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An M, Akyuz M, Capik O, Yalcin C, Bertram R, Karatas EA, Karatas OF, Yildirim V. Gain of function mutation in K(ATP) channels and resulting upregulation of coupling conductance are partners in crime in the impairment of Ca 2+ oscillations in pancreatic ß-cells. Math Biosci 2024; 374:109224. [PMID: 38821258 DOI: 10.1016/j.mbs.2024.109224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 04/30/2024] [Accepted: 05/28/2024] [Indexed: 06/02/2024]
Abstract
Gain of function mutations in the pore forming Kir6 subunits of the ATP sensitive K+ channels (K(ATP) channels) of pancreatic β-cells are the major cause of neonatal diabetes in humans. In this study, we show that in insulin secreting mouse β-cell lines, gain of function mutations in Kir6.1 result in a significant connexin36 (Cx36) overexpression, which form gap junctional connections and mediate electrical coupling between β-cells within pancreatic islets. Using computational modeling, we show that upregulation in Cx36 might play a functional role in the impairment of glucose stimulated Ca2+ oscillations in a cluster of β-cells with Kir6.1 gain of function mutations in their K(ATP) channels (GoF-K(ATP) channels). Our results show that without an increase in Cx36 expression, a gain of function mutation in Kir6.1 might not be sufficient to diminish glucose stimulated Ca2+ oscillations in a β-cell cluster. We also show that a reduced Cx36 expression, which leads to loss of coordination in a wild-type β-cell cluster, restores coordinated Ca2+ oscillations in a β-cell cluster with GoF-K(ATP) channels. Our results indicate that in a heterogenous β-cell cluster with GoF-K(ATP) channels, there is an inverted u-shaped nonmonotonic relation between the cluster activity and Cx36 expression. These results show that in a neonatal diabetic β-cell model, gain of function mutations in the Kir6.1 cause Cx36 overexpression, which aggravates the impairment of glucose stimulated Ca2+ oscillations.
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Affiliation(s)
- Murat An
- Department of Basic Sciences, Erzurum Technical University, Erzurum, Turkey
| | - Mesut Akyuz
- Department of Molecular Biology and Genetics, Erzurum Technical University, Erzurum, Turkey
| | - Ozel Capik
- Department of Molecular Biology and Genetics, Erzurum Technical University, Erzurum, Turkey
| | - Cigdem Yalcin
- Department of Mathematics, Erzurum Technical University, Erzurum, Turkey
| | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida, United States
| | - Elanur Aydin Karatas
- Department of Molecular Biology and Genetics, Erzurum Technical University, Erzurum, Turkey
| | - Omer Faruk Karatas
- Department of Molecular Biology and Genetics, Erzurum Technical University, Erzurum, Turkey
| | - Vehpi Yildirim
- Department of Mathematics, Erzurum Technical University, Erzurum, Turkey; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
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Bauer I, Rimbach G, Cordeiro S, Bosy-Westphal A, Weghuber J, Ipharraguerre IR, Lüersen K. A comprehensive in-vitro/ in-vivo screening toolbox for the elucidation of glucose homeostasis modulating properties of plant extracts (from roots) and its bioactives. Front Pharmacol 2024; 15:1396292. [PMID: 38989154 PMCID: PMC11233739 DOI: 10.3389/fphar.2024.1396292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/10/2024] [Indexed: 07/12/2024] Open
Abstract
Plant extracts are increasingly recognized for their potential in modulating (postprandial) blood glucose levels. In this context, root extracts are of particular interest due to their high concentrations and often unique spectrum of plant bioactives. To identify new plant species with potential glucose-lowering activity, simple and robust methodologies are often required. For this narrative review, literature was sourced from scientific databases (primarily PubMed) in the period from June 2022 to January 2024. The regulatory targets of glucose homeostasis that could be modulated by bioactive plant compounds were used as search terms, either alone or in combination with the keyword "root extract". As a result, we present a comprehensive methodological toolbox for studying the glucose homeostasis modulating properties of plant extracts and its constituents. The described assays encompass in-vitro investigations involving enzyme inhibition (α-amylase, α-glucosidase, dipeptidyl peptidase 4), assessment of sodium-dependent glucose transporter 1 activity, and evaluation of glucose transporter 4 translocation. Furthermore, we describe a patch-clamp technique to assess the impact of extracts on KATP channels. While validating in-vitro findings in living organisms is imperative, we introduce two screenable in-vivo models (the hen's egg test and Drosophila melanogaster). Given that evaluation of the bioactivity of plant extracts in rodents and humans represents the current gold standard, we include approaches addressing this aspect. In summary, this review offers a systematic guide for screening plant extracts regarding their influence on key regulatory elements of glucose homeostasis, culminating in the assessment of their potential efficacy in-vivo. Moreover, application of the presented toolbox might contribute to further close the knowledge gap on the precise mechanisms of action of plant-derived compounds.
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Affiliation(s)
- Ilka Bauer
- Division of Food Sciences, Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - Gerald Rimbach
- Division of Food Sciences, Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - Sönke Cordeiro
- Institute of Physiology, University of Kiel, Kiel, Germany
| | - Anja Bosy-Westphal
- Division of Human Nutrition, Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - Julian Weghuber
- Center of Excellence Food Technology and Nutrition, University of Applied Sciences Upper Austria, Wels, Austria
- FFoQSI—Austrian Competence Centre for Feed and Food Quality, Safety & Innovation, Tulln, Austria
| | - Ignacio R. Ipharraguerre
- Division of Food Sciences, Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
| | - Kai Lüersen
- Division of Food Sciences, Institute of Human Nutrition and Food Science, University of Kiel, Kiel, Germany
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Vedovato N, Salguero MV, Greeley SAW, Yu CH, Philipson LH, Ashcroft FM. A loss-of-function mutation in KCNJ11 causing sulfonylurea-sensitive diabetes in early adult life. Diabetologia 2024; 67:940-951. [PMID: 38366195 PMCID: PMC10954967 DOI: 10.1007/s00125-024-06103-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/28/2023] [Indexed: 02/18/2024]
Abstract
AIMS/HYPOTHESIS The ATP-sensitive potassium (KATP) channel couples beta cell electrical activity to glucose-stimulated insulin secretion. Loss-of-function mutations in either the pore-forming (inwardly rectifying potassium channel 6.2 [Kir6.2], encoded by KCNJ11) or regulatory (sulfonylurea receptor 1, encoded by ABCC8) subunits result in congenital hyperinsulinism, whereas gain-of-function mutations cause neonatal diabetes. Here, we report a novel loss-of-function mutation (Ser118Leu) in the pore helix of Kir6.2 paradoxically associated with sulfonylurea-sensitive diabetes that presents in early adult life. METHODS A 31-year-old woman was diagnosed with mild hyperglycaemia during an employee screen. After three pregnancies, during which she was diagnosed with gestational diabetes, the patient continued to show elevated blood glucose and was treated with glibenclamide (known as glyburide in the USA and Canada) and metformin. Genetic testing identified a heterozygous mutation (S118L) in the KCNJ11 gene. Neither parent was known to have diabetes. We investigated the functional properties and membrane trafficking of mutant and wild-type KATP channels in Xenopus oocytes and in HEK-293T cells, using patch-clamp, two-electrode voltage-clamp and surface expression assays. RESULTS Functional analysis showed no changes in the ATP sensitivity or metabolic regulation of the mutant channel. However, the Kir6.2-S118L mutation impaired surface expression of the KATP channel by 40%, categorising this as a loss-of-function mutation. CONCLUSIONS/INTERPRETATION Our data support the increasing evidence that individuals with mild loss-of-function KATP channel mutations may develop insulin deficiency in early adulthood and even frank diabetes in middle age. In this case, the patient may have had hyperinsulinism that escaped detection in early life. Our results support the importance of functional analysis of KATP channel mutations in cases of atypical diabetes.
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Affiliation(s)
- Natascia Vedovato
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, UK
| | - Maria V Salguero
- Departments of Medicine and Pediatrics, Section of Endocrinology Diabetes and Metabolism, University of Chicago, Chicago, IL, USA
| | - Siri Atma W Greeley
- Departments of Medicine and Pediatrics, Section of Endocrinology Diabetes and Metabolism, University of Chicago, Chicago, IL, USA
| | - Christine H Yu
- Division of Endocrinology, Department of Pediatric Medicine, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Louis H Philipson
- Departments of Medicine and Pediatrics, Section of Endocrinology Diabetes and Metabolism, University of Chicago, Chicago, IL, USA
| | - Frances M Ashcroft
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, UK.
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Sun HY, Lin XY. Genetic perspectives on childhood monogenic diabetes: Diagnosis, management, and future directions. World J Diabetes 2023; 14:1738-1753. [PMID: 38222792 PMCID: PMC10784795 DOI: 10.4239/wjd.v14.i12.1738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 10/10/2023] [Accepted: 11/14/2023] [Indexed: 12/14/2023] Open
Abstract
Monogenic diabetes is caused by one or even more genetic variations, which may be uncommon yet have a significant influence and cause diabetes at an early age. Monogenic diabetes affects 1 to 5% of children, and early detection and gene-tically focused treatment of neonatal diabetes and maturity-onset diabetes of the young can significantly improve long-term health and well-being. The etiology of monogenic diabetes in childhood is primarily attributed to genetic variations affecting the regulatory genes responsible for beta-cell activity. In rare instances, mutations leading to severe insulin resistance can also result in the development of diabetes. Individuals diagnosed with specific types of monogenic diabetes, which are commonly found, can transition from insulin therapy to sulfonylureas, provided they maintain consistent regulation of their blood glucose levels. Scientists have successfully devised materials and methodologies to distinguish individuals with type 1 or 2 diabetes from those more prone to monogenic diabetes. Genetic screening with appropriate findings and interpretations is essential to establish a prognosis and to guide the choice of therapies and management of these interrelated ailments. This review aims to design a comprehensive literature summarizing genetic insights into monogenetic diabetes in children and adolescents as well as summarizing their diagnosis and mana-gement.
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Affiliation(s)
- Hong-Yan Sun
- Department of Endocrine and Metabolic Diseases, Yantaishan Hospital, Yantai 264003, Shandong Province, China
| | - Xiao-Yan Lin
- Department of Endocrine and Metabolic Diseases, Yantaishan Hospital, Yantai 264003, Shandong Province, China
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Alam KA, Svalastoga P, Martinez A, Glennon JC, Haavik J. Potassium channels in behavioral brain disorders. Molecular mechanisms and therapeutic potential: A narrative review. Neurosci Biobehav Rev 2023; 152:105301. [PMID: 37414376 DOI: 10.1016/j.neubiorev.2023.105301] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/26/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023]
Abstract
Potassium channels (K+-channels) selectively control the passive flow of potassium ions across biological membranes and thereby also regulate membrane excitability. Genetic variants affecting many of the human K+-channels are well known causes of Mendelian disorders within cardiology, neurology, and endocrinology. K+-channels are also primary targets of many natural toxins from poisonous organisms and drugs used within cardiology and metabolism. As genetic tools are improving and larger clinical samples are being investigated, the spectrum of clinical phenotypes implicated in K+-channels dysfunction is rapidly expanding, notably within immunology, neurosciences, and metabolism. K+-channels that previously were considered to be expressed in only a few organs and to have discrete physiological functions, have recently been found in multiple tissues and with new, unexpected functions. The pleiotropic functions and patterns of expression of K+-channels may provide additional therapeutic opportunities, along with new emerging challenges from off-target effects. Here we review the functions and therapeutic potential of K+-channels, with an emphasis on the nervous system, roles in neuropsychiatric disorders and their involvement in other organ systems and diseases.
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Affiliation(s)
| | - Pernille Svalastoga
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway; Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | | | - Jeffrey Colm Glennon
- Conway Institute for Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland.
| | - Jan Haavik
- Department of Biomedicine, University of Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Norway.
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Zhang LM, Chen L, Zhao YF, Duan WM, Zhong LM, Liu MW. Identification of key potassium channel genes of temporal lobe epilepsy by bioinformatics analyses and experimental verification. Front Neurol 2023; 14:1175007. [PMID: 37483435 PMCID: PMC10361730 DOI: 10.3389/fneur.2023.1175007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/16/2023] [Indexed: 07/25/2023] Open
Abstract
One of the most prevalent types of epilepsy is temporal lobe epilepsy (TLE), which has unknown etiological factors and drug resistance. The detailed mechanisms underlying potassium channels in human TLE have not yet been elucidated. Hence, this study aimed to mine potassium channel genes linked to TLE using a bioinformatic approach. The results found that Four key TLE-related potassium channel genes (TERKPCGs) were identified: potassium voltage-gated channel subfamily E member (KCNA) 1, KCNA2, potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11), and KCNS1. A protein-protein interaction (PPI) network was constructed to analyze the relationship between TERKPCGs and other key module genes. The results of gene set enrichment analysis (GSEA) for a single gene indicated that the four TERKPCGs were highly linked to the cation channel, potassium channel, respiratory chain, and oxidative phosphorylation. The mRNA-TF network was established using four mRNAs and 113 predicted transcription factors. A ceRNA network containing seven miRNAs, two mRNAs, and 244 lncRNAs was constructed based on the TERKPCGs. Three common small-molecule drugs (enflurane, promethazine, and miconazole) target KCNA1, KCNA2, and KCNS1. Ten small-molecule drugs (glimepiride, diazoxide, levosimendan, and thiamylal et al.) were retrieved for KCNJ11. Compared to normal mice, the expression of KCNA1, KCNA2, KCNJ11, and KCNS1 was downregulated in the brain tissue of the epilepsy mouse model at both the transcriptional and translational levels, which was consistent with the trend of human data from the public database. The results indicated that key potassium channel genes linked to TLE were identified based on bioinformatics analysis to investigate the potential significance of potassium channel genes in the development and treatment of TLE.
