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Coulter-Parkhill A, Tanday N, Cobice D, McLaughlin CM, McClean S, Gault VA, Irwin N. Sustained metabolic benefits of ΔTRTX-Ac1, a tarantula venom-derived peptide, when administered together with exenatide in high-fat fed mice. Diabetes Obes Metab 2024; 26:329-338. [PMID: 37818589 DOI: 10.1111/dom.15319] [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: 07/24/2023] [Revised: 09/22/2023] [Accepted: 09/24/2023] [Indexed: 10/12/2023]
Abstract
AIM The aim of the present study was to assess the long-term therapeutic efficacy of a recently discovered 28 amino acid peptide, Δ-theraphotoxin-Ac1 (Δ-TRTX-Ac1), originally isolated from venom of the Aphonopelma chalcodes tarantula. Δ-TRTX-Ac has previously been shown to improve pancreatic beta-cell function and suppress appetite. MATERIALS AND METHODS Δ-TRTX-Ac1 was administered twice daily in high-fat fed (HFF) mice with streptozotocin (STZ)-induced insulin deficiency, namely HFF/STZ mice, for 28 days both alone and in combination with the venom-derived glucagon-like peptide-1 (GLP-1) mimetic, exenatide. RESULTS Initial pharmacokinetic profiling of ΔTRTX-Ac1 revealed a plasma half-life of 2 h in mice, with ΔTRTX-Ac1 also evidenced in the pancreas 12 h post-injection. Accordingly, HFF-STZ mice received twice-daily injections of Δ-TRTX-Ac1, exenatide or a combination of both peptides for 28 days. As anticipated, HFF/STZ mice presented with hyperglycaemia, impaired glucose tolerance, decreased plasma and pancreatic insulin and disturbed pancreatic islet morphology. Administration of ΔTRTX-Ac1 reduced body weight, improved glucose tolerance and augmented pancreatic insulin content while decreasing glucagon content. Exenatide had similar benefits on body weight and pancreatic hormone content while also reducing circulating glucose. ΔTRTX-Ac1 decreased energy expenditure on day 28 whereas exenatide had no impact. All treatment regimens restored pancreatic islet and beta-cell area towards lean control levels, which was linked to significantly elevated beta-cell proliferation rates. In terms of benefits of combined ΔTRTX-Ac1 and exenatide treatment over individual agents, there was augmentation of glucose tolerance and ambulatory activity with combination therapy, and these mice presented with increased pancreatic glucagon. CONCLUSION These data highlight the therapeutic promise of ΔTRTX-Ac1 for diabetes, with suggestion that benefits could be enhanced through combined administration with exenatide.
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Affiliation(s)
| | - Neil Tanday
- Diabetes Research Centre, Ulster University, Coleraine, UK
| | - Diego Cobice
- Diabetes Research Centre, Ulster University, Coleraine, UK
| | | | | | - Victor A Gault
- Diabetes Research Centre, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Centre, Ulster University, Coleraine, UK
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2
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Bany Bakar R, Reimann F, Gribble FM. The intestine as an endocrine organ and the role of gut hormones in metabolic regulation. Nat Rev Gastroenterol Hepatol 2023; 20:784-796. [PMID: 37626258 DOI: 10.1038/s41575-023-00830-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/25/2023] [Indexed: 08/27/2023]
Abstract
Gut hormones orchestrate pivotal physiological processes in multiple metabolically active tissues, including the pancreas, liver, adipose tissue, gut and central nervous system, making them attractive therapeutic targets in the treatment of obesity and type 2 diabetes mellitus. Most gut hormones are derived from enteroendocrine cells, but bioactive peptides that are derived from other intestinal epithelial cell types have also been implicated in metabolic regulation and can be considered gut hormones. A deeper understanding of the complex inter-organ crosstalk mediated by the intestinal endocrine system is a prerequisite for designing more effective drugs that are based on or target gut hormones and their receptors, and extending their therapeutic potential beyond obesity and diabetes mellitus. In this Review, we present an overview of gut hormones that are involved in the regulation of metabolism and discuss their action in the gastrointestinal system and beyond.
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Affiliation(s)
- Rula Bany Bakar
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Fiona M Gribble
- Wellcome Trust-MRC Institute of Metabolic Science Metabolic Research Laboratories, University of Cambridge, Cambridge, UK.
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3
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Shang J, Yan W, Cui X, Ma W, Wang Z, Liu N, Yi X, Guo T, Wei X, Sun Y, Hu H, Cui W, Chen L. Schisandrin B, a potential GLP-1R agonist, exerts anti-diabetic effects by stimulating insulin secretion. Mol Cell Endocrinol 2023; 577:112029. [PMID: 37495090 DOI: 10.1016/j.mce.2023.112029] [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: 05/23/2023] [Revised: 07/21/2023] [Accepted: 07/23/2023] [Indexed: 07/28/2023]
Abstract
Diabetes mellitus is a metabolic disease that is characterized by elevated blood sugar. Although glucagon-like peptide-1 receptor agonists (GLP-1RA) lower blood glucose in a glucose-dependent manner, most of them are macromolecule polypeptides. Macromolecular peptides are relatively expensive and inconvenient compared with small molecules. Therefore, this study sought to identify the small molecules binding to GLP-1R via cell membrane chromatography (CMC), confirm their agonistic activity, and further study its beneficial effects in a mouse model of type 2 diabetes mellitus (T2DM) induced by a combination of high-fat diet and streptozotocin. We used CMC, calcium imaging and molecular docking techniques to screen and identify the potential small molecule Schisandrin B (Sch B), which exhibits a strong binding effect to GLP-1R, from the small molecule library of traditional Chinese medicine. Through in-vitro experiments, we found that Sch B stimulated insulin secretion in β-TC-6 cells, while GLP-1R antagonist Exendin9-39, adenylate cyclase inhibitor SQ22536, and protein kinase A (PKA) inhibitor H89 could significantly inhibit the insulin secretion induced by Sch B. In vivo, Sch B significantly improved fasting blood glucose levels, intraperitoneal glucose tolerance test damage, and the status of pancreatic tissue damage, and reduced serum insulin levels, total cholesterol, triglyceride and low density lipoprotein in T2DM mice. These results indicate that Sch B alleviates T2DM by promoting insulin release through the GLP-1R/cAMP/PKA signaling pathway, suggesting that Sch B may be a potential GLP-1RA, which is expected to provide a new therapeutic strategy for the prevention and treatment of T2DM.
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Affiliation(s)
- Jia Shang
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Wenhui Yan
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, China
| | - Xin Cui
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Weina Ma
- School of Pharmacy, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China
| | - Zhuanzhuan Wang
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Na Liu
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Xinyao Yi
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Tingli Guo
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Xiaotong Wei
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yuzhuo Sun
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Hao Hu
- Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, China
| | - Wei Cui
- Department of Endocrinology and Second Department of Geriatrics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China; International Obesity and Metabolic Disease Research Center (IOMC), Xi'an Jiaotong University, Xi'an, 710061, China.
| | - Lina Chen
- Department of Endocrinology and Second Department of Geriatrics, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China; Department of Pharmacology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, China; Institute of Cardiovascular Sciences, Translational Medicine Institute, Xi'an Jiaotong University, Xi'an, 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, Xi'an, 710061, China; International Obesity and Metabolic Disease Research Center (IOMC), Xi'an Jiaotong University, Xi'an, 710061, China; Cardiometabolic Innovation Center, Ministry of Education, Xi'an, 710061, China.
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Nakhleh A, Goldenberg-Furmanov M, Goldstein R, Shohat M, Shehadeh N. A beneficial role of GLP-1 receptor agonist therapy in ABCC8-MODY (MODY 12). J Diabetes Complications 2023; 37:108566. [PMID: 37536118 DOI: 10.1016/j.jdiacomp.2023.108566] [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: 06/22/2023] [Revised: 07/15/2023] [Accepted: 07/24/2023] [Indexed: 08/05/2023]
Abstract
Maturity-onset diabetes of the young (MODY) is an inherited form of diabetes resulting from a mutation in a single gene. ABCC8-MODY is caused by mutations in the ABCC8 gene, which encodes sulfonylurea receptor 1 (SUR1), a regulatory component of the ATP-sensitive potassium (KATP) channel found in beta cells. In ABCC8-MODY, mutations in the ABCC8 gene interfere with insulin secretion in response to glucose. Recent evidence suggests that therapy with GLP-1 receptor agonists (GLP-1 RAs) may be beneficial in ABCC8-MODY. This report presents a successful treatment of a 49-year-old woman diagnosed with ABCC8-MODY using the GLP-1 RA semaglutide. The patient, who had been previously receiving insulin therapy, experienced significant improvements in glycemic control and weight loss after transitioning to semaglutide. GLP-1 RAs potentially enhance insulin secretion in ABCC8-MODY by activating multiple signaling pathways involved in insulin secretion. The report highlights the potential of GLP-1 RA therapy as an alternative to sulfonylureas and insulin for individuals with ABCC8-MODY. GLP-1 RAs have previously demonstrated benefits in other forms of MODY. Understanding the molecular mechanisms through which GLP-1 RAs promote insulin secretion, including their effects on KATP channels and activation of PKA and Epac signaling, offers valuable insights into their therapeutic effects.
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Affiliation(s)
- Afif Nakhleh
- Diabetes and Endocrinology Clinic, Maccabi Healthcare Services, Haifa, Israel; Institute of Endocrinology, Diabetes and Metabolism, Rambam Health Care Campus, Haifa, Israel; The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
| | | | - Rayna Goldstein
- The Genetic Institute of Maccabi Health Services, Rehovot, Israel
| | - Mordechai Shohat
- The Genetic Institute of Maccabi Health Services, Rehovot, Israel
| | - Naim Shehadeh
- Diabetes and Endocrinology Clinic, Maccabi Healthcare Services, Haifa, Israel; Institute of Endocrinology, Diabetes and Metabolism, Rambam Health Care Campus, Haifa, Israel; The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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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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6
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Zaborska KE, Jordan KL, Thorson AS, Dadi PK, Schaub CM, Nakhe AY, Dickerson MT, Lynch JC, Weiss AJ, Dobson JR, Jacobson DA. Liraglutide increases islet Ca 2+ oscillation frequency and insulin secretion by activating hyperpolarization-activated cyclic nucleotide-gated channels. Diabetes Obes Metab 2022; 24:1741-1752. [PMID: 35546791 PMCID: PMC9843726 DOI: 10.1111/dom.14747] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 01/19/2023]
Abstract
AIM To determine whether hyperpolarization-activated cyclic nucleotide-gated (HCN) channels impact glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) modulation of islet Ca2+ handling and insulin secretion. METHODS The impact of liraglutide (GLP-1 analogue) on islet Ca2+ handling, HCN currents and insulin secretion was monitored with fluorescence microscopy, electrophysiology and enzyme immunoassays, respectively. Furthermore, liraglutide-mediated β-to-δ-cell cross-communication was assessed following selective ablation of either mouse islet δ or β cells. RESULTS Liraglutide increased β-cell Ca2+ oscillation frequency in mouse and human islets under stimulatory glucose conditions. This was dependent in part on liraglutide activation of HCN channels, which also enhanced insulin secretion. Similarly, liraglutide activation of HCN channels also increased β-cell Ca2+ oscillation frequency in islets from rodents exposed to a diabetogenic diet. Interestingly, liraglutide accelerated Ca2+ oscillations in a majority of islet δ cells, which showed synchronized Ca2+ oscillations equivalent to β cells; therefore, we assessed if either cell type was driving this liraglutide-mediated islet Ca2+ response. Although δ-cell loss did not impact liraglutide-mediated increase in β-cell Ca2+ oscillation frequency, β-cell ablation attenuated liraglutide-facilitated acceleration of δ-cell Ca2+ oscillations. CONCLUSION The data presented here show that liraglutide-induced stimulation of islet HCN channels augments Ca2+ oscillation frequency. As insulin secretion oscillates with β-cell Ca2+ , these findings have important implications for pulsatile insulin secretion that is probably enhanced by liraglutide activation of HCN channels and therapeutics that target GLP-1Rs for treating diabetes. Furthermore, these studies suggest that liraglutide as well as GLP-1-based therapies enhance δ-cell Ca2+ oscillation frequency and somatostatin secretion kinetics in a β-cell-dependent manner.
