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Neonatal Diabetes Mellitus. MEDICAL BULLETIN OF SISLI ETFAL HOSPITAL 2018; 52:71-78. [PMID: 32595377 PMCID: PMC7315067 DOI: 10.14744/semb.2017.51422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 06/07/2017] [Indexed: 11/23/2022]
Abstract
Neonatal diabetes is a rare cause of hyperglycemia in the neonatal period. It is caused by mutations in genes that encode proteins playing critical roles in normal functions of pancreatic beta cells. Neonatal diabetes is divided into temporary and permanent subtypes. Treatment is based on the correction of fluid-electrolyte disturbances and hyperglycemia. Patients respond to insulin or sulfonylurea treatment according to the mutation type. Close glucose monitoring and education of caregivers about diabetes are vital.
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Prioritization of Variants Detected by Next Generation Sequencing According to the Mutation Tolerance and Mutational Architecture of the Corresponding Genes. Int J Mol Sci 2018; 19:ijms19061584. [PMID: 29861492 PMCID: PMC6032105 DOI: 10.3390/ijms19061584] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/09/2018] [Accepted: 05/23/2018] [Indexed: 12/27/2022] Open
Abstract
The biggest challenge geneticists face when applying next-generation sequencing technology to the diagnosis of rare diseases is determining which rare variants, from the dozens or hundreds detected, are potentially implicated in the patient’s phenotype. Thus, variant prioritization is an essential step in the process of rare disease diagnosis. In addition to conducting the usual in-silico analyses to predict variant pathogenicity (based on nucleotide/amino-acid conservation and the differences between the physicochemical features of the amino-acid change), three important concepts should be borne in mind. The first is the “mutation tolerance” of the genes in which variants are located. This describes the susceptibility of a given gene to any functional mutation and depends on the strength of purifying selection acting against it. The second is the “mutational architecture” of each gene. This describes the type and location of mutations previously identified in the gene, and their association with different phenotypes or degrees of severity. The third is the mode of inheritance (inherited vs. de novo) of the variants detected. Here, we discuss the importance of each of these concepts for variant prioritization in the diagnosis of rare diseases. Using real data, we show how genes, rather than variants, can be prioritized by calculating a gene-specific mutation tolerance score. We also illustrate the influence of mutational architecture on variant prioritization using five paradigmatic examples. Finally, we discuss the importance of familial variant analysis as final step in variant prioritization.
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Firdous P, Nissar K, Ali S, Ganai BA, Shabir U, Hassan T, Masoodi SR. Genetic Testing of Maturity-Onset Diabetes of the Young Current Status and Future Perspectives. Front Endocrinol (Lausanne) 2018; 9:253. [PMID: 29867778 PMCID: PMC5966560 DOI: 10.3389/fendo.2018.00253] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 05/02/2018] [Indexed: 12/12/2022] Open
Abstract
Diabetes is a global epidemic problem growing exponentially in Asian countries posing a serious threat. Among diabetes, maturity-onset diabetes of the young (MODY) is a heterogeneous group of monogenic disorders that occurs due to β cell dysfunction. Genetic defects in the pancreatic β-cells result in the decrease of insulin production required for glucose utilization thereby lead to early-onset diabetes (often <25 years). It is generally considered as non-insulin dependent form of diabetes and comprises of 1-5% of total diabetes. Till date, 14 genes have been identified and mutation in them may lead to MODY. Different genetic testing methodologies like linkage analysis, restriction fragment length polymorphism, and DNA sequencing are used for the accurate and correct investigation of gene mutations associated with MODY. The next-generation sequencing has emerged as one of the most promising and effective tools to identify novel mutated genes related to MODY. Diagnosis of MODY is mainly relying on the sequential screening of the three marker genes like hepatocyte nuclear factor 1 alpha (HNF1α), hepatocyte nuclear factor 4 alpha (HNF4α), and glucokinase (GCK). Interestingly, MODY patients can be managed by diet alone for many years and may also require minimal doses of sulfonylureas. The primary objective of this article is to provide a review on current status of MODY, its prevalence, genetic testing/diagnosis, possible treatment, and future perspective.
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Affiliation(s)
- Parveena Firdous
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Kamran Nissar
- Department of Biochemistry, University of Kashmir, Srinagar, India
| | - Sajad Ali
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Bashir Ahmad Ganai
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
- *Correspondence: Bashir Ahmad Ganai,
| | - Uzma Shabir
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Toyeeba Hassan
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Shariq Rashid Masoodi
- Department of Endocrinology, Sher-I-Kashmir Institute of Medical Sciences, Srinagar, India
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54
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Effect of gene-lifestyle interaction on gestational diabetes risk. Oncotarget 2017; 8:112024-112035. [PMID: 29340108 PMCID: PMC5762376 DOI: 10.18632/oncotarget.22999] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/27/2017] [Indexed: 11/29/2022] Open
Abstract
We hypothesized that the association of certain lifestyle parameters with gestational diabetes mellitus (GDM) risk would depend on susceptibility loci. In total, 278 Russian women with GDM and 179 controls completed questionnaires about lifestyle habits (food consumption, physical activity and smoking). GDM was diagnosed according to the criteria of the International Association of Diabetes and Pregnancy Study Groups. Maternal blood was sampled for genotyping single-nucleotide polymorphisms (SNPs) in MTNR1B (rs10830963 and rs1387153), GCK (rs1799884), KCNJ11 (rs5219), IGF2BP2 (rs4402960), TCF7L2 (rs7903146 and rs12255372), CDKAL1 (rs7754840), IRS1 (rs1801278) and FTO (rs9939609). Binary logistic regression revealed an interaction effect of sausage intake and the number of risk alleles of two SNPs (rs10830963 in MTNR1B and rs1799884 in GCK) on GDM risk (P < 0.001). Among women without risk alleles of these two SNPs, sausage consumption was positively associated with GDM risk (P trend = 0.045). This difference was not revealed in women carrying 1 or more risk alleles. The risk of GDM increased as the number of risk alles increased in participants with low and moderate sausage consumption (P trend <0.001 and 0.006, respectively), while the risk of GDM in women with high sausage consumption remained relatively high, independent of the number of risk alleles. These findings indicate that the association of sausage consumption with GDM risk can be determined based on the number of risk alleles of rs10830963 in MTNR1B and rs1799884 in GCK.
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55
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Lu M, Li C. Nutrient sensing in pancreatic islets: lessons from congenital hyperinsulinism and monogenic diabetes. Ann N Y Acad Sci 2017; 1411:65-82. [PMID: 29044608 DOI: 10.1111/nyas.13448] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/05/2017] [Accepted: 07/14/2017] [Indexed: 12/14/2022]
Abstract
Pancreatic beta cells sense changes in nutrients during the cycles of fasting and feeding and release insulin accordingly to maintain glucose homeostasis. Abnormal beta cell nutrient sensing resulting from gene mutations leads to hypoglycemia or diabetes. Glucokinase (GCK) plays a key role in beta cell glucose sensing. As one form of congenital hyperinsulinism (CHI), activating mutations of GCK result in a decreased threshold for glucose-stimulated insulin secretion and hypoglycemia. In contrast, inactivating mutations of GCK result in diabetes, including a mild form (MODY2) and a severe form (permanent neonatal diabetes mellitus (PNDM)). Mutations of beta cell ion channels involved in insulin secretion regulation also alter glucose sensing. Activating or inactivating mutations of ATP-dependent potassium (KATP ) channel genes result in severe but completely opposite clinical phenotypes, including PNDM and CHI. Mutations of the other ion channels, including voltage-gated potassium channels (Kv 7.1) and voltage-gated calcium channels, also lead to abnormal glucose sensing and CHI. Furthermore, amino acids can stimulate insulin secretion in a glucose-independent manner in some forms of CHI, including activating mutations of the glutamate dehydrogenase gene, HDAH deficiency, and inactivating mutations of KATP channel genes. These genetic defects have provided insight into a better understanding of the complicated nature of beta cell fuel-sensing mechanisms.
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Affiliation(s)
- Ming Lu
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics & Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, China
| | - Changhong Li
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics & Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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56
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Johansson BB, Fjeld K, Solheim MH, Shirakawa J, Zhang E, Keindl M, Hu J, Lindqvist A, Døskeland A, Mellgren G, Flatmark T, Njølstad PR, Kulkarni RN, Wierup N, Aukrust I, Bjørkhaug L. Nuclear import of glucokinase in pancreatic beta-cells is mediated by a nuclear localization signal and modulated by SUMOylation. Mol Cell Endocrinol 2017. [PMID: 28648619 DOI: 10.1016/j.mce.2017.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The localization of glucokinase in pancreatic beta-cell nuclei is a controversial issue. Although previous reports suggest such a localization, the mechanism for its import has so far not been identified. Using immunofluorescence, subcellular fractionation and mass spectrometry, we present evidence in support of glucokinase localization in beta-cell nuclei of human and mouse pancreatic sections, as well as in human and mouse isolated islets, and murine MIN6 cells. We have identified a conserved, seven-residue nuclear localization signal (30LKKVMRR36) in the human enzyme. Substituting the residues KK31,32 and RR35,36 with AA led to a loss of its nuclear localization in transfected cells. Furthermore, our data indicates that SUMOylation of glucokinase modulates its nuclear import, while high glucose concentrations do not significantly alter the enzyme nuclear/cytosolic ratio. Thus, for the first time, we provide data in support of a nuclear import of glucokinase mediated by a redundant mechanism, involving a nuclear localization signal, and which is modulated by its SUMOylation. These findings add new knowledge to the functional role of glucokinase in the pancreatic beta-cell.
