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Fitzgerald DM, Cash CM, Dudley KJ, Sibthorpe PEM, Sillence MN, de Laat MA. Expression of the GCG gene and secretion of active glucagon-like peptide-1 varies along the length of intestinal tract in horses. Equine Vet J 2024; 56:352-360. [PMID: 37853957 DOI: 10.1111/evj.14020] [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: 06/08/2023] [Accepted: 09/24/2023] [Indexed: 10/20/2023]
Abstract
BACKGROUND Active glucagon-like peptide-1 (aGLP-1) has been implicated in the pathogenesis of equine insulin dysregulation (ID), but its role is unclear. Cleavage of proglucagon (coded by the GCG gene) produces aGLP-1 in enteral L cells. OBJECTIVES The aim in vivo was to examine the sequence of the exons of GCG in horses with and without ID, where aGLP-1 was higher in the group with ID. The aims in vitro were to identify and quantify the expression of GCG in the equine intestine (as a marker of L cells) and determine intestinal secretion of aGLP-1. STUDY DESIGN Genomic studies were case-control studies. Expression and secretion studies in vitro were cross-sectional. METHODS The GCG gene sequence of the exons was determined using a hybridisation capture protocol. Expression and quantification of GCG in samples of stomach duodenum, jejunum, ileum, caecum and ascending and descending colon was achieved with droplet digital PCR. For secretory studies tissue explants were incubated with 12 mM glucose and aGLP-1 secretion was measured with an ELISA. RESULTS Although the median [IQR] post-prandial aGLP-1 concentrations were higher (p = 0.03) in animals with ID (10.2 [8.79-15.5]), compared with healthy animals (8.47 [6.12-11.7]), there was 100% pairwise identity of the exons of the GCG sequence for the cohort. The mRNA concentrations of GCG and secretion of aGLP-1 differed (p < 0.001) throughout the intestine. MAIN LIMITATIONS Only the exons of the GCG gene were sequenced and breeds were not compared. The horses used for the study in vitro were not assessed for ID and different horses were used for the small, and large, intestinal studies. CONCLUSIONS Differences in post-prandial aGLP-1 concentration were not due to a variant in the exons of the GCG gene sequence in this cohort. Both the large and small intestine are sites of GLP-1 secretion.
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Affiliation(s)
- Danielle M Fitzgerald
- Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Christina M Cash
- Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kevin J Dudley
- Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Poppy E M Sibthorpe
- Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Martin N Sillence
- Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Melody A de Laat
- Faculty of Science, Queensland University of Technology, Brisbane, Queensland, Australia
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2
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Jiang Y, Sun J, Chandrapala J, Majzoobi M, Brennan C, Zeng XA, Sun B. Current situation, trend, and prospects of research on functional components from by-products of baijiu production: A review. Food Res Int 2024; 180:114032. [PMID: 38395586 DOI: 10.1016/j.foodres.2024.114032] [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: 11/28/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 02/25/2024]
Abstract
In the present scenario marked by energy source shortages and escalating concerns regarding carbon dioxide emissions, there is a growing emphasis on the optimal utilization of biomass resources. Baijiu, as the Chinese national spirit, boasts remarkably high sales volumes annually. However, the production of baijiu yields various by-products, including solid residues (Jiuzao), liquid wastewater (Huangshui and waste alcohol), and gaseous waste. Recent years have witnessed dedicated research aimed at exploring the composition and potential applications of these by-products, seeking sustainable development and comprehensive resource utilization. This review systematically summarizes recent research, shedding light on both the baijiu brewing process and the bioactive compounds present baijiu production by-products (BPBPs). The primary focus lies in elucidating the potential extraction methods and applications of BPBPs, offering a practical approach to comprehensive utilization of by-products in functional food, medicine, cosmetic, and packaging fields. These applications not only contribute to enhancing production efficiency and mitigating environmental pollution, but also introduce innovative concepts for the sustainable advancement of associated industries. Future research avenues may include more in-depth compositional analysis, the development of utilization technologies, and the promotion of potential industrialization.
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Affiliation(s)
- Yunsong Jiang
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education, Beijing, People's Republic of China; School of Food Science and Engineering, South China University of Technology, Guangzhou, People's Republic of China; Biosciences and Food Technology, RMIT University, Bundoora West Campus, Plenty Road, Melbourne, VIC 3083 Australia
| | - Jinyuan Sun
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education, Beijing, People's Republic of China.
| | - Jayani Chandrapala
- Biosciences and Food Technology, RMIT University, Bundoora West Campus, Plenty Road, Melbourne, VIC 3083 Australia
| | - Mahsa Majzoobi
- Biosciences and Food Technology, RMIT University, Bundoora West Campus, Plenty Road, Melbourne, VIC 3083 Australia
| | - Charles Brennan
- Biosciences and Food Technology, RMIT University, Bundoora West Campus, Plenty Road, Melbourne, VIC 3083 Australia
| | - Xin-An Zeng
- School of Food Science and Engineering, South China University of Technology, Guangzhou, People's Republic of China.
| | - Baoguo Sun
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education, Beijing, People's Republic of China.
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3
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Bernardini F, Nusca A, Coletti F, La Porta Y, Piscione M, Vespasiano F, Mangiacapra F, Ricottini E, Melfi R, Cavallari I, Ussia GP, Grigioni F. Incretins-Based Therapies and Their Cardiovascular Effects: New Game-Changers for the Management of Patients with Diabetes and Cardiovascular Disease. Pharmaceutics 2023; 15:1858. [PMID: 37514043 PMCID: PMC10386670 DOI: 10.3390/pharmaceutics15071858] [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: 05/31/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Atherosclerosis is the leading cause of death worldwide, especially in patients with type 2 diabetes mellitus (T2D). GLP-1 receptor agonists and DPP-4 inhibitors were demonstrated to play a markedly protective role for the cardiovascular system beyond their glycemic control. Several cardiovascular outcome trials (CVOT) reported the association between using these agents and a significant reduction in cardiovascular events in patients with T2D and a high cardiovascular risk profile. Moreover, recent evidence highlights a favorable benefit/risk profile in myocardial infarction and percutaneous coronary revascularization settings. These clinical effects result from their actions on multiple molecular mechanisms involving the immune system, platelets, and endothelial and vascular smooth muscle cells. This comprehensive review specifically concentrates on these cellular and molecular processes mediating the cardiovascular effects of incretins-like molecules, aiming to improve clinicians' knowledge and stimulate a more extensive use of these drugs in clinical practice as helpful cardiovascular preventive strategies.
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Affiliation(s)
- Federico Bernardini
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Annunziata Nusca
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Federica Coletti
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Ylenia La Porta
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Mariagrazia Piscione
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Francesca Vespasiano
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Fabio Mangiacapra
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Elisabetta Ricottini
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Rosetta Melfi
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Ilaria Cavallari
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Gian Paolo Ussia
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
| | - Francesco Grigioni
- Unit of Cardiac Sciences, Department of Medicine, Campus Bio-Medico University of Rome, 00128 Rome, Italy
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4
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Goode RA, Hum JM, Kalwat MA. Therapeutic Strategies Targeting Pancreatic Islet β-Cell Proliferation, Regeneration, and Replacement. Endocrinology 2022; 164:6836713. [PMID: 36412119 PMCID: PMC9923807 DOI: 10.1210/endocr/bqac193] [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: 09/09/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022]
Abstract
Diabetes results from insufficient insulin production by pancreatic islet β-cells or a loss of β-cells themselves. Restoration of regulated insulin production is a predominant goal of translational diabetes research. Here, we provide a brief overview of recent advances in the fields of β-cell proliferation, regeneration, and replacement. The discovery of therapeutic targets and associated small molecules has been enabled by improved understanding of β-cell development and cell cycle regulation, as well as advanced high-throughput screening methodologies. Important findings in β-cell transdifferentiation, neogenesis, and stem cell differentiation have nucleated multiple promising therapeutic strategies. In particular, clinical trials are underway using in vitro-generated β-like cells from human pluripotent stem cells. Significant challenges remain for each of these strategies, but continued support for efforts in these research areas will be critical for the generation of distinct diabetes therapies.
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Affiliation(s)
- Roy A Goode
- Division of Biomedical Sciences, College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA
| | - Julia M Hum
- Division of Biomedical Sciences, College of Osteopathic Medicine, Marian University, Indianapolis, IN, USA
| | - Michael A Kalwat
- Correspondence: Michael A. Kalwat, PhD, Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, 1210 Waterway Blvd, Suite 2000, Indianapolis, IN 46202, USA. or
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5
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Jain C, Bilekova S, Lickert H. Targeting pancreatic β cells for diabetes treatment. Nat Metab 2022; 4:1097-1108. [PMID: 36131204 DOI: 10.1038/s42255-022-00618-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 07/13/2022] [Indexed: 11/09/2022]
Abstract
Insulin is a life-saving drug for patients with type 1 diabetes; however, even today, no pharmacotherapy can prevent the loss or dysfunction of pancreatic insulin-producing β cells to stop or reverse disease progression. Thus, pancreatic β cells have been a main focus for cell-replacement and regenerative therapies as a curative treatment for diabetes. In this Review, we highlight recent advances toward the development of diabetes therapies that target β cells to enhance proliferation, redifferentiation and protection from cell death and/or enable selective killing of senescent β cells. We describe currently available therapies and their mode of action, as well as insufficiencies of glucagon-like peptide 1 (GLP-1) and insulin therapies. We discuss and summarize data collected over the last decades that support the notion that pharmacological targeting of β cell insulin signalling might protect and/or regenerate β cells as an improved treatment of patients with diabetes.
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Affiliation(s)
- Chirag Jain
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Immunology Discovery, Genentech Inc., South San Francisco, CA, USA
| | - Sara Bilekova
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
- Chair of β-Cell Biology, Technische Universität München, School of Medicine, Klinikum Rechts der Isar, München, Germany.
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6
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Bourouh C, Courty E, Rolland L, Pasquetti G, Gromada X, Rabhi N, Carney C, Moreno M, Boutry R, Caron E, Benfodda Z, Meffre P, Kerr-Conte J, Pattou F, Froguel P, Bonnefond A, Oger F, Annicotte JS. The transcription factor E2F1 controls the GLP-1 receptor pathway in pancreatic β cells. Cell Rep 2022; 40:111170. [PMID: 35947949 DOI: 10.1016/j.celrep.2022.111170] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 04/11/2022] [Accepted: 07/15/2022] [Indexed: 11/03/2022] Open
Abstract
The glucagon-like peptide 1 (Glp-1) has emerged as a hormone with broad pharmacological potential in type 2 diabetes (T2D) treatment, notably by improving β cell functions. The cell-cycle regulator and transcription factor E2f1 is involved in glucose homeostasis by modulating β cell mass and function. Here, we report that β cell-specific genetic ablation of E2f1 (E2f1β-/-) impairs glucose homeostasis associated with decreased expression of the Glp-1 receptor (Glp1r) in E2f1β-/- pancreatic islets. Pharmacological inhibition of E2F1 transcriptional activity in nondiabetic human islets decreases GLP1R levels and blunts the incretin effect of GLP1R agonist exendin-4 (ex-4) on insulin secretion. Overexpressing E2f1 in pancreatic β cells increases Glp1r expression associated with enhanced insulin secretion mediated by ex-4. Interestingly, ex-4 induces retinoblastoma protein (pRb) phosphorylation and E2f1 transcriptional activity. Our findings reveal critical roles for E2f1 in β cell function and suggest molecular crosstalk between the E2F1/pRb and GLP1R signaling pathways.
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Affiliation(s)
- Cyril Bourouh
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France
| | - Emilie Courty
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France; Université de Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, 59000 Lille, France
| | - Laure Rolland
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France; Université de Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, 59000 Lille, France
| | - Gianni Pasquetti
- Université de Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1190 - EGID, 59000 Lille, France
| | - Xavier Gromada
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France
| | - Nabil Rabhi
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Charlène Carney
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France
| | - Maeva Moreno
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France
| | - Raphaël Boutry
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France
| | - Emilie Caron
- Université de Lille, INSERM, CHU Lille, U1172-LilNCog - Lille Neuroscience & Cognition - EGID - DISTALZ, 59000 Lille, France
| | - Zohra Benfodda
- Université de Nîmes, UPR CHROME, 30021 Nîmes Cedex 1, France
| | - Patrick Meffre
- Université de Nîmes, UPR CHROME, 30021 Nîmes Cedex 1, France
| | - Julie Kerr-Conte
- Université de Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1190 - EGID, 59000 Lille, France
| | - François Pattou
- Université de Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1190 - EGID, 59000 Lille, France
| | - Philippe Froguel
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France; Department of Metabolism, Imperial College London, Hammersmith Hospital, London W12 0NN, UK
| | - Amélie Bonnefond
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France; Department of Metabolism, Imperial College London, Hammersmith Hospital, London W12 0NN, UK
| | - Frédérik Oger
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France
| | - Jean-Sébastien Annicotte
- Université de Lille, INSERM, CNRS, CHU Lille, Institut Pasteur de Lille, U1283 - UMR 8199 - EGID, 59000 Lille, France; Université de Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Facteurs de Risque et Déterminants Moléculaires des Maladies Liées au Vieillissement, 59000 Lille, France.
