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Perez-Frances M, Bru-Tari E, Cohrs C, Abate MV, van Gurp L, Furuyama K, Speier S, Thorel F, Herrera PL. Regulated and adaptive in vivo insulin secretion from islets only containing β-cells. Nat Metab 2024:10.1038/s42255-024-01114-8. [PMID: 39169271 DOI: 10.1038/s42255-024-01114-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/22/2024] [Indexed: 08/23/2024]
Abstract
Insulin-producing β-cells in pancreatic islets are regulated by systemic cues and, locally, by adjacent islet hormone-producing 'non-β-cells' (namely α-cells, δ-cells and γ-cells). Yet whether the non-β-cells are required for accurate insulin secretion is unclear. Here, we studied mice in which adult islets are exclusively composed of β-cells and human pseudoislets containing only primary β-cells. Mice lacking non-β-cells had optimal blood glucose regulation, enhanced glucose tolerance, insulin sensitivity and restricted body weight gain under a high-fat diet. The insulin secretion dynamics in islets composed of only β-cells was comparable to that in intact islets. Similarly, human β-cell pseudoislets retained the glucose-regulated mitochondrial respiration, insulin secretion and exendin-4 responses of entire islets. The findings indicate that non-β-cells are dispensable for blood glucose homeostasis and β-cell function. These results support efforts aimed at developing diabetes treatments by generating β-like clusters devoid of non-β-cells, such as from pluripotent stem cells differentiated in vitro or by reprograming non-β-cells into insulin producers in situ.
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Affiliation(s)
- Marta Perez-Frances
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Eva Bru-Tari
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Christian Cohrs
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Clinic Carl Gustav Carus of Technische Universität Dresden, Helmholtz Zentrum München, Neuherberg, Germany
| | - Maria Valentina Abate
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Léon van Gurp
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Kenichiro Furuyama
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Stephan Speier
- Institute of Physiology, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Zentrum München at the University Clinic Carl Gustav Carus of Technische Universität Dresden, Helmholtz Zentrum München, Neuherberg, Germany
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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2
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Kusminski CM, Perez-Tilve D, Müller TD, DiMarchi RD, Tschöp MH, Scherer PE. Transforming obesity: The advancement of multi-receptor drugs. Cell 2024; 187:3829-3853. [PMID: 39059360 PMCID: PMC11286204 DOI: 10.1016/j.cell.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 07/28/2024]
Abstract
For more than a century, physicians have searched for ways to pharmacologically reduce excess body fat. The tide has finally turned with recent advances in biochemically engineered agonists for the receptor of glucagon-like peptide-1 (GLP-1) and their use in GLP-1-based polyagonists. These polyagonists reduce body weight through complementary pharmacology by incorporating the receptors for glucagon and/or the glucose-dependent insulinotropic polypeptide (GIP). In their most advanced forms, gut-hormone polyagonists achieve an unprecedented weight reduction of up to ∼20%-30%, offering a pharmacological alternative to bariatric surgery. Along with favorable effects on glycemia, fatty liver, and kidney disease, they also offer beneficial effects on the cardiovascular system and adipose tissue. These new interventions, therefore, hold great promise for the future of anti-obesity medications.
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Affiliation(s)
- Christine M Kusminski
- Touchstone Diabetes Center, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Diego Perez-Tilve
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Munich, Munich, Germany; German Center for Diabetes Research (DZD) and Walther-Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
| | | | - Matthias H Tschöp
- Helmholtz Munich, Munich, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität, Munich, Germany
| | - Philipp E Scherer
- Touchstone Diabetes Center, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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3
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Pixner T, Chaikouskaya T, Lauth W, Zimmermann G, Mörwald K, Lischka J, Furthner D, Awender E, Geiersberger S, Maruszczak K, Forslund A, Anderwald CH, Cadamuro J, Weghuber D, Bergsten P. Rise in fasting and dynamic glucagon levels in children and adolescents with obesity is moderate in subjects with impaired fasting glucose but accentuated in subjects with impaired glucose tolerance or type 2 diabetes. Front Endocrinol (Lausanne) 2024; 15:1368570. [PMID: 39027470 PMCID: PMC11254805 DOI: 10.3389/fendo.2024.1368570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 06/14/2024] [Indexed: 07/20/2024] Open
Abstract
Background Fasting levels of glucagon are known to be elevated in youth and adults with type 2 diabetes mellitus (T2D). Children and adolescents with obesity were previously reported to show increasing fasting and post-glucose-challenge hyperglucagonemia across the spectrum of glucose tolerance, while no data are available in those with impaired fasting glucose (IFG). Materials and methods Individuals from the Beta-JUDO study population (Uppsala and Salzburg 2010-2016) (n=101, age 13.3 ± 2.8, m/f =50/51) were included (90 with overweight or obesity, 11 with normal weight). Standardized OGTT were performed and plasma glucose, glucagon and insulin concentrations assessed at baseline, 5, 10, 15, 30, 60, 90 and 120 minutes. Patients were grouped according to their glycemic state in six groups with normal glucose metabolism (NGM) and normal weight (NG-NW), NGM with obesity or overweight (NG-O), impaired glucose tolerance (IGT), impaired fasting glucose (IFG), IGT+IFG and T2D, and in two groups with NGM and impaired glucose metabolism (IGM), for statistical analysis. Results and conclusion Glucagon concentrations were elevated in young normoglycemic individuals with overweight or obesity (NG-O) compared to normoglycemic individuals with normal weight. Glucagon levels, fasting and dynamic, increased with progressing glycemic deterioration, except in IFG, where levels were comparable to those in NG-O. All glycemic groups showed an overall suppression of glucagon during OGTT. An initial increase of glucagon could be observed in T2D. In T2D, glucagon showed a strong direct linear correlation with plasma glucose levels during OGTT. Glucagon in adolescents, as in adults, may play a role in the disease progression of T2D.
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Affiliation(s)
- Thomas Pixner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Tatsiana Chaikouskaya
- Institut national supérieur des sciences agronomiques de l'alimentation et de l'environnement, Dijon, France
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Wanda Lauth
- Biostatistics and Big Medical Data, Lab for Intelligent Data Analytics (IDA) Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Georg Zimmermann
- Biostatistics and Big Medical Data, Lab for Intelligent Data Analytics (IDA) Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Katharina Mörwald
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Julia Lischka
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Dieter Furthner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Elisabeth Awender
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Sabine Geiersberger
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Clinical Research Center Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Katharina Maruszczak
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Anders Forslund
- Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Christian-Heinz Anderwald
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
- Direction, Arnoldstein Healthcare Centre, Arnoldstein, Austria
| | - Janne Cadamuro
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Daniel Weghuber
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Peter Bergsten
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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4
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Hayashi Y. Advances in basic research on glucagon and alpha cells. Diabetol Int 2024; 15:348-352. [PMID: 39101161 PMCID: PMC11291817 DOI: 10.1007/s13340-024-00696-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 01/17/2024] [Indexed: 08/06/2024]
Abstract
The regulation of plasma amino acid levels by glucagon in humans first attracted the attention of researchers in the 1980s. Recent basic research using animal models of glucagon deficiency suggested that a major physiological role of glucagon is the regulation of amino acid metabolism rather than to increase blood glucose levels. In this regard, novel feedback regulatory mechanisms that are mediated by glucagon and amino acids have recently been described between islet alpha cells and the liver. Increasingly, hyperglucagonemia in humans with diabetes and/or nonalcoholic fatty liver diseases is reported to likely be a compensatory response to hepatic glucagon resistance. Severe glucagon resistance due to a glucagon receptor mutation in humans causes hyperaminoacidemia and islet alpha cell expansion combined with pancreatic hypertrophy. Notably, a recent report showed that the restoration of glucagon resistance by liver transplantation resolved not only hyperglucagonemia, but also pancreatic hypertrophy and other metabolic disorders. The mechanisms that regulate islet cell proliferation by amino acids largely remain unelucidated. Clarification of such mechanisms will increase our understanding of the pathophysiology of diseases related to glucagon.
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Affiliation(s)
- Yoshitaka Hayashi
- Department of Endocrinology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-Ku, Nagoya, 464-8601 Japan
- Department of Endocrinology, Nagoya University Graduate School of Medicine, Nagoya University, Nagoya, Japan
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5
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McGlone ER, Bloom SR, Tan TMM. Glucagon resistance and metabolic-associated steatotic liver disease: a review of the evidence. J Endocrinol 2024; 261:e230365. [PMID: 38579751 PMCID: PMC11067060 DOI: 10.1530/joe-23-0365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 04/03/2024] [Indexed: 04/07/2024]
Abstract
Metabolic-associated steatotic liver disease (MASLD) is closely associated with obesity. MASLD affects over 1 billion adults globally but there are few treatment options available. Glucagon is a key metabolic regulator, and its actions include the reduction of liver fat through direct and indirect means. Chronic glucagon signalling deficiency is associated with hyperaminoacidaemia, hyperglucagonaemia and increased circulating levels of glucagon-like peptide 1 (GLP-1) and fibroblast growth factor 21 (FGF-21). Reduction in glucagon activity decreases hepatic amino acid and triglyceride catabolism; metabolic effects include improved glucose tolerance, increased plasma cholesterol and increased liver fat. Conversely, glucagon infusion in healthy volunteers leads to increased hepatic glucose output, decreased levels of plasma amino acids and increased urea production, decreased plasma cholesterol and increased energy expenditure. Patients with MASLD share many hormonal and metabolic characteristics with models of glucagon signalling deficiency, suggesting that they could be resistant to glucagon. Although there are few studies of the effects of glucagon infusion in patients with obesity and/or MASLD, there is some evidence that the expected effect of glucagon on amino acid catabolism may be attenuated. Taken together, this evidence supports the notion that glucagon resistance exists in patients with MASLD and may contribute to the pathogenesis of MASLD. Further studies are warranted to investigate the direct effects of glucagon on metabolism in patients with MASLD.
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Affiliation(s)
- Emma Rose McGlone
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Tricia M-M Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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6
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Heyns IM, Arora M, Ganugula R, Allamreddy SR, Tiwari S, Shah DK, Basu R, Ravi Kumar MNV. Polyester Nanoparticles with Controlled Topography for Peroral Drug Delivery Using Insulin as a Model Protein. ACS NANO 2024; 18:11863-11875. [PMID: 38622996 PMCID: PMC11145941 DOI: 10.1021/acsnano.4c01027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Receptor-mediated polyester drug delivery systems have tremendous potential for improving the clinical performance of existing pharmaceutical drugs. Despite significant progress made in this area, it remains unclear how and to what extent the polyester nanoparticle surface topography would affect the in vitro, ex vivo and in vivo performance of a drug, and if there exists a correlation between in vitro and in vivo, as well as healthy versus pathophysiological states. Herein, we report a systematic investigation of the interactions between ligands and receptors as a function of the linker length, two-carbon (2C) versus four-carbon (4C). The in vitro, ex vivo and in vivo in healthy models validate the hypothesis that 4C has better reach and binding to the receptors. The results indicate that 4C offered better performance over 2C in vivo in improving the oral bioavailability of insulin (INS) by 1.1-fold (3.5-fold compared to unfunctionalized nanoparticles) in a healthy rat model. Similar observations were made in pathophysiological models; however, the effects were less prominent compared to those in healthy models. Throughout, ligand decorated nanoparticles outperformed unfunctionalized nanoparticles. Finally, a semimechanistic pharmacokinetic and pharmacodynamic (PKPD) model was developed using the experimental data sets to quantitatively evaluate the effect of P2Ns-GA on oral bioavailability and efficacy of insulin. The study presents a sophisticated oral delivery system for INS or hydrophilic therapeutic cargo, highlighting the significant impact on bioavailability that minor adjustments to the surface chemistry can have.