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Affiliation(s)
- Bente Berg Johansson
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Karianne Fjeld
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Marie Holm Solheim
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Harvard Medical School, Boston, MA, USA
| | - Jun Shirakawa
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School and Harvard Stem Cell Institute, Boston, MA, USA; Department of Endocrinology and Metabolism, Yokohama City University, Yokohama, Japan
| | | | - Magdalena Keindl
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Jiang Hu
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School and Harvard Stem Cell Institute, Boston, MA, USA
| | | | - Anne Døskeland
- Proteomics Unit (PROBE), Department of Biomedicine, University of Bergen, Norway
| | - Gunnar Mellgren
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway; Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Pål Rasmus Njølstad
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Rohit N Kulkarni
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School and Harvard Stem Cell Institute, Boston, MA, USA
| | - Nils Wierup
- Lund University Diabetes Centre, Malmö, Sweden
| | - Ingvild Aukrust
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Lise Bjørkhaug
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; Department of Biomedical Laboratory Sciences and Chemical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
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57
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Aloi C, Salina A, Minuto N, Tallone R, Lugani F, Mascagni A, Mazza O, Cassanello M, Maghnie M, d'Annunzio G. Glucokinase mutations in pediatric patients with impaired fasting glucose. Acta Diabetol 2017; 54:913-923. [PMID: 28726111 DOI: 10.1007/s00592-017-1021-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/14/2017] [Indexed: 10/19/2022]
Abstract
AIMS Our aim was to detect the frequency of glucokinase (GCK) gene mutations in a cohort of patients with impaired fasting glucose and to describe the clinical manifestations of identified variants. We also aimed at predicting the effect of the novel missense mutations by computational approach. METHODS Overall 100 unrelated Italian families with impaired fasting glucose were enrolled and subdivided into two cohorts according to strict and to mild criteria for diagnosis of maturity-onset diabetes of the young (MODY). GCK gene sequencing was performed in all participants. RESULTS Fifty-three Italian families with 44 different mutations affecting the GCK and co-segregating with the clinical phenotype of GCK/MODY were identified. All mutations were in heterozygous state. In Sample 1, GCK defects were found in 32/36 (88.9%) subjects selected with strict MODY diagnostic criteria, while in Sample 2 GCK defects were found in 21/64 (32.8%) subjects selected with mild MODY diagnostic criteria. CONCLUSIONS Our study enlarged the wide spectrum of GCK defects by adding 9 novel variants. The application of strict recruitment criteria resulted in 88.9% incidence of GCK/MODY, which confirmed it as the commonest form of MODY in the Italian population. In order to avoid misdiagnosis of GCK/MODY, it could be useful to perform molecular screening even if one or more clinical parameters for the diagnosis of MODY are missing. Computational analysis is useful to understand the effect of GCK defect on protein functionality, especially when the novel identified variant is a missense mutation and/or parents' DNA is not available.
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Affiliation(s)
- C Aloi
- Laboratory of Diabetology - Laboratory for the Study of Inborn Errors of Metabolism, Istituto Giannina Gaslini, Genoa, Italy
| | - A Salina
- Laboratory of Diabetology - Laboratory for the Study of Inborn Errors of Metabolism, Istituto Giannina Gaslini, Genoa, Italy
| | - N Minuto
- Pediatric Clinic, Regional Center of Diabetes, Istituto Giannina Gaslini, Via G. Gaslini, 5, 16147, Genoa, Italy
| | - R Tallone
- Pediatric Clinic, Regional Center of Diabetes, Istituto Giannina Gaslini, Via G. Gaslini, 5, 16147, Genoa, Italy
| | - F Lugani
- Laboratory of Pathophysiology of Uremia, Istituto Giannina Gaslini, Genoa, Italy
| | - A Mascagni
- Laboratory for the Study of Inborn Errors of Metabolism, DINOGMI, University of Genoa, Genoa, Italy
| | - O Mazza
- Laboratory for the Study of Inborn Errors of Metabolism, Istituto Giannina Gaslini, Genoa, Italy
| | - M Cassanello
- Laboratory for the Study of Inborn Errors of Metabolism, Istituto Giannina Gaslini, Genoa, Italy
| | - M Maghnie
- Pediatric Clinic, University of Genoa, Genoa, Italy
| | - G d'Annunzio
- Pediatric Clinic, Regional Center of Diabetes, Istituto Giannina Gaslini, Via G. Gaslini, 5, 16147, Genoa, Italy.
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58
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Okuyama T, Shirakawa J, Yanagisawa H, Kyohara M, Yamazaki S, Tajima K, Togashi Y, Terauchi Y. Identification of the matricellular protein Fibulin-5 as a target molecule of glucokinase-mediated calcineurin/NFAT signaling in pancreatic islets. Sci Rep 2017; 7:2364. [PMID: 28539593 PMCID: PMC5443834 DOI: 10.1038/s41598-017-02535-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 04/12/2017] [Indexed: 12/12/2022] Open
Abstract
Glucokinase-mediated glucose signaling induces insulin secretion, proliferation, and apoptosis in pancreatic β-cells. However, the precise molecular mechanisms underlying these processes are not clearly understood. Here, we demonstrated that glucokinase activation using a glucokinase activator (GKA) significantly upregulated the expression of Fibulin-5 (Fbln5), a matricellular protein involved in matrix-cell signaling, in isolated mouse islets. The islet Fbln5 expression was induced by ambient glucose in a time- and dose-dependent manner and further enhanced by high-fat diet or the deletion of insulin receptor substrate 2 (IRS-2), whereas the GKA-induced increase in Fbln5 expression was diminished in Irs-2-deficient islets. GKA-induced Fbln5 upregulation in the islets was blunted by a glucokinase inhibitor, KATP channel opener, Ca2+ channel blocker and calcineurin inhibitor, while it was augmented by harmine, a dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) 1 A inhibitor. Although deletion of Fbln5 in mice had no significant effects on the glucose tolerance or β-cell functions, adenovirus-mediated Fbln5 overexpression increased glucose-stimulated insulin secretion in INS-1 rat insulinoma cells. Since the islet Fbln5 expression is regulated through a glucokinase/KATP channel/calcineurin/nuclear factor of activated T cells (NFAT) pathway crucial for the maintenance of β-cell functions, further investigation of Fbln5 functions in the islets is warranted.
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Affiliation(s)
- Tomoko Okuyama
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan
| | - Jun Shirakawa
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan.
| | - Hiromi Yanagisawa
- Life Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Japan
| | - Mayu Kyohara
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan
| | - Shunsuke Yamazaki
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan
| | - Kazuki Tajima
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan
| | - Yu Togashi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama, Japan.
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59
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Johansson BB, Irgens HU, Molnes J, Sztromwasser P, Aukrust I, Juliusson PB, Søvik O, Levy S, Skrivarhaug T, Joner G, Molven A, Johansson S, Njølstad PR. Targeted next-generation sequencing reveals MODY in up to 6.5% of antibody-negative diabetes cases listed in the Norwegian Childhood Diabetes Registry. Diabetologia 2017; 60:625-635. [PMID: 27913849 DOI: 10.1007/s00125-016-4167-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 11/09/2016] [Indexed: 12/18/2022]
Abstract
AIMS/HYPOTHESIS MODY can be wrongly diagnosed as type 1 diabetes in children. We aimed to find the prevalence of MODY in a nationwide population-based registry of childhood diabetes. METHODS Using next-generation sequencing, we screened the HNF1A, HNF4A, HNF1B, GCK and INS genes in all 469 children (12.1%) negative for both GAD and IA-2 autoantibodies and 469 antibody-positive matched controls selected from the Norwegian Childhood Diabetes Registry (3882 children). Variants were classified using clinical diagnostic criteria for pathogenicity ranging from class 1 (neutral) to class 5 (pathogenic). RESULTS We identified 58 rare exonic and splice variants in cases and controls. Among antibody-negative patients, 6.5% had genetic variants of classes 3-5 (vs 2.4% in controls; p = 0.002). For the stricter classification (classes 4 and 5), the corresponding number was 4.1% (vs 0.2% in controls; p = 1.6 × 10-5). HNF1A showed the strongest enrichment of class 3-5 variants, with 3.9% among antibody-negative patients (vs 0.4% in controls; p = 0.0002). Antibody-negative carriers of variants in class 3 had a similar phenotype to those carrying variants in classes 4 and 5. CONCLUSIONS/INTERPRETATION This is the first study screening for MODY in all antibody-negative children in a nationwide population-based registry. Our results suggest that the prevalence of MODY in antibody-negative childhood diabetes may reach 6.5%. One-third of these MODY cases had not been recognised by clinicians. Since a precise diagnosis is important for treatment and genetic counselling, molecular screening of all antibody-negative children should be considered in routine diagnostics.
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Affiliation(s)
- Bente B Johansson
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Henrik U Irgens
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Department of Paediatrics, Haukeland University Hospital, Bergen, Norway
| | - Janne Molnes
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Paweł Sztromwasser
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ingvild Aukrust
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Petur B Juliusson
- Department of Paediatrics, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Oddmund Søvik
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Department of Paediatrics, Haukeland University Hospital, Bergen, Norway
| | - Shawn Levy
- Hudson Alpha Institute for Biotechnology, Huntsville, AL, USA
| | - Torild Skrivarhaug
- Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
| | - Geir Joner
- Division of Paediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Health and Society, University of Oslo, Oslo, Norway
| | - Anders Molven
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Gade Laboratory for Pathology, Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Stefan Johansson
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Pål R Njølstad
- K. G. Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, N-5020, Bergen, Norway.
- Department of Paediatrics, Haukeland University Hospital, Bergen, Norway.
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60
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Ofori JK, Salunkhe VA, Bagge A, Vishnu N, Nagao M, Mulder H, Wollheim CB, Eliasson L, Esguerra JLS. Elevated miR-130a/miR130b/miR-152 expression reduces intracellular ATP levels in the pancreatic beta cell. Sci Rep 2017; 7:44986. [PMID: 28332581 PMCID: PMC5362944 DOI: 10.1038/srep44986] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/17/2017] [Indexed: 12/16/2022] Open
Abstract
MicroRNAs have emerged as important players of gene regulation with significant impact in diverse disease processes. In type-2 diabetes, in which impaired insulin secretion is a major factor in disease progression, dysregulated microRNA expression in the insulin-secreting pancreatic beta cell has been widely-implicated. Here, we show that miR-130a-3p, miR-130b-3p, and miR-152-3p levels are elevated in the pancreatic islets of hyperglycaemic donors, corroborating previous findings about their upregulation in the islets of type-2 diabetes model Goto-Kakizaki rats. We demonstrated negative regulatory effects of the three microRNAs on pyruvate dehydrogenase E1 alpha (PDHA1) and on glucokinase (GCK) proteins, which are both involved in ATP production. Consequently, we found both proteins to be downregulated in the Goto-Kakizaki rat islets, while GCK mRNA expression showed reduced trend in the islets of type-2 diabetes donors. Overexpression of any of the three microRNAs in the insulin-secreting INS-1 832/13 cell line resulted in altered dynamics of intracellular ATP/ADP ratio ultimately perturbing fundamental ATP-requiring beta cell processes such as glucose-stimulated insulin secretion, insulin biosynthesis and processing. The data further strengthen the wide-ranging influence of microRNAs in pancreatic beta cell function, and hence their potential as therapeutic targets in type-2 diabetes.
