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Rutter GA, Gresch A, Delgadillo Silva L, Benninger RKP. Exploring pancreatic beta-cell subgroups and their connectivity. Nat Metab 2024:10.1038/s42255-024-01097-6. [PMID: 39117960 DOI: 10.1038/s42255-024-01097-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 07/05/2024] [Indexed: 08/10/2024]
Abstract
Functional pancreatic islet beta cells are essential to ensure glucose homeostasis across species from zebrafish to humans. These cells show significant heterogeneity, and emerging studies have revealed that connectivity across a hierarchical network is required for normal insulin release. Here, we discuss current thinking and areas of debate around intra-islet connectivity, cellular hierarchies and potential "controlling" beta-cell populations. We focus on methodologies, including comparisons of different cell preparations as well as in vitro and in vivo approaches to imaging and controlling the activity of human and rodent islet preparations. We also discuss the analytical approaches that can be applied to live-cell data to identify and study critical subgroups of cells with a disproportionate role in control Ca2+ dynamics and thus insulin secretion (such as "first responders", "leaders" and "hubs", as defined by Ca2+ responses to glucose stimulation). Possible mechanisms by which this hierarchy is achieved, its physiological relevance and how its loss may contribute to islet failure in diabetes mellitus are also considered. A glossary of terms and links to computational resources are provided.
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Affiliation(s)
- Guy A Rutter
- CHUM Research Center and Faculty of Medicine, University of Montréal, Montréal, QC, Canada.
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
| | - Anne Gresch
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Luis Delgadillo Silva
- CHUM Research Center and Faculty of Medicine, University of Montréal, Montréal, QC, Canada
| | - Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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2
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Dalle S, Abderrahmani A. Receptors and Signaling Pathways Controlling Beta-Cell Function and Survival as Targets for Anti-Diabetic Therapeutic Strategies. Cells 2024; 13:1244. [PMID: 39120275 PMCID: PMC11311556 DOI: 10.3390/cells13151244] [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: 06/18/2024] [Revised: 07/19/2024] [Accepted: 07/21/2024] [Indexed: 08/10/2024] Open
Abstract
Preserving the function and survival of pancreatic beta-cells, in order to achieve long-term glycemic control and prevent complications, is an essential feature for an innovative drug to have clinical value in the treatment of diabetes. Innovative research is developing therapeutic strategies to prevent pathogenic mechanisms and protect beta-cells from the deleterious effects of inflammation and/or chronic hyperglycemia over time. A better understanding of receptors and signaling pathways, and of how they interact with each other in beta-cells, remains crucial and is a prerequisite for any strategy to develop therapeutic tools aimed at modulating beta-cell function and/or mass. Here, we present a comprehensive review of our knowledge on membrane and intracellular receptors and signaling pathways as targets of interest to protect beta-cells from dysfunction and apoptotic death, which opens or could open the way to the development of innovative therapies for diabetes.
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Affiliation(s)
- Stéphane Dalle
- Institut de Génomique Fonctionnelle, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), 34094 Montpellier, France
| | - Amar Abderrahmani
- Université Lille, Centre National de la Recherche Scientifique (CNRS), Centrale Lille, Université Polytechnique Hauts-de-France, UMR 8520, IEMN, F59000 Lille, France
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3
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Lee YM, Lin PR, Sia HK. Oral antidiabetic therapy versus early insulinization on glycemic control in newly diagnosed type 2 diabetes patients: a retrospective matched cohort study. Sci Rep 2024; 14:15491. [PMID: 38969701 PMCID: PMC11226661 DOI: 10.1038/s41598-024-66468-1] [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: 02/29/2024] [Accepted: 07/01/2024] [Indexed: 07/07/2024] Open
Abstract
Our study aims to compare the efficacy of oral antidiabetic therapy to early insulinization on glycemic control among newly diagnosed type 2 diabetes patients in real-world clinical practice. A retrospective cohort study conducted at a medical center in Taiwan analyzed 1256 eligible patients from January 2007 to December 2017. Propensity score matching resulted in well-balanced groups of 94 patients each in the oral antidiabetic drug (OAD) and early insulinization cohorts. Glycemic outcomes were assessed in both groups. Patients exclusively using OAD showed consistently lower glycated hemoglobin (HbA1c) levels at 3, 12, 24, and 36 months compared to insulin users. At later periods, 77.7% of OAD users achieved glycemic control versus 64.9% of insulin users, with a marginally significant difference. Subgroup analyses suggested a trend favoring well-controlled diabetes in the OAD group, though not statistically significant. Our study finds oral antidiabetic therapy is not inferior to early insulinization for glycemic control in newly diagnosed type 2 diabetes patients, irrespective of initial HbA1c levels. This supports oral therapy as a rational treatment option, even in cases with elevated HbA1c at diagnosis.
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Affiliation(s)
- Yang-Ming Lee
- Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan.
- Department of Endocrinology and Metabolism, Changhua Christian Hospital, 135 Nanhsiao Street, Changhua, 500, Taiwan.
| | - Pei Ru Lin
- Big Data Center, Changhua Christian Hospital, Changhua, 500, Taiwan
- Graduate Institute of Statistics and Information Science, National Changhua University of Education, Changhua, 500, Taiwan
| | - Hon-Ke Sia
- Department of Endocrinology and Metabolism, Changhua Christian Hospital, 135 Nanhsiao Street, Changhua, 500, Taiwan.
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, Taichung, Taiwan.
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4
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Rohli KE, Stubbe NJ, Walker EM, Pearson GL, Soleimanpour SA, Stephens SB. A metabolic redox relay supports ER proinsulin export in pancreatic islet β cells. JCI Insight 2024; 9:e178725. [PMID: 38935435 PMCID: PMC11383593 DOI: 10.1172/jci.insight.178725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 06/18/2024] [Indexed: 06/29/2024] Open
Abstract
ER stress and proinsulin misfolding are heralded as contributing factors to β cell dysfunction in type 2 diabetes, yet how ER function becomes compromised is not well understood. Recent data identify altered ER redox homeostasis as a critical mechanism that contributes to insulin granule loss in diabetes. Hyperoxidation of the ER delays proinsulin export and limits the proinsulin supply available for insulin granule formation. In this report, we identified glucose metabolism as a critical determinant in the redox homeostasis of the ER. Using multiple β cell models, we showed that loss of mitochondrial function or inhibition of cellular metabolism elicited ER hyperoxidation and delayed ER proinsulin export. Our data further demonstrated that β cell ER redox homeostasis was supported by the metabolic supply of reductive redox donors. We showed that limiting NADPH and thioredoxin flux delayed ER proinsulin export, whereas thioredoxin-interacting protein suppression restored ER redox and proinsulin trafficking. Taken together, we propose that β cell ER redox homeostasis is buffered by cellular redox donor cycles, which are maintained through active glucose metabolism.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Emily M Walker
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Gemma L Pearson
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Scott A Soleimanpour
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- VA Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
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5
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Dalle S. Targeting Protein Kinases to Protect Beta-Cell Function and Survival in Diabetes. Int J Mol Sci 2024; 25:6425. [PMID: 38928130 PMCID: PMC11203834 DOI: 10.3390/ijms25126425] [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: 04/30/2024] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
The prevalence of diabetes is increasing worldwide. Massive death of pancreatic beta-cells causes type 1 diabetes. Progressive loss of beta-cell function and mass characterizes type 2 diabetes. To date, none of the available antidiabetic drugs promotes the maintenance of a functional mass of endogenous beta-cells, revealing an unmet medical need. Dysfunction and apoptotic death of beta-cells occur, in particular, through the activation of intracellular protein kinases. In recent years, protein kinases have become highly studied targets of the pharmaceutical industry for drug development. A number of drugs that inhibit protein kinases have been approved for the treatment of cancers. The question of whether safe drugs that inhibit protein kinase activity can be developed and used to protect the function and survival of beta-cells in diabetes is still unresolved. This review presents arguments suggesting that several protein kinases in beta-cells may represent targets of interest for the development of drugs to treat diabetes.
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Affiliation(s)
- Stéphane Dalle
- Institut de Génomique Fonctionnelle, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), 34094 Montpellier, France
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6
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Patel S, Remedi MS. Loss of β-cell identity and dedifferentiation, not an irreversible process? Front Endocrinol (Lausanne) 2024; 15:1414447. [PMID: 38915897 PMCID: PMC11194313 DOI: 10.3389/fendo.2024.1414447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 05/27/2024] [Indexed: 06/26/2024] Open
Abstract
Type 2 diabetes (T2D) is a polygenic metabolic disorder characterized by insulin resistance in peripheral tissues and impaired insulin secretion by the pancreas. While the decline in insulin production and secretion was previously attributed to apoptosis of insulin-producing β-cells, recent studies indicate that β-cell apoptosis rates are relatively low in diabetes. Instead, β-cells primarily undergo dedifferentiation, a process where they lose their specialized identity and transition into non-functional endocrine progenitor-like cells, ultimately leading to β-cell failure. The underlying mechanisms driving β-cell dedifferentiation remain elusive due to the intricate interplay of genetic factors and cellular stress. Understanding these mechanisms holds the potential to inform innovative therapeutic approaches aimed at reversing β-cell dedifferentiation in T2D. This review explores the proposed drivers of β-cell dedifferentiation leading to β-cell failure, and discusses current interventions capable of reversing this process, thus restoring β-cell identity and function.
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Affiliation(s)
- Sumit Patel
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, South Euclid Avenue, St. Louis, MO, United States
| | - Maria S. Remedi
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, South Euclid Avenue, St. Louis, MO, United States
- Deparment of Cell Biology and Physiology, Washington University School of Medicine, South Euclid Avenue, St. Louis, MO, United States
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, South Euclid Avenue, St. Louis, MO, United States
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Gignac T, Trépanier G, Pradeau M, Morissette A, Agrinier AL, Larose É, Marois J, Pilon G, Gagnon C, Vohl MC, Marette A, Carreau AM. Metabolic-associated fatty liver disease is characterized by a post-oral glucose load hyperinsulinemia in individuals with mild metabolic alterations. Am J Physiol Endocrinol Metab 2024; 326:E616-E625. [PMID: 38477665 DOI: 10.1152/ajpendo.00294.2023] [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: 09/07/2023] [Revised: 03/07/2024] [Accepted: 03/11/2024] [Indexed: 03/14/2024]
Abstract
Metabolic-associated fatty liver disease (MAFLD) has been identified as risk factor of incident type 2 diabetes (T2D), but the underlying postprandial mechanisms remain unclear. We compared the glucose metabolism, insulin resistance, insulin secretion, and insulin clearance post-oral glucose tolerance test (OGTT) between individuals with and without MAFLD. We included 50 individuals with a body mass index (BMI) between 25 and 40 kg/m2 and ≥1 metabolic alteration: increased fasting triglycerides or insulin, plasma glucose 5.5-6.9 mmol/L, or glycated hemoglobin 5.7-5.9%. Participants were grouped according to MAFLD status, defined as hepatic fat fraction (HFF) ≥5% on MRI. We used oral minimal model on a frequently sampled 3 h 75 g-OGTT to estimate insulin sensitivity, insulin secretion, and pancreatic β-cell function. Fifty percent of participants had MAFLD. Median age (IQR) [57 (45-65) vs. 57 (44-63) yr] and sex (60% vs. 56% female) were comparable between groups. Post-OGTT glucose concentrations did not differ between groups, whereas post-OGTT insulin concentrations were higher in the MAFLD group (P < 0.03). Individuals with MAFLD exhibited lower insulin clearance, insulin sensitivity, and first-phase pancreatic β-cell function. In all individuals, increased insulin incremental area under the curve and decreased insulin clearance were associated with HFF after adjusting for age, sex, and BMI (P < 0.02). Among individuals with metabolic alterations, the presence of MAFLD was characterized mainly by post-OGTT hyperinsulinemia and reduced insulin clearance while exhibiting lower first phase β-cell function and insulin sensitivity. This suggests that MAFLD is linked with impaired insulin metabolism that may precede T2D.NEW & NOTEWORTHY Using an oral glucose tolerance test, we found hyperinsulinemia, lower insulin sensitivity, lower insulin clearance, and lower first-phase pancreatic β-cell function in individuals with MAFLD. This may explain part of the increased risk of incident type 2 diabetes in this population. These data also highlight implications of hyperinsulinemia and impaired insulin clearance in the progression of MAFLD to type 2 diabetes.
