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Kong DW, Du LD, Liu RZ, Yuan TY, Wang SB, Wang YH, Lu Y, Fang LH, Du GH. Baicalein attenuates rotenone-induced SH-SY5Y cell apoptosis through binding to SUR1 and activating ATP-sensitive potassium channels. Acta Pharmacol Sin 2024; 45:480-489. [PMID: 37993535 PMCID: PMC10834402 DOI: 10.1038/s41401-023-01187-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/23/2023] [Indexed: 11/24/2023] Open
Abstract
Dopaminergic neurons in the substantia nigra (SN) expressing SUR1/Kir6.2 type ATP-sensitive potassium channels (K-ATP) are more vulnerable to rotenone or metabolic stress, which may be an important reason for the selective degeneration of neurons in Parkinson's disease (PD). Baicalein has shown neuroprotective effects in PD animal models. In this study, we investigated the effect of baicalein on K-ATP channels and the underlying mechanisms in rotenone-induced apoptosis of SH-SY5Y cells. K-ATP currents were recorded from SH-SY5Y cells using whole-cell voltage-clamp recording. Drugs dissolved in the external solution at the final concentration were directly pipetted onto the cells. We showed that rotenone and baicalein opened K-ATP channels and increased the current amplitudes with EC50 values of 0.438 μM and 6.159 μM, respectively. K-ATP channel blockers glibenclamide (50 μM) or 5-hydroxydecanoate (5-HD, 250 μM) attenuated the protective effects of baicalein in reducing reactive oxygen species (ROS) content and increasing mitochondrial membrane potential and ATP levels in rotenone-injured SH-SY5Y cells, suggesting that baicalein protected against the apoptosis of SH-SY5Y cells by regulating the effect of rotenone on opening K-ATP channels. Administration of baicalein (150, 300 mg·kg-1·d-1, i.g.) significantly inhibited rotenone-induced overexpression of SUR1 in SN and striatum of rats. We conducted surface plasmon resonance assay and molecular docking, and found that baicalein had a higher affinity with SUR1 protein (KD = 10.39 μM) than glibenclamide (KD = 24.32 μM), thus reducing the sensitivity of K-ATP channels to rotenone. Knockdown of SUR1 subunit reduced rotenone-induced apoptosis and damage of SH-SY5Y cells, confirming that SUR1 was an important target for slowing dopaminergic neuronal degeneration in PD. Taken together, we demonstrate for the first time that baicalein attenuates rotenone-induced SH-SY5Y cell apoptosis through binding to SUR1 and activating K-ATP channels.
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Affiliation(s)
- De-Wen Kong
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Li-da Du
- Shandong Soteria Pharmaceutical Co Ltd., Jinan, 250022, China
| | - Run-Zhe Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Tian-Yi Yuan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Shou-Bao Wang
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Yue-Hua Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Yang Lu
- Beijing Key Laboratory of Polymorphic Drugs, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Lian-Hua Fang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
| | - Guan-Hua Du
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
- Beijing Key Laboratory of Drug Targets Identification and Drug Screening, National Center for Pharmaceutical Screening, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
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Vazquez Arreola E, Knowler WC, Baier LJ, Hanson RL. Effects of the ABCC8 R1420H loss-of-function variant on beta-cell function, diabetes incidence, and retinopathy. BMJ Open Diabetes Res Care 2023; 11:e003700. [PMID: 38164708 PMCID: PMC10729258 DOI: 10.1136/bmjdrc-2023-003700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/11/2023] [Indexed: 01/03/2024] Open
Abstract
INTRODUCTION The ABCC8 gene regulates insulin secretion and plays a critical role in glucose homeostasis. The effects of an ABCC8 R1420H loss-of-function variant on beta-cell function, incidence of type 2 diabetes, and age-at-onset, prevalence, and progression of diabetes complications were assessed in a longitudinal study in American Indians. RESEARCH DESIGN AND METHODS We analyzed beta-cell function through the relationship between insulin secretion and insulin sensitivity in members of this population without diabetes aged ≥5 years using standard major axis regression. We used hierarchical logistic regression models to study cross-sectional associations with diabetes complications including increased albuminuria (albumin-to-creatinine ratio (ACR) ≥30 mg/g), severe albuminuria (ACR ≥300 mg/g), reduced estimated glomerular filtration rate (eGFR <60 mL/min/1.73 m2), and retinopathy. This study included 7675 individuals (254 variant carriers) previously genotyped for the R1420H with available phenotypic data and with a median follow-up time of 13.5 years (IQR 4.5-26.8). RESULTS Variant carriers had worse beta-cell function than non-carriers (p=0.0004; on average estimated secretion was 22% lower, in carriers), in children and adults, with no difference in insulin sensitivity (p=0.50). At any body mass index and age before 35 years, carriers had higher type 2 diabetes incidence. This variant did not associate with prevalence of increased albuminuria (OR 0.87, 95% CI 0.66 to 1.16), severe albuminuria (OR 0.96, 95% CI 0.55 to 1.68), or reduced eGFR (OR 0.44, 95% CI 0.18 to 1.06). By contrast, the variant significantly associated with higher retinopathy prevalence (OR 1.74, 95% CI 1.19 to 2.53) and this association was only partially mediated (<11%) by glycemia, duration of diabetes, risk factors of retinopathy, or insulin use. Retinopathy prevalence in carriers was higher regardless of diabetes presence. CONCLUSIONS The ABCC8 R1420H variant is associated with increased risks of diabetes and of retinopathy, which may be partially explained by higher glycemia levels and worse beta-cell function.
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Affiliation(s)
- Elsa Vazquez Arreola
- National Institute of Diabetes and Digestive and Kidney Diseases Phoenix Epidemiology and Clinical Research Branch, Phoenix, Arizona, USA
| | - William C Knowler
- National Institute of Diabetes and Digestive and Kidney Diseases Phoenix Epidemiology and Clinical Research Branch, Phoenix, Arizona, USA
| | - Leslie J Baier
- National Institute of Diabetes and Digestive and Kidney Diseases Phoenix Epidemiology and Clinical Research Branch, Phoenix, Arizona, USA
| | - Robert L Hanson
- National Institute of Diabetes and Digestive and Kidney Diseases Phoenix Epidemiology and Clinical Research Branch, Phoenix, Arizona, USA
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Gęgotek A, Skrzydlewska E. The Role of ABC Transporters in Skin Cells Exposed to UV Radiation. Int J Mol Sci 2022; 24:ijms24010115. [PMID: 36613554 PMCID: PMC9820374 DOI: 10.3390/ijms24010115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/17/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
ABC transporters are expressed in skin cells to protect them against harmful xenobiotics. Moreover, these transmembrane proteins have a number of additional functions that ensure skin homeostasis. This review summarizes the current knowledge about the role of specific ABC proteins in the skin, including multi-drug resistance transporters (MDR1/3), the transporter associated with antigen processing 1/2 (TAP1/2), the cystic fibrosis transmembrane conductance regulator (CFTR), sulfonylurea receptors (SUR1/2), and the breast cancer resistance protein (BCRP). Additionally, the effect of UV radiation on ABC transporters is shown. The exposure of skin cells to UV radiation often leads to increased activity of ABC transporters-as has been observed in the case of MDRs, TAPs, CFTR, and BCRP. A different effect of oxidative stress has been observed in the case of mitochondrial SURs. However, the limited data in the literature-as indicated in this article-highlights the limited number of experimental studies dealing with the role of ABC transporters in the physiology and pathophysiology of skin cells and the skin as a whole. At the same time, the importance of such knowledge in relation to the possibility of daily exposure to UV radiation and xenobiotics, used for both skin care and the treatment of its diseases, is emphasized.
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He Y, Chang Y, Peng Y, Zhu J, Liu K, Chen J, Wu Y, Ji Z, Lin Z, Wang S, Gupta S, Zang N, Pan S, Huang K. Glibenclamide Directly Prevents Neuroinflammation by Targeting SUR1-TRPM4-Mediated NLRP3 Inflammasome Activation In Microglia. Mol Neurobiol 2022; 59:6590-6607. [PMID: 35972671 DOI: 10.1007/s12035-022-02998-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 08/07/2022] [Indexed: 10/15/2022]
Abstract
Glibenclamide (GLB) reduces brain edema and improves neurological outcome in animal experiments and preliminary clinical studies. Recent studies also suggested a strong anti-inflammatory effect of GLB, via inhibiting nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome activation. However, it remains unknown whether the anti-inflammatory effect of GLB is independent of its role in preventing brain edema, and how GLB inhibits the NLRP3 inflammasome is not fully understood. Sprague-Dawley male rats underwent 10-min asphyxial cardiac arrest and cardiopulmonary resuscitation or sham-operation. The Trpm4 siRNA and GLB were injected to block sulfonylurea receptor 1-transient receptor potential M4 (SUR1-TRPM4) channel in rats. Western blotting, quantitative real-time polymerase chain reaction, behavioral analysis, and histological examination were used to evaluate the role of GLB in preventing NLRP3-mediated neuroinflammation through inhibiting SUR1-TRPM4, and corresponding neuroprotective effect. To further explore the underlying mechanism, BV2 cells were subjected to lipopolysaccharides, or oxygen-glucose deprivation/reperfusion. Here, in rat model of cardiac arrest with brain edema combined with neuroinflammation, GLB significantly alleviated neurocognitive deficit and neuropathological damage, via the inhibition of microglial NLRP3 inflammasome activation by blocking SUR1-TRPM4. Of note, the above effects of GLB could be achieved by knockdown of Trpm4. In vitro under circumstance of eliminating distractions from brain edema, SUR1-TRPM4 and NLRP3 inflammasome were also activated in BV2 cells subjected to lipopolysaccharides, or oxygen-glucose deprivation/reperfusion, which could be blocked by GLB or 9-phenanthrol, a TRPM4 inhibitor. Importantly, activation of SUR1-TRPM4 in BV2 cells required the P2X7 receptor-mediated Ca2+ influx, which in turn magnified the K+ efflux via the Na+ influx-driven opening of K+ channels, leading to the NLRP3 inflammasome activation. These findings suggest that GLB has a direct anti-inflammatory neuroprotective effect independent of its role in preventing brain edema, through inhibition of SUR1-TRPM4 which amplifies K+ efflux and promotes NLRP3 inflammasome activation.
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Affiliation(s)
- Yihua He
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Yuan Chang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Yuqin Peng
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Juan Zhu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Kewei Liu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Jiancong Chen
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Yongming Wu
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Zhong Ji
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Zhenzhou Lin
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Shengnan Wang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Sohan Gupta
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Nailiang Zang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China
| | - Suyue Pan
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China.
| | - Kaibin Huang
- Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou North Avenue 1838#, 510515, Guangzhou, China.
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Roessler HI, van der Heuvel LM, Shields K, Guilliams KP, Knoers NVAM, van Haaften G, Grange DK, van Haelst MM. Behavioral and cognitive functioning in individuals with Cantú syndrome. Am J Med Genet A 2021; 185:2434-2444. [PMID: 34056838 DOI: 10.1002/ajmg.a.62348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/20/2021] [Accepted: 05/07/2021] [Indexed: 11/07/2022]
Abstract
Cantú syndrome (CS) is caused by pathogenic variants in ABCC9 and KCNJ8 encoding the regulatory and pore-forming subunits of ATP-sensitive potassium (KATP ) channels. CS is characterized by congenital hypertrichosis, distinctive facial features, peripheral edema, and cardiac and neurodevelopmental abnormalities. Behavioral and cognitive issues have been self-reported by some CS individuals, but results of formal standardized investigations have not been published. To assess the cognitive profile, social functioning, and psychiatric symptoms in a large group of CS subjects systematically in a cross-sectional manner, we invited 35 individuals (1-69 years) with confirmed ABCC9 variants and their relatives to complete various commonly applied standardized age-related questionnaires, including the Kaufman brief intelligence test 2, the social responsiveness scale-2, and the Achenbach system of empirically based assessment. The majority of CS individuals demonstrated average verbal and nonverbal intelligence compared to the general population. Fifteen percent of cases showed social functioning strongly associated with a clinical diagnosis of autism spectrum disorder. Both externalizing and internalizing problems were also present in this cohort. In particular, anxiety, anxiety or attention deficit hyperactivity disorder, and autism spectrum behaviors were predominantly observed in the younger subjects in the cohort (≥25%), but this percentage decreased markedly in adults.
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Affiliation(s)
- Helen I Roessler
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Lieke M van der Heuvel
- Department of Clinical Genetics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Kathleen Shields
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kristin P Guilliams
- Division of Pediatric Neurology, Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Pediatric Critical Care, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nine V A M Knoers
- Department of Genetics, University Medical Center Groningen, Groningen, The Netherlands
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Dorothy K Grange
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for the Investigation of Membrane Excitability Diseases (CIMED), St. Louis, Missouri, USA
| | - Mieke M van Haelst
- Department of Clinical Genetics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Clinical Genetics, VU Medical Center, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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Douris V, Steinbach D, Panteleri R, Livadaras I, Pickett JA, Van Leeuwen T, Nauen R, Vontas J. Resistance mutation conserved between insects and mites unravels the benzoylurea insecticide mode of action on chitin biosynthesis. Proc Natl Acad Sci U S A 2016; 113:14692-14697. [PMID: 27930336 PMCID: PMC5187681 DOI: 10.1073/pnas.1618258113] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistant Plutella xylostella at the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) in Drosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding fly CHS1 gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin-an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro.