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Affiliation(s)
- Jones K Ofori
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Vishal A Salunkhe
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Annika Bagge
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Molecular Metabolism, Department of Clinical Sciences-Malmö, Lund University, Malmö, 20502, Sweden
| | - Neelanjan Vishnu
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Molecular Metabolism, Department of Clinical Sciences-Malmö, Lund University, Malmö, 20502, Sweden
| | - Mototsugu Nagao
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Hindrik Mulder
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Molecular Metabolism, Department of Clinical Sciences-Malmö, Lund University, Malmö, 20502, Sweden
| | - Claes B Wollheim
- Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden.,Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, 1211, Switzerland
| | - Lena Eliasson
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
| | - Jonathan L S Esguerra
- Islet Cell Exocytosis, Department of Clinical Sciences-Malmö, Lund University, Malmö, 205 02, Sweden.,Lund University Diabetes Centre, Skåne University Hospital, Lund and Malmö, Sweden
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Nagashima K, Tanaka D, Inagaki N. Epidemiology, clinical characteristics, and genetic etiology of neonatal diabetes in Japan. Pediatr Int 2017; 59:129-133. [PMID: 27809389 DOI: 10.1111/ped.13199] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 08/12/2016] [Accepted: 09/20/2016] [Indexed: 11/29/2022]
Abstract
Neonatal diabetes mellitus (NDM) is a rare but potentially devastating metabolic disorder, with a reported incidence of one per 300 000-500 000 births generally, and hyperglycemia develops within the first 6 months of life. NDM is classified into two categories clinically. One is transient NDM (TNDM), in which insulin secretion is spontaneously recovered by several months of age, but sometimes recurs later, and the other is permanent NDM (PNDM), requiring lifelong medication. Recent molecular analysis of NDM identified at least 12 genetic abnormalities: chromosome 6q24, KCNJ11, ABCC8, INS, FOXP3, GCK, IPF1, PTF1A, EIF2AK3, GLUT2, HNF1β, and GLIS3. Of these, imprinting defects on chromosome 6q24 and the KCNJ11 mutation have been recognized as the major causes of TNDM and PNDM, respectively, in Caucasian subjects. Although the pathogenesis and epidemiology of NDM in Japan seem to be clinically distinct, they are still unclear. In this review, we summarize the epidemiology, clinical characteristics, and genetic etiology in Japanese patients with NDM compared with the data on Caucasian patients.
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Affiliation(s)
- Kazuaki Nagashima
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Daisuke Tanaka
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobuya Inagaki
- Department of Diabetes, Endocrinology and Nutrition, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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62
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Genetic Factors of Diabetes. Arch Immunol Ther Exp (Warsz) 2017; 64:157-160. [DOI: 10.1007/s00005-016-0432-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 10/24/2016] [Indexed: 12/30/2022]
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Liver glucose metabolism in humans. Biosci Rep 2016; 36:BSR20160385. [PMID: 27707936 PMCID: PMC5293555 DOI: 10.1042/bsr20160385] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 09/19/2016] [Accepted: 10/04/2016] [Indexed: 12/16/2022] Open
Abstract
Information about normal hepatic glucose metabolism may help to understand pathogenic mechanisms underlying obesity and diabetes mellitus. In addition, liver glucose metabolism is involved in glycosylation reactions and connected with fatty acid metabolism. The liver receives dietary carbohydrates directly from the intestine via the portal vein. Glucokinase phosphorylates glucose to glucose 6-phosphate inside the hepatocyte, ensuring that an adequate flow of glucose enters the cell to be metabolized. Glucose 6-phosphate may proceed to several metabolic pathways. During the post-prandial period, most glucose 6-phosphate is used to synthesize glycogen via the formation of glucose 1-phosphate and UDP–glucose. Minor amounts of UDP–glucose are used to form UDP–glucuronate and UDP–galactose, which are donors of monosaccharide units used in glycosylation. A second pathway of glucose 6-phosphate metabolism is the formation of fructose 6-phosphate, which may either start the hexosamine pathway to produce UDP-N-acetylglucosamine or follow the glycolytic pathway to generate pyruvate and then acetyl-CoA. Acetyl-CoA may enter the tricarboxylic acid (TCA) cycle to be oxidized or may be exported to the cytosol to synthesize fatty acids, when excess glucose is present within the hepatocyte. Finally, glucose 6-phosphate may produce NADPH and ribose 5-phosphate through the pentose phosphate pathway. Glucose metabolism supplies intermediates for glycosylation, a post-translational modification of proteins and lipids that modulates their activity. Congenital deficiency of phosphoglucomutase (PGM)-1 and PGM-3 is associated with impaired glycosylation. In addition to metabolize carbohydrates, the liver produces glucose to be used by other tissues, from glycogen breakdown or from de novo synthesis using primarily lactate and alanine (gluconeogenesis).
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Rabbone I, Barbetti F, Marigliano M, Bonfanti R, Piccinno E, Ortolani F, Ignaccolo G, Maffeis C, Confetto S, Cerutti F, Zanfardino A, Iafusco D. Successful treatment of young infants presenting neonatal diabetes mellitus with continuous subcutaneous insulin infusion before genetic diagnosis. Acta Diabetol 2016; 53:559-65. [PMID: 26831749 DOI: 10.1007/s00592-015-0828-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 12/10/2015] [Indexed: 11/30/2022]
Abstract
AIMS Neonatal diabetes mellitus (NDM) is defined as hyperglycemia and impaired insulin secretion with onset within 6 months of birth. While rare, NDM presents complex challenges regarding the management of glycemic control. The availability of continuous subcutaneous insulin infusion pumps (CSII) in combination with continuous glucose monitoring systems (CGM) provides an opportunity to monitor glucose levels more closely and deliver insulin more safely. METHODS We report four cases of young infants with NDM successfully treated with CSII and CGM. Moreover, in two cases with Kir 6.2 mutation, we describe the use of CSII in switching therapy from insulin to sulfonylurea treatment. RESULTS Insulin pump requirement for the 4 neonatal diabetes cases was the same regardless of disease pathogenesis and c-peptide levels. No dilution of insulin was needed. The use of an integrated CGM system helped in a more precise control of BG levels with the possibility of several modifications of insulin basal rates. Moreover, as showed in the first two case-reports, when the treatment was switched from insulin to glibenclamide, according to identification of Kir 6.2 mutation and diagnosis of NPDM, the CSII therapy demonstrated to be helpful in allowing gradual insulin suspension and progressive introduction of sulfonylurea. CONCLUSIONS During the neonatal period, the use of CSII therapy is safe, more physiological, accurate and easier for the insulin administration management. Furthermore, CSII therapy is safe during the switch of therapy from insulin to glibenclamide for infants with permanent neonatal diabetes mellitus.
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Affiliation(s)
- Ivana Rabbone
- Department of Pediatrics, Regina Margherita Hospital, University of Turin, Piazza Polonia 94, Turin, Italy.
| | - Fabrizio Barbetti
- Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy
- Bambino Gesù Children Hospital, IRCCS, Rome, Italy
| | - Marco Marigliano
- Regional Center for Pediatric Diabetes, Pediatric Diabetes and Metabolic Disorders Unit, University of Verona, Verona, Italy
| | - Riccardo Bonfanti
- Department of Pediatrics, Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Elvira Piccinno
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children's Hospital, Bari, Italy
| | - Federica Ortolani
- Department of Metabolic Diseases, Clinical Genetics and Diabetology, Giovanni XXIII Children's Hospital, Bari, Italy
| | - Giovanna Ignaccolo
- Department of Pediatrics, Regina Margherita Hospital, University of Turin, Piazza Polonia 94, Turin, Italy
| | - Claudio Maffeis
- Regional Center for Pediatric Diabetes, Pediatric Diabetes and Metabolic Disorders Unit, University of Verona, Verona, Italy
| | - Santino Confetto
- Regional Center for Pediatric Diabetes "G.Stoppoloni", Department of Pediatrics, Second University of Naples, Naples, Italy
| | - Franco Cerutti
- Department of Pediatrics, Regina Margherita Hospital, University of Turin, Piazza Polonia 94, Turin, Italy
| | - Angela Zanfardino
- Regional Center for Pediatric Diabetes "G.Stoppoloni", Department of Pediatrics, Second University of Naples, Naples, Italy
| | - Dario Iafusco
- Regional Center for Pediatric Diabetes "G.Stoppoloni", Department of Pediatrics, Second University of Naples, Naples, Italy
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Vinod M, Patankar JV, Sachdev V, Frank S, Graier WF, Kratky D, Kostner GM. MiR-206 is expressed in pancreatic islets and regulates glucokinase activity. Am J Physiol Endocrinol Metab 2016; 311:E175-E185. [PMID: 27221121 PMCID: PMC4941929 DOI: 10.1152/ajpendo.00510.2015] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 05/17/2016] [Indexed: 01/10/2023]
Abstract
Glucose homeostasis is a complex indispensable process, and its dysregulation causes hyperglycemia and type 2 diabetes mellitus. Glucokinase (GK) takes a central role in these pathways and is thus rate limiting for glucose-stimulated insulin secretion (GSIS) from pancreatic islets. Several reports have described the transcriptional regulation of Gck mRNA, whereas its posttranscriptional mechanisms of regulation, especially those involving microRNAs (miR), are poorly understood. In this study, we investigated the role of miR-206 as a posttranscriptional regulator of Gck In addition, we examined the effects of miR-206 on glucose tolerance, GSIS, and gene expression in control and germ line miR-206 knockout (KO) mice fed either with chow or high-fat diet (HFD). MiR-206 was found in Gck-expressing tissues and was differentially altered in response to HFD feeding. Pancreatic islets showed the most profound induction in the expression of miR-206 in response to HFD. Chow- and HFD-fed miR-206KO mice have improved glucose tolerance and GSIS but unaltered insulin sensitivity. In silico analysis of Gck mRNA revealed a conserved 8-mer miR-206 binding site. Hence, the predicted regulation of Gck by miR-206 was confirmed in reporter and GK activity assays. Concomitant with increased GK activity, miR-206KO mice had elevated liver glycogen content and plasma lactate concentrations. Our findings revealed a novel mechanism of posttranscriptional regulation of Gck by miR-206 and underline the crucial role of pancreatic islet miR-206 in the regulation of whole body glucose homeostasis in a murine model that mimics the metabolic syndrome.
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Affiliation(s)
- Manjula Vinod
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Jay V Patankar
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Vinay Sachdev
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Saša Frank
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Dagmar Kratky
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Gerhard M Kostner
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
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Flannick J, Johansson S, Njølstad PR. Common and rare forms of diabetes mellitus: towards a continuum of diabetes subtypes. Nat Rev Endocrinol 2016; 12:394-406. [PMID: 27080136 DOI: 10.1038/nrendo.2016.50] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Insights into the genetic basis of type 2 diabetes mellitus (T2DM) have been difficult to discern, despite substantial research. More is known about rare forms of diabetes mellitus, several of which share clinical and genetic features with the common form of T2DM. In this Review, we discuss the extent to which the study of rare and low-frequency mutations in large populations has begun to bridge the gap between rare and common forms of diabetes mellitus. We hypothesize that the perceived division between these diseases might be due, in part, to the historical ascertainment bias of genetic studies, rather than a clear distinction between disease pathophysiologies. We also discuss possible implications of a new model for the genetic basis of diabetes mellitus subtypes, where the boundary between subtypes becomes blurred.