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Affiliation(s)
- Lin-ming Zhang
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Ling Chen
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Yi-fei Zhao
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Wei-mei Duan
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Lian-mei Zhong
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, China
| | - Ming-wei Liu
- Department of Emergency, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
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7
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Ashcroft FM. KATP Channels and the Metabolic Regulation of Insulin Secretion in Health and Disease: The 2022 Banting Medal for Scientific Achievement Award Lecture. Diabetes 2023; 72:693-702. [PMID: 37815796 PMCID: PMC10202764 DOI: 10.2337/dbi22-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/28/2023] [Indexed: 10/11/2023]
Abstract
Diabetes is characterized by elevation of plasma glucose due to an insufficiency of the hormone insulin and is associated with both inadequate insulin secretion and impaired insulin action. The Banting Medal for Scientific Achievement Commemorates the work of Sir Frederick Banting, a member of the team that first used insulin to treat a patient with diabetes almost exactly one hundred years ago on 11 January 1922. This article is based on my Banting lecture of 2022 and concerns the mechanism of glucose-stimulated insulin secretion from pancreatic β-cells, with an emphasis on the metabolic regulation of the KATP channel. This channel plays a central role in insulin release. Its closure in response to metabolically generated changes in the intracellular concentrations of ATP and MgADP stimulates β-cell electrical activity and insulin granule exocytosis. Activating mutations in KATP channel genes that impair the ability of the channel to respond to ATP give rise to neonatal diabetes. Impaired KATP channel regulation may also play a role in type 2 diabetes. I conjecture that KATP channel closure in response to glucose is reduced because of impaired glucose metabolism, which fails to generate a sufficient increase in ATP. Consequently, glucose-stimulated β-cell electrical activity is less. As ATP is also required for insulin granule exocytosis, both reduced exocytosis and less β-cell electrical activity may contribute to the reduction in insulin secretion. I emphasize that what follows is not a definitive review of the topic but a personal account of the contribution of my team to the field that is based on my Banting lecture.
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Affiliation(s)
- Frances M. Ashcroft
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, U.K
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Wu B, Xu W. Case report: Neonatal diabetes mellitus caused by KCNJ11 mutation presenting with intracranial hemorrhage. Front Neurol 2023; 14:1072078. [PMID: 36937531 PMCID: PMC10022729 DOI: 10.3389/fneur.2023.1072078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
Neonatal diabetes mellitus (NDM) is a rare type of monogenic diabetes. At present, most published studies have focused on the types of gene mutations associated with NDM and the therapeutic effect of sulfonylureas (SUs) on the disease; few studies on NDM-associated intracranial hemorrhage (ICH) exist. In addition, p.V59M mutations generally lead to intermediate DEND (iDEND: intermediate developmental delay and neonatal diabetes) syndrome without epilepsy. Here, we present a case of a 1-month-old male infant who was diagnosed with NDM caused by a KCNJ11 missense mutation (p.V59M), presenting with cerebral injury. In the early stage of the disease, continuous insulin dose adjustment did not achieve an ideal level of blood glucose. Although blood glucose was subsequently controlled by oral SUs, which were administered after the genetic test result, the patient still displayed epilepsy and developmental delay. In this case report, we present our experience in the treatment of the infant, switching from insulin to oral SUs and we thought that SUs have limited effects on improving the prognosis of neurodevelopmental disturbances in NDM with foci of encephalomalacia. In addition, there may be a relationship between KCNJ11 missense mutations and cerebral injury, and further research must be carried out to confirm these points.
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Jogini V, Jensen MØ, Shaw DE. Gating and modulation of an inward-rectifier potassium channel. J Gen Physiol 2022; 155:213765. [PMID: 36524993 PMCID: PMC9764021 DOI: 10.1085/jgp.202213085] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Inward-rectifier potassium channels (Kirs) are lipid-gated ion channels that differ from other K+ channels in that they allow K+ ions to flow more easily into, rather than out of, the cell. Inward rectification is known to result from endogenous magnesium ions or polyamines (e.g., spermine) binding to Kirs, resulting in a block of outward potassium currents, but questions remain regarding the structural and dynamic basis of the rectification process and lipid-dependent channel activation. Here, we present the results of long-timescale molecular dynamics simulations starting from a crystal structure of phosphatidylinositol 4,5-bisphosphate (PIP2)-bound chicken Kir2.2 with a non-conducting pore. After introducing a mutation (G178R) that is known to increase the open probability of a homologous channel, we were able to observe transitions to a stably open, ion-conducting pore, during which key conformational changes occurred in the main activation gate and the cytoplasmic domain. PIP2 binding appeared to increase stability of the pore in its open and conducting state, as PIP2 removal resulted in pore closure, with a median closure time about half of that with PIP2 present. To investigate structural details of inward rectification, we simulated spermine binding to and unbinding from the open pore conformation at positive and negative voltages, respectively, and identified a spermine-binding site located near a previously hypothesized site between the pore cavity and the selectivity filter. We also studied the effects of long-range electrostatics on conduction and spermine binding by mutating charged residues in the cytoplasmic domain and found that a finely tuned charge density, arising from basic and acidic residues within the cytoplasmic domain, modulated conduction and rectification.
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Affiliation(s)
| | | | - David E. Shaw
- D. E. Shaw Research, New York, NY, USA,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
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Greeley SAW, Polak M, Njølstad PR, Barbetti F, Williams R, Castano L, Raile K, Chi DV, Habeb A, Hattersley AT, Codner E. ISPAD Clinical Practice Consensus Guidelines 2022: The diagnosis and management of monogenic diabetes in children and adolescents. Pediatr Diabetes 2022; 23:1188-1211. [PMID: 36537518 PMCID: PMC10107883 DOI: 10.1111/pedi.13426] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 12/24/2022] Open
Affiliation(s)
- Siri Atma W. Greeley
- Section of Pediatric and Adult Endocrinology, Diabetes and Metabolism, Kovler Diabetes Center and Comer Children's HospitalUniversity of Chicago MedicineChicagoIllinoisUSA
| | - Michel Polak
- Hôpital Universitaire Necker‐Enfants MaladesUniversité de Paris Cité, INSERM U1016, Institut IMAGINEParisFrance
| | - Pål R. Njølstad
- Department of Clinical ScienceUniversity of Bergen, and Children and Youth Clinic, Hauk eland University HospitalBergenNorway
| | - Fabrizio Barbetti
- Clinical Laboratory UnitBambino Gesù Children's Hospital, IRCCSRomeItaly
| | - Rachel Williams
- National Severe Insulin Resistance ServiceCambridge University Hospitals NHS TrustCambridgeUK
| | - Luis Castano
- Endocrinology and Diabetes Research Group, Biocruces Bizkaia Health Research InstituteCruces University Hospital, CIBERDEM, CIBERER, Endo‐ERN, UPV/EHUBarakaldoSpain
| | - Klemens Raile
- Department of Paediatric Endocrinology and DiabetologyCharité – UniversitätsmedizinBerlinGermany
| | - Dung Vu Chi
- Center for Endocrinology, Metabolism, Genetics and Molecular Therapy, Departement of Pediatric Endocrinology and DiabetesVietnam National Children's HospitalHanoiVietnam
- Department of Pediatrics and Department of Biology and Medical GeneticsHanoi Medical UniversityHanoiVietnam
| | - Abdelhadi Habeb
- Department of PediatricsPrince Mohamed bin Abdulaziz Hopsital, National Guard Health AffairsMadinahSaudi Arabia
| | - Andrew T. Hattersley
- Institute of Biomedical and Clinical SciencesUniversity of Exeter Medical SchoolExeterUK
| | - Ethel Codner
- Institute of Maternal and Child ResearchSchool of Medicine, University of ChileSantiagoChile
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de Gouveia Buff Passone C, Giani E, Vaivre-Douret L, Kariyawasam D, Berdugo M, Garcin L, Beltrand J, Bernardo WM, Polak M. Sulfonylurea for improving neurological features in neonatal diabetes: A systematic review and meta-analyses. Pediatr Diabetes 2022; 23:675-692. [PMID: 35657808 DOI: 10.1111/pedi.13376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/19/2022] [Accepted: 05/31/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE In monogenic diabetes due to KCNJ11 and ABCC8 mutations that impair KATP- channel function, sulfonylureas improve long-term glycemic control. Although KATP channels are extensively expressed in the brain, the effect of sulfonylureas on neurological function has varied widely. We evaluated published evidence about potential effects of sulfonylureas on neurological features, especially epilepsy, cognition, motor function and muscular tone, visuo-motor integration, and attention deficits in children and adults with KCNJ11 and ABCC8-related neonatal-onset diabetes mellitus. RESEARCH DESIGN AND METHODS We conducted a systematic review and meta-analyses of the literature (PROSPERO, CRD42021254782), including individual-patient data, according to PRISMA, using RevMan software. We also graded the level of evidence. RESULTS We selected 34 of 776 publications. The evaluation of global neurological function before and after sulfonylurea (glibenclamide) treatment in 114 patients yielded a risk difference (RD) of 58% (95%CI, 43%-74%; I2 = 54%) overall and 73% (95%CI, 32%-113%; I2 = 0%) in the subgroup younger than 4 years; the level of evidence was moderate and high, respectively. EEG studies of epilepsy showed a RD of 56% (95%CI, 23%-89%; I2 = 34%) in patients with KCNJ11 mutations, with a high quality of evidence. For hypotonia and motor function, the RDs were 90% (95%CI, 69%-111%; I2 = 0%) and 73% (95%CI, 35%-111%; I2 = 0%), respectively, with a high level of evidence. CONCLUSIONS Glibenclamide significantly improved neurological abnormalities in patients with neonatal-onset diabetes due to KCNJ11 or ABCC8 mutations. Hypotonia was the symptom that responded best. Earlier treatment initiation was associated with greater benefits.
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Affiliation(s)
- Caroline de Gouveia Buff Passone
- Pediatric Endocrinology, Gynaecology and Diabetology, Centre de Référence des Pathologies Gynécologiques Rares et des Maladies Endocriniennes Rares de la Croissance et du Développement, Hôpital Universitaire Necker Enfants Malades, Université de Paris, Paris, France.,Department of Endocrinology, Metabolism and Diabetes, Inserm U1016, Cochin Institute, Paris, France.,Pediatric Endocrinology Department, University of Sao Paulo, Sao Paulo, Brazil
| | - Elisa Giani
- Pediatric Endocrinology, Gynaecology and Diabetology, Centre de Référence des Pathologies Gynécologiques Rares et des Maladies Endocriniennes Rares de la Croissance et du Développement, Hôpital Universitaire Necker Enfants Malades, Université de Paris, Paris, France.,Department of Endocrinology, Metabolism and Diabetes, Inserm U1016, Cochin Institute, Paris, France.,Department of Biomedical Sciences, Humanitas University, Milan, Italy
| | - Laurence Vaivre-Douret
- Faculty of Health, Department of Medicine Paris Descartes, Université de Paris, and Institut Universitaire de France (IUF), Paris, France.,National Institute of Health and Medical Research (INSERM UMR 1018-CESP), Faculty of Medicine, University of Paris-Saclay, UVSQ, Villejuif, France.,Imagine Institute, Paris, France
| | - Dulanjalee Kariyawasam
- Pediatric Endocrinology, Gynaecology and Diabetology, Centre de Référence des Pathologies Gynécologiques Rares et des Maladies Endocriniennes Rares de la Croissance et du Développement, Hôpital Universitaire Necker Enfants Malades, Université de Paris, Paris, France.,Imagine Institute, Paris, France
| | - Marianne Berdugo
- Physiopathology of Ocular Diseases: Therapeutic Innovations, Sorbonne-Université and Université de Paris, Inserm UMRS 1138, Paris, France
| | - Laure Garcin
- Pediatric Endocrinology, Gynaecology and Diabetology, Centre de Référence des Pathologies Gynécologiques Rares et des Maladies Endocriniennes Rares de la Croissance et du Développement, Hôpital Universitaire Necker Enfants Malades, Université de Paris, Paris, France
| | - Jacques Beltrand
- Pediatric Endocrinology, Gynaecology and Diabetology, Centre de Référence des Pathologies Gynécologiques Rares et des Maladies Endocriniennes Rares de la Croissance et du Développement, Hôpital Universitaire Necker Enfants Malades, Université de Paris, Paris, France.,Department of Endocrinology, Metabolism and Diabetes, Inserm U1016, Cochin Institute, Paris, France.,Imagine Institute, Paris, France
| | | | - Michel Polak
- Pediatric Endocrinology, Gynaecology and Diabetology, Centre de Référence des Pathologies Gynécologiques Rares et des Maladies Endocriniennes Rares de la Croissance et du Développement, Hôpital Universitaire Necker Enfants Malades, Université de Paris, Paris, France.,Department of Endocrinology, Metabolism and Diabetes, Inserm U1016, Cochin Institute, Paris, France.,Imagine Institute, Paris, France
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12
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Yang HQ, Echeverry FA, ElSheikh A, Gando I, Anez Arredondo S, Samper N, Cardozo T, Delmar M, Shyng SL, Coetzee WA. Subcellular trafficking and endocytic recycling of K ATP channels. Am J Physiol Cell Physiol 2022; 322:C1230-C1247. [PMID: 35508187 PMCID: PMC9169827 DOI: 10.1152/ajpcell.00099.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 11/22/2022]
Abstract
Sarcolemmal/plasmalemmal ATP-sensitive K+ (KATP) channels have key roles in many cell types and tissues. Hundreds of studies have described how the KATP channel activity and ATP sensitivity can be regulated by changes in the cellular metabolic state, by receptor signaling pathways and by pharmacological interventions. These alterations in channel activity directly translate to alterations in cell or tissue function, that can range from modulating secretory responses, such as insulin release from pancreatic β-cells or neurotransmitters from neurons, to modulating contractile behavior of smooth muscle or cardiac cells to elicit alterations in blood flow or cardiac contractility. It is increasingly becoming apparent, however, that KATP channels are regulated beyond changes in their activity. Recent studies have highlighted that KATP channel surface expression is a tightly regulated process with similar implications in health and disease. The surface expression of KATP channels is finely balanced by several trafficking steps including synthesis, assembly, anterograde trafficking, membrane anchoring, endocytosis, endocytic recycling, and degradation. This review aims to summarize the physiological and pathophysiological implications of KATP channel trafficking and mechanisms that regulate KATP channel trafficking. A better understanding of this topic has potential to identify new approaches to develop therapeutically useful drugs to treat KATP channel-related diseases.
