant to cyclic adenosine monophosphate signaling. Voltage-clamp recordings showed that S1P did not influence voltage-dependent Ca2+ channels, but significantly blocked voltage-dependent potassium (Kv) channels, which could be reversed by inhibition of phospholipase C (PLC) and protein kinase C (PKC). Calcium imaging revealed that S1P increased intracellular Ca2+ levels, mainly by promoting Ca2+ influx, rather than mobilizing intracellular Ca2+ stores. In addition, inhibition of PLC and PKC suppressed S1P-induced insulin secretion. Collectively, these results suggest that the effects of S1P on glucose-stimulated insulin secretion (GSIS) depend on the inhibition of Kv channels via the PLC/PKC signaling pathway in pancreatic β cells. Further, S1P improved β cell survival; this effect was also associated with Kv channel inhibition. This work thus provides new insights into the mechanisms whereby S1P regulates β cell function in diabetes.
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Affiliation(s)
- Zhihong Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.,Department of Respiratory and Critical Care Medicine, First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Huanhuan Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Linping Zhi
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Huan Xue
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Zhihong Lu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yanli Zhao
- Department of Emergency Medicine, First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Lijuan Cui
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Tao Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Shouan Ren
- Department of Respiratory and Critical Care Medicine, First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Peifeng He
- School of Management, Shanxi Medical University, Taiyuan, China
| | - Yunfeng Liu
- Department of Endocrinology, First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.,Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
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12
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Coulter-Parkhill A, McClean S, Gault VA, Irwin N. Therapeutic Potential of Peptides Derived from Animal Venoms: Current Views and Emerging Drugs for Diabetes. Clin Med Insights Endocrinol Diabetes 2021; 14:11795514211006071. [PMID: 34621137 PMCID: PMC8491154 DOI: 10.1177/11795514211006071] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/10/2021] [Indexed: 12/13/2022] Open
Abstract
The therapeutic potential of venom-derived drugs is evident today. Currently, several significant drugs are FDA approved for human use that descend directly from animal venom products, with others having undergone, or progressing through, clinical trials. In addition, there is growing awareness of the important cosmeceutical application of venom-derived products. The success of venom-derived compounds is linked to their increased bioactivity, specificity and stability when compared to synthetically engineered compounds. This review highlights advancements in venom-derived compounds for the treatment of diabetes and related disorders. Exendin-4, originating from the saliva of Gila monster lizard, represents proof-of-concept for this drug discovery pathway in diabetes. More recent evidence emphasises the potential of venom-derived compounds from bees, cone snails, sea anemones, scorpions, snakes and spiders to effectively manage glycaemic control. Such compounds could represent exciting exploitable scaffolds for future drug discovery in diabetes, as well as providing tools to allow for a better understanding of cell signalling pathways linked to insulin secretion and metabolism.
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Affiliation(s)
| | | | - Victor A Gault
- Diabetes Research Group, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Group, Ulster University, Coleraine, UK
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13
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Antispasmodic Drug Drofenine as an Inhibitor of Kv2.1 Channel Ameliorates Peripheral Neuropathy in Diabetic Mice. iScience 2020; 23:101617. [PMID: 33089105 PMCID: PMC7559245 DOI: 10.1016/j.isci.2020.101617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 07/22/2020] [Accepted: 09/23/2020] [Indexed: 12/30/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a common diabetic complication and has yet no efficient medication. Here, we report that antispasmodic drug drofenine (Dfe) blocks Kv2.1 and ameliorates DPN-like pathology in diabetic mice. The underlying mechanisms are investigated against the DPN mice with in vivo Kv2.1 knockdown through adeno associated virus AAV9-Kv2.1-RNAi. Streptozotocin (STZ) induced type 1 or db/db type 2 diabetic mice with DPN exhibited a high level of Kv2.1 protein in dorsal root ganglion (DRG) tissue and a suppressed neurite outgrowth in DRG neuron. Dfe promoted neurite outgrowth by inhibiting Kv2.1 channel and/or Kv2.1 mRNA and protein expression level. Moreover, it suppressed inflammation by repressing IκBα/NF-κB signaling, inhibited apoptosis by regulating Kv2.1-mediated Bcl-2 family proteins and Caspase-3 and ameliorated mitochondrial dysfunction through Kv2.1/CaMKKβ/AMPK/PGC1α pathway. Our work supports that Kv2.1 inhibition is a promisingly therapeutic strategy for DPN and highlights the potential of Dfe in treating this disease. Antispasmodic drug drofenine (Dfe) ameliorates DPN-like pathology in diabetic mice Dfe inhibits Kv2.1 channel and/or Kv2.1 mRNA and protein expression level Dfe represses inflammation, apoptosis, and mitochondrial dysfunction in DPN mice Kv2.1 inhibition is a therapeutic tactic and Dfe shows therapeutic potential for DPN
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14
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CDK8 Regulates Insulin Secretion and Mediates Postnatal and Stress-Induced Expression of Neuropeptides in Pancreatic β Cells. Cell Rep 2020; 28:2892-2904.e7. [PMID: 31509750 DOI: 10.1016/j.celrep.2019.08.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/26/2019] [Accepted: 08/05/2019] [Indexed: 12/13/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) contribute to vital cellular processes including cell cycle regulation. Loss of CDKs is associated with impaired insulin secretion and β cell survival; however, the function of CDK8 in β cells remains elusive. Here, we report that genetic ablation of Cdk8 improves glucose tolerance by increasing insulin secretion. We identify OSBPL3 as a CDK8-dependent phosphoprotein, which acts as a negative regulator of insulin secretion in response to glucose. We also show that embryonic gene silencing of neuropeptide Y in β cells is compromised in Cdk8-null mice, leading to continued expression into adulthood. Cdk8 ablation in β cells aggravates apoptosis and induces de novo expression of neuropeptides upon oxidative stress. Moreover, pancreatic islets exposed to stress display augmented apoptosis in the presence of these same neuropeptides. Our results reveal critical roles for CDK8 in β cell function and survival during metabolic stress that are in part mediated through de novo expression of neuropeptides.
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15
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Liu M, Ren L, Zhong X, Ding Y, Liu T, Liu Z, Yang X, Cui L, Yang L, Fan Y, Liu Y, Zhang Y. D2-Like Receptors Mediate Dopamine-Inhibited Insulin Secretion via Ion Channels in Rat Pancreatic β-Cells. Front Endocrinol (Lausanne) 2020; 11:152. [PMID: 32318020 PMCID: PMC7154177 DOI: 10.3389/fendo.2020.00152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 03/04/2020] [Indexed: 11/25/2022] Open
Abstract
Dopamine (DA) has a vital role in the central nervous system and also modulates lipid and glucose metabolism. The present study aimed to investigate the effect of dopamine on insulin secretion and the underlying mechanisms in rat pancreatic β-cells. Data from the radioimmunoassay indicated that dopamine inhibited insulin secretion in a glucose- and dose-dependent manner. This inhibitory effect of dopamine was mediated mainly by D2-like receptors, but not D1-like receptors. Whole-cell patch-clamp recordings showed that dopamine decreased voltage-dependent Ca2+ channel currents, which could be reversed by inhibition of the D2-like receptor. Dopamine increased voltage-dependent potassium (KV) channel currents and shortened action potential duration, which was antagonized by inhibition of D2-like receptors. Further experiments showed that D2-like receptor activation by quinpirole increased KV channel currents. In addition, using calcium imaging techniques, we found that dopamine reduced intracellular Ca2+ concentration, which was also reversed by D2-like receptor antagonists. Similarly, quinpirole was found to decrease intracellular Ca2+ levels. Taken together, these findings demonstrate that dopamine inhibits insulin secretion mainly by acting on D2-like receptors, inhibiting Ca2+ channels, and activating Kv channels. This process results in shortened action potential duration and decreased intracellular Ca2+ levels in β-cells. This work offers new insights into a glucose-dependent mechanism whereby dopamine regulates insulin secretion.
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Affiliation(s)
- Mengmeng Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Lele Ren
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Xiangqin Zhong
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yaqin Ding
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Tao Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Zhihong Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Xiaohua Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Lijuan Cui
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Lijun Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yanying Fan
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yunfeng Liu
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
- *Correspondence: Yunfeng Liu
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
- Yi Zhang
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16
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Bai T, Yang H, Wang H, Zhi L, Liu T, Cui L, Liu W, Wang Y, Zhang M, Liu Y, Zhang Y. Inhibition of voltage-gated K+ channels mediates docosahexaenoic acid-stimulated insulin secretion in rat pancreatic β-cells. Food Funct 2020; 11:8893-8904. [DOI: 10.1039/d0fo01891k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Kv channels play a vital role in DHA-augmented insulin secretion through GPR40/AC/cAMP/PLC signaling pathway in rat pancreatic β-cells.
