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Suba K, Patel Y, Martin-Alonso A, Hansen B, Xu X, Roberts A, Norton M, Chung P, Shrewsbury J, Kwok R, Kalogianni V, Chen S, Liu X, Kalyviotis K, Rutter GA, Jones B, Minnion J, Owen BM, Pantazis P, Distaso W, Drucker DJ, Tan TM, Bloom SR, Murphy KG, Salem V. Intra-islet glucagon signalling regulates beta-cell connectivity, first-phase insulin secretion and glucose homoeostasis. Mol Metab 2024; 85:101947. [PMID: 38677509 PMCID: PMC11177084 DOI: 10.1016/j.molmet.2024.101947] [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: 01/31/2024] [Revised: 03/26/2024] [Accepted: 04/19/2024] [Indexed: 04/29/2024] Open
Abstract
OBJECTIVE Type 2 diabetes (T2D) is characterised by the loss of first-phase insulin secretion. We studied mice with β-cell selective loss of the glucagon receptor (Gcgrfl/fl X Ins-1Cre), to investigate the role of intra-islet glucagon receptor (GCGR) signalling on pan-islet [Ca2+]I activity and insulin secretion. METHODS Metabolic profiling was conducted on Gcgrβ-cell-/- and littermate controls. Crossing with GCaMP6f (STOP flox) animals further allowed for β-cell specific expression of a fluorescent calcium indicator. These islets were functionally imaged in vitro and in vivo. Wild-type mice were transplanted with islets expressing GCaMP6f in β-cells into the anterior eye chamber and placed on a high fat diet. Part of the cohort received a glucagon analogue (GCG-analogue) for 40 days and the control group were fed to achieve weight matching. Calcium imaging was performed regularly during the development of hyperglycaemia and in response to GCG-analogue treatment. RESULTS Gcgrβ-cell-/- mice exhibited higher glucose levels following intraperitoneal glucose challenge (control 12.7 mmol/L ± 0.6 vs. Gcgrβ-cell-/- 15.4 mmol/L ± 0.0 at 15 min, p = 0.002); fasting glycaemia was not different to controls. In vitro, Gcgrβ-cell-/- islets showed profound loss of pan-islet [Ca2+]I waves in response to glucose which was only partially rescued in vivo. Diet induced obesity and hyperglycaemia also resulted in a loss of co-ordinated [Ca2+]I waves in transplanted islets. This was reversed with GCG-analogue treatment, independently of weight-loss (n = 8). CONCLUSION These data provide novel evidence for the role of intra-islet GCGR signalling in sustaining synchronised [Ca2+]I waves and support a possible therapeutic role for glucagonergic agents to restore the insulin secretory capacity lost in T2D.
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Affiliation(s)
- K Suba
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom; Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - Y Patel
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - A Martin-Alonso
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - B Hansen
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - X Xu
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - A Roberts
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - M Norton
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - P Chung
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - J Shrewsbury
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - R Kwok
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - V Kalogianni
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - S Chen
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - X Liu
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - K Kalyviotis
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - G A Rutter
- CHUM Research Center, University of Montreal, QC, Canada; Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom; Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
| | - B Jones
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - J Minnion
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - B M Owen
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - P Pantazis
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - W Distaso
- Imperial College Business School, Imperial College London, London SW7 2AZ, United Kingdom
| | - D J Drucker
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Canada
| | - T M Tan
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - S R Bloom
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - K G Murphy
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom
| | - V Salem
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom; Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom; Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
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2
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Liu Y, Kimita W, Bharmal SH, Petrov MS. Response to lowering plasma glucose is characterised by decreased oxyntomodulin: Results from a randomised controlled trial. Diabetes Metab Syndr 2024; 18:103052. [PMID: 38901179 DOI: 10.1016/j.dsx.2024.103052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/13/2024] [Accepted: 06/10/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND With the prevalence of diabetes reaching an epidemic level, there is a growing interest in the investigation of its remission. Proglucagon-derived peptides (PGDP) have been shown to have a glucose-regulating effect. However, whether they play a role in diabetes remission remains poorly understood. AIM To investigate changes in plasma levels of PGDP in glycaemic responders versus non-responders. METHODS The study was a randomised placebo-controlled trial comprising 18 adults with prediabetes (registered at www. CLINICALTRIALS gov as NCT03889210). Following an overnight fast, participants consumed ketone β-hydroxybutyrate (KEβHB)-supplemented beverage and placebo beverage in crossover manner. Serial blood samples were collected from baseline to 150 min at 30-min intervals. The endpoints were changes in glucagon-like peptide-1 (GLP-1), glicentin, oxyntomodulin, glucagon, and major proglucagon fragment (MPGF). Participants were stratified into the 'responders' and 'non-responders' subgroups based on their glycaemic changes following the ingestion of KEβHB. The area under the curve (AUC) was calculated to estimate the accumulated changes in the studied PGDP and compared using paired-t test between the KEβHB and placebo beverages. RESULTS Responders had a significantly greater reduction in plasma glucose compared with non-responders following acute ketosis (p < 0.001). The AUC0-150 for oxyntomodulin was significantly lower following the KEβHB beverage compared with the placebo (p = 0.045) in responders, but not in non-responders (p = 0.512). No significant differences in AUCs0-150 were found for GLP-1, glicentin, glucagon, and MPGF in either responders or non-responders. CONCLUSION Oxyntomodulin is involved in lowering plasma glucose and may play an important role in diabetes remission.
