1
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Qiao L, Lu C, Zang T, Dzyuba B, Shao J. Maternal GLP-1 receptor activation inhibits fetal growth. Am J Physiol Endocrinol Metab 2024; 326:E268-E276. [PMID: 38197791 PMCID: PMC11193516 DOI: 10.1152/ajpendo.00361.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 01/11/2024]
Abstract
Glucagon-like peptide 1 (GLP-1) regulates food intake, insulin production, and metabolism. Our recent study demonstrated that pancreatic α-cells-secreted (intraislet) GLP-1 effectively promotes maternal insulin secretion and metabolic adaptation during pregnancy. However, the role of circulating GLP-1 in maternal energy metabolism remains largely unknown. Our study aims to investigate systemic GLP-1 response to pregnancy and its regulatory effect on fetal growth. Using C57BL/6 mice, we observed a gradual decline in maternal blood GLP-1 concentrations. Subsequent administration of the GLP-1 receptor agonist semaglutide (Sem) to dams in late pregnancy revealed a modest decrease in maternal food intake during initial treatment. At the same time, no significant alterations were observed in maternal body weight or fat mass. Notably, Sem-treated dams exhibited a significant decrease in fetal body weight, which persisted even following the restoration of maternal blood glucose levels. Despite no observable change in placental weight, a marked reduction in the placenta labyrinth area from Sem-treated dams was evident. Our investigation further demonstrated a substantial decrease in the expression levels of various pivotal nutrient transporters within the placenta, including glucose transporter one and sodium-neutral amino acid transporter one, after Sem treatment. In addition, Sem injection led to a notable reduction in the capillary area, number, and surface densities within the labyrinth. These findings underscore the crucial role of modulating circulating GLP-1 levels in maternal adaptation, emphasizing the inhibitory effects of excessive GLP-1 receptor activation on both placental development and fetal growth.NEW & NOTEWORTHY Our study reveals a progressive decline in maternal blood glucagon-like peptide 1 (GLP-1) concentration. GLP-1 receptor agonist injection in late pregnancy significantly reduced fetal body weight, even after restoration of maternal blood glucose concentration. GLP-1 receptor activation significantly reduced the placental labyrinth area, expression of some nutrient transporters, and capillary development. Our study indicates that reducing maternal blood GLP-1 levels is a physiological adaptation process that benefits placental development and fetal growth.
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Affiliation(s)
- Liping Qiao
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Cindy Lu
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Tianyi Zang
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Brianna Dzyuba
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Jianhua Shao
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
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2
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Ramasamy I. Physiological Appetite Regulation and Bariatric Surgery. J Clin Med 2024; 13:1347. [PMID: 38546831 PMCID: PMC10932430 DOI: 10.3390/jcm13051347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/22/2024] [Accepted: 02/24/2024] [Indexed: 04/10/2024] Open
Abstract
Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.
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Affiliation(s)
- Indra Ramasamy
- Department of Blood Sciences, Conquest Hospital, Hastings TN37 7RD, UK
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3
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Jiang H, Zang L. GLP-1/GLP-1RAs: New Options for the Drug Treatment of NAFLD. Curr Pharm Des 2024; 30:100-114. [PMID: 38532322 DOI: 10.2174/0113816128283153231226103218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 12/14/2023] [Indexed: 03/28/2024]
Abstract
Non-alcoholic fatty liver disease (NAFLD) has recently emerged as a global public health concern. Currently, the cornerstone of NAFLD treatment is lifestyle modification and, if necessary, weight loss. However, compliance is a challenge, and this approach alone may not be sufficient to halt and treat the more serious disease development, so medication is urgently needed. Nevertheless, no medicines are approved to treat NAFLD. Glucagon-like peptide-1 (GLP-1) is an enteropeptide hormone that inhibits glucagon synthesis, promotes insulin secretion, and delays gastric emptying. GLP-1 has been found in recent studies to be beneficial for the management of NAFLD, and the marketed GLP-1 agonist drugs have different degrees of effectiveness for NAFLD while lowering blood glucose. In this article, we review GLP-1 and its physiological roles, the pathogenesis of NAFLD, the correlation between NAFLD and GLP-1 signaling, and potential strategies for GLP-1 treatment of NAFLD.
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Affiliation(s)
- Haoran Jiang
- Laboratory of Pharmacology, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Linquan Zang
- Laboratory of Pharmacology, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
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4
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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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5
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Ribeiro-Silva JC, Tavares CAM, Girardi ACC. The blood pressure lowering effects of glucagon-like peptide-1 receptor agonists: A mini-review of the potential mechanisms. Curr Opin Pharmacol 2023; 69:102355. [PMID: 36857807 DOI: 10.1016/j.coph.2023.102355] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 01/10/2023] [Accepted: 01/27/2023] [Indexed: 03/03/2023]
Abstract
The incretin hormone glucagon-like peptide 1 (GLP-1) is a key component of the signaling mechanisms promoting glucose homeostasis. Clinical and experimental studies demonstrated that GLP-1 receptor agonists, including GLP-1 itself, have favorable effects on blood pressure and reduce the risk of major cardiovascular events, independently of their effect on glycemic control. GLP-1 receptors are present in the hypothalamus and brainstem, the carotid body, the vasculature, and the kidneys. These organs are involved in blood pressure regulation, have their function altered in hypertension, and are positively benefited by the treatment with GLP-1 receptor agonists. Here, we discuss the potential mechanisms whereby activation of GLP-1R signaling exerts blood pressure-lowering effects beyond glycemic control.
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Affiliation(s)
- Joao Carlos Ribeiro-Silva
- Laboratório de Genética e Cardiologia Molecular, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Caio A M Tavares
- Unidade de Cardiogeriatria, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil; Academic Research Organization (ARO), Hospital Israelita Albert Einstein, São Paulo, São Paulo, Brazil
| | - Adriana C C Girardi
- Laboratório de Genética e Cardiologia Molecular, Instituto do Coração (InCor), Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
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6
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Links between Metabolic Syndrome and Hypertension: The Relationship with the Current Antidiabetic Drugs. Metabolites 2023; 13:metabo13010087. [PMID: 36677012 PMCID: PMC9863091 DOI: 10.3390/metabo13010087] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
Hypertension poses a significant burden in the general population, being responsible for increasing cardiovascular morbidity and mortality, leading to adverse outcomes. Moreover, the association of hypertension with dyslipidaemia, obesity, and insulin resistance, also known as metabolic syndrome, further increases the overall cardiovascular risk of an individual. The complex pathophysiological overlap between the components of the metabolic syndrome may in part explain how novel antidiabetic drugs express pleiotropic effects. Taking into consideration that a significant proportion of patients do not achieve target blood pressure values or glucose levels, more efforts need to be undertaken to increase awareness among patients and physicians. Novel drugs, such as incretin-based therapies and renal glucose reuptake inhibitors, show promising results in decreasing cardiovascular events in patients with metabolic syndrome. The effects of sodium-glucose co-transporter-2 inhibitors are expressed at different levels, including renoprotection through glucosuria, natriuresis and decreased intraglomerular pressure, metabolic effects such as enhanced insulin sensitivity, cardiac protection through decreased myocardial oxidative stress and, to a lesser extent, decreased blood pressure values. These pleiotropic effects are also observed after treatment with glucagon-like peptide-1 receptor agonists, positively influencing the cardiovascular outcomes of patients with metabolic syndrome. The initial combination of the two classes may be the best choice in patients with type 2 diabetes mellitus and multiple cardiovascular risk factors because of their complementary mechanisms of action. In addition, the novel mineralocorticoid receptor antagonists show significant cardio-renal benefits, as well as anti-inflammatory and anti-fibrotic effects. Overall, the key to better control of hypertension in patients with metabolic syndrome is to consider targeting multiple pathogenic mechanisms, using a combination of the different therapeutic agents, as well as drastic lifestyle changes. This article will briefly summarize the association of hypertension with metabolic syndrome, as well as take into account the influence of antidiabetic drugs on blood pressure control.
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7
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Abdalqadir N, Adeli K. GLP-1 and GLP-2 Orchestrate Intestine Integrity, Gut Microbiota, and Immune System Crosstalk. Microorganisms 2022; 10:microorganisms10102061. [PMID: 36296337 PMCID: PMC9610230 DOI: 10.3390/microorganisms10102061] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 12/15/2022] Open
Abstract
The intestine represents the body’s largest interface between internal organs and external environments except for its nutrient and fluid absorption functions. It has the ability to sense numerous endogenous and exogenous signals from both apical and basolateral surfaces and respond through endocrine and neuronal signaling to maintain metabolic homeostasis and energy expenditure. The intestine also harbours the largest population of microbes that interact with the host to maintain human health and diseases. Furthermore, the gut is known as the largest endocrine gland, secreting over 100 peptides and other molecules that act as signaling molecules to regulate human nutrition and physiology. Among these gut-derived hormones, glucagon-like peptide 1 (GLP-1) and -2 have received the most attention due to their critical role in intestinal function and food absorption as well as their application as key drug targets. In this review, we highlight the current state of the literature that has brought into light the importance of GLP-1 and GLP-2 in orchestrating intestine–microbiota–immune system crosstalk to maintain intestinal barrier integrity, inflammation, and metabolic homeostasis.