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17
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Pharmacological polysulfide suppresses glucose-stimulated insulin secretion in an ATP-sensitive potassium channel-dependent manner. Sci Rep 2019; 9:19377. [PMID: 31852936 PMCID: PMC6920347 DOI: 10.1038/s41598-019-55848-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 12/03/2019] [Indexed: 12/17/2022] Open
Abstract
Hydrogen sulfide (H2S) is an endogenous gaseous transmitter synthesized in various cell types. It is well established that H2S functions in many physiological processes, including the relaxation of vascular smooth muscle, mediation of neurotransmission, regulation of inflammation, and modulation of insulin signaling. In recent years, it has been revealed that polysulfides, substances with a varying number of sulfur atoms (H2Sn), are generated endogenously from H2S in the presence of oxygen. A series of studies describes that sulfane sulfur has the unique ability to bind reversibly to other sulfur atoms to form hydropersulfides and polysulfides, and that polysulfides activate ion channels and promote calcium influx. Furthermore, polysulfides regulate tumor suppressor activity, promote the activation of transcription factors targeting antioxidant genes and regulate blood pressure by vascular smooth muscle relaxation. Insulin secretion from pancreatic β cells plays a critical role in response to increased blood glucose concentration. H2S has emerged as an important regulator of glycemic control and exhibits characteristic regulation of glucose homeostasis. However, the effects of polysulfides on glucose-stimulated insulin secretion (GSIS) are largely unknown. In this study, we demonstrated that pharmacological polysulfide salts including Na2S2, Na2S3, and Na2S4 considerably inhibit GSIS in mouse and rat pancreatic β-cell-derived MIN6 and INS-1 cell lines, and that the effect is dependent on the activation of ATP-sensitive potassium channels. In addition, we demonstrated that a mixture of Na2S and diethylamine NONOate inhibits GSIS in a similar way to the pharmacological administration of polysulfide salts.
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18
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From Hyper- to Hypoinsulinemia and Diabetes: Effect of KCNH6 on Insulin Secretion. Cell Rep 2019; 25:3800-3810.e6. [PMID: 30590050 DOI: 10.1016/j.celrep.2018.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/26/2018] [Accepted: 11/30/2018] [Indexed: 01/03/2023] Open
Abstract
Glucose-stimulated insulin secretion from islet β cells is mediated by KATP channels. However, the role of non-KATP K+ channels in insulin secretion is largely unknown. Here, we show that a non-KATP K+ channel, KCNH6, plays a key role in insulin secretion and glucose hemostasis in humans and mice. KCNH6 p.P235L heterozygous mutation co-separated with diabetes in a four-generation pedigree. Kcnh6 knockout (KO) or Kcnh6 p.P235L knockin (KI) mice had a phenotype characterized by changing from hypoglycemia with hyperinsulinemia to hyperglycemia with insulin deficiency. Islets from the young KO mice had increased intracellular calcium concentration and increased insulin secretion. However, islets from the adult KO mice not only had increased intracellular calcium levels but also had remarkable ER stress and apoptosis, associated with loss of β cell mass and decreased insulin secretion. Therefore, dysfunction of KCNH6 causes overstimulation of insulin secretion in the short term and β cell failure in the long term.
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19
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Kusunoki M, Hayashi M, Shoji T, Uba T, Tanaka H, Sumi C, Matsuo Y, Hirota K. Propofol inhibits stromatoxin-1-sensitive voltage-dependent K + channels in pancreatic β-cells and enhances insulin secretion. PeerJ 2019; 7:e8157. [PMID: 31824770 PMCID: PMC6894434 DOI: 10.7717/peerj.8157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/04/2019] [Indexed: 12/31/2022] Open
Abstract
Background Proper glycemic control is an important goal of critical care medicine, including perioperative patient care that can influence patients’ prognosis. Insulin secretion from pancreatic β-cells is generally assumed to play a critical role in glycemic control in response to an elevated blood glucose concentration. Many animal and human studies have demonstrated that perioperative drugs, including volatile anesthetics, have an impact on glucose-stimulated insulin secretion (GSIS). However, the effects of the intravenous anesthetic propofol on glucose metabolism and insulin sensitivity are largely unknown at present. Methods The effect of propofol on insulin secretion under low glucose or high glucose was examined in mouse MIN6 cells, rat INS-1 cells, and mouse pancreatic β-cells/islets. Cellular oxygen or energy metabolism was measured by Extracellular Flux Analyzer. Expression of glucose transporter 2 (GLUT2), potassium channels, and insulin mRNA was assessed by qRT-PCR. Protein expression of voltage-dependent potassium channels (Kv2) was also assessed by immunoblot. Propofol’s effects on potassium channels including stromatoxin-1-sensitive Kv channels and cellular oxygen and energy metabolisms were also examined. Results We showed that propofol, at clinically relevant doses, facilitates insulin secretion under low glucose conditions and GSIS in MIN6, INS-1 cells, and pancreatic β-cells/islets. Propofol did not affect intracellular ATP or ADP concentrations and cellular oxygen or energy metabolism. The mRNA expression of GLUT2 and channels including the voltage-dependent calcium channels Cav1.2, Kir6.2, and SUR1 subunit of KATP, and Kv2 were not affected by glucose or propofol. Finally, we demonstrated that propofol specifically blocks Kv currents in β-cells, resulting in insulin secretion in the presence of glucose. Conclusions Our data support the hypothesis that glucose induces membrane depolarization at the distal site, leading to KATP channel closure, and that the closure of Kv channels by propofol depolarization in β-cells enhances Ca2+ entry, leading to insulin secretion. Because its activity is dependent on GSIS, propofol and its derivatives are potential compounds that enhance and initiate β-cell electrical activity.
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Affiliation(s)
- Munenori Kusunoki
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Mikio Hayashi
- Department of Cell Physiology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Tomohiro Shoji
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Takeo Uba
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Hiromasa Tanaka
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Chisato Sumi
- Department of Anesthesiology, Kansai Medical University, Hirakata, Japan.,Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Yoshiyuki Matsuo
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Kiichi Hirota
- Department of Human Stress Response Science, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
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20
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Martinez-Pinna J, Marroqui L, Hmadcha A, Lopez-Beas J, Soriano S, Villar-Pazos S, Alonso-Magdalena P, Dos Santos RS, Quesada I, Martin F, Soria B, Gustafsson JÅ, Nadal A. Oestrogen receptor β mediates the actions of bisphenol-A on ion channel expression in mouse pancreatic beta cells. Diabetologia 2019; 62:1667-1680. [PMID: 31250031 DOI: 10.1007/s00125-019-4925-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/26/2019] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Bisphenol-A (BPA) is a widespread endocrine-disrupting chemical that has been associated with type 2 diabetes development. Low doses of BPA modify pancreatic beta cell function and induce insulin resistance; some of these effects are mediated via activation of oestrogen receptors α (ERα) and β (ERβ). Here we investigated whether low doses of BPA regulate the expression and function of ion channel subunits involved in beta cell function. METHODS Microarray gene profiling of isolated islets from vehicle- and BPA-treated (100 μg/kg per day for 4 days) mice was performed using Affymetrix GeneChip Mouse Genome 430.2 Array. Expression level analysis was performed using the normalisation method based on the processing algorithm 'robust multi-array average'. Whole islets or dispersed islets from C57BL/6J or oestrogen receptor β (ERβ) knockout (Erβ-/-) mice were treated with vehicle or BPA (1 nmol/l) for 48 h. Whole-cell patch-clamp recordings were used to measure Na+ and K+ currents. mRNA expression was evaluated by quantitative real-time PCR. RESULTS Microarray analysis showed that BPA modulated the expression of 1440 probe sets (1192 upregulated and 248 downregulated genes). Of these, more than 50 genes, including Scn9a, Kcnb2, Kcnma1 and Kcnip1, encoded important Na+ and K+ channel subunits. These findings were confirmed by quantitative RT-PCR in islets from C57BL/6J BPA-treated mice or whole islets treated ex vivo. Electrophysiological measurements showed a decrease in both Na+ and K+ currents in BPA-treated islets. The pharmacological profile indicated that BPA reduced currents mediated by voltage-activated K+ channels (Kv2.1/2.2 channels) and large-conductance Ca2+-activated K+ channels (KCa1.1 channels), which agrees with BPA's effects on gene expression. Beta cells from ERβ-/- mice did not present BPA-induced changes, suggesting that ERβ mediates BPA's effects in pancreatic islets. Finally, BPA increased burst duration, reduced the amplitude of the action potential and enlarged the action potential half-width, leading to alteration in beta cell electrical activity. CONCLUSIONS/INTERPRETATION Our data suggest that BPA modulates the expression and function of Na+ and K+ channels via ERβ in mouse pancreatic islets. Furthermore, BPA alters beta cell electrical activity. Altogether, these BPA-induced changes in beta cells might play a role in the diabetogenic action of BPA described in animal models.
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Affiliation(s)
- Juan Martinez-Pinna
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Laura Marroqui
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Abdelkrim Hmadcha
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Javier Lopez-Beas
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Sergi Soriano
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Sabrina Villar-Pazos
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Paloma Alonso-Magdalena
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Reinaldo S Dos Santos
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Ivan Quesada
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Franz Martin
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Bernat Soria
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Jan-Åke Gustafsson
- Department of Cell Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, USA
- Department of Biosciences and Nutrition, Karolinska Institut, Huddinge, Sweden
| | - Angel Nadal
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain.
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain, .
