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Butnariu LI, Bizim DA, Păduraru G, Păduraru L, Moisă ȘM, Popa S, Gimiga N, Ghiga G, Bădescu MC, Lupu A, Vasiliu I, Trandafir LM. Congenital Hyperinsulinism Caused by Mutations in ABCC8 Gene Associated with Early-Onset Neonatal Hypoglycemia: Genetic Heterogeneity Correlated with Phenotypic Variability. Int J Mol Sci 2024; 25:5533. [PMID: 38791571 PMCID: PMC11122115 DOI: 10.3390/ijms25105533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Congenital hyperinsulinism (CHI) is a rare disorder of glucose metabolism and is the most common cause of severe and persistent hypoglycemia (hyperinsulinemic hypoglycemia, HH) in the neonatal period and childhood. Most cases are caused by mutations in the ABCC8 and KCNJ11 genes that encode the ATP-sensitive potassium channel (KATP). We present the correlation between genetic heterogeneity and the variable phenotype in patients with early-onset HH caused by ABCC8 gene mutations. In the first patient, who presented persistent severe hypoglycemia since the first day of life, molecular genetic testing revealed the presence of a homozygous mutation in the ABCC8 gene [deletion in the ABCC8 gene c.(2390+1_2391-1)_(3329+1_3330-1)del] that correlated with a diffuse form of hyperinsulinism (the parents being healthy heterozygous carriers). In the second patient, the onset was on the third day of life with severe hypoglycemia, and genetic testing identified a heterozygous mutation in the ABCC8 gene c.1792C>T (p.Arg598*) inherited on the paternal line, which led to the diagnosis of the focal form of hyperinsulinism. To locate the focal lesions, (18)F-DOPA (3,4-dihydroxy-6-[18F]fluoro-L-phenylalanine) positron emission tomography/computed tomography (PET/CT) was recommended (an investigation that cannot be carried out in the country), but the parents refused to carry out the investigation abroad. In this case, early surgical treatment could have been curative. In addition, the second child also presented secondary adrenal insufficiency requiring replacement therapy. At the same time, she developed early recurrent seizures that required antiepileptic treatment. We emphasize the importance of molecular genetic testing for diagnosis, management and genetic counseling in patients with HH.
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Affiliation(s)
- Lăcrămioara Ionela Butnariu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Delia Andreia Bizim
- Departament of Diabetes, Saint Mary’s Emergency Children Hospital, 700309 Iasi, Romania
| | - Gabriela Păduraru
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (G.P.); (Ș.M.M.); (N.G.); (G.G.); (A.L.); (L.M.T.)
| | - Luminița Păduraru
- Department of Mother and Child, Division Neonatology, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Ștefana Maria Moisă
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (G.P.); (Ș.M.M.); (N.G.); (G.G.); (A.L.); (L.M.T.)
| | - Setalia Popa
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Nicoleta Gimiga
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (G.P.); (Ș.M.M.); (N.G.); (G.G.); (A.L.); (L.M.T.)
| | - Gabriela Ghiga
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (G.P.); (Ș.M.M.); (N.G.); (G.G.); (A.L.); (L.M.T.)
| | - Minerva Codruța Bădescu
- Department of Internal Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 16 University Street, 700115 Iasi, Romania;
| | - Ancuta Lupu
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (G.P.); (Ș.M.M.); (N.G.); (G.G.); (A.L.); (L.M.T.)
| | - Ioana Vasiliu
- Department of Morphofunctional Sciences II, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania;
| | - Laura Mihaela Trandafir
- Department of Mother and Child, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania; (G.P.); (Ș.M.M.); (N.G.); (G.G.); (A.L.); (L.M.T.)