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Affiliation(s)
- Nyan Abdalqadir
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1H3, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biology, College of Science, University of Sulaimani, Sulaymaniyah 46001, Iraq
| | - Khosrow Adeli
- Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, ON M5G 1H3, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence:
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8
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Brubaker PL. The Molecular Determinants of Glucagon-like Peptide Secretion by the Intestinal L cell. Endocrinology 2022; 163:6717959. [PMID: 36156130 DOI: 10.1210/endocr/bqac159] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Indexed: 11/19/2022]
Abstract
The intestinal L cell secretes a diversity of biologically active hormones, most notably the glucagon-like peptides, GLP-1 and GLP-2. The highly successful introduction of GLP-1-based drugs into the clinic for the treatment of patients with type 2 diabetes and obesity, and of a GLP-2 analog for patients with short bowel syndrome, has led to the suggestion that stimulation of the endogenous secretion of these peptides may serve as a novel therapeutic approach in these conditions. Situated in the intestinal epithelium, the L cell demonstrates complex relationships with not only circulating, paracrine, and neural regulators, but also ingested nutrients and other factors in the lumen, most notably the microbiota. The integrated input from these numerous secretagogues results in a variety of temporal patterns in L cell secretion, ranging from minutes to 24 hours. This review combines the findings of traditional, physiological studies with those using newer molecular approaches to describe what is known and what remains to be elucidated after 5 decades of research on the intestinal L cell and its secreted peptides, GLP-1 and GLP-2.
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Affiliation(s)
- Patricia L Brubaker
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
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9
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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: 135] [Impact Index Per Article: 45.0] [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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10
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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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11
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Holst JJ, Andersen DB, Grunddal KV. Actions of glucagon-like peptide-1 receptor ligands in the gut. Br J Pharmacol 2021; 179:727-742. [PMID: 34235727 DOI: 10.1111/bph.15611] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/31/2021] [Accepted: 06/13/2021] [Indexed: 12/11/2022] Open
Abstract
The incretin hormone glucagon-like peptide-1 (GLP-1) is inactivated by the enzyme dipeptidyl peptidase-4 even before it leaves the gut, but it seems to act predominantly via activation of intestinal sensory neurons expressing GLP-1 receptors. Thus, activation of vagal afferents is probably responsible for its effects on appetite and food intake, gastrointestinal secretion and motility, and pancreatic endocrine secretion. However, GLP-1 receptors are widely expressed in the gastrointestinal (GI) tract, including epithelial cells in the stomach, and the Brunner glands, in endocrine cells of the gut epithelium, and on mucosal lymphocytes. In this way, GLP-1 may have important local actions of epithelial protection and endocrine signalling and may interact with the immune system. We review the formation and release of GLP-1 from the endocrine L cells and its fate after release and describe the localization of its receptor throughout the GI tract and discuss its direct or indirect actions in the GI tract.
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Affiliation(s)
- Jens Juul Holst
- Department of Biomedical Sciences and NovoNordisk Foundation Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Bjørklund Andersen
- Department of Biomedical Sciences and NovoNordisk Foundation Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kaare Villum Grunddal
- Department of Biomedical Sciences and NovoNordisk Foundation Center for Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Maligłówka M, Bułdak Ł, Okopień B, Bołdys A. The consequences of PCSK9 inhibition in selected tissues. POSTEP HIG MED DOSW 2021. [DOI: 10.5604/01.3001.0014.9127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is one of nine members of the proprotein
convertase family. These serine proteases play a pivotal role in the post-translational
modification of proteins and the activation of hormones, enzymes, transcription factors and
growth factors. As a result, they participate in many physiological processes like embryogenesis,
activity of central nervous system and lipid metabolism. Scientific studies show
that the family of convertases is also involved in the pathogenesis of viral and bacterial
infections, osteoporosis, hyperglycaemia, cardiovascular diseases, neurodegenerative disorders
and cancer. The inhibition of PCSK9 by two currently approved for use monoclonal
antibodies (alirocumab, evolocumab) slows down the degradation of low-density lipoprotein
cholesterol receptors (LDLRs). This leads to increased density of LDLRs on the surface
of hepatocytes, resulting in decreased level of low-density lipoprotein cholesterol (LDL-C)
in the bloodstream, which is connected with the reduction of cardiovascular risk. PCSK9 inhibitors (PCSK9i) were created for the patients who could not achieve appropriate level
of LDL-C using current statin and ezetimibe therapy. It seems that high therapeutic efficacy
of PCSK9i will make them more common in the clinical use. The pleiotropic effects
of previously mentioned lipid-lowering therapies were the reasons for literature review of
possible positive and negative effects of PCSK9 inhibition beyond cholesterol metabolism.
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Affiliation(s)
- Mateusz Maligłówka
- Katedra Farmakologii, Klinika Chorób Wewnętrznych i Farmakologii Klinicznej, Wydział Nauk Medycznych Śląskiego Uniwersytetu Medycznego w Katowicach
| | - Łukasz Bułdak
- Katedra Farmakologii, Klinika Chorób Wewnętrznych i Farmakologii Klinicznej, Wydział Nauk Medycznych Śląskiego Uniwersytetu Medycznego w Katowicach
| | - Bogusław Okopień
- Katedra Farmakologii, Klinika Chorób Wewnętrznych i Farmakologii Klinicznej, Wydział Nauk Medycznych Śląskiego Uniwersytetu Medycznego w Katowicach
| | - Aleksandra Bołdys
- Katedra Farmakologii, Klinika Chorób Wewnętrznych i Farmakologii Klinicznej, Wydział Nauk Medycznych Śląskiego Uniwersytetu Medycznego w Katowicach
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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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14
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Guan Y, Sun H, Chen H, Li P, Shan Y, Li X. Physicochemical characterization and the hypoglycemia effects of polysaccharide isolated from Passiflora edulis Sims peel. Food Funct 2021; 12:4221-4230. [PMID: 33876796 DOI: 10.1039/d0fo02965c] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
One polysaccharide, designated as WPEP-A, was isolated from Passiflora edulis Sims peel and its hypoglycemic effects on diabetic db/db mice were evaluated. Physicochemical characterization showed that WPEP-A was composed of galactose, glucose, xylose, rhamnose, galacturonic acid and glucuronic acid with a molecular weight of 9.51 × 104 Da. We observed an inhibition in weight gain and blood glucose levels. Glucose tolerance and insulin tolerance improved after the administration of WPEP-A. In addition, our data showed increased antioxidant enzyme activities. Furthermore, the levels of serum insulin and triglyceride decreased with the recovery of liver damage. Meanwhile, positive changes in short chain fatty acid content were observed, and the mRNA levels of glucagon-like peptide 1 receptor, glucagon and prohormone convertase 3 were up-regulated in the intestinal tract. In summary, our results showed that WPEP-A had hypoglycemic activity and improved intestinal function in diabetic mice, which may contribute to the attenuation of the hypoglycemia effects.
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Affiliation(s)
- Yuan Guan
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi 541006, China.
| | - Hefei Sun
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi 541006, China.
| | - Huiying Chen
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi 541006, China.
| | - Peijun Li
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi 541006, China.
| | - Yang Shan
- Hunan Agricultural Product Processing Institute, Hunan Academy of Agricultural Sciences, Changsha, Hunan 410125, China
| | - Xia Li
- College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, Guangxi 541006, China.
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15
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Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
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Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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16
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Abstract
Glucagon-Like Peptide-1 (GLP-1) is an important peptide hormone secreted by L-cells in the gastrointestinal tract in response to nutrients. It is produced by the differential cleavage of the proglucagon peptide. GLP-1 elicits a wide variety of physiological responses in many tissues that contribute to metabolic homeostasis. For these reasons, therapies designed to either increase endogenous GLP-1 levels or introduce exogenous peptide mimetics are now widely used in the management of diabetes. In addition to GLP-1 production from L-cells, recent reports suggest that pancreatic islet alpha cells may also synthesize and secrete GLP-1. Intra-islet GLP-1 may therefore play an unappreciated role in islet health and glucose regulation, suggesting a potential functional paracrine role for islet-derived GLP-1. In this review, we assess the current literature from an islet-centric point-of-view to better understand the production, degradation, and actions of GLP-1 within the endocrine pancreas in rodents and humans. The relevance of intra-islet GLP-1 in human physiology is discussed regarding the potential role of intra-islet GLP-1 in islet health and dysfunction.
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Affiliation(s)
- Scott A. Campbell
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal Diabetes Research Centre CRCHUM, Montréal, Canada
| | - Janyne Johnson
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Peter E. Light
- Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- CONTACT Peter E. Light Alberta Diabetes Institute, Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2E1, Canada
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Teitelman G. Human Islets Contain a Beta Cell Type That Expresses Proinsulin But Not the Enzyme That Converts the Precursor to Insulin. J Histochem Cytochem 2021; 68:691-702. [PMID: 32998631 DOI: 10.1369/0022155420961361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In pancreatic beta cells, proinsulin (ProIN) undergoes folding in endoplasmic reticulum/Golgi system and is translocated to secretory vesicles for processing into insulin and C-peptide by the proprotein convertases (PC)1/3 and PC2, and carboxypeptidase E. Human beta cells show significant variation in the level of expression of PC1/3, the critical proconvertase involved in proinsulin processing. To ascertain whether this heterogeneity is correlated with the level of expression of the prohormone and mature hormone, the expression of proinsulin, insulin, and PC1/3 in human beta cells was examined. This analysis identified a human beta cell type that expressed proinsulin but lacked PC1/3 (ProIN+PC1/3-). This beta cell type is absent in rodent islets and is abundant in human islets of adults but scarce in islets from postnatal donors. Human islets also contained a beta cell type that expressed both proinsulin and variable levels of PC1/3 (ProIN+PC1/3+) and a less abundant cell type that lacked proinsulin but expressed the convertase (ProIN-PC1/3+). These cell phenotypes were altered by type 2 diabetes. These data suggest that these three cell types represent different stages of a dynamic process with proinsulin folding in ProIN+PC1/3- cells, proinsulin conversion into insulin in ProIN+PC1/3+cells, and replenishment of the proinsulin content in ProIN-PC1/3+ cells.
