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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; 6:1791-1806. [PMID: 39169271 PMCID: PMC11422169 DOI: 10.1038/s42255-024-01114-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 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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Zhang L, Qin Y, Huang Y, Hu Q, Wu Q, Wang X, Zhang M. Abnormal late postprandial glucagon response in type 1 diabetes is a function of differences in stimulated C-peptide concentrations. Front Endocrinol (Lausanne) 2024; 15:1419329. [PMID: 39149119 PMCID: PMC11324558 DOI: 10.3389/fendo.2024.1419329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Accepted: 07/17/2024] [Indexed: 08/17/2024] Open
Abstract
Background The functional changes in alpha cells in patients with type 1 diabetes (T1D) with different residual beta cell functions remain poorly elucidated. The study aimed to investigate the relationship between glucagon secretion and C-peptide levels and to explore the relationship between glucagon response and glucose increment in respond to a secretagogue in a steamed bread meal tolerance test (BMTT) in T1D. Methods The study enrolled 43 adult patients with T1D and 24 healthy control subjects. Patients with T1D who underwent BMTT were divided into two groups based on peak C-peptide levels: C peptide low (CPL; C-peptide < 200 pmol/L; n=14) and high (CPH; C peptide ≥ 200 pmol/L; n=29). Plasma glucose, C-peptide, glucagon levels at 0, 30, 60, 120, and 180 min were measured. The glucagon response to the BMTT was defined by areas under the curve (AUC) as early (AUC0-30), late (AUC30-180), or total (AUC0-180) glucagon. Results Compared to healthy individuals, fasting plasma glucagon was lower and postprandial plasma glucagon level was increased in patients with T1D. Glucagon levels after BMTT between the CPL and CPH group showed significant group by time interaction. Peak glucagon and glucagon at 60-180 min, total and late glucagon response were higher in CPL than CPH group, while fasting glucagon and early glucagon response adjusted for glucose were comparable between CPL and CPH group. The higher late glucagon response and late glucagon response adjusted for glucose were associated with lower peak C-peptide in T1D. The higher late glucagon response and lower peak C-peptide were associated with the higher value of ▵glucose at 180 min. Conclusion Stimulated C-peptide levels affect the paradoxical increase in postprandial glucagon secretion in patients with T1D, especially late glucagon response. The exaggerated postprandial glucagon secretion further stimulates the elevation of postprandial glucose in patients with T1D.
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Affiliation(s)
- Lingyu Zhang
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Endocrinology, The Affiliated Changzhou Second People’s Hospital of Nanjing Medical University, Nanjing Medical University, Changzhou, Jiangsu, China
| | - Yao Qin
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yiting Huang
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qizhen Hu
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qian Wu
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xing Wang
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Mei Zhang
- Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China
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3
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Wang M, Fu X, Du L, Shi F, Huang Z, Yang L. The Inferential Binding Sites of GCGR for Small Molecules Using Protein Dynamic Conformations and Crystal Structures. Int J Mol Sci 2024; 25:8389. [PMID: 39125959 PMCID: PMC11313378 DOI: 10.3390/ijms25158389] [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: 05/29/2024] [Revised: 07/23/2024] [Accepted: 07/25/2024] [Indexed: 08/12/2024] Open
Abstract
Glucagon receptor (GCGR) is a class B1 G-protein-coupled receptor that plays a crucial role in maintaining human blood glucose homeostasis and is a significant target for the treatment of type 2 diabetes mellitus (T2DM). Currently, six small molecules (Bay 27-9955, MK-0893, MK-3577, LY2409021, PF-06291874, and LGD-6972) have been tested or are undergoing clinical trials, but only the binding site of MK-0893 has been resolved. To predict binding sites for other small molecules, we utilized both the crystal structure of the GCGR and MK-0893 complex and dynamic conformations. We docked five small molecules and selected the best conformation based on binding mode, docking score, and binding free energy. We performed MD simulations to verify the binding mode of the selected small molecules. Moreover, when selecting conformations, results of competitive binding were referred to. MD simulation indicated that Bay 27-9955 exhibits moderate binding stability in Pocket 3. MK-3577, LY2409021, and PF-06291874 exhibited highly stable binding to Pocket 2, consistent with experimental results. However, LY2409021 may also bind to Pocket 5. Additionally, LGD-6972 exhibited relatively stable binding in Pocket 5. We also conducted structural modifications of LGD-6972 based on the results of MD simulations and predicted its analogues' bioavailability, providing a reference for the study of GCGR small molecules.
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Affiliation(s)
- Mengru Wang
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China; (M.W.); (X.F.); (L.D.); (F.S.)
| | - Xulei Fu
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China; (M.W.); (X.F.); (L.D.); (F.S.)
| | - Limin Du
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China; (M.W.); (X.F.); (L.D.); (F.S.)
| | - Fan Shi
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China; (M.W.); (X.F.); (L.D.); (F.S.)
| | - Zichong Huang
- Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China;
| | - Linlin Yang
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou 450001, China; (M.W.); (X.F.); (L.D.); (F.S.)
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4
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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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5
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Guo W, Gao L, Mo H, Deng H, Zhao Y, Xu G. Mechano-sensor Piezo1 inhibits glucagon production in pancreatic α-cells. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167185. [PMID: 38653360 DOI: 10.1016/j.bbadis.2024.167185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 04/25/2024]
Abstract
OBJECTIVE Glucagon is a critical hormone regulating glucose metabolism. It stimulates the liver to release glucose under low blood sugar conditions, thereby maintaining blood glucose stability. Excessive glucagon secretion and hyperglycemia is observed in individuals with diabetes. Precise modulation of glucagon is significant to maintain glucose homeostasis. Piezo1 is a mechanosensitive ion channel capable of converting extracellular mechanical forces into intracellular signals, thus regulating hormonal synthesis and secretion. This study aims to investigate the role of Piezo1 in regulating glucagon production in α cells. METHODS The effects of Piezo1 on glucagon production were examined in normal- or high-fat diet fed α cell-specific Piezo1 knockout mice (Gcg-Piezo1-/-), and the murine pancreatic α cell line αTC1-6. Expression of Proglucagon was investigated by real-time PCR and western blotting. Plasma glucagon and insulin were detected by enzyme immunoassay. RESULTS Under both normal- and high-fat diet conditions, Gcg-Piezo1-/- mice exhibited increased pancreatic α cell proportion, hyperglucagonemia, impaired glucose tolerance, and activated pancreatic mTORC1 signaling. Activation of Piezo1 by its agonist Yoda1 or overexpression of Piezo1 led to decreased glucagon synthesis and suppressed mTOR signaling pathway in αTC1-6 cells. Additionally, the levels of glucagon in the medium were also reduced. Conversely, knockdown of Piezo1 produced opposite effects. CONCLUSION Our study uncovers the regulatory role of the Piezo1 ion channel in α cells. Piezo1 influences glucagon production by affecting mTOR signaling pathway.
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Affiliation(s)
- Wenying Guo
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Luyang Gao
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Haocong Mo
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Handan Deng
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Yawen Zhao
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Geyang Xu
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China; Key Laboratory of Viral Pathogenesis & Infection Prevention and Control (Jinan University), Ministry of Education, Guangzhou 510632, Guangdong, China.
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6
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Estes SK, Shiota C, O'Brien TP, Printz RL, Shiota M. The impact of glucagon to support postabsorptive glucose flux and glycemia in healthy rats and its attenuation in male Zucker diabetic fatty rats. Am J Physiol Endocrinol Metab 2024; 326:E308-E325. [PMID: 38265288 PMCID: PMC11193518 DOI: 10.1152/ajpendo.00192.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 01/19/2024] [Accepted: 01/19/2024] [Indexed: 01/25/2024]
Abstract
Hyperglucagonemia is a hallmark of type 2 diabetes (T2DM), yet the role of elevated plasma glucagon (P-GCG) to promote excessive postabsorptive glucose production and contribute to hyperglycemia in patients with this disease remains debatable. We investigated the acute action of P-GCG to safeguard/support postabsorptive endogenous glucose production (EGP) and euglycemia in healthy Zucker control lean (ZCL) rats. Using male Zucker diabetic fatty (ZDF) rats that exhibit the typical metabolic disorders of human T2DM, such as excessive EGP, hyperglycemia, hyperinsulinemia, and hyperglucagonemia, we examined the ability of hyperglucagonemia to promote greater rates of postabsorptive EGP and hyperglycemia. Euglycemic or hyperglycemic basal insulin (INS-BC) and glucagon (GCG-BC) clamps were performed in the absence or during an acute setting of glucagon deficiency (GCG-DF, ∼10% of basal), either alone or in combination with insulin deficiency (INS-DF, ∼10% of basal). Glucose appearance, disappearance, and cycling rates were measured using [2-3H] and [3-3H]-glucose. In ZCL rats, GCG-DF reduced the levels of hepatic cyclic AMP, EGP, and plasma glucose (PG) by 50%, 32%, and 50%, respectively. EGP fell in the presence GCG-DF and INS-BC, but under GCG-DF and INS-DF, EGP and PG increased two- and threefold, respectively. GCG-DF revealed the hyperglucagonemia present in ZDF rats lacked the ability to regulate hepatic intracellular cyclic AMP levels and glucose flux, since EGP and PG levels fell by only 10%. We conclude that the liver in T2DM suffers from resistance to all three major regulatory factors, glucagon, insulin, and glucose, thus leading to a loss of metabolic flexibility.NEW & NOTEWORTHY In postabsorptive state, basal plasma insulin (P-INS) and plasma glucose (PG) act dominantly to increase hepatic glucose cycling and reduce endogenous glucose production (EGP) and PG in healthy rats, which is only counteracted by the acute action of basal plasma glucagon (P-GCG) to support EGP and euglycemia. Hyperglucagonemia, a hallmark of type 2 diabetes (T2DM) present in Zucker diabetic fatty (ZDF) rats, is not the primary mediator of hyperglycemia and high EGP as commonly thought; instead, the liver is resistant to glucagon as well as insulin and glucose.