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Affiliation(s)
- Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | | | - Assmaa ElSheikh
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Ivan Gando
- Department of Pathology, NYU School of Medicine, New York, New York
| | | | - Natalie Samper
- Department of Pathology, NYU School of Medicine, New York, New York
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - Mario Delmar
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
- Department of Medicine, NYU School of Medicine, New York, New York
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - William A Coetzee
- Department of Pathology, NYU School of Medicine, New York, New York
- Department of Neuroscience & Physiology, NYU School of Medicine, New York, New York
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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13
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Ramu Y, Yamakaze J, Zhou Y, Hoshi T, Lu Z. Blocking Kir6.2 channels with SpTx1 potentiates glucose-stimulated insulin secretion from murine pancreatic β cells and lowers blood glucose in diabetic mice. eLife 2022; 11:77026. [PMID: 35212627 PMCID: PMC8880991 DOI: 10.7554/elife.77026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 01/26/2022] [Indexed: 11/16/2022] Open
Abstract
ATP-sensitive K+ (KATP) channels in pancreatic β cells are comprised of pore-forming subunits (Kir6.2) and modulatory sulfonylurea receptor subunits (SUR1). The ATP sensitivity of these channels enables them to couple metabolic state to insulin secretion in β cells. Antidiabetic sulfonylureas such as glibenclamide target SUR1 and indirectly suppress Kir6.2 activity. Glibenclamide acts as both a primary and a secondary secretagogue to trigger insulin secretion and potentiate glucose-stimulated insulin secretion, respectively. We tested whether blocking Kir6.2 itself causes the same effects as glibenclamide, and found that the Kir6.2 pore-blocking venom toxin SpTx1 acts as a strong secondary, but not a strong primary, secretagogue. SpTx1 triggered a transient rise of plasma insulin and lowered the elevated blood glucose of diabetic mice overexpressing Kir6.2 but did not affect those of nondiabetic mice. This proof-of-concept study suggests that blocking Kir6.2 may serve as an effective treatment for diabetes and other diseases stemming from KATP hyperactivity that cannot be adequately suppressed with sulfonylureas.
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Affiliation(s)
- Yajamana Ramu
- Department of Physiology, Perelman School of Medicine University of Pennsylvania, Philadelphia, United States
| | - Jayden Yamakaze
- Department of Physiology, Perelman School of Medicine University of Pennsylvania, Philadelphia, United States
| | - Yufeng Zhou
- Department of Physiology, Perelman School of Medicine University of Pennsylvania, Philadelphia, United States
| | - Toshinori Hoshi
- Department of Physiology, Perelman School of Medicine University of Pennsylvania, Philadelphia, United States
| | - Zhe Lu
- Department of Physiology, Perelman School of Medicine University of Pennsylvania, Philadelphia, United States
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14
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Houtman MJC, Friesacher T, Chen X, Zangerl-Plessl EM, van der Heyden MAG, Stary-Weinzinger A. Development of I KATP Ion Channel Blockers Targeting Sulfonylurea Resistant Mutant K IR6.2 Based Channels for Treating DEND Syndrome. Front Pharmacol 2022; 12:814066. [PMID: 35095528 PMCID: PMC8795863 DOI: 10.3389/fphar.2021.814066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: DEND syndrome is a rare channelopathy characterized by a combination of developmental delay, epilepsy and severe neonatal diabetes. Gain of function mutations in the KCNJ11 gene, encoding the KIR6.2 subunit of the IKATP potassium channel, stand at the basis of most forms of DEND syndrome. In a previous search for existing drugs with the potential of targeting Cantú Syndrome, also resulting from increased IKATP, we found a set of candidate drugs that may also possess the potential to target DEND syndrome. In the current work, we combined Molecular Modelling including Molecular Dynamics simulations, with single cell patch clamp electrophysiology, in order to test the effect of selected drug candidates on the KIR6.2 WT and DEND mutant channels. Methods: Molecular dynamics simulations were performed to investigate potential drug binding sites. To conduct in vitro studies, KIR6.2 Q52R and L164P mutants were constructed. Inside/out patch clamp electrophysiology on transiently transfected HEK293T cells was performed for establishing drug-channel inhibition relationships. Results: Molecular Dynamics simulations provided insight in potential channel interaction and shed light on possible mechanisms of action of the tested drug candidates. Effective IKIR6.2/SUR2a inhibition was obtained with the pore-blocker betaxolol (IC50 values 27-37 μM). Levobetaxolol effectively inhibited WT and L164P (IC50 values 22 μM) and Q52R (IC50 55 μM) channels. Of the SUR binding prostaglandin series, travoprost was found to be the best blocker of WT and L164P channels (IC50 2-3 μM), while Q52R inhibition was 15-20% at 10 μM. Conclusion: Our combination of MD and inside-out electrophysiology provides the rationale for drug mediated IKATP inhibition, and will be the basis for 1) screening of additional existing drugs for repurposing to address DEND syndrome, and 2) rationalized medicinal chemistry to improve IKATP inhibitor efficacy and specificity.
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Affiliation(s)
- Marien J C Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Theres Friesacher
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Xingyu Chen
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Eva-Maria Zangerl-Plessl
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Anna Stary-Weinzinger
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
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15
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Shyng SL. K ATP Channel Function: More than Meets the Eye. FUNCTION (OXFORD, ENGLAND) 2022; 3:zqab070. [PMID: 35059642 PMCID: PMC8759536 DOI: 10.1093/function/zqab070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 01/07/2023]
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16
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Luo Y, Wang T, Chen Z, Zhang G. Knowledge domain and emerging trends in beta-cell research: A bibliometric and knowledge-map analysis. Front Endocrinol (Lausanne) 2022; 13:1086667. [PMID: 36743933 PMCID: PMC9892706 DOI: 10.3389/fendo.2022.1086667] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/30/2022] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Up to now, the physiology, pathology, and recovery of beta-cells have been intensively studied and made great progress, and these are of major significance for the treatment of related diseases. Nevertheless, a comprehensive and objective report on the status of beta-cell research is lacking. Therefore, this study aims to conduct a bibliometric analysis to quantify and identify the current status and trending issues in beta-cell research. METHODS The articles and reviews related to beta-cell were obtained from the Web of Science Core Collection on August 31, 2022. Two scientometric software (CiteSpace 6.1.R3 and VOSviewer 1.6.18) were used to perform bibliometric and knowledge-map analysis. RESULTS A total of 4098 papers were published in 810 academic journals in 2938 institutions from 83 countries/regions. The number of beta-cell-related publications was increasing steadily. The United States was the most productive country, while Universite libre de Bruxelles, University of Toronto and University of Geneva were the most active institutions. Diabetes published the most beta-cell studies and received the largest number of co-citations. Decio I Eizirik published the most papers and had the most co-citations. Twelve references on reviews and mechanisms were regarded as the knowledge base. Four major aspects of beta-cell research included the pathological mechanism of beta-cell failure, the recovery of beta cells, the risk factor related to beta cells, and the physiology of beta cells. Endoplasmic reticulum stress and oxidative stress have been core elements throughout the research in this field. In addition, beta-cell dedifferentiation, inflammation, autophagy, miRNA, and lncRNA are hot topics nowadays. Additionally, stem cell replacement therapies might be the alternative way to reverse beta-cell failure. Restoring beta-cell mass and function will remain a research goal in the future. CONCLUSION This study provided a comprehensive overview of beta-cell research through bibliometric and visual methods. The information would provide helpful references for scholars focusing on beta cells.
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Affiliation(s)
- Yunpeng Luo
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
- Institute of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Tong Wang
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Zhuhong Chen
- Institute of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Guangde Zhang, ; Zhuhong Chen,
| | - Guangde Zhang
- Institute of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Guangde Zhang, ; Zhuhong Chen,
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17
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Coyote-Maestas W, Nedrud D, He Y, Schmidt D. Determinants of trafficking, conduction, and disease within a K + channel revealed through multiparametric deep mutational scanning. eLife 2022; 11:76903. [PMID: 35639599 PMCID: PMC9273215 DOI: 10.7554/elife.76903] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 05/27/2022] [Indexed: 01/04/2023] Open
Abstract
A long-standing goal in protein science and clinical genetics is to develop quantitative models of sequence, structure, and function relationships to understand how mutations cause disease. Deep mutational scanning (DMS) is a promising strategy to map how amino acids contribute to protein structure and function and to advance clinical variant interpretation. Here, we introduce 7429 single-residue missense mutations into the inward rectifier K+ channel Kir2.1 and determine how this affects folding, assembly, and trafficking, as well as regulation by allosteric ligands and ion conduction. Our data provide high-resolution information on a cotranslationally folded biogenic unit, trafficking and quality control signals, and segregated roles of different structural elements in fold stability and function. We show that Kir2.1 surface trafficking mutants are underrepresented in variant effect databases, which has implications for clinical practice. By comparing fitness scores with expert-reviewed variant effects, we can predict the pathogenicity of 'variants of unknown significance' and disease mechanisms of known pathogenic mutations. Our study in Kir2.1 provides a blueprint for how multiparametric DMS can help us understand the mechanistic basis of genetic disorders and the structure-function relationships of proteins.
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Affiliation(s)
- Willow Coyote-Maestas
- Department of Biochemistry, Molecular Biology and Biophysics, University of MinnesotaMinneapolisUnited States
| | - David Nedrud
- Department of Biochemistry, Molecular Biology and Biophysics, University of MinnesotaMinneapolisUnited States
| | - Yungui He
- Department of Genetics, Cell Biology and Development, University of MinnesotaMinneapolisUnited States
| | - Daniel Schmidt
- Department of Genetics, Cell Biology and Development, University of MinnesotaMinneapolisUnited States
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18
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Fagnen C, Bannwarth L, Oubella I, Zuniga D, Haouz A, Forest E, Scala R, Bendahhou S, De Zorzi R, Perahia D, Vénien-Bryan C. Integrative Study of the Structural and Dynamical Properties of a KirBac3.1 Mutant: Functional Implication of a Highly Conserved Tryptophan in the Transmembrane Domain. Int J Mol Sci 2021; 23:335. [PMID: 35008764 PMCID: PMC8745282 DOI: 10.3390/ijms23010335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/18/2021] [Accepted: 12/23/2021] [Indexed: 12/02/2022] Open
Abstract
ATP-sensitive potassium (K-ATP) channels are ubiquitously expressed on the plasma membrane of cells in several organs, including the heart, pancreas, and brain, and they govern a wide range of physiological processes. In pancreatic β-cells, K-ATP channels composed of Kir6.2 and SUR1 play a key role in coupling blood glucose and insulin secretion. A tryptophan residue located at the cytosolic end of the transmembrane helix is highly conserved in eukaryote and prokaryote Kir channels. Any mutation on this amino acid causes a gain of function and neonatal diabetes mellitus. In this study, we have investigated the effect of mutation on this highly conserved residue on a KirBac channel (prokaryotic homolog of mammalian Kir6.2). We provide the crystal structure of the mutant KirBac3.1 W46R (equivalent to W68R in Kir6.2) and its conformational flexibility properties using HDX-MS. In addition, the detailed dynamical view of the mutant during the gating was investigated using the in silico method. Finally, functional assays have been performed. A comparison of important structural determinants for the gating mechanism between the wild type KirBac and the mutant W46R suggests interesting structural and dynamical clues and a mechanism of action of the mutation that leads to the gain of function.
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Affiliation(s)
- Charline Fagnen
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, 4 Ave. des Sciences, 91190 Gif-sur-Yvette, France;
| | - Ludovic Bannwarth
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
| | - Iman Oubella
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
| | - Dania Zuniga
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
| | - Ahmed Haouz
- Institut Pasteur, C2RT-Plate-Forme de Cristallographie CNRS-UMR3528, 75724 Paris, France;
| | - Eric Forest
- CNRS, IBS, CEA, University Grenoble Alpes, 38044 Grenoble, France;
| | - Rosa Scala
- CNRS UMR7370, LP2M, Labex ICST, Faculté de Médecine, University Côte d’Azur, 06560 Nice, France; (R.S.); (S.B.)
| | - Saïd Bendahhou
- CNRS UMR7370, LP2M, Labex ICST, Faculté de Médecine, University Côte d’Azur, 06560 Nice, France; (R.S.); (S.B.)
| | - Rita De Zorzi
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Licio Giorgeri 1, 34127 Trieste, Italy;
| | - David Perahia
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole Normale Supérieure Paris-Saclay, 4 Ave. des Sciences, 91190 Gif-sur-Yvette, France;
| | - Catherine Vénien-Bryan
- IMPMC, UMR 7590, CNRS, Muséum National d’Histoire Naturelle, Sorbonne Université, 75005 Paris, France; (C.F.); (L.B.); (I.O.); (D.Z.)