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7
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Sun H, Qi X. The role of insulin and incretin-based drugs in biliary tract cancer: epidemiological and experimental evidence. Discov Oncol 2022; 13:70. [PMID: 35933633 PMCID: PMC9357599 DOI: 10.1007/s12672-022-00536-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 07/26/2022] [Indexed: 11/29/2022] Open
Abstract
Insulin and incretin-based drugs are important antidiabetic agents with complex effects on cell growth and metabolism. Emerging evidence shows that insulin and incretin-based drugs are associated with altered risk of biliary tract cancer (BTC). Observational study reveals that insulin is associated with an increased risk of extrahepatic cholangiocarcinoma (ECC), but not intrahepatic cholangiocarcinoma (ICC) or gallbladder cancer (GBC). This type-specific effect can be partly explained by the cell of origin and heterogeneous genome landscape of the three subtypes of BTC. Similar to insulin, incretin-based drugs also exhibit very interesting contradictions and inconsistencies in response to different cancer phenotypes, including BTC. Both epidemiological and experimental evidence suggests that incretin-based drugs can be a promoter of some cancers and an inhibitor of others. It is now more apparent that this type of drugs has a broader range of physiological effects on the body, including regulation of endoplasmic reticulum stress, autophagy, metabolic reprogramming, and gene expression. In particular, dipeptidyl peptidase-4 inhibitors (DPP-4i) have a more complex effect on cancer due to the multi-functional nature of DPP-4. DPP-4 exerts both catalytic and non-enzymatic functions to regulate metabolic homeostasis, immune reaction, cell migration, and proliferation. In this review, we collate the epidemiological and experimental evidence regarding the effect of these two classes of drugs on BTC to provide valuable information.
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Affiliation(s)
- Hua Sun
- Department of Geriatrics, Zhejiang Hospital of Integrated Traditional Chinese and Western Medicine, No.208 East Huancheng Road, Hangzhou, Zhejiang, China
| | - Xiaohui Qi
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No.197 Ruijin Er Road, Shanghai, China.
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, State Key Laboratory of Medical Genomics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No.573 Xujiahui Road, Shanghai, China.
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8
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Newsholme P, Rowlands J, Rose’Meyer R, Cruzat V. Metabolic Adaptions/Reprogramming in Islet Beta-Cells in Response to Physiological Stimulators—What Are the Consequences. Antioxidants (Basel) 2022; 11:antiox11010108. [PMID: 35052612 PMCID: PMC8773416 DOI: 10.3390/antiox11010108] [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: 11/12/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/25/2022] Open
Abstract
Irreversible pancreatic β-cell damage may be a result of chronic exposure to supraphysiological glucose or lipid concentrations or chronic exposure to therapeutic anti-diabetic drugs. The β-cells are able to respond to blood glucose in a narrow concentration range and release insulin in response, following activation of metabolic pathways such as glycolysis and the TCA cycle. The β-cell cannot protect itself from glucose toxicity by blocking glucose uptake, but indeed relies on alternative metabolic protection mechanisms to avoid dysfunction and death. Alteration of normal metabolic pathway function occurs as a counter regulatory response to high nutrient, inflammatory factor, hormone or therapeutic drug concentrations. Metabolic reprogramming is a term widely used to describe a change in regulation of various metabolic enzymes and transporters, usually associated with cell growth and proliferation and may involve reshaping epigenetic responses, in particular the acetylation and methylation of histone proteins and DNA. Other metabolic modifications such as Malonylation, Succinylation, Hydroxybutyrylation, ADP-ribosylation, and Lactylation, may impact regulatory processes, many of which need to be investigated in detail to contribute to current advances in metabolism. By describing multiple mechanisms of metabolic adaption that are available to the β-cell across its lifespan, we hope to identify sites for metabolic reprogramming mechanisms, most of which are incompletely described or understood. Many of these mechanisms are related to prominent antioxidant responses. Here, we have attempted to describe the key β-cell metabolic adaptions and changes which are required for survival and function in various physiological, pathological and pharmacological conditions.
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Affiliation(s)
- Philip Newsholme
- Curtin Medical School and CHIRI, Curtin University, Perth, WA 6845, Australia
- Correspondence: (P.N.); (J.R.)
| | - Jordan Rowlands
- Curtin Medical School and CHIRI, Curtin University, Perth, WA 6845, Australia
- Correspondence: (P.N.); (J.R.)
| | - Roselyn Rose’Meyer
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia;
| | - Vinicius Cruzat
- Faculty of Health, Torrens University Australia, Brisbane, QLD 4006, Australia;
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9
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Jiang Y, Zhu L, Wu D, Ni Y, Huang C, Ye H, Yang Y, Liu R, Li Y. Type IIB PKA is highly expressed in β cells and controls cell proliferation via regulating Cyclin D1 expression. FEBS J 2021; 289:2865-2876. [PMID: 34839588 DOI: 10.1111/febs.16302] [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: 09/21/2021] [Revised: 11/09/2021] [Accepted: 11/26/2021] [Indexed: 12/01/2022]
Abstract
β cell number is maintained mainly by cell proliferation and cell apoptosis. Protein kinase A (PKA) pathway is an important intracellular signalling-mediating β cell proliferation. However, the precise roles of PKA isoforms are not well-defined. We found that the RIIB subunit of PKA is expressed specifically by β cells of mouse and human islets. Sixty percent pancreatectomy caused increased β cell proliferation. Deletion of type IIB PKA by disruption of RIIB expression further promoted β cell proliferation, leading to enhanced β cell mass expansion. RIIB KO mice also showed increased insulin levels and improved glucose tolerance. Mechanistically, activation of type IIB PKA decreased Cyclin D1 levels and inhibition of RIIB expression increased Cyclin D1 levels. Consistently, activation of type IIB PKA inhibited cell cycle entry. These results suggest that type IIB PKA plays a pivotal role in β cell proliferation via regulating Cyclin D1 expression.
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Affiliation(s)
- Yaojing Jiang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Lu Zhu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Di Wu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Yunzhi Ni
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Chuxin Huang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Hongying Ye
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Yehong Yang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Rui Liu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Yiming Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
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10
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Serra-Navarro B, Fernandez-Ruiz R, García-Alamán A, Pradas-Juni M, Fernandez-Rebollo E, Esteban Y, Mir-Coll J, Mathieu J, Dalle S, Hahn M, Ahlgren U, Weinstein LS, Vidal J, Gomis R, Gasa R. Gsα-dependent signaling is required for postnatal establishment of a functional β-cell mass. Mol Metab 2021; 53:101264. [PMID: 34091063 PMCID: PMC8239471 DOI: 10.1016/j.molmet.2021.101264] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/17/2021] [Accepted: 05/30/2021] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVE Early postnatal life is a critical period for the establishment of the functional β-cell mass that will sustain whole-body glucose homeostasis during the lifetime. β cells are formed from progenitors during embryonic development but undergo significant expansion in quantity and attain functional maturity after birth. The signals and pathways involved in these processes are not fully elucidated. Cyclic adenosine monophosphate (cAMP) is an intracellular signaling molecule that is known to regulate insulin secretion, gene expression, proliferation, and survival of adult β cells. The heterotrimeric G protein Gs stimulates the cAMP-dependent pathway by activating adenylyl cyclase. In this study, we sought to explore the role of Gs-dependent signaling in postnatal β-cell development. METHODS To study Gs-dependent signaling, we generated conditional knockout mice in which the α subunit of the Gs protein (Gsα) was ablated from β-cells using the Cre deleter line Ins1Cre. Mice were characterized in terms of glucose homeostasis, including in vivo glucose tolerance, glucose-induced insulin secretion, and insulin sensitivity. β-cell mass was studied using histomorphometric analysis and optical projection tomography. β-cell proliferation was studied by ki67 and phospho-histone H3 immunostatining, and apoptosis was assessed by TUNEL assay. Gene expression was determined in isolated islets and sorted β cells by qPCR. Intracellular cAMP was studied in isolated islets using HTRF-based technology. The activation status of the cAMP and insulin-signaling pathways was determined by immunoblot analysis of the relevant components of these pathways in isolated islets. In vitro proliferation of dissociated islet cells was assessed by BrdU incorporation. RESULTS Elimination of Gsα in β cells led to reduced β-cell mass, deficient insulin secretion, and severe glucose intolerance. These defects were evident by weaning and were associated with decreased proliferation and inadequate expression of key β-cell identity and maturation genes in postnatal β-cells. Additionally, loss of Gsα caused a broad multilevel disruption of the insulin transduction pathway that resulted in the specific abrogation of the islet proliferative response to insulin. CONCLUSION We conclude that Gsα is required for β-cell growth and maturation in the early postnatal stage and propose that this is partly mediated via its crosstalk with insulin signaling. Our findings disclose a tight connection between these two pathways in postnatal β cells, which may have implications for using cAMP-raising agents to promote β-cell regeneration and maturation in diabetes.
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Affiliation(s)
- Berta Serra-Navarro
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; University of Barcelona, Barcelona, Spain
| | - Rebeca Fernandez-Ruiz
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Ainhoa García-Alamán
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Marta Pradas-Juni
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; University of Barcelona, Barcelona, Spain
| | - Eduardo Fernandez-Rebollo
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Yaiza Esteban
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Joan Mir-Coll
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; University of Barcelona, Barcelona, Spain
| | - Julia Mathieu
- CHU Montpellier, Laboratory of Cell Therapy for Diabetes (LTCD), Hospital St-Eloi, Montpellier, France
| | - Stephane Dalle
- CHU Montpellier, Laboratory of Cell Therapy for Diabetes (LTCD), Hospital St-Eloi, Montpellier, France
| | - Max Hahn
- Umeå Centre for Molecular Medicine (UCMM), Umeå, Sweden
| | - Ulf Ahlgren
- Umeå Centre for Molecular Medicine (UCMM), Umeå, Sweden
| | - Lee S Weinstein
- Metabolic Diseases Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Josep Vidal
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain; Department of Endocrinology and Nutrition, Hospital Clinic of Barcelona, Barcelona, Spain
| | - Ramon Gomis
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; University of Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain; Universitat Oberta de Catalunya (UOC), Barcelona, Spain
| | - Rosa Gasa
- Diabetes and Obesity Research Laboratory, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Rosselló 149-153, 08036, Barcelona, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain.
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11
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Sánchez-Archidona AR, Cruciani-Guglielmacci C, Roujeau C, Wigger L, Lallement J, Denom J, Barovic M, Kassis N, Mehl F, Weitz J, Distler M, Klose C, Simons K, Ibberson M, Solimena M, Magnan C, Thorens B. Plasma triacylglycerols are biomarkers of β-cell function in mice and humans. Mol Metab 2021; 54:101355. [PMID: 34634522 PMCID: PMC8602044 DOI: 10.1016/j.molmet.2021.101355] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/27/2021] [Accepted: 10/06/2021] [Indexed: 12/13/2022] Open
Abstract
Objectives To find plasma biomarkers prognostic of type 2 diabetes, which could also inform on pancreatic β-cell deregulations or defects in the function of insulin target tissues. Methods We conducted a systems biology approach to characterize the plasma lipidomes of C57Bl/6J, DBA/2J, and BALB/cJ mice under different nutritional conditions, as well as their pancreatic islet and liver transcriptomes. We searched for correlations between plasma lipids and tissue gene expression modules. Results We identified strong correlation between plasma triacylglycerols (TAGs) and islet gene modules that comprise key regulators of glucose- and lipid-regulated insulin secretion and of the insulin signaling pathway, the two top hits were Gck and Abhd6 for negative and positive correlations, respectively. Correlations were also found between sphingomyelins and islet gene modules that overlapped in part with the gene modules correlated with TAGs. In the liver, the gene module most strongly correlated with plasma TAGs was enriched in mRNAs encoding fatty acid and carnitine transporters as well as multiple enzymes of the β-oxidation pathway. In humans, plasma TAGs also correlated with the expression of several of the same key regulators of insulin secretion and the insulin signaling pathway identified in mice. This cross-species comparative analysis further led to the identification of PITPNC1 as a candidate regulator of glucose-stimulated insulin secretion. Conclusion TAGs emerge as biomarkers of a liver-to-β-cell axis that links hepatic β-oxidation to β-cell functional mass and insulin secretion. Plasma triacylglycerols correlated with genes controlling β-cell mass and function. Plasma triacylglycerols correlated with genes controlling liver β-oxidation. In humans, triacylglycerols also correlated with key regulators of insulin secretion. Mouse and human data identified PITPNC1 as a candidate regulator of insulin secretion. Triacylglycerols are biomarkers of the liver-to-β-cell axis and β-cell function.
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Affiliation(s)
- Ana Rodríguez Sánchez-Archidona
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Vital-IT Group, SIB Swiss Institute for Bioinformatics, 1015 Lausanne, Switzerland.
| | | | - Clara Roujeau
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Leonore Wigger
- Vital-IT Group, SIB Swiss Institute for Bioinformatics, 1015 Lausanne, Switzerland.
| | | | - Jessica Denom
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France.
| | - Marko Barovic
- Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, Dresden, Germany.
| | - Nadim Kassis
- Université de Paris, BFA, UMR 8251, CNRS, F-75013 Paris, France.
| | - Florence Mehl
- Vital-IT Group, SIB Swiss Institute for Bioinformatics, 1015 Lausanne, Switzerland.
| | - Jurgen Weitz
- Department of Visceral, Thoracic and Vascular Surgery, University Hospital, TU Dresden, Dresden, Germany.
| | - Marius Distler
- Department of Visceral, Thoracic and Vascular Surgery, University Hospital, TU Dresden, Dresden, Germany.
| | | | | | - Mark Ibberson
- Vital-IT Group, SIB Swiss Institute for Bioinformatics, 1015 Lausanne, Switzerland.
| | - Michele Solimena
- Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, Dresden, Germany.
| | | | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
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12
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Homolak J, Babic Perhoc A, Knezovic A, Osmanovic Barilar J, Salkovic-Petrisic M. Failure of the Brain Glucagon-Like Peptide-1-Mediated Control of Intestinal Redox Homeostasis in a Rat Model of Sporadic Alzheimer's Disease. Antioxidants (Basel) 2021; 10:1118. [PMID: 34356351 PMCID: PMC8301063 DOI: 10.3390/antiox10071118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 02/06/2023] Open
Abstract
The gastrointestinal system may be involved in the etiopathogenesis of the insulin-resistant brain state (IRBS) and Alzheimer's disease (AD). Gastrointestinal hormone glucagon-like peptide-1 (GLP-1) is being explored as a potential therapy as activation of brain GLP-1 receptors (GLP-1R) exerts neuroprotection and controls peripheral metabolism. Intracerebroventricular administration of streptozotocin (STZ-icv) is used to model IRBS and GLP-1 dyshomeostasis seems to be involved in the development of neuropathological changes. The aim was to explore (i) gastrointestinal homeostasis in the STZ-icv model (ii) assess whether the brain GLP-1 is involved in the regulation of gastrointestinal redox homeostasis and (iii) analyze whether brain-gut GLP-1 axis is functional in the STZ-icv animals. Acute intracerebroventricular treatment with exendin-3(9-39)amide was used for pharmacological inhibition of brain GLP-1R in the control and STZ-icv rats, and oxidative stress was assessed in plasma, duodenum and ileum. Acute inhibition of brain GLP-1R increased plasma oxidative stress. TBARS were increased, and low molecular weight thiols (LMWT), protein sulfhydryls (SH), and superoxide dismutase (SOD) were decreased in the duodenum, but not in the ileum of the controls. In the STZ-icv, TBARS and CAT were increased, LMWT and SH were decreased at baseline, and no further increment of oxidative stress was observed upon central GLP-1R inhibition. The presented results indicate that (i) oxidative stress is increased in the duodenum of the STZ-icv rat model of AD, (ii) brain GLP-1R signaling is involved in systemic redox regulation, (iii) brain-gut GLP-1 axis regulates duodenal, but not ileal redox homeostasis, and iv) brain-gut GLP-1 axis is dysfunctional in the STZ-icv model.
