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Yuan YC, Wang H, Jiang ZJ, Liu C, Li Q, Zhou SR, Yang JK. Potassium voltage-gated channel subfamily H member 2 (KCNH2) is a promising target for incretin secretagogue therapies. Signal Transduct Target Ther 2024; 9:207. [PMID: 39128897 PMCID: PMC11317495 DOI: 10.1038/s41392-024-01923-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 06/16/2024] [Accepted: 07/14/2024] [Indexed: 08/13/2024] Open
Abstract
Derived from enteroendocrine cells (EECs), glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are pivotal incretin hormones crucial for blood glucose regulation. Medications of GLP-1 analogs and GLP-1 receptor activators are extensively used in the treatment of type 2 diabetes (T2D) and obesity. However, there are currently no agents to stimulate endogenous incretin secretion. Here, we find the pivotal role of KCNH2 potassium channels in the regulation of incretin secretion. Co-localization of KCNH2 with incretin-secreting EECs in the intestinal epithelium of rodents highlights its significance. Gut epithelial cell-specific KCNH2 knockout in mice improves glucose tolerance and increases oral glucose-triggered GLP-1 and GIP secretion, particularly GIP. Furthermore, KCNH2-deficient primary intestinal epithelial cells exhibit heightened incretin, especially GIP secretion upon nutrient stimulation. Mechanistically, KCNH2 knockdown in EECs leads to reduced K+ currents, prolonged action potential duration, and elevated intracellular calcium levels. Finally, we found that dofetilide, a KCNH2-specific inhibitor, could promote incretin secretion in enteroendocrine STC-1 cells in vitro and in hyperglycemic mice in vivo. These findings elucidate, for the first time, the mechanism and application of KCNH2 in regulating incretin secretion by EECs. Given the therapeutic promise of GLP-1 and GIP in diabetes and obesity management, this study advances our understanding of incretin regulation, paving the way for potential incretin secretagogue therapies in the treatment of diabetes and obesity.
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Affiliation(s)
- Ying-Chao Yuan
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China
| | - Hao Wang
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China.
| | - Ze-Ju Jiang
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China
| | - Chang Liu
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Qi Li
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China
| | - Si-Rui Zhou
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China
| | - Jin-Kui Yang
- Beijing Key Laboratory of Diabetes Research and Care, Department of Endocrinology and Metabolism, Beijing Diabetes Institute, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
- Laboratory for Clinical Medicine, Capital Medical University, Beijing, 100069, China.
- Subcenter of State Key Laboratory of Kidney Disease, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
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2
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Carr ER, Higgins PB, McClenaghan NH, Flatt PR, McCloskey AG. MicroRNA regulation of islet and enteroendocrine peptides: Physiology and therapeutic implications for type 2 diabetes. Peptides 2024; 176:171196. [PMID: 38492669 DOI: 10.1016/j.peptides.2024.171196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/05/2024] [Accepted: 03/14/2024] [Indexed: 03/18/2024]
Abstract
The pathogenesis of type 2 diabetes (T2D) is associated with dysregulation of glucoregulatory hormones, including both islet and enteroendocrine peptides. Microribonucleic acids (miRNAs) are short noncoding RNA sequences which post transcriptionally inhibit protein synthesis by binding to complementary messenger RNA (mRNA). Essential for normal cell activities, including proliferation and apoptosis, dysregulation of these noncoding RNA molecules have been linked to several diseases, including diabetes, where alterations in miRNA expression within pancreatic islets have been observed. This may occur as a compensatory mechanism to maintain beta-cell mass/function (e.g., downregulation of miR-7), or conversely, lead to further beta-cell demise and disease progression (e.g., upregulation of miR-187). Thus, targeting miRNAs has potential for novel diagnostic and therapeutic applications in T2D. This is reinforced by the success seen to date with miRNA-based therapeutics for other conditions currently in clinical trials. In this review, differential expression of miRNAs in human islets associated with T2D will be discussed along with further consideration of their effects on the production and secretion of islet and incretin hormones. This analysis further unravels the therapeutic potential of miRNAs and offers insights into novel strategies for T2D management.
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Affiliation(s)
- E R Carr
- Department of Life and Physical Sciences, Atlantic Technology University, Donegal, Ireland; Department of Life Sciences, Atlantic Technological University, Sligo, Ireland
| | - P B Higgins
- Department of Life and Physical Sciences, Atlantic Technology University, Donegal, Ireland
| | - N H McClenaghan
- Department of Life Sciences, Atlantic Technological University, Sligo, Ireland
| | - P R Flatt
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - A G McCloskey
- Department of Life and Physical Sciences, Atlantic Technology University, Donegal, Ireland.
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3
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Liu H, Xiao H, Lin S, Zhou H, Cheng Y, Xie B, Xu D. Effect of gut hormones on bone metabolism and their possible mechanisms in the treatment of osteoporosis. Front Pharmacol 2024; 15:1372399. [PMID: 38725663 PMCID: PMC11079205 DOI: 10.3389/fphar.2024.1372399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/25/2024] [Indexed: 05/12/2024] Open
Abstract
Bone is a highly dynamic organ that changes with the daily circadian rhythm. During the day, bone resorption is suppressed due to eating, while it increases at night. This circadian rhythm of the skeleton is regulated by gut hormones. Until now, gut hormones that have been found to affect skeletal homeostasis include glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2), glucose-dependent insulinotropic polypeptide (GIP), and peptide YY (PYY), which exerts its effects by binding to its cognate receptors (GLP-1R, GLP-2R, GIPR, and Y1R). Several studies have shown that GLP-1, GLP-2, and GIP all inhibit bone resorption, while GIP also promotes bone formation. Notably, PYY has a strong bone resorption-promoting effect. In addition, gut microbiota (GM) plays an important role in maintaining bone homeostasis. This review outlines the roles of GLP-1, GLP-2, GIP, and PYY in bone metabolism and discusses the roles of gut hormones and the GM in regulating bone homeostasis and their potential mechanisms.
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Affiliation(s)
- Hongyu Liu
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Institute of Traditional Chinese Medicine and New Pharmacy Development, Guangdong Medical University, Dongguan, China
| | - Huimin Xiao
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Institute of Traditional Chinese Medicine and New Pharmacy Development, Guangdong Medical University, Dongguan, China
| | - Sufen Lin
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Institute of Traditional Chinese Medicine and New Pharmacy Development, Guangdong Medical University, Dongguan, China
| | - Huan Zhou
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Institute of Traditional Chinese Medicine and New Pharmacy Development, Guangdong Medical University, Dongguan, China
| | - Yizhao Cheng
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Institute of Traditional Chinese Medicine and New Pharmacy Development, Guangdong Medical University, Dongguan, China
| | - Baocheng Xie
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Department of Pharmacy, The 10th Affiliated Hospital of Southern Medical University (Dongguan People’s Hospital), Dongguan, China
| | - Daohua Xu
- Guangdong Key Laboratory for Research and Development of Natural Drugs, Dongguan Key Laboratory of Traditional Chinese Medicine and New Pharmaceutical Development, School of Pharmacy, Guangdong Medical University, Dongguan, China
- Institute of Traditional Chinese Medicine and New Pharmacy Development, Guangdong Medical University, Dongguan, China
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4
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Sicinski KM, Sürmeli D, Du J, Raman VS, Montanari V, Lee M, Harwood BN, Kopin AS, Beinborn M, Kumar K. A Robust Platform for the Molecular Design of Potent, Protease-Stable, Long-Acting GIP Analogues. J Med Chem 2024. [PMID: 38458970 DOI: 10.1021/acs.jmedchem.4c00111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Glucose-dependent insulinotropic peptide (GIP) is a 42-amino acid peptide hormone that regulates postprandial glucose levels. GIP binds to its cognate receptor, GIPR, and mediates metabolic physiology by improved insulin sensitivity, β-cell proliferation, increased energy consumption, and stimulated glucagon secretion. Dipeptidyl peptidase-4 (DPP4) catalyzes the rapid inactivation of GIP within 6 min in vivo. Here, we report a molecular platform for the design of GIP analogues that are refractory to DPP4 action and exhibit differential activation of the receptor, thus offering potentially hundreds of GIP-based compounds to fine-tune pharmacology. The lead compound from our studies, which harbored a combination of N-terminal alkylation and side-chain lipidation, was equipotent and retained full efficacy at GIPR as the native peptide, while being completely refractory toward DPP4, and was resistant to trypsin. The GIP analogue identified from these studies was further evaluated in vivo and is one of the longest-acting GIPR agonists to date.
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Affiliation(s)
- Kathleen M Sicinski
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Damla Sürmeli
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Jasper Du
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Venkata S Raman
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Vittorio Montanari
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Minhee Lee
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Benjamin N Harwood
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, United States
| | - Alan S Kopin
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, United States
| | - Martin Beinborn
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
- Molecular Pharmacology Research Center, Tufts Medical Center, Boston, Massachusetts 02111, United States
| | - Krishna Kumar
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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5
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Wibawa IDN, Mariadi IK, Somayana G, Krisnawardani Kumbara CIY, Sindhughosa DA. Diabetes and fatty liver: Involvement of incretin and its benefit for fatty liver management. World J Diabetes 2023; 14:549-559. [PMID: 37273247 PMCID: PMC10237000 DOI: 10.4239/wjd.v14.i5.549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 02/02/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
Fatty liver disease is defined as liver condition characterized by hepatic steatosis, closely related to pathological conditions in type 2 diabetes and obesity. The high prevalence of fatty liver disease in obese patients with type 2 diabetes reached 70%, reflecting the importance of these conditions with fatty liver. Although the exact pathological mechanism of fatty liver disease, specifically non-alcoholic fatty liver disease (NAFLD) remains not completely revealed, insulin resistance is suggested as the major mechanism that bridged the development of NAFLD. Indeed, loss of the incretin effect leads to insulin resistance. Since incretin is closely related to insulin resistance and the resistance of insulin associated with the development of fatty liver disease, this pathway suggested a potential me-chanism that explains the association between type 2 diabetes and NAFLD. Furthermore, recent studies indicated that NAFLD is associated with impaired glucagon-like peptide-1, resulting in decreased incretin effect. Nevertheless, improving the incretin effect becomes a reasonable approach to manage fatty liver disease. This review elucidates the involvement of incretin in fatty liver disease and recent studies of incretin as the management for fatty liver disease.
