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Paul A, Chumbale SS, Lakra A, Kumar V, Alhat DS, Singh S. Insights into Leishmania donovani potassium channel family and their biological functions. 3 Biotech 2023; 13:266. [PMID: 37425093 PMCID: PMC10326225 DOI: 10.1007/s13205-023-03692-y] [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: 09/27/2022] [Accepted: 06/26/2023] [Indexed: 07/11/2023] Open
Abstract
Leishmania donovani is the causative organism for visceral leishmaniasis. Although this parasite was discovered over a century ago, nothing is known about role of potassium channels in L. donovani. Potassium channels are known for their crucial roles in cellular functions in other organisms. Recently the presence of a calcium-activated potassium channel in L. donovani was reported which prompted us to look for other proteins which could be potassium channels and to investigate their possible physiological roles. Twenty sequences were identified in L. donovani genome and subjected to estimation of physio-chemical properties, motif analysis, localization prediction and transmembrane domain analysis. Structural predictions were also done. The channels were majorly α-helical and predominantly localized in cell membrane and lysosomes. The signature selectivity filter of potassium channel was present in all the sequences. In addition to the conventional potassium channel activity, they were associated with gene ontology terms for mitotic cell cycle, cell death, modulation by virus of host process, cell motility etc. The entire study indicates the presence of potassium channel families in L. donovani which may have involvement in several cellular pathways. Further investigations on these putative potassium channels are needed to elucidate their roles in Leishmania. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03692-y.
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Affiliation(s)
- Anindita Paul
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Shubham Sunil Chumbale
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Anjana Lakra
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Vijay Kumar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Dhanashri Sudam Alhat
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
| | - Sushma Singh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, SAS Nagar, Mohali, 160062 Punjab India
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McClenaghan C, Mukadam MA, Roeglin J, Tryon RC, Grabner M, Dayal A, Meyer GA, Nichols CG. Skeletal muscle delimited myopathy and verapamil toxicity in SUR2 mutant mouse models of AIMS. EMBO Mol Med 2023; 15:e16883. [PMID: 37154692 PMCID: PMC10245035 DOI: 10.15252/emmm.202216883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
ABCC9-related intellectual disability and myopathy syndrome (AIMS) arises from loss-of-function (LoF) mutations in the ABCC9 gene, which encodes the SUR2 subunit of ATP-sensitive potassium (KATP ) channels. KATP channels are found throughout the cardiovascular system and skeletal muscle and couple cellular metabolism to excitability. AIMS individuals show fatigability, muscle spasms, and cardiac dysfunction. We found reduced exercise performance in mouse models of AIMS harboring premature stop codons in ABCC9. Given the roles of KATP channels in all muscles, we sought to determine how myopathy arises using tissue-selective suppression of KATP and found that LoF in skeletal muscle, specifically, underlies myopathy. In isolated muscle, SUR2 LoF results in abnormal generation of unstimulated forces, potentially explaining painful spasms in AIMS. We sought to determine whether excessive Ca2+ influx through CaV 1.1 channels was responsible for myopathology but found that the Ca2+ channel blocker verapamil unexpectedly resulted in premature death of AIMS mice and that rendering CaV 1.1 channels nonpermeable by mutation failed to reverse pathology; results which caution against the use of calcium channel blockers in AIMS.
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Affiliation(s)
- Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical SchoolRutgers UniversityPiscatawayNJUSA
| | - Maya A Mukadam
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Jacob Roeglin
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Robert C Tryon
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Manfred Grabner
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Anamika Dayal
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Gretchen A Meyer
- Program in Physical Therapy, Departments of Orthopaedic Surgery, Neurology and Biomedical EngineeringWashington University School of MedicineSt. LouisMOUSA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
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Tomlinson B, Patil NG, Fok M, Chan P, Lam CWK. The role of sulfonylureas in the treatment of type 2 diabetes. Expert Opin Pharmacother 2021; 23:387-403. [PMID: 34758676 DOI: 10.1080/14656566.2021.1999413] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Type 2 diabetes (T2D) is increasingly prevalent and associated with increased risk for cardiovascular and renal disease. After lifestyle modification, metformin is usually the first-line pharmacotherapy and sulfonylureas are traditionally added after metformin failure. However, with newer glucose lowering drugs that may have less risk of hypoglycemia or that may reduce cardiovascular and renal events, the position of sulfonylureas is being reevaluated. AREAS COVERED In this article, the authors review relevant publications related to the use of sulfonylureas. EXPERT OPINION Sulfonylureas are potent glucose lowering drugs. The risk of hypoglycemia varies with different drugs within the class and can be minimized by using the safer drugs, possibly in lower doses. Cardiovascular events do not appear to be increased with some of the newer generation drugs. The durability of glycemic control also appears comparable to other newer agents. Sulfonylureas are the preferred treatment for some types of monogenic diabetes and selection of T2D patients who may have greater benefit from sulfonylureas based on certain phenotypes and genotypes is likely to be refined further by precision medicine. Sulfonylureas are inexpensive and readily available everywhere and they are still the most frequently used second-line treatment for T2D in many parts of the world.
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Affiliation(s)
- Brian Tomlinson
- Faculty of Medicine, Macau University of Science and Technology, Macau, China
| | | | - Manson Fok
- Faculty of Medicine, Macau University of Science and Technology, Macau, China
| | - Paul Chan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei City, Taiwan
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Rahmani J, Parastouei K, Taghdir M, Santos HO, Hosseini Balam F, Saberi Isfeedvajani M. Healthy Eating Index-2015 and Dietary Total Antioxidant Capacity as Predictors of Prediabetes: A Case-Control Study. Int J Endocrinol 2021; 2021:2742103. [PMID: 34335743 PMCID: PMC8318758 DOI: 10.1155/2021/2742103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The overall dietary quality, as well as the dietary total antioxidant capacity (DTAC), deserves central attention in the management of borderline high glucose levels since nonpharmacological strategies are imperative in this regard. Thus, we aimed to investigate the association between prediabetes with dietary quality and DTAC. METHODS A case-control study was conducted on 49 patients with prediabetes and 98 controls. Demographics, anthropometric measures, and fasting blood glucose levels of all participants were obtained. Participants completed a validated 80-item food frequency questionnaire (FFQ). DTAC scores were generated using FFQ data, and Healthy Eating Index-2015 (HEI-2015) was used as a diet quality index. The lowest tertile of HEI-2015 and DTAC was considered as the reference category, and logistic regression was used to estimate the relationship between prediabetes with HEI-215 and DTAC. RESULTS Mean age and body mass index of participants were 47.42 ± 15.98 years and 27.90 ± 4.96 kg/m2. Patients with prediabetes had lower DTAC scores when compared to controls (11.86 ± 5.77 and 17.81 ± 12.08, P = 0.01). There was a significant inverse association between the highest tertile of the DTAC score when compared with the lowest tertile in crude (OR = 0.11; 95% CI: 0.03-0.43), age-adjusted (OR = 0.13; 95% CI: 0.03-0.48), and fully adjusted (OR = 0.09; 95% CI: 0.02-0.53) models. In contrast, there was no difference between HEI-2015 in patients with prediabetes when compared to controls (74.41 ± 8.91 and 74.41 ± 9.35, respectively; P = 0.85). Correspondingly, no difference was observed between the highest tertile of the HEI-2015 score when compared with the lowest tertile in crude (OR = 1.23; 95% CI: 0.53-2.86), age-adjusted (OR = 1.17; 95% CI: 0.48-2.82), and fully adjusted (OR = 1.53; 95% CI: 0.56-4.16) models. CONCLUSION This study demonstrates a clear association between prediabetes with less DTAC, but not with HEI-2015.
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Affiliation(s)
- Jamal Rahmani
- Health Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Karim Parastouei
- Health Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Maryam Taghdir
- Health Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Heitor O. Santos
- School of Medicine, Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil
| | - Farinaz Hosseini Balam
- Department of Cellular and Molecular Nutrition, School of Nutrition Sciences & Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohsen Saberi Isfeedvajani
- Medicine, Quran and Hadith Research Center & Department of Community Medicine, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Pires Mendes C, Postal BG, Silva Frederico MJ, Gonçalves Marques Elias R, Aiceles de Medeiros Pinto V, da Fonte Ramos C, Devantier Neuenfeldt P, Nunes RJ, Mena Barreto Silva FR. Synthesis of a novel glibenclamide-pioglitazone hybrid compound and its effects on glucose homeostasis in normal and insulin-resistant rats. Bioorg Chem 2021; 114:105157. [PMID: 34328855 DOI: 10.1016/j.bioorg.2021.105157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/19/2021] [Accepted: 07/05/2021] [Indexed: 12/30/2022]
Abstract
A new library of hybrid compounds that combine the functional parts of glibenclamide and pioglitazone was designed and developed. Compounds were screened for their antihyperglycemic effects on the glucose tolerance curve. This approach provided a single molecule that optimizes the pharmacological activities of two drugs used for the treatment of diabetes mellitus type 2 (DM2) and that have distinct biological activities, potentially minimizing the adverse effects of the original drugs. From a total of 15 compounds, 7 were evaluated in vivo; the compound 2; 4- [2- (2-phenyl-4-oxo-1,3-thiazolidin-3-yl) ethyl] benzene-1-sulfonamide (PTEBS) was selected to study its mechanism of action on glucose and lipid homeostasis in acute and chronic animal models related to DM2. PTEBS reduced glycemia and increased serum insulin in hyperglycemic rats, and elevated in vitro insulin production from isolated pancreatic islets. This compound increased the glycogen content in hepatic and muscular tissue. Moreover, PTEBS stimulated the uptake of glucose in soleus muscle through a signaling pathway similar to that of insulin, stimulating translocation and protein synthesis of glucose transporter 4 (GLUT4). PTEBS was effective in increasing insulin sensitivity in resistance rats by stimulating increased muscle glucose uptake, among other mechanisms. In addition, this compound reduced total triglycerides in a tolerance test to lipids and reduced advanced glycation end products (AGES), without altering lactate dehydrogenase (LDH) activity. Thus, we suggest that PTEBS may have similar effects to the respective prototypes, which may improve the therapeutic efficacy of these molecules and decrease adverse effects in the long-term.
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Affiliation(s)
- Camila Pires Mendes
- Universidade Federal de Santa Catarina, Departamento de Bioquímica - Centro de Ciências Biológicas, Campus Universitário, Trindade, CEP: 88040-900 - Florianópolis, SC, Brazil
| | - Bárbara Graziela Postal
- Universidade Federal de Santa Catarina, Departamento de Bioquímica - Centro de Ciências Biológicas, Campus Universitário, Trindade, CEP: 88040-900 - Florianópolis, SC, Brazil
| | - Marisa Jádna Silva Frederico
- Universidade Federal de Santa Catarina, Departamento de Bioquímica - Centro de Ciências Biológicas, Campus Universitário, Trindade, CEP: 88040-900 - Florianópolis, SC, Brazil; Universidade Federal do Ceará, Departamento de Farmacologia e Fisiologia, Faculdade de Medicina, Núcleo de Pesquisa e Desenvolvimento de Medicamentos, Rua Coronel Nunes de Melo, 1000 - Rodolfo Teófilo, Fortaleza, CE 60430-275, Brazil
| | - Rui Gonçalves Marques Elias
- Universidade Federal de Santa Catarina, Departamento de Bioquímica - Centro de Ciências Biológicas, Campus Universitário, Trindade, CEP: 88040-900 - Florianópolis, SC, Brazil; Universidade Estadual do Norte do Paraná - Centro de Ciências da Saúde, Jacarezinho, PR, Brazil
| | | | | | - Patrícia Devantier Neuenfeldt
- Universidade Federal de Santa Catarina, Departamento de Química, Centro de Ciências Físicas e Matemáticas, Campus Universitário, Trindade, CEP: 88040-900, Florianópolis, SC, Brazil; Instituto Federal Catarinense, IFC, Campus São Francisco do Sul, SC, Brazil
| | - Ricardo José Nunes
- Universidade Federal de Santa Catarina, Departamento de Química, Centro de Ciências Físicas e Matemáticas, Campus Universitário, Trindade, CEP: 88040-900, Florianópolis, SC, Brazil
| | - Fátima Regina Mena Barreto Silva
- Universidade Federal de Santa Catarina, Departamento de Bioquímica - Centro de Ciências Biológicas, Campus Universitário, Trindade, CEP: 88040-900 - Florianópolis, SC, Brazil.
