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Das S, Ravi H, Babu A, Banerjee M, Kanagavalli R, Dhanasekaran S, Devi Rajeswari V, Venkatraman G, Ramanathan G. Therapeutic potentials of glucose-dependent insulinotropic polypeptide (GIP) in T2DM: Past, present, and future. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 142:293-328. [PMID: 39059989 DOI: 10.1016/bs.apcsb.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Type 2 diabetes mellitus (T2DM) is a worldwide health problem that has raised major concerns to the public health community. This chronic condition typically results from the cell's inability to respond to normal insulin levels. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the primary incretin hormones secreted from the intestinal tract. While clinical research has extensively explored the therapeutic potential of GLP-1R in addressing various T2DM-related abnormalities, the possibility of GIPR playing an important role in T2DM treatment is still under investigation. Evidence suggests that GIP is involved in the pathophysiology of T2DM. This chapter focuses on examining the role of GIP as a therapeutic molecule in combating T2DM, comparing the past, present, and future scenarios. Our goal is to delve into how GIP may impact pancreatic β-cell function, adipose tissue uptake, and lipid metabolism. Furthermore, we will elucidate the mechanistic functions of GIP and its receptors in relation to other clinical conditions like cardiovascular diseases, non-alcoholic fatty liver diseases, neurodegenerative diseases, and renal disorders. Additionally, this chapter will shed light on the latest advancements in pharmacological management for T2DM, highlighting potential structural modifications of GIP and the repurposing of drugs, while also addressing the challenges involved in bringing GIP-based treatments into clinical practice.
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Affiliation(s)
- Soumik Das
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Harini Ravi
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Achsha Babu
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Manosi Banerjee
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - R Kanagavalli
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Sivaraman Dhanasekaran
- School of Energy Technology, Pandit Deendayal Energy University, Knowledge Corridor, Gandhinagar, Gujarat, India
| | - V Devi Rajeswari
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Ganesh Venkatraman
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Gnanasambandan Ramanathan
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India.
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2
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Ramasamy I. Physiological Appetite Regulation and Bariatric Surgery. J Clin Med 2024; 13:1347. [PMID: 38546831 PMCID: PMC10932430 DOI: 10.3390/jcm13051347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/22/2024] [Accepted: 02/24/2024] [Indexed: 04/10/2024] Open
Abstract
Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.
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Affiliation(s)
- Indra Ramasamy
- Department of Blood Sciences, Conquest Hospital, Hastings TN37 7RD, UK
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Pocai A. G protein-coupled receptors and obesity. Front Endocrinol (Lausanne) 2023; 14:1301017. [PMID: 38161982 PMCID: PMC10757641 DOI: 10.3389/fendo.2023.1301017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024] Open
Abstract
G protein-coupled receptors (GPCRs) have emerged as important drug targets for various chronic diseases, including obesity and diabetes. Obesity is a complex chronic disease that requires long term management predisposing to type 2 diabetes, heart disease, and some cancers. The therapeutic landscape for GPCR as targets of anti-obesity medications has undergone significant changes with the approval of semaglutide, the first peptide glucagon like peptide 1 receptor agonist (GLP-1RA) achieving double digit weight loss (≥10%) and cardiovascular benefits. The enhanced weight loss, with the expected beneficial effect on obesity-related complications and reduction of major adverse cardiovascular events (MACE), has propelled the commercial opportunity for the obesity market leading to new players entering the space. Significant progress has been made on approaches targeting GPCRs such as single peptides that simultaneously activate GIP and/or GCGR in addition to GLP1, oral tablet formulation of GLP-1, small molecules nonpeptidic oral GLP1R and fixed-dose combination as well as add-on therapy for patients already treated with a GLP-1 agonist.
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Affiliation(s)
- Alessandro Pocai
- Cardiovascular and Metabolic Disease, Johnson & Johnson Innovative Medicine Research & Development, Spring House, PA, United States
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4
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Folli F, Finzi G, Manfrini R, Galli A, Casiraghi F, Centofanti L, Berra C, Fiorina P, Davalli A, La Rosa S, Perego C, Higgins PB. Mechanisms of action of incretin receptor based dual- and tri-agonists in pancreatic islets. Am J Physiol Endocrinol Metab 2023; 325:E595-E609. [PMID: 37729025 PMCID: PMC10874655 DOI: 10.1152/ajpendo.00236.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/15/2023] [Accepted: 09/16/2023] [Indexed: 09/22/2023]
Abstract
Simultaneous activation of the incretin G-protein-coupled receptors (GPCRs) via unimolecular dual-receptor agonists (UDRA) has emerged as a new therapeutic approach for type 2 diabetes. Recent studies also advocate triple agonism with molecules also capable of binding the glucagon receptor. In this scoping review, we discuss the cellular mechanisms of action (MOA) underlying the actions of these novel and therapeutically important classes of peptide receptor agonists. Clinical efficacy studies of several UDRAs have demonstrated favorable results both as monotherapies and when combined with approved hypoglycemics. Although the additive insulinotropic effects of dual glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic peptide receptor (GIPR) agonism were anticipated based on the known actions of either glucagon-like peptide-1 (GLP-1) or glucose-dependent insulinotropic peptide (GIP) alone, the additional benefits from GCGR were largely unexpected. Whether additional synergistic or antagonistic interactions among these G-protein receptor signaling pathways arise from simultaneous stimulation is not known. The signaling pathways affected by dual- and tri-agonism require more trenchant investigation before a comprehensive understanding of the cellular MOA. This knowledge will be essential for understanding the chronic efficacy and safety of these treatments.
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Affiliation(s)
- Franco Folli
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
- Unit of Diabetes, Endocrinology and Metabolism, San Paolo Hospital, ASST Santi Paolo e Carlo, Milan, Italy
| | - Giovanna Finzi
- Unit of Pathology, Department of Oncology, ASST Sette Laghi, Varese, Italy
| | - Roberto Manfrini
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
- Unit of Diabetes, Endocrinology and Metabolism, San Paolo Hospital, ASST Santi Paolo e Carlo, Milan, Italy
| | - Alessandra Galli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Francesca Casiraghi
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Lucia Centofanti
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Cesare Berra
- IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Paolo Fiorina
- International Center for T1D, Pediatric Clinical Research Center Romeo ed Enrica Invernizzi, DIBIC, Università di Milano, Milan, Italy
- Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
- Division of Endocrinology, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Alberto Davalli
- Diabetes and Endocrinology Unit, Department of Internal Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Stefano La Rosa
- Unit of Pathology, Department of Medicine and Technological Innovation, University of Insubria, Varese, Italy
| | - Carla Perego
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Paul B Higgins
- Department of Life & Physical Sciences, Atlantic Technological University, Letterkenny, Ireland
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5
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Cataldi S, Aprile M, Perfetto C, Angot B, Cormont M, Ciccodicola A, Tanti JF, Costa V. GIPR expression is induced by thiazolidinediones in a PPARγ-independent manner and repressed by obesogenic stimuli. Eur J Cell Biol 2023; 102:151320. [PMID: 37130450 DOI: 10.1016/j.ejcb.2023.151320] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 05/04/2023] Open
Abstract
Adipose tissue (AT) dysfunctions are associated with the onset of insulin resistance (IR) and type 2 diabetes mellitus (T2DM). Targeting glucose-dependent insulinotropic peptide receptor (GIPR) is a valid option to increase the efficacy of glucagon-like peptide 1 (GLP-1) receptor agonists in T2DM treatment. Nevertheless, the therapeutic potential of targeting the GIP/GIPR axis and its effect on the AT are controversial. In this work, we explored the expression and regulation of GIPR in precursor cells and mature adipocytes, investigating if and how obesogenic stimuli and thiazolidinediones perturb GIPR expression. Using publicly available gene expression datasets, we assessed that, among white adipose tissue (WAT) cells, adipocytes express lower levels of GIPR compared to cells of mesothelial origin, pericytes, dendritic and NK/T cells. However, we report that GIPR levels markedly increase during the in vitro differentiation of both murine and human adipocytes, from 3T3-L1 and human mesenchymal precursor cells (MSCs), respectively. Notably, we demonstrated that thiazolidinediones - ie. synthetic PPARγ agonists widely used as anti-diabetic drugs and contained in the adipogenic mix - markedly induce GIPR expression. Moreover, using multiple in vitro systems, we assessed that thiazolidinediones induce GIPR in a PPARγ-independent manner. Our results support the hypothesis that PPARγ synthetic agonists may be used to increase GIPR levels in AT, potentially affecting in turn the targeting of GIP system in patients with metabolic dysfunctions. Furthermore, we demonstrate in vitro and in vivo that proinflammatory stimuli, and especially the TNFα, represses GIPR both in human and murine adipocytes, even though discordant results were obtained between human and murine cellular systems for other cytokines. Finally, we demonstrated that GIPR is negatively affected also by the excessive lipid engulfment. Overall, we report that obesogenic stimuli - ie. pro-inflammatory cytokines and the increased lipid accumulation - and PPARγ synthetic ligands oppositely modulate GIPR expression, possibly influencing the effectiveness of GIP agonists.