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Affiliation(s)
- Karolina E Zaborska
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Kelli L Jordan
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Ariel S Thorson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Charles M Schaub
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Arya Y Nakhe
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Joshua C Lynch
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Adam J Weiss
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - Jordyn R Dobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee
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El Eid L, Reynolds CA, Tomas A, Ben Jones. Biased Agonism and Polymorphic Variation at the GLP-1 Receptor: Implications for the Development of Personalised Therapeutics. Pharmacol Res 2022; 184:106411. [PMID: 36007775 DOI: 10.1016/j.phrs.2022.106411] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 10/15/2022]
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) is a well-studied incretin hormone receptor and target of several therapeutic drugs for type 2 diabetes (T2D), obesity and, more recently, cardiovascular disease. Some signalling pathways downstream of GLP-1R may be responsible for drug adverse effects such as nausea, while others mediate therapeutic outcomes of incretin-based T2D therapeutics. Understanding the interplay between different factors that alter signalling, trafficking, and receptor activity, including biased agonism, single nucleotide polymorphisms and structural modifications is key to develop the next-generation of personalised GLP-1R agonists. However, these interactions remain poorly described, especially for novel therapeutics such as dual and tri-agonists that target more than one incretin receptor. Comparison of GLP-1R structures in complex with G proteins and different peptide and non-peptide agonists has revealed novel insights into important agonist-residue interactions and networks crucial for receptor activation, recruitment of G proteins and engagement of specific signalling pathways. Here, we review the latest knowledge on GLP-1R structure and activation, providing structural evidence for biased agonism and delineating important networks associated with this phenomenon. We survey current biased agonists and multi-agonists at different stages of development, highlighting possible challenges in their translational potential. Lastly, we discuss findings related to non-synonymous genomic variants of GLP1R and the functional importance of specific residues involved in GLP-1R function. We propose that studies of GLP-1R polymorphisms, and specifically their effect on receptor dynamics and pharmacology in response to biased agonists, could have a significant impact in delineating precision medicine approaches and development of novel therapeutics.
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Affiliation(s)
- Liliane El Eid
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom
| | - Christopher A Reynolds
- Centre for Sport, Exercise and Life Sciences, Faculty of Health and Life Sciences, Coventry University, Alison Gingell Building, United Kingdom; School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Imperial College London, London, United Kingdom.
| | - Ben Jones
- Section of Endocrinology and Investigative Medicine, Imperial College London, London, United Kingdom.
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Huang Z, Liu L, Zhang J, Conde K, Phansalkar J, Li Z, Yao L, Xu Z, Wang W, Zhou J, Bi G, Wu F, Seeley RJ, Scott MM, Zhan C, Pang ZP, Liu J. Glucose-sensing glucagon-like peptide-1 receptor neurons in the dorsomedial hypothalamus regulate glucose metabolism. SCIENCE ADVANCES 2022; 8:eabn5345. [PMID: 35675406 PMCID: PMC9177072 DOI: 10.1126/sciadv.abn5345] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/21/2022] [Indexed: 05/23/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) regulates energy homeostasis via activation of the GLP-1 receptors (GLP-1Rs) in the central nervous system. However, the mechanism by which the central GLP-1 signal controls blood glucose levels, especially in different nutrient states, remains unclear. Here, we defined a population of glucose-sensing GLP-1R neurons in the dorsomedial hypothalamic nucleus (DMH), by which endogenous GLP-1 decreases glucose levels via the cross-talk between the hypothalamus and pancreas. Specifically, we illustrated the sufficiency and necessity of DMHGLP-1R in glucose regulation. The activation of the DMHGLP-1R neurons is mediated by a cAMP-PKA-dependent inhibition of a delayed rectifier potassium current. We also dissected a descending control of DMHGLP-1R -dorsal motor nucleus of the vagus nerve (DMV)-pancreas activity that can regulate glucose levels by increasing insulin release. Thus, our results illustrate how central GLP-1 action in the DMH can induce a nutrient state-dependent reduction in blood glucose level.
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Affiliation(s)
- Zhaohuan Huang
- National Engineering Laboratory for Brain-inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Anhui, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Ling Liu
- National Engineering Laboratory for Brain-inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Anhui, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Jian Zhang
- CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Anhui, China
| | - Kristie Conde
- Child Health Institute of New Jersey, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Jay Phansalkar
- Child Health Institute of New Jersey, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Zhongzhong Li
- National Engineering Laboratory for Brain-inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Anhui, China
| | - Lei Yao
- CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Anhui, China
| | - Zihui Xu
- Child Health Institute of New Jersey, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Wei Wang
- Department of Endocrinology and Laboratory for Diabetes, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, China
| | - Jiangning Zhou
- CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Anhui, China
| | - Guoqiang Bi
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Anhui, China
| | - Feng Wu
- National Engineering Laboratory for Brain-inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Anhui, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Randy J. Seeley
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael M. Scott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Cheng Zhan
- Department of Hematology, The First Affiliated Hospital, Life Science School, University of Science and Technology of China, Anhui, China
- National Institute of Biological Sciences, Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100084, China
| | - Zhiping P. Pang
- Child Health Institute of New Jersey, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
- Department of Neuroscience and Cell Biology, Rutgers University Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Ji Liu
- National Engineering Laboratory for Brain-inspired Intelligence Technology and Application, School of Information Science and Technology, University of Science and Technology of China, Anhui, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- CAS Key Laboratory of Brain Function and Diseases, Life Science School, University of Science and Technology of China, Anhui, China
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9
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Model JFA, Rocha DS, Fagundes ADC, Vinagre AS. Physiological and pharmacological actions of glucagon like peptide-1 (GLP-1) in domestic animals. Vet Anim Sci 2022; 16:100245. [PMID: 35372707 PMCID: PMC8966211 DOI: 10.1016/j.vas.2022.100245] [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: 12/03/2021] [Revised: 02/25/2022] [Accepted: 03/14/2022] [Indexed: 11/25/2022] Open
Abstract
GLP-1 improves peripheral glucose uptake in healthy dogs and cats. GLP-1 analogues administration in diabetic cats reduces exogenous insulin requirement. Dogs cardiomyocytes apoptosis is reduced by GLP-1-derived molecules action.
Analogues of glucagon like peptide-1 (GLP-1) and other drugs that increase this peptide half-life are used worldwide in human medicine to treat type 2 diabetes mellitus (DM) and obesity. These molecules can increase insulin release and satiety, interesting effects that could also be useful in the treatment of domestic animals pathologies, however their use in veterinary medicine are still limited. Considering the increasing incidence of DM and obesity in cats and dogs, the aim of this review is to summarize the available information about the physiological and pharmacological actions of GLP-1 in domestic animals and discuss about its potential applications in veterinary medicine. In diabetic dogs, the use of drugs based on GLP-1 actions reduced blood glucose and increased glucose uptake, while in diabetic cats they reduced glycemic variability and exogenous insulin administration. Thus, available evidence indicates that GLP-1 based drugs could become alternatives to DM treatment in domestic animals. Nevertheless, current data do not provide enough elements to recommend these drugs widespread clinical use.
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10
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Guccio N, Gribble FM, Reimann F. Glucose-Dependent Insulinotropic Polypeptide-A Postprandial Hormone with Unharnessed Metabolic Potential. Annu Rev Nutr 2022; 42:21-44. [PMID: 35609956 DOI: 10.1146/annurev-nutr-062320-113625] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is released from the upper small intestine in response to food intake and contributes to the postprandial control of nutrient disposition, including of sugars and fats. Long neglected as a potential therapeutic target, the GIPR axis has received increasing interest recently, with the emerging data demonstrating the metabolically favorable outcomes of adding GIPR agonism to GLP-1 receptor agonists in people with type 2 diabetes and obesity. This review examines the physiology of the GIP axis, from the mechanisms underlying GIP secretion from the intestine to its action on target tissues and therapeutic development. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Nunzio Guccio
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
| | - Fiona M Gribble
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
| | - Frank Reimann
- MRC Metabolic Diseases Unit, Wellcome Trust/MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; ,
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11
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Mayendraraj A, Rosenkilde MM, Gasbjerg LS. GLP-1 and GIP receptor signaling in beta cells - A review of receptor interactions and co-stimulation. Peptides 2022; 151:170749. [PMID: 35065096 DOI: 10.1016/j.peptides.2022.170749] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 02/07/2023]
Abstract
Glucagon-like peptide 1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) are two class B1 G protein-coupled receptors, which are stimulated by the gastrointestinal hormones GLP-1 and GIP, respectively. In the pancreatic beta cells, activation of both receptors lead to increased cyclic adenosine monophosphate (cAMP) and glucose-dependent insulin secretion. Marketed GLP-1R agonists such as dulaglutide, liraglutide, exenatide and semaglutide constitute an expanding drug class with beneficial effects for persons suffering from type 2 diabetes and/or obesity. In recent years another drug class, the GLP-1R-GIPR co-agonists, has emerged. Especially the peptide-based, co-agonist tirzepatide is a promising candidate for a better treatment of type 2 diabetes by improving glycemic control and weight reduction. The mechanism of action for tirzepatide include biased signaling of the GLP-1R as well as potent GIPR signaling. Since the implications of co-targeting these closely related receptors concomitantly are challenging to study in vivo, the pharmacodynamic mechanisms and downstream signaling pathways of the GLP-1R-GIPR co-agonists in general, are not fully elucidated. In this review, we present the individual signaling pathways for GLP-1R and GIPR in the pancreatic beta cell with a focus on the shared signaling pathways of the two receptors and interpret the implications of GLP-1R-GIPR co-activation in the light of recent co-activating therapeutic compounds.
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Affiliation(s)
- Ashok Mayendraraj
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lærke S Gasbjerg
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
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12
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Du H, Meng X, Yao Y, Xu J. The mechanism and efficacy of GLP-1 receptor agonists in the treatment of Alzheimer's disease. Front Endocrinol (Lausanne) 2022; 13:1033479. [PMID: 36465634 PMCID: PMC9714676 DOI: 10.3389/fendo.2022.1033479] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/27/2022] [Indexed: 11/18/2022] Open
Abstract
Since type 2 diabetes mellitus (T2DM) is a risk factor for Alzheimer's disease (AD) and both have the same pathogenesis (e.g., insulin resistance), drugs used to treat T2DM have been gradually found to reduce the progression of AD in AD models. Of these drugs, glucagon-like peptide 1 receptor (GLP-1R) agonists are more effective and have fewer side effects. GLP-1R agonists have reducing neuroinflammation and oxidative stress, neurotrophic effects, decreasing Aβ deposition and tau hyperphosphorylation in AD models, which may be a potential drug for the treatment of AD. However, this needs to be verified by further clinical trials. This study aims to summarize the current information on the mechanisms and effects of GLP-1R agonists in AD.
