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Thorens B. Neuronal glucose sensing mechanisms and circuits in the control of insulin and glucagon secretion. Physiol Rev 2024; 104:1461-1486. [PMID: 38661565 DOI: 10.1152/physrev.00038.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 04/16/2024] [Accepted: 04/20/2024] [Indexed: 04/26/2024] Open
Abstract
Glucose homeostasis is mainly under the control of the pancreatic islet hormones insulin and glucagon, which, respectively, stimulate glucose uptake and utilization by liver, fat, and muscle and glucose production by the liver. The balance between the secretions of these hormones is under the control of blood glucose concentrations. Indeed, pancreatic islet β-cells and α-cells can sense variations in glycemia and respond by an appropriate secretory response. However, the secretory activity of these cells is also under multiple additional metabolic, hormonal, and neuronal signals that combine to ensure the perfect control of glycemia over a lifetime. The central nervous system (CNS), which has an almost absolute requirement for glucose as a source of metabolic energy and thus a vital interest in ensuring that glycemic levels never fall below ∼5 mM, is equipped with populations of neurons responsive to changes in glucose concentrations. These neurons control pancreatic islet cell secretion activity in multiple ways: through both branches of the autonomic nervous system, through the hypothalamic-pituitary-adrenal axis, and by secreting vasopressin (AVP) in the blood at the level of the posterior pituitary. Here, we present the autonomic innervation of the pancreatic islets; the mechanisms of neuron activation by a rise or a fall in glucose concentration; how current viral tracing, chemogenetic, and optogenetic techniques allow integration of specific glucose sensing neurons in defined neuronal circuits that control endocrine pancreas function; and, finally, how genetic screens in mice can untangle the diversity of the hypothalamic mechanisms controlling the response to hypoglycemia.
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Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Kjeldsen SAS, Werge MP, Grandt J, Richter MM, Thing M, Hetland LE, Rashu EB, Jensen ASH, Winther-Sørensen M, Kellemann JS, Holst JJ, Junker AE, Serizawa RR, Vyberg M, Gluud LL, Wewer Albrechtsen NJ. Hepatic steatosis and not type 2 diabetes, body mass index, or hepatic fibrosis associates with hyperglucagonemia in individuals with steatotic liver disease. Am J Physiol Gastrointest Liver Physiol 2024; 327:G558-G570. [PMID: 39104323 DOI: 10.1152/ajpgi.00147.2024] [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: 05/17/2024] [Revised: 07/15/2024] [Accepted: 07/20/2024] [Indexed: 08/07/2024]
Abstract
Increased plasma concentrations of glucagon (hyperglucagonemia) are reported in patients with type 2 diabetes (T2D) and are considered a diabetogenic risk factor. Emerging evidence suggests that hepatic steatosis in obesity is causing a condition of resistance toward glucagon's effects on amino acid metabolism, resulting in an amino acid-induced hyperglucagonemia. We investigated the presence of hyperglucagonemia in individuals with biopsy-verified metabolic dysfunction-associated steatotic liver disease (MASLD), and whether body mass index (BMI), T2D, hepatic steatosis, and/or fibrosis contribute to this relationship. To dissect potential mechanisms, we also determined hepatic gene expression related to amino acid transport and catabolism. Individuals with MASLD had hyperglucagonemia {controls (n = 74) vs. MASLD (n = 106); median [Q1, Q3]; 4 [3, 7] vs. 8 [6, 13] pM), P < 0.0001} and were glucagon resistant (assessed by the glucagon-alanine index) {1.3 [0.9, 2.1] vs. 3.3 [2.1, 5.3] pM·mM, P < 0.0001}. These changes were associated with hepatic steatosis (P < 0.001, R2 > 0.25) independently of BMI, sex, age, and T2D. Plasma levels of glucagon were similar in individuals with MASLD when stratified on T2D status {MASLD-T2D (n = 52) vs. MASLD + T2D (n = 54); 8 [6, 11] vs. 8 [6, 13] pM, P = 0.34} and hepatic fibrosis {MASLD + F0 (n = 25) vs. MASLD + F1-F3 (n = 67); 8.4 [7.0, 13.3] vs. 7.9 [5.2, 11.6] pM, P = 0.43}. Obesity (BMI = 30 kg/m2) did not alter glucagon levels (P = 0.65) within groups (control/MASLD). The mRNA expression of proteins involved in amino acid transport and catabolism was downregulated in MASLD. Thus, relative hyperglucagonemia is present in individuals with biopsy-verified MASLD, and hepatic steatosis partially drives hyperglucagonemia and glucagon resistance, irrespective of T2D, BMI, and hepatic fibrosis.NEW & NOTEWORTHY Individuals with metabolic dysfunction-associated steatotic liver disease (MASLD) present with increased plasma levels of glucagon (hyperglucagonemia), irrespective of body mass index (BMI) and type 2 diabetes. Therefore, MASLD and the resultant hyperglucagonemia may act as a diabetogenic risk factor. Notably, hepatic steatosis was a significant contributor to the hyperglucagonemia in MASLD, potentially unveiling a pathway for the hyperglucagonemia in some patients with type 2 diabetes.
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Affiliation(s)
- Sasha A S Kjeldsen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg, Copenhagen, Denmark
| | - Mikkel P Werge
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Josephine Grandt
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Michael M Richter
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mira Thing
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Liv E Hetland
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Elias B Rashu
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Anne-Sofie H Jensen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg, Copenhagen, Denmark
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Marie Winther-Sørensen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg, Copenhagen, Denmark
| | - Jesper Sloth Kellemann
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg, 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
| | - Anders E Junker
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Reza R Serizawa
- Department of Pathology, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
| | - Mogens Vyberg
- Department of Pathology, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
- Department of Clinical Medicine, Center for RNA Medicine, Aalborg University, Copenhagen, Denmark
| | - Lise Lotte Gluud
- Gastro Unit, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Han H, Zhang Z, Xu B, Ding L, Yang H, He T, Du X, Pei X, Fu X. Integrated transcriptomic and metabolomic analysis reveals the underlying mechanisms for male reproductive toxicity of polystyrene nanoplastics in mouse spermatocyte-derived GC-2spd(ts) cells. Toxicol In Vitro 2024; 100:105893. [PMID: 39002813 DOI: 10.1016/j.tiv.2024.105893] [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: 04/13/2024] [Revised: 06/07/2024] [Accepted: 07/06/2024] [Indexed: 07/15/2024]
Abstract
BACKGROUND Polystyrene nanoplastics (PS-NPs), are ubiquitous pollution sources in human environments, posing significant biosafety and health risks. While recent studies, including our own, have illustrated that PS-NPs can breach the blood-testis barrier and impact germ cells, there remains a gap in understanding their effects on specific spermatogenic cells such as spermatocytes. METHODS AND RESULTS Herein, we employed an integrated approach encompassing phenotype, metabolomics, and transcriptomics analyses to assess the molecular impact of PS-NPs on mouse spermatocyte-derived GC-2spd(ts) cells. Optimal exposure conditions were determined as 24 h with 50 nm PS-NPs at 12.5 μg/mL and 90 nm PS-NPs at 50 μg/mL for subsequent multi-omics analysis. Our findings revealed that PS-NPs significantly influenced proliferation and viability, causing alterations in transcriptome and metabolome profiles. Transcriptomics analysis of GC-2spd(ts) cells exposed to PS-NPs indicated the pivotal involvement of cell proliferation and cycle, autophagy, ferroptosis, and redox reaction pathways in PS-NP-induced effects on the proliferation and viability of GC-2spd(ts) cells. Furthermore, metabolomics analysis identified major changes in amino acid metabolism, cyanoamino acid metabolism, and purine and pyrimidine metabolism following PS-NP exposure. CONCLUSION Our integrated approach, combining metabolomics and transcriptomics profiles with phenotype data, enhances our understanding of the adverse effects of PS-NPs on germ cells.
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Affiliation(s)
- Hang Han
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China; College of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Zhen Zhang
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Bo Xu
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Liyang Ding
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Hong Yang
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Tiantian He
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Xing Du
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Xiuying Pei
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China.
| | - Xufeng Fu
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China.
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Wu Y, Foollee A, Chan AY, Hille S, Hauke J, Challis MP, Johnson JL, Yaron TM, Mynard V, Aung OH, Cleofe MAS, Huang C, Lim Kam Sian TCC, Rahbari M, Gallage S, Heikenwalder M, Cantley LC, Schittenhelm RB, Formosa LE, Smith GC, Okun JG, Müller OJ, Rusu PM, Rose AJ. Phosphoproteomics-directed manipulation reveals SEC22B as a hepatocellular signaling node governing metabolic actions of glucagon. Nat Commun 2024; 15:8390. [PMID: 39333498 PMCID: PMC11436942 DOI: 10.1038/s41467-024-52703-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 09/16/2024] [Indexed: 09/29/2024] Open
Abstract
The peptide hormone glucagon is a fundamental metabolic regulator that is also being considered as a pharmacotherapeutic option for obesity and type 2 diabetes. Despite this, we know very little regarding how glucagon exerts its pleiotropic metabolic actions. Given that the liver is a chief site of action, we performed in situ time-resolved liver phosphoproteomics to reveal glucagon signaling nodes. Through pathway analysis of the thousands of phosphopeptides identified, we reveal "membrane trafficking" as a dominant signature with the vesicle trafficking protein SEC22 Homolog B (SEC22B) S137 phosphorylation being a top hit. Hepatocyte-specific loss- and gain-of-function experiments reveal that SEC22B was a key regulator of glycogen, lipid and amino acid metabolism, with SEC22B-S137 phosphorylation playing a major role in glucagon action. Mechanistically, we identify several protein binding partners of SEC22B affected by glucagon, some of which were differentially enriched with SEC22B-S137 phosphorylation. In summary, we demonstrate that phosphorylation of SEC22B is a hepatocellular signaling node mediating the metabolic actions of glucagon and provide a rich resource for future investigations on the biology of glucagon action.
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Affiliation(s)
- Yuqin Wu
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Ashish Foollee
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Andrea Y Chan
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Susanne Hille
- Department of Internal Medicine V, University Hospital of Schleswig-Holstein, Campus Kiel, Germany
- German Center for Cardiovascular Research (DZHK), Partner site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Jana Hauke
- Division of Inherited Metabolic Diseases, University Children's Hospital, Heidelberg, Germany
| | - Matthew P Challis
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Jared L Johnson
- Meyer Cancer Center, Weill Cornell Medicine, New York, USA
- Department of Cell Biology, Harvard Medical School, Boston, USA
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, USA
| | - Tomer M Yaron
- Meyer Cancer Center, Weill Cornell Medicine, New York, USA
- Englander Institute for Precision Medicine, Institute for Computational Biomedicine, Weill Cornell Medicine, New York, USA
- Columbia University Vagelos College of Physicians and Surgeons, New York, USA
| | - Victoria Mynard
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Okka H Aung
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Maria Almira S Cleofe
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Cheng Huang
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
- Monash Proteomics and Metabolomics Platform, Monash University, Victoria, Australia
| | | | - Mohammad Rahbari
- German Cancer Research Center (DKFZ), Division of Chronic Inflammation and Cancer, Im Neuenheimer Feld 280, Heidelberg, Germany
- University Hospital Mannheim, Medical Faculty Mannheim, University of Heidelberg, Department of Surgery, Theodor-Kutzer-Ufer 1-3, Heidelberg, Germany
- University Tuebingen, Faculty of Medicine, Institute for Interdisciplinary Research on Cancer Metabolism and Chronic Inflammation, M3-Research Center for Malignome, Metabolome and Microbiome, Otfried-Müller-Straße 37, Tübingen, Germany
| | - Suchira Gallage
- German Cancer Research Center (DKFZ), Division of Chronic Inflammation and Cancer, Im Neuenheimer Feld 280, Heidelberg, Germany
- University Tuebingen, Faculty of Medicine, Institute for Interdisciplinary Research on Cancer Metabolism and Chronic Inflammation, M3-Research Center for Malignome, Metabolome and Microbiome, Otfried-Müller-Straße 37, Tübingen, Germany
| | - Mathias Heikenwalder
- German Cancer Research Center (DKFZ), Division of Chronic Inflammation and Cancer, Im Neuenheimer Feld 280, Heidelberg, Germany
- University Tuebingen, Faculty of Medicine, Institute for Interdisciplinary Research on Cancer Metabolism and Chronic Inflammation, M3-Research Center for Malignome, Metabolome and Microbiome, Otfried-Müller-Straße 37, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard-Karls University, Tübingen, Germany
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medicine, New York, USA
- Department of Cell Biology, Harvard Medical School, Boston, USA
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, USA
| | - Ralf B Schittenhelm
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
- Monash Proteomics and Metabolomics Platform, Monash University, Victoria, Australia
| | - Luke E Formosa
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Greg C Smith
- School of Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Jürgen G Okun
- Division of Inherited Metabolic Diseases, University Children's Hospital, Heidelberg, Germany
| | - Oliver J Müller
- Department of Internal Medicine V, University Hospital of Schleswig-Holstein, Campus Kiel, Germany
- German Center for Cardiovascular Research (DZHK), Partner site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Patricia M Rusu
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia
| | - Adam J Rose
- Nutrient Metabolism & Signalling Laboratory, Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Victoria, Australia.
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Victoria, Australia.