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Structure based analysis of K ATP channel with a DEND syndrome mutation in murine skeletal muscle. Sci Rep 2021; 11:6668. [PMID: 33758250 PMCID: PMC7988048 DOI: 10.1038/s41598-021-86121-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome, the most severe end of neonatal diabetes mellitus, is caused by mutation in the ATP-sensitive potassium (KATP) channel. In addition to diabetes, DEND patients present muscle weakness as one of the symptoms, and although the muscle weakness is considered to originate in the brain, the pathological effects of mutated KATP channels in skeletal muscle remain elusive. Here, we describe the local effects of the KATP channel on muscle by expressing the mutation present in the KATP channels of the DEND syndrome in the murine skeletal muscle cell line C2C12 in combination with computer simulation. The present study revealed that the DEND mutation can lead to a hyperpolarized state of the muscle cell membrane, and molecular dynamics simulations based on a recently reported high-resolution structure provide an explanation as to why the mutation reduces ATP sensitivity and reveal the changes in the local interactions between ATP molecules and the channel.
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Umehara T, Tsujita N, Goto M, Tonai S, Nakanishi T, Yamashita Y, Shimada M. Methyl-beta cyclodextrin and creatine work synergistically under hypoxic conditions to improve the fertilization ability of boar ejaculated sperm. Anim Sci J 2021; 91:e13493. [PMID: 33314533 DOI: 10.1111/asj.13493] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 01/06/2023]
Abstract
Although successful fertilization is completed by only 150 sperm in the pig oviduct, more than 50,000 sperms are required to achieve a fertilization rate of more than 70% by pig in vitro fertilization (IVF). In this study, to improve the efficiency of pig IVF, the effects of hypoxic conditions and treatment with creatine and methyl-beta cyclodextrin (MβCD) on the glycolytic pathway were investigated. Under low O2 conditions, zig-zag motility was strongly induced within 30 min; however, the induction disappeared at 60 min. Although caffeine suppressed zig-zag motility under low O2 conditions, creatine induced and sustained zig-zag motility until 120 min. Additionally, pretreatment with MβCD for 15 min greatly enhanced zig-zag motility via ATP production in sperm incubated with creatine under low O2 conditions. Sperm pretreated with MβCD were used for IVF in medium containing creatine under low O2 conditions. A fertilization rate of approximately 70% was achieved with only 1.0 x 104 sperms/mL, and there were few polyspermic embryos. Therefore, our novel method was beneficial for efficient production of pig embryos in vitro. Moreover, the zig-zag motility may be a novel movement which boar capacitated sperm exhibit in the culture medium.
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Affiliation(s)
- Takashi Umehara
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Natsumi Tsujita
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Masaaki Goto
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan.,Livestock Research Institute, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita, Japan
| | - Shingo Tonai
- Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Shobara, Japan
| | - Tomoya Nakanishi
- Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Shobara, Japan
| | - Yasuhisa Yamashita
- Graduate School of Comprehensive Scientific Research, Prefectural University of Hiroshima, Shobara, Japan
| | - Masayuki Shimada
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
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Metabolic Effects of Selective Deletion of Group VIA Phospholipase A 2 from Macrophages or Pancreatic Islet Beta-Cells. Biomolecules 2020; 10:biom10101455. [PMID: 33080873 PMCID: PMC7602969 DOI: 10.3390/biom10101455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022] Open
Abstract
To examine the role of group VIA phospholipase A2 (iPLA2β) in specific cell lineages in insulin secretion and insulin action, we prepared mice with a selective iPLA2β deficiency in cells of myelomonocytic lineage, including macrophages (MØ-iPLA2β-KO), or in insulin-secreting β-cells (β-Cell-iPLA2β-KO), respectively. MØ-iPLA2β-KO mice exhibited normal glucose tolerance when fed standard chow and better glucose tolerance than floxed-iPLA2β control mice after consuming a high-fat diet (HFD). MØ-iPLA2β-KO mice exhibited normal glucose-stimulated insulin secretion (GSIS) in vivo and from isolated islets ex vivo compared to controls. Male MØ-iPLA2β-KO mice exhibited enhanced insulin responsivity vs. controls after a prolonged HFD. In contrast, β-cell-iPLA2β-KO mice exhibited impaired glucose tolerance when fed standard chow, and glucose tolerance deteriorated further when introduced to a HFD. β-Cell-iPLA2β-KO mice exhibited impaired GSIS in vivo and from isolated islets ex vivo vs. controls. β-Cell-iPLA2β-KO mice also exhibited an enhanced insulin responsivity compared to controls. These findings suggest that MØ iPLA2β participates in HFD-induced deterioration in glucose tolerance and that this mainly reflects an effect on insulin responsivity rather than on insulin secretion. In contrast, β-cell iPLA2β plays a role in GSIS and also appears to confer some protection against deterioration in β-cell functions induced by a HFD.
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Kuo YY, Lin JK, Lin YT, Chen JC, Kuo YM, Chen PS, Wu SN, Chen PC. Glibenclamide restores dopaminergic reward circuitry in obese mice through interscauplar brown adipose tissue. Psychoneuroendocrinology 2020; 118:104712. [PMID: 32479969 DOI: 10.1016/j.psyneuen.2020.104712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/29/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Obesity, a critical feature in metabolic disorders, is associated with medical depression. Recent evidence reveals that brown adipose tissue (BAT) activity may contribute to mood disorders, Adenosine triphosphate (ATP)-sensitive K+ (KATP) channels regulate BAT sympathetic nerve activity. However, the mechanism through which BAT activity affects mood control remains unknown. We hypothesized the BAT is involved in depressive-like symptoms regulation by trafficking KATP channels. METHODS Eight-week-old male B6 mice fed with a high-fat diet (HFD) for 12 weeks exhibited characteristics of metabolic disorders, including hyperglycemia, hyperinsulinemia, and hyperlipidemia, as well as depressive symptoms. In this study, we surgically removed interscapular BAT in mice, and these mice exhibited immobility in the forced swim test and less preference for sugar water compared with other mice. To delineate the role of KATP channels in BAT activity regulation, we implanted a miniosmotic pump containing glibenclamide (GB), a KATP channel blocker, into the interscapular BAT of HFD-fed mice. RESULTS GB infusion improved glucose homeostasis, insulin sensitivity, and depressive-like symptoms. KATP channel expression was lower in HFD-fed mice than in chow-fed mice. Notably, GB infusion in HFD-fed mice restored KATP channel expression. CONCLUSION KATP channels are functionally expressed in BAT, and inhibiting BAT-KATP channels improves metabolic syndromes and reduces depressive symptoms through beta-3-adrenergic receptor-mediated protein kinase A signaling.
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Affiliation(s)
- Yi-Ying Kuo
- Department of Physiology, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | | | - Ya-Tin Lin
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan
| | - Jin-Chung Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan
| | - Yu-Ming Kuo
- Department of Cell Biology and Anatomy, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Po-See Chen
- Department of Psychiatry, National Cheng Kung University Hospital, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Pei-Chun Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan.
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Smeland MF, McClenaghan C, Roessler HI, Savelberg S, Hansen GÅM, Hjellnes H, Arntzen KA, Müller KI, Dybesland AR, Harter T, Sala-Rabanal M, Emfinger CH, Huang Y, Singareddy SS, Gunn J, Wozniak DF, Kovacs A, Massink M, Tessadori F, Kamel SM, Bakkers J, Remedi MS, Van Ghelue M, Nichols CG, van Haaften G. ABCC9-related Intellectual disability Myopathy Syndrome is a K ATP channelopathy with loss-of-function mutations in ABCC9. Nat Commun 2019; 10:4457. [PMID: 31575858 PMCID: PMC6773855 DOI: 10.1038/s41467-019-12428-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 08/30/2019] [Indexed: 11/30/2022] Open
Abstract
Mutations in genes encoding KATP channel subunits have been reported for pancreatic disorders and Cantú syndrome. Here, we report a syndrome in six patients from two families with a consistent phenotype of mild intellectual disability, similar facies, myopathy, and cerebral white matter hyperintensities, with cardiac systolic dysfunction present in the two oldest patients. Patients are homozygous for a splice-site mutation in ABCC9 (c.1320 + 1 G > A), which encodes the sulfonylurea receptor 2 (SUR2) subunit of KATP channels. This mutation results in an in-frame deletion of exon 8, which results in non-functional KATP channels in recombinant assays. SUR2 loss-of-function causes fatigability and cardiac dysfunction in mice, and reduced activity, cardiac dysfunction and ventricular enlargement in zebrafish. We term this channelopathy resulting from loss-of-function of SUR2-containing KATP channels ABCC9-related Intellectual disability Myopathy Syndrome (AIMS). The phenotype differs from Cantú syndrome, which is caused by gain-of-function ABCC9 mutations, reflecting the opposing consequences of KATP loss- versus gain-of-function.
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Affiliation(s)
- Marie F Smeland
- Department of Medical Genetics, University Hospital of North Norway, 9019, Tromsø, Norway.
| | - Conor McClenaghan
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
| | - Helen I Roessler
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands
| | - Sanne Savelberg
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands
| | | | - Helene Hjellnes
- Department of Medical Genetics, University Hospital of North Norway, 9019, Tromsø, Norway
| | - Kjell Arne Arntzen
- Department of Neurology, University Hospital of North Norway, 9019, Tromsø, Norway
- Department of Clinical Medicine, UiT-The Arctic University of Norway, 9019, Tromsø, Norway
- The National Neuromuscular Centre of Norway, University Hospital of North Norway, 9019, Tromsø, Norway
| | - Kai Ivar Müller
- Department of Neurology, University Hospital of North Norway, 9019, Tromsø, Norway
- Department of Clinical Medicine, UiT-The Arctic University of Norway, 9019, Tromsø, Norway
| | - Andreas Rosenberger Dybesland
- The National Neuromuscular Centre of Norway, University Hospital of North Norway, 9019, Tromsø, Norway
- Department of Physiotherapy, University Hospital of North Norway, 9019, Tromsø, Norway
| | - Theresa Harter
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
| | - Monica Sala-Rabanal
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University, St Louis, MO, 63110, USA
| | - Chris H Emfinger
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
| | - Yan Huang
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Soma S Singareddy
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
| | - Jamie Gunn
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - David F Wozniak
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Attila Kovacs
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Maarten Massink
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands
| | - Federico Tessadori
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands
- Hubrecht Institute-KNAW and UMC Utrecht, 3584 CT, Utrecht, the Netherlands
| | - Sarah M Kamel
- Hubrecht Institute-KNAW and UMC Utrecht, 3584 CT, Utrecht, the Netherlands
| | - Jeroen Bakkers
- Hubrecht Institute-KNAW and UMC Utrecht, 3584 CT, Utrecht, the Netherlands
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands
| | - Maria S Remedi
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University, St Louis, MO, 63110, USA
| | - Marijke Van Ghelue
- Department of Medical Genetics, University Hospital of North Norway, 9019, Tromsø, Norway
- Department of Medical Genetics, the Arctic University of Norway, 9019, Tromsø, Norway
| | - Colin G Nichols
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO, 63110, USA
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, 3584 CX, Utrecht, the Netherlands.