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Affiliation(s)
- Shanea K Estes
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Chiyo Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Tracy P O'Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Richard L Printz
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Masakazu Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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Asadi F, Gunawardana SC, Dolle RE, Piston DW. An orally available compound suppresses glucagon hypersecretion and normalizes hyperglycemia in type 1 diabetes. JCI Insight 2024; 9:e172626. [PMID: 38258903 PMCID: PMC10906223 DOI: 10.1172/jci.insight.172626] [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: 05/31/2023] [Accepted: 12/05/2023] [Indexed: 01/24/2024] Open
Abstract
Suppression of glucagon hypersecretion can normalize hyperglycemia during type 1 diabetes (T1D). Activating erythropoietin-producing human hepatocellular receptor type-A4 (EphA4) on α cells reduced glucagon hypersecretion from dispersed α cells and T1D islets from both human donor and mouse models. We synthesized a high-affinity small molecule agonist for the EphA4 receptor, WCDD301, which showed robust plasma and liver microsome metabolic stability in both mouse and human preparations. In islets and dispersed islet cells from nondiabetic and T1D human donors, WCDD301 reduced glucagon secretion comparable to the natural EphA4 ligand, Ephrin-A5. In diabetic NOD and streptozotocin-treated mice, once-daily oral administration of WCDD301 formulated with a time-release excipient reduced plasma glucagon and normalized blood glucose for more than 3 months. These results suggest that targeting the α cell EphA4 receptor by sustained release of WCDD301 is a promising pharmacologic pathway for normalizing hyperglycemia in patients with T1D.
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Affiliation(s)
| | | | - Roland E. Dolle
- Center for Drug Discovery, Washington University School of Medicine, St. Louis, Missouri, USA
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8
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Riahi Y, Kogot-Levin A, Kadosh L, Agranovich B, Malka A, Assa M, Piran R, Avrahami D, Glaser B, Gottlieb E, Jackson F, Cerasi E, Bernal-Mizrachi E, Helman A, Leibowitz G. Hyperglucagonaemia in diabetes: altered amino acid metabolism triggers mTORC1 activation, which drives glucagon production. Diabetologia 2023; 66:1925-1942. [PMID: 37480416 DOI: 10.1007/s00125-023-05967-8] [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: 02/22/2023] [Accepted: 06/07/2023] [Indexed: 07/24/2023]
Abstract
AIM/HYPOTHESIS Hyperglycaemia is associated with alpha cell dysfunction, leading to dysregulated glucagon secretion in type 1 and type 2 diabetes; however, the mechanisms involved are still elusive. The nutrient sensor mammalian target of rapamycin complex 1 (mTORC1) plays a major role in the maintenance of alpha cell mass and function. We studied the regulation of alpha cell mTORC1 by nutrients and its role in the development of hyperglucagonaemia in diabetes. METHODS Alpha cell mTORC1 activity was assessed by immunostaining for phosphorylation of its downstream target, the ribosomal protein S6, and glucagon, followed by confocal microscopy on pancreatic sections and flow cytometry on dispersed human and mouse islets and the alpha cell line, αTC1-6. Metabolomics and metabolic flux were studied by 13C glucose labelling in 2.8 or 16.7 mmol/l glucose followed by LC-MS analysis. To study the role of mTORC1 in mediating hyperglucagonaemia in diabetes, we generated an inducible alpha cell-specific Rptor knockout in the Akita mouse model of diabetes and tested the effects on glucose tolerance by IPGTT and on glucagon secretion. RESULTS mTORC1 activity was increased in alpha cells from diabetic Akita mice in parallel to the development of hyperglycaemia and hyperglucagonaemia (two- to eightfold increase). Acute exposure of mouse and human islets to amino acids stimulated alpha cell mTORC1 (3.5-fold increase), whereas high glucose concentrations inhibited mTORC1 (1.4-fold decrease). The mTORC1 response to glucose was abolished in human and mouse diabetic alpha cells following prolonged islet exposure to high glucose levels, resulting in sustained activation of mTORC1, along with increased glucagon secretion. Metabolomics and metabolic flux analysis showed that exposure to high glucose levels enhanced glycolysis, glucose oxidation and the synthesis of glucose-derived amino acids. In addition, chronic exposure to high glucose levels increased the expression of Slc7a2 and Slc38a4, which encode amino acid transporters, as well as the levels of branched-chain amino acids and methionine cycle metabolites (~1.3-fold increase for both). Finally, conditional Rptor knockout in alpha cells from adult diabetic mice inhibited mTORC1, thereby inhibiting glucagon secretion (~sixfold decrease) and improving diabetes, despite persistent insulin deficiency. CONCLUSIONS/INTERPRETATION Alpha cell exposure to hyperglycaemia enhances amino acid synthesis and transport, resulting in sustained activation of mTORC1, thereby increasing glucagon secretion. mTORC1 therefore plays a major role in mediating alpha cell dysfunction in diabetes. DATA AVAILABILITY All sequencing data are available from the Gene Expression Omnibus (GEO) repository (accession no. GSE154126; https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE154126 ).
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Affiliation(s)
- Yael Riahi
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aviram Kogot-Levin
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Liat Kadosh
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bella Agranovich
- Laboratory for Metabolism in Health and Disease, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Assaf Malka
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Michael Assa
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ron Piran
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Dana Avrahami
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Developmental Biology and Cancer Research, Hadassah Medical Center, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Glaser
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Eyal Gottlieb
- Laboratory for Metabolism in Health and Disease, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Fields Jackson
- Department of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Erol Cerasi
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Aharon Helman
- Department of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel.
| | - Gil Leibowitz
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
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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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Ajmal N, Bogart MC, Khan P, Max-Harry IM, Nunemaker CS. Emerging Anti-Diabetic Drugs for Beta-Cell Protection in Type 1 Diabetes. Cells 2023; 12:1472. [PMID: 37296593 PMCID: PMC10253164 DOI: 10.3390/cells12111472] [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: 04/10/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Type 1 diabetes (T1D) is a chronic autoimmune disorder that damages beta cells in the pancreatic islets of Langerhans and results in hyperglycemia due to the loss of insulin. Exogenous insulin therapy can save lives but does not halt disease progression. Thus, an effective therapy may require beta-cell restoration and suppression of the autoimmune response. However, currently, there are no treatment options available that can halt T1D. Within the National Clinical Trial (NCT) database, a vast majority of over 3000 trials to treat T1D are devoted to insulin therapy. This review focuses on non-insulin pharmacological therapies. Many investigational new drugs fall under the category of immunomodulators, such as the recently FDA-approved CD-3 monoclonal antibody teplizumab. Four intriguing candidate drugs fall outside the category of immunomodulators, which are the focus of this review. Specifically, we discuss several non-immunomodulators that may have more direct action on beta cells, such as verapamil (a voltage-dependent calcium channel blocker), gamma aminobutyric acid (GABA, a major neurotransmitter with effects on beta cells), tauroursodeoxycholic acid (TUDCA, an endoplasmic reticulum chaperone), and volagidemab (a glucagon receptor antagonist). These emerging anti-diabetic drugs are expected to provide promising results in both beta-cell restoration and in suppressing cytokine-derived inflammation.
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Affiliation(s)
- Nida Ajmal
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (N.A.); (P.K.); (I.M.M.-H.)
- Translational Biomedical Sciences Graduate Program, Ohio University, Athens, OH 45701, USA
| | | | - Palwasha Khan
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (N.A.); (P.K.); (I.M.M.-H.)
- Translational Biomedical Sciences Graduate Program, Ohio University, Athens, OH 45701, USA
| | - Ibiagbani M. Max-Harry
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (N.A.); (P.K.); (I.M.M.-H.)
- Molecular and Cellular Biology Graduate Program, Ohio University, Athens, OH 45701, USA
| | - Craig S. Nunemaker
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA; (N.A.); (P.K.); (I.M.M.-H.)
- Translational Biomedical Sciences Graduate Program, Ohio University, Athens, OH 45701, USA
- Molecular and Cellular Biology Graduate Program, Ohio University, Athens, OH 45701, USA
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11
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Lutz TA. Mammalian models of diabetes mellitus, with a focus on type 2 diabetes mellitus. Nat Rev Endocrinol 2023; 19:350-360. [PMID: 36941447 DOI: 10.1038/s41574-023-00818-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/21/2023] [Indexed: 03/23/2023]
Abstract
Although no single animal model replicates all aspects of diabetes mellitus in humans, animal models are essential for the study of energy balance and metabolism control as well as to investigate the reasons for their imbalance that could eventually lead to overt metabolic diseases such as type 2 diabetes mellitus. The most frequently used animal models in diabetes mellitus research are small rodents that harbour spontaneous genetic mutations or that can be manipulated genetically or by other means to influence their nutrient metabolism and nutrient handling. Non-rodent species, including pigs, cats and dogs, are also useful models in diabetes mellitus research. This Review will outline the advantages and disadvantages of selected animal models of diabetes mellitus to build a basis for their most appropriate use in biomedical research.