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Knuth ER, Foster HR, Jin E, Ekstrand MH, Knudsen JG, Merrins MJ. Leucine Suppresses α-Cell cAMP and Glucagon Secretion via a Combination of Cell-Intrinsic and Islet Paracrine Signaling. Diabetes 2024; 73:1426-1439. [PMID: 38870025 PMCID: PMC11333377 DOI: 10.2337/db23-1013] [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: 12/19/2023] [Accepted: 06/10/2024] [Indexed: 06/15/2024]
Abstract
Glucagon is critical for the maintenance of blood glucose, however nutrient regulation of pancreatic α-cells remains poorly understood. Here, we identified a role of leucine, a well-known β-cell fuel, in the α-cell-intrinsic regulation of glucagon release. In islet perifusion assays, physiologic concentrations of leucine strongly inhibited alanine- and arginine-stimulated glucagon secretion from human and mouse islets under hypoglycemic conditions. Mechanistically, leucine dose-dependently reduced α-cell cAMP, independently of Ca2+, ATP/ADP, or fatty acid oxidation. Leucine also reduced α-cell cAMP in islets treated with somatostatin receptor 2 antagonists or diazoxide, compounds that limit paracrine signaling from β/δ-cells. Studies in dispersed mouse islets confirmed an α-cell-intrinsic effect. The inhibitory effect of leucine on cAMP was mimicked by glucose, α-ketoisocaproate, succinate, and the glutamate dehydrogenase activator BCH and blocked by cyanide, indicating a mechanism dependent on mitochondrial metabolism. Glucose dose-dependently reduced the impact of leucine on α-cell cAMP, indicating an overlap in function; however, leucine was still effective at suppressing glucagon secretion in the presence of elevated glucose, amino acids, and the incretin GIP. Taken together, these findings show that leucine plays an intrinsic role in limiting the α-cell secretory tone across the physiologic range of glucose levels, complementing the inhibitory paracrine actions of β/δ-cells. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Emily R. Knuth
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Hannah R. Foster
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Erli Jin
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Maia H. Ekstrand
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jakob G. Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Matthew J. Merrins
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Wisconsin-Madison, Madison, WI
- William S. Middleton Memorial Veterans Hospital, Madison, WI
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Xu Y, Liu Q, Chen CW, Wang Q, Du T, Yu R, Zhou Q, Yang D, Wang MW. Absence of PNET formation and normal longevity in a mouse model of Mahvash disease. Heliyon 2024; 10:e35362. [PMID: 39170309 PMCID: PMC11336617 DOI: 10.1016/j.heliyon.2024.e35362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2024] [Accepted: 07/26/2024] [Indexed: 08/23/2024] Open
Abstract
Mahvash disease, a rare autosomal recessive metabolic disorder characterized by biallelic loss-of-function mutations in the glucagon receptor gene (GCGR), induces significant pancreatic hyperglucagonemia, resulting in α-cell hyperplasia and occasional hypoglycemia. Utilizing CRISPR-Cas9 technology, we engineered a mouse model, designated as Gcgr V369M/V369M, harboring a homozygous V369M substitution in the glucagon receptor (GCGR). Although wild-type (WT) and Gcgr V369M/V369M mice exhibited no discernible difference in appearance or weight, adult Gcgr V369M/V369M mice, approximately 12 months of age, displayed a notable decrease in fasting blood glucose levels and elevated the levels of cholesterol and low-density lipoprotein-cholesterol. Moreover, plasma amino acid levels such as alanine (Ala), proline (Pro) and arginine (Arg) were elevated in Gcgr V369M/V369M mice contributing to α-cell proliferation and hyperglucagonemia. Despite sustained α-cell hyperplasia and increased circulating glucagon levels in Gcgr V369M/V369M mice, metabolic disparities between the two groups gradually waned with age accompanied by a reduction in α-cell hyperplasia. Throughout the lifespan of the mice (up to approximately 30 months), pancreatic neuroendocrine tumors (PNETs) did not manifest. This prolonged observation of metabolic alterations in Gcgr V369M/V369M mice furnishes valuable insights for a deeper comprehension of mild Mahvash disease in humans.
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Affiliation(s)
- Yingna Xu
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Qiaofeng Liu
- School of Pharmacy, Fudan University, Shanghai, 201203, China
| | - Chuan-Wei Chen
- Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China
| | - Qiuying Wang
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Tianyuan Du
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Run Yu
- Division of Endocrinology, Diabetes, and Metabolism, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Qingtong Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
- Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China
| | - Dehua Yang
- Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China
- State Key Laboratory of Chemical Biology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Ming-Wei Wang
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
- Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China
- Department of Chemistry, School of Science, The University of Tokyo, Tokyo, 113-0033, Japan
- Engineering Research Center of Tropical Medicine Innovation and Transformation of Ministry of Education, School of Pharmacy, Hainan Medical University, Haikou, 570228, China
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7
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Coate KC, Dai C, Singh A, Stanley J, Covington BA, Bradley A, Oladipupo F, Gong Y, Wisniewski S, Spears E, Poffenberger G, Bustabad A, Rodgers T, Dey N, Shultz LD, Greiner DL, Yan H, Powers AC, Chen W, Dean ED. Interruption of glucagon signaling augments islet non-alpha cell proliferation in SLC7A2- and mTOR-dependent manners. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.06.606926. [PMID: 39149351 PMCID: PMC11326219 DOI: 10.1101/2024.08.06.606926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Objective Dysregulated glucagon secretion and inadequate functional beta cell mass are hallmark features of diabetes. While glucagon receptor (GCGR) antagonism ameliorates hyperglycemia and elicits beta cell regeneration in pre-clinical models of diabetes, it also promotes alpha and delta cell hyperplasia. We sought to investigate the mechanism by which loss of glucagon action impacts pancreatic islet non-alpha cells, and the relevance of these observations in a human islet context. Methods We used zebrafish, rodents, and transplanted human islets comprising six different models of interrupted glucagon signaling to examine their impact on delta and beta cell proliferation and mass. We also used models with global deficiency of the cationic amino acid transporter, SLC7A2, and mTORC1 inhibition via rapamycin, to determine whether amino acid-dependent nutrient sensing was required for islet non-alpha cell growth. Results Inhibition of glucagon signaling stimulated delta cell proliferation in mouse and transplanted human islets, and in mouse islets. This was rapamycin-sensitive and required SLC7A2. Likewise, gcgr deficiency augmented beta cell proliferation via SLC7A2- and mTORC1-dependent mechanisms in zebrafish and promoted cell cycle engagement in rodent beta cells but was insufficient to drive a significant increase in beta cell mass in mice. Conclusion Our findings demonstrate that interruption of glucagon signaling augments islet non-alpha cell proliferation in zebrafish, rodents, and transplanted human islets in a manner requiring SLC7A2 and mTORC1 activation. An increase in delta cell mass may be leveraged for future beta cell regeneration therapies relying upon delta cell reprogramming.
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Affiliation(s)
- Katie C. Coate
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN
| | - Chunhua Dai
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Ajay Singh
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Jade Stanley
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Brittney A. Covington
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Amber Bradley
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Favour Oladipupo
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Yulong Gong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Scott Wisniewski
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Erick Spears
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Greg Poffenberger
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Alexandria Bustabad
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Tyler Rodgers
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Nandita Dey
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | | | - Dale L. Greiner
- Program in Molecular Medicine, Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA
| | - Hai Yan
- REMD Biotherapeutics Inc., Camarillo, CA
| | - Alvin C. Powers
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN
| | - Wenbiao Chen
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - E. Danielle Dean
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
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8
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Winther-Sørensen M, Garcia SL, Bartholdy A, Ottenheijm ME, Banasik K, Brunak S, Sørensen CM, Gluud LL, Knop FK, Holst JJ, Rosenkilde MM, Jensen MK, Wewer Albrechtsen NJ. Determinants of plasma levels of proglucagon and the metabolic impact of glucagon receptor signalling: a UK Biobank study. Diabetologia 2024; 67:1602-1615. [PMID: 38705923 PMCID: PMC11343844 DOI: 10.1007/s00125-024-06160-1] [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: 12/13/2023] [Accepted: 03/13/2024] [Indexed: 05/07/2024]
Abstract
AIMS/HYPOTHESES Glucagon and glucagon-like peptide-1 (GLP-1) are derived from the same precursor; proglucagon, and dual agonists of their receptors are currently being explored for the treatment of obesity and metabolic dysfunction-associated steatotic liver disease (MASLD). Elevated levels of endogenous glucagon (hyperglucagonaemia) have been linked with hyperglycaemia in individuals with type 2 diabetes but are also observed in individuals with obesity and MASLD. GLP-1 levels have been reported to be largely unaffected or even reduced in similar conditions. We investigated potential determinants of plasma proglucagon and associations of glucagon receptor signalling with metabolic diseases based on data from the UK Biobank. METHODS We used exome sequencing data from the UK Biobank for ~410,000 white participants to identify glucagon receptor variants and grouped them based on their known or predicted signalling. Data on plasma levels of proglucagon estimated using Olink technology were available for a subset of the cohort (~40,000). We determined associations of glucagon receptor variants and proglucagon with BMI, type 2 diabetes and liver fat (quantified by liver MRI) and performed survival analyses to investigate if elevated proglucagon predicts type 2 diabetes development. RESULTS Obesity, MASLD and type 2 diabetes were associated with elevated plasma levels of proglucagon independently of each other. Baseline proglucagon levels were associated with the risk of type 2 diabetes development over a 14 year follow-up period (HR 1.13; 95% CI 1.09, 1.17; n=1562; p=1.3×10-12). This association was of the same magnitude across strata of BMI. Carriers of glucagon receptor variants with reduced cAMP signalling had elevated levels of proglucagon (β 0.847; 95% CI 0.04, 1.66; n=17; p=0.04), and carriers of variants with a predicted frameshift mutation had higher levels of liver fat compared with the wild-type reference group (β 0.504; 95% CI 0.03, 0.98; n=11; p=0.04). CONCLUSIONS/INTERPRETATION Our findings support the suggestion that glucagon receptor signalling is involved in MASLD, that plasma levels of proglucagon are linked to the risk of type 2 diabetes development, and that proglucagon levels are influenced by genetic variation in the glucagon receptor, obesity, type 2 diabetes and MASLD. Determining the molecular signalling pathways downstream of glucagon receptor activation may guide the development of biased GLP-1/glucagon co-agonist with improved metabolic benefits. DATA AVAILABILITY All coding is available through https://github.com/nicwin98/UK-Biobank-GCG.
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Affiliation(s)
- Marie Winther-Sørensen
- Department for Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara L Garcia
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Bartholdy
- Section of Epidemiology, Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maud E Ottenheijm
- Department for Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karina Banasik
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Brunak
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte M Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lise Lotte Gluud
- Gastro Unit, Copenhagen University Hospital - Hvidovre, Hvidovre, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Herlev, Denmark
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, 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
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Majken K Jensen
- Section of Epidemiology, Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department for Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, University of Copenhagen, Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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9
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Kang Q, Jia J, Dean ED, Yuan H, Dai C, Li Z, Jiang F, Zhang XK, Powers AC, Chen W, Li M. ErbB3 is required for hyperaminoacidemia-induced pancreatic α cell hyperplasia. J Biol Chem 2024; 300:107499. [PMID: 38944125 PMCID: PMC11326907 DOI: 10.1016/j.jbc.2024.107499] [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: 03/14/2024] [Revised: 05/18/2024] [Accepted: 06/02/2024] [Indexed: 07/01/2024] Open
Abstract
Blood amino acid levels are maintained in a narrow physiological range. The pancreatic α cells have emerged as the primary aminoacidemia regulator through glucagon secretion to promote hepatic amino acid catabolism. Interruption of glucagon signaling disrupts the liver-α cells axis leading to hyperaminoacidemia, which triggers a compensatory rise in glucagon secretion and α cell hyperplasia. The mechanisms of hyperaminoacidemia-induced α cell hyperplasia remain incompletely understood. Using a mouse α cell line and in vivo studies in zebrafish and mice, we found that hyperaminoacidemia-induced α cell hyperplasia requires ErbB3 signaling. In addition to mechanistic target of rapamycin complex 1, another ErbB3 downstream effector signal transducer and activator of transcription 3 also plays a role in α cell hyperplasia. Mechanistically, ErbB3 may partner with ErbB2 to stimulate cyclin D2 and suppress p27 via mechanistic target of rapamycin complex 1 and signal transducer and activator of transcription 3. Our study identifies ErbB3 as a new regulator for hyperaminoacidemia-induced α cell proliferation and a critical component of the liver-α cells axis that regulates aminoacidemia.
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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
| | - 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
| | - E Danielle Dean
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Hang Yuan
- 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
| | - Chunhua Dai
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Zhehui 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
| | - Fuquan Jiang
- 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
| | - 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
| | - Alvin C Powers
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; VA Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Wenbiao Chen
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
| | - 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; State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, Xiamen University, Xiamen, China.
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10
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Merkhassine M, Coch RW, Frederick CE, Bennett LL, Peng SA, Morse B, Cummings BP, Loftus JP. Glucagon infusion alters the circulating metabolome and urine amino acid excretion in dogs. J Endocrinol 2024; 262:e240051. [PMID: 38814331 PMCID: PMC11301426 DOI: 10.1530/joe-24-0051] [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: 02/15/2024] [Accepted: 05/30/2024] [Indexed: 05/31/2024]
Abstract
Glucagon plays a central role in amino acid (AA) homeostasis. The dog is an established model of glucagon biology, and recently, metabolomic changes in people associated with glucagon infusions have been reported. Glucagon also has effects on the kidney; however, changes in urinary AA concentrations associated with glucagon remain under investigation. Therefore, we aimed to fill these gaps in the canine model by determining the effects of glucagon on the canine plasma metabolome and measuring urine AA concentrations. Employing two constant rate glucagon infusions (CRI) - low-dose (CRI-LO: 3 ng/kg/min) and high-dose (CRI-HI: 50 ng/kg/min) on five research beagles, we monitored interstitial glucose and conducted untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) on plasma samples and urine AA concentrations collected pre- and post-infusion. The CRI-HI induced a transient glucose peak (90-120 min), returning near baseline by infusion end, while only the CRI-LO resulted in 372 significantly altered plasma metabolites, primarily reductions (333). Similarly, CRI-HI affected 414 metabolites, with 369 reductions, evidenced by distinct clustering post-infusion via data reduction (PCA and sPLS-DA). CRI-HI notably decreased circulating AA levels, impacting various AA-related and energy-generating metabolic pathways. Urine analysis revealed increased 3-methyl-l-histidine and glutamine, and decreased alanine concentrations post-infusion. These findings demonstrate glucagon's glucose-independent modulation of the canine plasma metabolome and highlight the dog's relevance as a translational model for glucagon biology. Understanding these effects contributes to managing dysregulated glucagon conditions and informs treatments impacting glucagon homeostasis.