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Affiliation(s)
- Yutong Liu
- School of Medicine, University of Auckland, Auckland, New Zealand
| | - Wandia Kimita
- School of Medicine, University of Auckland, Auckland, New Zealand
| | - Sakina H Bharmal
- School of Medicine, University of Auckland, Auckland, New Zealand
| | - Maxim S Petrov
- School of Medicine, University of Auckland, Auckland, New Zealand.
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3
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Guo W, Gao L, Mo H, Deng H, Zhao Y, Xu G. Mechano-sensor Piezo1 inhibits glucagon production in pancreatic α-cells. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167185. [PMID: 38653360 DOI: 10.1016/j.bbadis.2024.167185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 04/25/2024]
Abstract
OBJECTIVE Glucagon is a critical hormone regulating glucose metabolism. It stimulates the liver to release glucose under low blood sugar conditions, thereby maintaining blood glucose stability. Excessive glucagon secretion and hyperglycemia is observed in individuals with diabetes. Precise modulation of glucagon is significant to maintain glucose homeostasis. Piezo1 is a mechanosensitive ion channel capable of converting extracellular mechanical forces into intracellular signals, thus regulating hormonal synthesis and secretion. This study aims to investigate the role of Piezo1 in regulating glucagon production in α cells. METHODS The effects of Piezo1 on glucagon production were examined in normal- or high-fat diet fed α cell-specific Piezo1 knockout mice (Gcg-Piezo1-/-), and the murine pancreatic α cell line αTC1-6. Expression of Proglucagon was investigated by real-time PCR and western blotting. Plasma glucagon and insulin were detected by enzyme immunoassay. RESULTS Under both normal- and high-fat diet conditions, Gcg-Piezo1-/- mice exhibited increased pancreatic α cell proportion, hyperglucagonemia, impaired glucose tolerance, and activated pancreatic mTORC1 signaling. Activation of Piezo1 by its agonist Yoda1 or overexpression of Piezo1 led to decreased glucagon synthesis and suppressed mTOR signaling pathway in αTC1-6 cells. Additionally, the levels of glucagon in the medium were also reduced. Conversely, knockdown of Piezo1 produced opposite effects. CONCLUSION Our study uncovers the regulatory role of the Piezo1 ion channel in α cells. Piezo1 influences glucagon production by affecting mTOR signaling pathway.
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Affiliation(s)
- Wenying Guo
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Luyang Gao
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Haocong Mo
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Handan Deng
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Yawen Zhao
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China
| | - Geyang Xu
- Department of Physiology, School of Medicine, Jinan University, 601 Huangpu Avenue West, Tianhe District, Guangzhou, Guangdong 510632, China; Key Laboratory of Viral Pathogenesis & Infection Prevention and Control (Jinan University), Ministry of Education, Guangzhou 510632, Guangdong, China.
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4
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Moon JH, Choe HJ, Lim S. Pancreatic beta-cell mass and function and therapeutic implications of using antidiabetic medications in type 2 diabetes. J Diabetes Investig 2024; 15:669-683. [PMID: 38676410 PMCID: PMC11143426 DOI: 10.1111/jdi.14221] [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: 01/21/2024] [Revised: 03/23/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
Nowadays, the focus of diabetes treatment has switched from lowering the glucose level to preserving glycemic homeostasis and slowing the disease progression. The main pathophysiology of both type 1 diabetes and long-standing type 2 diabetes is pancreatic β-cell mass loss and dysfunction. According to recent research, human pancreatic β-cells possess the ability to proliferate in response to elevated insulin demands. It has been demonstrated that in insulin-resistant conditions in humans, such as obesity or pregnancy, the β-cell mass increases. This ability could be helpful in developing novel treatment approaches to restore a functional β-cell mass. Treatment strategies aimed at boosting β-cell function and mass may be a useful tool for managing diabetes mellitus and stopping its progression. This review outlines the processes of β-cell failure and detail the many β-cell abnormalities that manifest in people with diabetes mellitus. We also go over standard techniques for determining the mass and function of β-cells. Lastly, we provide the therapeutic implications of utilizing antidiabetic drugs in controlling the mass and function of pancreatic β-cells.