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Affiliation(s)
- Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
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12
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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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13
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Kalwat MA, Rodrigues-dos-Santos K, Binns DD, Wei S, Zhou A, Evans MR, Posner BA, Roth MG, Cobb MH. Small molecule glucagon release inhibitors with activity in human islets. Front Endocrinol (Lausanne) 2023; 14:1114799. [PMID: 37152965 PMCID: PMC10157210 DOI: 10.3389/fendo.2023.1114799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 04/07/2023] [Indexed: 05/09/2023] Open
Abstract
Purpose Type 1 diabetes (T1D) accounts for an estimated 5% of all diabetes in the United States, afflicting over 1.25 million individuals. Maintaining long-term blood glucose control is the major goal for individuals with T1D. In T1D, insulin-secreting pancreatic islet β-cells are destroyed by the immune system, but glucagon-secreting islet α-cells survive. These remaining α-cells no longer respond properly to fluctuating blood glucose concentrations. Dysregulated α-cell function contributes to hyper- and hypoglycemia which can lead to macrovascular and microvascular complications. To this end, we sought to discover small molecules that suppress α-cell function for their potential as preclinical candidate compounds. Prior high-throughput screening identified a set of glucagon-suppressing compounds using a rodent α-cell line model, but these compounds were not validated in human systems. Results Here, we dissociated and replated primary human islet cells and exposed them to 24 h treatment with this set of candidate glucagon-suppressing compounds. Glucagon accumulation in the medium was measured and we determined that compounds SW049164 and SW088799 exhibited significant activity. Candidate compounds were also counter-screened in our InsGLuc-MIN6 β-cell insulin secretion reporter assay. SW049164 and SW088799 had minimal impact on insulin release after a 24 h exposure. To further validate these hits, we treated intact human islets with a selection of the top candidates for 24 h. SW049164 and SW088799 significantly inhibited glucagon release into the medium without significantly altering whole islet glucagon or insulin content. In concentration-response curves SW088799 exhibited significant inhibition of glucagon release with an IC50 of 1.26 µM. Conclusion Given the set of tested candidates were all top hits from the primary screen in rodent α-cells, this suggests some conservation of mechanism of action between human and rodents, at least for SW088799. Future structure-activity relationship studies of SW088799 may aid in elucidating its protein target(s) or enable its use as a tool compound to suppress α-cell activity in vitro.
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Affiliation(s)
- Michael A. Kalwat
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN, United States
- Indiana University School of Medicine, Center for Diabetes and Metabolic Diseases, Indianapolis, IN, United States
- *Correspondence: Michael A. Kalwat, ;
| | - Karina Rodrigues-dos-Santos
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN, United States
| | - Derk D. Binns
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Shuguang Wei
- Department Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Anwu Zhou
- Department Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Matthew R. Evans
- Department Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Bruce A. Posner
- Department Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Michael G. Roth
- Department Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Melanie H. Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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14
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Asadi F, Dhanvantari S. Misrouting of glucagon and stathmin-2 towards lysosomal system of α-cells in glucagon hypersecretion of diabetes. Islets 2022; 14:40-57. [PMID: 34923907 PMCID: PMC8726656 DOI: 10.1080/19382014.2021.2011550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Glucagon hypersecretion from the pancreatic α-cell is a characteristic sign of diabetes, which exacerbates fasting hyperglycemia. Thus, targeting glucagon secretion from α-cells may be a promising approach for combating hyperglucagonemia. We have recently identified stathmin-2 as an α-cell protein that regulates glucagon secretion by directing glucagon toward the endolysosomal system in αTC1-6 cells. We hypothesized that disruption of Stmn2-mediated trafficking of glucagon to the endolysosomes in diabetes contributes to hyperglucagonemia. In isolated islets from male mice treated with streptozotocin (STZ), glucagon secretion and cellular content were augmented, but cellular Stmn2 levels were reduced (p < .01), as measured by both ELISA and immunofluorescence intensity. Using confocal immunofluorescence microscopy, the colocalization of glucagon and Stmn2 in Lamp2A+ lysosomes was dramatically reduced (p < .001) in islets from diabetic mice, and the colocalization of Stmn2, but not glucagon, with the late endosome marker, Rab7, significantly (p < .01) increased. Further studies were conducted in αTC1-6 cells cultured in media containing high glucose (16.7 mM) for 2 weeks to mimic glucagon hypersecretion of diabetes. Surprisingly, treatment of αTC1-6 cells with the lysosomal inhibitor bafilomycin A1 reduced K+-induced glucagon secretion, suggesting that high glucose may induce glucagon secretion from another lysosomal compartment. Both glucagon and Stmn2 co-localized with Lamp1, which marks secretory lysosomes, in cells cultured in high glucose. We propose that, in addition to enhanced trafficking and secretion through the regulated secretory pathway, the hyperglucagonemia of diabetes may also be due to re-routing of glucagon from the degradative Lamp2A+ lysosome toward the secretory Lamp1+ lysosome.
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Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Western University, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
- Metabolism & Diabetes and Imaging Programs, Lawson Health Research Institute, London, ON, Canada
- CONTACT Savita Dhanvantari Lawson Health Research Institute, PO Box 5777, Stn B, London, ONN6A 4V2, Canada
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15
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A randomized trial of oral gamma aminobutyric acid (GABA) or the combination of GABA with glutamic acid decarboxylase (GAD) on pancreatic islet endocrine function in children with newly diagnosed type 1 diabetes. Nat Commun 2022; 13:7928. [PMID: 36566274 PMCID: PMC9790014 DOI: 10.1038/s41467-022-35544-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/06/2022] [Indexed: 12/25/2022] Open
Abstract
Gamma aminobutyric acid(GABA) is synthesized by glutamate decarboxylase(GAD) in β-cells. Regarding Type 1 diabetes(T1D), animal/islet-cell studies found that GABA promotes insulin secretion, inhibits α-cell glucagon and dampens immune inflammation, while GAD immunization may also preserve β-cells. We evaluated the safety and efficacy of oral GABA alone, or combination GABA with GAD, on the preservation of residual insulin secretion in recent-onset T1D. Herein we report a single-center, double-blind, one-year, randomized trial in 97 children conducted March 2015 to June 2019(NCT02002130). Using a 2:1 treatment:placebo ratio, interventions included oral GABA twice-daily(n = 41), or oral GABA plus two-doses GAD-alum(n = 25), versus placebo(n = 31). The primary outcome, preservation of fasting/meal-stimulated c-peptide, was not attained. Of the secondary outcomes, the combination GABA/GAD reduced fasting and meal-stimulated serum glucagon, while the safety/tolerability of GABA was confirmed. There were no clinically significant differences in glycemic control or diabetes antibody titers. Given the low GABA dose for this pediatric trial, future investigations using higher-dose or long-acting GABA formulations, either alone or with GAD-alum, could be considered, although GABA alone or in combination with GAD-alum did nor preserve beta-cell function in this trial.
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16
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Kang Q, Zheng J, Jia J, Xu Y, Bai X, Chen X, Zhang XK, Wong FS, Zhang C, Li M. Disruption of the glucagon receptor increases glucagon expression beyond α-cell hyperplasia in zebrafish. J Biol Chem 2022; 298:102665. [PMID: 36334626 PMCID: PMC9719020 DOI: 10.1016/j.jbc.2022.102665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
The glucagon receptor (GCGR) is a potential target for diabetes therapy. Several emerging GCGR antagonism-based therapies are under preclinical and clinical development. However, GCGR antagonism, as well as genetically engineered GCGR deficiency in animal models, are accompanied by α-cell hyperplasia and hyperglucagonemia, which may limit the application of GCGR antagonism. To better understand the physiological changes in α cells following GCGR disruption, we performed single cell sequencing of α cells isolated from control and gcgr-/- (glucagon receptor deficient) zebrafish. Interestingly, beyond the α-cell hyperplasia, we also found that the expression of gcga, gcgb, pnoca, and several glucagon-regulatory transcription factors were dramatically increased in one cluster of gcgr-/- α cells. We further confirmed that glucagon mRNA was upregulated in gcgr-/- animals by in situ hybridization and that glucagon promoter activity was increased in gcgr-/-;Tg(gcga:GFP) reporter zebrafish. We also demonstrated that gcgr-/- α cells had increased glucagon protein levels and increased granules after GCGR disruption. Intriguingly, the increased mRNA and protein levels could be suppressed by treatment with high-level glucose or knockdown of the pnoca gene. In conclusion, these data demonstrated that GCGR deficiency not only induced α-cell hyperplasia but also increased glucagon expression in α cells, findings which provide more information about physiological changes in α-cells when the GCGR is disrupted.
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Affiliation(s)
- Qi Kang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Jihong Zheng
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jianxin Jia
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Ying Xu
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xuanxuan Bai
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xinhua Chen
- Key Laboratory of Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiao-Kun Zhang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - F Susan Wong
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, UK
| | - Chao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Mingyu Li
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, 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: 31] [Impact Index Per Article: 15.5] [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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Affiliation(s)
- Maria F Rubin de Celis
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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19
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Pettus J, Boeder SC, Christiansen MP, Denham DS, Bailey TS, Akturk HK, Klaff LJ, Rosenstock J, Cheng MHM, Bode BW, Bautista ED, Xu R, Yan H, Thai D, Garg SK, Klein S. Glucagon receptor antagonist volagidemab in type 1 diabetes: a 12-week, randomized, double-blind, phase 2 trial. Nat Med 2022; 28:2092-2099. [PMID: 36192552 PMCID: PMC9872851 DOI: 10.1038/s41591-022-02011-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 08/15/2022] [Indexed: 01/26/2023]
Abstract
Hyperglucagonemia contributes to hyperglycemia in patients with type 1 diabetes (T1D); however, novel therapeutics that block glucagon action could improve glycemic control. This phase 2 study evaluated the safety and efficacy of volagidemab, an antagonistic monoclonal glucagon receptor (GCGR) antibody, as an adjunct to insulin therapy in adults with T1D. The primary endpoint was change in daily insulin use at week 12. Secondary endpoints included changes in hemoglobin A1c (HbA1c) at week 13, in average daily blood glucose concentration and time within target range as assessed by continuous blood glucose monitoring (CGM) and seven-point glucose profile at week 12, incidence of hypoglycemic events, the proportion of subjects who achieve HbA1c reduction of ≥0.4%, volagidemab drug concentrations and incidence of anti-drug antibodies. Eligible participants (n = 79) were randomized to receive weekly subcutaneous injections of placebo, 35 mg volagidemab or 70 mg volagidemab. Volagidemab produced a reduction in total daily insulin use at week 12 (35 mg volagidemab: -7.59 units (U) (95% confidence interval (CI) -11.79, -3.39; P = 0.040 versus placebo); 70 mg volagidemab: -6.64 U (95% CI -10.99, -2.29; P = 0.084 versus placebo); placebo: -1.27 U (95% CI -5.4, 2.9)) without meeting the prespecified significance level (P < 0.025). At week 13, the placebo-corrected reduction in HbA1c percentage was -0.53 (95% CI -0.89 to -0.17, nominal P = 0.004) in the 35 mg volagidemab group and -0.49 (95% CI -0.85 to -0.12, nominal P = 0.010) in the 70 mg volagidemab group. No increase in hypoglycemia was observed with volagidemab therapy; however, increases in serum transaminases, low-density lipoprotein (LDL)-cholesterol and blood pressure were observed. Although the primary endpoint did not meet the prespecified significance level, we believe that the observed reduction in HbA1c and tolerable safety profile provide a rationale for further randomized studies to define the long-term efficacy and safety of volagidemab in patients with T1D.