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Affiliation(s)
- Jason Flannick
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, 415 Main Street, Cambridge, Massachusetts 02142, USA
- Center for Human Genetic Research, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA
| | - Stefan Johansson
- K.G. Jebsen Center for Diabetes Research, The Department of Clinical Science, University of Bergen, Jonas Lies veg 87, N-5020 Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Jonas Lies veg 65, N-5021 Bergen, Norway
| | - Pål R Njølstad
- K.G. Jebsen Center for Diabetes Research, The Department of Clinical Science, University of Bergen, Jonas Lies veg 87, N-5020 Bergen, Norway
- Department of Pediatrics, Haukeland University Hospital, Jonas Lies veg 65, N-5021 Bergen, Norway
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Abstract
It is increasingly recognised that diabetes in young adults has a wide differential diagnosis. There are many monogenic causes, including monogenic beta-cell dysfunction, mitochondrial diabetes and severe insulin resistance. Type 2 diabetes in the young is becoming more prevalent, particularly after adolescence. It's important to understand the clinical features and diagnostic tools available to classify the different forms of young adult diabetes. Classic type 1 diabetes is characterised by positive β-cell antibodies and absence of endogenous insulin secretion. Young type 2 diabetes is accompanied by metabolic syndrome with obesity, hypertension and dyslipidaemia. Monogenic β-cell dysfunction is characterised by non-autoimmune, C-peptide positive diabetes with a strong family history, while mitochondrial diabetes features deafness and other neurological involvement. Severe insulin resistance involves a young-onset metabolic syndrome often with a disproportionately low BMI. A suspected diagnosis of monogenic diabetes is confirmed with genetic testing, which is widely available in specialist centres across the world. Treatment of young adult diabetes is similarly diverse. Mutations in the transcription factors HNF1A and HNF4A and in the β-cell potassium ATP channel components cause diabetes which responds to low dose and high dose sulfonylurea agents, respectively, while glucokinase mutations require no treatment. Monogenic insulin resistance and young-onset type 2 diabetes are both challenging to treat, but first line management involves insulin sensitisers and aggressive management of cardiovascular risk. Outcomes are poor in young-onset type 2 diabetes compared to both older onset type 2 and type 1 diabetes diagnosed at a similar age. The evidence base for treatments in monogenic and young-onset type 2 diabetes relies on studies of moderate quality at best and largely on extrapolation from work conducted in older type 2 diabetes subjects. Better quality, larger studies, particularly of newer agents would improve treatment prospects for young adults with diabetes.
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Fredrick F, Sawe H, Muze K, Mally D, Majaliwa E. A seven weeks old baby with diabetic ketoacidosis: a case report. Clin Case Rep 2016; 4:147-50. [PMID: 26862411 PMCID: PMC4736534 DOI: 10.1002/ccr3.472] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 10/16/2015] [Accepted: 11/05/2015] [Indexed: 11/19/2022] Open
Abstract
Diabetes mellitus is rare during infancy, however, it should be suspected in infants presenting with features consistent with sepsis and hyperglycemia. This is crucial in initiating the treatment of diabetes ketoacidosis which if delayed may result in significant morbidity and death.
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Affiliation(s)
- Francis Fredrick
- Department of Paediatrics Muhimbili National Hospital (MNH) Dar es Salaam Tanzania; Department of Paediatrics and Child Health School of Medicine Muhimbili University of Health and Allied Sciences (MUHAS) Dar es Salaam Tanzania
| | - Hendry Sawe
- Department of Emergency Medicine Muhimbili National Hospital Dar es Salaam Tanzania; Department of Emergency Medicine School of Medicine Muhimbili University of Health and Allied Sciences (MUHAS) Dar es Salaam Tanzania
| | - Kandi Muze
- Department of Paediatrics Muhimbili National Hospital (MNH) Dar es Salaam Tanzania
| | - Deogratius Mally
- Department of Emergency Medicine Muhimbili National Hospital Dar es Salaam Tanzania
| | - Edna Majaliwa
- Department of Paediatrics Muhimbili National Hospital (MNH) Dar es Salaam Tanzania
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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.
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Demirbilek H, Arya VB, Ozbek MN, Houghton JAL, Baran RT, Akar M, Tekes S, Tuzun H, Mackay DJ, Flanagan SE, Hattersley AT, Ellard S, Hussain K. Clinical characteristics and molecular genetic analysis of 22 patients with neonatal diabetes from the South-Eastern region of Turkey: predominance of non-KATP channel mutations. Eur J Endocrinol 2015; 172:697-705. [PMID: 25755231 PMCID: PMC4411707 DOI: 10.1530/eje-14-0852] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 03/09/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes and usually presents in the first 6 months of life. We aimed to describe the clinical characteristics and molecular genetics of a large Turkish cohort of NDM patients from a single centre and estimate an annual incidence rate of NDM in South-Eastern Anatolian region of Turkey. DESIGN AND METHODS NDM patients presenting to Diyarbakir Children State Hospital between 2010 and 2013, and patients under follow-up with presumed type 1 diabetes mellitus, with onset before 6 months of age were recruited. Molecular genetic analysis was performed. RESULTS Twenty-two patients (59% males) were diagnosed with NDM (TNDM-5; PNDM-17). Molecular genetic analysis identified a mutation in 20 (95%) patients who had undergone a mutation analysis. In transient neonatal diabetes (TNDM) patients, the genetic cause included chromosome 6q24 abnormalities (n=3), ABCC8 (n=1) and homozygous INS (n=1). In permanent neonatal diabetes (PNDM) patients, homozygous GCK (n=6), EIF2AK3 (n=3), PTF1A (n=3), and INS (n=1) and heterozygous KCNJ11 (n=2) mutations were identified. Pancreatic exocrine dysfunction was observed in patients with mutations in the distal PTF1A enhancer. Both patients with a KCNJ11 mutation responded to oral sulphonylurea. A variable phenotype was associated with the homozygous c.-331C>A INS mutation, which was identified in both a PNDM and TNDM patient. The annual incidence of PNDM in South-East Anatolian region of Turkey was one in 48 000 live births. CONCLUSIONS Homozygous mutations in GCK, EIF2AK3 and the distal enhancer region of PTF1A were the commonest causes of NDM in our cohort. The high rate of detection of a mutation likely reflects the contribution of new genetic techniques (targeted next-generation sequencing) and increased consanguinity within our cohort.
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Affiliation(s)
- Huseyin Demirbilek
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Ved Bhushan Arya
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Mehmet Nuri Ozbek
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Jayne A L Houghton
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Riza Taner Baran
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Melek Akar
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Selahattin Tekes
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Heybet Tuzun
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Deborah J Mackay
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Sarah E Flanagan
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Andrew T Hattersley
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Sian Ellard
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
| | - Khalid Hussain
- Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK Departments of Paediatric EndocrinologyGreat Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UKThe Institute of Child HealthUniversity College London, London WC1N 1EH, UKDepartments of Paediatric EndocrinologyChildren State Hospital, 21100 Diyarbakir, TurkeyInstitute of Biomedical and Clinical ScienceUniversity of Exeter Medical School, Exeter EX2 5DW, UKDepartments of NeonatologyChildren State Hospital, 21100 Diyarbakir, TurkeyDepartment of Medical Biology and GeneticsDicle University, 21100 Diyarbakir, TurkeyFaculty of MedicineUniversity of Southampton, Southampton SO16 6YD, UK
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Roles of hepatic glucokinase in intertissue metabolic communication: Examination of novel liver-specific glucokinase knockout mice. Biochem Biophys Res Commun 2015; 460:727-32. [PMID: 25817793 DOI: 10.1016/j.bbrc.2015.03.097] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/17/2015] [Indexed: 11/21/2022]
Abstract
Glucokinase is expressed principally in pancreatic β-cells and hepatocytes, and catalyzes the phosphorylation of glucose to glucose-6-phosphate, a rate-limiting step of glycolysis. To better understand the roles of hepatic glucokinase, we generated Gck knockout mice by ablating liver-specific exon 1b. The knockout mice exhibited impaired glucose tolerance, decreased hepatic glycogen content, and reduced Pklr and Fas gene expression in the liver, indicating that hepatic glucokinase plays important roles in glucose metabolism. It has also been reported that hepatic glucokinase regulates the expression of thermogenesis-related genes in brown adipose tissue (BAT) and insulin secretion in response to glucose. However, the liver-specific Gck knockout mice displayed neither altered expression of thermogenesis-related genes in BAT nor impaired insulin secretion by β-cells under a normal chow diet. These results suggest that chronic suppression of hepatic glucokinase has a small influence on intertissue (liver-to-BAT as well as liver-to-β-cell) metabolic communication.
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72
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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.
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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
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73
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Association of the glucokinase gene promoter polymorphism -30G > A (rs1799884) with gestational diabetes mellitus susceptibility: a case-control study and meta-analysis. Arch Gynecol Obstet 2015; 292:291-8. [PMID: 25633883 DOI: 10.1007/s00404-015-3635-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/22/2015] [Indexed: 12/23/2022]
Abstract
PURPOSE Several studies have examined the association between glucokinase (GCK)-30G > A polymorphism and gestational diabetes mellitus (GDM). However, the results are still controversial. We performed the case-control study to investigate whether GCK-30G > A polymorphism correlates with the susceptibility of GDM in Chinese populations, and then conducted a meta-analysis by combining the previous studies. METHODS We recruited 948 GDM patients and 975 controls from May 2011 to August 2013. All the subjects were genotyped using the PCR-based invader assay. The differences of allelic frequencies and genotype distributions between GDM patients and controls were investigated in case-control study. A systematic search of all relevant studies was conducted. The observational studies that were related to an association between the glucokinase (GCK)-30G > A polymorphism and GDM were identified. The association between the glucokinase (GCK)-30G > A polymorphism and GDM susceptibility was assessed using genetic models. RESULTS The case-control study showed that GCK-30G > A polymorphism was associated with the susceptibility of GDM in a Chinese population. Furthermore, other six previously reported studies were included to perform meta-analysis. The meta-analysis showed that GCK-30G > A polymorphism was associated with GDM in Caucasian and Asian. CONCLUSIONS This study suggested that GCK-30G > A polymorphism may be associated with the susceptibility of GDM in a Chinese population. The further meta-analysis provides additional evidence supporting the above result that the risk allele of the GCK-30G > A polymorphism may increase GDM risk.