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Affiliation(s)
- Jan Homolak
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Ana Babic Perhoc
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Ana Knezovic
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Melita Salkovic-Petrisic
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
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13
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Zhang H, Liu Y, Cheng L, Ma X, Luo X. Exendin-4 induces a novel extended effect of ischemic tolerance via crosstalk with IGF-1R. Brain Res Bull 2020; 169:145-155. [PMID: 33197537 DOI: 10.1016/j.brainresbull.2020.11.008] [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: 03/19/2020] [Revised: 10/09/2020] [Accepted: 11/11/2020] [Indexed: 11/15/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) agonist exendin-4 (Ex-4), a drug that has been used in the clinical treatment of type 2 diabetes mellitus, also confers a neuroprotective effect against stroke. Although GLP-1 analogs were reported to induce sustained insulin secretion and glucose tolerance improved after cessation of treatment, no study has revealed whether Ex-4 exerts sustained neuroprotection against stroke and the underlying mechanism after treatment cessation. In this study, mice were pretreated with Ex-4 for 7 days, and middle cerebral artery occlusion (MCAO) was performed on different days after cessation of Ex-4 treatment. Ex-4 ameliorated neurological dysfunction and reduced the infarct volume induced by MCAO. These protective effects lasted for 6 days after the cessation of Ex-4 treatment and were associated with sustained upregulation of PI3K, AKT, mTOR, and HIF-1α levels, as well as HIF-1α downstream genes. Knockdown of GLP-1R or HIF-1α in the brain by short hairpin RNA abolished Ex-4 treatment-mediated neuroprotection. In normal mice, Ex-4 treatment led to instant upregulation of p-PI3K, p-AKT, p-mTOR, and HIF-1α expression levels, which quickly returned to normal after cessation of Ex-4 treatment, while the expression levels of insulin growth factor-1 receptor (IGF-1R) remained high for 6 days after Ex-4 cessation. Additionally, Ex-4 did not directly induce IGF-1 production, which was only induced by MCAO. Ex-4 induces extended cerebral ischemic tolerance. This neuroprotective effect is associated with activation of GLP-1R and upregulation of IGF-1R in the brain, and the latter then activates the PI3K/AKT/mTOR/HIF-1 signaling pathway via binding to IGF-1 secreted from the ischemic brain.
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Affiliation(s)
- Huinan Zhang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Xi'an, China
| | - Yunhan Liu
- Department of Neurology Impatient, the Second Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Liusiyuan Cheng
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Xi'an, China
| | - Xue Ma
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Xi'an, China.
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Xi'an, China.
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14
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Ebbesen M, Enevold C, Juul A, Heilmann C, Sengeløv H, Müller K. Insulin-Like Growth Factor Gene Polymorphisms Predict Clinical Course in Allogeneic Hematopoietic Stem Cell Transplantation. Front Immunol 2020; 11:1646. [PMID: 32793242 PMCID: PMC7393983 DOI: 10.3389/fimmu.2020.01646] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/19/2020] [Indexed: 12/27/2022] Open
Abstract
Allogeneic hematopoietic stem cell transplantation (HSCT) is challenged by significant toxicities that are propagated by systemic inflammation caused by cytotoxic damage. Insulin-like growth factor-1 (IGF-1) is key in repair of most tissues and is to a large extent genetically determined. We investigated eight single nucleotide polymorphisms (SNPs) in the genes encoding IGF-1 and its binding protein (IGFBP3) in 543 patients undergoing HSCT to access their impact on systemic inflammation and clinical outcomes. Overall, median serum levels of both IGF-1 and IGFBP3 were found reduced from the referral until 2 years post-HSCT compared with healthy sex- and age-matched individuals, but, for individuals homozygous of the known high-producer minor allele of rs1520220 (IGF1), rs978458 (IGF1), or rs2854744 (IGFBP3) serum levels remained normal during the whole period. In accordance, maximum C-reactive protein levels were lower for these genotypes of IGF1 (rs1520220: median 66 vs. 102 mg/L, P = 0.005 and rs978458: 53 vs. 104 mg/L, P < 0.001), translating into borderline significant superior survival (P = 0.060 for rs1520220) and reduced treatment-related mortality (P = 0.050 for rs978458). In conclusion, we found that three SNPs in the IGF-1 axis with known functional impact were associated with circulating IGF-1 or IGFBP-3 levels also in the setting of HSCT, and predictive of the severity of the toxic-inflammatory response during the treatment.
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Affiliation(s)
- Maria Ebbesen
- Department of Pediatrics and Adolescent Medicine, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Christian Enevold
- Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Anders Juul
- Department of Growth and Reproduction, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Carsten Heilmann
- Department of Pediatrics and Adolescent Medicine, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Henrik Sengeløv
- Department of Hematology, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Klaus Müller
- Department of Pediatrics and Adolescent Medicine, University Hospital Rigshospitalet, Copenhagen, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, University Hospital Rigshospitalet, Copenhagen, Denmark
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Alavi SE, Cabot PJ, Yap GY, Moyle PM. Optimized Methods for the Production and Bioconjugation of Site-Specific, Alkyne-Modified Glucagon-like Peptide-1 (GLP-1) Analogs to Azide-Modified Delivery Platforms Using Copper-Catalyzed Alkyne–Azide Cycloaddition. Bioconjug Chem 2020; 31:1820-1834. [DOI: 10.1021/acs.bioconjchem.0c00291] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Seyed Ebrahim Alavi
- School of Pharmacy, The University of Queensland, 20 Cornwall Street, Woolloongabba, Queensland 4102, Australia
| | - Peter John Cabot
- School of Pharmacy, The University of Queensland, 20 Cornwall Street, Woolloongabba, Queensland 4102, Australia
| | - Gee Yi Yap
- School of Pharmacy, The University of Queensland, 20 Cornwall Street, Woolloongabba, Queensland 4102, Australia
| | - Peter Michael Moyle
- School of Pharmacy, The University of Queensland, 20 Cornwall Street, Woolloongabba, Queensland 4102, Australia
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16
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Abstract
The discovery that glucagon-like peptide 1 (GLP-1) mediates a significant proportion of the incretin effect during the postprandial period and the subsequent observation that GLP-1 bioactivity is retained in type 2 diabetes (T2D) led to new therapeutic strategies being developed for T2D treatment based on GLP-1 action. Although owing to its short half-life exogenous GLP-1 has no use therapeutically, GLP-1 mimetics, which have a much longer half-life than native GLP-1, have proven to be effective for T2D treatment since they prolong the incretin effect in patients. These GLP-1 mimetics are a desirable therapeutic option for T2D since they do not provoke hypoglycaemia or weight gain and have simple modes of administration and monitoring. Additionally, over more recent years, GLP-1 action has been found to mediate systemic physiological beneficial effects and this has high clinical relevance due to the post-diagnosis complications of T2D. Indeed, recent studies have found that certain GLP-1 analogue therapies improve the cardiovascular outcomes for people with diabetes. Furthermore, GLP-1-based therapies may enable new therapeutic strategies for diseases that can also arise independently of the clinical manifestation of T2D, such as dementia and Parkinson's disease. GLP-1 functions by binding to its receptor (GLP-1R), which expresses mainly in pancreatic islet beta cells. A better understanding of the mechanisms and signalling pathways by which acute and chronic GLP-1R activation alleviates disease phenotypes and induces desirable physiological responses during healthy conditions will likely lead to the development of new therapeutic GLP-1 mimetic-based therapies, which improve prognosis to a greater extent than current therapies for an array of diseases.
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Affiliation(s)
- Josh Reed
- Institute of Life Science, Medical School, Swansea University, Swansea, Wales, SA2 8PP, UK
| | - Stephen C. Bain
- Institute of Life Science, Medical School, Swansea University, Swansea, Wales, SA2 8PP, UK
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17
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Dumayne C, Tarussio D, Sanchez-Archidona AR, Picard A, Basco D, Berney XP, Ibberson M, Thorens B. Klf6 protects β-cells against insulin resistance-induced dedifferentiation. Mol Metab 2020; 35:100958. [PMID: 32244185 PMCID: PMC7093812 DOI: 10.1016/j.molmet.2020.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/30/2020] [Accepted: 02/02/2020] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES In the pathogenesis of type 2 diabetes, development of insulin resistance triggers an increase in pancreatic β-cell insulin secretion capacity and β-cell number. Failure of this compensatory mechanism is caused by a dedifferentiation of β-cells, which leads to insufficient insulin secretion and diabetic hyperglycemia. The β-cell factors that normally protect against dedifferentiation remain poorly defined. Here, through a systems biology approach, we identify the transcription factor Klf6 as a regulator of β-cell adaptation to metabolic stress. METHODS We used a β-cell specific Klf6 knockout mouse model to investigate whether Klf6 may be a potential regulator of β-cell adaptation to a metabolic stress. RESULTS We show that inactivation of Klf6 in β-cells blunts their proliferation induced by the insulin resistance of pregnancy, high-fat high-sucrose feeding, and insulin receptor antagonism. Transcriptomic analysis showed that Klf6 controls the expression of β-cell proliferation genes and, in the presence of insulin resistance, it prevents the down-expression of genes controlling mature β-cell identity and the induction of disallowed genes that impair insulin secretion. Its expression also limits the transdifferentiation of β-cells into α-cells. CONCLUSION Our study identifies a new transcription factor that protects β-cells against dedifferentiation, and which may be targeted to prevent diabetes development.
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Affiliation(s)
- Christopher Dumayne
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Ana Rodriguez Sanchez-Archidona
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
| | - Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Davide Basco
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Xavier Pascal Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Mark Ibberson
- Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
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18
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Khan R, Tomas A, Rutter GA. Effects on pancreatic Beta and other Islet cells of the glucose-dependent insulinotropic polypeptide. Peptides 2020; 125:170201. [PMID: 31751656 DOI: 10.1016/j.peptides.2019.170201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/11/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gut-derived incretin that, in common with glucagon-like peptide-1 (GLP-1), has both insulin releasing and extra-pancreatic glucoregulatory actions. GIP is released in response to glucose or fat absorption and acts on the GIP receptor (GIPR) to potentiate insulin release from pancreatic beta cells. GIP has also been shown to promote beta cell survival and stimulate the release of GLP-1 from islet alpha cells. There is now evidence to suggest that low levels of GIP are secreted from alpha cells and may act in a paracrine manner to prime neighboring beta cells for insulin release. In addition, GIP acts on adipocytes to stimulate fat storage and can exert anorexigenic effects via actions in the hypothalamus. Contrary to GLP-1, the development of effective GIP-based T2D treatments has been hindered by poor bioavailability and attenuation of beta cell responses to GIP in some patients with sub-optimally controlled T2D. Recently, longer-acting GIP agonists that exhibit enzymatic stability, as well as dual GLP-1/GIP agonists which provide simultaneous improvement in glucose and weight control have been generated and successfully tested in animal T2D models. This, together with reports on GIP antagonists that may protect against obesity, has revived the interest on the GIP/GIPR axis as a potential anti-diabetic pathway. In this review, we summarize the known aspects of the effects of GIP on beta and other islet cells and discuss the most recent developments on GIP-based therapeutic agents for the improvement of beta cell function in T2D patients.
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Affiliation(s)
- Rabeet Khan
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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Brial F, Alzaid F, Sonomura K, Kamatani Y, Meneyrol K, Le Lay A, Péan N, Hedjazi L, Sato TA, Venteclef N, Magnan C, Lathrop M, Dumas ME, Matsuda F, Zalloua P, Gauguier D. The Natural Metabolite 4-Cresol Improves Glucose Homeostasis and Enhances β-Cell Function. Cell Rep 2020; 30:2306-2320.e5. [PMID: 32075738 DOI: 10.1016/j.celrep.2020.01.066] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 10/26/2019] [Accepted: 01/22/2020] [Indexed: 02/09/2023] Open
Abstract
Exposure to natural metabolites contributes to the risk of cardiometabolic diseases (CMDs). Through metabolome profiling, we identify the inverse correlation between serum concentrations of 4-cresol and type 2 diabetes. The chronic administration of non-toxic doses of 4-cresol in complementary preclinical models of CMD reduces adiposity, glucose intolerance, and liver triglycerides, enhances insulin secretion in vivo, stimulates islet density and size, and pancreatic β-cell proliferation, and increases vascularization, suggesting activated islet enlargement. In vivo insulin sensitivity is not affected by 4-cresol. The incubation of mouse isolated islets with 4-cresol results in enhanced insulin secretion, insulin content, and β-cell proliferation of a magnitude similar to that induced by GLP-1. In both CMD models and isolated islets, 4-cresol is associated with the downregulated expression of the kinase DYRK1A, which may mediate its biological effects. Our findings identify 4-cresol as an effective regulator of β-cell function, which opens up perspectives for therapeutic applications in syndromes of insulin deficiency.