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Affiliation(s)
- Ingrid Marie Heyns
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, AL 35401, United States
- Division of Translational Science and Medicine, College of Community Health Sciences, The University of Alabama, Tuscaloosa, AL 35401, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, AL 35401, United States
| | - Meenakshi Arora
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, AL 35401, United States
- Division of Translational Science and Medicine, College of Community Health Sciences, The University of Alabama, Tuscaloosa, AL 35401, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, AL 35401, United States
- Department of Biological Sciences, The University of Alabama, SEC 1325, Tuscaloosa, AL 35487, United States
| | - Raghu Ganugula
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, AL 35401, United States
- Division of Translational Science and Medicine, College of Community Health Sciences, The University of Alabama, Tuscaloosa, AL 35401, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, AL 35401, United States
- Department of Biological Sciences, The University of Alabama, SEC 1325, Tuscaloosa, AL 35487, United States
| | - Swetha Reddy Allamreddy
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, AL 35401, United States
- Division of Translational Science and Medicine, College of Community Health Sciences, The University of Alabama, Tuscaloosa, AL 35401, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, AL 35401, United States
| | - Shrusti Tiwari
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, The State University of New York at Buffalo, 455 Pharmacy Building, Buffalo, NY 14214, United States
| | - Dhaval K. Shah
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, The State University of New York at Buffalo, 455 Pharmacy Building, Buffalo, NY 14214, United States
| | - Rita Basu
- Division of Endocrinology, Diabetes, and Metabolism, School of Medicine, Marnix E. Heersink School of Medicine, The University of Alabama, Birmingham, AL 35294, United States
| | - M. N. V. Ravi Kumar
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, AL 35401, United States
- Division of Translational Science and Medicine, College of Community Health Sciences, The University of Alabama, Tuscaloosa, AL 35401, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, AL 35401, United States
- Department of Biological Sciences, The University of Alabama, SEC 1325, Tuscaloosa, AL 35487, United States
- Chemical and Biological Engineering, University of Alabama, SEC 3448, Tuscaloosa, AL 35487, United States
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
- Nephrology Research and Training Center, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States
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7
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Oropeza D, Herrera PL. Glucagon-producing α-cell transcriptional identity and reprogramming towards insulin production. Trends Cell Biol 2024; 34:180-197. [PMID: 37626005 DOI: 10.1016/j.tcb.2023.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/07/2023] [Accepted: 07/11/2023] [Indexed: 08/27/2023]
Abstract
β-Cell replacement by in situ reprogramming of non-β-cells is a promising diabetes therapy. Following the observation that near-total β-cell ablation in adult mice triggers the reprogramming of pancreatic α-, δ-, and γ-cells into insulin (INS)-producing cells, recent studies are delving deep into the mechanisms controlling adult α-cell identity. Systematic analyses of the α-cell transcriptome and epigenome have started to pinpoint features that could be crucial for maintaining α-cell identity. Using different transgenic and chemical approaches, significant advances have been made in reprogramming α-cells in vivo into INS-secreting cells in mice. The recent reprogramming of human α-cells in vitro is an important step forward that must now be complemented with a comprehensive molecular dissection of the mechanisms controlling α-cell identity.
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Affiliation(s)
- Daniel Oropeza
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pedro Luis Herrera
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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8
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Ferreira B, Heredia A, Serpa J. An integrative view on glucagon function and putative role in the progression of pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC). Mol Cell Endocrinol 2023; 578:112063. [PMID: 37678603 DOI: 10.1016/j.mce.2023.112063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/16/2023] [Accepted: 09/02/2023] [Indexed: 09/09/2023]
Abstract
Cancer metabolism research area evolved greatly, however, is still unknown the impact of systemic metabolism control and diet on cancer. It makes sense that systemic regulators of metabolism can act directly on cancer cells and activate signalling, prompting metabolic remodelling needed to sustain cancer cell survival, tumour growth and disease progression. In the present review, we describe the main glucagon functions in the control of glycaemia and of metabolic pathways overall. Furthermore, an integrative view on how glucagon and related signalling pathways can contribute for pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC) progression, since pancreas and liver are the major organs exposed to higher levels of glucagon, pancreas as a producer and liver as a scavenger. The main objective is to bring to discussion some glucagon-dependent mechanisms by presenting an integrative view on microenvironmental and systemic aspects in pNETs and HCC biology.
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Affiliation(s)
- Bárbara Ferreira
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal
| | - Adrián Heredia
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal; Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz MB, 1649-028, Lisboa, Portugal
| | - Jacinta Serpa
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal.
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9
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Liu T, Khanal S, Hertslet GD, Lamichhane R. Single-molecule analysis reveals that a glucagon-bound extracellular domain of the glucagon receptor is dynamic. J Biol Chem 2023; 299:105160. [PMID: 37586587 PMCID: PMC10514447 DOI: 10.1016/j.jbc.2023.105160] [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: 02/13/2023] [Revised: 08/07/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Dynamic information is vital to understanding the activation mechanism of G protein-coupled receptors (GPCRs). Despite the availability of high-resolution structures of different conformational states, the dynamics of those states at the molecular level are poorly understood. Here, we used total internal reflection fluorescence microscopy to study the extracellular domain (ECD) of the glucagon receptor (GCGR), a class B family GPCR that controls glucose homeostasis. Single-molecule fluorescence resonance energy transfer was used to observe the ECD dynamics of GCGR molecules expressed and purified from mammalian cells. We observed that for apo-GCGR, the ECD is dynamic and spent time predominantly in a closed conformation. In the presence of glucagon, the ECD is wide open and also shows more dynamic behavior than apo-GCGR, a finding that was not previously reported. These results suggest that both apo-GCGR and glucagon-bound GCGRs show reversible opening and closing of the ECD with respect to the seven-transmembrane (7TM) domain. This work demonstrates a molecular approach to visualizing the dynamics of the GCGR ECD and provides a foundation for understanding the conformational changes underlying GPCR activation, which is critical in the development of new therapeutics.
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Affiliation(s)
- Ting Liu
- Department of Biochemistry & Cellular and Molecular Biology, College of Arts & Sciences, University of Tennessee, Knoxville, Tennessee, USA
| | - Susmita Khanal
- Department of Biochemistry & Cellular and Molecular Biology, College of Arts & Sciences, University of Tennessee, Knoxville, Tennessee, USA
| | - Gillian D Hertslet
- Department of Biochemistry & Cellular and Molecular Biology, College of Arts & Sciences, University of Tennessee, Knoxville, Tennessee, USA
| | - Rajan Lamichhane
- Department of Biochemistry & Cellular and Molecular Biology, College of Arts & Sciences, University of Tennessee, Knoxville, Tennessee, USA.
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10
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Humbert A, Lefebvre R, Nawrot M, Caussy C, Rieusset J. Calcium signalling in hepatic metabolism: Health and diseases. Cell Calcium 2023; 114:102780. [PMID: 37506596 DOI: 10.1016/j.ceca.2023.102780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023]
Abstract
The flexibility between the wide array of hepatic functions relies on calcium (Ca2+) signalling. Indeed, Ca2+ is implicated in the control of many intracellular functions as well as intercellular communication. Thus, hepatocytes adapt their Ca2+ signalling depending on their nutritional and hormonal environment, leading to opposite cellular functions, such as glucose storage or synthesis. Interestingly, hepatic metabolic diseases, such as obesity, type 2 diabetes and non-alcoholic fatty liver diseases, are associated with impaired Ca2+ signalling. Here, we present the hepatocytes' toolkit for Ca2+ signalling, complete with regulation systems and signalling pathways activated by nutrients and hormones. We further discuss the current knowledge on the molecular mechanisms leading to alterations of Ca2+ signalling in hepatic metabolic diseases, and review the literature on the clinical impact of Ca2+-targeting therapeutics.
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Affiliation(s)
- Alexandre Humbert
- Laboratoire CarMeN, INSERM U-1060, INRAE U-1397, Université Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Rémy Lefebvre
- Laboratoire CarMeN, INSERM U-1060, INRAE U-1397, Université Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Margaux Nawrot
- Laboratoire CarMeN, INSERM U-1060, INRAE U-1397, Université Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France
| | - Cyrielle Caussy
- Laboratoire CarMeN, INSERM U-1060, INRAE U-1397, Université Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France; Département Endocrinologie, Diabète et Nutrition, Hospices Civils de Lyon, Hôpital Lyon Sud, Pierre-Bénite, France
| | - Jennifer Rieusset
- Laboratoire CarMeN, INSERM U-1060, INRAE U-1397, Université Lyon, Université Claude Bernard Lyon 1, Pierre-Bénite, France.
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11
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Ray A. Retatrutide: a triple incretin receptor agonist for obesity management. Expert Opin Investig Drugs 2023; 32:1003-1008. [PMID: 37902090 DOI: 10.1080/13543784.2023.2276754] [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: 08/20/2023] [Accepted: 10/25/2023] [Indexed: 10/31/2023]
Abstract
INTRODUCTION Obesity treatment is evolving rapidly with the emergence of agents targeting incretin receptors. Retatrutide, a triple agonist of these receptors, shows promise in obesity management. AREAS COVERED Retatrutide, in phase-2 trials, exhibited significant reductions in glycated hemoglobin (HbA1c) and dose-dependent weight loss in individuals with type 2 diabetes mellitus (T2DM). In non-T2DM individuals, it produced substantial weight loss and improved glucose levels, albeit with gastrointestinal side effects. The role of glucagon receptor agonism in the management of heart failure and its potential impact on eating patterns have also been covered in this article. EXPERT OPINION Although the reductions in HbA1c and dose-dependent weight loss among individuals with T2DM were significantly more for higher doses of retatrutide, it needs to be observed that the active comparator was dulaglutide, which is not approved for the treatment of obesity, at a dose of 1.5 mg, which is much lower than the highest approved dose of 4.5 mg. Dose-dependent increase in heart rate and incidents of mild to moderate cardiac arrythmias raise cardiovascular safety concerns and signify that carrying out long-term cardiovascular outcome trials (CVOTs) will be critical. In addition, retatrutide's potential in heart failure management is intriguing given the series of positive findings of semaglutide on cardiovascular outcomes.
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Affiliation(s)
- Avik Ray
- Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
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12
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Lafferty R, Tanday N, Dubey V, Coulter-Parkhill A, Vishal K, Moffett RC, O'Harte F, Flatt PR, Irwin N. The glucagon receptor antagonist desHis 1Pro 4Glu 9-glucagon(Lys 12PAL) alters alpha-cell turnover and lineage in mice, but does not cause alpha-cell hyperplasia. Mol Cell Endocrinol 2023; 570:111932. [PMID: 37080378 DOI: 10.1016/j.mce.2023.111932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/24/2023] [Accepted: 04/16/2023] [Indexed: 04/22/2023]
Abstract
OBJECTIVE Glucagon receptor (GCGR) antagonism elicits antihyperglycemic effects in rodents and humans. The present study investigates whether the well characterised peptide-based GCGR antagonist, desHis1Pro4Glu9-glucagon (Lys12PAL), alters alpha-cell turnover or identity in mice. METHODS Multiple low-dose streptozotocin (STZ) treated (50 mg/kg bw, 5 days) transgenic GluCreERT2;ROSA26-eYFP mice were employed. STZ mice received twice daily administration of saline vehicle or desHis1Pro4Glu9-glucagon (Lys12PAL), at low- or high-dose (25 and 100 nmol/kg, respectively) for 11 days. RESULTS No GCGR antagonist induced changes in food or fluid intake, body weight or glucose homeostasis were observed. As expected, STZ dramatically reduced (P < 0.001) islet numbers and increased (P < 0.01) alpha-to beta-cell ratio, which was linked to elevated (P < 0.05) levels of beta-cell apoptosis. Whilst treatment with desHis1Pro4Glu9-glucagon (Lys12PAL) decreased (P < 0.05-P < 0.001) alpha- and beta-cell areas, it also helped restore the classic rodent islet alpha-cell mantle in STZ mice. Interestingly, low-dose desHis1Pro4Glu9-glucagon (Lys12PAL) increased (P < 0.05) alpha-cell apoptosis rates whilst high dose decreased (p < 0.05) this parameter. This difference reflects substantially increased (P < 0.001) alpha-to beta-cell transdifferentiation following high dose desHis1Pro4Glu9-glucagon (Lys12PAL) treatment, which was not fully manifest with low-dose therapy. CONCLUSIONS Taken together, the present study indicates that peptidic GCGR antagonists can positively influence alpha-cell turnover and lineage in identity in multiple low-dose STZ mice, but that such effects are dose-related.
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Affiliation(s)
- Ryan Lafferty
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Neil Tanday
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Vaibhav Dubey
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | | | - Karthick Vishal
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | | | - Finbarr O'Harte
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK.