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Affiliation(s)
- I Dewa Nyoman Wibawa
- Department of Internal Medicine, Gastroentero-hepatology Division, Udayana University, Faculty of Medicine, Denpasar 80233, Bali, Indonesia
| | - I Ketut Mariadi
- Department of Internal Medicine, Gastroentero-hepatology Division, Udayana University, Faculty of Medicine, Denpasar 80233, Bali, Indonesia
| | - Gde Somayana
- Department of Internal Medicine, Gastroentero-hepatology Division, Udayana University, Faculty of Medicine, Denpasar 80233, Bali, Indonesia
| | | | - Dwijo Anargha Sindhughosa
- Internal Medicine Resident, Udayana University, Faculty of Medicine, Denpasar 80233, Bali, Indonesia
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6
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Hammoud R, Drucker DJ. Beyond the pancreas: contrasting cardiometabolic actions of GIP and GLP1. Nat Rev Endocrinol 2023; 19:201-216. [PMID: 36509857 DOI: 10.1038/s41574-022-00783-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/17/2022] [Indexed: 12/14/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP1) exhibit incretin activity, meaning that they potentiate glucose-dependent insulin secretion. The emergence of GIP receptor (GIPR)-GLP1 receptor (GLP1R) co-agonists has fostered growing interest in the actions of GIP and GLP1 in metabolically relevant tissues. Here, we update concepts of how these hormones act beyond the pancreas. The actions of GIP and GLP1 on liver, muscle and adipose tissue, in the control of glucose and lipid homeostasis, are discussed in the context of plausible mechanisms of action. Both the GIPR and GLP1R are expressed in the central nervous system, wherein receptor activation produces anorectic effects enabling weight loss. In preclinical studies, GIP and GLP1 reduce atherosclerosis. Furthermore, GIPR and GLP1R are expressed within the heart and immune system, and GLP1R within the kidney, revealing putative mechanisms linking GIP and GLP1R agonism to cardiorenal protection. We interpret the clinical and mechanistic data obtained for different agents that enable weight loss and glucose control for the treatment of obesity and type 2 diabetes mellitus, respectively, by activating or blocking GIPR signalling, including the GIPR-GLP1R co-agonist tirzepatide, as well as the GIPR antagonist-GLP1R agonist AMG-133. Collectively, we update translational concepts of GIP and GLP1 action, while highlighting gaps, areas of uncertainty and controversies meriting ongoing investigation.
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Affiliation(s)
- Rola Hammoud
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Daniel J Drucker
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
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7
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de Laat MA, Fitzgerald DM. Equine metabolic syndrome: Role of the enteroinsular axis in the insulin response to oral carbohydrate. Vet J 2023; 294:105967. [PMID: 36858344 DOI: 10.1016/j.tvjl.2023.105967] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/17/2023] [Accepted: 02/26/2023] [Indexed: 03/02/2023]
Abstract
Equine insulin dysregulation (ID) comprises amplified insulin responses to oral carbohydrates or insulin resistance, or both, which leads to sustained or periodic hyperinsulinaemia. Hyperinsulinaemia is important in horses because of its clear association with laminitis risk, and the gravity of this common sequela justifies the need for a better understanding of insulin and glucose homoeostasis in this species. Post-prandial hyperinsulinaemia is the more commonly identified component of ID and is diagnosed using tests that include an assessment of the gastrointestinal tract (GIT). There are several factors present in the GIT that either directly, or indirectly, enhance insulin secretion from the endocrine pancreas, and these factors are collectively referred to as the enteroinsular axis (EIA). A role for key components of the EIA, such as the incretin peptides glucagon-like peptide-1 and 2, in the pathophysiology of ID has been investigated in horses. By comparison, the function (and even existence) of many EIA peptides of potential importance, such as glicentin and oxyntomodulin, remains unexplored. The incretins that have been examined all increase insulin responses to oral carbohydrate through one or more mechanisms. This review presents what is known about the EIA in horses, and discusses how it might contribute to ID, then compares this to current understanding derived from the extensive studies undertaken in other species. Future directions for research are discussed and knowledge gaps that should be prioritised are suggested.
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Affiliation(s)
- Melody A de Laat
- School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane 4000, Australia.
| | - Danielle M Fitzgerald
- School of Biology and Environmental Science, Faculty of Science, Queensland University of Technology, Brisbane 4000, Australia
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8
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Khan D, Moffett RC, Flatt PR, Tarasov AI. Classical and non-classical islet peptides in the control of β-cell function. Peptides 2022; 150:170715. [PMID: 34958851 DOI: 10.1016/j.peptides.2021.170715] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 11/25/2021] [Accepted: 12/17/2021] [Indexed: 12/25/2022]
Abstract
The dual role of the pancreas as both an endocrine and exocrine gland is vital for food digestion and control of nutrient metabolism. The exocrine pancreas secretes enzymes into the small intestine aiding digestion of sugars and fats, whereas the endocrine pancreas secretes a cocktail of hormones into the blood, which is responsible for blood glucose control and regulation of carbohydrate, protein and fat metabolism. Classical islet hormones, insulin, glucagon, pancreatic polypeptide and somatostatin, interact in an autocrine and paracrine manner, to fine-tube the islet function and insulin secretion to the needs of the body. Recently pancreatic islets have been reported to express a number of non-classical peptide hormones involved in metabolic signalling, whose major production site was believed to reside outside pancreas, e.g. in the small intestine. We highlight the key non-classical islet peptides, and consider their involvement, together with established islet hormones, in regulation of stimulus-secretion coupling as well as proliferation, survival and transdifferentiation of β-cells. We furthermore focus on the paracrine interaction between classical and non-classical islet hormones in the maintenance of β-cell function. Understanding the functional relationships between these islet peptides might help to develop novel, more efficient treatments for diabetes and related metabolic disorders.
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Affiliation(s)
- Dawood Khan
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK.
| | - R Charlotte Moffett
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Andrei I Tarasov
- Biomedical Sciences Research Institute, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
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9
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Jonik S, Marchel M, Grabowski M, Opolski G, Mazurek T. Gastrointestinal Incretins-Glucose-Dependent Insulinotropic Polypeptide (GIP) and Glucagon-like Peptide-1 (GLP-1) beyond Pleiotropic Physiological Effects Are Involved in Pathophysiology of Atherosclerosis and Coronary Artery Disease-State of the Art. BIOLOGY 2022; 11:biology11020288. [PMID: 35205155 PMCID: PMC8869592 DOI: 10.3390/biology11020288] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 02/06/2023]
Abstract
Simple Summary The presented manuscript contains the most current and extensive summary of the role of the most predominant gastrointestinal hormones—GIP and GLP-1 in the pathophysiology of atherosclerosis and coronary artery disease both in animals and humans. We have described GIP and GLP-1 as (1) expressed in many human tissues, (2) emphasized relationship between GIP and GLP-1 and inflammation, (3) highlighted importance of GIP and GLP-1-dependent pathways in atherosclerosis and coronary artery disease and (4) proved that GIP and GLP-1 could be used as markers of incidence, clinical course and recurrence of coronary artery disease, and related to extent and severity of atherosclerosis and myocardial ischemia. Our initial review may state a cornerstone for the future, however, there are still many unknowns and understatements on this topic. Due to the widespread growing interest for the potential use of incretins in cardiovascular diseases, we think that further research in this direction is desirable. For the future, we would like to recognize GIP and GLP-1 as widely implemented into clinical practice as new biomarkers of atherosclerosis and coronary artery disease. Abstract Coronary artery disease (CAD), which is the manifestation of atherosclerosis in coronary arteries, is the most common single cause of death and is responsible for disabilities of millions of people worldwide. Despite numerous dedicated clinical studies and an enormous effort to develop diagnostic and therapeutic methods, coronary atherosclerosis remains one of the most serious medical problems of the modern world. Hence, new markers are still being sought to identify and manage CAD optimally. Trying to face this problem, we have raised the question of the most predominant gastrointestinal hormones; glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), mainly involved in carbohydrates disorders, could be also used as new markers of incidence, clinical course, and recurrence of CAD and are related to extent and severity of atherosclerosis and myocardial ischemia. We describe GIP and GLP-1 as expressed in many animal and human tissues, known to be connected to inflammation and related to enormous noncardiac and cardiovascular (CV) diseases. In animals, GIP and GLP-1 improve endothelial function and lead to reduced atherosclerotic plaque macrophage infiltration and stabilize atherosclerotic lesions by directly blocking monocyte migration. Moreover, in humans, GIPR activation induces the pro-atherosclerotic factors ET-1 (endothelin-1) and OPN (osteopontin) but also has anti-atherosclerotic effects through secretion of NO (nitric oxide). Furthermore, four large clinical trials showed a significant reduction in composite of CV death, MI, and stroke in long-term follow-up using GLP-1 analogs for DM 2 patients: liraglutide in LEADER, semaglutide in SUSTAIN-6, dulaglutide in REWIND and albiglutide in HARMONY. However, very little is known about GIP metabolism in the acute phase of myocardial ischemia or for stable patients with CAD, which constitutes a direction for future research. This review aims to comprehensively discuss the impact of GIP and GLP-1 on atherosclerosis and CAD and its potential therapeutic implications.