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21
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PACAP stimulates insulin secretion by PAC1 receptor and ion channels in β-cells. Cell Signal 2019; 61:48-56. [DOI: 10.1016/j.cellsig.2019.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/28/2019] [Accepted: 05/06/2019] [Indexed: 01/02/2023]
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22
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Sarmiento BE, Santos Menezes LF, Schwartz EF. Insulin Release Mechanism Modulated by Toxins Isolated from Animal Venoms: From Basic Research to Drug Development Prospects. Molecules 2019; 24:E1846. [PMID: 31091684 PMCID: PMC6571724 DOI: 10.3390/molecules24101846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/23/2019] [Accepted: 05/09/2019] [Indexed: 12/12/2022] Open
Abstract
Venom from mammals, amphibians, snakes, arachnids, sea anemones and insects provides diverse sources of peptides with different potential medical applications. Several of these peptides have already been converted into drugs and some are still in the clinical phase. Diabetes type 2 is one of the diseases with the highest mortality rate worldwide, requiring specific attention. Diverse drugs are available (e.g., Sulfonylureas) for effective treatment, but with several adverse secondary effects, most of them related to the low specificity of these compounds to the target. In this context, the search for specific and high-affinity compounds for the management of this metabolic disease is growing. Toxins isolated from animal venom have high specificity and affinity for different molecular targets, of which the most important are ion channels. This review will present an overview about the electrical activity of the ion channels present in pancreatic β cells that are involved in the insulin secretion process, in addition to the diversity of peptides that can interact and modulate the electrical activity of pancreatic β cells. The importance of prospecting bioactive peptides for therapeutic use is also reinforced.
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Affiliation(s)
- Beatriz Elena Sarmiento
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
| | - Luis Felipe Santos Menezes
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
| | - Elisabeth F Schwartz
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
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Zhou T, Du M, Zhao T, Quan L, Zhu Z, Chen J. ETA as a novel Kv2.1 inhibitor ameliorates β-cell dysfunction and hyperglycaemia. Clin Exp Pharmacol Physiol 2018; 45:1257-1264. [PMID: 30003581 DOI: 10.1111/1440-1681.13011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/10/2018] [Accepted: 07/10/2018] [Indexed: 12/01/2022]
Abstract
The Kv2.1 channel plays an important role in the regulation against pancreatic β-cell dysfunctions. Therefore, it is regarded as a promising target for drug discovery against type 2 diabetes. In the present study, we found that the small molecule 4-ethoxy-N-{[6-(2-thienyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl]methyl}aniline (ETA), a novel Kv2.1 inhibitor, may be capable of promoting glucose-stimulated insulin secretion and protecting from apoptosis in pancreatic INS-832/13 cells. The assay of ETA on type 2 diabetic mice induced by high-fat diet (HFD)/streptozocin (STZ) confirmed its potency in ameliorating glucose homeostasis. ETA administration reduced fasting blood glucose and glycated haemoglobin levels, improved oral glucose tolerance, and increased serum insulin levels in HFD/STZ mice. Mechanism study demonstrated that ETA protected INS-832/13 cells involving the regulation against protein kinase B and extracellular-regulated protein kinase 1/2 signalling pathways. Our study has confirmed the underlying regulation of Kv2.1 against β-cell function and also addressed the potential of ETA as a lead compound in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Tingting Zhou
- Wuxi School of Medicine, Jiangnan University, Wuxi, China.,Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Mengfan Du
- School of Pharmaceutical Sciences, Jiangnan University, Wuxi, China
| | - Tong Zhao
- State Key Laboratory Cultivation Base for TCM Quality and Efficacy, School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, China
| | - Lingling Quan
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - Zhiyuan Zhu
- Central Laboratory, Suzhou Kowloon Hospital, Shanghai Jiaotong University School of Medicine, Suzhou, China
| | - Jing Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
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24
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Xu Y, Shi W, Song R, Long W, Guo H, Yuan S, Zhang T. Divergent patterns of genic copy number variation in KCNIP1 gene reveal risk locus of type 2 diabetes in Chinese population. Endocr J 2018; 65:537-545. [PMID: 29491224 DOI: 10.1507/endocrj.ej17-0496] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Copy number variation (CNV) has emerged as another important genetic marker in addition to SNP for understanding etiology of complex disease. Kv channel interacting protein 1 (KCNIP1) is a Ca2+-dependent transcriptional modulator that contributes to the regulation of insulin secretion. Previous genome-wide CNV assay identified the KCNIP1 gene encompassing a CNV region, however, its further effect and risk rate on type 2 diabetes (T2D) have rarely been addressed, especially in Chinese population. The current study aims to detect and excavate genetic distribution profile of KCNIP1 CNV in Chinese T2D and control populations, and further to investigate the associations with clinical characteristics. Divergent patterns of the KCNIP1 CNV were identified (p < 0.01), in which the copy number gain was predominant in T2D, while the copy number normal accounted for the most in control group. Consistently, the individuals with copy number gain showed significant risk on T2D (OR = 4.550, p < 0.01). The KCNIP1 copy numbers presented significantly positive correlations with fasting plasma glucose and glycated hemoglobin in T2D. For OGTT test, the T2D patients with copy number gain had remarkably elevated glucose contents (60, 120, 180-min, p < 0.05 or p < 0.01) and diminished insulin levels (60, 120-min, p < 0.05) than those with copy number loss and normal, which suggested that the KCNIP1 CNV was correlated with the glucose and insulin action. This is the first CNV association study of the KCNIP1 gene in Chinese population, and these data indicated that KCNIP1 might function as a T2D-susceptibility gene whose dysregulation alters insulin production.
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Affiliation(s)
- Yao Xu
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China
| | - Weilin Shi
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China
| | - Ruhui Song
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China
| | - Wenlin Long
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China
| | - Hui Guo
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China
| | - Shiliang Yuan
- Tianyou Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, Hubei 430064, China
| | - Tongcun Zhang
- Institute of Biology and Medicine, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China
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25
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Greitzer-Antes D, Xie L, Qin T, Xie H, Zhu D, Dolai S, Liang T, Kang F, Hardy AB, He Y, Kang Y, Gaisano HY. K v2.1 clusters on β-cell plasma membrane act as reservoirs that replenish pools of newcomer insulin granule through their interaction with syntaxin-3. J Biol Chem 2018; 293:6893-6904. [PMID: 29549124 DOI: 10.1074/jbc.ra118.002703] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 03/09/2018] [Indexed: 01/22/2023] Open
Abstract
The voltage-dependent K+ (Kv) channel Kv2.1 is a major delayed rectifier in many secretory cells, including pancreatic β cells. In addition, Kv2.1 has a direct role in exocytosis at an undefined step, involving SNARE proteins, that is independent of its ion-conducting pore function. Here, we elucidated the precise step in exocytosis. We previously reported that syntaxin-3 (Syn-3) is the key syntaxin that mediates exocytosis of newcomer secretory granules that spend minimal residence time on the plasma membrane before fusion. Using high-resolution total internal reflection fluorescence microscopy, we now show that Kv2.1 forms reservoir clusters on the β-cell plasma membrane and binds Syn-3 via its C-terminal C1b domain, which recruits newcomer insulin secretory granules into this large reservoir. Upon glucose stimulation, secretory granules were released from this reservoir to replenish the pool of newcomer secretory granules for subsequent fusion, occurring just adjacent to the plasma membrane Kv2.1 clusters. C1b deletion blocked the aforementioned Kv2.1-Syn-3-mediated events and reduced fusion of newcomer secretory granules. These insights have therapeutic implications, as Kv2.1 overexpression in type-2 diabetes rat islets restored biphasic insulin secretion.
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Affiliation(s)
- Dafna Greitzer-Antes
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Li Xie
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Tairan Qin
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Huanli Xie
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Dan Zhu
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Subhankar Dolai
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Tao Liang
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Fei Kang
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Alexandre B Hardy
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Yan He
- the Department of Epidemiology and Health Statistics, School of Public Health and Family Medicine, Capital Medical University, Beijing 100050, China
| | - Youhou Kang
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Herbert Y Gaisano
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
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26
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Tanner MR, Beeton C. Differences in ion channel phenotype and function between humans and animal models. FRONT BIOSCI-LANDMRK 2018; 23:43-64. [PMID: 28930537 PMCID: PMC5626566 DOI: 10.2741/4581] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ion channels play crucial roles in regulating a broad range of physiological processes. They form a very large family of transmembrane proteins. Their diversity results from not only a large number of different genes encoding for ion channel subunits but also the ability of subunits to assemble into homo- or heteromultimers, the existence of splice variants, and the expression of different regulatory subunits. These characteristics and the existence of very selective modulators make ion channels very attractive targets for therapy in a wide variety of pathologies. Some ion channels are already being targeted in the clinic while many more are being evaluated as novel drug targets in both clinical and preclinical studies. Advancing ion channel modulators from the bench to the clinic requires their assessment for safety and efficacy in animal models. While extrapolating results from one species to another is tempting, doing such without careful evaluation of the ion channels in different species presents a risk as the translation is not always straightforward. Here, we discuss differences between species in terms of ion channels expressed in selected tissues, differing roles of ion channels in some cell types, variable response to pharmacological agents, and human channelopathies that cannot fully be replicated in animal models.