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Mouron-Hryciuk J, Stoppa-Vaucher S, Busiah K, Bouthors T, Antoniou MC, Jacot E, Brusgaard K, Christesen HT, Hussain K, Dwyer A, Roth-Kleiner M, Hauschild M. Congenital hyperinsulinism: 2 case reports with different rare variants in ABCC8. Ann Pediatr Endocrinol Metab 2021; 26:60-65. [PMID: 32871644 PMCID: PMC8026340 DOI: 10.6065/apem.2040042.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/19/2020] [Indexed: 11/20/2022] Open
Abstract
Congenital hyperinsulinism (CHI) is a rare glucose metabolism disorder characterized by unregulated secretion of insulin that leads to hyperinsulinemic hypoglycemia (HH). Most cases are caused by mutations in the KATP-channel genes ABCC8 and KCNJ11. We report 2 patients that experienced severe HH from the first day of life. Patient 1 developed midgut volvulus after initiating diazoxide and required intestinal resection. He was subsequently managed with a high-dose octreotide and glucose-enriched diet. Consistent with diffuse type CHI by 18F-dihydroxyphenylalanine positron emission tomography-computed tomography, genetic testing revealed a homozygous ABCC8 variant, c.1801G>A, p.(Val601Ile). The rare variant was previously reported to be diazoxide-responsive, and the patient responded well to diazoxide monotherapy, with clinical remission at 2 years of age. Patient 2 responded to diazoxide with spontaneous clinical remission at 15 months of age. However, an oral glucose tolerance test at 7 years of age revealed hyperinsulinism. Genetic testing revealed that the proband and several seemingly healthy family members harbored a novel, heterozygous ABCC8 variant, c.1780T>C, p.(Ser594Pro). Genetic findings identified previously unrecognized HH in the proband's mother. The proband's uncle had been diagnosed with monogenic ABCC8-diabetes and was successfully transitioned from insulin to glibenclamide therapy. We report findings of intestinal malrotation and volvulus occurring 2 days after initiation of diazoxide treatment. We also report a novel, heterozygous ABCC8 variant in a family that exhibited cases of CHI in infancy and HH and monogenic diabetes in adult members. The cases demonstrate the importance and clinical utility of genetic analyses for informing and guiding treatment and care.
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Affiliation(s)
- Julie Mouron-Hryciuk
- Pediatric Endocrinology and Diabetology Unit, Ser vice of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Sophie Stoppa-Vaucher
- Pediatric Endocrinology and Diabetology Unit, Ser vice of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland,Department of Pediatrics, Hôpitaux Neuchâtelois, Neuchâtel, Switzerland
| | - Kanetee Busiah
- Pediatric Endocrinology and Diabetology Unit, Ser vice of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Thérèse Bouthors
- Pediatric Endocrinology and Diabetology Unit, Ser vice of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Maria Christina Antoniou
- Pediatric Endocrinology and Diabetology Unit, Ser vice of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | | | - Klaus Brusgaard
- Departement of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | | | - Khalid Hussain
- D e velopmental Endocr inology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, University College London, London, UK
| | - Andrew Dwyer
- Boston College, William F. Connell School of Nursing, Chestnut Hill, MA, USA
| | - Matthias Roth-Kleiner
- Service of Neonatology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Michael Hauschild
- Pediatric Endocrinology and Diabetology Unit, Ser vice of Pediatrics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland,Address for correspondence: Michael Hauschild Pediatric Endocrinology and Diabetology Unit, Service of Pediatrics, Lausanne University Hospital and University of Lausanne, Chemin de Montétan 16 1004 Lausanne, Switzerland
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Ngoc CTB, Dien TM, De Franco E, Ellard S, Houghton JAL, Lan NN, Thao BP, Khanh NN, Flanagan SE, Craig ME, Dung VC. Molecular Genetics, Clinical Characteristics, and Treatment Outcomes of K ATP-Channel Neonatal Diabetes Mellitus in Vietnam National Children's Hospital. Front Endocrinol (Lausanne) 2021; 12:727083. [PMID: 34566892 PMCID: PMC8458931 DOI: 10.3389/fendo.2021.727083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Neonatal diabetes mellitus (NDM) is defined as insulin-requiring persistent hyperglycemia occurring within the first 6 months of life, which can result from mutations in at least 25 different genes. Activating heterozygous mutations in genes encoding either of the subunits of the ATP-sensitive K+ channel (KATP channel; KCNJ11 or ABCC8) of the pancreatic beta cell are the most common cause of permanent NDM and the second most common cause of transient NDM. Patients with NDM caused by KATP channel mutations are sensitive to sulfonylurea (SU) treatment; therefore, their clinical management can be improved by replacing insulin with oral agents. PATIENTS AND METHODS Seventy patients were diagnosed with NDM between May 2008 and May 2021 at Vietnam National Children's Hospital, and molecular genetic testing for all genes known to cause NDM was performed at the Exeter Genomic Laboratory, UK. Patients with ABCC8 or KCNJ11 mutations were transferred from insulin to oral SU. Clinical characteristics, molecular genetics, and annual data relating to glycemic control, SU dose, severe hypoglycemia, and side effects were collected. The main outcomes of interest were SU dose, SU failure (defined as permanent reintroduction of daily insulin), and glycemic control (HbA1c). RESULTS Fifty-four of 70 patients (77%) with NDM harbored a genetic mutation and of these; 27 (50%) had activating heterozygous mutations in ABCC8 or KCNJ11. A