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Affiliation(s)
- Joon Ho Moon
- Department of Internal MedicineSeoul National University College of MedicineSeongnamSouth Korea
- Department of Internal MedicineSeoul National University Bundang HospitalSeongnamSouth Korea
| | - Hun Jee Choe
- Department of Internal MedicineHallym University Dongtan Sacred Heart HospitalHwaseongSouth Korea
| | - Soo Lim
- Department of Internal MedicineSeoul National University College of MedicineSeongnamSouth Korea
- Department of Internal MedicineSeoul National University Bundang HospitalSeongnamSouth Korea
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5
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Yin X, Ni G, Zhang X, Fu S, Li H, Gao Z. Tyrosine nitration of glucagon impairs its function: Extending the role of heme in T2D pathogenesis. J Inorg Biochem 2024; 255:112519. [PMID: 38507994 DOI: 10.1016/j.jinorgbio.2024.112519] [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: 11/18/2023] [Revised: 02/24/2024] [Accepted: 03/04/2024] [Indexed: 03/22/2024]
Abstract
New studies raise the possibility that the higher glucagon (GCG) level present in type 2 diabetes (T2D) is a compensatory mechanism to enhance β-cell function, rather than induce dysregulated glucose homeostasis, due to an important role for GCG that acts directly within the pancreas on insulin secretion by intra-islet GCG signaling. However, in states of poorly controlled T2D, pancreatic α cell mass increases (overproduced GCG) in response to insufficient insulin secretion, indicating decreased local GCG activity. The reason for this decrease is not clear. Recent evidence has uncovered a new role of heme in cellular signal transduction, and its mechanism involves reversible binding of heme to proteins. Considering that protein tyrosine nitration in diabetic islets increases and glucose-stimulated insulin secretion (GSIS) decreases, we speculated that heme modulates GSIS by transient interaction with GCG and catalyzing its tyrosine nitration, and the tyrosine nitration may impair GCG activity, leading to loss of intra-islet GCG signaling and markedly impaired insulin secretion. Data presented here elucidate a novel role for heme in disrupting local GCG signaling in diabetes. Heme bound to GCG and induced GCG tyrosine nitration. Two tyrosine residues in GCG were both sensitive to the nitrating species. Further, GCG was also demonstrated to be a preferred target peptide for tyrosine nitration by co-incubation with BSA. Tyrosine nitration impaired GCG stimulated cAMP-dependent signaling in islet β cells and decreased insulin release. Our results provided a new role of heme for impaired GSIS in the pathological process of diabetes.
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Affiliation(s)
- Xiaoying Yin
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Wuhan 430074, PR China; School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China
| | - Guoqi Ni
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Wuhan 430074, PR China; School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China
| | - Xuan Zhang
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Wuhan 430074, PR China; School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China
| | - Shitao Fu
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Wuhan 430074, PR China; School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China
| | - Hailing Li
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Wuhan 430074, PR China; School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China.
| | - Zhonghong Gao
- Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Wuhan 430074, PR China; School of Chemistry and Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074, PR China.
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6
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Varney MJ, Benovic JL. The Role of G Protein-Coupled Receptors and Receptor Kinases in Pancreatic β-Cell Function and Diabetes. Pharmacol Rev 2024; 76:267-299. [PMID: 38351071 PMCID: PMC10877731 DOI: 10.1124/pharmrev.123.001015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/01/2023] [Accepted: 12/07/2023] [Indexed: 02/16/2024] Open
Abstract
Type 2 diabetes (T2D) mellitus has emerged as a major global health concern that has accelerated in recent years due to poor diet and lifestyle. Afflicted individuals have high blood glucose levels that stem from the inability of the pancreas to make enough insulin to meet demand. Although medication can help to maintain normal blood glucose levels in individuals with chronic disease, many of these medicines are outdated, have severe side effects, and often become less efficacious over time, necessitating the need for insulin therapy. G protein-coupled receptors (GPCRs) regulate many physiologic processes, including blood glucose levels. In pancreatic β cells, GPCRs regulate β-cell growth, apoptosis, and insulin secretion, which are all critical in maintaining sufficient β-cell mass and insulin output to ensure euglycemia. In recent years, new insights into the signaling of incretin receptors and other GPCRs have underscored the potential of these receptors as desirable targets in the treatment of diabetes. The signaling of these receptors is modulated by GPCR kinases (GRKs) that phosphorylate agonist-activated GPCRs, marking the receptor for arrestin binding and internalization. Interestingly, genome-wide association studies using diabetic patient cohorts link the GRKs and arrestins with T2D. Moreover, recent reports show that GRKs and arrestins expressed in the β cell serve a critical role in the regulation of β-cell function, including β-cell growth and insulin secretion in both GPCR-dependent and -independent pathways. In this review, we describe recent insights into GPCR signaling and the importance of GRK function in modulating β-cell physiology. SIGNIFICANCE STATEMENT: Pancreatic β cells contain a diverse array of G protein-coupled receptors (GPCRs) that have been shown to improve β-cell function and survival, yet only a handful have been successfully targeted in the treatment of diabetes. This review discusses recent advances in our understanding of β-cell GPCR pharmacology and regulation by GPCR kinases while also highlighting the necessity of investigating islet-enriched GPCRs that have largely been unexplored to unveil novel treatment strategies.