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13
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Ganugula R, Arora M, Dwivedi S, Chandrashekar DS, Varambally S, Scott EM, Kumar MNVR. Systemic Anti-Inflammatory Therapy Aided by Curcumin-Laden Double-Headed Nanoparticles Combined with Injectable Long-Acting Insulin in a Rodent Model of Diabetes Eye Disease. ACS NANO 2023; 17:6857-6874. [PMID: 36951721 DOI: 10.1021/acsnano.3c00535] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Therapeutic interventions that counter emerging targets in diabetes eye diseases are lacking. We hypothesize that a combination therapy targeting inflammation and hyperglycemia can prevent diabetic eye diseases. Here, we report a multipronged approach to prevent diabetic cataracts and retinopathy by combining orally bioavailable curcumin-laden double-headed (two molecules of gambogic acid conjugated to terminal carboxyl groups of poly(d,l-lactide-co-glycolide)) nanoparticles and injectable basal insulin. The combination treatment led to a significant delay in the progression of diabetic cataracts and retinopathy, improving liver function and peripheral glucose homeostasis. We found a concurrent reduction in lens aggregate protein, AGEs, and increased mitochondrial ATP production. Importantly, inhibition of Piezo1 protected against hyperglycemia-induced retinal vascular damage suggesting possible involvement of Piezo1 in the regulation of retinal phototransduction. Histologic evaluation of murine small intestines revealed that chronic administration of curcumin-laden double-headed nanoparticles was well tolerated, circumventing the fear of nanoparticle toxicity. These findings establish the potential of anti-inflammatory and anti-hyperglycemic combination therapy for the prevention of diabetic cataracts and retinopathy.
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Affiliation(s)
- R Ganugula
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Bioscience and Medicine Initiative, College of Community Health Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Department of Biological Sciences, The University of Alabama, SEC 1325, Box 870344, Tuscaloosa, Alabama 35487, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - M Arora
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Bioscience and Medicine Initiative, College of Community Health Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Department of Biological Sciences, The University of Alabama, SEC 1325, Box 870344, Tuscaloosa, Alabama 35487, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - S Dwivedi
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Bioscience and Medicine Initiative, College of Community Health Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - D S Chandrashekar
- Genomic Diagnostics and Bioinformatics, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35233, United States
| | - S Varambally
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35233, United States
| | - E M Scott
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, 930 Campus Road, Ithaca, New York 14853, United States
| | - M N V Ravi Kumar
- The Center for Convergent Bioscience and Medicine (CCBM), The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Bioscience and Medicine Initiative, College of Community Health Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Department of Biological Sciences, The University of Alabama, SEC 1325, Box 870344, Tuscaloosa, Alabama 35487, United States
- Alabama Life Research Institute, The University of Alabama, Tuscaloosa, Alabama 35487, United States
- Department of Pharmaceutical Sciences, Irma Lerma Rangel College of Pharmacy, Texas A&M University, College Station, Texas 77843, United States
- Chemical and Biological Engineering, University of Alabama, SEC 3448, Box 870203, Tuscaloosa, Alabama 35487, United States
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Nephrology Research and Training Center, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
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14
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Arble DM, Hutch CR, Hafner H, Stelmak D, Leix K, Sorrell J, Pressler JW, Gregg B, Sandoval DA. The role of preproglucagon peptides in regulating β-cell morphology and responses to streptozotocin-induced diabetes. Am J Physiol Endocrinol Metab 2023; 324:E217-E225. [PMID: 36652401 PMCID: PMC9970646 DOI: 10.1152/ajpendo.00152.2022] [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: 06/27/2022] [Revised: 11/29/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023]
Abstract
Insulin secretion from β-cells is tightly regulated by local signaling from preproglucagon (Gcg) products from neighboring α-cells. Physiological paracrine signaling within the microenvironment of the β-cell is altered after metabolic stress, such as high-fat diet or the β-cell toxin, streptozotocin (STZ). Here, we examined the role and source of Gcg peptides in β-cell function and in response to STZ-induced hyperglycemia. We used whole body Gcg null (GcgNull) mice and mice with Gcg expression either specifically within the pancreas (GcgΔPanc) or the intestine (GcgΔIntest). With lower doses of STZ exposure, insulin levels were greater and glucose levels were lower in GcgNull mice compared with wild-type mice. When Gcg was functional only in the intestine, plasma glucagon-like peptide-1 (GLP-1) levels were fully restored but these mice did not have any additional protection from STZ-induced diabetes. Pancreatic Gcg reactivation normalized the hyperglycemic response to STZ. In animals not treated with STZ, GcgNull mice had increased pancreas mass via both α- and β-cell hyperplasia and reactivation of Gcg in the intestine normalized β- but not α-cell mass, whereas pancreatic reactivation normalized both β- and α-cell mass. GcgNull and GcgΔIntest mice maintained higher β-cell mass after treatment with STZ compared with control and GcgΔPanc mice. Although in vivo insulin response to glucose was normal, global lack of Gcg impaired glucose-stimulated insulin secretion in isolated islets. Congenital replacement of Gcg either in the pancreas or intestine normalized glucose-stimulated insulin secretion. Interestingly, mice that had intestinal Gcg reactivated in adulthood had impaired insulin response to KCl. We surmise that the expansion of β-cell mass in the GcgNull mice compensated for decreased individual β-cell insulin secretion, which is sufficient to normalize glucose under physiological conditions and conferred some protection after STZ-induced diabetes.NEW & NOTEWORTHY We examined the role of Gcg on β-cell function under normal and high glucose conditions. GcgNull mice had decreased glucose-stimulated insulin secretion, increased β-cell mass, and partial protection against STZ-induced hyperglycemia. Expression of Gcg within the pancreas normalized these endpoints. Intestinal expression of Gcg only normalized β-cell mass and glucose-stimulated insulin secretion. Increased β-cell mass in GcgNull mice likely compensated for decreased insulin secretion normalizing physiological glucose levels and conferring some protection after STZ-induced diabetes.
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Affiliation(s)
- Deanna M Arble
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, United States
| | - Chelsea R Hutch
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, United States
| | - Hannah Hafner
- Department of Pediatrics, Division of Diabetes, Endocrinology and Metabolism, University of Michigan Medicine, Ann Arbor, Michigan, United States
| | - Daria Stelmak
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, United States
| | - Kyle Leix
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, United States
| | - Joyce Sorrell
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - Joshua W Pressler
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States
| | - Brigid Gregg
- Department of Pediatrics, Division of Diabetes, Endocrinology and Metabolism, University of Michigan Medicine, Ann Arbor, Michigan, United States
| | - Darleen A Sandoval
- Department of Pediatrics, Section of Nutrition and Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
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15
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Yang H, Zhang Y, Du Z, Wu T, Yang C. Hair follicle mesenchymal stem cell exosomal lncRNA H19 inhibited NLRP3 pyroptosis to promote diabetic mouse skin wound healing. Aging (Albany NY) 2023; 15:791-809. [PMID: 36787444 PMCID: PMC9970314 DOI: 10.18632/aging.204513] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 02/02/2023] [Indexed: 02/16/2023]
Abstract
Skin wounds caused by diabetes are a major medical problem. Mesenchymal stem cell-derived exosomes hold promise to quicken wound healing due to their ability to transfer certain molecules to target cells, including mRNAs, microRNAs, lncRNAs, and proteins. Nonetheless, the specific mechanisms underlying this impact are not elucidated. Therefore, this research aimed to investigate the effect of MSC-derived exosomes comprising long non-coding RNA (lncRNA) H19 on diabetic skin wound healing. Hair follicle mesenchymal stem cells (HF-MSCs) were effectively isolated and detected, and exosomes (Exo) were also isolated smoothly. Pretreatment with 30 mM glucose for 24 h (HG) could efficiently induce pyroptosis in HaCaT cells. Exosomal H19 enhanced HaCaT proliferation and migration and inhibited pyroptosis by reversing the stimulation of the NLRP3 inflammasome. Injection of exosomes overexpressing lncRNA H19 to diabetic skin wound promoted sustained skin wound healing, whereas sh-H19 exosomes did not have this effect. In conclusion, Exosomes overexpressing H19 promoted HaCaT proliferation, migration and suppressed pyroptosis both in vitro and in vivo. Therefore, HFMSC-derived exosomes that overexpress H19 may be included in strategies for healing diabetic skin wounds.
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Affiliation(s)
- Hongliang Yang
- Department of Cardiology, China-Japan Union Hospital of Jilin University, Changchun 130031, China
| | - Yan Zhang
- School of Public Health, Beihua University, Jilin 132033, China
| | - Zhenwu Du
- Department of Cardiology, China-Japan Union Hospital of Jilin University, Changchun 130031, China
| | - Tengfei Wu
- Department of Laboratory Animal Science, China Medical University, Shenyang 110122, China
| | - Chun Yang
- College of Basic Medicine, Beihua University, Jilin 132033, China
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16
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Wang K, Cui X, Li F, Xia L, Wei T, Liu J, Fu W, Yang J, Hong T, Wei R. Glucagon receptor blockage inhibits β-cell dedifferentiation through FoxO1. Am J Physiol Endocrinol Metab 2023; 324:E97-E113. [PMID: 36383639 DOI: 10.1152/ajpendo.00101.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glucagon-secreting pancreatic α-cells play pivotal roles in the development of diabetes. Glucagon promotes insulin secretion from β-cells. However, the long-term effect of glucagon on the function and phenotype of β-cells had remained elusive. In this study, we found that long-term glucagon intervention or glucagon intervention with the presence of palmitic acid downregulated β-cell-specific markers and inhibited insulin secretion in cultured β-cells. These results suggested that glucagon induced β-cell dedifferentiation under pathological conditions. Glucagon blockage by a glucagon receptor (GCGR) monoclonal antibody (mAb) attenuated glucagon-induced β-cell dedifferentiation. In primary islets, GCGR mAb treatment upregulated β-cell-specific markers and increased insulin content, suggesting that blockage of endogenous glucagon-GCGR signaling inhibited β-cell dedifferentiation. To investigate the possible mechanism, we found that glucagon decreased FoxO1 expression. FoxO1 inhibitor mimicked the effect of glucagon, whereas FoxO1 overexpression reversed the glucagon-induced β-cell dedifferentiation. In db/db mice and β-cell lineage-tracing diabetic mice, GCGR mAb lowered glucose level, upregulated plasma insulin level, increased β-cell area, and inhibited β-cell dedifferentiation. In aged β-cell-specific FoxO1 knockout mice (with the blood glucose level elevated as a diabetic model), the glucose-lowering effect of GCGR mAb was attenuated and the plasma insulin level, β-cell area, and β-cell dedifferentiation were not affected by GCGR mAb. Our results proved that glucagon induced β-cell dedifferentiation under pathological conditions, and the effect was partially mediated by FoxO1. Our study reveals a novel cross talk between α- and β-cells and is helpful to understand the pathophysiology of diabetes and discover new targets for diabetes treatment.NEW & NOTEWORTHY Glucagon-secreting pancreatic α-cells can interact with β-cells. However, the long-term effect of glucagon on the function and phenotype of β-cells has remained elusive. Our new finding shows that long-term glucagon induces β-cell dedifferentiation in cultured β-cells. FoxO1 inhibitor mimicks whereas glucagon signaling blockage by GCGR mAb reverses the effect of glucagon. In type 2 diabetic mice, GCGR mAb increases β-cell area, improves β-cell function, and inhibits β-cell dedifferentiation, and the effect is partially mediated by FoxO1.
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Affiliation(s)
- Kangli Wang
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Xiaona Cui
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Fei Li
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Li Xia
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Junling Liu
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Wei Fu
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
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17
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Capozzi ME, D'Alessio DA, Campbell JE. The past, present, and future physiology and pharmacology of glucagon. Cell Metab 2022; 34:1654-1674. [PMID: 36323234 PMCID: PMC9641554 DOI: 10.1016/j.cmet.2022.10.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/23/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022]
Abstract
The evolution of glucagon has seen the transition from an impurity in the preparation of insulin to the development of glucagon receptor agonists for use in type 1 diabetes. In type 2 diabetes, glucagon receptor antagonists have been explored to reduce glycemia thought to be induced by hyperglucagonemia. However, the catabolic actions of glucagon are currently being leveraged to target the rise in obesity that paralleled that of diabetes, bringing the pharmacology of glucagon full circle. During this evolution, the physiological importance of glucagon advanced beyond the control of hepatic glucose production, incorporating critical roles for glucagon to regulate both lipid and amino acid metabolism. Thus, it is unsurprising that the study of glucagon has left several paradoxes that make it difficult to distill this hormone down to a simplified action. Here, we describe the history of glucagon from the past to the present and suggest some direction to the future of this field.