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Affiliation(s)
- Théo Gignac
- Axe Endocrinologie et Néphrologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
| | - Gabrielle Trépanier
- Axe Endocrinologie et Néphrologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
| | - Marion Pradeau
- Axe Endocrinologie et Néphrologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
| | - Arianne Morissette
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
- Axe Obésité, Diabète de type 2 et Métabolisme, Centre de recherche de l'IUCPQ-Université Laval, Québec, Quebec, Canada
| | - Anne-Laure Agrinier
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
- Axe Obésité, Diabète de type 2 et Métabolisme, Centre de recherche de l'IUCPQ-Université Laval, Québec, Quebec, Canada
| | - Éric Larose
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
- Axe Obésité, Diabète de type 2 et Métabolisme, Centre de recherche de l'IUCPQ-Université Laval, Québec, Quebec, Canada
| | - Julie Marois
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
| | - Geneviève Pilon
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
- Axe Obésité, Diabète de type 2 et Métabolisme, Centre de recherche de l'IUCPQ-Université Laval, Québec, Quebec, Canada
| | - Claudia Gagnon
- Axe Endocrinologie et Néphrologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
- Axe Obésité, Diabète de type 2 et Métabolisme, Centre de recherche de l'IUCPQ-Université Laval, Québec, Quebec, Canada
| | - Marie-Claude Vohl
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
- École de nutrition, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Quebec, Canada
| | - André Marette
- Centre Nutrition, santé et société (NUTRISS), Institut sur la Nutrition et les Aliments Fonctionnels (INAF), Université Laval, Québec, Quebec, Canada
- Axe Obésité, Diabète de type 2 et Métabolisme, Centre de recherche de l'IUCPQ-Université Laval, Québec, Quebec, Canada
| | - Anne-Marie Carreau
- Axe Endocrinologie et Néphrologie, Centre de Recherche du CHU de Québec-Université Laval, Québec, Quebec, Canada
- Département de Médecine, Faculté de Médecine, Université Laval, Québec, Quebec, Canada
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Yang T, Filippov I, Manathunga L, Baghai A, Maréchal A, Raleigh DP, Zhyvoloup A. On the importance of being amidated: Analysis of the role of the conserved C-terminal amide of amylin in amyloid formation and cytotoxicity. Biophys Chem 2024; 307:107168. [PMID: 38367541 PMCID: PMC11223093 DOI: 10.1016/j.bpc.2023.107168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/17/2023] [Accepted: 12/28/2023] [Indexed: 02/19/2024]
Abstract
The polypeptide hormone Amylin (also known as islet amyloid polypeptide) plays a role in regulation of glucose metabolism, but forms pancreatic islet amyloid deposits in type 2 diabetes. The process of islet amyloid formation contributes to β-cell dysfunction and the development of the disease. Amylin is produced as a pro-from and undergoes processing prior to secretion. The mature hormone contains an amidated C-terminus. Analysis of an alignment of vertebrate amylin sequences reveals that the processing signal for amidation is strictly conserved. Furthermore, the enzyme responsible for C-terminal amidation is found in all of these organisms. Comparison of the physiologically relevant amidated form to a variant with a free C-terminus (Amylin-COO-) shows that replacement of the C-terminal amide with a carboxylate slows, but does not prevent amyloid formation. Pre-fibrillar species produced by both variants are toxic to cultured β-cells, although hAmylin-COO- is moderately less so. Amyloid fibrils produced by either peptide are not toxic. Prior work (ACS Pharmacol. Translational. Sci. 1, 132-49 (2018)) shows that Amylin- COO- exhibits a 58-fold reduction in activation of the Amylin1 receptor and 20-fold reduction in activation of the Amylin3 receptor. Thus, hAmylin-COO- exhibits significant toxicity, but significantly reduced activity and offers a reagent for studies which aim to decouple hAmylin's toxic effects from its activity. The different behaviours of free and C-terminal amidated Amylin should be considered when designing systems to produce the polypeptide recombinantly.
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Affiliation(s)
- Tangweina Yang
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Ivan Filippov
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Lakshan Manathunga
- Laufer Center for Quantitative Biology, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States; Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States
| | - Aria Baghai
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Amandine Maréchal
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck College, London WC1E 7HX, United Kingdom
| | - Daniel P Raleigh
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Laufer Center for Quantitative Biology, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States; Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, NY 11790, United States.
| | - Alexander Zhyvoloup
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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9
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Gandasi NR, Gao R, Kothegala L, Pearce A, Santos C, Acreman S, Basco D, Benrick A, Chibalina MV, Clark A, Guida C, Harris M, Johnson PRV, Knudsen JG, Ma J, Miranda C, Shigeto M, Tarasov AI, Yeung HY, Thorens B, Asterholm IW, Zhang Q, Ramracheya R, Ladds G, Rorsman P. GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of mouse and human pancreatic islet glucagon secretion. Diabetologia 2024; 67:528-546. [PMID: 38127123 PMCID: PMC10844371 DOI: 10.1007/s00125-023-06060-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: 08/16/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
AIMS/HYPOTHESIS Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by β-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.
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Affiliation(s)
- Nikhil R Gandasi
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Cell Metabolism Lab (GA-08), Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Rui Gao
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Lakshmi Kothegala
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Abigail Pearce
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Cristiano Santos
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Samuel Acreman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Davide Basco
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Anna Benrick
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Margarita V Chibalina
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Matthew Harris
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford, UK
- Biomedical Research Centre, Oxford National Institute for Health Research, Churchill Hospital, Oxford, UK
| | - Jakob G Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jinfang Ma
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Caroline Miranda
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Makoto Shigeto
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Ho Yan Yeung
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ingrid W Asterholm
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Reshma Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Patrik Rorsman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden.
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.
- Biomedical Research Centre, Oxford National Institute for Health Research, Churchill Hospital, Oxford, UK.
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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10
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Sue N, Thai LM, Saito A, Boyer CK, Fordham AM, Yan C, Davenport A, Tao J, Bensellam M, Cantley J, Shi YC, Stephens SB, Imaizumi K, Biden TJ. Independent activation of CREB3L2 by glucose fills a regulatory gap in mouse β-cells by co-ordinating insulin biosynthesis with secretory granule formation. Mol Metab 2024; 79:101845. [PMID: 38013154 PMCID: PMC10755490 DOI: 10.1016/j.molmet.2023.101845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 11/29/2023] Open
Abstract
OBJECTIVE Although individual steps have been characterized, there is little understanding of the overall process whereby glucose co-ordinates the biosynthesis of insulin with its export out of the endoplasmic reticulum (ER) and incorporation into insulin secretory granules (ISGs). Here we investigate a role for the transcription factor CREB3L2 in this context. METHODS MIN6 cells and mouse islets were analysed by immunoblotting after treatment with glucose, fatty acids, thapsigargin and various inhibitors. Knockdown of CREB3L2 was achieved using si or sh constructs by transfection, or viral delivery. In vivo metabolic phenotyping was conducted after deletion of CREB3L2 in β-cells of adult mice using Ins1-CreER+. Islets were isolated for RNAseq and assays of glucose-stimulated insulin secretion (GSIS). Trafficking was monitored in islet monolayers using a GFP-tagged proinsulin construct that allows for synchronised release from the ER. RESULTS With a Km ≈3.5 mM, glucose rapidly (T1/2 0.9 h) increased full length (FL) CREB3L2 followed by a slower rise (T1/2 2.5 h) in its transcriptionally-active cleavage product, P60 CREB3L2. Glucose stimulation repressed the ER stress marker, CHOP, and this was partially reverted by knockdown of CREB3L2. Activation of CREB3L2 by glucose was not due to ER stress, however, but a combination of O-GlcNAcylation, which impaired proteasomal degradation of FL-CREB3L2, and mTORC1 stimulation, which enhanced its conversion to P60. cAMP generation also activated CREB3L2, but independently of glucose. Deletion of CREB3L2 inhibited GSIS ex vivo and, following a high-fat diet (HFD), impaired glucose tolerance and insulin secretion in vivo. RNAseq revealed that CREB3L2 regulated genes controlling trafficking to-and-from the Golgi, as well as a broader cohort associated with β-cell compensation during a HFD. Although post-Golgi trafficking appeared intact, knockdown of CREB3L2 impaired the generation of both nascent ISGs and proinsulin condensates in the Golgi, implying a defect in ER export of proinsulin and/or its processing in the Golgi. CONCLUSION The stimulation of CREB3L2 by glucose defines a novel, rapid and direct mechanism for co-ordinating the synthesis, packaging and storage of insulin, thereby minimizing ER overload and optimizing β-cell function under conditions of high secretory demand. Upregulation of CREB3L2 also potentially contributes to the benefits of GLP1 agonism and might in itself constitute a novel means of treating β-cell failure.
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Affiliation(s)
- Nancy Sue
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Le May Thai
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Atsushi Saito
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, Department of Internal Medicine, University of Iowa, Iowa City, IA 52246, USA
| | - Ashleigh M Fordham
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Chenxu Yan
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Aimee Davenport
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Jiang Tao
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Mohammed Bensellam
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - James Cantley
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia
| | - Yan-Chuan Shi
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, Australia
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, Department of Internal Medicine, University of Iowa, Iowa City, IA 52246, USA
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Trevor J Biden
- Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, The University of New South Wales, Sydney, Australia.
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11
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Walker JT, Saunders DC, Rai V, Chen HH, Orchard P, Dai C, Pettway YD, Hopkirk AL, Reihsmann CV, Tao Y, Fan S, Shrestha S, Varshney A, Petty LE, Wright JJ, Ventresca C, Agarwala S, Aramandla R, Poffenberger G, Jenkins R, Mei S, Hart NJ, Phillips S, Kang H, Greiner DL, Shultz LD, Bottino R, Liu J, Below JE, Parker SCJ, Powers AC, Brissova M. Genetic risk converges on regulatory networks mediating early type 2 diabetes. Nature 2023; 624:621-629. [PMID: 38049589 PMCID: PMC11374460 DOI: 10.1038/s41586-023-06693-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 09/28/2023] [Indexed: 12/06/2023]
Abstract
Type 2 diabetes mellitus (T2D), a major cause of worldwide morbidity and mortality, is characterized by dysfunction of insulin-producing pancreatic islet β cells1,2. T2D genome-wide association studies (GWAS) have identified hundreds of signals in non-coding and β cell regulatory genomic regions, but deciphering their biological mechanisms remains challenging3-5. Here, to identify early disease-driving events, we performed traditional and multiplexed pancreatic tissue imaging, sorted-islet cell transcriptomics and islet functional analysis of early-stage T2D and control donors. By integrating diverse modalities, we show that early-stage T2D is characterized by β cell-intrinsic defects that can be proportioned into gene regulatory modules with enrichment in signals of genetic risk. After identifying the β cell hub gene and transcription factor RFX6 within one such module, we demonstrated multiple layers of genetic risk that converge on an RFX6-mediated network to reduce insulin secretion by β cells. RFX6 perturbation in primary human islet cells alters β cell chromatin architecture at regions enriched for T2D GWAS signals, and population-scale genetic analyses causally link genetically predicted reduced RFX6 expression with increased T2D risk. Understanding the molecular mechanisms of complex, systemic diseases necessitates integration of signals from multiple molecules, cells, organs and individuals, and thus we anticipate that this approach will be a useful template to identify and validate key regulatory networks and master hub genes for other diseases or traits using GWAS data.
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Affiliation(s)
- John T Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Diane C Saunders
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Vivek Rai
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Hung-Hsin Chen
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Peter Orchard
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Chunhua Dai
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yasminye D Pettway
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Alexander L Hopkirk
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Conrad V Reihsmann
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yicheng Tao
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Simin Fan
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Shristi Shrestha
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Arushi Varshney
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Lauren E Petty
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jordan J Wright
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Christa Ventresca
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Samir Agarwala
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Radhika Aramandla
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Greg Poffenberger
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Regina Jenkins
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Shaojun Mei
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Nathaniel J Hart
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sharon Phillips
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Hakmook Kang
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Dale L Greiner
- Department of Molecular Medicine, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Rita Bottino
- Imagine Pharma, Devon, PA, USA
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
| | - Jie Liu
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Jennifer E Below
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephen C J Parker
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA.
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA.
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA.
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- VA Tennessee Valley Healthcare System, Nashville, TN, USA.
| | - Marcela Brissova
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
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12
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Stojanovic J, Andjelic-Jelic M, Vuksanovic M, Marjanovic-Petkovic M, Jojic B, Stojanovic M, Beljic-Zivkovic T. The effects of early short-term insulin treatment vs. glimepiride on beta cell function in newly diagnosed type 2 diabetes with HbA1c above 9. Turk J Med Sci 2023; 53:552-562. [PMID: 37476884 PMCID: PMC10387975 DOI: 10.55730/1300-0144.5616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 01/20/2023] [Indexed: 07/22/2023] Open
Abstract
BACKGROUND Type 2 diabetes mellitus (T2D) is a complex metabolic impairment. Beta cell (BC) failure is the most challenging among its pathogenetic mechanisms. Recognizing reversible contributors to BC failure could guide individualized approach to early T2D treatment. The aim of this study was to compare early short-term insulin treatment vs. glimepiride, both added to metformin, on BC function, glycemic and lipid control, during 12-month follow-up. METHODS Eighty newly diagnosed T2D patients, 30-65 years of age, presenting with HbA1c ≥ 9% were enrolled in the study. They were randomly assigned to single-month initial insulin therapy (INS) added to metformin, or to glimepiride and metformin (OAD) as only treatment. Subjects assigned to initial insulin intervention were thereafter switched to OAD. C-peptide (C-Pep) was analyzed at baseline and 2 hours after standardized test meal (STM). All subjects were STM-retested after 3 and 12 months. HbA1c, serum lipids, BMI, HOMA IR, and HOMA B were assessed over follow-up. RESULTS HbA1c was lower in INS vs OAD at 3-months: 6.26 ± 0.18% vs 6.78 ± 0.10% (p = 0.016), remaining so by 12 months (p =0.056). BMI-adjusted ΔC-Pep was greater in INS vs. OAD at 3 months (4.60 ± 0.59 vs. 3.21 ± 0.34 m2 /kg; p = 0.044), persisting by 12months (4.57 ± 0.56 vs. 3.04 ± 0.34 m2/kg; p = 0.023). Average ΔC-Pep improvement from recruitment to 3 months was 100.8% in INS,vs. 51.3% in OAD. Prevalence of STM-ΔC-Pep response greater than 2.4 ng/mL had risen 3.2-fold by 12 months in the INS, vs. 2.4-fold only in the OAD group (p = 0.018). DISCUSSION Early short-term insulin intervention in newly diagnosed T2D improves beta cell function more than glimepiride, both added to metformin, resulting in a superior and longer lasting glycemic and lipid control.