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Affiliation(s)
- Matthew J Varney
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jeffrey L Benovic
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
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7
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Peng X, Ren H, Yang L, Tong S, Zhou R, Long H, Wu Y, Wang L, Wu Y, Zhang Y, Shen J, Zhang J, Qiu G, Wang J, Han C, Zhang Y, Zhou M, Zhao Y, Xu T, Tang C, Chen Z, Liu H, Chen L. Readily releasable β cells with tight Ca 2+-exocytosis coupling dictate biphasic glucose-stimulated insulin secretion. Nat Metab 2024; 6:238-253. [PMID: 38278946 DOI: 10.1038/s42255-023-00962-0] [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: 05/23/2022] [Accepted: 12/05/2023] [Indexed: 01/28/2024]
Abstract
Biphasic glucose-stimulated insulin secretion (GSIS) is essential for blood glucose regulation, but a mechanistic model incorporating the recently identified islet β cell heterogeneity remains elusive. Here, we show that insulin secretion is spatially and dynamically heterogeneous across the islet. Using a zinc-based fluorophore with spinning-disc confocal microscopy, we reveal that approximately 40% of islet cells, which we call readily releasable β cells (RRβs), are responsible for 80% of insulin exocytosis events. Although glucose up to 18.2 mM fully mobilized RRβs to release insulin synchronously (first phase), even higher glucose concentrations enhanced the sustained secretion from these cells (second phase). Release-incompetent β cells show similarities to RRβs in glucose-evoked Ca2+ transients but exhibit Ca2+-exocytosis coupling deficiency. A decreased number of RRβs and their altered secretory ability are associated with impaired GSIS progression in ob/ob mice. Our data reveal functional heterogeneity at the level of exocytosis among β cells and identify RRβs as a subpopulation of β cells that make a disproportionally large contribution to biphasic GSIS from mouse islets.
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Affiliation(s)
- Xiaohong Peng
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Bioland Laboratory, Guangzhou, China
| | - Huixia Ren
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Lu Yang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- The MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Shiyan Tong
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Renjie Zhou
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Haochen Long
- School of Software and Microelectronics, Peking University, Beijing, China
| | - Yunxiang Wu
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Lifen Wang
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yi Wu
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Yongdeng Zhang
- School of Life Sciences, Westlake University, Hangzhou, China
| | - Jiayu Shen
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Junwei Zhang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Guohua Qiu
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Jianyong Wang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Chengsheng Han
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Yulin Zhang
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Mengxuan Zhou
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Yiwen Zhao
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Tao Xu
- Guangzhou National Laboratory, Guangzhou, China
- School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China
| | - Chao Tang
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Zhixing Chen
- National Biomedical Imaging Center, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China
| | - Huisheng Liu
- Bioland Laboratory, Guangzhou, China.
- Guangzhou National Laboratory, Guangzhou, China.
- School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, China.
| | - Liangyi Chen
- New Cornerstone Science Laboratory, National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, School of Future Technology, Center for Life Sciences, Peking University, Beijing, China.
- PKU-IDG/McGovern Institute for Brain Research, Beijing, 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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9
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Fang XL, Zhang Q, Xue WW, Tao JH, Zou HD, Lin QR, Wang YL. Suppression of cAMP/PKA/CREB signaling ameliorates retinal injury in diabetic retinopathy. Kaohsiung J Med Sci 2023; 39:916-926. [PMID: 37338034 DOI: 10.1002/kjm2.12722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/28/2023] [Accepted: 05/29/2023] [Indexed: 06/21/2023] Open
Abstract
The blood-retinal barrier (BRB), homeostasis, neuronal integrity, and metabolic processes are all directly influenced by Müller cells, the most important retinal glial cells. We isolated primary Müller cells from Sprague-Dawley (SD) neonatal rats and treated them with glucose at varying doses. CCK-8 was used to quantify cellular viability, and a TUNEL assay was performed to detect cell apoptosis. ELISA, immunofluorescence, and western blotting were used to assess cAMP/PKA/CREB signaling, Kir4.1, AQP4, GFAP, and VEGF levels, respectively. H&E staining was used to examine histopathological alterations in diabetic retinopathy (DR)-affected retinal tissue in rats. As glucose concentration increases, gliosis of Müller cells became apparent, as evidenced by a decline in cell activity, an increase in apoptosis, downregulation of Kir4.1 level, and overexpression of GFAP, AQP4, and VEGF. Treatments with low, intermediate, and high glucose levels led to aberrant activation of cAMP/PKA/CREB signaling. Interestingly, blocking cAMP and PKA reduced high glucose-induced Müller cell damage and gliosis by a significant amount. Further in vivo results suggested that cAMP or PKA inhibition significantly improved edema, bleeding, and retinal disorders. Our findings showed that high glucose exacerbated Müller cell damage and gliosis via a mechanism involving cAMP/PKA/CREB signaling.