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Affiliation(s)
- Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - David A D'Alessio
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology Division, Duke University Medical Center, Durham, NC 27701, USA
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology Division, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA.
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18
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Guo H, Sui C, Ge S, Cai J, Lin D, Guo Y, Wang N, Zhou Y, Ying R, Zha K, Gu T, Zhao Y, Lu Y, An Z. Positive association of glucagon with bone turnover markers in type 2 diabetes: A cross-sectional study. Diabetes Metab Res Rev 2022; 38:e3550. [PMID: 35621313 DOI: 10.1002/dmrr.3550] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/09/2022] [Accepted: 03/24/2022] [Indexed: 11/12/2022]
Abstract
AIMS The osteo-metabolic changes in type 2 diabetes (T2D) patients are intricate and have not been fully revealed. It is not clear whether glucagon is entirely harmful in the pathogenesis of diabetes or a possible endocrine counter-regulation mechanism to reverse some abnormal bone metabolism. This study aimed to investigate the association between glucagon and bone turnover markers (BTMs) in T2D patients. METHODS A total of 3984 T2D participants were involved in a cross-sectional study in Shanghai, China. Serum glucagon was measured to elucidate its associations with intact N-terminal propeptide of type I collagen (P1NP), osteocalcin (OC), and β-C-terminal telopeptide (β-CTX). Glucagon was detected with a radioimmunoassay. Propeptide of type I collagen, OC, and β-CTX were detected using chemiluminescence. The diagnosis of T2D was based on American Diabetes Association criteria. RESULTS The concentration of glucagon was positively correlated with two BTMs [OC-β: 0.034, 95% CI: 0.004, 0.051, p = 0.024; CTX-β: 0.035, 95% CI: 0.004, 0.062, p = 0.024]. The result of P1NP was [P1NP-regression coefficient (β): 0.027, 95% CI: -0.003, 0.049, p = 0.083]. In the glucagon tertiles, P for trend of the BTMs is [P1NP: 0.031; OC: 0.038; CTX: 0.020], respectively. CONCLUSIONS Glucagon had a positive effect on bone metabolism. The concentrations of the three BTMs increased as glucagon concentrations rose. This implied that glucagon might speed up skeletal remodelling, accelerate osteogenesis, and promote the formation of mature bone tissue. At the same time, the osteoclastic process was also accelerated, providing raw materials for osteogenesis to preserve the dynamic balance. In view of the successful use of single-molecule as well as dual/triple agonists, it would be feasible to develop a preparation that would reduce osteoporosis in diabetic patients.
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Affiliation(s)
- Hui Guo
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Chunhua Sui
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shaohong Ge
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Jian Cai
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Dongping Lin
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuyu Guo
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ningjian Wang
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Zhou
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Rong Ying
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Kexi Zha
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Tao Gu
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Yan Zhao
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
| | - Yingli Lu
- Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zengmei An
- Institute and Department of Endocrinology and Metabolism, Huangpu Branch of Shanghai Ninth People's Hospital, Shanghai, China
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19
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Wendt A, Eliasson L. Pancreatic alpha cells and glucagon secretion: Novel functions and targets in glucose homeostasis. Curr Opin Pharmacol 2022; 63:102199. [PMID: 35245797 DOI: 10.1016/j.coph.2022.102199] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/25/2022] [Accepted: 01/31/2022] [Indexed: 11/16/2022]
Abstract
Diabetes is the result of dysregulation of both insulin and glucagon. Still, insulin has attracted much more attention than glucagon. Glucagon is released from alpha cells in the islets of Langerhans in response to low glucose and certain amino acids. Drugs with the primary aim of targeting glucagon signalling are scarce. However, glucagon is often administered to counteract severe hypoglycaemia, and commonly used diabetes medications such as GLP-1 analogues, sulfonylureas and SGLT2-inhibitors also affect alpha cells. Indeed, there are physiological and developmental similarities between the alpha cell and the insulin-secreting beta cell and new data confirm that alpha cells can be converted into insulin-secreting cells. These aspects and attributes, the need to find novel therapies targeting the alpha cell and more are considered in this review.
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Affiliation(s)
- Anna Wendt
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Clinical Research Centre, SUS, Malmö, Sweden
| | - Lena Eliasson
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Clinical Research Centre, SUS, Malmö, Sweden.
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20
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Jia Y, Liu Y, Feng L, Sun S, Sun G. Role of Glucagon and Its Receptor in the Pathogenesis of Diabetes. Front Endocrinol (Lausanne) 2022; 13:928016. [PMID: 35784565 PMCID: PMC9243425 DOI: 10.3389/fendo.2022.928016] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/13/2022] [Indexed: 11/24/2022] Open
Abstract
Various theories for the hormonal basis of diabetes have been proposed and debated over the past few decades. Insulin insufficiency was previously regarded as the only hormone deficiency directly leading to metabolic disorders associated with diabetes. Although glucagon and its receptor are ignored in this framework, an increasing number of studies have shown that they play essential roles in the development and progression of diabetes. However, the molecular mechanisms underlying the effects of glucagon are still not clear. In this review, recent research on the mechanisms by which glucagon and its receptor contribute to the pathogenesis of diabetes as well as correlations between GCGR mutation rates in populations and the occurrence of diabetes are summarized. Furthermore, we summarize how recent research clearly establishes glucagon as a potential therapeutic target for diabetes.
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Affiliation(s)
- Yunbo Jia
- Innovative Engineering Technology Research Center for Cell Therapy, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yang Liu
- Innovative Engineering Technology Research Center for Cell Therapy, Shengjing Hospital of China Medical University, Shenyang, China
| | - Linlin Feng
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Siyu Sun
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
- *Correspondence: Siyu Sun, ; Guangwei Sun,
| | - Guangwei Sun
- Innovative Engineering Technology Research Center for Cell Therapy, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
- *Correspondence: Siyu Sun, ; Guangwei Sun,
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21
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Asadi F, Dhanvantari S. Pathways of Glucagon Secretion and Trafficking in the Pancreatic Alpha Cell: Novel Pathways, Proteins, and Targets for Hyperglucagonemia. Front Endocrinol (Lausanne) 2021; 12:726368. [PMID: 34659118 PMCID: PMC8511682 DOI: 10.3389/fendo.2021.726368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/13/2021] [Indexed: 12/15/2022] Open
Abstract
Patients with diabetes mellitus exhibit hyperglucagonemia, or excess glucagon secretion, which may be the underlying cause of the hyperglycemia of diabetes. Defective alpha cell secretory responses to glucose and paracrine effectors in both Type 1 and Type 2 diabetes may drive the development of hyperglucagonemia. Therefore, uncovering the mechanisms that regulate glucagon secretion from the pancreatic alpha cell is critical for developing improved treatments for diabetes. In this review, we focus on aspects of alpha cell biology for possible mechanisms for alpha cell dysfunction in diabetes: proglucagon processing, intrinsic and paracrine control of glucagon secretion, secretory granule dynamics, and alterations in intracellular trafficking. We explore possible clues gleaned from these studies in how inhibition of glucagon secretion can be targeted as a treatment for diabetes mellitus.
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Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
- Imaging Research Program, Lawson Health Research Institute, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
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22
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Glucagon blockade restores functional β-cell mass in type 1 diabetic mice and enhances function of human islets. Proc Natl Acad Sci U S A 2021; 118:2022142118. [PMID: 33619103 PMCID: PMC7936318 DOI: 10.1073/pnas.2022142118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Both type 1 and type 2 diabetes are associated with reduced β-cell mass or function, resulting from decreased proliferation and increased apoptosis. Understanding the signals governing β-cell survival and regeneration is critical for developing strategies to maintain healthy populations of these cells in individuals. Both forms of diabetes are associated with hyperglucagonemia and an increased plasma glucagon:insulin ratio. Glucagon excess contributes to metabolic dysregulation of the diabetic state and glucagon receptor antagonism is a potential target area for the treatment and prevention of diabetes. Our studies presented here suggest that blockade of glucagon signaling lowers glycemia in mouse models of type 1 diabetes while enhancing formation of functional β-cell mass and production of insulin-positive cells from α-cell precursors. We evaluated the potential for a monoclonal antibody antagonist of the glucagon receptor (Ab-4) to maintain glucose homeostasis in type 1 diabetic rodents. We noted durable and sustained improvements in glycemia which persist long after treatment withdrawal. Ab-4 promoted β-cell survival and enhanced the recovery of insulin+ islet mass with concomitant increases in circulating insulin and C peptide. In PANIC-ATTAC mice, an inducible model of β-cell apoptosis which allows for robust assessment of β-cell regeneration following caspase-8–induced diabetes, Ab-4 drove a 6.7-fold increase in β-cell mass. Lineage tracing suggests that this restoration of functional insulin-producing cells was at least partially driven by α-cell-to-β-cell conversion. Following hyperglycemic onset in nonobese diabetic (NOD) mice, Ab-4 treatment promoted improvements in C-peptide levels and insulin+ islet mass was dramatically increased. Lastly, diabetic mice receiving human islet xenografts showed stable improvements in glycemic control and increased human insulin secretion.
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23
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Acreman S, Zhang Q. Regulation of α-cell glucagon secretion: The role of second messengers. Chronic Dis Transl Med 2021; 8:7-18. [PMID: 35620162 PMCID: PMC9128566 DOI: 10.1016/j.cdtm.2021.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/15/2021] [Indexed: 11/30/2022] Open
Abstract
Glucagon is a potent glucose‐elevating hormone that is secreted by pancreatic α‐cells. While well‐controlled glucagon secretion plays an important role in maintaining systemic glucose homeostasis and preventing hypoglycaemia, it is increasingly apparent that defects in the regulation of glucagon secretion contribute to impaired counter‐regulation and hyperglycaemia in diabetes. It has therefore been proposed that pharmacological interventions targeting glucagon secretion/signalling can have great potential in improving glycaemic control of patients with diabetes. However, despite decades of research, a consensus on the precise mechanisms of glucose regulation of glucagon secretion is yet to be reached. Second messengers are a group of small intracellular molecules that relay extracellular signals to the intracellular signalling cascade, modulating cellular functions. There is a growing body of evidence that second messengers, such as cAMP and Ca2+, play critical roles in α‐cell glucose‐sensing and glucagon secretion. In this review, we discuss the impact of second messengers on α‐cell electrical activity, intracellular Ca2+ dynamics and cell exocytosis. We highlight the possibility that the interaction between different second messengers may play a key role in the glucose‐regulation of glucagon secretion.
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24
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Fan S, Xu Y, Lu Y, Jiang Z, Li H, Morrill JC, Cai J, Wu Q, Xu Y, Xue M, Arenkiel BR, Huang C, Tong Q. A neural basis for brain leptin action on reducing type 1 diabetic hyperglycemia. Nat Commun 2021; 12:2662. [PMID: 33976218 PMCID: PMC8113586 DOI: 10.1038/s41467-021-22940-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/07/2021] [Indexed: 02/07/2023] Open
Abstract
Central leptin action rescues type 1 diabetic (T1D) hyperglycemia; however, the underlying mechanism and the identity of mediating neurons remain elusive. Here, we show that leptin receptor (LepR)-expressing neurons in arcuate (LepRArc) are selectively activated in T1D. Activation of LepRArc neurons, Arc GABAergic (GABAArc) neurons, or arcuate AgRP neurons, is able to reverse the leptin's rescuing effect. Conversely, inhibition of GABAArc neurons, but not AgRP neurons, produces leptin-mimicking rescuing effects. Further, AgRP neuron function is not required for T1D hyperglycemia or leptin's rescuing effects. Finally, T1D LepRArc neurons show defective nutrient sensing and signs of cellular energy deprivation, which are both restored by leptin, whereas nutrient deprivation reverses the leptin action. Our results identify aberrant activation of LepRArc neurons owing to energy deprivation as the neural basis for T1D hyperglycemia and that leptin action is mediated by inhibiting LepRArc neurons through reversing energy deprivation.