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Affiliation(s)
- Jelena Stojanovic
- Division of Endocrinology, Diabetes and Metabolic Disorders, Department of Internal Medicine, Zvezdara University Medical Center, Belgrade, Serbia
| | - Marina Andjelic-Jelic
- Department of Internal Medicine, Faculty of Dental Medicine, University of Belgrade, Belgrade, Serbia ; Division of Endocrinology, Diabetes and Metabolic Disorders, Department of Internal Medicine,Zvezdara University Medical Center, Belgrade, Serbia
| | - Miljanka Vuksanovic
- Department of Internal Medicine, Medical Faculty,University of Belgrade, Belgrade, Serbia ; Division of Endocrinology, Diabetes and Metabolic Disorders, Department of Internal Medicine,Zvezdara University Medical Center, Belgrade, Serbia
| | - Milica Marjanovic-Petkovic
- Department of Internal Medicine, Medical Faculty,University of Belgrade, Belgrade, Serbia; Division of Endocrinology, Diabetes and Metabolic Disorders, Department of Internal Medicine,Zvezdara University Medical Center, Belgrade, Serbia
| | - Biljana Jojic
- Division of Endocrinology, Diabetes and Metabolic Disorders, Department of Internal Medicine,Zvezdara University Medical Center, Belgrade, Serbia
| | - Marko Stojanovic
- Department of Internal Medicine, Medical Faculty,University of Belgrade, Belgrade, Serbia ; Department of Neuroendocrinology, Clinic for Endocrinology, Diabetes and Metabolic Diseases,University Clinical Center of Serbia, Belgrade, Serbia
| | - Teodora Beljic-Zivkovic
- Department of Internal Medicine, Medical Faculty,University of Belgrade, Belgrade, Serbia;Division of Endocrinology, Diabetes and Metabolic Disorders, Department of Internal Medicine,Zvezdara University Medical Center, Belgrade, Serbia
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13
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Boyer CK, Bauchle CJ, Zhang J, Wang Y, Stephens SB. Synchronized proinsulin trafficking reveals delayed Golgi export accompanies β-cell secretory dysfunction in rodent models of hyperglycemia. Sci Rep 2023; 13:5218. [PMID: 36997560 PMCID: PMC10063606 DOI: 10.1038/s41598-023-32322-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 03/25/2023] [Indexed: 04/03/2023] Open
Abstract
The pancreatic islet β-cell's preference for release of newly synthesized insulin requires careful coordination of insulin exocytosis with sufficient insulin granule production to ensure that insulin stores exceed peripheral demands for glucose homeostasis. Thus, the cellular mechanisms regulating insulin granule production are critical to maintaining β-cell function. In this report, we utilized the synchronous protein trafficking system, RUSH, in primary β-cells to evaluate proinsulin transit through the secretory pathway leading to insulin granule formation. We demonstrate that the trafficking, processing, and secretion of the proinsulin RUSH reporter, proCpepRUSH, are consistent with current models of insulin maturation and release. Using both a rodent dietary and genetic model of hyperglycemia and β-cell dysfunction, we show that proinsulin trafficking is impeded at the Golgi and coincides with the decreased appearance of nascent insulin granules at the plasma membrane. Ultrastructural analysis of β-cells from diabetic leptin receptor deficient mice revealed gross morphological changes in Golgi structure, including shortened and swollen cisternae, and partial Golgi vesiculation, which are consistent with defects in secretory protein export. Collectively, this work highlights the utility of the proCpepRUSH reporter in studying proinsulin trafficking dynamics and suggests that altered Golgi export function contributes to β-cell secretory defects in the pathogenesis of Type 2 diabetes.
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Affiliation(s)
- Cierra K Boyer
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52246, USA
| | - Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52246, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA, 52246, USA
| | - Jianchao Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA, 52246, USA.
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA, 52246, USA.
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14
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Dalle S, Abderrahmani A, Renard E. Pharmacological inhibitors of β-cell dysfunction and death as therapeutics for diabetes. Front Endocrinol (Lausanne) 2023; 14:1076343. [PMID: 37008937 PMCID: PMC10050720 DOI: 10.3389/fendo.2023.1076343] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 02/20/2023] [Indexed: 03/17/2023] Open
Abstract
More than 500 million adults suffer from diabetes worldwide, and this number is constantly increasing. Diabetes causes 5 million deaths per year and huge healthcare costs per year. β-cell death is the major cause of type 1 diabetes. β-cell secretory dysfunction plays a key role in the development of type 2 diabetes. A loss of β-cell mass due to apoptotic death has also been proposed as critical for the pathogenesis of type 2 diabetes. Death of β-cells is caused by multiple factors including pro-inflammatory cytokines, chronic hyperglycemia (glucotoxicity), certain fatty acids at high concentrations (lipotoxicity), reactive oxygen species, endoplasmic reticulum stress, and islet amyloid deposits. Unfortunately, none of the currently available antidiabetic drugs favor the maintenance of endogenous β-cell functional mass, indicating an unmet medical need. Here, we comprehensively review over the last ten years the investigation and identification of molecules of pharmacological interest for protecting β-cells against dysfunction and apoptotic death which could pave the way for the development of innovative therapies for diabetes.
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Affiliation(s)
- Stéphane Dalle
- Institut de Génomique Fonctionnelle, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Montpellier, France
| | - Amar Abderrahmani
- Université Lille, Centre National de la Recherche Scientifique (CNRS), Centrale Lille, Polytechnique Hauts-de-France, UMR 8520, IEMN, Lille, France
| | - Eric Renard
- Institut de Génomique Fonctionnelle, Université de Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Montpellier, France
- Laboratoire de Thérapie Cellulaire du Diabète, Centre Hospitalier Universitaire, Montpellier, France
- Département d’Endocrinologie, Diabètologie, Centre Hospitalier Universitaire, Montpellier, France
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15
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Lokman EF, Bugam SH, Ibrahim AS, Yunus N, Mansor F, Balasubramaniam V, Mohamad KM, Md Lazim R, Awang Seruji AZR. Postprandial glucose-lowering effects by sago ( Metroxylon sagu Rottb.) resistant starch in spontaneously type 2 diabetes, Goto-Kakizaki rat. Nutr Health 2023:2601060231152060. [PMID: 36755355 DOI: 10.1177/02601060231152060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Introduction: The beneficial effects of resistant starch (RS) consumption on health in terms of reducing postprandial hyperglycaemia are evident. However, the potential of local Sarawak sago RS in regulating glucose has not been extensively studied. Objectives: This study aims to identify glucose-lowering effects of Sarawak sago RS, namely native (RS2) and chemically modified (RS4). Methodology: An oral glucose tolerance test (OGTT) was performed before and after 1 month treatment with sago RS2 and RS4 in spontaneously type 2 diabetes (T2D), Goto-Kakizaki (GK) rat. The mechanisms involved were further explored by screening the in vitro inhibitory activities of α-glucosidase and dipeptidyl peptidase (DPP)-IV. Histopathology examination for pancreas, kidney and liver tissues was done in response to sago RS intake using haematoxylin and eosin (H&E) staining. Results and discussion: The incremental area under the curve (iAUC) for blood glucose in RS-treated groups was decreased and significant in RS2-treated group (p < 0.05). Improved iAUC for insulin and higher glucagon-like peptide (GLP-1) levels were observed in all RS-treated groups (p < 0.05). Both sago RS may have potential roles in regulating glucose via α- glucosidase and DPP-IV inhibitory activities by reducing intestinal glucose absorption. For histopathology, although insignificant, sago RS2 and RS4 attenuated lesion scores of pancreatic tissue whereas the liver and kidney tissues significantly showed lesser lesion scores compared to the control diabetic group suggesting the potential of RS in reducing cell degeneration. Conclusion: Findings of this study indicates that RS2 showed greater glucose-lowering effect when compared to RS4, thus the therapeutic potential in the T2D management should be further explored.
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Affiliation(s)
- Ezarul Faradianna Lokman
- Endocrine and Metabolic Unit, Nutrition, Metabolism and Cardiovascular Research Centre (NMCRC), Institute for Medical Research, National Institutes of Health, Selangor, Malaysia
| | - Sal Hazreen Bugam
- Downstream Technology Division, CRAUN Research Sdn. Bhd., Sarawak, Malaysia
| | | | - Nurleyna Yunus
- Downstream Technology Division, CRAUN Research Sdn. Bhd., Sarawak, Malaysia
| | - Fazliana Mansor
- Endocrine and Metabolic Unit, Nutrition, Metabolism and Cardiovascular Research Centre (NMCRC), Institute for Medical Research, National Institutes of Health, Selangor, Malaysia
| | - Vimala Balasubramaniam
- Nutrition Unit, Nutrition, Metabolism and Cardiovascular Research Centre (NMCRC), Institute for Medical Research, National Institutes of Health, Selangor, Malaysia
| | - Khairul Mirza Mohamad
- Endocrine and Metabolic Unit, Nutrition, Metabolism and Cardiovascular Research Centre (NMCRC), Institute for Medical Research, National Institutes of Health, Selangor, Malaysia
| | - Rabizah Md Lazim
- Endocrine and Metabolic Unit, Nutrition, Metabolism and Cardiovascular Research Centre (NMCRC), Institute for Medical Research, National Institutes of Health, Selangor, Malaysia
- Downstream Technology Division, CRAUN Research Sdn. Bhd., Sarawak, Malaysia
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Xu L, Jois S, Cui H. Metformin and Gegen Qinlian Decoction boost islet α-cell proliferation of the STZ induced diabetic rats. BMC Complement Med Ther 2022; 22:193. [PMID: 35858880 PMCID: PMC9301855 DOI: 10.1186/s12906-022-03674-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 07/14/2022] [Indexed: 12/02/2022] Open
Abstract
Background The traditional Chinese medicine Gegen Qinlian Decoction (GQD), as well as metformin, had been reported with anti-diabetic effects in clinical practice. Objective To verify whether these two medicines effectively ameliorate hyperglycemia caused by deficiency of islet β-cell mass which occurs in both type 1 and type 2 diabetes. Methods SD rats were injected with a single dose of STZ (55 mg/kg) to induce β-cell destruction. The rats were then divided into control, diabetes, GQD and metformin group. GQD and metformin groups were administered with GQD extract or metformin for 6 weeks. The islet α-cell or β-cell mass changes were tested by immunohistochemical and immunofluorescent staining. The potential targets and mechanisms of GQD and metformin on cell proliferation were tested using in silico network pharmacology. Real-time PCR was performed to test the expression of islet cells related genes and targets related genes. Results Both GQD and metformin did not significantly reduce the FBG level caused by β-cell mass reduction, but alleviated liver and pancreas histopathology. Both GQD and metformin did not change the insulin positive cell mass but increased α-cell proliferation of the diabetic rats. Gene expression analysis showed that GQD and metformin significantly increased the targets gene cyclin-dependent kinase 4 (Cdk4) and insulin receptor substrate (Irs1) level. Conclusion This research indicates that GQD and metformin significantly increased the α-cell proliferation of β-cell deficiency induced diabetic rats by restoring Cdk4 and Irs1 gene expression.
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17
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Akalestou E, Lopez-Noriega L, Christakis I, Hu M, Miras AD, Leclerc I, Rutter GA. Vertical sleeve gastrectomy normalizes circulating glucocorticoid levels and lowers glucocorticoid action tissue-selectively in mice. Front Endocrinol (Lausanne) 2022; 13:1020576. [PMID: 36246869 PMCID: PMC9556837 DOI: 10.3389/fendo.2022.1020576] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/08/2022] [Indexed: 11/13/2022] Open
Abstract
Objectives Glucocorticoids produced by the adrenal cortex are essential for the maintenance of metabolic homeostasis. Glucocorticoid activation is catalysed by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). Excess glucocorticoids are associated with insulin resistance and hyperglycaemia. A small number of studies have demonstrated effects on glucocorticoid metabolism of bariatric surgery, a group of gastrointestinal procedures known to improve insulin sensitivity and secretion, which were assumed to result from weight loss. In this study, we hypothesize that a reduction in glucocorticoid action following bariatric surgery contributes to the widely observed euglycemic effects of the treatment. Methods Glucose and insulin tolerance tests were performed at ten weeks post operatively and circulating corticosterone was measured. Liver and adipose tissues were harvested from fed mice and 11β-HSD1 levels were measured by quantitative RT-PCR or Western (immuno-) blotting, respectively. 11β-HSD1 null mice (Hsd11b1 -/-) were generated using CRISPR/Cas9 genome editing. Wild type and littermate Hsd11b1 -/- mice underwent Vertical Sleeve Gastrectomy (VSG) or sham surgery. Results Under the conditions used, no differences in weight loss were observed between VSG treated and sham operated mice. However, both lean and obese WT VSG mice displayed significantly improved glucose clearance and insulin sensitivity. Remarkably, VSG restored physiological corticosterone production in HFD mice and reduced 11β-HSD1 expression in liver and adipose tissue post-surgery. Elimination of the 11β-HSD1/Hsd11b1 gene by CRISPR/Cas9 mimicked the effects of VSG on body weight and tolerance to 1g/kg glucose challenge. However, at higher glucose loads, the euglycemic effect of VSG was superior to Hsd11b1 elimination. Conclusions Bariatric surgery improves insulin sensitivity and reduces glucocorticoid activation at the tissular level, under physiological and pathophysiological (obesity) conditions, irrespective of weight loss. These findings point towards a physiologically relevant gut-glucocorticoid axis, and suggest that lowered glucocorticoid exposure may represent an additional contribution to the health benefits of bariatric surgery.