total of 21 pathogenic mutations were identified in the 27 patients, including 13 mutations in ABCC8 and 8 mutations in KCNJ11. Overall, 51% had low birth weight (below 3rd percentile), 23 (85%) were diagnosed before 3 months of age, and 23 (85%) presented with diabetic ketoacidosis. At diagnosis, clinical and biochemical findings (mean ± SD) were pH 7.16 ± 0.16; HCO3- , 7.9 ± 7.4 mmol/L; BE, -17.9 ± 9.1 mmol/L; HbA1C, 7.98% ± 2.93%; blood glucose, 36.2 ± 12.3 mmol/L; and C-peptide median, 0.09 (range, 0-1.61 nmol/l). Twenty-six patients were successfully transferred from insulin to SU therapy. In the remaining case, remission of diabetes occurred prior to transfer. Glycemic control on SU treatment was better than on insulin treatment: HbA1c and blood glucose level decreased from 7.58% ± 4.63% and 19.04 ± 14.09 mmol/L when treated with insulin to 5.8 ± 0.94% and 6.87 ± 3.46 mmol/L when treated with SU, respectively. CONCLUSIONS This is the first case series of NDM patients with ABCC8/KCNJ11 mutations reported in Vietnam. SU is safe in the short term for these patients and more effective than insulin therapy, consistent with all studies to date. This is relevant for populations where access to and cost of insulin are problematic, reinforcing the importance of genetic testing for NDM.
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Affiliation(s)
- Can Thi Bich Ngoc
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Tran Minh Dien
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Jayne A. L. Houghton
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Nguyen Ngoc Lan
- Institute of Genome Research, Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Bui Phuong Thao
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Nguyen Ngoc Khanh
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Sarah E. Flanagan
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Maria E. Craig
- Institute of Endocrinology and Diabetes, The Children’s Hospital at Westmead/Discipline of Child and Adolescent Health, University of Sydney, Sydney, NSW, Australia
- School of Women’s and Children’s Health, University of New South Wales Medicine, Sydney, NSW, Australia
| | - Vu Chi Dung
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
- *Correspondence: Vu Chi Dung,
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Li M, Han X, Ji L. Clinical and Genetic Characteristics of ABCC8 Nonneonatal Diabetes Mellitus: A Systematic Review. J Diabetes Res 2021; 2021:9479268. [PMID: 34631896 PMCID: PMC8497126 DOI: 10.1155/2021/9479268] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Diabetes mellitus (DM) is a major chronic metabolic disease in the world, and the prevalence has been increasing rapidly in recent years. The channel of KATP plays an important role in the regulation of insulin secretion. The variants in ABCC8 gene encoding the SUR1 subunit of KATP could cause a variety of phenotypes, including neonatal diabetes mellitus (ABCC8-NDM) and ABCC8-induced nonneonatal diabetes mellitus (ABCC8-NNDM). Since the features of ABCC8-NNDM have not been elucidated, this study is aimed at concluding the genetic features and clinical characteristics. METHODS We comprehensively reviewed the literature associated with ABCC8-NNDM in the following databases: MEDLINE, PubMed, and Web of Science to investigate the features of ABCC8-NNDM. RESULTS Based on a comprehensive literature search, we found that 87 probands with ABCC8-NNDM carried 71 ABCC8 genetic variant alleles, 24% of whom carried inactivating variants, 24% carried activating variants, and the remaining 52% carried activating or inactivating variants. Nine of these variants were confirmed to be activating or inactivating through functional studies, while four variants (p.R370S, p.E1506K, p.R1418H, and p.R1420H) were confirmed to be inactivating. The phenotypes of ABCC8-NNDM were variable and could also present with early hyperinsulinemia followed by reduced insulin secretion, progressing to diabetes later. They had a relatively high risk of microvascular complications and low prevalence of nervous disease, which is different from ABCC8-NDM. CONCLUSIONS Genetic testing is essential for proper diagnosis and appropriate treatment for patients with ABCC8-NNDM. And further studies are required to determine the complex mechanism of the variants of ABCC8-NNDM.
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Affiliation(s)
- Meng Li
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center, Beijing, China 100044
| | - Xueyao Han
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center, Beijing, China 100044
| | - Linong Ji
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center, Beijing, China 100044
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Qin X, Zhong J, Lan D. The use of glimepiride for the treatment of neonatal diabetes mellitus caused by a novel mutation of the ABCC8 gene. J Pediatr Endocrinol Metab 2020; 33:1605-1608. [PMID: 33035187 DOI: 10.1515/jpem-2020-0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 08/06/2020] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes that is usually diagnosed in the first six months of life. CASE PRESENTATION We report on a male infant with neonatal diabetes who presented with diabetic ketoacidosis at two months and 16 days. A novel homozygous missense mutation (c.259T>G) was identified in the ABCC8 gene. In this case, insulin was replaced with glimepiride at a dosage of 0.49 mg/kg/day at five months, and this achieved metabolic control and satisfactory growth as observed at follow-up. CONCLUSIONS This report improves our understanding of the mutational spectrum of ABCC8, which is normally associated with NDM, and shows that the treatment regimen for this condition can be successfully switched from insulin therapy to the use of sulfonylurea.
