1
|
Larsen AR, Brusgaard K, Christesen HT, Detlefsen S. Genotype-histotype-phenotype correlations in hyperinsulinemic hypoglycemia. Histol Histopathol 2024; 39:817-844. [PMID: 38305063 DOI: 10.14670/hh-18-709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Hyperinsulinemic hypoglycemia (HH) of pancreatic origin includes congenital hyperinsulinism (CHI), insulinoma, insulinomatosis, and adult-onset non-insulinoma persistent hyperinsulinemic hypoglycemia syndrome (NI-PHHS). In this review, we describe the genotype-histotype-phenotype correlations in HH and their therapeutic implications. CHI can occur from birth or later on in life. Histologically, diffuse CHI shows diffuse beta cell hypertrophy with a few giant nuclei per islet of Langerhans, most frequently caused by loss-of-function mutations in ABCC8 or KCNJ11. Focal CHI is histologically characterized by focal adenomatous hyperplasia consisting of confluent hyperplastic islets, caused by a paternal ABCC8/KCNJ11 mutation combined with paternal uniparental disomy of 11p15. CHI in Beckwith-Wiedemann syndrome is caused by mosaic changes in the imprinting region 11p15.4-11p15.5, leading to segmental or diffuse overgrowth of endocrine tissue in the pancreas. Morphological mosaicism of pancreatic islets is characterized by occurence of hyperplastic (type 1) islets in one or a few lobules and small (type 2) islets in the entire pancreas. Other rare genetic causes of CHI show less characteristic or unspecific histology. HH with a predominant adult onset includes insulinomas, which are pancreatic insulin-producing endocrine neoplasms, in some cases with metastatic potential. Insulinomas occur sporadically or as part of multiple endocrine neoplasia type 1 due to MEN1 mutations. MAFA mutations may histologically lead to insulinomatosis with insulin-producing neuroendocrine microadenomas or neuroendocrine neoplasms. NI-PHHS is mainly seen in adults and shows slight histological changes in some patients, which have been defined as major and minor criteria. The genetic cause is unknown in most cases. The diagnosis of HH, as defined by genetic, histological, and phenotypic features, has important implications for patient management and outcome.
Collapse
Affiliation(s)
- Annette Rønholt Larsen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
- Steno Diabetes Center, Odense University Hospital, Odense, Denmark
| | - Klaus Brusgaard
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
- Steno Diabetes Center, Odense University Hospital, Odense, Denmark
| | - Henrik Thybo Christesen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Steno Diabetes Center, Odense University Hospital, Odense, Denmark
| | - Sönke Detlefsen
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Department of Pathology, Odense University Hospital, Odense, Denmark.
| |
Collapse
|
2
|
Li C, Juliana CA, Yuan Y, Li M, Lu M, Chen P, Boodhansingh KE, Doliba NM, Bhatti TR, Adzick NS, Stanley CA, De León DD. Phenotypic Characterization of Congenital Hyperinsulinism Due to Novel Activating Glucokinase Mutations. Diabetes 2023; 72:1809-1819. [PMID: 37725835 PMCID: PMC10658072 DOI: 10.2337/db23-0465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/10/2023] [Indexed: 09/21/2023]
Abstract
The importance of glucokinase (GK) in the regulation of insulin secretion has been highlighted by the phenotypes of individuals with activating and inactivating mutations in the glucokinase gene (GCK). Here we report 10 individuals with congenital hyperinsulinism (HI) caused by eight unique activating mutations of GCK. Six are novel and located near previously identified activating mutations sites. The first recognized episode of hypoglycemia in these patients occurred between birth and 24 years, and the severity of the phenotype was also variable. Mutant enzymes were expressed and purified for enzyme kinetics in vitro. Mutant enzymes had low glucose half-saturation concentration values and an increased enzyme activity index compared with wild-type GK. We performed functional evaluation of islets from the pancreata of three children with GCK-HI who required pancreatectomy. Basal insulin secretion in perifused GCK-HI islets was normal, and the response to glyburide was preserved. However, the threshold for glucose-stimulated insulin secretion in perifused glucokinase hyperinsulinism (GCK-HI) islets was decreased, and glucagon secretion was greatly suppressed. Our evaluation of novel GCK disease-associated mutations revealed that the detrimental effects of these mutations on glucose homeostasis can be attributed not only to a lowering of the glucose threshold of insulin secretion but also to a decreased counterregulatory glucagon secretory response. ARTICLE HIGHLIGHTS Our evaluation of six novel and two previously published activating GCK mutations revealed that the detrimental effects of these mutations on glucose homeostasis can be attributed not only to a lowering of the glucose threshold of insulin secretion but also to a decreased counterregulatory glucagon secretory response. These studies provide insights into the pathophysiology of GCK-hyperinsulinism and the dual role of glucokinase in β-cells and α-cells to regulate glucose homeostasis.
Collapse
Affiliation(s)
- Changhong Li
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Nanjing AscendRare Pharmaceutical Technology Co., Nanjing, China
| | - Christine A. Juliana
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Yue Yuan
- Nanjing AscendRare Pharmaceutical Technology Co., Nanjing, China
| | - Ming Li
- Department of Endocrinology, National Health Commission (NHC) Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Ming Lu
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Pan Chen
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Kara E. Boodhansingh
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Nicolai M. Doliba
- Institute of Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Tricia R. Bhatti
- Department of Pathology, The Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - N. Scott Adzick
- Department of Surgery, The Children’s Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Charles A. Stanley
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Diva D. De León
- Division of Endocrinology and Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| |
Collapse
|
3
|
Cho J, Horikawa Y, Oiwa Y, Hosomichi K, Yabe D, Imai T. Glucokinase Variant Proteins Are Resistant to Fasting-Induced Uridine Diphosphate Glucose-Dependent Degradation in Maturity-Onset Diabetes of the Young Type 2 Patients. Int J Mol Sci 2023; 24:15842. [PMID: 37958824 PMCID: PMC10649437 DOI: 10.3390/ijms242115842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/27/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
We previously reported that glucokinase undergoes ubiquitination and subsequent degradation, a process mediated by cereblon, particularly in the presence of uridine diphosphate glucose (UDP-glucose). In this context, we hereby present evidence showcasing the resilience of variant glucokinase proteins of maturity-onset diabetes of the young type 2 (MODY2) against degradation and, concomitantly, their influence on insulin secretion, both in cell lines and in the afflicted MODY2 patient. Hence, glucose-1-phodphate promotes UDP-glucose production by UDP-glucose pyrophosphorylase 2; consequently, UDP-glucose-dependent glucokinase degradation may occur during fasting. Next, we analyzed glucokinase variant proteins from MODY2 or persistent hyperinsulinemic hypoglycemia in infancy (PHHI). Among the eleven MODY2 glucokinase-mutated proteins tested, those with a lower glucose-binding affinity exhibited resistance to UDP-glucose-dependent degradation. Conversely, the glucokinaseA456V-mutated protein from PHHI had a higher glucose affinity and was sensitive to UDP-glucose-dependent degradation. Furthermore, in vitro studies involving UDP-glucose-dependent glucokinase variant proteins and insulin secretion during fasting in Japanese MODY2 patients revealed a strong correlation and a higher coefficient of determination. This suggests that UDP-glucose-dependent glucokinase degradation plays a significant role in the pathogenesis of glucose-homeostasis-related hereditary diseases, such as MODY2 and PHHI.