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11
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Zhou X, Xu C, Zou Z, Shen X, Xie T, Zhang R, Liao L, Dong J. aThe characteristics of glucose metabolism in the sulfonylurea receptor 1 knockout rat model. Mol Med 2019; 25:2. [PMID: 30616503 PMCID: PMC6322298 DOI: 10.1186/s10020-018-0067-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 12/11/2018] [Indexed: 12/26/2022] Open
Abstract
Background Sulfonylurea receptor 1 (SUR1) is primarily responsible for glucose regulation in normal conditions. Here, we sought to investigate the glucose metabolism characteristics of SUR1−/− rats. Methods The TALEN technique was used to construct a SUR1 gene deficiency rat model. Rats were grouped by SUR1 gene knockout or not and sex difference. Body weight; glucose metabolism indicators, including IPGTT, IPITT, glycogen contents and so on; and other molecule changes were examined. Results Insulin secretion was significantly inhibited by knocking out the SUR1 gene. SUR1−/− rats showed lower body weights compared to wild-type rats, and even SUR1−/− males weighed less than wild-type females. Upon SUR1 gene knockout, the rats showed a peculiar plasma glucose profile. During IPGTT, plasma glucose levels were significantly elevated in SUR1−/− rats at 15 min, which could be explained by SUR1 mainly working in the first phase of insulin secretion. Moreover, SUR1−/− male rats showed obviously impaired glucose tolerance than before and a better insulin sensitivity in the 12th week compared with females, which might be related with excess androgen secretion in adulthood. Increased glycogen content and GLUT4 expression and the inactivation of GSK3 were also observed in SUR1−/− rats, which suggested an enhancement of insulin sensitivity. Conclusions These results reconfirm the role of SUR1 in systemic glucose metabolism. More importantly, our SUR1−/− rat model might be applied in other fields, such as for exploring other hypoglycaemic functions of sulfonylureas. Electronic supplementary material The online version of this article (10.1186/s10020-018-0067-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaojun Zhou
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, 250014, People's Republic of China
| | - Chunmei Xu
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, 250014, People's Republic of China
| | - Zhiwei Zou
- Department of Endocrinology, Qilu Hospital of Shandong University, Shandong University, Jinan, Shandong, 250012, People's Republic of China
| | - Xue Shen
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Tianyue Xie
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, China
| | - Rui Zhang
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, 250014, People's Republic of China
| | - Lin Liao
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, 250014, People's Republic of China.
| | - Jianjun Dong
- Department of Endocrinology, Qilu Hospital of Shandong University, Shandong University, Jinan, Shandong, 250012, People's Republic of China.
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12
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Yahaya TO, Salisu TF. A Review of Type 2 Diabetes Mellitus Predisposing Genes. Curr Diabetes Rev 2019; 16:52-61. [PMID: 30514191 DOI: 10.2174/1573399815666181204145806] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 11/22/2018] [Accepted: 11/28/2018] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Scientists are considering the possibility of treating diabetes mellitus (DM) using a personalized approach in which various forms of the diseases will be treated based on the causal gene and its pathogenesis. To this end, scientists have identified mutations in certain genes as probable causes of Type 2 diabetes mellitus (T2DM) with diverse mechanisms. AIM This review was aimed at articulating already identified T2DM genes with their mechanisms of action and phenotypic presentations for the awareness of all stakeholders. METHOD The Google search engine was used to retrieve relevant information on the subject from reliable academic databases such as PubMed, Medline, and Google Scholar, among others. RESULTS At least seventy (70) genes are currently being suspected in the biogenesis of T2DM. However, mutations in, or variants of KCNJ11, PPARG, HNF1B and WFS1 genes, are the most suspected and reported in the pathogenesis of the disease. Mutations in these genes can cause disruption of insulin biosynthesis through the destruction of pancreatic beta cells, change of beta cell morphology, destruction of insulin receptors, among others. These cellular events may lead to insulin resistance and hyperglycemia and, along with environmental triggers such as obesity and overweight, culminate in T2DM. It was observed that each identified gene has its distinct mechanism by which it interacts with other genes and environmental factors to cause T2DM. CONCLUSION Healthcare providers are advised to formulate T2DM drugs or treatment by targeting the causal genes along with their mechanisms.
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Affiliation(s)
- Tajudeen O Yahaya
- Department of Biology, Federal University Birnin Kebbi, Kebbi State, Nigeria
| | - Titilola F Salisu
- Department of Cell Biology and Genetics, University of Lagos, Lagos, Nigeria
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13
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Tinker A, Aziz Q, Li Y, Specterman M. ATP‐Sensitive Potassium Channels and Their Physiological and Pathophysiological Roles. Compr Physiol 2018; 8:1463-1511. [DOI: 10.1002/cphy.c170048] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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14
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Frederico MJS, Castro AJG, Pinto VAM, Ramos CDF, Monteiro FBF, Mascarello A, Nunes RJ, Silva FRMB. Mechanism of action of camphoryl-benzene sulfonamide derivative on glucose uptake in adipose tissue. J Cell Biochem 2018; 119:4408-4419. [PMID: 29130561 DOI: 10.1002/jcb.26506] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/09/2017] [Indexed: 11/09/2022]
Abstract
The aim of the present study was to investigate the mechanism of action of a sulfonamide derivative on glucose uptake in adipose tissue, as well as to characterize the effects of this compound on intestinal disaccharidases and advanced glycation end-products (AGEs) formation. Camphoryl-benzene sulfonamide (CS) was able to stimulate glucose uptake in isolated adipocytes, adipose tissue, and in soleus muscle. The stimulatory effect of the compound (10 μM) on glucose uptake on adipose tissue was blocked by diazoxide, wortmannin, U73122, colchicine, and N-ethylmaleimide. On the other hand, the effects of CS were not blocked by glibenclamide, an inhibitor of the K+ -ATP channel, or even by the inhibitor of protein p38 MAPK, SB 203580. In vivo, this compound reduced intestinal disaccharidase activity, while, in vitro, CS reduced the formation of AGEs at 7, 14, and 28 days of incubation. The stimulatory effect of CS on glucose uptake requires the activation of the K+ -ATP channel, translocation, and fusion of GLUT4 vesicles to the plasma membrane on adipocytes for glucose homeostasis. In addition, the inhibition of disaccharidase activity contributes to the glucose homeostasis in a short-term as well as the remarkable reduction in AGE formation indicates that the CS may prevent of complications of late diabetes.
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Affiliation(s)
- Marisa J S Frederico
- Departamento de Bioquímica-Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Allisson J G Castro
- Departamento de Bioquímica-Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Veronica A M Pinto
- Departamento de Anatomia, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cristiane D F Ramos
- Departamento de Anatomia, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabíola B F Monteiro
- Departamento de Análises Clínicas-Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Brazil
| | - Alessandra Mascarello
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Campus Universitário, Bairro Trindade, Florianópolis, Santa Catarina, Brazil
| | - Ricardo J Nunes
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Campus Universitário, Bairro Trindade, Florianópolis, Santa Catarina, Brazil
| | - Fátima R M B Silva
- Departamento de Bioquímica-Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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15
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Yang CT, Chen L, Xu S, Day JJ, Li X, Xian M. Recent Development of Hydrogen Sulfide Releasing/Stimulating Reagents and Their Potential Applications in Cancer and Glycometabolic Disorders. Front Pharmacol 2017; 8:664. [PMID: 29018341 PMCID: PMC5623001 DOI: 10.3389/fphar.2017.00664] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 09/06/2017] [Indexed: 12/24/2022] Open
Abstract
As an important endogenous gaseous signaling molecule, hydrogen sulfide (H2S) exerts various effects in the body. A variety of pathological changes, such as cancer, glycometabolic disorders, and diabetes, are associated with altered endogenous levels of H2S, especially decreased. Therefore, the supplement of H2S is of great significance for the treatment of diseases containing the above pathological changes. At present, many efforts have been made to increase the in vivo levels of H2S by administration of gaseous H2S, simple inorganic sulfide salts, sophisticated synthetic slow-releasing controllable H2S donors or materials, and using H2S stimulating agents. In this article, we reviewed the recent development of H2S releasing/stimulating reagents and their potential applications in two common pathological processes including cancer and glycometabolic disorders.
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Affiliation(s)
- Chun-Tao Yang
- Affiliated Cancer Hospital and Institute, Key Laboratory of Protein Modification and Degradation in School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China.,Department of Chemistry, Washington State University, Pullman, WA, United States
| | - Li Chen
- Affiliated Cancer Hospital and Institute, Key Laboratory of Protein Modification and Degradation in School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Shi Xu
- Department of Chemistry, Washington State University, Pullman, WA, United States
| | - Jacob J Day
- Department of Chemistry, Washington State University, Pullman, WA, United States
| | - Xiang Li
- Affiliated Cancer Hospital and Institute, Key Laboratory of Protein Modification and Degradation in School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
| | - Ming Xian
- Department of Chemistry, Washington State University, Pullman, WA, United States
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16
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Glucose Sensing by Skeletal Myocytes Couples Nutrient Signaling to Systemic Homeostasis. Mol Cell 2017; 66:332-344.e4. [PMID: 28475869 PMCID: PMC5489118 DOI: 10.1016/j.molcel.2017.04.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 02/07/2017] [Accepted: 04/05/2017] [Indexed: 12/21/2022]
Abstract
Skeletal muscle is a major site of postprandial glucose disposal. Inadequate insulin action in skeletal myocytes contributes to hyperglycemia in diabetes. Although glucose is known to stimulate insulin secretion by β cells, whether it directly engages nutrient signaling pathways in skeletal muscle to maintain systemic glucose homeostasis remains largely unexplored. Here we identified the Baf60c-Deptor-AKT pathway as a target of muscle glucose sensing that augments insulin action in skeletal myocytes. Genetic activation of this pathway improved postprandial glucose disposal in mice, whereas its muscle-specific ablation impaired insulin action and led to postprandial glucose intolerance. Mechanistically, glucose triggers KATP channel-dependent calcium signaling, which promotes HDAC5 phosphorylation and nuclear exclusion, leading to Baf60c induction and insulin-independent AKT activation. This pathway is engaged by the anti-diabetic sulfonylurea drugs to exert their full glucose-lowering effects. These findings uncover an unexpected mechanism of glucose sensing in skeletal myocytes that contributes to homeostasis and therapeutic action.
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17
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Youssef N, Campbell S, Barr A, Gandhi M, Hunter B, Dolinsky V, Dyck JRB, Clanachan AS, Light PE. Hearts lacking plasma membrane KATP channels display changes in basal aerobic metabolic substrate preference and AMPK activity. Am J Physiol Heart Circ Physiol 2017; 313:H469-H478. [DOI: 10.1152/ajpheart.00612.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 12/12/2022]
Abstract
Cardiac ATP-sensitive K+ (KATP) channels couple changes in cellular metabolism to membrane excitability and are activated during metabolic stress, although under basal aerobic conditions, KATP channels are thought to be predominately closed. Despite intense research into the roles of KATP channels during metabolic stress, their contribution to aerobic basal cardiac metabolism has not been previously investigated. Hearts from Kir6.2+/+ and Kir6.2−/− mice were perfused in working mode, and rates of glycolysis, fatty acid oxidation, and glucose oxidation were measured. Changes in activation/expression of proteins regulating metabolism were probed by Western blot analysis. Despite cardiac mechanical function and metabolic efficiency being similar in both groups, hearts from Kir6.2−/− mice displayed an approximately twofold increase in fatty acid oxidation and a 0.45-fold reduction in glycolytic rates but similar glucose oxidation rates compared with hearts from Kir6.2+/+ mice. Kir6.2−/− hearts also possessed elevated levels of activated AMP-activated protein kinase (AMPK), higher glycogen content, and reduced mitochondrial density. Moreover, activation of AMPK by isoproterenol or diazoxide was significantly blunted in Kir6.2−/− hearts. These data indicate that KATP channel ablation alters aerobic basal cardiac metabolism. The observed increase in fatty acid oxidation and decreased glycolysis before any metabolic insult may contribute to the poor recovery observed in Kir6.2−/− hearts in response to exercise or ischemia-reperfusion injury. Therefore, KATP channels may play an important role in the regulation of cardiac metabolism through AMPK signaling. NEW & NOTEWORTHY In this study, we show that genetic ablation of plasma membrane ATP-sensitive K+ channels results in pronounced changes in cardiac metabolic substrate preference and AMP-activated protein kinase activity. These results suggest that ATP-sensitive K+ channels may play a novel role in regulating metabolism in addition to their well-documented effects on ionic homeostasis during periods of stress.