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Affiliation(s)
- Jeremy Pettus
- Division of Endocrinology, University of California San Diego, La Jolla, CA, USA.
| | - Schafer C Boeder
- Division of Endocrinology, University of California San Diego, La Jolla, CA, USA
| | | | | | | | - Halis K Akturk
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Campus, Aurora, CO, USA
| | | | | | | | | | | | - Ren Xu
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Dung Thai
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Satish K Garg
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Campus, Aurora, CO, USA
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO and Sansum Diabetes Research Institute, Santa Barbara, CA, USA
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20
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Perry RJ. Regulation of Hepatic Lipid and Glucose Metabolism by INSP3R1. Diabetes 2022; 71:1834-1841. [PMID: 35657697 PMCID: PMC9450566 DOI: 10.2337/dbi22-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/13/2022] [Indexed: 11/13/2022]
Abstract
With the rising epidemics of obesity and nonalcoholic fatty liver disease (NAFLD) and its downstream consequences including steatohepatitis, cirrhosis, and type 2 diabetes in the U.S. and worldwide, new therapeutic approaches are urgently needed to treat these devastating conditions. Glucagon, known for a century to be a glucose-raising hormone and clearly demonstrated to contribute to fasting and postprandial hyperglycemia in both type 1 and type 2 diabetes, represents an unlikely target to improve health in those with metabolic syndrome. However, recent work from our group and others' identifies an unexpected role for glucagon as a potential means of treating NAFLD, improving insulin sensitivity, and improving the lipid profile. We propose a unifying, calcium-dependent mechanism for glucagon's effects both to stimulate hepatic gluconeogenesis and to enhance hepatic mitochondrial oxidation: signaling through the inositol 1,4,5-trisphosphate receptor type 1 (INSP3R1), glucagon activates phospholipase C (PKC)/protein kinase A (PKA) signaling to enhance adipose triglyceride lipase (ATGL)-dependent intrahepatic lipolysis and, in turn, increase cytosolic gluconeogenesis by allosteric activation of pyruvate carboxylase. Simultaneously in the mitochondria, calcium transferred through mitochondria-associated membranes activates several dehydrogenases in the tricarboxylic acid cycle, correlated with an increase in mitochondrial energy expenditure and reduction in ectopic lipid. This model suggests that short-term, cyclic treatment with glucagon or other INSP3R1 antagonists could hold promise as a means to reset lipid homeostasis in patients with NAFLD.
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Affiliation(s)
- Rachel J. Perry
- Section of Endocrinology & Metabolism, Department of Internal Medicine, and Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT
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21
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Mediators of Amylin Action in Metabolic Control. J Clin Med 2022; 11:jcm11082207. [PMID: 35456307 PMCID: PMC9025724 DOI: 10.3390/jcm11082207] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 02/06/2023] Open
Abstract
Amylin (also called islet amyloid polypeptide (IAPP)) is a pancreatic beta-cell hormone that is co-secreted with insulin in response to nutrient stimuli. The last 35 years of intensive research have shown that amylin exerts important physiological effects on metabolic control. Most importantly, amylin is a physiological control of meal-ending satiation, and it limits the rate of gastric emptying and reduces the secretion of pancreatic glucagon, in particular in postprandial states. The physiological effects of amylin and its analogs are mediated by direct brain activation, with the caudal hindbrain playing the most prominent role. The clarification of the structure of amylin receptors, consisting of the calcitonin core receptor plus receptor-activity modifying proteins, aided in the development of amylin analogs with a broad pharmacological profile. The general interest in amylin physiology and pharmacology was boosted by the finding that amylin is a sensitizer to the catabolic actions of leptin. Today, amylin derived analogs are considered to be among the most promising approaches for the pharmacotherapy against obesity. At least in conjunction with insulin, amylin analogs are also considered important treatment options in diabetic patients, so that new drugs may soon be added to the only currently approved compound pramlintide (Symlin®). This review provides a brief summary of the physiology of amylin’s mode of actions and its role in the control of the metabolism, in particular energy intake and glucose metabolism.
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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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Gu L, Wang D, Cui X, Wei T, Yang K, Yang J, Wei R, Hong T. Combination of GLP-1 Receptor Activation and Glucagon Blockage Promotes Pancreatic β-Cell Regeneration In Situ in Type 1 Diabetic Mice. J Diabetes Res 2021; 2021:7765623. [PMID: 39280767 PMCID: PMC11401728 DOI: 10.1155/2021/7765623] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/01/2021] [Accepted: 10/23/2021] [Indexed: 09/18/2024] Open
Abstract
Pancreatic β-cell neogenesis in vivo holds great promise for cell replacement therapy in diabetic patients, and discovering the relevant clinical therapeutic strategies would push it forward to clinical application. Liraglutide, a widely used antidiabetic glucagon-like peptide-1 (GLP-1) analog, has displayed diverse β-cell-protective effects in type 2 diabetic animals. Glucagon receptor (GCGR) monoclonal antibody (mAb), a preclinical agent that blocks glucagon pathway, can promote the recovery of functional β-cell mass in type 1 diabetic mice. Here, we conducted a 4-week treatment of the two drugs alone or in combination in type 1 diabetic mice. Although liraglutide neither lowered the blood glucose level nor increased the plasma insulin level, the immunostaining showed that liraglutide expanded β-cell mass through self-replication, differentiation from precursor cells, and transdifferentiation from pancreatic α cells to β-cells. The pancreatic β-cell mass increased more significantly after GCGR mAb treatment, while the combination group did not further increase the pancreatic β-cell area. However, compared with the GCGR mAb group, the combined treatment reduced the plasma glucagon level and increased the proportion of β-cells/α-cells. Our study evaluated the effects of liraglutide, GCGR mAb monotherapy, and combined strategy in glucose control and islet β-cell regeneration and provided useful clues for the future clinical application in type 1 diabetes.
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Affiliation(s)
- Liangbiao Gu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Dandan Wang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Xiaona Cui
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Kun Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
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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: 26] [Impact Index Per Article: 8.7] [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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25
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Rajak S, Xie S, Tewari A, Raza S, Wu Y, Bay BH, Yen PM, Sinha RA. MTORC1 inhibition drives crinophagic degradation of glucagon. Mol Metab 2021; 53:101286. [PMID: 34224916 PMCID: PMC8327649 DOI: 10.1016/j.molmet.2021.101286] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 11/28/2022] Open
Abstract
Objective Crinophagy is a secretory granule-specific autophagic process that regulates hormone content and secretion in endocrine cells. However, despite being one of the earliest described autophagic processes, its mechanism of action and regulation in mammalian cells remains unclear. Methods and results Here, we examined mammalian crinophagy and its modulation that regulate hormone secretion in a glucagon-producing mouse pancreatic α-cell line, alpha TC1 clone 9 (αTC9), and in vivo. Western blot, electron microscopy, and immunofluorescence analyses were performed to study crinophagy and glucagon secretion in αTC9 cells and C57BL/6 mice, in response to the mammalian target of rapamycin complex 1 (MTORC1) inhibitor rapamycin. Amino acid depletion and pharmacological inhibition of MTORC1 increased the shuttling of glucagon-containing secretory granules into lysosomes for crinophagic degradation to reduce glucagon secretion through a macroautophagy-independent mechanism. Furthermore, MTORC1 inhibition reduced both intracellular and secreted glucagon in rapamycin-treated mice, in response to hypoglycaemia. Conclusion In summary, we have identified a novel crinophagic mechanism of intracellular glucagon turnover in pancreatic α-cells regulated by MTORC1 signalling. Crinophagy regulates α-cell glucagon levels. MTORC1 inhibition induces glucagon crinophagy. Glucagon crinophagy is macroautophagy-independent.
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Affiliation(s)
- Sangam Rajak
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
| | - Sherwin Xie
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, 169587, Singapore
| | - Archana Tewari
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
| | - Sana Raza
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Boon-Huat Bay
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Paul M Yen
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, 169587, Singapore
| | - Rohit A Sinha
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India.
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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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27
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Ng XW, Chung YH, Piston DW. Intercellular Communication in the Islet of Langerhans in Health and Disease. Compr Physiol 2021; 11:2191-2225. [PMID: 34190340 PMCID: PMC8985231 DOI: 10.1002/cphy.c200026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon, and somatostatin from the β-, α-, and δ-cells, respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca2+ activity, as well as the two-phase insulin secretion profile, are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and nonhormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this article, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types. © 2021 American Physiological Society. Compr Physiol 11:2191-2225, 2021.