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Affiliation(s)
- Haiyang Du
- Division of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Xiaoyu Meng
- Division of Endocrinology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Branch of National Clinical Research Center for Metabolic Diseases, Hubei, China
| | - Yu Yao
- Division of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Jun Xu
- Division of Orthopedics, Department of Orthopedics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
- *Correspondence: Jun Xu,
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13
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Zheng W, Li L, Li H. Phytochemicals modulate pancreatic islet β cell function through glucagon-like peptide-1-related mechanisms. Biochem Pharmacol 2021; 197:114817. [PMID: 34717897 DOI: 10.1016/j.bcp.2021.114817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/22/2021] [Accepted: 10/25/2021] [Indexed: 11/19/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) receptor-based therapies have been developed and extensively applied in clinical practice. GLP-1 plays an important role in improving glycemic homeostasis by stimulating insulin biosynthesis and secretion, suppressing glucagon activity, delaying gastric emptying, and reducing appetite and food ingestion. Furthermore, GLP-1 has positive effects on β-cell function by promoting β-cell proliferation and neogenesis while simultaneously reducing apoptosis. Here, we summarize possible mechanisms of action of GLP-1 upon pancreatic islets as well as describe phytochemicals that modulate pancreatic islet β cell function through glucagon-like peptide-1-related mechanisms. Together, this information provides potential lead compound candidates against diabetes that function as GLP-1 receptor-based pharmacotherapy.
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Affiliation(s)
- Wanfang Zheng
- Institute of Pharmacology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - Linghuan Li
- Institute of Pharmacology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China
| | - Hanbing Li
- Institute of Pharmacology, Zhejiang University of Technology, Hangzhou 310014, People's Republic of China; Section of Endocrinology, School of Medicine, Yale University, New Haven 06520, USA.
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14
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Cao T, Tang M, Jiang P, Zhang B, Wu X, Chen Q, Zeng C, Li N, Zhang S, Cai H. A Potential Mechanism Underlying the Therapeutic Effects of Progesterone and Allopregnanolone on Ketamine-Induced Cognitive Deficits. Front Pharmacol 2021; 12:612083. [PMID: 33767621 PMCID: PMC7985688 DOI: 10.3389/fphar.2021.612083] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 01/29/2021] [Indexed: 11/13/2022] Open
Abstract
Ketamine exposure can model cognitive deficits associated with schizophrenia. Progesterone (PROG) and its active metabolite allopregnanolone (ALLO) have neuroprotective effects and the pathway involving progesterone receptor membrane component 1 (PGRMC1), epidermal growth factor receptor (EGFR), glucagon-like peptide-1 receptor (GLP-1R), phosphatidylinositol 3 kinase (PI3K), and protein kinase B (Akt) appears to play a key role in their neuroprotection. The present study aimed to investigate the effects of PROG (8,16 mg kg−1) and ALLO (8,16 mg kg−1) on the reversal of cognitive deficits induced by ketamine (30 mg kg−1) via the PGRMC1 pathway in rat brains, including hippocampus and prefrontal cortex (PFC). Cognitive performance was evaluated by Morris water maze (MWM) test. Western blot and real-time quantitative polymerase chain reaction were utilized to assess the expression changes of protein and mRNA. Additionally, concentrations of PROG and ALLO in plasma, hippocampus and PFC were measured by a liquid chromatography-tandem mass spectrometry method. We demonstrated that PROG or ALLO could reverse the impaired spatial learning and memory abilities induced by ketamine, accompanied with the upregulation of PGRMC1/EGFR/GLP-1R/PI3K/Akt pathway. Additionally, the coadministration of AG205 abolished their neuroprotective effects and induced cognitive deficits similar with ketamine. More importantly, PROG concentrations were markedly elevated in PROG-treated groups in hippocampus, PFC and plasma, so as for ALLO concentrations in ALLO-treated groups. Interestingly, ALLO (16 mg kg−1) significantly increased the levels of PROG. These findings suggest that PROG can exert its neuroprotective effects via activating the PGRMC1/EGFR/GLP-1R/PI3K/Akt pathway in the brain, whereas ALLO also restores cognitive deficits partially via increasing the level of PROG in the brain to activate the PGRMC1 pathway.
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Affiliation(s)
- Ting Cao
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - MiMi Tang
- Department of Pharmacy, Xiangya Hospital of Central South University, Changsha, China.,Institute of Hospital Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Pei Jiang
- Institute of Clinical Pharmacology, Jining First People's Hospital, Jining Medical University, Jining, China
| | - BiKui Zhang
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - XiangXin Wu
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - Qian Chen
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - CuiRong Zeng
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - NaNa Li
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - ShuangYang Zhang
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
| | - HuaLin Cai
- Department of Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Second Xiangya Hospital, Central South University, Changsha, China
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15
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Ježek P, Holendová B, Jabůrek M, Tauber J, Dlasková A, Plecitá-Hlavatá L. The Pancreatic β-Cell: The Perfect Redox System. Antioxidants (Basel) 2021; 10:antiox10020197. [PMID: 33572903 PMCID: PMC7912581 DOI: 10.3390/antiox10020197] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell insulin secretion, which responds to various secretagogues and hormonal regulations, is reviewed here, emphasizing the fundamental redox signaling by NADPH oxidase 4- (NOX4-) mediated H2O2 production for glucose-stimulated insulin secretion (GSIS). There is a logical summation that integrates both metabolic plus redox homeostasis because the ATP-sensitive K+ channel (KATP) can only be closed when both ATP and H2O2 are elevated. Otherwise ATP would block KATP, while H2O2 would activate any of the redox-sensitive nonspecific calcium channels (NSCCs), such as TRPM2. Notably, a 100%-closed KATP ensemble is insufficient to reach the -50 mV threshold plasma membrane depolarization required for the activation of voltage-dependent Ca2+ channels. Open synergic NSCCs or Cl- channels have to act simultaneously to reach this threshold. The resulting intermittent cytosolic Ca2+-increases lead to the pulsatile exocytosis of insulin granule vesicles (IGVs). The incretin (e.g., GLP-1) amplification of GSIS stems from receptor signaling leading to activating the phosphorylation of TRPM channels and effects on other channels to intensify integral Ca2+-influx (fortified by endoplasmic reticulum Ca2+). ATP plus H2O2 are also required for branched-chain ketoacids (BCKAs); and partly for fatty acids (FAs) to secrete insulin, while BCKA or FA β-oxidation provide redox signaling from mitochondria, which proceeds by H2O2 diffusion or hypothetical SH relay via peroxiredoxin "redox kiss" to target proteins.
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16
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Diz-Chaves Y, Herrera-Pérez S, González-Matías LC, Lamas JA, Mallo F. Glucagon-Like Peptide-1 (GLP-1) in the Integration of Neural and Endocrine Responses to Stress. Nutrients 2020; 12:nu12113304. [PMID: 33126672 PMCID: PMC7692797 DOI: 10.3390/nu12113304] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022] Open
Abstract
Glucagon like-peptide 1 (GLP-1) within the brain is produced by a population of preproglucagon neurons located in the caudal nucleus of the solitary tract. These neurons project to the hypothalamus and another forebrain, hindbrain, and mesolimbic brain areas control the autonomic function, feeding, and the motivation to feed or regulate the stress response and the hypothalamic-pituitary-adrenal axis. GLP-1 receptor (GLP-1R) controls both food intake and feeding behavior (hunger-driven feeding, the hedonic value of food, and food motivation). The activation of GLP-1 receptors involves second messenger pathways and ionic events in the autonomic nervous system, which are very relevant to explain the essential central actions of GLP-1 as neuromodulator coordinating food intake in response to a physiological and stress-related stimulus to maintain homeostasis. Alterations in GLP-1 signaling associated with obesity or chronic stress induce the dysregulation of eating behavior. This review summarized the experimental shreds of evidence from studies using GLP-1R agonists to describe the neural and endocrine integration of stress responses and feeding behavior.
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Affiliation(s)
- Yolanda Diz-Chaves
- CINBIO, Universidade de Vigo, Grupo FB3A, Laboratorio de Endocrinología, 36310 Vigo, Spain;
- Correspondence: (Y.D.-C.); (F.M.); Tel.: +34-(986)-130226 (Y.D.-C.); +34-(986)-812393 (F.M.)
| | - Salvador Herrera-Pérez
- CINBIO, Universidade de Vigo, Grupo FB3B, Laboratorio de Neurociencia, 36310 Vigo, Spain; (S.H.-P.); (J.A.L.)
| | | | - José Antonio Lamas
- CINBIO, Universidade de Vigo, Grupo FB3B, Laboratorio de Neurociencia, 36310 Vigo, Spain; (S.H.-P.); (J.A.L.)
| | - Federico Mallo
- CINBIO, Universidade de Vigo, Grupo FB3A, Laboratorio de Endocrinología, 36310 Vigo, Spain;
- Correspondence: (Y.D.-C.); (F.M.); Tel.: +34-(986)-130226 (Y.D.-C.); +34-(986)-812393 (F.M.)
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17
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Rago V, De Rose D, Santoro M, Panza S, Malivindi R, Andò S, D'Agata R, Aquila S. Human Sperm Express the Receptor for Glucagon-like Peptide-1 (GLP-1), Which Affects Sperm Function and Metabolism. Endocrinology 2020; 161:5802751. [PMID: 32157297 DOI: 10.1210/endocr/bqaa031] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/09/2020] [Indexed: 12/15/2022]
Abstract
AIM Glucagon-like peptide-1 (GLP-1) produces pleiotropic effects binding to the GLP-1 receptor (GLP1-R), potentiating insulin secretion in the pancreas. GLP1-R is expressed in peripheral tissues and evidence for its role in reproduction has come from knockout mice, although the relationship between GLP-1 and male fertility needs to be clarified. Given that human sperm is an insulin-sensitive and insulin-secreting cell, we hypothesized that the GLP-1/GLP1-R axis may be expressed and functional in these cells. RESULTS AND DISCUSSION We revealed the presence of GLP1-R by Western blotting and immunofluorescence analyses. Because Exendin-4 (Ex-4) displays similar functional properties to native GLP-1, we used this agonist to perform a dose-response study on progressive motility and cholesterol efflux, showing that 300 pM Ex-4 was the most effective treatment. These actions are mediated by GLP1-R and independent from sperm-secreted insulin. The exposure to Ex-4 fueled phosphatidylinositol-3-kinase (PI3K)/AKT signaling and was reversed by H89, indicating a protein kinase A (PKA)-dependence of GLP-1/GLP1-R signaling. It emerged that in sperm, insulin secretion regulated by Ex-4 did not occur in a strictly glucose-dependent manner. A stimulatory action of Ex-4/GLP1-R on lactate dehydrogenase and glucose-6-phosphate dehydrogenase (G6PDH) activities was observed. Ex-4/GLP1-R decreased triglycerides content concomitantly to enhanced lipase and acyl-coenzyme A (acyl-CoA) dehydrogenase activities, addressing a lipolytic effect. CONCLUSION Collectively, we discovered that human sperm is a new GLP1 incretin target, broadening our knowledge about the effects of the GLP1-R agonist in the male reproductive field. Further findings in humans should be conducted in the future to confirm it and to improve the translational aspect of this study.
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Affiliation(s)
- Vittoria Rago
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
| | - Daniela De Rose
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
- Centro Sanitario, University of Calabria Cosenza, Italy
| | - Marta Santoro
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
- Centro Sanitario, University of Calabria Cosenza, Italy
| | - Salvatore Panza
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
- Centro Sanitario, University of Calabria Cosenza, Italy
| | - Rocco Malivindi
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
| | - Sebastiano Andò
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
- Centro Sanitario, University of Calabria Cosenza, Italy
| | - Rosario D'Agata
- Department of Experimental and Clinical Medicine, University of Catania, Catania, Italy
| | - Saveria Aquila
- Department of Pharmacy and Sciences of Health and Nutrition, University of Calabria Cosenza, Italy
- Centro Sanitario, University of Calabria Cosenza, Italy
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18
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Hartig SM, Cox AR. Paracrine signaling in islet function and survival. J Mol Med (Berl) 2020; 98:451-467. [PMID: 32067063 DOI: 10.1007/s00109-020-01887-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/05/2020] [Accepted: 02/11/2020] [Indexed: 02/06/2023]
Abstract
The pancreatic islet is a dense cellular network comprised of several cell types with endocrine function vital in the control of glucose homeostasis, metabolism, and feeding behavior. Within the islet, endocrine hormones also form an intricate paracrine network with supportive cells (endothelial, neuronal, immune) and secondary signaling molecules regulating cellular function and survival. Modulation of these signals has potential consequences for diabetes development, progression, and therapeutic intervention. Beta cell loss, reduced endogenous insulin secretion, and dysregulated glucagon secretion are hallmark features of both type 1 and 2 diabetes that not only impact systemic regulation of glucose, but also contribute to the function and survival of cells within the islet. Advancing research and technology have revealed new islet biology (cellular identity and transcriptomes) and identified previously unrecognized paracrine signals and mechanisms (somatostatin and ghrelin paracrine actions), while shifting prior views of intraislet communication. This review will summarize the paracrine signals regulating islet endocrine function and survival, the disruption and dysfunction that occur in diabetes, and potential therapeutic targets to preserve beta cell mass and function.