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Affiliation(s)
- Gladys Teitelman
- Department of Cell Biology, SUNY Downstate Health Science University, Brooklyn, New York
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18
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Li QX, Gao H, Guo YX, Wang BY, Hua RX, Gao L, Shang HW, Lu X, Xu JD. GLP-1 and Underlying Beneficial Actions in Alzheimer's Disease, Hypertension, and NASH. Front Endocrinol (Lausanne) 2021; 12:721198. [PMID: 34552561 PMCID: PMC8450670 DOI: 10.3389/fendo.2021.721198] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 08/23/2021] [Indexed: 12/24/2022] Open
Abstract
GLP-1 is derived from intestinal L cells, which takes effect through binding to GLP-1R and is inactivated by the enzyme dipeptidyl peptidase-4 (DPP-4). Since its discovery, GLP-1 has emerged as an incretin hormone for its facilitation in insulin release and reduction of insulin resistance (IR). However, GLP-1 possesses broader pharmacological effects including anti-inflammation, neuro-protection, regulating blood pressure (BP), and reducing lipotoxicity. These effects are interconnected to the physiological and pathological processes of Alzheimer's disease (AD), hypertension, and non-alcoholic steatohepatitis (NASH). Currently, the underlying mechanism of these effects is still not fully illustrated and a better understanding of them may help identify promising therapeutic targets of AD, hypertension, and NASH. Therefore, we focus on the biological characteristics of GLP-1, render an overview of the mechanism of GLP-1 effects in diseases, and investigate the potential of GLP-1 analogues for the treatment of related diseases in this review.
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Affiliation(s)
- Qiu-Xuan Li
- Clinical Medicine of “5+3” Program, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Han Gao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yue-Xin Guo
- Department of Oral Medicine, Basic Medical College, Capital Medical University, Beijing, China
| | - Bo-Ya Wang
- Eight Program of Clinical Medicine, Peking University Health Science Center, Beijing, China
| | - Rong-xuan Hua
- Clinical Medicine of “5+3” Program, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Lei Gao
- Department of Biomedical Informatics, School of Biomedical Engineering. Capital Medical University, Beijing, China
| | - Hong-Wei Shang
- Morphological Experiment Center, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Xin Lu
- Morphological Experiment Center, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Jing-Dong Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
- *Correspondence: Jing-Dong Xu,
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Galsgaard KD. The Vicious Circle of Hepatic Glucagon Resistance in Non-Alcoholic Fatty Liver Disease. J Clin Med 2020; 9:jcm9124049. [PMID: 33333850 PMCID: PMC7765287 DOI: 10.3390/jcm9124049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/08/2023] Open
Abstract
A key criterion for the most common chronic liver disease—non-alcoholic fatty liver disease (NAFLD)—is an intrahepatic fat content above 5% in individuals who are not using steatogenic agents or having significant alcohol intake. Subjects with NAFLD have increased plasma concentrations of glucagon, and emerging evidence indicates that subjects with NAFLD may show hepatic glucagon resistance. For many years, glucagon has been thought of as the counterregulatory hormone to insulin with a primary function of increasing blood glucose concentrations and protecting against hypoglycemia. However, in recent years, glucagon has re-emerged as an important regulator of other metabolic processes including lipid and amino acid/protein metabolism. This review discusses the evidence that in NAFLD, hepatic glucagon resistance may result in a dysregulated lipid and amino acid/protein metabolism, leading to excess accumulation of fat, hyperglucagonemia, and increased oxidative stress contributing to the worsening/progression of NAFLD.
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Affiliation(s)
- Katrine D. Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; ; Tel.: +45-6044-6145
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
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20
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Pereira de Arruda EH, Vieira da Silva GL, da Rosa-Santos CA, Arantes VC, de Barros Reis MA, Colodel EM, Gaspar de Moura E, Lisboa PC, Carneiro EM, Damazo AS, Latorraca MQ. Protein restriction during pregnancy impairs intra-islet GLP-1 and the expansion of β-cell mass. Mol Cell Endocrinol 2020; 518:110977. [PMID: 32791189 DOI: 10.1016/j.mce.2020.110977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/14/2020] [Accepted: 08/03/2020] [Indexed: 12/26/2022]
Abstract
We evaluated whether protein restriction during pregnancy alters the morphometry of pancreatic islets, the intra-islet glucagon-like peptide-1 (GLP-1) production, and the anti-apoptotic signalling pathway modulated by GLP-1. Control non-pregnant (CNP) and control pregnant (CP) rats were fed a 17% protein diet, and low-protein non-pregnant (LPNP) and low-protein pregnant (LPP) groups were fed a 6% protein diet. The masses of islets and β-cells were similar in the LPNP group and the CNP group but were higher in the CP group than in the CNP group and were equal in the LPP group and the LPNP group. Both variables were lower in the LPP group than in the CP group. Prohormone convertase 2 and GLP-1 fluorescence in α-cells was lower in the low-protein groups than in the control groups. The least PC2/glucagon colocalization was observed in the LPP group, and the most was observed in the CP group. There was less prohormone convertase 1/3/glucagon colocalization in the LPP group than in the CP group. GLP-1/glucagon colocalization was similar in the LPP, CP and CNP groups, which showed less GLP-1/glucagon colocalization than the LPNP group. The mRNA Pka, Creb and Pdx-1 contents were higher in islets from pregnant rats than in islets from non-pregnant rats. Protein restriction during pregnancy impaired the mass of β-cells and the intra-islet GLP-1 production but did not interfere with the transcription of genes of the anti-apoptotic signalling pathway modulated by GLP-1.
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Affiliation(s)
| | | | - Chaiane Aline da Rosa-Santos
- Mestrado em Nutrição, Alimentos e Metabolismo, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Vanessa Cristina Arantes
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | | | - Edson Moleta Colodel
- Departamento de Clínica Médica Veterinária, Faculdade de Agronomia e Medicina Veterinária, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Egberto Gaspar de Moura
- Laboratório de Fisiologia Endócrina, Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Patrícia Cristina Lisboa
- Laboratório de Fisiologia Endócrina, Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Everardo Magalhães Carneiro
- Departamento de Anatomia, Biologia Cellular, Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Amílcar Sabino Damazo
- Departamento de Ciências Básicas da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Márcia Queiroz Latorraca
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil.
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21
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Diz-Chaves Y, Herrera-Pérez S, González-Matías LC, Lamas JA, Mallo F. Glucagon-Like Peptide-1 (GLP-1) in the Integration of Neural and Endocrine Responses to Stress. Nutrients 2020; 12:nu12113304. [PMID: 33126672 PMCID: PMC7692797 DOI: 10.3390/nu12113304] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022] Open
Abstract
Glucagon like-peptide 1 (GLP-1) within the brain is produced by a population of preproglucagon neurons located in the caudal nucleus of the solitary tract. These neurons project to the hypothalamus and another forebrain, hindbrain, and mesolimbic brain areas control the autonomic function, feeding, and the motivation to feed or regulate the stress response and the hypothalamic-pituitary-adrenal axis. GLP-1 receptor (GLP-1R) controls both food intake and feeding behavior (hunger-driven feeding, the hedonic value of food, and food motivation). The activation of GLP-1 receptors involves second messenger pathways and ionic events in the autonomic nervous system, which are very relevant to explain the essential central actions of GLP-1 as neuromodulator coordinating food intake in response to a physiological and stress-related stimulus to maintain homeostasis. Alterations in GLP-1 signaling associated with obesity or chronic stress induce the dysregulation of eating behavior. This review summarized the experimental shreds of evidence from studies using GLP-1R agonists to describe the neural and endocrine integration of stress responses and feeding behavior.
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Affiliation(s)
- Yolanda Diz-Chaves
- CINBIO, Universidade de Vigo, Grupo FB3A, Laboratorio de Endocrinología, 36310 Vigo, Spain;
- Correspondence: (Y.D.-C.); (F.M.); Tel.: +34-(986)-130226 (Y.D.-C.); +34-(986)-812393 (F.M.)
| | - Salvador Herrera-Pérez
- CINBIO, Universidade de Vigo, Grupo FB3B, Laboratorio de Neurociencia, 36310 Vigo, Spain; (S.H.-P.); (J.A.L.)
| | | | - José Antonio Lamas
- CINBIO, Universidade de Vigo, Grupo FB3B, Laboratorio de Neurociencia, 36310 Vigo, Spain; (S.H.-P.); (J.A.L.)
| | - Federico Mallo
- CINBIO, Universidade de Vigo, Grupo FB3A, Laboratorio de Endocrinología, 36310 Vigo, Spain;
- Correspondence: (Y.D.-C.); (F.M.); Tel.: +34-(986)-130226 (Y.D.-C.); +34-(986)-812393 (F.M.)