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74
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Esquiaveto-Aun AM, De Mello MP, Paulino MFVM, Minicucci WJ, Guerra-Júnior G, De Lemos-Marini SHV. A new compound heterozygosis for inactivating mutations in the glucokinase gene as cause of permanent neonatal diabetes mellitus (PNDM) in double-first cousins. Diabetol Metab Syndr 2015; 7:101. [PMID: 26587058 PMCID: PMC4652399 DOI: 10.1186/s13098-015-0101-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/05/2015] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Permanent neonatal diabetes mellitus (PNDM) is a rare disorder, characterized by uncontrolled hyperglycemia diagnosed during the first 6 months of life. In general, PNDM has a genetic origin and most frequently it results from heterozygous mutations in KCNJ11, INS and ABCC8 genes. Homozygous or compound heterozygous inactivating mutations in GCK gene as cause of PNDM are rare. In contrast, heterozygosis for GCK inactivating mutations is frequent and results in the maturity-onset diabetes of young (MODY), manifested by a mild fasting hyperglycemia usually detected later in life. Therefore, as an autosomal recessive disorder, GCK-PNDM should be considered in families with history of glucose intolerance or MODY in first relatives, especially when consanguinity is suspected. RESULTS Here we describe two patients born from non-consanguineous parents within a family. They presented low birth weight with persistent hyperglycemia during the first month of life. Molecular analyses for KCNJ11, INS, ABCC8 did not show any mutation. GCK gene sequencing, however, revealed that both patients were compound heterozygous for two missense combined in a novel GCK-PNDM genotype. The p.Asn254His and p.Arg447Gly mutations had been inherited from their mothers and fathers, respectively, as their mothers are sisters and their fathers are brothers. Parents had been later diagnosed as having GCK-MODY. CONCLUSIONS Mutations' in silico analysis was carried out to elucidate the role of the amino acid changes on the enzyme structure. Both p.Asn254His and p.Arg447Gly mutations appeared to be quite damaging. This is the first report of GCK-PNDM in a Brazilian family.
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Affiliation(s)
- Adriana Mangue Esquiaveto-Aun
- />Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas (UNICAMP), Campinas, SP Brazil
- />Center of Molecular Biology and Genetic Engineering (CBMEG), UNICAMP, Campinas, Brazil
- />Center for Investigation in Pediatrics (CIPED), FCM, UNICAMP, Campinas, Brazil
| | | | | | - Walter José Minicucci
- />Division of Endocrinology, Department of Clinical Medicine, FCM, UNICAMP, Campinas, Brazil
| | - Gil Guerra-Júnior
- />Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas (UNICAMP), Campinas, SP Brazil
- />Center for Investigation in Pediatrics (CIPED), FCM, UNICAMP, Campinas, Brazil
| | - Sofia Helena Valente De Lemos-Marini
- />Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas (UNICAMP), Campinas, SP Brazil
- />Center for Investigation in Pediatrics (CIPED), FCM, UNICAMP, Campinas, Brazil
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75
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Gilon P, Chae HY, Rutter GA, Ravier MA. Calcium signaling in pancreatic β-cells in health and in Type 2 diabetes. Cell Calcium 2014; 56:340-61. [DOI: 10.1016/j.ceca.2014.09.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/26/2014] [Accepted: 09/01/2014] [Indexed: 12/24/2022]
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Hraha TH, Westacott MJ, Pozzoli M, Notary AM, McClatchey PM, Benninger RKP. Phase transitions in the multi-cellular regulatory behavior of pancreatic islet excitability. PLoS Comput Biol 2014; 10:e1003819. [PMID: 25188228 PMCID: PMC4154652 DOI: 10.1371/journal.pcbi.1003819] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/16/2014] [Indexed: 12/23/2022] Open
Abstract
The pancreatic islets of Langerhans are multicellular micro-organs integral to maintaining glucose homeostasis through secretion of the hormone insulin. β-cells within the islet exist as a highly coupled electrical network which coordinates electrical activity and insulin release at high glucose, but leads to global suppression at basal glucose. Despite its importance, how network dynamics generate this emergent binary on/off behavior remains to be elucidated. Previous work has suggested that a small threshold of quiescent cells is able to suppress the entire network. By modeling the islet as a Boolean network, we predicted a phase-transition between globally active and inactive states would emerge near this threshold number of cells, indicative of critical behavior. This was tested using islets with an inducible-expression mutation which renders defined numbers of cells electrically inactive, together with pharmacological modulation of electrical activity. This was combined with real-time imaging of intracellular free-calcium activity [Ca2+]i and measurement of physiological parameters in mice. As the number of inexcitable cells was increased beyond ∼15%, a phase-transition in islet activity occurred, switching from globally active wild-type behavior to global quiescence. This phase-transition was also seen in insulin secretion and blood glucose, indicating physiological impact. This behavior was reproduced in a multicellular dynamical model suggesting critical behavior in the islet may obey general properties of coupled heterogeneous networks. This study represents the first detailed explanation for how the islet facilitates inhibitory activity in spite of a heterogeneous cell population, as well as the role this plays in diabetes and its reversal. We further explain how islets utilize this critical behavior to leverage cellular heterogeneity and coordinate a robust insulin response with high dynamic range. These findings also give new insight into emergent multicellular dynamics in general which are applicable to many coupled physiological systems, specifically where inhibitory dynamics result from coupled networks. As science has successfully broken down the elements of many biological systems, the network dynamics of large-scale cellular interactions has emerged as a new frontier. One way to understand how dynamical elements within large networks behave collectively is via mathematical modeling. Diabetes, which is of increasing international concern, is commonly caused by a deterioration of these complex dynamics in a highly coupled micro-organ called the islet of Langerhans. Therefore, if we are to understand diabetes and how to treat it, we must understand how coupling affects ensemble dynamics. While the role of network connectivity in islet excitation under stimulatory conditions has been well studied, how connectivity also suppresses activity under fasting conditions remains to be elucidated. Here we use two network models of islet connectivity to investigate this process. Using genetically altered islets and pharmacological treatments, we show how suppression of islet activity is solely dependent on a threshold number of inactive cells. We found that the islet exhibits critical behavior in the threshold region, rapidly transitioning from global activity to inactivity. We therefore propose how the islet and multicellular systems in general can generate a robust stimulated response from a heterogeneous cell population.
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Affiliation(s)
- Thomas H. Hraha
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Matthew J. Westacott
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Marina Pozzoli
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Aleena M. Notary
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - P. Mason McClatchey
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Richard K. P. Benninger
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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77
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Rubio-Cabezas O, Hattersley AT, Njølstad PR, Mlynarski W, Ellard S, White N, Chi DV, Craig ME. ISPAD Clinical Practice Consensus Guidelines 2014. The diagnosis and management of monogenic diabetes in children and adolescents. Pediatr Diabetes 2014; 15 Suppl 20:47-64. [PMID: 25182307 DOI: 10.1111/pedi.12192] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 12/18/2022] Open
Affiliation(s)
- Oscar Rubio-Cabezas
- Department of Paediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Madrid, Spain
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Craig ME, Jefferies C, Dabelea D, Balde N, Seth A, Donaghue KC. ISPAD Clinical Practice Consensus Guidelines 2014. Definition, epidemiology, and classification of diabetes in children and adolescents. Pediatr Diabetes 2014; 15 Suppl 20:4-17. [PMID: 25182305 DOI: 10.1111/pedi.12186] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/16/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- Maria E Craig
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead and University of Sydney, Sydney, Australia; School of Women's and Children's Health, University of New South Wales, Sydney, Australia
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79
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Abstract
In this review we highlight recently disclosed progress in the field of small-molecule activators of the human glucokinase enzyme. Several of the reported chemotypes possess structural features that diverge from known leads; some of these modifications appear to be specifically designed to modulate tissue selectivity or discrete parameters of enzyme function (e.g., S0.5 v Vmax). This review will inform the reader of the extent of continued effort being directed toward discovery of a first-in-class drug for Type II diabetes mellitus that functions through this target. Patents were selected from those published in December 2009 up to November 2011; foreign filings were translated where possible to understand the claims and biological techniques utilized to characterize the reported glucokinase activators. Overall, there appears to be a recent trend leading to reduced patent filings for small-molecule glucokinase activators. There are many possible explanations for this trend; however, it is likely that the field has reached maturity and that the downturn of new disclosures represents the transition of many of these programs to the clinic.
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80
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Raimondo A, Chakera AJ, Thomsen SK, Colclough K, Barrett A, De Franco E, Chatelas A, Demirbilek H, Akcay T, Alawneh H, Flanagan SE, Van De Bunt M, Hattersley AT, Gloyn AL, Ellard S. Phenotypic severity of homozygous GCK mutations causing neonatal or childhood-onset diabetes is primarily mediated through effects on protein stability. Hum Mol Genet 2014; 23:6432-40. [PMID: 25015100 PMCID: PMC4240195 DOI: 10.1093/hmg/ddu360] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mutations in glucokinase (GCK) cause a spectrum of glycemic disorders. Heterozygous loss-of-function mutations cause mild fasting hyperglycemia irrespective of mutation severity due to compensation from the unaffected allele. Conversely, homozygous loss-of-function mutations cause permanent neonatal diabetes requiring lifelong insulin treatment. This study aimed to determine the relationship between in vitro mutation severity and clinical phenotype in a large international case series of patients with homozygous GCK mutations. Clinical characteristics for 30 patients with diabetes due to homozygous GCK mutations (19 unique mutations, including 16 missense) were compiled and assigned a clinical severity grade (CSG) based on birth weight and age at diagnosis. The majority (28 of 30) of subjects were diagnosed before 9 months, with the remaining two at 9 and 15 years. These are the first two cases of a homozygous GCK mutation diagnosed outside infancy. Recombinant mutant GCK proteins were analyzed for kinetic and thermostability characteristics and assigned a relative activity index (RAI) or relative stability index (RSI) value. Six of 16 missense mutations exhibited severe kinetic defects (RAI ≤ 0.01). There was no correlation between CSG and RAI (r(2) = 0.05, P = 0.39), indicating that kinetics alone did not explain the phenotype. Eighty percent of the remaining mutations showed reduced thermostability, the exceptions being the two later-onset mutations which exhibited increased thermostability. Comparison of CSG with RSI detected a highly significant correlation (r(2) = 0.74, P = 0.002). We report the largest case series of homozygous GCK mutations to date and demonstrate that they can cause childhood-onset diabetes, with protein instability being the major determinant of mutation severity.
