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Li H, Liu S, Zhang K, Zhu X, Dai J, Lu Y. Gut microbiome and plasma metabolome alterations in myopic mice. Front Microbiol 2023; 14:1251243. [PMID: 38179454 PMCID: PMC10764480 DOI: 10.3389/fmicb.2023.1251243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/30/2023] [Indexed: 01/06/2024] Open
Abstract
Background Myopia is one of the most common eye diseases leading to blurred distance vision. Inflammatory diseases could trigger or exacerbate myopic changes. Although gut microbiota bacteria are associated with various inflammatory diseases, little is known about its role in myopia. Materials and methods The mice were randomly divided into control and model groups, with the model group being attached-30D lens onto the eyes for 3 weeks. Then, mouse cecal contents and plasma were collected to analyze their intestinal microbiota and plasma metabolome. Results We identified that the microbial composition differed considerably between the myopic and non-myopic mice, with the relative abundance of Firmicutes phylum decreased obviously while that of Actinobacteria phylum was increased in myopia. Furthermore, Actinobacteria and Bifidobacterium were positively correlated with axial lengths (ALs) of eyeballs while negatively correlated with refractive diopters. Untargeted metabolomic analysis identified 141 differentially expressed metabolites, and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed considerable enrichment mainly in amino acid metabolism pathways. Notably, pathways involved glutamate metabolism including "Glutamine and D-glutamate metabolism" and "Alanine, aspartate and glutamate metabolism" was changed dramatically, which presented as the concentrations of L-Glutamate and L-Glutamine decreased obviously in myopia. Interestingly, microbiome dysbiosis and metabolites alternations in myopia have a disrupting gut barrier feature. We further demonstrated that the gut barrier function was impaired in myopic mice manifesting in decreased expression of Occludin, ZO-1 and increased permeation of FITC-dextran. Discussion Myopic mice had obviously altered gut microbiome and metabolites profiles compared to non-myopic mice. The dysbiosis and plasma metabolomics shift in myopia had an interrupting gut barrier feature. Our study provides new insights into the possible role of the gut microbiota in myopia and reinforces the potential feasibility of microbiome-based therapies in myopia.
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Affiliation(s)
- Hao Li
- Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Shuyu Liu
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Keke Zhang
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Xiangjia Zhu
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jinhui Dai
- Department of Ophthalmology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yi Lu
- Eye Institute, Eye & ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Shanghai, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
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Systematic evaluation of antimicrobial food preservatives on glucose metabolism and gut microbiota in healthy mice. NPJ Sci Food 2022; 6:42. [PMID: 36100593 PMCID: PMC9470552 DOI: 10.1038/s41538-022-00158-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/31/2022] [Indexed: 11/25/2022] Open
Abstract
Certain antimicrobial preservatives (APs) have been shown to perturb gut microbiota. So far, it is not yet fully known that whether similar effects are observable for a more diverse set of APs. It also remains elusive if biogenic APs are superior to synthetic APs in terms of safety. To help fill these knowledge gaps, the effects of eleven commonly used synthetic and biogenic APs on the gut microbiota and glucose metabolism were evaluated in the wild-type healthy mice. Here, we found that APs induced glucose intolerance and perturbed gut microbiota, irrespective of their origin. In addition, biogenic APs are not always safer than synthetic ones. The biogenic AP nisin unexpectedly induced the most significant effects, which might be partially mediated by glucagon-like peptide 1 related glucoregulatory hormones secretion perturbation.
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Nauck MA, Wefers J, Meier JJ. Treatment of type 2 diabetes: challenges, hopes, and anticipated successes. Lancet Diabetes Endocrinol 2021; 9:525-544. [PMID: 34181914 DOI: 10.1016/s2213-8587(21)00113-3] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022]
Abstract
Despite the successful development of new therapies for the treatment of type 2 diabetes, such as glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter-2 inhibitors, the search for novel treatment options that can provide better glycaemic control and at reduce complications is a continuous effort. The present Review aims to present an overview of novel targets and mechanisms and focuses on glucose-lowering effects guiding this search and developments. We discuss not only novel developments of insulin therapy (eg, so-called smart insulin preparation with a glucose-dependent mode of action), but also a group of drug classes for which extensive research efforts have not been rewarded with obvious clinical impact. We discuss the potential clinical use of the salutary adipokine adiponectin and the hepatokine fibroblast growth factor (FGF) 21, among others. A GLP-1 peptide receptor agonist (semaglutide) is now available for oral absorption, and small molecules activating GLP-1 receptors appear on the horizon. Bariatric surgery and its accompanying changes in the gut hormonal milieu offer a background for unimolecular peptides interacting with two or more receptors (for GLP-1, glucose-dependent insulinotropic polypeptide, glucagon, and peptide YY) and provide more substantial glycaemic control and bodyweight reduction compared with selective GLP-1 receptor agonists. These and additional approaches will help expand the toolbox of effective medications needed for optimising the treatment of well delineated subgroups of type 2 diabetes or help develop personalised approaches for glucose-lowering drugs based on individual characteristics of our patients.