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Affiliation(s)
- Francois Brial
- Université de Paris, INSERM UMR 1124, 75006 Paris, France
| | - Fawaz Alzaid
- Sorbonne Université, Université Paris Descartes, INSERM UMR_S 1138, Cordeliers Research Centre, 75006 Paris, France
| | - Kazuhiro Sonomura
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan; Life Science Research Center, Technology Research Laboratory, Shimadzu, Kyoto 604-8511, Japan
| | - Yoichiro Kamatani
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Kelly Meneyrol
- Université de Paris, Unit of Functional and Adaptive Biology, UMR 8251, CNRS, 4 rue Marie Andrée Lagroua Weill-Halle, 75013 Paris, France
| | - Aurélie Le Lay
- Université de Paris, INSERM UMR 1124, 75006 Paris, France
| | - Noémie Péan
- Université de Paris, INSERM UMR 1124, 75006 Paris, France
| | | | - Taka-Aki Sato
- Life Science Research Center, Technology Research Laboratory, Shimadzu, Kyoto 604-8511, Japan
| | - Nicolas Venteclef
- Sorbonne Université, Université Paris Descartes, INSERM UMR_S 1138, Cordeliers Research Centre, 75006 Paris, France
| | - Christophe Magnan
- Université de Paris, Unit of Functional and Adaptive Biology, UMR 8251, CNRS, 4 rue Marie Andrée Lagroua Weill-Halle, 75013 Paris, France
| | - Mark Lathrop
- McGill University and Genome Quebec Innovation Centre, 740 Doctor Penfield Avenue, Montreal, QC H3A 0G1, Canada
| | - Marc-Emmanuel Dumas
- Imperial College London, Section of Biomolecular Medicine, Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Sir Alexander Fleming Building, London SW7 2AZ, UK
| | - Fumihiko Matsuda
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Pierre Zalloua
- Lebanese American University, School of Medicine, Beirut 1102 2801, Lebanon.
| | - Dominique Gauguier
- Université de Paris, INSERM UMR 1124, 75006 Paris, France; Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan; McGill University and Genome Quebec Innovation Centre, 740 Doctor Penfield Avenue, Montreal, QC H3A 0G1, Canada.
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Ježek P, Jabůrek M, Plecitá-Hlavatá L. Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes. Antioxid Redox Signal 2019; 31:722-751. [PMID: 30450940 PMCID: PMC6708273 DOI: 10.1089/ars.2018.7656] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022]
Abstract
Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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21
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Cardioprotective Mechanisms of Exenatide in Isoprenaline-induced Myocardial Infarction: Novel Effects on Myocardial α-Estrogen Receptor Expression and IGF-1/IGF-2 System. J Cardiovasc Pharmacol 2019; 71:160-173. [PMID: 29256971 DOI: 10.1097/fjc.0000000000000557] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Myocardial infarction (MI) is one of the main causes of morbidity and mortality in diabetic patients. The antidiabetic glucagon-like polypeptide-1 receptor (GLP-1R) agonists, such as exenatide, proved to confer cardioprotection; however, their exact mechanisms are not fully elucidated. Although the cardioprotective effect of α-estrogen receptor (ERα) activation is well established, its involvement in exenatide-induced cardioprotection has never been investigated. Moreover, modulation of insulin-like growth factor-1/2 (IGF-1/IGF-2) system by exenatide, and the consequent effect on cardiomyocyte apoptosis, is yet to be established. Current study aimed to investigate the cardioprotective potential of exenatide versus the standard cardioprotective agent, 17β-estradiol, against isoprenaline (ISO)-induced MI in rats. MI-insulted group showed electrocardiographic abnormalities, elevated serum cardiac markers, higher serum IGF-2 level along with histopathological abnormalities. Treatment with exenatide and/or 17β-estradiol, commenced 8 weeks before ISO insult, ameliorated these anomalies with maximum cardioprotection achieved with combined treatment. This was associated with upregulation of both ERα and IGF-1R, and downregulation of IGF-2R in left ventricles. Inhibition of ERs in Langendorff preparations confirmed their involvement in mediating exenatide-induced cardioprotective effect. Current study showed that the GLP-1R agonist exenatide exerted cardioprotection associated with upregulation of ERα and modulation of IGF-1/IGF-2 signaling in favor of antiapoptosis.
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22
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Tse LH, Wong YH. GPCRs in Autocrine and Paracrine Regulations. Front Endocrinol (Lausanne) 2019; 10:428. [PMID: 31354618 PMCID: PMC6639758 DOI: 10.3389/fendo.2019.00428] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/14/2019] [Indexed: 12/17/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest superfamily of integral membrane protein receptors. As signal detectors, the several 100 known GPCRs are responsible for sensing the plethora of endogenous ligands that are critical for the functioning of our endocrine system. Although GPCRs are typically considered as detectors for first messengers in classical signal transduction pathways, they seldom operate in isolation in complex biological systems. Intercellular communication between identical or different cell types is often mediated by autocrine or paracrine signals that are generated upon activation of specific GPCRs. In the context of energy homeostasis, the distinct complement of GPCRs in each cell type bridges the autocrine and paracrine communication within an organ, and the various downstream signaling mechanisms regulated by GPCRs can be integrated in a cell to produce an ultimate output. GPCRs thus act as gatekeepers that coordinate and fine-tune a response. By examining the role of GPCRs in activating and receiving autocrine and paracrine signals, one may have a better understanding of endocrine diseases that are associated with GPCR mutations, thereby providing new insights for treatment regimes.
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Affiliation(s)
- Lap Hang Tse
- Division of Life Science, Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Yung Hou Wong
- Division of Life Science, Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
- State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
- *Correspondence: Yung Hou Wong
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23
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Rowlands J, Heng J, Newsholme P, Carlessi R. Pleiotropic Effects of GLP-1 and Analogs on Cell Signaling, Metabolism, and Function. Front Endocrinol (Lausanne) 2018; 9:672. [PMID: 30532733 PMCID: PMC6266510 DOI: 10.3389/fendo.2018.00672] [Citation(s) in RCA: 159] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/29/2018] [Indexed: 12/22/2022] Open
Abstract
The incretin hormone Glucagon-Like Peptide-1 (GLP-1) is best known for its "incretin effect" in restoring glucose homeostasis in diabetics, however, it is now apparent that it has a broader range of physiological effects in the body. Both in vitro and in vivo studies have demonstrated that GLP-1 mimetics alleviate endoplasmic reticulum stress, regulate autophagy, promote metabolic reprogramming, stimulate anti-inflammatory signaling, alter gene expression, and influence neuroprotective pathways. A substantial body of evidence has accumulated with respect to how GLP-1 and its analogs act to restore and maintain normal cellular functions. These findings have prompted several clinical trials which have reported GLP-1 analogs improve cardiac function, restore lung function and reduce mortality in patients with obstructive lung disease, influence blood pressure and lipid storage, and even prevent synaptic loss and neurodegeneration. Mechanistically, GLP-1 elicits its effects via acute elevation in cAMP levels, and subsequent protein kinase(s) activation, pathways well-defined in pancreatic β-cells which stimulate insulin secretion in conjunction with elevated Ca2+ and ATP. More recently, new studies have shed light on additional downstream pathways stimulated by chronic GLP-1 exposure, findings which have direct relevance to our understanding of the potential therapeutic effects of longer lasting analogs recently developed for clinical use. In this review, we provide a comprehensive description of the diverse roles for GLP-1 across multiple tissues, describe downstream pathways stimulated by acute and chronic exposure, and discuss novel pleiotropic applications of GLP-1 mimetics in the treatment of human disease.
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Affiliation(s)
| | | | - Philip Newsholme
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, WA, Australia
| | - Rodrigo Carlessi
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute, Perth, WA, Australia
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24
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Rowlands J, Cruzat V, Carlessi R, Newsholme P. Insulin and IGF-1 receptor autocrine loops are not required for Exendin-4 induced changes to pancreatic β-cell bioenergetic parameters and metabolism in BRIN-BD11 cells. Peptides 2018; 100:140-149. [PMID: 29412813 DOI: 10.1016/j.peptides.2017.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/23/2017] [Accepted: 11/23/2017] [Indexed: 01/13/2023]
Abstract
Pharmacological long lasting Glucagon-like peptide-1 (GLP-1) analogues, such as Exendin-4, have become widely used diabetes therapies. Chronic GLP-1R stimulation has been linked to β-cell protection and these pro-survival actions of GLP-1 are dependent on the activation of the mammalian target of rapamycin (mTOR) leading to accumulation of Hypoxia inducible factor 1 alpha (HIF-1α). Recent studies from our lab indicate that prolonged GLP-1R stimulation promotes metabolic reprograming of β-cells towards a highly glycolytic phenotype and activation of the mTOR/HIF-1α pathway was required for this action. We hypothesised that GLP-1 induced metabolic changes depend on the activation of mTOR and HIF-1α, in a cascade that occurs after triggering of a potential Insulin-like growth factor 1 receptor (IGF-1R) or the Insulin receptor (IR) autocrine loops. Loss of function of these receptors, through the use of small interfering RNA, or neutralizing antibodies directed towards their products, was undertaken in conjunction with functional assays. Neither of these strategies mitigated the effect of GLP-1 on glucose uptake, protein expression or bioenergetic flux. Our data indicates that activation of IGF-1R and/or the IR autocrine loops resulting in β-cell protection and function, involve mechanisms independent to the enhanced metabolic effects resulting from sustained GLP-1R activation.
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Affiliation(s)
- Jordan Rowlands
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University Bldg 305, Rm 135 - CHIRI, Kent St, Bentley, WA, 6102, Australia.
| | - Vinicius Cruzat
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University Bldg 305, Rm 135 - CHIRI, Kent St, Bentley, WA, 6102, Australia.
| | - Rodrigo Carlessi
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University Bldg 305, Rm 135 - CHIRI, Kent St, Bentley, WA, 6102, Australia.
| | - Philip Newsholme
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University Bldg 305, Rm 135 - CHIRI, Kent St, Bentley, WA, 6102, Australia.
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Kheder MH, Bailey SR, Dudley KJ, Sillence MN, de Laat MA. Equine glucagon-like peptide-1 receptor physiology. PeerJ 2018; 6:e4316. [PMID: 29404215 PMCID: PMC5793710 DOI: 10.7717/peerj.4316] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/11/2018] [Indexed: 12/12/2022] Open
Abstract
Background Equine metabolic syndrome (EMS) is associated with insulin dysregulation, which often manifests as post-prandial hyperinsulinemia. Circulating concentrations of the incretin hormone, glucagon-like peptide-1 (GLP-1) correlate with an increased insulin response to carbohydrate intake in animals with EMS. However, little is known about the equine GLP-1 receptor (eGLP-1R), or whether GLP-1 concentrations can be manipulated. The objectives were to determine (1) the tissue localisation of the eGLP-1R, (2) the GLP-1 secretory capacity of equine intestine in response to glucose and (3) whether GLP-1 stimulated insulin secretion from isolated pancreatic islets can be attenuated. Methods Archived and abattoir-sourced tissues from healthy horses were used. Reverse transcriptase PCR was used to determine the tissue distribution of the eGLP-1R gene, with immunohistochemical confirmation of its pancreatic location. The GLP-1 secretion from intestinal explants in response to 4 and 12 mM glucose was quantified in vitro. Pancreatic islets were freshly isolated to assess the insulin secretory response to GLP-1 agonism and antagonism in vitro, using concentration-response experiments. Results The eGLP-1R gene is widely distributed in horses (pancreas, heart, liver, kidney, duodenum, digital lamellae, tongue and gluteal skeletal muscle). Within the pancreas the eGLP-1R was immunolocalised to the pancreatic islets. Insulin secretion from pancreatic islets was concentration-dependent with human GLP-1, but not the synthetic analogue exendin-4. The GLP-1R antagonist exendin 9-39 (1 nM) reduced (P = 0.08) insulin secretion by 27%. Discussion The distribution of the eGLP-1R across a range of tissues indicates that it may have functions beyond insulin release. The ability to reduce insulin secretion, and therefore hyperinsulinemia, through eGLP-1R antagonism is a promising and novel approach to managing equine insulin dysregulation.
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Affiliation(s)
- Murad H Kheder
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Simon R Bailey
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Kevin J Dudley
- Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Martin N Sillence
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Melody A de Laat
- Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
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Maciejewski BS, Manion TB, Steppan CM. Pharmacological inhibition of diacylglycerol acyltransferase-1 and insights into postprandial gut peptide secretion. World J Gastrointest Pathophysiol 2017; 8:161-175. [PMID: 29184702 PMCID: PMC5696614 DOI: 10.4291/wjgp.v8.i4.161] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 07/25/2017] [Accepted: 09/04/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To examine the role that enzyme Acyl-CoA:diacylglycerol acyltransferase-1 (DGAT1) plays in postprandial gut peptide secretion and signaling.
METHODS The standard experimental paradigm utilized to evaluate the incretin response was a lipid challenge. Following a lipid challenge, plasma was collected via cardiac puncture at each time point from a cohort of 5-8 mice per group from baseline at time zero to 10 h. Incretin hormones [glucagon like peptide-1 (GLP-1), peptide tyrosine-tyrosine (PYY) and glucose dependent insulinotropic polypeptide (GIP)] were then quantitated. The impact of pharmacological inhibition of DGAT1 on the incretin effect was evaluated in WT mice. Additionally, a comparison of loss of DGAT1 function either by genetic ablation or pharmacological inhibition. To further elucidate the pathways and mechanisms involved in the incretin response to DGAT1 inhibition, other interventions [inhibitors of dipeptidyl peptidase-IV (sitagliptin), pancreatic lipase (Orlistat), GPR119 knockout mice] were evaluated.