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10
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Lindquist P, Gasbjerg LS, Mokrosinski J, Holst JJ, Hauser AS, Rosenkilde MM. The Location of Missense Variants in the Human GIP Gene Is Indicative for Natural Selection. Front Endocrinol (Lausanne) 2022; 13:891586. [PMID: 35846282 PMCID: PMC9277503 DOI: 10.3389/fendo.2022.891586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/04/2022] [Indexed: 11/16/2022] Open
Abstract
The intestinal hormone, glucose-dependent insulinotropic polypeptide (GIP), is involved in important physiological functions, including postprandial blood glucose homeostasis, bone remodeling, and lipid metabolism. While mutations leading to physiological changes can be identified in large-scale sequencing, no systematic investigation of GIP missense variants has been performed. Here, we identified 168 naturally occurring missense variants in the human GIP genes from three independent cohorts comprising ~720,000 individuals. We examined amino acid changing variants scattered across the pre-pro-GIP peptide using in silico effect predictions, which revealed that the sequence of the fully processed GIP hormone is more protected against mutations than the rest of the precursor protein. Thus, we observed a highly species-orthologous and population-specific conservation of the GIP peptide sequence, suggestive of evolutionary constraints to preserve the GIP peptide sequence. Elucidating the mutational landscape of GIP variants and how they affect the structural and functional architecture of GIP can aid future biological characterization and clinical translation.
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Affiliation(s)
- Peter Lindquist
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lærke Smidt Gasbjerg
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jacek Mokrosinski
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, United States
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Sebastian Hauser
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Alexander Sebastian Hauser, ; Mette Marie Rosenkilde,
| | - Mette Marie Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Alexander Sebastian Hauser, ; Mette Marie Rosenkilde,
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11
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Morrow NM, Hanson AA, Mulvihill EE. Distinct Identity of GLP-1R, GLP-2R, and GIPR Expressing Cells and Signaling Circuits Within the Gastrointestinal Tract. Front Cell Dev Biol 2021; 9:703966. [PMID: 34660576 PMCID: PMC8511495 DOI: 10.3389/fcell.2021.703966] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 08/16/2021] [Indexed: 12/17/2022] Open
Abstract
Enteroendocrine cells directly integrate signals of nutrient content within the gut lumen with distant hormonal responses and nutrient disposal via the production and secretion of peptides, including glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1) and glucagon-like peptide 2 (GLP-2). Given their direct and indirect control of post-prandial nutrient uptake and demonstrated translational relevance for the treatment of type 2 diabetes, malabsorption and cardiometabolic disease, there is significant interest in the locally engaged circuits mediating these metabolic effects. Although several specific populations of cells in the intestine have been identified to express endocrine receptors, including intraepithelial lymphocytes (IELs) and αβ and γδ T-cells (Glp1r+) and smooth muscle cells (Glp2r+), the definitive cellular localization and co-expression, particularly in regards to the Gipr remain elusive. Here we review the current state of the literature and evaluate the identity of Glp1r, Glp2r, and Gipr expressing cells within preclinical and clinical models. Further elaboration of our understanding of the initiating G-protein coupled receptor (GPCR) circuits engaged locally within the intestine and how they become altered with high-fat diet feeding can offer insight into the dysregulation observed in obesity and diabetes.
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Affiliation(s)
- Nadya M Morrow
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Antonio A Hanson
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Erin E Mulvihill
- Energy Substrate Laboratory, University of Ottawa Heart Institute, Ottawa, ON, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.,Montreal Diabetes Research Center CRCHUM-Pavillion R, Montreal, QC, Canada.,Centre for Infection, Immunity and Inflammation, University of Ottawa, Ottawa, ON, Canada
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12
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Nauck MA, Quast DR, Wefers J, Pfeiffer AFH. The evolving story of incretins (GIP and GLP-1) in metabolic and cardiovascular disease: A pathophysiological update. Diabetes Obes Metab 2021; 23 Suppl 3:5-29. [PMID: 34310013 DOI: 10.1111/dom.14496] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 11/27/2022]
Abstract
The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) have their main physiological role in augmenting insulin secretion after their nutrient-induced secretion from the gut. A functioning entero-insular (gut-endocrine pancreas) axis is essential for the maintenance of a normal glucose tolerance. This is exemplified by the incretin effect (greater insulin secretory response to oral as compared to "isoglycaemic" intravenous glucose administration due to the secretion and action of incretin hormones). GIP and GLP-1 have additive effects on insulin secretion. Local production of GIP and/or GLP-1 in islet α-cells (instead of enteroendocrine K and L cells) has been observed, and its significance is still unclear. GLP-1 suppresses, and GIP increases glucagon secretion, both in a glucose-dependent manner. GIP plays a greater physiological role as an incretin. In type 2-diabetic patients, the incretin effect is reduced despite more or less normal secretion of GIP and GLP-1. While insulinotropic effects of GLP-1 are only slightly impaired in type 2 diabetes, GIP has lost much of its acute insulinotropic activity in type 2 diabetes, for largely unknown reasons. Besides their role in glucose homoeostasis, the incretin hormones GIP and GLP-1 have additional biological functions: GLP-1 at pharmacological concentrations reduces appetite, food intake, and-in the long run-body weight, and a similar role is evolving for GIP, at least in animal studies. Human studies, however, do not confirm these findings. GIP, but not GLP-1 increases triglyceride storage in white adipose tissue not only through stimulating insulin secretion, but also by interacting with regional blood vessels and GIP receptors. GIP, and to a lesser degree GLP-1, play a role in bone remodelling. GLP-1, but not GIP slows gastric emptying, which reduces post-meal glycaemic increments. For both GIP and GLP-1, beneficial effects on cardiovascular complications and neurodegenerative central nervous system (CNS) disorders have been observed, pointing to therapeutic potential over and above improving diabetes complications. The recent finding that GIP/GLP-1 receptor co-agonists like tirzepatide have superior efficacy compared to selective GLP-1 receptor agonists with respect to glycaemic control as well as body weight has renewed interest in GIP, which previously was thought to be without any therapeutic potential. One focus of this research is into the long-term interaction of GIP and GLP-1 receptor signalling. A GLP-1 receptor antagonist (exendin [9-39]) and, more recently, a GIP receptor agonist (GIP [3-30] NH2 ) and, hopefully, longer-acting GIP receptor agonists for human use will be helpful tools to shed light on the open questions. A detailed knowledge of incretin physiology and pathophysiology will be a prerequisite for designing more effective incretin-based diabetes drugs.
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Affiliation(s)
- Michael A Nauck
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Daniel R Quast
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Jakob Wefers
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Andreas F H Pfeiffer
- Charité - Universitätsmedizin Berlin, Klinik für Endokrinologie, Stoffwechsel- und Ernährungsmedizin, Berlin, Germany
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13
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Ramzy A, Kieffer TJ. Altered islet prohormone processing: A cause or consequence of diabetes? Physiol Rev 2021; 102:155-208. [PMID: 34280055 DOI: 10.1152/physrev.00008.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues define prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, proIAPP, and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin : C-peptide ratio for progression to type 2 diabetes and elevated proinsulin or proinsulin : C-peptide is predictive for development of type 1 diabetes in at risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP and proinsulin may be an autoantigen in type 1 diabetes. Further, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes, and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.
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Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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14
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Masaki T, Kodera Y, Terasaki M, Fujimoto K, Hirano T, Shichiri M. GIP_HUMAN[22-51] is a new proatherogenic peptide identified by native plasma peptidomics. Sci Rep 2021; 11:14470. [PMID: 34262109 PMCID: PMC8280211 DOI: 10.1038/s41598-021-93862-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/01/2021] [Indexed: 12/25/2022] Open
Abstract
We recently established a new plasma peptidomic technique and comprehensively identified a large number of low-molecular weight and low-abundance native peptides using a single drop of human plasma. To discover a novel polypeptide that potently modulates the cardiovascular system, we performed a bioinformatics analysis of the large-scale identification results, sequentially synthesized the selected peptide sequences, tested their biological activities, and identified a 30-amino-acid proatherogenic peptide, GIP_HUMAN[22-51], as a potent proatherosclerotic peptide hormone. GIP_HUMAN[22-51] has a common precursor with the glucose-dependent insulinotropic polypeptide (GIP) and is located immediately N-terminal to GIP. Chronic infusion of GIP_HUMAN[22-51] into ApoE-/- mice accelerated the development of aortic atherosclerotic lesions, which were inhibited by co-infusions with an anti-GIP_HUMAN[22-51] antibody. GIP_HUMAN[22-51] increased the serum concentrations of many inflammatory and proatherogenic proteins, whereas neutralising antibodies reduced their levels. GIP_HUMAN[22-51] induced IκB-α degradation and nuclear translocation of NF-κB in human vascular endothelial cells and macrophages. Immunoreactive GIP_HUMAN[22-51] was detected in human tissues but there was no colocalization with the GIP. The plasma GIP_HUMAN[22-51] concentration in healthy humans determined using a stable-isotope tagged peptide was approximately 0.6 nM. This study discovered a novel endogenous proatherogenic peptide by using a human plasma native peptidomic resource.
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Affiliation(s)
- Tsuguto Masaki
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Yoshio Kodera
- Department of Physics, Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Michishige Terasaki
- Division of Diabetes, Metabolism and Endocrinology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Kazumi Fujimoto
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
- Department of Physics, Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Tsutomu Hirano
- Division of Diabetes, Metabolism and Endocrinology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Masayoshi Shichiri
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan.
- Tokyo Kyosai Hospital, 2-3-8 Nakameguro, Meguro-ku, Tokyo, 153-8934, Japan.