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Affiliation(s)
- Nermeen Youssef
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Scott Campbell
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Amy Barr
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Manoj Gandhi
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Beth Hunter
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Vernon Dolinsky
- Children’s Hospital Research Institute of Manitoba, Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jason R. B. Dyck
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; and
| | - Alexander S. Clanachan
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E. Light
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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18
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Scott K, Benkhalti M, Calvert ND, Paquette M, Zhen L, Harper ME, Al-Dirbashi OY, Renaud JM. KATP channel deficiency in mouse FDB causes an impairment of energy metabolism during fatigue. Am J Physiol Cell Physiol 2016; 311:C559-C571. [PMID: 27488667 DOI: 10.1152/ajpcell.00137.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/27/2016] [Indexed: 12/25/2022]
Abstract
The skeletal muscle ATP-sensitive K+ (KATP) channel is crucial in preventing fiber damage and contractile dysfunction, possibly by preventing damaging ATP depletion. The objective of this study was to investigate changes in energy metabolism during fatigue in wild-type and inwardly rectifying K+ channel (Kir6.2)-deficient (Kir6.2-/-) flexor digitorum brevis (FDB), a muscle that lacks functional KATP channels. Fatigue was elicited with one tetanic contraction every second. Decreases in ATP and total adenylate levels were significantly greater in wild-type than Kir6.2-/- FDB during the last 2 min of the fatigue period. Glycogen depletion was greater in Kir6.2-/- FDB for the first 60 s, but not by the end of the fatigue period, while there was no difference in glucose uptake. The total amount of glucosyl units entering glycolysis was the same in wild-type and Kir6.2-/- FDB. During the first 60 s, Kir6.2-/- FDB generated less lactate and more CO2; in the last 120 s, Kir6.2-/- FDB stopped generating CO2 and produced more lactate. The ATP generated during fatigue from phosphocreatine, glycolysis (lactate), and oxidative phosphorylation (CO2) was 3.3-fold greater in Kir6.2-/- than wild-type FDB. Because ATP and total adenylate were significantly less in Kir6.2-/- FDB, it is suggested that Kir6.2-/- FDB has a greater energy deficit, despite a greater ATP production, which is further supported by greater glucose uptake and lactate and CO2 production in Kir6.2-/- FDB during the recovery period. It is thus concluded that a lack of functional KATP channels results in an impairment of energy metabolism.
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Affiliation(s)
- Kyle Scott
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Maria Benkhalti
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicholas D Calvert
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mathieu Paquette
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Li Zhen
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Osama Y Al-Dirbashi
- Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada; and Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada;
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19
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Selvin D, Renaud JM. Changes in myoplasmic Ca2+ during fatigue differ between FDB fibers, between glibenclamide-exposed and Kir6.2-/- fibers and are further modulated by verapamil. Physiol Rep 2015; 3:3/3/e12303. [PMID: 25742954 PMCID: PMC4393149 DOI: 10.14814/phy2.12303] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
One objective of this study was to document how individual FDB muscle fibers depend on the myoprotection of KATP channels during fatigue. Verapamil, a CaV1.1 channel blocker, prevents large increases in unstimulated force during fatigue in KATP-channel-deficient muscles. A second objective was to determine if verapamil reduces unstimulated [Ca(2+)]i in KATP-channel-deficient fibers. We measured changes in myoplasmic [Ca(2+)] ([Ca(2+)]i) using two KATP-channel-deficient models: (1) a pharmacological approach exposing fibers to glibenclamide, a channel blocker, and (2) a genetic approach using fibers from null mice for the Kir6.2 gene. Fatigue was elicited with one tetanic contraction every sec for 3 min. For all conditions, large differences in fatigue kinetics were observed from fibers which had greater tetanic [Ca(2+)]i at the end than at the beginning of fatigue to fibers which eventually completely failed to release Ca(2+) upon stimulation. Compared to control conditions, KATP-channel-deficient fibers had a greater proportion of fiber with large decreases in tetanic [Ca(2+)]i, fade and complete failure to release Ca(2+) upon stimulation. There was, however, a group of KATP-channel-deficient fibers that had similar fatigue kinetics to those of the most fatigue-resistant control fibers. For the first time, differences in fatigue kinetics were observed between Kir6.2(-/-) and glibenclamide-exposed muscle fibers. Verapamil significantly reduced unstimulated and tetanic [Ca(2+)]i. It is concluded that not all fibers are dependent on the myoprotection of KATP channels and that the decrease in unstimulated force by verapamil reported in a previous studies in glibenclamide-exposed fibers is due to a reduction in Ca(2+) load by reducing Ca(2+) influx through CaV1.1 channels between and during contractions.
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Affiliation(s)
- David Selvin
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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20
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Rolim ALR, Lindsey SC, Kunii IS, Crispim F, Moisés RCMS, Maciel RMB, Dias-da-Silva MR. The insulin-sensitivity sulphonylurea receptor variant is associated with thyrotoxic paralysis. J Mol Endocrinol 2014; 53:295-301. [PMID: 25143473 DOI: 10.1530/jme-14-0083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Thyrotoxicosis is the most common cause of the acquired flaccid muscle paralysis in adults called thyrotoxic periodic paralysis (TPP) and is characterised by transient hypokalaemia and hypophosphataemia under high thyroid hormone levels that is frequently precipitated by carbohydrate load. The sulphonylurea receptor 1 (SUR1 (ABCC8)) is an essential regulatory subunit of the β-cell ATP-sensitive K(+) channel that controls insulin secretion after feeding. Additionally, the SUR1 Ala1369Ser variant appears to be associated with insulin sensitivity. We examined the ABCC8 gene at the single nucleotide level using PCR-restriction fragment length polymorphism (RFLP) analysis to determine its allelic variant frequency and calculated the frequency of the Ala1369Ser C-allele variant in a cohort of 36 Brazilian TPP patients in comparison with 32 controls presenting with thyrotoxicosis without paralysis (TWP). We verified that the frequency of the alanine 1369 C-allele was significantly higher in TPP patients than in TWP patients (61.1 vs 34.4%, odds ratio (OR)=3.42, P=0.039) and was significantly more common than the minor allele frequency observed in the general population from the 1000 Genomes database (61.1 vs 29.0%, OR=4.87, P<0.005). Additionally, the C-allele frequency was similar between TWP patients and the general population (34.4 vs 29%, OR=1.42, P=0.325). We have demonstrated that SUR1 alanine 1369 variant is associated with allelic susceptibility to TPP. We suggest that the hyperinsulinaemia that is observed in TPP may be linked to the ATP-sensitive K(+)/SUR1 alanine variant and, therefore, contribute to the major feedforward precipitating factors in the pathophysiology of TPP.
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Affiliation(s)
- Ana Luiza R Rolim
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
| | - Susan C Lindsey
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
| | - Ilda S Kunii
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
| | - Felipe Crispim
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
| | - Regina Célia M S Moisés
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
| | - Rui M B Maciel
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
| | - Magnus R Dias-da-Silva
- Laboratory of Molecular and Translational EndocrinologyDepartment of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Pedro de Toledo, 669, 11° andar, 04039-032 São Paulo, SP, Brazil
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Wang QA, Scherer PE, Gupta RK. Improved methodologies for the study of adipose biology: insights gained and opportunities ahead. J Lipid Res 2014; 55:605-24. [PMID: 24532650 PMCID: PMC3966696 DOI: 10.1194/jlr.r046441] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 02/10/2014] [Indexed: 12/14/2022] Open
Abstract
Adipocyte differentiation and function have become areas of intense focus in the field of energy metabolism; however, understanding the role of specific genes in the establishment and maintenance of fat cell function can be challenging and complex. In this review, we offer practical guidelines for the study of adipocyte development and function. We discuss improved cellular and genetic systems for the study of adipose biology and highlight recent insights gained from these new approaches.
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Affiliation(s)
- Qiong A. Wang
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
| | - Philipp E. Scherer
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75287
| | - Rana K. Gupta
- Department of Internal Medicine, Touchstone Diabetes Center, and University of Texas Southwestern Medical Center, Dallas, TX 75287
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22
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Rufino AT, Rosa SC, Judas F, Mobasheri A, Lopes MC, Mendes AF. Expression and function of K(ATP) channels in normal and osteoarthritic human chondrocytes: possible role in glucose sensing. J Cell Biochem 2013; 114:1879-89. [PMID: 23494827 PMCID: PMC3736163 DOI: 10.1002/jcb.24532] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 02/27/2013] [Indexed: 12/20/2022]
Abstract
ATP-sensitive potassium [K(ATP)] channels sense intracellular ATP/ADP levels, being essential components of a glucose-sensing apparatus in various cells that couples glucose metabolism, intracellular ATP/ADP levels and membrane potential. These channels are present in human chondrocytes, but their subunit composition and functions are unknown. This study aimed at elucidating the subunit composition of K(ATP) channels expressed in human chondrocytes and determining whether they play a role in regulating the abundance of major glucose transporters, GLUT-1 and GLUT-3, and glucose transport capacity. The results obtained show that human chondrocytes express the pore forming subunits, Kir6.1 and Kir6.2, at the mRNA and protein levels and the regulatory sulfonylurea receptor (SUR) subunits, SUR2A and SUR2B, but not SUR1. The expression of these subunits was no affected by culture under hyperglycemia-like conditions. Functional impairment of the channel activity, using a SUR blocker (glibenclamide 10 or 20 nM), reduced the protein levels of GLUT-1 and GLUT-3 by approximately 30% in normal chondrocytes, while in cells from cartilage with increasing osteoarthritic (OA) grade no changes were observed. Glucose transport capacity, however, was not affected in normal or OA chondrocytes. These results show that K(ATP) channel activity regulates the abundance of GLUT-1 and GLUT-3, although other mechanisms are involved in regulating the overall glucose transport capacity of human chondrocytes. Therefore, K(ATP) channels are potential components of a broad glucose sensing apparatus that modulates glucose transporters and allows human chondrocytes to adjust to varying extracellular glucose concentrations. This function of K(ATP) channels seems to be impaired in OA chondrocytes.
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Affiliation(s)
- Ana T Rufino
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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23
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Henquin JC, Nenquin M, Sempoux C, Guiot Y, Bellanné-Chantelot C, Otonkoski T, de Lonlay P, Nihoul-Fékété C, Rahier J. In vitro insulin secretion by pancreatic tissue from infants with diazoxide-resistant congenital hyperinsulinism deviates from model predictions. J Clin Invest 2011; 121:3932-42. [PMID: 21968111 DOI: 10.1172/jci58400] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 07/13/2011] [Indexed: 01/25/2023] Open
Abstract
Congenital hyperinsulinism (CHI) is the major cause of persistent neonatal hypoglycemia. CHI most often occurs due to mutations in the ABCC8 (which encodes sulfonylurea receptor 1) or KCNJ11 (which encodes the potassium channel Kir6.2) gene, which result in a lack of functional KATP channels in pancreatic β cells. Diffuse forms of CHI (DiCHI), in which all β cells are abnormal, often require subtotal pancreatectomy, whereas focal forms (FoCHI), which are characterized by localized hyperplasia of abnormal β cells, can be cured by resection of the lesion. Here, we characterized the in vitro kinetics of insulin secretion by pancreatic fragments from 6 DiCHI patients and by focal lesion and normal adjacent pancreas from 18 FoCHI patients. Responses of normal pancreas were similar to those reported for islets from adult organ donors. Compared with normal pancreas, basal insulin secretion was elevated in both FoCHI and DiCHI tissue. Affected tissues were heterogeneous in their secretory responses, with increased glucose levels often producing a rapid increase in insulin secretion that could be followed by a paradoxical decrease below prestimulatory levels. The KATP channel blocker tolbutamide was consistently ineffective in stimulating insulin secretion; conversely, the KATP channel activator diazoxide often caused an unanticipated increase in insulin secretion. These observed alterations in secretory behavior were similar in focal lesion and DiCHI tissue, and independent of the specific mutation in ABCC8 or KCNJ11. They cannot be explained by classic models of β cell function. Our results provide insight into the excessive and sometimes paradoxical changes in insulin secretion observed in CHI patients with inactivating mutations of KATP channels.