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Affiliation(s)
- Sean M Hartig
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Aaron R Cox
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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19
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Grandl G, Novikoff A, DiMarchi R, Tschöp MH, Müller TD. Gut Peptide Agonism in the Treatment of Obesity and Diabetes. Compr Physiol 2019; 10:99-124. [PMID: 31853954 DOI: 10.1002/cphy.c180044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Obesity is a global healthcare challenge that gives rise to devastating diseases such as the metabolic syndrome, type-2 diabetes (T2D), and a variety of cardiovascular diseases. The escalating prevalence of obesity has led to an increased interest in pharmacological options to counteract excess weight gain. Gastrointestinal hormones such as glucagon, amylin, and glucagon-like peptide-1 (GLP-1) are well recognized for influencing food intake and satiety, but the therapeutic potential of these native peptides is overall limited by a short half-life and an often dose-dependent appearance of unwanted effects. Recent clinical success of chemically optimized GLP-1 mimetics with improved pharmacokinetics and sustained action has propelled pharmacological interest in using bioengineered gut hormones to treat obesity and diabetes. In this article, we summarize the basic biology and signaling mechanisms of selected gut peptides and discuss how they regulate systemic energy and glucose metabolism. Subsequently, we focus on the design and evaluation of unimolecular drugs that combine the beneficial effects of selected gut hormones into a single entity to optimize the beneficial impact on systems metabolism. © 2020 American Physiological Society. Compr Physiol 10:99-124, 2020.
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Affiliation(s)
- Gerald Grandl
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Aaron Novikoff
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Richard DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Matthias H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany.,Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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20
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Müller TD, Finan B, Bloom SR, D'Alessio D, Drucker DJ, Flatt PR, Fritsche A, Gribble F, Grill HJ, Habener JF, Holst JJ, Langhans W, Meier JJ, Nauck MA, Perez-Tilve D, Pocai A, Reimann F, Sandoval DA, Schwartz TW, Seeley RJ, Stemmer K, Tang-Christensen M, Woods SC, DiMarchi RD, Tschöp MH. Glucagon-like peptide 1 (GLP-1). Mol Metab 2019; 30:72-130. [PMID: 31767182 PMCID: PMC6812410 DOI: 10.1016/j.molmet.2019.09.010] [Citation(s) in RCA: 859] [Impact Index Per Article: 171.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/10/2019] [Accepted: 09/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - B Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - S R Bloom
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - D D'Alessio
- Division of Endocrinology, Duke University Medical Center, Durham, NC, USA
| | - D J Drucker
- The Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Ontario, M5G1X5, Canada
| | - P R Flatt
- SAAD Centre for Pharmacy & Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - A Fritsche
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - F Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - H J Grill
- Institute of Diabetes, Obesity and Metabolism, Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - J J Meier
- Diabetes Division, St Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M A Nauck
- Diabetes Center Bochum-Hattingen, St Josef Hospital (Ruhr-Universität Bochum), Bochum, Germany
| | - D Perez-Tilve
- Department of Internal Medicine, University of Cincinnati-College of Medicine, Cincinnati, OH, USA
| | - A Pocai
- Cardiovascular & ImmunoMetabolism, Janssen Research & Development, Welsh and McKean Roads, Spring House, PA, 19477, USA
| | - F Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - D A Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - T W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DL-2200, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - M Tang-Christensen
- Obesity Research, Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | - S C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - R D DiMarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany; Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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21
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Tomas A, Jones B, Leech C. New Insights into Beta-Cell GLP-1 Receptor and cAMP Signaling. J Mol Biol 2019; 432:1347-1366. [PMID: 31446075 DOI: 10.1016/j.jmb.2019.08.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/06/2019] [Accepted: 08/13/2019] [Indexed: 12/14/2022]
Abstract
Harnessing the translational potential of the GLP-1/GLP-1R system in pancreatic beta cells has led to the development of established GLP-1R-based therapies for the long-term preservation of beta cell function. In this review, we discuss recent advances in the current research on the GLP-1/GLP-1R system in beta cells, including the regulation of signaling by endocytic trafficking as well as the application of concepts such as signal bias, allosteric modulation, dual agonism, polymorphic receptor variants, spatial compartmentalization of cAMP signaling and new downstream signaling targets involved in the control of beta cell function.
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Affiliation(s)
- Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 0NN, UK.
| | - Ben Jones
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Colin Leech
- Department of Surgery, State University of New York, Upstate Medical University, Syracuse, NY, 13210, USA
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22
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Sarmiento BE, Santos Menezes LF, Schwartz EF. Insulin Release Mechanism Modulated by Toxins Isolated from Animal Venoms: From Basic Research to Drug Development Prospects. Molecules 2019; 24:E1846. [PMID: 31091684 PMCID: PMC6571724 DOI: 10.3390/molecules24101846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/23/2019] [Accepted: 05/09/2019] [Indexed: 12/12/2022] Open
Abstract
Venom from mammals, amphibians, snakes, arachnids, sea anemones and insects provides diverse sources of peptides with different potential medical applications. Several of these peptides have already been converted into drugs and some are still in the clinical phase. Diabetes type 2 is one of the diseases with the highest mortality rate worldwide, requiring specific attention. Diverse drugs are available (e.g., Sulfonylureas) for effective treatment, but with several adverse secondary effects, most of them related to the low specificity of these compounds to the target. In this context, the search for specific and high-affinity compounds for the management of this metabolic disease is growing. Toxins isolated from animal venom have high specificity and affinity for different molecular targets, of which the most important are ion channels. This review will present an overview about the electrical activity of the ion channels present in pancreatic β cells that are involved in the insulin secretion process, in addition to the diversity of peptides that can interact and modulate the electrical activity of pancreatic β cells. The importance of prospecting bioactive peptides for therapeutic use is also reinforced.
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Affiliation(s)
- Beatriz Elena Sarmiento
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
| | - Luis Felipe Santos Menezes
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
| | - Elisabeth F Schwartz
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
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23
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Sun ZL, Jiang XF, Cheng YC, Liu YF, Yang K, Zhu SL, Kong XB, Tu Y, Bian KF, Liu ZL, Chen XY. Exendin-4 inhibits high-altitude cerebral edema by protecting against neurobiological dysfunction. Neural Regen Res 2018; 13:653-663. [PMID: 29722317 PMCID: PMC5950675 DOI: 10.4103/1673-5374.230291] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The anti-inflammatory and antioxidant effects of exendin-4 (Ex-4) have been reported previously. However, whether (Ex-4) has anti-inflammatory and antioxidant effects on high-altitude cerebral edema (HACE) remains poorly understood. In this study, two rat models of HACE were established by placing rats in a hypoxic environment with a simulated altitude of either 6000- or 7000-m above sea level (MASL) for 72 hours. An altitude of 7000 MASL with 72-hours of hypoxia was found to be the optimized experimental paradigm for establishing HACE models. Then, in rats where a model of HACE was established by introducing them to a 7000 MASL environment with 72-hours of hypoxia treatment, 2, 10 and, 100 μg of Ex-4 was intraperitoneally administrated. The open field test and tail suspension test were used to test animal behavior. Routine methods were used to detect change in inflammatory cells. Hematoxylin-eosin staining was performed to determine pathological changes to brain tissue. Wet/dry weight ratios were used to measure brain water content. Evans blue leakage was used to determine blood-brain barrier integrity. Enzyme-linked immunosorbent assay (ELISA) was performed to measure markers of inflammation and oxidative stress including superoxide dismutase, glutathione, and malonaldehyde values, as well as interleukin-6, tumor necrosis factor-alpha, cyclic adenosine monophosphate levels in the brain tissue. Western blot analysis was performed to determine the levels of occludin, ZO-1, SOCS-3, vascular endothelial growth factor, EPAC1, nuclear factor-kappa B, and aquaporin-4. Our results demonstrate that Ex-4 preconditioning decreased brain water content, inhibited inflammation and oxidative stress, alleviated brain tissue injury, maintain blood-brain barrier integrity, and effectively improved motor function in rat models of HACE. These findings suggest that Ex-4 exhibits therapeutic potential in the treatment of HACE.
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Affiliation(s)
- Zhong-Lei Sun
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces, Institute of Traumatic Brain Trauma and Neurological of CAPF, Neurotrauma Repair Key Laboratory of Tianjin, Tianjin; Jinzhou Medical University, Jinzhou, Liaoning Province, China
| | - Xian-Feng Jiang
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces, Institute of Traumatic Brain Trauma and Neurological of CAPF, Neurotrauma Repair Key Laboratory of Tianjin; Tianjin Medical University, Tianjin, China
| | - Yuan-Chi Cheng
- Central Hospital of Fengxian District of Shanghai, Shanghai, China
| | - Ying-Fu Liu
- Logistics University of People's Armed Police Force, Tianjin, China
| | - Kai Yang
- The No. 2 Hospital of Nanjing, Nanjing, Jiangsu Province, China
| | | | - Xian-Bin Kong
- Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Yue Tu
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces, Institute of Traumatic Brain Trauma and Neurological of CAPF, Neurotrauma Repair Key Laboratory of Tianjin, Tianjin, China
| | - Ke-Feng Bian
- Logistics University of People's Armed Police Force, Tianjin, China
| | - Zhen-Lin Liu
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces, Institute of Traumatic Brain Trauma and Neurological of CAPF, Neurotrauma Repair Key Laboratory of Tianjin, Tianjin, China
| | - Xu-Yi Chen
- Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces, Institute of Traumatic Brain Trauma and Neurological of CAPF, Neurotrauma Repair Key Laboratory of Tianjin, Tianjin, China
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24
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Matsumura K, Tamasawa N, Daimon M. Possible Insulinotropic Action of Apolipoprotein A-I Through the ABCA1/Cdc42/cAMP/PKA Pathway in MIN6 Cells. Front Endocrinol (Lausanne) 2018; 9:645. [PMID: 30425683 PMCID: PMC6218629 DOI: 10.3389/fendo.2018.00645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/11/2018] [Indexed: 01/07/2023] Open
Abstract
Aims/Introduction: We studied the mechanisms for the possible insulinotropic action of apolipoprotein (Apo) A-I in mouse insulinoma (MIN6) cells. Materials and Methods: The effects of ApoA-I on cAMP production and glucose-stimulated insulin secretion (GSIS), and the dose dependency (ApoA-I at 5, 10, 25, and 50 μg/ml) were determined using MIN6 cells. The effects of the small-interference ribonucleic acid (siRNA) of ATP-binding cassette transporter A1(ABCA1) and Cell division control protein 42 homolog (Cdc42) on the insulinotropic action of ApoA-I was studied, as well as mRNA and protein levels of ABCA1 and Cdc42. Then, the influence of cAMP inhibitor SQ22536, and the cAMP-dependent protein kinase inhibitor Rp-cAMPS on ApoA-I action were studied. Results: Addition of ApoA-I produced cAMP and increased insulin secretion, dose-dependently in high glucose concentration (25 mmmol/l). and ABCA1 protein and Cdc42 mRNA and protein were also enhanced. Specific ABCA1 and Cdc42 siRNA significantly decreased the effects of ApoA-I on insulin secretion compared with negative controls. Manifestations of ABCA1 and Cdc42 mRNA and protein were less than that of the negative control group. Both cAMP inhibiror (SQ22536) and protein kinases inhibitor (Rp-cAMPS) strongly inhibited the effects of ApoA-I on insulin secretion. Conclusions: We demonstrated that ApoA-I enhances glucose-stimulated insulin release in high glucose at least partially through the ABCA1/Cdc42/cAMP/ Protein kinase A (PKA) pathway.