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Affiliation(s)
- Shengjie Fan
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yuanzhong Xu
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yungang Lu
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Zhiying Jiang
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Hongli Li
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Jessie C Morrill
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
- MD Anderson Cancer Center & UT Health Graduate School for Biomedical Sciences, University of Texas Health Science at Houston, Houston, TX, USA
| | - Jing Cai
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA
- MD Anderson Cancer Center & UT Health Graduate School for Biomedical Sciences, University of Texas Health Science at Houston, Houston, TX, USA
| | - Qi Wu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
| | - Mingshan Xue
- Department of Neuroscience and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Cheng Huang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Qingchun Tong
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.
- MD Anderson Cancer Center & UT Health Graduate School for Biomedical Sciences, University of Texas Health Science at Houston, Houston, TX, USA.
- Department of Neurobiology and Anatomy of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, USA.
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25
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Fujikawa T. Central regulation of glucose metabolism in an insulin-dependent and -independent manner. J Neuroendocrinol 2021; 33:e12941. [PMID: 33599044 DOI: 10.1111/jne.12941] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 12/17/2022]
Abstract
The central nervous system (CNS) contributes significantly to glucose homeostasis. The available evidence indicates that insulin directly acts on the CNS, in particular the hypothalamus, to regulate hepatic glucose production, thereby controlling whole-body glucose metabolism. Additionally, insulin also acts on the brain to regulate food intake and fat metabolism, which may indirectly regulate glucose metabolism. Studies conducted over the last decade have found that the CNS can regulate glucose metabolism in an insulin-independent manner. Enhancement of central leptin signalling reverses hyperglycaemia in insulin-deficient rodents. Here, I review the mechanisms by which central insulin and leptin actions regulate glucose metabolism. Although clinical studies have shown that insulin treatment is currently indispensable for managing diabetes, unravelling the neuronal mechanisms underlying the central regulation of glucose metabolism will pave the way for the design of novel therapeutic drugs for diabetes.
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Affiliation(s)
- Teppei Fujikawa
- Center for Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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26
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Bozadjieva Kramer N, Lubaczeuski C, Blandino-Rosano M, Barker G, Gittes GK, Caicedo A, Bernal-Mizrachi E. Glucagon Resistance and Decreased Susceptibility to Diabetes in a Model of Chronic Hyperglucagonemia. Diabetes 2021; 70:477-491. [PMID: 33239450 PMCID: PMC7881862 DOI: 10.2337/db20-0440] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 11/18/2020] [Indexed: 02/07/2023]
Abstract
Elevation of glucagon levels and increase in α-cell mass are associated with states of hyperglycemia in diabetes. Our previous studies have highlighted the role of nutrient signaling via mTOR complex 1 (mTORC1) regulation that controls glucagon secretion and α-cell mass. In the current studies we investigated the effects of activation of nutrient signaling by conditional deletion of the mTORC1 inhibitor, TSC2, in α-cells (αTSC2KO). We showed that activation of mTORC1 signaling is sufficient to induce chronic hyperglucagonemia as a result of α-cell proliferation, cell size, and mass expansion. Hyperglucagonemia in αTSC2KO was associated with an increase in glucagon content and enhanced glucagon secretion. This model allowed us to identify the effects of chronic hyperglucagonemia on glucose homeostasis by inducing insulin secretion and resistance to glucagon in the liver. Liver glucagon resistance in αTSC2KO mice was characterized by reduced expression of the glucagon receptor (GCGR), PEPCK, and genes involved in amino acid metabolism and urea production. Glucagon resistance in αTSC2KO mice was associated with improved glucose levels in streptozotocin-induced β-cell destruction and high-fat diet-induced glucose intolerance. These studies demonstrate that chronic hyperglucagonemia can improve glucose homeostasis by inducing glucagon resistance in the liver.
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Affiliation(s)
- Nadejda Bozadjieva Kramer
- Department of Medicine, University of Michigan Medical Center, Ann Arbor, MI
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI
- Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI
| | - Camila Lubaczeuski
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Manuel Blandino-Rosano
- Department of Medicine, University of Michigan Medical Center, Ann Arbor, MI
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Grant Barker
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - George K Gittes
- UPMC Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburg, PA
| | - Alejandro Caicedo
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
| | - Ernesto Bernal-Mizrachi
- Division of Endocrinology, Metabolism and Diabetes, Department of Internal Medicine, Miller School of Medicine, University of Miami, Miami, FL
- Veterans Affairs Medical Center, Miami, FL
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27
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Guo K, Tian Q, Yang L, Zhou Z. The Role of Glucagon in Glycemic Variability in Type 1 Diabetes: A Narrative Review. Diabetes Metab Syndr Obes 2021; 14:4865-4873. [PMID: 34992395 PMCID: PMC8710064 DOI: 10.2147/dmso.s343514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 12/01/2021] [Indexed: 01/20/2023] Open
Abstract
Type 1 diabetes mellitus (T1DM) is a progressive disease as a result of the severe destruction of islet β-cell function, which leads to high glucose variability in patients. However, α-cell function is also compromised in patients with T1DM, characterized by aberrant fasting and postprandial glucagon secretion. According to recent studies, this aberrant glucagon secretion plays an increasing role in hyperglycemia, insulin-induced hypoglycemia and exercise-associated hypoglycemia in patients with T1DM. With application of continuous glucose monitoring system, dozens of metrics enable the assessment of glycemic variability, which is an integral component of glycemic control for patients with T1DM. There is growing evidences to illustrate the contribution of glucagon secretion to the glycemic variability in patients with T1DM, which may promote the development of new treatment strategies aiming to mitigate glycemic variability associated with aberrant glucagon secretion.
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Affiliation(s)
- Keyu Guo
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
| | - Qi Tian
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
| | - Lin Yang
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
- Correspondence: Lin Yang; Zhiguang Zhou Email ;
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, 410011, Hunan, People’s Republic of China
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28
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Capozzi ME, Coch RW, Koech J, Astapova II, Wait JB, Encisco SE, Douros JD, El K, Finan B, Sloop KW, Herman MA, D'Alessio DA, Campbell JE. The Limited Role of Glucagon for Ketogenesis During Fasting or in Response to SGLT2 Inhibition. Diabetes 2020; 69:882-892. [PMID: 32005706 PMCID: PMC7171961 DOI: 10.2337/db19-1216] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/27/2020] [Indexed: 12/18/2022]
Abstract
Glucagon is classically described as a counterregulatory hormone that plays an essential role in the protection against hypoglycemia. In addition to its role in the regulation of glucose metabolism, glucagon has been described to promote ketosis in the fasted state. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a new class of glucose-lowering drugs that act primarily in the kidney, but some reports have described direct effects of SGLT2i on α-cells to stimulate glucagon secretion. Interestingly, SGLT2 inhibition also results in increased endogenous glucose production and ketone production, features common to glucagon action. Here, we directly test the ketogenic role of glucagon in mice, demonstrating that neither fasting- nor SGLT2i-induced ketosis is altered by interruption of glucagon signaling. Moreover, any effect of glucagon to stimulate ketogenesis is severely limited by its insulinotropic actions. Collectively, our data suggest that fasting-associated ketosis and the ketogenic effects of SGLT2 inhibitors occur almost entirely independent of glucagon.
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Affiliation(s)
- Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Reilly W Coch
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
| | - Jepchumba Koech
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Inna I Astapova
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
| | - Jacob B Wait
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Sara E Encisco
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | | | - Kimberly El
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN
| | - Kyle W Sloop
- Diabetes and Complications, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Mark A Herman
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - David A D'Alessio
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
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29
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Abstract
Glucagon and its partner insulin are dually linked in both their secretion from islet cells and their action in the liver. Glucagon signaling increases hepatic glucose output, and hyperglucagonemia is partly responsible for the hyperglycemia in diabetes, making glucagon an attractive target for therapeutic intervention. Interrupting glucagon signaling lowers blood glucose but also results in hyperglucagonemia and α-cell hyperplasia. Investigation of the mechanism for α-cell proliferation led to the description of a conserved liver-α-cell axis where glucagon is a critical regulator of amino acid homeostasis. In return, amino acids regulate α-cell function and proliferation. New evidence suggests that dysfunction of the axis in humans may result in the hyperglucagonemia observed in diabetes. This discussion outlines important but often overlooked roles for glucagon that extend beyond glycemia and supports a new role for α-cells as amino acid sensors.
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Affiliation(s)
- E Danielle Dean
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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30
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Finan B, Capozzi ME, Campbell JE. Repositioning Glucagon Action in the Physiology and Pharmacology of Diabetes. Diabetes 2020; 69:532-541. [PMID: 31178432 PMCID: PMC7085250 DOI: 10.2337/dbi19-0004] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/30/2019] [Indexed: 01/03/2023]
Abstract
Glucagon is historically described as the counterregulatory hormone to insulin, induced by fasting/hypoglycemia to raise blood glucose through action mediated in the liver. However, it is becoming clear that the biology of glucagon is much more complex and extends beyond hepatic actions to exert control on glucose metabolism. We discuss the inconsistencies with the canonical view that glucagon is primarily a hyperglycemic agent driven by fasting/hypoglycemia and highlight the recent advances that have reshaped the metabolic role of glucagon. These concepts are placed within the context of both normal physiology and the pathophysiology of disease and then extended to discuss emerging strategies that incorporate glucagon agonism in the pharmacology of treating diabetes.
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Affiliation(s)
- Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
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31
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Wendt A, Eliasson L. Pancreatic α-cells - The unsung heroes in islet function. Semin Cell Dev Biol 2020; 103:41-50. [PMID: 31983511 DOI: 10.1016/j.semcdb.2020.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 01/15/2023]
Abstract
The pancreatic islets of Langerhans consist of several hormone-secreting cell types important for blood glucose control. The insulin secreting β-cells are the best studied of these cell types, but less is known about the glucagon secreting α-cells. The α-cells secrete glucagon as a response to low blood glucose. The major function of glucagon is to release glucose from the glycogen stores in the liver. In both type 1 and type 2 diabetes, glucagon secretion is dysregulated further exaggerating the hyperglycaemia, and in type 1 diabetes α-cells fail to counter regulate hypoglycaemia. Although glucagon has been recognized for almost 100 years, the understanding of how glucagon secretion is regulated and how glucagon act within the islet is far from complete. However, α-cell research has taken off lately which is promising for future knowledge. In this review we aim to highlight α-cell regulation and glucagon secretion with a special focus on recent discoveries from human islets. We will present some novel aspects of glucagon function and effects of selected glucose lowering agents on glucagon secretion.
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Affiliation(s)
- Anna Wendt
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Clinical Research Centre, SUS, Malmö, Sweden
| | - Lena Eliasson
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Clinical Research Centre, SUS, Malmö, Sweden.
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32
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Global Transcriptomic Analysis of Zebrafish Glucagon Receptor Mutant Reveals Its Regulated Metabolic Network. Int J Mol Sci 2020; 21:ijms21030724. [PMID: 31979106 PMCID: PMC7037442 DOI: 10.3390/ijms21030724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 12/23/2019] [Accepted: 01/20/2020] [Indexed: 12/18/2022] Open
Abstract
The glucagon receptor (GCGR) is a G-protein-coupled receptor (GPCR) that mediates the activity of glucagon. Disruption of GCGR results in many metabolic alterations, including increased glucose tolerance, decreased adiposity, hypoglycemia, and pancreatic α-cell hyperplasia. To better understand the global transcriptomic changes resulting from GCGR deficiency, we performed whole-organism RNA sequencing analysis in wild type and gcgr-deficient zebrafish. We found that the expression of 1645 genes changes more than two-fold among mutants. Most of these genes are related to metabolism of carbohydrates, lipids, and amino acids. Genes related to fatty acid β-oxidation, amino acid catabolism, and ureagenesis are often downregulated. Among gcrgr-deficient zebrafish, we experimentally confirmed increases in lipid accumulation in the liver and whole-body glucose uptake, as well as a modest decrease in total amino acid content. These results provide new information about the global metabolic network that GCGR signaling regulates in addition to a better understanding of the receptor’s physiological functions.