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Affiliation(s)
- Michael Merkhassine
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
- VCA Colonial Animal Hospital, Ithaca, New York, USA
| | - Reilly W Coch
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
- Weill Cornell College of Medicine, New York, New York, USA
| | - Carol E Frederick
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
| | - Lucinda L Bennett
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
| | - Seth A Peng
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
- Fate Therapeutics, San Diego, California, USA
| | - Benjamin Morse
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
| | - Bethany P Cummings
- Center for Alimentary and Metabolic Science, Department of Surgery, School of Medicine, University of California, Davis, Sacramento, California, USA
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - John P Loftus
- Loftus Laboratory, Department of Clinical Sciences, Cornell University, College of Veterinary Medicine, Ithaca, New York, USA
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11
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Gandasi NR, Rorsman P. An unclear role for the GLP-1 metabolite GLP-1(9-36) in human islet physiology. Reply to Matveyenko A, Vella A [letter]. Diabetologia 2024; 67:1446-1447. [PMID: 38578450 DOI: 10.1007/s00125-024-06140-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/06/2024]
Affiliation(s)
- Nikhil R Gandasi
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
- Cell Metabolism Lab (GA-08), Department of Developmental Biology and Genetics (DBG), Indian Institute of Science (IISc), Bangalore, India
| | - Patrik Rorsman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK.
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12
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Kajani S, Laker RC, Ratkova E, Will S, Rhodes CJ. Hepatic glucagon action: beyond glucose mobilization. Physiol Rev 2024; 104:1021-1060. [PMID: 38300523 DOI: 10.1152/physrev.00028.2023] [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: 07/11/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 02/02/2024] Open
Abstract
Glucagon's ability to promote hepatic glucose production has been known for over a century, with initial observations touting this hormone as a diabetogenic agent. However, glucagon receptor agonism [when balanced with an incretin, including glucagon-like peptide 1 (GLP-1) to dampen glucose excursions] is now being developed as a promising therapeutic target in the treatment of metabolic diseases, like metabolic dysfunction-associated steatotic disease/metabolic dysfunction-associated steatohepatitis (MASLD/MASH), and may also have benefit for obesity and chronic kidney disease. Conventionally regarded as the opposing tag-team partner of the anabolic mediator insulin, glucagon is gradually emerging as more than just a "catabolic hormone." Glucagon action on glucose homeostasis within the liver has been well characterized. However, growing evidence, in part thanks to new and sensitive "omics" technologies, has implicated glucagon as more than just a "glucose liberator." Elucidation of glucagon's capacity to increase fatty acid oxidation while attenuating endogenous lipid synthesis speaks to the dichotomous nature of the hormone. Furthermore, glucagon action is not limited to just glucose homeostasis and lipid metabolism, as traditionally reported. Glucagon plays key regulatory roles in hepatic amino acid and ketone body metabolism, as well as mitochondrial turnover and function, indicating broader glucagon signaling consequences for metabolic homeostasis mediated by the liver. Here we examine the broadening role of glucagon signaling within the hepatocyte and question the current dogma, to appreciate glucagon as more than just that "catabolic hormone."
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Affiliation(s)
- Sarina Kajani
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Rhianna C Laker
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Ekaterina Ratkova
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Mölndal, Sweden
| | - Sarah Will
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
| | - Christopher J Rhodes
- Early Cardiovascular, Renal and Metabolism, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, Maryland, United States
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13
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Hayashi Y. Advances in basic research on glucagon and alpha cells. Diabetol Int 2024; 15:348-352. [PMID: 39101161 PMCID: PMC11291817 DOI: 10.1007/s13340-024-00696-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 01/17/2024] [Indexed: 08/06/2024]
Abstract
The regulation of plasma amino acid levels by glucagon in humans first attracted the attention of researchers in the 1980s. Recent basic research using animal models of glucagon deficiency suggested that a major physiological role of glucagon is the regulation of amino acid metabolism rather than to increase blood glucose levels. In this regard, novel feedback regulatory mechanisms that are mediated by glucagon and amino acids have recently been described between islet alpha cells and the liver. Increasingly, hyperglucagonemia in humans with diabetes and/or nonalcoholic fatty liver diseases is reported to likely be a compensatory response to hepatic glucagon resistance. Severe glucagon resistance due to a glucagon receptor mutation in humans causes hyperaminoacidemia and islet alpha cell expansion combined with pancreatic hypertrophy. Notably, a recent report showed that the restoration of glucagon resistance by liver transplantation resolved not only hyperglucagonemia, but also pancreatic hypertrophy and other metabolic disorders. The mechanisms that regulate islet cell proliferation by amino acids largely remain unelucidated. Clarification of such mechanisms will increase our understanding of the pathophysiology of diseases related to glucagon.
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Affiliation(s)
- Yoshitaka Hayashi
- Department of Endocrinology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-Ku, Nagoya, 464-8601 Japan
- Department of Endocrinology, Nagoya University Graduate School of Medicine, Nagoya University, Nagoya, Japan
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14
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McGlone ER, Bloom SR, Tan TMM. Glucagon resistance and metabolic-associated steatotic liver disease: a review of the evidence. J Endocrinol 2024; 261:e230365. [PMID: 38579751 PMCID: PMC11067060 DOI: 10.1530/joe-23-0365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 04/03/2024] [Indexed: 04/07/2024]
Abstract
Metabolic-associated steatotic liver disease (MASLD) is closely associated with obesity. MASLD affects over 1 billion adults globally but there are few treatment options available. Glucagon is a key metabolic regulator, and its actions include the reduction of liver fat through direct and indirect means. Chronic glucagon signalling deficiency is associated with hyperaminoacidaemia, hyperglucagonaemia and increased circulating levels of glucagon-like peptide 1 (GLP-1) and fibroblast growth factor 21 (FGF-21). Reduction in glucagon activity decreases hepatic amino acid and triglyceride catabolism; metabolic effects include improved glucose tolerance, increased plasma cholesterol and increased liver fat. Conversely, glucagon infusion in healthy volunteers leads to increased hepatic glucose output, decreased levels of plasma amino acids and increased urea production, decreased plasma cholesterol and increased energy expenditure. Patients with MASLD share many hormonal and metabolic characteristics with models of glucagon signalling deficiency, suggesting that they could be resistant to glucagon. Although there are few studies of the effects of glucagon infusion in patients with obesity and/or MASLD, there is some evidence that the expected effect of glucagon on amino acid catabolism may be attenuated. Taken together, this evidence supports the notion that glucagon resistance exists in patients with MASLD and may contribute to the pathogenesis of MASLD. Further studies are warranted to investigate the direct effects of glucagon on metabolism in patients with MASLD.
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Affiliation(s)
- Emma Rose McGlone
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Tricia M-M Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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15
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Scoditti E, Sabatini S, Carli F, Gastaldelli A. Hepatic glucose metabolism in the steatotic liver. Nat Rev Gastroenterol Hepatol 2024; 21:319-334. [PMID: 38308003 DOI: 10.1038/s41575-023-00888-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/13/2023] [Indexed: 02/04/2024]
Abstract
The liver is central in regulating glucose homeostasis, being the major contributor to endogenous glucose production and the greatest reserve of glucose as glycogen. It is both a target and regulator of the action of glucoregulatory hormones. Hepatic metabolic functions are altered in and contribute to the highly prevalent steatotic liver disease (SLD), including metabolic dysfunction-associated SLD (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). In this Review, we describe the dysregulation of hepatic glucose metabolism in MASLD and MASH and associated metabolic comorbidities, and how advances in techniques and models for the assessment of hepatic glucose fluxes in vivo have led to the identification of the mechanisms related to the alterations in glucose metabolism in MASLD and comorbidities. These fluxes can ultimately increase hepatic glucose production concomitantly with fat accumulation and alterations in the secretion and action of glucoregulatory hormones. No pharmacological treatment has yet been approved for MASLD or MASH, but some antihyperglycaemic drugs approved for treating type 2 diabetes have shown positive effects on hepatic glucose metabolism and hepatosteatosis. A deep understanding of how MASLD affects glucose metabolic fluxes and glucoregulatory hormones might assist in the early identification of at-risk individuals and the use or development of targeted therapies.
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Affiliation(s)
- Egeria Scoditti
- Institute of Clinical Physiology, National Research Council, Lecce, Italy
| | - Silvia Sabatini
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Fabrizia Carli
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Amalia Gastaldelli
- Institute of Clinical Physiology, National Research Council, Pisa, Italy.
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16
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Coate KC, Ramnanan CJ, Smith M, Winnick JJ, Kraft G, Irimia-Dominguez J, Farmer B, Donahue EP, Roach PJ, Cherrington AD, Edgerton DS. Integration of metabolic flux with hepatic glucagon signaling and gene expression profiles in the conscious dog. Am J Physiol Endocrinol Metab 2024; 326:E428-E442. [PMID: 38324258 PMCID: PMC11193521 DOI: 10.1152/ajpendo.00316.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/08/2024]
Abstract
Glucagon rapidly and profoundly stimulates hepatic glucose production (HGP), but for reasons that are unclear, this effect normally wanes after a few hours, despite sustained plasma glucagon levels. This study characterized the time course of glucagon-mediated molecular events and their relevance to metabolic flux in the livers of conscious dogs. Glucagon was either infused into the hepato-portal vein at a sixfold basal rate in the presence of somatostatin and basal insulin, or it was maintained at a basal level in control studies. In one control group, glucose remained at basal, whereas in the other, glucose was infused to match the hyperglycemia that occurred in the hyperglucagonemic group. Elevated glucagon caused a rapid (30 min) and largely sustained increase in hepatic cAMP over 4 h, a continued elevation in glucose-6-phosphate (G6P), and activation and deactivation of glycogen phosphorylase and synthase activities, respectively. Net hepatic glycogenolysis increased rapidly, peaking at 15 min due to activation of the cAMP/PKA pathway, then slowly returned to baseline over the next 3 h in line with allosteric inhibition by glucose and G6P. Glucagon's stimulatory effect on HGP was sustained relative to the hyperglycemic control group due to continued PKA activation. Hepatic gluconeogenic flux did not increase due to the lack of glucagon's effect on substrate supply to the liver. Global gene expression profiling highlighted glucagon-regulated activation of genes involved in cellular respiration, metabolic processes, and signaling, as well as downregulation of genes involved in extracellular matrix assembly and development.NEW & NOTEWORTHY Glucagon rapidly stimulates hepatic glucose production, but these effects are transient. This study links the molecular and metabolic flux changes that occur in the liver over time in response to a rise in glucagon, demonstrating the strength of the dog as a translational model to couple findings in small animals and humans. In addition, this study clarifies why the rapid effects of glucagon on liver glycogen metabolism are not sustained.
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Affiliation(s)
- Katie C Coate
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Christopher J Ramnanan
- Department of Innovation in Medical Education, University of Ottawa Faculty of Medicine, Ottawa, Ontario, Canada
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Jason J Winnick
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Jose Irimia-Dominguez
- Department of Molecular and Cellular Endocrinology, Beckman Research Institute, Duarte, California, United States
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - E Patrick Donahue
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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17
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Suppli MP, Høgedal A, Bagger JI, Chabanova E, van Hall G, Forman JL, Christensen MB, Albrechtsen NJW, Holst JJ, Knop FK. Signs of Glucagon Resistance After a 2-Week Hypercaloric Diet Intervention. J Clin Endocrinol Metab 2024; 109:955-967. [PMID: 37967235 DOI: 10.1210/clinem/dgad666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/06/2023] [Accepted: 11/13/2023] [Indexed: 11/17/2023]
Abstract
CONTEXT Hyperglucagonemia is observed in individuals with obesity and contributes to the hyperglycemia of patients with type 2 diabetes. Hyperglucagonemia may develop due to steatosis-induced hepatic glucagon resistance resulting in impaired hepatic amino acid turnover and ensuing elevations of circulating glucagonotropic amino acids. OBJECTIVE We evaluated whether glucagon resistance could be induced in healthy individuals by a hypercaloric diet intervention designed to increase hepatic fat content. METHODS We recruited 20 healthy male individuals to follow a hypercaloric diet and a sedentary lifestyle for 2 weeks. Amino acid concentrations in response to infusion of glucagon were assessed during a pancreatic clamp with somatostatin and basal insulin. The reversibility of any metabolic changes was assessed 8 weeks after the intervention. Hepatic steatosis was assessed by magnetic resonance spectroscopy. RESULTS The intervention led to increased hepatic fat content (382% [206%; 705%], P < .01). Glucagon infusion led to a decrease in the concentration of total amino acids on all experimental days, but the percentage change in total amino acids was reduced (-2.5% ± 0.5% vs -0.2% ± 0.7%, P = .015) and the average slope of the decline in the total amino acid concentration was less steep (-2.0 ± 1.2 vs -1.2 ± 0.3 μM/min, P = .016) after the intervention compared to baseline. The changes were normalized at follow-up. CONCLUSION Our results indicate that short-term unhealthy behavior, which increases hepatic fat content, causes a reversible resistance to the effect of glucagon on amino acid concentrations in healthy individuals, which may explain the hyperglucagonemia associated with obesity and diabetes.