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Affiliation(s)
- Xue W Ng
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - Yong H Chung
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
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28
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Yang B, Gelfanov VM, Perez-Tilve D, DuBois B, Rohlfs R, Levy J, Douros JD, Finan B, Mayer JP, DiMarchi RD. Optimization of Truncated Glucagon Peptides to Achieve Selective, High Potency, Full Antagonists. J Med Chem 2021; 64:4697-4708. [PMID: 33821647 DOI: 10.1021/acs.jmedchem.0c02069] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Antagonism of glucagon's biological action is a proven strategy for decreasing glucose in diabetic animals and patients. To achieve full, potent, and selective suppression, we chemically optimized N-terminally truncated glucagon fragments for the identification and establishment of the minimum sequence peptide, [Glu9]glucagon(6-29) amide (11) as a full antagonist in cellular signaling and receptor binding (IC50 = 36 nM). Substitution of Phe6 with l-3-phenyllactic acid (Pla) produced [Pla6, Glu9]glucagon(6-29) amide (21), resulting in a 3-fold improvement in receptor binding (IC50 = 12 nM) and enhanced antagonist potency. Further substitution of Glu9 and Asn28 with aspartic acid yielded [Pla6, Asp28]glucagon amide (26), which demonstrated a further increase in inhibitory potency (IC50 = 9 nM), and improved aqueous solubility. Peptide 26 and a palmitoylated analogue, [Pla6, Lys10(γGluγGlu-C16), Asp28]glucagon(6-29) amide (31), displayed sustained duration in vivo action that successfully reversed glucagon-induced glucose elevation in mice.
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Affiliation(s)
- Bin Yang
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.,Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - Vasily M Gelfanov
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States.,Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - Diego Perez-Tilve
- Department of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, United States
| | - Barent DuBois
- Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - Rebecca Rohlfs
- Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - Jay Levy
- Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - Jonathan D Douros
- Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - Brian Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, Indiana 46241, United States
| | - John P Mayer
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Richard D DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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29
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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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30
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Lang S, Wei R, Wei T, Gu L, Feng J, Yan H, Yang J, Hong T. Glucagon receptor antagonism promotes the production of gut proglucagon-derived peptides in diabetic mice. Peptides 2020; 131:170349. [PMID: 32561493 DOI: 10.1016/j.peptides.2020.170349] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 12/23/2022]
Abstract
Glucagon is an essential regulator of glucose homeostasis, particularly in type 2 diabetes (T2D). Blocking the glucagon receptor (GCGR) in diabetic animals and humans has been shown to alleviate hyperglycemia and increase circulating glucagon-like peptide-1 (GLP-1) levels. However, the origin of the upregulated GLP-1 remains to be clarified. Here, we administered high-fat diet + streptozotocin-induced T2D mice and diabetic db/db mice with REMD 2.59, a fully competitive antagonistic human GCGR monoclonal antibody (mAb) for 12 weeks. GCGR mAb treatment decreased fasting blood glucose levels and increased plasma GLP-1 levels in the T2D mice. In addition, GCGR mAb upregulated preproglucagon gene expression and the contents of gut proglucagon-derived peptides, particularly GLP-1, in the small intestine and colon. Notably, T2D mice treated with GCGR mAb displayed a higher L-cell density in the small intestine and colon, which was associated with increased numbers of LK-cells coexpressing GLP-1 and glucose-dependent insulinotropic polypeptide and reduced L-cell apoptosis. Furthermore, GCGR mAb treatment upregulated GLP-1 production in the pancreas, which was detected at lower levels than in the intestine. Collectively, these results suggest that GCGR mAb can increase intestinal GLP-1 production and L-cell number by enhancing LK-cell expansion and inhibiting L-cell apoptosis in T2D.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Antibodies, Neutralizing/pharmacology
- Apoptosis/genetics
- Blood Glucose/metabolism
- Colon/drug effects
- Colon/metabolism
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diet, High-Fat/adverse effects
- Fasting/metabolism
- Gastric Inhibitory Polypeptide/genetics
- Gastric Inhibitory Polypeptide/metabolism
- Gene Expression Regulation
- Glucagon-Like Peptide 1/genetics
- Glucagon-Like Peptide 1/metabolism
- Humans
- Intestine, Small/drug effects
- Intestine, Small/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Pancreas/drug effects
- Pancreas/metabolism
- Proglucagon/genetics
- Proglucagon/metabolism
- Receptors, Glucagon/antagonists & inhibitors
- Receptors, Glucagon/genetics
- Receptors, Glucagon/metabolism
- Signal Transduction
- Streptozocin/administration & dosage
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Affiliation(s)
- 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
| | - 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
| | - Tianjiao 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
| | - Jin Feng
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA 93012, USA; Beijing Cosci-REMD, Beijing 102206, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, 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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31
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Cheng C, Jabri S, Taoka BM, Sinz CJ. Small molecule glucagon receptor antagonists: an updated patent review (2015–2019). Expert Opin Ther Pat 2020; 30:509-526. [DOI: 10.1080/13543776.2020.1769600] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Chen Cheng
- Merck & Co., Inc, South San Francisco, California, USA (MSD)
| | - Salman Jabri
- Merck & Co., Inc, South San Francisco, California, USA (MSD)
| | - Brandon M Taoka
- Merck & Co., Inc, South San Francisco, California, USA (MSD)
| | - Christopher J Sinz
- Merck & Co., Inc, South San Francisco, California, USA (MSD)
- Current Address: Maze Therapeutics, South San Francisco, California, USA
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Riopel M, Moon JS, Bandyopadhyay GK, You S, Lam K, Liu X, Kisseleva T, Brenner D, Lee YS. Inhibition of prolyl hydroxylases increases hepatic insulin and decreases glucagon sensitivity by an HIF-2α-dependent mechanism. Mol Metab 2020; 41:101039. [PMID: 32534258 PMCID: PMC7393408 DOI: 10.1016/j.molmet.2020.101039] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/02/2020] [Accepted: 06/04/2020] [Indexed: 02/06/2023] Open
Abstract
Objective Recent evidence indicates that inhibition of prolyl hydroxylase domain (PHD) proteins can exert beneficial effects to improve metabolic abnormalities in mice and humans. However, the underlying mechanisms are not clearly understood. This study was designed to address this question. Methods A pan-PHD inhibitor compound was injected into WT and liver-specific hypoxia-inducible factor (HIF)-2α KO mice, after onset of obesity and glucose intolerance, and changes in glucose and glucagon tolerance were measured. Tissue-specific changes in basal glucose flux and insulin sensitivity were also measured by hyperinsulinemic euglycemic clamp studies. Molecular and cellular mechanisms were assessed in normal and type 2 diabetic human hepatocytes, as well as in mouse hepatocytes. Results Administration of a PHD inhibitor compound (PHDi) after the onset of obesity and insulin resistance improved glycemic control by increasing insulin and decreasing glucagon sensitivity in mice, independent of body weight change. Hyperinsulinemic euglycemic clamp studies revealed that these effects of PHDi treatment were mainly due to decreased basal hepatic glucose output and increased liver insulin sensitivity. Hepatocyte-specific deletion of HIF-2α markedly attenuated these effects of PHDi treatment, showing PHDi effects are HIF-2α dependent. At the molecular level, HIF-2α induced increased Irs2 and cyclic AMP-specific phosphodiesterase gene expression, leading to increased and decreased insulin and glucagon signaling, respectively. These effects of PHDi treatment were conserved in human and mouse hepatocytes. Conclusions Our results elucidate unknown mechanisms for how PHD inhibition improves glycemic control through HIF-2α-dependent regulation of hepatic insulin and glucagon sensitivity. PHD inhibitor treatment improves glycemic control in obese glucose-intolerant mice. PHD inhibitor treatment decreases liver glucagon sensitivity in obese mice. The effects of PHD inhibition on glycemic control is hepatocyte HIF-2α-dependent. PHD inhibitor treatment stimulates HIF-2α-dependent cAMP-specific PDE expression. In human and mouse hepatocytes, PHD inhibitor treatment suppresses glucagon signaling.
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Affiliation(s)
- Matthew Riopel
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jae-Su Moon
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Gautam K Bandyopadhyay
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Seohee You
- Cardiovascular and Metabolism, Janssen Research & Development, Spring House, PA, USA
| | - Kevin Lam
- Department of Surgery, University of California, San Diego, La Jolla, CA, USA
| | - Xiao Liu
- Department of Surgery, University of California, San Diego, La Jolla, CA, USA
| | - Tatiana Kisseleva
- Department of Surgery, University of California, San Diego, La Jolla, CA, USA
| | - David Brenner
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Yun Sok Lee
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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Lang S, Yang J, Yang K, Gu L, Cui X, Wei T, Liu J, Le Y, Wang H, Wei R, Hong T. Glucagon receptor antagonist upregulates circulating GLP-1 level by promoting intestinal L-cell proliferation and GLP-1 production in type 2 diabetes. BMJ Open Diabetes Res Care 2020; 8:8/1/e001025. [PMID: 32139602 PMCID: PMC7059498 DOI: 10.1136/bmjdrc-2019-001025] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/24/2020] [Accepted: 01/26/2020] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Glucagon receptor (GCGR) blockage improves glycemic control and increases circulating glucagon-like peptide-1 (GLP-1) level in diabetic animals and humans. The elevated GLP-1 has been reported to be involved in the hypoglycemic effect of GCGR blockage. However, the source of this elevation remains to be clarified. RESEARCH DESIGN AND METHODS REMD 2.59, a human GCGR monoclonal antibody (mAb), was administrated for 12 weeks in db/db mice and high-fat diet+streptozotocin (HFD/STZ)-induced type 2 diabetic (T2D) mice. Blood glucose, glucose tolerance and plasma GLP-1 were evaluated during the treatment. The gut length, epithelial area, and L-cell number and proliferation were detected after the mice were sacrificed. Cell proliferation and GLP-1 production were measured in mouse L-cell line GLUTag cells, and primary mouse and human enterocytes. Moreover, GLP-1 receptor (GLP-1R) antagonist or protein kinase A (PKA) inhibitor was used in GLUTag cells to determine the involved signaling pathways. RESULTS Treatment with the GCGR mAb lowered blood glucose level, improved glucose tolerance and elevated plasma GLP-1 level in both db/db and HFD/STZ-induced T2D mice. Besides, the treatment promoted L-cell proliferation and LK-cell expansion, and increased the gut length, epithelial area and L-cell number in these two T2D mice. Similarly, our in vitro study showed that the GCGR mAb promoted L-cell proliferation and increased GLP-1 production in GLUTag cells, and primary mouse and human enterocytes. Furthermore, either GLP-1R antagonist or PKA inhibitor diminished the effects of GCGR mAb on L-cell proliferation and GLP-1 production. CONCLUSIONS The elevated circulating GLP-1 level by GCGR mAb is mainly due to intestinal L-cell proliferation and GLP-1 production, which may be mediated via GLP-1R/PKA signaling pathways. Therefore, GCGR mAb represents a promising strategy to improve glycemic control and restore the impaired GLP-1 production in T2D.