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Affiliation(s)
- Simona Cataldi
- Institute of Genetics and Biophysics ''Adriano Buzzati-Traverso'', CNR, Via P. Castellino 111, 80131 Naples, Italy
| | - Marianna Aprile
- Institute of Genetics and Biophysics ''Adriano Buzzati-Traverso'', CNR, Via P. Castellino 111, 80131 Naples, Italy
| | - Caterina Perfetto
- Institute of Genetics and Biophysics ''Adriano Buzzati-Traverso'', CNR, Via P. Castellino 111, 80131 Naples, Italy
| | - Brice Angot
- Université Côte d'Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France
| | - Mireille Cormont
- Université Côte d'Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France
| | - Alfredo Ciccodicola
- Institute of Genetics and Biophysics ''Adriano Buzzati-Traverso'', CNR, Via P. Castellino 111, 80131 Naples, Italy; Department of Science and Technology, University of Naples ''Parthenope'', Naples, Italy
| | - Jean-Francois Tanti
- Université Côte d'Azur, Inserm UMR1065, C3M, Team Cellular and Molecular Pathophysiology of Obesity, 06204 Nice, France.
| | - Valerio Costa
- Institute of Genetics and Biophysics ''Adriano Buzzati-Traverso'', CNR, Via P. Castellino 111, 80131 Naples, Italy; NBFC, National Biodiversity Future Center, Palermo 90133, Italy.
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6
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Bulushova NV, Zalunin IA, Asrarkulova AS, Kozlov DG. Incretin Analogues in the Therapy of Type 2 Diabetes and Obesity. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822070031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Yang G, Liang X, Jiang Y, Li C, Zhang Y, Zhang X, Chang X, Shen Y, Meng X. Molecular Characterization of Grass Carp GIPR and Effect of Nutrition States, Insulin, and Glucagon on Its Expression. AQUACULTURE NUTRITION 2022; 2022:4330251. [PMID: 36860432 PMCID: PMC9973162 DOI: 10.1155/2022/4330251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 10/08/2022] [Accepted: 10/25/2022] [Indexed: 06/18/2023]
Abstract
GIP plays an important regulatory role in glucose and lipid metabolism. As the specific receptor, GIPR is involved in this physiological process. To assess the roles of GIPR in teleost, the GIPR gene was cloned from grass carp. The ORF of cloned GIPR gene was 1560 bp, encoding 519 amino acids. The grass carp GIPR was the G-protein-coupled receptor which contains seven predicted transmembrane domains. In addition, two predicted glycosylation sites were contained in the grass carp GIPR. The grass carp GIPR expression is in multiple tissues and is highly expressed in the kidney, brain regions, and visceral fat tissue. In the OGTT experiment, the GIPR expression is markedly decreased in the kidney, visceral fat, and brain by treatment with glucose for 1 and 3 h. In the fast and refeeding experiment, the GIPR expression in the kidney and visceral fat tissue was significantly induced in the fast groups. In addition, the GIPR expression levels were markedly decreased in the refeeding groups. In the present study, the visceral fat accumulation of grass carp was induced by overfed. The GIPR expression was significantly decreased in the brain, kidney, and visceral fat tissue of overfed grass carp. In primary hepatocytes, the GIPR expression was promoted by treatment with oleic acid and insulin. The GIPR mRNA levels were significantly reduced by treatment with glucose and glucagon in the grass carp primary hepatocytes. To our knowledge, this is the first time the biological role of GIPR is unveiled in teleost.
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Affiliation(s)
- Guokun Yang
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
- Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, China
| | - Xiaomin Liang
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
| | - Yanle Jiang
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
| | - Chengquan Li
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
| | - Yanmin Zhang
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
- Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, China
| | - Xindang Zhang
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
- Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, China
| | - Xulu Chang
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
- Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, China
| | - Yawei Shen
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
- Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, China
| | - Xiaolin Meng
- College of Fisheries, Henan Normal University, Xinxiang 453007, China
- Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, China
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8
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Campbell JE, Beaudry JL, Svendsen B, Baggio LL, Gordon AN, Ussher JR, Wong CK, Gribble FM, D’Alessio DA, Reimann F, Drucker DJ. GIPR Is Predominantly Localized to Nonadipocyte Cell Types Within White Adipose Tissue. Diabetes 2022; 71:1115-1127. [PMID: 35192688 PMCID: PMC7612781 DOI: 10.2337/db21-1166] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/16/2022] [Indexed: 02/02/2023]
Abstract
The incretin hormone glucose-dependent insulinotropic polypeptide (GIP) augments glucose-dependent insulin secretion through its receptor expressed on islet β-cells. GIP also acts on adipose tissue; yet paradoxically, both enhanced and reduced GIP receptor (GIPR) signaling reduce adipose tissue mass and attenuate weight gain in response to nutrient excess. Moreover, the precise cellular localization of GIPR expression within white adipose tissue (WAT) remains uncertain. We used mouse genetics to target Gipr expression within adipocytes. Surprisingly, targeting Cre expression to adipocytes using the adiponectin (Adipoq) promoter did not produce meaningful reduction of WAT Gipr expression in Adipoq-Cre:Giprflx/flx mice. In contrast, adenoviral expression of Cre under the control of the cytomegalovirus promoter, or transgenic expression of Cre using nonadipocyte-selective promoters (Ap2/Fabp4 and Ubc) markedly attenuated WAT Gipr expression. Analysis of single-nucleus RNA-sequencing, adipose tissue data sets localized Gipr/GIPR expression predominantly to pericytes and mesothelial cells rather than to adipocytes. Together, these observations reveal that adipocytes are not the major GIPR+ cell type within WAT-findings with mechanistic implications for understanding how GIP and GIP-based co-agonists control adipose tissue biology.
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Affiliation(s)
- Jonathan E. Campbell
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Department of Medicine, Division of Endocrinology, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
- Corresponding authors: Jonathan E. Campbell, , or Daniel J. Drucker,
| | - Jacqueline L. Beaudry
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Berit Svendsen
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Laurie L. Baggio
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Andrew N. Gordon
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - John R. Ussher
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Chi Kin Wong
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
| | - Fiona M. Gribble
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, U.K
| | - David A. D’Alessio
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Department of Medicine, Division of Endocrinology, Duke University, Durham, NC
| | - Frank Reimann
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, U.K
| | - Daniel J. Drucker
- Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Corresponding authors: Jonathan E. Campbell, , or Daniel J. Drucker,
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9
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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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10
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Yuliantie E, van der Velden WJC, Labroska V, Dai A, Zhao F, Darbalaei S, Deganutti G, Xu T, Zhou Q, Yang D, Rosenkilde MM, Sexton PM, Wang MW, Wootten D. Insights into agonist-elicited activation of the human glucose-dependent insulinotropic polypeptide receptor. Biochem Pharmacol 2021; 192:114715. [PMID: 34339714 DOI: 10.1016/j.bcp.2021.114715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 01/30/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and its receptor (GIPR) are part of the incretin system that regulates glucose homeostasis. A series of GIPR residues putatively important for ligand binding and receptor activation were mutated and pharmacologically evaluated using GIPR selective agonists in cAMP accumulation, ERK1/2 phosphorylation (pERK1/2) and β-arrestin 2 recruitment assays. The impact of mutation on ligand efficacy was determined by operational modelling of experimental data for each mutant, with results mapped onto the full-length, active-state GIPR structure. Two interaction networks, comprising transmembrane helix (TM) 7, TM1 and TM2, and extracellular loop (ECL) 2, TM5 and ECL3 were revealed, respectively. Both networks were critical for Gαs-mediated cAMP accumulation and the recruitment of β-arrestin 2, however, cAMP response was more sensitive to alanine substitution, with most mutated residues displaying reduced signaling. Unlike the other two assays, activation of ERK1/2 was largely independent of the network involving ECL2, TM5 and ECL3, indicating that pERK1/2 is at least partially distinct from Gαs or β-arrestin pathways and this network is also crucial for potential biased agonism at GIPR. Collectively, our work advances understanding of the structure-function relationship of GIPR and provides a framework for the design and/or interpretation of GIP analogues with unique signaling profiles.