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22
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Patibandla C, Khan ZI, MacGregor L, Campbell MJ, Patterson S. Costus pictus D. Don leaf extract stimulates GLP-1 secretion from GLUTag L-cells and has cytoprotective effects in BRIN-BD11 β-cells. JOURNAL OF ETHNOPHARMACOLOGY 2020; 260:112970. [PMID: 32422353 DOI: 10.1016/j.jep.2020.112970] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Costus pictus D. Don, commonly known as insulin plant, is a traditional Indian antidiabetic herbal medicine with glucose-lowering and insulin secretory effects having been reported in animal models and humans with Type 2 diabetes. However, its effects on GLP-1 secretion from intestinal endocrine L-cells and potential metabolic and protective effects in insulin secreting pancreatic β-cells are not yet fully understood. AIM OF THE STUDY This study is aimed to elucidate the effects of Costus pictus D. Don leaf extract (CPE) on L-cell function and GLP-1 secretion using the established murine GLUTag L-cell model and to investigate its potential cytoprotective effects against detrimental effects of palmitate and cytokines in pancreatic β-cells using BRIN-BD11 cells. METHODS Costus pictus D. Don dried leaf powder was extracted by soxhlet method. Cell viability was determined by MTT assay. Changes in gene and protein expression were quantified by qPCR and western blotting, respectively. GLP-1 and insulin secretion were measured by ELISA. RESULTS CPE significantly enhanced the percentage of viable BRIN-BD11 and GLUTag cells and protected BRIN-BD11 cells against palmitate- and proinflammatory cytokine-induced toxicity. CPE enhanced acute GLP-1 secretion 6.4-16.3-fold from GLUTag cells at both low (1.1 mM) and high (16.7 mM) glucose (P < 0.01) concentrations. Antioxidant (Nrf2, Cat & Gpx1) and pro-proliferative (Erk1 and Jnk1) gene expression were upregulated by 24 h culture with CPE, while proinflammatory transcription factor NF-κB was downregulated. CONCLUSION Diminished postprandial GLP-1 secretion and loss of insulin secreting β-cells are known contributors of T2DM. Our data suggests that CPE acutely stimulates GLP-1 secretion from L-cells. Long term exposure of the BRIN-BD11 cells to CPE enhances cell number and may protect against palmitate and proinflammatory cytokines by activating multiple pathways. Thus, the current study suggests that the possible antidiabetic properties of CPE may be linked to enhanced GLP-1 secretion and β-cell protection which could be beneficial in the management of T2DM.
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Affiliation(s)
- Chinmai Patibandla
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Zahidul Islam Khan
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Louise MacGregor
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Mark James Campbell
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Steven Patterson
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
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23
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Martins FL, Bailey MA, Girardi ACC. Endogenous Activation of Glucagon-Like Peptide-1 Receptor Contributes to Blood Pressure Control: Role of Proximal Tubule Na +/H + Exchanger Isoform 3, Renal Angiotensin II, and Insulin Sensitivity. Hypertension 2020; 76:839-848. [PMID: 32755467 DOI: 10.1161/hypertensionaha.120.14868] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The pharmacological administration of GLP-1R (glucagon-like peptide-1 receptor) agonists reduces blood pressure (BP) in type 2 diabetes mellitus and nondiabetic patients. This study tested the hypothesis that endogenous GLP-1R signaling influences the regulation of BP. To this end, SHRs (spontaneously hypertensive rats) and Wistar rats were treated with the GLP-1R antagonist Ex9 (exendin-9) or vehicle for 4 weeks. Rats receiving the GLP-1R agonist Ex4 (exenatide) were used as an additional control. We found that blockade of baseline GLP-1R signaling by Ex9 increased systolic BP in both SHR and Wistar rats, compared with vehicle-treated animals, while Ex4 only reduced systolic BP in SHR. Higher systolic BP induced by Ex9 was accompanied by reduced lithium clearance and lower levels of NHE3 (Na+/H+ exchanger isoform 3) phosphorylation at the serine 552, indicative of increased proximal tubule sodium reabsorption. Additionally, urinary AGT (angiotensinogen) and renal cortical concentration of Ang II (angiotensin II) were enhanced by Ex9. Conversely, Ex4 decreased both urinary AGT and cortical Ang II but exclusively in SHRs. Moreover, both SHR and Wistar rats treated with Ex9 displayed hyperinsulinemia as compared with vehicle-treated rats, whereas Ex4 reduced fasting insulin concentration in SHR. Collectively, these results suggest that endogenous GLP-1R signaling exerts a physiologically relevant effect on BP control, which may be attributable, in part, to its tonic actions on the proximal tubule NHE3-mediated sodium reabsorption, intrarenal renin-angiotensin system, and insulin sensitivity. The possible role of impaired GLP-1R signaling in the pathogenesis of hypertension warrants further investigation.
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Affiliation(s)
- Flavia L Martins
- From the Heart Institute (InCor), Medical School, University of São Paulo, Brazil (F.L.M., A.C.C.G.)
| | - Matthew A Bailey
- Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, United Kingdom (M.A.B.)
| | - Adriana C C Girardi
- From the Heart Institute (InCor), Medical School, University of São Paulo, Brazil (F.L.M., A.C.C.G.)
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24
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Ramzy A, Asadi A, Kieffer TJ. Revisiting Proinsulin Processing: Evidence That Human β-Cells Process Proinsulin With Prohormone Convertase (PC) 1/3 but Not PC2. Diabetes 2020; 69:1451-1462. [PMID: 32291281 DOI: 10.2337/db19-0276] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/03/2020] [Indexed: 11/13/2022]
Abstract
Insulin is first produced in pancreatic β-cells as the precursor prohormone proinsulin. Defective proinsulin processing has been implicated in the pathogenesis of both type 1 and type 2 diabetes. Though there is substantial evidence that mouse β-cells process proinsulin using prohormone convertase 1/3 (PC1/3) and then prohormone convertase 2 (PC2), this finding has not been verified in human β-cells. Immunofluorescence with validated antibodies revealed that there was no detectable PC2 immunoreactivity in human β-cells and little PCSK2 mRNA by in situ hybridization. Similarly, rat β-cells were not immunoreactive for PC2. In all histological experiments, PC2 immunoreactivity in neighboring α-cells acted as a positive control. In donors with type 2 diabetes, β-cells had elevated PC2 immunoreactivity, suggesting that aberrant PC2 expression may contribute to impaired proinsulin processing in β-cells of patients with diabetes. To support histological findings using a biochemical approach, human islets were used for pulse-chase experiments. Despite inhibition of PC2 function by temperature blockade, brefeldin A, chloroquine, and multiple inhibitors that blocked production of mature glucagon from proglucagon, β-cells retained the ability to produce mature insulin. Conversely, suppression of PC1/3 blocked processing of proinsulin but not proglucagon. By demonstrating that healthy human β-cells process proinsulin by PC1/3 but not PC2, we suggest that there is a need to revise the long-standing theory of proinsulin processing.
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Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Ali Asadi
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, The University of British Columbia, Vancouver, British Columbia, Canada
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25
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Stemmer K, Finan B, DiMarchi RD, Tschöp MH, Müller TD. Insights into incretin-based therapies for treatment of diabetic dyslipidemia. Adv Drug Deliv Rev 2020; 159:34-53. [PMID: 32485206 DOI: 10.1016/j.addr.2020.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/09/2020] [Accepted: 05/23/2020] [Indexed: 02/07/2023]
Abstract
Derangements in triglyceride and cholesterol metabolism (dyslipidemia) are major risk factors for the development of cardiovascular diseases in obese and type-2 diabetic (T2D) patients. An emerging class of glucagon-like peptide-1 (GLP-1) analogues and next generation peptide dual-agonists such as GLP-1/glucagon or GLP-1/GIP could provide effective therapeutic options for T2D patients. In addition to their role in glucose and energy homeostasis, GLP-1, GIP and glucagon serve as regulators of lipid metabolism. This review summarizes the current knowledge in GLP-1, glucagon and GIP effects on lipid and lipoprotein metabolism and frames the emerging therapeutic benefits of GLP-1 analogs and GLP-1-based multiagonists as add-on treatment options for diabetes associated dyslipidemia.
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Campbell SA, Golec DP, Hubert M, Johnson J, Salamon N, Barr A, MacDonald PE, Philippaert K, Light PE. Human islets contain a subpopulation of glucagon-like peptide-1 secreting α cells that is increased in type 2 diabetes. Mol Metab 2020; 39:101014. [PMID: 32413586 PMCID: PMC7260680 DOI: 10.1016/j.molmet.2020.101014] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 12/16/2022] Open
Abstract
Objectives Our study shows that glucagon-like peptide-1 (GLP-1) is secreted within human islets and may play an unexpectedly important paracrine role in islet physiology and pathophysiology. It is known that α cells within rodent and human pancreatic islets are capable of secreting GLP-1, but little is known about the functional role that islet-derived GLP-1 plays in human islets. Methods We used flow cytometry, immunohistochemistry, perifusions, and calcium imaging techniques to analyse GLP-1 expression and function in islets isolated from cadaveric human donors with or without type 2 diabetes. We also used immunohistochemistry to analyse GLP-1 expression within islets from pancreatic biopsies obtained from living donors. Results We have demonstrated that human islets secrete ∼50-fold more GLP-1 than murine islets and that ∼40% of the total human α cells contain GLP-1. Our results also confirm that dipeptidyl peptidase-4 (DPP4) is expressed in α cells. Sitagliptin increased GLP-1 secretion from cultured human islets but did not enhance glucose-stimulated insulin secretion (GSIS) in islets from non-diabetic (ND) or type 2 diabetic (T2D) donors, suggesting that β cell GLP-1 receptors (GLP-1R) may already be maximally activated. Therefore, we tested the effects of exendin-9, a GLP-1R antagonist. Exendin-9 was shown to reduce GSIS by 39% and 61% in ND islets and T2D islets, respectively. We also observed significantly more GLP-1+ α cells in T2D islets compared with ND islets obtained from cadaveric donors. Furthermore, GLP-1+ α cells were also identified in pancreatic islet sections obtained from living donors undergoing surgery. Conclusions In summary, we demonstrated that human islets secrete robust amounts of GLP-1 from an α cell subpopulation and that GLP-1R signalling may support GSIS to a greater extent in T2D islets. Here we show that glucagon-like peptide-1 (GLP-1) is secreted from a subpopulation of α cells within human islets. Human islets secrete ∼50-fold more GLP-1 than murine islets and that ∼40% of the total human α cells contain GLP-1. We observed significantly more GLP-1+ α cells in islets from donors with type 2 diabetes than in islets from donors with no diabetes. GLP-1+ α cells can also be detected in pancreatic islet sections obtained from living donors undergoing surgery. GLP-1 receptor signaling may support insulin secretion to a greater extent in type 2 diabetes.