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15
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Correa‐da‐Silva F, Fliers E, Swaab DF, Yi C. Hypothalamic neuropeptides and neurocircuitries in Prader Willi syndrome. J Neuroendocrinol 2021; 33:e12994. [PMID: 34156126 PMCID: PMC8365683 DOI: 10.1111/jne.12994] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/19/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
Prader-Willi Syndrome (PWS) is a rare and incurable congenital neurodevelopmental disorder, resulting from the absence of expression of a group of genes on the paternally acquired chromosome 15q11-q13. Phenotypical characteristics of PWS include infantile hypotonia, short stature, incomplete pubertal development, hyperphagia and morbid obesity. Hypothalamic dysfunction in controlling body weight and food intake is a hallmark of PWS. Neuroimaging studies have demonstrated that PWS subjects have abnormal neurocircuitry engaged in the hedonic and physiological control of feeding behavior. This is translated into diminished production of hypothalamic effector peptides which are responsible for the coordination of energy homeostasis and satiety. So far, studies with animal models for PWS and with human post-mortem hypothalamic specimens demonstrated changes particularly in the infundibular and the paraventricular nuclei of the hypothalamus, both in orexigenic and anorexigenic neural populations. Moreover, many PWS patients have a severe endocrine dysfunction, e.g. central hypogonadism and/or growth hormone deficiency, which may contribute to the development of increased fat mass, especially if left untreated. Additionally, the role of non-neuronal cells, such as astrocytes and microglia in the hypothalamic dysregulation in PWS is yet to be determined. Notably, microglial activation is persistently present in non-genetic obesity. To what extent microglia, and other glial cells, are affected in PWS is poorly understood. The elucidation of the hypothalamic dysfunction in PWS could prove to be a key feature of rational therapeutic management in this syndrome. This review aims to examine the evidence for hypothalamic dysfunction, both at the neuropeptidergic and circuitry levels, and its correlation with the pathophysiology of PWS.
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Affiliation(s)
- Felipe Correa‐da‐Silva
- Department of Endocrinology and MetabolismAmsterdam Gastroenterology Endocrinology and MetabolismAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Laboratory of EndocrinologyAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Department of Neuropsychiatric DisordersNetherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Eric Fliers
- Department of Endocrinology and MetabolismAmsterdam Gastroenterology Endocrinology and MetabolismAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
| | - Dick F. Swaab
- Department of Neuropsychiatric DisordersNetherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Chun‐Xia Yi
- Department of Endocrinology and MetabolismAmsterdam Gastroenterology Endocrinology and MetabolismAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Laboratory of EndocrinologyAmsterdam University Medical Center (UMC)University of AmsterdamAmsterdamThe Netherlands
- Department of Neuropsychiatric DisordersNetherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
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16
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Takeda Y, Fujita Y, Yanagimachi T, Maruyama N, Bessho R, Sakagami H, Honjo J, Yokoyama H, Haneda M. Establishment of novel specific assay for short-form glucose-dependent insulinotropic polypeptide and evaluation of its secretion in nondiabetic subjects. Physiol Rep 2021; 8:e14469. [PMID: 32472669 PMCID: PMC7260394 DOI: 10.14814/phy2.14469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/25/2022] Open
Abstract
The short‐form glucose‐dependent insulinotropic polypeptide (GIP) (1–30) is released from islet alpha cells and promotes insulin secretion in a paracrine manner in vitro. However, it is not well elucidated how GIP (1–30) is involved in glucose metabolism in vivo, since a specific assay system for GIP (1–30) has not yet been established. We first developed a sandwich enzyme‐linked immunosorbent assay (ELISA) specific for GIP (1–30) by combining a novel antibody specific to the GIP (1–30) C terminus with the common antibody against GIP N terminus. Then, we explored cross‐reactivities with incretins and glucagon‐related peptides in this ELISA. GIP (1–30) amide, but not GIP (1–42), GLP‐1, or glucagon increased absorbance in a dose‐dependent manner. We next measured plasma GIP (1–30) concentrations in nondiabetic participants (ND) during a 75‐g oral glucose tolerance test or cookie meal test (carbohydrates 75 g, lipids 28.5 g, proteins 8.5 g). Both glucose and cookie load increased GIP (1–30) concentrations in ND, but the increases were much lower than those of GIP (1–42). Furthermore, the DPP‐4 inhibitor significantly increased GIP (1–30) concentrations similarly to GIP (1–42) in ND. In conclusion, we for the first time developed an ELISA specific for GIP (1–30) and revealed its secretion in ND.
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Affiliation(s)
- Yasutaka Takeda
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Yukihiro Fujita
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan.,Division of Diabetology, Endocrinology and Nephrology, Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Tsuyoshi Yanagimachi
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan.,Division of Diabetology, Endocrinology and Nephrology, Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan
| | | | - Ryoichi Bessho
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Hidemitsu Sakagami
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Jun Honjo
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
| | | | - Masakazu Haneda
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
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17
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Abstract
The kexin-like proprotein convertases perform the initial proteolytic cleavages that ultimately generate a variety of different mature peptide and proteins, ranging from brain neuropeptides to endocrine peptide hormones, to structural proteins, among others. In this review, we present a general introduction to proprotein convertase structure and biochemistry, followed by a comprehensive discussion of each member of the kexin-like subfamily of proprotein convertases. We summarize current knowledge of human proprotein convertase insufficiency syndromes, including genome-wide analyses of convertase polymorphisms, and compare these to convertase null and mutant mouse models. These mouse models have illuminated our understanding of the roles specific convertases play in human disease and have led to the identification of convertase-specific substrates; for example, the identification of procorin as a specific PACE4 substrate in the heart. We also discuss the limitations of mouse null models in interpreting human disease, such as differential precursor cleavage due to species-specific sequence differences, and the challenges presented by functional redundancy among convertases in attempting to assign specific cleavages and/or physiological roles. However, in most cases, knockout mouse models have added substantively both to our knowledge of diseases caused by human proprotein convertase insufficiency and to our appreciation of their normal physiological roles, as clearly seen in the case of the furin, proprotein convertase 1/3, and proprotein convertase 5/6 mouse models. The creation of more sophisticated mouse models with tissue- or temporally-restricted expression of specific convertases will improve our understanding of human proprotein convertase insufficiency and potentially provide support for the emerging concept of therapeutic inhibition of convertases.
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Affiliation(s)
- Manita Shakya
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
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18
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Novel Homozygous Inactivating Mutation in the PCSK1 Gene in an Infant with Congenital Malabsorptive Diarrhea. Genes (Basel) 2021; 12:genes12050710. [PMID: 34068683 PMCID: PMC8151971 DOI: 10.3390/genes12050710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/02/2021] [Accepted: 05/07/2021] [Indexed: 01/03/2023] Open
Abstract
Proprotein convertase 1/3 (PC1/3), encoded by the PCSK1 gene, is expressed in neuronal and (entero)endocrine cell types, where it cleaves and hence activates a number of protein precursors that play a key role in energy homeostasis. Loss-of-function mutations in PCSK1 cause a recessive complex endocrinopathy characterized by malabsorptive diarrhea and early-onset obesity. Despite the fact that neonatal malabsorptive diarrhea is observed in all patients, it has remained understudied. The aim of this study was to investigate the enteroendocrine pathologies in a male patient with congenital PCSK1 deficiency carrying the novel homozygous c.1034A>C (p.E345A) mutation. This patient developed malabsorptive diarrhea and metabolic acidosis within the first week of life, but rapid weight gain was observed after total parenteral nutrition, and he displayed high proinsulin levels and low adrenocorticotropin. In vitro analysis showed that the p.E345A mutation in PC1/3 resulted in a (near) normal autocatalytic proPC1/3 processing and only partially impaired PC1/3 secretion, but the processing of a substrate in trans was completely blocked. Immunohistochemical staining did not reveal changes in the proGIP/GIP and proglucagon/GLP-1 ratio in colonic tissue. Hence, we report a novel PCSK1 deficient patient who, despite neonatal malabsorptive diarrhea, showed a normal morphology in the small intestine.
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19
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Boer GA, Hartmann B, Holst JJ. Pharmacokinetics of exogenous GIP(1-42) in C57Bl/6 mice; Extremely rapid degradation but marked variation between available assays. Peptides 2021; 136:170457. [PMID: 33245951 PMCID: PMC7883216 DOI: 10.1016/j.peptides.2020.170457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022]
Abstract
Like other peptide hormones, glucose-dependent insulinotropic polypeptide (GIP) is rapidly cleared from the circulation. Dipeptidyl peptidase-4 (DPP-4) is known to be involved. Information on the overall pharmacokinetics of GIP in rodents is, however, lacking. We investigated the pharmacokinetics of exogenous GIP after intravenous, subcutaneous and intraperitoneal injection with and without DPP-4 inhibition in conscious female C57Bl/6 mice. Secondly, we compared total and intact GIP levels measured by an in-house RIA and commercially available ELISA kits to determine the suitability of these methods for in vivo and in vitro measurements. GIP half-life following intravenous injection amounted to 93 ± 2 s, which was extended to 5 ± 0.6 min by inhibition of DPP-4. Intact GIP levels following subcutaneous and intraperitoneal GIP administration were approximately 15 % of total GIP. The area under the curve of intact GIP (GIP exposure) following GIP injection was significantly increased by DPP-4 inhibition, whereas total GIP levels remained unchanged. We found significant variation between measurements of total, but not intact GIP performed with our in-house RIA and ELISAs in samples obtained after in vivo administration of GIP. Different preanalytical sample preparation (EDTA plasma, heparin plasma, assay buffer and PBS) significantly influenced results for all ELISA kits used. Thus, in experiments involving exogenous GIP(1-42) administration in mice, it is important to consider that this will result in a very low ratio of intact:total peptide but co-administration of a DPP-4 inhibitor greatly elevates this ratio. Furthermore, for comparison of GIP levels, it is essential to maintain uniformity concerning assay methodology and sample preparation.