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Affiliation(s)
- Elina Akalestou
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Livia Lopez-Noriega
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Ioannis Christakis
- Endocrine and General Surgery, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Ming Hu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Alexander D. Miras
- Section of Investigative Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- Centre de Recherches du CHUM, University of Montreal, Montreal, QC, Canada
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- Centre de Recherches du CHUM, University of Montreal, Montreal, QC, Canada
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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18
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Rohli KE, Boyer CK, Bearrows SC, Moyer MR, Elison WS, Bauchle CJ, Blom SE, Zhang J, Wang Y, Stephens SB. ER Redox Homeostasis Regulates Proinsulin Trafficking and Insulin Granule Formation in the Pancreatic Islet β-Cell. FUNCTION 2022; 3:zqac051. [PMID: 36325514 PMCID: PMC9614934 DOI: 10.1093/function/zqac051] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/11/2022] [Accepted: 09/21/2022] [Indexed: 01/07/2023] Open
Abstract
Defects in the pancreatic β-cell's secretion system are well-described in type 2 diabetes (T2D) and include impaired proinsulin processing and a deficit in mature insulin-containing secretory granules; however, the cellular mechanisms underlying these defects remain poorly understood. To address this, we used an in situ fluorescent pulse-chase strategy to study proinsulin trafficking. We show that insulin granule formation and the appearance of nascent granules at the plasma membrane are decreased in rodent and cell culture models of prediabetes and hyperglycemia. Moreover, we link the defect in insulin granule formation to an early trafficking delay in endoplasmic reticulum (ER) export of proinsulin, which is independent of overt ER stress. Using a ratiometric redox sensor, we show that the ER becomes hyperoxidized in β-cells from a dietary model of rodent prediabetes and that addition of reducing equivalents restores ER export of proinsulin and insulin granule formation and partially restores β-cell function. Together, these data identify a critical role for the regulation of ER redox homeostasis in proinsulin trafficking and suggest that alterations in ER redox poise directly contribute to the decline in insulin granule production in T2D. This model highlights a critical link between alterations in ER redox and ER function with defects in proinsulin trafficking in T2D. Hyperoxidation of the ER lumen, shown as hydrogen peroxide, impairs proinsulin folding and disulfide bond formation that prevents efficient exit of proinsulin from the ER to the Golgi. This trafficking defect limits available proinsulin for the formation of insulin secretory granules during the development of T2D.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Shelby C Bearrows
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Marshall R Moyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Weston S Elison
- Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Jianchao Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48103, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48103, USA
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48103, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
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19
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Targeting Ceramides and Adiponectin Receptors in the Islet of Langerhans for Treating Diabetes. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27186117. [PMID: 36144859 PMCID: PMC9502927 DOI: 10.3390/molecules27186117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 11/17/2022]
Abstract
Ceramides belong to the sphingolipid family and represent the central hub of the sphingolipid network. In obesity, oversupply of saturated fatty acids including palmitate raises ceramide levels which can be detrimental to cells. Elevated ceramides can cause insulin resistance, endoplasmic reticulum stress, and mitochondrial dysfunction. Studies over the last few decades have highlighted the role played by ceramides in pancreatic islet β-cell apoptosis, especially under glucolipotoxic and inflammatory conditions. This review focuses on ceramides and adiponectin receptor signaling, summarizing recent advancements in our understanding of their roles in islet β-cells and the discovery of zinc-dependent lipid hydrolase (ceramidase) activity of adiponectin receptors. The therapeutic potential of targeting these events to prevent islet β-cell loss for treating diabetes is discussed.
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20
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McDonald S, Ray P, Bunn RC, Fowlkes JL, Thrailkill KM, Popescu I. Heterogeneity and altered β-cell identity in the TallyHo model of early-onset type 2 diabetes. Acta Histochem 2022; 124:151940. [PMID: 35969910 DOI: 10.1016/j.acthis.2022.151940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 11/01/2022]
Abstract
A primary underlying defect makes β-cells "susceptible" to no longer compensate for the peripheral insulin resistance and to trigger the onset of type 2 diabetes (T2D). New evidence suggests that in T2D, β-cells are not destroyed but experience a loss of identity, reverting to a progenitor-like state and largely losing the ability to sense glucose and produce insulin. We assessed (using fluorescence microscopy and histomorphometry correlated with the glycaemic status) the main β-cell identity modifications as diabetes progresses in the TallyHo/JngJ (TH) male mice, a polygenic model of spontaneous T2D, akin to the human phenotype. We found that: 1) conversion to overt diabetes is paralleled by a progressive reduction of insulin-expressing cells and expansion of a glucagon-positive population, together with alteration of islet size and shape; 2) the β-cell population is highly heterogeneous in terms of insulin content and specific transcription factors like PDX1 and NKX6.1, that are gradually lost during diabetes progression; 3) GLUT2 expression is altered early and strongly reduced at late stages of diabetes; 4) an endocrine developmental program dependent on NGN3-expressing progenitors is revived when hyperglycaemia becomes severe; and 5) the re-expression of the EMT-associated factor vimentin occurs as diabetes worsens, representing a possible regenerative response to β-cell loss. Based on these results, we formulated additional hypotheses for the β-cell identity alteration in the TH model, together with several limitations of the study, that constitute future research directions.
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Affiliation(s)
- Sarah McDonald
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA
| | - Phil Ray
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - Robert C Bunn
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - John L Fowlkes
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - Kathryn M Thrailkill
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA; Department of Pediatric Endocrinology, University of Kentucky, College of Medicine, 2195 Harrodsburg Rd., Lexington, KY 40504, USA
| | - Iuliana Popescu
- Barnstable Brown Diabetes Center, University of Kentucky, College of Medicine, 900S. Limestone, CTW 469, Lexington, KY 40536, USA.
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21
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Akalestou E, Lopez-Noriega L, Tough IR, Hu M, Leclerc I, Cox HM, Rutter GA. Vertical Sleeve Gastrectomy Lowers SGLT2/Slc5a2 Expression in the Mouse Kidney. Diabetes 2022; 71:1623-1635. [PMID: 35594379 DOI: 10.2337/db21-0768] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 05/02/2022] [Indexed: 11/13/2022]
Abstract
Bariatric surgery improves glucose homeostasis, but the underlying mechanisms are not fully elucidated. Here, we show that the expression of sodium-glucose cotransporter 2 (SGLT2/Slc5a2) is reduced in the kidney of lean and obese mice following vertical sleeve gastrectomy (VSG). Indicating an important contribution of altered cotransporter expression to the impact of surgery, inactivation of the SGLT2/Slc5a2 gene by clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 attenuated the effects of VSG, with glucose excursions following intraperitoneal injection lowered by ∼30% in wild-type mice but by ∼20% in SGLT2-null animals. The effects of the SGLT2 inhibitor dapaglifozin were similarly blunted by surgery. Unexpectedly, effects of dapaglifozin were still observed in SGLT2-null mice, consistent with the existence of metabolically beneficial off-target effects of SGLT2 inhibitors. Thus, we describe a new mechanism involved in mediating the glucose-lowering effects of bariatric surgery.
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Affiliation(s)
- Elina Akalestou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, U.K
| | - Livia Lopez-Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, U.K
| | - Iain R Tough
- Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London, U.K
| | - Ming Hu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, U.K
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, U.K
- Centre de Recherches du Centre hospitalier de l'Université de Montréal (CHUM), University of Montreal, Montreal, Quebec, Canada
| | - Helen M Cox
- Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London, U.K
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, U.K
- Centre de Recherches du Centre hospitalier de l'Université de Montréal (CHUM), University of Montreal, Montreal, Quebec, Canada
- Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
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22
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Cargo receptor Surf4 regulates endoplasmic reticulum export of proinsulin in pancreatic β-cells. Commun Biol 2022; 5:458. [PMID: 35562580 PMCID: PMC9106718 DOI: 10.1038/s42003-022-03417-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 04/26/2022] [Indexed: 11/08/2022] Open
Abstract
Insulin is an essential peptide hormone that maintains blood glucose levels. Although the mechanisms underlying insulin exocytosis have been investigated, the mechanism of proinsulin export from the endoplasmic reticulum (ER) remains unclear. Here, we demonstrated that Surf4, a cargo receptor homolog, regulates the ER export of proinsulin via its recruitment to ER exit sites (ERES). Under high-glucose conditions, Surf4 expression was upregulated, and Surf4 proteins mainly localized to the ER at a steady state and accumulated in the ERES, along with proinsulin in rat insulinoma INS-1 cells. Surf4-knockdown resulted in proinsulin retention in the ER and decreased the levels of mature insulin in secretory granules, thereby significantly reducing insulin secretion. Surf4 forms an oligomer and can physically interact with proinsulin and Sec12, essential for COPII vesicle formation. Our findings suggest that Surf4 interacts with proinsulin and delivers it into COPII vesicles for ER export in co-operation with Sec12 and COPII.
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23
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Gang N, Van Allen K, Villeneuve PJ, MacDonald H, Bruin JE. Sex-specific Associations Between Type 2 Diabetes Incidence and Exposure to Dioxin and Dioxin-like Pollutants: A Meta-analysis. FRONTIERS IN TOXICOLOGY 2022; 3:685840. [PMID: 35295132 PMCID: PMC8915902 DOI: 10.3389/ftox.2021.685840] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 12/14/2021] [Indexed: 01/09/2023] Open
Abstract
The potential for persistent organic pollutants (POPs), including dioxins and dioxin-like polychlorinated biphenyls (DL-PCBs), to increase the risk of incident diabetes in adults has been extensively studied. However, there is substantial variability in the reported associations both between and within studies. Emerging data from rodent studies suggest that dioxin disrupts glucose homeostasis in a sex-specific manner. Thus, we performed a review and meta-analysis of relevant epidemiological studies to investigate sex differences in associations between dioxin or DL-PCB exposure and type 2 diabetes incidence. Articles that met our selection criteria (n = 81) were organized into the following subcategories: data stratified by sex (n = 13), unstratified data (n = 45), and data from only 1 sex (n = 13 male, n = 10 female). We also considered whether exposure occurred either abruptly at high concentrations through a contamination event (“disaster exposure”) or chronically at low concentrations (“non-disaster exposure”). There were 8 studies that compared associations between dioxin/DL-PCB exposure and diabetes risk in males versus females within the same population. When all sex-stratified or single-sex studies were considered in the meta-analysis (n = 18), the summary relative risk (RR) for incident diabetes among those exposed relative to reference populations was 1.78 (95% CI = 1.37–2.31) and 1.95 (95% CI = 1.56–2.43) for female and males, respectively. However, when we restricted the meta-analysis to disaster-exposed populations, the RR was higher in females than males (2.86 versus 1.59, respectively). In contrast, in non-disaster exposed populations the RR for females was lower than males (1.40 and 2.02, respectively). Our meta-analysis suggests that there are sex differences in the associations between dioxin/DL-PCBs exposure and incident diabetes, and that the mode of exposure modifies these differences.
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Affiliation(s)
- Noa Gang
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Kyle Van Allen
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
| | - Paul J. Villeneuve
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
- Department of Public Health Sciences, Queen’s University, Kingston, ON, Canada
| | - Heather MacDonald
- Health and Biosciences Librarian, MacOdrum Library, Carleton University, Ottawa, ON, Canada
| | - Jennifer E. Bruin
- Department of Biology and Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
- *Correspondence: Jennifer E. Bruin,
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24
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Rohli KE, Boyer CK, Blom SE, Stephens SB. Nutrient Regulation of Pancreatic Islet β-Cell Secretory Capacity and Insulin Production. Biomolecules 2022; 12:335. [PMID: 35204835 PMCID: PMC8869698 DOI: 10.3390/biom12020335] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 01/27/2023] Open
Abstract
Pancreatic islet β-cells exhibit tremendous plasticity for secretory adaptations that coordinate insulin production and release with nutritional demands. This essential feature of the β-cell can allow for compensatory changes that increase secretory output to overcome insulin resistance early in Type 2 diabetes (T2D). Nutrient-stimulated increases in proinsulin biosynthesis may initiate this β-cell adaptive compensation; however, the molecular regulators of secretory expansion that accommodate the increased biosynthetic burden of packaging and producing additional insulin granules, such as enhanced ER and Golgi functions, remain poorly defined. As these adaptive mechanisms fail and T2D progresses, the β-cell succumbs to metabolic defects resulting in alterations to glucose metabolism and a decline in nutrient-regulated secretory functions, including impaired proinsulin processing and a deficit in mature insulin-containing secretory granules. In this review, we will discuss how the adaptative plasticity of the pancreatic islet β-cell's secretory program allows insulin production to be carefully matched with nutrient availability and peripheral cues for insulin signaling. Furthermore, we will highlight potential defects in the secretory pathway that limit or delay insulin granule biosynthesis, which may contribute to the decline in β-cell function during the pathogenesis of T2D.
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Affiliation(s)
- Kristen E. Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K. Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E. Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Samuel B. Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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25
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Oh KK. A network pharmacology study to investigate bioactive compounds and signaling pathways of garlic (Allium sativum L.) husk against type 2 diabetes mellitus. J Food Biochem 2022; 46:e14106. [PMID: 35137431 DOI: 10.1111/jfbc.14106] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/13/2021] [Accepted: 01/20/2022] [Indexed: 12/24/2022]
Abstract
During garlic harvest, much husk has been generated, nearly all husk is discarded as unnecessary by-products. However, in Korean folk remedies, Allium sativum L. husk (ASLH) extracts have been used as a reliever against type 2 diabetes mellitus (T2DM). Currently, its significant mechanisms against T2DM remain unclear. Thus, the aim of this study is to investigate the characteristics of its key signaling pathways, targets, and compounds. The compounds in ASLH were analyzed by gas chromatography-mass spectrum (GC-MS) and confirmed drug-like compounds (DLCs) in silico. Then, protein-protein interaction (PPI) networks and signaling pathways, targets, compounds are constructed, visualized by using RStudio. Finally, we performed a molecular docking test (MDT) to identify the key mechanism(s), target(s), and compound(s) of ASLH on T2DM. A total of 23 compounds in ASLH were identified by GC-MS, and all compounds were accepted by Lipinski's rule. The 23 compounds were associated with 521 targets and retrieved 4,736 T2DM-related targets by Online Mendelian Inheritance in Man (OMIM) and DisGeNET. The final overlapping 87 targets were obtained between compounds-targets and T2DM-related targets. The number of 13 signaling pathways, 33 targets, and 19 compounds of ASLH were associated with T2DM. In parallel, MDT revealed four potential compounds: (1) 9-hexacosene, (2) 2-(([2-ethylhexyl]oxy)carbonyl)benzoic acid, (3) clionasterol, (4) 4-methyl-2-phenylpyrimidine on PPAR signaling pathway. Overall, the four compounds from ASLH might show an anti-T2DM synergistic effect by activating the PPAR signaling pathway or inactivating the phospholipase D signaling pathway. In this study, we suggest that ASLH might be considered a health-promising resource from both nutraceutical and pharmaceutical perspectives. PRACTICAL APPLICATIONS: Allium sativum L. husk (ASLH) has been regarded as wastes that come from garlic (Allium sativum L.). During the harvesting period of garlic, a considerable amount of ASLH is a severe problem in farm communities. Particularly, garlic bioactive compounds are well documented including organosulfur compounds. Conversely, at present, no information is available on chemical compounds of ASLH to use in health industries. Taking this matter into consideration, our analysis approach was to select drug-like compounds (DLCs) from ASLH via GC-MS, thereby we can explore the compounds with high cell permeability. The screened compounds can be used as nutraceutical or medicinal or even cosmetical resources. In this study, we described the significant compounds via the network pharmacology concept to uncover the pharmaceutical mechanism(s) of ASLH against T2DM. Eventually, this work provides nutraceutical or medicinal value of ASLH and suggests that ASLH might be used as an upcycling resource to relieve T2DM.