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Affiliation(s)
- Scott A Campbell
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Dominic P Golec
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Matt Hubert
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Janyne Johnson
- Alberta Diabetes Institute and the Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Nicole Salamon
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Amy Barr
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Patrick E MacDonald
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Koenraad Philippaert
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada
| | - Peter E Light
- Alberta Diabetes Institute and the Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Canada.
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Kim S, Whitener RL, Peiris H, Gu X, Chang CA, Lam JY, Camunas-Soler J, Park I, Bevacqua RJ, Tellez K, Quake SR, Lakey JRT, Bottino R, Ross PJ, Kim SK. Molecular and genetic regulation of pig pancreatic islet cell development. Development 2020; 147:dev186213. [PMID: 32108026 PMCID: PMC7132804 DOI: 10.1242/dev.186213] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/20/2020] [Indexed: 12/12/2022]
Abstract
Reliance on rodents for understanding pancreatic genetics, development and islet function could limit progress in developing interventions for human diseases such as diabetes mellitus. Similarities of pancreas morphology and function suggest that porcine and human pancreas developmental biology may have useful homologies. However, little is known about pig pancreas development. To fill this knowledge gap, we investigated fetal and neonatal pig pancreas at multiple, crucial developmental stages using modern experimental approaches. Purification of islet β-, α- and δ-cells followed by transcriptome analysis (RNA-seq) and immunohistology identified cell- and stage-specific regulation, and revealed that pig and human islet cells share characteristic features that are not observed in mice. Morphometric analysis also revealed endocrine cell allocation and architectural similarities between pig and human islets. Our analysis unveiled scores of signaling pathways linked to native islet β-cell functional maturation, including evidence of fetal α-cell GLP-1 production and signaling to β-cells. Thus, the findings and resources detailed here show how pig pancreatic islet studies complement other systems for understanding the developmental programs that generate functional islet cells, and that are relevant to human pancreatic diseases.
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Affiliation(s)
- Seokho Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robert L Whitener
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Heshan Peiris
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xueying Gu
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Charles A Chang
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jonathan Y Lam
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Joan Camunas-Soler
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Insung Park
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | - Romina J Bevacqua
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Krissie Tellez
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Stephen R Quake
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94518, USA
| | - Jonathan R T Lakey
- Department of Surgery, University of California at Irvine, Irvine, CA 92868, USA
| | - Rita Bottino
- Institute of Cellular Therapeutics, Allegheny Health Network, Pittsburgh, PA 15212, USA
| | - Pablo J Ross
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | - Seung K Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA 94305, USA
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Davis EM, Sandoval DA. Glucagon‐Like Peptide‐1: Actions and Influence on Pancreatic Hormone Function. Compr Physiol 2020; 10:577-595. [DOI: 10.1002/cphy.c190025] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Muhsin NIA, Bentley L, Bai Y, Goldsworthy M, Cox RD. A novel mutation in the mouse Pcsk1 gene showing obesity and diabetes. Mamm Genome 2020; 31:17-29. [PMID: 31974728 PMCID: PMC7060156 DOI: 10.1007/s00335-020-09826-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/07/2020] [Indexed: 12/14/2022]
Abstract
The proprotein convertase subtilisin/Kexin type 1 (PCSK1/PC1) protein processes inactive pro-hormone precursors into biologically active hormones in a number of neuroendocrine and endocrine cell types. Patients with recessive mutations in PCSK1 exhibit a complex spectrum of traits including obesity, diarrhoea and endocrine disorders. We describe here a new mouse model with a point mutation in the Pcsk1 gene that exhibits obesity, hyperphagia, transient diarrhoea and hyperproinsulinaemia, phenotypes consistent with human patient traits. The mutation results in a pV96L amino acid substitution and changes the first nucleotide of mouse exon 3 leading to skipping of that exon and in homozygotes very little full-length transcript. Overexpression of the exon 3 deleted protein or the 96L protein results in ER retention in Neuro2a cells. This is the second Pcsk1 mouse model to display obesity phenotypes, contrasting knockout mouse alleles. This model will be useful in investigating the basis of endocrine disease resulting from prohormone processing defects.
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Affiliation(s)
- Nor I A Muhsin
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Liz Bentley
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Ying Bai
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Michelle Goldsworthy
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK
| | - Roger D Cox
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire, OX11 0RD, UK.
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Christodoulou MI, Tchoumtchoua J, Skaltsounis AL, Scorilas A, Halabalaki M. Natural Alkaloids Intervening the Insulin Pathway: New Hopes for Anti-Diabetic Agents? Curr Med Chem 2019; 26:5982-6015. [PMID: 29714135 DOI: 10.2174/0929867325666180430152618] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/16/2018] [Accepted: 04/18/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Accumulating experimental data supports the capacity of natural compounds to intervene in complicated molecular pathways underlying the pathogenesis of certain human morbidities. Among them, diabetes is now a world's epidemic associated with increased risk of death; thus, the detection of novel anti-diabetic agents and/or adjuvants is of vital importance. Alkaloids represent a diverse group of natural products with a range of therapeutic properties; during the last 20 years, published research on their anti-diabetic capacity has been tremendously increased. PURPOSE To discuss current concepts on the anti-diabetic impact of certain alkaloids, with special reference to their molecular targets throughout the insulin-signaling pathway. METHODOLOGY Upon in-depth search in the SCOPUS and PUBMED databases, the literature on alkaloids with insulin secretion/sensitization properties was critically reviewed. RESULTS In-vitro and in-vivo evidence supports the effect of berberine, trigonelline, piperine, oxymatrine, vindoneline, evodiamine and neferine on insulin-signaling and related cascades in beta-cells, myocytes, adipocytes, hepatocytes and other cells. Associated receptors, kinases, hormones and cytokines, are affected in terms of gene transcription, protein expression, activity and/or phosphorylation. Pathophysiological processes associated with insulin resistance, beta-cell failure, oxidative stress and inflammation, as well as clinical phenotype are also influenced. DISCUSSION Growing evidence suggests the ability of specific alkaloids to intervene in the insulin-signal transduction pathway, reverse molecular defects resulting in insulin resistance and glucose intolerance and improve disease complications, in-vitro and in-vivo. Future indepth molecular studies are expected to elucidate their exact mechanism of action, while large clinical trials are urgently needed to assess their potential as anti-diabetic agents.
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Affiliation(s)
- Maria-Ioanna Christodoulou
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimioupoli Zografou 15771, Athens, Greece
| | - Job Tchoumtchoua
- Department of Pharmacognosy and Natural Product Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupoli Zografou 15771, Athens, Greece
| | - Alexios-Leandros Skaltsounis
- Department of Pharmacognosy and Natural Product Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupoli Zografou 15771, Athens, Greece
| | - Andreas Scorilas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, National and Kapodistrian University of Athens, Panepistimioupoli Zografou 15771, Athens, Greece
| | - Maria Halabalaki
- Department of Pharmacognosy and Natural Product Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupoli Zografou 15771, Athens, Greece
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Müller TD, Finan B, Bloom SR, D'Alessio D, Drucker DJ, Flatt PR, Fritsche A, Gribble F, Grill HJ, Habener JF, Holst JJ, Langhans W, Meier JJ, Nauck MA, Perez-Tilve D, Pocai A, Reimann F, Sandoval DA, Schwartz TW, Seeley RJ, Stemmer K, Tang-Christensen M, Woods SC, DiMarchi RD, Tschöp MH. Glucagon-like peptide 1 (GLP-1). Mol Metab 2019; 30:72-130. [PMID: 31767182 PMCID: PMC6812410 DOI: 10.1016/j.molmet.2019.09.010] [Citation(s) in RCA: 862] [Impact Index Per Article: 172.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/10/2019] [Accepted: 09/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - B Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - S R Bloom
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - D D'Alessio
- Division of Endocrinology, Duke University Medical Center, Durham, NC, USA
| | - D J Drucker
- The Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Ontario, M5G1X5, Canada
| | - P R Flatt
- SAAD Centre for Pharmacy & Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - A Fritsche
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - F Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - H J Grill
- Institute of Diabetes, Obesity and Metabolism, Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - J J Meier
- Diabetes Division, St Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M A Nauck
- Diabetes Center Bochum-Hattingen, St Josef Hospital (Ruhr-Universität Bochum), Bochum, Germany
| | - D Perez-Tilve
- Department of Internal Medicine, University of Cincinnati-College of Medicine, Cincinnati, OH, USA
| | - A Pocai
- Cardiovascular & ImmunoMetabolism, Janssen Research & Development, Welsh and McKean Roads, Spring House, PA, 19477, USA
| | - F Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - D A Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - T W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DL-2200, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - M Tang-Christensen
- Obesity Research, Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | - S C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - R D DiMarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany; Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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Kaya D, Kaji K, Tsuji Y, Yamashita S, Kitagawa K, Ozutsumi T, Fujinaga Y, Takaya H, Kawaratani H, Moriya K, Namisaki T, Akahane T, Yoshiji H. TGR5 Activation Modulates an Inhibitory Effect on Liver Fibrosis Development Mediated by Anagliptin in Diabetic Rats. Cells 2019; 8:cells8101153. [PMID: 31561561 PMCID: PMC6829474 DOI: 10.3390/cells8101153] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 09/21/2019] [Accepted: 09/24/2019] [Indexed: 12/14/2022] Open
Abstract
Hyperglycemia and hyperinsulinemia activate the proliferative potential of hepatic stellate cells (HSCs) and promote hepatic fibrosis. Dipeptidyl peptidase-4 (DPP-4) inhibitors, antidiabetic agents, reportedly inhibit the HSC proliferation. Additionally, Takeda G protein-coupled receptor 5 (TGR5) agonists induce the systemic release of glucagon-like peptides from intestinal L cells, which maintains glycemic homeostasis. This study assessed the combined effect of TGR5 agonist and DPP-4 inhibitor on diabetes-based liver fibrosis development. Male diabetic rats received intraperitoneal injection of porcine serum (PS) to induce liver fibrosis, and they were orally administered the following agents: oleanolic acid (OA) as a TGR5 agonist, anagliptin (ANA) as a DPP-4 inhibitor, and a combination of both agents. Treatment with OA or ANA significantly improved glycemic status and attenuated intrahepatic steatosis and lipid peroxidation in diabetic rats. PS-induced liver fibrosis development was also drastically suppressed by treatment with either agent, and the combination of both reciprocally enhanced the antifibrotic effect. Fecal microbiome demonstrated that both agents inhibited the increase in the Firmicutes/Bacteroidetes ratio, an indicator of dysbiosis related to metabolic syndromes. Furthermore, ANA directly inhibited in vitro HSC proliferative and profibrogenic activities. Collectively, TGR5 agonist and DPP-4 inhibitor appears to be a novel strategy against liver fibrosis under diabetic conditions.