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Affiliation(s)
- Mark R Tanner
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston TX 77030, and Interdepartmental Graduate Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston TX 77030
| | - Christine Beeton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston TX 77030, and Center for Drug Discovery and Biology of Inflammation Center, Baylor College of Medicine, Houston TX 77030,
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27
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Lee CH, Chu CS, Tsai HJ, Ke LY, Lee HC, Yeh JL, Chen CH, Wu BN. Xanthine-derived KMUP-1 reverses glucotoxicity-activated Kv channels through the cAMP/PKA signaling pathway in rat pancreatic β cells. Chem Biol Interact 2017; 279:171-176. [PMID: 29183753 DOI: 10.1016/j.cbi.2017.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/23/2017] [Indexed: 10/18/2022]
Abstract
Hyperglycemia-associated glucotoxicity induces β-cell dysfunction and a reduction in insulin secretion. Voltage-dependent K+ (Kv) channels in pancreatic β-cells play a key role in glucose-dependent insulin secretion. KMUP-1, a xanthine derivative, has been demonstrated to modulate Kv channel activity in smooth muscles; however, the role of KMUP-1 in glucotoxicity-activated Kv channels in pancreatic β-cells remains unclear. In this study we examined the mechanisms by which KMUP-1 could inhibit high glucose (25 mM) activated Kv currents (IKv) in pancreatic β-cells. Pancreatic β-cells were isolated from Wistar rats and IKv was monitored by perforated patch-clamp recording. The peak IKv in high glucose-treated β-cells was ∼1.4-fold greater than for normal glucose (5.6 mM). KMUP-1 (1, 10, 30 μM) prevented high glucose-stimulated IKv in a concentration-dependent manner. Reduction of high glucose-activated IKv was also found for protein kinase A (PKA) activator 8-Br-cAMP (100 μM). Additionally, KMUP-1 (30 μM) current inhibition was reversed by the PKA inhibitor H-89 (1 μM). Otherwise, pretreatment with the PKC activator or inhibitor had no effect on IKv in high glucose exposure. In conclusion, glucotoxicity-diminished insulin secretion was due to IKv activation. KMUP-1 attenuated high glucose-stimulated IKv via the PKA but not the PKC signaling pathway. This finding provides evidence that KMUP-1 might be a promising agent for treating hyperglycemia-induced insulin resistance.
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Affiliation(s)
- Chien-Hsing Lee
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Chih-Sheng Chu
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Han-Jie Tsai
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Liang-Yin Ke
- Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Jwu-Lai Yeh
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Chu-Huang Chen
- Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Vascular and Medicinal Research, Texas Heart Institute, Houston, TX 77030, USA
| | - Bin-Nan Wu
- Department of Pharmacology, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan.
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28
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Skelin Klemen M, Dolenšek J, Slak Rupnik M, Stožer A. The triggering pathway to insulin secretion: Functional similarities and differences between the human and the mouse β cells and their translational relevance. Islets 2017; 9:109-139. [PMID: 28662366 PMCID: PMC5710702 DOI: 10.1080/19382014.2017.1342022] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In β cells, stimulation by metabolic, hormonal, neuronal, and pharmacological factors is coupled to secretion of insulin through different intracellular signaling pathways. Our knowledge about the molecular machinery supporting these pathways and the patterns of signals it generates comes mostly from rodent models, especially the laboratory mouse. The increased availability of human islets for research during the last few decades has yielded new insights into the specifics in signaling pathways leading to insulin secretion in humans. In this review, we follow the most central triggering pathway to insulin secretion from its very beginning when glucose enters the β cell to the calcium oscillations it produces to trigger fusion of insulin containing granules with the plasma membrane. Along the way, we describe the crucial building blocks that contribute to the flow of information and focus on their functional role in mice and humans and on their translational implications.
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Affiliation(s)
- Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marjan Slak Rupnik
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Institute of Physiology; Center for Physiology and Pharmacology; Medical University of Vienna; Vienna, Austria
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
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29
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Wu Y, Fortin DA, Cochrane VA, Chen PC, Shyng SL. NMDA receptors mediate leptin signaling and regulate potassium channel trafficking in pancreatic β-cells. J Biol Chem 2017; 292:15512-15524. [PMID: 28768770 DOI: 10.1074/jbc.m117.802249] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/01/2017] [Indexed: 12/25/2022] Open
Abstract
NMDA receptors (NMDARs) are Ca2+-permeant, ligand-gated ion channels activated by the excitatory neurotransmitter glutamate and have well-characterized roles in the nervous system. The expression and function of NMDARs in pancreatic β-cells, by contrast, are poorly understood. Here, we report a novel function of NMDARs in β-cells. Using a combination of biochemistry, electrophysiology, and imaging techniques, we now show that NMDARs have a key role in mediating the effect of leptin to modulate β-cell electrical activity by promoting AMP-activated protein kinase (AMPK)-dependent trafficking of KATP and Kv2.1 channels to the plasma membrane. Blocking NMDAR activity inhibited the ability of leptin to activate AMPK, induce KATP and Kv2.1 channel trafficking, and promote membrane hyperpolarization. Conversely, activation of NMDARs mimicked the effect of leptin, causing Ca2+ influx, AMPK activation, and increased trafficking of KATP and Kv2.1 channels to the plasma membrane, and triggered membrane hyperpolarization. Moreover, leptin potentiated NMDAR currents and triggered NMDAR-dependent Ca2+ influx. Importantly, NMDAR-mediated signaling was observed in rat insulinoma 832/13 cells and in human β-cells, indicating that this pathway is conserved across species. The ability of NMDARs to regulate potassium channel surface expression and thus, β-cell excitability provides mechanistic insight into the recently reported insulinotropic effects of NMDAR antagonists and therefore highlights the therapeutic potential of these drugs in managing type 2 diabetes.
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Affiliation(s)
- Yi Wu
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Dale A Fortin
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Veronica A Cochrane
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Pei-Chun Chen
- the Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Show-Ling Shyng
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
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30
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Fu J, Dai X, Plummer G, Suzuki K, Bautista A, Githaka JM, Senior L, Jensen M, Greitzer-Antes D, Manning Fox JE, Gaisano HY, Newgard CB, Touret N, MacDonald PE. Kv2.1 Clustering Contributes to Insulin Exocytosis and Rescues Human β-Cell Dysfunction. Diabetes 2017; 66:1890-1900. [PMID: 28607108 PMCID: PMC5482075 DOI: 10.2337/db16-1170] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 04/15/2017] [Indexed: 12/12/2022]
Abstract
Insulin exocytosis is regulated by ion channels that control excitability and Ca2+ influx. Channels also play an increasingly appreciated role in microdomain structure. In this study, we examine the mechanism by which the voltage-dependent K+ (Kv) channel Kv2.1 (KCNB1) facilitates depolarization-induced exocytosis in INS 832/13 cells and β-cells from human donors with and without type 2 diabetes (T2D). We find that Kv2.1, but not Kv2.2 (KCNB2), forms clusters of 6-12 tetrameric channels at the plasma membrane and facilitates insulin exocytosis. Knockdown of Kv2.1 expression reduces secretory granule targeting to the plasma membrane. Expression of the full-length channel (Kv2.1-wild-type) supports the glucose-dependent recruitment of secretory granules. However, a truncated channel (Kv2.1-ΔC318) that retains electrical function and syntaxin 1A binding, but lacks the ability to form clusters, does not enhance granule recruitment or exocytosis. Expression of KCNB1 appears reduced in T2D islets, and further knockdown of KCNB1 does not inhibit Kv current in T2D β-cells. Upregulation of Kv2.1-wild-type, but not Kv2.1-ΔC318, rescues the exocytotic phenotype in T2D β-cells and increases insulin secretion from T2D islets. Thus, the ability of Kv2.1 to directly facilitate insulin exocytosis depends on channel clustering. Loss of this structural role for the channel might contribute to impaired insulin secretion in diabetes.
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Affiliation(s)
- Jianyang Fu
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Xiaoqing Dai
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Gregory Plummer
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Kunimasa Suzuki
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Austin Bautista
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - John M Githaka
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Laura Senior
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Mette Jensen
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Departments of Pharmacology & Cancer Biology and Medicine, Duke University, Durham, NC
| | - Dafna Greitzer-Antes
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jocelyn E Manning Fox
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Herbert Y Gaisano
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Departments of Pharmacology & Cancer Biology and Medicine, Duke University, Durham, NC
| | - Nicolas Touret
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick E MacDonald
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
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31
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Liu Y, Zhong X, Ding Y, Ren L, Bai T, Liu M, Liu Z, Guo Y, Guo Q, Zhang Y, Yang J, Zhang Y. Inhibition of voltage-dependent potassium channels mediates cAMP-potentiated insulin secretion in rat pancreatic β cells. Islets 2017; 9:11-18. [PMID: 28103136 PMCID: PMC5345751 DOI: 10.1080/19382014.2017.1280644] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Insulin secretion is essential for maintenance of glucose homeostasis. An important intracellular signal regulating insulin secretion is cAMP. In this report, we showed that an increase of cAMP induced by adenylyl cyclase (AC) activator forskolin or by cAMP analog db-cAMP not only potentiated insulin secretion but also inhibited Kv channels, and these effects were reversed by AC inhibitor SQ22536. The cAMP-mediated Kv channel inhibition resulted in prolongation of action potential duration, which partly accounts for the elevation of intracellular Ca2+ induced by activation of cAMP signaling. Taken together, the results suggest that Kv channels are involved in cAMP-potentiated insulin secretion in pancreatic β cells.