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Affiliation(s)
- Elita Yuliantie
- The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | | | - Viktorija Labroska
- The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Antao Dai
- The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Fenghui Zhao
- School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Sanaz Darbalaei
- The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Giuseppe Deganutti
- Centre for Sport, Exercise and Life Sciences, Faculty of Health and Life Sciences, Alison Gingell Building, Coventry University, Coventry, CV1 2DS, UK
| | - Tongyang Xu
- School of Pharmacy, Fudan University, Shanghai 201203, China
| | - Qingtong Zhou
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Dehua Yang
- The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen N DK-2200, Denmark.
| | - Patrick M Sexton
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia; ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
| | - Ming-Wei Wang
- The National Center for Drug Screening and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Pharmacy, Fudan University, Shanghai 201203, China; Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.
| | - Denise Wootten
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia; ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
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11
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Chen X, He X, Guo Y, Liu L, Li H, Tan J, Feng W, Guan H, Cao X, Xiao H, Li Y. Glucose-dependent insulinotropic polypeptide modifies adipose plasticity and promotes beige adipogenesis of human omental adipose-derived stem cells. FASEB J 2021; 35:e21534. [PMID: 33817830 DOI: 10.1096/fj.201903253r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/05/2021] [Accepted: 03/01/2021] [Indexed: 02/06/2023]
Abstract
The adipocyte precursors (APs) located in white adipose tissue (WAT) are functionally significant in adipose plasticity and browning. Modifying adipogenesis or WAT browning targeted on APs is a promising mechanism for anti-obesity drug. We herein explored the in vitro actions and mechanisms of glucose-dependent insulinotropic polypeptide (GIP), a gut-derived peptide, in human adipose-derived mesenchymal stem cells (hADSCs) isolated from omentum. The hADSCs were cotreated with 100 nM GIP with or without equimolar concentration of GIP3-42 (a GIP receptor antagonist), and subsequently examined in vitro. CCK-8, EdU incorporation, and flow cytometry assays were used to assess cellular proliferation. Annexin V FTIC/PI double stain, TUNEL staining, and Western blot were applied for apoptosis evaluation. Adipogenesis was reflected by Western blot, real-time PCR, Oil Red O staining, mitochondrial staining, and mitochondrial DNA analysis. Results showed that GIP promoted proliferation and inhibited apoptosis of hADSCs via pleiotropic effects. Besides, GIP facilitated de novo beige adipogenesis, by accelerating mitotic clonal expansion (MCE), upregulating core adipogenic regulators (C/EBPα and PPARγ), augmenting beige-related genes (UCP1, PGC1α, and PRDM16), increasing mitochondrial content and improving beige adipocyte functionalities. Above all, our study expands knowledge on the mechanisms of GIP modifying adipogenesis especially in inducing beige adipogenesis, and thus provides a theoretical support for clinical usage of GIP on obesity treatment.
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Affiliation(s)
- Xueying Chen
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiaoying He
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yan Guo
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Liehua Liu
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Hai Li
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jinfu Tan
- Center for Gastrointestinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Weidong Feng
- Center for Gastrointestinal Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Hongyu Guan
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiaopei Cao
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Haipeng Xiao
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yanbing Li
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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12
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Sabiha B, Bhatti A, Roomi S, John P, Ali J. In silico analysis of non-synonymous missense SNPs (nsSNPs) in CPE, GNAS genes and experimental validation in type II diabetes mellitus through Next Generation Sequencing. Genomics 2021; 113:2426-2440. [PMID: 34029697 DOI: 10.1016/j.ygeno.2021.05.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 12/11/2020] [Accepted: 05/19/2021] [Indexed: 12/12/2022]
Abstract
Non-synonymous missense SNPs (nsSNPs) in CPE and GNAS genes were investigated computationally. In silico identified nsSNPs were experimentally validated in type II diabetes mellitus (T2DM) in Pakistani Pathan population using next generation sequencing (NGS). Sixty two high-risk nsSNPs in CPE and 44 in GNAS were identified. Only 12 in GNAS were clinically significant. Thirty six high-risk nsSNPs in CPE and 08 clinically significant nsSNPs in GNAS lies in the most conserved regions. I-mutant predicted that nsSNPs decrease the proteins stability and ModPred predicted 20 and 12 post-translational modification sites in CPE and GNAS proteins respectively. Ramachandran plot showed 88.7% residues are in the most favored region of protein models. By experimentation, none of the nsSNPs were found to be associated with T2DM. In conclusion, this study differentiates the deleterious nsSNPs from the neutral ones. Although nsSNPs are not associated with T2DM, they can be targeted in other CPE and GNAS genes related disorders.
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Affiliation(s)
- Bibi Sabiha
- Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan
| | - Attya Bhatti
- Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan.
| | - Sohaib Roomi
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Peter John
- Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad, Pakistan
| | - Johar Ali
- Center for Genome Sciences, Rehman Medical College, Phase-V, Hayatabad, Peshawar, Khyber Pakhtunkhwa, Pakistan
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13
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Oduori OS, Murao N, Shimomura K, Takahashi H, Zhang Q, Dou H, Sakai S, Minami K, Chanclon B, Guida C, Kothegala L, Tolö J, Maejima Y, Yokoi N, Minami Y, Miki T, Rorsman P, Seino S. Gs/Gq signaling switch in β cells defines incretin effectiveness in diabetes. J Clin Invest 2021; 130:6639-6655. [PMID: 33196462 DOI: 10.1172/jci140046] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
By restoring glucose-regulated insulin secretion, glucagon-like peptide-1-based (GLP-1-based) therapies are becoming increasingly important in diabetes care. Normally, the incretins GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) jointly maintain normal blood glucose levels by stimulation of insulin secretion in pancreatic β cells. However, the reason why only GLP-1-based drugs are effective in improving insulin secretion after presentation of diabetes has not been resolved. ATP-sensitive K+ (KATP) channels play a crucial role in coupling the systemic metabolic status to β cell electrical activity for insulin secretion. Here, we have shown that persistent membrane depolarization of β cells due to genetic (β cell-specific Kcnj11-/- mice) or pharmacological (long-term exposure to sulfonylureas) inhibition of the KATP channel led to a switch from Gs to Gq in a major amplifying pathway of insulin secretion. The switch determined the relative insulinotropic effectiveness of GLP-1 and GIP, as GLP-1 can activate both Gq and Gs, while GIP only activates Gs. The findings were corroborated in other models of persistent depolarization: a spontaneous diabetic KK-Ay mouse and nondiabetic human and mouse β cells of pancreatic islets chronically treated with high glucose. Thus, a Gs/Gq signaling switch in β cells exposed to chronic hyperglycemia underlies the differential insulinotropic potential of incretins in diabetes.