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19
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Barash G, Bassan H, Livne A, Benyamini L, Heyman E, Bowman P, Rachmiel M. Novel perspectives of super-high dose sulfonylurea and high-dose oral prednisolone in an infant with DEND syndrome due to V64M heterozygote KCNJ11 mutation. Acta Diabetol 2021; 58:1665-1672. [PMID: 34272607 DOI: 10.1007/s00592-021-01763-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 06/11/2021] [Indexed: 12/25/2022]
Abstract
AIMS To report a novel mutation associated with developmental delay, epilepsy, and neonatal diabetes-DEND Syndrome, responsive to a novel management combination. METHODS We describe the investigation, treatment, and genetic diagnosis of a newborn diagnosed with DEND syndrome. RESULTS The patient was found to be de-novo heterozygous for pathogenic KCNJ11 missense variant: c.190G > A, p. (Val64Met), associated with DEND syndrome, responsive to a combination of super high doses of sulfonylurea (SU) and oral high-dose steroids. A single case was reported so far due to this mutation, presenting with severe DEND syndrome, treated by insulin only. His phenotypic description and management during 18 months, demonstrates this mutation is responsive to super-high doses of SU combined with high dose 6 weeks steroids protocol. CONCLUSIONS We have identified a heterozygous missense mutation as the etiology for severe DEND syndrome in a one-day old neonate, presenting with asymptomatic hyperglycemia, responsive to a novel management combination.
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Affiliation(s)
- Galia Barash
- Pediatric Endocrinology and Diabetes Institute Shamir Medical Center, 70300, Zerifin, Israel
| | - Haim Bassan
- Pediatric Neurology and Development Center Shamir Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ayelet Livne
- Neonatal Intensive Care Unit Shamir Medical Center, Tel Aviv, Israel
| | | | - Eli Heyman
- Pediatric Neurology and Development Center Shamir Medical Center, Tel Aviv, Israel
| | | | - Marianna Rachmiel
- Pediatric Endocrinology and Diabetes Institute Shamir Medical Center, 70300, Zerifin, Israel.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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20
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Dalgin G, Tryba AK, Cohen AP, Park SY, Philipson LH, Greeley SAW, Garcia AJ. Developmental defects and impaired network excitability in a cerebral organoid model of KCNJ11 p.V59M-related neonatal diabetes. Sci Rep 2021; 11:21590. [PMID: 34732776 PMCID: PMC8566525 DOI: 10.1038/s41598-021-00939-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 10/14/2021] [Indexed: 11/09/2022] Open
Abstract
The gene KCNJ11 encodes Kir6.2 a major subunit of the ATP-sensitive potassium channel (KATP) expressed in both the pancreas and brain. Heterozygous gain of function mutations in KCNJ11 can cause neonatal diabetes mellitus (NDM). In addition, many patients exhibit neurological defects ranging from modest learning disorders to severe cognitive dysfunction and seizures. However, it remains unclear to what extent these neurological deficits are due to direct brain-specific activity of mutant KATP. We have generated cerebral organoids derived from human induced pluripotent stem cells (hiPSCs) possessing the KCNJ11 mutation p.Val59Met (V59M) and from non-pathogenic/normal hiPSCs (i.e., control/WT). Control cerebral organoids developed neural networks that could generate stable synchronized bursting neuronal activity whereas those derived from V59M cerebral organoids showed reduced synchronization. Histocytochemical studies revealed a marked reduction in neurons localized to upper cortical layer-like structures in V59M cerebral organoids suggesting dysfunction in the development of cortical neuronal network. Examination of temporal transcriptional profiles of neural stem cell markers revealed an extended window of SOX2 expression in V59M cerebral organoids. Continuous treatment of V59M cerebral organoids with the KATP blocker tolbutamide partially rescued the neurodevelopmental differences. Our study demonstrates the utility of human cerebral organoids as an investigative platform for studying the effects of KCNJ11 mutations on neurophysiological outcome.
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Affiliation(s)
- Gokhan Dalgin
- Section of Endocrinology, Diabetes and Metabolism, Departments of Medicine and Pediatrics, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA.
| | - Andrew K Tryba
- Section of Pediatric Neurology, Department of Pediatrics, The University of Chicago, Chicago, IL, USA
| | - Ashley P Cohen
- Chicago Medical School, Rosalind Franklin University, North Chicago, IL, USA
| | - Soo-Young Park
- Section of Endocrinology, Diabetes and Metabolism, Departments of Medicine and Pediatrics, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA
| | - Louis H Philipson
- Section of Endocrinology, Diabetes and Metabolism, Departments of Medicine and Pediatrics, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA
| | - Siri Atma W Greeley
- Section of Endocrinology, Diabetes and Metabolism, Departments of Medicine and Pediatrics, Kovler Diabetes Center, The University of Chicago, Chicago, IL, USA
| | - Alfredo J Garcia
- Section of Emergency Medicine, Department of Medicine, Institute for Integrative Physiology, Grossman Institute for Neuroscience, The University of Chicago, Chicago, USA.
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21
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Tong X, Stein R. Lipid Droplets Protect Human β-Cells From Lipotoxicity-Induced Stress and Cell Identity Changes. Diabetes 2021; 70:2595-2607. [PMID: 34433630 PMCID: PMC8564404 DOI: 10.2337/db21-0261] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022]
Abstract
Free fatty acids (FFAs) are often stored in lipid droplet (LD) depots for eventual metabolic and/or synthetic use in many cell types, such a muscle, liver, and fat. In pancreatic islets, overt LD accumulation was detected in humans but not mice. LD buildup in islets was principally observed after roughly 11 years of age, increasing throughout adulthood under physiologic conditions, and also enriched in type 2 diabetes. To obtain insight into the role of LDs in human islet β-cell function, the levels of a key LD scaffold protein, perilipin 2 (PLIN2), were manipulated by lentiviral-mediated knockdown (KD) or overexpression (OE) in EndoCβH2-Cre cells, a human cell line with adult islet β-like properties. Glucose-stimulated insulin secretion was blunted in PLIN2KD cells and improved in PLIN2OE cells. An unbiased transcriptomic analysis revealed that limiting LD formation induced effectors of endoplasmic reticulum (ER) stress that compromised the expression of critical β-cell function and identity genes. These changes were essentially reversed by PLIN2OE or using the ER stress inhibitor, tauroursodeoxycholic acid. These results strongly suggest that LDs are essential for adult human islet β-cell activity by preserving FFA homeostasis.
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Affiliation(s)
- Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
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22
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Akyuz E, Koklu B, Uner A, Angelopoulou E, Paudel YN. Envisioning the role of inwardly rectifying potassium (Kir) channel in epilepsy. J Neurosci Res 2021; 100:413-443. [PMID: 34713909 DOI: 10.1002/jnr.24985] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 09/23/2021] [Accepted: 10/01/2021] [Indexed: 01/29/2023]
Abstract
Epilepsy is a devastating neurological disorder characterized by recurrent seizures attributed to the disruption of the dynamic excitatory and inhibitory balance in the brain. Epilepsy has emerged as a global health concern affecting about 70 million people worldwide. Despite recent advances in pre-clinical and clinical research, its etiopathogenesis remains obscure, and there are still no treatment strategies modifying disease progression. Although the precise molecular mechanisms underlying epileptogenesis have not been clarified yet, the role of ion channels as regulators of cellular excitability has increasingly gained attention. In this regard, emerging evidence highlights the potential implication of inwardly rectifying potassium (Kir) channels in epileptogenesis. Kir channels consist of seven different subfamilies (Kir1-Kir7), and they are highly expressed in both neuronal and glial cells in the central nervous system. These channels control the cell volume and excitability. In this review, we discuss preclinical and clinical evidence on the role of the several subfamilies of Kir channels in epileptogenesis, aiming to shed more light on the pathogenesis of this disorder and pave the way for future novel therapeutic approaches.
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Affiliation(s)
- Enes Akyuz
- Faculty of International Medicine, Department of Biophysics, University of Health Sciences, Istanbul, Turkey
| | - Betul Koklu
- Faculty of Medicine, Namık Kemal University, Tekirdağ, Turkey
| | - Arda Uner
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Yam Nath Paudel
- Neuropharmacology Research Strength, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Malaysia
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Razzaghy-Azar M, Nourbakhsh M, Talea A, Mohammad Amoli M, Nourbakhsh M, Larijani B. Meglitinide (repaglinide) therapy in permanent neonatal diabetes mellitus: two case reports. J Med Case Rep 2021; 15:535. [PMID: 34696808 PMCID: PMC8543822 DOI: 10.1186/s13256-021-03052-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 08/06/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Permanent neonatal diabetes mellitus (PNDM) presents with dehydration and hyperglycemia, which usually occurs during the first 12 months of life. Activating mutations of beta-cell adenosine triphosphate-sensitive potassium [KATP] channel subunits that cause opening of the channel are associated with PNDM. Some patients with PNDM respond to administration of a sulfonylurea derivative, which has long action on blood glucose even during hypoglycemia and has an apoptotic effect on beta cells. However, there have been no reports regarding treatment with meglitinide (repaglinide), which has rapid and short duration of action during the rise in blood glucose after meals that is more similar to beta cell function. It has no effects during hypoglycemia, so it does not cause neurological damage, and has no apoptotic effect on beta cells. We report herein the effects of repaglinide administration in the management and clinical outcome of two patients with PNDM during 9 and 10 years of follow-up. CASE PRESENTATION Two Iranian infants were brought to our institution with poor general condition, dehydration, lethargy, and poor feeding. They had diabetic ketoacidosis at 52 days and 3.5 months of age, respectively. Their genetic analysis revealed mutations in the KCNJ11 gene encoding KIR6.2, so they both had PNDM. After treatment of diabetic ketoacidosis with insulin, they responded to sulfonylurea (glibenclamide) treatment, but were switched to repaglinide because of blood sugar fluctuations in terms of hyper- and hypoglycemia. Repaglinide was administered with the dosage of 0.04 mg/kg/day divided before every meal. RESULTS The patients were 10 and 9 years old at the last visit, with normal growth parameters. The values of self-monitored blood glucose were well-controlled, and the hemoglobin A1C (HbA1C) levels ranged from 3.6 to 6.4% during the follow-up period. There was no complication of diabetes, neurological disorder, or adverse effects related to repaglinide. CONCLUSION In every neonate or infant < 6 months of age with diabetes mellitus, PNDM should be considered. A trial of oral repaglinide can be performed and substituted for glibenclamide for prevention of hypoglycemia, neurological damage, and apoptosis of beta cells during long-term administration.
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Affiliation(s)
- Maryam Razzaghy-Azar
- Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.,Pediatrics and Pediatric Endocrinology and Metabolism, Hazrat Aliasghar Children's Hospital, Iran University of Medical Sciences, 1449614535, Tehran, Iran
| | - Mitra Nourbakhsh
- Department of Biochemistry, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Talea
- Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Mohammad Amoli
- Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mona Nourbakhsh
- Pediatrics and Pediatric Endocrinology and Metabolism, Hazrat Aliasghar Children's Hospital, Iran University of Medical Sciences, 1449614535, Tehran, Iran.
| | - Bagher Larijani
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
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Yahaya TO, Anyebe DA. Genes predisposing to neonatal diabetes mellitus and pathophysiology: Current findings. J Neonatal Perinatal Med 2021; 13:543-553. [PMID: 32333556 DOI: 10.3233/npm-190353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Precision medicine, described as a therapeutic procedure in which complex diseases are treated based on the causal gene and pathophysiology, is being considered for diabetes mellitus (DM). To this end, several monogenetic mutations in the beta cells have been linked with neonatal diabetes mellitus (NDM), however, the list of suspect genes is expansive, necessitating an update. This study, therefore, provides an update on NDM candidate genes and pathophysiology. RESULTS Reputable online academic databases were searched for relevant information, which led to the identification of 43 genes whose mutations are linked to the condition. Of the linked genes, mutations in the KCNJ11, ABCC8, and INS genes as well as the genes on 6q24 chromosomal region are the most frequently implicated. Mutations in these genes can cause pancreatic agenesis and developmental errors, resulting in NDM in the first six to twelve months of birth. The clinical presentations of NDM include frequent urination, rapid breathing, and dehydration, among others. CONCLUSIONS Monogenetic mutations in the beta cells may cause NDM with distinct pathophysiology from other DM. Treatment options that target NDM candidate genes and pathophysiology may lead to an improved treatment compared with the present generalized treatment for all forms of DM.