RESULTS DGAT1 deficient mice and wildtype C57/BL6J mice were lipid challenged and levels of both active and total GLP-1 in the plasma were increased. This response was further augmented with DGAT1 inhibitor PF-04620110 treated wildtype mice. Furthermore, PF-04620110 was able to dose responsively increase GLP-1 and PYY, but blunt GIP at all doses of PF-04620110 during lipid challenge. Combination treatment of PF-04620110 and Sitagliptin in wildtype mice during a lipid challenge synergistically enhanced postprandial levels of active GLP-1. In contrast, in a combination study with Orlistat, the ability of PF-04620110 to elicit an enhanced incretin response was abrogated. To further explore this observation, GPR119 knockout mice were evaluated. In response to a lipid challenge, GPR119 knockout mice exhibited no increase in active or total GLP-1 and PYY. However, PF-04620110 was able to increase total GLP-1 and PYY in GPR119 knockout mice as compared to vehicle treated wildtype mice.
CONCLUSION Collectively, these data provide some insight into the mechanism by which inhibition of DGAT1 enhances intestinal hormone release.
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Affiliation(s)
- Benjamin S Maciejewski
- Pfizer Worldwide Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA 02139, United States
| | - Tara B Manion
- Pfizer Worldwide Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA 02139, United States
| | - Claire M Steppan
- Pfizer Worldwide Research and Development, Cardiovascular and Metabolic Diseases Research Unit, Cambridge, MA 02139, United States
- Pfizer Inc., Groton, CT 06340, United States
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GLP-1 and IGF-I levels are elevated in late infancy in low birth weight infants, independently of GLP-1 receptor polymorphisms and neonatal nutrition. Int J Obes (Lond) 2017; 42:915-918. [PMID: 29089613 DOI: 10.1038/ijo.2017.271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 10/05/2017] [Accepted: 10/16/2017] [Indexed: 01/26/2023]
Abstract
Low birth weight followed by rapid postnatal weight gain is associated with increased risks for obesity and diabetes in adulthood. Modulation of glucagon-like-peptide 1 (GLP-1) secretion by (epi)genetic mechanisms or nutrition may, in part, influence this risk. Formula-fed infants born small-for-gestational-age (SGA) have higher circulating GLP-1 at age 4 months than breastfed SGA or appropriate-for-gestational-age (AGA) infants. Here we assessed GLP-1 concentrations in healthy AGA (n=149) and SGA (n=107) subjects at age 12 months and their association with endocrine-metabolic and body composition parameters and GLP-1 receptor (GLP-1R) rs6923761 and rs3765467 polymorphisms. At birth, cord GLP-1 concentrations were comparable in AGA and SGA infants. At age 12 months, insulin-like growth factor I (IGF-I) and GLP-1 levels were higher than at birth; SGA infants displayed higher IGF-I and GLP-1 concentrations than AGA infants (both P<0.001) that were unrelated to neonatal nutrition or GLP-1R genotype and that were paralleled by a significant increase in weight Z-score (P<0.001 vs AGA). In conclusion, SGA infants have augmented IGF-I and prefeeding GLP-1 concentrations in late infancy. Increased GLP-1 levels may impair hypothalamic and/or peripheral GLP-1R signaling, exert long-term negative effects on the hypothalamic nuclei regulating energy homeostasis and increase the risks for obesity and diabetes.
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Santilli F, Simeone PG, Guagnano MT, Leo M, Maccarone MT, Di Castelnuovo A, Sborgia C, Bonadonna RC, Angelucci E, Federico V, Cianfarani S, Manzoli L, Davì G, Tartaro A, Consoli A. Effects of Liraglutide on Weight Loss, Fat Distribution, and β-Cell Function in Obese Subjects With Prediabetes or Early Type 2 Diabetes. Diabetes Care 2017; 40:1556-1564. [PMID: 28912305 DOI: 10.2337/dc17-0589] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 08/21/2017] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Obesity is associated with an increased risk of type 2 diabetes and cardiovascular complications. The risk depends significantly on adipose tissue distribution. Liraglutide, a glucagon-like peptide 1 analog, is associated with weight loss, improved glycemic control, and reduced cardiovascular risk. We determined whether an equal degree of weight loss by liraglutide or lifestyle changes has a different impact on subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in obese subjects with prediabetes or early type 2 diabetes. RESEARCH DESIGN AND METHODS Sixty-two metformin-treated obese subjects with prediabetes or newly diagnosed type 2 diabetes, were randomized to liraglutide (1.8 mg/day) or lifestyle counseling. Changes in SAT and VAT levels (determined by abdominal MRI), insulin sensitivity (according to the Matsuda index), and β-cell function (β-index) were assessed during a multiple-sampling oral glucose tolerance test; and circulating levels of IGF-I and IGF-II were assessed before and after a comparable weight loss (7% of initial body weight). RESULTS After comparable weight loss, achieved by 20 patients per arm, and superimposable glycemic control, as reflected by HbA1c level (P = 0.60), reduction in VAT was significantly higher in the liraglutide arm than in the lifestyle arm (P = 0.028), in parallel with a greater improvement in β-index (P = 0.021). No differences were observed in SAT reduction (P = 0.64). IGF-II serum levels were significantly increased (P = 0.024) only with liraglutide administration, and the increase in IGF-II levels correlated with both a decrease in VAT (ρ = -0.435, P = 0.056) and an increase in the β-index (ρ = 0.55, P = 0.012). CONCLUSIONS Liraglutide effects on visceral obesity and β-cell function might provide a rationale for using this molecule in obese subjects in an early phase of glucose metabolism dysregulation natural history.
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Affiliation(s)
- Francesca Santilli
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Paola G Simeone
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Maria T Guagnano
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Marika Leo
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Marica T Maccarone
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Augusto Di Castelnuovo
- Department of Epidemiology and Prevention, Istituto di Ricovero e Cura a Carattere Scientifico Istituto Neurologico Mediterraneo, Pozzilli, Italy
| | - Cristina Sborgia
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Riccardo C Bonadonna
- Department of Clinical and Experimental Medicine, University of Parma, and Division of Endocrinology, Azienda Ospedaliera-Universitaria di Parma, Parma, Italy
| | - Ermanno Angelucci
- Department of Clinica Medica, "SS. Annunziata" Chieti Hospital, Chieti, Italy
| | - Virginia Federico
- Department of Clinical Pathology, "SS. Annunziata" Chieti Hospital, Chieti, Italy
| | - Stefano Cianfarani
- Dipartimento Pediatrico Universitario Ospedaliero, "Bambino Gesù" Children's Hospital-Tor Vergata University, Rome, Italy.,Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Lamberto Manzoli
- Department of Medicine Sciences, University of Ferrara, Ferrara, Italy
| | - Giovanni Davì
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Armando Tartaro
- Department of Neuroscience, Imaging and Clinical Sciences, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Agostino Consoli
- Department of Medicine and Aging, and Center of Aging Science and Translational Medicine (CESI-Met), "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
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Zhang Y, Deng R, Yang X, Xu W, Liu Y, Li F, Zhang J, Tang H, Ji X, Bi Y, Wang X, Zhou L, Ning G. Glucose potentiates β-cell function by inducing Tph1 expression in rat islets. FASEB J 2017; 31:5342-5355. [PMID: 28794173 DOI: 10.1096/fj.201700351r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/25/2017] [Indexed: 12/19/2022]
Abstract
Impaired pancreatic β-cell function is the primary defect in type 2 diabetes. Glucose is an important regulator of β-cell growth and function; however, the mechanisms that are involved in the chronic adaptation of β cells to hyperglycemia remain largely unknown. In the present study, global gene expression patterns revealed that tryptophan hydroxylase 1 (Tph1) was the most profound of genes that are up-regulated in rat islets exposed to high glucose. Calcium and cAMP signals synergistically mediated glucose-stimulated Tph1 transcription in β cells by activating cAMP-responsive element-binding protein and promoting its binding with a Tph1 promoter. Similar to in vitro results, in vivo infusion of high glucose also strongly induced Tph1 expression and serotonin production in rat islets, along with enhanced islet function. Inhibition or knockdown of Tph1 markedly decreased glucose-potentiated insulin secretion. In contrast, overexpression of Tph1 augmented glucose-stimulated insulin secretion in rat islets by up-regulating the expression of genes that are related to islet function. In addition, the long-acting glucagon-like peptide 1 receptor agonist, exendin-4, stimulated Tph1 expression in a glucose-dependent manner. Knockdown of Tph1 inhibited exendin-4-potentiated insulin secretion in rat islets. These findings suggest that Tph1 mediates the compensation of islet function induced by glucose, and that promoting Tph1 expression in pancreatic β cells will provide a new strategy for the treatment of type 2 diabetes mellitus.-Zhang, Y., Deng, R., Yang, X., Xu, W., Liu, Y., Li, F., Zhang, J., Tang, H., Ji, X., Bi, Y., Wang, X., Zhou, L., Ning, G. Glucose potentiates β-cell function by inducing Tph1 expression in rat islets.
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Affiliation(s)
- Yuqing Zhang
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ruyuan Deng
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xue Yang
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Wan Xu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yun Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fengying Li
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Juan Zhang
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Hongju Tang
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xueying Ji
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Yufang Bi
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Xiao Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Libin Zhou
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Guang Ning
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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Caporarello N, Parrino C, Trischitta V, Frittitta L. Insulin receptor signaling and glucagon-like peptide 1 effects on pancreatic beta cells. PLoS One 2017; 12:e0181190. [PMID: 28767692 PMCID: PMC5540605 DOI: 10.1371/journal.pone.0181190] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 06/26/2017] [Indexed: 12/03/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is a potent gluco-incretin hormone, which plays a central role on pancreatic beta cell proliferation, survival and insulin secreting activity and whose analogs are used for treating hyperglycemia in type 2 diabetes mellitus. Notably, abnormal insulin signaling affects all the above-mentioned aspects on pancreatic beta cells. The aim of our study was to investigate whether the protective effects of GLP1-1 on beta cells are affected by altered insulin receptor signaling. To this end, several effects of GLP-1 were studied in INS-1E rat beta cells transfected either with an inhibitor of insulin receptor function (i.e., the Ectonucleotide Pyrophosphatase Phosphodiesterase 1, ENPP1), or with insulin receptor small interfering RNA, as well as in control cells. Crucial experiments were carried out also in a second cell line, namely the βTC-1 mouse beta cells. Our data indicate that in insulin secreting beta cells in which either ENPP1 was up-regulated or insulin receptor was down-regulated, GLP-1 positive effects on several pancreatic beta cell activities, including glucose-induced insulin secretion, cell proliferation and cell survival, were strongly reduced. Further studies are needed to understand whether such a scenario occurs also in humans and, if so, if it plays a role of clinical relevance in diabetic patients with poor responsiveness to GLP-1 related treatments.
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Affiliation(s)
- Nunzia Caporarello
- Endocrine Unit, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Cristina Parrino
- Endocrine Unit, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Vincenzo Trischitta
- IRCCS Casa Sollievo della Sofferenza, Research Unit of Diabetes and Endocrine Diseases, San Giovanni Rotondo, Italy
- Department of Experimental Medicine “Sapienza” University, Rome, Italy
| | - Lucia Frittitta
- Endocrine Unit, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
- * E-mail:
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Muhammad AB, Xing B, Liu C, Naji A, Ma X, Simmons RA, Hua X. Menin and PRMT5 suppress GLP1 receptor transcript and PKA-mediated phosphorylation of FOXO1 and CREB. Am J Physiol Endocrinol Metab 2017; 313:E148-E166. [PMID: 28270438 PMCID: PMC5582886 DOI: 10.1152/ajpendo.00241.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 01/11/2017] [Accepted: 02/20/2017] [Indexed: 12/23/2022]
Abstract
Menin is a scaffold protein that interacts with several epigenetic mediators to regulate gene transcription, and suppresses pancreatic β-cell proliferation. Tamoxifen-inducible deletion of multiple endocrine neoplasia type 1 (MEN1) gene, which encodes the protein menin, increases β-cell mass in multiple murine models of diabetes and ameliorates diabetes. Glucagon-like-peptide-1 (GLP1) is another key physiological modulator of β-cell mass and glucose homeostasis. However, it is not clearly understood whether menin crosstalks with GLP1 signaling. Here, we show that menin and protein arginine methyltransferase 5 (PRMT5) suppress GLP1 receptor (GLP1R) transcript levels. Notably, a GLP1R agonist induces phosphorylation of forkhead box protein O1 (FOXO1) at S253, and the phosphorylation is mediated by PKA. Interestingly, menin suppresses GLP1-induced and PKA-mediated phosphorylation of both FOXO1 and cAMP response element binding protein (CREB), likely through a protein arginine methyltransferase. Menin-mediated suppression of FOXO1 and CREB phosphorylation increases FOXO1 levels and suppresses CREB target genes, respectively. A small-molecule menin inhibitor reverses menin-mediated suppression of both FOXO1 and CREB phosphorylation. In addition, ex vivo treatment of both mouse and human pancreatic islets with a menin inhibitor increases levels of proliferation marker Ki67. In conclusion, our results suggest that menin and PRMT5 suppress GLP1R transcript levels and PKA-mediated phosphorylation of FOXO1 and CREB, and a menin inhibitor may reverse this suppression to induce β-cell proliferation.