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Affiliation(s)
- Geke Aline Boer
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Bolette Hartmann
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Jens Juul Holst
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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20
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Boer GA, Holst JJ. Incretin Hormones and Type 2 Diabetes-Mechanistic Insights and Therapeutic Approaches. BIOLOGY 2020; 9:biology9120473. [PMID: 33339298 PMCID: PMC7766765 DOI: 10.3390/biology9120473] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023]
Abstract
Simple Summary When we ingest a meal, our intestine secretes hormones that are released into the bloodstream. Amongst these hormones are the incretins hormones which stimulate the release of insulin from the pancreas which is essential for the regulation of in particular postprandial glucose concentrations. In patients with type 2 diabetes, the effect of the incretins is diminished. This is thought to contribute importantly to the pathophysiology of the disease. However, in pharmacological amounts, the incretins may still influence insulin secretion and metabolism. Much research has therefore been devoted to the development of incretin-based therapies for type 2 diabetes. These therapies include compounds that strongly resemble the incretins, hereby stimulating their effects as well as inhibitors of the enzymatic degradation of the hormones, thereby increasing the concentration of incretins in the blood. Both therapeutic approaches have been implemented successfully, but research is still ongoing aimed at the development of further optimized therapies. Abstract Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from the gut upon nutrient stimulation and regulate postprandial metabolism. These hormones are known as classical incretin hormones and are responsible for a major part of postprandial insulin release. The incretin effect is severely reduced in patients with type 2 diabetes, but it was discovered that administration of GLP-1 agonists was capable of normalizing glucose control in these patients. Over the last decades, much research has been focused on the development of incretin-based therapies for type 2 diabetes. These therapies include incretin receptor agonists and inhibitors of the incretin-degrading enzyme dipeptidyl peptidase-4. Especially the development of diverse GLP-1 receptor agonists has shown immense success, whereas studies of GIP monotherapy in patients with type 2 diabetes have consistently been disappointing. Interestingly, both GIP-GLP-1 co-agonists and GIP receptor antagonists administered in combination with GLP-1R agonists appear to be efficient with respect to both weight loss and control of diabetes, although the molecular mechanisms behind these effects remain unknown. This review describes our current knowledge of the two incretin hormones and the development of incretin-based therapies for treatment of type 2 diabetes.
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Affiliation(s)
- Geke Aline Boer
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark;
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark;
- NNF Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
- Correspondence: ; Tel.: +45-2875-7518
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21
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Alayi T, Tawalbeh SM, Ogundele M, Smith HR, Samsel AM, Barbieri ML, Hathout Y. Tandem Mass Tag-Based Serum Proteome Profiling for Biomarker Discovery in Young Duchenne Muscular Dystrophy Boys. ACS OMEGA 2020; 5:26504-26517. [PMID: 33110978 PMCID: PMC7581259 DOI: 10.1021/acsomega.0c03206] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Blood-accessible molecular biomarkers are becoming highly attractive tools to assess disease progression and response to therapies in Duchenne muscular dystrophy (DMD) especially in very young patients for whom other outcome measures remain subjective and challenging. In this study, we have standardized a highly specific and reproducible multiplexing mass spectrometry method using the tandem mass tag (TMT) strategy in combination with depletion of abundant proteins from serum and high-pH reversed-phase peptide fractionation. Differential proteome profiling of 4 year-old DMD boys (n = 9) and age-matched healthy controls (n = 9) identified 38 elevated and 50 decreased serum proteins (adjusted P < 0.05, FDR <0.05) in the DMD group relative to the healthy control group. As expected, we confirmed previously reported biomarkers but also identified novel biomarkers. These included novel muscle injury-associated biomarkers such as telethonin, smoothelin-like protein 1, cofilin-1, and plectin, additional muscle-specific enzymes such as UTP-glucose-1-phosphate uridylyltransferase, aspartate aminotransferase, pyruvate kinase PKM, lactotransferrin, tissue alpha-l-fucosidase, pantetheinase, and ficolin-1, and some pro-inflammatory and cell adhesion-associated biomarkers such as leukosialin, macrophage receptor MARCO, vitronectin, galectin-3-binding protein, and ProSAAS. The workflow including serum depletion, sample processing, and mass spectrometry analysis was found to be reproducible and stable over time with CV < 20%. Furthermore, the method was found to be superior in terms of specificity compared to other multiplexing affinity-based methods. These findings demonstrate the specificity and reliability of TMT-based mass spectrometry methods in detection and identification of serum biomarkers in presymptomatic young DMD patients.
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Affiliation(s)
- Tchilabalo
D. Alayi
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
| | - Shefa M. Tawalbeh
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
- Department
of Biomedical Engineering, Binghamton University−SUNY, 4400 Vestal Pkwy E, Binghamton, New York 13902, United States
| | - Michael Ogundele
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
- Department
of Biomedical Engineering, Binghamton University−SUNY, 4400 Vestal Pkwy E, Binghamton, New York 13902, United States
| | - Holly R. Smith
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
- Department
of Biochemistry, Binghamton University−SUNY, 4400 Vestal Pkwy E, Binghamton, New York 13902, United States
| | - Alison M. Samsel
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
| | - Marissa L. Barbieri
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
| | - Yetrib Hathout
- Department
of Pharmaceutical Science, School of Pharmacy and Pharmaceutical Sciences, Binghamton University−SUNY, Johnson City, New York 13790, United States
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22
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Lynggaard MB, Gasbjerg LS, Christensen MB, Knop FK. GIP(3-30)NH 2 - a tool for the study of GIP physiology. Curr Opin Pharmacol 2020; 55:31-40. [PMID: 33053504 DOI: 10.1016/j.coph.2020.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/12/2020] [Accepted: 08/25/2020] [Indexed: 12/25/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gut hormone impacting glucose, lipid and bone metabolism through the GIP receptor (GIPR). The GIP system has key species differences complicating the translation of findings from rodent to human physiology. Furthermore, the effects of endogenous GIP in humans have been difficult to tease out due to the lack of a suitable GIPR antagonist. The naturally occurring GIP(3-30)NH2 has turned out to constitute a safe and efficacious GIPR antagonist for rodent and human use. To study GIP physiology, it is recommended to use the species-specific GIP(3-30)NH2 peptide sequence, and for human intravenous infusions, an antagonist:agonist ratio of a minimum of 600 with a 20min infusion time before the intervention of interest is recommended. Several studies using GIP(3-30)NH2 are coming, hopefully providing new insights into the physiology of GIP, the pathophysiologic involvement of GIP in several diseases and the therapeutic potential of the GIPR.
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Affiliation(s)
- Mads Bank Lynggaard
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Lærke Smidt Gasbjerg
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel Bring Christensen
- Center for Clinical Metabolic 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
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 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.
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23
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Deacon CF. Metabolism of GIP and the contribution of GIP to the glucose-lowering properties of DPP-4 inhibitors. Peptides 2020; 125:170196. [PMID: 31706956 DOI: 10.1016/j.peptides.2019.170196] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 01/26/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone with insulinotropic and glucagonotropic actions, and is believed to be the more physiologically important incretin hormone in healthy humans. Together with the other incretin hormone, glucagon-like peptide-1 (GLP-1), it plays an important role in regulating glucose homeostasis. Both GLP-1 and GIP are substrates of the enzyme dipeptidyl peptidase-4 (DPP-4), and DPP-4 inhibitors, which potentiate their effects on glycaemic control, are now used to treat type 2 diabetes (T2D). This review describes how post-translational processing of the GIP precursor molecule and post-release degradation of the secretory products give rise to multiple isoforms of GIP, some, but not all of which are biologically active, and discusses how this impacts upon their measurement by immunological- and bioassay-based methods. DPP-4 inhibitors reduce degradation of GIP, and although the insulinotropic effects of GIP are impaired in patients with T2D, they can be at least partially restored if glycaemic control is improved. Therefore, given that studies with incretin receptor antagonists indicate that not all of the glucose-lowering effects of DPP-4 inhibition can be accounted for by GLP-1 alone, evidence supports the notion that GIP may play a role in mediating the anti-hyperglycaemic effects of DPP-4 inhibition, while its glucagonotropic actions at lower glucose levels may contribute to the low risk of hypoglycaemia associated with DPP-4 inhibitors.
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Affiliation(s)
- Carolyn F Deacon
- Department of Biomedical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
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24
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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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25
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Yanagimachi T, Fujita Y, Takeda Y, Honjo J, Yokoyama H, Haneda M. Receptor-Mediated Bioassay Reflects Dynamic Change of Glucose-Dependent Insulinotropic Polypeptide by Dipeptidyl Peptidase 4 Inhibitor Treatment in Subjects With Type 2 Diabetes. Front Endocrinol (Lausanne) 2020; 11:214. [PMID: 32390941 PMCID: PMC7193081 DOI: 10.3389/fendo.2020.00214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/25/2020] [Indexed: 11/15/2022] Open
Abstract
Objective: We recently observed a greater increase in plasma levels of bioactive glucose-dependent insulinotropic polypeptide (GIP) than glucagon-like peptide 1 (GLP-1) using the receptor-mediated bioassays in the subjects with normal glycemic tolerance (NGT) treated with dipeptidyl peptidase 4 (DPP-4) inhibitors, which may be unappreciated using conventional enzyme-linked immunosorbent assays (ELISAs) during oral glucose tolerance test. Thus, we determined incretin levels in addition to glucagon level using the bioassays in type 2 diabetes mellitus (T2DM) subjects with or without treatment of DPP-4 inhibitor, to evaluate whether these assays can accurately measure bioactivity of these peptides. Methods: We performed single meal tolerance test (MTT) by using a cookie meal (carbohydrate 75.0 g, protein 8.0 g, fat 28.5 g) in the subjects with NGT (n = 9), the subjects with T2DM treated without DPP-4 inhibitor (n = 7) and the subjects with T2DM treated with DPP-4 inhibitor (n = 10). All subjects fasted for 10-12 h before the MTT, and blood samples were collected at 0, 30, 60, and 120 min. We used the cell lines stably cotransfected with human-form GIP, GLP-1 or glucagon receptor, and a cyclic adenosine monophosphate-inducible luciferase expression construct for the bioassays. We measured active GIP, active GLP-1, and glucagon by the bioassays. To evaluate the efficacy of bioassay, we measured identical samples via ELISA kits. Results: During the single MTT study, postprandial active GIP bioassay levels of T2DM with DPP-4 inhibitor treatment were drastically higher than those of NGT and T2DM without DPP-4 inhibitor, although the DPP-4 inhibitor-treated group showed moderate increase of active GIPELISA and active GLP-1 bioassay , while active GLP-1 bioassay levels of T2DM subjects without DPP-4 inhibitor were comparable to those of NGT subjects. During the serial MTT, administration of DPP-4 inhibitor significantly increased active GIP bioassay levels, but not active GLP-1 bioassay . Conclusions: In comparison to conventional ELISA, receptor-mediated bioassay reflects dynamic change of GIP polypeptide by DPP-4 inhibitor treatment in subjects with type 2 diabetes.