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Affiliation(s)
- T O Yahaya
- Department of Biology, Federal University Birnin Kebbi, Nigeria
| | - D A Anyebe
- Department of Biochemistry and Molecular Biology, Federal University Birnin Kebbi, Nigeria
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Tang D, Xu J, Li Y, Zhao P, Kong X, Hu H, Liang S, Tang C, Liu Z. Molecular mechanisms of centipede toxin SsTx-4 inhibition of inwardly rectifying potassium channels. J Biol Chem 2021; 297:101076. [PMID: 34391777 PMCID: PMC8413892 DOI: 10.1016/j.jbc.2021.101076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022] Open
Abstract
Inwardly rectifying potassium channels (Kirs) are important drug targets, with antagonists for the Kir1.1, Kir4.1, and pancreatic Kir6.2/SUR1 channels being potential drug candidates for treating hypertension, depression, and diabetes, respectively. However, few peptide toxins acting on Kirs are identified and their interacting mechanisms remain largely elusive yet. Herein, we showed that the centipede toxin SsTx-4 potently inhibited the Kir1.1, Kir4.1, and Kir6.2/SUR1 channels with nanomolar to submicromolar affinities and intensively studied the molecular bases for toxin–channel interactions using patch-clamp analysis and site-directed mutations. Other Kirs including Kir2.1 to 2.4, Kir4.2, and Kir7.1 were resistant to SsTx-4 treatment. Moreover, SsTx-4 inhibited the inward and outward currents of Kirs with different potencies, possibly caused by a K+ “knock-off” effect, suggesting the toxin functions as an out pore blocker physically occluding the K+-conducting pathway. This conclusion was further supported by a mutation analysis showing that M137 located in the outer vestibule of the Kir6.2/ΔC26 channel was the key residue mediating interaction with SsTx-4. On the other hand, the molecular determinants within SsTx-4 for binding these Kir channels only partially overlapped, with K13 and F44 being the common key residues. Most importantly, K11A, P15A, and Y16A mutant toxins showed improved affinity and/or selectivity toward Kir6.2, while R12A mutant toxin had increased affinity for Kir4.1. To our knowledge, SsTx-4 is the first characterized peptide toxin with Kir4.1 inhibitory activity. This study provides useful insights for engineering a Kir6.2/SUR1 channel–specific antagonist based on the SsTx-4 template molecule and may be useful in developing new antidiabetic drugs.
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Affiliation(s)
- Dongfang Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China; College of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, Hunan, China
| | - Jiahui Xu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yinping Li
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Piao Zhao
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xiangjin Kong
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Haoliang Hu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China.
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China.
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Tuluc P, Theiner T, Jacobo-Piqueras N, Geisler SM. Role of High Voltage-Gated Ca 2+ Channel Subunits in Pancreatic β-Cell Insulin Release. From Structure to Function. Cells 2021; 10:2004. [PMID: 34440773 PMCID: PMC8393260 DOI: 10.3390/cells10082004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/27/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023] Open
Abstract
The pancreatic islets of Langerhans secrete several hormones critical for glucose homeostasis. The β-cells, the major cellular component of the pancreatic islets, secrete insulin, the only hormone capable of lowering the plasma glucose concentration. The counter-regulatory hormone glucagon is secreted by the α-cells while δ-cells secrete somatostatin that via paracrine mechanisms regulates the α- and β-cell activity. These three peptide hormones are packed into secretory granules that are released through exocytosis following a local increase in intracellular Ca2+ concentration. The high voltage-gated Ca2+ channels (HVCCs) occupy a central role in pancreatic hormone release both as a source of Ca2+ required for excitation-secretion coupling as well as a scaffold for the release machinery. HVCCs are multi-protein complexes composed of the main pore-forming transmembrane α1 and the auxiliary intracellular β, extracellular α2δ, and transmembrane γ subunits. Here, we review the current understanding regarding the role of all HVCC subunits expressed in pancreatic β-cell on electrical activity, excitation-secretion coupling, and β-cell mass. The evidence we review was obtained from many seminal studies employing pharmacological approaches as well as genetically modified mouse models. The significance for diabetes in humans is discussed in the context of genetic variations in the genes encoding for the HVCC subunits.
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Affiliation(s)
- Petronel Tuluc
- Centre for Molecular Biosciences, Department of Pharmacology and Toxicology, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria; (T.T.); (N.J.-P.); (S.M.G.)
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Cordiner RLM, Mari A, Tura A, Pearson ER. The Impact of Low-dose Gliclazide on the Incretin Effect and Indices of Beta-cell Function. J Clin Endocrinol Metab 2021; 106:2036-2046. [PMID: 33693776 PMCID: PMC8692237 DOI: 10.1210/clinem/dgab151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Indexed: 12/02/2022]
Abstract
AIMS/HYPOTHESIS Studies in permanent neonatal diabetes suggest that sulphonylureas lower blood glucose without causing hypoglycemia, in part by augmenting the incretin effect. This mechanism has not previously been attributed to sulphonylureas in patients with type 2 diabetes (T2DM). We therefore aimed to evaluate the impact of low-dose gliclazide on beta-cell function and incretin action in patients with T2DM. METHODS Paired oral glucose tolerance tests and isoglycemic infusions were performed to evaluate the difference in the classical incretin effect in the presence and absence of low-dose gliclazide in 16 subjects with T2DM (hemoglobin A1c < 64 mmol/mol, 8.0%) treated with diet or metformin monotherapy. Beta-cell function modeling was undertaken to describe the relationship between insulin secretion and glucose concentration. RESULTS A single dose of 20 mg gliclazide reduced mean glucose during the oral glucose tolerance test from 12.01 ± 0.56 to 10.82 ± 0.5mmol/l [P = 0.0006; mean ± standard error of the mean (SEM)]. The classical incretin effect was augmented by 20 mg gliclazide, from 35.5% (lower quartile 27.3, upper quartile 61.2) to 54.99% (34.8, 72.8; P = 0.049). Gliclazide increased beta-cell glucose sensitivity by 46% [control 22.61 ± 3.94, gliclazide 33.11 ± 7.83 (P = 0.01)] as well as late-phase incretin potentiation [control 0.92 ± 0.05, gliclazide 1.285 ± 0.14 (P = 0.038)]. CONCLUSIONS/INTERPRETATION Low-dose gliclazide reduces plasma glucose in response to oral glucose load, with concomitant augmentation of the classical incretin effect. Beta-cell modeling shows that low plasma concentrations of gliclazide potentiate late-phase insulin secretion and increase glucose sensitivity by 50%. Further studies are merited to explore whether low-dose gliclazide, by enhancing incretin action, could effectively lower blood glucose without risk of hypoglycemia.
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Affiliation(s)
- Ruth L M Cordiner
- Division of Population Health and Genomics, School of Medicine, University of Dundee, UK
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padua, Italy
| | - Andrea Tura
- Institute of Neuroscience, National Research Council, Padua, Italy
| | - Ewan R Pearson
- Division of Population Health and Genomics, School of Medicine, University of Dundee, UK
- Correspondence: Professor Ewan Pearson, Head of Division, Population Health & Genomics, School of Medicine, University of Dundee, DD1 9SY, UK.
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Nikitin ES, Vinogradova LV. Potassium channels as prominent targets and tools for the treatment of epilepsy. Expert Opin Ther Targets 2021; 25:223-235. [PMID: 33754930 DOI: 10.1080/14728222.2021.1908263] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION K+ channels are of great interest to epilepsy research as mutations in their genes are found in humans with inherited epilepsy. At the level of cellular physiology, K+ channels control neuronal intrinsic excitability and are the main contributors to membrane repolarization of active neurons. Recently, a genetically modified voltage-dependent K+ channel has been patented as a remedy for epileptic seizures. AREAS COVERED We review the role of potassium channels in excitability, clinical and experimental evidence for the association of potassium channelopathies with epilepsy, the targeting of K+ channels by drugs, and perspectives of gene therapy in epilepsy with the expression of extra K+ channels in the brain. EXPERT OPINION Control over K+ conductance is of great potential benefit for the treatment of epilepsy. Nowadays, gene therapy affecting K+ channels is one of the most promising approaches to treat pharmacoresistant focal epilepsy.
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Affiliation(s)
- E S Nikitin
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - L V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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Ahmad SF, Ahmad KA, Ng YT. Neonatal Epileptic Encephalopathies. Semin Pediatr Neurol 2021; 37:100880. [PMID: 33892847 DOI: 10.1016/j.spen.2021.100880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/07/2021] [Accepted: 02/20/2021] [Indexed: 11/26/2022]
Abstract
The majority of neonatal seizures are related to common diagnoses, including hypoxic-ischemic encephalopathy and intraventricular hemorrhage. While relatively uncommon, neonatal epileptic encephalopathies represent an important group of neonatal seizure disorders that require immediate diagnosis and intervention. In this review, we provide a summary of the benign and severe neonatal epilepsy syndromes. While benign epilepsy syndromes have favorable prognoses, rapid and accurate diagnosis may prevent an unnecessarily long course of antiseizure medications. The severe epilepsy syndromes may be related to a number of underlying genetic disorders and often carry a poor prognosis. Herein we review diagnostic and therapeutic strategies, and provide a set or algorithms for said purposes.
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Affiliation(s)
- Samiya Fatima Ahmad
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX; The Children's Hospital of San Antonio, San Antonio, TX.
| | - Kaashif Aqeeb Ahmad
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX; The Children's Hospital of San Antonio, San Antonio, TX; Pediatrix Medical Group of San Antonio, San Antonio, TX
| | - Yu-Tze Ng
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX; The Children's Hospital of San Antonio, San Antonio, TX
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Structure based analysis of K ATP channel with a DEND syndrome mutation in murine skeletal muscle. Sci Rep 2021; 11:6668. [PMID: 33758250 PMCID: PMC7988048 DOI: 10.1038/s41598-021-86121-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome, the most severe end of neonatal diabetes mellitus, is caused by mutation in the ATP-sensitive potassium (KATP) channel. In addition to diabetes, DEND patients present muscle weakness as one of the symptoms, and although the muscle weakness is considered to originate in the brain, the pathological effects of mutated KATP channels in skeletal muscle remain elusive. Here, we describe the local effects of the KATP channel on muscle by expressing the mutation present in the KATP channels of the DEND syndrome in the murine skeletal muscle cell line C2C12 in combination with computer simulation. The present study revealed that the DEND mutation can lead to a hyperpolarized state of the muscle cell membrane, and molecular dynamics simulations based on a recently reported high-resolution structure provide an explanation as to why the mutation reduces ATP sensitivity and reveal the changes in the local interactions between ATP molecules and the channel.
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Sanchez Caballero L, Gorgogietas V, Arroyo MN, Igoillo-Esteve M. Molecular mechanisms of β-cell dysfunction and death in monogenic forms of diabetes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:139-256. [PMID: 33832649 DOI: 10.1016/bs.ircmb.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monogenetic forms of diabetes represent 1%-5% of all diabetes cases and are caused by mutations in a single gene. These mutations, that affect genes involved in pancreatic β-cell development, function and survival, or insulin regulation, may be dominant or recessive, inherited or de novo. Most patients with monogenic diabetes are very commonly misdiagnosed as having type 1 or type 2 diabetes. The severity of their symptoms depends on the nature of the mutation, the function of the affected gene and, in some cases, the influence of additional genetic or environmental factors that modulate severity and penetrance. In some patients, diabetes is accompanied by other syndromic features such as deafness, blindness, microcephaly, liver and intestinal defects, among others. The age of diabetes onset may also vary from neonatal until early adulthood manifestations. Since the different mutations result in diverse clinical presentations, patients usually need different treatments that range from just diet and exercise, to the requirement of exogenous insulin or other hypoglycemic drugs, e.g., sulfonylureas or glucagon-like peptide 1 analogs to control their glycemia. As a consequence, awareness and correct diagnosis are crucial for the proper management and treatment of monogenic diabetes patients. In this chapter, we describe mutations causing different monogenic forms of diabetes associated with inadequate pancreas development or impaired β-cell function and survival, and discuss the molecular mechanisms involved in β-cell demise.
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Affiliation(s)
- Laura Sanchez Caballero
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Vyron Gorgogietas
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Maria Nicol Arroyo
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/.
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Senik MH, Abu IF, Fadhullah W. Analysis of K ATP Channels Opening Probability of Hippocampus Cells Treated with Kainic Acid. Malays J Med Sci 2021; 28:15-26. [PMID: 33679216 PMCID: PMC7909348 DOI: 10.21315/mjms2021.28.1.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/12/2020] [Indexed: 01/14/2023] Open
Abstract
Background Kainic acid (KA)-induced seizures may be a valuable tool in the assessment of anti-epileptic drug efficacy in complex partial seizures. This study investigated the effects of KA on ATP-sensitive K+ (KATP) channels opening probability (NPo), which plays a crucial role in neuronal activities. Methods For the optimisation and validation protocol, β-cells were plated onto 35 mm plastic petri dishes and maintained in RPMI-1640 media supplemented with 10 mM glucose, 10% FCS and 25 mM of N-2-hydroxyethylpiperazine-N-ethanesulfonic acid (HEPES). The treatment effects of 10 mM glucose and 30 μM fluoxetine on KATP channels NPo of β-cells were assessed via cell-attached patch-clamp recordings. For hippocampus cell experiments, hippocampi were harvested from day 17 of maternal Lister-hooded rat foetus, and then transferred to a Ca2+ and Mg2+-free HEPES-buffered Hank's salt solution (HHSS). The dissociated cells were cultured and plated onto a 25 mm round cover glasses coated with poly-d-lysine (0.1 mg/mL) in a petri dish. The KATP channels NPo of hippocampus cells when perfused with 1 mM and 10 mM of KA were determined. Results NPo of β-cells showed significant decreasing patterns (P < 0.001) when treated with 10 mM glucose 0.048 (0.027) as well as 30 μM fluoxetine 0.190 (0.141) as compared to basal counterpart. In hippocampus cell experiment, a significant increase (P < 0.001) in mean NPo 2.148 (0.175) of neurons when applied with 1 mM of KA as compared to basal was observed. Conclusion The two concentrations of KA used in the study exerted contrasting effects toward the mean of NPo. It is hypothesised that KA at lower concentration (1 mM) opens more KATP channels, leading to hyperpolarisation of the neurons, which may prevent neuronal hyper excitability. No effect was shown in 10 mM KA treatment, suggesting that only lower than 10 mM KA produced significant changes in KATP channels. This implies further validation of KA concentration to be used in the future.