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Affiliation(s)
- Anne Raimondo
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Ali J Chakera
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK, Macleod Diabetes and Endocrine Centre and
| | - Soren K Thomsen
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Kevin Colclough
- Molecular Genetics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Amy Barrett
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Alisson Chatelas
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Huseyin Demirbilek
- Department of Paediatric Endocrinology, Diyarbakir Children State Hospital, Diyarbakir 21100, Turkey
| | - Teoman Akcay
- Division of Pediatric Endocrinology, Dr Sadi Konuk Education and Research Hospital, Bakirkoy, Istanbul 34147, Turkey
| | - Hussein Alawneh
- Pediatric Endocrine Division, Queen Rania Al Abdullah Hospital for Children, King Hussein Medical Center, Royal Medical Services, Amman 11814, Jordan and
| | | | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Martijn Van De Bunt
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK, Macleod Diabetes and Endocrine Centre and
| | - Anna L Gloyn
- Oxford Centre for Diabetes Endocrinology & Metabolism, University of Oxford, Oxford OX3 7LE, UK, Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford OX3 7LE, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK, Molecular Genetics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter EX2 5DW, UK
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81
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Analysis of the co-operative interaction between the allosterically regulated proteins GK and GKRP using tryptophan fluorescence. Biochem J 2014; 459:551-64. [PMID: 24568320 PMCID: PMC4109836 DOI: 10.1042/bj20131363] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hepatic glucose phosphorylation by GK (glucokinase) is regulated by GKRP (GK regulatory protein). GKRP forms a cytosolic complex with GK followed by nuclear import and storage, leading to inhibition of GK activity. This process is initiated by low glucose, but reversed nutritionally by high glucose and fructose or pharmacologically by GKAs (GK activators) and GKRPIs (GKRP inhibitors). To study the regulation of this process by glucose, fructose-phosphate esters and a GKA, we measured the TF (tryptophan fluorescence) of human WT (wild-type) and GKRP-P446L (a mutation associated with high serum triacylglycerol) in the presence of non-fluorescent GK with its tryptophan residues mutated. Titration of GKRP-WT by GK resulted in a sigmoidal increase in TF, suggesting co-operative PPIs (protein-protein interactions) perhaps due to the hysteretic nature of GK. The affinity of GK for GKRP was decreased and binding co-operativity increased by glucose, fructose 1-phosphate and GKA, reflecting disruption of the GK-GKRP complex. Similar studies with GKRP-P446L showed significantly different results compared with GKRP-WT, suggesting impairment of complex formation and nuclear storage. The results of the present TF-based biophysical analysis of PPIs between GK and GKRP suggest that hepatic glucose metabolism is regulated by a metabolite-sensitive drug-responsive co-operative molecular switch, involving complex formation between these two allosterically regulated proteins.
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82
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Nguyen LM, Pozzoli M, Hraha TH, Benninger RK. Decreasing cx36 gap junction coupling compensates for overactive KATP channels to restore insulin secretion and prevent hyperglycemia in a mouse model of neonatal diabetes. Diabetes 2014; 63:1685-97. [PMID: 24458355 PMCID: PMC3994954 DOI: 10.2337/db13-1048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 01/08/2014] [Indexed: 11/13/2022]
Abstract
Mutations to the ATP-sensitive K(+) channel (KATP channel) that reduce the sensitivity of ATP inhibition cause neonatal diabetes mellitus via suppression of β-cell glucose-stimulated free calcium activity ([Ca(2+)]i) and insulin secretion. Connexin-36 (Cx36) gap junctions also regulate islet electrical activity; upon knockout of Cx36, β-cells show [Ca(2+)]i elevations at basal glucose. We hypothesized that in the presence of overactive ATP-insensitive KATP channels, a reduction in Cx36 would allow elevations in glucose-stimulated [Ca(2+)]i and insulin secretion to improve glucose homeostasis. To test this, we introduced a genetic knockout of Cx36 into mice that express ATP-insensitive KATP channels and measured glucose homeostasis and islet metabolic, electrical, and insulin secretion responses. In the normal presence of Cx36, after expression of ATP-insensitive KATP channels, blood glucose levels rapidly rose to >500 mg/dL. Islets from these mice showed reduced glucose-stimulated [Ca(2+)]i and no insulin secretion. In mice lacking Cx36 after expression of ATP-insensitive KATP channels, normal glucose levels were maintained. Islets from these mice had near-normal glucose-stimulated [Ca(2+)]i and insulin secretion. We therefore demonstrate a novel mechanism by which islet function can be recovered in a monogenic model of diabetes. A reduction of gap junction coupling allows sufficient glucose-stimulated [Ca(2+)]i and insulin secretion to prevent the emergence of diabetes.
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Affiliation(s)
- Linda M. Nguyen
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, CO
| | - Marina Pozzoli
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, CO
| | - Thomas H. Hraha
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, CO
| | - Richard K.P. Benninger
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, Aurora, CO
- Barbara Davis Center for Childhood Diabetes, University of Colorado, Anschutz Medical Campus, Aurora, CO
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83
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Chang WL, Huang CJ, Lei TH, Niu DM, Chiu CY, Jap TS. A novel mutation of KCNJ11 gene in a patient with permanent neonatal diabetes mellitus. Diabetes Res Clin Pract 2014; 104:e29-32. [PMID: 24468099 DOI: 10.1016/j.diabres.2013.12.058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/07/2013] [Accepted: 12/28/2013] [Indexed: 11/17/2022]
Abstract
A 4-month-old male baby was diagnosed with Permanent Neonatal Diabetes Mellitus. We identified a novel missense heterogeneous mutation in the KCNJ11 gene at codon 167 (aTC→tTC) in a region that corresponds to a predicted intracellular gate of the ATP-sensitive potassium channel.
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Affiliation(s)
- Wei-Lun Chang
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei, Taiwan, ROC
| | - Chun-Jui Huang
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei, Taiwan, ROC
| | - Tsun-Hsiang Lei
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei, Taiwan, ROC
| | - Dau-Ming Niu
- Section of Molecular Genetics, Department of Pediatrics, Taipei, Taiwan, ROC
| | - Chih-Yang Chiu
- Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Tjin-Shing Jap
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei, Taiwan, ROC.
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84
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Abstract
Monogenic diabetes represents a heterogeneous group of disorders resulting from defects in single genes. Defects are categorized primarily into two groups: disruption of β-cell function or a reduction in the number of β-cells. A complex network of transcription factors control pancreas formation, and a dysfunction of regulators high in the hierarchy leads to pancreatic agenesis. Dysfunction among factors further downstream might cause organ hypoplasia, absence of islets of Langerhans or a reduction in the number of β-cells. Many transcription factors have pleiotropic effects, explaining the association of diabetes with other congenital malformations, including cerebellar agenesis and pituitary agenesis. Monogenic diabetes variants are classified conventionally according to age of onset, with neonatal diabetes occurring before the age of 6 months and maturity onset diabetes of the young (MODY) manifesting before the age of 25 years. Recently, certain familial genetic defects were shown to manifest as neonatal diabetes, MODY or even adult onset diabetes. Patients with neonatal diabetes require a thorough genetic work-up in any case, and because extensive phenotypic overlap exists between monogenic, type 2, and type 1 diabetes, genetic analysis will also help improve diagnosis in these cases. Next generation sequencing will facilitate rapid screening, leading to the discovery of digenic and oligogenic diabetes variants, and helping to improve our understanding of the genetics underlying other types of diabetes. An accurate diagnosis remains important, because it might lead to a change in the treatment of affected subjects and influence long-term complications.
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Affiliation(s)
- Valerie M Schwitzgebel
- Pediatric Endocrine and Diabetes UnitDepartment of Child and Adolescent HealthChildren's University HospitalGenevaSwitzerland
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85
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Johnson AK, Gaudio DD. Clinical utility of next-generation sequencing for the molecular diagnosis of monogenic diabetes. Per Med 2014; 11:155-165. [PMID: 29751380 DOI: 10.2217/pme.13.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Monogenic diabetes resulting from mutations that primarily reduce insulin-secreting pancreatic β-cell function accounts for 1-2% of all cases of diabetes, and is genetically and clinically heterogeneous. Currently, genetic testing for monogenic diabetes relies on selection of the appropriate gene for analysis based on the availability of comprehensive phenotypic information, which can be time consuming, costly and can limit the differential diagnosis to a few selected genes. In recent years, the exponential growth in the field of high-throughput capture and sequencing technology has made it possible and cost effective to sequence many genes simultaneously, making it an efficient diagnostic tool for clinically and genetically heterogeneous disorders such as monogenic diabetes. Making a diagnosis of monogenic diabetes is important as it enables more appropriate treatment, better prediction of disease prognosis and progression, and counseling and screening of family members. We provide a concise overview of the genetic etiology of some forms of monogenic diabetes, as well as a discussion of the clinical utility of genetic testing by comprehensive multigene panel using next-generation sequencing methodologies.
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Affiliation(s)
- Amy Knight Johnson
- Department of Human Genetics, University of Chicago, 5841 S Maryland MC0077, Chicago, IL 60637, USA
| | - Daniela Del Gaudio
- Department of Human Genetics, University of Chicago, 5841 S Maryland MC0077, Chicago, IL 60637, USA
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86
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Yang S, Du Q. Association of GCK -30G> a polymorphism with gestational diabetes mellitus and type 2 diabetes mellitus risk: a meta-analysis involving 18 case-control studies. Genet Test Mol Biomarkers 2014; 18:289-98. [PMID: 24520939 DOI: 10.1089/gtmb.2013.0427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE Several studies have examined the association between the GCK -30G>A polymorphism and the risk of gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM). However, inferences from these studies are hindered by their limited statistical power and conflicting results. The aim of this meta-analysis is to provide a relatively comprehensive picture of the association of the GCK -30G>A polymorphism with GDM and T2DM risk. METHODS A literature search for eligible studies published before August 15, 2013, was conducted in PubMed, Embase, Web of Science, Cochrane Library, and CNKI (China National Knowledge Infrastructure). Pooled odds ratios with their corresponding 95% confidence intervals were used to evaluate the strength of the association under a fixed- or random-effect model according to heterogeneity test results. All analyses were performed using Stata software, version 12.0. RESULTS Eighteen case-control studies from 17 published reports were included in this meta-analysis with a total of 2011 patients with GDM, 11,057 with T2DM, and 26,102 healthy controls. For GDM, the combined results showed that the risk allele of the -30G>A polymorphism may be associated with an increased risk of GDM. Stratified analyses showed that the magnitude of the effect was especially significant among whites, indicating ethnicity differences for GDM susceptibility. For T2DM, the pooled ORs were not significant in the overall population, although all the ORs >1 suggested an increased risk of T2DM for carriers of the A allele. However, whites seem to be significantly more susceptible to T2DM than Asians. CONCLUSION This meta-analysis indicated that the risk allele of the GCK -30G>A polymorphism may increase GDM and T2DM risk in whites, whereas additional studies are needed to confirm the effect of this polymorphism on both diseases in Asians and Africans.