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Affiliation(s)
- Xiao-Ling Fang
- Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Qin Zhang
- Department of Ophthalmology, Jing'an District Central Hospital, Shanghai, China
| | - Wen-Wen Xue
- Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Jin-Hua Tao
- Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Hai-Dong Zou
- Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Qiu-Rong Lin
- Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Yu-Lan Wang
- Department of Ophthalmology, Shanghai Eye Diseases Prevention and Treatment Center, Shanghai Eye Hospital, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
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10
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Ramanadham S, Turk J, Bhatnagar S. Noncanonical Regulation of cAMP-Dependent Insulin Secretion and Its Implications in Type 2 Diabetes. Compr Physiol 2023; 13:5023-5049. [PMID: 37358504 PMCID: PMC10809800 DOI: 10.1002/cphy.c220031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Impaired glucose tolerance (IGT) and β-cell dysfunction in insulin resistance associated with obesity lead to type 2 diabetes (T2D). Glucose-stimulated insulin secretion (GSIS) from β-cells occurs via a canonical pathway that involves glucose metabolism, ATP generation, inactivation of K ATP channels, plasma membrane depolarization, and increases in cytosolic concentrations of [Ca 2+ ] c . However, optimal insulin secretion requires amplification of GSIS by increases in cyclic adenosine monophosphate (cAMP) signaling. The cAMP effectors protein kinase A (PKA) and exchange factor activated by cyclic-AMP (Epac) regulate membrane depolarization, gene expression, and trafficking and fusion of insulin granules to the plasma membrane for amplifying GSIS. The widely recognized lipid signaling generated within β-cells by the β-isoform of Ca 2+ -independent phospholipase A 2 enzyme (iPLA 2 β) participates in cAMP-stimulated insulin secretion (cSIS). Recent work has identified the role of a G-protein coupled receptor (GPCR) activated signaling by the complement 1q like-3 (C1ql3) secreted protein in inhibiting cSIS. In the IGT state, cSIS is attenuated, and the β-cell function is reduced. Interestingly, while β-cell-specific deletion of iPLA 2 β reduces cAMP-mediated amplification of GSIS, the loss of iPLA 2 β in macrophages (MØ) confers protection against the development of glucose intolerance associated with diet-induced obesity (DIO). In this article, we discuss canonical (glucose and cAMP) and novel noncanonical (iPLA 2 β and C1ql3) pathways and how they may affect β-cell (dys)function in the context of impaired glucose intolerance associated with obesity and T2D. In conclusion, we provide a perspective that in IGT states, targeting noncanonical pathways along with canonical pathways could be a more comprehensive approach for restoring β-cell function in T2D. © 2023 American Physiological Society. Compr Physiol 13:5023-5049, 2023.
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Affiliation(s)
- Sasanka Ramanadham
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Alabama, USA
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Alabama, USA
| | - John Turk
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sushant Bhatnagar
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Alabama, USA
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
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11
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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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12
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Wang K, Cui X, Li F, Xia L, Wei T, Liu J, Fu W, Yang J, Hong T, Wei R. Glucagon receptor blockage inhibits β-cell dedifferentiation through FoxO1. Am J Physiol Endocrinol Metab 2023; 324:E97-E113. [PMID: 36383639 DOI: 10.1152/ajpendo.00101.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glucagon-secreting pancreatic α-cells play pivotal roles in the development of diabetes. Glucagon promotes insulin secretion from β-cells. However, the long-term effect of glucagon on the function and phenotype of β-cells had remained elusive. In this study, we found that long-term glucagon intervention or glucagon intervention with the presence of palmitic acid downregulated β-cell-specific markers and inhibited insulin secretion in cultured β-cells. These results suggested that glucagon induced β-cell dedifferentiation under pathological conditions. Glucagon blockage by a glucagon receptor (GCGR) monoclonal antibody (mAb) attenuated glucagon-induced β-cell dedifferentiation. In primary islets, GCGR mAb treatment upregulated β-cell-specific markers and increased insulin content, suggesting that blockage of endogenous glucagon-GCGR signaling inhibited β-cell dedifferentiation. To investigate the possible mechanism, we found that glucagon decreased FoxO1 expression. FoxO1 inhibitor mimicked the effect of glucagon, whereas FoxO1 overexpression reversed the glucagon-induced β-cell dedifferentiation. In db/db mice and β-cell lineage-tracing diabetic mice, GCGR mAb lowered glucose level, upregulated plasma insulin level, increased β-cell area, and inhibited β-cell dedifferentiation. In aged β-cell-specific FoxO1 knockout mice (with the blood glucose level elevated as a diabetic model), the glucose-lowering effect of GCGR mAb was attenuated and the plasma insulin level, β-cell area, and β-cell dedifferentiation were not affected by GCGR mAb. Our results proved that glucagon induced β-cell dedifferentiation under pathological conditions, and the effect was partially mediated by FoxO1. Our study reveals a novel cross talk between α- and β-cells and is helpful to understand the pathophysiology of diabetes and discover new targets for diabetes treatment.NEW & NOTEWORTHY Glucagon-secreting pancreatic α-cells can interact with β-cells. However, the long-term effect of glucagon on the function and phenotype of β-cells has remained elusive. Our new finding shows that long-term glucagon induces β-cell dedifferentiation in cultured β-cells. FoxO1 inhibitor mimicks whereas glucagon signaling blockage by GCGR mAb reverses the effect of glucagon. In type 2 diabetic mice, GCGR mAb increases β-cell area, improves β-cell function, and inhibits β-cell dedifferentiation, and the effect is partially mediated by FoxO1.