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Affiliation(s)
- Malte Palm Suppli
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
| | - Astrid Høgedal
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
| | - Jonatan Ising Bagger
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
- Steno Diabetes Center Copenhagen, DK-2730 Herlev, Denmark
| | - Elizaveta Chabanova
- Department of Radiology, Herlev Hospital, University of Copenhagen, DK-2730 Herlev, Denmark
| | - Gerrit van Hall
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Clinical Metabolomics Core Facility, Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Julie Lyng Forman
- Section of Biostatistics, Department of Public Health, University of Copenhagen, DK-1353 Copenhagen, Denmark
| | - Mikkel Bring Christensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark
- Copenhagen Center for Translational Research, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark
| | - Nicolai Jacob Wewer Albrechtsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Department of Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Filip Krag Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
- Steno Diabetes Center Copenhagen, DK-2730 Herlev, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
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18
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Wang MY, Zhang Z, Zhao S, Onodera T, Sun XN, Zhu Q, Li C, Li N, Chen S, Paredes M, Gautron L, Charron MJ, Marciano DK, Gordillo R, Drucker DJ, Scherer PE. Downregulation of the kidney glucagon receptor, essential for renal function and systemic homeostasis, contributes to chronic kidney disease. Cell Metab 2024; 36:575-597.e7. [PMID: 38237602 PMCID: PMC10932880 DOI: 10.1016/j.cmet.2023.12.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 09/10/2023] [Accepted: 12/19/2023] [Indexed: 02/12/2024]
Abstract
The glucagon receptor (GCGR) in the kidney is expressed in nephron tubules. In humans and animal models with chronic kidney disease, renal GCGR expression is reduced. However, the role of kidney GCGR in normal renal function and in disease development has not been addressed. Here, we examined its role by analyzing mice with constitutive or conditional kidney-specific loss of the Gcgr. Adult renal Gcgr knockout mice exhibit metabolic dysregulation and a functional impairment of the kidneys. These mice exhibit hyperaminoacidemia associated with reduced kidney glucose output, oxidative stress, enhanced inflammasome activity, and excess lipid accumulation in the kidney. Upon a lipid challenge, they display maladaptive responses with acute hypertriglyceridemia and chronic proinflammatory and profibrotic activation. In aged mice, kidney Gcgr ablation elicits widespread renal deposition of collagen and fibronectin, indicative of fibrosis. Taken together, our findings demonstrate an essential role of the renal GCGR in normal kidney metabolic and homeostatic functions. Importantly, mice deficient for kidney Gcgr recapitulate some of the key pathophysiological features of chronic kidney disease.
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Affiliation(s)
- May-Yun Wang
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zhuzhen Zhang
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shangang Zhao
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Sam and Ann Barshop Institute for Longevity and Aging Studies, Division of Endocrinology, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Toshiharu Onodera
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xue-Nan Sun
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Qingzhang Zhu
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chao Li
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Na Li
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shiuhwei Chen
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Megan Paredes
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Laurent Gautron
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maureen J Charron
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Denise K Marciano
- Division of Nephrology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ruth Gordillo
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Daniel J Drucker
- Lunenfeld-TanenbaumResearchInstitute, Mt. Sinai Hospital, Toronto, ON M5G1X5, Canada; Department of Medicine, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Philipp E Scherer
- Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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19
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Gandasi NR, Gao R, Kothegala L, Pearce A, Santos C, Acreman S, Basco D, Benrick A, Chibalina MV, Clark A, Guida C, Harris M, Johnson PRV, Knudsen JG, Ma J, Miranda C, Shigeto M, Tarasov AI, Yeung HY, Thorens B, Asterholm IW, Zhang Q, Ramracheya R, Ladds G, Rorsman P. GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of mouse and human pancreatic islet glucagon secretion. Diabetologia 2024; 67:528-546. [PMID: 38127123 PMCID: PMC10844371 DOI: 10.1007/s00125-023-06060-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 10/18/2023] [Indexed: 12/23/2023]
Abstract
AIMS/HYPOTHESIS Diabetes mellitus is associated with impaired insulin secretion, often aggravated by oversecretion of glucagon. Therapeutic interventions should ideally correct both defects. Glucagon-like peptide 1 (GLP-1) has this capability but exactly how it exerts its glucagonostatic effect remains obscure. Following its release GLP-1 is rapidly degraded from GLP-1(7-36) to GLP-1(9-36). We hypothesised that the metabolite GLP-1(9-36) (previously believed to be biologically inactive) exerts a direct inhibitory effect on glucagon secretion and that this mechanism becomes impaired in diabetes. METHODS We used a combination of glucagon secretion measurements in mouse and human islets (including islets from donors with type 2 diabetes), total internal reflection fluorescence microscopy imaging of secretory granule dynamics, recordings of cytoplasmic Ca2+ and measurements of protein kinase A activity, immunocytochemistry, in vivo physiology and GTP-binding protein dissociation studies to explore how GLP-1 exerts its inhibitory effect on glucagon secretion and the role of the metabolite GLP-1(9-36). RESULTS GLP-1(7-36) inhibited glucagon secretion in isolated islets with an IC50 of 2.5 pmol/l. The effect was particularly strong at low glucose concentrations. The degradation product GLP-1(9-36) shared this capacity. GLP-1(9-36) retained its glucagonostatic effects after genetic/pharmacological inactivation of the GLP-1 receptor. GLP-1(9-36) also potently inhibited glucagon secretion evoked by β-adrenergic stimulation, amino acids and membrane depolarisation. In islet alpha cells, GLP-1(9-36) led to inhibition of Ca2+ entry via voltage-gated Ca2+ channels sensitive to ω-agatoxin, with consequential pertussis-toxin-sensitive depletion of the docked pool of secretory granules, effects that were prevented by the glucagon receptor antagonists REMD2.59 and L-168049. The capacity of GLP-1(9-36) to inhibit glucagon secretion and reduce the number of docked granules was lost in alpha cells from human donors with type 2 diabetes. In vivo, high exogenous concentrations of GLP-1(9-36) (>100 pmol/l) resulted in a small (30%) lowering of circulating glucagon during insulin-induced hypoglycaemia. This effect was abolished by REMD2.59, which promptly increased circulating glucagon by >225% (adjusted for the change in plasma glucose) without affecting pancreatic glucagon content. CONCLUSIONS/INTERPRETATION We conclude that the GLP-1 metabolite GLP-1(9-36) is a systemic inhibitor of glucagon secretion. We propose that the increase in circulating glucagon observed following genetic/pharmacological inactivation of glucagon signalling in mice and in people with type 2 diabetes reflects the removal of GLP-1(9-36)'s glucagonostatic action.
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Affiliation(s)
- Nikhil R Gandasi
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Cell Metabolism Lab (GA-08), Department of Developmental Biology and Genetics, Indian Institute of Science, Bangalore, India
| | - Rui Gao
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Lakshmi Kothegala
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Abigail Pearce
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Cristiano Santos
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Samuel Acreman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Davide Basco
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Anna Benrick
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Margarita V Chibalina
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Matthew Harris
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Paul R V Johnson
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, Oxford, UK
- Biomedical Research Centre, Oxford National Institute for Health Research, Churchill Hospital, Oxford, UK
| | - Jakob G Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jinfang Ma
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Caroline Miranda
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Makoto Shigeto
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Andrei I Tarasov
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Ho Yan Yeung
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ingrid W Asterholm
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Reshma Ramracheya
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Graham Ladds
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Patrik Rorsman
- Metabolic Physiology Unit, Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden.
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK.
- Biomedical Research Centre, Oxford National Institute for Health Research, Churchill Hospital, Oxford, UK.
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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20
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Yang Y, Wang S, Sheng C, Tan J, Chen J, Li T, Ma X, Sun H, Wang X, Zhou L. Branched-chain amino acid catabolic defect promotes α-cell proliferation via activating mTOR signaling. Mol Cell Endocrinol 2024; 582:112143. [PMID: 38158148 DOI: 10.1016/j.mce.2023.112143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/09/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Elevated circulating level of branched-chain amino acids (BCAAs) is closely related to the development of type 2 diabetes. However, the role of BCAA catabolism in various tissues in maintaining glucose homeostasis remains largely unknown. Pancreatic α-cells have been regarded as amino acid sensors in recent years. Therefore, we generated α-cell specific branched-chain alpha-ketoacid dehydrogenase E1α subunit (BCKDHA) knockout (BCKDHA-αKO) mice to decipher the effects of BCAA catabolism in α-cells on whole-body energy metabolism. BCKDHA-αKO mice showed normal body weight, body fat, and energy expenditure. Plasma glucagon level and glucose metabolism also remained unchanged in BCKDHA-αKO mice. Whereas, the deletion of BCKDHA led to increased α-cell number due to elevated cell proliferation in neonatal mice. In vitro, only leucine among BCAAs promoted aTC1-6 cell proliferation, which was blocked by the agonist of BCAA catabolism BT2 and the inhibitor of mTOR Rapamycin. Like Rapamycin, BT2 attenuated leucine-stimulated phosphorylation of S6 in αTC1-6 cells. Elevated phosphorylation level of S6 protein in pancreatic α-cells was also observed in BCKDHA-αKO mice. These results suggest that local accumulated leucine due to defective BCAA catabolism promotes α-cell proliferation through mTOR signaling, which is insufficient to affect glucagon secretion and whole-body glucose homeostasis.
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Affiliation(s)
- Yulin Yang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shushu Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chunxiang Sheng
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jialin Tan
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Junmin Chen
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Academy of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Tianjiao Li
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoqin Ma
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haipeng Sun
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Center for Cardiovascular Diseases, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, 300134, China
| | - Xiao Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Libin Zhou
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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21
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Xia R, Peng HF, Zhang X, Zhang HS. Comprehensive review of amino acid transporters as therapeutic targets. Int J Biol Macromol 2024; 260:129646. [PMID: 38272411 DOI: 10.1016/j.ijbiomac.2024.129646] [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: 11/24/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
The solute carrier (SLC) family, with more than 400 membrane-bound proteins, facilitates the transport of a wide array of substrates such as nutrients, ions, metabolites, and drugs across biological membranes. Amino acid transporters (AATs) are membrane transport proteins that mediate transfer of amino acids into and out of cells or cellular organelles. AATs participate in many important physiological functions including nutrient supply, metabolic transformation, energy homeostasis, redox regulation, and neurological regulation. Several AATs have been found to significantly impact the progression of human malignancies, and dysregulation of AATs results in metabolic reprogramming affecting tumor growth and progression. However, current clinical therapies that directly target AATs have not been developed. The purpose of this review is to highlight the structural and functional diversity of AATs, the molecular mechanisms in human diseases such as tumors, kidney diseases, and emerging therapeutic strategies for targeting AATs.
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Affiliation(s)
- Ran Xia
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China
| | - Hai-Feng Peng
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China
| | - Xing Zhang
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China
| | - Hong-Sheng Zhang
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China.
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22
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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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23
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Rix I, Johansen ML, Lund A, Suppli MP, Chabanova E, van Hall G, Holst JJ, Wewer Albrechtsen NJ, Kistorp C, Knop FK. Hyperglucagonaemia and amino acid alterations in individuals with type 2 diabetes and non-alcoholic fatty liver disease. Endocr Connect 2024; 13:e230161. [PMID: 37947763 PMCID: PMC10762555 DOI: 10.1530/ec-23-0161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 11/10/2023] [Indexed: 11/12/2023]
Abstract
Aims Hyperglucagonaemia contributes to the pathophysiology in type 2 diabetes (T2D), but the mechanisms behind the inappropriate glucagon secretion are not fully understood. Glucagon and amino acids are regulated in a feedback loop referred to as the liver-α cell axis. Individuals with non-alcoholic fatty liver disease (NAFLD) appear to be glucagon resistant, disrupting the liver-α cell axis resulting in hyperglucagonaemia and hyperaminoacidaemia. We investigated the associations between circulating glucagon, amino acids, and liver fat content in a cohort of individuals with T2D. Methods We included 110 individuals with T2D in this cross-sectional study. Liver fat content was quantified using 1H magnetic resonance spectroscopy (MRS). Associations between liver fat content and plasma glucagon and amino acids, respectively, were estimated in multivariate linear regression analyses. Results Individuals with NAFLD (n = 52) had higher plasma glucagon concentrations than individuals without NAFLD (n = 58). The positive association between plasma glucagon concentrations and liver fat content was confirmed in the multivariable regression analyses. Plasma concentrations of isoleucine and glutamate were increased, and glycine and serine concentrations were decreased in individuals with NAFLD. Concentrations of other amino acids were similar between individuals with and without NAFLD, and no clear association was seen between liver fat content and amino acids in the regression analyses. Conclusion MRS-diagnosed NAFLD in T2D is associated with hyperglucagonaemia and elevated plasma concentrations of isoleucine and glutamate and low plasma concentrations of glycine and serine. Whether NAFLD and glucagon resistance per se induce these changes remains to be elucidated.
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Affiliation(s)
- Iben Rix
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Zealand Pharma A/S, Søborg, Denmark
| | - Marie L Johansen
- Department of Medicine, Herlev Hospital, University of Copenhagen, Herlev, Denmark
| | - Asger Lund
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Malte P Suppli
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Elizaveta Chabanova
- Department of Radiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark
| | - Gerrit van Hall
- Clinical Metabolomics Core Facility, 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
| | - 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
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline Kistorp
- Department of Endocrinology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Herlev, Denmark
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Guo X, Liang K, Xia L, Zhang X, Liu J, Wang C, Li J, Li X, Hou X, Chen L. Mof plays distinct roles in hepatic lipid metabolism under healthy or non-alcoholic fatty liver conditions. iScience 2023; 26:108446. [PMID: 38034359 PMCID: PMC10687339 DOI: 10.1016/j.isci.2023.108446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 09/11/2023] [Accepted: 11/09/2023] [Indexed: 12/02/2023] Open
Abstract
The disturbance of hepatic lipid metabolism has a strong association with non-alcoholic fatty liver disease (NAFLD) and diabetes. Mof, an acetyltransferase involved in obesity and carbon metabolism, has not been thoroughly examined in its connection to hepatic metabolism. We aimed to explore the impact of Mof on hepatic lipid metabolism. The alteration of Mof expression was found in both obese mice and NAFLD human liver. The genes regulated by Mof were closely associated with lipid metabolism. In normal mice or hepatic cells, the down-regulation or inhibition of Mof resulted in increased lipid accumulation due to decreased PPARα expression. Conversely, in diet-induced obesity (DIO) mice or hepatic cells treated with palmitic acid, the inhibition of Mof led to improved lipid metabolism, attributed to the reduction in p-mTOR/mTOR levels. In summary, Mof exhibited distinct roles in lipid metabolism under different conditions. The inhibition of Mof may hold potential as a therapeutic target for hepatic lipid metabolism disturbances.