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Affiliation(s)
- Ki Kwang Oh
- Department of Bio-Health Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, South Korea
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26
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Shcheglova E, Blaszczyk K, Borowiak M. Mitogen Synergy: An Emerging Route to Boosting Human Beta Cell Proliferation. Front Cell Dev Biol 2022; 9:734597. [PMID: 35155441 PMCID: PMC8829426 DOI: 10.3389/fcell.2021.734597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/24/2021] [Indexed: 12/11/2022] Open
Abstract
Decreased number and function of beta cells are a key aspect of diabetes mellitus (diabetes), a disease that remains an onerous global health problem. Means of restoring beta cell mass are urgently being sought as a potential cure for diabetes. Several strategies, such as de novo beta cell derivation via pluripotent stem cell differentiation or mature somatic cell transdifferentiation, have yielded promising results. Beta cell expansion is another promising strategy, rendered challenging by the very low proliferative capacity of beta cells. Many effective mitogens have been identified in rodents, but the vast majority do not have similar mitogenic effects in human beta cells. Extensive research has led to the identification of several human beta cell mitogens, but their efficacy and specificity remain insufficient. An approach based on the simultaneous application of several mitogens has recently emerged and can yield human beta cell proliferation rates of up to 8%. Here, we discuss recent advances in restoration of the beta cell population, focusing on mitogen synergy, and the contribution of RNA-sequencing (RNA-seq) to accelerating the elucidation of signaling pathways in proliferating beta cells and the discovery of novel mitogens. Together, these approaches have taken beta cell research up a level, bringing us closer to a cure for diabetes.
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Affiliation(s)
- Ekaterina Shcheglova
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Katarzyna Blaszczyk
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Malgorzata Borowiak
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
- *Correspondence: Malgorzata Borowiak, ;
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27
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Brooks-Worrell B, Hampe CS, Hattery EG, Palomino B, Zangeneh SZ, Utzschneider K, Kahn SE, Larkin ME, Johnson ML, Mather KJ, Younes N, Rasouli N, Desouza C, Cohen RM, Park JY, Florez HJ, Valencia WM, Shojaie A, Palmer JP, Balasubramanyam A. Islet Autoimmunity is Highly Prevalent and Associated With Diminished β-Cell Function in Patients With Type 2 Diabetes in the Grade Study. Diabetes 2022; 71:db210590. [PMID: 35061024 PMCID: PMC9375448 DOI: 10.2337/db21-0590] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/08/2021] [Indexed: 11/13/2022]
Abstract
Islet autoimmunity may contribute to β-cell dysfunction in type 2 diabetes (T2D). Its prevalence and clinical significance have not been rigorously determined. In this ancillary study to the Glycemia Reduction Approaches in Diabetes-A Comparative Effectiveness (GRADE) Study, we investigated the prevalence of cellular and humoral islet autoimmunity in patients with T2D duration 4·0±3·0 y, HbA1c 7·5±0·5% on metformin alone. We measured T cell autoreactivity against islet proteins, islet autoantibodies against GAD65, IA2, ZnT8, and β-cell function. Cellular islet autoimmunity was present in 41·3%, humoral islet autoimmunity in 13·5%, and both in 5·3%. β-cell function calculated as iAUC-CG and ΔC-peptide(0- 30)/Δglucose(0-30) from an oral glucose tolerance test was lower among T cell-positives (T+) than T cell-negatives (T-) using two different adjustments for insulin sensitivity (iAUC-CG: 13·2% [95% CI 0·3, 24·4%] or 11·4% [95% CI 0·4, 21·2%] lower; ΔC-peptide(0-30)/Δglucose(0-30)) 19% [95% CI 3·1, 32·3%] or 17·7% [95% CI 2·6, 30·5%] lower). T+ patients had 17% higher HbA1c (95% CI 0·07, 0·28) and 7·7 mg/dL higher fasting plasma glucose levels (95% CI 0·2,15·3) than T- patients. We conclude that islet autoimmunity is much more prevalent in T2D patients than previously reported. T cell-mediated autoimmunity is associated with diminished β-cell function and worse glycemic control.
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Affiliation(s)
| | | | | | | | | | | | - Steven E. Kahn
- VA Puget Sound Health Care System, Seattle, WA
- University of Washington, Seattle, WA
| | | | | | | | - Naji Younes
- The Biostatistics Center, Department of Biostatistics and Bioinformatics, Milken Institute School of Public Health, The George Washington University, Rockville, MD
| | - Neda Rasouli
- University of Colorado School of Medicine, Aurora, CO
| | - Cyrus Desouza
- University of Nebraska and Omaha VA Medical Center, Omaha, NE
| | - Robert M. Cohen
- University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH
| | | | - Hermes J. Florez
- University of Miami, Miami, FL
- Medical University of South Carolina, Charleston, SC
| | | | | | | | - Jerry P. Palmer
- VA Puget Sound Health Care System, Seattle, WA
- University of Washington, Seattle, WA
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Lu J, Tian X, Tang D, Zhou X, Xu Z, Ding J, Wang T, Yu Q, Ding J. In vitro study of the drug-drug interaction potential of cetagliptin and clinical study of pharmacokinetic interaction of cetagliptin and metformin in healthy volunteers. Xenobiotica 2021; 51:1122-1131. [PMID: 34329567 DOI: 10.1080/00498254.2021.1963010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 07/28/2021] [Accepted: 07/28/2021] [Indexed: 12/20/2022]
Abstract
Cetagliptin is an oral, potent, and newly developed selective inhibitor of dipeptidyl peptidase-4 (DPP-4). We evaluated the in vitro drug-drug interaction (DDI) potential of cetagliptin, as well as the pharmacokinetics of cetagliptin and metformin and the interaction between cetagliptin and metformin.Cetagliptin did not inhibit CYP1A2, CYP2C8, CYP2B6, CYP2C9, CYP2C19, and CYP3A4, only has a moderate inhibitory effect on CYP2D6, and did not induce CYP1A2, CYP2B6, and CYP3A4. Plasma protein binding of cetagliptin didn't have species differences or concentration dependence. Cetagliptin was a substrate for P-glycoprotein (P-gp).The 34 healthy subjects enrolled were randomly divided into two sequences (A and B) with 17 subjects in each sequence. Coadministration with metformin had no effect on cetagliptin AUC0-120 (GMR, 99.25%; 90% CI, 95.96%-102.65%). There was a slightly increase in cetagliptin Cmax (GMR, 117.33%; 90% CI, 102.54%-134.25%). Coadministration with cetagliptin did not affect the metformin's AUC0-24 (GMR, 108.54%; 90% CI, 101.41%-116.17%) or Cmax (GMR, 97.67%; 90% CI, 90.96%-104.89%).Based on in vitro study results, cetagliptin is unlikely to cause CYP-mediated, clinically relevant DDI. Although the possibility of transporter-mediated, clinically relevant DDI cannot be ruled out, there is little or no risk of side effects. Coadministration of cetagliptin and metformin had no clinically meaningful effect on the pharmacokinetics of each drug. There was no drug-drug interaction between cetagliptin and metformin. Both monotherapies and combination therapy were well tolerated. No serious AEs and hypoglycaemia was reported.
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Affiliation(s)
- Jinmiao Lu
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
| | - Xusheng Tian
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Dong Tang
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Xinyi Zhou
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Zengyan Xu
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Juping Ding
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Tong Wang
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Qiang Yu
- CGeneTech (Suzhou, China) Co., Ltd, Suzhou, Jiangsu, China
| | - Jinsong Ding
- Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, China
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Pioglitazone Reverses Markers of Islet Beta-Cell De-Differentiation in db/db Mice While Modulating Expression of Genes Controlling Inflammation and Browning in White Adipose Tissue from Insulin-Resistant Mice and Humans. Biomedicines 2021; 9:biomedicines9091189. [PMID: 34572374 PMCID: PMC8470788 DOI: 10.3390/biomedicines9091189] [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: 06/25/2021] [Revised: 08/21/2021] [Accepted: 09/02/2021] [Indexed: 12/12/2022] Open
Abstract
Obesity, insulin resistance, and type 2 diabetes contribute to increased morbidity and mortality in humans. The db/db mouse is an important mouse model that displays many key features of the human disease. Herein, we used the drug pioglitazone, a thiazolidinedione with insulin-sensitizing properties, to investigate blood glucose levels, indicators of islet β-cell health and maturity, and gene expression in adipose tissue. Oral administration of pioglitazone lowered blood glucose levels in db/db mice with a corresponding increase in respiratory quotient, which indicates improved whole-body carbohydrate utilization. In addition, white adipose tissue from db/db mice and from humans treated with pioglitazone showed increased expression of glycerol kinase. Both db/db mice and humans given pioglitazone displayed increased expression of UCP-1, a marker typically associated with brown adipose tissue. Moreover, pancreatic β-cells from db/db mice treated with pioglitazone had greater expression of insulin and Nkx6.1 as well as reduced abundance of the de-differentiation marker Aldh1a3. Collectively, these findings indicate that four weeks of pioglitazone therapy improved overall metabolic health in db/db mice. Our data are consistent with published reports of human subjects administered pioglitazone and with analysis of human adipose tissue taken from subjects treated with pioglitazone. In conclusion, the current study provides evidence that pioglitazone restores key markers of metabolic health and also showcases the utility of the db/db mouse to understand mechanisms associated with human metabolic disease and interventions that provide therapeutic benefit.
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30
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Rezazadeh H, Sharifi MR, Soltani N. Insulin resistance and the role of gamma-aminobutyric acid. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2021; 26:39. [PMID: 34484371 PMCID: PMC8384006 DOI: 10.4103/jrms.jrms_374_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 12/09/2020] [Accepted: 02/02/2021] [Indexed: 12/17/2022]
Abstract
Insulin resistance (IR) is mentioned to be a disorder in insulin ability in insulin-target tissues. Skeletal muscle (SkM) and liver function are more affected by IR than other insulin target cells. SkM is the main site for the consumption of ingested glucose. An effective treatment for IR has two properties: An inhibition of β-cell death and a promotion of β-cell replication. Gamma-aminobutyric acid (GABA) can improve beta-cell mass and function. Multiple studies have shown that GABA decreases IR probably via increase in glucose transporter 4 (GLUT4) gene expression and prevention of gluconeogenesis pathway in the liver. This review focused on the general aspects of IR in skeletal muscle (SkM), liver; the cellular mechanism(s) lead to the development of IR in these organs, and the role of GABA to reduce insulin resistance.
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Affiliation(s)
- Hossein Rezazadeh
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| | - Mohammad Reza Sharifi
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
| | - Nepton Soltani
- Department of Physiology, School of Medicine, Isfahan University of Medical Science, Isfahan Iran
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31
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Brown MR, Holmes H, Rakshit K, Javeed N, Her TK, Stiller AA, Sen S, Shull GE, Prakash YS, Romero MF, Matveyenko AV. Electrogenic sodium bicarbonate cotransporter NBCe1 regulates pancreatic β cell function in type 2 diabetes. J Clin Invest 2021; 131:142365. [PMID: 34623331 DOI: 10.1172/jci142365] [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] [Received: 07/20/2020] [Accepted: 07/22/2021] [Indexed: 12/13/2022] Open
Abstract
Pancreatic β cell failure in type 2 diabetes mellitus (T2DM) is attributed to perturbations of the β cell's transcriptional landscape resulting in impaired glucose-stimulated insulin secretion. Recent studies identified SLC4A4 (a gene encoding an electrogenic Na+-coupled HCO3- cotransporter and intracellular pH regulator, NBCe1) as one of the misexpressed genes in β cells of patients with T2DM. Thus, in the current study, we set out to test the hypothesis that misexpression of SLC4A4/NBCe1 in T2DM β cells contributes to β cell dysfunction and impaired glucose homeostasis. To address this hypothesis, we first confirmed induction of SLC4A4/NBCe1 expression in β cells of patients with T2DM and demonstrated that its expression was associated with loss of β cell transcriptional identity, intracellular alkalinization, and β cell dysfunction. In addition, we generated a β cell-selective Slc4a4/NBCe1-KO mouse model and found that these mice were protected from diet-induced metabolic stress and β cell dysfunction. Importantly, improved glucose tolerance and enhanced β cell function in Slc4a4/NBCe1-deficient mice were due to augmented mitochondrial function and increased expression of genes regulating β cell identity and function. These results suggest that increased β cell expression of SLC4A4/NBCe1 in T2DM plays a contributory role in promotion of β cell failure and should be considered as a potential therapeutic target.