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Affiliation(s)
- Vassilis Douris
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, GR-70013 Heraklion, Crete, Greece
- Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-70013 Heraklion, Crete, Greece
| | - Denise Steinbach
- Bayer CropScience AG, R&D Pest Control Biology, D-40789 Mannheim, Germany
- Developmental Biology, Department of Biology, Martin-Luther University Halle-Wittenberg, 06120 Halle, Germany
| | - Rafaela Panteleri
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, GR-70013 Heraklion, Crete, Greece
- Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-70013 Heraklion, Crete, Greece
| | - Ioannis Livadaras
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, GR-70013 Heraklion, Crete, Greece
| | - John Anthony Pickett
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Hertfordshire, Harpenden AL5 2JQ, United Kingdom;
| | - Thomas Van Leeuwen
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - Ralf Nauen
- Bayer CropScience AG, R&D Pest Control Biology, D-40789 Mannheim, Germany;
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, GR-70013 Heraklion, Crete, Greece;
- Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, GR-11855 Athens, Greece
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Liu SY, Tian HM, Liao DQ, Chen YF, Gou ZP, Xie XY, Li XJ. The effect of gliquidone on KATP channels in pancreatic β-cells, cardiomyocytes, and vascular smooth muscle cells. Diabetes Res Clin Pract 2015; 109:334-9. [PMID: 26044612 DOI: 10.1016/j.diabres.2015.05.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/30/2015] [Accepted: 05/02/2015] [Indexed: 02/05/2023]
Abstract
AIMS Sulfonylurea drugs exert an insulinotropic effect through ATP-sensitive potassium (KATP) channel inhibition in pancreatic islet cells. These channels are also expressed in cardiomyocytes and vascular smooth muscle cells (VSMCs), suggesting potential for adverse cardiovascular effects. We evaluated the effects of Gliquidone (Glq) on sulfonylurea receptors in HIT-T15 cells (SUR1), cardiomyocytes (SUR2A), and VSMCs (SUR2B). METHODS The concentration-dependent effects of Glq (0.001-500 μM) on KATP channels were assessed using whole-cell patch clamp in HIT-T15 cells, rat cardiomyocytes, and VSMCs. Parallel studies using Glibenclamide (Glb) (0.001-10 μM) and Gliclazide (Glc) (0.01-500 μM)were conducted as controls. RESULTS In HIT-T15 cells, Glb exhibited the lowest IC50 (0.03 μM), as compared to Glq (0.45μM) and Glc (1.21μM). However, Glq had higher IC50 in cardiomyoctes and VSMCs, as compared to Glb (119.1 vs. 0.01 and 149.7 vs. 0.09 μM, respectively), suggesting that Glq is more selective to β-cells than Glb. Thus, Glq may have fewer side effects in cardiomyoctes and VSMCs. CONCLUSIONS Glq is a highly selective SUR secretagogue with moderate affinity to β-cells, but low affinity to cardiomyocytes and VSMCs. Our data also reveal the non-selective nature of Glb, as evidenced by high binding affinity to KATP channels in all the three cell types examined.
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Affiliation(s)
- Shu-Yi Liu
- Division of Endocrinology and Metabolism Internal Medicine, West China Hospital, Sichuan University, Chengdu, China; Division of Endocrinology & Metabolism, The First People's Hospital of Chengdu, Chengdu, China
| | - Hao-Min Tian
- Division of Endocrinology and Metabolism Internal Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Da-Qing Liao
- Laboratory of Anesthesia and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Yan-Fang Chen
- Laboratory of Anesthesia and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Zhong-Ping Gou
- Division of Endocrinology and Metabolism Internal Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Xiao-Ying Xie
- Division of Endocrinology and Metabolism Internal Medicine, West China Hospital, Sichuan University, Chengdu, China
| | - Xiu-Jun Li
- Division of Endocrinology and Metabolism Internal Medicine, West China Hospital, Sichuan University, Chengdu, China.
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Usuda R. [Sulfonylurea]. Nihon Rinsho 2015; 73:409-415. [PMID: 25812366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
SU drug promotes insulin secretion by acting on pancreatic β cell. The hypoglycemic effect is the most powerful among oral diabetic drugs with high cost-effectiveness. Particularly for the Japanese with type 2 diabetes caused by a decrease in insulin secretion as a main pathological condition, it was widely used until the present since 1957 and largely contributed for the sickness. On the other hand, it is true that a number of issues such as a prolonged hypoglycemic coma or obesity due to a neglect of proper usage, patient education, and a possibility of second failure have been discussed so far. After a structure of K(ATP) channel on pancreatic β cell as playing an important role with insulin secretion is clarified recently and neonatal diabetes mellitus by the genetic defect is reported, a new possibility for SU drug receives attention. Furthermore, a receptor of SU drug on β cell membrane was solely known as a target molecule for SU drug, but since a binding to Epac2 as a protein to detect a part of SU drug's cAMP signal within β cell is determined, a relation with an enhancing mechanism of insulin secretion by incretin is being clarified at present. As understanding a new potential for SU drug, we consider a positioning and proper usage for SU drug again.
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Banerjee I, Avatapalle B, Padidela R, Stevens A, Cosgrove KE, Clayton PE, Dunne MJ. Integrating genetic and imaging investigations into the clinical management of congenital hyperinsulinism. Clin Endocrinol (Oxf) 2013; 78:803-13. [PMID: 23347463 DOI: 10.1111/cen.12153] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/03/2013] [Accepted: 01/14/2013] [Indexed: 11/27/2022]
Abstract
Congenital Hyperinsulinism (CHI) is a rare but important cause of hypoglycaemia in infancy. CHI is a heterogeneous disease, but has a strong genetic basis; a number of genetic causes have been identified with CHI in about a third of individuals, chiefly in the genes that code for the ATP sensitive K(+) channels (KATP ) in the pancreatic β-cells. Rapid KATP channel gene testing is a critical early step in the diagnostic algorithm of CHI, with paternal heterozygosity correlating with the occurrence of focal lesions. Imaging investigations to diagnose and localize solitary pancreatic foci have evolved over the last decade with (18)F-DOPA PET-CT scanning as the current diagnostic tool of choice. Although clinical management of CHI has improved significantly with the application of genetic screening and imaging investigations, much remains to be uncovered. This includes a better understanding of the molecular mechanisms for dysregulated insulin release in those patients without known genetic mutations, and the development of biomarkers that could characterize CHI, including long-term prognosis and targeted treatment planning, i.e. 'personalised medicine'. From the perspective of pancreatic imaging, it would be important to achieve greater specificity of diagnosis not only for focal lesions but also for diffuse and atypical forms of the disease.
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Affiliation(s)
- I Banerjee
- Paediatric Endocrinology, Royal Manchester Children's Hospital, Manchester, UK.
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Yorifuji T, Kawakita R, Hosokawa Y, Fujimaru R, Matsubara K, Aizu K, Suzuki S, Nagasaka H, Nishibori H, Masue M. Efficacy and safety of long-term, continuous subcutaneous octreotide infusion for patients with different subtypes of KATP-channel hyperinsulinism. Clin Endocrinol (Oxf) 2013; 78:891-7. [PMID: 23067144 DOI: 10.1111/cen.12075] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 07/31/2012] [Accepted: 10/10/2012] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To evaluate the efficacy of long-term, continuous, subcutaneous octreotide infusion for congenital hyperinsulinism caused by mutations in the KATP-channel genes, KCNJ11 and ABCC8. PATIENTS Fifteen Japanese patients with diazoxide-unresponsive, KATP-channel hyperinsulinism. METHODS Molecular diagnoses were made by sequencing and multiple ligation-dependent probe amplification analysis. In patients with paternally inherited, monoallelic mutations, 18F-DOPA PET scans were performed to determine the location of the lesion. The patients were treated with continuous, subcutaneous octreotide infusion at a dosage of up to 25 μg/kg/day, using an insulin pump to maintain blood glucose levels higher than 3.33 mmol/l. Additional treatments (IV glucose, glucagon or enteral feeding) were administered as needed. The efficacy of the treatment was assessed in patients who received octreotide for 4 months to 5.9 years. RESULTS Three patients had biallelic mutations, and 12 had monoallelic, paternally inherited mutations. Four patients with monoallelic mutations showed diffuse 18F-DOPA uptake, whereas seven patients showed focal uptake. Octreotide was effective in all the patients. The patients with biallelic mutations required a higher dosage (17-25 μg/kg/day), and two patients required additional treatments. By contrast, the patients with monoallelic mutations required a lower dosage (0.5-21 μg/kg/day) irrespective of the PET results and mostly without additional treatments. Treatment was discontinued in three patients at 2.5, 3.3 and 5.9 years of age, without psychomotor delay. Except for growth deceleration at a higher dosage, no significant adverse effects were noted. CONCLUSIONS Long-term, continuous, subcutaneous octreotide infusion is a feasible alternative to surgery especially for patients with monoallelic KATP-channel mutations.
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Affiliation(s)
- Tohru Yorifuji
- Department of Pediatric Endocrinology and Metabolism, Children's Medical Center, Osaka City General Hospital, Osaka, Japan.
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Cheng-Xue R, Gómez-Ruiz A, Antoine N, Noël LA, Chae HY, Ravier MA, Chimienti F, Schuit FC, Gilon P. Tolbutamide controls glucagon release from mouse islets differently than glucose: involvement of K(ATP) channels from both α-cells and δ-cells. Diabetes 2013; 62:1612-22. [PMID: 23382449 PMCID: PMC3636641 DOI: 10.2337/db12-0347] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We evaluated the role of ATP-sensitive K⁺ (K(ATP)) channels, somatostatin, and Zn²⁺ in the control of glucagon secretion from mouse islets. Switching from 1 to 7 mmol/L glucose inhibited glucagon release. Diazoxide did not reverse the glucagonostatic effect of glucose. Tolbutamide decreased glucagon secretion at 1 mmol/L glucose (G1) but stimulated it at 7 mmol/L glucose (G7). The reduced glucagon secretion produced by high concentrations of tolbutamide or diazoxide, or disruption of K(ATP) channels (Sur1(-/-) mice) at G1 could be inhibited further by G7. Removal of the somatostatin paracrine influence (Sst(-/-) mice or pretreatement with pertussis toxin) strongly increased glucagon release, did not prevent the glucagonostatic effect of G7, and unmasked a marked glucagonotropic effect of tolbutamide. Glucose inhibited glucagon release in the absence of functional K(ATP) channels and somatostatin signaling. Knockout of the Zn²⁺ transporter ZnT8 (ZnT8(-/-) mice) did not prevent the glucagonostatic effect of glucose. In conclusion, glucose can inhibit glucagon release independently of Zn²⁺, K(ATP) channels, and somatostatin. Closure of K(ATP) channels controls glucagon secretion by two mechanisms, a direct stimulation of α-cells and an indirect inhibition via somatostatin released from δ-cells. The net effect on glucagon release results from a balance between both effects.
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Affiliation(s)
- Rui Cheng-Xue
- Pôle d’Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Ana Gómez-Ruiz
- Pôle d’Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Nancy Antoine
- Pôle d’Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Laura A. Noël
- Pôle d’Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Hee-Young Chae
- Pôle d’Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
| | - Magalie A. Ravier
- Institut de Génomique Fonctionnelle, CNRS UMR-5203, INSERM U661, Universités de Montpellier 1 et 2, Montpellier, France
| | | | - Frans C. Schuit
- Gene Expression Unit, Department of Molecular and Cellular Medicine, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Patrick Gilon
- Pôle d’Endocrinologie, Diabète et Nutrition, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium
- Corresponding author: Patrick Gilon,
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12
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Khan F, Choong WL, Du Q, Jovanović A. Real-time RT-PCR threshold cycles value for Kir6.1 from the blood correlates with parameters of vascular function: a potential for the vascular function biomarker? Biomarkers 2013; 18:221-9. [PMID: 23480296 DOI: 10.3109/1354750x.2013.770553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Abstract We examined the presence of KATP channel subunits, Kir6.1 and SUR2B, mRNAs in the blood and vascular function in healthy volunteers (41 males, 34 females). Real-time reverse transcriptase (RT)-PCR threshold cycles (Ct) was used as an indicator of mRNA levels. Baseline skin perfusion and the post-occlusion reactive hyperemia response exhibited a significant positive correlation with Ct for Kir6.1. There was no correlation between Kir6.1 Ct and brachial artery flow-mediated dilatation. Gender had no influence on relationships between blood Kir6.1 Ct and vascular function. We conclude that blood Kir6.1 mRNA levels could be potentially used as a biomarker of the vascular function.