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Affiliation(s)
- Yunfeng Liu
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
- CONTACT Yunfeng Liu Department of Endocrinology, The first Hospital of Shanxi Medical University, Taiyuan 030001, China; Yi Zhang , Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China
| | - Xiangqin Zhong
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yaqin Ding
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Lele Ren
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Tao Bai
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Mengmeng Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Zhihong Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Yangyan Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yu Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Jing Yang
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
- CONTACT Yunfeng Liu Department of Endocrinology, The first Hospital of Shanxi Medical University, Taiyuan 030001, China; Yi Zhang , Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China
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32
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Gao J, Bai T, Ren L, Ding Y, Zhong X, Wang H, Guo Y, Li J, Liu Y, Zhang Y. The PLC/PKC/Ras/MEK/Kv channel pathway is involved in uncarboxylated osteocalcin-regulated insulin secretion in rats. Peptides 2016; 86:72-79. [PMID: 27746193 DOI: 10.1016/j.peptides.2016.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 09/22/2016] [Accepted: 10/10/2016] [Indexed: 12/11/2022]
Abstract
Uncarboxylated osteocalcin, a bone matrix protein, has been proposed to regulate glucose metabolism by increasing insulin secretion, improving insulin sensitivity and stimulating β cell proliferation. Our previous study also indicated that uncarboxylated osteocalcin stimulates insulin secretion by inhibiting voltage-gated potassium (KV) channels. The goal of this study is to further investigate the underlying mechanisms for the regulation of Kv channels and insulin secretion by uncarboxylated osteocalcin. Insulin secretion and Kv channel currents were examined by radioimmunoassay and patch-clamp technique, respectively. Calcium imaging system was applied to measure intracellular Ca2+ concentration ([Ca2+]i). The protein levels were detected by western blot. The results showed that uncarboxylated osteocalcin potentiated insulin secretion, inhibited Kv channels and increased [Ca2+]i compared to control. These effects were suppressed by phospholipase-C (PLC)/protein kinase C (PKC)/Ras/MAPK-ERK kinase (MEK) signaling pathway, indicating that this signaling pathway plays an important role in uncarboxylated osteocalcin-regulated insulinotropic effect. In addition, the results also showed that adenylyl cyclase (AC) did not influence the effect of uncarboxylated osteocalcin on insulin secretion and Kv channels, suggesting that AC is not involved in uncarboxylated osteocalcin-stimulated insulin secretion. These findings provide new insight into the mechanism of uncarboxylated osteocalcin-regulated insulin secretion.
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Affiliation(s)
- Jingying Gao
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China; Department of Pediatrics, Shanxi Medical University, Taiyuan, China
| | - Tao Bai
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China; Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Lele Ren
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yaqin Ding
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Xiangqin Zhong
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Hui Wang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yangyan Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Jie Li
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yunfeng Liu
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China; Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China.
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33
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Pucca MB, Bertolini TB, Cerni FA, Bordon KCF, Peigneur S, Tytgat J, Bonato VL, Arantes EC. Immunosuppressive evidence of Tityus serrulatus toxins Ts6 and Ts15: insights of a novel K(+) channel pattern in T cells. Immunology 2016; 147:240-50. [PMID: 26595158 DOI: 10.1111/imm.12559] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 12/25/2022] Open
Abstract
The voltage-gated potassium channel Kv1.3 is a novel target for immunomodulation of autoreactive effector memory T cells, which play a major role in the pathogenesis of autoimmune diseases. In this study, the Ts6 and Ts15 toxins isolated from Tityus serrulatus (Ts) were investigated for their immunosuppressant roles on CD4(+) cell subsets: naive, effector (TEF ), central memory (TCM) and effector memory (TEM). The electrophysiological assays confirmed that both toxins were able to block Kv1.3 channels. Interestingly, an extended Kv channel screening shows that Ts15 blocks Kv2.1 channels. Ts6 and Ts15 significantly inhibit the proliferation of TEM cells and interferon-γ production; however, Ts15 also inhibits other CD4(+) cell subsets (naive, TEF and TCM). Based on the Ts15 inhibitory effect of proliferation of all CD4(+) cell subsets, and based on its blocking effect on Kv2.1, we investigated the Kv2.1 expression in T cells. The assays showed that CD4(+) and CD8(+) cells express the Kv2.1 channels mainly extracellularly with TCM cells expressing the highest number of Kv2.1 channels. We also provide in vivo experimental evidence to the protective effect of Ts6 and Ts15 on delayed-type hypersensitivity reaction. Altogether, this study presents the immunosuppressive behaviour of Ts6 and Ts15 toxins, indicating that these toxins could be promising candidates for autoimmune disease therapy. Moreover, this is the first report illustrating the involvement of a novel K(+) channel subtype, Kv2.1, and its distribution in T-cell subsets.
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Affiliation(s)
- Manuela B Pucca
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Thaís B Bertolini
- Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Felipe A Cerni
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Karla C F Bordon
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, Leuven, Belgium
| | - Vânia L Bonato
- Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Eliane C Arantes
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Zhou TT, Quan LL, Chen LP, Du T, Sun KX, Zhang JC, Yu L, Li Y, Wan P, Chen LL, Jiang BH, Hu LH, Chen J, Shen X. SP6616 as a new Kv2.1 channel inhibitor efficiently promotes β-cell survival involving both PKC/Erk1/2 and CaM/PI3K/Akt signaling pathways. Cell Death Dis 2016; 7:e2216. [PMID: 27148689 PMCID: PMC4917657 DOI: 10.1038/cddis.2016.119] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 12/31/2022]
Abstract
Kv2.1 as a voltage-gated potassium (Kv) channel subunit has a pivotal role in the regulation of glucose-stimulated insulin secretion (GSIS) and pancreatic β-cell apoptosis, and is believed to be a promising target for anti-diabetic drug discovery, although the mechanism underlying the Kv2.1-mediated β-cell apoptosis is obscure. Here, the small molecular compound, ethyl 5-(3-ethoxy-4-methoxyphenyl)-2-(4-hydroxy-3-methoxybenzylidene)-7-methyl-3-oxo-2,3-dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidine-6-carboxylate (SP6616) was discovered to be a new Kv2.1 inhibitor. It was effective in both promoting GSIS and protecting β cells from apoptosis. Evaluation of SP6616 on either high-fat diet combined with streptozocin-induced type 2 diabetic mice or db/db mice further verified its efficacy in the amelioration of β-cell dysfunction and glucose homeostasis. SP6616 treatment efficiently increased serum insulin level, restored β-cell mass, decreased fasting blood glucose and glycated hemoglobin levels, and improved oral glucose tolerance. Mechanism study indicated that the promotion of SP6616 on β-cell survival was tightly linked to its regulation against both protein kinases C (PKC)/extracellular-regulated protein kinases 1/2 (Erk1/2) and calmodulin(CaM)/phosphatidylinositol 3-kinase(PI3K)/serine/threonine-specific protein kinase (Akt) signaling pathways. To our knowledge, this may be the first report on the underlying pathway responsible for the Kv2.1-mediated β-cell protection. In addition, our study has also highlighted the potential of SP6616 in the treatment of type 2 diabetes.
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Affiliation(s)
- T T Zhou
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - L L Quan
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - L P Chen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - T Du
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - K X Sun
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - J C Zhang
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - L Yu
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Y Li
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - P Wan
- College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China
| | - L L Chen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - B H Jiang
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - L H Hu
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - J Chen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - X Shen
- CAS Key Laboratory of Receptor Research, 3th Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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Inhibition of voltage-gated potassium channels mediates uncarboxylated osteocalcin-regulated insulin secretion in rat pancreatic β cells. Eur J Pharmacol 2016; 777:41-8. [DOI: 10.1016/j.ejphar.2016.02.060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/23/2016] [Accepted: 02/26/2016] [Indexed: 01/17/2023]
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Bocksteins E. Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders. J Gen Physiol 2016; 147:105-25. [PMID: 26755771 PMCID: PMC4727947 DOI: 10.1085/jgp.201511507] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/11/2015] [Indexed: 12/19/2022] Open
Abstract
Members of the electrically silent voltage-gated K(+) (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K(+) channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.