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Affiliation(s)
- Abdul Bari Muhammad
- Abramson Family Cancer Research Institute, Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Bowen Xing
- Shenzen University School of Medicine, Institute of Diabetes Research, Shenzhen, Guangdong, China
| | - Chengyang Liu
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ali Naji
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xiaosong Ma
- Shenzen University School of Medicine, Institute of Diabetes Research, Shenzhen, Guangdong, China
| | - Rebecca A Simmons
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Xianxin Hua
- Abramson Family Cancer Research Institute, Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania;
- Institute for Diabetes, Obesity, and Metabolism Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Kawamori D. Exploring the molecular mechanisms underlying α- and β-cell dysfunction in diabetes. Diabetol Int 2017; 8:248-256. [PMID: 30603330 PMCID: PMC6224887 DOI: 10.1007/s13340-017-0327-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 06/20/2017] [Indexed: 01/09/2023]
Abstract
Pancreatic islet dysfunction, including impaired insulin secretion in β cells and dysregulated glucagon secretion in α cells, is the chief pathology of diabetes. In β cells, oxidative stress, evoked by chronic hyperglycemia, was found to induce dysfunction of a critical transcription factor, PDX1, caused by its nucleocytoplasmic translocation via interactions with the insulin and JNK signaling pathways and another transcription factor, FOXO1. The significance of α-cell insulin signaling in the physiological and pathological regulation of α-cell biology was demonstrated in α-cell-specific insulin receptor knockout mice, which exhibited dysregulated glucagon secretion. Moreover, a high-glucose load directly induced excessive glucagon secretion in a glucagon-secreting cell line and isolated islets, together with impairment of insulin signaling. These findings indicate that disordered insulin signaling is central to the pathophysiology of islet dysfunction in both α and β cells. On the other hand, certain beneficial effects of GLP-1 on dysfunctional α and β cells indicate that it has therapeutic potential for diabetes patients who exhibit insulin resistance in islets. These studies, involving basic medical research approaches, have-at least in part-clarified the molecular mechanisms underlying α- and β-cell dysfunction in diabetes, and offer important clues that should aid the development of future therapeutic approaches to the disease.
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Affiliation(s)
- Dan Kawamori
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871 Japan
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Kawamori D, Shirakawa J, Liew CW, Hu J, Morioka T, Duttaroy A, Burkey B, Kulkarni RN. GLP-1 signalling compensates for impaired insulin signalling in regulating beta cell proliferation in βIRKO mice. Diabetologia 2017; 60:1442-1453. [PMID: 28526921 PMCID: PMC5508991 DOI: 10.1007/s00125-017-4303-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 04/18/2017] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS We aimed to investigate potential interactions between insulin and glucagon-like peptide (GLP)-1 signalling pathways in the regulation of beta cell-cycle dynamics in vivo, in the context of the therapeutic potential of GLP-1 to modulate impaired beta cell function. METHODS Beta cell-specific insulin receptor knockout (βIRKO) mice, which exhibit beta cell dysfunction and an age-dependent decrease in beta cell mass, were treated with the dipeptidyl peptidase-4 inhibitor vildagliptin. Following this, glucose homeostasis and beta cell proliferation were evaluated and underlying molecular mechanisms were investigated. RESULTS The sustained elevation in circulating GLP-1 levels, caused by treatment of the knockout mice with vildagliptin for 6 weeks, significantly improved glucose tolerance secondary to enhanced insulin secretion and proliferation of beta cells. Treating βIRKO beta cell lines with the GLP-1 analogue, exendin-4, promoted Akt phosphorylation and protein expression of cyclins A, D1 and E two- to threefold, in addition to cyclin D2. Pancreases from the vildagliptin-treated βIRKO mice exhibited increased cyclin D1 expression, while cyclin D2 expression was impaired. CONCLUSIONS/INTERPRETATION Activation of GLP-1 signalling compensates for impaired growth factor (insulin) signalling and enhances expression of cyclins to promote beta cell proliferation. Together, these data indicate the potential of GLP-1-related therapies to enhance beta cell proliferation and promote beneficial outcomes in models with dysfunctional beta cells.
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Affiliation(s)
- Dan Kawamori
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Room 410, One Joslin Place, Boston, MA, 02215, USA
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
- Medical Education Center, Faculty of Medicine, Osaka University, Osaka, Japan
| | - Jun Shirakawa
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Room 410, One Joslin Place, Boston, MA, 02215, USA
| | - Chong Wee Liew
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Room 410, One Joslin Place, Boston, MA, 02215, USA
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA
| | - Jiang Hu
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Room 410, One Joslin Place, Boston, MA, 02215, USA
| | - Tomoaki Morioka
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Room 410, One Joslin Place, Boston, MA, 02215, USA
- Department of Metabolism, Endocrinology and Molecular Medicine, Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Alokesh Duttaroy
- Cardiovascular & Metabolic Diseases, Novartis Institutes for Biomedical Research, Inc., Cambridge, MA, USA
| | | | - Rohit N Kulkarni
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Room 410, One Joslin Place, Boston, MA, 02215, USA.
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Boston, MA, USA.
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Sai W, Tian H, Yang K, Tang D, Bao J, Ge Y, Song X, Zhang Y, Luo C, Gao X, Yao W. Systematic Design of Trypsin Cleavage Site Mutated Exendin4-Cysteine 1, an Orally Bioavailable Glucagon-Like Peptide-1 Receptor Agonist. Int J Mol Sci 2017; 18:ijms18030578. [PMID: 28282854 PMCID: PMC5372594 DOI: 10.3390/ijms18030578] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/26/2017] [Accepted: 03/02/2017] [Indexed: 12/17/2022] Open
Abstract
Exendin-4 is a strong therapeutic candidate for the treatment of metabolic syndrome. Related receptor agonist drugs have been on the market since 2005. However, technical limitations and the pain caused by subcutaneous injection have severely limited patient compliance. The goal of the study is to investigate a biologically active exendin-4 analog could be administered orally. Using intraperitoneal glucose tolerance tests, we discovered that exendin4-cysteine administered by oral gavage had a distinct hypoglycemic effect in C57BL/6J mice. Using Rosetta Design and Amber, we designed and screened a series of exendin4-cysteine analogs to identify those that retained biological activity while resisting trypsin digestion. Trypsin Cleavage Site Mutated Exendin4-cysteine 1 (TSME-1), an analog whose bioactivity was similar to exendin-4 and was almost completely resistant to trypsin, was screened out. In addition, TSME-1 significantly normalized the blood glucose levels and the availability of TSME-1 was significantly higher than that of exendin-4 and exendin4-cysteine. Collectively orally administered TSME-1, a trypsin-resistant exendin-4 analog obtained by the system, is a strong candidate for future treatments of type 2 diabetes.
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Affiliation(s)
- Wenbo Sai
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Hong Tian
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Kangmin Yang
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Daoqi Tang
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Jinxiao Bao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Yang Ge
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Xiaoda Song
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Yu Zhang
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Cheng Luo
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Xiangdong Gao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
| | - Wenbing Yao
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, China.
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Roussel M, Mathieu J, Dalle S. Molecular mechanisms redirecting the GLP-1 receptor signalling profile in pancreatic β-cells during type 2 diabetes. Horm Mol Biol Clin Investig 2017; 26:87-95. [PMID: 26953712 DOI: 10.1515/hmbci-2015-0071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 01/24/2016] [Indexed: 02/06/2023]
Abstract
Treatments with β-cell preserving properties are essential for the management of type 2 diabetes (T2D), and the new therapeutic avenues, developed over the last years, rely on the physiological role of glucagon-like peptide-1 (GLP-1). Sustained pharmacological levels of GLP-1 are achieved by subcutaneous administration of GLP-1 analogues, while transient and lower physiological levels of GLP-1 are attained following treatment with inhibitors of dipeptidylpeptidase 4 (DPP4), an endoprotease which degrades the peptide. Both therapeutic classes display a sustained and durable hypoglycaemic action in patients with T2D. However, the GLP-1 incretin effect is known to be reduced in patients with T2D, and GLP-1 analogues and DPP4 inhibitors were shown to lose their effectiveness over time in some patients. The pathological mechanisms behind these observations can be either a decrease in GLP-1 secretion from intestinal L-cells and, as a consequence, a reduction in GLP-1 plasma concentrations, combined or not with a reduced action of GLP-1 in the β-cell, the so-called GLP-1 resistance. Much evidence for a GLP-1 resistance of the β-cell in subjects with T2D have emerged. Here, we review the potential roles of the genetic background, the hyperglycaemia, the hyperlipidaemia, the prostaglandin E receptor 3, the nuclear glucocorticoid receptor, the GLP-1R desensitization and internalisation processes, and the β-arrestin-1 expression levels on GLP-1 resistance in β-cells during T2D.
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36
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Modi H, Jacovetti C, Tarussio D, Metref S, Madsen OD, Zhang FP, Rantakari P, Poutanen M, Nef S, Gorman T, Regazzi R, Thorens B. Autocrine Action of IGF2 Regulates Adult β-Cell Mass and Function. Diabetes 2015; 64:4148-57. [PMID: 26384384 DOI: 10.2337/db14-1735] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 08/30/2015] [Indexed: 11/13/2022]
Abstract
Insulin-like growth factor 2 (IGF2), produced and secreted by adult β-cells, functions as an autocrine activator of the β-cell insulin-like growth factor 1 receptor signaling pathway. Whether this autocrine activity of IGF2 plays a physiological role in β-cell and whole-body physiology is not known. Here, we studied mice with β-cell-specific inactivation of Igf2 (βIGF2KO mice) and assessed β-cell mass and function in aging, pregnancy, and acute induction of insulin resistance. We showed that glucose-stimulated insulin secretion (GSIS) was markedly reduced in old female βIGF2KO mice; glucose tolerance was, however, normal because of increased insulin sensitivity. While on a high-fat diet, both male and female βIGF2KO mice displayed lower GSIS compared with control mice, but reduced β-cell mass was observed only in female βIGF2KO mice. During pregnancy, there was no increase in β-cell proliferation and mass in βIGF2KO mice. Finally, β-cell mass expansion in response to acute induction of insulin resistance was lower in βIGF2KO mice than in control mice. Thus, the autocrine action of IGF2 regulates adult β-cell mass and function to preserve in vivo GSIS in aging and to adapt β-cell mass in response to metabolic stress, pregnancy hormones, and acute induction of insulin resistance.
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Affiliation(s)
- Honey Modi
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Cecile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Salima Metref
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ole D Madsen
- Hagedorn Research, Diabetes Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Fu-Ping Zhang
- Department of Physiology and Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Pia Rantakari
- Department of Physiology and Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Matti Poutanen
- Department of Physiology and Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Serge Nef
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Tracy Gorman
- AstraZeneca, High-Content Biology, Discovery Sciences, Alderley Park, Macclesfield, Cheshire, U.K
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Stewart AF, Hussain MA, García-Ocaña A, Vasavada RC, Bhushan A, Bernal-Mizrachi E, Kulkarni RN. Human β-cell proliferation and intracellular signaling: part 3. Diabetes 2015; 64:1872-85. [PMID: 25999530 PMCID: PMC4439562 DOI: 10.2337/db14-1843] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This is the third in a series of Perspectives on intracellular signaling pathways coupled to proliferation in pancreatic β-cells. We contrast the large knowledge base in rodent β-cells with the more limited human database. With the increasing incidence of type 1 diabetes and the recognition that type 2 diabetes is also due in part to a deficiency of functioning β-cells, there is great urgency to identify therapeutic approaches to expand human β-cell numbers. Therapeutic approaches might include stem cell differentiation, transdifferentiation, or expansion of cadaver islets or residual endogenous β-cells. In these Perspectives, we focus on β-cell proliferation. Past Perspectives reviewed fundamental cell cycle regulation and its upstream regulation by insulin/IGF signaling via phosphatidylinositol-3 kinase/mammalian target of rapamycin signaling, glucose, glycogen synthase kinase-3 and liver kinase B1, protein kinase Cζ, calcium-calcineurin-nuclear factor of activated T cells, epidermal growth factor/platelet-derived growth factor family members, Wnt/β-catenin, leptin, and estrogen and progesterone. Here, we emphasize Janus kinase/signal transducers and activators of transcription, Ras/Raf/extracellular signal-related kinase, cadherins and integrins, G-protein-coupled receptors, and transforming growth factor β signaling. We hope these three Perspectives will serve to introduce these pathways to new researchers and will encourage additional investigators to focus on understanding how to harness key intracellular signaling pathways for therapeutic human β-cell regeneration for diabetes.
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Affiliation(s)
- Andrew F Stewart
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mehboob A Hussain
- Departments of Medicine and Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD
| | - Adolfo García-Ocaña
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Rupangi C Vasavada
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Anil Bhushan
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | - Ernesto Bernal-Mizrachi
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI, and VA Ann Arbor Healthcare System, Ann Arbor, MI
| | - Rohit N Kulkarni
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, MA
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38
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Jacovetti C, Jimenez V, Ayuso E, Laybutt R, Peyot ML, Prentki M, Bosch F, Regazzi R. Contribution of Intronic miR-338-3p and Its Hosting Gene AATK to Compensatory β-Cell Mass Expansion. Mol Endocrinol 2015; 29:693-702. [PMID: 25751313 DOI: 10.1210/me.2014-1299] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The elucidation of the mechanisms directing β-cell mass regeneration and maintenance is of interest, because the deficit of β-cell mass contributes to diabetes onset and progression. We previously found that the level of the microRNA (miRNA) miR-338-3p is decreased in pancreatic islets from rodent models displaying insulin resistance and compensatory β-cell mass expansion, including pregnant rats, diet-induced obese mice, and db/db mice. Transfection of rat islet cells with oligonucleotides that specifically block miR-338-3p activity increased the fraction of proliferating β-cells in vitro and promoted survival under proapoptotic conditions without affecting the capacity of β-cells to release insulin in response to glucose. Here, we evaluated the role of miR-338-3p in vivo by injecting mice with an adeno-associated viral vector permitting specific sequestration of this miRNA in β-cells. We found that the adeno-associated viral construct increased the fraction of proliferating β-cells confirming the data obtained in vitro. miR-338-3p is generated from an intron of the gene coding for apoptosis-associated tyrosine kinase (AATK). Similarly to miR-338-3p, we found that AATK is down-regulated in rat and human islets and INS832/13 β-cells in the presence of the cAMP-raising agents exendin-4, estradiol, and a G-protein-coupled Receptor 30 agonist. Moreover, AATK expression is reduced in islets of insulin resistant animal models and selective silencing of AATK in INS832/13 cells by RNA interference promoted β-cell proliferation. The results point to a coordinated reduction of miR-338-3p and AATK under insulin resistance conditions and provide evidence for a cooperative action of the miRNA and its hosting gene in compensatory β-cell mass expansion.