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Affiliation(s)
- Kangli Wang
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Xiaona Cui
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Fei Li
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Li Xia
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Junling Liu
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Wei Fu
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, https://ror.org/04wwqze12Peking University Third Hospital, Beijing, China
- Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing, China
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13
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Insights into the Role of Glucagon Receptor Signaling in Metabolic Regulation from Pharmacological Inhibition and Tissue-Specific Knockout Models. Biomedicines 2022; 10:biomedicines10081907. [PMID: 36009454 PMCID: PMC9405517 DOI: 10.3390/biomedicines10081907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
While glucagon has long been recognized as the primary counter hormone to insulin’s actions, it has recently gained recognition as a metabolic regulator with its effects extending beyond control of glycemia. Recently developed models of tissue-specific glucagon receptor knockouts have advanced our understanding of this hormone, providing novel insight into the role it plays within organs as well as its systemic effects. Studies where the pharmacological blockade of the glucagon receptor has been employed have proved similarly valuable in the study of organ-specific and systemic roles of glucagon signaling. Studies carried out employing these tools demonstrate that glucagon indeed plays a role in regulating glycemia, but also in amino acid and lipid metabolism, systemic endocrine, and paracrine function, and in the response to cardiovascular injury. Here, we briefly review recent progress in our understanding of glucagon’s role made through inhibition of glucagon receptor signaling utilizing glucagon receptor antagonists and tissue specific genetic knockout models.
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14
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Ren H, Li Y, Han C, Yu Y, Shi B, Peng X, Zhang T, Wu S, Yang X, Kim S, Chen L, Tang C. Pancreatic α and β cells are globally phase-locked. Nat Commun 2022; 13:3721. [PMID: 35764654 PMCID: PMC9240067 DOI: 10.1038/s41467-022-31373-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 06/15/2022] [Indexed: 11/25/2022] Open
Abstract
The Ca2+ modulated pulsatile glucagon and insulin secretions by pancreatic α and β cells play a crucial role in glucose homeostasis. However, how α and β cells coordinate to produce various Ca2+ oscillation patterns is still elusive. Using a microfluidic device and transgenic mice, we recorded Ca2+ signals from islet α and β cells, and observed heterogeneous Ca2+ oscillation patterns intrinsic to each islet. After a brief period of glucose stimulation, α and β cells’ oscillations were globally phase-locked. While the activation of α cells displayed a fixed time delay of ~20 s to that of β cells, β cells activated with a tunable period. Moreover, islet α cell number correlated with oscillation frequency. We built a mathematical model of islet Ca2+ oscillation incorporating paracrine interactions, which quantitatively agreed with the experimental data. Our study highlights the importance of cell-cell interaction in generating stable but tunable islet oscillation patterns. The Ca2+ modulated pulsatile glucagon and insulin secretions by pancreatic α and β cells are critical in glucose homeostasis. Here the authors show that the Ca2+ oscillations of α and β cells are phase-locked, and that the oscillation pattern is tuned by paracrine interactions between α and β cells.
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Affiliation(s)
- Huixia Ren
- Center for Quantitative Biology, Peking University, Beijing, 100871, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Yanjun Li
- Center for Quantitative Biology, Peking University, Beijing, 100871, China.,Institute of Molecular Medicine, School of Future Technology, National Biomedical Imaging Center, Peking University, Beijing, 100871, China
| | - Chengsheng Han
- Institute of Molecular Medicine, School of Future Technology, National Biomedical Imaging Center, Peking University, Beijing, 100871, China
| | - Yi Yu
- Center for Quantitative Biology, Peking University, Beijing, 100871, China
| | - Bowen Shi
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Xiaohong Peng
- Institute of Molecular Medicine, School of Future Technology, National Biomedical Imaging Center, Peking University, Beijing, 100871, China
| | - Tianming Zhang
- Yuanpei College, Peking University, Beijing, 100871, China
| | - Shufang Wu
- Center for Quantitative Biology, Peking University, Beijing, 100871, China
| | - Xiaojing Yang
- Center for Quantitative Biology, Peking University, Beijing, 100871, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Sneppen Kim
- Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Liangyi Chen
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China. .,Institute of Molecular Medicine, School of Future Technology, National Biomedical Imaging Center, Peking University, Beijing, 100871, China.