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Affiliation(s)
- Koki Matsumura
- Graduate School of Medicine and School of Medicine, Hirosaki University, Hirosaki, Japan
- *Correspondence: Koki Matsumura
| | | | - Makoto Daimon
- Graduate School of Medicine and School of Medicine, Hirosaki University, Hirosaki, Japan
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25
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Medras ZJH, El-Sayed NM, Zaitone SA, Toraih EA, Sami MM, Moustafa YM. Glutamine up-regulates pancreatic sodium-dependent neutral aminoacid transporter-2 and mitigates islets apoptosis in diabetic rats. Pharmacol Rep 2017; 70:233-242. [PMID: 29475006 DOI: 10.1016/j.pharep.2017.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/24/2017] [Accepted: 10/24/2017] [Indexed: 01/09/2023]
Abstract
BACKGROUND Glutamine aminoacid regulates insulin exocytosis from pancreatic β-cells. Liraglutide is a glucagon-like peptide-1 (GLP-1) analogue that has fascinated function in inhibiting β-cell apoptosis and preserving pancreatic β-cell mass. The present study investigated the benefit of adding glutamine to a regimen of liraglutide in diabetic rats focusing on their role in increasing insulin production and upregulation of the expression of sodium-dependent neutral aminoacid transporter-2 (SNAT2). METHODS In the present study, diabetes mellitus was induced in rats using streptozotocin (STZ, 50mg/kg, ip). Male rats were allocated into 5 groups, (i) vehicle group, (ii) STZ-diabetic rats, (iii) STZ-diabetic rats treated with liraglutide (150μg/kg, sc), (iv) STZ-diabetic rats treated with glutamine (po) and (v) STZ-diabetic rats treated with a combination of liraglutide and glutamine for four weeks. After finishing the therapeutic courses, the fasting blood glucose value was determined and rats were sacrificed. Pancreases were used for quantification of mRNA expression for SNAT2. Paraffin fixed samples were used for histologic staining and immunohistochemistry for insulin and apoptosis markers (activated caspase-3, BCL2 and BAX). RESULTS Treatment with liraglutide and/or glutamine enhanced insulin production and hence glycemic control in diabetic male rats with favorable effects on apoptosis markers. Treatment with glutamine and its combination with liraglutide significantly increased pancreatic expression of SNAT2 by approximately 30-35 folds. CONCLUSION Addition of glutamine to liraglutide regimen enhances the glycemic control and may have utility in clinical settings.
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Affiliation(s)
| | - Norhan M El-Sayed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
| | - Sawsan A Zaitone
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt; Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia.
| | - Eman A Toraih
- Genetics Unit, Department of Histology and Cell Biology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Manal M Sami
- Department of Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Yasser M Moustafa
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt
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26
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GLP-1/Exendin-4 induces β-cell proliferation via the epidermal growth factor receptor. Sci Rep 2017; 7:9100. [PMID: 28831150 PMCID: PMC5567347 DOI: 10.1038/s41598-017-09898-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/31/2017] [Indexed: 01/21/2023] Open
Abstract
Exendin-4 is a long acting glucagon-like peptide 1 (GLP-1) analogue that is an agonist for the GLP-1 receptor, a G-protein coupled receptor (GPCR). Exendin-4 is used to clinically improve glucose tolerance in diabetic patients due to its ability to enhance insulin secretion. In rodents, and possibly in humans, exendin-4 can stimulate β-cell proliferation. The exact mechanism of action to induce β-cell proliferation is not well understood. Here, using a β-cell specific epidermal growth factor receptor (EGFR) null mouse, we show that exendin-4 induced an increase in proliferation and β-cell mass through EGFR. Thus, our study sheds light on the role of EGFR signaling in the effects of exendin-4 on the control of blood glucose metabolism and β-cell mass.
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27
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Müller TD, Finan B, Clemmensen C, DiMarchi RD, Tschöp MH. The New Biology and Pharmacology of Glucagon. Physiol Rev 2017; 97:721-766. [PMID: 28275047 DOI: 10.1152/physrev.00025.2016] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the last two decades we have witnessed sizable progress in defining the role of gastrointestinal signals in the control of glucose and energy homeostasis. Specifically, the molecular basis of the huge metabolic benefits in bariatric surgery is emerging while novel incretin-based medicines based on endogenous hormones such as glucagon-like peptide 1 and pancreas-derived amylin are improving diabetes management. These and related developments have fostered the discovery of novel insights into endocrine control of systemic metabolism, and in particular a deeper understanding of the importance of communication across vital organs, and specifically the gut-brain-pancreas-liver network. Paradoxically, the pancreatic peptide glucagon has reemerged in this period among a plethora of newly identified metabolic macromolecules, and new data complement and challenge its historical position as a gut hormone involved in metabolic control. The synthesis of glucagon analogs that are biophysically stable and soluble in aqueous solutions has promoted biological study that has enriched our understanding of glucagon biology and ironically recruited glucagon agonism as a central element to lower body weight in the treatment of metabolic disease. This review summarizes the extensive historical record and the more recent provocative direction that integrates the prominent role of glucagon in glucose elevation with its under-acknowledged effects on lipids, body weight, and vascular health that have implications for the pathophysiology of metabolic diseases, and the emergence of precision medicines to treat metabolic diseases.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - B Finan
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - C Clemmensen
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - R D DiMarchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
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28
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Graaf CD, Donnelly D, Wootten D, Lau J, Sexton PM, Miller LJ, Ahn JM, Liao J, Fletcher MM, Yang D, Brown AJH, Zhou C, Deng J, Wang MW. Glucagon-Like Peptide-1 and Its Class B G Protein-Coupled Receptors: A Long March to Therapeutic Successes. Pharmacol Rev 2017; 68:954-1013. [PMID: 27630114 PMCID: PMC5050443 DOI: 10.1124/pr.115.011395] [Citation(s) in RCA: 219] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain-binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders.
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Affiliation(s)
- Chris de Graaf
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Dan Donnelly
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Denise Wootten
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jesper Lau
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Patrick M Sexton
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Laurence J Miller
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jung-Mo Ahn
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jiayu Liao
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Madeleine M Fletcher
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Dehua Yang
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Alastair J H Brown
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Caihong Zhou
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Jiejie Deng
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
| | - Ming-Wei Wang
- Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands (C.d.G.); School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom (D.D.); Drug Discovery Biology Theme and Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia (D.W., P.M.S., M.M.F.); Protein and Peptide Chemistry, Global Research, Novo Nordisk A/S, Måløv, Denmark (J.La.); Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, Arizona (L.J.M.); Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas (J.-M.A.); Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, Riverside, California (J.Li.); National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China (D.Y., C.Z., J.D., M.-W.W.); Heptares Therapeutics, BioPark, Welwyn Garden City, United Kingdom (A.J.H.B.); and School of Pharmacy, Fudan University, Zhangjiang High-Tech Park, Shanghai, China (M.-W.W.)
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29
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Liu Y, Zhong X, Ding Y, Ren L, Bai T, Liu M, Liu Z, Guo Y, Guo Q, Zhang Y, Yang J, Zhang Y. Inhibition of voltage-dependent potassium channels mediates cAMP-potentiated insulin secretion in rat pancreatic β cells. Islets 2017; 9:11-18. [PMID: 28103136 PMCID: PMC5345751 DOI: 10.1080/19382014.2017.1280644] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Insulin secretion is essential for maintenance of glucose homeostasis. An important intracellular signal regulating insulin secretion is cAMP. In this report, we showed that an increase of cAMP induced by adenylyl cyclase (AC) activator forskolin or by cAMP analog db-cAMP not only potentiated insulin secretion but also inhibited Kv channels, and these effects were reversed by AC inhibitor SQ22536. The cAMP-mediated Kv channel inhibition resulted in prolongation of action potential duration, which partly accounts for the elevation of intracellular Ca2+ induced by activation of cAMP signaling. Taken together, the results suggest that Kv channels are involved in cAMP-potentiated insulin secretion in pancreatic β cells.
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Affiliation(s)
- Yunfeng Liu
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
- CONTACT Yunfeng Liu Department of Endocrinology, The first Hospital of Shanxi Medical University, Taiyuan 030001, China; Yi Zhang , Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China
| | - Xiangqin Zhong
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yaqin Ding
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Lele Ren
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Tao Bai
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Mengmeng Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Zhihong Liu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
| | - Yangyan Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Yu Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
| | - Jing Yang
- Department of Endocrinology, the First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China
| | - Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China
- Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, China
- CONTACT Yunfeng Liu Department of Endocrinology, The first Hospital of Shanxi Medical University, Taiyuan 030001, China; Yi Zhang , Department of Pharmacology, Shanxi Medical University, Taiyuan 030001, China
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30
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Kakei M, Yoshida M, Dezaki K, Ito K, Yamada H, Funazaki S, Kawakami M, Sugawara H, Yada T. Glucose and GTP-binding protein-coupled receptor cooperatively regulate transient receptor potential-channels to stimulate insulin secretion [Review]. Endocr J 2016; 63:867-876. [PMID: 27321586 DOI: 10.1507/endocrj.ej16-0262] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In pancreatic β-cells, glucose-induced closure of the ATP-sensitive K+ (KATP) channel is an initial process triggering glucose-stimulated insulin secretion (GSIS). This KATP-channel dependent pathway has been believed to be a central mechanism for GSIS. However, since the resting membrane potential of cells is determined by the balance of the net result of current amplitudes in outward and inward directions, it must be taken into consideration that not only KATP channel inhibition but also inward current via the basal opening of non-selective cation channels (NSCCs) plays a crucial role in membrane potential regulation. The basal activity of NSCCs is essential to effectively evoke depolarization in concert with KATP channel closure that is dependent on glucose metabolism. The present study summarizes recent findings regarding the roles of NSCCs in GSIS and GTP-binding protein coupled receptor-(GPCR) operated potentiation of GSIS.
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Affiliation(s)
- Masafumi Kakei
- Internal Medicine, Saitama Medical Center, Jichi Medical University, Saitama 330-8503, Japan
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31
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Liu J, Pang ZP. Glucagon-like peptide-1 drives energy metabolism on the synaptic highway. FEBS J 2016; 283:4413-4423. [DOI: 10.1111/febs.13785] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/04/2016] [Accepted: 06/16/2016] [Indexed: 01/17/2023]
Affiliation(s)
- Ji Liu
- Child Health Institute of New Jersey; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
- Department of Neuroscience and Cell Biology; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
| | - Zhiping P. Pang
- Child Health Institute of New Jersey; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
- Department of Neuroscience and Cell Biology; Rutgers University Robert Wood Johnson Medical School; New Brunswick NJ USA
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32
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Thiebaud N, Llewellyn-Smith IJ, Gribble F, Reimann F, Trapp S, Fadool DA. The incretin hormone glucagon-like peptide 1 increases mitral cell excitability by decreasing conductance of a voltage-dependent potassium channel. J Physiol 2016; 594:2607-28. [PMID: 26931093 PMCID: PMC4865572 DOI: 10.1113/jp272322] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/25/2016] [Indexed: 02/06/2023] Open
Abstract
Key points The gut hormone called glucagon‐like peptide 1 (GLP‐1) is a strong moderator of energy homeostasis and communication between the peripheral organs and the brain. GLP‐1 signalling occurs in the brain; using a newly developed genetic reporter line of mice, we have discovered GLP‐synthesizing cells in the olfactory bulb. GLP‐1 increases the firing frequency of neurons (mitral cells) that encode olfactory information by decreasing activity of voltage‐dependent K channels (Kv1.3). Modifying GLP‐1 levels, either therapeutically or following the ingestion of food, could alter the excitability of neurons in the olfactory bulb in a nutrition or energy state‐dependent manner to influence olfactory detection or metabolic sensing. The results of the present study uncover a new function for an olfactory bulb neuron (deep short axon cells, Cajal cells) that could be capable of modifying mitral cell activity through the release of GLP‐1. This might be of relevance for the action of GLP‐1 mimetics now widely used in the treatment of diabetes.