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Affiliation(s)
- Shan Lang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Kun Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Liangbiao Gu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Xiaona Cui
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Junling Liu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Yunyi Le
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Haining Wang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
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34
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Bich L, Mossio M, Soto AM. Glycemia Regulation: From Feedback Loops to Organizational Closure. Front Physiol 2020; 11:69. [PMID: 32132928 PMCID: PMC7040218 DOI: 10.3389/fphys.2020.00069] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/21/2020] [Indexed: 12/19/2022] Open
Abstract
Endocrinologists apply the idea of feedback loops to explain how hormones regulate certain bodily functions such as glucose metabolism. In particular, feedback loops focus on the maintenance of the plasma concentrations of glucose within a narrow range. Here, we put forward a different, organicist perspective on the endocrine regulation of glycaemia, by relying on the pivotal concept of closure of constraints. From this perspective, biological systems are understood as organized ones, which means that they are constituted of a set of mutually dependent functional structures acting as constraints, whose maintenance depends on their reciprocal interactions. Closure refers specifically to the mutual dependence among functional constraints in an organism. We show that, when compared to feedback loops, organizational closure can generate much richer descriptions of the processes and constraints at play in the metabolism and regulation of glycaemia, by making explicit the different hierarchical orders involved. We expect that the proposed theoretical framework will open the way to the construction of original mathematical models, which would provide a better understanding of endocrine regulation from an organicist perspective.
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Affiliation(s)
- Leonardo Bich
- IAS Research Centre for Life, Mind and Society, Department of Logic and Philosophy of Science, University of the Basque Country (UPV/EHU), San Sebastián, Spain
| | - Matteo Mossio
- Institut d'Histoire et de Philosophie des Sciences et des Techniques, CNRS/Université Paris 1, Paris, France
| | - Ana M Soto
- Tufts University School of Medicine, Boston, MA, United States.,Centre Cavaillès, République des Savoirs, CNRS, Collège de France et Ecole Normale Supérieure, Paris, France
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35
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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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36
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Chen LC, Fan ZY, Wang HY, Wen DC, Zhang SY. Effect of polysaccharides from adlay seed on anti-diabetic and gut microbiota. Food Funct 2020; 10:4372-4380. [PMID: 31276140 DOI: 10.1039/c9fo00406h] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diabetes is a chronic metabolic disease characterized by elevated blood glucose levels due to insulin resistance and β-cell dysfunction. This study aims to examine the effects of polysaccharides from adlay seeds (PAS) on hyperglycemia and gut microbiota in streptozocin (STZ)-induced diabetic mice. The administration of PAS in diabetic mice caused a significant decrease in the glucose level and serum levels of glycosylated hemoglobin (HbA1c). Similarly, PAS also showed decreased total cholesterol (TC) and triglyceride (TG) concentrations. Furthermore, a significant increase in the concentrations of glucagon-like peptide 1 (GLP-1) was observed. Unexpectedly, PAS reduced the concentrations of anti-amyloid beta (Aβ1-42) protein. Also, histopathological examination showed that PAS contributed to the reduction of STZ-lesioned pancreatic cells. Metformin treatment significantly reduced the diversity of the gut microbiota, while PAS treatment altered the diversity and composition of the microbiota. Collectively, our findings demonstrate that the hypoglycemic effects of PAS in type-2 diabetic mice (T2D) may be associated with the regulation of the intestinal microbiota and its metabolic pathways.
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Affiliation(s)
- Li-Chun Chen
- College of Food & Biology Engineering, Zhejiang Gongshang University, Hangzhou, Zhejiang 310035, China.
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37
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Jiang HC, Chen XR, Sun HF, Nie YW. Tumor promoting effects of glucagon receptor: a promising biomarker of papillary thyroid carcinoma via regulating EMT and P38/ERK pathways. Hum Cell 2019; 33:175-184. [PMID: 31782107 DOI: 10.1007/s13577-019-00284-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/14/2019] [Indexed: 02/07/2023]
Abstract
Glucagon is a crucial hormone involved in the maintenance of glucose homeostasis. Large efforts to define the role of glucagon receptor (GCGR) have been continuously made in recent years, but it is still incomplete about its function and mechanism. We performed this study to verify its potential impacts on papillary thyroid carcinoma (PTC) progression. Correlation between GCGR expression and PTC was elaborated using The Cancer Genome Atlas (TCGA) database. The Kaplan-Meier method was used to analyze the connection between GCGR expression and prognosis of PTC patients. GCGR expression was measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis; simultaneously, cell viability was elucidated using cell proliferation and colony formation assays following siRNAs strategy. Transwell analyses were conducted to measure the invasion and migration of PTC cells. Flow cytometry analysis was conducted to examine apoptotic ability. The cAMP ELISA kit was employed to measure the cAMP level in PTC cells. Our data determined that the expression level of GCGR was increased in PTC tissues and cells in contrast to normal tissues and Nthy-ori 3-1, respectively. Up-regulated GCGR expression was linked with the lower survival rate in patients with PTC. Functional analysis in vitro suggested that GCGR knockdown attenuated PTC cell proliferation, colony formation, invasion, and migration whilst intensified apoptosis. Down-regulated GCGR was able to increase cAMP level. Furthermore, reduction of GCGR could result in the inactivation of epithelial-mesenchymal transition (EMT) and P38/ERK pathways. In conclusion, the findings of this study disclosed that GCGR promoted PTC cell behaviors by mediating the EMT and P38/ERK pathways, serving as a potential diagnostic and prognostic biomarker as well as therapeutic target for PTC.
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Affiliation(s)
- Hong-Chun Jiang
- Eye 3 Division of Red Flag Hospital of Mudanjiang Medical University, Mudanjiang, 157000, Heilongjiang, People's Republic of China
| | - Xiang-Ru Chen
- Color Doppler Ultrasound Room, The Second Affiliated Hospital of Mudanjiang Medical University, Mudanjiang, 157000, Heilongjiang, People's Republic of China
| | - Hai-Feng Sun
- Department of Endocrinology, The Second Affiliated Hospital of Mudanjiang Medical University, Mudanjiang, 157000, Heilongjiang, People's Republic of China
| | - Yuan-Wen Nie
- Hepatobiliary Surgery, The Second Affiliated Hospital of Mudanjiang Medical University, Mudanjiang, 157000, Heilongjiang, People's Republic of China.
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38
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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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39
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Sharma AX, Quittner-Strom EB, Lee Y, Johnson JA, Martin SA, Yu X, Li J, Lu J, Cai Z, Chen S, Wang MY, Zhang Y, Pearson MJ, Dorn AC, McDonald JG, Gordillo R, Yan H, Thai D, Wang ZV, Unger RH, Holland WL. Glucagon Receptor Antagonism Improves Glucose Metabolism and Cardiac Function by Promoting AMP-Mediated Protein Kinase in Diabetic Mice. Cell Rep 2019; 22:1760-1773. [PMID: 29444429 PMCID: PMC5978750 DOI: 10.1016/j.celrep.2018.01.065] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/30/2017] [Accepted: 01/22/2018] [Indexed: 12/13/2022] Open
Abstract
The antidiabetic potential of glucagon receptor antagonism presents an opportunity for use in an insulin-centric clinical environment. To investigate the metabolic effects of glucagon receptor antagonism in type 2 diabetes, we treated Leprdb/db and Lepob/ob mice with REMD 2.59, a human monoclonal antibody and competitive antagonist of the glucagon receptor. As expected, REMD 2.59 suppresses hepatic glucose production and improves glycemia. Surprisingly, it also enhances insulin action in both liver and skeletal muscle, coinciding with an increase in AMP-activated protein kinase (AMPK)-mediated lipid oxidation. Furthermore, weekly REMD 2.59 treatment over a period of months protects against diabetic cardiomyopathy. These functional improvements are not derived simply from correcting the systemic milieu; nondiabetic mice with cardiac-specific overexpression of lipoprotein lipase also show improvements in contractile function after REMD 2.59 treatment. These observations suggest that hyperglucagonemia enables lipotoxic conditions, allowing the development of insulin resistance and cardiac dysfunction during disease progression.
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Affiliation(s)
- Ankit X Sharma
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ezekiel B Quittner-Strom
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Young Lee
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - Joshua A Johnson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Sarah A Martin
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Xinxin Yu
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - Jianping Li
- Division of Cardiology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - John Lu
- REMD Biotherapeutics Inc., Camarillo, CA 93012, USA
| | | | - Shiuhwei Chen
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - May-Yun Wang
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - Yiyi Zhang
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Mackenzie J Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Andie C Dorn
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Jeffrey G McDonald
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ruth Gordillo
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Hai Yan
- REMD Biotherapeutics Inc., Camarillo, CA 93012, USA
| | - Dung Thai
- REMD Biotherapeutics Inc., Camarillo, CA 93012, USA
| | - Zhao V Wang
- Division of Cardiology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Roger H Unger
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA.