| | - Chao Tang
- Center for Quantitative Biology, Peking University, Beijing, 100871, China. .,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
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15
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Karimova MV, Gvazava IG, Vorotelyak EA. Overcoming the Limitations of Stem Cell-Derived Beta Cells. Biomolecules 2022; 12:biom12060810. [PMID: 35740935 PMCID: PMC9221417 DOI: 10.3390/biom12060810] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022] Open
Abstract
Great advances in type 1 diabetes (T1D) and type 2 diabetes (T2D) treatment have been made to this day. However, modern diabetes therapy based on insulin injections and cadaveric islets transplantation has many disadvantages. That is why researchers are developing new methods to regenerate the pancreatic hormone-producing cells in vitro. The most promising approach is the generation of stem cell-derived beta cells that could provide an unlimited source of insulin-secreting cells. Recent studies provide methods to produce beta-like cell clusters that display glucose-stimulated insulin secretion—one of the key characteristics of the beta cell. However, in comparison with native beta cells, stem cell-derived beta cells do not undergo full functional maturation. In this paper we review the development and current state of various protocols, consider advantages, and propose ways to improve them. We examine molecular pathways, epigenetic modifications, intracellular components, and the microenvironment as a possible leverage to promote beta cell functional maturation. A possibility to create islet organoids from stem cell-derived components, as well as their encapsulation and further transplantation, is also examined. We try to combine modern research on beta cells and their crosstalk to create a holistic overview of developing insulin-secreting systems.
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Affiliation(s)
- Mariana V. Karimova
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, 119334 Moscow, Russia; (M.V.K.); (I.G.G.)
| | - Inessa G. Gvazava
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, 119334 Moscow, Russia; (M.V.K.); (I.G.G.)
| | - Ekaterina A. Vorotelyak
- Koltzov Institute of Developmental Biology of Russian Academy of Sciences, 119334 Moscow, Russia; (M.V.K.); (I.G.G.)
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
- Correspondence:
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16
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Thor D. G protein-coupled receptors as regulators of pancreatic islet functionality. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119235. [PMID: 35151663 DOI: 10.1016/j.bbamcr.2022.119235] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 01/03/2023]
Abstract
Glucose homeostasis is maintained by hormones secreted from different types of pancreatic islets and its dysregulation can result in diseases including diabetes mellitus. The secretion of hormones from pancreatic islets is highly complex and tightly controlled by G protein-coupled receptors (GPCRs). Moreover, GPCR signaling may play a role in enhancing islet cell replication and proliferation. Thus, targeting GPCRs offers a promising strategy for regulating the functionality of pancreatic islets. Here, available RNAseq datasets from human and mouse islets were used to identify the GPCR expression profile and the impact of GPCR signaling for normal islet functionality is discussed.
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Affiliation(s)
- Doreen Thor
- Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Johannisallee 30, 04103 Leipzig, Germany.
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17
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Cabrera O, Ficorilli J, Shaw J, Echeverri F, Schwede F, Chepurny OG, Leech CA, Holz GG. Intra-islet glucagon confers β-cell glucose competence for first-phase insulin secretion and favors GLP-1R stimulation by exogenous glucagon. J Biol Chem 2022; 298:101484. [PMID: 34896391 PMCID: PMC8789663 DOI: 10.1016/j.jbc.2021.101484] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 02/07/2023] Open
Abstract
We report that intra-islet glucagon secreted from α-cells signals through β-cell glucagon and GLP-1 receptors (GcgR and GLP-1R), thereby conferring to rat islets their competence to exhibit first-phase glucose-stimulated insulin secretion (GSIS). Thus, in islets not treated with exogenous glucagon or GLP-1, first-phase GSIS is abolished by a GcgR antagonist (LY2786890) or a GLP-1R antagonist (Ex[9-39]). Mechanistically, glucose competence in response to intra-islet glucagon is conditional on β-cell cAMP signaling because it is blocked by the cAMP antagonist prodrug Rp-8-Br-cAMPS-pAB. In its role as a paracrine hormone, intra-islet glucagon binds with high affinity to the GcgR, while also exerting a "spillover" effect to bind with low affinity to the GLP-1R. This produces a right shift of the concentration-response relationship for the potentiation of GSIS by exogenous glucagon. Thus, 0.3 nM glucagon fails to potentiate GSIS, as expected if similar concentrations of intra-islet glucagon already occupy the GcgR. However, 10 to 30 nM glucagon effectively engages the β-cell GLP-1R to potentiate GSIS, an action blocked by Ex[9-39] but not LY2786890. Finally, we report that the action of intra-islet glucagon to support insulin secretion requires a step-wise increase of glucose concentration to trigger first-phase GSIS. It is not measurable when GSIS is stimulated by a gradient of increasing glucose concentrations, as occurs during an oral glucose tolerance test in vivo. Collectively, such findings are understandable if defective intra-islet glucagon action contributes to the characteristic loss of first-phase GSIS in an intravenous glucose tolerance test that is diagnostic of type 2 diabetes in the clinical setting.