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Affiliation(s)
- Michael A Nauck
- 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
| | - Juris J Meier
- Diabetes Division, Katholisches Klinikum Bochum, St Josef Hospital, Ruhr University Bochum, Bochum, Germany
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The role of gut microbiota and amino metabolism in the effects of improvement of islet β-cell function after modified jejunoileal bypass. Sci Rep 2021; 11:4809. [PMID: 33637880 PMCID: PMC7910448 DOI: 10.1038/s41598-021-84355-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 02/15/2021] [Indexed: 12/23/2022] Open
Abstract
The change in gut microbiota is an important mechanism of the amelioration of type 2 diabetes mellitus (T2DM) after bariatric surgery. Here, we observe that the modified jejunoileal bypass effectively decreases body weight gain, fasting blood glucose, and lipids level in serum; additionally, islet β-cell function, glucose tolerance, and insulin resistance were markedly ameliorated. The hypoglycemic effect and the improvement in islet β-cell function depend on the changes in gut microbiota structure. modified jejunoileal bypass increases the abundance of gut Escherichia coli and Ruminococcus gnavus and the levels of serum glycine, histidine, and glutamine in T2DM rats; and decreases the abundance of Prevotella copri and the levels of serum branched chain amino acids, which are significantly related to the improvement of islet β-cell function in T2DM rats. Our results suggest that amino acid metabolism may contribute to the islet β-cell function in T2DM rats after modified jejunoileal bypass and that improving gut microbiota composition is a potential therapeutic strategy for T2DM.
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Evaluation of an Amino Acid Mix on the Secretion of Gastrointestinal Peptides, Glucometabolic Homeostasis, and Appetite in Obese Adolescents Administered with a Fixed-Dose or ad Libitum Meal. J Clin Med 2020; 9:jcm9093054. [PMID: 32971830 PMCID: PMC7564111 DOI: 10.3390/jcm9093054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 01/01/2023] Open
Abstract
Proteins have been demonstrated to reduce food intake in animals and humans via peripheral and central mechanisms. Supplementation of a dietetic regimen with single or mixed amino acids might represent an approach to improve the effectiveness of any body weight reduction program in obese subjects. The aim of the present study was to evaluate the effects of an amino acid mix (L-arginine + L-leucine + L-glutamine + L-tryptophan) on the secretion of some gastrointestinal peptides (i.e., ghrelin and glucagon-like peptide type 1, GLP-1), glucometabolic homeostasis (i.e., glucose, insulin, and glucagon), and appetite (hunger/satiety scored by visual analogue scale, VAS) in obese adolescents (n = 14; 10 females and 4 males; age: 16.6 ± 1.0 years; body mass index (BMI): 36.4 ± 4.6 kg/m²; fat-free mass (FFM): 54.9 ± 4.7%; fat mass (FM): 45.1 ± 4.4%) administered with a fixed-dose (lunch) or ad libitum (dinner) meal. Isocaloric maltodextrins were used as control treatment. During the lunch test, a significant increase in circulating levels of GLP-1, but not of ghrelin, was observed in the amino acid-treated group, which was congruent with significant changes in appetite, i.e., increase in satiety and decrease in hunger. A significant hyperglycemia was found in the maltodextrin-treated group during the prelunch period, without any significant changes in insulin and glucagon between the two groups. During the dinner test, there were no significant differences in appetite (hunger/satiety) and intake of calories. In conclusion, L-arginine, L-leucine, L-glutamine, and L-tryptophan, when administered to obese adolescents with a fixed-dose meal, are capable of evoking an anorexigenic response, which is, at least in part, mediated by an increase in GLP-1 released in circulation by L cells, which are capable of chemosensing specific amino acids present in the intestinal lumen. Further additional studies are requested to understand whether higher doses are necessary to inhibit ad libitum feeding.