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Affiliation(s)
- Okechi S Oduori
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Murao
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Haiqiang Dou
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Shihomi Sakai
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohtaro Minami
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Belen Chanclon
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lakshmi Kothegala
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Johan Tolö
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.,Laboratory of Animal Breeding and Genetics, Division of Applied Biosciences, Kyoto University Graduate School of Agriculture, Kyoto, Japan
| | - Yasuhiro Minami
- Division of Cell Physiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takashi Miki
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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14
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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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15
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MicroRNA-203a regulates pancreatic β cell proliferation and apoptosis by targeting IRS2. Mol Biol Rep 2020; 47:7557-7566. [PMID: 32929654 DOI: 10.1007/s11033-020-05818-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 09/04/2020] [Indexed: 12/16/2022]
Abstract
The main pathogenesis of type 1 diabetes mellitus (T1DM) is autoimmune-mediated apoptosis of pancreatic islet β cells. We sought to characterize the function of microRNA-203a (miR-203a) on pancreatic islet β cell proliferation and apoptosis. In situ hybridization was used to detect the expression of miR-203a in islet β cells in normal and hyperglycaemic non-obese diabetic (NOD) mice. Cell proliferation was measured by cell counting kit eight and cell apoptosis was detected using flow cytometry. Insulin receptor substrate 2 (IRS2/Irs2) was determined to be a direct target of miR-203a by Luciferase reporter assay. We detected the effects of miR-203a overexpression or inhibition on proliferation and apoptosis of IRS2-overexpressing or IRS2-knockdown MIN6 cells respectively, and preliminarily explored the downstream targets of the IRS2 pathway. NOD mice model was used to detect miR-203a inhibitor treatment for diabetes. Our experiment showed miR-203a was upregulated in pancreatic β cells of hyperglycaemic NOD mice. Elevated miR-203a expression inhibited the proliferation and promoted the apoptosis of MIN6 cells. IRS2/Irs2 is a novel target gene directly regulated by miR-203a and miR-203a overexpression downregulated the expression of IRS2. Irs2 silencing reduced cell proliferation and increased apoptosis. Irs2 overexpression could abolish the pro-apoptotic and anti-proliferative effects of miR-203a on MIN6 cells. Hyperglycemia in newly hyperglycemic NOD mice was under control after treatment with miR-203a inhibitor. Our study suggests that miR-203a regulates pancreatic β cell proliferation and apoptosis by targeting IRS2, treatment with miR-203a inhibitors and IRS2 might provide a new therapeutic strategy for T1DM.
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16
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Glucose signaling in the brain and periphery to memory. Neurosci Biobehav Rev 2020; 110:100-113. [DOI: 10.1016/j.neubiorev.2019.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 01/30/2019] [Accepted: 03/24/2019] [Indexed: 02/08/2023]
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Heimbürger SM, Bergmann NC, Augustin R, Gasbjerg LS, Christensen MB, Knop FK. Glucose-dependent insulinotropic polypeptide (GIP) and cardiovascular disease. Peptides 2020; 125:170174. [PMID: 31689454 DOI: 10.1016/j.peptides.2019.170174] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 12/20/2022]
Abstract
Accumulating evidence suggests that glucose-dependent insulinotropic polypeptide (GIP) in addition to its involvement in type 2 diabetic pathophysiology may be involved in the development of obesity and the pathogenesis of cardiovascular disease. In this review, we outline recent preclinical and clinical cardiovascular-related discoveries about GIP. These include chronotropic and blood pressure-lowering effects of GIP. Furthermore, GIP has been suggested to control vasodilation via secretion of nitric oxide, and vascular leukocyte adhesion and inflammation via expression and secretion of endothelin 1. Also, GIP seems to regulate circulating lipids via effects on adipose tissue uptake and metabolism of lipids. Lastly, we discuss how dysmetabolic conditions such as obesity and type 2 diabetes may shift the actions of GIP in an atherogenic direction, and we provide a perspective on the therapeutic potential of GIP receptor agonism and antagonism in cardiovascular diseases. We conclude that GIP actions may have implications for the development of cardiovascular disease, but also that the potential of GIP-based drugs for the treatment of cardiovascular disease currently is uncertain.
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Affiliation(s)
- Sebastian M Heimbürger
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Steno Diabetes Center Copenhagen, Gentofte, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Natasha C Bergmann
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Robert Augustin
- Department of Cardiometabolic Diseases Research, Boehringer Ingelheim GmbH & CoKG, Biberach, Germany
| | - Lærke S Gasbjerg
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel B Christensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Steno Diabetes Center Copenhagen, Gentofte, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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18
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Gabe MBN, van der Velden WJC, Smit FX, Gasbjerg LS, Rosenkilde MM. Molecular interactions of full-length and truncated GIP peptides with the GIP receptor - A comprehensive review. Peptides 2020; 125:170224. [PMID: 31809770 DOI: 10.1016/j.peptides.2019.170224] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/17/2022]
Abstract
Enzymatic cleavage of endogenous peptides is a commonly used principle to initiate, modulate and terminate action for instance among cytokines and peptide hormones. The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), and the related hormone glucagon-like peptide-2 (GLP-2) are all rapidly N-terminally truncated with severe loss of intrinsic activity. The most abundant circulating form of full length GIP(1-42) is GIP(3-42) (a dipeptidyl peptidase-4 (DPP-4) product). GIP(1-30)NH2 is another active form resulting from prohormone convertase 2 (PC2) cleavage of proGIP. Like GIP(1-42), GIP(1-30)NH2 is a substrate for DPP-4 generating GIP(3-30)NH2 which, compared to GIP(3-42), binds with higher affinity and very efficiently inhibits GIP receptor (GIPR) activity with no intrinsic activity. Here, we review the action of these four and multiple other N- and C-terminally truncated forms of GIP with an emphasis on molecular pharmacology, i.e. ligand binding, subsequent receptor activation and desensitization. Our overall conclusion is that the N-terminus is essential for receptor activation as GIP N-terminal truncation leads to decreased/lost intrinsic activity and antagonism (similar to GLP-1 and GLP-2), whereas the C-terminal extension of GIP(1-42), as compared to GLP-1, GLP-2 and glucagon (29-33 amino acids), has no apparent impact on the GIPR in vitro, but may play a role for other properties such as stability and tissue distribution. A deeper understanding of the molecular interaction of naturally occurring and designed GIP-based peptides, and their impact in vivo, may contribute to a future therapeutic targeting of the GIP system - either with agonists or with antagonists, or both.
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Affiliation(s)
- Maria Buur Nordskov Gabe
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Wijnand J C van der Velden
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Florent Xavier Smit
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Lærke Smidt Gasbjerg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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19
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Shah FA, Mahmud H, Gallego-Martin T, Jurczak MJ, O’Donnell CP, McVerry BJ. Therapeutic Effects of Endogenous Incretin Hormones and Exogenous Incretin-Based Medications in Sepsis. J Clin Endocrinol Metab 2019; 104:5274-5284. [PMID: 31216011 PMCID: PMC6763279 DOI: 10.1210/jc.2019-00296] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 06/13/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Sepsis, a complex disorder characterized by a dysregulated immune response to an inciting infection, affects over one million Americans annually. Dysglycemia during sepsis hospitalization confers increased risk of organ dysfunction and death, and novel targets for the treatment of sepsis and maintenance of glucose homeostasis are needed. Incretin hormones are secreted by enteroendocrine cells in response to enteral nutrients and potentiate insulin release from pancreatic β cells in a glucose-dependent manner, thereby reducing the risk of insulin-induced hypoglycemia. Incretin hormones also reduce systemic inflammation in preclinical studies, but studies of incretins in the setting of sepsis are limited. METHODS In this bench-to-bedside mini-review, we detail the evidence to support incretin hormones as a therapeutic target in patients with sepsis. We performed a PubMed search using the medical subject headings "incretins," "glucagon-like peptide-1," "gastric inhibitory peptide," "inflammation," and "sepsis." RESULTS Incretin-based therapies decrease immune cell activation, inhibit proinflammatory cytokine release, and reduce organ dysfunction and mortality in preclinical models of sepsis. Several small clinical trials in critically ill patients have suggested potential benefit in glycemic control using exogenous incretin infusions, but these studies had limited power and were performed in mixed populations. Further clinical studies examining incretins specifically in septic populations are needed. CONCLUSIONS Targeting the incretin hormone axis in sepsis may provide a means of not only promoting euglycemia in sepsis but also attenuating the proinflammatory response and improving clinical outcomes.