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Affiliation(s)
- Faisel Khan
- Medical Research Institute, Division of Cardiovascular and Diabetic Medicine, Ninewells Hospital & Medical School, University of Dundee, Dundee DD1 9SY, UK
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13
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Abstract
BACKGROUND Congenital hyperinsulinism (CHI) is a clinically heterogeneous condition. Mutations in eight genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A and HNF1A) are known to cause CHI. AIM To characterise the clinical and molecular aspects of a large cohort of patients with CHI. METHODOLOGY Three hundred patients were recruited and clinical information was collected before genotyping. ABCC8 and KCNJ11 genes were analysed in all patients. Mutations in GLUD1, HADH, GCK and HNF4A genes were sought in patients with diazoxide-responsive CHI with hyperammonaemia (GLUD1), raised 3-hydroxybutyrylcarnitine and/or consanguinity (HADH), positive family history (GCK) or when CHI was diagnosed within the first week of life (HNF4A). RESULTS Mutations were identified in 136/300 patients (45.3%). Mutations in ABCC8/KCNJ11 were the commonest genetic cause identified (n=109, 36.3%). Among diazoxide-unresponsive patients (n=105), mutations in ABCC8/KCNJ11 were identified in 92 (87.6%) patients, of whom 63 patients had recessively inherited mutations while four patients had dominantly inherited mutations. A paternal mutation in the ABCC8/KCNJ11 genes was identified in 23 diazoxide-unresponsive patients, of whom six had diffuse disease. Among the diazoxide-responsive patients (n=183), mutations were identified in 41 patients (22.4%). These include mutations in ABCC8/KCNJ11 (n=15), HNF4A (n=7), GLUD1 (n=16) and HADH (n=3). CONCLUSIONS A genetic diagnosis was made for 45.3% of patients in this large series. Mutations in the ABCC8 gene were the commonest identifiable cause. The vast majority of patients with diazoxide-responsive CHI (77.6%) had no identifiable mutations, suggesting other genetic and/or environmental mechanisms.
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Affiliation(s)
| | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical SchoolExeter, EX2 5DWUK
| | | | - Julian P Shield
- Department of Child Health, Bristol Royal Hospital for ChildrenBristol, BS2 8BJUK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical SchoolExeter, EX2 5DWUK
| | - Khalid Hussain
- (Correspondence should be addressed to K Hussain who is now at Molecular Genetics Unit, Developmental Endocrinology Research Group, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK; )
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14
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Ballantyne T, Du Q, Jovanović S, Neemo A, Holmes R, Sinha S, Jovanović A. Testosterone protects female embryonic heart H9c2 cells against severe metabolic stress by activating estrogen receptors and up-regulating IES SUR2B. Int J Biochem Cell Biol 2013; 45:283-91. [PMID: 23085378 PMCID: PMC3573229 DOI: 10.1016/j.biocel.2012.10.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 10/11/2012] [Accepted: 10/12/2012] [Indexed: 11/02/2022]
Abstract
A recent clinical study demonstrated that a testosterone supplementation improves functional capacity in elderly female patients suffering from heart failure. These findings prompted us to consider possible mechanisms of testosterone-induced cardioprotection in females. To address this question we have used a pure female population of rat heart embryonic H9c2 cells. Pre-treatment of cells with testosterone for 24h significantly increased survival of H9c2 cells exposed to 2,4-dinitrophenol (DNP), an inhibitor of oxidative phosphorylation. These cells expressed low level of androgen receptors and the effect of testosterone was not modified by hydroxyflutamide, an antagonist of androgen receptor. In contrast, cyclohexamide, an inhibitor of protein biosynthesis, and tamoxifene, a partial agonist of estrogen receptors, abolished cardioprotection afforded by testosterone. In addition, finasteride, an inhibitor of 5α-reductase, and anastrazole, an inhibitor of α-aromatase, also blocked testosterone-induced cytoprotection. Real time RT-PCR revealed that testosterone did not regulate the expression of nine subunits and accessory proteins of sarcolemmal ATP-sensitive K(+) (K(ATP)) channels. On the other hand, testosterone, as well as 17β-estradiol, up-regulated a putative mitochondrial K(ATP) channel subunit, mitochondrial sulfonylurea receptor 2B intraexonics splice variant (IES SUR2B), without affecting expression of IES SUR2A. Tamoxifene inhibited testosterone-induced up-regulation of IES SUR2B without affecting IES SUR2A. In conclusion, this study has shown that testosterone protect female embryonic heart H9c2 cells against severe metabolic stress by its conversion into metabolites that activate estrogen receptors and up-regulate IES SUR2B.
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Affiliation(s)
| | | | | | | | | | | | - Aleksandar Jovanović
- Medical Research Institute, Division of Cardiovascular & Diabetes Medicine, Ninewells Hospital & Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
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15
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Adachi H, Takahashi I, Higashimoto K, Tsuchida S, Noguchi A, Tamura H, Arai H, Ito T, Masue M, Nishibori H, Takahashi T, Soejima H. Congenital hyperinsulinism in an infant with paternal uniparental disomy on chromosome 11p15: few clinical features suggestive of Beckwith-Wiedemann syndrome. Endocr J 2013. [PMID: 23197114 DOI: 10.1507/endocrj.ej12-0242] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Beckwith-Wiedemann syndrome (BWS) is the most common congenital overgrowth syndrome involving tumor predisposition. BWS is caused by various epigenetic or genetic alterations that disrupt the imprinted genes on chromosome 11p15.5 and the clinical findings of BWS are highly variable. Hyperinsulinemic hypoglycemia is reported in about half of all babies with BWS. We identified an infant with diazoxide-unresponsive congenital hyperinsulinism (HI) without any apparent clinical features suggestive of BWS, but diagnosed BWS by molecular testing. The patient developed severe hyperinsulinemic hypoglycemia within a few hours after birth, with macrosomia and mild hydronephrosis. We excluded mutations in the K(ATP) channel genes on chromosome 11p15.1, but found a rare homozygous single nucleotide polymorphism (SNP) of ABCC8. Parental SNP pattern suggested paternal uniparetal disomy in this region. By microsatellite marker analysis on chromosome 11p15, we could diagnose BWS due to the mosaic of paternal uniparental disomy. Our case suggests that some HI of unknown genetic etiology could involve undiagnosed BWS with no apparent clinical features, which might be diagnosed only by molecular testing.
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Affiliation(s)
- Hiroyuki Adachi
- Department of Pediatrics, Akita University Graduate School of Medicine, Akita 010-8543, Japan
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16
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Allebrandt KV, Amin N, Müller-Myhsok B, Esko T, Teder-Laving M, Azevedo RVDM, Hayward C, van Mill J, Vogelzangs N, Green EW, Melville SA, Lichtner P, Wichmann HE, Oostra BA, Janssens ACJW, Campbell H, Wilson JF, Hicks AA, Pramstaller PP, Dogas Z, Rudan I, Merrow M, Penninx B, Kyriacou CP, Metspalu A, van Duijn CM, Meitinger T, Roenneberg T. A K(ATP) channel gene effect on sleep duration: from genome-wide association studies to function in Drosophila. Mol Psychiatry 2013; 18:122-32. [PMID: 22105623 DOI: 10.1038/mp.2011.142] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 09/01/2011] [Accepted: 09/27/2011] [Indexed: 11/08/2022]
Abstract
Humans sleep approximately a third of their lifetime. The observation that individuals with either long or short sleep duration show associations with metabolic syndrome and psychiatric disorders suggests that the length of sleep is adaptive. Although sleep duration can be influenced by photoperiod (season) and phase of entrainment (chronotype), human familial sleep disorders indicate that there is a strong genetic modulation of sleep. Therefore, we conducted high-density genome-wide association studies for sleep duration in seven European populations (N=4251). We identified an intronic variant (rs11046205; P=3.99 × 10(-8)) in the ABCC9 gene that explains ≈5% of the variation in sleep duration. An influence of season and chronotype on sleep duration was solely observed in the replication sample (N=5949). Meta-analysis of the associations found in a subgroup of the replication sample, chosen for season of entry and chronotype, together with the discovery results showed genome-wide significance. RNA interference knockdown experiments of the conserved ABCC9 homologue in Drosophila neurons renders flies sleepless during the first 3 h of the night. ABCC9 encodes an ATP-sensitive potassium channel subunit (SUR2), serving as a sensor of intracellular energy metabolism.
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Affiliation(s)
- K V Allebrandt
- Institute of Medical Psychology, Ludwig-Maximilians-University, Munich, Germany
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17
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Faletra F, Snider K, Shyng SL, Bruno I, Athanasakis E, Gasparini P, Dionisi-Vici C, Ventura A, Zhou Q, Stanley CA, Burlina A. Co-inheritance of two ABCC8 mutations causing an unresponsive congenital hyperinsulinism: clinical and functional characterization of two novel ABCC8 mutations. Gene 2012; 516:122-5. [PMID: 23266803 DOI: 10.1016/j.gene.2012.12.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 12/03/2012] [Indexed: 11/19/2022]
Abstract
Congenital hyperinsulinism (CHI) occurs as a consequence of unregulated insulin secretion from the pancreatic beta-cells. Severe recessive mutations and milder dominant mutations have been described in the ABCC8 and KCNJ11 genes encoding SUR1 and Kir6.2 subunits of the beta-cell ATP-sensitive K(+) channel. Here we report two patients with CHI unresponsive to medical therapy with diazoxide. Sequencing analysis identified a compound heterozygous mutation in ABCC8 in both patients. The first one is a carrier for the known mild dominant mutation p.Glu1506Lys jointly with the novel mutation p.Glu1323Lys. The second carries the p.Glu1323Lys mutation and a second novel mutation, p.Met1394Arg. Functional studies of both novel alleles showed reduced or null cell surface expression, typical of recessive mutations. Compound heterozygous mutations in congenital hyperinsulinism result in complex interactions. Studying these mechanisms can improve the knowledge of this disease and modify its therapy.
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Affiliation(s)
- Flavio Faletra
- Medical Genetics, Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy.
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Abstract
Monogenic diabetes constitutes a heterogeneous group of single gene disorders. The molecular background and clinical picture of many of these diseases have been described. While each of these forms is much less prevalent than multifactorial type 1 and type 2 diabetes mellitus (T2DM), together they affect millions of patients worldwide. Genetic diagnosis, which has become widely available, is of great clinical importance for patients with single gene diabetes. It helps to fully understand the pathophysiology of the disease, tailor the optimal hypoglycemic treatment, and define the prognosis for the entire family. Monogenic diabetes forms can be divided into 2 large groups, resulting from impaired insulin secretion or from an abnormal response to insulin. There are several lessons we have been taught by single-gene diabetes. We learned that the gene responsible for the occurrence of diabetes can be identified if an appropriate search strategy is used. In addition, discoveries of genes responsible for monogenic disorders pointed to them as susceptibility candidates for T2DM. Moreover, establishing that some families of proteins or biological pathways, such as transcription factors or potassium channel subunits, are involved in monogenic diabetes sparked research on their involvement in multifactorial diabetes. Finally, the example of single gene diabetes, particularly HNF1A MODY and permanent neonatal diabetes associated with the KCNJ11 and ABCC8 genes, all efficiently controlled on sulfonylurea, inspires us to continue the efforts to tailor individual treatment for T2DM patients. In this review paper, we summarize the impact of single gene disease discoveries on diabetes research and clinical practice.
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Affiliation(s)
- Tomasz Klupa
- Department of Metabolic Diseases, Jagiellonian University, Medical College, 15 Kopernika Street, 31-501 Krakow, Poland
- University Hospital, Krakow, Poland
| | - Jan Skupien
- Section on Genetics and Epidemiology, Joslin Diabetes Centre, Harvard Medical School, Boston, MA USA
| | - Maciej T. Malecki
- Department of Metabolic Diseases, Jagiellonian University, Medical College, 15 Kopernika Street, 31-501 Krakow, Poland
- University Hospital, Krakow, Poland
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Kunte H, Busch MA, Trostdorf K, Vollnberg B, Harms L, Mehta R, Castellani RJ, Mandava P, Kent TA, Simard JM. Hemorrhagic transformation of ischemic stroke in diabetics on sulfonylureas. Ann Neurol 2012; 72:799-806. [PMID: 23280795 PMCID: PMC3539226 DOI: 10.1002/ana.23680] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/31/2012] [Accepted: 06/15/2012] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Disability or death occurs more frequently in patients with hemorrhagic transformation (HT) after ischemic stroke. In rat models of stroke, sulfonylurea (SU) drugs such as glibenclamide (adopted US name, glyburide) confer protection against swelling and HT through actions on the novel SUR1-regulated NC(Ca-ATP) channel. Here, we sought to determine whether the use of SU drugs in patients with diabetes mellitus (DM) presenting with acute ischemic stroke might influence the incidence of HT. METHODS We retrospectively analyzed data on 220 patients with DM who presented with acute ischemic stroke, 43 of whom were managed with and continued to receive SU drugs, and 177 of whom were managed without (controls). RESULTS During a median length of stay in hospital of 11 days, 20 control patients (11%) experienced symptomatic HT (sHT), whereas no patient in the SU group experienced sHT (p = 0.016). No patient in the SU group died, compared to 18 (10%) in the control group (p = 0.027). Similarly favorable outcomes were observed after matching for baseline imbalances and excluding outliers. In support of the proposed mechanism, we present a case of sHT in which an analysis of brain tissues obtained intraoperatively showed prominent upregulation of SUR1, the target of SU drugs, in microvessels and neurons. INTERPRETATION We conclude that, in diabetic patients with acute ischemic stroke, prior and continued use of SU drugs is associated with reduced sHT compared to those whose treatment regimen does not include SU drugs.