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Affiliation(s)
- Xinghong Guo
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
| | - Kai Liang
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
| | - Longqing Xia
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Xu Zhang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Life Science School of Shandong University, Qingdao, Shandong 266237, China
| | - Jinbo Liu
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
| | - Chuan Wang
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
| | - Jinquan Li
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
| | - Xiangzhi Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Life Science School of Shandong University, Qingdao, Shandong 266237, China
| | - Xinguo Hou
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
| | - Li Chen
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, Shandong 250012, China
- Key Laboratory of Endocrine and Metabolic Diseases, Shandong Province Medicine & Health, Jinan, Shandong 250012, China
- Jinan Clinical Research Center for Endocrine and Metabolic Disease, Jinan, Shandong 250012, China
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Ferreira B, Heredia A, Serpa J. An integrative view on glucagon function and putative role in the progression of pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC). Mol Cell Endocrinol 2023; 578:112063. [PMID: 37678603 DOI: 10.1016/j.mce.2023.112063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/16/2023] [Accepted: 09/02/2023] [Indexed: 09/09/2023]
Abstract
Cancer metabolism research area evolved greatly, however, is still unknown the impact of systemic metabolism control and diet on cancer. It makes sense that systemic regulators of metabolism can act directly on cancer cells and activate signalling, prompting metabolic remodelling needed to sustain cancer cell survival, tumour growth and disease progression. In the present review, we describe the main glucagon functions in the control of glycaemia and of metabolic pathways overall. Furthermore, an integrative view on how glucagon and related signalling pathways can contribute for pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC) progression, since pancreas and liver are the major organs exposed to higher levels of glucagon, pancreas as a producer and liver as a scavenger. The main objective is to bring to discussion some glucagon-dependent mechanisms by presenting an integrative view on microenvironmental and systemic aspects in pNETs and HCC biology.
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Affiliation(s)
- Bárbara Ferreira
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal
| | - Adrián Heredia
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal; Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz MB, 1649-028, Lisboa, Portugal
| | - Jacinta Serpa
- iNOVA4Health, NOVA Medical School, Faculdade de Ciências Médicas, NMS, FCM, Universidade NOVA de Lisboa, Campo Dos Mártires da Pátria, 130, 1169-056, Lisboa, Portugal; Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Rua Prof Lima Basto, 1099-023, Lisboa, Portugal.
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Welch AA, Farahani RA, Egan AM, Laurenti MC, Zeini M, Vella M, Bailey KR, Cobelli C, Dalla Man C, Matveyenko A, Vella A. Glucagon-like peptide-1 receptor blockade impairs islet secretion and glucose metabolism in humans. J Clin Invest 2023; 133:e173495. [PMID: 37751301 PMCID: PMC10645389 DOI: 10.1172/jci173495] [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: 07/07/2023] [Accepted: 09/12/2023] [Indexed: 09/27/2023] Open
Abstract
BACKGROUNDProglucagon can be processed to glucagon-like peptide1 (GLP-1) within the islet, but its contribution to islet function in humans remains unknown. We sought to understand whether pancreatic GLP-1 alters islet function in humans and whether this is affected by type 2 diabetes.METHODSWe therefore studied individuals with and without type 2 diabetes on two occasions in random order. On one occasion, exendin 9-39, a competitive antagonist of the GLP-1 Receptor (GLP1R), was infused, while on the other, saline was infused. The tracer dilution technique ([3-3H] glucose) was used to measure glucose turnover during fasting and during a hyperglycemic clamp.RESULTSExendin 9-39 increased fasting glucose concentrations; fasting islet hormone concentrations were unchanged, but inappropriate for the higher fasting glucose observed. In people with type 2 diabetes, fasting glucagon concentrations were markedly elevated and persisted despite hyperglycemia. This impaired suppression of endogenous glucose production by hyperglycemia.CONCLUSIONThese data show that GLP1R blockade impairs islet function, implying that intra-islet GLP1R activation alters islet responses to glucose and does so to a greater degree in people with type 2 diabetes.TRIAL REGISTRATIONThis study was registered at ClinicalTrials.gov NCT04466618.FUNDINGThe study was primarily funded by NIH NIDDK DK126206. AV is supported by DK78646, DK116231 and DK126206. CDM was supported by MIUR (Italian Minister for Education) under the initiative "Departments of Excellence" (Law 232/2016).
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Affiliation(s)
- Andrew A. Welch
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Rahele A. Farahani
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Aoife M. Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Marcello C. Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Maya Zeini
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Max Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Kent R. Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Aleksey Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Zhang Y, Fang XM. The pan-liver network theory: From traditional chinese medicine to western medicine. CHINESE J PHYSIOL 2023; 66:401-436. [PMID: 38149555 DOI: 10.4103/cjop.cjop-d-22-00131] [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] [Indexed: 12/28/2023] Open
Abstract
In traditional Chinese medicine (TCM), the liver is the "general organ" that is responsible for governing/maintaining the free flow of qi over the entire body and storing blood. According to the classic five elements theory, zang-xiang theory, yin-yang theory, meridians and collaterals theory, and the five-viscera correlation theory, the liver has essential relationships with many extrahepatic organs or tissues, such as the mother-child relationships between the liver and the heart, and the yin-yang and exterior-interior relationships between the liver and the gallbladder. The influences of the liver to the extrahepatic organs or tissues have been well-established when treating the extrahepatic diseases from the perspective of modulating the liver by using the ancient classic prescriptions of TCM and the acupuncture and moxibustion. In modern medicine, as the largest solid organ in the human body, the liver has the typical functions of filtration and storage of blood; metabolism of carbohydrates, fats, proteins, hormones, and foreign chemicals; formation of bile; storage of vitamins and iron; and formation of coagulation factors. The liver also has essential endocrine function, and acts as an immunological organ due to containing the resident immune cells. In the perspective of modern human anatomy, physiology, and pathophysiology, the liver has the organ interactions with the extrahepatic organs or tissues, for example, the gut, pancreas, adipose, skeletal muscle, heart, lung, kidney, brain, spleen, eyes, skin, bone, and sexual organs, through the circulation (including hemodynamics, redox signals, hepatokines, metabolites, and the translocation of microbiota or its products, such as endotoxins), the neural signals, or other forms of pathogenic factors, under normal or diseases status. The organ interactions centered on the liver not only influence the homeostasis of these indicated organs or tissues, but also contribute to the pathogenesis of cardiometabolic diseases (including obesity, type 2 diabetes mellitus, metabolic [dysfunction]-associated fatty liver diseases, and cardio-cerebrovascular diseases), pulmonary diseases, hyperuricemia and gout, chronic kidney disease, and male and female sexual dysfunction. Therefore, based on TCM and modern medicine, the liver has the bidirectional interaction with the extrahepatic organ or tissue, and this established bidirectional interaction system may further interact with another one or more extrahepatic organs/tissues, thus depicting a complex "pan-hepatic network" model. The pan-hepatic network acts as one of the essential mechanisms of homeostasis and the pathogenesis of diseases.
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Affiliation(s)
- Yaxing Zhang
- Department of Physiology; Research Centre of Basic Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong; Issue 12th of Guangxi Apprenticeship Education of Traditional Chinese Medicine (Shi-Cheng Class of Guangxi University of Chinese Medicine), College of Continuing Education, Guangxi University of Chinese Medicine, Nanning, Guangxi, China
| | - Xian-Ming Fang
- Department of Cardiology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine (Guangxi Hospital of Integrated Chinese Medicine and Western Medicine, Ruikang Clinical Faculty of Guangxi University of Chinese Medicine), Guangxi University of Chinese Medicine, Nanning, Guangxi, China
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Coate KC, Ramnanan CJ, Smith M, Winnick JJ, Kraft G, Irimia JM, Farmer B, Donahue P, Roach PJ, Cherrington AD, Edgerton DS. Integration of metabolic flux with hepatic glucagon signaling and gene expression profiles in the conscious dog. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.28.559999. [PMID: 37808670 PMCID: PMC10557670 DOI: 10.1101/2023.09.28.559999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Glucagon rapidly and profoundly simulates hepatic glucose production (HGP), but for reasons which are unclear, this effect normally wanes after a few hours, despite sustained plasma glucagon levels. This study characterized the time course and relevance (to metabolic flux) of glucagon mediated molecular events in the livers of conscious dogs. Glucagon was either infused into the hepato-portal vein at a 6-fold basal rate in the presence of somatostatin and basal insulin, or it was maintained at a basal level in control studies. In one control group glucose remained at basal while in the other glucose was infused to match the hyperglycemia that occurred in the hyperglucagonemic group. Elevated glucagon caused a rapid (30 min) but only partially sustained increase in hepatic cAMP over 4h, a continued elevation in G6P, and activation and deactivation of glycogen phosphorylase and synthase activities, respectively. Net hepatic glycogenolysis and HGP increased rapidly, peaking at 30 min, then returned to baseline over the next 3h (although glucagons stimulatory effect on HGP was sustained relative to the hyperglycemic control group). Hepatic gluconeogenic flux did not increase due to lack of glucagon effect on substrate supply to the liver. Global gene expression profiling highlighted glucagon-regulated activation of genes involved in cellular respiration, metabolic processes, and signaling, and downregulation of genes involved in extracellular matrix assembly and development.
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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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Zhang J, Zheng Y, Martens L, Pfeiffer AFH. The Regulation and Secretion of Glucagon in Response to Nutrient Composition: Unraveling Their Intricate Mechanisms. Nutrients 2023; 15:3913. [PMID: 37764697 PMCID: PMC10536047 DOI: 10.3390/nu15183913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Glucagon was initially regarded as a hyperglycemic substance; however, recent research has revealed its broader role in metabolism, encompassing effects on glucose, amino acids (AAs), and lipid metabolism. Notably, the interplay of glucagon with nutrient intake, particularly of AAs, and non-nutrient components is central to its secretion. Fasting and postprandial hyperglucagonemia have long been linked to the development and progression of type 2 diabetes (T2DM). However, recent studies have brought to light the positive impact of glucagon agonists on lipid metabolism and energy homeostasis. This review explores the multifaceted actions of glucagon, focusing on its regulation, signaling pathways, and effects on glucose, AAs, and lipid metabolism. The interplay between glucagon and other hormones, including insulin and incretins, is examined to provide a mechanistic understanding of its functions. Notably, the liver-α-cell axis, which involves glucagon and amino acids, emerges as a critical aspect of metabolic regulation. The dysregulation of glucagon secretion and its impact on conditions such as T2DM are discussed. The review highlights the potential therapeutic applications of targeting the glucagon pathway in the treatment of metabolic disorders.
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Affiliation(s)
- Jiudan Zhang
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
| | - Yang Zheng
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
| | - Lisa Martens
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
- Nutritional Science, University of Potsdam, 14469 Potsdam, Germany
| | - Andreas F. H. Pfeiffer
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
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Ueno S, Seino Y, Hidaka S, Nakatani M, Hitachi K, Murao N, Maeda Y, Fujisawa H, Shibata M, Takayanagi T, Iizuka K, Yabe D, Sugimura Y, Tsuchida K, Hayashi Y, Suzuki A. Blockade of glucagon increases muscle mass and alters fiber type composition in mice deficient in proglucagon-derived peptides. J Diabetes Investig 2023; 14:1045-1055. [PMID: 37300240 PMCID: PMC10445200 DOI: 10.1111/jdi.14032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/02/2023] [Accepted: 05/12/2023] [Indexed: 06/12/2023] Open
Abstract
AIMS/INTRODUCTION Glucagon is secreted from pancreatic α-cells and plays an important role in amino acid metabolism in liver. Various animal models deficient in glucagon action show hyper-amino acidemia and α-cell hyperplasia, indicating that glucagon contributes to feedback regulation between the liver and the α-cells. In addition, both insulin and various amino acids, including branched-chain amino acids and alanine, participate in protein synthesis in skeletal muscle. However, the effect of hyperaminoacidemia on skeletal muscle has not been investigated. In the present study, we examined the effect of blockade of glucagon action on skeletal muscle using mice deficient in proglucagon-derived peptides (GCGKO mice). MATERIALS AND METHODS Muscles isolated from GCGKO and control mice were analyzed for their morphology, gene expression and metabolites. RESULTS GCGKO mice showed muscle fiber hypertrophy, and a decreased ratio of type IIA and an increased ratio of type IIB fibers in the tibialis anterior. The expression levels of myosin heavy chain (Myh) 7, 2, 1 and myoglobin messenger ribonucleic acid were significantly lower in GCGKO mice than those in control mice in the tibialis anterior. GCGKO mice showed a significantly higher concentration of arginine, asparagine, serine and threonine in the quadriceps femoris muscles, and also alanine, aspartic acid, cysteine, glutamine, glycine and lysine, as well as four amino acids in gastrocnemius muscles. CONCLUSIONS These results show that hyperaminoacidemia induced by blockade of glucagon action in mice increases skeletal muscle weight and stimulates slow-to-fast transition in type II fibers of skeletal muscle, mimicking the phenotype of a high-protein diet.