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Affiliation(s)
- Faraaz Ali Shah
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Veteran Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
- Correspondence and Reprint Requests: Faraaz Ali Shah, MD, MPH, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh Medical Center, 3459 Fifth Avenue NW, 628 MUH, Pittsburgh, Pennsylvania 15213. E-mail:
| | - Hussain Mahmud
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Teresa Gallego-Martin
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Michael J Jurczak
- Division of Endocrinology and Metabolism, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Christopher P O’Donnell
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Bryan J McVerry
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
- Center for Medicine and the Microbiome, University of Pittsburgh, Pittsburgh, Pennsylvania
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20
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Ježek P, Jabůrek M, Plecitá-Hlavatá L. Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes. Antioxid Redox Signal 2019; 31:722-751. [PMID: 30450940 PMCID: PMC6708273 DOI: 10.1089/ars.2018.7656] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022]
Abstract
Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.
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Affiliation(s)
- Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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21
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Sakane N, Osaki N, Takase H, Suzuki J, Suzukamo C, Nirengi S, Suganuma A, Shimotoyodome A. The study of metabolic improvement by nutritional intervention controlling endogenous GIP (Mini Egg study): a randomized, cross-over study. Nutr J 2019; 18:52. [PMID: 31477157 PMCID: PMC6720405 DOI: 10.1186/s12937-019-0472-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/13/2019] [Indexed: 02/07/2023] Open
Abstract
Background Given the major role of glucose-dependent insulinotropic polypeptide (GIP) in the regulation of adiposity, this study examined the effects induced by a diet based on the Japanese tradition (SMART WASHOKU) on the visceral fat area (VFA) and GIP secretions. Methods Overweight/obese men (n = 21; mean age, 41.0 ± 9.0 years; mean BMI, 25.2 ± 2.0 kg/m2) without diabetes were placed on either a SMART WASHOKU or control meal for 2 weeks, in a randomized, cross-over setup with a four-week washout period. Results For the meal tolerance test, blood samples were collected at 0, 30, 60, 120, 180, and 240 min post-meal, followed by measuring blood glucose, insulin, GIP, and glucagon-like peptide-1 (GLP-1) levels. Relative to a control meal, SMART WASHOKU meal yielded significantly lower plasma postprandial GIP concentrations (AUC: 700.0 ± 208.0 vs. 1117.0 ± 351.4 pmol/L・4 h, P < 0.05); however, between meals, there was no significant difference in the levels of GLP-1, peptide YY, and ghrelin. Compared to the control meal, SMART WASHOKU intervention significantly reduced VFA and the levels of LDL-cholesterol, triglyceride, and HbA1c after the chronic meal intervention. Conclusions In conclusion, a SMART WASHOKU meal may decrease VFA and improve metabolic parameters in overweight/obese men, possibly via suppressing GIP secretion.
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Affiliation(s)
- Naoki Sakane
- Division of Preventive Medicine, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, 1-1 Mukaihata-cho, Fukakusa, Fushimi-ku, Kyoto, 612-8555, Japan.
| | - Noriko Osaki
- Biological ScienceResearch, Kao Corporation, 2-1-3 Bunka, Sumida, Tokyo, 131-8501, Japan
| | - Hideto Takase
- Biological ScienceResearch, Kao Corporation, 2-1-3 Bunka, Sumida, Tokyo, 131-8501, Japan
| | - Junko Suzuki
- Biological Science Research, Kao Corporation, 2606 Akabane, Ichikai-machi, Haga-gun, Tochigi, 321-3497, Japan
| | - Chika Suzukamo
- Biological ScienceResearch, Kao Corporation, 2-1-3 Bunka, Sumida, Tokyo, 131-8501, Japan
| | - Shinsuke Nirengi
- Division of Preventive Medicine, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, 1-1 Mukaihata-cho, Fukakusa, Fushimi-ku, Kyoto, 612-8555, Japan
| | - Akiko Suganuma
- Division of Preventive Medicine, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, 1-1 Mukaihata-cho, Fukakusa, Fushimi-ku, Kyoto, 612-8555, Japan
| | - Akira Shimotoyodome
- Biological Science Research, Kao Corporation, 2606 Akabane, Ichikai-machi, Haga-gun, Tochigi, 321-3497, Japan
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22
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Chia CW, Egan JM. Incretins in obesity and diabetes. Ann N Y Acad Sci 2019; 1461:104-126. [PMID: 31392745 PMCID: PMC10131087 DOI: 10.1111/nyas.14211] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 07/13/2019] [Accepted: 07/18/2019] [Indexed: 12/11/2022]
Abstract
Incretins are hormones secreted from enteroendocrine cells after nutrient intake that stimulate insulin secretion from β cells in a glucose-dependent manner. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the only two known incretins. Dysregulation of incretin secretion and actions are noted in diseases such as obesity and diabetes. In this review, we first summarize our traditional understanding of the physiology of GIP and GLP-1, and our current knowledge of the relationships between GIP and GLP-1 and obesity and diabetes. Next, we present the results from major randomized controlled trials on the use of GLP-1 receptor agonists for managing type 2 diabetes, and emerging data on treating obesity and prediabetes. We conclude with a glimpse of the future with possible complex interactions between nutrients, gut microbiota, the endocannabinoid system, and enteroendocrine cells.
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Affiliation(s)
- Chee W Chia
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Josephine M Egan
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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23
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Sánchez-Tapia M, Martínez-Medina J, Tovar AR, Torres N. Natural and Artificial Sweeteners and High Fat Diet Modify Differential Taste Receptors, Insulin, and TLR4-Mediated Inflammatory Pathways in Adipose Tissues of Rats. Nutrients 2019; 11:nu11040880. [PMID: 31010163 PMCID: PMC6520815 DOI: 10.3390/nu11040880] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/05/2019] [Accepted: 04/17/2019] [Indexed: 02/06/2023] Open
Abstract
It is difficult to know if the cause for obesity is the type of sweetener, high fat (HF) content, or the combination of sweetener and fat. The purpose of the present work was to study different types of sweeteners; in particular, steviol glycosides (SG), glucose, fructose, sucrose, brown sugar, honey, SG + sucrose (SV), and sucralose on the functionality of the adipocyte. Male Wistar rats were fed for four months with different sweeteners or sweetener with HF added. Taste receptors T1R2 and T1R3 were differentially expressed in the tongue and intestine by sweeteners and HF. The combination of fat and sweetener showed an additive effect on circulating levels of GIP and GLP-1 except for honey, SG, and brown sugar. In adipose tissue, sucrose and sucralose stimulated TLR4, and c-Jun N-terminal (JNK). The combination of HF with sweeteners increased NFκB, with the exception of SG and honey. Honey kept the insulin signaling pathway active and the smallest adipocytes in white (WAT) and brown (BAT) adipose tissue and the highest expression of adiponectin, PPARγ, and UCP-1 in BAT. The addition of HF reduced mitochondrial branched-chain amino transferase (BCAT2) branched-chain keto acid dehydrogenase E1 (BCKDH) and increased branched chain amino acids (BCAA) levels by sucrose and sucralose. Our data suggests that the consumption of particular honey maintained functional adipocytes despite the consumption of a HF diet.
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Affiliation(s)
- Mónica Sánchez-Tapia
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City 14080, Mexico.
| | - Jonathan Martínez-Medina
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City 14080, Mexico.
| | - Armando R Tovar
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City 14080, Mexico.
| | - Nimbe Torres
- Departamento de Fisiología de la Nutrición, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City 14080, Mexico.