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Affiliation(s)
- Cécile Jacovetti
- Department of Fundamental Neurosciences (C.J., R.R.), University of Lausanne, 1005 Lausanne, Switzerland; Center of Animal Biotechnology and Gene Therapy and Department of Biochemistry and Molecular Biology (V.J., E.A., F.B.), School of Veterinary Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain; Diabetes and Obesity Research Program (R.L.), Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, 2010 New South Wales, Australia; and Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier de l'Université de Montréal (M.-L.P., M.P.), and Departments of Nutrition, Biochemistry and Molecular Medicine, University of Montreal, Quebec, H2X 0A9 Canada
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Lee KL, Middleditch MJ, Williams GM, Brimble MA, Cooper GJS. Using mass spectrometry to detect, differentiate, and semiquantitate closely related peptide hormones in complex milieu: measurement of IGF-II and vesiculin. Endocrinology 2015; 156:1194-9. [PMID: 25545381 DOI: 10.1210/en.2014-1593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The search for an islet β-cell growth factor has been a key objective in recent diabetes research, because the ability to regenerate and/or protect the functioning β-cell population in patients could result in a great advancement for diabetes treatment. IGF-I and IGF-II are known to play crucial roles in fetal growth and prenatal development, and there is growing evidence that IGF-II increases β-cell proliferation and survival in vitro and in vivo. A search for the source of IGF-II-like immunoreactivity in isolated β-cell secretory granules from the murine cell line βTC6-F7 revealed a novel 2-chain IGF-II-derived peptide, which we named vesiculin and which has been shown to be a full insulin agonist. Here, we present a liquid chromatography-tandem mass spectrometry method that enables selective detection and semiquantitation of the highly related IGF-II and vesiculin molecules. We have used this method to measure these 2 peptides in conditioned media from 2 β-cell lines, produced under increasing glucose concentrations. This technique detected both IGF-II and vesiculin in media conditioned by MIN6 and βTC6-F7 cells at levels in the range of 0 to 6 μM (total insulin, 80-450 μM) and revealed a glucose-stimulated increase in insulin, IGF-II, and vesiculin. IGF-II was detected in adult human and neonatal mouse serum in high levels, but vesiculin was not present. The methodology we present herein has utility for detecting and differentiating active peptides that are highly related and of low abundance.
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Affiliation(s)
- Kate L Lee
- School of Biological Sciences (K.L.L., M.J.M., G.J.S.C.), School of Chemical Sciences (G.M.W., M.A.B.), and Maurice Wilkins Centre for Molecular BioDiscovery (M.J.M., M.A.B., G.J.S.C.), The University of Auckland, Auckland 1010, New Zealand; and Centre for Advanced Discovery and Experimental Therapeutics (G.J.S.C.), Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, and the School of Biomedicine, the Medical School, University of Manchester, Manchester M13 9WL, United Kingdom
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Patel D, Ythier D, Brozzi F, Eizirik DL, Thorens B. Clic4, a novel protein that sensitizes β-cells to apoptosis. Mol Metab 2015; 4:253-64. [PMID: 25830089 PMCID: PMC4354924 DOI: 10.1016/j.molmet.2015.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 01/06/2015] [Accepted: 01/09/2015] [Indexed: 01/09/2023] Open
Abstract
Objectives Chloride intracellular channel protein 4 (Clic4) is a ubiquitously expressed protein involved in multiple cellular processes including cell-cycle control, cell differentiation, and apoptosis. Here, we investigated the role of Clic4 in pancreatic β-cell apoptosis. Methods We used βTC-tet cells and islets from β-cell specific Clic4 knockout mice (βClic4KO) and assessed cytokine-induced apoptosis, Bcl2 family protein expression and stability, and identified Clic4-interacting proteins by co-immunoprecipitation and mass spectrometry analysis. Results We show that cytokines increased Clic4 expression in βTC-tet cells and in mouse islets and siRNA-mediated silencing of Clic4 expression in βTC-tet cells or its genetic inactivation in islets β-cells, reduced cytokine-induced apoptosis. This was associated with increased expression of Bcl-2 and increased expression and phosphorylation of Bad. Measurement of Bcl-2 and Bad half-lives in βTC-tet cells showed that Clic4 silencing increased the stability of these proteins. In primary islets β-cells, absence of Clic4 expression increased Bcl-2 and Bcl-xL expression as well as expression and phosphorylation of Bad. Mass-spectrometry analysis of proteins co-immunoprecipitated with Clic4 from βTC-tet cells showed no association of Clic4 with Bcl-2 family proteins. However, Clic4 co-purified with proteins from the proteasome suggesting a possible role for Clic4 in regulating protein degradation. Conclusions Collectively, our data show that Clic4 is a cytokine-induced gene that sensitizes β-cells to apoptosis by reducing the steady state levels of Bcl-2, Bad and phosphorylated Bad.
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Affiliation(s)
- Dhaval Patel
- Center for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland
| | - Damien Ythier
- Center for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland
| | - Flora Brozzi
- ULB Center for Diabetes Research, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Genopode Building, CH-1015 Lausanne, Switzerland
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Hwang JY, Sim X, Wu Y, Liang J, Tabara Y, Hu C, Hara K, Tam CHT, Cai Q, Zhao Q, Jee S, Takeuchi F, Go MJ, Ong RTH, Ohkubo T, Kim YJ, Zhang R, Yamauchi T, So WY, Long J, Gu D, Lee NR, Kim S, Katsuya T, Oh JH, Liu J, Umemura S, Kim YJ, Jiang F, Maeda S, Chan JCN, Lu W, Hixson JE, Adair LS, Jung KJ, Nabika T, Bae JB, Lee MH, Seielstad M, Young TL, Teo YY, Kita Y, Takashima N, Osawa H, Lee SH, Shin MH, Shin DH, Choi BY, Shi J, Gao YT, Xiang YB, Zheng W, Kato N, Yoon M, He J, Shu XO, Ma RCW, Kadowaki T, Jia W, Miki T, Qi L, Tai ES, Mohlke KL, Han BG, Cho YS, Kim BJ. Genome-wide association meta-analysis identifies novel variants associated with fasting plasma glucose in East Asians. Diabetes 2015; 64:291-8. [PMID: 25187374 PMCID: PMC4274808 DOI: 10.2337/db14-0563] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fasting plasma glucose (FPG) has been recognized as an important indicator for the overall glycemic state preceding the onset of metabolic diseases. So far, most indentified genome-wide association loci for FPG were derived from populations with European ancestry, with a few exceptions. To extend a thorough catalog for FPG loci, we conducted meta-analyses of 13 genome-wide association studies in up to 24,740 nondiabetic subjects with East Asian ancestry. Follow-up replication analyses in up to an additional 21,345 participants identified three new FPG loci reaching genome-wide significance in or near PDK1-RAPGEF4, KANK1, and IGF1R. Our results could provide additional insight into the genetic variation implicated in fasting glucose regulation.
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Affiliation(s)
- Joo-Yeon Hwang
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Xueling Sim
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI Centre for Molecular Epidemiology, National University of Singapore, Singapore, Singapore
| | - Ying Wu
- Department of Genetics, University of North Carolina, Chapel Hill, NC
| | - Jun Liang
- Department of Nutrition, Harvard School of Public Health, Boston, MA
| | - Yasuharu Tabara
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Cheng Hu
- Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Kazuo Hara
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan Department of Integrated Molecular Science on Metabolic Diseases, 22nd Century Medical and Research Center, The University of Tokyo, Tokyo, Japan
| | - Claudia H T Tam
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong
| | - Qiuyin Cai
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center; and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Qi Zhao
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA
| | - Sunha Jee
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea
| | - Fumihiko Takeuchi
- Department of Gene Diagnostics and Therapeutics, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Min Jin Go
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Rick Twee Hee Ong
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Takayoshi Ohkubo
- Department of Planning for Drug Development and Clinical Evaluation, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Japan Department of Health Science, Shiga University of Medical Science, Shiga, Japan
| | - Young Jin Kim
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Rong Zhang
- Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Toshimasa Yamauchi
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Wing Yee So
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong
| | - Jirong Long
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center; and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Dongfeng Gu
- State Key Laboratory of Cardiovascular Disease, Department of Epidemiology, National Center for Cardiovascular Diseases, Beijing, China Population Genetics, Fuwai Hospital, National Center of Cardiovascular Diseases, Chinese Academy of Medical Sciences, Beijing, China Peking Union Medical College, Beijing, China
| | - Nanette R Lee
- Office of Population Studies Foundation, University of San Carlos, Cebu City, Philippines
| | - Soriul Kim
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea
| | - Tomohiro Katsuya
- Department of Clinical Gene Therapy, Osaka University Graduate School of Medicine, Suita, Japan
| | - Ji Hee Oh
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Jianjun Liu
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Satoshi Umemura
- Department of Medical Science and Cardiorenal Medicine, Yokohama City University School of Medicine, Yokohama, Japan
| | - Yeon-Jung Kim
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Feng Jiang
- Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Shiro Maeda
- Laboratory for Endocrinology, Metabolism and Kidney Diseases, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Juliana C N Chan
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong
| | - Wei Lu
- Shanghai Municipal Center for Disease Control & Prevention, Shanghai, China
| | - James E Hixson
- Human Genetics Center, The University of Texas School of Public Health, Houston, TX
| | - Linda S Adair
- Department of Nutrition, University of North Carolina, Chapel Hill, NC
| | - Keum Ji Jung
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea
| | - Toru Nabika
- Department of Functional Pathology, Shimane University School of Medicine, Izumo, Japan
| | - Jae-Bum Bae
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Mi Hee Lee
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Mark Seielstad
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA
| | - Terri L Young
- Center for Human Genetics, Duke University Medical Center, Durham, NC
| | - Yik Ying Teo
- Centre for Molecular Epidemiology, National University of Singapore, Singapore, Singapore Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore Department of Statistics and Applied Probability, National University of Singapore, Singapore, Singapore Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Yoshikuni Kita
- Department of Health Science, Shiga University of Medical Science, Shiga, Japan
| | - Naoyuki Takashima
- Department of Health Science, Shiga University of Medical Science, Shiga, Japan
| | - Haruhiko Osawa
- Department of Molecular and Genetic Medicine, Ehime University Graduate School of Medicine, Toon, Japan
| | - So-Hyun Lee
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Min-Ho Shin
- Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, South Korea
| | - Dong Hoon Shin
- Department of Occupational and Environmental Medicine, Keimyung University Dongsan Medical Center, Daegu, South Korea
| | - Bo Youl Choi
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, Korea
| | - Jiajun Shi
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center; and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Yu-Tang Gao
- Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yong-Bing Xiang
- Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei Zheng
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center; and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Norihiro Kato
- Department of Gene Diagnostics and Therapeutics, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Miwuk Yoon
- Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, Korea
| | - Jiang He
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA
| | - Xiao Ou Shu
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center; and Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Ronald C W Ma
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong
| | - Takashi Kadowaki
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Weiping Jia
- Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Tetsuro Miki
- Department of Geriatric Medicine, Ehime University Graduate School of Medicine, Toon, Japan
| | - Lu Qi
- Department of Nutrition, Harvard School of Public Health, Boston, MA
| | - E Shyong Tai
- Department of Gene Diagnostics and Therapeutics, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan Department of Medicine, National University of Singapore, Singapore, Singapore Duke-National University of Singapore Graduate Medical School, Singapore, Singapore
| | - Karen L Mohlke
- Department of Genetics, University of North Carolina, Chapel Hill, NC
| | - Bok-Ghee Han
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
| | - Yoon Shin Cho
- Department of Biomedical Science, Hallym University, Chuncheon, Korea
| | - Bong-Jo Kim
- Center for Genome Science, National Institute of Health, Osong Health Technology Administration Complex, Chungcheongbuk-do, Republic of Korea
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Papaetis GS. Incretin-based therapies in prediabetes: Current evidence and future perspectives. World J Diabetes 2014; 5:817-834. [PMID: 25512784 PMCID: PMC4265868 DOI: 10.4239/wjd.v5.i6.817] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Revised: 09/10/2014] [Accepted: 11/10/2014] [Indexed: 02/05/2023] Open
Abstract
The prevalence of type 2 diabetes (T2D) is evolving globally at an alarming rate. Prediabetes is an intermediate state of glucose metabolism that exists between normal glucose tolerance (NGT) and the clinical entity of T2D. Relentless β-cell decline and failure is responsible for the progression from NGT to prediabetes and eventually T2D. The huge burden resulting from the complications of T2D created the need of therapeutic strategies in an effort to prevent or delay its development. The beneficial effects of incretin-based therapies, dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists, on β-cell function in patients with T2D, together with their strictly glucose-depended mechanism of action, suggested their possible use in individuals with prediabetes when greater β-cell mass and function are preserved and the possibility of β-cell salvage is higher. The present paper summarizes the main molecular intracellular mechanisms through which GLP-1 exerts its activity on β-cells. It also explores the current evidence of incretin based therapies when administered in a prediabetic state, both in animal models and in humans. Finally it discusses the safety of incretin-based therapies as well as their possible role in order to delay or prevent T2D.