Collapse
Affiliation(s)
- Jaeyong Cho
- Department of Chemical Biology, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan; (J.C.); (Y.O.)
| | - Yukio Horikawa
- Departments of Diabetes, Endocrinology and Metabolism, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan; (Y.H.); (D.Y.)
| | - Yuki Oiwa
- Department of Chemical Biology, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan; (J.C.); (Y.O.)
| | - Kazuyoshi Hosomichi
- Laboratory of Computational Genomics, School of Life Science, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan;
| | - Daisuke Yabe
- Departments of Diabetes, Endocrinology and Metabolism, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan; (Y.H.); (D.Y.)
- Department of Rheumatology and Clinical Immunology, Gifu University Graduate School of Medicine, Gifu 501-1194, Japan
| | - Takeshi Imai
- Department of Chemical Biology, National Center for Geriatrics and Gerontology, Obu 474-8511, Japan; (J.C.); (Y.O.)
| |
Collapse
|
4
|
Demiral M, Çelebi H, Cander S, Yerci O, Eren E, Demirbilek H. TWO OPPOSITE PHENOTYPES OF GLUCOSE DISORDERS IN A FAMILY WITH HETEROZYGOUS P.SER453LEU (C.1358C> T) MUTATION IN THE GLUCOKINASE (GCK) GENE: MATURITY ONSET DIABETES IN YOUNG AND INSULINOMA. ACTA ENDOCRINOLOGICA (BUCHAREST, ROMANIA : 2005) 2022; 18:458-465. [PMID: 37152879 PMCID: PMC10162830 DOI: 10.4183/aeb.2022.458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Background Heterozygous gain-of-function mutations in the glucokinase (GCK) gene cause hyperinsulinaemic hypoglycaemia (GCK-HI), while loss-of-function mutations lead to a monogenic type of diabetes (GCK-MODY). We, herein, report a heterozygous GCK gene mutation in a large family with GCK-MODY and insulinoma in one individual from the same family. Patients and methods The proband, an 11-year-old male, was referred for asymptomatic mild hyperglycemia (fasting glucose:121 mg/dL) and HbA1c of 6.1%. Segregation analysis of the family revealed multiplex members with asymptomatic fasting hyperglycaemia or non-insulin-dependent diabetes and 33-year-old maternal uncle of the proband case had a history of distal pancreatectomy due to the diagnosis of insulinoma. His preoperative investigations were revealed fasting glucose of 31 mg/dL, insulin: 7µU/mL, C-peptide: 2.6 mg/dL, and a low HbA1c(4.0%) which was suggestive for recurring hypoglycaemia episodes. Post-pancreatectomy he developed mild fasting hyperglycemia (115-136 mg/dL). Results Genetic analysis revealed heterozygous p.Ser453Leu(c.1358C> T) mutation in the GCK gene in the proband. In segregation analysis, the identical heterozygous p.Ser453Leu(c.1358C> T) GCK gene mutation was detected in all of the other affected family members for whom a DNA analysis was applicable. The maternal uncle was first diagnosed with insulinoma and underwent a pancreatectomy. He also had an identical mutation in a heterozygous state. Conclusion We, to the best of our knowledge, firstly identified these two entirely distinct phenotypes of glucose metabolism, GCK-MODY and GCK-HI, due to an identical heterozygous p.Ser453Leu (c.1358C> T) mutation in the GCK. Further studies required to elucidate this new phenomenon and understanding the genotype-phenotype relationship of GCK gene mutations.
Collapse
Affiliation(s)
- M. Demiral
- Balıkesir Atatürk City Hospital, Department of Paediatric Endocrinology, Balıkesir
| | - H.B.G. Çelebi
- Balıkesir Atatürk City Hospital, Department of Medical Genetic, Balıkesir
| | - S. Cander
- Uludağ University, Department of Endocrinology, Bursa
| | - O. Yerci
- Uludağ University, Department of Pathology, Bursa
| | - E. Eren
- Uludağ University, Department of Paediatric Endocrinology, Bursa
| | - H. Demirbilek
- Hacettepe University, Faculty of Medicine, Department of Paediatric Endocrinology, Ankara, Turkey
| |
Collapse
|
5
|
Hyperinsulinemic Hypoglycemia in Three Generations of a Family with Glucokinase Activating Mutation, c.295T>C (p.Trp99Arg). Genes (Basel) 2021; 12:genes12101566. [PMID: 34680961 PMCID: PMC8535713 DOI: 10.3390/genes12101566] [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] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/26/2022] Open
Abstract
Familial Hyperinsulinemic Hypoglycemia (FHH) is a very rare disease with heterogeneous clinical manifestations. There are only a few reports of heterozygous activating mutations of glucokinase (GCK) attributable to FHH, with no reports describing effects in the course in pregnancy with affected mother/affected child. A large kindred with FHH and GCK:c.295T>C (p.Trp99Arg) pathogenic variant was identified in which four family members from three generations were affected. The clinical follow up in one clinical center lasted up to 30 years, with different times of diagnosis ranging from neonate period to adulthood. The severity of hypoglycemia was mild/severe and fasting was the trigger for hypoglycemia. Response to diazoxide varied from good, in the neonate, to moderate/poor, in childhood/adulthood; however, this was biased by poor compliance. Treatment with somatostatin analogues was discontinued due to side effects. Over time, patients developed clinical adaptation to very low glucose levels. During pregnancy, episodes of severe hypoglycemia in the first trimester were observed, which responded very well to steroids. The clinical course of the GCK:c.295T>C (p.Trp99Arg) mutation varied in the same family, with the development of clinical adaptation to very low glucose levels over time. Treatment with steroids might prevent hypoglycemia during pregnancy in an affected mother.
Collapse
|
6
|
Ang SF, Tan CSH, Chan LWT, Goh LX, Kon WYC, Lian JX, Subramanium T, Sum CF, Lim SC. Clinical experience from a regional monogenic diabetes referral centre in Singapore. Diabetes Res Clin Pract 2020; 168:108390. [PMID: 32858097 DOI: 10.1016/j.diabres.2020.108390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/06/2020] [Accepted: 08/19/2020] [Indexed: 11/30/2022]
Abstract
AIMS Monogenic diabetes (also known as maturity-onset diabetes of the young or MODY) affects a subset of individuals with young-onset diabetes. We report our diagnostic work-up experience for such individuals. METHODS Serving as a regional secondary-care diabetes centre in a multi-ethnic population, we receive referrals to evaluate MODY from endocrinologists in both public and private practice. Key criteria for consideration of genetic-testing are onset age ≤ 35, negative GAD antibody, no history of diabetic ketoacidosis, strong family history of diabetes and BMI < 32.5 kg/m2. A monogenic diabetes registry was set up since 2017 to study their disease trajectories. RESULTS We identified 30 out of 175 (17.1%) individuals with likely pathogenic/pathogenic variants. Importantly, 29 out of 30 (96.7%) occurred in clinically actionable genes. A continuous scale combining BMI, hs-CRP and HDL provided 80% (P < 0.001) diagnostic accuracy for MODY in our cohort, achieving a negative predictive value of 0.93 and sensitivity at 0.76. Subtyping MODY prior to genetic testing (if desired) will require specialist domain knowledge and additional biomarkers due to its genetic heterogeneity. CONCLUSIONS Through systematic and structured evaluation, the prevalence of MODY is non-trivial (17.1%) in a referral centre. Diagnostic algorithm combining clinical criteria and readily available biomarkers can support clinical decision for MODY genetic testing.