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Affiliation(s)
- Hagen Kunte
- Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Markus A. Busch
- Department of Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Katrin Trostdorf
- Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Bernd Vollnberg
- Institute of Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Lutz Harms
- Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Rupal Mehta
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rudolf J. Castellani
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Pitchaiah Mandava
- Michael E. DeBakey VA Medical Center Comprehensive Stroke Program and the Stroke Outcomes Laboratory, Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
| | - Thomas A. Kent
- Michael E. DeBakey VA Medical Center Comprehensive Stroke Program and the Stroke Outcomes Laboratory, Department of Neurology, Baylor College of Medicine, Houston, Texas, USA
| | - J. Marc Simard
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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20
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Bao Y, Sun X, Yerong Y, Shuyuan L, Yang W. Blockers of sulfonylureas receptor 1 subunits may lead to cardiac protection against isoprenaline-induced injury in obese rats. Eur J Pharmacol 2012; 690:142-8. [PMID: 22766067 DOI: 10.1016/j.ejphar.2012.06.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 02/07/2023]
Abstract
Recent studies have found that blockers of sulfonylureas receptor 1(SUR1) might have cardiac ischemic protective effects. We evaluated the effects of a selective SUR1 blocker gliclazide on cardiac function and arrhythmia after isoprenaline-induced myocardial injury in obese rats. Diet-induced obese rats received isoprenaline or saline shots subcutaneously. Gliclazide or saline was given q12 h for 48 h to rats received isoprenaline. We measured ECG and hemodynamic parameters and collected blood samples for CK-MB, glucose and lipid profile determination, and then harvested hearts for water content, histological and immunohistochemical analysis and infarct size measurements. The obese rats' hearts receiving isoprenaline-induced myocardial injury showed up-regulated SUR-1 expression in the peri-microvascular area. Obese rats receiving gliclazide lavage had less severe arrhythmia (ASI: 4.00 ± 0.61 vs. 2.14 ± 0.39, P<0.05) and myocardial edema (water percentage: 85.16 ± 0.46% vs. 81.56 ± 0.57%, P<0.05). Less infarct size (47.6 ± 12.8% vs. 32.7 ± 9.1%, P<0.05) and improved diastolic function (LVEDP: 6.86 ± 0.85% vs. 2.51 ± 1.09%, P<0.05;-(dp/dt)(max): -1663.6 ± 387.91 mmHg/s vs. -2834.8 ± 290.76 mmHg/s, P<0.05) were also observed in rats receiving gliclazide lavage. Blocking of the SUR1 thus exerts a protective effect on the isoprenaline-induced myocardial injury in obese rats. That SUR1 blocker leads to ischemic protection suggesting a critical biological role of SUR1 in regulating the function of the cardiovascular system than previously recognized under pathophysiological conditions.
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Affiliation(s)
- Yige Bao
- West China School of Medicine, Sichuan University, Chengdu, China
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21
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Odgerel Z, Lee HS, Erdenebileg N, Gandbold S, Luvsanjamba M, Sambuughin N, Sonomtseren S, Sharavdorj P, Jodov E, Altaisaikhan K, Goldfarb LG. Genetic variants in potassium channels are associated with type 2 diabetes in a Mongolian population. J Diabetes 2012; 4:238-42. [PMID: 22151254 PMCID: PMC3309067 DOI: 10.1111/j.1753-0407.2011.00177.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Recent genome-wide association studies (GWAS) have identified more than 40 common sequence variants associated with type 2 diabetes (T2D). However, the results are not always the same in populations with differing genetic backgrounds. In the present study, we evaluated a hypothesis that a North Asian population living in a geographic area with unusually harsh environmental conditions would develop unique genetic risks. METHODS A population-based association study was performed with 21 single-nucleotide polymorphisms (SNPs) in nine genes selected according to the results of GWAS conducted in other populations. The study participants included 393 full-heritage Mongolian individuals (177 diagnosed with T2D and 216 matched controls). Genotyping was performed by TaqMan methodology. RESULTS The strongest association was detected with SNPs located within the potassium channel-coding genes KCNQ1 (highest odds ratio [OR] = 1.92; P = 3.4 × 10(-5) ) and ABCC8 (OR = 1.79; P = 5 × 10(-4) ). Genetic variants identified as strongly influencing the risk of T2D in other populations (e.g. KCNJ11 or TCF7L2) did not show significant association in Mongolia. CONCLUSIONS The strongest T2D risk-associated SNPs in Mongolians are located within two of three tested potassium channel-coding genes. Accumulated variations in these genes may be related to the exposure to harsh environmental conditions.
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Affiliation(s)
- Zagaa Odgerel
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Hee S Lee
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Narnygerel Erdenebileg
- Infectious Diseases and Immunogenetics Section, Department of Transfusion Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Suren Gandbold
- National Institute of Forensic Science, Ulaanbaatar, Mongolia
| | | | | | | | | | - Erdenezul Jodov
- Health Sciences University of Mongolia, Ulaanbaatar, Mongolia
| | | | - Lev G Goldfarb
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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22
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Abstract
The Pax6 transcription factor is crucial for pancreatic α-cells. Indeed, Pax6-deficient mouse models are characterized by markedly altered α-cell differentiation. Our objective was to investigate the role of Pax6 in glucagon secretion process. We used a Pax6-deficient model in rat primary enriched-α cells with specific small interfering RNA leading to a 70% knockdown of Pax6 expression. We first showed that Pax6 knockdown decreases glucagon biosynthesis as well as glucagon release. Through physiological assays, we demonstrated that the decrease of Pax6 affects specifically acute glucagon secretion in primary α-cell in response to glucose, palmitate, and glucose-dependent insulinotropic peptide (GIP) but not the response to arginine and epinephrine. We identified in Pax6 knockdown model that genes involved in glucagon secretion such as the glucokinase (GCK), G protein-coupled receptor (GPR40), and GIP receptor (GIPR) as well as the corresponding proteins were significantly decreased whereas the insulin receptor (IR) Kir6.2/Sur1, and glucose transporter 1 genes were not affected. We demonstrated that Pax6 directly binds and activates specific elements on the promoter region of the GPR40, GCK, and GIPR genes. Finally, through site-directed mutagenesis experiments, we showed that disruption of Pax6 binding on the GCK, GPR40, and GIPR gene promoters led to specific decreases of their activities in the αTC1.9 glucagon-producing cell line. Hence our results indicate that Pax6 acts on the regulation of glucagon secretion at least through the transcriptional control of GCK, GPR40, and GIPR. We propose that Pax6 is not only critical for glucagon biosynthesis but also for glucagon secretion particularly in response to nutrients.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Cells, Cultured
- Eye Proteins/genetics
- Eye Proteins/metabolism
- Glucagon/metabolism
- Glucokinase/genetics
- Glucokinase/metabolism
- Glucose Transporter Type 1/genetics
- Glucose Transporter Type 1/metabolism
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Immunoprecipitation
- Mutagenesis, Site-Directed
- PAX6 Transcription Factor
- Paired Box Transcription Factors/genetics
- Paired Box Transcription Factors/metabolism
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Promoter Regions, Genetic/genetics
- Protein Binding
- Rats
- Receptor, Insulin/genetics
- Receptor, Insulin/metabolism
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Gastrointestinal Hormone/genetics
- Receptors, Gastrointestinal Hormone/metabolism
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Sulfonylurea Receptors
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Affiliation(s)
- Yvan Gosmain
- Diabetes Unit, University Hospital, University of Geneva Medical School, 1211 Geneva 14, Switzerland.
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Abstract
Hemorrhagic transformation (HT) associated with recombinant tissue plasminogen activator (rt-PA) complicates and limits its use in stroke. Here, we provide a focused review on the involvement of matrix metalloproteinase 9 (MMP-9) in rt-PA-associated HT in cerebral ischemia, and we review emerging evidence that the selective inhibitor of the sulfonylurea receptor 1 (Sur1), glibenclamide (U.S. adopted name, glyburide), may provide protection against rt-PA-associated HT in cerebral ischemia. Glyburide inhibits activation of MMP-9, ameliorates edema formation, swelling, and symptomatic hemorrhagic transformation, and improves preclinical outcomes in several clinically relevant models of stroke, both without and with rt-PA treatment. A retrospective clinical study comparing outcomes in diabetic patients with stroke treated with rt-PA showed that those who were previously on and were maintained on a sulfonylurea fared significantly better than those whose diabetes was managed without sulfonylureas. Inhibition of Sur1 with injectable glyburide holds promise for ameliorating rt-PA-associated HT in stroke.
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Affiliation(s)
- J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA.
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Fatima N, Schooley JF, Claycomb WC, Flagg TP. Promoter DNA methylation regulates murine SUR1 (Abcc8) and SUR2 (Abcc9) expression in HL-1 cardiomyocytes. PLoS One 2012; 7:e41533. [PMID: 22844491 PMCID: PMC3402388 DOI: 10.1371/journal.pone.0041533] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 06/27/2012] [Indexed: 01/28/2023] Open
Abstract
Two mammalian genes encode the SURx (SUR1, Abcc8 and SUR2, Abcc9) subunits that combine with Kir6.2 (Kcnj11) subunits to form the ATP-sensitive potassium (KATP) channel in cardiac myocytes. Different isoform combinations endow the channel with distinct physiological and pharmacological properties, and we have recently reported that the molecular composition of sarcolemmal KATP channels is chamber specific in the mouse heart. KATP channel composition is determined by what subunits are expressed in a cell or tissue. In the present study, we explore the role of CpG methylation in regulating SUR1 and SUR2 expression. In HL-1 cardiomyocytes, as in atrial myocytes, SUR1 expression is markedly greater than SUR2. Consistent with CpG methylation-dependent silencing of SUR2 expression, bisulfite sequencing of genomic DNA isolated from HL-1 cells demonstrates that 57.6% of the CpGs in the promoter region of the SUR2 gene are methylated, compared with 0.14% of the the CpG residues in the SUR1 sequence. Moreover, treatment with 10 µM 5-aza-2'-deoxycytidine (Aza-dC) significantly increased both the unmethylated fraction of the SUR2 CpG island and mRNA expression. However, we cannot rule out additional mechanisms of Aza-dC action, as Aza-dC also causes a decrease in SUR1 expression and lower doses of Aza-dC do not alter the unmethylated DNA fraction but do elicit a small increase in SUR2 expression. The conclusion that DNA methylation alone is not the only regulator of SUR subunit expression is also consistent with observations in native myocytes, where the CpG islands of both SUR genes are essentially unmethylated in both atrial and ventricular myocytes. Collectively, these data demonstrate the potential for CpG methylation to regulate SURx subunit expression and raises the possibility that regulated or aberrant CpG methylation might play a role in controlling channel structure and function under different physiological conditions or different species.
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Affiliation(s)
- Naheed Fatima
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, United States of America
| | - James F. Schooley
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, United States of America
| | - Willliam C. Claycomb
- Department of Biochemistry and Molecular Biology, LSU Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Thomas P. Flagg
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hebert School of Medicine, Bethesda, Maryland, United States of America
- * E-mail:
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25
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Nguyen KH, Ta TN, Pham THM, Nguyen QT, Pham HD, Mishra S, Nyomba BLG. Nuciferine stimulates insulin secretion from beta cells-an in vitro comparison with glibenclamide. J Ethnopharmacol 2012; 142:488-495. [PMID: 22633982 DOI: 10.1016/j.jep.2012.05.024] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 05/11/2012] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Several Asian plants are known for their anti-diabetic properties and produce alkaloids and flavonoids that may stimulate insulin secretion. MATERIALS AND METHODS Using Vietnamese plants (Nelumbo nucifera, Gynostemma pentaphyllum, Smilax glabra, and Stemona tuberosa), we extracted two alkaloids (neotuberostemonine, nuciferine) and four flavonoids (astilbin, engeletin, smitilbin, and 3,5,3'-trihydroxy-7,4'-dimethoxyflavone), and studied their insulin stimulatory effects. RESULTS Nuciferine, extracted from Nelumbo nucifera, stimulated both phases of insulin secretion in isolated islets, whereas the other compounds had no effect. The effect of nuciferine was totally abolished by diazoxide and nimodipine, and diminished by protein kinase A and protein kinase C inhibition. Nuciferine and potassium had additive effects on insulin secretion. Nuciferine also stimulated insulin secretion in INS-1E cells at both 3.3 and 16.7 mM glucose concentrations. Compared with glibenclamide, nuciferine had a stronger effect on insulin secretion and less beta-cell toxicity. However, nuciferine did not compete with glibenclamide for binding to the sulfonylurea receptor. CONCLUSIONS Among several compounds extracted from anti-diabetic plants, nuciferine was found to stimulate insulin secretion by closing potassium-adenosine triphosphate channels, explaining anti-diabetic effects of Nelumbo nucifera.