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Affiliation(s)
- Daisuke Kaya
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Kosuke Kaji
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Yuki Tsuji
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Satoko Yamashita
- Sanwa Kagaku Kenkyusho, Co., Ltd., Nagoya, Aichi 461-8631, Japan.
| | - Koh Kitagawa
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Takahiro Ozutsumi
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Yukihisa Fujinaga
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Hiroaki Takaya
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Hideto Kawaratani
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Kei Moriya
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Tadashi Namisaki
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Takemi Akahane
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
| | - Hitoshi Yoshiji
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8521, Japan.
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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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Contemporary Updates on the Physiology of Glucagon like Peptide-1 and Its Agonist to Treat Type 2 Diabetes Mellitus. Int J Pept Res Ther 2019. [DOI: 10.1007/s10989-019-09927-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
The organs require oxygen and other types of nutrients (amino acids, sugars, and lipids) to function, the heart consuming large amounts of fatty acids for oxidation and adenosine triphosphate (ATP) generation.
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Abstract
Pancreatic alpha cells are generally considered the only source of glucagon secretion in humans. In the 1970s several groups investigating totally pancreatectomised animals reported that glucagon-like immunoreactive material could be detected in the gastrointestinal tract and reopened the question of an extrapancreatic source of glucagon proposed in 1948 when a hyperglycaemic substance was found in the gastrointestinal tract of dogs and rabbits. Nevertheless, over the years, controversy about the existence of extrapancreatic glucagon has flourished as it proved difficult to accurately measure fully processed 29-amino acid glucagon. Recent advances in analytical methods have increased sensitivity and specificity of glucagon assays and, furthermore, technical advances in mass spectrometry-based proteomics have made the detection of low-abundant peptides, such as glucagon, in human plasma more accurate. Here we review new data on extrapancreatic glucagon secretion in the context of historical data and recent analytical breakthroughs. Furthermore, the source, regulation and potential physiological role of extrapancreatic glucagon are discussed and ongoing challenges and knowledge-gaps are outlined.
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Affiliation(s)
- Asger Lund
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark; Department of Medicine, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark.
| | - Filip K Knop
- Clinical Metabolic Physiology, Steno Diabetes Center Copenhagen, Gentofte Hospital, Hellerup, Denmark; Department of Clinical Medicine, 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.
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Deacon CF. Physiology and Pharmacology of DPP-4 in Glucose Homeostasis and the Treatment of Type 2 Diabetes. Front Endocrinol (Lausanne) 2019; 10:80. [PMID: 30828317 PMCID: PMC6384237 DOI: 10.3389/fendo.2019.00080] [Citation(s) in RCA: 197] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022] Open
Abstract
Dipeptidyl peptidase-4 (DPP-4), also known as the T-cell antigen CD26, is a multi-functional protein which, besides its catalytic activity, also functions as a binding protein and a ligand for a variety of extracellular molecules. It is an integral membrane protein expressed on cells throughout the body, but is also shed from the membrane and circulates as a soluble protein in the plasma. A large number of bioactive molecules can be cleaved by DPP-4 in vitro, but only a few of these have been demonstrated to be physiological substrates. One of these is the incretin hormone, glucagon-like peptide-1 (GLP-1), which plays an important role in the maintenance of normal glucose homeostasis, and DPP-4 has been shown to be the key enzyme regulating its biological activity. This pathway has been targeted pharmacologically through the development of DPP-4 inhibitors, and these are now a successful class of anti-hyperglycaemic agents used to treat type 2 diabetes (T2DM). DPP-4 may additionally influence metabolic control via its proteolytic effect on other regulatory peptides, but it has also been reported to affect insulin sensitivity, potentially mediated through its non-enzymatic interactions with other membrane proteins. Given that altered expression and activity of DPP-4 are associated with increasing body mass index and hyperglycaemia, DPP-4 has been proposed to play a role in linking obesity and the pathogenesis of T2DM by functioning as a local mediator of inflammation and insulin resistance in adipose and hepatic tissue. As well as these broader systemic effects, it has also been suggested that DPP-4 may be able to modulate β-cell function as part of a paracrine system involving GLP-1 produced locally within the pancreatic islets. However, while it is evident that DPP-4 has the potential to influence glycaemic control, its overall significance for the normal physiological regulation of glucose homeostasis in humans and its role in the pathogenesis of metabolic disease remain to be established.
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Brandt SJ, Müller TD, DiMarchi RD, Tschöp MH, Stemmer K. Peptide-based multi-agonists: a new paradigm in metabolic pharmacology. J Intern Med 2018; 284:581-602. [PMID: 30230640 DOI: 10.1111/joim.12837] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Obesity and its comorbidities, such as type 2 diabetes, are pressing worldwide health concerns. Available anti-obesity treatments include weight loss pharmacotherapies and bariatric surgery. Whilst surgical interventions typically result in significant and sustained weight loss, available pharmacotherapies are far less effective, typically decreasing body weight by no more than 5-10%. An emerging class of multi-agonist drugs may eventually bridge this gap. This new class of specially tailored drugs hybridizes the amino acid sequences of key metabolic hormones into one single entity with enhanced potency and sustained action. Successful examples of this strategy include multi-agonist drugs targeting the receptors for glucagon-like peptide-1 (GLP-1), glucagon and the glucose-dependent insulinotropic polypeptide (GIP). Due to the simultaneous activity at several metabolically relevant receptors, these multi-agonists offer improved body weight loss and glucose tolerance relative to their constituent monotherapies. Further advancing this concept, chimeras were generated that covalently link nuclear acting hormones such as oestrogen, thyroid hormone (T3 ) or dexamethasone to peptide hormones such as GLP-1 or glucagon. The benefit of this strategy is to restrict the nuclear hormone action exclusively to cells expressing the peptide hormone receptor, thereby maximizing combinatorial metabolic efficacy of both drug constituents in the target cells whilst preventing the nuclear hormone cargo from entering and acting on cells devoid of the peptide hormone receptor, in which the nuclear hormone might have unwanted effects. Many of these multi-agonists are in preclinical and clinical development and may represent new and effective tools in the fight against obesity and its comorbidities.
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Affiliation(s)
- S J Brandt
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - R D DiMarchi
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
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Filippello A, Urbano F, Di Mauro S, Scamporrino A, Di Pino A, Scicali R, Rabuazzo AM, Purrello F, Piro S. Chronic Exposure to Palmitate Impairs Insulin Signaling in an Intestinal L-cell Line: A Possible Shift from GLP-1 to Glucagon Production. Int J Mol Sci 2018; 19:E3791. [PMID: 30487448 PMCID: PMC6321596 DOI: 10.3390/ijms19123791] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 12/11/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2DM) are characterized by insulin resistance and impaired glucagon-like peptide-1 (GLP-1) secretion/function. Lipotoxicity, a chronic elevation of free fatty acids in the blood, could affect insulin-signaling in many peripheral tissues. To date, the effects of lipotoxicity on the insulin receptor and insulin resistance in the intestinal L-cells need to be elucidated. Moreover, recent observations indicate that L-cells may be able to process not only GLP-1 but also glucagon from proglucagon. The aim of this study was to investigate the effects of chronic palmitate exposure on insulin pathways, GLP-1 secretion and glucagon synthesis in the GLUTag L-cell line. Cells were cultured in the presence/absence of palmitate (0.5 mM) for 24 h to mimic lipotoxicity. Palmitate treatment affected insulin-stimulated GLP-1 secretion, insulin receptor phosphorylation and IRS-1-AKT pathway signaling. In our model lipotoxicity induced extracellular signal-regulated kinase (ERK 44/42) activation both in insulin stimulated and basal conditions and also up-regulated paired box 6 (PAX6) and proglucagon expression (Gcg). Interestingly, palmitate treatment caused an increased glucagon secretion through the up-regulation of prohormone convertase 2. These results indicate that a state of insulin resistance could be responsible for secretory alterations in L-cells through the impairment of insulin-signaling pathways. Our data support the hypothesis that lipotoxicity might contribute to L-cell deregulation.