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Affiliation(s)
- Shinji Ueno
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
| | - Yusuke Seino
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
- Yutaka Seino Distinguished Center for Diabetes ResearchKansai Electric Power Medical Research InstituteKyotoKyotoJapan
| | - Shihomi Hidaka
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
| | - Masashi Nakatani
- Faculty of RehabilitationSeijoh UniversityTokaiAichiJapan
- Institute for Comprehensive Medical ScienceFujita Health UniversityToyoakeAichiJapan
| | - Keisuke Hitachi
- Institute for Comprehensive Medical ScienceFujita Health UniversityToyoakeAichiJapan
| | - Naoya Murao
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
- Yutaka Seino Distinguished Center for Diabetes ResearchKansai Electric Power Medical Research InstituteKyotoKyotoJapan
| | - Yasuhiro Maeda
- Open Facility CenterFujita Health UniversityToyoakeAichiJapan
| | - Haruki Fujisawa
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
| | - Megumi Shibata
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
| | - Takeshi Takayanagi
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
| | - Katsumi Iizuka
- Department of Clinical NutritionFujita Health UniversityToyoakeAichiJapan
| | - Daisuke Yabe
- Yutaka Seino Distinguished Center for Diabetes ResearchKansai Electric Power Medical Research InstituteKyotoKyotoJapan
- Department of Diabetes, Endocrinology and MetabolismGifu University Graduate School of MedicineGifuGifuJapan
- Department of Rheumatology and Clinical ImmunologyGifu University Graduate School of MedicineGifuGifuJapan
- Center for One Medicine Innovative Translational ResearchGifu University Graduate School of MedicineGifuGifuJapan
- Center for Healthcare Information TechnologyTokai National Higher Education and Research SystemNagoyaAichiJapan
- Division of Molecular and Metabolic MedicineKobe University Graduate School of MedicineKobeHyogoJapan
| | - Yoshihisa Sugimura
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
| | - Kunihiro Tsuchida
- Institute for Comprehensive Medical ScienceFujita Health UniversityToyoakeAichiJapan
| | - Yoshitaka Hayashi
- Department of Endocrinology, Research Institute of Environmental MedicineNagoya UniversityNagoyaAichiJapan
- Department of EndocrinologyNagoya University Graduate School of MedicineNagoyaAichiJapan
| | - Atsushi Suzuki
- Departments of Endocrinology, Diabetes and MetabolismFujita Health University School of MedicineToyoakeAichiJapan
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Armour SL, Stanley JE, Cantley J, Dean ED, Knudsen JG. Metabolic regulation of glucagon secretion. J Endocrinol 2023; 259:e230081. [PMID: 37523232 PMCID: PMC10681275 DOI: 10.1530/joe-23-0081] [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: 03/17/2023] [Accepted: 07/31/2023] [Indexed: 08/01/2023]
Abstract
Since the discovery of glucagon 100 years ago, the hormone and the pancreatic islet alpha cells that produce it have remained enigmatic relative to insulin-producing beta cells. Canonically, alpha cells have been described in the context of glucagon's role in glucose metabolism in liver, with glucose as the primary nutrient signal regulating alpha cell function. However, current data reveal a more holistic model of metabolic signalling, involving glucagon-regulated metabolism of multiple nutrients by the liver and other tissues, including amino acids and lipids, providing reciprocal feedback to regulate glucagon secretion and even alpha cell mass. Here we describe how various nutrients are sensed, transported and metabolised in alpha cells, providing an integrative model for the metabolic regulation of glucagon secretion and action. Importantly, we discuss where these nutrient-sensing pathways intersect to regulate alpha cell function and highlight key areas for future research.
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Affiliation(s)
- Sarah L Armour
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, DK
| | - Jade E. Stanley
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, USA
| | - James Cantley
- Division of Cellular and systems medicine, School of Medicine, University of Dundee, UK
| | - E. Danielle Dean
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, USA
- Division of Diabetes, Endocrinology, & Metabolism, Vanderbilt University Medical Center school of medicine, USA
| | - Jakob G Knudsen
- Section for cell biology and physiology, Department of Biology, University of Copenhagen, DK
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Knuth ER, Foster HR, Jin E, Merrins MJ. Leucine suppresses glucagon secretion from pancreatic islets by directly modulating α-cell cAMP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.31.551113. [PMID: 37577685 PMCID: PMC10418066 DOI: 10.1101/2023.07.31.551113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Objective Pancreatic islets are nutrient sensors that regulate organismal blood glucose homeostasis. Glucagon release from the pancreatic α-cell is important under fasted, fed, and hypoglycemic conditions, yet metabolic regulation of α-cells remains poorly understood. Here, we identified a previously unexplored role for physiological levels of leucine, which is classically regarded as a β-cell fuel, in the intrinsic regulation of α-cell glucagon release. Methods GcgCreERT:CAMPER and GcgCreERT:GCaMP6s mice were generated to perform dynamic, high-throughput functional measurements of α-cell cAMP and Ca2+ within the intact islet. Islet perifusion assays were used for simultaneous, time-resolved measurements of glucagon and insulin release from mouse and human islets. The effects of leucine were compared with glucose and the mitochondrial fuels 2-aminobicyclo(2,2,1)heptane-2-carboxylic acid (BCH, non-metabolized leucine analog that activates glutamate dehydrogenase), α-ketoisocaproate (KIC, leucine metabolite), and methyl-succinate (complex II fuel). CYN154806 (Sstr2 antagonist), diazoxide (KATP activator, which prevents Ca2+-dependent exocytosis from α, β, and δ-cells), and dispersed α-cells were used to inhibit islet paracrine signaling and identify α-cell intrinsic effects. Results Mimicking the effect of glucose, leucine strongly suppressed amino acid-stimulated glucagon secretion. Mechanistically, leucine dose-dependently reduced α-cell cAMP at physiological concentrations, with an IC50 of 57, 440, and 1162 μM at 2, 6, and 10 mM glucose, without affecting α-cell Ca2+. Leucine also reduced α-cell cAMP in islets treated with Sstr2 antagonist or diazoxide, as well as dispersed α-cells, indicating an α-cell intrinsic effect. The effect of leucine was matched by KIC and the glutamate dehydrogenase activator BCH, but not methyl-succinate, indicating a dependence on mitochondrial anaplerosis. Glucose, which stimulates anaplerosis via pyruvate carboxylase, had the same suppressive effect on α-cell cAMP but with lower potency. Similarly to mouse islets, leucine suppressed glucagon secretion from human islets under hypoglycemic conditions. Conclusions These findings highlight an important role for physiological levels of leucine in the metabolic regulation of α-cell cAMP and glucagon secretion. Leucine functions primarily through an α-cell intrinsic effect that is dependent on glutamate dehydrogenase, in addition to the well-established α-cell regulation by β/δ-cell paracrine signaling. Our results suggest that mitochondrial anaplerosis-cataplerosis facilitates the glucagonostatic effect of both leucine and glucose, which cooperatively suppress α-cell tone by reducing cAMP.
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Affiliation(s)
- Emily R. Knuth
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Hannah R. Foster
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Erli Jin
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Matthew J. Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
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34
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Spears E, Stanley JE, Shou M, Yin L, Li X, Dai C, Bradley A, Sellick K, Poffenberger G, Coate KC, Shrestha S, Jenkins R, Sloop KW, Wilson KT, Attie AD, Keller MP, Chen W, Powers AC, Dean ED. Pancreatic islet α cell function and proliferation requires the arginine transporter SLC7A2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552656. [PMID: 37645716 PMCID: PMC10461917 DOI: 10.1101/2023.08.10.552656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Interrupting glucagon signaling decreases gluconeogenesis and the fractional extraction of amino acids by liver from blood resulting in lower glycemia. The resulting hyperaminoacidemia stimulates α cell proliferation and glucagon secretion via a liver-α cell axis. We hypothesized that α cells detect and respond to circulating amino acids levels via a unique amino acid transporter repertoire. We found that Slc7a2ISLC7A2 is the most highly expressed cationic amino acid transporter in α cells with its expression being three-fold greater in α than β cells in both mouse and human. Employing cell culture, zebrafish, and knockout mouse models, we found that the cationic amino acid arginine and SLC7A2 are required for α cell proliferation in response to interrupted glucagon signaling. Ex vivo and in vivo assessment of islet function in Slc7a2-/- mice showed decreased arginine-stimulated glucagon and insulin secretion. We found that arginine activation of mTOR signaling and induction of the glutamine transporter SLC38A5 was dependent on SLC7A2, showing that both's role in α cell proliferation is dependent on arginine transport and SLC7A2. Finally, we identified single nucleotide polymorphisms in SLC7A2 associated with HbA1c. Together, these data indicate a central role for SLC7A2 in amino acid-stimulated α cell proliferation and islet hormone secretion.
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Affiliation(s)
- Erick Spears
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Biology, Belmont University, Nashville, TN
| | - Jade E. Stanley
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
| | - Matthew Shou
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Linlin Yin
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
| | - Xuan Li
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
| | - Chunhua Dai
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Amber Bradley
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Katelyn Sellick
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Greg Poffenberger
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Katie C. Coate
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Shristi Shrestha
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Regina Jenkins
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Kyle W. Sloop
- Diabetes and Complications, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Keith T. Wilson
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
- Center for Mucosal Inflammation and Cancer, Vanderbilt University Medical Center, Nashville, TN
- Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - Alan D. Attie
- Department of Biochemistry, University of Wisconsin, Madison, WI
| | - Mark P. Keller
- Department of Biochemistry, University of Wisconsin, Madison, WI
| | - Wenbiao Chen
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
| | - Alvin C. Powers
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
| | - E. Danielle Dean
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN
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35
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Brooks EP, Sussel L. Not the second fiddle: α cell development, identity, and function in health and diabetes. J Endocrinol 2023; 258:e220297. [PMID: 37171828 PMCID: PMC10524258 DOI: 10.1530/joe-22-0297] [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: 04/28/2023] [Accepted: 05/12/2023] [Indexed: 05/13/2023]
Abstract
Historic and emerging studies provide evidence for the deterioration of pancreatic α cell function and identity in diabetes mellitus. Increased access to human tissue and the availability of more sophisticated molecular technologies have identified key insights into how α cell function and identity are preserved in healthy conditions and how they become dysfunctional in response to stress. These studies have revealed evidence of impaired glucagon secretion, shifts in α cell electrophysiology, changes in α cell mass, dysregulation of α cell transcription, and α-to-β cell conversion prior to and during diabetes. In this review, we outline the current state of research on α cell identity in health and disease. Evidence in model organisms and humans suggests that in addition to β cell dysfunction, diabetes is associated with a fundamental dysregulation of α cell identity. Importantly, epigenetic studies have revealed that α cells retain more poised and open chromatin at key cell-specific and diabetes-dysregulated genes, supporting the model that the inherent epigenetic plasticity of α cells makes them susceptible to the transcriptional changes that potentiate the loss of identity and function seen in diabetes. Thus, additional research into the maintenance of α cell identity and function is critical to fully understanding diabetes. Furthermore, these studies suggest α cells could represent an alternative source of new β cells for diabetes treatment.
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Affiliation(s)
- Elliott P Brooks
- Barbara Davis Center for Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA
| | - Lori Sussel
- Barbara Davis Center for Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA
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36
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Taurino G, Chiu M, Bianchi MG, Griffini E, Bussolati O. The SLC38A5/SNAT5 amino acid transporter: from pathophysiology to pro-cancer roles in the tumor microenvironment. Am J Physiol Cell Physiol 2023; 325:C550-C562. [PMID: 37458433 DOI: 10.1152/ajpcell.00169.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/11/2023] [Accepted: 07/11/2023] [Indexed: 08/09/2023]
Abstract
SLC38A5/SNAT5 is a system N transporter that can mediate net inward or outward transmembrane fluxes of neutral amino acids coupled with Na+ (symport) and H+ (antiport). Its preferential substrates are not only amino acids with side chains containing amide (glutamine and asparagine) or imidazole (histidine) groups, but also serine, glycine, and alanine are transported by the carrier. Expressed in the pancreas, intestinal tract, brain, liver, bone marrow, and placenta, it is regulated at mRNA and protein levels by mTORC1 and WNT/β-catenin pathways, and it is sensitive to pH, nutritional stress, inflammation, and hypoxia. SNAT5 expression has been found to be altered in pathological conditions such as chronic inflammatory diseases, gestational complications, chronic metabolic acidosis, and malnutrition. Growing experimental evidence shows that SNAT5 is overexpressed in several types of cancer cells. Moreover, recently published results indicate that SNAT5 expression in stromal cells can support the metabolic exchanges occurring in the tumor microenvironment of asparagine-auxotroph tumors. We review the functional role of the SNAT5 transporter in pathophysiology and propose that, due to its peculiar operational and regulatory features, SNAT5 may play important pro-cancer roles when expressed either in neoplastic or in stromal cells of glutamine-auxotroph tumors.NEW & NOTEWORTHY The transporter SLC38A5/SNAT5 provides net influx or efflux of glutamine, asparagine, and serine. These amino acids are of particular metabolic relevance in several conditions. Changes in transporter expression or activity have been described in selected types of human cancers, where SNAT5 can mediate amino acid exchanges between tumor and stromal cells, thus providing a potential therapeutic target. This is the first review that recapitulates the characteristics and roles of the transporter in physiology and pathology.