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Affiliation(s)
- Mohd Harizal Senik
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia.,School of Life Sciences, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Izuddin Fahmy Abu
- Institute of Medical Science Technology, Universiti Kuala Lumpur, Kuala Lumpur, Malaysia
| | - Widad Fadhullah
- School of Industrial Technology, Universiti Sains Malaysia, Pulau Pinang, Malaysia
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Zhang H, Colclough K, Gloyn AL, Pollin TI. Monogenic diabetes: a gateway to precision medicine in diabetes. J Clin Invest 2021; 131:142244. [PMID: 33529164 PMCID: PMC7843214 DOI: 10.1172/jci142244] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Monogenic diabetes refers to diabetes mellitus (DM) caused by a mutation in a single gene and accounts for approximately 1%-5% of diabetes. Correct diagnosis is clinically critical for certain types of monogenic diabetes, since the appropriate treatment is determined by the etiology of the disease (e.g., oral sulfonylurea treatment of HNF1A/HNF4A-diabetes vs. insulin injections in type 1 diabetes). However, achieving a correct diagnosis requires genetic testing, and the overlapping of the clinical features of monogenic diabetes with those of type 1 and type 2 diabetes has frequently led to misdiagnosis. Improvements in sequencing technology are increasing opportunities to diagnose monogenic diabetes, but challenges remain. In this Review, we describe the types of monogenic diabetes, including common and uncommon types of maturity-onset diabetes of the young, multiple causes of neonatal DM, and syndromic diabetes such as Wolfram syndrome and lipodystrophy. We also review methods of prioritizing patients undergoing genetic testing, and highlight existing challenges facing sequence data interpretation that can be addressed by forming collaborations of expertise and by pooling cases.
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Affiliation(s)
- Haichen Zhang
- University of Maryland School of Medicine, Department of Medicine, Baltimore, Maryland, USA
| | - Kevin Colclough
- Exeter Genomics Laboratory, Royal Devon and Exeter Hospital, Exeter, United Kingdom
| | - Anna L. Gloyn
- Department of Pediatrics, Division of Endocrinology, and,Stanford Diabetes Research Center, Stanford School of Medicine, Stanford, California, USA
| | - Toni I. Pollin
- University of Maryland School of Medicine, Department of Medicine, Baltimore, Maryland, USA
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Denyer AL, Catchpole B, Davison LJ. Genetics of canine diabetes mellitus part 2: Current understanding and future directions. Vet J 2021; 270:105612. [PMID: 33641811 DOI: 10.1016/j.tvjl.2021.105612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 01/05/2021] [Accepted: 01/12/2021] [Indexed: 02/08/2023]
Abstract
Part 1 of this 2-part review outlined the importance of disease classification in diabetes genetic studies, as well as the ways in which genetic variants may contribute to risk of a complex disease within an individual, or within a particular group of individuals. Part 2, presented here, describes in more detail our current understanding of the genetics of canine diabetes mellitus compared to our knowledge of the human disease. Ongoing work to improve our knowledge, using new technologies, is also introduced.
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Affiliation(s)
- Alice L Denyer
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hatfield, UK
| | - Brian Catchpole
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hatfield, UK
| | - Lucy J Davison
- Department of Clinical Sciences and Services, Royal Veterinary College, Hatfield, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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Ngoc CTB, Dien TM, De Franco E, Ellard S, Houghton JAL, Lan NN, Thao BP, Khanh NN, Flanagan SE, Craig ME, Dung VC. Molecular Genetics, Clinical Characteristics, and Treatment Outcomes of K ATP-Channel Neonatal Diabetes Mellitus in Vietnam National Children's Hospital. Front Endocrinol (Lausanne) 2021; 12:727083. [PMID: 34566892 PMCID: PMC8458931 DOI: 10.3389/fendo.2021.727083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Neonatal diabetes mellitus (NDM) is defined as insulin-requiring persistent hyperglycemia occurring within the first 6 months of life, which can result from mutations in at least 25 different genes. Activating heterozygous mutations in genes encoding either of the subunits of the ATP-sensitive K+ channel (KATP channel; KCNJ11 or ABCC8) of the pancreatic beta cell are the most common cause of permanent NDM and the second most common cause of transient NDM. Patients with NDM caused by KATP channel mutations are sensitive to sulfonylurea (SU) treatment; therefore, their clinical management can be improved by replacing insulin with oral agents. PATIENTS AND METHODS Seventy patients were diagnosed with NDM between May 2008 and May 2021 at Vietnam National Children's Hospital, and molecular genetic testing for all genes known to cause NDM was performed at the Exeter Genomic Laboratory, UK. Patients with ABCC8 or KCNJ11 mutations were transferred from insulin to oral SU. Clinical characteristics, molecular genetics, and annual data relating to glycemic control, SU dose, severe hypoglycemia, and side effects were collected. The main outcomes of interest were SU dose, SU failure (defined as permanent reintroduction of daily insulin), and glycemic control (HbA1c). RESULTS Fifty-four of 70 patients (77%) with NDM harbored a genetic mutation and of these; 27 (50%) had activating heterozygous mutations in ABCC8 or KCNJ11. A total of 21 pathogenic mutations were identified in the 27 patients, including 13 mutations in ABCC8 and 8 mutations in KCNJ11. Overall, 51% had low birth weight (below 3rd percentile), 23 (85%) were diagnosed before 3 months of age, and 23 (85%) presented with diabetic ketoacidosis. At diagnosis, clinical and biochemical findings (mean ± SD) were pH 7.16 ± 0.16; HCO3- , 7.9 ± 7.4 mmol/L; BE, -17.9 ± 9.1 mmol/L; HbA1C, 7.98% ± 2.93%; blood glucose, 36.2 ± 12.3 mmol/L; and C-peptide median, 0.09 (range, 0-1.61 nmol/l). Twenty-six patients were successfully transferred from insulin to SU therapy. In the remaining case, remission of diabetes occurred prior to transfer. Glycemic control on SU treatment was better than on insulin treatment: HbA1c and blood glucose level decreased from 7.58% ± 4.63% and 19.04 ± 14.09 mmol/L when treated with insulin to 5.8 ± 0.94% and 6.87 ± 3.46 mmol/L when treated with SU, respectively. CONCLUSIONS This is the first case series of NDM patients with ABCC8/KCNJ11 mutations reported in Vietnam. SU is safe in the short term for these patients and more effective than insulin therapy, consistent with all studies to date. This is relevant for populations where access to and cost of insulin are problematic, reinforcing the importance of genetic testing for NDM.
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Affiliation(s)
- Can Thi Bich Ngoc
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Tran Minh Dien
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Jayne A. L. Houghton
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Nguyen Ngoc Lan
- Institute of Genome Research, Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam
| | - Bui Phuong Thao
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Nguyen Ngoc Khanh
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
| | - Sarah E. Flanagan
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, United Kingdom
| | - Maria E. Craig
- Institute of Endocrinology and Diabetes, The Children’s Hospital at Westmead/Discipline of Child and Adolescent Health, University of Sydney, Sydney, NSW, Australia
- School of Women’s and Children’s Health, University of New South Wales Medicine, Sydney, NSW, Australia
| | - Vu Chi Dung
- Department of Endocrinology, Metabolism and Genetics, Vietnam National Children’s Hospital, Hanoi, Vietnam
- *Correspondence: Vu Chi Dung,
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36
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He B, Li X, Zhou Z. Continuous spectrum of glucose dysmetabolism due to the KCNJ11 gene mutation-Case reports and review of the literature. J Diabetes 2021; 13:19-32. [PMID: 32935446 DOI: 10.1111/1753-0407.13114] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/20/2020] [Accepted: 09/03/2020] [Indexed: 12/01/2022] Open
Abstract
The KCNJ11 gene encodes the Kir6.2 subunit of the adenosine triphosphate-sensitive potassium (KATP ) channel, which plays a key role in insulin secretion. Monogenic diseases caused by KCNJ11 gene mutation are rare and easily misdiagnosed. It has been shown that mutations in the KCNJ11 gene are associated with neonatal diabetes mellitus (NDM), maturity-onset diabetes of the young 13 (MODY13), type 2 diabetes mellitus (T2DM), and hyperinsulinemic hypoglycemia. We report four patients with KCNJ11 gene mutations and provide a systematic review of the literature. A boy with diabetes onset at the age of 1 month was misdiagnosed as type 1 diabetes mellitus (T1DM) for 12 years and received insulin therapy continuously, resulting in poor glycemic control. He was diagnosed as NDM with KCNJ11 E322K gene mutation, and glibenclamide was given to replace exogenous insulin. The successful transfer time was 4 months, much longer than the previous unsuccessful standard of 4 weeks. The other three patients were two sisters and their mother; the younger sister was misdiagnosed with T1DM at 13 years old, while the elder sister was diagnosed with diabetes (type undefined) at 16 years old. They were treated with insulin for 3 years, with poor glycemic control. Their mother was diagnosed with T2DM and achieved good glycemia control with glimepiride. They were diagnosed as MODY13 because of the autosomal dominant inheritance of two generations, early onset of diabetes before 25 years of age in the two sisters, and the presence of the KCNJ11 N48D gene mutation. All patients successfully transferred to sulfonylureas with excellent glycemic control. Therefore, the wide spectrum of clinical phenotypes of glucose dysmetabolism caused by KCNJ11 should be recognized to reduce misdiagnosis and implement appropriate treatment.
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Affiliation(s)
- Binbin He
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education; National Clinical Research Center for Metabolic Diseases, Changsha, China
| | - Xia Li
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education; National Clinical Research Center for Metabolic Diseases, Changsha, China
| | - Zhiguang Zhou
- Department of Metabolism and Endocrinology, The Second Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Diabetes Immunology (Central South University), Ministry of Education; National Clinical Research Center for Metabolic Diseases, Changsha, China
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37
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Abstract
Neonatal diabetes (ND) appears during the first months of life and is caused by a single gene mutation. It is heterogenous and very different compared to other forms of multi-factorial or polygenic diabetes. Clinically, this form is extremely severe, however, early genetic diagnosis is pivotal for successful therapy. A large palette of genes is demonstrated to be a cause of ND, however, the mechanisms of permanent hyperglycemia are different. This review will give an overview of more frequent genetic mutations causing ND, including the function of the mutated genes and the specific therapy for certain sub-forms.
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Affiliation(s)
- M Kocova
- Medical Faculty, University Cyril and Methodius, Skopje, Republic of Macedonia
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38
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Auerbach A, Cohen A, Ofek Shlomai N, Weinberg-Shukron A, Gulsuner S, King MC, Hemi R, Levy-Lahad E, Abulibdeh A, Zangen D. NKX2-2 Mutation Causes Congenital Diabetes and Infantile Obesity With Paradoxical Glucose-Induced Ghrelin Secretion. J Clin Endocrinol Metab 2020; 105:5895035. [PMID: 32818257 DOI: 10.1210/clinem/dgaa563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/14/2020] [Indexed: 12/12/2022]
Abstract
CONTEXT NKX2-2 is a crucial transcription factor that enables specific β-cell gene expression. Nkx2-2(-/-) mice manifest with severe neonatal diabetes and changes in β-cell progenitor fate into ghrelin-producing cells. In humans, recessive NKX2-2 gene mutations have been recently reported as a novel etiology for neonatal diabetes, with only 3 cases known worldwide. This study describes the genetic analysis, distinctive clinical features, the therapeutic challenges, and the unique pathophysiology causing neonatal diabetes in human NKX2-2 dysfunction. CASE DESCRIPTION An infant with very low birth weight (VLBW) and severe neonatal diabetes (NDM) presented with severe obesity and developmental delay already at age 1 year. The challenge of achieving glycemic control in a VLBW infant was unexpectedly met by a regimen of 3 daily doses of long-acting insulin analogues. Sanger sequencing of known NDM genes (such as ABCC8 and EIF2AK3) was followed by whole-exome sequencing that revealed homozygosity of a pathogenic frameshift variant, c.356delG, p.P119fs64*, in the islet cells transcription factor, NKX2-2. To elucidate the cause for the severe obesity, an oral glucose tolerance test was conducted at age 3.5 years and revealed undetectable C-peptide levels with a paradoxically unexpected 30% increase in ghrelin levels. CONCLUSION Recessive NKX2-2 loss of function causes severe NDM associated with VLBW, childhood obesity, and developmental delay. The severe obesity phenotype is associated with postprandial paradoxical ghrelin secretion, which may be related to human β-cell fate change to ghrelin-secreting cells, recapitulating the finding in Nkx2-2(-/-) mice islet cells.