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33
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Gilon P. The Role of α-Cells in Islet Function and Glucose Homeostasis in Health and Type 2 Diabetes. J Mol Biol 2020; 432:1367-1394. [PMID: 31954131 DOI: 10.1016/j.jmb.2020.01.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 01/09/2023]
Abstract
Pancreatic α-cells are the major source of glucagon, a hormone that counteracts the hypoglycemic action of insulin and strongly contributes to the correction of acute hypoglycemia. The mechanisms by which glucose controls glucagon secretion are hotly debated, and it is still unclear to what extent this control results from a direct action of glucose on α-cells or is indirectly mediated by β- and/or δ-cells. Besides its hyperglycemic action, glucagon has many other effects, in particular on lipid and amino acid metabolism. Counterintuitively, glucagon seems also required for an optimal insulin secretion in response to glucose by acting on its cognate receptor and, even more importantly, on GLP-1 receptors. Patients with diabetes mellitus display two main alterations of glucagon secretion: a relative hyperglucagonemia that aggravates hyperglycemia, and an impaired glucagon response to hypoglycemia. Under metabolic stress states, such as diabetes, pancreatic α-cells also secrete GLP-1, a glucose-lowering hormone, whereas the gut can produce glucagon. The contribution of extrapancreatic glucagon to the abnormal glucose homeostasis is unclear. Here, I review the possible mechanisms of control of glucagon secretion and the role of α-cells on islet function in healthy state. I discuss the possible causes of the abnormal glucagonemia in diabetes, with particular emphasis on type 2 diabetes, and I briefly comment the current antidiabetic therapies affecting α-cells.
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Affiliation(s)
- Patrick Gilon
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, Avenue Hippocrate 55 (B1.55.06), Brussels, B-1200, Belgium.
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34
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Zouhar P, Rakipovski G, Bokhari MH, Busby O, Paulsson JF, Conde-Frieboes KW, Fels JJ, Raun K, Andersen B, Cannon B, Nedergaard J. UCP1-independent glucose-lowering effect of leptin in type 1 diabetes: only in conditions of hypoleptinemia. Am J Physiol Endocrinol Metab 2020; 318:E72-E86. [PMID: 31743040 PMCID: PMC6985793 DOI: 10.1152/ajpendo.00253.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The possibility to use leptin therapeutically for lowering glucose levels in patients with type 1 diabetes has attracted interest. However, earlier animal models of type 1 diabetes are severely catabolic with very low endogenous leptin levels, unlike most patients with diabetes. Here, we aim to test glucose-lowering effects of leptin in novel, more human-like murine models. We examined the glucose-lowering potential of leptin in diabetic models of two types: streptozotocin-treated mice and mice treated with the insulin receptor antagonist S961. To prevent hypoleptinemia, we used combinations of thermoneutral temperature and high-fat feeding. Leptin fully normalized hyperglycemia in standard chow-fed streptozotocin-treated diabetic mice. However, more humanized physiological conditions (high-fat diets or thermoneutral temperatures) that increased adiposity - and thus also leptin levels - in the diabetic mice abrogated the effects of leptin, i.e., the mice developed leptin resistance also in this respect. The glucose-lowering effect of leptin was not dependent on the presence of the uncoupling protein-1 and was not associated with alterations in plasma insulin, insulin-like growth factor 1, food intake or corticosterone but fully correlated with decreased plasma glucagon levels and gluconeogenesis. An important implication of these observations is that the therapeutic potential of leptin as an additional treatment in patients with type 1 diabetes is probably limited. This is because such patients are treated with insulin and do not display low leptin levels. Thus, the potential for a glucose-lowering effect of leptin would already have been attained with standard insulin therapy, and further effects on blood glucose level through additional leptin cannot be anticipated.
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Affiliation(s)
- Petr Zouhar
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Department of Adipose Tissue Biology, Institute of Physiology CAS, Prague, the Czech Republic
| | | | - Muhammad Hamza Bokhari
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Oliver Busby
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | | | | | | | - Kirsten Raun
- Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | | | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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35
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Grandl G, Novikoff A, DiMarchi R, Tschöp MH, Müller TD. Gut Peptide Agonism in the Treatment of Obesity and Diabetes. Compr Physiol 2019; 10:99-124. [PMID: 31853954 DOI: 10.1002/cphy.c180044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Obesity is a global healthcare challenge that gives rise to devastating diseases such as the metabolic syndrome, type-2 diabetes (T2D), and a variety of cardiovascular diseases. The escalating prevalence of obesity has led to an increased interest in pharmacological options to counteract excess weight gain. Gastrointestinal hormones such as glucagon, amylin, and glucagon-like peptide-1 (GLP-1) are well recognized for influencing food intake and satiety, but the therapeutic potential of these native peptides is overall limited by a short half-life and an often dose-dependent appearance of unwanted effects. Recent clinical success of chemically optimized GLP-1 mimetics with improved pharmacokinetics and sustained action has propelled pharmacological interest in using bioengineered gut hormones to treat obesity and diabetes. In this article, we summarize the basic biology and signaling mechanisms of selected gut peptides and discuss how they regulate systemic energy and glucose metabolism. Subsequently, we focus on the design and evaluation of unimolecular drugs that combine the beneficial effects of selected gut hormones into a single entity to optimize the beneficial impact on systems metabolism. © 2020 American Physiological Society. Compr Physiol 10:99-124, 2020.
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Affiliation(s)
- Gerald Grandl
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Aaron Novikoff
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Richard DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Matthias H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany.,Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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36
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Wewer Albrechtsen NJ, Pedersen J, Galsgaard KD, Winther-Sørensen M, Suppli MP, Janah L, Gromada J, Vilstrup H, Knop FK, Holst JJ. The Liver-α-Cell Axis and Type 2 Diabetes. Endocr Rev 2019; 40:1353-1366. [PMID: 30920583 DOI: 10.1210/er.2018-00251] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/19/2019] [Indexed: 02/08/2023]
Abstract
Both type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD) strongly associate with increasing body mass index, and together these metabolic diseases affect millions of individuals. In patients with T2D, increased secretion of glucagon (hyperglucagonemia) contributes to diabetic hyperglycemia as proven by the significant lowering of fasting plasma glucose levels following glucagon receptor antagonist administration. Emerging data now indicate that the elevated plasma concentrations of glucagon may also be associated with hepatic steatosis and not necessarily with the presence or absence of T2D. Thus, fatty liver disease, most often secondary to overeating, may result in impaired amino acid turnover, leading to increased plasma concentrations of certain glucagonotropic amino acids (e.g., alanine). This, in turn, causes increased glucagon secretion that may help to restore amino acid turnover and ureagenesis, but it may eventually also lead to increased hepatic glucose production, a hallmark of T2D. Early experimental findings support the hypothesis that hepatic steatosis impairs glucagon's actions on amino acid turnover and ureagenesis. Hepatic steatosis also impairs hepatic insulin sensitivity and clearance that, together with hyperglycemia and hyperaminoacidemia, lead to peripheral hyperinsulinemia; systemic hyperinsulinemia may itself contribute to worsen peripheral insulin resistance. Additionally, obesity is accompanied by an impaired incretin effect, causing meal-related glucose intolerance. Lipid-induced impairment of hepatic sensitivity, not only to insulin but potentially also to glucagon, resulting in both hyperinsulinemia and hyperglucagonemia, may therefore contribute to the development of T2D at least in a subset of individuals with NAFLD.
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Affiliation(s)
- Nicolai J Wewer Albrechtsen
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiology, Nephrology and Endocrinology, Nordsjællands Hospital Hillerød, University of Copenhagen, Hillerød, Denmark
| | - Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Malte P Suppli
- Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark
| | - Lina Janah
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Filip K Knop
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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37
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Wei R, Gu L, Yang J, Yang K, Liu J, Le Y, Lang S, Wang H, Thai D, Yan H, Hong T. Antagonistic Glucagon Receptor Antibody Promotes α-Cell Proliferation and Increases β-Cell Mass in Diabetic Mice. iScience 2019; 16:326-339. [PMID: 31203188 PMCID: PMC6581654 DOI: 10.1016/j.isci.2019.05.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/28/2019] [Accepted: 05/22/2019] [Indexed: 12/19/2022] Open
Abstract
Under extreme conditions or by genetic modification, pancreatic α-cells can regenerate and be converted into β-cells. This regeneration holds substantial promise for cell replacement therapy in diabetic patients. The discovery of clinical therapeutic strategies to promote β-cell regeneration is crucial for translating these findings into clinical applications. In this study, we reported that treatment with REMD 2.59, a human glucagon receptor (GCGR) monoclonal antibody (mAb), lowered blood glucose without inducing hypoglycemia in normoglycemic, streptozotocin-induced type 1 diabetic (T1D) and non-obesity diabetic mice. Moreover, GCGR mAb treatment increased the plasma glucagon and active glucagon-like peptide-1 levels, induced pancreatic ductal ontogenic α-cell neogenesis, and promoted α-cell proliferation. Strikingly, the treatment also increased the β-cell mass in these two T1D models. Using α-cell lineage-tracing mice, we found that the neogenic β-cells were likely derived from α-cell conversion. Therefore, GCGR mAb-induced α- to β-cell conversion might represent a pre-clinical approach for improving diabetes therapy. GCGR mAb induced α-cell expansion by neogenesis and cell proliferation GCGR mAb increased the β-cell mass in type 1 diabetic mice GCGR mAb might promote α- to β-cell conversion in type 1 diabetic mice
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Affiliation(s)
- Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Liangbiao Gu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Kun Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Junling Liu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Yunyi Le
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Shan Lang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Haining Wang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Dung Thai
- REMD Biotherapeutics, Camarillo, CA 93012, USA; Beijing Cosci-REMD, Beijing 102206, China
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA 93012, USA; Beijing Cosci-REMD, Beijing 102206, China
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China.
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38
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Singha AK, Yamaguchi J, Gonzalez NS, Ahmed N, Toney GM, Fujikawa T. Glucose-Lowering by Leptin in the Absence of Insulin Does Not Fully Rely on the Central Melanocortin System in Male Mice. Endocrinology 2019; 160:651-663. [PMID: 30698681 PMCID: PMC6388659 DOI: 10.1210/en.2018-00907] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 01/24/2019] [Indexed: 12/11/2022]
Abstract
Central leptin administration can ameliorate hyperglycemia in insulin-deficient rodent models independently of insulin; however, the underlying neuronal mechanism are unclear. Here, we investigate the contribution of key elements within the central melanocortin system by examining whether central leptin injection can ameliorate hyperglycemia in total insulin-deficient mice that either lacked melanocortin 4 receptors (MC4Rs) in the whole body [knockout (KO); MC4R KO] or selectively, in single-minded homolog 1 (SIM1)-expressing neurons (SIM1ΔMC4R). We further investigated the contribution of leptin receptors (LEPRs) in agouti-related protein (AgRP)-expressing neurons (AgRP∆LEPR). Leptin injections into the cerebral ventricle attenuated mortality and elevated blood glucose in total insulin-deficient MC4R KO mice. Total insulin-deficient SIM1ΔMC4R mice exhibited the same magnitude reduction of blood glucose in response to leptin injections as MC4R KO mice, suggesting SIM1 neurons are key to MC4R-mediated, insulin-independent, glucose-lowering effects of leptin. Central leptin injection also partially rescued glucose levels in total insulin-deficient AgRP∆LEPR mice. In brain slice studies, basal discharge of AgRP neurons from mice with total insulin deficiency was increased and leptin partially reduced their firing rate without membrane potential hyperpolarization. Collectively, our findings indicate that, contrary to glucose-lowering effects of leptin in the presence of insulin or partial insulin deficiency, MC4Rs in SIM1 neurons and LEPRs in AgRP neurons are not solely responsible for glucose-lowering effects of leptin in total insulin deficiency. This indicates that the central melanocortin system operates with other neuronal systems to fully mediate glucose-lowering effects of leptin in an insulin-independent manner.