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Affiliation(s)
- Jean-Claude Henquin
- Unit of Endocrinology and Metabolism, Faculty of Medicine, University of Louvain, Brussels, Belgium.
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Quan Y, Barszczyk A, Feng ZP, Sun HS. Current understanding of K ATP channels in neonatal diseases: focus on insulin secretion disorders. Acta Pharmacol Sin 2011; 32:765-80. [PMID: 21602835 PMCID: PMC4009965 DOI: 10.1038/aps.2011.57] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/13/2011] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are cell metabolic sensors that couple cell metabolic status to electric activity, thus regulating many cellular functions. In pancreatic beta cells, K(ATP) channels modulate insulin secretion in response to fluctuations in plasma glucose level, and play an important role in glucose homeostasis. Recent studies show that gain-of-function and loss-of-function mutations in K(ATP) channel subunits cause neonatal diabetes mellitus and congenital hyperinsulinism respectively. These findings lead to significant changes in the diagnosis and treatment for neonatal insulin secretion disorders. This review describes the physiological and pathophysiological functions of K(ATP) channels in glucose homeostasis, their specific roles in neonatal diabetes mellitus and congenital hyperinsulinism, as well as future perspectives of K(ATP) channels in neonatal diseases.
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Affiliation(s)
- Yi Quan
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Andrew Barszczyk
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Zhong-ping Feng
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Hong-shuo Sun
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Surgery, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Pharmacology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
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25
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Park YB, Choi YJ, Park SY, Kim JY, Kim SH, Song DK, Won KC, Kim YW. ATP-Sensitive Potassium Channel-Deficient Mice Show Hyperphagia but Are Resistant to Obesity. Diabetes Metab J 2011; 35:219-25. [PMID: 21785741 PMCID: PMC3138101 DOI: 10.4093/dmj.2011.35.3.219] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 12/22/2010] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND The hypothalamus, the center for body weight regulation, can sense changes in blood glucose level based on ATP-sensitive potassium (K(ATP)) channels in the hypothalamic neurons. We hypothesized that a lack of glucose sensing in the hypothalamus affects the regulations of appetite and body weight. METHODS To evaluate this hypothesis, the responses to glucose loading and high fat feeding for eight weeks were compared in Kir6.2 knock-out (KO) mice and control C57BL/6 mice, because Kir6.2 is a key component of the K(ATP) channel. RESULTS The hypothalamic neuropeptide Y (NPY) analyzed one hour after glucose injection was suppressed in C57BL/6 mice, but not in Kir6.2 KO mice, suggesting a blunted hypothalamic response to glucose in Kir6.2 KO mice. The hypothalamic NPY expression at a fed state was elevated in Kir6.2 KO mice and was accompanied with hyperphagia. However, the retroperitoneal fat mass was markedly decreased in Kir6.2 KO mice compared to that in C57BL/6 mice. Moreover, the body weight and visceral fat following eight weeks of high fat feeding in Kir6.2 KO mice were not significantly different from those in control diet-fed Kir6.2 KO mice, while body weight and visceral fat mass were elevated due to high fat feeding in C57BL/6 mice. CONCLUSION These results suggested that Kir6.2 KO mice showed a blunted hypothalamic response to glucose loading and elevated hypothalamic NPY expression accompanied with hyperphagia, while visceral fat mass was decreased, suggesting resistance to diet-induced obesity. Further study is needed to explain this phenomenon.
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Affiliation(s)
- Yeul Bum Park
- Department of Neurosurgery, Yeungnam University College of Medicine, Daegu, Korea
| | - Yun Jung Choi
- Department of Physiology, Yeungnam University College of Medicine, Daegu, Korea
| | - So Young Park
- Department of Physiology, Yeungnam University College of Medicine, Daegu, Korea
| | - Jong Yeon Kim
- Department of Physiology, Yeungnam University College of Medicine, Daegu, Korea
| | - Seong Ho Kim
- Department of Neurosurgery, Yeungnam University College of Medicine, Daegu, Korea
| | - Dae Kyu Song
- Department of Physiology, Keimyung University College of Medicine, Daegu, Korea
| | - Kyu Chang Won
- Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea
| | - Yong Woon Kim
- Department of Neurosurgery, Yeungnam University College of Medicine, Daegu, Korea
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Lang V, Light PE. The molecular mechanisms and pharmacotherapy of ATP-sensitive potassium channel gene mutations underlying neonatal diabetes. Pharmgenomics Pers Med 2010; 3:145-61. [PMID: 23226049 PMCID: PMC3513215 DOI: 10.2147/pgpm.s6969] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Indexed: 12/14/2022] Open
Abstract
Neonatal diabetes mellitus (NDM) is a monogenic disorder caused by mutations in genes involved in regulation of insulin secretion from pancreatic β-cells. Mutations in the KCNJ11 and ABCC8 genes, encoding the adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channel Kir6.2 and SUR1 subunits, respectively, are found in ∼50% of NDM patients. In the pancreatic β-cell, K(ATP) channel activity couples glucose metabolism to insulin secretion via cellular excitability and mutations in either KCNJ11 or ABCC8 genes alter K(ATP) channel activity, leading to faulty insulin secretion. Inactivation mutations decrease K(ATP) channel activity and stimulate excessive insulin secretion, leading to hyperinsulinism of infancy. In direct contrast, activation mutations increase K(ATP) channel activity, resulting in impaired insulin secretion, NDM, and in severe cases, developmental delay and epilepsy. Many NDM patients with KCNJ11 and ABCC8 mutations can be successfully treated with sulfonylureas (SUs) that inhibit the K(ATP) channel, thus replacing the need for daily insulin injections. There is also strong evidence indicating that SU therapy ameliorates some of the neurological defects observed in patients with more severe forms of NDM. This review focuses on the molecular and cellular mechanisms of mutations in the K(ATP) channel that underlie NDM. SU pharmacogenomics is also discussed with respect to evaluating whether patients with certain K(ATP) channel activation mutations can be successfully switched to SU therapy.
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Affiliation(s)
- Veronica Lang
- Department of Pharmacology and Alberta Diabetes Institute, Faculty of Medicine and Dentistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E Light
- Department of Pharmacology and Alberta Diabetes Institute, Faculty of Medicine and Dentistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada
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27
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Reyes S, Park S, Terzic A, Alekseev AE. K(ATP) channels process nucleotide signals in muscle thermogenic response. Crit Rev Biochem Mol Biol 2010; 45:506-19. [PMID: 20925594 DOI: 10.3109/10409238.2010.513374] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Uniquely gated by intracellular adenine nucleotides, sarcolemmal ATP-sensitive K(+) (K(ATP)) channels have been typically assigned to protective cellular responses under severe energy insults. More recently, K(ATP) channels have been instituted in the continuous control of muscle energy expenditure under non-stressed, physiological states. These advances raised the question of how K(ATP) channels can process trends in cellular energetics within a milieu where each metabolic system is set to buffer nucleotide pools. Unveiling the mechanistic basis of the K(ATP) channel-driven thermogenic response in muscles thus invites the concepts of intracellular compartmentalization of energy and proteins, along with nucleotide signaling over diffusion barriers. Furthermore, it requires gaining insight into the properties of reversibility of intrinsic ATPase activity associated with K(ATP) channel complexes. Notwithstanding the operational paradigm, the homeostatic role of sarcolemmal K(ATP) channels can be now broadened to a wider range of environmental cues affecting metabolic well-being. In this way, under conditions of energy deficit such as ischemic insult or adrenergic stress, the operation of K(ATP) channel complexes would result in protective energy saving, safeguarding muscle performance and integrity. Under energy surplus, downregulation of K(ATP) channel function may find potential implications in conditions of energy imbalance linked to obesity, cold intolerance and associated metabolic disorders.
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Affiliation(s)
- Santiago Reyes
- Marriott Heart Diseases Research Program, Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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28
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Flagg TP, Enkvetchakul D, Koster JC, Nichols CG. Muscle KATP channels: recent insights to energy sensing and myoprotection. Physiol Rev 2010; 90:799-829. [PMID: 20664073 DOI: 10.1152/physrev.00027.2009] [Citation(s) in RCA: 202] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are present in the surface and internal membranes of cardiac, skeletal, and smooth muscle cells and provide a unique feedback between muscle cell metabolism and electrical activity. In so doing, they can play an important role in the control of contractility, particularly when cellular energetics are compromised, protecting the tissue against calcium overload and fiber damage, but the cost of this protection may be enhanced arrhythmic activity. Generated as complexes of Kir6.1 or Kir6.2 pore-forming subunits with regulatory sulfonylurea receptor subunits, SUR1 or SUR2, the differential assembly of K(ATP) channels in different tissues gives rise to tissue-specific physiological and pharmacological regulation, and hence to the tissue-specific pharmacological control of contractility. The last 10 years have provided insights into the regulation and role of muscle K(ATP) channels, in large part driven by studies of mice in which the protein determinants of channel activity have been deleted or modified. As yet, few human diseases have been correlated with altered muscle K(ATP) activity, but genetically modified animals give important insights to likely pathological roles of aberrant channel activity in different muscle types.
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Affiliation(s)
- Thomas P Flagg
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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29
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McTaggart JS, Clark RH, Ashcroft FM. The role of the KATP channel in glucose homeostasis in health and disease: more than meets the islet. J Physiol 2010; 588:3201-9. [PMID: 20519313 DOI: 10.1113/jphysiol.2010.191767] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are critical for the maintenance of glucose homeostasis. They are essential for glucose-stimulated insulin secretion from pancreatic beta-cells, contribute to the mechanisms by which hypoglycaemia stimulates glucagon release from pancreatic alpha-cells, and are involved in glucose uptake into skeletal muscle, glucose production and release from the liver, and feeding behaviour. Not surprisingly, loss- or gain-of-function mutations in K(ATP) channel genes have profound effects, giving rise to congenital hyperinsulinaemia and neonatal diabetes respectively. This symposium review focuses on our current understanding of the role of the K(ATP) channel in glucose homeostasis in health and disease.
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Affiliation(s)
- James S McTaggart
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, and OXION Centre for Ion Channel Studies, Sherrington Building, Parks Road, Oxford OX1 3PT, UK
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30
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Kristensen M, Juel C. Potassium-transporting proteins in skeletal muscle: cellular location and fibre-type differences. Acta Physiol (Oxf) 2010; 198:105-23. [PMID: 19769637 DOI: 10.1111/j.1748-1716.2009.02043.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract Potassium (K(+)) displacement in skeletal muscle may be an important factor in the development of muscle fatigue during intense exercise. It has been shown in vitro that an increase in the extracellular K(+) concentration ([K(+)](e)) to values higher than approx. 10 mm significantly reduce force development in unfatigued skeletal muscle. Several in vivo studies have shown that [K(+)](e) increases progressively with increasing work intensity, reaching values higher than 10 mm. This increase in [K(+)](e) is expected to be even higher in the transverse (T)-tubules than the concentration reached in the interstitium. Besides the voltage-sensitive K(+) (K(v)) channels that generate the action potential (AP) it is suggested that the big-conductance Ca(2+)-dependent K(+) (K(Ca)1.1) channel contributes significantly to the K(+) release into the T-tubules. Also the ATP-dependent K(+) (K(ATP)) channel participates, but is suggested primarily to participate in K(+) release to the interstitium. Because there is restricted diffusion of K(+) to the interstitium, K(+) released to the T-tubules during AP propagation will be removed primarily by reuptake mediated by transport proteins located in the T-tubule membrane. The most important protein that mediates K(+) reuptake in the T-tubules is the Na(+),K(+)-ATPase alpha(2) dimers, but a significant contribution of the strong inward rectifier K(+) (Kir2.1) channel is also suggested. The Na(+), K(+), 2Cl(-) 1 (NKCC1) cotransporter also participates in K(+) reuptake but probably mainly from the interstitium. The relative content of the different K(+)-transporting proteins differs in oxidative and glycolytic muscles, and might explain the different [K(+)](e) tolerance observed.