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Affiliation(s)
- Sheng Yang
- Department of Endocrinology, Shengjing Hospital of China Medical University , Shenyang, China
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87
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George DCP, Chakraborty C, Haneef SAS, NagaSundaram N, Chen L, Zhu H. Evolution- and structure-based computational strategy reveals the impact of deleterious missense mutations on MODY 2 (maturity-onset diabetes of the young, type 2). Theranostics 2014; 4:366-85. [PMID: 24578721 PMCID: PMC3936290 DOI: 10.7150/thno.7473] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/03/2014] [Indexed: 11/05/2022] Open
Abstract
Heterozygous mutations in the central glycolytic enzyme glucokinase (GCK) can result in an autosomal dominant inherited disease, namely maturity-onset diabetes of the young, type 2 (MODY 2). MODY 2 is characterised by early onset: it usually appears before 25 years of age and presents as a mild form of hyperglycaemia. In recent years, the number of known GCK mutations has markedly increased. As a result, interpreting which mutations cause a disease or confer susceptibility to a disease and characterising these deleterious mutations can be a difficult task in large-scale analyses and may be impossible when using a structural perspective. The laborious and time-consuming nature of the experimental analysis led us to attempt to develop a cost-effective computational pipeline for diabetic research that is based on the fundamentals of protein biophysics and that facilitates our understanding of the relationship between phenotypic effects and evolutionary processes. In this study, we investigate missense mutations in the GCK gene by using a wide array of evolution- and structure-based computational methods, such as SIFT, PolyPhen2, PhD-SNP, SNAP, SNPs&GO, fathmm, and Align GVGD. Based on the computational prediction scores obtained using these methods, three mutations, namely E70K, A188T, and W257R, were identified as highly deleterious on the basis of their effects on protein structure and function. Using the evolutionary conservation predictors Consurf and Scorecons, we further demonstrated that most of the predicted deleterious mutations, including E70K, A188T, and W257R, occur in highly conserved regions of GCK. The effects of the mutations on protein stability were computed using PoPMusic 2.1, I-mutant 3.0, and Dmutant. We also conducted molecular dynamics (MD) simulation analysis through in silico modelling to investigate the conformational differences between the native and the mutant proteins and found that the identified deleterious mutations alter the stability, flexibility, and solvent-accessible surface area of the protein. Furthermore, the functional role of each SNP in GCK was identified and characterised using SNPeffect 4.0, F-SNP, and FASTSNP. We hope that the observed results aid in the identification of disease-associated mutations that affect protein structure and function. Our in silico findings provide a new perspective on the role of GCK mutations in MODY2 from an evolution-based structure-centric point of view. The computational architecture described in this paper can be used to predict the most appropriate disease phenotypes for large-genome sequencing projects and to provide individualised drug therapy for complex diseases such as diabetes.
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Affiliation(s)
- Doss C. Priya George
- 1. Medical Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu 632014, India
| | - Chiranjib Chakraborty
- 2. Department of Computer Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong
- 3. Department of Bioinformatics, School of Computer and Information sciences, Galgotias University, India
| | - SA Syed Haneef
- 1. Medical Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu 632014, India
| | - Nagarajan NagaSundaram
- 1. Medical Biotechnology Division, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu 632014, India
| | - Luonan Chen
- 4. Key Laboratory of Systems Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, China
| | - Hailong Zhu
- 2. Department of Computer Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong
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88
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Negahdar M, Aukrust I, Molnes J, Solheim MH, Johansson BB, Sagen JV, Dahl-Jørgensen K, Kulkarni RN, Søvik O, Flatmark T, Njølstad PR, Bjørkhaug L. GCK-MODY diabetes as a protein misfolding disease: the mutation R275C promotes protein misfolding, self-association and cellular degradation. Mol Cell Endocrinol 2014; 382:55-65. [PMID: 24001579 DOI: 10.1016/j.mce.2013.08.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 11/28/2022]
Abstract
GCK-MODY, dominantly inherited mild hyperglycemia, is associated with more than 600 mutations in the glucokinase gene. Different molecular mechanisms have been shown to explain GCK-MODY. Here, we report a Pakistani family harboring the glucokinase mutation c.823C>T (p.R275C). The recombinant and in cellulo expressed mutant pancreatic enzyme revealed slightly increased enzyme activity (kcat) and normal affinity for α-D-glucose, and resistance to limited proteolysis by trypsin comparable with wild-type. When stably expressed in HEK293 cells and MIN6 β-cells (at different levels), the mutant protein appeared misfolded and unstable with a propensity to form dimers and aggregates. Its degradation rate was increased, involving the lysosomal and proteasomal quality control systems. On mutation, a hydrogen bond between the R275 side-chain and the carbonyl oxygen of D267 is broken, destabilizing the F260-L271 loop structure and the protein. This promotes the formation of dimers/aggregates and suggests that an increased cellular degradation is the molecular mechanism by which R275C causes GCK-MODY.
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Affiliation(s)
- Maria Negahdar
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Ingvild Aukrust
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; Section of Islet Cell Biology and Regenerative Medicine, Joslin Diabetes Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Janne Molnes
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Marie H Solheim
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Bente B Johansson
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Jørn V Sagen
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Institute of Medicine, University of Bergen, Bergen, Norway; Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Knut Dahl-Jørgensen
- Pediatric Department Ullevaal, Oslo University Hospital, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Rohit N Kulkarni
- Section of Islet Cell Biology and Regenerative Medicine, Joslin Diabetes Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Oddmund Søvik
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - Pål R Njølstad
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.
| | - Lise Bjørkhaug
- KG Jebsen Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway; Department of Biomedicine, University of Bergen, Bergen, Norway
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89
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Flanagan SE, De Franco E, Lango Allen H, Zerah M, Abdul-Rasoul MM, Edge JA, Stewart H, Alamiri E, Hussain K, Wallis S, de Vries L, Rubio-Cabezas O, Houghton JAL, Edghill EL, Patch AM, Ellard S, Hattersley AT. Analysis of transcription factors key for mouse pancreatic development establishes NKX2-2 and MNX1 mutations as causes of neonatal diabetes in man. Cell Metab 2014; 19:146-54. [PMID: 24411943 PMCID: PMC3887257 DOI: 10.1016/j.cmet.2013.11.021] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 08/05/2013] [Accepted: 11/15/2013] [Indexed: 12/29/2022]
Abstract
Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development.
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Affiliation(s)
- Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Hana Lango Allen
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Michele Zerah
- Presbyterian Medical Group, Albuquerque, NM 87106, USA
| | | | - Julie A Edge
- Oxford Children's Hospital, Headington, Oxford OX3 9DU, UK
| | - Helen Stewart
- Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford OX3 7LE, UK
| | - Elham Alamiri
- Al Qassimi Hospital, Sharjah 3500, United Arab Emirates
| | - Khalid Hussain
- London Centre for Paediatric Endocrinology and Metabolism, Great Ormond Street Hospital for Children NHS Trust, and The Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Sam Wallis
- Neonatal Unit, Bradford Royal Infirmary, Bradford BD9 6RJ, UK
| | - Liat de Vries
- Institute of Endocrinology and Diabetes, Schneider Children's Medical Center of Israel, PetahTikva, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 49202, Israel
| | - Oscar Rubio-Cabezas
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK; Department of Paediatric Endocrinology, Hospital Infantil Niño Jesús, Madrid 28009, Spain
| | - Jayne A L Houghton
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Emma L Edghill
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Ann-Marie Patch
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK.
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90
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Afshar M, Han Z. Teaching and Learning Medical Biochemistry: Perspectives from a Student and an Educator. MEDICAL SCIENCE EDUCATOR 2014; 24:339-341. [PMID: 25815241 PMCID: PMC4370413 DOI: 10.1007/s40670-014-0004-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Mehdi Afshar
- Department of Biochemistry and Molecular Medicine, the George Washington University School of Medicine and Health Sciences, Room 547, Ross Hall, 2300 Eye Street NW, Washington, DC 20037 USA
| | - Zhiyong Han
- Department of Biochemistry and Molecular Medicine, the George Washington University School of Medicine and Health Sciences, Room 547, Ross Hall, 2300 Eye Street NW, Washington, DC 20037 USA
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91
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Abstract
Neonatal diabetes mellitus is a rare condition (1/90,000 to 1/260,000 live births) defined as mild-to-severe hyperglycemia within the first year of life. Permanent neonatal diabetes mellitus requires lifelong therapy, whereas transient form resolves early in life but may relapse later on. Two main physiopathological mechanisms may explain this disease: β cell functional impairment or absence (pancreas agenesis or β cells destruction). The main genetic causes of β cells impairment are 6q24 abnormalities and mutations in ABCC8 or KCNJ11 potassium channel (KATP channel) genes. Compared to the KATP subtype, the 6q24 subtype had specific features: developmental defects involving the heart, kidneys, or urinary tract, intrauterine growth restriction, and early diagnosis. Remission of neonatal diabetes mellitus occurred in 51% of probands at a median age of 17 weeks. Recurrence was common at pubertal age, with no difference between the 6q24 and KATP-channel groups (82% vs 86%, p=0.36, respectively). Patients with mutations in ABCC8 or KCNJ11 genes had developmental delay with or without epilepsy but also developmental coordination disorder (particularly visual-spatial dyspraxia) or attention deficits in all of those who underwent in-depth neuropsychomotor investigations.
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92
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DellaManna T, Silva MRD, Chacra AR, Kunii IS, Rolim AL, Furuzawa G, Maciel RMDB, Reis AF. Clinical follow-up of two Brazilian subjects with glucokinase-MODY (MODY2) with description of a novel mutation. ACTA ACUST UNITED AC 2013; 56:490-5. [PMID: 23295287 DOI: 10.1590/s0004-27302012000800005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 09/10/2012] [Indexed: 11/22/2022]
Abstract
Mutations in the glucokinase gene (GCK) account for many cases of monogenic diabetes featuring maturity-onset diabetes of the young type 2 (MODY2). The clinical pattern of this form of hyperglycemia is rather stable, with a slight elevation in blood glucose, which is usually not progressive. Patients rarely require pharmacological interventions and microvascular complications related to diabetes are unusual. We describe the clinical follow-up of two cases of MODY2 with two different mutations in GCK gene, one in exon 7, p.Glu265Lys (c.793 G> A), which has been previously described, and a novel one, in exon 2, p.Ser69Stop (c. 206C> G). The clinical course of both cases shows similarity in metabolic control of this form of diabetes over the years.
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Affiliation(s)
- Thais DellaManna
- Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, Brazil
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93
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Teo AKK, Wagers AJ, Kulkarni RN. New opportunities: harnessing induced pluripotency for discovery in diabetes and metabolism. Cell Metab 2013; 18:775-91. [PMID: 24035588 PMCID: PMC3858409 DOI: 10.1016/j.cmet.2013.08.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The landmark discovery of induced pluripotent stem cells (iPSCs) by Shinya Yamanaka has transformed regenerative biology. Previously, insights into the pathogenesis of chronic human diseases have been hindered by the inaccessibility of patient samples. However, scientists are now able to convert patient fibroblasts into iPSCs and differentiate them into disease-relevant cell types. This ability opens new avenues for investigating disease pathogenesis and designing novel treatments. In this review, we highlight the uses of human iPSCs to uncover the underlying causes and pathological consequences of diabetes and metabolic syndromes, multifactorial diseases whose etiologies have been difficult to unravel using traditional methodologies.