Abstract The olfactory system is intricately linked with the endocrine system where it may serve as a detector of the internal metabolic state or energy homeostasis in addition to its classical function as a sensor of external olfactory information. The recent development of transgenic mGLU‐yellow fluorescent protein mice that express a genetic reporter under the control of the preproglucagon reporter suggested the presence of the gut hormone, glucagon‐like peptide (GLP‐1), in deep short axon cells (Cajal cells) of the olfactory bulb and its neuromodulatory effect on mitral cell (MC) first‐order neurons. A MC target for the peptide was determined using GLP‐1 receptor binding assays, immunocytochemistry for the receptor and injection of fluorescence‐labelled GLP‐1 analogue exendin‐4. Using patch clamp recording of olfactory bulb slices in the whole‐cell configuration, we report that GLP‐1 and its stable analogue exendin‐4 increase the action potential firing frequency of MCs by decreasing the interburst interval rather than modifying the action potential shape, train length or interspike interval. GLP‐1 decreases Kv1.3 channel contribution to outward currents in voltage clamp recordings as determined by pharmacological blockade of Kv1.3 or utilizing mice with Kv1.3 gene‐targeted deletion as a negative control. Because fluctuations in GLP‐1 concentrations monitored by the olfactory bulb can modify the firing frequency of MCs, olfactory coding could change depending upon nutritional or physiological state. As a regulator of neuronal activity, GLP‐1 or its analogue may comprise a new metabolic factor with a potential therapeutic target in the olfactory bulb (i.e. via intranasal delivery) for controlling an imbalance in energy homeostasis. The gut hormone called glucagon‐like peptide 1 (GLP‐1) is a strong moderator of energy homeostasis and communication between the peripheral organs and the brain. GLP‐1 signalling occurs in the brain; using a newly developed genetic reporter line of mice, we have discovered GLP‐synthesizing cells in the olfactory bulb. GLP‐1 increases the firing frequency of neurons (mitral cells) that encode olfactory information by decreasing activity of voltage‐dependent K channels (Kv1.3). Modifying GLP‐1 levels, either therapeutically or following the ingestion of food, could alter the excitability of neurons in the olfactory bulb in a nutrition or energy state‐dependent manner to influence olfactory detection or metabolic sensing. The results of the present study uncover a new function for an olfactory bulb neuron (deep short axon cells, Cajal cells) that could be capable of modifying mitral cell activity through the release of GLP‐1. This might be of relevance for the action of GLP‐1 mimetics now widely used in the treatment of diabetes.
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Affiliation(s)
- Nicolas Thiebaud
- The Florida State University, Department of Biological Science, Program in Neuroscience, Tallahassee, FL, USA
| | - Ida J Llewellyn-Smith
- Cardiovascular Medicine and Human Physiology, School of Medicine, Flinders University, Bedford Park, SA, Australia
| | - Fiona Gribble
- Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, UK
| | - Frank Reimann
- Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, UK
| | - Stefan Trapp
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK.,Department of Surgery and Cancer, Imperial College London, London, UK
| | - Debra Ann Fadool
- The Florida State University, Department of Biological Science, Program in Neuroscience, Tallahassee, FL, USA.,The Florida State University, Institute of Molecular Biophysics, Tallahassee, FL, USA
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33
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The complexity of signalling mediated by the glucagon-like peptide-1 receptor. Biochem Soc Trans 2016; 44:582-8. [DOI: 10.1042/bst20150244] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Indexed: 01/14/2023]
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) is a class B GPCR that is a major therapeutic target for the treatment of type 2 diabetes. The receptor is activated by the incretin peptide GLP-1 promoting a broad range of physiological effects including glucose-dependent insulin secretion and biosynthesis, improved insulin sensitivity of peripheral tissues, preservation of β-cell mass and weight loss, all of which are beneficial in the treatment of type 2 diabetes. Despite this, existing knowledge surrounding the underlying signalling mechanisms responsible for the physiological actions downstream of GLP-1R activation is limited. Here, we review the current understanding around GLP-1R-mediated signalling, in particular highlighting recent contributions to the field on biased agonism, the spatial and temporal aspects for the control of signalling and how these concepts may influence future drug development.
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34
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Abstract
Type 2 diabetes is a complex disease. It results from a failure of the body to maintain energy homoeostasis. Multicellular organisms have evolved complex strategies to preserve a relatively stable internal nutrient environment, despite fluctuations in external nutrient availability. This complex strategy involves the co-ordinated responses of multiple organs to promote storage or mobilization of energy sources according to the availability of nutrients and cellular bioenergetics needs. The endocrine pancreas plays a central role in these processes by secreting insulin and glucagon. When this co-ordinated effort fails, hyperglycaemia and hyperlipidaemia develops, characterizing a state of metabolic imbalance and ultimately overt diabetes. Although diabetes is most likely a collection of diseases, scientists are starting to identify genetic components and environmental triggers. Genome-wide association studies revealed that by and large, gene variants associated with type 2 diabetes are implicated in pancreatic β-cell function, suggesting that the β-cell may be the weakest link in the chain of events that results in diabetes. Thus, it is critical to understand how environmental cues affect the β-cell. Phosphoinositides are important 'decoders' of environmental cues. As such, these lipids have been implicated in cellular responses to a wide range of growth factors, hormones, stress agents, nutrients and metabolites. Here we will review some of the well-established and potential new roles for phosphoinositides in β-cell function/dysfunction and discuss how our knowledge of phosphoinositide signalling could aid in the identification of potential strategies for treating or preventing type 2 diabetes.
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Affiliation(s)
- Lucia E Rameh
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, U.S.A.
| | - Jude T Deeney
- Department of Medicine, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, U.S.A
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35
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Gleizes C, Kreutter G, Abbas M, Kassem M, Constantinescu AA, Boisramé-Helms J, Yver B, Toti F, Kessler L. β cell membrane remodelling and procoagulant events occur in inflammation-driven insulin impairment: a GLP-1 receptor dependent and independent control. J Cell Mol Med 2015; 20:231-42. [PMID: 26607759 PMCID: PMC4727568 DOI: 10.1111/jcmm.12683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 08/14/2015] [Indexed: 01/11/2023] Open
Abstract
Inflammation and hyperglycaemia are associated with a prothrombotic state. Cell-derived microparticles (MPs) are the conveyors of active procoagulant tissue factor (TF) and circulate at high concentration in diabetic patients. Liraglutide, a glucagon-like peptide (GLP)-1 analogue, is known to promote insulin secretion and β-cell preservation. In this in vitro study, we examined the link between insulin impairment, procoagulant activity and plasma membrane remodelling, under inflammatory conditions. Rin-m5f β-cell function, TF activity mediated by MPs and their modulation by 1 μM liraglutide were examined in a cell cross-talk model. Methyl-β-cyclodextrine (MCD), a cholesterol depletor, was used to evaluate the involvement of raft on TF activity, MP shedding and insulin secretion as well as Soluble N-éthylmaleimide-sensitive-factor Attachment protein Receptor (SNARE)-dependent exocytosis. Cytokines induced a two-fold increase in TF activity at MP surface that was counteracted by liraglutide. Microparticles prompted TF activity on the target cells and a two-fold decrease in insulin secretion via protein kinase A (PKA) and p38 signalling, that was also abolished by liraglutide. Large lipid raft clusters were formed in response to cytokines and liraglutide or MCD-treated cells showed similar patterns. Cells pre-treated by saturating concentration of the GLP-1r antagonist exendin (9-39), showed a partial abolishment of the liraglutide-driven insulin secretion and liraglutide-decreased TF activity. Measurement of caspase 3 cleavage and MP shedding confirmed the contribution of GLP-1r-dependent and -independent pathways. Our results confirm an integrative β-cell response to GLP-1 that targets receptor-mediated signalling and membrane remodelling pointing at the coupling of insulin secretion and inflammation-driven procoagulant events.
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Affiliation(s)
- Céline Gleizes
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France.,Federation of Translational Medicine of Strasbourg, Faculty of Medicine, University of Strasbourg, Strasbourg, France
| | - Guillaume Kreutter
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France.,Federation of Translational Medicine of Strasbourg, Faculty of Medicine, University of Strasbourg, Strasbourg, France
| | - Malak Abbas
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France.,Doctoral School of Sciences and Technologies, Lebanese University, Beiruth-Hadath, Lebanon
| | - Mohamad Kassem
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France
| | - Andrei Alexandru Constantinescu
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France.,Department of Parasitology and Parasitic Diseases and Animal Biology, Faculty of Veterinary Medicine, University of Agronomical Sciences and Veterinary Medicine, Bucharest, Romania
| | - Julie Boisramé-Helms
- Department of Reanimation, Nouvel hopital civil, Strasbourg CEDEX, France.,Federation of Translational Medicine of Strasbourg, Faculty of Medicine, University of Strasbourg, Strasbourg, France
| | - Blandine Yver
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France
| | - Florence Toti
- UMR7213 CNRS, Laboratory of Biophotonics and Pharmacology, Faculty of Pharmacy, University of Strasbourg, Illkirch, France
| | - Laurence Kessler
- EA7293, Vascular and Tissular Stress in Transplantation, Faculty of Medicine, University of Strasbourg, Illkirch, France.,Federation of Translational Medicine of Strasbourg, Faculty of Medicine, University of Strasbourg, Strasbourg, France.,Department of Diabetology, University Hospital, Strasbourg Cedex, France
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36
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Abstract
The ability of glucose to stimulate insulin secretion from the pancreatic islets of Langerhans is enhanced by the intestinal hormone glucagon-like peptide 1 (GLP-1), which is secreted from the gut in response to nutrient ingestion. This action, called the incretin effect, accounts for as much as half of the postprandial insulin response and is exploited therapeutically for diabetes treatment through the use of incretin mimetic drugs and inhibitors of dipeptidyl peptidase 4, which degrades GLP-1. Despite a prominent role for incretin mimetics in diabetes treatment, several key questions remain about GLP-1-induced insulin secretion. Most studies have examined the effects of GLP-1 at concentrations several orders of magnitude higher than those found in vivo; therefore, one might question the physiological (and perhaps even pharmacological) relevance of pathways identified in these studies and whether other important mechanisms might have been obscured. In this issue of the JCI, Shigeto and colleagues demonstrate that physiological GLP-1 does indeed amplify the insulin secretory response. Intriguingly, while much of this response is PKA dependent, as might be expected, the use of picomolar GLP-1 reveals a new and important mechanism that contributes to GLP-1-induced insulin secretion.
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37
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Zhang Y, Wang H, Guo Q, Li X, Gao J, Liu Y, Yang C, Niu L, Yang J. PI3K is involved in P2Y receptor-regulated cAMP /Epac/Kv channel signaling pathway in pancreatic β cells. Biochem Biophys Res Commun 2015; 465:714-8. [PMID: 26296468 DOI: 10.1016/j.bbrc.2015.08.057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 12/20/2022]
Abstract
P2Y receptors (P2YR) are a family of purinergic G protein-coupled receptors, which could be stimulated by extracellular nucleotides. In pancreatic β cells, activation of P2YR has long been shown to stimulate insulin secretion in a glucose-dependent manner. Previously, we reported that P2YR-modulated insulin secretion is mediated by a cAMP/Epac/Kv channel pathway. However, the interaction between Epac and the Kv channel in P2YR-modulated insulin secretion remains unclear. In this study, we used patch-clamp technique and insulin secretion assay to investigate the potential molecules that may link Epac to Kv channel inhibition induced by P2YR activation. We identified that phosphatidylinositide 3-kinase, which mediates P2YR-regulated insulin secretion, is a critical mediator between Epac and the Kv channel.