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Affiliation(s)
- Over Cabrera
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, USA.
| | - James Ficorilli
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, USA
| | - Janice Shaw
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, USA
| | | | - Frank Schwede
- Biolog Life Science Institute GmbH & Co KG, Bremen, Germany
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
| | - Colin A Leech
- Department of Medicine, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY) Upstate Medical University, Syracuse, New York, USA.
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18
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Holter MM, Saikia M, Cummings BP. Alpha-cell paracrine signaling in the regulation of beta-cell insulin secretion. Front Endocrinol (Lausanne) 2022; 13:934775. [PMID: 35957816 PMCID: PMC9360487 DOI: 10.3389/fendo.2022.934775] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/28/2022] [Indexed: 01/14/2023] Open
Abstract
As an incretin hormone, glucagon-like peptide 1 (GLP-1) lowers blood glucose levels by enhancing glucose-stimulated insulin secretion from pancreatic beta-cells. Therapies targeting the GLP-1 receptor (GLP-1R) use the classical incretin model as a physiological framework in which GLP-1 secreted from enteroendocrine L-cells acts on the beta-cell GLP-1R. However, this model has come into question, as evidence demonstrating local, intra-islet GLP-1 production has advanced the competing hypothesis that the incretin activity of GLP-1 may reflect paracrine signaling of GLP-1 from alpha-cells on GLP-1Rs on beta-cells. Additionally, recent studies suggest that alpha-cell-derived glucagon can serve as an additional, albeit less potent, ligand for the beta-cell GLP-1R, thereby expanding the role of alpha-cells beyond that of a counterregulatory cell type. Efforts to understand the role of the alpha-cell in the regulation of islet function have revealed both transcriptional and functional heterogeneity within the alpha-cell population. Further analysis of this heterogeneity suggests that functionally distinct alpha-cell subpopulations display alterations in islet hormone profile. Thus, the role of the alpha-cell in glucose homeostasis has evolved in recent years, such that alpha-cell to beta-cell communication now presents a critical axis regulating the functional capacity of beta-cells. Herein, we describe and integrate recent advances in our understanding of the impact of alpha-cell paracrine signaling on insulin secretory dynamics and how this intra-islet crosstalk more broadly contributes to whole-body glucose regulation in health and under metabolic stress. Moreover, we explore how these conceptual changes in our understanding of intra-islet GLP-1 biology may impact our understanding of the mechanisms of incretin-based therapeutics.
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Affiliation(s)
- Marlena M. Holter
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- *Correspondence: Marlena M. Holter,
| | - Mridusmita Saikia
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Bethany P. Cummings
- School of Medicine, Department of Surgery, Center for Alimentary and Metabolic Sciences, University of California, Davis, Sacramento, CA, United States
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19
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Jia Y, Liu Y, Feng L, Sun S, Sun G. Role of Glucagon and Its Receptor in the Pathogenesis of Diabetes. Front Endocrinol (Lausanne) 2022; 13:928016. [PMID: 35784565 PMCID: PMC9243425 DOI: 10.3389/fendo.2022.928016] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 05/13/2022] [Indexed: 11/24/2022] Open
Abstract
Various theories for the hormonal basis of diabetes have been proposed and debated over the past few decades. Insulin insufficiency was previously regarded as the only hormone deficiency directly leading to metabolic disorders associated with diabetes. Although glucagon and its receptor are ignored in this framework, an increasing number of studies have shown that they play essential roles in the development and progression of diabetes. However, the molecular mechanisms underlying the effects of glucagon are still not clear. In this review, recent research on the mechanisms by which glucagon and its receptor contribute to the pathogenesis of diabetes as well as correlations between GCGR mutation rates in populations and the occurrence of diabetes are summarized. Furthermore, we summarize how recent research clearly establishes glucagon as a potential therapeutic target for diabetes.
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Affiliation(s)
- Yunbo Jia
- Innovative Engineering Technology Research Center for Cell Therapy, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yang Liu
- Innovative Engineering Technology Research Center for Cell Therapy, Shengjing Hospital of China Medical University, Shenyang, China
| | - Linlin Feng
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Siyu Sun
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
- *Correspondence: Siyu Sun, ; Guangwei Sun,
| | - Guangwei Sun
- Innovative Engineering Technology Research Center for Cell Therapy, Shengjing Hospital of China Medical University, Shenyang, China
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
- *Correspondence: Siyu Sun, ; Guangwei Sun,
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