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Affiliation(s)
- Matthew R Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Heather Holmes
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Naureen Javeed
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Tracy K Her
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Alison A Stiller
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Satish Sen
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Y S Prakash
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA.,Department of Anesthesiology
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA.,Division of Nephrology and Hypertension and
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA.,Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, USA
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32
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Javeed N, Her TK, Brown MR, Vanderboom P, Rakshit K, Egan AM, Vella A, Lanza I, Matveyenko AV. Pro-inflammatory β cell small extracellular vesicles induce β cell failure through activation of the CXCL10/CXCR3 axis in diabetes. Cell Rep 2021; 36:109613. [PMID: 34433033 PMCID: PMC8420815 DOI: 10.1016/j.celrep.2021.109613] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/04/2021] [Accepted: 08/05/2021] [Indexed: 12/13/2022] Open
Abstract
Coordinated communication among pancreatic islet cells is necessary for maintenance of glucose homeostasis. In diabetes, chronic exposure to pro-inflammatory cytokines has been shown to perturb β cell communication and function. Compelling evidence has implicated extracellular vesicles (EVs) in modulating physiological and pathological responses to β cell stress. We report that pro-inflammatory β cell small EVs (cytokine-exposed EVs [cytoEVs]) induce β cell dysfunction, promote a pro-inflammatory islet transcriptome, and enhance recruitment of CD8+ T cells and macrophages. Proteomic analysis of cytoEVs shows enrichment of the chemokine CXCL10, with surface topological analysis depicting CXCL10 as membrane bound on cytoEVs to facilitate direct binding to CXCR3 receptors on the surface of β cells. CXCR3 receptor inhibition reduced CXCL10-cytoEV binding and attenuated β cell dysfunction, inflammatory gene expression, and leukocyte recruitment to islets. This work implies a significant role of pro-inflammatory β cell-derived small EVs in modulating β cell function, global gene expression, and antigen presentation through activation of the CXCL10/CXCR3 axis.
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Affiliation(s)
- Naureen Javeed
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
| | - Tracy K Her
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew R Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Patrick Vanderboom
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Ian Lanza
- Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA; Division of Endocrinology, Diabetes, and Metabolism, Mayo Clinic, Rochester, MN 55905, USA
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Abstract
BACKGROUND Obesity has been proven to be a risk factor for type 2 diabetes mellitus (T2DM) through numerous pathogenetic mechanisms. Unexpectedly, some studies suggest that subjects with overweight/obesity and T2DM have better clinical outcome than their normal weight peers. This finding is described as "obesity paradox" and calls into question the importance of weight loss in this specific population. OBJECTIVE This article is a narrative overview on the obesity and type 2 diabetes mellitus, particularly regarding the obesity paradox in T2DM patients. METHODS We used as sources MEDLINE/PubMed, CINAHL, EMBASE, and Cochrane Library, from inception to March 2020; we chose 30 relevant papers regarding the association of obesity with clinical outcome and mortality of patients affected by T2DM. RESULTS Many studies report that in patients with T2DM, overweight and obesity are associated with a better prognosis than underweight or normal weight, suggesting the presence of an obesity paradox. However, these studies have numerous limitations due to their mainly retrospective nature and to numerous confounding factors, such as associated pathologies, antidiabetic treatments, smoking habit, lack of data about distribution of body fat or weight history. CONCLUSION Literature data regarding the phenomenon of obesity paradox in T2DM patients are controversial due to the several limitations of the studies; therefore in the management of patients with overweight/obesity and T2DM is recommended referring to the established guidelines, which indicate diet and physical activity as the cornerstone of the treatment. LEVEL OF EVIDENCE Level V: narrative review.
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34
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Dysfunction of Persisting β Cells Is a Key Feature of Early Type 2 Diabetes Pathogenesis. Cell Rep 2021; 31:107469. [PMID: 32268101 DOI: 10.1016/j.celrep.2020.03.033] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 02/03/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
Type 2 diabetes is characterized by peripheral insulin resistance and insufficient insulin release from pancreatic islet β cells. However, the role and sequence of β cell dysfunction and mass loss for reduced insulin levels in type 2 diabetes pathogenesis are unclear. Here, we exploit freshly explanted pancreas specimens from metabolically phenotyped surgical patients using an in situ tissue slice technology. This approach allows assessment of β cell volume and function within pancreas samples of metabolically stratified individuals. We show that, in tissue of pre-diabetic, impaired glucose-tolerant subjects, β cell volume is unchanged, but function significantly deteriorates, exhibiting increased basal release and loss of first-phase insulin secretion. In individuals with type 2 diabetes, function within the sustained β cell volume further declines. These results indicate that dysfunction of persisting β cells is a key factor in the early development and progression of type 2 diabetes, representing a major target for diabetes prevention and therapy.
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35
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Hallakou‐Bozec S, Kergoat M, Moller DE, Bolze S. Imeglimin preserves islet β-cell mass in Type 2 diabetic ZDF rats. Endocrinol Diabetes Metab 2021; 4:e00193. [PMID: 33855202 PMCID: PMC8029531 DOI: 10.1002/edm2.193] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/29/2020] [Accepted: 10/04/2020] [Indexed: 12/13/2022] Open
Abstract
Objectives Type 2 diabetes (T2D) is driven by progressive dysfunction and loss of pancreatic β-cell mass. Imeglimin is a first-in-class novel drug candidate that improves glycaemia and glucose-stimulated insulin secretion in preclinical models and patients. Given evidence that imeglimin can attenuate β-cell dysfunction and protect β cells in vitro, we postulated that imeglimin could also exert longer term effects to prevent pancreatic β-cell death and preserve functional β-cell mass in vivo. Methods Zucker diabetic fatty (ZDF) male rats were treated by oral gavage with imeglimin at a standard dose of 150 mg/kg or vehicle, twice daily for five weeks. At treatment completion, oral glucose tolerance tests were performed in fasted animals before a thorough histomorphometry and immunohistochemical analysis was conducted on pancreas tissue slices to assess cellular composition and disease status. Results Imeglimin treatment significantly improved glucose-stimulated insulin secretion (augmentation of the insulinogenic index) and improved glycaemia. Both basal insulinaemia and pancreatic insulin content were also increased by imeglimin. In ZDF control rats, islet structure was disordered with few β-cells; after imeglimin treatment, islets appeared healthier with more normal morphology in association with a significant increase in insulin-positive β-cells. The increase in β-cell mass was associated with a greater degree of β-cell proliferation in the presence of reduced apoptosis. Unexpectedly, a decrease in as a α-cell mass was also documented due to an apparent antiproliferative effect of imeglimin on this cell type. Conclusion In male ZDF rats, chronic imeglimin treatment corrects a paramount component of type 2 diabetes progression: progressive loss of functional β-cell mass. In addition, imeglimin may also moderate a-cell turnover to further ameliorate hyperglycaemia. Cumulatively, these cellular effects suggest that imeglimin may provide for disease modifying effects to preserve functional β-cell mass.
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36
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Grau-Bové C, Ginés I, Beltrán-Debón R, Terra X, Blay MT, Pinent M, Ardévol A. Glucagon Shows Higher Sensitivity than Insulin to Grapeseed Proanthocyanidin Extract (GSPE) Treatment in Cafeteria-Fed Rats. Nutrients 2021; 13:nu13041084. [PMID: 33810265 PMCID: PMC8066734 DOI: 10.3390/nu13041084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/20/2021] [Accepted: 03/24/2021] [Indexed: 11/16/2022] Open
Abstract
The endocrine pancreas plays a key role in metabolism. Procyanidins (GSPE) targets β-cells and glucagon-like peptide-1 (GLP-1)-producing cells; however, there is no information on the effects of GSPE on glucagon. We performed GSPE preventive treatments administered to Wistar rats before or at the same time as they were fed a cafeteria diet during 12 or 17 weeks. We then measured the pancreatic function and GLP-1 production. We found that glucagonemia remains modified by GSPE pre-treatment several weeks after the treatment has finished. The animals showed a higher GLP-1 response to glucose stimulation, together with a trend towards a higher GLP-1 receptor expression in the pancreas. When the GSPE treatment was administered every second week, the endocrine pancreas behaved differently. We show here that glucagon is a more sensitive parameter than insulin to GSPE treatments, with a secretion that is highly linked to GLP-1 ileal functionality and dependent on the type of treatment.
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37
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Henquin JC. Glucose-induced insulin secretion in isolated human islets: Does it truly reflect β-cell function in vivo? Mol Metab 2021; 48:101212. [PMID: 33737253 PMCID: PMC8065218 DOI: 10.1016/j.molmet.2021.101212] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Diabetes always involves variable degrees of β-cell demise and malfunction leading to insufficient insulin secretion. Besides clinical investigations, many research projects used rodent islets to study various facets of β-cell pathophysiology. Their important contributions laid the foundations of steadily increasing numbers of experimental studies resorting to isolated human islets. SCOPE OF REVIEW This review, based on an analysis of data published over 60 years of clinical investigations and results of more recent studies in isolated islets, addresses a question of translational nature. Does the information obtained in vitro with human islets fit with our knowledge of insulin secretion in man? The aims are not to discuss specificities of pathways controlling secretion but to compare qualitative and quantitative features of glucose-induced insulin secretion in isolated human islets and in living human subjects. MAJOR CONCLUSIONS Much of the information gathered in vitro can reliably be translated to the in vivo situation. There is a fairly good, though not complete, qualitative and quantitative coherence between insulin secretion rates measured in vivo and in vitro during stimulation with physiological glucose concentrations, but the concordance fades out under extreme conditions. Perplexing discrepancies also exist between insulin secretion in subjects with Type 2 diabetes and their islets studied in vitro, in particular concerning the kinetics. Future projects should ascertain that the experimental conditions are close to physiological and do not alter the function of normal and diabetic islets.
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Affiliation(s)
- Jean-Claude Henquin
- Unit of Endocrinology and Metabolism, Faculty of Medicine, University of Louvain, Brussels, Belgium.
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38
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Zhou R, Lin C, Cheng Y, Zhuo X, Li Q, Xu W, Zhao L, Yang L. Liraglutide Alleviates Hepatic Steatosis and Liver Injury in T2MD Rats via a GLP-1R Dependent AMPK Pathway. Front Pharmacol 2021; 11:600175. [PMID: 33746742 PMCID: PMC7970416 DOI: 10.3389/fphar.2020.600175] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/18/2020] [Indexed: 12/11/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD), ranging from non-alcoholic fatty liver to non-alcoholic steatohepatitis, can be prevalent in patients with type 2 diabetes mellitus (T2DM). However, no antidiabetic drug has been approved for the treatment of NAFLD in T2DM patients. Multiple daily injections of basal-bolus insulin are often the final therapeutic option for T2DM. We found that insulin treatment aggravated hepatic steatosis and oxidative stress in Zucker diabetic fatty (ZDF) rats. In addition to glycaemic control, we demonstrated the stimulatory role of liraglutide in relieving hepatic steatosis and liver injury in ZDF rats. Interestingly, liraglutide could also alleviate insulin-aggravated hepatic fatty accumulation. The glucagon-like peptide-1 (GLP-1) agonists liraglutide and Ex-4 activated the expression of peroxisome proliferator-activated receptor alpha (PPARα) via a GLP-1 receptor-dependent 5′ AMP-activated protein kinase pathway. As a nuclear transcription factor, PPARα could mediate the effect of GLP-1 in alleviating hepatic steatosis by differentially regulating the expression of its target genes, including acetyl CoA carboxylase and carnitine palmitoyl transferase la both in vitro and in vivo. Moreover, GLP-1 could relieve liver injury by decreasing oxidative stress stimulated by hepatic steatosis. Insulin might aggravate hepatic steatosis and liver injury by inhibiting GLP-1R expression. The findings indicate the feasibility of liraglutide treatment combined with basal insulin in attenuating hepatic steatosis and liver injury in ZDF rats. This knowledge, and the evidence for the underlying mechanism, provide a theoretical basis for the combination treatment recommended by the latest clinical practice guidelines for T2DM.
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Affiliation(s)
- Rui Zhou
- Department of Nutrition, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Chuman Lin
- Department of Nutrition, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Yanzhen Cheng
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoyun Zhuo
- Department of Nutrition, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Qinghua Li
- Department of Nutrition, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Wen Xu
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Liang Zhao
- Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Li Yang
- Department of Nutrition, Zhujiang Hospital, Southern Medical University, Guangzhou, China.,Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
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Hallakou‐Bozec S, Vial G, Kergoat M, Fouqueray P, Bolze S, Borel A, Fontaine E, Moller DE. Mechanism of action of Imeglimin: A novel therapeutic agent for type 2 diabetes. Diabetes Obes Metab 2021; 23:664-673. [PMID: 33269554 PMCID: PMC8049051 DOI: 10.1111/dom.14277] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/15/2020] [Accepted: 11/28/2020] [Indexed: 02/06/2023]
Abstract
Imeglimin is an investigational first-in-class novel oral agent for the treatment of type 2 diabetes (T2D). Several pivotal phase III trials have been completed with evidence of statistically significant glucose lowering and a generally favourable safety and tolerability profile, including the lack of severe hypoglycaemia. Imeglimin's mechanism of action involves dual effects: (a) amplification of glucose-stimulated insulin secretion (GSIS) and preservation of β-cell mass; and (b) enhanced insulin action, including the potential for inhibition of hepatic glucose output and improvement in insulin signalling in both liver and skeletal muscle. At a cellular and molecular level, Imeglimin's underlying mechanism may involve correction of mitochondrial dysfunction, a common underlying element of T2D pathogenesis. It has been observed to rebalance respiratory chain activity (partial inhibition of Complex I and correction of deficient Complex III activity), resulting in reduced reactive oxygen species formation (decreasing oxidative stress) and prevention of mitochondrial permeability transition pore opening (implicated in preventing cell death). In islets derived from diseased rodents with T2D, Imeglimin also enhances glucose-stimulated ATP generation and induces the synthesis of nicotinamide adenine dinucleotide (NAD+ ) via the 'salvage pathway'. In addition to playing a key role as a mitochondrial co-factor, NAD+ metabolites may contribute to the increase in GSIS (via enhanced Ca++ mobilization). Imeglimin has also been shown to preserve β-cell mass in rodents with T2D. Overall, Imeglimin appears to target a key root cause of T2D: defective cellular energy metabolism. This potential mode of action is unique and has been shown to differ from that of other major therapeutic classes, including biguanides, sulphonylureas and glucagon-like peptide-1 receptor agonists.