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Affiliation(s)
- Xiao Qin
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Jingzi Zhong
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Dan Lan
- Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
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Abstract
PURPOSE OF REVIEW Obesity and diabetes have already become the second largest risk factor for cardiovascular disease. During the last decade, remarkable advances have been made in understanding the human genome's contribution to glucose homeostasis disorders and obesity. A few studies on rare mutations of candidate genes provide potential genetic targets for the treatment of diabetes and obesity. In this review, we discussed the detailed findings of these studies and the possible causalities between specific genetic variations and dysfunctions in energy or glucose homeostasis. We are optimistic that novel therapeutic strategies targeting these specific mutants for treating and preventing diabetes and obesity will be developed in the near future. RECENT FINDINGS Studies on rare genetic mutation-caused obesity or diabetes have identified potential genetic targets to decrease body weight or reduce the risk of diabetes. Rare mutations observed in lipodystrophy, obese, or diabetic human patients are promising targets in the treatment of diabetes and obesity.
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Affiliation(s)
- Bing Feng
- Pennington Biomedical Research Center, Brain Glycemic And Metabolism Control Department, Louisiana State University, 6400 Perkins Rd, Basic Science Building L2024, Baton Rouge, LA, 70808, USA
| | - Pingwen Xu
- The Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, The University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Yanlin He
- Pennington Biomedical Research Center, Brain Glycemic And Metabolism Control Department, Louisiana State University, 6400 Perkins Rd, Basic Science Building L2024, Baton Rouge, LA, 70808, USA.
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Sikimic J, McMillen TS, Bleile C, Dastvan F, Quast U, Krippeit-Drews P, Drews G, Bryan J. ATP binding without hydrolysis switches sulfonylurea receptor 1 (SUR1) to outward-facing conformations that activate K ATP channels. J Biol Chem 2018; 294:3707-3719. [PMID: 30587573 DOI: 10.1074/jbc.ra118.005236] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 12/19/2018] [Indexed: 11/06/2022] Open
Abstract
Neuroendocrine-type ATP-sensitive K+ (KATP) channels are metabolite sensors coupling membrane potential with metabolism, thereby linking insulin secretion to plasma glucose levels. They are octameric complexes, (SUR1/Kir6.2)4, comprising sulfonylurea receptor 1 (SUR1 or ABCC8) and a K+-selective inward rectifier (Kir6.2 or KCNJ11). Interactions between nucleotide-, agonist-, and antagonist-binding sites affect channel activity allosterically. Although it is hypothesized that opening these channels requires SUR1-mediated MgATP hydrolysis, we show here that ATP binding to SUR1, without hydrolysis, opens channels when nucleotide antagonism on Kir6.2 is minimized and SUR1 mutants with increased ATP affinities are used. We found that ATP binding is sufficient to switch SUR1 alone between inward- or outward-facing conformations with low or high dissociation constant, KD , values for the conformation-sensitive channel antagonist [3H]glibenclamide ([3H]GBM), indicating that ATP can act as a pure agonist. Assembly with Kir6.2 reduced SUR1's KD for [3H]GBM. This reduction required the Kir N terminus (KNtp), consistent with KNtp occupying a "transport cavity," thus positioning it to link ATP-induced SUR1 conformational changes to channel gating. Moreover, ATP/GBM site coupling was constrained in WT SUR1/WT Kir6.2 channels; ATP-bound channels had a lower KD for [3H]GBM than ATP-bound SUR1. This constraint was largely eliminated by the Q1179R neonatal diabetes-associated mutation in helix 15, suggesting that a "swapped" helix pair, 15 and 16, is part of a structural pathway connecting the ATP/GBM sites. Our results suggest that ATP binding to SUR1 biases KATP channels toward open states, consistent with SUR1 variants with lower KD values causing neonatal diabetes, whereas increased KD values cause congenital hyperinsulinism.