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Affiliation(s)
- Agnese Filippello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Francesca Urbano
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Stefania Di Mauro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Alessandra Scamporrino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Antonino Di Pino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Roberto Scicali
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Agata Maria Rabuazzo
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Francesco Purrello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Salvatore Piro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
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Brubaker PL. Glucagon‐like Peptide‐2 and the Regulation of Intestinal Growth and Function. Compr Physiol 2018; 8:1185-1210. [DOI: 10.1002/cphy.c170055] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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41
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Roberts GP, Kay RG, Howard J, Hardwick RH, Reimann F, Gribble FM. Gastrectomy with Roux-en-Y reconstruction as a lean model of bariatric surgery. Surg Obes Relat Dis 2018; 14:562-568. [PMID: 29548882 PMCID: PMC6191023 DOI: 10.1016/j.soard.2018.01.039] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/21/2017] [Accepted: 01/29/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Altered enteroendocrine hormone responses are widely believed to underlie the beneficial effects of bariatric surgery in type 2 diabetes. While elevated postprandial glucagon-like peptide-1 (GLP-1) is considered one of the mediators, increased postprandial glucagon levels have recently been implicated. OBJECTIVES We investigated hormonal responses in lean patients after prophylactic total gastrectomy (PTG), as a model of Roux-en-Y gastric bypass without the confounding effects of obesity or massive weight loss. SETTING University hospital, United Kingdom. METHODS Ten participants after PTG and 9 healthy volunteers were recruited for oral glucose tolerance tests. Plasma glucose, insulin, GLP-1, peptide YY, glucose-dependent insulinotropic-polypeptide, glucagon, oxyntomodulin, glucagon(1-61), and glicentin levels were assessed using immunoassays and/or mass spectrometry. RESULTS PTG participants exhibited accelerated plasma glucose appearance, followed, in 3 of 10 cases, by hypoglycemia (<3 mM glucose). Plasma GLP-1, peptide YY, glucose-dependent insulinotropic-polypeptide, glicentin, and oxyntomodulin responses were elevated, and glucagon appeared to rise in PTG participants when measured with a glucagon-specific enzyme-linked immunosorbent assay. We revisited the specificity of this assay, and demonstrated significant cross-reactivity with glicentin and oxyntomodulin at concentrations observed in PTG plasma. Reassessment of glucagon with the same assay using a modified protocol, and by liquid chromatography-mass spectrometry, demonstrated suppression of glucagon secretion after oral glucose tolerance tests in both PTG and control cohorts. CONCLUSIONS Care should be taken when assessing glucagon levels in the presence of elevated plasma levels of other proglucagon products. Substantial elevation of GLP-1 and insulin responses after PTG likely contribute to the observed hypoglycemia, and mirror similar hormone levels and complications observed in bariatric weight loss patients.
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Affiliation(s)
- Geoffrey P Roberts
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom; Cambridge Oesophago-gastric centre, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Richard G Kay
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - James Howard
- LGC Limited, Newmarket Road, Fordham, Cambridgeshire, United Kingdom
| | - Richard H Hardwick
- Cambridge Oesophago-gastric centre, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Frank Reimann
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Fiona M Gribble
- Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom.
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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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Traub S, Meier DT, Schulze F, Dror E, Nordmann TM, Goetz N, Koch N, Dalmas E, Stawiski M, Makshana V, Thorel F, Herrera PL, Böni-Schnetzler M, Donath MY. Pancreatic α Cell-Derived Glucagon-Related Peptides Are Required for β Cell Adaptation and Glucose Homeostasis. Cell Rep 2017; 18:3192-3203. [PMID: 28355570 DOI: 10.1016/j.celrep.2017.03.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/22/2017] [Accepted: 03/01/2017] [Indexed: 02/04/2023] Open
Abstract
Pancreatic α cells may process proglucagon not only to glucagon but also to glucagon-like peptide-1 (GLP-1). However, the biological relevance of paracrine GLP-1 for β cell function remains unclear. We studied effects of locally derived insulin secretagogues on β cell function and glucose homeostasis using mice with α cell ablation and with α cell-specific GLP-1 deficiency. Normally, intestinal GLP-1 compensates for the lack of α cell-derived GLP-1. However, upon aging and metabolic stress, glucose tolerance is impaired. This was partly rescued with the DPP-4 inhibitor sitagliptin, but not with glucagon administration. In isolated islets from these mice, glucose-stimulated insulin secretion was heavily impaired and exogenous GLP-1 or glucagon rescued insulin secretion. These data highlight the importance of α cell-derived GLP-1 for glucose homeostasis during metabolic stress and may impact on the clinical use of systemic GLP-1 agonists versus stabilizing local α cell-derived GLP-1 by DPP-4 inhibitors in type 2 diabetes.
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Affiliation(s)
- Shuyang Traub
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Daniel T Meier
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Friederike Schulze
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Erez Dror
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Thierry M Nordmann
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Nicole Goetz
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Norina Koch
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Elise Dalmas
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Marc Stawiski
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Valmir Makshana
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland; Centre facultaire du diabète, University of Geneva, 1211 Geneva, Switzerland
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland; Centre facultaire du diabète, University of Geneva, 1211 Geneva, Switzerland
| | - Marianne Böni-Schnetzler
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Marc Y Donath
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland.
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Cao T, Yang D, Zhang X, Wang Y, Qiao Z, Gao L, Liang Y, Yu B, Zhang P. FAM3D inhibits glucagon secretion via MKP1-dependent suppression of ERK1/2 signaling. Cell Biol Toxicol 2017; 33:457-466. [PMID: 28247283 DOI: 10.1007/s10565-017-9387-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 02/13/2017] [Indexed: 12/28/2022]
Abstract
Dysregulated glucagon secretion is a hallmark of type 2 diabetes (T2D). To date, few effective therapeutic agents target on deranged glucagon secretion. Family with sequence similarity 3 member D (FAM3D) is a novel gut-derived cytokine-like protein, and its secretion timing is contrary to that of glucagon. However, the roles of FAM3D in metabolic disorder and its biological functions are largely unknown. In the present study, we investigated whether FAM3D modulates glucagon production in mouse pancreatic alpha TC1 clone 6 (αTC1-6) cells. Glucagon secretion, prohormone convertase 2 (PC2) activity, and mitogen-activated protein kinase (MAPK) pathway were assessed. Exogenous FAM3D inhibited glucagon secretion, PC2 activity, as well as extracellular-regulated protein kinase 1/2 (ERK1/2) signaling and induced MAPK phosphatase 1 (MKP1) expression. Moreover, knockdown of MKP1 and inhibition of ERK1/2 abolished and potentiated the inhibitory effect of FAM3D on glucagon secretion, respectively. Taken together, FAM3D inhibits glucagon secretion via MKP1-dependent suppression of ERK1/2 signaling. These results provide rationale for developing the therapeutic potential of FAM3D for dysregulated glucagon secretion and T2D.
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Affiliation(s)
- Ting Cao
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China
| | - Dan Yang
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China
| | - Xiong Zhang
- Department of Surgery, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Yueqian Wang
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China
| | - Zhengdong Qiao
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China
| | - Lili Gao
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China
| | - Yongjun Liang
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China
| | - Bo Yu
- Department of Surgery, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China.
| | - Peng Zhang
- Center for Medical Research and Innovation, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, 2800 Gongwei Road, Pudong, Shanghai, 201399, China.
- Department of Surgery, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China.
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Intestinal Incretins and the Regulation of Bone Physiology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1033:13-33. [PMID: 29101649 DOI: 10.1007/978-3-319-66653-2_2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although originally identified as modulators of nutrient absorption, the gut hormones gastric inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and glucagon-like peptide-2 (GLP-2) have also been found to play an important role in the regulation of bone turnover. These "incretin" hormones promote bone anabolism by stimulating osteoblast differentiation as well as increasing osteoblast longevity. In addition, GIP and perhaps GLP-2 attenuate the activity of osteoclastic cells, leading to a net increase in bone deposition and ultimately increasing bone mass. Studies have demonstrated that these hormones are important for bone mineralization and overall bone quality and function evolutionarily as important nutritional links signaling nutrient availability for skeletal anabolic functions. Accordingly, these entero-osseous hormones (EOH) have therapeutic potential for the management of osteoporosis. Although this chapter primarily focuses on skeletal effects of these incretin hormones, the GIP, GLP-1, and GLP-2 receptors are actually widely expressed throughout the body. Therefore, we will also briefly discuss these extraosseous receptors/effects and how they may indirectly impact the skeleton.