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Affiliation(s)
- Tsuyoshi Yanagimachi
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Yukihiro Fujita
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
- Department of Diabetology, Endocrinology and Nephrology, Department of Internal Medicine, Shiga University of Medical Science, Otsu, Japan
- *Correspondence: Yukihiro Fujita
| | - Yasutaka Takeda
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Jun Honjo
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
- Jiyugaoka Medical Clinic, Internal Medicine, Obihiro, Japan
| | | | - Masakazu Haneda
- Division of Metabolism and Biosystemic Science, Department of Internal Medicine, Asahikawa Medical University, Asahikawa, Japan
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26
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Holst JJ, Albrechtsen NJW, Rosenkilde MM, Deacon CF. Physiology of the Incretin Hormones,
GIP
and
GLP
‐1—Regulation of Release and Posttranslational Modifications. Compr Physiol 2019; 9:1339-1381. [DOI: 10.1002/cphy.c180013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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27
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Khoonsari PE, Musunri S, Herman S, Svensson CI, Tanum L, Gordh T, Kultima K. Systematic analysis of the cerebrospinal fluid proteome of fibromyalgia patients. J Proteomics 2019; 190:35-43. [DOI: 10.1016/j.jprot.2018.04.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 01/08/2023]
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28
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Optimization of peptide-based polyagonists for treatment of diabetes and obesity. Bioorg Med Chem 2018; 26:2873-2881. [DOI: 10.1016/j.bmc.2017.10.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 10/31/2017] [Indexed: 12/28/2022]
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29
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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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30
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Jones B, Bloom SR, Buenaventura T, Tomas A, Rutter GA. Control of insulin secretion by GLP-1. Peptides 2018; 100:75-84. [PMID: 29412835 DOI: 10.1016/j.peptides.2017.12.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 12/12/2022]
Abstract
Stimulation of insulin secretion by glucagon-like peptide-1 (GLP-1) and other gut-derived peptides is central to the incretin response to ingesting nutriments. Analogues of GLP-1, and inhibitors of its breakdown, have found widespread clinical use for the treatment of type 2 diabetes (T2D) and obesity. The release of these peptides underlies the improvements in glycaemic control and disease remission after bariatric surgery. Given therapeutically, GLP-1 analogues can lead to side effects including nausea, which limit dosage. Greater understanding of the interactions between the GLP-1 receptor (GLP-1R) and both the endogenous and artificial ligands therefore holds promise to provide more efficacious compounds. Here, we discuss recent findings concerning the signalling and trafficking of the GLP-1R in pancreatic beta cells. Leveraging "bias" at the receptor towards cAMP generation versus the recruitment of β-arrestins and extracellular signal-regulated kinases (ERK1/2) activation may allow the development of new analogues with significantly improved clinical efficacy. We describe how, unexpectedly, relatively low-affinity agonists, which prompt less receptor internalisation than the parent compound, provoke greater insulin secretion and consequent improvements in glycaemia.
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Affiliation(s)
- Ben Jones
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Stephen R Bloom
- Section of Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Teresa Buenaventura
- Section of Cell Biology and Functional Genomics & Imperial Consortium for Islet Biology and Diabetes, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics & Imperial Consortium for Islet Biology and Diabetes, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics & Imperial Consortium for Islet Biology and Diabetes, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK.
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31
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Brandt SJ, Götz A, Tschöp MH, Müller TD. Gut hormone polyagonists for the treatment of type 2 diabetes. Peptides 2018; 100:190-201. [PMID: 29412819 PMCID: PMC5805859 DOI: 10.1016/j.peptides.2017.12.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 12/20/2022]
Abstract
Chemical derivatives of the gut-derived peptide hormone glucagon-like peptide 1 (GLP-1) are among the best-in-class pharmacotherapies to treat obesity and type 2 diabetes. However, GLP-1 analogs have modest weight lowering capacity, in the range of 5-10%, and the therapeutic window is hampered by dose-dependent side effects. Over the last few years, a new concept has emerged: combining the beneficial effects of several key metabolic hormones into a single molecular entity. Several unimolecular GLP-1-based polyagonists have shown superior metabolic action compared to GLP-1 monotherapies. In this review article, we highlight the history of polyagonists targeting the receptors for GLP-1, GIP and glucagon, and discuss recent progress in expanding of this concept to now allow targeted delivery of nuclear hormones via GLP-1 and other gut hormones, as a novel approach towards more personalized pharmacotherapies.
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Affiliation(s)
- Sara J Brandt
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany
| | - Anna Götz
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; Department of Internal Medicine I, University Hospital RWTH Aachen, Aachen, Germany; Institute for Diabetes und Regeneration, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748, Garching, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
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32
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Gasbjerg LS, Christensen MB, Hartmann B, Lanng AR, Sparre-Ulrich AH, Gabe MBN, Dela F, Vilsbøll T, Holst JJ, Rosenkilde MM, Knop FK. GIP(3-30)NH 2 is an efficacious GIP receptor antagonist in humans: a randomised, double-blinded, placebo-controlled, crossover study. Diabetologia 2018; 61:413-423. [PMID: 28948296 DOI: 10.1007/s00125-017-4447-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone secreted postprandially from enteroendocrine K cells, but despite therapeutically interesting effects, GIP physiology in humans remains incompletely understood. Progress in this field could be facilitated by a suitable GIP receptor antagonist. For the first time in humans, we investigated the antagonistic properties of the naturally occurring GIP(3-30)NH2 in in vivo and in in vitro receptor studies. METHODS In transiently transfected COS-7 cells, GIP(3-30)NH2 was evaluated with homologous receptor binding and receptor activation (cAMP accumulation) studies at the glucagon-like peptide 1 (GLP-1), glucagon-like peptide-2 (GLP-2), glucagon, secretin and growth hormone-releasing hormone (GHRH) receptors. Ten healthy men (eligibility criteria: age 20-30 years, HbA1c less than 6.5% [48 mmol/mol] and fasting plasma glucose [FPG] less than 7 mmol/l) were included in the clinical study. Data were collected as plasma and serum samples from a cubital vein cannula. As primary outcome, insulin secretion and glucose requirements were evaluated together with in a randomised, four-period, crossover design by infusing GIP(3-30)NH2 (800 pmol kg-1 min-1), GIP (1.5 pmol kg-1 min-1), a combination of these or placebo during hyperglycaemic clamp experiments. The content of the infusions were blinded to the study participants and experimental personnel. No study participants dropped out. RESULTS GIP(3-30)NH2 neither bound, stimulated nor antagonised a series of related receptors in vitro. The elimination plasma half-life of GIP(3-30)NH2 in humans was 7.6 ± 1.4 min. Markedly larger amounts of glucose were required to maintain the clamp during GIP infusion compared with the other days. GIP-induced insulin secretion was reduced by 82% (p < 0.0001) during co-infusion with GIP(3-30)NH2, and the need for glucose was reduced to placebo levels. There were no effects of GIP(3-30)NH2 alone or of GIP with or without GIP(3-30)NH2 on plasma glucagon, GLP-1, somatostatin, triacylglycerols, cholesterol, glycerol or NEFA. GIP(3-30)NH2 administration was well tolerated and without side effects. CONCLUSIONS/INTERPRETATION We conclude that GIP(3-30)NH2 is an efficacious and specific GIP receptor antagonist in humans suitable for studies of GIP physiology and pathophysiology. TRIAL REGISTRATION ClinicalTrials.gov registration no. NCT02747472. FUNDING The study was funded by Gangstedfonden, the European Foundation for the Study of Diabetes, and Aase og Ejnar Danielsens fond.
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Affiliation(s)
- Lærke S Gasbjerg
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, 2900, Hellerup, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel B Christensen
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, 2900, 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
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Amalie R Lanng
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, 2900, Hellerup, Denmark
| | - Alexander H Sparre-Ulrich
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maria B N Gabe
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Dela
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Geriatrics, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, 2900, Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, University of Copenhagen, Gentofte, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, 2900, Hellerup, Denmark.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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33
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Khan D, Moffet CR, Flatt PR, Kelly C. Role of islet peptides in beta cell regulation and type 2 diabetes therapy. Peptides 2018; 100:212-218. [PMID: 29412821 DOI: 10.1016/j.peptides.2017.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/22/2017] [Indexed: 12/25/2022]
Abstract
The endocrine pancreas is composed of islets of Langerhans, which secrete a variety of peptide hormones critical for the maintenance of glucose homeostasis. Insulin is the primary regulator of glucose and its secretion from beta-cells is tightly regulated in response to physiological demands. Direct cell-cell communication within islets is essential for glucose-induced insulin secretion. Emerging data suggest that islet connectivity is also important in the regulating the release of other islet hormones including glucagon and somatostatin. Autocrine and paracrine signals exerted by secreted peptides within the islet also play a key role. A great deal of attention has focused on classical islet peptides, namely insulin, glucagon and somatostatin. Recently, it has become clear that islets also synthesise and secrete a range of non-classical peptides, which regulate beta-cell function and insulin release. The current review summarises the roles of islet cell connectivity and islet peptide-driven autocrine and paracrine signalling in beta-cell function and survival. The potential to harness the paracrine effects of non-classical islet peptides for the treatment of type 2 diabetes is also briefly discussed.
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Affiliation(s)
- Dawood Khan
- Northern Ireland Centre for Stratified Medicine, Biomedical Sciences Research Institute, University of Ulster, C-TRIC Building, Altnagelvin Area Hospital, Glenshane Road, L/Derry, BT47 6SB, Northern Ireland, UK
| | - Charlotte R Moffet
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Catriona Kelly
- Northern Ireland Centre for Stratified Medicine, Biomedical Sciences Research Institute, University of Ulster, C-TRIC Building, Altnagelvin Area Hospital, Glenshane Road, L/Derry, BT47 6SB, Northern Ireland, UK.