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Affiliation(s)
- Jelena Sikimic
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Timothy S McMillen
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
| | - Cita Bleile
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Frank Dastvan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
| | - Ulrich Quast
- Department of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, D-72074 Tübingen, Germany
| | - Peter Krippeit-Drews
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Gisela Drews
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Joseph Bryan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
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Alvarez CP, Stagljar M, Muhandiram DR, Kanelis V. Hyperinsulinism-Causing Mutations Cause Multiple Molecular Defects in SUR1 NBD1. Biochemistry 2017; 56:2400-2416. [PMID: 28346775 DOI: 10.1021/acs.biochem.6b00681] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The sulfonylurea receptor 1 (SUR1) protein forms the regulatory subunit in ATP sensitive K+ (KATP) channels in the pancreas. SUR proteins are members of the ATP binding cassette (ABC) superfamily of proteins. Binding and hydrolysis of MgATP at the SUR nucleotide binding domains (NBDs) lead to channel opening. Pancreatic KATP channels play an important role in insulin secretion. SUR1 mutations that result in increased levels of channel opening ultimately inhibit insulin secretion and lead to neonatal diabetes. In contrast, SUR1 mutations that disrupt trafficking and/or decrease gating of KATP channels cause congenital hyperinsulinism, where oversecretion of insulin occurs even in the presence of low glucose levels. Here, we present data on the effects of specific congenital hyperinsulinism-causing mutations (G716V, R842G, and K890T) located in different regions of the first nucleotide binding domain (NBD1). Nuclear magnetic resonance (NMR) and fluorescence data indicate that the K890T mutation affects residues throughout NBD1, including residues that bind MgATP, NBD2, and coupling helices. The mutations also decrease the MgATP binding affinity of NBD1. Size exclusion and NMR data indicate that the G716V and R842G mutations cause aggregation of NBD1 in vitro, possibly because of destabilization of the domain. These data describe structural characterization of SUR1 NBD1 and shed light on the underlying molecular basis of mutations that cause congenital hyperinsulinism.
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Affiliation(s)
- Claudia P Alvarez
- Department of Chemical and Physical Sciences, University of Toronto Mississauga , 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.,Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario, Canada M5S 3H6
| | - Marijana Stagljar
- Department of Chemical and Physical Sciences, University of Toronto Mississauga , 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.,Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario, Canada M5S 3H6.,Department of Cell and Systems Biology, University of Toronto , 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
| | - D Ranjith Muhandiram
- Department of Molecular Genetics, University of Toronto , 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Voula Kanelis
- Department of Chemical and Physical Sciences, University of Toronto Mississauga , 3359 Mississauga Road, Mississauga, Ontario, Canada L5L 1C6.,Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario, Canada M5S 3H6.,Department of Cell and Systems Biology, University of Toronto , 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
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Zhang Y, Pan S, Zheng X, Wan Q. Cytomembrane ATP-sensitive K + channels in neurovascular unit targets of ischemic stroke in the recovery period. Exp Ther Med 2016; 12:1055-1059. [PMID: 27446320 PMCID: PMC4950624 DOI: 10.3892/etm.2016.3373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/20/2016] [Indexed: 12/14/2022] Open
Abstract
The present study was to analyze the mechanism of cytomembrane ATP-sensitive K+ channels (KATP) in the neurovascular unit treatment of ischemic stroke in the recovery period. A total of 24 healthy adult male Wistar rats of 5–8 weeks age, weighing 160–200 g were randomly divided into the control (sham-operation group), model, KATP blocker and KATP opener groups (n=6 rats per group). Nylon cerebral artery occlusion was conducted using nylon monofilament coated with Poly-L-lysine, which was used to produce a cerebral infarction model. After feeding normally for 3 days, 5-hydroxydecanoate (40 mg/Kg), and diazoxide (40 mg/Kg) were injected to the abdominal cavity in the blocker, and opener groups, respectively. The control received an equivalent normal saline that was injected into the sham-operation and model groups. The animals were mutilated and samples were collected after 3 days. RT-PCR was used to detect the expression levels of the three subunits of KATP, i.e., kir6.1, and sulfonylurea receptor (SUR) 1 and SUR2 mRNA, as well as to calculate infarct size in tetrazolium chloride staining. The expression level of mRNA in the opener group were significantly higher, followed by the model and blocker groups, with the control group being the lowest (P<0.05). Infarct size in the opener group was markedly smaller than the model and blocker groups, and infarct size in the blocker group was significantly larger (P<0.05). Thus, the target treatment on KATP may improve the prognosis of ischemic stroke during the recovery period.
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Affiliation(s)
- Yang Zhang
- Department of Neurology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210000, P.R. China
| | - Sipei Pan
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Xiaolu Zheng
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Qi Wan
- Department of Neurology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210000, P.R. China
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