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Affiliation(s)
- Yi Zhang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Hui Wang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Qing Guo
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Xiaodong Li
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Jingying Gao
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Yunfeng Liu
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
| | - Caihong Yang
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Longgang Niu
- Department of Pharmacology, Shanxi Medical University, Taiyuan, China.
| | - Jing Yang
- Department of Endocrinology, The First Hospital of Shanxi Medical University, Shanxi Medical University, Taiyuan, China.
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Sukma Rita R, Dezaki K, Kurashina T, Kakei M, Yada T. Partial blockade of Kv2.1 channel potentiates GLP-1's insulinotropic effects in islets and reduces its dose required for improving glucose tolerance in type 2 diabetic male mice. Endocrinology 2015; 156:114-23. [PMID: 25337656 DOI: 10.1210/en.2014-1728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucagon-like peptide-1 (GLP-1)-based medicines have recently been widely used to treat type 2 diabetic patients, whereas adverse effects of nausea and vomiting have been documented. Inhibition of voltage-gated K(+) channel subtype Kv2.1 in pancreatic β-cells has been suggested to contribute to mild depolarization and promotion of insulin release. This study aimed to determine whether the blockade of Kv2.1 channels potentiates the insulinotropic effect of GLP-1 agonists. Kv2.1 channel blocker guangxitoxin-1E (GxTx) and GLP-1 agonist exendin-4 at subthreshold concentrations, when combined, markedly increased the insulin release and cytosolic Ca(2+) concentration ([Ca(2+)]i) in a glucose-dependent manner in mouse islets and β-cells. Exendin-4 at subthreshold concentration alone increased islet insulin release and β-cell [Ca(2+)]i in Kv2.1(+/-) mice. The [Ca(2+)]i response to subthreshold exendin-4 and GxTx in combination was attenuated by pretreatment with protein kinase A inhibitor H-89, indicating the protein kinase A dependency of the cooperative effect. Furthermore, subthreshold doses of GxTx and GLP-1 agonist liraglutide in combination markedly increased plasma insulin and improved glucose tolerance in diabetic db/db mice and NSY mice. These results demonstrate that a modest suppression of Kv2.1 channels dramatically raises insulinotropic potency of GLP-1-based drugs, which opens a new avenue to reduce their doses and associated adverse effects while achieving the same glycemic control in type 2 diabetes.
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Affiliation(s)
- Rauza Sukma Rita
- Division of Integrative Physiology (R.S.R., K.D., T.K., T.Y.), Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan; Department of Internal Medicine (M.K.), Saitama Medical Center, Jichi Medical University School of Medicine, Saitama 337-8503, Japan; and Department of Development Physiology (T.Y.), Division of Adaptation Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
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Zhang M, Robitaille M, Showalter AD, Huang X, Liu Y, Bhattacharjee A, Willard FS, Han J, Froese S, Wei L, Gaisano HY, Angers S, Sloop KW, Dai FF, Wheeler MB. Progesterone receptor membrane component 1 is a functional part of the glucagon-like peptide-1 (GLP-1) receptor complex in pancreatic β cells. Mol Cell Proteomics 2014; 13:3049-62. [PMID: 25044020 DOI: 10.1074/mcp.m114.040196] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Glucagon-like peptide-1 (GLP-1) is an incretin hormone that regulates glucose homeostasis. Because of their direct stimulation of insulin secretion from pancreatic β cells, GLP-1 receptor (GLP-1R) agonists are now important therapeutic options for the treatment of type 2 diabetes. To better understand the mechanisms that control the insulinotropic actions of GLP-1, affinity purification and mass spectrometry (AP-MS) were employed to uncover potential proteins that functionally interact with the GLP-1R. AP-MS performed on Chinese hamster ovary cells or MIN6 β cells, both expressing the human GLP-1R, revealed 99 proteins potentially associated with the GLP-1R. Three novel GLP-1R interactors (PGRMC1, Rab5b, and Rab5c) were further validated through co-immunoprecipitation/immunoblotting, fluorescence resonance energy transfer, and immunofluorescence. Functional studies revealed that overexpression of PGRMC1, a novel cell surface receptor that associated with liganded GLP-1R, enhanced GLP-1-induced insulin secretion (GIIS) with the most robust effect. Knockdown of PGRMC1 in β cells decreased GIIS, indicative of positive interaction with GLP-1R. To gain insight mechanistically, we demonstrated that the cell surface PGRMC1 ligand P4-BSA increased GIIS, whereas its antagonist AG-205 decreased GIIS. It was then found that PGRMC1 increased GLP-1-induced cAMP accumulation. PGRMC1 activation and GIIS induced by P4-BSA could be blocked by inhibition of adenylyl cyclase/EPAC signaling or the EGF receptor-PI3K signal transduction pathway. These data reveal a dual mechanism for PGRMC1-increased GIIS mediated through cAMP and EGF receptor signaling. In conclusion, we identified several novel GLP-1R interacting proteins. PGRMC1 expressed on the cell surface of β cells was shown to interact with the activated GLP-1R to enhance the insulinotropic actions of GLP-1.
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Affiliation(s)
- Ming Zhang
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7
| | - Mélanie Robitaille
- ¶Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, and Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 3M2
| | - Aaron D Showalter
- ‖Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, 46285
| | - Xinyi Huang
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7
| | - Ying Liu
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8
| | - Alpana Bhattacharjee
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8
| | - Francis S Willard
- ‖‖Quantitative Biology, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, 46285
| | - Junfeng Han
- **Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China 200233
| | - Sean Froese
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7
| | - Li Wei
- **Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, China 200233
| | - Herbert Y Gaisano
- ‡‡Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8
| | - Stéphane Angers
- ¶Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, and Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 3M2
| | - Kyle W Sloop
- ‖Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, 46285
| | - Feihan F Dai
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8;
| | - Michael B Wheeler
- From the ‡Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada, M5S 1A8; §Division of Advanced Diagnosis, Toronto General Research Institute, Toronto, Canada, M5G 1C7;
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Abstract
Gastric inhibitory polypeptide (GIP) and glucagon‐like peptide‐1 (GLP‐1) are the two primary incretin hormones secreted from the intestine on ingestion of glucose or nutrients to stimulate insulin secretion from pancreatic β cells. GIP and GLP‐1 exert their effects by binding to their specific receptors, the GIP receptor (GIPR) and the GLP‐1 receptor (GLP‐1R), which belong to the G‐protein coupled receptor family. Receptor binding activates and increases the level of intracellular cyclic adenosine monophosphate in pancreatic β cells, thereby stimulating insulin secretion glucose‐dependently. In addition to their insulinotropic effects, GIP and GLP‐1 play critical roles in various biological processes in different tissues and organs that express GIPR and GLP‐1R, including the pancreas, fat, bone and the brain. Within the pancreas, GIP and GLP‐1 together promote β cell proliferation and inhibit apoptosis, thereby expanding pancreatic β cell mass, while GIP enhances postprandial glucagon response and GLP‐1 suppresses it. In adipose tissues, GIP but not GLP‐1 facilitates fat deposition. In bone, GIP promotes bone formation while GLP‐1 inhibits bone absorption. In the brain, both GIP and GLP‐1 are thought to be involved in memory formation as well as the control of appetite. In addition to these differences, secretion of GIP and GLP‐1 and their insulinotropic effects on β cells have been shown to differ in patients with type 2 diabetes compared to healthy subjects. We summarize here the similarities and differences of these two incretin hormones in secretion and metabolism, their insulinotropic action on pancreatic β cells, and their non‐insulinotropic effects, and discuss their potential in treatment of type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00022.x, 2010)
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Affiliation(s)
- Yutaka Seino
- The Division of Diabetes, Clinical Nutrition and Endocrinology, Kansai Electric Power Hospital, Osaka
| | - Mitsuo Fukushima
- The Division of Diabetes, Clinical Nutrition and Endocrinology, Kansai Electric Power Hospital, Osaka ; The Department of Nutritional Science, Okayama Prefectural University, Okayama, Japan
| | - Daisuke Yabe
- The Division of Diabetes, Clinical Nutrition and Endocrinology, Kansai Electric Power Hospital, Osaka
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Specific actions of GLP-1 receptor agonists and DPP4 inhibitors for the treatment of pancreatic β-cell impairments in type 2 diabetes. Cell Signal 2013; 25:570-9. [DOI: 10.1016/j.cellsig.2012.11.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 11/08/2012] [Indexed: 01/09/2023]
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Gigoux V, Fourmy D. Acting on Hormone Receptors with Minimal Side Effect on Cell Proliferation: A Timely Challenge Illustrated with GLP-1R and GPER. Front Endocrinol (Lausanne) 2013; 4:50. [PMID: 23641235 PMCID: PMC3638125 DOI: 10.3389/fendo.2013.00050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 04/10/2013] [Indexed: 12/18/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute a large family of receptors that sense molecules outside the cell and activate inside signal transduction pathways and cellular responses. GPCR are involved in a wide variety of physiological processes, including in the neuroendocrine system. GPCR are also involved in many diseases and are the target of 30% of marketed medicinal drugs. Whereas the majority of the GPCR-targeting drugs have proved their therapeutic benefit, some of them were associated with undesired effects. We develop two examples of used drugs whose therapeutic benefits are tarnished by carcinogenesis risks. The chronic administration of glucagon-like peptide-1 (GLP-1) analogs widely used to treat type-2 diabetes was associated with an increased risk of pancreatic or thyroid cancers. The long-term treatment with the estrogen antagonist tamoxifen, developed to target breast cancer overexpressing estrogen receptors ER, presents agonist activity on the G protein-coupled estrogen receptor which is associated with an increased incidence of endometrial cancer and breast cancer resistance to hormonotherapy. We point out and discuss the need of pharmacological studies to understand and overcome the undesired effects associated with the chronic administration of GPCR ligands. In fact, biological effects triggered by GPCR often result from the activation of multiple intracellular signaling pathways. Deciphering which signaling networks are engaged following GPCR activation appears to be primordial to unveil their contribution in the physiological and physiopathological processes. The development of biased agonists to elucidate the role of the different signaling mechanisms mediated by GPCR activation will allow the generation of new therapeutic agents with improved efficacy and reduced side effects. In this regard, the identification of GLP-1R biased ligands promoting insulin secretion without inducing pro-tumoral effects would offer therapeutic benefit.
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Affiliation(s)
- Véronique Gigoux
- Université de Toulouse, Université Paul SabatierToulouse, France
- *Correspondence: Véronique Gigoux, CHU Rangueil – INSERM, Université de Toulouse, Université Paul Sabatier, EA4552, 1 Avenue Jean Poulhès, BP 84225, 31432 Toulouse Cedex 4, France. e-mail:
| | - Daniel Fourmy
- Université de Toulouse, Université Paul SabatierToulouse, France
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Thulé PM. Mechanisms of current therapies for diabetes mellitus type 2. ADVANCES IN PHYSIOLOGY EDUCATION 2012; 36:275-83. [PMID: 23209008 PMCID: PMC3776431 DOI: 10.1152/advan.00094.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 09/21/2012] [Indexed: 06/12/2023]
Abstract
The array of medications available for the treatment of hyperglycemia has increased rapidly in the previous decade, and recent investigations have clarified novel mechanisms underlying the antihyperglycemic efficacy of these drugs. This article reviews the mechanisms of action for medications currently approved to treat diabetes mellitus in the United States, with the exception of insulin and its analogs. Finally, it attempts to integrate these mechanisms into the schema of pathophysiological factors that combine to produce hyperglycemia in patients with diabetes mellitus.