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Affiliation(s)
- Adi Auerbach
- Division of Pediatric Endocrinology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Amitay Cohen
- Hadassah Mt. Scopus, Department of Pediatrics, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Noa Ofek Shlomai
- Department of Neonatology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Ariella Weinberg-Shukron
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
- Hadassah Medical School, Hebrew University, Jerusalem 9112102, Israel
| | - Suleyman Gulsuner
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, DC
| | - Mary-Claire King
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, DC
| | - Rina Hemi
- Institute of Endocrinology, Chaim Sheba Medical Center, Ramat-Gan, Israel
| | - Ephrat Levy-Lahad
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
- Hadassah Medical School, Hebrew University, Jerusalem 9112102, Israel
| | - Abdulsalam Abulibdeh
- Division of Pediatric Endocrinology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - David Zangen
- Division of Pediatric Endocrinology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
- Hadassah Medical School, Hebrew University, Jerusalem 9112102, Israel
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39
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Pipatpolkai T, Usher S, Stansfeld PJ, Ashcroft FM. New insights into K ATP channel gene mutations and neonatal diabetes mellitus. Nat Rev Endocrinol 2020; 16:378-393. [PMID: 32376986 DOI: 10.1038/s41574-020-0351-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/17/2020] [Indexed: 12/12/2022]
Abstract
The ATP-sensitive potassium channel (KATP channel) couples blood levels of glucose to insulin secretion from pancreatic β-cells. KATP channel closure triggers a cascade of events that results in insulin release. Metabolically generated changes in the intracellular concentrations of adenosine nucleotides are integral to this regulation, with ATP and ADP closing the channel and MgATP and MgADP increasing channel activity. Activating mutations in the genes encoding either of the two types of KATP channel subunit (Kir6.2 and SUR1) result in neonatal diabetes mellitus, whereas loss-of-function mutations cause hyperinsulinaemic hypoglycaemia of infancy. Sulfonylurea and glinide drugs, which bind to SUR1, close the channel through a pathway independent of ATP and are now the primary therapy for neonatal diabetes mellitus caused by mutations in the genes encoding KATP channel subunits. Insight into the molecular details of drug and nucleotide regulation of channel activity has been illuminated by cryo-electron microscopy structures that reveal the atomic-level organization of the KATP channel complex. Here we review how these structures aid our understanding of how the various mutations in the genes encoding Kir6.2 (KCNJ11) and SUR1 (ABCC8) lead to a reduction in ATP inhibition and thereby neonatal diabetes mellitus. We also provide an update on known mutations and sulfonylurea therapy in neonatal diabetes mellitus.
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Affiliation(s)
- Tanadet Pipatpolkai
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Samuel Usher
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences, University of Warwick, Coventry, UK
- Department of Chemistry, University of Warwick, Coventry, UK
| | - Frances M Ashcroft
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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40
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Nicolaides NC, Kanaka-Gantenbein C, Papadopoulou-Marketou N, Sertedaki A, Chrousos GP, Papassotiriou I. Emerging technologies in pediatrics: the paradigm of neonatal diabetes mellitus. Crit Rev Clin Lab Sci 2020; 57:522-531. [PMID: 32356495 DOI: 10.1080/10408363.2020.1752141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In the era of precision medicine, the tremendous progress in next-generation sequencing technologies has allowed the identification of an ever-increasing number of genes associated with known Mendelian disorders. Neonatal diabetes mellitus is a rare, genetically heterogeneous endocrine disorder diagnosed before 6 months of age. It may occur alone or in the context of genetic syndromes. Neonatal diabetes mellitus has been linked with genetic defects in at least 26 genes to date. Novel mutations in these disease-causing genes are being reported, giving us a better knowledge of the molecular events that occur upon insulin biosynthesis and secretion from the pancreatic β-cell. Of great importance, some of the identified genes encode proteins that can be therapeutically targeted by drugs per os, leading to transitioning from insulin to sulfonylureas. In this review, we provide an overview of pancreatic β-cell physiology, present the clinical manifestations and the genetic causes of the different forms of neonatal diabetes, and discuss the application of next-generation sequencing methods in the diagnosis and therapeutic management of neonatal diabetes and on research in this area.
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Affiliation(s)
- Nicolas C Nicolaides
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece.,Division of Endocrinology and Metabolism, Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,University Research Institute of Maternal and Child Health and Precision Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Christina Kanaka-Gantenbein
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - Nektaria Papadopoulou-Marketou
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - Amalia Sertedaki
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
| | - George P Chrousos
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece.,Division of Endocrinology and Metabolism, Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,University Research Institute of Maternal and Child Health and Precision Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - Ioannis Papassotiriou
- Department of Clinical Biochemistry, "Aghia Sophia" Children's Hospital, Athens, Greece.,IFCC Emerging Technologies Division, Emerging Technologies in Pediatric Laboratory Medicine (C-ETPLM), Milano, Italy
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41
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Svalastoga P, Sulen Å, Fehn JR, Aukland SM, Irgens H, Sirnes E, Fevang SKE, Valen E, Elgen IB, Njølstad PR. Intellectual Disability in K ATP Channel Neonatal Diabetes. Diabetes Care 2020; 43:526-533. [PMID: 31932458 DOI: 10.2337/dc19-1013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/25/2019] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Neonatal diabetes has been shown to be associated with high neuropsychiatric morbidity in a genotype-phenotype-dependent manner. However, the specific impact of different mutations on intellectual functioning is still insufficiently characterized. Specifically, only a small number of subjects with developmental delay have been comprehensively assessed, creating a knowledge gap about patients carrying the heaviest burden. RESEARCH DESIGN AND METHODS We assessed the intellectual functioning and mental health of the complete Norwegian population with KATP channel neonatal diabetes. Eight sulfonylurea-treated children (five with the p.V59M genotype [KCNJ11]) were assessed using age-matched control subjects with type 1 diabetes. The investigations included a physical and motor developmental examination, cerebral MRI, psychometrical examination, and questionnaires assessing intellectual capabilities and psychiatric morbidity. RESULTS A strong genotype-phenotype correlation was found, revealing the p.V59M genotype as highly associated with substantial intellectual disability, with no significant correlation with the time of sulfonylurea initiation. Consistent with previous studies, other genotypes were associated with minor cognitive impairment. Cerebral MRI verified normal brain anatomy in all but one child. CONCLUSIONS We here presented a comprehensive assessment of intellectual functioning in the largest cohort of p.V59M subjects to date. The level of intellectual disability revealed not only changes the interpretation of other psychological measures but downplays a strong protective effect of sulfonylurea. Within the scope of this study, we could not find evidence supporting an early treatment start to be beneficial, although a weaker effect cannot be ruled out.
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Affiliation(s)
- Pernille Svalastoga
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Pediatrics and Adolescents, Haukeland University Hospital, Bergen, Norway
| | - Åsta Sulen
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Jarle R Fehn
- Department of Child and Adolescent Psychiatry, Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Stein M Aukland
- Department of Radiology, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Henrik Irgens
- Department of Pediatrics and Adolescents, Haukeland University Hospital, Bergen, Norway
| | - Eivind Sirnes
- Department of Pediatrics and Adolescents, Haukeland University Hospital, Bergen, Norway
| | - Silje K E Fevang
- Department of Child and Adolescent Psychiatry, Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Eivind Valen
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
| | - Irene B Elgen
- Department of Child and Adolescent Psychiatry, Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Pål R Njølstad
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway .,Department of Pediatrics and Adolescents, Haukeland University Hospital, Bergen, Norway
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42
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Devaraja J, Elder C, Scott A. Non classic presentations of a genetic mutation typically associated with transient neonatal diabetes. Endocrinol Diabetes Metab Case Rep 2020; 2020:EDM190125. [PMID: 32101525 PMCID: PMC7077548 DOI: 10.1530/edm-19-0125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 02/07/2020] [Indexed: 12/02/2022] Open
Abstract
SUMMARY This case report describes a family pedigree of a mother and her children with an E227K mutation in the KCNJ11 gene. People with this particular gene mutation typically present with transient neonatal diabetes; with more than half the cohort relapsing into permanent diabetes in adolescence or early adulthood. However, the mother developed diabetes as an adolescent and thus was initially diagnosed as having Type 1 Diabetes. All her children have inherited the same genetic mutation but with differing presentations. Her second, third and fourth child presented with transient neonatal diabetes which remitted at varying times. Her first child is 16 years old but had not developed diabetes at the time of writing. The KCNJ11 gene codes for the KIR6.2 subunit of the KATP channels of the pancreatic beta cells. Mutations in this gene limit insulin release from beta cells despite high blood glucose concentrations. Most people with diabetes caused by this genetic mutation can be successfully managed with glibenclamide. Learning of the genetic mutation changed the therapeutic approach to the mother's diabetes and enabled rapid diagnosis for her children. Through this family, we identified that an identical genetic mutation does not necessarily lead to the same diabetic phenotype. We recommend clinicians to consider screening for this gene in their patients whom MODY is suspected; especially in those presenting before the age of 25 who remain C-peptide positive. LEARNING POINTS KATP channel closure in pancreatic beta cells is a critical step in stimulating insulin release. Mutations in the KIR6.2 subunit can result in the KATP channels remaining open, limiting insulin release. People with KCNJ11 mutations may not present with neonatal diabetes as the age of presentation of diabetes can be highly variable. Most affected individuals can be treated successfully with glibenclamide, which closes the KATP channels via an independent mechanism. All first degree relatives of the index case should be offered genetic testing, including asymptomatic individuals. Offspring of affected individuals should be monitored for neonatal diabetes from birth. Affected individuals will require long-term follow-up as there is a high risk of recurrence in later life.
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Affiliation(s)
| | | | - Adrian Scott
- Academic Directorate of Diabetes & Endocrinology at Sheffield Teaching Hospital NHS Trust, Sheffield, UK
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43
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De Franco E, Saint-Martin C, Brusgaard K, Knight Johnson AE, Aguilar-Bryan L, Bowman P, Arnoux JB, Larsen AR, Sanyoura M, Greeley SAW, Calzada-León R, Harman B, Houghton JAL, Nishimura-Meguro E, Laver TW, Ellard S, Del Gaudio D, Christesen HT, Bellanné-Chantelot C, Flanagan SE. Update of variants identified in the pancreatic β-cell K ATP channel genes KCNJ11 and ABCC8 in individuals with congenital hyperinsulinism and diabetes. Hum Mutat 2020; 41:884-905. [PMID: 32027066 PMCID: PMC7187370 DOI: 10.1002/humu.23995] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/08/2020] [Accepted: 02/04/2020] [Indexed: 01/03/2023]
Abstract
The most common genetic cause of neonatal diabetes and hyperinsulinism is pathogenic variants in ABCC8 and KCNJ11. These genes encode the subunits of the β-cell ATP-sensitive potassium channel, a key component of the glucose-stimulated insulin secretion pathway. Mutations in the two genes cause dysregulated insulin secretion; inactivating mutations cause an oversecretion of insulin, leading to congenital hyperinsulinism, whereas activating mutations cause the opposing phenotype, diabetes. This review focuses on variants identified in ABCC8 and KCNJ11, the phenotypic spectrum and the treatment implications for individuals with pathogenic variants.
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Affiliation(s)
- Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Cécile Saint-Martin
- Department of Genetics, Pitié-Salpêtrière Hospital, AP-HP, Sorbonne University, Paris, France
| | - Klaus Brusgaard
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Amy E Knight Johnson
- Department of Human Genetics, University of Chicago Genetic Services Laboratory, The University of Chicago, Chicago, Illinois
| | | | - Pamela Bowman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Jean-Baptiste Arnoux
- Reference Center for Inherited Metabolic Diseases, Necker-Enfants Malades Hospital, Paris, France
| | - Annette Rønholt Larsen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
| | - May Sanyoura
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, Kovler Diabetes Center, University of Chicago, Chicago, Illinois
| | - Siri Atma W Greeley
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, Kovler Diabetes Center, University of Chicago, Chicago, Illinois
| | - Raúl Calzada-León
- Pediatric Endocrinology, Endocrine Service, National Institute for Pediatrics, Mexico City, Mexico
| | - Bradley Harman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Jayne A L Houghton
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Elisa Nishimura-Meguro
- Department of Pediatric Endocrinology, Children's Hospital, National Medical Center XXI Century, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Thomas W Laver
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.,Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Daniela Del Gaudio
- Department of Human Genetics, University of Chicago Genetic Services Laboratory, The University of Chicago, Chicago, Illinois
| | - Henrik Thybo Christesen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark.,Odense Pancreas Center, Odense University Hospital, Odense, Denmark
| | | | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
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44
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Sousa M, Bruges-Armas J. Monogenic Diabetes: Genetics and Relevance on Diabetes Mellitus Personalized Medicine. Curr Diabetes Rev 2020; 16:807-819. [PMID: 31886753 DOI: 10.2174/1573399816666191230114352] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/11/2019] [Accepted: 12/12/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Diabetes mellitus (DM) is a complex disease with significant impression in today's world. Aside from the most common types recognized over the years, such as type 1 diabetes (T1DM) and type 2 diabetes (T2DM), recent studies have emphasized the crucial role of genetics in DM, allowing the distinction of monogenic diabetes. METHODS Authors did a literature search with the purpose of highlighting and clarifying the subtypes of monogenic diabetes, as well as the accredited genetic entities responsible for such phenotypes. RESULTS The following subtypes were included in this literature review: maturity-onset diabetes of the young (MODY), neonatal diabetes mellitus (NDM) and maternally inherited diabetes and deafness (MIDD). So far, 14 subtypes of MODY have been identified, while three subtypes have been identified in NDM - transient, permanent, and syndromic. DISCUSSION Despite being estimated to affect approximately 2% of all the T2DM patients in Europe, the exact prevalence of MODY is still unknown, accentuating the need for research focused on biomarkers. Consequently, due to its impact in the course of treatment, follow-up of associated complications, and genetic implications for siblings and offspring of affected individuals, it is imperative to diagnose the monogenic forms of DM accurately. CONCLUSION Currently, advances in the genetics field allowed the recognition of new DM subtypes, which until now, were considered slight variations of the typical forms. Thus, it is imperative to act in the close interaction between genetics and clinical manifestations, to facilitate diagnosis and individualize treatment.