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Affiliation(s)
| | - Guillaume Vial
- Université Grenoble AlpesGrenobleFrance
- Inserm U 1042, Laboratoire INSERM U1042, Hypoxia PathoPhysiology (HP2)GrenobleFrance
| | | | | | | | - Anne‐Laure Borel
- Université Grenoble AlpesGrenobleFrance
- Inserm U 1042, Laboratoire INSERM U1042, Hypoxia PathoPhysiology (HP2)GrenobleFrance
- Centre Hospitalier Universitaire Grenoble Alpes, département de Endocrinologie‐diabétologie‐Nutrition, Centre Spécialisé de l'Obésité Grenoble Arc AlpinGrenobleFrance
| | - Eric Fontaine
- Université Grenoble Alpes, LBFAGrenobleFrance
- Inserm U 1055, LBFAGrenobleFrance
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40
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Abdelalim EM. Modeling different types of diabetes using human pluripotent stem cells. Cell Mol Life Sci 2021; 78:2459-2483. [PMID: 33242105 PMCID: PMC11072720 DOI: 10.1007/s00018-020-03710-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/19/2020] [Accepted: 11/11/2020] [Indexed: 12/22/2022]
Abstract
Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia as a result of progressive loss of pancreatic β cells, which could lead to several debilitating complications. Different paths, triggered by several genetic and environmental factors, lead to the loss of pancreatic β cells and/or function. Understanding these many paths to β cell damage or dysfunction could help in identifying therapeutic approaches specific for each path. Most of our knowledge about diabetes pathophysiology has been obtained from studies on animal models, which do not fully recapitulate human diabetes phenotypes. Currently, human pluripotent stem cell (hPSC) technology is a powerful tool for generating in vitro human models, which could provide key information about the disease pathogenesis and provide cells for personalized therapies. The recent progress in generating functional hPSC-derived β cells in combination with the rapid development in genomic and genome-editing technologies offer multiple options to understand the cellular and molecular mechanisms underlying the development of different types of diabetes. Recently, several in vitro hPSC-based strategies have been used for studying monogenic and polygenic forms of diabetes. This review summarizes the current knowledge about different hPSC-based diabetes models and how these models improved our current understanding of the pathophysiology of distinct forms of diabetes. Also, it highlights the progress in generating functional β cells in vitro, and discusses the current challenges and future perspectives related to the use of the in vitro hPSC-based strategies.
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Affiliation(s)
- Essam M Abdelalim
- Diabetes Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), PO Box 34110, Doha, Qatar.
- College of Health and Life Sciences, Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Education City, Doha, Qatar.
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Hallakou-Bozec S, Kergoat M, Fouqueray P, Bolze S, Moller DE. Imeglimin amplifies glucose-stimulated insulin release from diabetic islets via a distinct mechanism of action. PLoS One 2021; 16:e0241651. [PMID: 33606677 PMCID: PMC7894908 DOI: 10.1371/journal.pone.0241651] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/02/2020] [Indexed: 01/09/2023] Open
Abstract
Pancreatic islet β-cell dysfunction is characterized by defective glucose-stimulated insulin secretion (GSIS) and is a predominant component of the pathophysiology of diabetes. Imeglimin, a novel first-in-class small molecule tetrahydrotriazine drug candidate, improves glycemia and GSIS in preclinical models and clinical trials in patients with Type 2 diabetes; however, the mechanism by which it restores β-cell function is unknown. Here, we show that imeglimin acutely and directly amplifies GSIS in islets isolated from rodents with Type 2 diabetes via a mode of action that is distinct from other known therapeutic approaches. The underlying mechanism involves increases in the cellular nicotinamide adenine dinucleotide (NAD+) pool-potentially via the salvage pathway and induction of nicotinamide phosphoribosyltransferase (NAMPT) along with augmentation of glucose-induced ATP levels. Further, additional results suggest that NAD+ conversion to a second messenger, cyclic ADP ribose (cADPR), via ADP ribosyl cyclase/cADPR hydrolase (CD38) is required for imeglimin's effects in islets, thus representing a potential link between increased NAD+ and enhanced glucose-induced Ca2+ mobilization which-in turn-is known to drive insulin granule exocytosis. Collectively, these findings implicate a novel mode of action for imeglimin that explains its ability to effectively restore-β-cell function and provides for a new approach to treat patients suffering from Type 2 diabetes.
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Bahl V, Lee May C, Perez A, Glaser B, Kaestner KH. Genetic activation of α-cell glucokinase in mice causes enhanced glucose-suppression of glucagon secretion during normal and diabetic states. Mol Metab 2021; 49:101193. [PMID: 33610858 PMCID: PMC7973249 DOI: 10.1016/j.molmet.2021.101193] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/03/2021] [Accepted: 02/11/2021] [Indexed: 12/31/2022] Open
Abstract
Objective While the molecular events controlling insulin secretion from β-cells have been documented in detail, the exact mechanisms governing glucagon release by α-cells are understood only partially. This is a critical knowledge gap, as the normal suppression of glucagon secretion by elevated glucose levels fails in type 2 diabetes (T2D) patients, contributing to hyperglycemia through stimulation of hepatic glucose production. A critical role of glycolytic flux in regulating glucagon secretion was supported by recent studies in which manipulation of the activity and expression of the glycolytic enzyme glucokinase altered the setpoint for glucose-suppression of glucagon secretion (GSGS). Given this precedent, we hypothesized that genetic activation of glucokinase specifically in α-cells would enhance GSGS and mitigate T2D hyperglucagonemia. Methods We derived an inducible, α-cell-specific glucokinase activating mutant mouse model (GckLoxPGck∗/LoxPGck∗; Gcg-CreERT2; henceforth referred to as “α-mutGCK”) in which the wild-type glucokinase gene (GCK) is conditionally replaced with a glucokinase mutant allele containing the ins454A activating mutation (Gck∗), a mutation that increases the affinity of glucokinase for glucose by almost 7-fold. The effects of α-cell GCK activation on glucose homeostasis, hormone secretion, islet morphology, and islet numbers were assessed using both in vivo and ex vivo assays. Additionally, the effect of α-cell GCK activation on GSGS was investigated under diabetogenic conditions of high-fat diet (HFD) feeding that dysregulate glucagon secretion. Results Our study shows that α-mutGCK mice have enhanced GSGS in vivo and ex vivo, independent of alterations in insulin levels and secretion, islet hormone content, islet morphology, or islet number. α-mutGCK mice maintained on HFD displayed improvements in glucagonemia compared to controls, which developed the expected obesity, glucose intolerance, elevated fasting blood glucose, hyperinsulinemia, and hyperglucagonemia. Conclusions Using our novel α-cell specific activation of GCK mouse model, we have provided additional support to demonstrate that the glycolytic enzyme glucokinase is a key determinant in glucose sensing within α-cells to regulate glucagon secretion. Our results contribute to our fundamental understanding of α-cell biology by providing greater insight into the regulation of glucagon secretion through α-cell intrinsic mechanisms via glucokinase. Furthermore, our HFD results underscore the potential of glucokinase as a druggable target which, given the ongoing development of allosteric glucokinase activators (GKAs) for T2D treatment, could help mitigate hyperglucagonemia and potentially improve blood glucose homeostasis. Inducible and cell type-specific point mutation in glucokinase enables analysis of glucose suppression of glucagon secretion. Glycolytic flux through glucokinase determines the set-point for glucagon secretion in pancreatic α-cells. Pancreatic α-cells are a physiologically relevant target of glucokinase activator drugs.
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Affiliation(s)
- Varun Bahl
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
| | - Catherine Lee May
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
| | - Alanis Perez
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
| | - Benjamin Glaser
- Endocrinology and Metabolism Department, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel.
| | - Klaus H Kaestner
- Institute of Diabetes, Obesity, and Metabolism, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, The University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
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Duque Escobar J, Kutschenko A, Schröder S, Blume R, Köster KA, Painer C, Lemcke T, Maison W, Oetjen E. Regulation of dual leucine zipper kinase activity through its interaction with calcineurin. Cell Signal 2021; 82:109953. [PMID: 33600948 DOI: 10.1016/j.cellsig.2021.109953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 11/19/2022]
Abstract
Hyperglycemia enhancing the intracellular levels of reactive oxygen species (ROS) contributes to dysfunction and progressive loss of beta cells and thereby to diabetes mellitus. The oxidation sensitive calcium/calmodulin dependent phosphatase calcineurin promotes pancreatic beta cell function and survival whereas the dual leucine zipper kinase (DLK) induces apoptosis. Therefore, it was studied whether calcineurin interferes with DLK action. In a beta cell line similar concentrations of H2O2 decreased calcineurin activity and activated DLK. DLK interacted via its φLxVP motif (aa 362-365) with the interface of the calcineurin subunits A and B. Mutation of the Val prevented this protein protein interaction, hinting at a distinct φLxVP motif. Indeed, mutational analysis revealed an ordered structure of DLK's φLxVP motif whereby Val mediates the interaction with calcineurin and Leu maintains an enzymatically active conformation. Overexpression of DLK wild-type but not the DLK mutant unable to bind calcineurin diminished calcineurin-induced nuclear localisation of the nuclear factor of activated T-cells (NFAT), suggesting that both, DLK and NFAT compete for the substrate binding site of calcineurin. The calcineurin binding-deficient DLK mutant exhibited increased DLK activity measured as phosphorylation of the downstream c-Jun N-terminal kinase, inhibition of CRE-dependent gene transcription and induction of apoptosis. These findings show that calcineurin interacts with DLK; and inhibition of calcineurin increases DLK activity. Hence, this study demonstrates a novel mechanism regulating DLK action. These findings suggest that ROS through inhibition of calcineurin enhance DLK activity and thereby lead to beta cell dysfunction and loss and ultimately diabetes mellitus.
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Affiliation(s)
- J Duque Escobar
- Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany; DZHK Standort Hamburg, Kiel, Lübeck, Germany
| | - Anna Kutschenko
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37099 Göttingen, Germany
| | - Sabine Schröder
- Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Roland Blume
- Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37099 Göttingen, Germany
| | - Kyra-Alexandra Köster
- Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany; DZHK Standort Hamburg, Kiel, Lübeck, Germany
| | - Christina Painer
- Institute of Pharmacy, University of Hamburg, Bundesstr. 45, 20146 Hamburg, Germany
| | - Thomas Lemcke
- Institute of Pharmacy, University of Hamburg, Bundesstr. 45, 20146 Hamburg, Germany
| | - Wolfgang Maison
- Institute of Pharmacy, University of Hamburg, Bundesstr. 45, 20146 Hamburg, Germany
| | - Elke Oetjen
- Department of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany; DZHK Standort Hamburg, Kiel, Lübeck, Germany; Department of Pharmacology, University of Göttingen, Robert-Koch-Str. 40, 37099 Göttingen, Germany; Institute of Pharmacy, University of Hamburg, Bundesstr. 45, 20146 Hamburg, Germany.
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Kang SM, Jung HS, Kwon MJ, Lee SH, Park JH. Testosterone Protects Pancreatic β-cells from Apoptosis and Stress-Induced Accelerated Senescence. World J Mens Health 2021; 39:724-732. [PMID: 33474846 PMCID: PMC8443983 DOI: 10.5534/wjmh.200169] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/06/2020] [Accepted: 10/19/2020] [Indexed: 12/22/2022] Open
Abstract
Purpose Androgens are steroid hormones that are very important in the sexual development and the maintenance of male reproductive system, and also have diverse actions in non-reproductive tissues, including potent antioxidant capacity. Type 2 diabetes mellitus is caused by tissue insulin resistance and insufficient insulin secretion from the pancreatic β-cells. The progressive decline of pancreatic β-cells in diabetes is closely related with the severity of disease. We wanted to know whether dihydrotestosterone (DHT) can protect insulin secreting pancreatic β-cells from apoptosis and accelerated senescence induced by oxidative stress. Materials and Methods Cultured INS-1 cells were used. Various concentrations of H2O2 were applied to exert oxidative stresses. The degrees of apoptosis, accelerated senescence, and the changes of the expressions of related signaling molecules after the application of DHT were analyzed by CCK-8, p16 expression, SA-β-Gal staining, reverse transcription polymerase chain reactions and Western blots. Results The application of H2O2 significantly increased (p<0.05) the degree of senescence and apoptosis of cultured INS-1 β-cells. DHT not only showed anti-oxidant protective capacity, but also significantly reduced (p<0.05) the degree of accelerated senescence. Conclusions DHT effectively protects pancreatic islet INS-1 β-cells from H2O2 induced oxidative stress.