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Affiliation(s)
- K Hoa Nguyen
- Department of Physiology, University of Manitoba, Winnipeg, MB, Canada R3E3P4
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26
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Ooi HL, Wu LL. Three cases of permanent neonatal diabetes mellitus: genotypes and management outcome. Singapore Med J 2012; 53:e142-e144. [PMID: 22815030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Neonatal diabetes mellitus (DM) is defined as insulin-requiring DM in the first six months of life. Unlike type 1 DM, it is a monogenic disorder resulting from a de novo mutation in the genes involved in the development of the pancreas, β-cell mass or secretory function. The majority of neonatal DM cases are caused by a heterozygous activating mutation in the KCNJ11 or ABCC8 genes that encode the Kir6.2 and SUR1 protein subunits, respectively, in the KATP channel. Sulphonylurea, a KATP channel inhibitor, can restore insulin secretion, hence offering an attractive alternative to insulin therapy. We report three cases of neonatal DM and their genetic mutations. Two patients were successfully switched over to sulphonylurea monotherapy with resultant improvement in the quality of life and a more stable blood glucose profile. Patients with neonatal DM should undergo genetic evaluation. For patients with KCNJ11 and ABCC8 gene mutation, oral sulphonylurea should be considered.
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Affiliation(s)
- Hooi Leng Ooi
- Paediatric Endocrinology Unit, Department of Paediatrics, University Kebangsaan Malaysia Medical Centre, Jalan Yaacob Latif, Bandar Tun Razak, Cheras 56000, Kuala Lumpur, Malaysia.
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27
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van Bon BWM, Gilissen C, Grange DK, Hennekam RCM, Kayserili H, Engels H, Reutter H, Ostergaard JR, Morava E, Tsiakas K, Isidor B, Le Merrer M, Eser M, Wieskamp N, de Vries P, Steehouwer M, Veltman JA, Robertson SP, Brunner HG, de Vries BBA, Hoischen A. Cantú syndrome is caused by mutations in ABCC9. Am J Hum Genet 2012; 90:1094-101. [PMID: 22608503 DOI: 10.1016/j.ajhg.2012.04.014] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 04/12/2012] [Accepted: 04/20/2012] [Indexed: 01/08/2023] Open
Abstract
Cantú syndrome is a rare disorder characterized by congenital hypertrichosis, neonatal macrosomia, a distinct osteochondrodysplasia, and cardiomegaly. Using an exome-sequencing approach applied to one proband-parent trio and three unrelated single cases, we identified heterozygous mutations in ABCC9 in all probands. With the inclusion of the remaining cohort of ten individuals with Cantú syndrome, a total of eleven mutations in ABCC9 were found. The de novo occurrence in all six simplex cases in our cohort substantiates the presence of a dominant disease mechanism. All mutations were missense, and several mutations affect Arg1154. This mutation hot spot lies within the second type 1 transmembrane region of this ATP-binding cassette transporter protein, which may suggest an activating mutation. ABCC9 encodes the sulfonylurea receptor (SUR) that forms ATP-sensitive potassium channels (K(ATP) channels) originally shown in cardiac, skeletal, and smooth muscle. Previously, loss-of-function mutations in this gene have been associated with idiopathic dilated cardiomyopathy type 10 (CMD10). These findings identify the genetic basis of Cantú syndrome and suggest that this is a new member of the potassium channelopathies.
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Affiliation(s)
- Bregje W M van Bon
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, The Netherlands
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29
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Lynch CJ, Zhou Q, Shyng SL, Heal DJ, Cheetham SC, Dickinson K, Gregory P, Firnges M, Nordheim U, Goshorn S, Reiche D, Turski L, Antel J. Some cannabinoid receptor ligands and their distomers are direct-acting openers of SUR1 K(ATP) channels. Am J Physiol Endocrinol Metab 2012; 302:E540-51. [PMID: 22167524 PMCID: PMC3311290 DOI: 10.1152/ajpendo.00250.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Here, we examined the chronic effects of two cannabinoid receptor-1 (CB1) inverse agonists, rimonabant and ibipinabant, in hyperinsulinemic Zucker rats to determine their chronic effects on insulinemia. Rimonabant and ibipinabant (10 mg·kg⁻¹·day⁻¹) elicited body weight-independent improvements in insulinemia and glycemia during 10 wk of chronic treatment. To elucidate the mechanism of insulin lowering, acute in vivo and in vitro studies were then performed. Surprisingly, chronic treatment was not required for insulin lowering. In acute in vivo and in vitro studies, the CB1 inverse agonists exhibited acute K channel opener (KCO; e.g., diazoxide and NN414)-like effects on glucose tolerance and glucose-stimulated insulin secretion (GSIS) with approximately fivefold better potency than diazoxide. Followup studies implied that these effects were inconsistent with a CB1-mediated mechanism. Thus effects of several CB1 agonists, inverse agonists, and distomers during GTTs or GSIS studies using perifused rat islets were unpredictable from their known CB1 activities. In vivo rimonabant and ibipinabant caused glucose intolerance in CB1 but not SUR1-KO mice. Electrophysiological studies indicated that, compared with diazoxide, 3 μM rimonabant and ibipinabant are partial agonists for K channel opening. Partial agonism was consistent with data from radioligand binding assays designed to detect SUR1 K(ATP) KCOs where rimonabant and ibipinabant allosterically regulated ³H-glibenclamide-specific binding in the presence of MgATP, as did diazoxide and NN414. Our findings indicate that some CB1 ligands may directly bind and allosterically regulate Kir6.2/SUR1 K(ATP) channels like other KCOs. This mechanism appears to be compatible with and may contribute to their acute and chronic effects on GSIS and insulinemia.
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MESH Headings
- ATP-Binding Cassette Transporters/agonists
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Allosteric Regulation
- Animals
- Anti-Obesity Agents/adverse effects
- Anti-Obesity Agents/chemistry
- Anti-Obesity Agents/pharmacology
- Anti-Obesity Agents/therapeutic use
- Cell Line, Transformed
- Chlorocebus aethiops
- Cricetinae
- Glucose Intolerance/chemically induced
- Glucose Intolerance/metabolism
- Humans
- Hypoglycemic Agents/adverse effects
- Hypoglycemic Agents/chemistry
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Islets of Langerhans/drug effects
- Islets of Langerhans/metabolism
- Ligands
- Male
- Membrane Transport Modulators/adverse effects
- Membrane Transport Modulators/chemistry
- Membrane Transport Modulators/pharmacology
- Membrane Transport Modulators/therapeutic use
- Mice
- Mice, Knockout
- Mice, Obese
- Potassium Channels, Inwardly Rectifying/agonists
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Rats
- Rats, Zucker
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptors, Drug/agonists
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Recombinant Proteins/agonists
- Recombinant Proteins/antagonists & inhibitors
- Recombinant Proteins/metabolism
- Stereoisomerism
- Sulfonylurea Receptors
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Affiliation(s)
- Christopher J Lynch
- Dept. of Cellular & Molecular Physiology, Pennsylvania State College of Medicine, Hershey, PA 17033, USA.
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30
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Shi WW, Yang Y, Shi Y, Jiang C. K(ATP) channel action in vascular tone regulation: from genetics to diseases. Sheng Li Xue Bao 2012; 64:1-13. [PMID: 22348955 PMCID: PMC4132831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
ATP-sensitive potassium (K(ATP)) channels are widely distributed in vasculatures, and play an important role in the vascular tone regulation. The K(ATP) channels consist of 4 pore-forming inward rectifier K(+) channel (Kir) subunits and 4 regulatory sulfonylurea receptors (SUR). The major vascular isoform of K(ATP) channels is composed of Kir6.1/SUR2B, although low levels of other subunits are also present in vascular beds. The observation from transgenic mice and humans carrying Kir6.1/SUR2B channel mutations strongly supports that normal activity of the Kir6.1/SUR2B channel is critical for cardiovascular function. The Kir6.1/SUR2B channel is regulated by intracellular ATP and ADP. The channel is a common target of several vasodilators and vasoconstrictors. Endogenous vasopressors such as arginine vasopressin and α-adrenoceptor agonists stimulate protein kinase C (PKC) and inhibit the K(ATP) channels, while vasodilators such as β-adrenoceptor agonists and vasoactive intestinal polypeptide increase K(ATP) channel activity by activating the adenylate cyclase-cAMP-protein kinase A (PKA) pathway. PKC phosphorylates a cluster of 4 serine residues at C-terminus of Kir6.1, whereas PKA acts on Ser1387 in the nucleotide binding domain 2 of SUR2B. The Kir6.1/SUR2B channel is also inhibited by oxidants including reactive oxygen species allowing vascular regulation in oxidative stress. The molecular basis underlying such a channel inhibition is likely to be mediated by S-glutathionylation at a few cysteine residues, especially Cys176, in Kir6.1. Furthermore, the channel activity is augmented in endotoxemia or septic shock, as a result of the upregulation of Kir6.1/SUR2B expression. Activation of the nuclear factor-κB dependent transcriptional mechanism contributes to the Kir6.1/SUR2B channel upregulation by lipopolysaccharides and perhaps other toll-like receptor ligands as well. In this review, we summarize the vascular K(ATP) channel regulation under physiological and pathophysiological conditions, and discuss the importance of K(ATP) channel as a potentially useful target in the treatment and prevention of cardiovascular diseases.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/physiology
- Animals
- Endotoxemia/metabolism
- Endotoxemia/physiopathology
- Humans
- KATP Channels/genetics
- KATP Channels/physiology
- Mice
- Mice, Transgenic
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/physiology
- Receptors, Drug/genetics
- Receptors, Drug/physiology
- Shock, Septic/metabolism
- Shock, Septic/physiopathology
- Sulfonylurea Receptors
- Vasoconstriction/physiology
- Vasodilation/physiology
- Vasomotor System/physiology
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Affiliation(s)
- Wei-Wei Shi
- Cardiothoracic Research Laboratory, Carlyle Fraser Heart Center, Emory University, Atlanta, GA 30308, USA.
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31
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Abstract
AIM Insulin secretagogues promote insulin release by binding to sulfonylurea receptors on pancreatic β-cells (SUR1). However, these drugs also bind to receptor isoforms on cardiac myocytes (SUR2A) and vascular smooth muscle (SUR2B). Binding to SUR2A/SUR2B may inhibit ischaemic preconditioning, an endogenous protective mechanism enabling cardiac tissue to survive periods of ischaemia. This study was designed to identify insulin secretagogues that selectively bind to SUR1 when given at therapeutic doses. METHODS Using accepted systematic review methods, three electronic databases were searched from inception to 13 June 2011. Original studies measuring the half-maximal inhibitory concentration (IC(50)) for an insulin secretagogue on K(ATP) channels using standard electrophysiological techniques were included. Steady-state concentrations (C(SS)) were estimated from the usual oral dose and clearance values for each drug. RESULTS Data were extracted from 27 studies meeting all inclusion criteria. IC(50) values for SUR1 were below those for SUR2A/SUR2B for all insulin secretagogues and addition of C(SS) values identified three distinct patterns. The C(SS) for gliclazide, glipizide, mitiglinide and nateglinide lie between IC(50) values for SUR1 and SUR2A/SUR2B, suggesting that these drugs bind selectively to pancreatic receptors. The C(SS) for glimepiride and glyburide (glibenclamide) was above IC(50) values for all three isoforms, suggesting these drugs are non-selective. Tolbutamide and repaglinide may have partial pancreatic receptor selectivity because IC(50) values for SUR1 and SUR2A/SUR2B overlapped somewhat, with the C(SS) in the midst of these values. CONCLUSIONS Insulin secretagogues display different tissue selectivity characteristics at therapeutic doses. This may translate into different levels of cardiovascular risk.