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MESH Headings
- Deafness/classification
- Deafness/diagnosis
- Deafness/genetics
- Diabetes Mellitus, Type 1/diagnosis
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 2/classification
- Diabetes Mellitus, Type 2/diagnosis
- Diabetes Mellitus, Type 2/genetics
- Genetic Testing
- Genotype
- Humans
- Infant
- Infant, Newborn
- Infant, Newborn, Diseases/classification
- Infant, Newborn, Diseases/diagnosis
- Infant, Newborn, Diseases/genetics
- Mitochondrial Diseases/classification
- Mitochondrial Diseases/diagnosis
- Mitochondrial Diseases/genetics
- Mutation
- Phenotype
- Precision Medicine
- Syndrome
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Affiliation(s)
- Madalena Sousa
- Serviço Especializado de Epidemiologia e Biologia Molecular (SEEBMO), Hospital de Santo Espírito da Ilha Terceira (HSEIT), Angra do Heroísmo, Azores, Portugal
| | - Jácome Bruges-Armas
- Serviço Especializado de Epidemiologia e Biologia Molecular (SEEBMO), Hospital de Santo Espírito da Ilha Terceira (HSEIT), Angra do Heroísmo, Azores, Portugal
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45
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Tas E, Garibaldi L, Muzumdar R. Glucose Homeostasis in Newborns: An Endocrinology Perspective. Neoreviews 2020; 21:e14-e29. [PMID: 31894079 DOI: 10.1542/neo.21-1-e14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Physiologic adaptations in the postnatal period, along with gradual establishment of enteral feeding, help maintain plasma glucose concentrations in the neonatal period. The definition of normal plasma glucose in the neonatal period has been a subject of debate because of a lack of evidence linking a set plasma or blood glucose concentration to clinical symptoms or predictors of short- and long-term outcomes. However, there is consensus that maintaining plasma glucose in the normal range for age is important to prevent immediate and long-term neurodevelopmental consequences of hypoglycemia or hyperglycemia. The specific management strategy for abnormal glucose levels in neonates depends on the underlying etiology, and interventions could include nutritional changes, medications, hormone therapy, or even surgery. Here, we will review the physiological processes that help maintain plasma glucose in newborns and discuss the approach to a newborn with disordered glucose homeostasis, with an emphasis on the endocrine basis of abnormal glucose homeostasis.
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Affiliation(s)
- Emir Tas
- Division of Endocrinology and Diabetes, Department of Pediatrics, Arkansas Children's Hospital, Little Rock, AR
| | - Luigi Garibaldi
- Division of Endocrinology, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - Radhika Muzumdar
- Division of Endocrinology, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA
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46
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Letourneau LR, Greeley SAW. Precision Medicine: Long-Term Treatment with Sulfonylureas in Patients with Neonatal Diabetes Due to KCNJ11 Mutations. Curr Diab Rep 2019; 19:52. [PMID: 31250216 PMCID: PMC6894166 DOI: 10.1007/s11892-019-1175-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE OF REVIEW The goal of this review is to provide updates on the safety and efficacy of long-term sulfonylurea use in patients with KCNJ11-related diabetes. Publications from 2004 to the present were reviewed with an emphasis on literature since 2014. RECENT FINDINGS Sulfonylureas, often taken at high doses, have now been utilized effectively in KCNJ11 patients for over 10 years. Mild-moderate hypoglycemia can occur, but in two studies with a combined 975 patient-years on sulfonylureas, no severe hypoglycemic events were reported. Improvements in neurodevelopment and motor function after transition to sulfonylureas continue to be described. Sulfonylureas continue to be an effective, sustainable, and safe treatment for KCNJ11-related diabetes. Ongoing follow-up of patients in research registries will allow for deeper understanding of the facilitators and barriers to long-term sustainability. Further understanding of the effect of sulfonylurea on long-term neurodevelopmental outcomes, and the potential for adjunctive therapies, is needed.
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Affiliation(s)
- Lisa R Letourneau
- Section of Pediatric and Adult Endocrinology, Diabetes, and Metabolism Kovler Diabetes Center, University of Chicago, 5841 S. Maryland Ave., MC1027-N235, Chicago, IL, 60637, USA
| | - Siri Atma W Greeley
- Section of Pediatric and Adult Endocrinology, Diabetes, and Metabolism Kovler Diabetes Center, University of Chicago, 5841 S. Maryland Ave., MC1027-N235, Chicago, IL, 60637, USA.
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47
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Wang X, Sterr M, Ansarullah, Burtscher I, Böttcher A, Beckenbauer J, Siehler J, Meitinger T, Häring HU, Staiger H, Cernilogar FM, Schotta G, Irmler M, Beckers J, Wright CVE, Bakhti M, Lickert H. Point mutations in the PDX1 transactivation domain impair human β-cell development and function. Mol Metab 2019; 24:80-97. [PMID: 30930126 PMCID: PMC6531841 DOI: 10.1016/j.molmet.2019.03.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/04/2019] [Accepted: 03/13/2019] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE Hundreds of missense mutations in the coding region of PDX1 exist; however, if these mutations predispose to diabetes mellitus is unknown. METHODS In this study, we screened a large cohort of subjects with increased risk for diabetes and identified two subjects with impaired glucose tolerance carrying common, heterozygous, missense mutations in the PDX1 coding region leading to single amino acid exchanges (P33T, C18R) in its transactivation domain. We generated iPSCs from patients with heterozygous PDX1P33T/+, PDX1C18R/+ mutations and engineered isogenic cell lines carrying homozygous PDX1P33T/P33T, PDX1C18R/C18R mutations and a heterozygous PDX1 loss-of-function mutation (PDX1+/-). RESULTS Using an in vitro β-cell differentiation protocol, we demonstrated that both, heterozygous PDX1P33T/+, PDX1C18R/+ and homozygous PDX1P33T/P33T, PDX1C18R/C18R mutations impair β-cell differentiation and function. Furthermore, PDX1+/- and PDX1P33T/P33T mutations reduced differentiation efficiency of pancreatic progenitors (PPs), due to downregulation of PDX1-bound genes, including transcription factors MNX1 and PDX1 as well as insulin resistance gene CES1. Additionally, both PDX1P33T/+ and PDX1P33T/P33T mutations in PPs reduced the expression of PDX1-bound genes including the long-noncoding RNA, MEG3 and the imprinted gene NNAT, both involved in insulin synthesis and secretion. CONCLUSIONS Our results reveal mechanistic details of how common coding mutations in PDX1 impair human pancreatic endocrine lineage formation and β-cell function and contribute to the predisposition for diabetes.
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Affiliation(s)
- Xianming Wang
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, Ismaningerstraße 22, 81675 München, Germany
| | - Michael Sterr
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, Ismaningerstraße 22, 81675 München, Germany
| | - Ansarullah
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Ingo Burtscher
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Anika Böttcher
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Julia Beckenbauer
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Johanna Siehler
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, Ismaningerstraße 22, 81675 München, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen, 72076 Tübingen, Germany; Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, University of Tübingen, 72076 Tübingen, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Harald Staiger
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tübingen, 72076 Tübingen, Germany; Institute of Pharmaceutical Sciences, Department of Pharmacy and Biochemistry, Eberhard Karls University Tübingen, 72076 Tübingen, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Filippo M Cernilogar
- Biomedical Center and Center for Integrated Protein Science Munich, Ludwig-Maximilians-University, 82152 Planegg-Martinsried, Germany
| | - Gunnar Schotta
- Biomedical Center and Center for Integrated Protein Science Munich, Ludwig-Maximilians-University, 82152 Planegg-Martinsried, Germany
| | - Martin Irmler
- Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Johannes Beckers
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute of Experimental Genetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Chair of Experimental Genetics, School of Life Sciences Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - Christopher V E Wright
- Vanderbilt University Program in Developmental Biology, Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Mostafa Bakhti
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Technische Universität München, Ismaningerstraße 22, 81675 München, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
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48
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Bowman P, Day J, Torrens L, Shepherd MH, Knight BA, Ford TJ, Flanagan SE, Chakera A, Hattersley AT, Zeman A. Cognitive, Neurological, and Behavioral Features in Adults With KCNJ11 Neonatal Diabetes. Diabetes Care 2019; 42:215-224. [PMID: 30377186 PMCID: PMC6354912 DOI: 10.2337/dc18-1060] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/22/2018] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Central nervous system (CNS) features in children with permanent neonatal diabetes (PNDM) due to KCNJ11 mutations have a major impact on affected families. Sulfonylurea therapy achieves outstanding metabolic control but only partial improvement in CNS features. The effects of KCNJ11 mutations on the adult brain and their functional impact are not well understood. We aimed to characterize the CNS features in adults with KCNJ11 PNDM compared with adults with INS PNDM. RESEARCH DESIGN AND METHODS Adults with PNDM due to KCNJ11 mutations (n = 8) or INS mutations (n = 4) underwent a neurological examination and completed standardized neuropsychological tests/questionnaires about development/behavior. Four individuals in each group underwent a brain MRI scan. Test scores were converted to Z scores using normative data, and outcomes were compared between groups. RESULTS In individuals with KCNJ11 mutations, neurological examination was abnormal in seven of eight; predominant features were subtle deficits in coordination/motor sequencing. All had delayed developmental milestones and/or required learning support/special schooling. Half had features and/or a clinical diagnosis of autism spectrum disorder. KCNJ11 mutations were also associated with impaired attention, working memory, and perceptual reasoning and reduced intelligence quotient (IQ) (median IQ KCNJ11 vs. INS mutations 76 vs. 111, respectively; P = 0.02). However, no structural brain abnormalities were noted on MRI. The severity of these features was related to the specific mutation, and they were absent in individuals with INS mutations. CONCLUSIONS KCNJ11 PNDM is associated with specific CNS features that are not due to long-standing diabetes, persist into adulthood despite sulfonylurea therapy, and represent the major burden from KCNJ11 mutations.
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Affiliation(s)
- Pamela Bowman
- University of Exeter Medical School, Exeter, U.K. .,Exeter National Institute for Health Research Clinical Research Facility, Exeter, U.K
| | - Jacob Day
- University of Exeter Medical School, Exeter, U.K.,Exeter National Institute for Health Research Clinical Research Facility, Exeter, U.K
| | - Lorna Torrens
- Kent Neuropsychology Service, Kent and Medway NHS and Social Care Partnership Trust, Gillingham, U.K
| | - Maggie H Shepherd
- University of Exeter Medical School, Exeter, U.K.,Exeter National Institute for Health Research Clinical Research Facility, Exeter, U.K
| | - Bridget A Knight
- University of Exeter Medical School, Exeter, U.K.,Exeter National Institute for Health Research Clinical Research Facility, Exeter, U.K
| | | | | | - Ali Chakera
- University of Exeter Medical School, Exeter, U.K.,Exeter National Institute for Health Research Clinical Research Facility, Exeter, U.K
| | - Andrew T Hattersley
- University of Exeter Medical School, Exeter, U.K.,Exeter National Institute for Health Research Clinical Research Facility, Exeter, U.K
| | - Adam Zeman
- University of Exeter Medical School, Exeter, U.K
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49
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Veeraragavulu P, Yellapu NK, Yerrathota S, Adi PJ, Matcha B. Three Novel Mutations I65S, R66S, and G86R Divulge Significant Conformational Variations in the PTB Domain of the IRS1 Gene. ACS OMEGA 2019; 4:2217-2224. [PMID: 31660472 PMCID: PMC6814177 DOI: 10.1021/acsomega.8b01712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/25/2018] [Indexed: 06/10/2023]
Abstract
Insulin receptor substrate 1 (IRS1) is one of the major substrates for the IR, and their interaction mediates several downstream insulin signaling pathways. In this study, we have identified three novel mutations in the IRS1 gene of type 2 diabetic (T2D) patients, which reflected in the amino acid changes as I65S, R66S, and G86R in the phosphotyrosine binding domain of the IRS1 protein. The impact of these mutations on the structure and function of the IRS1 protein was evaluated through molecular modeling studies, and distinct conformational fluctuations were recorded. The variable binding affinities and positional displacement of these mutant models were observed in the ligand-binding cleft of IR. The mutant IRS1 models triggered conformational changes in the L1 domain of IR upon their binding. Such structural variations in IRS1 and IR structures due to mutations resulted in variable molecular interactions that could lead to altered insulin transduction, followed by insulin resistance and T2D.
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Affiliation(s)
| | - Nanda Kumar Yellapu
- Division
of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati 517502, India
| | - Sireesha Yerrathota
- Division
of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati 517502, India
| | - Pradeepkiran Jangampalli Adi
- Division
of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati 517502, India
- Garrison
Institute on Aging, Texas Tech University
Health Sciences Center, 3601 4th Street, MS 9424, Lubbock, Texas 79430, United
States
| | - Bhaskar Matcha
- Division
of Animal Biotechnology, Department of Zoology, Sri Venkateswara University, Tirupati 517502, India
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50
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Madani H, Elkaffas R, Alkholy B, Musa N, Shaalan Y, Elkaffas R, Hassan M, Hafez M, Flanagan SE, De Franco E, Hussain K. Identification of novel variants in neonatal diabetes mellitus genes in Egyptian patients with permanent NDM. Int J Diabetes Dev Ctries 2019. [DOI: 10.1007/s13410-018-0658-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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