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Affiliation(s)
- M Kristensen
- Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2200, Copenhagen N, Denmark.
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31
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Kline CF, Hund TJ, Mohler PJ. Ankyrin regulates KATP channel membrane trafficking and gating in excitable cells. Channels (Austin) 2010; 4:55-7. [PMID: 19901534 DOI: 10.4161/chan.4.1.10362] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
K(ATP) channels play critical roles in many cellular functions by coupling cell metabolic status to electrical activity. First discovered in cardiomyocytes,(1) K(ATP) channels (comprised of Kir6.x and SUR subunits) have since been found in many other tissues, including pancreatic beta cells, skeletal muscle, smooth muscle, brain, pituitary and kidney. By linking cellular metabolic state with membrane potential, K(ATP) channels are able to regulate a number of cellular functions such as hormone secretion, vascular tone and excitability. Specifically, a reduction in metabolism causes a decrease in the ATP:ADP ratio, opening of K(ATP) channels, K(+) efflux, membrane hyperpolarization, and suppression of electrical activity. Conversely, increased cellular metabolism causes an increase in the ATP:ADP ratio that leads to closure of the K(ATP) channel, membrane depolarization, and stimulation of cell electrical activity.
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Affiliation(s)
- Crystal F Kline
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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32
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Alekseev AE, Reyes S, Yamada S, Hodgson-Zingman DM, Sattiraju S, Zhu Z, Sierra A, Gerbin M, Coetzee WA, Goldhamer DJ, Terzic A, Zingman LV. Sarcolemmal ATP-sensitive K(+) channels control energy expenditure determining body weight. Cell Metab 2010; 11:58-69. [PMID: 20074528 PMCID: PMC2849280 DOI: 10.1016/j.cmet.2009.11.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 09/15/2009] [Accepted: 11/19/2009] [Indexed: 11/15/2022]
Abstract
Metabolic processes that regulate muscle energy use are major determinants of bodily energy balance. Here, we find that sarcolemmal ATP-sensitive K(+) (K(ATP)) channels, which couple membrane excitability with cellular metabolic pathways, set muscle energy expenditure under physiological stimuli. Disruption of K(ATP) channel function provoked, under conditions of unaltered locomotor activity and blood substrate availability, an extra energy cost of cardiac and skeletal muscle performance. Inefficient fuel metabolism in K(ATP) channel-deficient striated muscles reduced glycogen and fat body depots, promoting a lean phenotype. The propensity to lesser body weight imposed by K(ATP) channel deficit persisted under a high-fat diet, yet obesity restriction was achieved at the cost of compromised physical endurance. Thus, sarcolemmal K(ATP) channels govern muscle energy economy, and their downregulation in a tissue-specific manner could present an antiobesity strategy by rendering muscle increasingly thermogenic at rest and less fuel efficient during exercise.
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Clark R, Proks P. ATP-sensitive potassium channels in health and disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 654:165-92. [PMID: 20217498 DOI: 10.1007/978-90-481-3271-3_8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ATP-sensitive potassium (K(ATP)) channel plays a crucial role in insulin secretion and thus glucose homeostasis. K(ATP) channel activity in the pancreatic beta-cell is finely balanced; increased activity prevents insulin secretion, whereas reduced activity stimulates insulin release. The beta-cell metabolism tightly regulates K(ATP) channel gating, and if this coupling is perturbed, two distinct disease states can result. Diabetes occurs when the K(ATP) channel fails to close in response to increased metabolism, whereas congenital hyperinsulinism results when K(ATP) channels remain closed even at very low blood glucose levels. In general there is a good correlation between the magnitude of K(ATP) current and disease severity. Mutations that cause a complete loss of K(ATP) channels in the beta-cell plasma membrane produce a severe form of congenital hyperinsulinism, whereas mutations that partially impair channel function produce a milder phenotype. Similarly mutations that greatly reduce the ATP sensitivity of the K(ATP) channel lead to a severe form of neonatal diabetes with associated neurological complications, whilst mutations that cause smaller shifts in ATP sensitivity cause neonatal diabetes alone. This chapter reviews our current understanding of the pancreatic beta-cell K(ATP) channel and highlights recent structural, functional and clinical advances.
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Affiliation(s)
- Rebecca Clark
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
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Stoller D, Pytel P, Katz S, Earley JU, Collins K, Metcalfe J, Lang RM, McNally EM. Impaired exercise tolerance and skeletal muscle myopathy in sulfonylurea receptor-2 mutant mice. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1144-53. [PMID: 19675276 DOI: 10.1152/ajpregu.00081.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
By sensing intracellular energy levels, ATP-sensitive potassium (K(ATP)) channels help regulate vascular tone, glucose metabolism, and cardioprotection. SUR2 mutant mice lack full-length K(ATP) channels in striated and smooth muscle and display a complex phenotype of hypertension and coronary vasospasm. SUR2 mutant mice also display baseline cardioprotection and can withstand acute sympathetic stress better than normal mice. We now studied response to a form of chronic stress, namely that induced by 4 wk of daily exercise on SUR2 mutant mice. Control mice increased exercise capacity by 400% over the training period, while SUR2 mutant mice showed little increase in exercise capacity. Unexercised SUR2 mutant showed necrotic and regenerating fibers in multiple muscle skeletal muscles, including quadriceps, tibialis anterior, and diaphragm muscles. Unlike exercised control animals, SUR2 mutant mice did not lose weight, presumably due to less overall exertion. Unexercised SUR2 mutant mice showed a trend of mildly reduced cardiac function, measured by fractional shortening, (46 +/- 4% vs. 57 +/- 7% for SUR2 mutant and control, respectively), and this decrease was not exacerbated by chronic exercise exposure. Despite an improved response to acute sympathetic stress and baseline cardioprotection, exercise intolerance results from lack of SUR2 K(ATP) channels in mice.
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Affiliation(s)
- Douglas Stoller
- Committee on Cellular and Molecular Physiology, The University of Chicago, Chicago, Illinois 60637, USA
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35
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Annicotte JS, Blanchet E, Chavey C, Iankova I, Costes S, Assou S, Teyssier J, Dalle S, Sardet C, Fajas L. The CDK4-pRB-E2F1 pathway controls insulin secretion. Nat Cell Biol 2009; 11:1017-23. [PMID: 19597485 DOI: 10.1038/ncb1915] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 04/28/2009] [Indexed: 12/20/2022]
Abstract
CDK4-pRB-E2F1 cell-cycle regulators are robustly expressed in non-proliferating beta cells, suggesting that besides the control of beta-cell number the CDK4-pRB-E2F1 pathway has a role in beta-cell function. We show here that E2F1 directly regulates expression of Kir6.2, which is a key component of the K(ATP) channel involved in the regulation of glucose-induced insulin secretion. We demonstrate, through chromatin immunoprecipitation analysis from tissues, that Kir6.2 expression is regulated at the promoter level by the CDK4-pRB-E2F1 pathway. Consistently, inhibition of CDK4, or genetic inactivation of E2F1, results in decreased expression of Kir6.2, impaired insulin secretion and glucose intolerance in mice. Furthermore we show that rescue of Kir6.2 expression restores insulin secretion in E2f1(-/-) beta cells. Finally, we demonstrate that CDK4 is activated by glucose through the insulin pathway, ultimately resulting in E2F1 activation and, consequently, increased expression of Kir6.2. In summary we provide evidence that the CDK4-pRB-E2F1 regulatory pathway is involved in glucose homeostasis, defining a new link between cell proliferation and metabolism.
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36
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Feng X, Chen Y, Zhao J, Tang C, Jiang Z, Geng B. Hydrogen sulfide from adipose tissue is a novel insulin resistance regulator. Biochem Biophys Res Commun 2009; 380:153-9. [DOI: 10.1016/j.bbrc.2009.01.059] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 01/10/2009] [Indexed: 10/21/2022]
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37
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Abstract
ATP-sensitive potassium (K(ATP)) channels play a key role in glucose-dependent insulin secretion in pancreatic beta-cells. Recently, activating mutations in beta-cell K(ATP) channels were found to be an important cause of neonatal diabetes. In some patients, these mutations may also affect K(ATP) channel function in muscles, nerves and brain which can result in a severe disease termed DEND syndrome (Developmental delay, Epilepsy and Neonatal Diabetes). This review focuses on mutations in the pore-forming K(ATP) channel subunit (Kir6.2) that cause neonatal diabetes and discusses recent advances in our understanding of clinical features of neonatal diabetes, its underlying molecular mechanisms and their impact on treatment.
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Affiliation(s)
- Kenju Shimomura
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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38
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Cifelli C, Boudreault L, Gong B, Bercier JP, Renaud JM. Contractile dysfunctions in ATP-dependent K+ channel-deficient mouse muscle during fatigue involve excessive depolarization and Ca2+ influx through L-type Ca2+ channels. Exp Physiol 2008; 93:1126-38. [PMID: 18586858 DOI: 10.1113/expphysiol.2008.042572] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Muscles deficient in ATP-dependent potassium (KATP) channels develop contractile dysfunctions during fatigue that may explain their apparently faster rate of fatigue compared with wild-type muscles. The objectives of this study were to determine: (1) whether the contractile dysfunctions, namely unstimulated force and depressed force recovery, result from excessive membrane depolarization and Ca2+ influx through L-type Ca2+ channels; and (2) whether reducing the magnitude of these two contractile dysfunctions reduces the rate of fatigue in KATP channel-deficient muscles. To reduce Ca2+ influx, we lowered the extracellular Ca2+ concentration ([Ca2+]o) from 2.4 to 0.6 mM or added 1 microM verapamil, an L-type Ca2+ channel blocker. Flexor digitorum brevis (FDB) muscles deficient in KATP channels were obtained by exposing wild-type muscles to 10 microM glibenclamide or by using FDB from Kir6.2-/- mice. Fatigue was elicited with one contraction per second for 3 min at 37 degrees C. In wild-type FDB, lowered [Ca2+]o or verapamil did not affect the decrease in peak tetanic force and unstimulated force during fatigue and force recovery following fatigue. In KATP channel-deficient FDB, lowered [Ca2+]o or verapamil slowed down the decrease in peak tetanic force recovery, reduced unstimulated force and improved force recovery. In Kir6.2-/- FDB, the rate of fatigue became slower than in wild-type FDB in the presence of verapamil. The cell membrane depolarized from -83 to -57 mV in normal wild-type FDB. The depolarizations in some glibenclamide-exposed fibres were similar to those of normal FDB, while in other fibres the cell membrane depolarized to -31 mV in 80 s, which was also the time when these fibres supercontracted. It is concluded that: (1) KATP channels are crucial in preventing excessive membrane depolarization and Ca2+ influx through L-type Ca2+ channels; and (2) they contribute to the decrease in force during fatigue.
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Affiliation(s)
- Carlo Cifelli
- University of Ottawa, Department of Cellular and Molecular Medicine, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
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Abstract
An explosion of work over the last decade has produced insight into the multiple hereditary causes of a nonimmunological form of diabetes diagnosed most frequently within the first 6 months of life. These studies are providing increased understanding of genes involved in the entire chain of steps that control glucose homeostasis. Neonatal diabetes is now understood to arise from mutations in genes that play critical roles in the development of the pancreas, of beta-cell apoptosis and insulin processing, as well as the regulation of insulin release. For the basic researcher, this work is providing novel tools to explore fundamental molecular and cellular processes. For the clinician, these studies underscore the need to identify the genetic cause underlying each case. It is increasingly clear that the prognosis, therapeutic approach, and genetic counseling a physician provides must be tailored to a specific gene in order to provide the best medical care.
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Affiliation(s)
- Lydia Aguilar-Bryan
- Pacific Northwest Diabetes Research Institute, 720 Broadway, Seattle, Washington 98122, USA.