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46
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Fava GE, Dong EW, Wu H. Intra-islet glucagon-like peptide 1. J Diabetes Complications 2016; 30:1651-1658. [PMID: 27267264 PMCID: PMC5050074 DOI: 10.1016/j.jdiacomp.2016.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 05/14/2016] [Accepted: 05/17/2016] [Indexed: 02/06/2023]
Abstract
PURPOSE Glucagon-like peptide-1 (GLP-1) is originally identified in the gut as an incretin hormone, and it is potent in stimulating insulin secretion in the pancreas. However, increasing evidence suggests that GLP-1 is also produced locally within pancreatic islets. This review focuses on the past and current discoveries regarding intra-islet GLP-1 production and its functions. MAIN FINDINGS There has been a long-standing debate with regard to whether GLP-1 is produced in the pancreatic α cells. Early controversies lead to the widely accepted conclusion that the vast majority of proglucagon is processed to form glucagon in the pancreas, whereas an insignificant amount is cleaved to produce GLP-1. With technological advancements, recent studies have shown that bioactive GLP-1 is produced locally in the pancreas, and the expression and secretion of GLP-1 within islets are regulated by various factors such as cytokines, hyperglycemia, and β cell injury. CONCLUSIONS GLP-1 is produced by the pancreatic α cells, and it is fully functional as an incretin. Therefore, intra-islet GLP-1 may exert insulinotropic and glucagonostatic effects locally via paracrine and/or autocrine actions, under both normal and diabetic conditions.
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Affiliation(s)
- Genevieve E Fava
- Endocrinology Section, Department of Medicine, Tulane University Health Science Center, New Orleans, LA, United States
| | - Emily W Dong
- Endocrinology Section, Department of Medicine, Tulane University Health Science Center, New Orleans, LA, United States
| | - Hongju Wu
- Endocrinology Section, Department of Medicine, Tulane University Health Science Center, New Orleans, LA, United States.
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Mayo BJ, Stringer AM, Bowen JM, Bateman EH, Keefe DM. Irinotecan-induced mucositis: the interactions and potential role of GLP-2 analogues. Cancer Chemother Pharmacol 2016; 79:233-249. [PMID: 27770239 DOI: 10.1007/s00280-016-3165-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/06/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE A common side effect of irinotecan administration is gastrointestinal mucositis, often manifesting as severe diarrhoea. The damage to the structure and function of the gastrointestinal tract caused by this cytotoxic agent is debilitating and often leads to alterations in patients' regimens, hospitalisation or stoppage of treatment. The purpose of this review is to identify mechanisms of irinotecan-induced intestinal damage and a potential role for GLP-2 analogues for intervention. METHODS This is a review of current literature on irinotecan-induced mucositis and GLP-2 analogues mechanisms of action. RESULTS Recent studies have found alterations that appear to be crucial in the development of severe intestinal mucositis, including early apoptosis, alterations in proliferation and cell survival pathways, as well as induction of inflammatory cascades. Several studies have indicated a possible role for glucagon-like peptide-2 analogues in treating this toxicity, due to its proven intestinotrophic, anti-apoptotic and anti-inflammatory effects in other models of gastrointestinal disease. CONCLUSION This review provides evidence as to why and how this treatment may improve mucositis through the possible molecular crosstalk that may be occurring in models of severe intestinal mucositis.
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Affiliation(s)
- Bronwen J Mayo
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia. .,School of Pharmacy and Medical Sciences, Sansom Institute for Health Sciences, University of South Australia, Adelaide, South Australia, Australia.
| | - Andrea M Stringer
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.,School of Pharmacy and Medical Sciences, Sansom Institute for Health Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Joanne M Bowen
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Emma H Bateman
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Dorothy M Keefe
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
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Timper K, Dalmas E, Dror E, Rütti S, Thienel C, Sauter NS, Bouzakri K, Bédat B, Pattou F, Kerr-Conte J, Böni-Schnetzler M, Donath MY. Glucose-Dependent Insulinotropic Peptide Stimulates Glucagon-Like Peptide 1 Production by Pancreatic Islets via Interleukin 6, Produced by α Cells. Gastroenterology 2016; 151:165-79. [PMID: 26971825 DOI: 10.1053/j.gastro.2016.03.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 02/19/2016] [Accepted: 03/03/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Glucose-dependent insulinotropic peptide (GIP) induces production of interleukin 6 (IL6) by adipocytes. IL6 increases production of glucagon-like peptide (GLP)-1 by L cells and α cells, leading to secretion of insulin from β cells. We investigated whether GIP regulates GLP1 and glycemia via IL6. METHODS We obtained samples of human pancreatic islets and isolated islets from mice; human α cells and β cells were sorted by flow cytometry and incubated with GIP. Islets were analyzed by quantitative polymerase chain reaction and immunohistochemistry. BKS.Cg-Dock7m+/+ Leprdb/J db/db mice (diabetic mice) and db/+ mice, as well as C57BL/6J IL6-knockout mice (IL6-KO) and C57BL/6J mice with the full-length Il6 gene (controls), were fed a chow or a high-fat diet; some mice were given injections of recombinant GIP, IL6, GLP, a neutralizing antibody against IL6 (anti-IL6), lipopolysaccharide, and/or IL1B. Mice were given a glucose challenge and blood samples were collected and analyzed. RESULTS Incubation of mouse and human pancreatic α cells with GIP induced their production of IL6, leading to production of GLP1 and insulin secretion from pancreatic islets. This did not occur in islets from IL6-KO mice or in islets incubated with anti-IL6. Incubation of islets with IL1B resulted in IL6 production but directly reduced GLP1 production. Incubation of mouse islets with the sodium glucose transporter 2 inhibitor dapagliflozin induced production of GLP1 and IL6. Injection of control mice with GIP increased plasma levels of GLP1, insulin, and glucose tolerance; these effects were amplified in mice given lipopolysaccharide but reduced in IL6-KO mice or in mice given anti-IL6. Islets from diabetic mice had increased levels of IL1B and IL6, compared with db/+ mice, but injection of GIP did not lead to production of GLP1 or reduce glycemia. CONCLUSIONS In studies of pancreatic islets from human beings and mice, we found that GIP induces production of IL6 by α cells, leading to islet production of GLP1 and insulin. This process is regulated by inflammation, via IL1B, and by sodium glucose transporter 2. In diabetic mice, increased islet levels of IL6 and IL1B might increase or reduce the production of GLP1 and affect glycemia.
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Affiliation(s)
- Katharina Timper
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland.
| | - Elise Dalmas
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland
| | - Erez Dror
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland
| | - Sabine Rütti
- Department of Genetic Medicine and Development, Geneva University, Geneva, Switzerland
| | - Constanze Thienel
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland
| | - Nadine S Sauter
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland
| | - Karim Bouzakri
- Department of Genetic Medicine and Development, Geneva University, Geneva, Switzerland
| | - Benoit Bédat
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University, Hospitals and University of Geneva School of Medicine, Geneva, Switzerland
| | | | | | - Marianne Böni-Schnetzler
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland
| | - Marc Y Donath
- Clinic of Endocrinology, Diabetes and Metabolism, Department of Biomedicine, University Hospital, University of Basel, Basel, Switzerland.
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Mohan H, Gasner M, Ramesh N, Unniappan S. Ghrelin, ghrelin-O-acyl transferase, nucleobindin-2/nesfatin-1 and prohormone convertases in the pancreatic islets of Sprague Dawley rats during development. J Mol Histol 2016; 47:325-36. [DOI: 10.1007/s10735-016-9673-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 03/29/2016] [Indexed: 12/18/2022]
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D'Alessio D. Is GLP-1 a hormone: Whether and When? J Diabetes Investig 2016; 7 Suppl 1:50-5. [PMID: 27186356 PMCID: PMC4854505 DOI: 10.1111/jdi.12466] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/21/2015] [Indexed: 01/24/2023] Open
Abstract
Glucagon‐like peptide‐1 (GLP‐1) is a product of proglucagon cleavage synthesized in L cells in the intestinal mucosa, α‐cells in the pancreatic islet, and neurons in the nucleus of the solitary tract. GLP‐1 is essential for normal glucose tolerance and acts through a specific GLP‐1 receptor that is expressed by islet β‐cells as well as other cell types. Because plasma concentrations of GLP‐1 increase following meal ingestion it has been generally presumed that GLP‐1 acts as a hormone, communicating information from the intestine to the endocrine pancreas through the circulation. However, there are a number of problems with this model including low circulating concentrations of GLP‐1 in plasma, limited changes after meal ingestion and rapid metabolism in the plasma. Moreover, antagonism of systemic GLP‐1 action impairs insulin secretion in the fasting state, suggesting that the GLP‐1r is active even when plasma GLP‐1 levels are low and unchanging. Consistent with these observations, deletion of the GLP‐1r from islet β‐cells causes intolerance after IP or IV glucose, challenges that do not induce GLP‐1 secretion. Taken together, these data support a model whereby GLP‐1 acts through neural or paracrine mechanisms to regulate physiologic insulin secretion. In contrast, bariatric surgery seems to be a condition in which circulating GLP‐1 could have an endocrine effect. Both gastric bypass and sleeve gastrectomy are associated with substantial increases in postprandial GLP‐1 release and in these conditions interference with GLP‐1r signaling has a significant impact on glucose regulation after eating. Thus, with either bariatric surgery or treatment with long‐acting GLP‐1r agonists, circulating peptide mediates insulinotropic activity. Overall, a case can be made that physiologic actions of GLP‐1 are not hormonal, but that an endocrine mechanism of GLP‐1r activation can be co‐opted for therapeutics.
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Affiliation(s)
- David D'Alessio
- Division of Endocrinology, Metabolism and Nutrition Duke University Medical Center Durham North Carolina USA
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