Collapse
Affiliation(s)
- Su Fen Ang
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore
| | - Clara S H Tan
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore
| | - Lovynn W T Chan
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore
| | - Li Xian Goh
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore
| | - Winston Y C Kon
- Department of Endocrinology, Tan Tock Seng Hospital (TTSH), Singapore
| | - Joyce X Lian
- Department of Endocrinology, Tan Tock Seng Hospital (TTSH), Singapore
| | | | - Chee Fang Sum
- Diabetes Centre, Admiralty Medical Centre (AdMC), Singapore
| | - Su Chi Lim
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore; Diabetes Centre, Admiralty Medical Centre (AdMC), Singapore; Saw Swee Hock School of Public Health, National University of Singapore (NUS), Singapore.
| |
Collapse
|
7
|
Whitticar NB, Nunemaker CS. Reducing Glucokinase Activity to Enhance Insulin Secretion: A Counterintuitive Theory to Preserve Cellular Function and Glucose Homeostasis. Front Endocrinol (Lausanne) 2020; 11:378. [PMID: 32582035 PMCID: PMC7296051 DOI: 10.3389/fendo.2020.00378] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/12/2020] [Indexed: 12/21/2022] Open
Abstract
Pancreatic beta-cells are the only cells in the body that can synthesize and secrete insulin. Through the process of glucose-stimulated insulin secretion, beta-cells release insulin into circulation, stimulating GLUT4-dependent glucose uptake into peripheral tissue. Insulin is normally secreted in pulses that promote signaling at the liver. Long before type 2 diabetes is diagnosed, beta-cells become oversensitive to glucose, causing impaired pulsatility and overstimulation in fasting levels of glucose. The resulting hypersecretion of insulin can cause poor insulin signaling and clearance at the liver, leading to hyperinsulinemia and insulin resistance. Continued overactivity can eventually lead to beta-cell exhaustion and failure at which point type 2 diabetes begins. To prevent or reverse the negative effects of overstimulation, beta-cell activity can be reduced. Clinical studies have revealed the potential of beta-cell rest to reverse new cases of diabetes, but treatments lack durable benefits. In this perspective, we propose an intervention that reduces overactive glucokinase activity in the beta-cell. Glucokinase is known as the glucose sensor of the beta-cell due to its high control over insulin secretion. Therefore, glycolytic overactivity may be responsible for hyperinsulinemia early in the disease and can be reduced to restore normal stimulus-secretion coupling. We have previously reported that reducing glucokinase activity in prediabetic mouse islets can restore pulsatility and enhance insulin secretion. Building on this counterintuitive finding, we review the importance of pulsatile insulin secretion and highlight how normalizing glucose sensing in the beta cell during prediabetic hyperinsulinemia may restore pulsatility and improve glucose homeostasis.
Collapse
Affiliation(s)
- Nicholas B. Whitticar
- Translational Biomedical Sciences Program, Graduate College, Ohio University, Athens, OH, United States
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens OH, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
| | - Craig S. Nunemaker
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens OH, United States
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States
- *Correspondence: Craig S. Nunemaker
| |
Collapse
|
8
|
Dwulet JM, Ludin NWF, Piscopio RA, Schleicher WE, Moua O, Westacott MJ, Benninger RKP. How Heterogeneity in Glucokinase and Gap-Junction Coupling Determines the Islet [Ca 2+] Response. Biophys J 2019; 117:2188-2203. [PMID: 31753287 PMCID: PMC6895742 DOI: 10.1016/j.bpj.2019.10.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/20/2019] [Accepted: 10/25/2019] [Indexed: 11/24/2022] Open
Abstract
Understanding how cell subpopulations in a tissue impact overall system function is challenging. There is extensive heterogeneity among insulin-secreting β-cells within islets of Langerhans, including their insulin secretory response and gene expression profile, and this heterogeneity can be altered in diabetes. Several studies have identified variations in nutrient sensing between β-cells, including glucokinase (GK) levels, mitochondrial function, or expression of genes important for glucose metabolism. Subpopulations of β-cells with defined electrical properties can disproportionately influence islet-wide free-calcium activity ([Ca2+]) and insulin secretion via gap-junction electrical coupling. However, it is poorly understood how subpopulations of β-cells with altered glucose metabolism may impact islet function. To address this, we utilized a multicellular computational model of the islet in which a population of cells deficient in GK activity and glucose metabolism was imposed on the islet or in which β-cells were heterogeneous in glucose metabolism and GK kinetics were altered. This included simulating GK gene (GCK) mutations that cause monogenic diabetes. We combined these approaches with experimental models in which gck was genetically deleted in a population of cells or GK was pharmacologically inhibited. In each case, we modulated gap-junction electrical coupling. Both the simulated islet and the experimental system required 30-50% of the cells to have near-normal glucose metabolism, fewer than cells with normal KATP conductance. Below this number, the islet lacked any glucose-stimulated [Ca2+] elevations. In the absence of electrical coupling, the change in [Ca2+] was more gradual. As such, electrical coupling allows a large minority of cells with normal glucose metabolism to promote glucose-stimulated [Ca2+]. If insufficient numbers of cells are present, which we predict can be caused by a subset of GCK mutations that cause monogenic diabetes, electrical coupling exacerbates [Ca2+] suppression. This demonstrates precisely how metabolically heterogeneous β-cell populations interact to impact islet function.
Collapse
Affiliation(s)
- JaeAnn M Dwulet
- Department of Bioengineering, University of Colorado, Aurora, Colorado
| | - Nurin W F Ludin
- Department of Bioengineering, University of Colorado, Aurora, Colorado
| | - Robert A Piscopio
- Department of Bioengineering, University of Colorado, Aurora, Colorado
| | | | - Ong Moua
- Department of Bioengineering, University of Colorado, Aurora, Colorado
| | | | - Richard K P Benninger
- Department of Bioengineering, University of Colorado, Aurora, Colorado; Barbara Davis Center for Childhood Diabetes, Anschutz Medical Campus, University of Colorado, Aurora, Colorado.