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24
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An incretin-based tri-agonist promotes superior insulin secretion from murine pancreatic islets via PLC activation. Cell Signal 2018; 51:13-22. [DOI: 10.1016/j.cellsig.2018.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 01/22/2023]
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25
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Fatty Acid-Stimulated Insulin Secretion vs. Lipotoxicity. Molecules 2018; 23:molecules23061483. [PMID: 29921789 PMCID: PMC6100479 DOI: 10.3390/molecules23061483] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 12/29/2022] Open
Abstract
Fatty acid (FA)-stimulated insulin secretion (FASIS) is reviewed here in contrast to type 2 diabetes etiology, resulting from FA overload, oxidative stress, intermediate hyperinsulinemia, and inflammation, all converging into insulin resistance. Focusing on pancreatic islet β-cells, we compare the physiological FA roles with the pathological ones. Considering FAs not as mere amplifiers of glucose-stimulated insulin secretion (GSIS), but as parallel insulin granule exocytosis inductors, partly independent of the KATP channel closure, we describe the FA initiating roles in the prediabetic state that is induced by retardations in the glycerol-3-phosphate (glucose)-promoted glycerol/FA cycle and by the impaired GPR40/FFA1 (free FA1) receptor pathway, specifically in its amplification by the redox-activated mitochondrial phospholipase, iPLA2γ. Also, excessive dietary FAs stimulate intestine enterocyte incretin secretion, further elevating GSIS, even at low glucose levels, thus contributing to diabetic hyperinsulinemia. With overnutrition and obesity, the FA overload causes impaired GSIS by metabolic dysbalance, paralleled by oxidative and metabolic stress, endoplasmic reticulum stress and numerous pro-apoptotic signaling, all leading to decreased β-cell survival. Lipotoxicity is exerted by saturated FAs, whereas ω-3 polyunsaturated FAs frequently exert antilipotoxic effects. FA-facilitated inflammation upon the recruitment of excess M1 macrophages into islets (over resolving M2 type), amplified by cytokine and chemokine secretion by β-cells, leads to an inevitable failure of pancreatic β-cells.
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26
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Kapeluto J, Tchernof A, Biertho L. Surgery for Diabetes: Clinical and Mechanistic Aspects. Can J Diabetes 2018; 41:392-400. [PMID: 28739097 DOI: 10.1016/j.jcjd.2017.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 05/16/2017] [Accepted: 05/24/2017] [Indexed: 01/04/2023]
Abstract
According to the most recent publication by the Canadian Public Health Agency, obesity affects 25% of adults. In addition, there is a clear association between the recent rise in obesity and the increased prevalence of type 2 diabetes. Medical therapy for obesity has shown limited long-term effectiveness, and surgical treatment is now recognized by medical authorities as part of the armamentarium for the management of type 2 diabetes in severely obese patients. The current indications for obesity surgery and postoperative management are reviewed. The choice of surgery should balance expected benefits associated with weight loss (including remission rate of type 2 diabetes), side effects and the risks for early and long-term complications. Long-term outcomes of metabolic surgery for diabetes vary according to the type of surgery (ranging between 20% and 90% remission rates) and the underlying metabolic changes. Several controlled trials have been published in recent years confirming the superiority of metabolic surgery over medical treatment for the management of type 2 diabetes associated with severe obesity. Some of the known underlying mechanisms of action include a combination of caloric restriction, hormonal changes, decreased nutrient absorption and changes in bile acids, microbiota and incretins. Further research is needed to clarify the mechanistic changes associated with each surgical procedure and their respective long-term outcomes.
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Affiliation(s)
- Jordanna Kapeluto
- Department of Bariatric Surgery, Quebec Heart and Lung Institute, Laval University, Quebec City, Quebec, Canada
| | - André Tchernof
- Department of Bariatric Surgery, Quebec Heart and Lung Institute, Laval University, Quebec City, Quebec, Canada
| | - Laurent Biertho
- Department of Bariatric Surgery, Quebec Heart and Lung Institute, Laval University, Quebec City, Quebec, Canada.
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27
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Human GIP(3-30)NH 2 inhibits G protein-dependent as well as G protein-independent signaling and is selective for the GIP receptor with high-affinity binding to primate but not rodent GIP receptors. Biochem Pharmacol 2018; 150:97-107. [PMID: 29378179 DOI: 10.1016/j.bcp.2018.01.040] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/22/2018] [Indexed: 12/21/2022]
Abstract
GIP(3-30)NH2 is a high affinity antagonist of the GIP receptor (GIPR) in humans inhibiting insulin secretion via G protein-dependent pathways. However, its ability to inhibit G protein-independent signaling is unknown. Here we determine its action on arrestin-recruitment and receptor internalization in recombinant cells. As GIP is adipogenic, we evaluate the inhibitory actions of GIP(3-30)NH2 in human adipocytes. Finally, we determine the receptor selectivity of GIP(3-30)NH2 among other human and animal GPCRs. cAMP accumulation and β-arrestin 1 and 2 recruitment were studied in transiently transfected HEK293 cells and real-time internalization in transiently transfected HEK293A and in HEK293A β-arrestin 1 and 2 knockout cells. Furthermore, human subcutaneous adipocytes were assessed for cAMP accumulation following ligand stimulation. Competition binding was examined in transiently transfected COS-7 cells using human 125I-GIP(3-30)NH2. The selectivity of human GIP(3-30)NH2 was examined by testing for agonistic and antagonistic properties on 62 human GPCRs. Human GIP(3-30)NH2 inhibited GIP(1-42)-induced cAMP and β-arrestin 1 and 2 recruitment on the human GIPR and Schild plot analysis showed competitive antagonism with a pA2 and Hill slope of 16.8 nM and 1.11 ± 0.02 in cAMP, 10.6 nM and 1.15 ± 0.05 in β-arrestin 1 recruitment, and 10.2 nM and 1.06 ± 0.05 in β-arrestin 2 recruitment. Efficient internalization of the GIPR was dependent on the presence of either β-arrestin 1 or 2. Moreover, GIP(3-30)NH2 inhibited GIP(1-42)-induced internalization in a concentration-dependent manner and notably also inhibited GIP-mediated signaling in human subcutaneous adipocytes. Finally, the antagonist was established as GIPR selective among 62 human GPCRs being species-specific with high affinity binding to the human and non-human primate (Macaca fascicularis) GIPRs, and low affinity binding to the rat and mouse GIPRs (Kd values of 2.0, 2.5, 31.6 and 100 nM, respectively). In conclusion, human GIP(3-30)NH2 is a selective and species-specific GIPR antagonist with broad inhibition of signaling and internalization in transfected cells as well as in human adipocytes.
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28
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Gasbjerg LS, Gabe MBN, Hartmann B, Christensen MB, Knop FK, Holst JJ, Rosenkilde MM. Glucose-dependent insulinotropic polypeptide (GIP) receptor antagonists as anti-diabetic agents. Peptides 2018; 100:173-181. [PMID: 29412817 DOI: 10.1016/j.peptides.2017.11.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 01/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is an intestinal hormone with a broad range of physiological actions. In the postprandial state, the hormone stimulates insulin secretion and during eu- and hypoglycemia, it stimulates glucagon secretion. In addition, GIP increases triacylglycerol (TAG) uptake in adipose tissue and decreases bone resorption. However, the importance of these actions in humans are not clearly understood as a specific GIP receptor (GIPR) antagonist - an essential tool to study GIP physiology - has been missing. Several different GIPR antagonists have been identified comprising both peptides, vaccines against GIP, GIP antibodies or antibodies against the GIPR. However, most of these have only been tested in rodents. In vitro, N- and C-terminally truncated GIP variants are potent and efficacious GIPR antagonists. Recently, GIP(3-30)NH2, a naturally occurring peptide, was shown to block the GIPR in humans and decrease GIP-induced insulin secretion as well as adipose tissue blood flow and TAG uptake. So far, there are no studies with a GIPR antagonist in patients with type 2 diabetes (T2D), but because the elevations in fasting plasma glucagon and paradoxical postprandial glucagon excursions, seen in patients with T2D, are aggravated by GIP, a GIPR antagonist could partly alleviate this and possibly improve the fasting and postprandial glycemia. Since the majority of patients with T2D are overweight, inhibition of GIP-induced fat deposition may be beneficial as well. Here we summarize the studies of GIPR antagonists and discuss the therapeutic potential of the GIP system in humans.