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Jorsal T, Rhee NA, Pedersen J, Wahlgren CD, Mortensen B, Jepsen SL, Jelsing J, Dalbøge LS, Vilmann P, Hassan H, Hendel JW, Poulsen SS, Holst JJ, Vilsbøll T, Knop FK. Enteroendocrine K and L cells in healthy and type 2 diabetic individuals. Diabetologia 2018; 61:284-294. [PMID: 28956082 DOI: 10.1007/s00125-017-4450-9] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 08/14/2017] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Enteroendocrine K and L cells are pivotal in regulating appetite and glucose homeostasis. Knowledge of their distribution in humans is sparse and it is unknown whether alterations occur in type 2 diabetes. We aimed to evaluate the distribution of enteroendocrine K and L cells and relevant prohormone-processing enzymes (using immunohistochemical staining), and to evaluate the mRNA expression of the corresponding genes along the entire intestinal tract in individuals with type 2 diabetes and healthy participants. METHODS In this cross-sectional study, 12 individuals with type 2 diabetes and 12 age- and BMI-matched healthy individuals underwent upper and lower double-balloon enteroscopy with mucosal biopsy retrieval from approximately every 30 cm of the small intestine and from seven specific anatomical locations in the large intestine. RESULTS Significantly different densities for cells positive for chromogranin A (CgA), glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide, peptide YY, prohormone convertase (PC) 1/3 and PC2 were observed along the intestinal tract. The expression of CHGA did not vary along the intestinal tract, but the mRNA expression of GCG, GIP, PYY, PCSK1 and PCSK2 differed along the intestinal tract. Lower counts of CgA-positive and PC1/3-positive cells, respectively, were observed in the small intestine of individuals with type 2 diabetes compared with healthy participants. In individuals with type 2 diabetes compared with healthy participants, the expression of GCG and PYY was greater in the colon, while the expression of GIP and PCSK1 was greater in the small intestine and colon, and the expression of PCSK2 was greater in the small intestine. CONCLUSIONS/INTERPRETATION Our findings provide a detailed description of the distribution of enteroendocrine K and L cells and the expression of their products in the human intestinal tract and demonstrate significant differences between individuals with type 2 diabetes and healthy participants. TRIAL REGISTRATION NCT03044860.
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Affiliation(s)
- Tina Jorsal
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, DK-2900, Hellerup, Denmark
| | - Nicolai A Rhee
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, DK-2900, Hellerup, Denmark
- Novo Nordisk A/S, Bagsværd, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Camilla D Wahlgren
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, DK-2900, Hellerup, Denmark
| | - Brynjulf Mortensen
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, DK-2900, Hellerup, Denmark
- Chr. Hansen A/S, Hørsholm, Denmark
| | - Sara L Jepsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Louise S Dalbøge
- Gubra ApS, Hørsholm, Denmark
- Novo Nordisk Research Center, Seattle, WA, USA
| | - Peter Vilmann
- Endoscopic Unit, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Gastrounit, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Hazem Hassan
- Endoscopic Unit, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Gastrounit, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Jakob W Hendel
- Endoscopic Unit, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Gastrounit, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - Steen S Poulsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, DK-2900, Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, University of Copenhagen, Gentofte, Denmark
| | - Filip K Knop
- Center for Diabetes Research, Gentofte Hospital, University of Copenhagen, Kildegårdsvej 28, DK-2900, Hellerup, Denmark.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Vieira A, Druelle N, Avolio F, Napolitano T, Navarro-Sanz S, Silvano S, Collombat P. β-Cell Replacement Strategies: The Increasing Need for a "β-Cell Dogma". Front Genet 2017. [PMID: 28634486 PMCID: PMC5459879 DOI: 10.3389/fgene.2017.00075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Type 1 diabetes is an auto-immune disease resulting in the loss of pancreatic β-cells and, consequently, in chronic hyperglycemia. Insulin supplementation allows diabetic patients to control their glycaemia quite efficiently, but treated patients still display an overall shortened life expectancy and an altered quality of life as compared to their healthy counterparts. In this context and due to the ever increasing number of diabetics, establishing alternative therapies has become a crucial research goal. Most current efforts therefore aim at generating fully functional insulin-secreting β-like cells using multiple approaches. In this review, we screened the literature published since 2011 and inventoried the selected markers used to characterize insulin-secreting cells generated by in vitro differentiation of stem/precursor cells or by means of in vivo transdifferentiation. By listing these features, we noted important discrepancies when comparing the different approaches for the initial characterization of insulin-producing cells as true β-cells. Considering the recent advances achieved in this field of research, the necessity to establish strict guidelines has become a subject of crucial importance, especially should one contemplate the next step, which is the transplantation of in vitro or ex vivo generated insulin-secreting cells in type 1 diabetic patients.
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Affiliation(s)
- Andhira Vieira
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
| | - Noémie Druelle
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
| | - Fabio Avolio
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
| | - Tiziana Napolitano
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
| | - Sergi Navarro-Sanz
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
| | - Serena Silvano
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
| | - Patrick Collombat
- Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, iBV, Université Côte d'AzurNice, France
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Sparre-Ulrich A, Gabe M, Gasbjerg L, Christiansen C, Svendsen B, Hartmann B, Holst J, Rosenkilde M. GIP(3–30)NH2 is a potent competitive antagonist of the GIP receptor and effectively inhibits GIP-mediated insulin, glucagon, and somatostatin release. Biochem Pharmacol 2017; 131:78-88. [DOI: 10.1016/j.bcp.2017.02.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/14/2017] [Indexed: 12/31/2022]
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Mabilleau G. Interplay between bone and incretin hormones: A review. Morphologie 2017; 101:9-18. [PMID: 27423214 DOI: 10.1016/j.morpho.2016.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 06/06/2023]
Abstract
Bone is a tissue with multiple functions that is built from the molecular to anatomical levels to resist and adapt to mechanical strains. Among all the factors that might control the bone organization, a role for several gut hormones called "incretins" has been suspected. The present review summarizes the current evidences on the effects of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) in bone physiology.
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Affiliation(s)
- G Mabilleau
- GEROM-LHEA, groupe d'études remodelage osseux et biomatériaux, institut de biologie en santé, université d'Angers, 4, rue Larrey, 49933 Angers cedex 09, France; SCIAM, institut de biologie en santé, université d'Angers, 4, rue Larrey, 49933 Angers cedex 09, France.
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38
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Pujadas G, Drucker DJ. Vascular Biology of Glucagon Receptor Superfamily Peptides: Mechanistic and Clinical Relevance. Endocr Rev 2016; 37:554-583. [PMID: 27732058 DOI: 10.1210/er.2016-1078] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Regulatory peptides produced in islet and gut endocrine cells, including glucagon, glucagon-like peptide-1 (GLP-1), GLP-2, and glucose-dependent insulinotropic polypeptide, exert actions with considerable metabolic importance and translational relevance. Although the clinical development of GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors has fostered research into how these hormones act on the normal and diseased heart, less is known about the actions of these peptides on blood vessels. Here we review the effects of these peptide hormones on normal blood vessels and highlight their vascular actions in the setting of experimental and clinical vascular injury. The cellular localization and signal transduction properties of the receptors for glucagon, GLP-1, GLP-2, and glucose-dependent insulinotropic polypeptide are discussed, with emphasis on endothelial cells and vascular smooth muscle cells. The actions of these peptides on the control of blood flow, blood pressure, angiogenesis, atherosclerosis, and vascular inflammation are reviewed with a focus on elucidating direct and indirect mechanisms of action. How these peptides traverse the blood-brain barrier is highlighted, with relevance to the use of GLP-1 receptor agonists to treat obesity and neurodegenerative disorders. Wherever possible, we compare actions identified in cell lines and primary cell culture with data from preclinical studies and, when available, results of human investigation, including studies in subjects with diabetes, obesity, and cardiovascular disease. Throughout the review, we discuss pitfalls, limitations, and challenges of the existing literature and highlight areas of controversy and uncertainty. The increasing use of peptide-based therapies for the treatment of diabetes and obesity underscores the importance of understanding the vascular biology of peptide hormone action.
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Affiliation(s)
- Gemma Pujadas
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Daniel J Drucker
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
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Maddila SC, Busch-Dienstfertig M, Stein C. B Lymphocytes Express Pomc mRNA, Processing Enzymes and β-Endorphin in Painful Inflammation. J Neuroimmune Pharmacol 2016; 12:180-186. [DOI: 10.1007/s11481-016-9715-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 10/20/2016] [Indexed: 01/31/2023]
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40
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Hassing HA, Fares S, Larsen O, Pad H, Hauge M, Jones RM, Schwartz TW, Hansen HS, Rosenkilde MM. Biased signaling of lipids and allosteric actions of synthetic molecules for GPR119. Biochem Pharmacol 2016; 119:66-75. [DOI: 10.1016/j.bcp.2016.08.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 08/22/2016] [Indexed: 02/08/2023]
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41
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42
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Stijnen P, Ramos-Molina B, O'Rahilly S, Creemers JWM. PCSK1 Mutations and Human Endocrinopathies: From Obesity to Gastrointestinal Disorders. Endocr Rev 2016; 37:347-71. [PMID: 27187081 DOI: 10.1210/er.2015-1117] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prohormone convertase 1/3, encoded by the PCSK1 gene, is a serine endoprotease that is involved in the processing of a variety of proneuropeptides and prohormones. Humans who are homozygous or compound heterozygous for loss-of-function mutations in PCSK1 exhibit a variable and pleiotropic syndrome consisting of some or all of the following: obesity, malabsorptive diarrhea, hypogonadotropic hypogonadism, altered thyroid and adrenal function, and impaired regulation of plasma glucose levels in association with elevated circulating proinsulin-to-insulin ratio. Recently, more common variants in the PCSK1 gene have been found to be associated with alterations in body mass index, increased circulating proinsulin levels, and defects in glucose homeostasis. This review provides an overview of the endocrinopathies and other disorders observed in prohormone convertase 1/3-deficient patients, discusses the possible biochemical basis for these manifestations of the disease, and proposes a model whereby certain missense mutations in PCSK1 may result in proteins with a dominant negative action.