| |
Collapse
|
9
|
Ping F, Wang Z, Xiao X. Clinical and enzymatic phenotypes in congenital hyperinsulinemic hypoglycemia due to glucokinase-activating mutations: A report of two cases and a brief overview of the literature. J Diabetes Investig 2019; 10:1454-1462. [PMID: 31094068 PMCID: PMC6825936 DOI: 10.1111/jdi.13072] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 04/10/2019] [Accepted: 04/26/2019] [Indexed: 01/06/2023] Open
Abstract
AIMS/INTRODUCTION The principal aim of this study was to investigate the clinical, genetic and functional characteristics of two cases of congenital hyperinsulinism (CHI) caused by glucokinase (GCK) mutations in young patients. MATERIALS AND METHODS Novel mutations were detected by CHI next-generation sequencing, and the kinetic parameters and thermal stability of recombinant wild-type and mutant glucokinase were determined in vitro. In addition, 18 naturally occurring GCK-CHI mutations reported previously were also summarized. RESULTS A de novo mutation (M197V) was found in a 17-year-old male with an epilepsy history, whereas an autosomal dominant mutation (K90R) was found in a 20-year-old female with inherited asymptomatic hypoglycemia. Kinetic analysis showed increased enzyme activity for both mutants (RAI 4.7 for M197V and 1.6 for K90R) and enhanced thermal stability for the M197V mutant. However, of all the GCK-CHI mutants, the increase in enzyme activity (RAI between 1.6 and 130) did not correlate strongly with the severity of hypoglycemia. The de novo group (7/19) showed distinctive phenotypes from the autosomal dominant group (12/19), such as a higher proportion of diazoxide unresponsiveness (28.6% vs 0%), a higher incidence of macrosomia (85.7% vs 40%) and a rarer incidence of adulthood onset (0% vs 25%). CONCLUSIONS The clinical phenotypes of GCK-CHIs were highly heterogeneous. We have identified two novel GCK-CHI mutations in young patients and investigated their pathogenicity by enzyme kinetic analysis, which expanded the spectrum of this rare disease.
Collapse
Affiliation(s)
- Fan Ping
- NHC Key Laboratory of EndocrinologyDepartment of EndocrinologyPeking Union Medical College HospitalChinese Academy of Medical Science and Peking UnionBeijingChina
| | - Zhixin Wang
- Department of EndocrinologyBeijing Jishuitan HospitalBeijingChina
| | - Xinhua Xiao
- NHC Key Laboratory of EndocrinologyDepartment of EndocrinologyPeking Union Medical College HospitalChinese Academy of Medical Science and Peking UnionBeijingChina
| |
Collapse
|
10
|
Galcheva S, Demirbilek H, Al-Khawaga S, Hussain K. The Genetic and Molecular Mechanisms of Congenital Hyperinsulinism. Front Endocrinol (Lausanne) 2019; 10:111. [PMID: 30873120 PMCID: PMC6401612 DOI: 10.3389/fendo.2019.00111] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/06/2019] [Indexed: 12/13/2022] Open
Abstract
Congenital hyperinsulinism (CHI) is a heterogenous and complex disorder in which the unregulated insulin secretion from pancreatic beta-cells leads to hyperinsulinaemic hypoglycaemia. The severity of hypoglycaemia varies depending on the underlying molecular mechanism and genetic defects. The genetic and molecular causes of CHI include defects in pivotal pathways regulating the secretion of insulin from the beta-cell. Broadly these genetic defects leading to unregulated insulin secretion can be grouped into four main categories. The first group consists of defects in the pancreatic KATP channel genes (ABCC8 and KCNJ11). The second and third categories of conditions are enzymatic defects (such as GDH, GCK, HADH) and defects in transcription factors (for example HNF1α, HNF4α) leading to changes in nutrient flux into metabolic pathways which converge on insulin secretion. Lastly, a large number of genetic syndromes are now linked to hyperinsulinaemic hypoglycaemia. As the molecular and genetic basis of CHI has expanded over the last few years, this review aims to provide an up-to-date knowledge on the genetic causes of CHI.
Collapse
Affiliation(s)
- Sonya Galcheva
- Department of Paediatrics, University Hospital St. Marina, Varna Medical University, Varna, Bulgaria
| | - Hüseyin Demirbilek
- Department of Paediatric Endocrinology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Sara Al-Khawaga
- Division of Endocrinology, Department of Paediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Khalid Hussain
- Division of Endocrinology, Department of Paediatric Medicine, Sidra Medicine, Doha, Qatar
| |
Collapse
|
11
|
Lu B, Tonne JM, Munoz-Gomez M, Ikeda Y. Hyperinsulinemic hypoglycemia subtype glucokinase V91L mutant induces necrosis in β-cells via ATP depletion. Biochem Biophys Rep 2019; 17:108-113. [PMID: 30623114 PMCID: PMC6304456 DOI: 10.1016/j.bbrep.2018.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/09/2018] [Accepted: 12/06/2018] [Indexed: 12/24/2022] Open
Abstract
Hyperinsulinemic hypoglycemia subtype glucokinase (GCK-HH) is caused by an activating mutation in glucokinase (GCK) and has been shown to increase β-cell death. However, the mechanism of β-cell death in GCK-HH remains poorly understood. Here, we expressed the GCK-HH V91L GCK mutant in INS-1 832/13 cells to determine the effect of the mutation on β-cell viability and the mechanisms of β-cell death. We showed that expression of the V91L GCK mutant in INS-1 832/13 cells resulted in a rapid glucose concentration-dependent loss of cell viability. At 11 mM D-glucose, INS-1 832/13 cells expressing V91L GCK showed increased cell permeability without significant increases in Annexin V staining or caspase 3/7 activation, indicating that these cells are primarily undergoing cell death via necrosis. Over-expression of SV40 large T antigen, which inhibits the p53 pathway, did not affect the V91L GCK-induced cell death. We also found that non-phosphorylatable L-glucose did not induce rapid cell death. Of note, glucose phosphorylation coincided with a 90% loss of intracellular ATP content. Thus, our data suggest that the GCK V91L mutant induces rapid necrosis in INS-1 cells through accelerated glucose phosphorylation, ATP depletion, and increased cell permeability. V91L glucokinase mutant induces glucose-dependent death in rat INS-1 832/13 cells. Glucose induces necrosis in INS-1 832/13 cells expressing V91L glucokinase mutant. V91L glucokinase mutant depletes adenosine triphosphate in INS-1 832/13 cells.
Collapse
Affiliation(s)
- Brian Lu
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA.,Virology and Gene Therapy Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Jason M Tonne
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Yasuhiro Ikeda
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA.,Virology and Gene Therapy Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| |
Collapse
|
12
|
Abstract
Pancreatic β-cells are finely tuned to secrete insulin so that plasma glucose levels are maintained within a narrow physiological range (3.5-5.5 mmol/L). Hyperinsulinaemic hypoglycaemia (HH) is the inappropriate secretion of insulin in the presence of low plasma glucose levels and leads to severe and persistent hypoglycaemia in neonates and children. Mutations in 12 different key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, PGM1 and PMM2) that are involved in the regulation of insulin secretion from pancreatic β-cells have been described to be responsible for the underlying molecular mechanisms leading to congenital HH. In HH due to the inhibitory effect of insulin on lipolysis and ketogenesis there is suppressed ketone body formation in the presence of hypoglycaemia thus leading to increased risk of hypoglycaemic brain injury. Therefore, a prompt diagnosis and immediate management of HH is essential to avoid hypoglycaemic brain injury and long-term neurological complications in children. Advances in molecular genetics, imaging techniques (18F-DOPA positron emission tomography/computed tomography scanning), medical therapy and surgical advances (laparoscopic and open pancreatectomy) have changed the management and improved the outcome of patients with HH. This review article provides an overview to the background, clinical presentation, diagnosis, molecular genetics and therapy in children with different forms of HH.