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Affiliation(s)
- Elke Bocksteins
- Laboratory for Molecular Biophysics, Physiology, and Pharmacology, Department for Biomedical Sciences, University of Antwerp, 2610 Antwerp, Belgium
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37
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Wu Y, Shyng SL, Chen PC. Concerted Trafficking Regulation of Kv2.1 and KATP Channels by Leptin in Pancreatic β-Cells. J Biol Chem 2015; 290:29676-90. [PMID: 26453299 DOI: 10.1074/jbc.m115.670877] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Indexed: 11/06/2022] Open
Abstract
In pancreatic β-cells, voltage-gated potassium 2.1 (Kv2.1) channels are the dominant delayed rectifier potassium channels responsible for action potential repolarization. Here, we report that leptin, a hormone secreted by adipocytes known to inhibit insulin secretion, causes a transient increase in surface expression of Kv2.1 channels in rodent and human β-cells. The effect of leptin on Kv2.1 surface expression is mediated by the AMP-activated protein kinase (AMPK). Activation of AMPK mimics whereas inhibition of AMPK occludes the effect of leptin. Inhibition of Ca(2+)/calmodulin-dependent protein kinase kinase β, a known upstream kinase of AMPK, also blocks the effect of leptin. In addition, the cAMP-dependent protein kinase (PKA) is involved in Kv2.1 channel trafficking regulation. Inhibition of PKA prevents leptin or AMPK activators from increasing Kv2.1 channel density, whereas stimulation of PKA is sufficient to promote Kv2.1 channel surface expression. The increased Kv2.1 surface expression by leptin is dependent on actin depolymerization, and pharmacologically induced actin depolymerization is sufficient to enhance Kv2.1 surface expression. The signaling and cellular mechanisms underlying Kv2.1 channel trafficking regulation by leptin mirror those reported recently for ATP-sensitive potassium (KATP) channels, which are critical for coupling glucose stimulation with membrane depolarization. We show that the leptin-induced increase in surface KATP channels results in more hyperpolarized membrane potentials than control cells at stimulating glucose concentrations, and the increase in Kv2.1 channels leads to a more rapid repolarization of membrane potential in cells firing action potentials. This study supports a model in which leptin exerts concerted trafficking regulation of KATP and Kv2.1 channels to coordinately inhibit insulin secretion.
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Affiliation(s)
- Yi Wu
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Show-Ling Shyng
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Pei-Chun Chen
- the Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
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38
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Zhang Y, Wang H, Guo Q, Li X, Gao J, Liu Y, Yang C, Niu L, Yang J. PI3K is involved in P2Y receptor-regulated cAMP /Epac/Kv channel signaling pathway in pancreatic β cells. Biochem Biophys Res Commun 2015; 465:714-8. [PMID: 26296468 DOI: 10.1016/j.bbrc.2015.08.057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 12/20/2022]
Abstract
P2Y receptors (P2YR) are a family of purinergic G protein-coupled receptors, which could be stimulated by extracellular nucleotides. In pancreatic β cells, activation of P2YR has long been shown to stimulate insulin secretion in a glucose-dependent manner. Previously, we reported that P2YR-modulated insulin secretion is mediated by a cAMP/Epac/Kv channel pathway. However, the interaction between Epac and the Kv channel in P2YR-modulated insulin secretion remains unclear. In this study, we used patch-clamp technique and insulin secretion assay to investigate the potential molecules that may link Epac to Kv channel inhibition induced by P2YR activation. We identified that phosphatidylinositide 3-kinase, which mediates P2YR-regulated insulin secretion, is a critical mediator between Epac and the Kv channel.
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Affiliation(s)
- Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Hui Wang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Xiaodong Li
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Jingying Gao
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Yunfeng Liu
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
| | - Caihong Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Longgang Niu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Jing Yang
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
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Zhang Y, Guo Q, Li X, Gao J, Liu Y, Yang J, Li Q. P2Y purinergic receptor-regulated insulin secretion is mediated by a cAMP/Epac/Kv channel pathway. Biochem Biophys Res Commun 2015; 460:850-6. [PMID: 25839655 DOI: 10.1016/j.bbrc.2015.03.121] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 03/21/2015] [Indexed: 10/23/2022]
Abstract
Enhancement of insulin secretion is a major therapeutic approach for type 2 diabetes (T2D). Activation of P2Y purinergic receptor (P2YR) causes potentiation of insulin secretion in a glucose-dependent manner, making it a promising therapeutic target for T2D. Here we show that activation of P2YR to potentiate insulin secretion is mediated by adenylyl cyclase/cyclic AMP (cAMP) and the downstream effector, exchange protein directly activated by cAMP (Epac), leading to inhibition of voltage-dependent potassium (Kv) channels. P2YR-mediated Kv channel inhibition results in prolongation of action potential duration, and in turn elevates intracellular Ca(2+) level and insulin secretion. Taken together, the data indicate that cAMP/Epac/Kv channel pathway mediates P2YR-regulated insulin secretion, which may have important therapeutic implications for T2D.
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Affiliation(s)
- Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China.
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China.
| | - Xiaodong Li
- Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China.
| | - Jingying Gao
- Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China.
| | - Yunfeng Liu
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
| | - Jing Yang
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
| | - Qingshan Li
- School of Pharmaceutical Sciences, Shanxi Medical University, Taiyuan, China.
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40
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Kim H, Yang I, Ryu SY, Won DH, Giri AG, Wang W, Choi H, Chin J, Hahn D, Kim E, Han C, Lee J, Nam SJ, Ho WK, Kang H. Acredinones A and B, voltage-dependent potassium channel inhibitors from the sponge-derived fungus Acremonium sp. F9A015. JOURNAL OF NATURAL PRODUCTS 2015; 78:363-367. [PMID: 25689430 DOI: 10.1021/np5007586] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Two new benzophenones, acredinones A (1) and B (2), were isolated from a marine-sponge-associated Acremonium sp. fungus. Their chemical structures were elucidated on the interpretation of spectroscopic data. The structure of 1 was confirmed by palladium-catalyzed hydrogenation, followed by spectroscopic data analysis. Acredinones A (1) and B (2) inhibited the outward K(+) currents of the insulin secreting cell line INS-1 with IC50 values of 0.59 and 1.0 μM, respectively.
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Affiliation(s)
- Hiyoung Kim
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Inho Yang
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Shin-Young Ryu
- ‡National Research Laboratory for Cell Physiology and Department of Physiology, Seoul National University College of Medicine, 28 Yonkeun-Dong, Chongno-Ku, Seoul 110-799, Korea
| | - Dong Hwan Won
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Awadut G Giri
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Weihong Wang
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Hyukjae Choi
- §College of Pharmacy, Yeungnam University, 214-1 Dae-dong, Gyeongsan 712-749, Korea
| | - Jungwook Chin
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Dongyup Hahn
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Eunhee Kim
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Chulkyeong Han
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Jihye Lee
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
| | - Sang-Jip Nam
- ⊥Department of Chemistry and Nano Science, Global Top 5 Program, Ewha Womans University, Seoul 120-750, Korea
| | - Won-Kyung Ho
- ‡National Research Laboratory for Cell Physiology and Department of Physiology, Seoul National University College of Medicine, 28 Yonkeun-Dong, Chongno-Ku, Seoul 110-799, Korea
| | - Heonjoong Kang
- †Center for Marine Natural Products and Drug Discovery, School of Earth and Environmental Sciences, Seoul National University, NS-80, Seoul 151-747, Korea
- ∥Research Institute of Oceanography, Seoul National University, NS-80, Seoul 151-747, Korea
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Sukma Rita R, Dezaki K, Kurashina T, Kakei M, Yada T. Partial blockade of Kv2.1 channel potentiates GLP-1's insulinotropic effects in islets and reduces its dose required for improving glucose tolerance in type 2 diabetic male mice. Endocrinology 2015; 156:114-23. [PMID: 25337656 DOI: 10.1210/en.2014-1728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucagon-like peptide-1 (GLP-1)-based medicines have recently been widely used to treat type 2 diabetic patients, whereas adverse effects of nausea and vomiting have been documented. Inhibition of voltage-gated K(+) channel subtype Kv2.1 in pancreatic β-cells has been suggested to contribute to mild depolarization and promotion of insulin release. This study aimed to determine whether the blockade of Kv2.1 channels potentiates the insulinotropic effect of GLP-1 agonists. Kv2.1 channel blocker guangxitoxin-1E (GxTx) and GLP-1 agonist exendin-4 at subthreshold concentrations, when combined, markedly increased the insulin release and cytosolic Ca(2+) concentration ([Ca(2+)]i) in a glucose-dependent manner in mouse islets and β-cells. Exendin-4 at subthreshold concentration alone increased islet insulin release and β-cell [Ca(2+)]i in Kv2.1(+/-) mice. The [Ca(2+)]i response to subthreshold exendin-4 and GxTx in combination was attenuated by pretreatment with protein kinase A inhibitor H-89, indicating the protein kinase A dependency of the cooperative effect. Furthermore, subthreshold doses of GxTx and GLP-1 agonist liraglutide in combination markedly increased plasma insulin and improved glucose tolerance in diabetic db/db mice and NSY mice. These results demonstrate that a modest suppression of Kv2.1 channels dramatically raises insulinotropic potency of GLP-1-based drugs, which opens a new avenue to reduce their doses and associated adverse effects while achieving the same glycemic control in type 2 diabetes.