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Affiliation(s)
- Peter M Thulé
- Emory University School of Medicine, Decatur, Georgia, USA.
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Abstract
The new incretin-based therapies, dipeptidyl peptidase-4 (DPP4) inhibitors and glucagon like peptide 1 (GLP1) receptor agonists are widely used for the treatment of type 2 diabetes because of their glucose-lowering capacity with low risk of hypoglycemia. As they are weight neutral or induce weight loss in this mostly overweight population, they are popular among clinicians and patients alike. Nonetheless, concerns have been raised about GLP1's trophic effects. While increased β cell mass observed in rodents sounds appealing for treatment of diabetes, there was also an increased incidence of medullary thyroid cancer (MTC) in some species. We reviewed literature available in the Medline database until March 2012. Safety signals have emerged for MTC and pancreatic carcinoma from adverse event databases in the United States and Europe. Considering the relatively short duration of these studies, it is more likely that premalignant lesions are stimulated in presence of GLP1, rather than new neoplasms induced. Moreover, interpreting results of animal studies is difficult because of species-specific differences in presence and density of GLP1 receptors. Furthermore, data are emerging suggesting beneficial effects of GLP1 on colon and breast cancer. In conclusion, presently, the benefits of using DPP4 inhibitors or GLP1 receptor agonists for treatment of type 2 diabetes outweigh the risks. Nonetheless, their safety profile should be monitored and their indications should be widened cautiously. At present they remain contra-indicated in patients with a personal or family history of MTC or multiple endocrine neoplasia type 2.
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Affiliation(s)
- Roman Vangoitsenhoven
- Laboratory of Experimental Medicine and Endocrinology, Catholic University of Leuven, Leuven, Belgium
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45
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Cho YM, Merchant CE, Kieffer TJ. Targeting the glucagon receptor family for diabetes and obesity therapy. Pharmacol Ther 2012; 135:247-78. [DOI: 10.1016/j.pharmthera.2012.05.009] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 12/11/2022]
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Damdindorj B, Dezaki K, Kurashina T, Sone H, Rita R, Kakei M, Yada T. Exogenous and endogenous ghrelin counteracts GLP-1 action to stimulate cAMP signaling and insulin secretion in islet β-cells. FEBS Lett 2012; 586:2555-62. [PMID: 22750144 DOI: 10.1016/j.febslet.2012.06.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 06/20/2012] [Accepted: 06/21/2012] [Indexed: 10/28/2022]
Abstract
We studied interactive effects of insulinotropic GLP-1 and insulinostatic ghrelin on rat pancreatic islets. GLP-1 potentiated glucose-induced insulin release and cAMP production in isolated islets and [Ca(2+)](i) increases in single β-cells, and these potentiations were attenuated by ghrelin. Ghrelin suppressed [Ca(2+)](i) responses to an adenylate cyclase activator forskolin. Moreover, GLP-1-induced insulin release and cAMP production were markedly enhanced by [D-lys(3)]-GHRP-6, a ghrelin receptor antagonist, in isolated islets. These results indicate that both exogenous and endogenous islet-derived ghrelin counteracts glucose-dependent GLP-1 action to increase cAMP production, [Ca(2+)](i) and insulin release in islet β-cells, positioning ghrelin as a modulator of insulinotropic GLP-1.
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Affiliation(s)
- Boldbaatar Damdindorj
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan
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Basford CL, Prentice KJ, Hardy AB, Sarangi F, Micallef SJ, Li X, Guo Q, Elefanty AG, Stanley EG, Keller G, Allister EM, Nostro MC, Wheeler MB. The functional and molecular characterisation of human embryonic stem cell-derived insulin-positive cells compared with adult pancreatic beta cells. Diabetologia 2012; 55:358-71. [PMID: 22075915 DOI: 10.1007/s00125-011-2335-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 09/05/2011] [Indexed: 12/26/2022]
Abstract
AIMS/HYPOTHESIS Using a novel directed differentiation protocol, we recently generated up to 25% insulin-producing cells from human embryonic stem cells (hESCs) (insulin(+) cells). At this juncture, it was important to functionally and molecularly characterise these hESC-derived insulin(+) cells and identify key differences and similarities between them and primary beta cells. METHODS We used a new reporter hESC line with green fluorescent protein (GFP) cDNA targeted to the INS locus by homologous recombination (INS (GFP/w)) and an untargeted hESC line (HES2). INS (GFP/w) allowed efficient identification and purification of GFP-producing (INS:GFP(+)) cells. Insulin(+) cells were examined for key features of adult beta cells using microarray, quantitative PCR, secretion assays, imaging and electrophysiology. RESULTS Immunofluorescent staining showed complete co-localisation of insulin with GFP; however, cells were often multihormonal, many with granules containing insulin and glucagon. Electrophysiological recordings revealed variable K(ATP) and voltage-gated Ca(2+) channel activity, and reduced glucose-induced cytosolic Ca(2+) uptake. This translated into defective glucose-stimulated insulin secretion but, intriguingly, appropriate glucagon responses. Gene profiling revealed differences in global gene expression between INS:GFP(+) cells and adult human islets; however, INS:GFP(+) cells had remarkably similar expression of endocrine-lineage transcription factors and genes involved in glucose sensing and exocytosis. CONCLUSIONS/INTERPRETATION INS:GFP(+) cells can be purified from differentiated hESCs, providing a superior source of insulin-producing cells. Genomic analyses revealed that INS:GFP(+) cells collectively resemble immature endocrine cells. However, insulin(+) cells were heterogeneous, a fact that translated into important functional differences within this population. The information gained from this study may now be used to generate new iterations of functioning beta cells that can be purified for transplant.
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Affiliation(s)
- C L Basford
- Division of Cellular and Molecular Biology, Toronto General Research Institute, TMDT, Toronto, ON, Canada
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Park JH, Kim SJ, Park SH, Son DG, Bae JH, Kim HK, Han J, Song DK. Glucagon-like peptide-1 enhances glucokinase activity in pancreatic β-cells through the association of Epac2 with Rim2 and Rab3A. Endocrinology 2012; 153:574-82. [PMID: 22147008 DOI: 10.1210/en.2011-0259] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Glucokinase (GK), which phosphorylates D-glucose, is a major glucose sensor in β-cells for glucose-stimulated insulin secretion (GSIS) and is a promising new drug target for type 2 diabetes (T2D). In T2D, pancreatic β-cells exhibit defective glucose sensitivity, which leads to impaired GSIS. Although glucagon-like peptide-1-(7-36)-amide (GLP-1) is known to enhance β-cell glucose sensitivity, the effect of GLP-1 on GK activity is still unknown. The present study demonstrated that GLP-1 pretreatment for 30 min significantly enhanced GK activity in a glucose-dependent manner, with a lower Michaelis-Menten constant (K(m)) but unchanged maximal velocity (V(max)). Thus, GLP-1 acutely enhanced cellular glucose uptake, mitochondrial membrane potential, and cellular ATP levels in response to glucose in rat INS-1 and native β-cells. This effect of GLP-1 occurred via its G protein-coupled receptor pathway in a cAMP-dependent but protein kinase A-independent manner with evidence of exchange protein activated by cAMP (Epac) involvement. Silencing Epac2, interacting molecule of the small G protein Rab3 (Rim2), or Ras-associated protein Rab3A (Rab3A) significantly blocked the effect of GLP-1. These results suggested that GLP-1 can further potentiate GSIS by enhancing GK activity through the signaling of Epac2 to Rim2 and Rab3A, which is the similar pathway for GLP-1 to potentiate Ca(2+)-dependent insulin granule exocytosis. The present finding may also be an important mechanism of GLP-1 for recovery of GSIS in T2D.
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Affiliation(s)
- Jae-Hyung Park
- Department of Physiology, Keimyung University School of Medicine, Daegu 704-701, Korea
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49
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Bastien-Dionne PO, Valenti L, Kon N, Gu W, Buteau J. Glucagon-like peptide 1 inhibits the sirtuin deacetylase SirT1 to stimulate pancreatic β-cell mass expansion. Diabetes 2011; 60:3217-22. [PMID: 22013015 PMCID: PMC3219950 DOI: 10.2337/db11-0101] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The glucoincretin hormone glucagon-like peptide 1 (GLP-1) enhances glucose-stimulated insulin secretion and stimulates pancreatic β-cell mass expansion. We have previously shown that the forkhead transcription factor FoxO1 is a prominent transcriptional effector of GLP-1 signaling in the β-cell. FoxO1 activity is subject to a complex regulation by Akt-dependent phosphorylation and SirT1-mediated deacetylation. In this study, we aimed at investigating the potential role of SirT1 in GLP-1 action. RESEARCH DESIGN AND METHODS FoxO1 acetylation levels and binding to SirT1 were studied by Western immunoblot analysis in INS832/13 cells. SirT1 activity was evaluated using an in vitro deacetylation assay and correlated with the NAD(+)-to-NADH ratio. The implication of SirT1 in GLP-1-induced proliferation was investigated by BrdU incorporation assay. Furthermore, we determined β-cell replication and mass in wild-type and transgenic mice with SirT1 gain of function after daily administration of exendin-4 for 1 week. RESULTS Our data show that GLP-1 increases FoxO1 acetylation, decreases the binding of SirT1 to FoxO1, and stunts SirT1 activity in β-INS832/13 cells. GLP-1 decreases both the NAD(+)-to-NADH ratio and SirT1 expression in INS cells and isolated islets, thereby providing possible mechanisms by which GLP-1 could modulate SirT1 activity. Finally, the action of GLP-1 on β-cell mass expansion is abolished in both transgenic mice and cultured β-cells with increased dosage of SirT1. CONCLUSIONS Our study shows for the first time that the glucoincretin hormone GLP-1 modulates SirT1 activity and FoxO1 acetylation in β-cells. We also identify SirT1 as a negative regulator of β-cell proliferation.
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Affiliation(s)
- Pierre-Olivier Bastien-Dionne
- Department of Medicine, Université Laval and Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Quebec (CRIUCPQ), Quebec City, Quebec, Canada
| | - Luca Valenti
- Department of Internal Medicine, Universita' degli Studi di Milano and Ospedale Policlinico Fondazione Instituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Ning Kon
- Department of Pathology and Cell Biology, Institute for Cancer Genetics, Columbia University, New York, New York
| | - Wei Gu
- Department of Pathology and Cell Biology, Institute for Cancer Genetics, Columbia University, New York, New York
| | - Jean Buteau
- Department of Medicine, Université Laval and Centre de Recherche de l’Institut Universitaire de Cardiologie et de Pneumologie de Quebec (CRIUCPQ), Quebec City, Quebec, Canada
- Corresponding author: Jean Buteau,
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50
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MacDonald PE. Signal integration at the level of ion channel and exocytotic function in pancreatic β-cells. Am J Physiol Endocrinol Metab 2011; 301:E1065-9. [PMID: 21934040 DOI: 10.1152/ajpendo.00426.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Whole body energy balance is ensured by the exquisite control of insulin secretion, the dysregulation of which has serious consequences. Although a great deal has been learned about the control of insulin secretion from pancreatic β-cells in the past 30 years, there remains much to be understood about the molecular mechanisms and interactions that underlie the precise control of this process. Numerous molecular interactions at the plasma membrane mediate the excitatory and amplifying events involved in insulin secretion; this includes interactions between ion channels, signal transduction machinery, and exocytotic proteins. The present Perspectives article considers evidence that key membrane and membrane-associated proteins essential to insulin secretion are regulated in concert as a functional unit, ensuring an integrated excitatory and exocytotic response to the signals that control insulin secretion.
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Affiliation(s)
- Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada.
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