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Affiliation(s)
- Seon Mee Kang
- Department of Internal Medicine, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan, Korea.,Paik Institute for Clinical Research, Inje University, Busan, Korea
| | - Hye Sook Jung
- Paik Institute for Clinical Research, Inje University, Busan, Korea
| | - Min Jeong Kwon
- Department of Internal Medicine, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan, Korea
| | - Soon Hee Lee
- Department of Internal Medicine, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan, Korea.
| | - Jeong Hyun Park
- Department of Internal Medicine, Inje University Busan Paik Hospital, College of Medicine, Inje University, Busan, Korea.,Paik Institute for Clinical Research, Inje University, Busan, Korea
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45
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MacFarlane EM, Bruin JE. Human Pluripotent Stem Cells: A Unique Tool for Toxicity Testing in Pancreatic Progenitor and Endocrine Cells. Front Endocrinol (Lausanne) 2021; 11:604998. [PMID: 33542706 PMCID: PMC7851047 DOI: 10.3389/fendo.2020.604998] [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: 09/11/2020] [Accepted: 11/27/2020] [Indexed: 12/18/2022] Open
Abstract
Diabetes prevalence is increasing worldwide, and epidemiological studies report an association between diabetes incidence and environmental pollutant exposure. There are >84,000 chemicals in commerce, many of which are released into the environment without a clear understanding of potential adverse health consequences. While in vivo rodent studies remain an important tool for testing chemical toxicity systemically, we urgently need high-throughput screening platforms in biologically relevant models to efficiently prioritize chemicals for in depth toxicity analysis. Given the increasing global burden of obesity and diabetes, identifying chemicals that disrupt metabolism should be a high priority. Pancreatic endocrine cells are key regulators of systemic metabolism, yet often overlooked as a target tissue in toxicology studies. Immortalized β-cell lines and primary human, porcine, and rodent islets are widely used for studying the endocrine pancreas in vitro, but each have important limitations in terms of scalability, lifespan, and/or biological relevance. Human pluripotent stem cell (hPSC) culture is a powerful tool for in vitro toxicity testing that addresses many of the limitations with other β-cell models. Current in vitro differentiation protocols can efficiently generate glucose-responsive insulin-secreting β-like cells that are not fully mature, but still valuable for high-throughput toxicity screening in vitro. Furthermore, hPSCs can be applied as a model of developing pancreatic endocrine cells to screen for chemicals that influence endocrine cell formation during critical windows of differentiation. Given their versatility, we recommend using hPSCs to identify potential β-cell toxins, which can then be prioritized as chemicals of concern for metabolic disruption.
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Affiliation(s)
| | - Jennifer E. Bruin
- Department of Biology & Institute of Biochemistry, Carleton University, Ottawa, ON, Canada
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Farrugia F, Aquilina A, Vassallo J, Pace NP. Bisphenol A and Type 2 Diabetes Mellitus: A Review of Epidemiologic, Functional, and Early Life Factors. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:E716. [PMID: 33467592 PMCID: PMC7830729 DOI: 10.3390/ijerph18020716] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/10/2021] [Accepted: 01/13/2021] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is characterised by insulin resistance and eventual pancreatic β-cell dysfunction, resulting in persistent high blood glucose levels. Endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA) are currently under scrutiny as they are implicated in the development of metabolic diseases, including T2DM. BPA is a pervasive EDC, being the main constituent of polycarbonate plastics. It can enter the human body by ingestion, through the skin, and cross from mother to offspring via the placenta or breast milk. BPA is a xenoestrogen that alters various aspects of beta cell metabolism via the modulation of oestrogen receptor signalling. In vivo and in vitro models reveal that varying concentrations of BPA disrupt glucose homeostasis and pancreatic β-cell function by altering gene expression and mitochondrial morphology. BPA also plays a role in the development of insulin resistance and has been linked to long-term adverse metabolic effects following foetal and perinatal exposure. Several epidemiological studies reveal a significant association between BPA and the development of insulin resistance and impaired glucose homeostasis, although conflicting findings driven by multiple confounding factors have been reported. In this review, the main findings of epidemiological and functional studies are summarised and compared, and their respective strengths and limitations are discussed. Further research is essential for understanding the exact mechanism of BPA action in various tissues and the extent of its effects on humans at environmentally relevant doses.
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Affiliation(s)
- Francesca Farrugia
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
| | - Alexia Aquilina
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
| | - Josanne Vassallo
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
- Centre for Molecular Medicine and Biobanking, University of Malta, MSD 2080 Msida, Malt
| | - Nikolai Paul Pace
- Department of Physiology and Biochemistry, University of Malta, MSD 2080 Msida, Malta; (F.F.); (A.A.); (J.V.)
- Centre for Molecular Medicine and Biobanking, University of Malta, MSD 2080 Msida, Malt
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Chan PC, Liao MT, Lu CH, Tian YF, Hsieh PS. Targeting inhibition of CCR5 on improving obesity-associated insulin resistance and impairment of pancreatic insulin secretion in high fat-fed rodent models. Eur J Pharmacol 2021; 891:173703. [PMID: 33159935 DOI: 10.1016/j.ejphar.2020.173703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 10/23/2022]
Abstract
Obesity is closely linked with type 2 diabetes and the effective therapies on obesity-associated diabetes are under development. The aim of this study was undertaken to investigate whether the inhibition of the augmented CCR5-mediated signaling could be a common target for treatment of obesity-associated insulin resistance and impairment of pancreatic insulin secretion in high-fat diet (HFD) fed rats and CCR5 knockout mice and also in isolated islets and RIN-m5F cells. Conducted with SD rats, HFD-induced body weight gain was significantly decreased in those combined with Maraviroc treatment, but food intake remained similar compared to control. Maraviroc also significantly improved the impaired oral glucose tolerance test (OGTT). As compared with wild-type mice, CCR5 deletion significantly attenuated the HFD-induced increases in glucose area under curve of OGTT and the value of HOMA-IR as well as plasma lipid profile. It also reversed the HFD-suppressed gene expressions of GLUT4 and IRS-1 in adipose tissue. On the other hand, the HFD-associated islet macrophage and T-cell infiltration were significantly decreased in CCR5 KO mice. H2O2 significantly suppressed glucose-stimulated insulin secretion (GSIS) is isolated islets, which were significantly reversed in those cotreated with CCR5 mAb. H2O2 failed to change GSIS in those of CCR5 KO mice. The palmitate-induced reactive oxygen species production was significantly decreased in those cotreated with CCR5 antagonist in RIN-m5F cells. Collectively, it is suggested that targeting inhibition of the CCR5 mediated inflammatory pathway could not only improve obesity-associated insulin resistance but also directly alleviate pancreatic β-cell dysfunction.
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Affiliation(s)
- Pei-Chi Chan
- Department of Physiology & Biophysics, National Defense Medical Center (NDMC), Taipei, Taiwan
| | - Min-Tser Liao
- Department of Pediatrics, Taoyuan Armed Forces General Hospital, Taoyuan, 325, Taiwan; Department of Pediatrics, Tri-Service General Hospital, Taipei, 114, Taiwan
| | - Chieh-Hua Lu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, NDMC, Taipei, Taiwan
| | - Yu-Feng Tian
- Division of General Surgery, Department of Surgery, Yung Kung Campus, Chi-Mei Medical Center, Chia Nan University of Pharmacy & Science, Tainan, Taiwan
| | - Po-Shiuan Hsieh
- Department of Physiology & Biophysics, National Defense Medical Center (NDMC), Taipei, Taiwan; Institute of Preventive Medicine, NDMC, Taiwan; Department of Medical Research, Tri-Service General Hospital, Taipei, Taiwan.
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Amo-Shiinoki K, Tanabe K, Hoshii Y, Matsui H, Harano R, Fukuda T, Takeuchi T, Bouchi R, Takagi T, Hatanaka M, Takeda K, Okuya S, Nishimura W, Kudo A, Tanaka S, Tanabe M, Akashi T, Yamada T, Ogawa Y, Ikeda E, Nagano H, Tanizawa Y. Islet cell dedifferentiation is a pathologic mechanism of long-standing progression of type 2 diabetes. JCI Insight 2021; 6:143791. [PMID: 33427207 PMCID: PMC7821596 DOI: 10.1172/jci.insight.143791] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/18/2020] [Indexed: 01/09/2023] Open
Abstract
Dedifferentiation has been implicated in β cell dysfunction and loss in rodent diabetes. However, the pathophysiological significance in humans remains unclear. To elucidate this, we analyzed surgically resected pancreatic tissues of 26 Japanese subjects with diabetes and 11 nondiabetic subjects, who had been overweight during adulthood but had no family history of diabetes. The diabetic subjects were subclassified into 3 disease stage categories, early, advanced, and intermediate. Despite no numerical changes in endocrine cells immunoreactive for chromogranin A (ChgA), diabetic islets showed profound β cell loss, with an increase in α cells without an increase in insulin and glucagon double-positive cells. The proportion of dedifferentiated cells that retain ChgA immunoreactivity without 4 major islet hormones was strikingly increased in diabetic islets and rose substantially during disease progression. The increased dedifferentiated cell ratio was inversely correlated with declining C-peptide index. Moreover, a subset of islet cells converted into exocrine-like cells during disease progression. These results indicate that islet remodeling with dedifferentiation is the underlying cause of β cell failure during the course of diabetes progression in humans.
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Affiliation(s)
- Kikuko Amo-Shiinoki
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.,Department of Diabetes Research, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan
| | - Katsuya Tanabe
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Yoshinobu Hoshii
- Department of Diagnostic Pathology, Yamaguchi University Hospital, Ube, Yamaguchi, Japan
| | - Hiroto Matsui
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Risa Harano
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Tatsuya Fukuda
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takato Takeuchi
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ryotaro Bouchi
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Diabetes, Endocrinology and Metabolism, National Center for Global Health and Medicine, Tokyo, Japan
| | - Tokiyo Takagi
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Masayuki Hatanaka
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Komei Takeda
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Shigeru Okuya
- Health Administration Center, Yamaguchi University Organization for University Education, Yamaguchi, Japan
| | - Wataru Nishimura
- Department of Molecular Biology, International University of Health and Welfare School of Medicine, Chiba, Japan
| | - Atsushi Kudo
- Department of Hepatobiliary and Pancreatic Surgery
| | | | | | | | - Tetsuya Yamada
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshihiro Ogawa
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Molecular and Cellular Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,AMED-CREST, Tokyo, Japan
| | - Eiji Ikeda
- Department of Pathology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Hiroaki Nagano
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Yukio Tanizawa
- Division of Endocrinology, Metabolism, Hematological Sciences and Therapeutics, Department of Medicine, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
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Rakshit K, Matveyenko AV. Induction of Core Circadian Clock Transcription Factor Bmal1 Enhances β-Cell Function and Protects Against Obesity-Induced Glucose Intolerance. Diabetes 2021; 70:143-154. [PMID: 33087455 PMCID: PMC7881843 DOI: 10.2337/db20-0192] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/15/2020] [Indexed: 12/18/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by β-cell dysfunction as a result of impaired glucose-stimulated insulin secretion (GSIS). Studies show that β-cell circadian clocks are important regulators of GSIS and glucose homeostasis. These observations raise the question about whether enhancement of the circadian clock in β-cells will confer protection against β-cell dysfunction under diabetogenic conditions. To test this, we used an approach by first generating mice with β-cell-specific inducible overexpression of Bmal1 (core circadian transcription factor; β-Bmal1 OV ). We subsequently examined the effects of β-Bmal1 OV on the circadian clock, GSIS, islet transcriptome, and glucose metabolism in the context of diet-induced obesity. We also tested the effects of circadian clock-enhancing small-molecule nobiletin on GSIS in mouse and human control and T2DM islets. We report that β-Bmal1 OV mice display enhanced islet circadian clock amplitude and augmented in vivo and in vitro GSIS and are protected against obesity-induced glucose intolerance. These effects were associated with increased expression of purported BMAL1-target genes mediating insulin secretion, processing, and lipid metabolism. Furthermore, exposure of isolated islets to nobiletin enhanced β-cell secretory function in a Bmal1-dependent manner. This work suggests therapeutic targeting of the circadian system as a potential strategy to counteract β-cell failure under diabetogenic conditions.
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Affiliation(s)
- Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, MN
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic School of Medicine, Rochester, MN
- Division of Endocrinology, Metabolism, Diabetes, and Nutrition, Department of Medicine, Mayo Clinic School of Medicine, Rochester, MN
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Akter R, Zou J, Raleigh DP. Differential effects of serine side chain interactions in amyloid formation by islet amyloid polypeptide. Protein Sci 2020; 29:555-563. [PMID: 31705766 DOI: 10.1002/pro.3782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/05/2019] [Accepted: 11/05/2019] [Indexed: 01/20/2023]
Abstract
Islet amyloid polypeptide (IAPP), a 37 residue polypeptide, is the main protein component of islet amyloid deposits produced in the pancreas in Type 2 diabetes. Human IAPP contains five serine residues at positions 19, 20, 28, 29, and 34. Models of the IAPP amyloid fibril indicate a structure composed of two closely aligned columns of IAPP monomers with each monomer contributing to two intermolecular β-strands. Ser 19 and Ser 20 are in the partially ordered β-turn region, which links the two strands, whereas Ser 28, Ser 29, and Ser 34 are in the core region of the amyloid fibril. Ser 29 is involved in contacts between the two columns of monomers and is the part of the steric zipper interface. We undertook a study of individual serine substitutions with the hydrophobic isostere 2-aminobutyric acid (2-Abu) to examine the site-specific role of serine side chains in IAPP amyloid formation. All five variants formed amyloid. The Ser 19 to 2-Abu mutant accelerates amyloid formation by a factor of 3 to 4, while the Ser 29 to 2-Abu mutation modestly slows the rate of amyloid formation. 2-Abu replacements at the other sites had even smaller effects. The data demonstrate that the cross-column interactions made by residue 29 are not essential for amyloid formation and also show that cross-strand networks of hydrogen-bonded Ser side chains, so called Ser-ladders, are not required for IAPP amyloid formation. The effect of the Ser 19 to 2-Abu mutant suggests that residues in this region are important for amyloid formation by IAPP.
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Affiliation(s)
- Rehana Akter
- Department of Chemistry, Stony Brook University, Stony Brook, New York
| | - Junjie Zou
- Department of Chemistry, Stony Brook University, Stony Brook, New York.,Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York.,Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York
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