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Pabreja K, Mohd MA, Koole C, Wootten D, Furness SGB. Molecular mechanisms underlying physiological and receptor pleiotropic effects mediated by GLP-1R activation. Br J Pharmacol 2014; 171:1114-28. [PMID: 23889512 DOI: 10.1111/bph.12313] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/10/2013] [Accepted: 07/19/2013] [Indexed: 12/22/2022] Open
Abstract
The incidence of type 2 diabetes in developed countries is increasing yearly with a significant negative impact on patient quality of life and an enormous burden on the healthcare system. Current biguanide and thiazolidinedione treatments for type 2 diabetes have a number of clinical limitations, the most serious long-term limitation being the eventual need for insulin replacement therapy (Table 1). Since 2007, drugs targeting the glucagon-like peptide-1 (GLP-1) receptor have been marketed for the treatment of type 2 diabetes. These drugs have enjoyed a great deal of success even though our underlying understanding of the mechanisms for their pleiotropic effects remain poorly characterized even while major pharmaceutical companies actively pursue small molecule alternatives. Coupling of the GLP-1 receptor to more than one signalling pathway (pleiotropic signalling) can result in ligand-dependent signalling bias and for a peptide receptor such as the GLP-1 receptor this can be exaggerated with the use of small molecule agonists. Better consideration of receptor signalling pleiotropy will be necessary for future drug development. This is particularly important given the recent failure of taspoglutide, the report of increased risk of pancreatitis associated with GLP-1 mimetics and the observed clinical differences between liraglutide, exenatide and the newly developed long-acting exenatide long acting release, albiglutide and dulaglutide.
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Affiliation(s)
- K Pabreja
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic., Australia
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Saraiva FK, Sposito AC. Cardiovascular effects of glucagon-like peptide 1 (GLP-1) receptor agonists. Cardiovasc Diabetol 2014; 13:142. [PMID: 25338737 PMCID: PMC4216654 DOI: 10.1186/s12933-014-0142-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/06/2014] [Indexed: 02/08/2023] Open
Abstract
Patients with type 2 diabetes have a several-fold increased risk of developing cardiovascular disease when compared with nondiabetic controls. Myocardial infarction and stroke are responsible for 75% of all death in patients with diabetes, who present a 2-4× increased incidence of death from coronary artery disease. Patients with diabetes are considered for cardiovascular disease secondary prevention because their risk level is similar to that reported in patients without diabetes who have already suffered a myocardial infarction. More recently, with a better risk factors control, mainly in intensive LDL cholesterol targets with statins, a significant decrease in acute cardiovascular events was observed in population with diabetes. Together with other major risk factors, type 2 diabetes must be considered as an important cause of cardiovascular disease.Glucagon like peptide-1 receptor agonists represent a novel class of anti-hyperglycemic agents that have a cardiac-friendly profile, preserve neuronal cells and inhibit neuronal degeneration, an anti-inflammatory effect in liver protecting it against steatosis, increase insulin sensitivity, promote weight loss, and increase satiety or anorexia.This review is intended to rationally compile the multifactorial cardiovascular effects of glucagon-like peptide-1 receptor agonists available for the treatment of patients with type 2 diabetes.
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Affiliation(s)
| | - Andrei C Sposito
- Laboratory of Atherosclerosis and Vascular Biology (AteroLab), Cardiology Division, State University of Campinas Medicine School (Unicamp), Campinas, Sao Paulo, 13084-971, Brazil.
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Modi H, Cornu M, Thorens B. Glutamine stimulates biosynthesis and secretion of insulin-like growth factor 2 (IGF2), an autocrine regulator of beta cell mass and function. J Biol Chem 2014; 289:31972-31982. [PMID: 25271169 DOI: 10.1074/jbc.m114.587733] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IGF2 is an autocrine ligand for the beta cell IGF1R receptor and GLP-1 increases the activity of this autocrine loop by enhancing IGF1R expression, a mechanism that mediates the trophic effects of GLP-1 on beta cell mass and function. Here, we investigated the regulation of IGF2 biosynthesis and secretion. We showed that glutamine rapidly and strongly induced IGF2 mRNA translation using reporter constructs transduced in MIN6 cells and primary islet cells. This was followed by rapid secretion of IGF2 via the regulated pathway, as revealed by the presence of mature IGF2 in insulin granule fractions and by inhibition of secretion by nimodipine and diazoxide. When maximally stimulated by glutamine, the amount of secreted IGF2 rapidly exceeded its initial intracellular pool and tolbutamide, and high K(+) increased IGF2 secretion only marginally. This indicates that the intracellular pool of IGF2 is small and that sustained secretion requires de novo synthesis. The stimulatory effect of glutamine necessitates its metabolism but not mTOR activation. Finally, exposure of insulinomas or beta cells to glutamine induced Akt phosphorylation, an effect that was dependent on IGF2 secretion, and reduced cytokine-induced apoptosis. Thus, glutamine controls the activity of the beta cell IGF2/IGF1R autocrine loop by increasing the biosynthesis and secretion of IGF2. This autocrine loop can thus integrate changes in feeding and metabolic state to adapt beta cell mass and function.
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Affiliation(s)
- Honey Modi
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Marion Cornu
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland.
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46
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Xie J, El Sayed NM, Qi C, Zhao X, Moore CE, Herbert TP. Exendin-4 stimulates islet cell replication via the IGF1 receptor activation of mTORC1/S6K1. J Mol Endocrinol 2014; 53:105-15. [PMID: 24994913 DOI: 10.1530/jme-13-0200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glucagon-like peptide 1 receptor (GLP1R) agonists, such as exendin-4, potentiate glucose-stimulated insulin secretion and are currently used in the management of type 2 diabetes. Interestingly, GLP1R agonists also have the ability to augment β-cell mass. In this report, we provide evidence that in the presence of glucose, exendin-4 stimulates rodent islet cell DNA replication via the activation of ribosomal protein S6 kinase 1 (S6K1) and that this is mediated by the protein kinase B (PKB)-dependent activation of mTOR complex 1 (mTORC1). We show that activation of this pathway is caused by the autocrine or paracrine activation of the IGF1 receptor (IGF1R), as siRNA-mediated knockdown of the IGF1R effectively blocked exendin-4-stimulated PKB and mTORC1 activation. In contrast, pharmacological inactivation of the epidermal growth factor receptor has no discernible effect on exendin-4-stimulated PKB or mTORC1 activation. Therefore, we conclude that GLP1R agonists stimulate β-cell proliferation via the PKB-dependent stimulation of mTORC1/S6K1 whose activation is mediated through the autocrine/paracrine activation of the IGF1R. This work provides a better understanding of the molecular basis of GLP1 agonist-induced β-cell proliferation which could potentially be exploited in the identification of novel drug targets that increase β-cell mass.
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Affiliation(s)
- Jianling Xie
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Norhan M El Sayed
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Cheng Qi
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Xuechan Zhao
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Claire E Moore
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
| | - Terence P Herbert
- Department of Cell Physiology and PharmacologyUniversity of Leicester, Henry Wellcome Building, University Road, Leicester LE1 9HN, UK
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Vallois D, Niederhäuser G, Ibberson M, Nagaray V, Marselli L, Marchetti P, Chatton JY, Thorens B. Gluco-incretins regulate beta-cell glucose competence by epigenetic silencing of Fxyd3 expression. PLoS One 2014; 9:e103277. [PMID: 25058609 PMCID: PMC4110016 DOI: 10.1371/journal.pone.0103277] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 06/28/2014] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND/AIMS Gluco-incretin hormones increase the glucose competence of pancreatic beta-cells by incompletely characterized mechanisms. METHODS We searched for genes that were differentially expressed in islets from control and Glp1r-/-; Gipr-/- (dKO) mice, which show reduced glucose competence. Overexpression and knockdown studies; insulin secretion analysis; analysis of gene expression in islets from control and diabetic mice and humans as well as gene methylation and transcriptional analysis were performed. RESULTS Fxyd3 was the most up-regulated gene in glucose incompetent islets from dKO mice. When overexpressed in beta-cells Fxyd3 reduced glucose-induced insulin secretion by acting downstream of plasma membrane depolarization and Ca++ influx. Fxyd3 expression was not acutely regulated by cAMP raising agents in either control or dKO adult islets. Instead, expression of Fxyd3 was controlled by methylation of CpGs present in its proximal promoter region. Increased promoter methylation reduced Fxyd3 transcription as assessed by lower abundance of H3K4me3 at the transcriptional start site and in transcription reporter assays. This epigenetic imprinting was initiated perinatally and fully established in adult islets. Glucose incompetent islets from diabetic mice and humans showed increased expression of Fxyd3 and reduced promoter methylation. CONCLUSIONS/INTERPRETATION Because gluco-incretin secretion depends on feeding the epigenetic regulation of Fxyd3 expression may link nutrition in early life to establishment of adult beta-cell glucose competence; this epigenetic control is, however, lost in diabetes possibly as a result of gluco-incretin resistance and/or de-differentiation of beta-cells that are associated with the development of type 2 diabetes.
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Affiliation(s)
- David Vallois
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Guy Niederhäuser
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Mark Ibberson
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
- Vital-IT group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Lorella Marselli
- Department of Endocrinology and Metabolism, Ospedale di Cisanello, Pisa, Italy
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, Ospedale di Cisanello, Pisa, Italy
| | - Jean-Yves Chatton
- Department of Cell Biology and Morphology, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Role of soluble adenylyl cyclase in cell death and growth. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2646-55. [PMID: 25010002 DOI: 10.1016/j.bbadis.2014.06.034] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 12/13/2022]
Abstract
cAMP signaling is an evolutionarily conserved intracellular communication system controlling numerous cellular functions. Until recently, transmembrane adenylyl cyclase (tmAC) was considered the major source for cAMP in the cell, and the role of cAMP signaling was therefore attributed exclusively to the activity of this family of enzymes. However, increasing evidence demonstrates the role of an alternative, intracellular source of cAMP produced by type 10 soluble adenylyl cyclase (sAC). In contrast to tmAC, sAC produces cAMP in various intracellular microdomains close to specific cAMP targets, e.g., in nucleus and mitochondria. Ongoing research demonstrates involvement of sAC in diverse physiological and pathological processes. The present review is focused on the role of cAMP signaling, particularly that of sAC, in cell death and growth. Although the contributions of sAC to the regulation of these cellular functions have only recently been discovered, current data suggest that sAC plays key roles in mitochondrial bioenergetics and the mitochondrial apoptosis pathway, as well as cell proliferation and development. Furthermore, recent reports suggest the importance of sAC in several pathologies associated with apoptosis as well as in oncogenesis. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Holz GG, Leech CA, Chepurny OG. New insights concerning the molecular basis for defective glucoregulation in soluble adenylyl cyclase knockout mice. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2593-600. [PMID: 24980705 DOI: 10.1016/j.bbadis.2014.06.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 01/09/2023]
Abstract
Recently published findings indicate that a knockout (KO) of soluble adenylyl cyclase (sAC, also known as AC-10) gene expression in mice leads to defective glucoregulation that is characterized by reduced pancreatic insulin secretion and reduced intraperitoneal glucose tolerance. Summarized here are current concepts regarding the molecular basis for this phenotype, with special emphasis on the potential role of sAC as a determinant of glucose-stimulated insulin secretion. Highlighted is new evidence that in pancreatic beta cells, oxidative glucose metabolism stimulates mitochondrial CO₂production that in turn generates bicarbonate ion (HCO(3)(-)). Since HCO(3)(-) binds to and directly stimulates the activity of sAC, we propose that glucose-stimulated cAMP production in beta cells is mediated not simply by transmembrane adenylyl cyclases (TMACs), but also by sAC. Based on evidence that sAC is expressed in mitochondria, there exists the possibility that beta-cell glucose metabolism is linked to mitochondrial cAMP production with consequent facilitation of oxidative phosphorylation. Since sAC is also expressed in the cytoplasm, sAC catalyzed cAMP production may activate cAMP sensors such as PKA and Epac2 to control ion channel function, intracellular Ca²⁺ handling, and Ca²⁺-dependent exocytosis. Thus, we propose that the existence of sAC in beta cells provides a new and unexpected explanation for previously reported actions of glucose metabolism to stimulate cAMP production. It seems possible that alterations of sAC activity might be of importance when evaluating new strategies for the treatment of type 2 diabetes (T2DM), or when evaluating why glucose metabolism fails to stimulate insulin secretion in patients diagnosed with T2DM. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.
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Affiliation(s)
- George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA.
| | - Colin A Leech
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY 13210, USA
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Lee YS, Jun HS. Anti-diabetic actions of glucagon-like peptide-1 on pancreatic beta-cells. Metabolism 2014; 63:9-19. [PMID: 24140094 DOI: 10.1016/j.metabol.2013.09.010] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 09/05/2013] [Accepted: 09/14/2013] [Indexed: 12/11/2022]
Abstract
Glucagon-like peptide-1 (GLP-1), an incretin hormone, is released from intestinal L-cells in response to nutrients. GLP-1 lowers blood glucose levels by stimulating insulin secretion from pancreatic beta-cells in a glucose-dependent manner. In addition, GLP-1 slows gastric emptying, suppresses appetite, reduces plasma glucagon, and stimulates glucose disposal, which are beneficial for glucose homeostasis. Therefore, incretin-based therapies such as GLP-1 receptor agonists and inhibitors of dipeptidyl peptidase IV, an enzyme which inactivates GLP-1, have been developed for treatment of diabetes. This review outlines our knowledge of the actions of GLP-1 on insulin secretion and biosynthesis, beta-cell proliferation and regeneration, and protection against beta-cell damage, as well as the involvement of recently discovered signaling pathways of GLP-1 action, mainly focusing on pancreatic beta-cells.
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Affiliation(s)
- Young-Sun Lee
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University, 7-45 Songdo-dong, Yeonsu-ku, Incheon 406-840, South Korea
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