Collapse
Affiliation(s)
- Hüseyin Demirbilek
- Hacettepe University Faculty of Medicine, Department of Paediatric Endocrinology, Ankara, Turkey
| | - Khalid Hussain
- Sidra Medical and Research Center, Clinic of Paediatric Medicine, Doha, Qatar
,* Address for Correspondence: Sidra Medical and Research Center, Clinic of Paediatric Medicine, Doha, Qatar Phone: +974-30322007 E-mail:
| |
Collapse
|
13
|
Demirbilek H, Rahman SA, Buyukyilmaz GG, Hussain K. Diagnosis and treatment of hyperinsulinaemic hypoglycaemia and its implications for paediatric endocrinology. INTERNATIONAL JOURNAL OF PEDIATRIC ENDOCRINOLOGY 2017; 2017:9. [PMID: 28855921 PMCID: PMC5575922 DOI: 10.1186/s13633-017-0048-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 08/15/2017] [Indexed: 12/14/2022]
Abstract
Glucose homeostasis requires appropriate and synchronous coordination of metabolic events and hormonal activities to keep plasma glucose concentrations in a narrow range of 3.5–5.5 mmol/L. Insulin, the only glucose lowering hormone secreted from pancreatic β-cells, plays the key role in glucose homeostasis. Insulin release from pancreatic β-cells is mainly regulated by intracellular ATP-generating metabolic pathways. Hyperinsulinaemic hypoglycaemia (HH), the most common cause of severe and persistent hypoglycaemia in neonates and children, is the inappropriate secretion of insulin which occurs despite low plasma glucose levels leading to severe and persistent hypoketotic hypoglycaemia. Mutations in 12 different key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, PGM1 and PMM2) constitute the underlying molecular mechanisms of congenital HH. Since insulin supressess ketogenesis, the alternative energy source to the brain, a prompt diagnosis and immediate management of HH is essential to avoid irreversible hypoglycaemic brain damage in children. Advances in molecular genetics, imaging methods (18F–DOPA PET-CT), medical therapy and surgical approach (laparoscopic and open pancreatectomy) have changed the management and improved the outcome of patients with HH. This up to date review article provides a background to the diagnosis, molecular genetics, recent advances and therapeutic options in the field of HH in children.
Collapse
Affiliation(s)
- Huseyin Demirbilek
- Department of Paediatric Endocrinology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Sofia A Rahman
- Great Ormond Street Institute of Child Health, Genetics and Genomic Medicine, University College London, 30 Guilford Street, London, WC1N 1EH UK
| | - Gonul Gulal Buyukyilmaz
- Department of Paediatric Endocrinology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Khalid Hussain
- Department of Paediatric Medicine Sidra Medical & Research Center, OPC, C6-337, PO Box 26999, Doha, Qatar
| |
Collapse
|
14
|
Martínez R, Gutierrez-Nogués Á, Fernández-Ramos C, Velayos T, Vela A, Navas MÁ, Castaño L. Heterogeneity in phenotype of hyperinsulinism caused by activating glucokinase mutations: a novel mutation and its functional characterization. Clin Endocrinol (Oxf) 2017; 86:778-783. [PMID: 28247534 DOI: 10.1111/cen.13318] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/12/2016] [Accepted: 02/23/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Mutations in the GCK gene lead to different forms of glucokinase (GCK)-disease, activating mutations cause hyperinsulinaemic hypoglycaemia while inactivating mutations cause monogenic diabetes. Hyperinsulinism (HI) is a heterogeneous condition with a significant genetic component. The major causes are channelopathies, the other forms are rare and being caused by mutations in genes such as GCK. OBJECTIVE To describe the clinical and genetic presentation of four families with activating GCK mutations, and to explore the pathogenicity of the novel mutation identified through functional studies. RESULTS Four cases of HI with mutations in GCK were identified. These include one novel mutation (p.Trp99Cys). Functional analysis of the purified mutant fusion protein glutathione-S-transferase (GST)-GCK-p.Trp99Cys demonstrated that p.Trp99Cys is an activating mutation as it induces a higher affinity for glucose and increases the relative activity index more than 11 times. Moreover, the thermal stability of the mutant protein was similar to that of its wild type. All patients were responsive to diazoxide treatment. One of the mutations arose de novo, and two were dominantly inherited, although only one of them from an HI affected parent. The age of presentation in our cases varied widely from the neonatal period to adulthood. CONCLUSION The clinical phenotype of the GCK activating mutation carriers was heterogeneous, the severity of symptoms and age at presentation varied markedly between affected individuals, even within the same family. The novel activating GCK mutation (p.Trp99Cys) has a strong activating effect in vitro although it has been identified in one case of a milder and late-onset form of HI.
Collapse
Affiliation(s)
- Rosa Martínez
- Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, CIBERER, Cruces University Hospital, Barakaldo, Spain
| | - Ángel Gutierrez-Nogués
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, CIBERDEM and Hospital Clínico San Carlos Health Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Concepción Fernández-Ramos
- Pediatric Endocrinology Section, BioCruces Health Research Institute, UPV/EHU, Basurto University Hospital, Bilbao, Spain
| | - Teresa Velayos
- Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, CIBERER, Cruces University Hospital, Barakaldo, Spain
| | - Amaia Vela
- Pediatric Endocrinology Section, BioCruces Health Research Institute, UPV/EHU, Cruces University Hospital, CIBERDEM, CIBERER, Barakaldo, Bizkaia, Spain
| | - María-Ángeles Navas
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, CIBERDEM and Hospital Clínico San Carlos Health Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Luis Castaño
- Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, CIBERER, Cruces University Hospital, Barakaldo, Spain
| |
Collapse
|
15
|
Ajala ON, Huffman DM, Ghobrial II. Glucokinase mutation-a rare cause of recurrent hypoglycemia in adults: a case report and literature review. J Community Hosp Intern Med Perspect 2016; 6:32983. [PMID: 27802864 PMCID: PMC5089152 DOI: 10.3402/jchimp.v6.32983] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/30/2016] [Indexed: 02/02/2023] Open
Abstract
Background Hypoglycemia occurs frequently in patients both in the inpatient and outpatient settings. While most hypoglycemia unrelated to diabetes treatment results from excessive endogenous insulin action, rare cases involve functional and congenital mutations in glycolytic enzymes of insulin regulation. Case A 21-year-old obese woman presented to the emergency department with complaints of repeated episodes of lethargy, syncope, dizziness, and sweating. She was referred from an outside facility on suspicion of insulinoma, with severe hypoglycemia unresponsive to repeated dextrose infusions. Her plasma glucose was 20 mg/dl at presentation, 44 mg/dl on arrival at our facility, and remained low in spite of multiple dextrose infusions. The patient had been treated for persistent hyperinsulinemic hypoglycemia of infancy at our neonatal facility and 4 years ago was diagnosed as having an activating glucokinase (GCK) mutation. She was then treated with octreotide and diazoxide with improvement in symptoms and blood glucose levels. Conclusion Improved diagnostication and management of uncommon genetic mutations as typified in this patient with an activating mutation of the GCK gene has expanded the spectrum of disease in adult medicine. This calls for improved patient information dissemination across different levels and aspects of the health care delivery system to ensure cost-effective and timely health care.