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Affiliation(s)
- Giuseppe Taurino
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
- MRH-Microbiome Research Hub, University of Parma, Parma, Italy
| | - Martina Chiu
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Massimiliano G Bianchi
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
- MRH-Microbiome Research Hub, University of Parma, Parma, Italy
| | - Erika Griffini
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Ovidio Bussolati
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
- MRH-Microbiome Research Hub, University of Parma, Parma, Italy
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37
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Lubaczeuski C, Bozadjieva-Kramer N, Louzada RA, Gittes GK, Leibowitz G, Bernal-Mizrachi E. Time-dependent effects of endogenous hyperglucagonemia on glucose homeostasis and hepatic glucagon action. JCI Insight 2023; 8:e162255. [PMID: 37140984 PMCID: PMC10393226 DOI: 10.1172/jci.insight.162255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 05/03/2023] [Indexed: 05/05/2023] Open
Abstract
Elevation of glucagon levels and increase in α cell proliferation is associated with states of hyperglycemia in diabetes. A better understanding of the molecular mechanisms governing glucagon secretion could have major implications for understanding abnormal responses to hypoglycemia in patients with diabetes and provide novel avenues for diabetes management. Using mice with inducible induction of Rheb1 in α cells (αRhebTg mice), we showed that short-term activation of mTORC1 signaling is sufficient to induce hyperglucagonemia through increased glucagon secretion. Hyperglucagonemia in αRhebTg mice was also associated with an increase in α cell size and mass expansion. This model allowed us to identify the effects of chronic and short-term hyperglucagonemia on glucose homeostasis by regulating glucagon signaling in the liver. Short-term hyperglucagonemia impaired glucose tolerance, which was reversible over time. Liver glucagon resistance in αRhebTg mice was associated with reduced expression of the glucagon receptor and genes involved in gluconeogenesis, amino acid metabolism, and urea production. However, only genes regulating gluconeogenesis returned to baseline upon improvement of glycemia. Overall, these studies demonstrate that hyperglucagonemia exerts a biphasic response on glucose metabolism: Short-term hyperglucagonemia lead to glucose intolerance, whereas chronic exposure to glucagon reduced hepatic glucagon action and improved glucose tolerance.
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Affiliation(s)
- Camila Lubaczeuski
- Department of Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Nadejda Bozadjieva-Kramer
- Veterans Affairs Ann Arbor Healthcare System, Research Service, Ann Arbor, Michigan, USA
- Department of Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Ruy A. Louzada
- Department of Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - George K. Gittes
- Childrens Hospital, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Gil Leibowitz
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Ernesto Bernal-Mizrachi
- Department of Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Diabetes Unit and Endocrine Service, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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38
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Hamilton A, Eliasson L, Knudsen JG. Amino acids and the changing face of the α-cell. Peptides 2023:171039. [PMID: 37295651 DOI: 10.1016/j.peptides.2023.171039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/31/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
Glucagon has long been defined by its glucogenic action and as a result α-cells have been characterised based largely on their interaction with glucose. Recent findings have challenged this preconception, bringing to the fore the significant role glucagon plays in amino acid breakdown and underlining the importance of amino acids in glucagon secretion. The challenge that remains is defining the mechanism that underlie these effects - understanding which amino acids are most important, how they act on the α-cell and how their actions integrate with other fuels such as glucose and fatty acids. This review will describe the current relationship between amino acids and glucagon and how we can use this knowledge to redefine the α-cell.
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Affiliation(s)
- Alexander Hamilton
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Denmark; Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden.
| | - Lena Eliasson
- Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden.
| | - Jakob G Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Denmark.
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39
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Kawamori D, Sasaki S. Newly discovered knowledge pertaining to glucagon and its clinical applications. J Diabetes Investig 2023. [PMID: 37052948 DOI: 10.1111/jdi.14009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 04/14/2023] Open
Abstract
Glucagon has been defined as an 'insulin counteracting hormone', which raises blood glucose levels. Recent progress in basic research has shown that glucagon is closely involved in glucose and amino acid metabolism. Additionally, its secretion is intricately, but precisely, regulated by various mechanisms involving molecules in addition to glucose, thus showing its critical role in systemic nutrient metabolism. An innovative dual-antibody-linked immunosorbent assay for glucagon that improves measurement accuracy has been developed, and substantial clinical findings have been obtained using this new system. This discovery expanded the pathophysiological significance of glucagon and accelerated the development of its clinical applications in diabetes.
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Grants
- 21K08576 Ministry of Education, Culture, Sports, Science, and Technology in Japan
- 21K20902 Ministry of Education, Culture, Sports, Science, and Technology in Japan
- 22K16395 Ministry of Education, Culture, Sports, Science, and Technology in Japan
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Affiliation(s)
- Dan Kawamori
- Medical Education Center, Faculty of Medicine, Osaka University, Osaka, Japan
- Postgraduate Medical Training Center, Osaka University Hospital, Osaka University, Osaka, Japan
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shugo Sasaki
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
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40
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Hædersdal S, Andersen A, Knop FK, Vilsbøll T. Revisiting the role of glucagon in health, diabetes mellitus and other metabolic diseases. Nat Rev Endocrinol 2023; 19:321-335. [PMID: 36932176 DOI: 10.1038/s41574-023-00817-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/17/2023] [Indexed: 03/19/2023]
Abstract
Insulin and glucagon exert opposing effects on glucose metabolism and, consequently, pancreatic islet β-cells and α-cells are considered functional antagonists. The intra-islet hypothesis has previously dominated the understanding of glucagon secretion, stating that insulin acts to inhibit the release of glucagon. By contrast, glucagon is a potent stimulator of insulin secretion and has been used to test β-cell function. Over the past decade, α-cells have received increasing attention due to their ability to stimulate insulin secretion from neighbouring β-cells, and α-cell-β-cell crosstalk has proven central for glucose homeostasis in vivo. Glucagon is not only the counter-regulatory hormone to insulin in glucose metabolism but also glucagon secretion is more susceptible to changes in the plasma concentration of certain amino acids than to changes in plasma concentrations of glucose. Thus, the actions of glucagon also include a central role in amino acid turnover and hepatic fat oxidation. This Review provides insights into glucagon secretion, with a focus on the local paracrine actions on glucagon and the importance of α-cell-β-cell crosstalk. We focus on dysregulated glucagon secretion in obesity, non-alcoholic fatty liver disease and type 2 diabetes mellitus. Lastly, the future potential of targeting hyperglucagonaemia and applying dual and triple receptor agonists with glucagon receptor-activating properties in combination with incretin hormone receptor agonism is discussed.
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Affiliation(s)
- Sofie Hædersdal
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark.
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark.
| | - Andreas Andersen
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark
| | - Filip K Knop
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark.
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark.
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
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41
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Kjeldsen SAS, Richter MM, Jensen NJ, Nilsson MSD, Heinz N, Nybing JD, Linden FH, Høgh-Schmidt E, Boesen MP, Madsbad S, Vilstrup H, Schiødt FV, Møller A, Nørgaard K, Schmidt S, Rashu EB, Gluud LL, Haugaard SB, Holst JJ, Rungby J, Wewer Albrechtsen NJ. Development of a glucagon sensitivity test in humans: Pilot data and the GLUSENTIC study protocol. Peptides 2023; 161:170938. [PMID: 36596314 DOI: 10.1016/j.peptides.2022.170938] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/30/2022] [Accepted: 12/30/2022] [Indexed: 01/02/2023]
Abstract
A physiological feedback system exists between hepatocytes and the alpha cells, termed the liver-alpha cell axis and refers to the relationship between amino acid-stimulated glucagon secretion and glucagon-stimulated amino acid catabolism. Several reports indicate that non-alcoholic fatty liver disease (NAFLD) disrupts the liver-alpha cell axis, because of impaired glucagon receptor signaling (glucagon resistance). However, no experimental test exists to assess glucagon resistance in humans. The objective was to develop an experimental test to determine glucagon sensitivity with respect to amino acid and glucose metabolism in humans. The proposed glucagon sensitivity test (comprising two elements: 1) i.v. injection of 0.2 mg glucagon and 2) infusion of mixed amino acids 331 mg/hour/kg) is based on nine pilot studies which are presented. Calculation of a proposed glucagon sensitivity index with respect to amino acid catabolism is also described. Secondly, we describe a complete study protocol (GLUSENTIC) according to which the glucagon sensitivity test will be applied in a cross-sectional study currently taking place. 65 participants including 20 individuals with a BMI 18.6-25 kg/m2, 30 individuals with a BMI ≥ 25-40 kg/m2, and 15 individuals with type 1 diabetes with a BMI between 18.6 and 40 kg/m2 will be included. Participants will be grouped according to their degree of hepatic steatosis measured by whole-liver magnetic resonance imaging (MRI). The primary outcome measure will be differences in the glucagon sensitivity index between individuals with and without hepatic steatosis. Developing a glucagon sensitivity test and index may provide insight into the physiological and pathophysiological mechanism of glucagon action and glucagon-based therapies.
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Affiliation(s)
- Sasha A S Kjeldsen
- Department of Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, Bispebjerg, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Endocrinology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Michael M Richter
- Department of Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, Bispebjerg, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicole J Jensen
- Department of Endocrinology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Malin S D Nilsson
- Department of Endocrinology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Niklas Heinz
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Janus D Nybing
- Department of Radiology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Frederik H Linden
- Department of Radiology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Erik Høgh-Schmidt
- Department of Radiology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Mikael P Boesen
- Department of Radiology, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Sten Madsbad
- Department of Endocrinology, Hvidovre University Hospital, Hvidovre, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Andreas Møller
- Department of Gastroenterology and Gastrointestinal Surgery, Hvidovre University Hospital, Hvidovre, Denmark
| | - Kirsten Nørgaard
- Institute of Clinical Medicine, Faculty of Health Science, University of Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Herlev, Denmark
| | | | - Elias B Rashu
- Department of Gastroenterology and Gastrointestinal Surgery, Hvidovre University Hospital, Hvidovre, Denmark
| | - Lise L Gluud
- Department of Gastroenterology and Gastrointestinal Surgery, Hvidovre University Hospital, Hvidovre, Denmark; Institute of Clinical Medicine, Faculty of Health Science, University of Copenhagen, Denmark
| | - Steen B Haugaard
- Department of Endocrinology, Bispebjerg University Hospital, Copenhagen, Denmark; Institute of Clinical Medicine, Faculty of Health Science, University of 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
| | - Jørgen Rungby
- Department of Endocrinology, Bispebjerg University Hospital, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Herlev, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, Bispebjerg, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Cui X, Feng J, Wei T, Zhang L, Lang S, Yang K, Yang J, Liu J, Sterr M, Lickert H, Wei R, Hong T. Pancreatic alpha cell glucagon-liver FGF21 axis regulates beta cell regeneration in a mouse model of type 2 diabetes. Diabetologia 2023; 66:535-550. [PMID: 36331598 PMCID: PMC9892158 DOI: 10.1007/s00125-022-05822-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022]
Abstract
AIMS/HYPOTHESIS Glucagon receptor (GCGR) antagonism ameliorates hyperglycaemia and promotes beta cell regeneration in mouse models of type 2 diabetes. However, the underlying mechanisms remain unclear. The present study aimed to investigate the mechanism of beta cell regeneration induced by GCGR antagonism in mice. METHODS The db/db mice and high-fat diet (HFD)+streptozotocin (STZ)-induced mice with type 2 diabetes were treated with antagonistic GCGR monoclonal antibody (mAb), and the metabolic variables and islet cell quantification were evaluated. Plasma cytokine array and liver RNA sequencing data were used to screen possible mediators, including fibroblast growth factor 21 (FGF21). ELISA, quantitative RT-PCR and western blot were applied to verify FGF21 change. Blockage of FGF21 signalling by FGF21-neutralising antibody (nAb) was used to clarify whether FGF21 was involved in the effects of GCGR mAb on the expression of beta cell identity-related genes under plasma-conditional culture and hepatocyte co-culture conditions. FGF21 nAb-treated db/db mice, systemic Fgf21-knockout (Fgf21-/-) diabetic mice and hepatocyte-specific Fgf21-knockout (Fgf21Hep-/-) diabetic mice were used to reveal the involvement of FGF21 in beta cell regeneration. A BrdU tracing study was used to analyse beta cell proliferation in diabetic mice treated with GCGR mAb. RESULTS GCGR mAb treatment improved blood glucose control, and increased islet number (db/db 1.6±0.1 vs 0.8±0.1 per mm2, p<0.001; HFD+STZ 1.2±0.1 vs 0.5±0.1 per mm2, p<0.01) and area (db/db 2.5±0.2 vs 1.2±0.2%, p<0.001; HFD+STZ 1.0±0.1 vs 0.3±0.1%, p<0.01) in diabetic mice. The plasma cytokine array and liver RNA sequencing data showed that FGF21 levels in plasma and liver were upregulated by GCGR antagonism. The GCGR mAb induced upregulation of plasma FGF21 levels (db/db 661.5±40.0 vs 466.2±55.7 pg/ml, p<0.05; HFD+STZ 877.0±106.8 vs 445.5±54.0 pg/ml, p<0.05) and the liver levels of Fgf21 mRNA (db/db 3.2±0.5 vs 1.8±0.1, p<0.05; HFD+STZ 2.0±0.3 vs 1.0±0.2, p<0.05) and protein (db/db 2.0±0.2 vs 1.4±0.1, p<0.05; HFD+STZ 1.6±0.1 vs 1.0±0.1, p<0.01). Exposure to plasma or hepatocytes from the GCGR mAb-treated mice upregulated the mRNA levels of characteristic genes associated with beta cell identity in cultured mouse islets and a beta cell line, and blockage of FGF21 activity by an FGF21 nAb diminished this upregulation. Notably, the effects of increased beta cell number induced by GCGR mAb were attenuated in FGF21 nAb-treated db/db mice, Fgf21-/- diabetic mice and Fgf21Hep-/- diabetic mice. Moreover, GCGR mAb treatment enhanced beta cell proliferation in the two groups of diabetic mice, and this effect was weakened in Fgf21-/- and Fgf21Hep-/- mice. CONCLUSIONS/INTERPRETATION Our findings demonstrate that liver-derived FGF21 is involved in the GCGR antagonism-induced beta cell regeneration in a mouse model of type 2 diabetes.
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Affiliation(s)
- Xiaona Cui
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Jin Feng
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Institute of Diabetes and Regeneration Research, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Linxi Zhang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Shan Lang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Kun Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Junling Liu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Michael Sterr
- Institute of Diabetes and Regeneration Research, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China.