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Affiliation(s)
- Rauza Sukma Rita
- Division of Integrative Physiology (R.S.R., K.D., T.K., T.Y.), Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan; Department of Internal Medicine (M.K.), Saitama Medical Center, Jichi Medical University School of Medicine, Saitama 337-8503, Japan; and Department of Development Physiology (T.Y.), Division of Adaptation Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
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42
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Antonucci S, Tagliavini A, Pedersen MG. Reactive oxygen and nitrogen species disturb Ca(2+) oscillations in insulin-secreting MIN6 β-cells. Islets 2015; 7:e1107255. [PMID: 26732126 PMCID: PMC4878267 DOI: 10.1080/19382014.2015.1107255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Disturbances in pulsatile insulin secretion and Ca(2+) oscillations in pancreatic β-cells are early markers of diabetes, but the underlying mechanisms are still incompletely understood. Reactive oxygen/nitrogen species (ROS/RNS) are implicated in reduced β-cell function, and ROS/RNS target several Ca(2+) pumps and channels. Thus, we hypothesized that ROS/RNS could disturb Ca(2+) oscillations and downstream insulin pulsatility. We show that ROS/RNS production by photoactivation of aluminum phthalocyanine chloride (AlClPc) abolish or accelerate Ca(2+) oscillations in the MIN6 β-cell line, depending on the amount of ROS/RNS. Application of the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitor thapsigargin modifies the Ca(2+) response to high concentrations of ROS/RNS. Further, thapsigargin produces effects that resemble those elicited by moderate ROS/RNS production. These results indicate that ROS/RNS interfere with endoplasmic reticulum Ca(2+) handling. This idea is supported by theoretical studies using a mathematical model of Ca(2+) handling adapted to MIN6 cells. Our results suggest a putative link between ROS/RNS and disturbed pulsatile insulin secretion.
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Affiliation(s)
- Salvatore Antonucci
- Department of Biomedical Sciences; University of Padua; Padua, Italy
- Venetian Institute of Molecular Medicine; Padua, Italy
| | - Alessia Tagliavini
- Department of Information Engineering; University of Padua; Padua, Italy
| | - Morten Gram Pedersen
- Department of Information Engineering; University of Padua; Padua, Italy
- Correspondence to: Morten Gram Pedersen;
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Yang SN, Shi Y, Yang G, Li Y, Yu J, Berggren PO. Ionic mechanisms in pancreatic β cell signaling. Cell Mol Life Sci 2014; 71:4149-77. [PMID: 25052376 PMCID: PMC11113777 DOI: 10.1007/s00018-014-1680-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/03/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
The function and survival of pancreatic β cells critically rely on complex electrical signaling systems composed of a series of ionic events, namely fluxes of K(+), Na(+), Ca(2+) and Cl(-) across the β cell membranes. These electrical signaling systems not only sense events occurring in the extracellular space and intracellular milieu of pancreatic islet cells, but also control different β cell activities, most notably glucose-stimulated insulin secretion. Three major ion fluxes including K(+) efflux through ATP-sensitive K(+) (KATP) channels, the voltage-gated Ca(2+) (CaV) channel-mediated Ca(2+) influx and K(+) efflux through voltage-gated K(+) (KV) channels operate in the β cell. These ion fluxes set the resting membrane potential and the shape, rate and pattern of firing of action potentials under different metabolic conditions. The KATP channel-mediated K(+) efflux determines the resting membrane potential and keeps the excitability of the β cell at low levels. Ca(2+) influx through CaV1 channels, a major type of β cell CaV channels, causes the upstroke or depolarization phase of the action potential and regulates a wide range of β cell functions including the most elementary β cell function, insulin secretion. K(+) efflux mediated by KV2.1 delayed rectifier K(+) channels, a predominant form of β cell KV channels, brings about the downstroke or repolarization phase of the action potential, which acts as a brake for insulin secretion owing to shutting down the CaV channel-mediated Ca(2+) entry. These three ion channel-mediated ion fluxes are the most important ionic events in β cell signaling. This review concisely discusses various ionic mechanisms in β cell signaling and highlights KATP channel-, CaV1 channel- and KV2.1 channel-mediated ion fluxes.
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Affiliation(s)
- Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76, Stockholm, Sweden,
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Dadi PK, Vierra NC, Jacobson DA. Pancreatic β-cell-specific ablation of TASK-1 channels augments glucose-stimulated calcium entry and insulin secretion, improving glucose tolerance. Endocrinology 2014; 155:3757-68. [PMID: 24932805 PMCID: PMC4164933 DOI: 10.1210/en.2013-2051] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Calcium entry through voltage-dependent Ca(2+) channels (VDCCs) is required for pancreatic β-cell insulin secretion. The 2-pore-domain acid-sensitive potassium channel (TASK-1) regulates neuronal excitability and VDCC activation by hyperpolarizing the plasma membrane potential (Δψp); however, a role for pancreatic β-cell TASK-1 channels is unknown. Here we examined the influence of TASK-1 channel activity on the β-cell Δψp and insulin secretion during secretagogue stimulation. TASK-1 channels were found to be highly expressed in human and rodent islets and localized to the plasma membrane of β-cells. TASK-1-like currents of mouse and human β-cells were blocked by the potent TASK-1 channel inhibitor, A1899 (250nM). Although inhibition of TASK-1 currents did not influence the β-cell Δψp in the presence of low (2mM) glucose, A1899 significantly enhanced glucose-stimulated (14mM) Δψp depolarization of human and mouse β-cells. TASK-1 inhibition also resulted in greater secretagogue-stimulated Ca(2+) influx in both human and mouse islets. Moreover, conditional ablation of mouse β-cell TASK-1 channels reduced K2P currents, increased glucose-stimulated Δψp depolarization, and augmented secretagogue-stimulated Ca(2+) influx. The Δψp depolarization caused by TASK-1 inhibition resulted in a transient increase in glucose-stimulated mouse β-cell action potential (AP) firing frequency. However, secretagogue-stimulated β-cell AP duration eventually increased in the presence of A1899 as well as in β-cells without TASK-1, causing a decrease in AP firing frequency. Ablation or inhibition of mouse β-cell TASK-1 channels also significantly enhanced glucose-stimulated insulin secretion, which improved glucose tolerance. Conversely, TASK-1 ablation did not perturb β-cell Δψp, Ca(2+) influx, or insulin secretion under low-glucose conditions (2mM). These results reveal a glucose-dependent role for β-cell TASK-1 channels of limiting glucose-stimulated Δψp depolarization and insulin secretion, which modulates glucose homeostasis.
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Affiliation(s)
- Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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Abstract
SIGNIFICANCE Voltage-gated K+ channels are a large family of K+-selective ion channel protein complexes that open on membrane depolarization. These K+ channels are expressed in diverse tissues and their function is vital for numerous physiological processes, in particular of neurons and muscle cells. Potentially reversible oxidative regulation of voltage-gated K+ channels by reactive species such as reactive oxygen species (ROS) represents a contributing mechanism of normal cellular plasticity and may play important roles in diverse pathologies including neurodegenerative diseases. RECENT ADVANCES Studies using various protocols of oxidative modification, site-directed mutagenesis, and structural and kinetic modeling provide a broader phenomenology and emerging mechanistic insights. CRITICAL ISSUES Physicochemical mechanisms of the functional consequences of oxidative modifications of voltage-gated K+ channels are only beginning to be revealed. In vivo documentation of oxidative modifications of specific amino-acid residues of various voltage-gated K+ channel proteins, including the target specificity issue, is largely absent. FUTURE DIRECTIONS High-resolution chemical and proteomic analysis of ion channel proteins with respect to oxidative modification combined with ongoing studies on channel structure and function will provide a better understanding of how the function of voltage-gated K+ channels is tuned by ROS and the corresponding reducing enzymes to meet cellular needs.
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Affiliation(s)
- Nirakar Sahoo
- 1 Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital , Jena, Germany
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46
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Genome-wide copy number variation study reveals KCNIP1 as a modulator of insulin secretion. Genomics 2014; 104:113-20. [DOI: 10.1016/j.ygeno.2014.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 05/19/2014] [Accepted: 05/23/2014] [Indexed: 01/09/2023]
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Zhang M, Robitaille M, Showalter AD, Huang X, Liu Y, Bhattacharjee A, Willard FS, Han J, Froese S, Wei L, Gaisano HY, Angers S, Sloop KW, Dai FF, Wheeler MB. Progesterone receptor membrane component 1 is a functional part of the glucagon-like peptide-1 (GLP-1) receptor complex in pancreatic β cells. Mol Cell Proteomics 2014; 13:3049-62. [PMID: 25044020 DOI: 10.1074/mcp.m114.040196] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is an incretin hormone that regulates glucose homeostasis. Because of their direct stimulation of insulin secretion from pancreatic β cells, GLP-1 receptor (GLP-1R) agonists are now important therapeutic options for the treatment of type 2 diabetes. To better understand the mechanisms that control the insulinotropic actions of GLP-1, affinity purification and mass spectrometry (AP-MS) were employed to uncover potential proteins that functionally interact with the GLP-1R. AP-MS performed on Chinese hamster ovary cells or MIN6 β cells, both expressing the human GLP-1R, revealed 99 proteins potentially associated with the GLP-1R. Three novel GLP-1R interactors (PGRMC1, Rab5b, and Rab5c) were further validated through co-immunoprecipitation/immunoblotting, fluorescence resonance energy transfer, and immunofluorescence. Functional studies revealed that overexpression of PGRMC1, a novel cell surface receptor that associated with liganded GLP-1R, enhanced GLP-1-induced insulin secretion (GIIS) with the most robust effect. Knockdown of PGRMC1 in β cells decreased GIIS, indicative of positive interaction with GLP-1R. To gain insight mechanistically, we demonstrated that the cell surface PGRMC1 ligand P4-BSA increased GIIS, whereas its antagonist AG-205 decreased GIIS. It was then found that PGRMC1 increased GLP-1-induced cAMP accumulation. PGRMC1 activation and GIIS induced by P4-BSA could be blocked by inhibition of adenylyl cyclase/EPAC signaling or the EGF receptor-PI3K signal transduction pathway. These data reveal a dual mechanism for PGRMC1-increased GIIS mediated through cAMP and EGF receptor signaling. In conclusion, we identified several novel GLP-1R interacting proteins. PGRMC1 expressed on the cell surface of β cells was shown to interact with the activated GLP-1R to enhance the insulinotropic actions of GLP-1.