Collapse
Affiliation(s)
- Oluremi N Ajala
- Department of Internal Medicine, University of Pittsburgh Medical Center, McKeesport, PA, USA;
| | - David M Huffman
- Department of Internal Medicine, University of Tennessee College of Medicine, Chattanooga, TN, USA
| | - Ibrahim I Ghobrial
- Department of Internal Medicine, University of Pittsburgh Medical Center, McKeesport, PA, USA
| |
Collapse
|
16
|
Martínez R, Fernández-Ramos C, Vela A, Velayos T, Aguayo A, Urrutia I, Rica I, Castaño L. Clinical and genetic characterization of congenital hyperinsulinism in Spain. Eur J Endocrinol 2016; 174:717-26. [PMID: 27188453 DOI: 10.1530/eje-16-0027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/07/2016] [Indexed: 12/30/2022]
Abstract
CONTEXT Congenital hyperinsulinism (CHI) is a clinically and genetically heterogeneous disease characterized by severe hypoglycemia caused by inappropriate insulin secretion by pancreatic β-cells. OBJECTIVE To characterize clinically and genetically CHI patients in Spain. DESIGN AND METHODS We included 50 patients with CHI from Spain. Clinical information was provided by the referring clinicians. Mutational analysis was carried out for KCNJ11, ABCC8, and GCK genes. The GLUD1, HNF4A, HNF1A, UCP2, and HADH genes were sequenced depending on the clinical phenotype. RESULTS We identified the genetic etiology in 28 of the 50 CHI patients tested: 21 had a mutation in KATP channel genes (42%), three in GLUD1 (6%), and four in GCK (8%). Most mutations were found in ABCC8 (20/50). Half of these patients (10/20) were homozygous or compound heterozygous, with nine being unresponsive to diazoxide treatment. The other half had heterozygous mutations in ABCC8, six of them being unresponsive to diazoxide treatment and four being responsive to diazoxide treatment. We identified 22 different mutations in the KATP channel genes, of which ten were novel. Notably, patients with ABCC8 mutations were diagnosed earlier, with lower blood glucose levels and required higher doses of diazoxide than those without a genetic diagnosis. CONCLUSIONS Genetic analysis revealed mutations in 56% of the CHI patients. ABCC8 mutations are the most frequent cause of CHI in Spain. We found ten novel mutations in the KATP channel genes. The genetic diagnosis is more likely to be achieved in patients with onset within the first week of life and in those who fail to respond to diazoxide treatment.
Collapse
Affiliation(s)
- R Martínez
- Endocrinology and Diabetes Research GroupBioCruces Health Research Institute, Cruces University Hospital, CIBERDEM, CIBERER, UPV-EHU, Barakaldo, Spain
| | - C Fernández-Ramos
- Pediatric Endocrinology SectionBasurto University Hospital, BioCruces Health Research Institute, UPV/EHU, Bilbao, Spain
| | - A Vela
- Pediatric Endocrinology SectionCruces University Hospital, BioCruces Health Research Institute, CIBERDEM, CIBERER, UPV/EHU, Barakaldo, Spain
| | - T Velayos
- Endocrinology and Diabetes Research GroupBioCruces Health Research Institute, Cruces University Hospital, CIBERDEM, CIBERER, UPV-EHU, Barakaldo, Spain
| | - A Aguayo
- Endocrinology and Diabetes Research GroupBioCruces Health Research Institute, Cruces University Hospital, CIBERDEM, CIBERER, UPV-EHU, Barakaldo, Spain
| | - I Urrutia
- Endocrinology and Diabetes Research GroupBioCruces Health Research Institute, Cruces University Hospital, CIBERDEM, CIBERER, UPV-EHU, Barakaldo, Spain
| | - I Rica
- Pediatric Endocrinology SectionCruces University Hospital, BioCruces Health Research Institute, CIBERDEM, CIBERER, UPV/EHU, Barakaldo, Spain
| | - L Castaño
- Endocrinology and Diabetes Research GroupBioCruces Health Research Institute, Cruces University Hospital, CIBERDEM, CIBERER, UPV-EHU, Barakaldo, Spain
| |
Collapse
|
17
|
Abstract
The use of targeted gene panels now allows the analysis of all the genes known to cause a disease in a single test. For neonatal diabetes, this has resulted in a paradigm shift with patients receiving a genetic diagnosis early and the genetic results guiding their clinical management. Exome and genome sequencing are powerful tools to identify novel genetic causes of known diseases. For neonatal diabetes, the use of these technologies has resulted in the identification of 2 novel disease genes (GATA6 and STAT3) and a novel regulatory element of PTF1A, in which mutations cause pancreatic agenesis.
Collapse
|
18
|
Oriola J, Moreno F, Gutiérrez-Nogués A, León S, García-Herrero CM, Vincent O, Navas MA. Lack of glibenclamide response in a case of permanent neonatal diabetes caused by incomplete inactivation of glucokinase. JIMD Rep 2015; 20:21-6. [PMID: 25665835 DOI: 10.1007/8904_2014_383] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 10/24/2014] [Accepted: 11/10/2014] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Hypoglycaemic drugs that close the KATP channel have been tested in patients with permanent neonatal diabetes due to glucokinase mutations (PNDM-GCK). From the results obtained, it has been suggested that this treatment may be beneficial in patients carrying GCK mutations with mild kinetic defects. The aim of this study was to evaluate the kinetic analysis of glucokinase activity as a predictive factor for response to sulphonylureas in PNDM-GCK. METHODS The clinical characteristics of two siblings with PNDM born to non-consanguineous parents are described. Mutation analysis of KCNJ11, INS and GCK genes was done by sequencing. A comprehensive functional characterisation of GCK mutation was undertaken. Glibenclamide treatment was assayed for 16 weeks in one child. Response to treatment was evaluated by means of fasting glycaemia, C-peptide and HbA1c levels. RESULTS Compound heterozygous GCK mutations (p.Ile19Asn and p.Ser441Trp) were identified. Functional analysis of GCK(p.Ile19Asn) indicated that this mutant retained more than 70% of wild-type catalytic activity in vitro, with a slight increase of thermolability. This mutation did not impair the interaction with the glucokinase regulatory protein, and the enzymatic activity of the GCK(p.Ile19Asn) mutant is restored to wild-type levels in the presence of GCK allosteric activator LY2121260. However, glibenclamide treatment of the patient on a reduced dose of insulin did not reduce HbA1c levels, and C-peptide increased only very slightly. CONCLUSION Hypoglycaemic drugs acting on the KATP channel might not be useful in the treatment of PNDM-GCK, even in patients carrying GCK mutations with mild kinetic defects.