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Affiliation(s)
- Ashish K Singha
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Junya Yamaguchi
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Nancy S Gonzalez
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Newaz Ahmed
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
- Center for Biomedical Neuroscience, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
| | - Teppei Fujikawa
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
- Center for Biomedical Neuroscience, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
- Mouse Genome Engineering and Transgenic Facility, Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas
- Correspondence: Teppei Fujikawa, PhD, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229. E-mail:
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39
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Furuyama K, Chera S, van Gurp L, Oropeza D, Ghila L, Damond N, Vethe H, Paulo JA, Joosten AM, Berney T, Bosco D, Dorrell C, Grompe M, Ræder H, Roep BO, Thorel F, Herrera PL. Diabetes relief in mice by glucose-sensing insulin-secreting human α-cells. Nature 2019; 567:43-48. [PMID: 30760930 PMCID: PMC6624841 DOI: 10.1038/s41586-019-0942-8] [Citation(s) in RCA: 151] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 01/14/2019] [Indexed: 12/13/2022]
Abstract
Cell identity switches, where terminally-differentiated cells convert into different cell-types when stressed, represent a widespread regenerative strategy in animals, yet they are poorly documented in mammals. In mice, some glucagon-producing pancreatic α-cells and somatostatin-producing δ-cells become insulin expressers upon ablation of insulin-secreting β-cells, promoting diabetes recovery. Whether human islets also display this plasticity, especially in diabetic conditions, remains unknown. Here we show that islet non-β-cells, namely α-cells and PPY-producing γ–cells, obtained from deceased non-diabetic or diabetic human donors, can be lineage-traced and reprogrammed by the transcription factors Pdx1 and MafA to produce and secrete insulin in response to glucose. When transplanted into diabetic mice, converted human α-cells reverse diabetes and remain producing insulin even after 6 months. Surprisingly, insulin-producing α-cells maintain α-cell markers, as seen by deep transcriptomic and proteomic characterization. These observations provide conceptual evidence and a molecular framework for a mechanistic understanding of in situ cell plasticity as a treatment for diabetes and other degenerative diseases.
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Affiliation(s)
- Kenichiro Furuyama
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Simona Chera
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Léon van Gurp
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Daniel Oropeza
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Luiza Ghila
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Nicolas Damond
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Heidrun Vethe
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Antoinette M Joosten
- Department of Immunohematology & Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
| | - Thierry Berney
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals, University of Geneva, Geneva, Switzerland
| | - Craig Dorrell
- Oregon Stem Cell Center, Oregon Health & Science University, Portland, OR, USA
| | - Markus Grompe
- Oregon Stem Cell Center, Oregon Health & Science University, Portland, OR, USA
| | - Helge Ræder
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Bart O Roep
- Department of Immunohematology & Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.,Department of Diabetes Immunology, Diabetes & Metabolism Research Institute, City of Hope, Duarte, CA, USA
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, iGE3 and Centre Facultaire du Diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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40
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Ding W, Chang WG, Guo XC, Liu Y, Xiao DD, Ding D, Wang JX, Zhang XJ. Exenatide Protects Against Cardiac Dysfunction by Attenuating Oxidative Stress in the Diabetic Mouse Heart. Front Endocrinol (Lausanne) 2019; 10:202. [PMID: 31024445 PMCID: PMC6459897 DOI: 10.3389/fendo.2019.00202] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 03/12/2019] [Indexed: 01/01/2023] Open
Abstract
Cardiovascular disease is the major cause of death in patients with diabetes. Current treatment strategies for diabetes rely on lifestyle changes and glucose control to prevent angiopathy and organ failure. Exenatide, a glucagon-like peptide-1 (GLP-1) receptor agonist, is used as an add-on therapy to insulin treatment. Exenatide also has multiple beneficial effects in addition to its hypoglycemic effects, such as preventing hepatic steatosis and protecting against cardiac injury from doxorubicin-induced cardiotoxicity or ischemic reperfusion. However, the mechanisms underlying the cardioprotective effects of exenatide in diabetes have not been fully clarified. To address this issue, we investigated the cardioprotective effects of exenatide in type 1 and type 2 diabetic mice. We found that exenatide simultaneously attenuated reactive oxidative species (ROS) production through increases in the antioxidant enzymes manganese dependent superoxide dismutase (MnSOD) and catalase. Moreover, exenatide decreased tumor protein P53 (p53) expression and prevented cell apoptosis in H9c2 cells. The presence of the catalase inhibitor 3-AT attenuated the effects of exenatide. Overall, the results strongly indicate that exenatide treatment may be protective against the development of diabetic cardiomyopathy.
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Affiliation(s)
- Wei Ding
- Department of General Medicine, The Affiliated Hospital, Qingdao University, Qingdao, China
| | - Wen-guang Chang
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Xiao-ci Guo
- Department of General Medicine, The Affiliated Hospital, Qingdao University, Qingdao, China
| | - Ying Liu
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Dan-dan Xiao
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Dan Ding
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Jian-xun Wang
- Center for Regenerative Medicine, Institute for Translational Medicine, Qingdao University, Qingdao, China
- School of Basic Medical Sciences, Qingdao University, Qingdao, China
- *Correspondence: Jian-xun Wang
| | - Xue-juan Zhang
- Department of General Medicine, The Affiliated Hospital, Qingdao University, Qingdao, China
- Xue-juan Zhang
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41
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Abstract
Findings from the past 10 years have placed the glucagon-secreting pancreatic α-cell centre stage in the development of diabetes mellitus, a disease affecting almost one in every ten adults worldwide. Glucagon secretion is reduced in patients with type 1 diabetes mellitus, increasing the risk of insulin-induced hypoglycaemia, but is enhanced in type 2 diabetes mellitus, exacerbating the effects of diminished insulin release and action on blood levels of glucose. A better understanding of the mechanisms underlying these changes is therefore an important goal. RNA sequencing reveals that, despite their opposing roles in the control of blood levels of glucose, α-cells and β-cells have remarkably similar patterns of gene expression. This similarity might explain the fairly facile interconversion between these cells and the ability of the α-cell compartment to serve as a source of new β-cells in models of extreme β-cell loss that mimic type 1 diabetes mellitus. Emerging data suggest that GABA might facilitate this interconversion, whereas the amino acid glutamine serves as a liver-derived factor to promote α-cell replication and maintenance of α-cell mass. Here, we survey these developments and their therapeutic implications for patients with diabetes mellitus.
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Affiliation(s)
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK.
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42
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Rivero-Gutierrez B, Haller A, Holland J, Yates E, Khrisna R, Habegger K, Dimarchi R, D'Alessio D, Perez-Tilve D. Deletion of the glucagon receptor gene before and after experimental diabetes reveals differential protection from hyperglycemia. Mol Metab 2018; 17:28-38. [PMID: 30170980 PMCID: PMC6197675 DOI: 10.1016/j.molmet.2018.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE Mice with congenital loss of the glucagon receptor gene (Gcgr-/- mice) remain normoglycemic in insulinopenic conditions, suggesting that unopposed glucagon action is the driving force for hyperglycemia in Type-1 Diabetes Mellitus (T1DM). However, chronic loss of GCGR results in a neomorphic phenotype that includes hormonal signals with hypoglycemic activity. We combined temporally-controlled GCGR deletion with pharmacological treatments to dissect the direct contribution of GCGR signaling to glucose control in a common mouse model of T1DM. METHODS We induced experimental T1DM by injecting the beta-cell cytotoxin streptozotocin (STZ) in mice with congenital or temporally-controlled Gcgr loss-of-function using tamoxifen (TMX). RESULTS Disruption of Gcgr expression, using either an inducible approach in adult mice or animals with congenital knockout, abolished the response to a long-acting Gcgr agonist. Mice with either developmental Gcgr disruption or inducible deletion several weeks before STZ treatment maintained normoglycemia. However, mice with inducible knockout of the Gcgr one week after the onset of STZ diabetes had only partial correction of hyperglycemia, an effect that was reversed by GLP-1 receptor blockade. Mice with Gcgr deletion for either 2 or 6 weeks had similar patterns of gene expression, although the changes were generally larger with longer GCGR knockout. CONCLUSIONS These findings demonstrate that the effects of glucagon to mitigate diabetic hyperglycemia are not through acute signaling but require compensations that take weeks to develop.
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Affiliation(s)
- Belen Rivero-Gutierrez
- Department of Internal Medicine, University of Cincinnati, 2180 E. Galbraith Rd, Cincinnati, OH, USA
| | - April Haller
- Department of Internal Medicine, University of Cincinnati, 2180 E. Galbraith Rd, Cincinnati, OH, USA
| | - Jenna Holland
- Department of Internal Medicine, University of Cincinnati, 2180 E. Galbraith Rd, Cincinnati, OH, USA
| | - Emily Yates
- Department of Internal Medicine, University of Cincinnati, 2180 E. Galbraith Rd, Cincinnati, OH, USA
| | - Radha Khrisna
- Department of Medicine, Duke University School of Medicine, NC, USA
| | - Kirk Habegger
- Comprehensive Diabetes Center and Department of Medicine - Endocrinology, Diabetes & and Metabolism, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Richard Dimarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - David D'Alessio
- Department of Medicine, Duke University School of Medicine, NC, USA
| | - Diego Perez-Tilve
- Department of Internal Medicine, University of Cincinnati, 2180 E. Galbraith Rd, Cincinnati, OH, USA.
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43
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Cigliola V, Ghila L, Thorel F, van Gurp L, Baronnier D, Oropeza D, Gupta S, Miyatsuka T, Kaneto H, Magnuson MA, Osipovich AB, Sander M, Wright CEV, Thomas MK, Furuyama K, Chera S, Herrera PL. Pancreatic islet-autonomous insulin and smoothened-mediated signalling modulate identity changes of glucagon + α-cells. Nat Cell Biol 2018; 20:1267-1277. [PMID: 30361701 PMCID: PMC6215453 DOI: 10.1038/s41556-018-0216-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 09/17/2018] [Indexed: 02/06/2023]
Abstract
The mechanisms that restrict regeneration and maintain cell identity following injury are poorly characterized in higher vertebrates. Following β-cell loss, 1-2% of the glucagon-producing α-cells spontaneously engage in insulin production in mice. Here we explore the mechanisms inhibiting α-cell plasticity. We show that adaptive α-cell identity changes are constrained by intra-islet insulin- and Smoothened-mediated signalling, among others. The combination of β-cell loss or insulin-signalling inhibition, with Smoothened inactivation in α- or δ-cells, stimulates insulin production in more α-cells. These findings suggest that the removal of constitutive 'brake signals' is crucial to neutralize the refractoriness to adaptive cell-fate changes. It appears that the maintenance of cell identity is an active process mediated by repressive signals, which are released by neighbouring cells and curb an intrinsic trend of differentiated cells to change.
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Affiliation(s)
- Valentina Cigliola
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Luiza Ghila
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Department of Clinical Science and KG Jebsen Center for Diabetes Research, University of Bergen, Bergen, Norway
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Léon van Gurp
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Delphine Baronnier
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Daniel Oropeza
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Simone Gupta
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
| | - Takeshi Miyatsuka
- Department of Metabolism and Endocrinology, Graduate School of Medicine , Juntendo University , Tokyo, Japan
| | - Hideaki Kaneto
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Mark A Magnuson
- Departments of Molecular Physiology and Biophysics, Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, USA
| | - Anna B Osipovich
- Departments of Molecular Physiology and Biophysics, Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, USA
| | - Maike Sander
- Department of Pediatrics and Cellular and Molecular Medicine, University of California, San Diego, CA, USA
| | - Christopher E V Wright
- Department of Cell and Developmental Biology, Program in Developmental Biology and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Melissa K Thomas
- Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN, USA
| | - Kenichiro Furuyama
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Simona Chera
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Department of Clinical Science and KG Jebsen Center for Diabetes Research, University of Bergen, Bergen, Norway
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, iGE3 and Centre facultaire du diabète, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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Zhang Y, Thai K, Jin T, Woo M, Gilbert RE. SIRT1 activation attenuates α cell hyperplasia, hyperglucagonaemia and hyperglycaemia in STZ-diabetic mice. Sci Rep 2018; 8:13972. [PMID: 30228292 PMCID: PMC6143559 DOI: 10.1038/s41598-018-32351-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/04/2018] [Indexed: 12/19/2022] Open
Abstract
The NAD+-dependent lysine deacetylase, Sirtuin 1 (SIRT1), plays a central role in metabolic regulation. With type 1 diabetes a disease that is characterised by metabolic dysregulation, we sought to assess the impact of SIRT1 activation in experimental, streptozotocin (STZ)-induced diabetes. CD1 mice with and without STZ-induced diabetes were randomized to receive the SIRT1 activating compound, SRT3025, or vehicle over 20 weeks. Vehicle treated STZ-CD1 mice developed severe hyperglycaemia with near-absent circulating insulin and widespread beta cell loss in association with hyperglucagonaemia and expanded islet alpha cell mass. Without affecting ß-cell mass or circulating insulin, diabetic mice that received SRT3025 had substantially improved glycaemic control with greatly reduced islet α cell mass and lower plasma glucagon concentrations. Consistent with reduced glucagon abundance, the diabetes-associated overexpression of key gluconeogenic enzymes, glucose-6-phosphatase and PEPCK were also lowered by SRT3025. Incubating cultured α cells with SRT3025 diminished their glucagon secretion and proliferative activity in association with a reduction in the α cell associated transcription factor, Aristaless Related Homeobox (Arx). By reducing the paradoxical increase in glucagon, SIRT1 activation may offer a new, α-cell centric approach to the treatment of type 1 diabetes.