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40
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Koster JC, Cadario F, Peruzzi C, Colombo C, Nichols CG, Barbetti F. The G53D mutation in Kir6.2 (KCNJ11) is associated with neonatal diabetes and motor dysfunction in adulthood that is improved with sulfonylurea therapy. J Clin Endocrinol Metab 2008; 93:1054-61. [PMID: 18073297 PMCID: PMC2266958 DOI: 10.1210/jc.2007-1826] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Mutations in the Kir6.2 subunit (KCNJ11) of the ATP-sensitive potassium channel (KATP) underlie neonatal diabetes mellitus. In severe cases, Kir6.2 mutations underlie developmental delay, epilepsy, and neonatal diabetes (DEND). All Kir6.2 mutations examined decrease the ATP inhibition of KATP, which is predicted to suppress electrical activity in neurons (peripheral and central), muscle, and pancreas. Inhibitory sulfonylureas (SUs) have been used successfully to treat diabetes in patients with activating Kir6.2 mutations. There are two reports of improved neurological features in SU-treated DEND patients but no report of such improvement in adulthood. OBJECTIVE The objective of the study was to determine the molecular basis of intermediate DEND in a 27-yr-old patient with a KCNJ11 mutation (G53D) and the patient's response to SU therapy. DESIGN The G53D patient was transferred from insulin to gliclazide and then to glibenclamide over a 160-d period. Motor function was assessed throughout. Electrophysiology assessed the effect of the G53D mutation on KATP activity. RESULTS The G53D patient demonstrated improved glycemic control and motor coordination with SU treatment, although glibenclamide was more effective than gliclazide. Reconstituted G53D channels exhibit reduced ATP sensitivity, which is predicted to suppress electrical activity in vivo. G53D channels coexpressed with SUR1 (the pancreatic and neuronal isoform) exhibit high-affinity block by gliclazide but are insensitive to block when coexpressed with SUR2A (the skeletal muscle isoform). High-affinity block by glibenclamide is present in G53D channels coexpressed with either SUR1 or SUR2A. CONCLUSION The results demonstrate that SUs can resolve motor dysfunction in an adult with intermediate DEND and that this improvement is due to inhibition of the neuronal but not skeletal muscle KATP.
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Affiliation(s)
- Joseph C Koster
- Washington University School of Medicine, Department of Cell Biology and Physiology, Box 8228, St. Louis, MO 63110, USA.
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41
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Xu J, Zhang L, Chou A, Allaby T, Bélanger G, Radziuk J, Jasmin BJ, Miki T, Seino S, Renaud JM. KATP channel-deficient pancreatic beta-cells are streptozotocin resistant because of lower GLUT2 activity. Am J Physiol Endocrinol Metab 2008; 294:E326-35. [PMID: 18042662 DOI: 10.1152/ajpendo.00296.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In wild-type mice, a single injection of streptozotocin (STZ, 200 mg/kg body wt) caused within 4 days severe hyperglycemia, hypoinsulinemia, significant glucose intolerance, loss of body weight, and the disappearance of pancreatic beta-cells. However, in ATP-sensitive K(+) channel (K(ATP) channel)-deficient mice (Kir6.2(-/-) mice), STZ had none of these effects. Exposing isolated pancreatic islets to STZ caused severe damage in wild-type but not in Kir6.2(-/-) islets. Following a single injection, plasma STZ levels were slightly less in Kir6.2(-/-) mice than in wild-type mice. Despite the difference in plasma STZ, wild-type and Kir6.2(-/-) liver accumulated the same amount of STZ, whereas Kir6.2(-/-) pancreas accumulated 4.1-fold less STZ than wild-type pancreas. Kir6.2(-/-) isolated pancreatic islets also transported less glucose than wild-type ones. Quantification of glucose transporter 2 (GLUT2) protein content by Western blot using an antibody with an epitope in the extracellular loop showed no significant difference in GLUT2 content between wild-type and Kir6.2(-/-) pancreatic islets. However, visualization by immunofluorescence with the same antibody gave rise to 32% less fluorescence in Kir6.2(-/-) pancreatic islets. The fluorescence intensity using another antibody, with an epitope in the COOH terminus, was 5.6 times less in Kir6.2(-/-) than in wild-type pancreatic islets. We conclude that 1) Kir6.2(-/-) mice are STZ resistant because of a decrease in STZ transport by GLUT2 in pancreatic beta-cells and 2) the decreased transport is due to a downregulation of GLUT2 activity involving an effect at the COOH terminus.
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MESH Headings
- Animals
- Antibiotics, Antineoplastic/blood
- Antibiotics, Antineoplastic/metabolism
- Antibiotics, Antineoplastic/pharmacology
- Blood Glucose/metabolism
- Blotting, Western
- Cytosol/metabolism
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Experimental/physiopathology
- Drug Resistance
- Glucose Transporter Type 2/genetics
- Glucose Transporter Type 2/metabolism
- In Vitro Techniques
- Insulin/blood
- Insulin-Secreting Cells/metabolism
- Islets of Langerhans/drug effects
- Islets of Langerhans/metabolism
- KATP Channels/deficiency
- KATP Channels/genetics
- KATP Channels/physiology
- Liver/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Fluorescence
- Pancreas/metabolism
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/physiology
- Streptozocin/blood
- Streptozocin/metabolism
- Streptozocin/pharmacology
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Affiliation(s)
- Jin Xu
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada
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42
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Abstract
Nutrient oxidation in beta cells generates a rise in [ATP]:[ADP] ratio. This reduces K(ATP) channel activity, leading to depolarization, activation of voltage-dependent Ca(2+) channels, Ca(2+) entry and insulin secretion. Consistent with this paradigm, loss-of-function mutations in the genes (KCNJ11 and ABCC8) that encode the two subunits (Kir6.2 and SUR1, respectively) of the ATP-sensitive K(+) (K(ATP)) channel underlie hyperinsulinism in humans, a genetic disorder characterized by dysregulated insulin secretion. In mice with genetic suppression of K(ATP) channel subunit expression, partial loss of K(ATP) channel conductance also causes hypersecretion, but unexpectedly, complete loss results in an undersecreting, mildly glucose-intolerant phenotype. When challenged by a high-fat diet, normal mice and mice with reduced K(ATP) channel density respond with hypersecretion, but mice with more significant or complete loss of K(ATP) channels cross over, or progress further, to an undersecreting, diabetic phenotype. It is our contention that in mice, and perhaps in humans, there is an inverse U-shaped response to hyperexcitabilty, leading first to hypersecretion but with further exacerbation to undersecretion and diabetes. The causes of the overcompensation and diabetic susceptibility are poorly understood but may have broader implications for the progression of hyperinsulinism and type 2 diabetes in humans.
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Affiliation(s)
- C G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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43
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Cifelli C, Bourassa F, Gariépy L, Banas K, Benkhalti M, Renaud JM. KATP channel deficiency in mouse flexor digitorum brevis causes fibre damage and impairs Ca2+ release and force development during fatigue in vitro. J Physiol 2007; 582:843-57. [PMID: 17510189 PMCID: PMC2075337 DOI: 10.1113/jphysiol.2007.130955] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Activation of the K(ATP) channels results in faster fatigue rates as the channels depress action potential amplitude, whereas abolishing the channel activity has no effect in whole extensor digitorum longus (EDL) and soleus muscles. In this study, we examined the effects of abolished K(ATP) channel activity during fatigue at 37 degrees C on free intracellular Ca(2+) (Ca(2+)(i)) and tetanic force using single muscle fibres and small muscle bundles from the flexor digitorum brevis (FDB). K(ATP) channel deficient muscle fibres were obtained (i) pharmacologically by exposing wild-type fibres to glibenclamide, and (ii) genetically using null mice for the Kir6.2 gene (Kir6.2(-/-) mice). Fatigue was elicited using 200 ms tetanic contractions every second for 3 min. This study demonstrated for the first time that abolishing K(ATP) channel activity at 37 degrees C resulted in faster fatigue rates, where decreases in peak Ca(2+)(i) and tetanic force were faster in K(ATP) channel deficient fibres than in control wild-type fibres. Furthermore, several contractile dysfunctions were also observed in K(ATP) channel deficient muscle fibre. They included partially or completely supercontracted single muscle fibres, greater increases in unstimulated Ca(2+)(i) and unstimulated force, and lower force recovery. We propose that the observed faster rate of fatigue in K(ATP) channel deficient fibres is because the decreases in peak Ca(2+)(i) and force caused by contractile dysfunctions prevail over the expected slower decreases when the channels do not depress action potential amplitude.
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Affiliation(s)
- Carlo Cifelli
- University of Ottawa, Department of Cellular and Molecular Medicine, 451 Smyth Rd, Ottawa, Ontario, Canada
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44
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Koo BK, Cho YM, Park BL, Cheong HS, Shin HD, Jang HC, Kim SY, Lee HK, Park KS. Polymorphisms of KCNJ11 (Kir6.2 gene) are associated with Type 2 diabetes and hypertension in the Korean population. Diabet Med 2007; 24:178-86. [PMID: 17257281 DOI: 10.1111/j.1464-5491.2006.02050.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS Kir6.2 is found in the pancreatic B-cell, cardiac and skeletal muscle and non-vascular smooth muscle. KCNJ11, encoding Kir6.2, has been shown to be associated with both Type 2 diabetes mellitus and cardiovascular disease in several populations. In this study, we investigated whether polymorphisms in KCNJ11 are associated with Type 2 diabetes and other metabolic phenotypes in the Korean population. METHODS We sequenced KCNJ11 to identify common polymorphisms using 24 Korean DNA samples. Of the 14 polymorphisms found in KCNJ11, six common ones [genomic sequence (g.)-1709A>T, g.-1525T>C, g.67G>A (E23K), g.570C>T (A190A), g.1009A>G (I337V), and g.1388C>T] were genotyped in 761 Type 2 diabetic patients and in 630 non-diabetic subjects. RESULTS All the polymorphic loci in KCNJ11 are in strong linkage disequilibrium in the Korean population and act as one haplotype block. g.67G>A and g.1009A>G were associated with an increased risk of Type 2 diabetes [age, sex, and body mass index (BMI)-adjusted odds ratios (OR) = 1.376 (1.085-1.745), P = 0.008 and 1.411 (1.111-1.791), P = 0.005, respectively], as was one haplotype (A-T-A-C-G-C in the order of polymorphisms as shown above) containing g.67A and g.1009G [OR = 1.359 (1.080-1.709), P = 0.009]. The haplotype (A-T-A-C-G-C) was also strongly associated with hypertension [OR = 1.655 (1.288-2.126), P < 0.001]. CONCLUSIONS Polymorphisms in KCNJ11 are associated with Type 2 diabetes and also with hypertension in the Korean population.
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Affiliation(s)
- B K Koo
- Department of Internal Medicine, Seoul National University College of Medicine, Chongno-Gu, Seoul, Korea
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45
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Malecki MT, Skupien J, Klupa T, Wanic K, Mlynarski W, Gach A, Solecka I, Sieradzki J. Transfer to sulphonylurea therapy in adult subjects with permanent neonatal diabetes due to KCNJ11-activating [corrected] mutations: evidence for improvement in insulin sensitivity. Diabetes Care 2007; 30:147-9. [PMID: 17192350 DOI: 10.2337/dc06-1628] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Maciej T Malecki
- Department of Metabolic Diseases, Jagiellonian University, Medical College, 15 Kopernika St., 31-501 Krakow, Poland.