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Affiliation(s)
- Lærke Smidt Gasbjerg
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.
| | - Maria Buur Nordskov Gabe
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel Bring Christensen
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Filip Krag Knop
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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29
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Abstract
The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) have attracted considerable scientific and clinical interest due largely to their insulin-releasing and glucose-lowering properties. Indeed, GLP-1-based therapies are now key treatment options for many people with diabetes worldwide. In contrast, GIP-based agents have yet to reach the clinic based primarily on the impaired insulinotropic action of GIP observed in people with diabetes. Nevertheless, GIP is a key physiological regulator of insulin secretion and stable forms of GIP show much promise in rodent models to alleviate diabetes-obesity. Recent studies suggest that GIP may have an important role to play in a combination therapeutic approach or bioengineered with other gut peptides. Moreover, recent experimental studies indicate that incretins also exert pleiotropic effects in regions of the brain associated with learning and memory, thereby supporting preclinical data demonstrating that incretin-based drugs improve cognitive function. This review article, based on the RD Lawrence Lecture presented at Diabetes UK Annual Professional Conference (2017), provides a brief overview of incretins with a major focus on GIP, the development of designer GIP analogues, and how these molecules can improve cognition. Thus, incretins can be considered as 'the intelligent hormones' and may hold the key to successfully treating the alarming rise in neurodegenerative disorders.
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Affiliation(s)
- V A Gault
- School of Biomedical Sciences, University of Ulster, Coleraine, UK
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30
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Liao WL, Lee WJ, Chen CC, Lu CH, Chen CH, Chou YC, Lee IT, Sheu WHH, Wu JY, Yang CF, Wang CH, Tsai FJ. Pharmacogenetics of dipeptidyl peptidase 4 inhibitors in a Taiwanese population with type 2 diabetes. Oncotarget 2017; 8:18050-18058. [PMID: 28160554 PMCID: PMC5392306 DOI: 10.18632/oncotarget.14951] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 01/03/2017] [Indexed: 12/22/2022] Open
Abstract
Dipeptidyl peptidase-4 (DPP-4) inhibitors are oral anti-hyperglycemic drugs enabling effective glycemic control in type 2 diabetes (T2D). Despite DPP-4 inhibitors' advantages, the patients' therapeutic response varies. In this retrospective cohort study, 171 Taiwanese patients with T2D were classified as sensitive or resistant to treatment based on the mean change in HbA1c levels. Using an assumption-free genome-wide association study, 45 single nucleotide polymorphisms (SNPs) involved in the therapeutic response to DPP-4 inhibitors (P < 1 × 10-4) were identified at or near PRKD1, CNTN3, ASK, and LOC10537792. A SNP located within the fourth intron of PRKD1 (rs57803087) was strongly associated with DPP-4 inhibitor response (P = 3.2 × 10-6). This is the first pharmacogenomics study on DPP-4 inhibitor treatment for diabetes in a Taiwanese population. Our data suggest that genes associated with β-cell function and apoptosis are involved in the therapeutic effect of DPP-4 inhibitors, even in the presence of additional oral anti-diabetic drugs. Our findings provide information on how genetic variants influence drug response and may benefit the development of personalized medicine.
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Affiliation(s)
- Wen-Ling Liao
- Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan.,Center for Personalized Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Wen-Jane Lee
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Ching-Chu Chen
- Division of Endocrinology and Metabolism, Department of Medicine, China Medical University Hospital, Taichung, Taiwan.,School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Chieh Hsiang Lu
- Department of Internal Medicine, Ditmanson Medical Foundation, Chiayi Christian Hospital, Chiayi City, Taiwan.,Department of Nursing, College of Nursing and Health Sciences, DAYEH University, Taiwan.,Department of Business management, College of Management, National Chung Cheng University, Taiwan
| | - Chien-Hsiun Chen
- School of Chinese Medicine, China Medical University, Taichung, Taiwan.,National Center for Genome Medicine, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Chun Chou
- National Center for Genome Medicine, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - I-Te Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taichung Veterans Hospital, Taichung, Taiwan.,School of Medicine, Chung Shan Medical University, Taichung, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Wayne H-H Sheu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Taichung Veterans Hospital, Taichung, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan.,School of Medicine, National Defense Medical Center, Taipei, Taiwan.,Institute of Medical Technology, National Chung-Hsing University, Taichung, Taiwan
| | - Jer-Yuarn Wu
- School of Chinese Medicine, China Medical University, Taichung, Taiwan.,National Center for Genome Medicine, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chi-Fan Yang
- National Center for Genome Medicine, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chung-Hsing Wang
- Department of Genetics and Metabolism, Children's Hospital of China Medical University, Taichung, Taiwan.,School of Medicine, China Medical University, Taichung, Taiwan
| | - Fuu-Jen Tsai
- School of Chinese Medicine, China Medical University, Taichung, Taiwan.,Department of Medical Genetics, China Medical University Hospital, Taichung, Taiwan.,Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan
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31
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Thondam SK, Daousi C, Wilding JPH, Holst JJ, Ameen GI, Yang C, Whitmore C, Mora S, Cuthbertson DJ. Glucose-dependent insulinotropic polypeptide promotes lipid deposition in subcutaneous adipocytes in obese type 2 diabetes patients: a maladaptive response. Am J Physiol Endocrinol Metab 2017; 312:E224-E233. [PMID: 28073779 DOI: 10.1152/ajpendo.00347.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/28/2016] [Accepted: 01/02/2017] [Indexed: 12/19/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) beyond its insulinotropic effects may regulate postprandial lipid metabolism. Whereas the insulinotropic action of GIP is known to be impaired in type 2 diabetes mellitus (T2DM), its adipogenic effect is unknown. We hypothesized that GIP is anabolic in human subcutaneous adipose tissue (SAT) promoting triacylglycerol (TAG) deposition through reesterification of nonesterified fatty acids (NEFA), and this effect may differ according to obesity status or glucose tolerance. Twenty-three subjects categorized into four groups, normoglycemic lean (n = 6), normoglycemic obese (n = 6), obese with impaired glucose regulation (IGR; n = 6), and obese T2DM (n = 5), participated in a double-blind, randomized, crossover study involving a hyperglycemic clamp with a 240-min GIP infusion (2 pmol·kg-1·min-1) or normal saline. Insulin, NEFA, SAT-TAG content, and gene expression of key lipogenic enzymes were determined before and immediately after GIP/saline infusions. GIP lowered NEFA concentrations in the obese T2DM group despite diminished insulinotropic activity (mean NEFA AUC0-4 h ± SE, 41,992 ± 9,843 µmol·l-1·min-1 vs. 71,468 ± 13,605 with placebo, P = 0.039, 95% CI: 0.31-0.95). Additionally, GIP increased SAT-TAG in obese T2DM (1.78 ± 0.4 vs 0.86 ± 0.1-fold with placebo, P = 0.043, 95% CI: 0.1-1.8). Such effect with GIP was not observed in other three groups despite greater insulinotropic activity. Reduction in NEFA concentration with GIP correlated with adipose tissue insulin resistance for all subjects (Pearson, r = 0.56, P = 0.005). There were no significant gene expression changes in key SAT lipid metabolism enzymes. In conclusion, GIP appears to promote fat accretion and thus may exacerbate obesity and insulin resistance in T2DM.