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MESH Headings
- ATP-Binding Cassette Transporters/drug effects
- ATP-Binding Cassette Transporters/metabolism
- Animals
- Carbamates/adverse effects
- Cardiovascular Diseases/chemically induced
- Cardiovascular Diseases/metabolism
- Cardiovascular Diseases/physiopathology
- Cricetinae
- Cyclohexanes/adverse effects
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Gliclazide/adverse effects
- Glipizide/adverse effects
- Glyburide/adverse effects
- Humans
- Hypoglycemic Agents/adverse effects
- Hypoglycemic Agents/pharmacology
- Ischemic Preconditioning, Myocardial
- Isoindoles/adverse effects
- Mice
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Nateglinide
- Phenylalanine/adverse effects
- Phenylalanine/analogs & derivatives
- Piperidines/adverse effects
- Potassium Channels, Inwardly Rectifying/drug effects
- Potassium Channels, Inwardly Rectifying/metabolism
- Rats
- Receptors, Drug/drug effects
- Receptors, Drug/metabolism
- Risk Factors
- Sulfonylurea Compounds/adverse effects
- Sulfonylurea Receptors
- Tolbutamide/adverse effects
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Affiliation(s)
- A S Abdelmoneim
- Faculty of Pharmacy & Pharmaceutical Sciences, 3126 Dentistry/Pharmacy Centre, University of Alberta, Edmonton, Alberta, Canada
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32
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Kapoor RR, Flanagan SE, Ellard S, Hussain K. Congenital hyperinsulinism: marked clinical heterogeneity in siblings with identical mutations in the ABCC8 gene. Clin Endocrinol (Oxf) 2012; 76:312-3. [PMID: 21851374 DOI: 10.1111/j.1365-2265.2011.04203.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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33
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Le Quan Sang KH, Arnoux JB, Mamoune A, Saint-Martin C, Bellanné-Chantelot C, Valayannopoulos V, Brassier A, Kayirangwa H, Barbier V, Broissand C, Fabreguettes JR, Charron B, Thalabard JC, de Lonlay P. Successful treatment of congenital hyperinsulinism with long-acting release octreotide. Eur J Endocrinol 2012; 166:333-9. [PMID: 22048969 DOI: 10.1530/eje-11-0874] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CONTEXT Congenital hyperinsulinism (HI) is a common cause of hypoglycemia in infancy. The medical treatment of diazoxide-unresponsive HI is based on a somatostatin analogue. OBJECTIVE This study aims at replacing three daily s.c. octreotide (Sandostatin, Novartis) injections by a single and monthly i.m. injection of long-acting release (LAR) octreotide (Sandostatin LP, Novartis) in HI patients. SUBJECTS AND METHOD LAR octreotide was injected every 4 weeks during 6 months and s.c. octreotide injections were stopped after the third injection of LAR octreotide. After this 6-month study, LAR octreotide was continued, with an average follow-up of 17 months. Ten HI pediatric patients unresponsive to diazoxide and currently treated with s.c. octreotide were included in the trial. Glycemias and other parameters (HbA1c, IGF1, height, weight, quality of life (QoL), and satisfaction) were monitored at each monthly visit. RESULTS For all ten patients, glycemias were maintained in the usual range, HbAlc (mean 5.5%; 95% CI: 4.6-6.2) and IGF1 (mean 89.7 ng/ml; 95% CI: 26-153) were unchanged. Patients gained height significantly (mean 2.7 cm; 95% CI: 1.9-3.4) and no side effect was noted during the study and the later follow-up. Plasma octreotide levels were stable under LAR octreotide. Parents' questionnaires of general satisfaction were highly positive whereas children's QoL evaluation remained unchanged. CONCLUSION In these diazoxide-unresponsive HI patients, LAR octreotide was efficient, well tolerated and contributed to a clear simplification of the medical care.
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Affiliation(s)
- Kim-Hanh Le Quan Sang
- Centre de Référence des Maladies Héréditaires du Métabolisme, Hôpital Necker-Enfants Malades, AP-HP, Université Paris Descartes, 149 Rue de Sèvres, 75015 Paris, France
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Abstract
Cerebral edema is a common finding in a variety of neurological conditions, including ischemic stroke, traumatic brain injury, ruptured cerebral aneurysm, and neoplasia. With the possible exception of neoplasia, most pathological processes leading to edema seem to share similar molecular mechanisms of edema formation. Challenges to brain-cell volume homeostasis can have dramatic consequences, given the fixed volume of the rigid skull and the effect of swelling on secondary neuronal injury. With even small changes in cellular and extracellular volume, cerebral edema can compromise regional or global cerebral blood flow and metabolism or result in compression of vital brain structures. Osmotherapy has been the mainstay of pharmacologic therapy and is typically administered as part of an escalating medical treatment algorithm that can include corticosteroids, diuretics, and pharmacological cerebral metabolic suppression. Novel treatment targets for cerebral edema include the Na(+)-K(+)-2Cl(-) co-transporter (NKCC1) and the SUR1-regulated NC(Ca-ATP) (SUR1/TRPM4) channel. These two ion channels have been demonstrated to be critical mediators of edema formation in brain-injured states. Their specific inhibitors, bumetanide and glibenclamide, respectively, are well-characterized Food and Drug Administration-approved drugs with excellent safety profiles. Directed inhibition of these ion transporters has the potential to reduce the development of cerebral edema and is currently being investigated in human clinical trials. Another class of treatment agents for cerebral edema is vasopressin receptor antagonists. Euvolemic hyponatremia is present in a myriad of neurological conditions resulting in cerebral edema. A specific antagonist of the vasopressin V1A- and V2-receptor, conivaptan, promotes water excretion while sparing electrolytes through a process known as aquaresis.
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Affiliation(s)
- Brian P. Walcott
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA
| | - Kristopher T. Kahle
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA
| | - J. Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD 21201 USA
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35
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Abstract
Type 2 diabetes mellitus (T2DM) is among the most challenging health issues of the 21st century and is associated with an alarming rise in the incidence. The pathophysiological processes that lead to development of T2DM are still unclear, however impairment in insulin secretion and/or action is clearly indicated. Type 2 diabetes is a polygenic disorder with multiple genes located on different chromosomes contributing to its susceptibility. Analysis of the genetic factors is further complicated by the fact that numerous environmental factors interact with genes to produce the disorder. Only a minority of cases of type 2 diabetes are caused by single gene defects and one example is maturity onset diabetes of the young (MODY). Previous studies indicated that variants in genes encoding the pancreatic β-cell K+ATP channel subunits Kir6.2 (KCNJ11) and SUR1 (ABCC8) are associated with neonatal diabetes. Six different types of maturity onset diabetes of young (MODY) have been identified based on characteristic gene defect. The common Pro12Ala polymorphism in peroxisome proliferator-activated receptor-γ (PPAR-γ) gene was confirmed in several studies to be associated with type 2 diabetes as well. More recently, studies reported variants within a novel gene, TCF7L2, as a putative susceptibility gene for type 2 diabetes across many ethnic backgrounds around the world. MODY patients respond better to sulphonylureas and metformin, while neonatal diabetes patients with genetic mutations can be changed from insulin to oral drugs. We hereby provide a comprehensive review on the role of genetics in type 2 diabetes mellitus.
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Affiliation(s)
- Sunil K Kota
- Department of Endocrinology, Medwin Hospital, Hyderabad, Andhra Pradesh, India.
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36
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Shemer R, Avnon Ziv C, Laiba E, Zhou Q, Gay J, Tunovsky-Babaey S, Shyng SL, Glaser B, Zangen DH. Relative expression of a dominant mutated ABCC8 allele determines the clinical manifestation of congenital hyperinsulinism. Diabetes 2012; 61:258-63. [PMID: 22106158 PMCID: PMC3237658 DOI: 10.2337/db11-0984] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Congenital hyperinsulinism (CHI) is most commonly caused by mutations in the β-cell ATP-sensitive K(+) (K(ATP)) channel genes. Severe CHI was diagnosed in a 1-day-old girl; the mother's cousin and sister had a similar phenotype. ABCC8 gene sequencing (leukocyte DNA) revealed a heterozygous, exon 37, six-base pair in-frame insertion mutation in the affected patient and aunt but also in her unaffected mother and grandfather. In expression studies using transfected COSm6 cells, mutant sulfonylurea receptor 1 (SUR1) protein was expressed on the cell surface but failed to respond to MgADP even in the heterozygous state. mRNA expression in lymphocytes determined by sequencing cDNA clones and quantifying 6FAM-labeled PCR products found that although the healthy mother predominantly expressed the normal transcript, her affected daughter, carrying the same mutant allele, primarily transcribed the mutant. The methylation pattern of the imprinting control region of chromosome 11p15.5 and ABCC8 promoter was similar for all family members. In conclusion, differences in transcript expression may determine the clinical phenotype of CHI in this maternally inherited dominant mutation. The use of peripheral lymphocytes as a peripheral window to the β-cell transcription profile can serve in resolving β-cell phenotypes. The severe, dominant-negative nature of the 1508insAS mutation suggests that it affects the functional stoichiometry of SUR1-regulated gating of K(ATP) channels.
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Affiliation(s)
- Ruth Shemer
- Department of Developmental Biology and Cancer Research, Faculty of Medicine, Hebrew University, Jerusalem, Israel
| | - Carmit Avnon Ziv
- Division of Pediatric Endocrinology, Department of Pediatrics, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Efrat Laiba
- Division of Pediatric Endocrinology, Department of Pediatrics, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Qing Zhou
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Joel Gay
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Sharona Tunovsky-Babaey
- Endocrinology and Metabolism Service, Internal Medicine Department, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Show-Ling Shyng
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Benjamin Glaser
- Endocrinology and Metabolism Service, Internal Medicine Department, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - David H. Zangen
- Division of Pediatric Endocrinology, Department of Pediatrics, Hadassah Hebrew University Medical Center, Jerusalem, Israel
- Corresponding author: David H. Zangen,
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37
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Ismail D, Kapoor RR, Smith VV, Ashworth M, Blankenstein O, Pierro A, Flanagan SE, Ellard S, Hussain K. The heterogeneity of focal forms of congenital hyperinsulinism. J Clin Endocrinol Metab 2012; 97:E94-9. [PMID: 22031516 PMCID: PMC7611920 DOI: 10.1210/jc.2011-1628] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Congenital hyperinsulinism (CHI) is a cause of persistent hypoglycemia due to unregulated insulin secretion from pancreatic β-cells. Histologically, there are two major subgroups, focal and diffuse. Focal CHI is typically unresponsive to diazoxide and can be cured with surgical removal of the focal lesion. AIMS We report on three patients with focal CHI to illustrate the marked clinical, genetic, radiological, and histological heterogeneity. METHODS AND RESULTS The first two patients had focal CHI due to a paternal (c.3992-9G→A) ABCC8 mutation. One of these patients was fully responsive to a small dose (5 mg/kg · d) of diazoxide, whereas the other patient was medically unresponsive. In both patients, the focal lesions were accurately localized preoperatively by [(18)F]dihydroxyphenylalanine (DOPA) positron emission tomography (PET) and surgically resected. The third patient had a paternally inherited ABCC8 (A1493T) mutation, and the initial [(18)F]DOPA PET scan indicated extensive uptake of DOPA in the body and tail of the pancreas. However, despite surgical resection of the body and tail, this patient continued to have severe CHI. A subsequent [(18)F]DOPA PET scan now showed markedly increased DOPA uptake in the remaining body and head of the pancreas. This focal lesion occupied virtually the whole of the pancreas. conclusions: These three cases illustrate that focal lesions even with the same genotype (c.3992-9G→A) may have a different clinical presentation and that [(18)F]DOPA PET scans in very large focal lesions may be difficult to interpret.
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Affiliation(s)
- Dunia Ismail
- Department of Endocrinology, Great Ormond Street, Hospital for Children National Health Service Trust, London, UK
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38
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Abstract
Pancreatic β-cell ATP-sensitive K(+) (K(ATP)) channels are composed of Kir6.2 and SUR1 subunits encoded by the KCNJ11 and ABCC8 genes, respectively. Although rare monogenic activating mutations in these genes cause overt neonatal diabetes, the common variants E23K (KCNJ11) and S1369A (ABCC8) form a tightly heritable haplotype that is associated with an increased susceptibility to type 2 diabetes (T2D) risk. However, the molecular mechanism(s) underlying this risk remain to be elucidated. A homology model of the SUR1 nucleotide-binding domains (NBDs) indicates that residue 1369 is in close proximity to the major MgATPase site. Therefore, we investigated the intrinsic MgATPase activity of K(ATP) channels containing these variants. Electrophysiological and biochemical techniques were used to study the MgATPase activity of recombinant human K(ATP) channels or glutathione S-transferase and NBD2 fusion proteins containing the E23/S1369 (nonrisk) or K23/A1369 (risk) variant haplotypes. K(ATP) channels containing the K23/A1369 haplotype displayed a significantly increased stimulation by guanosine triphosphate compared with the E23/S1369 haplotype (3.2- vs. 1.8-fold). This effect was dependent on the presence of the A1369 variant and was lost in the absence of Mg(2+) ions or in the presence of the MgATPase inhibitor beryllium fluoride. Direct biochemical assays also confirmed an increase in MgATPase activity in NBD2 fusion proteins containing the A1369 variant. Our findings demonstrate that the A1369 variant increases K(ATP) channel MgATPase activity, providing a plausible molecular mechanism by which the K23/A1369 haplotype increases susceptibility to T2D in humans homozygous for these variants.