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Affiliation(s)
- Pieter Stijnen
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Bruno Ramos-Molina
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Stephen O'Rahilly
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - John W M Creemers
- Laboratory for Biochemical Neuroendocrinology (P.S., B.R.-M., J.W.M.C.), Department of Human Genetics, KU Leuven, Leuven 3000, Belgium; and Medical Research Council (MRC) Metabolic Diseases Unit (S.O.), Wellcome Trust-MRC Institute of Metabolic Science, National Institute for Health Research, Cambridge Biomedical Research Centre, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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43
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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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Gupta A, Al-Aubaidy HA, Mohammed BI. Glucose dependent insulinotropic polypeptide and dipeptidyl peptidase inhibitors: Their roles in management of type 2 diabetes mellitus. Diabetes Metab Syndr 2016; 10:S170-S175. [PMID: 27016884 DOI: 10.1016/j.dsx.2016.03.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/05/2016] [Indexed: 12/25/2022]
Abstract
This review paper highlights the major advances investigating the roles of glucose dependent insulinotropic polypeptide and its receptors in glucose metabolism and their potential use in management of type 2 diabetes mellitus. It also focusses on the role of dipeptidyl peptidase-4 inhibitors in the treatment of this disease. This study discussed the recent therapeutic development which have occurred in this field, and also covering the evolvement of the potential treatments for diabetes which can be discovered and implemented in the near future to design an effective therapy for diabetes and prediabetes.
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Affiliation(s)
- Ankit Gupta
- School of Medicine, University of Tasmania, Hobart, Australia
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Fujita Y, Yanagimachi T, Takeda Y, Honjo J, Takiyama Y, Abiko A, Makino Y, Haneda M. Alternative form of glucose-dependent insulinotropic polypepide and its physiology. J Diabetes Investig 2016; 7 Suppl 1:33-7. [PMID: 27186353 PMCID: PMC4854502 DOI: 10.1111/jdi.12445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 11/11/2015] [Indexed: 12/18/2022] Open
Abstract
Glucose‐dependent insulinotropic polypepide (GIP) was first extracted from porcine gut mucosa and identified as “incretin” decades ago. Though early studies have shown the possible GIP isoforms by gel filtration profiles from porcine or human intestinal extracts analyzed by radioimmunoassay (RIA), GIP is currently believed to consist of 42 amino acids (GIP1‐42), which are released from gut K‐cells and promote postprandial insulin release. In fact, GIP1‐42 is usually processed from proGIP by the action of prohormone convertase (PC) 1/3 in the gut. GIP expression is occasionally found in the intestinal glucagon‐like peptide‐1‐secreting cells, suggesting gene expression of both GIP and proglucagon can co‐exist in identical cells. However, GIP1‐42 immunoreactivity is rarely found in α‐cells or other pancreatic endocrine cells of wild‐type mammals. Interestingly, we found that short‐form GIP1‐30 is expressed in and released from pancreatic α‐cells and a subset of enteroendocrine cells through proGIP processing by PC2. GIP1‐30 is also insulinotropic and modulates glucose‐stimulated insulin secretion in a paracrine manner. It is also suggested that short‐form GIP1‐30 possibly plays a crucial role for the islet development. It has not been well elucidated whether expression of GIP1‐30 is modulated in the diabetic status, and whether GIP1‐30 might have therapeutic potentials. Our preliminary data suggest that short‐form GIP1‐30 might play important roles in glucose metabolism.
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Affiliation(s)
- Yukihiro Fujita
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Tsuyoshi Yanagimachi
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Yasutaka Takeda
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Jun Honjo
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Yumi Takiyama
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Atsuko Abiko
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Yuichi Makino
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Masakazu Haneda
- Division of Metabolism and Biosystemic Science Department of Internal Medicine Asahikawa Medical University Asahikawa Hokkaido Japan
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46
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Ramos-Molina B, Martin MG, Lindberg I. PCSK1 Variants and Human Obesity. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 140:47-74. [PMID: 27288825 DOI: 10.1016/bs.pmbts.2015.12.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PCSK1, encoding prohormone convertase 1/3 (PC1/3), was one of the first genes linked to monogenic early-onset obesity. PC1/3 is a protease involved in the biosynthetic processing of a variety of neuropeptides and prohormones in endocrine tissues. PC1/3 activity is essential for the activating cleavage of many peptide hormone precursors implicated in the regulation of food ingestion, glucose homeostasis, and energy homeostasis, for example, proopiomelanocortin, proinsulin, proglucagon, and proghrelin. A large number of genome-wide association studies in a variety of different populations have now firmly established a link between three PCSK1 polymorphisms frequent in the population and increased risk of obesity. Human subjects with PC1/3 deficiency, a rare autosomal-recessive disorder caused by the presence of loss-of-function mutations in both alleles, are obese and display a complex set of endocrinopathies. Increasing numbers of genetic diagnoses of infants with persistent diarrhea has recently led to the finding of many novel PCSK1 mutations. PCSK1-deficient infants experience severe intestinal malabsorption during the first years of life, requiring controlled nutrition; these children then become hyperphagic, with associated obesity. The biochemical characterization of novel loss-of-function PCSK1 mutations has resulted in the discovery of new pathological mechanisms affecting the cell biology of the endocrine cell beyond simple loss of enzyme activity, for example, dominant-negative effects of certain mutants on wild-type PC1/3 protein, and activation of the cellular unfolded protein response by endoplasmic reticulum-retained mutants. A better understanding of these molecular and cellular pathologies may illuminate possible treatments for the complex endocrinopathy of PCSK1 deficiency, including obesity.
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Affiliation(s)
- B Ramos-Molina
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - M G Martin
- Department of Pediatrics, Division of Gastroenterology and Nutrition, Mattel Children's Hospital and the David Geffen School of Medicine, Los Angeles, CA, United States of America
| | - I Lindberg
- Department of Anatomy and Neurobiology, University of Maryland, Baltimore, MD, United States of America.
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47
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Incretins and bone: friend or foe? Curr Opin Pharmacol 2015; 22:72-8. [DOI: 10.1016/j.coph.2015.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 03/26/2015] [Accepted: 03/31/2015] [Indexed: 12/25/2022]
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48
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Kuhre RE, Wewer Albrechtsen NJ, Hartmann B, Deacon CF, Holst JJ. Measurement of the incretin hormones: glucagon-like peptide-1 and glucose-dependent insulinotropic peptide. J Diabetes Complications 2015; 29:445-50. [PMID: 25623632 DOI: 10.1016/j.jdiacomp.2014.12.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 12/06/2014] [Accepted: 12/09/2014] [Indexed: 10/24/2022]
Abstract
The two incretin hormones, glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), are secreted from the gastrointestinal tract in response to meals and contribute to the regulation of glucose homeostasis by increasing insulin secretion. Assessment of plasma concentrations of GLP-1 and GIP is often an important endpoint in both clinical and preclinical studies and, therefore, accurate measurement of these hormones is important. Here, we provide an overview of current approaches for the measurement of the incretin hormones, with particular focus on immunological methods.
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Affiliation(s)
- Rune Ehrenreich Kuhre
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DK-2200 Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Nicolai Jacob Wewer Albrechtsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DK-2200 Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Bolette Hartmann
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DK-2200 Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Carolyn F Deacon
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DK-2200 Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Jens Juul Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DK-2200 Copenhagen, Denmark; Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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49
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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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50
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Blanco EH, Peinado JR, Martín MG, Lindberg I. Biochemical and cell biological properties of the human prohormone convertase 1/3 Ser357Gly mutation: a PC1/3 hypermorph. Endocrinology 2014; 155:3434-47. [PMID: 24932808 PMCID: PMC4138575 DOI: 10.1210/en.2013-2151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Satiety and appetite signaling are accomplished by circulating peptide hormones. These peptide hormones require processing from larger precursors to become bioactive, often by the proprotein convertase 1/3 (PC1/3). Several subcellular maturation steps are necessary for PC1/3 to achieve its optimal enzymatic activity. Certain PC1/3 variants found in the general population slightly attenuate its enzymatic activity and are associated with obesity and diabetes. However, mutations that increase PC1/3 activity and/or affect its specificity could also have physiological consequences. We here present data showing that the known human Ser357Gly PC1/3 mutant (PC1/3(S357G)) represents a PC1/3 hypermorph. Conditioned media from human embryonic kidney-293 cells transfected with PC1/3(WT) and PC1/3(S357G) were collected and enzymatic activity characterized. PC1/3(S357G) exhibited a lower calcium dependence; a higher pH optimum (neutral); and a higher resistance to peptide inhibitors than the wild-type enzyme. PC1/3(S357G) exhibited increased cleavage to the C-terminally truncated form, and kinetic parameters of the full-length and truncated mutant enzymes were also altered. Lastly, the S357G mutation broadened the specificity of the enzyme; we detected PC2-like specificity on the substrate proCART, the precursor of the cocaine- and amphetamine regulated transcript neuropeptide known to be associated with obesity. The production of another anorexigenic peptide normally synthesized only by PC2, αMSH, was increased when proopiomelanocortin was coexpressed with PC1/3(S357G). Considering the aberrant enzymatic profile of PC1/3(S357G), we hypothesize that this enzyme possesses unusual processing activity that may significantly change the profile of circulating peptide hormones.
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Affiliation(s)
- Elias H Blanco
- Department of Anatomy and Neurobiology (E.H.B., J.R.P., I.L.), University of Maryland Medical School, Baltimore, Maryland 21201; and Department of Pediatrics (M.G.M.), Division of Gastroenterology and Nutrition, Mattel Children's Hospital and the David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
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