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Affiliation(s)
- Sravan K Thondam
- Obesity and Endocrinology Research Group, University Hospital Aintree, Liverpool, United Kingdom
| | - Christina Daousi
- Obesity and Endocrinology Research Group, University Hospital Aintree, Liverpool, United Kingdom
| | - John P H Wilding
- Obesity and Endocrinology Research Group, University Hospital Aintree, Liverpool, United Kingdom
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Jens J Holst
- NovoNordisk Foundation Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gulizar I Ameen
- Department of Cellular and Molecular Physiology University of Liverpool, Liverpool, United Kingdom; and
| | - Chenjing Yang
- Department of Cellular and Molecular Physiology University of Liverpool, Liverpool, United Kingdom; and
| | - Catherine Whitmore
- Obesity and Endocrinology Research Group, University Hospital Aintree, Liverpool, United Kingdom
| | - Silvia Mora
- Department of Cellular and Molecular Physiology University of Liverpool, Liverpool, United Kingdom; and
| | - Daniel J Cuthbertson
- Obesity and Endocrinology Research Group, University Hospital Aintree, Liverpool, United Kingdom
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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32
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Finan B, Müller TD, Clemmensen C, Perez-Tilve D, DiMarchi RD, Tschöp MH. Reappraisal of GIP Pharmacology for Metabolic Diseases. Trends Mol Med 2016; 22:359-376. [DOI: 10.1016/j.molmed.2016.03.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 12/31/2022]
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Increased plasma levels of glucose-dependent insulinotropic polypeptide are associated with decreased postprandial energy expenditure after modern Japanese meals. Eur J Nutr 2016; 56:1693-1705. [PMID: 27112963 PMCID: PMC5486637 DOI: 10.1007/s00394-016-1216-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 04/15/2016] [Indexed: 12/14/2022]
Abstract
Purpose The nutritional changes that have accompanied the modernization of Japanese dietary patterns have led to significant increases in the number of people who are overweight or obese. This study aimed to clarify the effects of these nutritional changes on postprandial energy expenditure and the release of metabolism-regulating hormones. Methods The total daily energy content (20 % breakfast, 40 % lunch, and 40 % dinner) and macronutrient composition (carbohydrate/fat/protein) was 8807.3 kJ and 364.3:30.1:66.4 (g) for the traditional test diet and 9217.6 kJ and 331.7:66.1:76.9 (g) for the modern test diet. In experiment 1, nine healthy Japanese men participated in a crossover study during which they ingested a test diet comprising three meals; postprandial blood parameters were measured after each meal. In experiment 2, another ten men participated in a crossover study during which they ingested 2 meals, after which metabolic responses and blood variables were evaluated. Results The modern diet induced greater blood levels of glucose-dependent insulinotropic polypeptide (GIP) and ghrelin than did the traditional diet. The expected increase in postprandial energy expenditure (∆REE) tended to be dampened after the modern compared with the traditional diet. GIP was inversely correlated with ∆REE after lunch, and ghrelin was positively associated with ∆REE. Conclusion Both GIP and ghrelin are robust indicators of postprandial energy expenditure. The nutritional changes accompanying the modernization of Japanese dietary patterns may increase the levels of the anabolic intestinal hormone GIP, which is associated with ∆REE, in the Japanese population. The contribution of an increased ghrelin concentration to the decreased ∆REE after the modern diet warrants further investigation.
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34
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Suh S, Kim MY, Kim SK, Hur KY, Park MK, Kim DK, Cho NH, Lee MK. Glucose-Dependent Insulinotropic Peptide Level Is Associated with the Development of Type 2 Diabetes Mellitus. Endocrinol Metab (Seoul) 2016; 31:134-41. [PMID: 26676334 PMCID: PMC4803549 DOI: 10.3803/enm.2016.31.1.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/04/2015] [Accepted: 09/15/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Incretin hormone levels as a predictor of type 2 diabetes mellitus have not been fully investigated. Therefore, we measured incretin hormone levels to examine the relationship between circulating incretin hormones, diabetes, and future diabetes development in this study. METHODS A nested case-control study was conducted in a Korean cohort. The study included the following two groups: the control group (n=149), the incident diabetes group (n=65). Fasting total glucagon-like peptide-1 (GLP-1) and total glucose-dependent insulinotropic peptide (GIP) levels were measured and compared between these groups. RESULTS Fasting total GIP levels were higher in the incident diabetes group than in the control group (32.64±22.68 pmol/L vs. 25.54±18.37 pmol/L, P=0.034). There was no statistically significant difference in fasting total GLP-1 levels between groups (1.14±1.43 pmol/L vs. 1.39±2.13 pmol/L, P=0.199). In multivariate analysis, fasting total GIP levels were associated with an increased risk of diabetes (odds ratio, 1.005; P=0.012) independent of other risk factors. CONCLUSION Fasting total GIP levels may be a risk factor for the development of type 2 diabetes mellitus. This association persisted even after adjusting for other metabolic parameters such as elevated fasting glucose, hemoglobin A1c, and obesity in the pre-diabetic period.
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Affiliation(s)
- Sunghwan Suh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dong-A Medical Center, Dong-A University College of Medicine, Busan, Korea
| | - Mi Yeon Kim
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Soo Kyoung Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Kyu Yeon Hur
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Mi Kyoung Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dong-A Medical Center, Dong-A University College of Medicine, Busan, Korea
| | - Duk Kyu Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Dong-A Medical Center, Dong-A University College of Medicine, Busan, Korea
| | - Nam H Cho
- Department of Preventive Medicine, Ajou University School of Medicine, Suwon, Korea.
| | - Moon Kyu Lee
- Division of Endocrinology and Metabolism, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
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Moffett RC, Vasu S, Flatt PR. Functional GIP receptors play a major role in islet compensatory response to high fat feeding in mice. Biochim Biophys Acta Gen Subj 2015; 1850:1206-14. [PMID: 25688757 DOI: 10.1016/j.bbagen.2015.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/30/2015] [Accepted: 02/09/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Consumption of high fat diet and insulin resistance induce significant changes in pancreatic islet morphology and function essential for maintenance of normal glucose homeostasis. We have used incretin receptor null mice to evaluate the role of gastric inhibitory polypeptide (GIP) in this adaptive response. METHODS C57BL/6 and GIPRKO mice were fed high fat diet for 45 weeks from weaning. Changes of pancreatic islet morphology were assessed by immunohistochemistry. Body fat, glucose, insulin, glucagon, glucagon-like peptide 1 (GLP-1) and GIP were assessed by routine assays. RESULTS Compared with normal diet controls, high fat fed C57BL/6 mice exhibited increased body fat, hyperinsulinaemia and insulin resistance, associated with decreased pancreatic glucagon, unchanged pancreatic GLP-1 and marked increases of insulin, islet number, islet size and both beta- and alpha-cell areas. Beta cell proliferation and apoptosis were increased under high fat feeding, but the overall effect favoured enhanced beta cell mass. A broadly similar pattern of change was observed in high fat fed GIPRKO mice but islet compensation was severely impaired in every respect. The inability to enhance beta cell proliferation was associated with the depletion of pancreatic GLP-1 and lack of hyperinsulinaemic response, resulting in non-fasting hyperglycaemia. GIP and GLP-1 were expressed in islets of all groups of mice but high fat fed GIPRKO mice displayed decreased numbers of GLP-1 containing alpha cells plus non-functional enhancement of pancreatic GIP content. GENERAL SIGNIFICANCE These data suggest that GIP released from islet alpha-cells and intestinal K-cells plays an important role in islet adaptations to high fat feeding.
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Affiliation(s)
- R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Cromore Road, Coleraine BT52 1SA, Northern Ireland, UK.
| | - Srividya Vasu
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Cromore Road, Coleraine BT52 1SA, Northern Ireland, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Cromore Road, Coleraine BT52 1SA, Northern Ireland, UK
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Li X, Jiang L, Yang M, Wu Y, Sun S, Sun J. GLP-1 receptor agonist increases the expression of CTRP3, a novel adipokine, in 3T3-L1 adipocytes through PKA signal pathway. J Endocrinol Invest 2015; 38:73-9. [PMID: 25149084 DOI: 10.1007/s40618-014-0156-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 08/07/2014] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To investigate the effects of Exendin-4 (Ex-4), a glucagon-like peptide-1 (GLP-1) receptor agonist, on the expression of C1q/TNF-related protein-3 (CTRP3), a novel adipokine, in 3T3-L1 adipocytes. The role of protein kinase A (PKA) signal pathway in the effects was also investigated. METHODS The mRNA and protein expressions of CTRP3 in 3T3-L1 adiocytes were detected by real-time polymerase chain reaction and western blot, respectively. Exendin-fragment 9-39 (Ex-9), a specific GLP-1 receptor antagonist, and H89, a selective antagonist of PKA, were used to confirm the signal pathway of Ex-4 on CTRP3. RESULTS 2.5 or 5.0 nmol/l Ex-4 treatment for 8 h increased the expressions of CTRP3 mRNA and protein as well as PKA protein in 3T3-L1 adipocytes significantly, while Ex-9 or H89 blocked the up-regulation of CTRP3 expression induced by Ex-4 completely. CONCLUSION GLP-1 receptor agonist increases the expression of CTRP3 mRNA and protein in 3T3-L1 adipocytes via PKA signal pathway.
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Affiliation(s)
- X Li
- Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China.
| | - L Jiang
- Department of Internal Medicine, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - M Yang
- Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Y Wu
- Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - S Sun
- Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - J Sun
- Department of Endocrinology, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
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