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46
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SUKHODUB ANDREY, JOVANOVIĆ SOFIJA, DU QINGYOU, BUDAS GRANT, CLELLAND ALLYSONK, SHEN MEI, SAKAMOTO KEI, TIAN RONG, JOVANOVIĆ ALEKSANDAR. AMP-activated protein kinase mediates preconditioning in cardiomyocytes by regulating activity and trafficking of sarcolemmal ATP-sensitive K(+) channels. J Cell Physiol 2007; 210:224-36. [PMID: 17044064 PMCID: PMC2128052 DOI: 10.1002/jcp.20862] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Brief periods of ischemia and reperfusion that precede sustained ischemia lead to a reduction in myocardial infarct size. This phenomenon, known as ischemic preconditioning, is mediated by signaling pathway(s) that is complex and yet to be fully defined. AMP-activated kinase (AMPK) is activated in cells under conditions associated with ATP depletion and increased AMP/ATP ratio. In the present study, we have taken advantage of a cardiac phenotype overexpressing a dominant negative form of the alpha2 subunit of AMPK to analyze the role, if any, that AMPK plays in preconditioning the heart. We have found that myocardial preconditioning activates AMPK in wild type, but not transgenic mice. Cardiac cells from transgenic mice could not be preconditioned, as opposed to cells from the wild type. The cytoprotective effect of AMPK was not related to the effect that preconditioning has on mitochondrial membrane potential as revealed by JC-1, a mitochondrial membrane potential-sensitive dye, and laser confocal microscopy. In contrast, experiments with di-8-ANEPPS, a sarcolemmal-potential sensitive dye, has demonstrated that intact AMPK activity is required for preconditioning-induced shortening of the action membrane potential. The preconditioning-induced activation of sarcolemmal K(ATP) channels was observed in wild type, but not in transgenic mice. HMR 1098, a selective inhibitor of sarcolemmal K(ATP) channels opening, inhibited preconditioning-induced shortening of action membrane potential as well as cardioprotection afforded by AMPK. Immunoprecipitation followed by Western blotting has shown that AMPK is essential for preconditioning-induced recruitment of sarcolemmal K(ATP) channels. Based on the obtained results, we conclude that AMPK mediates preconditioning in cardiac cells by regulating the activity and recruitment of sarcolemmal K(ATP) channels without being a part of signaling pathway that regulates mitochondrial membrane potential.
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Affiliation(s)
- ANDREY SUKHODUB
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - SOFIJA JOVANOVIĆ
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - QINGYOU DU
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - GRANT BUDAS
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - ALLYSON K. CLELLAND
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - MEI SHEN
- Department of Medicine, Cardiovascular Division, Nuclear Magnetic Resonance Laboratory for Physiological Chemistry, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - KEI SAKAMOTO
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee, UK
| | - RONG TIAN
- Department of Medicine, Cardiovascular Division, Nuclear Magnetic Resonance Laboratory for Physiological Chemistry, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - ALEKSANDAR JOVANOVIĆ
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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47
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Kato Y, Ozaki N, Yamada T, Miura Y, Oiso Y. H-89 potentiates adipogenesis in 3T3-L1 cells by activating insulin signaling independently of protein kinase A. Life Sci 2006; 80:476-83. [PMID: 17056071 DOI: 10.1016/j.lfs.2006.09.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 09/17/2006] [Accepted: 09/28/2006] [Indexed: 10/24/2022]
Abstract
Among four kinds of protein kinase A (PKA) inhibitors tested, H-89 exhibited a unique action to remarkably enhance adipocyte differentiation of 3T3-L1 cells, whereas the other three PKA inhibitors, PKA inhibitor Fragment 14-22 (PKI), Rp-cAMP, and KT 5720, did not enhance adipocyte differentiation. H-85, which is an inactive form of H-89, exhibited a similar enhancing effect on adipocyte differentiation. H-89 also potentiated the phosphorylation of Akt and extracellular signal-regulated kinase (ERK) 1/2 in 3T3-L1 cells, which function as downstream signaling of insulin. Phosphoinositide 3-kinase (PI3K) inhibitor wortmannin and mitogen-activated protein kinase kinase (MEK) inhibitor PD 98059 suppressed both the H-89-induced promotion of adipocyte differentiation and the H-89-induced potentiation of phosphorylation of Akt and ERK1/2. Rho kinase inhibitor Y-27632 also promoted the phosphorylation of both Akt and ERK1/2 and enhanced adipocyte differentiation, although its effect was somewhat less than that of H-89. Even when cells were treated with a mixture of Y-27632 and H-89, the additive enhancing effects on both the insulin signaling and adipocyte differentiation were not detected. Therefore, it is suggested that the major possible mechanism whereby H-89 potentiates adipocyte differentiation of 3T3-L1 cells is activation of insulin signaling that is elicited mostly by inhibiting Rho/Rho kinase pathway.
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Affiliation(s)
- Yoshiro Kato
- Department of Endocrinology and Diabetes, Field of Internal Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
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48
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Remedi MS, Rocheleau JV, Tong A, Patton BL, McDaniel ML, Piston DW, Koster JC, Nichols CG. Hyperinsulinism in mice with heterozygous loss of K(ATP) channels. Diabetologia 2006; 49:2368-78. [PMID: 16924481 DOI: 10.1007/s00125-006-0367-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 05/30/2006] [Indexed: 10/24/2022]
Abstract
AIMS/HYPOTHESIS ATP-sensitive K(+) (K(ATP)) channels couple glucose metabolism to insulin secretion in pancreatic beta cells. In humans, loss-of-function mutations of beta cell K(ATP) subunits (SUR1, encoded by the gene ABCC8, or Kir6.2, encoded by the gene KCNJ11) cause congenital hyperinsulinaemia. Mice with dominant-negative reduction of beta cell K(ATP) (Kir6.2[AAA]) exhibit hyperinsulinism, whereas mice with zero K(ATP) (Kir6.2(-/-)) show transient hyperinsulinaemia as neonates, but are glucose-intolerant as adults. Thus, we propose that partial loss of beta cell K(ATP) in vivo causes insulin hypersecretion, but complete absence may cause insulin secretory failure. MATERIALS AND METHODS Heterozygous Kir6.2(+/-) and SUR1(+/-) animals were generated by backcrossing from knockout animals. Glucose tolerance in intact animals was determined following i.p. loading. Glucose-stimulated insulin secretion (GSIS), islet K(ATP) conductance and glucose dependence of intracellular Ca(2+) were assessed in isolated islets. RESULTS In both of the mechanistically distinct models of reduced K(ATP) (Kir6.2(+/-) and SUR1(+/-)), K(ATP) density is reduced by approximately 60%. While both Kir6.2(-/-) and SUR1(-/-) mice are glucose-intolerant and have reduced glucose-stimulated insulin secretion, heterozygous Kir6.2(+/-) and SUR1(+/-) mice show enhanced glucose tolerance and increased GSIS, paralleled by a left-shift in glucose dependence of intracellular Ca(2+) oscillations. CONCLUSIONS/INTERPRETATION The results confirm that incomplete loss of beta cell K(ATP) in vivo underlies a hyperinsulinaemic phenotype, whereas complete loss of K(ATP) underlies eventual secretory failure.
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Affiliation(s)
- M S Remedi
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110, USA.
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49
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Choeiri C, Staines WA, Miki T, Seino S, Renaud JM, Teutenberg K, Messier C. Cerebral glucose transporters expression and spatial learning in the K-ATP Kir6.2(-/-) knockout mice. Behav Brain Res 2006; 172:233-9. [PMID: 16797737 DOI: 10.1016/j.bbr.2006.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 04/28/2006] [Accepted: 05/04/2006] [Indexed: 11/15/2022]
Abstract
K-ATP channels formed of the Sur and Kir subunits are widely distributed in the brain. Sur1-Kir6.2 is the most common combination of K-ATP channel subunits in the brain and Kir6.2 plays an important role in glucose metabolism through pancreatic insulin secretion or hypothalamic glucose sensing. K-ATP channels have also been reported to play a role in memory processing. Therefore, the aim of the present experiment is to assess the gene and protein expression of GLUT1, GLUT3 and GLUT4 in various brain regions of Kir6.2(-/-) K-ATP knockout mice and to test their working memory performance. GLUT4 was measured using two antibodies, one recognizing an intracellular epitope and the other, an extracellular epitope. Relative to their corresponding wild type, semi-quantitative immunohistochemistry showed that GLUT4 protein expression as measured by a GLUT4 antibody recognizing an extracellular epitope was increased in the Kir6.2(-/-) K-ATP mice. However, there was only a small increase in GLUT4 labeling using the GLUT4 antibody recognizing the intracellular epitope. These results suggest a compensatory higher GLUT4 inclusion at the cellular neuronal membrane in the cerebral cortex, hippocampus and cerebellum of the Kir6.2(-/-) K-ATP knockout mice. However, there was no change in GLUT4 gene expression assessed by TaqMan PCR except for a decrease in the cerebellum of these mice. Working memory performance of the Kir6.2(-/-) K-ATP mice was disrupted at age of 12 weeks but not at 5 weeks. The mild glucose intolerance that is observed in the Kir6.2 knockout mice is unlikely to have created the memory deficits observed. Rather, in light of the effects of K-ATP channel modulators on memory, the memory deficits in the Kir6.2(-/-) K-ATP mice are more likely due to the absence of the Kir6.2 and possible disruption of the GLUT4 activity in the brain.
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Affiliation(s)
- C Choeiri
- Psychology Faculty, Fresno Pacific University, 1717 South Chestnut Ave. Fresno, CA 93702, USA
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50
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Skupien J, Malecki MT, Mlynarski W, Klupa T, Wanic K, Gach A, Solecka I, Sieradzki J. Assessment of insulin sensitivity in adults with permanent neonatal diabetes mellitus due to mutations in the KCNJ11 gene encoding Kir6.2. Rev Diabet Stud 2006; 3:17-20. [PMID: 17491708 PMCID: PMC1783575 DOI: 10.1900/rds.2006.3.17] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Activating mutations in the KCNJ11 gene encoding the Kir6.2 subunit of ATP-sensitive potassium channel have been described in patients with permanent neonatal diabetes mellitus (PNDM). The main pathophysiological feature of PNDM associated with Kir6.2 mutations is a profound defect in insulin secretion. However, the expression of Kir6.2 protein is not limited to beta-cells; it also includes skeletal muscles, heart, brain, and peripheral nerves. Thus, the hypothesis that Kir6.2 mutations may influence insulin sensitivity in humans seems justified. Moreover, this notion is additionally supported by an animal model of Kir6.2 knock-out mice. Four adult carriers of a Kir6.2 mutation from the Polish population (mean age 31.5 years, range 20-50) were available for this study that aimed to evaluate their insulin sensitivity by the hyperinsulinemic euglycemic clamp technique. Three subjects carried the R201H mutation and one patient was a carrier of the K170N mutation. In addition, eight healthy volunteers with normal glucose tolerance were examined for comparison (mean age 31.0 years, range 20-41). The mean M value, i.e. the amount of metabolized glucose, for PNDM cases equaled 4.49 mg/(kg x min) (range 2.76-6.66) and was significantly lower than in the control group (9.64 mg/(kg x min), range 4.59-18.00). This observation suggests that impaired insulin sensitivity, in addition to profoundly decreased insulin secretion, contributes to the clinical picture of PNDM resulting from mutations in the Kir6.2 gene. An additional factor that might influence insulin sensitivity in our diabetes patients is glucose toxicity that may have appeared due to poor metabolic control prior to the examination (mean HbA1c = 8.95%). The intriguing question to be answered in the future is whether an improvement in insulin action could be seen following the transfer of Kir6.2 mutation carriers to sulphonylurea compounds.
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Affiliation(s)
- Jan Skupien
- Department of Metabolic Diseases, Jagiellonian University, Medical College, Krakow, Poland
| | - Maciej T. Malecki
- Department of Metabolic Diseases, Jagiellonian University, Medical College, Krakow, Poland
- Address correspondence to: Maciej T. Malecki, e-mail:
| | - Wojciech Mlynarski
- Clinic of Pediatrics, Institute of Pediatrics, Medical University of Lodz, Poland
| | - Tomasz Klupa
- Department of Metabolic Diseases, Jagiellonian University, Medical College, Krakow, Poland
| | - Krzysztof Wanic
- Department of Metabolic Diseases, Jagiellonian University, Medical College, Krakow, Poland
| | - Agnieszka Gach
- Clinic of Pediatrics, Institute of Pediatrics, Medical University of Lodz, Poland
| | - Iwona Solecka
- Department of Metabolic Diseases, Jagiellonian University, Medical College, Krakow, Poland
| | - Jacek Sieradzki
- Department of Metabolic Diseases, Jagiellonian University, Medical College, Krakow, Poland
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