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40
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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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41
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Gao C, Ren SV, Yu J, Baal U, Thai D, Lu J, Zeng C, Yan H, Wang Y. Glucagon Receptor Antagonism Ameliorates Progression of Heart Failure. JACC Basic Transl Sci 2019; 4:161-172. [PMID: 31061918 PMCID: PMC6488764 DOI: 10.1016/j.jacbts.2018.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 11/01/2018] [Accepted: 11/02/2018] [Indexed: 02/08/2023]
Abstract
Mice were treated with a fully human monoclonal glucagon receptor antagonistic antibody REMD2.59 following myocardial infarction or pressure overload. REMD2.59 treatment blunted cardiac hypertrophy and fibrotic remodeling, and attenuated contractile dysfunction at 4 weeks after myocardial infarction. In addition, REMD2.59 treatment at the onset of pressure overload significantly suppressed cardiac hypertrophy and chamber dilation with marked preservation of cardiac systolic and diastolic function. Initiation of REMD2.59 treatment 2 weeks after pressure overload significantly blunted the progression of cardiac pathology. These results provide the first in vivo proof-of-concept evidence that glucagon receptor antagonism is a potentially efficacious therapy to ameliorate both onset and progression of heart failure.
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Affiliation(s)
- Chen Gao
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Address for correspondence: Dr. Yibin Wang or Dr. Chen Gao, Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, 650 Charles E. Young Drive, Room CHS 37-200J, Los Angeles, California 90095.
| | - Shuxun Vincent Ren
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Junyi Yu
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Ulysis Baal
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Dung Thai
- REMD Biotherapeutics, Camarillo, California
- Beijing Cosci-REMD Biotherapeutics, Beijing, China
| | - John Lu
- REMD Biotherapeutics, Camarillo, California
- Beijing Cosci-REMD Biotherapeutics, Beijing, China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, California
- Beijing Cosci-REMD Biotherapeutics, Beijing, China
| | - Yibin Wang
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Address for correspondence: Dr. Yibin Wang or Dr. Chen Gao, Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, 650 Charles E. Young Drive, Room CHS 37-200J, Los Angeles, California 90095.
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42
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Gu L, Cui X, Lang S, Wang H, Hong T, Wei R. Glucagon receptor antagonism increases mouse pancreatic δ-cell mass through cell proliferation and duct-derived neogenesis. Biochem Biophys Res Commun 2019; 512:864-870. [PMID: 30929915 DOI: 10.1016/j.bbrc.2019.03.148] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 03/22/2019] [Indexed: 01/05/2023]
Abstract
Pancreatic δ-cells, which produce somatostatin, play an indispensable role in glucose homeostasis by inhibiting glucagon and insulin secretion in a paracrine manner. Recent studies have shown that δ-cells are couple with β-cells to suppress α-cell activity. Under certain circumstances, δ-cells could also be trans-differentiated into insulin-producing β-cells. Thus, pancreatic islet may benefit from δ-cell hyperplasia. However, an effective way to increase δ-cell mass has been rarely reported. Here, we found that REMD 2.59, a human monoclonal antibody and competitive antagonist of the glucagon receptor, massively boosted δ-cell number and increased plasma somatostatin level in both normoglycemic and type 1 diabetic (T1D) mice. The increased δ-cells were due to both δ-cell proliferation and derivation of duct lining cells. Notably, the enlarged δ-cell mass could reduce β-cell burdens by inducing FoxO1 nuclear translocation in normoglycemic mice. Moreover, some somatostatin-positive cells were co-localized with C-peptide in T1D mice, suggesting that δ-cells might be a source of the newborn β-cells. Collectively, these observations suggest that treatment with the glucagon receptor monoclonal antibody can increase pancreatic δ-cell mass by promoting self-replication and inducing duct-derived neogenesis both in normoglycemia and diabetic mice.
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Affiliation(s)
- Liangbiao Gu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Xiaona Cui
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Shan Lang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Haining Wang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China.
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Dusaulcy R, Handgraaf S, Visentin F, Howald C, Dermitzakis ET, Philippe J, Gosmain Y. High-fat diet impacts more changes in beta-cell compared to alpha-cell transcriptome. PLoS One 2019; 14:e0213299. [PMID: 30849121 PMCID: PMC6407777 DOI: 10.1371/journal.pone.0213299] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 02/19/2019] [Indexed: 12/27/2022] Open
Abstract
Characterization of endocrine-cell functions and associated molecular signatures in diabetes is crucial to better understand why and by which mechanisms alpha and beta cells cause and perpetuate metabolic abnormalities. The now recognized role of glucagon in diabetes control is a major incentive to have a better understanding of dysfunctional alpha cells. To characterize molecular alterations of alpha cells in diabetes, we analyzed alpha-cell transcriptome from control and diabetic mice using diet-induced obesity model. To this aim, we quantified the expression levels of total mRNAs from sorted alpha and beta cells of low-fat and high-fat diet-treated mice through RNAseq experiments, using a transgenic mouse strain allowing collections of pancreatic alpha- and beta-cells after 16 weeks of diet. We now report that pancreatic alpha cells from obese hyperglycemic mice displayed minor variations of their transcriptome compared to controls. Depending on analyses, we identified 11 to 39 differentially expressed genes including non-alpha cell markers mainly due to minor cell contamination during purification process. From these analyses, we identified three new target genes altered in diabetic alpha cells and potently involved in cellular stress and exocytosis (Upk3a, Adcy1 and Dpp6). By contrast, analysis of the beta-cell transcriptome from control and diabetic mice revealed major alterations of specific genes coding for proteins involved in proliferation and secretion. We conclude that alpha cell transcriptome is less reactive to HFD diet compared to beta cells and display adaptations to cellular stress and exocytosis.
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Affiliation(s)
- Rodolphe Dusaulcy
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Sandra Handgraaf
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Florian Visentin
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Cedric Howald
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Emmanouil T. Dermitzakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, Geneva, Switzerland
| | - Jacques Philippe
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Yvan Gosmain
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
- * E-mail:
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Asadi F, Dhanvantari S. Plasticity in the Glucagon Interactome Reveals Novel Proteins That Regulate Glucagon Secretion in α-TC1-6 Cells. Front Endocrinol (Lausanne) 2019; 9:792. [PMID: 30713523 PMCID: PMC6346685 DOI: 10.3389/fendo.2018.00792] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 12/17/2018] [Indexed: 12/27/2022] Open
Abstract
Glucagon is stored within the secretory granules of pancreatic alpha cells until stimuli trigger its release. The alpha cell secretory responses to the stimuli vary widely, possibly due to differences in experimental models or microenvironmental conditions. We hypothesized that the response of the alpha cell to various stimuli could be due to plasticity in the network of proteins that interact with glucagon within alpha cell secretory granules. We used tagged glucagon with Fc to pull out glucagon from the enriched preparation of secretory granules in α-TC1-6 cells. Isolation of secretory granules was validated by immunoisolation with Fc-glucagon and immunoblotting for organelle-specific proteins. Isolated enriched secretory granules were then used for affinity purification with Fc-glucagon followed by liquid chromatography/tandem mass spectrometry to identify secretory granule proteins that interact with glucagon. Proteomic analyses revealed a network of proteins containing glucose regulated protein 78 KDa (GRP78) and histone H4. The interaction between glucagon and the ER stress protein GRP78 and histone H4 was confirmed through co-immunoprecipitation of secretory granule lysates, and colocalization immunofluorescence confocal microscopy. Composition of the protein networks was altered at different glucose levels (25 vs. 5.5 mM) and in response to the paracrine inhibitors of glucagon secretion, GABA and insulin. siRNA-mediated silencing of a subset of these proteins revealed their involvement in glucagon secretion in α-TC1-6 cells. Therefore, our results show a novel and dynamic glucagon interactome within α-TC1-6 cell secretory granules. We suggest that variations in the alpha cell secretory response to stimuli may be governed by plasticity in the glucagon "interactome."
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Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
- Metabolism, Diabetes and Imaging Programs, Lawson Health Research Institute, London, ON, Canada
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Zhang B, Pan Y, Xu L, Tang D, Dorfman RG, Zhou Q, Yin Y, Li Y, Zhou L, Zhao S, Zou X, Wang L, Zhang M. Berberine promotes glucose uptake and inhibits gluconeogenesis by inhibiting deacetylase SIRT3. Endocrine 2018; 62:576-587. [PMID: 30117113 DOI: 10.1007/s12020-018-1689-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/18/2018] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Many studies have confirmed the glucose-lowering effect of berberine in type 2 diabetes patients. Although the mechanism of action of berberine involves the improvement of insulin sensitivity, its hypoglycemic mechanism remains elusive. Here we show a new mechanism by which berberine antagonizes glucagon signaling and find that SIRT3 is involved in the hypoglycemic effect of berberine. METHODS Gene knockout and overexpression were used to assess the inhibitory effect of berberine on SIRT3. Downstream signaling pathways and the hypoglycemic effect of SIRT3 were evaluated by immunoblotting and metabolic monitoring. RESULTS We found that berberine led to mitochondrial dysfunction and AMP accumulation by inhibiting deacetylase SIRT3. We confirmed that AMP accumulation activated the AMPK signaling pathway and further promoted glucose uptake. Simultaneously, AMP accumulation reduced cyclic AMP (cAMP) levels and abrogated the phosphorylation of critical protein targets of protein kinase A (PKA). Furthermore, we found that phosphoenolpyruvate carboxykinase 1 (PEPCK1) is a key gluconeogenesis enzyme that can be stabilized by glucagon. Berberine caused significant PEPCK1 ubiquitination and degradation by antagonizing glucagon and was accompanied by high levels of PEPCK1 acetylation. Interestingly, berberine-induced glucagon inhibition is independent of AMPK activation. The in vivo data from sirt3 knockout mice were further confirmed by the in vitro experiments. CONCLUSIONS Berberine promotes glucose uptake and inhibits gluconeogenesis by inhibiting SIRT3, and regulating mitochondria-related pathways may provide a novel approach to the development of antidiabetic drugs.