Collapse
Affiliation(s)
- Josep Oriola
- Servicio de Bioquímica y Genética Molecular. Hospital Clínic. Departamento de Ciencias Fisiológicas I. Facultad de Medicina., Universidad de Barcelona, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
19
|
Yorifuji T. Congenital hyperinsulinism: current status and future perspectives. Ann Pediatr Endocrinol Metab 2014; 19:57-68. [PMID: 25077087 PMCID: PMC4114053 DOI: 10.6065/apem.2014.19.2.57] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 04/14/2014] [Indexed: 11/25/2022] Open
Abstract
The diagnosis and treatment of congenital hyperinsulinism (CHI) have made a remarkable progress over the past 20 years and, currently, it is relatively rare to see patients who are left with severe psychomotor delay. The improvement was made possible by the recent developments in the understanding of the molecular and pathological basis of CHI. Known etiologies include inactivating mutations of the KATP channel genes (ABCC8 and KCNJ11) and HNF4A, HNF1A, HADH, and UCP2 or activating mutations of GLUD1, GCK, and SLC16A1. The understanding of the focal form of KATP channel CHI and its detection by (18)F-fluoro-L-DOPA positron emission tomography have revolutionized the management of CHI, and many patients can be cured without postoperative diabetes mellitus. The incidence of the focal form appears to be higher in Asian countries; therefore, the establishment of treatment systems is even more important in this population. In addition to diazoxide or long-term subcutaneous infusion of octreotide or glucagon, long-acting octreotide or lanreotide have also been used successfully until spontaneous remission. Because of these medications, near-total pancreatectomy is less often performed even for the diazoxide-unresponsive diffuse form of CHI. Other promising medications include pasireotide, small-molecule correctors such as sulfonylurea or carbamazepine, GLP1 receptor antagonists, or mammalian target of rapamycin inhibitors. Unsolved questions in this field include the identification of the remaining genes responsible for CHI, the mechanisms leading to transient CHI, and the mechanisms responsible for the spontaneous remission of CHI. This article reviews recent developments and hypothesis regarding these questions.
Collapse
Affiliation(s)
- Tohru Yorifuji
- Department of Pediatric Endocrinology and Metabolism, Children's Medical Center, Osaka City General Hospital, Osaka, Japan
| |
Collapse
|
20
|
Szlyk B, Braun CR, Ljubicic S, Patton E, Bird GH, Osundiji MA, Matschinsky FM, Walensky LD, Danial NN. A phospho-BAD BH3 helix activates glucokinase by a mechanism distinct from that of allosteric activators. Nat Struct Mol Biol 2013; 21:36-42. [PMID: 24317490 DOI: 10.1038/nsmb.2717] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 10/15/2013] [Indexed: 01/10/2023]
Abstract
Glucokinase (GK) is a glucose-phosphorylating enzyme that regulates insulin release and hepatic metabolism, and its loss of function is implicated in diabetes pathogenesis. GK activators (GKAs) are attractive therapeutics in diabetes; however, clinical data indicate that their benefits can be offset by hypoglycemia, owing to marked allosteric enhancement of the enzyme's glucose affinity. We show that a phosphomimetic of the BCL-2 homology 3 (BH3) α-helix derived from human BAD, a GK-binding partner, increases the enzyme catalytic rate without dramatically changing glucose affinity, thus providing a new mechanism for pharmacologic activation of GK. Remarkably, BAD BH3 phosphomimetic mediates these effects by engaging a new region near the enzyme's active site. This interaction increases insulin secretion in human islets and restores the function of naturally occurring human GK mutants at the active site. Thus, BAD phosphomimetics may serve as a new class of GKAs.
Collapse
Affiliation(s)
- Benjamin Szlyk
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2]
| | - Craig R Braun
- 1] Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2]
| | - Sanda Ljubicic
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2] Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| | - Elaura Patton
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Gregory H Bird
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Mayowa A Osundiji
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA
| | - Franz M Matschinsky
- Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Loren D Walensky
- 1] Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2] Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA. [3] Department of Pediatric Oncology, Children's Hospital, Boston, Massachusetts, USA
| | - Nika N Danial
- 1] Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA. [2] Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
21
|
Schermerhorn T. Normal glucose metabolism in carnivores overlaps with diabetes pathology in non-carnivores. Front Endocrinol (Lausanne) 2013; 4:188. [PMID: 24348462 PMCID: PMC3847661 DOI: 10.3389/fendo.2013.00188] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/19/2013] [Indexed: 12/15/2022] Open
Abstract
Carnivores, such as the dolphin and the domestic cat, have numerous adaptations that befit consumption of diets with high protein and fat content, with little carbohydrate content. Consequently, nutrient metabolism in carnivorous species differs substantially from that of non-carnivores. Important metabolic pathways known to differ between carnivores and non-carnivores are implicated in the development of diabetes and insulin resistance in non-carnivores: (1) the hepatic glucokinase (GCK) pathway is absent in healthy carnivores yet GCK deficiency may result in diabetes in rodents and humans, (2) healthy dolphins and cats are prone to periods of fasting hyperglycemia and exhibit insulin resistance, both of which are risk factors for diabetes in non-carnivores. Similarly, carnivores develop naturally occurring diseases such as hemochromatosis, fatty liver, obesity, and diabetes that have strong parallels with the same disorders in humans. Understanding how evolution, environment, diet, and domestication may play a role with nutrient metabolism in the dolphin and cat may also be relevant to human diabetes.
Collapse
Affiliation(s)
- Thomas Schermerhorn
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
- *Correspondence: Thomas Schermerhorn, Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506-5606, USA e-mail:
| |
Collapse
|
22
|
Shammas C, Neocleous V, Phelan MM, Lian LY, Skordis N, Phylactou LA. A report of 2 new cases of MODY2 and review of the literature: implications in the search for type 2 diabetes drugs. Metabolism 2013; 62:1535-42. [PMID: 23890519 DOI: 10.1016/j.metabol.2013.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/11/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
Glucokinase (GCK) acts as a glucose sensor and stimulates the release of insulin from pancreatic β-cells and any GCK gene mutations can lead to different forms of diabetes, such as GCK-monogenic diabetes of the young type 2 (MODY2), permanent neonatal diabetes and congenital hyperinsulinism. Many MODY2 causing mutations display a variation in the degree of severity, ranging from mild dietary-restricted forms to more detrimental presentation requiring insulin replacement. The present study reviews known and two novel GCK mutations in terms of molecular perturbation of the GCK atomic structure but also emphasizes the inactivating and activating properties of the GCK as treatment for T2DM. In silico analysis demonstrated that the newly discovered mutation p.Arg447Pro causes structural conformational changes that lead to the destabilization of the functional properties of the protein resulting in the reduction of glucose and MgATP2- affinity. The novel p.Glu440Stop nonsense mutation on the other hand inactivates the cytoplasmic enzymatic activity of the protein as it is responsible for the loss of the C-terminal end of the polypeptide that includes vital glucose-releasing residues. Based on the in silico models of existing structural data we identified several classes of GCK mutations and discuss their relation to disease outcome. GCK has a central role in controlling body glucose homeostasis and therefore is considered an outstanding drug target for developing new antidiabetic therapies using small molecular activators (GKAs). This study emphasizes the importance in understanding how inactivating and activating GCK mutations affect the mechanistic properties of this glucose sensor. Such information can become the basis for drug discovery of therapeutic compounds and the treatment of T2DM by targeting the GCK allosteric activator site.