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Affiliation(s)
- Adrian Kee Keong Teo
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02215, USA
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94
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Abstract
ATP-sensitive potassium channels (K(ATP) channels) link cell metabolism to electrical activity by controlling the cell membrane potential. They participate in many physiological processes but have a particularly important role in systemic glucose homeostasis by regulating hormone secretion from pancreatic islet cells. Glucose-induced closure of K(ATP) channels is crucial for insulin secretion. Emerging data suggest that K(ATP) channels also play a key part in glucagon secretion, although precisely how they do so remains controversial. This Review highlights the role of K(ATP) channels in insulin and glucagon secretion. We discuss how K(ATP) channels might contribute not only to the initiation of insulin release but also to the graded stimulation of insulin secretion that occurs with increasing glucose concentrations. The various hypotheses concerning the role of K(ATP) channels in glucagon release are also reviewed. Furthermore, we illustrate how mutations in K(ATP) channel genes can cause hyposecretion or hypersecretion of insulin, as in neonatal diabetes mellitus and congenital hyperinsulinism, and how defective metabolic regulation of the channel may underlie the hypoinsulinaemia and the hyperglucagonaemia that characterize type 2 diabetes mellitus. Finally, we outline how sulphonylureas, which inhibit K(ATP) channels, stimulate insulin secretion in patients with neonatal diabetes mellitus or type 2 diabetes mellitus, and suggest their potential use to target the glucagon secretory defects found in diabetes mellitus.
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Affiliation(s)
- Frances M Ashcroft
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford OX1 3PT, UK
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95
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Carroll RW, Murphy R. Monogenic diabetes: a diagnostic algorithm for clinicians. Genes (Basel) 2013; 4:522-35. [PMID: 24705260 PMCID: PMC3927568 DOI: 10.3390/genes4040522] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 12/30/2022] Open
Abstract
Monogenic forms of beta cell diabetes account for approximately 1%-2% of all cases of diabetes, yet remain underdiagnosed. Overlapping clinical features with common forms of diabetes, make diagnosis challenging. A genetic diagnosis of monogenic diabetes in many cases alters therapy, affects prognosis, enables genetic counseling, and has implications for cascade screening of extended family members. We describe those types of monogenic beta cell diabetes which are recognisable by distinct clinical features and have implications for altered management; the cost effectiveness of making a genetic diagnosis in this setting; the use of complementary diagnostic tests to increase the yield among the vast majority of patients who will have commoner types of diabetes which are summarised in a clinical algorithm; and the vital role of cascade genetic testing to enhance case finding.
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Affiliation(s)
- Richard W Carroll
- Endocrine, Diabetes and Research Centre, Wellington Regional Hospital, Private Bag 7902, Newtown, Wellington 6021, New Zealand.
| | - Rinki Murphy
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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96
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De Ceuninck F, Kargar C, Ilic C, Caliez A, Rolin JO, Umbdenstock T, Vinson C, Combettes M, de Fanti B, Harley E, Sadlo M, Lefèvre AL, Broux O, Wierzbicki M, Fourquez JM, Perron-Sierra F, Kotschy A, Ktorza A. Small molecule glucokinase activators disturb lipid homeostasis and induce fatty liver in rodents: a warning for therapeutic applications in humans. Br J Pharmacol 2013; 168:339-53. [PMID: 22925001 DOI: 10.1111/j.1476-5381.2012.02184.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/23/2012] [Accepted: 08/03/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Small-molecule glucokinase activators (GKAs) are currently being investigated as therapeutic options for the treatment of type 2 diabetes (T2D). Because liver overexpression of glucokinase is thought to be associated with altered lipid profiles, this study aimed at assessing the potential lipogenic risks linked to oral GKA administration. EXPERIMENTAL APPROACH Nine GKA candidates were qualified for their ability to activate recombinant glucokinase and to stimulate glycogen synthesis in rat hepatocytes and insulin secretion in rat INS-1E cells. In vivo activity was monitored by plasma glucose and HbA1c measurements after oral administration in rodents. Risk-associated effects were assessed by measuring hepatic and plasma triglycerides and free fatty acids, as well as plasma aminotransferases, and alkaline phosphatase. KEY RESULTS GKAs, while efficiently decreasing glycaemia in acute conditions and HbA1c levels after chronic administration in hyperglycemic db/db mice, were potent inducers of hepatic steatosis. This adverse outcome appeared as soon as 4 days after daily oral administration at pharmacological doses and was not transient. GKA treatment similarly increased hepatic triglycerides in diabetic and normoglycaemic rats, together with a pattern of metabolic phenotypes including different combinations of increased plasma triglycerides, free fatty acids, alanine and aspartyl aminotransferases, and alkaline phosphatase. GKAs belonging to three distinct structural families induced hepatic steatosis in db/db mice, arguing in favour of a target-mediated, rather than a chemical class-mediated, effect. CONCLUSION AND IMPLICATIONS Given the risks associated with fatty liver disease in the general population and furthermore in patients with T2D, these findings represent a serious warning for the use of GKAs in humans. LINKED ARTICLE This article is commented on by Rees and Gloyn, pp. 335-338 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2012.02201.x.
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Affiliation(s)
- Frédéric De Ceuninck
- Division of Metabolic Diseases, Institut de Recherches Servier, Suresnes, France.
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97
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Hussain S, Mohd Ali J, Jalaludin MY, Harun F. Permanent neonatal diabetes due to a novel insulin signal peptide mutation. Pediatr Diabetes 2013; 14:299-303. [PMID: 23350652 PMCID: PMC3712474 DOI: 10.1111/pedi.12011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 09/26/2012] [Accepted: 11/02/2012] [Indexed: 11/30/2022] Open
Abstract
We report a rare case of permanent neonatal diabetes (PND) due to insulin (INS) gene mutation in a 51-month-old girl who presented with hyperglycemia in the neonatal period. Mutational analysis of KCNJ11 and INS was performed and this detected a novel heterozygous c.38T>G (p.Leu13Arg) INS de novo mutation. The non-conservative change substitutes the highly conserved L(13) residue within the hydrophobic core region of the preproinsulin signal peptide. Given the frequent tendency of heterozygous INS mutations to exhibit dominant negative disease pathogenesis, it is likely that the mutant preproinsulin perturbed the non-mutant counterpart progression and processing within the β-cells, and this resulted to a permanent form of congenital diabetes.
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Affiliation(s)
- Suhaimi Hussain
- Department of Paediatrics, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.
| | - Johari Mohd Ali
- Department of Molecular Medicine, Faculty of Medicine, University of MalayaKuala Lumpur, Malaysia
| | | | - Fatimah Harun
- Department of Pediatrics, Faculty of Medicine, University of MalayaKuala Lumpur, Malaysia
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98
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Pathogenesis of the metabolic syndrome: insights from monogenic disorders. Mediators Inflamm 2013; 2013:920214. [PMID: 23766565 PMCID: PMC3673346 DOI: 10.1155/2013/920214] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 04/18/2013] [Indexed: 12/16/2022] Open
Abstract
Identifying rare human metabolic disorders that result from a single-gene defect has not only enabled improved diagnostic and clinical management of such patients, but also has resulted in key biological insights into the pathophysiology of the increasingly prevalent metabolic syndrome. Insulin resistance and type 2 diabetes are linked to obesity and driven by excess caloric intake and reduced physical activity. However, key events in the causation of the metabolic syndrome are difficult to disentangle from compensatory effects and epiphenomena. This review provides an overview of three types of human monogenic disorders that result in (1) severe, non-syndromic obesity, (2) pancreatic beta cell forms of early-onset diabetes, and (3) severe insulin resistance. In these patients with single-gene defects causing their exaggerated metabolic disorder, the primary defect is known. The lessons they provide for current understanding of the molecular pathogenesis of the common metabolic syndrome are highlighted.
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99
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Nair VV, Chapla A, Arulappan N, Thomas N. Molecular diagnosis of maturity onset diabetes of the young in India. Indian J Endocrinol Metab 2013; 17:430-441. [PMID: 23869298 PMCID: PMC3712372 DOI: 10.4103/2230-8210.111636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Diabetes is highly prevalent in India and the proportion of younger patients developing diabetes is on the increase. Apart from the more universally known type 1 diabetes and obesity related type 2 diabetes, monogenic forms of diabetes are also suspected to be prevalent in many young diabetic patients. The identification of the genetic basis of the disease not only guides in therapeutic decision making, but also aids in genetic counselling and prognostication. Genetic testing may establish the occurrence and frequency of early diabetes in our population. This review attempts to explore the utilities and horizons of molecular genetics in the field of maturity onset diabetes of the young (MODY), which include the commoner forms of monogenic diabetes.
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Affiliation(s)
- Veena V. Nair
- Department of Endocrinology, Diabetes and Metabolism, Christian Medical College Hospital, Vellore, India
| | - Aaron Chapla
- Department of Endocrinology, Diabetes and Metabolism, Christian Medical College Hospital, Vellore, India
| | - Nishanth Arulappan
- Department of Endocrinology, Diabetes and Metabolism, Christian Medical College Hospital, Vellore, India
| | - Nihal Thomas
- Department of Endocrinology, Diabetes and Metabolism, Christian Medical College Hospital, Vellore, India
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Genetic polymorphism of glucokinase on the risk of type 2 diabetes and impaired glucose regulation: evidence based on 298,468 subjects. PLoS One 2013; 8:e55727. [PMID: 23441155 PMCID: PMC3575415 DOI: 10.1371/journal.pone.0055727] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/29/2012] [Indexed: 12/23/2022] Open
Abstract
Background Glucokinase (GCK) is the key glucose phosphorylation enzyme which has attracted considerable attention as a candidate gene for type 2 diabetes (T2D) based on its enzyme function as the first rate-limiting step in the glycolysis pathway and regulates glucose-stimulated insulin secretion. In the past decade, the relationship between GCK and T2D has been reported in various ethnic groups. To derive a more precise estimation of the relationship and the effect of factors that might modify the risk, we performed this meta-analysis. Methods Databases including Pubmed, EMBASE, Web of Science and China National Knowledge Infrastructure (CNKI) were searched to find relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association. Results A total of 24 articles involving 88, 229 cases and 210, 239 controls were included. An overall random-effects per-allele OR of 1.06 (95% CI: 1.03–1.09; P<10−4) was found for the GCK −30G>A polymorphism. Significant results were also observed using dominant or recessive genetic models. In the subgroup analyses by ethnicity, significant results were found in Caucasians; whereas no significant associations were found among Asians. In addition, we found that the −30G>A polymorphism is a risk factor associated with increased impaired glucose regulation susceptibility. Besides, −30G>A homozygous was found to be significantly associated with increased fasting plasma glucose level with weighted mean difference (WMD) of 0.15 (95%: 0.05–0.24, P = 0.001) compared with G/G genotype. Conclusions This meta-analysis demonstrated that the −30G>A polymorphism of GCK is a risk factor associated with increased T2D susceptibility, but these associations vary in different ethnic populations.
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