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Affiliation(s)
- Ming Zhang
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7
| | - Mélanie Robitaille
- ¶Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, and Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 3M2
| | - Aaron D Showalter
- ‖Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, 46285
| | - Xinyi Huang
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7
| | - Ying Liu
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8
| | - Alpana Bhattacharjee
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8
| | - Francis S Willard
- ‖‖Quantitative Biology, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, 46285
| | - Junfeng Han
- **Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China 200233
| | - Sean Froese
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7
| | - Li Wei
- **Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China 200233
| | - Herbert Y Gaisano
- ‡‡Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8
| | - Stéphane Angers
- ¶Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, and Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 3M2
| | - Kyle W Sloop
- ‖Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, 46285
| | - Feihan F Dai
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8;
| | - Michael B Wheeler
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7;
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Yang J, Liu J, Liu J, Li W, Li X, He Y, Ye L. Genetic association study with metabolic syndrome and metabolic-related traits in a cross-sectional sample and a 10-year longitudinal sample of chinese elderly population. PLoS One 2014; 9:e100548. [PMID: 24959828 PMCID: PMC4069025 DOI: 10.1371/journal.pone.0100548] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 05/29/2014] [Indexed: 11/18/2022] Open
Abstract
Background The metabolic syndrome (MetS) has been known as partly heritable, while the number of genetic studies on MetS and metabolic-related traits among Chinese elderly was limited. Methods A cross-sectional analysis was performed among 2 014 aged participants from September 2009 to June 2010 in Beijing, China. An additional longitudinal study was carried out among the same study population from 2001 to 2010. Biochemical profile and anthropometric parameters of all the participants were measured. The associations of 23 SNPs located within 17 candidate genes (MTHFR, PPARγ, LPL, INSIG, TCF7L2, FTO, KCNJ11, JAZF1, CDKN2A/B, ADIPOQ, WFS1, CDKAL1, IGF2BP2, KCNQ1, MTNR1B, IRS1, ACE) with overweight and obesity, diabetes, metabolic phenotypes, and MetS were examined in both studies. Results In this Chinese elderly population, prevalence of overweight, central obesity, diabetes, dyslipidemia, hypertension, and MetS were 48.3%, 71.0%, 32.4%, 75.7%, 68.3% and 54.5%, respectively. In the cross-sectional analyses, no SNP was found to be associated with MetS. Genotype TT of SNP rs4402960 within the gene IGF2BP2 was associated with overweight (odds ratio (OR) = 0.479, 95% confidence interval (CI): 0.316-0.724, p = 0.001) and genotype CA of SNP rs1801131 within the gene MTHFR was associated with hypertension (OR = 1.560, 95% CI: 1.194–2.240, p = 0.001). However, these associations were not observed in the longitudinal analyses. Conclusions The associations of SNP rs4402960 with overweight as well as the association of SNP rs1801131 with hypertension were found to be statistically significant. No SNP was identified to be associated with MetS in our study with statistical significance.
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Affiliation(s)
- Jinghui Yang
- Institute of Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- Beijing Key Lab of Aging and Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
| | - Jianwei Liu
- Institute of Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- Beijing Key Lab of Aging and Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
| | - Jing Liu
- Institute of Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- Beijing Key Lab of Aging and Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
| | - Wenyuan Li
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Xiaoying Li
- Institute of Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- Department of Geriatric Cardiology, the General Hospital of the People's Liberation Army, Beijing, China
| | - Yao He
- Institute of Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- Beijing Key Lab of Aging and Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- * E-mail: (LY); (YH)
| | - Ling Ye
- Institute of Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- Beijing Key Lab of Aging and Geriatrics, the General Hospital of the People's Liberation Army, Beijing, China
- * E-mail: (LY); (YH)
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Li X, Guo Q, Gao J, Yang J, Zhang W, Liang Y, Wu D, Liu Y, Weng J, Li Q, Zhang Y. The adenylyl cyclase inhibitor MDL-12,330A potentiates insulin secretion via blockade of voltage-dependent K(+) channels in pancreatic beta cells. PLoS One 2013; 8:e77934. [PMID: 24205033 PMCID: PMC3812155 DOI: 10.1371/journal.pone.0077934] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 09/06/2013] [Indexed: 12/25/2022] Open
Abstract
Objective Adenylyl cyclases (ACs) play important role in regulating pancreatic beta cell growth, survival and secretion through the synthesis of cyclic AMP (cAMP). MDL-12,330A and SQ 22536 are two AC inhibitors used widely to establish the role of ACs. The goal of this study was to examine the effects of MDL-12,330A and SQ 22536 on insulin secretion and underlying mechanisms. Methods Patch-clamp recording, Ca2+ fluorescence imaging and radioimmunoassay were used to measure outward K+ currents, action potentials (APs), intracellular Ca2+ ([Ca2+]i) and insulin secretion from rat pancreatic beta cells. Results MDL-12,330A (10 µmol/l) potentiated insulin secretion to 1.7 times of control in the presence of 8.3 mmol/l glucose, while SQ 22536 did not show significant effect on insulin secretion. MDL-12,330A prolonged AP durations (APDs) by inhibiting voltage-dependent K+ (KV) channels, leading to an increase in [Ca2+]i levels. It appeared that these effects induced by MDL-12,330A did not result from AC inhibition, since SQ 22536 did not show such effects. Furthermore, inhibition of the downstream effectors of AC/cAMP signaling by PKA inhibitor H89 and Epac inhibitor ESI-09, did not affect KV channels and insulin secretion. Conclusion The putative AC inhibitor MDL-12,330A enhances [Ca2+]i and insulin secretion via inhibition of KV channels rather than AC antagonism in beta cells, suggesting that the non-specific effects is needed to be considered for the right interpretation of the experimental results using this agent in the analyses of the role of AC in cell function.
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Affiliation(s)
- Xiaodong Li
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Jingying Gao
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Jing Yang
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Wan Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yueqin Liang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Dongmei Wu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yunfeng Liu
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
- * E-mail: (YL); (YZ)
| | - Jianping Weng
- Department of Endocrinology, the Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Qingshan Li
- School of Pharmaceutical Sciences, Shanxi Medical University, Taiyuan, China
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- * E-mail: (YL); (YZ)
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Yao XG, Chen F, Li P, Quan L, Chen J, Yu L, Ding H, Li C, Chen L, Gao Z, Wan P, Hu L, Jiang H, Shen X. Natural product vindoline stimulates insulin secretion and efficiently ameliorates glucose homeostasis in diabetic murine models. JOURNAL OF ETHNOPHARMACOLOGY 2013; 150:285-297. [PMID: 24012527 DOI: 10.1016/j.jep.2013.08.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 08/27/2013] [Accepted: 08/27/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Catharanthus roseus (L). Don (Catharanthus roseus) is a traditional anti-diabetic herb widely used in many countries, and the alkaloids of Catharanthus roseus are considered to possess hypoglycemic ability. AIM OF THE STUDY To systematically investigate the potential anti-diabetic effects and the underlying anti-diabetic mechanisms of vindoline, one of the alkaloids in Catharanthus roseus. MATERIALS AND METHODS The regulation of vindoline against the glucose-stimulated insulin secretion (GSIS) was examined in insulinoma MIN6 cells and primary pancreatic islets. Insulin concentration was detected by Elisa assay. Diabetic models of db/db mice and type 2 diabetic rats induced by high-fat diet combining with streptozotocin (STZ/HFD-induced type 2 diabetic rats) were used to evaluate the anti-diabetic effect of vindoline in vivo. Daily oral treatment with vindoline (20mg/kg) to diabetic mice/rats for 4 weeks, body weight and blood glucose were determined every week, oral glucose tolerance test (OGTT) was performed after 4 weeks. RESULTS Vindoline enhanced GSIS in both glucose- and dose-dependent manners (EC50 = 50 μM). It was determined that vindoline acted as a Kv2.1 inhibitor able to reduce the voltage-dependent outward potassium currents finally enhancing insulin secretion. It protected β-cells from the cytokines-induced apoptosis following its inhibitory role in Kv2.1. Moreover, vindoline (20mg/kg) treatment significantly improved glucose homeostasis in db/db mice and STZ/HFD-induced type 2 diabetic rats, as reflected by its functions in increasing plasma insulin concentration, protecting the pancreatic β-cells from damage, decreasing fasting blood glucose and glycated hemoglobin (HbA1c), improving OGTT and reducing plasma triglyceride (TG). CONCLUSION Our findings suggested that vindoline might contribute to the anti-diabetic effects of Catharanthus roseus, and this natural product may find its more applications in the improvement of β-cell dysfunction and further the potential treatment of type 2 diabetes.
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Affiliation(s)
- Xin-gang Yao
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
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