Collapse
Affiliation(s)
- Christos Shammas
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | | | | | | | | | | |
Collapse
|
23
|
Domínguez-Bendala J, Inverardi L, Ricordi C. Regeneration of pancreatic beta-cell mass for the treatment of diabetes. Expert Opin Biol Ther 2012; 12:731-41. [DOI: 10.1517/14712598.2012.679654] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
24
|
Quan Y, Barszczyk A, Feng ZP, Sun HS. Current understanding of K ATP channels in neonatal diseases: focus on insulin secretion disorders. Acta Pharmacol Sin 2011; 32:765-80. [PMID: 21602835 PMCID: PMC4009965 DOI: 10.1038/aps.2011.57] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/13/2011] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are cell metabolic sensors that couple cell metabolic status to electric activity, thus regulating many cellular functions. In pancreatic beta cells, K(ATP) channels modulate insulin secretion in response to fluctuations in plasma glucose level, and play an important role in glucose homeostasis. Recent studies show that gain-of-function and loss-of-function mutations in K(ATP) channel subunits cause neonatal diabetes mellitus and congenital hyperinsulinism respectively. These findings lead to significant changes in the diagnosis and treatment for neonatal insulin secretion disorders. This review describes the physiological and pathophysiological functions of K(ATP) channels in glucose homeostasis, their specific roles in neonatal diabetes mellitus and congenital hyperinsulinism, as well as future perspectives of K(ATP) channels in neonatal diseases.
Collapse
Affiliation(s)
- Yi Quan
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Andrew Barszczyk
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Zhong-ping Feng
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Hong-shuo Sun
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Surgery, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Pharmacology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| |
Collapse
|
25
|
Beer NL, van de Bunt M, Colclough K, Lukacs C, Arundel P, Chik CL, Grimsby J, Ellard S, Gloyn AL. Discovery of a novel site regulating glucokinase activity following characterization of a new mutation causing hyperinsulinemic hypoglycemia in humans. J Biol Chem 2011; 286:19118-26. [PMID: 21454522 DOI: 10.1074/jbc.m111.223362] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Type 2 diabetes is a global problem, and current ineffective therapeutic strategies pave the way for novel treatments like small molecular activators targeting glucokinase (GCK). GCK activity is fundamental to beta cell and hepatocyte glucose metabolism, and heterozygous activating and inactivating GCK mutations cause hyperinsulinemic hypoglycemia (HH) and maturity onset diabetes of the young (MODY) respectively. Over 600 naturally occurring inactivating mutations have been reported, whereas only 13 activating mutations are documented to date. We report two novel GCK HH mutations (V389L and T103S) at residues where MODY mutations also occur (V389D and T103I). Using recombinant proteins with in vitro assays, we demonstrated that both HH mutants had a greater relative activity index than wild type (6.0 for V389L, 8.4 for T103S, and 1.0 for wild type). This was driven by an increased affinity for glucose (S(0.5), 3.3 ± 0.1 and 3.5 ± 0.1 mm, respectively) versus wild type (7.5 ± 0.1 mm). Correspondingly, the V389D and T103I MODY mutants had markedly reduced relative activity indexes (<0.1). T103I had an altered affinity for glucose (S(0.5), 24.9 ± 0.6 mm), whereas V389D also exhibited a reduced affinity for ATP and decreased catalysis rate (S(0.5), 78.6 ± 4.5 mm; ATP(K(m)), 1.5 ± 0.1 mm; K(cat), 10.3 ± 1.1s(-1)) compared with wild type (ATP(K(m)), 0.4 ± <0.1; K(cat), 62.9 ± 1.2). Both Thr-103 mutants showed reduced inhibition by the endogenous hepatic inhibitor glucokinase regulatory protein. Molecular modeling demonstrated that Thr-103 maps to the allosteric activator site, whereas Val-389 is located remotely to this position and all other previously reported activating mutations, highlighting α-helix 11 as a novel region regulating GCK activity. Our data suggest that pharmacological manipulation of GCK activity at locations distal from the allosteric activator site is possible.
Collapse
Affiliation(s)
- Nicola L Beer
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford OX3 7LJ, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Marquard J, Palladino AA, Stanley CA, Mayatepek E, Meissner T. Rare forms of congenital hyperinsulinism. Semin Pediatr Surg 2011; 20:38-44. [PMID: 21186003 DOI: 10.1053/j.sempedsurg.2010.10.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rare forms of congenital hyperinsulinism (CHI) are caused by mutations in GLUD1 (encoding glutamate dehydrogenase), GCK (encoding glucokinase), HADH (encoding for L-3-hydroxyacyl-CoA dehydrogenase), SLC16A1 (encoding the monocarboxylat transporter 1), HNF4A (encoding hepatocyte nuclear factor 4α) or UCP2 (encoding mitochondrial uncoupling protein 2). The clinical presentation is very heterogeneous in regards to age of onset, severity, and manner of symptoms, as well as the response to medical treatment. Special individual characteristics have to be accounted in diagnosis and treatment. Diazoxide is the first-line drug for the rare forms of CHI for long-term treatment but is not entirely effective in some of these rarer defects (GCK, MCT1). The use of diazoxide is often limited by side effects and the use of octreotide as second-line drug has to be considered. A near-total pancreatectomy is only reserved for patients with diffuse disease and resistance to medical treatment as a last resort. Patients with CHI should be managed by centers with a highly experienced team in diagnostic work-up and treatment of this disease.
Collapse
Affiliation(s)
- Jan Marquard
- Department of General Pediatrics, University Children's Hospital Düsseldorf, Germany.
| | | | | | | | | |
Collapse
|
27
|
Hussain K. Mutations in pancreatic ß-cell Glucokinase as a cause of hyperinsulinaemic hypoglycaemia and neonatal diabetes mellitus. Rev Endocr Metab Disord 2010; 11:179-83. [PMID: 20878480 DOI: 10.1007/s11154-010-9147-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Glucokinase is a key enzyme involved in regulating insulin secretion from the pancreatic ß-cell. The unique role of glucokinase in human glucose physiology is illustrated by the fact that genetic mutations in glucokinase can either cause hyperglycaemia or hypoglycaemia. Heterozygous inactivating mutations in glucokinase cause maturity-onset diabetes of the young (MODY), homozygous inactivating in glucokinase mutations result in permanent neonatal diabetes whereas heterozygous activating glucokinase mutations cause hyperinsulinaemic hypoglycaemia.
Collapse
Affiliation(s)
- Khalid Hussain
- Clinical and Molecular Genetics Unit, The Developmental Endocrinology Research Group, Institute of Child Health, Hospital for Children NHS Trust, University College London, Great Ormond Street, London, UK.
| |
Collapse
|