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MESH Headings
- ATP-Binding Cassette Transporters/chemistry
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- ATP-Binding Cassette Transporters/physiology
- Adenosine Triphosphatases/metabolism
- Adenosine Triphosphate/metabolism
- Alanine/genetics
- Amino Acid Substitution/physiology
- Cells, Cultured
- Diabetes Mellitus, Type 2/genetics
- Enzyme Activation
- Genetic Predisposition to Disease
- Humans
- KATP Channels/chemistry
- KATP Channels/genetics
- KATP Channels/physiology
- Models, Molecular
- Polymorphism, Single Nucleotide/physiology
- Potassium Channels, Inwardly Rectifying/chemistry
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Potassium Channels, Inwardly Rectifying/physiology
- Protein Structure, Tertiary/genetics
- Receptors, Drug/chemistry
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Receptors, Drug/physiology
- Risk Factors
- Serine/genetics
- Sulfonylurea Receptors
- Transfection
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39
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Bowman P, Flanagan SE, Edghill EL, Damhuis A, Shepherd MH, Paisey R, Hattersley AT, Ellard S. Heterozygous ABCC8 mutations are a cause of MODY. Diabetologia 2012; 55:123-7. [PMID: 21989597 DOI: 10.1007/s00125-011-2319-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
Abstract
AIMS/HYPOTHESIS The ABCC8 gene encodes the sulfonylurea receptor 1 (SUR1) subunit of the pancreatic beta cell ATP-sensitive potassium (K(ATP)) channel. Inactivating mutations cause congenital hyperinsulinism (CHI) and activating mutations cause transient neonatal diabetes (TNDM) or permanent neonatal diabetes (PNDM) that can usually be treated with sulfonylureas. Sulfonylurea sensitivity is also a feature of HNF1A and HNF4A MODY, but patients referred for genetic testing with clinical features of these types of diabetes do not always have mutations in the HNF1A/4A genes. Our aim was to establish whether mutations in the ABCC8 gene cause MODY that is responsive to sulfonylurea therapy. METHODS We sequenced the ABCC8 gene in 85 patients with a BMI <30 kg/m², no family history of neonatal diabetes and who were deemed sensitive to sulfonylureas by the referring clinician or were sulfonylurea-treated. All had tested negative for mutations in the HNF1A and HNF4A genes. RESULTS ABCC8 mutations were found in seven of the 85 (8%) probands. Four patients were heterozygous for previously reported mutations and four novel mutations, E100K, G214R, Q485R and N1245D, were identified. Only four probands fulfilled MODY criteria, with two diagnosed after 25 years and one patient, who had no family history of diabetes, as a result of a proven de novo mutation. CONCLUSIONS/INTERPRETATION ABCC8 mutations can cause MODY in patients whose clinical features are similar to those with HNF1A/4A MODY. Therefore, sequencing of ABCC8 in addition to the known MODY genes should be considered if such features are present, to facilitate optimal clinical management of these patients.
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Affiliation(s)
- P Bowman
- Peninsula NIHR Clinical Research Facility, Peninsula Medical School, University of Exeter, Exeter, UK
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40
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Abstract
It is well known that sulphonylureas (SUs), commonly used in the treatment of type 2 diabetes mellitus, stimulate insulin secretion by closing ATP-sensitive K(+) (K(ATP) ) channels in pancreatic β-cells by binding to the SU receptor SUR1. SUs are now known also to activate cAMP sensor Epac2 (cAMP-GEFII) to Rap1 signalling, which promotes insulin granule exocytosis. For SUs to exert their full effects in insulin secretion, they are required to activate Epac2 as well as to inhibit the β-cell K(ATP) channels. As Epac2 is also necessary for potentiation of glucose-induced insulin secretion by cAMP-increasing agents, such as incretin, Epac2 is a target of both cAMP and SUs. The distinct effects of various SUs appear to be because of their different actions on Epac2/Rap1 signalling as well as K(ATP) channels. Differently from other SUs, gliclazide is unique in that it is specific for β-cell K(ATP) channel and does not activate Epac2.
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Affiliation(s)
- S Seino
- Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo-ku, Kobe, Japan.
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41
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Liu Y, Zhang J, Yu L, Cao F, Rao J, Li J, Jiang C, Falck JR, Jacobs ER, Zhu D. A soluble epoxide hydrolase inhibitor--8-HUDE increases pulmonary vasoconstriction through inhibition of K(ATP) channels. Pulm Pharmacol Ther 2011; 25:69-76. [PMID: 22155000 DOI: 10.1016/j.pupt.2011.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/07/2011] [Accepted: 11/26/2011] [Indexed: 11/17/2022]
Abstract
Epoxyeicosatrienoic acids (EETs), cytochrome P450-derived metabolites of arachidonic acid, are endogenously produced epoxides that act as substrates for the soluble epoxide hydrolase (sEH). Recent studies indicate that EETs increase the tension of rat pulmonary arteries (PAs), and inhibition of sEH augments hypoxic pulmonary vasoconstriction. However, the mechanisms underlying the proconstrictive effects of sEH inhibitors in pulmonary artery smooth muscle cells (PASMCs) are unclear. In the present study, we used a sEH inhibitor, 12-(3-hexylureido) dodec-8-enoic acid (8-HUDE), to examine the ionic mechanisms underlying the constriction of PAs. 8-HUDE increased the tension of rat PAs to 145% baseline in a manner which was effectively eliminated by 10 μmol/L glibenclamide, an inhibitor of ATP-sensitive K(+) (K(ATP)) channels. Whole cell currents of HEK cells transfected with Kir6.1 or SUR2B were activated by K(ATP) channel opener pinacidil, inhibited by K(ATP) channel inhibitor glibenclamide or inhibited by 8-HUDE in a concentration-dependent manner with an IC50 value of 40 uM. In addition, 8-HUDE inhibited the expression of Kir6.1 and SUR2B at both mRNA and protein level in rat PASMCs. These observations suggest that 8-HUDE exerts acute effects on K(ATP) channel activity as well as subacute effects through decreased channel expression, and these effects are, at least in part, via the Kir6.1/SUR2B channel.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- ATP-Binding Cassette Transporters/antagonists & inhibitors
- ATP-Binding Cassette Transporters/biosynthesis
- Animals
- Blotting, Western
- Cells, Cultured
- Enzyme Inhibitors/pharmacology
- Epoxide Hydrolases/antagonists & inhibitors
- Fatty Acids, Monounsaturated/pharmacology
- Female
- HEK293 Cells
- Humans
- KATP Channels/antagonists & inhibitors
- KATP Channels/biosynthesis
- Male
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/drug effects
- Patch-Clamp Techniques
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Inwardly Rectifying/antagonists & inhibitors
- Potassium Channels, Inwardly Rectifying/biosynthesis
- Pulmonary Artery/drug effects
- Pulmonary Circulation/drug effects
- Rats
- Rats, Wistar
- Real-Time Polymerase Chain Reaction
- Receptors, Drug/antagonists & inhibitors
- Receptors, Drug/biosynthesis
- Sulfonylurea Receptors
- Vasoconstriction/drug effects
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Yun Liu
- Department of Biopharmaceutical Key Laboratory of Heilongjiang Province, College of Pharmacy, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin, Heilongjiang 150081, PR China
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42
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Abstract
There has been major progress in recent years uncovering the genetic causes of diabetes presenting in the first year of life. Twenty genes have been identified to date. The most common causes accounting for the majority of cases are mutations in the genes encoding the two subunits of the ATP-sensitive potassium channel (K(ATP)), KCNJ11 and ABCC8, and the insulin gene (INS), as well as abnormalities in chromosome 6q24. Patients with activating mutations in KCNJ11 and ABCC8 can be treated with oral sulfonylureas in lieu of insulin injections. This compelling example of personalized genetic medicine leading to improved glucose regulation and quality of life may-with continued research-be repeated for other forms of neonatal diabetes in the future.
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Affiliation(s)
- Siri Atma W Greeley
- Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, Kovler Diabetes Center, The University of Chicago, Chicago, IL 60637, USA.
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43
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Abstract
Sulfonylurea receptors (SURs) form an integral part of the ATP-sensitive potassium (K(ATP)) channel complex that is present in most excitable cell types. K(ATP) channels couple cellular metabolism to electrical activity and provide a wide range of cellular functions including stimulus secretion coupling in pancreatic β cells. K(ATP) channels are composed of SURs and inward rectifier potassium channel (Kir6.x) subunits encoded by the ABCC8/9 and KCNJ8/11 genes, respectively. Recent advances in the genetics, molecular biology, and pharmacology of SURs have led to an increased understanding of these channels in the etiology and treatment of rare genetic insulin secretory disorders. Furthermore, common genetic variants in these genes are associated with an increased risk for type 2 diabetes. In this review we summarize the molecular biology, pharmacology, and physiology of SURs and K(ATP) channels, highlighting recent advances in their genetics and understanding of rare insulin secretory disorders and susceptibility to type 2 diabetes.
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Affiliation(s)
- Veronica Lang
- Department of Pharmacology, Alberta Diabetes Institute and Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta T6G 2E1, Canada
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44
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Kapoor RR, Flanagan SE, James CT, McKiernan J, Thomas AM, Harmer SC, Shield JP, Tinker A, Ellard S, Hussain K. Hyperinsulinaemic hypoglycaemia and diabetes mellitus due to dominant ABCC8/KCNJ11 mutations. Diabetologia 2011; 54:2575-83. [PMID: 21674179 PMCID: PMC3168751 DOI: 10.1007/s00125-011-2207-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/06/2011] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS Dominantly acting loss-of-function mutations in the ABCC8/KCNJ11 genes can cause mild medically responsive hyperinsulinaemic hypoglycaemia (HH). As controversy exists over whether these mutations predispose to diabetes in adulthood we investigated the prevalence of diabetes in families with dominantly inherited ATP-sensitive potassium (K(ATP)) channel mutations causing HH in the proband. METHODS We studied the phenotype of 30 mutation carriers (14 children and 16 adults) from nine families with dominant ABCC8/KCNJ11 mutations. Functional consequences of six novel missense mutations were examined by reconstituting the K(ATP) channel in human embryonic kidney 293 (HEK293) cells and evaluating the effect of drugs and metabolic poisoning on the channels using the (86)Rb flux assay. RESULTS The mutant channels all showed a lack of (86)Rb efflux on exposure to the channel agonist diazoxide or metabolic inhibition. In the families, dominant ABCC8/KCNJ11 mutations were associated with increased birthweight (median + 1.56 SD score [SDS]). Fourteen children had HH and five adults were reported with HH or hypoglycaemic episodes (63%). Progression from hypoglycaemia to diabetes mellitus occurred in two individuals. Eight adults had a history of gestational diabetes in multiple pregnancies or were diabetic (diagnosed at a median age of 31 years). Within these families, none of the 19 adults who were not carriers of the ABCC8/KCNJ11 mutation was known to be diabetic. CONCLUSIONS/INTERPRETATION The phenotype associated with dominant ABCC8/KCNJ11 mutations ranges from asymptomatic macrosomia to persistent HH in childhood. In adults, it may also be an important cause of dominantly inherited early-onset diabetes mellitus.
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Affiliation(s)
- R. R. Kapoor
- Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH UK
| | - S. E. Flanagan
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, UK
| | - C. T. James
- Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH UK
| | | | - A. M. Thomas
- BHF Laboratories, Department of Medicine, University College London, London, UK
| | - S. C. Harmer
- BHF Laboratories, Department of Medicine, University College London, London, UK
| | - J. P. Shield
- Bristol Royal Hospital for Children, Bristol, UK
| | - A. Tinker
- BHF Laboratories, Department of Medicine, University College London, London, UK
| | - S. Ellard
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, UK
| | - K. Hussain
- Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH UK
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45
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Thakur S, Flanagan SE, Ellard S, Verma IC. Congenital hyperinsulinism caused by mutations in ABCC8 (SUR1) gene. Indian Pediatr 2011; 48:733-734. [PMID: 21992908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Congenital hyperinsulinism is the most frequent cause of severe, persistent hypoglycemia in infancy and childhood. We report a 2.5 year old girl with severe congenital hyperinsulinism. Mutation analysis showed that the child is a compound heterozygote for two missense mutations in the ABCC8 gene.
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Affiliation(s)
- Seema Thakur
- Department of Genetic Medicine, Sir Ganga Ram Hospital, New Delhi, India.
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46
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Tong XL, Song J, Zhao LH, Ji HY. Kaiyuqingre formula improves insulin secretion via regulating uncoupling protein-2 and KATP channel. Chin Med J (Engl) 2011; 124:2746-2750. [PMID: 22040435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023] Open
Abstract
BACKGROUND Type 2 diabetes mellitus (T2DM) results from the complex association of insulin resistance and pancreatic β-cell failure. Recent studies have shown that patients diagnosed with T2DM present with a significant decrease in β-cell function, which can be further compromised during the progression of the disease. Several mechanisms have been shown to play a role in this process such as glucotoxicity and lipotoxicity, which contribute to accelerating insulin secretion. In this regard, Chinese medicine has a certain advantage. This experiment was performed to observe the effect of a Chinese medicine named Kaiyuqingre formula (KYQRF) on β-cell function and its mechanisms of action therein. METHODS High glucose was used to set up a model of β-cell function failure. At the same time, medicated serum of KYQRF with different doses were administered to the cells. Rosiglitazone was taken as a control to observe the changes in insulin secretion, ATP-sensitive K(+) channels (K(ATP) channel) and uncoupling protein-2 (UCP-2) in each group. RESULTS KYQRF had some effects on the insulin secretion. In a low glucose environment, no effective change in insulin secretion was observed (P > 0.05). However, insulin levels increased significantly when INS-1 cells were exposed to a high glucose environment (P < 0.05). KYQRF could also enhance cell viability (P < 0.05) in an effect similar to rosiglitazone. Although KYQRF had no effect on inwardly rectifying potassium channels (Kir6.2) (P > 0.05), it could decrease the overexpression of both UCP-2 and sulfonylurea receptor 1 (P < 0.05). CONCLUSION KYQRF can protect islet function by decreasing UCP-2 and sulfonylurea receptor 1.