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Affiliation(s)
- Yanling Zhang
- St. Michael's Hospital, Keenan Research Centre, Li Ka Shing Knowledge Institute, Toronto, M5B 1W8, Canada
| | - Kerri Thai
- St. Michael's Hospital, Keenan Research Centre, Li Ka Shing Knowledge Institute, Toronto, M5B 1W8, Canada
| | - Tianru Jin
- Toronto General Hospital Research Institute (TGHRI), Toronto, ON, M5G 2C4, Canada
| | - Minna Woo
- Toronto General Hospital Research Institute (TGHRI), Toronto, ON, M5G 2C4, Canada
| | - Richard E Gilbert
- St. Michael's Hospital, Keenan Research Centre, Li Ka Shing Knowledge Institute, Toronto, M5B 1W8, Canada.
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Wu T, Rayner CK, Marathe CS, Jones KL, Horowitz M. Glucagon receptor signalling - backwards and forwards. Expert Opin Investig Drugs 2018; 27:135-138. [PMID: 29333878 DOI: 10.1080/13543784.2018.1428306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Tongzhi Wu
- a School of Medicine , The University of Adelaide , Adelaide , Australia
- b NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
| | - Christopher K Rayner
- a School of Medicine , The University of Adelaide , Adelaide , Australia
- b NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
| | - Chinmay S Marathe
- a School of Medicine , The University of Adelaide , Adelaide , Australia
- b NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
| | - Karen L Jones
- a School of Medicine , The University of Adelaide , Adelaide , Australia
- b NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
| | - Michael Horowitz
- a School of Medicine , The University of Adelaide , Adelaide , Australia
- b NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
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Abstract
Globally, 13% of the world's adult population is obese, and more than 400 million people suffer from diabetes. These conditions are both associated with significant morbidity, mortality and financial cost. Therefore, finding new pharmacological treatments is an imperative. Relative hyperglucagonaemia is seen in all types of diabetes, and has been implicated in its pathogenesis. Consequently, clinical trials are underway using drugs which block glucagon activity to treat type 2 diabetes. Conversely, exogenous glucagon can increase energy expenditure. Therefore, researchers are designing peptides that combine activation of the glucagon receptor with further incretin properties, which will treat obesity while mitigating the hyperglycaemic effects of glucagon. This review will discuss these conflicting physiological properties of glucagon, and the attempts to harness these effects pharmacologically.
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Affiliation(s)
- R V Scott
- Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital, London, W12 0NN, United Kingdom.
| | - S R Bloom
- Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital, London, W12 0NN, United Kingdom.
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Kostic A, King TA, Yang F, Chan K, Yancopoulos GD, Gromada J, Harp JB. A first-in-human pharmacodynamic and pharmacokinetic study of a fully human anti-glucagon receptor monoclonal antibody in normal healthy volunteers. Diabetes Obes Metab 2018; 20:283-291. [PMID: 28755409 PMCID: PMC5813272 DOI: 10.1111/dom.13075] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 07/11/2017] [Accepted: 07/22/2017] [Indexed: 02/06/2023]
Abstract
AIMS Glucagon receptor (GCGR) blockers are being investigated as potential therapeutics for type 1 and type 2 diabetes. Here we report the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of REGN1193, a fully human glucagon receptor blocking monoclonal antibody from a first-in-human healthy volunteer randomized double-blinded trial. METHODS Healthy men and women received single ascending doses of REGN1193 ranging from 0.05 to 0.6 mg/kg (n = 42) or placebo (n = 14) intravenously. Safety, tolerability and PK were assessed over 106 days. The glucose-lowering effect of REGN1193 was assessed after induction of hyperglycaemia by serial glucagon challenges. RESULTS REGN1193 was generally well tolerated. There were small (<3× the upper limit of normal) and transient dose-dependent increases in hepatic aminotransferases. No increase in LDL-C was observed. Hypoglycaemia, assessed as laboratory blood glucose ≤70 mg/dL, occurred in 6/14 (43%) subjects on placebo and 27/42 (57%) on REGN1193 across all dose groups. All episodes of hypoglycaemia were asymptomatic, >50 mg/dL, and did not require treatment or medical assistance. Concentration-time profiles suggest a 2-compartment disposition and marked nonlinearity, consistent with target-mediated clearance. REGN1193 inhibited the glucagon-stimulated glucose increase in a dose-dependent manner. The 0.6 mg/kg dose inhibited the glucagon-induced glucose area under the curve for 0 to 90 minutes (AUC0-90 minutes ) by 80% to 90% on days 3 and 15, while blunting the increase in C-peptide. REGN1193 dose-dependently increased total GLP-1, GLP-2 and glucagon, with plasma levels returning to baseline by day 29 in all dose groups. CONCLUSION REGN1193, a GCGR-blocking monoclonal antibody, produced a safety, tolerability and PK/PD profile suitable for further clinical development. The occurrence of transient elevations in serum hepatic aminotransferases observed here and reported with several small molecule glucagon receptor antagonists suggests an on-target effect of glucagon receptor blockade. The underlying mechanism is unknown.
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MESH Headings
- Adult
- Antibodies, Blocking/administration & dosage
- Antibodies, Blocking/adverse effects
- Antibodies, Blocking/blood
- Antibodies, Blocking/pharmacology
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/adverse effects
- Antibodies, Monoclonal/pharmacokinetics
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal, Humanized
- Biomarkers/blood
- Blood Glucose/analysis
- Cohort Studies
- Dose-Response Relationship, Drug
- Double-Blind Method
- Female
- Follow-Up Studies
- Half-Life
- Humans
- Hypoglycemic Agents/administration & dosage
- Hypoglycemic Agents/adverse effects
- Hypoglycemic Agents/pharmacokinetics
- Hypoglycemic Agents/pharmacology
- Infusions, Intravenous
- Lost to Follow-Up
- Male
- Metabolic Clearance Rate
- Middle Aged
- Patient Dropouts
- Receptors, Glucagon/antagonists & inhibitors
- Receptors, Glucagon/metabolism
- Young Adult
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Affiliation(s)
- Ana Kostic
- Regeneron Pharmaceuticals, Inc.TarrytownNew York
| | | | - Feng Yang
- Regeneron Pharmaceuticals, Inc.TarrytownNew York
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48
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Hayashi Y, Seino Y. Regulation of amino acid metabolism and α-cell proliferation by glucagon. J Diabetes Investig 2018; 9:464-472. [PMID: 29314731 PMCID: PMC5934249 DOI: 10.1111/jdi.12797] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 12/21/2017] [Indexed: 12/25/2022] Open
Abstract
Both glucagon and glucagon-like peptide-1 (GLP-1) are produced from proglucagon through proteolytic cleavage. Blocking glucagon action increases the circulating levels of glucagon and GLP-1, reduces the blood glucose level, and induces the proliferation of islet α-cells. Glucagon blockade also suppresses hepatic amino acid catabolism and increases the serum amino acid level. In animal models defective in both glucagon and GLP-1, the blood glucose level is not reduced, indicating that GLP-1 is required for glucagon blockade to reduce the blood glucose level. In contrast, hyperplasia of α-cells and hyperaminoacidemia are observed in such animal models, indicating that GLP-1 is not required for the regulation of α-cell proliferation or amino acid metabolism. These findings suggest that the regulation of amino acid metabolism is a more important specific physiological role of glucagon than the regulation of glucose metabolism. Although the effects of glucagon deficiency on glucose metabolism are compensated by the suppression of insulin secretion, the effects on amino acid metabolism are not. Recently, data showing a feedback regulatory mechanism between the liver and islet α-cells, which is mediated by glucagon and amino acids, are accumulating. However, a number of questions on the mechanism of this regulation remain to be addressed. The profile of glucagon as a regulator of amino acid metabolism must be carefully considered for glucagon blockade to be applied therapeutically in the treatment of patients with diabetes.
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Affiliation(s)
- Yoshitaka Hayashi
- Division of Stress Adaptation and ProtectionResearch Institute of Environmental MedicineNagoyaJapan
| | - Yusuke Seino
- Department of Endocrinology and DiabetesNagoya University Graduate School of MedicineNagoya UniversityNagoyaJapan
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Grøndahl MF, Keating DJ, Vilsbøll T, Knop FK. Current Therapies That Modify Glucagon Secretion: What Is the Therapeutic Effect of Such Modifications? Curr Diab Rep 2017; 17:128. [PMID: 29080075 DOI: 10.1007/s11892-017-0967-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Hyperglucagonemia contributes significantly to hyperglycemia in type 2 diabetes and suppressed glucagon levels may increase the risk of hypoglycemia. Here, we give a brief overview of glucagon physiology and the role of glucagon in the pathophysiology of type 2 diabetes and provide insights into how antidiabetic drugs influence glucagon secretion as well as a perspective on the future of glucagon-targeting drugs. RECENT FINDINGS Several older as well as recent investigations have evaluated the effect of antidiabetic agents on glucagon secretion to understand how glucagon may be involved in the drugs' efficacy and safety profiles. Based on these findings, modulation of glucagon secretion seems to play a hitherto underestimated role in the efficacy and safety of several glucose-lowering drugs. Numerous drugs currently available to diabetologists are capable of altering glucagon secretion: metformin, sulfonylurea compounds, insulin, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, sodium-glucose cotransporter 2 inhibitors and amylin mimetics. Their diverse effects on glucagon secretion are of importance for their individual efficacy and safety profiles. Understanding how these drugs interact with glucagon secretion may help to optimize treatment.
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Affiliation(s)
- Magnus F Grøndahl
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Damien J Keating
- Discipline of Human Physiology and Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
| | - Tina Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, University of Copenhagen, Gentofte, Denmark
| | - Filip K Knop
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
- Department of Clinical Medicine, Faculty of Health and Medical sciences, University of Copenhagen, Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Metabolic Research, Faculty of Health and Medical sciences, University of Copenhagen, Copenhagen, Denmark.
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50
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Scheen AJ, Paquot N, Lefèbvre PJ. Investigational glucagon receptor antagonists in Phase I and II clinical trials for diabetes. Expert Opin Investig Drugs 2017; 26:1373-1389. [PMID: 29052441 DOI: 10.1080/13543784.2017.1395020] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Despite type 2 diabetes (T2D) being recognized as a bihormonal pancreatic disease, current therapies are mainly focusing on insulin, while targeting glucagon has been long dismissed. However, glucagon receptor (GCGr) antagonists are currently investigated in clinical trials. Area covered: Following a brief description of the rationale for antagonizing GCGr in T2D, lessons from GCGr knock-out mice and pharmacological means to antagonize GCGr, a detailed description of the main results obtained with GCGr antagonists in Phase I-II clinical trials is provided. The development of several small molecules has been discontinued, while new ones are currently considered as well as innovative approaches such as monoclonal antibodies or antisense oligonucleotides inhibiting GCGr gene expression. Their potential benefits but also limitations are discussed. Expert opinion: The proof-of-concept that antagonizing GCGr improves glucose control in T2D has been confirmed in humans. Nevertheless, some adverse events led to stopping the development of some of these GCGr antagonists. New approaches seem to have a better benefit/risk balance, although none has progressed to Phase III clinical trials so far. Pharmacotherapy of T2D is becoming a highly competitive field so that GCGr antagonists should provide clear advantages over numerous existing glucose-lowering medications before eventually reaching clinical practice.
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Affiliation(s)
- André J Scheen
- a Division of Clinical Pharmacology , Center for Interdisciplinary Research on Medicines (CIRM), University of Liège , Belgium.,b Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine , CHU , Liège , Belgium
| | - Nicolas Paquot
- b Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine , CHU , Liège , Belgium
| | - Pierre J Lefèbvre
- b Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine , CHU , Liège , Belgium
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