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Affiliation(s)
- Bingjie Zhang
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
- Department of Endocrinology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Yida Pan
- Department of Digestive Diseases of Huashan Hospital, Fudan University, Shanghai, China
| | - Lei Xu
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Dehua Tang
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | | | - Qian Zhou
- School of Life Sciences, Fudan University, Shanghai, China
| | - Yuyao Yin
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Yang Li
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Lixing Zhou
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Shimin Zhao
- School of Life Sciences, Fudan University, Shanghai, China
- Key laboratory of Reproduction Regulation of NPFPC (SIPPR, IRD), Fudan University, Shanghai, China
| | - Xiaoping Zou
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China
| | - Lei Wang
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China.
| | - Mingming Zhang
- Department of Gastroenterology, Drum Tower hospital affiliated to Nanjing University Medical School, Nanjing University, Nanjing, China.
- School of Life Sciences, Fudan University, Shanghai, China.
- Key laboratory of Reproduction Regulation of NPFPC (SIPPR, IRD), Fudan University, Shanghai, China.
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Emfinger CH, Yan Z, Welscher A, Hung P, McAllister W, Hruz PW, Nichols CG, Remedi MS. Contribution of systemic inflammation to permanence of K ATP-induced neonatal diabetes in mice. Am J Physiol Endocrinol Metab 2018; 315:E1121-E1132. [PMID: 30226997 PMCID: PMC6336961 DOI: 10.1152/ajpendo.00137.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Gain-of-function (GOF) mutations in the ATP-sensitive potassium (KATP) channels cause neonatal diabetes. Despite the well-established genetic root of the disease, pathways modulating disease severity and treatment effectiveness remain poorly understood. Patient phenotypes can vary from severe diabetes to remission, even in individuals with the same mutation and within the same family, suggesting that subtle modifiers can influence disease outcome. We have tested the underlying mechanism of transient vs. permanent neonatal diabetes in KATP-GOF mice treated for 14 days with glibenclamide. Some KATP-GOF mice show remission of diabetes and enhanced insulin sensitivity long after diabetes treatment has ended, while others maintain severe insulin-resistance. However, insulin sensitivity is not different between the two groups before or during diabetes induction, suggesting that improved sensitivity is a consequence, rather than the cause of, remission, implicating other factors modulating glucose early in diabetes progression. Leptin, glucagon, insulin, and glucagon-like peptide-1 are not different between remitters and nonremitters. However, liver glucose production is significantly reduced before transgene induction in remitter, relative to nonremitter and nontreated, mice. Surprisingly, while subsequent remitter animals exhibited normal serum cytokines, nonremitter mice showed increased cytokines, which paralleled the divergence in blood glucose. Together, these results suggest that systemic inflammation may play a role in the remitting versus non-remitting outcome. Supporting this conclusion, treatment with the anti-inflammatory meloxicam significantly increased the fraction of remitting animals. Beyond neonatal diabetes, the potential for inflammation and glucose production to exacerbate other forms of diabetes from a compensated state to a glucotoxic state should be considered.
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Affiliation(s)
- Christopher H Emfinger
- Department of Medicine, Washington University in St. Louis , St. Louis, Missouri
- Department of Cell Biology and Physiology, Washington University in St. Louis , St. Louis, Missouri
- Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis , St. Louis, Missouri
| | - Zihan Yan
- Department of Medicine, Washington University in St. Louis , St. Louis, Missouri
| | - Alecia Welscher
- Department of Medicine, Washington University in St. Louis , St. Louis, Missouri
| | - Peter Hung
- Department of Cell Biology and Physiology, Washington University in St. Louis , St. Louis, Missouri
| | - William McAllister
- Department of Medicine, Washington University in St. Louis , St. Louis, Missouri
| | - Paul W Hruz
- Department of Pediatrics, Washington University in St. Louis , St. Louis, Missouri
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University in St. Louis , St. Louis, Missouri
- Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis , St. Louis, Missouri
| | - Maria S Remedi
- Department of Medicine, Washington University in St. Louis , St. Louis, Missouri
- Department of Cell Biology and Physiology, Washington University in St. Louis , St. Louis, Missouri
- Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis , St. Louis, Missouri
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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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Galkina SI, Fedorova NV, Ksenofontov AL, Stadnichuk VI, Baratova LA, Sud'Ina GF. Neutrophils as a source of branched-chain, aromatic and positively charged free amino acids. Cell Adh Migr 2018; 13:98-105. [PMID: 30359173 PMCID: PMC6527394 DOI: 10.1080/19336918.2018.1540903] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Neutrophils release branched-chain (valine, isoleucine, leucine), aromatic (tyrosine, phenylalanine) and positively charged free amino acids (arginine, ornithine, lysine, hydroxylysine, histidine) when adhere and spread onto fibronectin. In the presence of agents that impair cell spreading or adhesion (cytochalasin D, fMLP, nonadhesive substrate), neutrophils release the same amino acids, except for a sharp decrease in hydroxylysine and an increase in phenylalanine, indicating their special connection with cell adhesion. Plasma of patients with diabetes is characterized by an increased content of branched-chain and aromatic amino acids and a reduced ratio of arginine/ornithine compared to healthy human plasma. Our data showed that the secretion of neutrophils, regardless of their adhesion state, can contribute to this shift in the amino acid content. Abbreviations: BCAAs: branched-chain amino acids; Е2: 17β-estradiol; LPS: lipopolysaccharide from Salmonella enterica serovar Typhimurium; fMLP: N-formylmethionyl-leucyl-phenylalanine.
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Affiliation(s)
- Svetlana I Galkina
- a A. N. Belozersky Institute of Physico-Chemical Biology , Lomonosov Moscow State University , Moscow , Russia
| | - Natalia V Fedorova
- a A. N. Belozersky Institute of Physico-Chemical Biology , Lomonosov Moscow State University , Moscow , Russia
| | - Alexander L Ksenofontov
- a A. N. Belozersky Institute of Physico-Chemical Biology , Lomonosov Moscow State University , Moscow , Russia
| | | | - Ludmila A Baratova
- a A. N. Belozersky Institute of Physico-Chemical Biology , Lomonosov Moscow State University , Moscow , Russia
| | - Galina F Sud'Ina
- a A. N. Belozersky Institute of Physico-Chemical Biology , Lomonosov Moscow State University , Moscow , Russia
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Design, synthesis, and effects of novel phenylpyrimidines as glucagon receptor antagonists. Bioorg Med Chem 2018; 26:5701-5710. [PMID: 30366787 DOI: 10.1016/j.bmc.2018.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/16/2018] [Accepted: 10/18/2018] [Indexed: 11/20/2022]
Abstract
The hormone glucagon increases blood glucose levels through increasing hepatic glucose output. In diabetic patients, dysregulation of glucagon secretion contributes to hyperglycemia. Thus, the inhibition of glucagon receptor is one target for the treatment of hyperglycemia in type 2 diabetes. Here we designed and synthesized a series of small molecules based on phenylpyrimidine. Of these, the compound (R)-7a most significantly decreased the glucagon-induced cAMP production and glucagon-induced glucose production during in vitro and in vivo assays. In addition, (R)-7a showed good efficacy in glucagon challenge tests and lowered blood glucose levels in diabetic db/db mice. Our results suggest that the compound (R)-7a could be a potential glucose-lowering agent for treating type 2 diabetes.
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50
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Capozzi ME, DiMarchi RD, Tschöp MH, Finan B, Campbell JE. Targeting the Incretin/Glucagon System With Triagonists to Treat Diabetes. Endocr Rev 2018; 39:719-738. [PMID: 29905825 PMCID: PMC7263842 DOI: 10.1210/er.2018-00117] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/07/2018] [Indexed: 02/07/2023]
Abstract
Glucagonlike peptide 1 (GLP-1) receptor agonists have been efficacious for the treatment of type 2 diabetes due to their ability to reduce weight and attenuate hyperglycemia. However, the activity of glucagonlike peptide 1 receptor-directed strategies is submaximal, and the only potent, sustainable treatment of metabolic dysfunction is bariatric surgery, necessitating the development of unique therapeutics. GLP-1 is structurally related to glucagon and glucose-dependent insulinotropic peptide (GIP), allowing for the development of intermixed, unimolecular peptides with activity at each of their respective receptors. In this review, we discuss the range of tissue targets and added benefits afforded by the inclusion of each of GIP and glucagon. We discuss considerations for the development of sequence-intermixed dual agonists and triagonists, highlighting the importance of evaluating balanced signaling at the targeted receptors. Several multireceptor agonist peptides have been developed and evaluated, and the key preclinical and clinical findings are reviewed in detail. The biological activity of these multireceptor agonists are founded in the success of GLP-1-directed strategies; by including GIP and glucagon components, these multireceptor agonists are thought to enhance GLP-1's activities by broadening the tissue targets and synergizing at tissues that express multiple receptors, such at the brain and pancreatic islet β cells. The development and utility of balanced, unimolecular multireceptor agonists provide both a useful tool for querying the actions of incretins and glucagon during metabolic disease and a unique drug class to treat type 2 diabetes with unprecedented efficacy.
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Affiliation(s)
- Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
| | - Richard D DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana
- Novo Nordisk Research Center, Indianapolis, Indiana
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Neuherberg, Germany
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Brian Finan
- Novo Nordisk Research Center, Indianapolis, Indiana
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University, Durham, North Carolina
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