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Affiliation(s)
- Xiao-lin Tong
- Department of Endocrinology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
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47
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Chao C, Liang T, Kang Y, Lin X, Xie H, Feng ZP, Gaisano HY. Syntaxin-1A inhibits KATP channels by interacting with specific conserved motifs within sulfonylurea receptor 2A. J Mol Cell Cardiol 2011; 51:790-802. [PMID: 21884702 DOI: 10.1016/j.yjmcc.2011.08.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 07/25/2011] [Accepted: 08/13/2011] [Indexed: 11/19/2022]
Abstract
We previously demonstrated that syntaxin (Syn)-1A is present in the sarcolemma of rat cardiomyocytes and binds sulfonylurea receptor (SUR) 2A nucleotide binding folds (NBFs) to inhibit ATP-sensitive potassium (K(ATP)) channel. Here, we examined for the precise domains within the NBFs of SUR2A that may interact with Syn-1A. Specifically, we tested truncated NBF protein segments encompassing the conserved motifs Walker A (W(A)), signature/Linker (L), and Walker B (W(B)). In vitro binding results indicate that the domains encompassing W(A) and L of NBF-1 and all three conserved motifs of NBF-2 bound Syn-1A. Electrophysiological studies, employing inside-out patch-clamp recordings from SUR2A/Kir6.2 expressing HEK cells and mouse cardiomyocytes, show that W(B) and L of NBF-1 and all three NBF-2 truncated protein segments reduced Syn-1A inhibition of SUR2A/K(ATP) channels. Remarkably, these same NBF-1 and -2 truncated proteins could independently disrupt the intimate FRET interactions of full length SUR2A (-mCherry) and Syn-1A (-EGFP). These results taken together indicate that Syn-1A possibly maintains inhibition of cardiac ventricular K(ATP) channels by binding to large regions of NBF-1 and NBF-2 to stabilize the NBF-1-NBF-2 heterodimer formation and prevent ATP-binding and ATP hydrolysis. Since K(ATP) channels are closely coupled to metabolic states, we postulate that these very intimate Syn-1A-SUR2A interactions are critically important for myocardial protection during stress, in which profound changes in metabolic factors (pH, ATP) could modulate these Syn-1A-SUR2A interactions.
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MESH Headings
- ATP-Binding Cassette Transporters/chemistry
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Adenosine Triphosphate/biosynthesis
- Amino Acid Motifs
- Animals
- Binding Sites
- Cell Membrane/metabolism
- Conserved Sequence
- Fluorescence Resonance Energy Transfer
- HEK293 Cells
- Humans
- KATP Channels/chemistry
- KATP Channels/genetics
- KATP Channels/metabolism
- Male
- Mice
- Microscopy, Fluorescence
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Oligopeptides/chemistry
- Oligopeptides/genetics
- Oligopeptides/metabolism
- Patch-Clamp Techniques
- Plasmids
- Potassium/metabolism
- Potassium Channels, Inwardly Rectifying/chemistry
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Protein Binding
- Protein Structure, Tertiary
- Receptors, Drug/chemistry
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Signal Transduction/physiology
- Sulfonylurea Receptors
- Syntaxin 1/chemistry
- Syntaxin 1/genetics
- Syntaxin 1/metabolism
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Affiliation(s)
- Christin Chao
- Department of Medicine, University of Toronto, Room 7368, Medical Sciences Building, Toronto, ON, Canada
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Sukhodub A, Sudhir R, Du Q, Jovanović S, Reyes S, Jovanović A. Nicotinamide-rich diet improves physical endurance by up-regulating SUR2A in the heart. J Cell Mol Med 2011; 15:1703-12. [PMID: 20731746 PMCID: PMC4373361 DOI: 10.1111/j.1582-4934.2010.01156.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 07/14/2010] [Indexed: 11/29/2022] Open
Abstract
SUR2A is an ATP-binding protein that serves as a regulatory subunit of cardioprotective ATP-sensitive K(+) (K(ATP) ) channels. Based on signalling pathway regulating SUR2A expression and SUR2A role in regulating numbers of fully assembled K(ATP) channels, we have suggested that nicotinamide-rich diet could improve physical endurance by stimulating SUR2A expression. We have found that mice on nicotinamide-rich diet significantly improved physical endurance, which was associated with significant increase in expression of SUR2A. Transgenic mice with solely overexpressed SUR2A on control diet had increased physical endurance in a similar manner as the wild-type mice on nicotinamide-rich diet. The experiments focused on action membrane potential and intracellular Ca(2+) concentration have demonstrated that increased SUR2A expression was associated with the activation of sarcolemmal K(ATP) channels and steady Ca(2+) levels in cardiomyocytes in response to β-adrenergic stimulation. In contrast, the same challenge in the wild-type was characterized by a lack of the channel activation and rise in intracellular Ca(2+) . Nicotinamide-rich diet was ineffective to increase physical endurance in mice lacking K(ATP) channels. This study has shown that nicotinamide-rich diet improves physical endurance by increasing expression of SUR2A and that this is a sole mechanism of the nicotinamide-rich diet effect. The obtained results suggest that oral nicotinamide is a regulator of SUR2A expression and has a potential as a drug that can improve physical endurance in conditions where this effect would be desirable.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Adrenergic beta-Agonists/pharmacology
- Animals
- Calcium/metabolism
- Cells, Cultured
- Diet
- Female
- Gene Expression/drug effects
- Heart Ventricles/cytology
- Heart Ventricles/drug effects
- Heart Ventricles/metabolism
- Isoproterenol/pharmacology
- Male
- Membrane Potentials/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Motor Activity/drug effects
- Myocardium/cytology
- Myocardium/metabolism
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/physiology
- Niacinamide/administration & dosage
- Niacinamide/pharmacology
- Physical Conditioning, Animal/physiology
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sulfonylurea Receptors
- Up-Regulation/drug effects
- Vitamin B Complex/administration & dosage
- Vitamin B Complex/pharmacology
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Affiliation(s)
- Andriy Sukhodub
- Division of Medical Sciences, Centre for Cardiovascular and Lung Biology, Ninewells Hospital & Medical School, University of DundeeDundee, UK
| | - Rajni Sudhir
- Division of Medical Sciences, Centre for Cardiovascular and Lung Biology, Ninewells Hospital & Medical School, University of DundeeDundee, UK
| | - Qingyou Du
- Division of Medical Sciences, Centre for Cardiovascular and Lung Biology, Ninewells Hospital & Medical School, University of DundeeDundee, UK
| | - Sofija Jovanović
- Division of Medical Sciences, Centre for Cardiovascular and Lung Biology, Ninewells Hospital & Medical School, University of DundeeDundee, UK
| | | | - Aleksandar Jovanović
- Division of Medical Sciences, Centre for Cardiovascular and Lung Biology, Ninewells Hospital & Medical School, University of DundeeDundee, UK
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Soriano S, Ripoll C, Fuentes E, Gonzalez A, Alonso-Magdalena P, Ropero AB, Quesada I, Nadal A. Regulation of K(ATP) channel by 17β-estradiol in pancreatic β-cells. Steroids 2011; 76:856-60. [PMID: 21470558 DOI: 10.1016/j.steroids.2011.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 02/17/2011] [Accepted: 03/25/2011] [Indexed: 01/05/2023]
Abstract
ATP-sensitive potassium channels (K(ATP)) regulate electrical activity and insulin secretion in pancreatic β-cells. When glucose concentration increases, the [ATP]/[ADP] ratio rises closing K(ATP) channels, and the membrane potential depolarizes, triggering insulin secretion. This pivotal role of K(ATP) channels is used not only by glucose but also by neurotransmitters, hormones and other physiological agents to modulate electrical and secretory β-cell response. In recent years, it has been demonstrated that estrogens and estrogen receptors are involved in glucose homeostasis, and that they can modulate the electrical activity and insulin secretion of pancreatic β-cells. The hormone 17β-estradiol (E2), at physiological levels, is implicated in maintaining normal insulin sensitivity for β-cell function. Long term exposure to E2 increases insulin content, insulin gene expression and insulin release via the estrogen receptor α (ERα), while rapid responses to E2 can regulate K(ATP) channels increasing cGMP levels through the estrogen receptor β (ERβ) and type A guanylate cyclase receptor (GC-A). This review summarizes the main actions of 17β-estradiol on K(ATP) channels and the subsequent insulin release in pancreatic β-cells.
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Affiliation(s)
- Sergi Soriano
- Instituto de Bioingeniería and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Universidad Miguel Hernández de Elche, 03202 Elche, Alicante, Spain.
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Russo L, Iafusco D, Brescianini S, Nocerino V, Bizzarri C, Toni S, Cerutti F, Monciotti C, Pesavento R, Iughetti L, Bernardini L, Bonfanti R, Gargantini L, Vanelli M, Aguilar-Bryan L, Stazi MA, Grasso V, Colombo C, Barbetti F. Permanent diabetes during the first year of life: multiple gene screening in 54 patients. Diabetologia 2011; 54:1693-701. [PMID: 21544516 PMCID: PMC3110270 DOI: 10.1007/s00125-011-2094-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 01/25/2011] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to investigate the genetic aetiology of permanent diabetes mellitus with onset in the first 12 months of age. METHODS We studied 46 probands with permanent, insulin-requiring diabetes with onset within the first 6 months of life (permanent neonatal diabetes mellitus [PNDM]/monogenic diabetes of infancy [MDI]) (group 1) and eight participants with diabetes diagnosed between 7 and 12 months of age (group 2). KCNJ11, INS and ABCC8 genes were sequentially sequenced in all patients. For those who were negative in the initial screening, we examined ERN1, CHGA, CHGB and NKX6-1 genes and, in selected probands, CACNA1C, GCK, FOXP3, NEUROG3 and CDK4. The incidence rate for PNDM/MDI was calculated using a database of Italian patients collected from 1995 to 2009. RESULTS In group 1 we found mutations in KCNJ11, INS and ABCC8 genes in 23 (50%), 9 (19.5%) and 4 (8.6%) patients respectively, and a single homozygous mutation in GCK (2.1%). In group 2, we identified one incidence of a KCNJ11 mutation. No genetic defects were detected in other loci. The incidence rate of PNDM/MDI in Italy is estimated to be 1:210,287. CONCLUSIONS/INTERPRETATION Genetic mutations were identified in ~75% of non-consanguineous probands with PNDM/MDI, using sequential screening of KCNJ11, INS and ABCC8 genes in infants diagnosed within the first 6 months of age. This percentage decreased to 12% in those with diabetes diagnosed between 7 and 12 months. Patients belonging to the latter group may either carry mutations in genes different from those commonly found in PNDM/MDI or have developed an early-onset form of autoimmune diabetes.
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Affiliation(s)
- L. Russo
- Laboratory of Mendelian Diabetes, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - D. Iafusco
- Department of Pediatrics, Second University of Naples, Naples, Italy
| | - S. Brescianini
- Department of Epidemiology, Istituto Superiore di Sanità, Rome, Italy
| | - V. Nocerino
- Laboratory of Mendelian Diabetes, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - C. Bizzarri
- Endocrinology Unit, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - S. Toni
- Regional Center for Juvenile Diabetes, Meyer Pediatric Hospital, Florence, Italy
| | - F. Cerutti
- Department of Pediatrics, University of Turin, Turin, Italy
| | - C. Monciotti
- Department of Pediatrics, University of Padua, Padua, Italy
| | - R. Pesavento
- Pediatric Unit, Boldrini Hospital, Thiene, Italy
| | - L. Iughetti
- Department of Pediatrics, University of Modena, Modena, Italy
| | - L. Bernardini
- Mendel Laboratory, Casa Sollievo della Sofferenza, S Giovanni, Rotondo, Italy
| | - R. Bonfanti
- Department of Pediatrics, H S Raffaele Hospital and Scientific Institute, Milan, Italy
| | - L. Gargantini
- Department of Pediatrics, Treviglio Hospital, Treviglio, Italy
| | - M. Vanelli
- Department of Pediatrics, University of Parma, Parma, Italy
| | | | - M. A. Stazi
- Department of Epidemiology, Istituto Superiore di Sanità, Rome, Italy
| | - V. Grasso
- Department of Laboratory Medicine, Tor Vergata University Hospital, Rome, Italy
| | - C. Colombo
- Laboratory of Mendelian Diabetes, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - F. Barbetti
- Laboratory of Mendelian Diabetes, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
- Department of Internal Medicine, University of Tor Vergata, Via Montpellier 1, 00134 Rome, Italy
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