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China.
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China.
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China.
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Farag MR, Abo-Al-Ela HG, Alagawany M, Azzam MM, El-Saadony MT, Rea S, Di Cerbo A, Nouh DS. Effect of Quercetin Nanoparticles on Hepatic and Intestinal Enzymes and Stress-Related Genes in Nile Tilapia Fish Exposed to Silver Nanoparticles. Biomedicines 2023; 11:663. [PMID: 36979642 PMCID: PMC10045288 DOI: 10.3390/biomedicines11030663] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/10/2023] [Accepted: 02/15/2023] [Indexed: 02/25/2023] Open
Abstract
Recently, nanotechnology has become an important research field involved in the improvement of animals' productivity, including aquaculture. In this field, silver nanoparticles (AgNPs) have gained interest as antibacterial, antiviral, and antifungal agents. On the other hand, their extensive use in other fields increased natural water pollution causing hazardous effects on aquatic organisms. Quercetin is a natural polyphenolic compound of many plants and vegetables, and it acts as a potent antioxidant and therapeutic agent in biological systems. The current study investigated the potential mitigative effect of quercetin nanoparticles (QNPs) against AgNPs-induced toxicity in Nile tilapia via investigating liver function markers, hepatic antioxidant status, apoptosis, and bioaccumulation of silver residues in hepatic tissue in addition to the whole-body chemical composition, hormonal assay, intestinal enzymes activity, and gut microbiota. Fish were grouped into: control fish, fish exposed to 1.98 mg L-1 AgNPs, fish that received 400 mg L-1 QNPs, and fish that received QNPs and AgNPs at the same concentrations. All groups were exposed for 60 days. The moisture and ash contents of the AgNP group were significantly higher than those of the other groups. In contrast, the crude lipid and protein decreased in the whole body. AgNPs significantly increased serum levels of ALT, AST, total cholesterol, and triglycerides and decreased glycogen and growth hormone (*** p < 0.001). The liver and intestinal enzymes' activities were significantly inhibited (*** p < 0.001), while the oxidative damage liver enzymes, intestinal bacterial and Aeromonas counts, and Ag residues in the liver were significantly increased (*** p < 0.001, and * p < 0.05). AgNPs also significantly upregulated the expression of hepatic Hsp70, caspase3, and p53 genes (* p < 0.05). These findings indicate the oxidative and hepatotoxic effects of AgNPs. QNPs enhanced and restored physiological parameters and health status under normal conditions and after exposure to AgNPs.
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Affiliation(s)
- Mayada R. Farag
- Forensic Medicine and Toxicology Department, Veterinary Medicine Faculty, Zagazig University, Zagazig 44519, Egypt
| | - Haitham G. Abo-Al-Ela
- Genetics and Biotechnology, Department of Aquaculture, Faculty of Fish Resources, Suez University, Suez 43518, Egypt
| | - Mahmoud Alagawany
- Poultry Department, Faculty of Agriculture, Zagazig University, Zagazig 44519, Egypt
| | - Mahmoud M. Azzam
- Department of Animal Production College of Food & Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Mohamed T. El-Saadony
- Department of Agricultural Microbiology, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt
| | - Stefano Rea
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy
| | - Alessandro Di Cerbo
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy
| | - Doaa S. Nouh
- Anatomy and Embryology Department, Veterinary Medicine Faculty, Zagazig University, Zagazig 44519, Egypt
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Sanches JM, Zhao LN, Salehi A, Wollheim CB, Kaldis P. Pathophysiology of type 2 diabetes and the impact of altered metabolic interorgan crosstalk. FEBS J 2023; 290:620-648. [PMID: 34847289 DOI: 10.1111/febs.16306] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 10/14/2021] [Accepted: 11/29/2021] [Indexed: 02/06/2023]
Abstract
Diabetes is a complex and multifactorial disease that affects millions of people worldwide, reducing the quality of life significantly, and results in grave consequences for our health care system. In type 2 diabetes (T2D), the lack of β-cell compensatory mechanisms overcoming peripherally developed insulin resistance is a paramount factor leading to disturbed blood glucose levels and lipid metabolism. Impaired β-cell functions and insulin resistance have been studied extensively resulting in a good understanding of these pathways but much less is known about interorgan crosstalk, which we define as signaling between tissues by secreted factors. Besides hormones and organokines, dysregulated blood glucose and long-lasting hyperglycemia in T2D is associated with changes in metabolism with metabolites from different tissues contributing to the development of this disease. Recent data suggest that metabolites, such as lipids including free fatty acids and amino acids, play important roles in the interorgan crosstalk during the development of T2D. In general, metabolic remodeling affects physiological homeostasis and impacts the development of T2D. Hence, we highlight the importance of metabolic interorgan crosstalk in this review to gain enhanced knowledge of the pathophysiology of T2D, which may lead to new therapeutic approaches to treat this disease.
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Affiliation(s)
| | - Li Na Zhao
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Albert Salehi
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Claes B Wollheim
- Department of Clinical Sciences, Lund University, Malmö, Sweden.,Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Philipp Kaldis
- Department of Clinical Sciences, Lund University, Malmö, Sweden
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Abstract
Plasma glucose is tightly regulated via the secretion of the two glucose-regulating hormones insulin and glucagon. Situated next to the insulin-secreting β-cells, the α-cells produce and secrete glucagon-one of the body's few blood glucose-increasing hormones. Diabetes is a bihormonal disorder, resulting from both inadequate insulin secretion and dysregulation of glucagon. The year 2023 marks the 100th anniversary of the discovery of glucagon, making it particularly timely to highlight the roles of this systemic metabolic messenger in health and disease.
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Affiliation(s)
- Patrick E MacDonald
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
- Metabolic Physiology, Institute of Neuroscience and Physiology, University of Göteborg, Gothenburg, Sweden.
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Viloria K, Nasteska D, Ast J, Hasib A, Cuozzo F, Heising S, Briant LJB, Hewison M, Hodson DJ. GC-Globulin/Vitamin D-Binding Protein Is Required for Pancreatic α-Cell Adaptation to Metabolic Stress. Diabetes 2023; 72:275-289. [PMID: 36445949 DOI: 10.2337/db22-0326] [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: 04/06/2022] [Accepted: 11/14/2022] [Indexed: 12/02/2022]
Abstract
GC-globulin (GC), or vitamin D-binding protein, is a multifunctional protein involved in the transport of circulating vitamin 25(OH)D and fatty acids, as well as actin scavenging. In the pancreatic islets, the gene encoding GC, GC/Gc, is highly localized to glucagon-secreting α-cells. Despite this, the role of GC in α-cell function is poorly understood. We previously showed that GC is essential for α-cell morphology, electrical activity, and glucagon secretion. We now show that loss of GC exacerbates α-cell failure during metabolic stress. High-fat diet-fed GC-/- mice have basal hyperglucagonemia, which is associated with decreased α-cell size, impaired glucagon secretion and Ca2+ fluxes, and changes in glucose-dependent F-actin remodelling. Impairments in glucagon secretion can be rescued using exogenous GC to replenish α-cell GC levels, increase glucagon granule area, and restore the F-actin cytoskeleton. Lastly, GC levels decrease in α-cells of donors with type 2 diabetes, which is associated with changes in α-cell mass, morphology, and glucagon expression. Together, these data demonstrate an important role for GC in α-cell adaptation to metabolic stress.
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Affiliation(s)
- Katrina Viloria
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - Julia Ast
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - Annie Hasib
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - Federica Cuozzo
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - Silke Heising
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - Linford J B Briant
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, U.K
| | - Martin Hewison
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, U.K
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, U.K
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, U.K
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Winther-Sørensen M, Holst JJ, Wewer Albrechtsen NJ. The feedback cycles between glucose, amino acids and lipids and alpha cell secretion and their role in metabolic fatty liver disease. Curr Opin Lipidol 2023; 34:27-31. [PMID: 36373738 DOI: 10.1097/mol.0000000000000857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE OF REVIEW Glucagon increases hepatic glucose production and in patients with metabolic diseases, glucagon secretion is increased contributing to diabetic hyperglycemia. This review explores the role of amino acids and lipids in the regulation of glucagon secretion and how it may be disturbed in metabolic diseases such as obesity and metabolic associated fatty liver disease (MAFLD). RECENT FINDINGS Human and animal studies have shown that MAFLD is associated with glucagon resistance towards amino acid catabolism, resulting in elevated plasma levels of amino acids. A recent clinical study showed that MAFLD is also associated with glucagon resistance towards lipid metabolism. In contrast, MAFLD may not decrease hepatic sensitivity to the stimulatory effects of glucagon on glucose production. SUMMARY Elevated plasma levels of amino acids and lipids associated with MAFLD may cause diabetogenic hyperglucagonemia. MAFLD and glucagon resistance may therefore be causally linked to hyperglycemia and the development of type 2 diabetes.
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Affiliation(s)
- Marie Winther-Sørensen
- Department of Biomedical Sciences
- NNF Center for Protein Research, Faculty of Health and Medical Sciences
| | | | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences
- NNF Center for Protein Research, Faculty of Health and Medical Sciences
- Department for Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
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Gong Y, Yang B, Zhang D, Zhang Y, Tang Z, Yang L, Coate KC, Yin L, Covington BA, Patel RS, Siv WA, Sellick K, Shou M, Chang W, Danielle Dean E, Powers AC, Chen W. Hyperaminoacidemia induces pancreatic α cell proliferation via synergism between the mTORC1 and CaSR-Gq signaling pathways. Nat Commun 2023; 14:235. [PMID: 36646689 PMCID: PMC9842633 DOI: 10.1038/s41467-022-35705-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 12/20/2022] [Indexed: 01/18/2023] Open
Abstract
Glucagon has emerged as a key regulator of extracellular amino acid (AA) homeostasis. Insufficient glucagon signaling results in hyperaminoacidemia, which drives adaptive proliferation of glucagon-producing α cells. Aside from mammalian target of rapamycin complex 1 (mTORC1), the role of other AA sensors in α cell proliferation has not been described. Here, using both genders of mouse islets and glucagon receptor (gcgr)-deficient zebrafish (Danio rerio), we show α cell proliferation requires activation of the extracellular signal-regulated protein kinase (ERK1/2) by the AA-sensitive calcium sensing receptor (CaSR). Inactivation of CaSR dampened α cell proliferation, which was rescued by re-expression of CaSR or activation of Gq, but not Gi, signaling in α cells. CaSR was also unexpectedly necessary for mTORC1 activation in α cells. Furthermore, coactivation of Gq and mTORC1 induced α cell proliferation independent of hyperaminoacidemia. These results reveal another AA-sensitive mediator and identify pathways necessary and sufficient for hyperaminoacidemia-induced α cell proliferation.
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Affiliation(s)
- Yulong Gong
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China
| | - Bingyuan Yang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Dingdong Zhang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yue Zhang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Zihan Tang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Liu Yang
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Katie C Coate
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Linlin Yin
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Brittney A Covington
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Ravi S Patel
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Walter A Siv
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Katelyn Sellick
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Matthew Shou
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Wenhan Chang
- University of California San Francisco and San Francisco VA Medical Center, San Francisco, CA, 94158, USA
| | - E Danielle Dean
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
| | - Alvin C Powers
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Ave, Nashville, TN, 37232, USA
- VA Tennessee Valley Healthcare System, Nashville, TN, 37212, USA
| | - Wenbiao Chen
- Department of Molecular Physiology & Biophysics, Vanderbilt University, 2215 Garland Ave, Nashville, TN, 37232, USA.
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Pixner T, Stummer N, Schneider AM, Lukas A, Gramlinger K, Julian V, Thivel D, Mörwald K, Mangge H, Dalus C, Aigner E, Furthner D, Weghuber D, Maruszczak K. The relationship between glucose and the liver-alpha cell axis - A systematic review. Front Endocrinol (Lausanne) 2023; 13:1061682. [PMID: 36686477 PMCID: PMC9849557 DOI: 10.3389/fendo.2022.1061682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/13/2022] [Indexed: 01/06/2023] Open
Abstract
Until recently, glucagon was considered a mere antagonist to insulin, protecting the body from hypoglycemia. This notion changed with the discovery of the liver-alpha cell axis (LACA) as a feedback loop. The LACA describes how glucagon secretion and pancreatic alpha cell proliferation are stimulated by circulating amino acids. Glucagon in turn leads to an upregulation of amino acid metabolism and ureagenesis in the liver. Several increasingly common diseases (e.g., non-alcoholic fatty liver disease, type 2 diabetes, obesity) disrupt this feedback loop. It is important for clinicians and researchers alike to understand the liver-alpha cell axis and the metabolic sequelae of these diseases. While most of previous studies have focused on fasting concentrations of glucagon and amino acids, there is limited knowledge of their dynamics after glucose administration. The authors of this systematic review applied PRISMA guidelines and conducted PubMed searches to provide results of 8078 articles (screened and if relevant, studied in full). This systematic review aims to provide better insight into the LACA and its mediators (amino acids and glucagon), focusing on the relationship between glucose and the LACA in adult and pediatric subjects.
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Affiliation(s)
- Thomas Pixner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Nathalie Stummer
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Anna Maria Schneider
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Andreas Lukas
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Karin Gramlinger
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
| | - Valérie Julian
- Department of Sport Medicine and Functional Explorations, Diet and Musculoskeletal Health Team, Human Nutrition Research Center (CRNH), INRA, University Hospital of Clermont-Ferrand, University of Clermont Auvergne, Clermont-Ferrand, France
| | - David Thivel
- Laboratory of Metabolic Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), University of Clermont Auvergne, Clermont-Ferrand, France
| | - Katharina Mörwald
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Harald Mangge
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Christopher Dalus
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Elmar Aigner
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- First Department of Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Dieter Furthner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Daniel Weghuber
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Katharina Maruszczak
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
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50
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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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