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Petrus P, Lecoutre S, Dollet L, Wiel C, Sulen A, Gao H, Tavira B, Laurencikiene J, Rooyackers O, Checa A, Douagi I, Wheelock CE, Arner P, McCarthy M, Bergo MO, Edgar L, Choudhury RP, Aouadi M, Krook A, Rydén M. Glutamine Links Obesity to Inflammation in Human White Adipose Tissue. Cell Metab 2020; 31:375-390.e11. [PMID: 31866443 DOI: 10.1016/j.cmet.2019.11.019] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/27/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022]
Abstract
While obesity and associated metabolic complications are linked to inflammation of white adipose tissue (WAT), the causal factors remain unclear. We hypothesized that the local metabolic environment could be an important determinant. To this end, we compared metabolites released from WAT of 81 obese and non-obese women. This identified glutamine to be downregulated in obesity and inversely associated with a pernicious WAT phenotype. Glutamine administration in vitro and in vivo attenuated both pro-inflammatory gene and protein levels in adipocytes and WAT and macrophage infiltration in WAT. Metabolomic and bioenergetic analyses in human adipocytes suggested that glutamine attenuated glycolysis and reduced uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) levels. UDP-GlcNAc is the substrate for the post-translational modification O-linked β-N-acetylglucosamine (O-GlcNAc) mediated by the enzyme O-GlcNAc transferase. Functional studies in human adipocytes established a mechanistic link between reduced glutamine, O-GlcNAcylation of nuclear proteins, and a pro-inflammatory transcriptional response. Altogether, glutamine metabolism is linked to WAT inflammation in obesity.
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Affiliation(s)
- Paul Petrus
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Simon Lecoutre
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Lucile Dollet
- Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Clotilde Wiel
- Department of Biosciences and Nutrition (BioNut), H2, Karolinska Institutet, Stockholm 141 86, Sweden
| | - André Sulen
- Integrated Cardio Metabolic Centre, Department of Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Hui Gao
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Beatriz Tavira
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Jurga Laurencikiene
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Olav Rooyackers
- Perioperative Medicine and Intensive Care, B31, Karolinska University Hospital, Huddinge, 141 86 Stockholm, Sweden
| | - Antonio Checa
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Iyadh Douagi
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Craig E Wheelock
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Peter Arner
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden
| | - Mark McCarthy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Old Road, Headington, Oxford OX3 7LJ, UK; Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK; Oxford NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Martin O Bergo
- Department of Biosciences and Nutrition (BioNut), H2, Karolinska Institutet, Stockholm 141 86, Sweden
| | - Laurienne Edgar
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Robin P Choudhury
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Myriam Aouadi
- Integrated Cardio Metabolic Centre, Department of Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Anna Krook
- Department of Physiology and Pharmacology, Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Rydén
- Department of Medicine (H7), Karolinska Institutet, Stockholm 141 86, Sweden.
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Knauf C, Abot A, Wemelle E, Cani PD. Targeting the Enteric Nervous System to Treat Metabolic Disorders? "Enterosynes" as Therapeutic Gut Factors. Neuroendocrinology 2020; 110:139-146. [PMID: 31280267 DOI: 10.1159/000500602] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/28/2019] [Indexed: 11/19/2022]
Abstract
The gut-brain axis is of crucial importance for controlling glucose homeostasis. Alteration of this axis promotes the type 2 diabetes (T2D) phenotype (hyperglycaemia, insulin resistance). Recently, a new concept has emerged to demonstrate the crucial role of the enteric nervous system in the control of glycaemia via the hypothalamus. In diabetic patients and mice, modification of enteric neurons activity in the proximal part of the intestine generates a duodenal hyper-contractility that generates an aberrant message from the gut to the brain. In turn, the hypothalamus sends an aberrant efferent message that provokes a state of insulin resistance, which is characteristic of a T2D state. Targeting the enteric nervous system of the duodenum is now recognized as an innovative strategy for treatment of diabetes. By acting in the intestine, bioactive gut molecules that we called "enterosynes" can modulate the function of a specific type of neurons of the enteric nervous system to decrease the contraction of intestinal smooth muscle cells. Here, we focus on the origins of enterosynes (hormones, neurotransmitters, nutrients, microbiota, and immune factors), which could be considered therapeutic factors, and we describe their modes of action on enteric neurons. This unsuspected action of enterosynes is proposed for the treatment of T2D, but it could be applied for other therapeutic solutions that implicate communication between the gut and brain.
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Affiliation(s)
- Claude Knauf
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1220, Université Paul Sabatier, UPS, Institut de Recherche en Santé Digestive et Nutrition (IRSD), Toulouse, France,
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France,
| | - Anne Abot
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1220, Université Paul Sabatier, UPS, Institut de Recherche en Santé Digestive et Nutrition (IRSD), Toulouse, France
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France
| | - Eve Wemelle
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1220, Université Paul Sabatier, UPS, Institut de Recherche en Santé Digestive et Nutrition (IRSD), Toulouse, France
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France
| | - Patrice D Cani
- NeuroMicrobiota, European Associated Laboratory (EAL) INSERM, Toulouse, France
- UCLouvain, Université Catholique de Louvain, WELBIO - Walloon Excellence in Life Sciences and BIOtechnology, Louvain Drug Research Institute, Metabolism and Nutrition Research Group, Brussels, Belgium
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Amin A, Neophytou C, Thein S, Martin NM, Alamshah A, Spreckley E, Bloom SR, Murphy KG. L-Arginine Increases Postprandial Circulating GLP-1 and PYY Levels in Humans. Obesity (Silver Spring) 2018; 26:1721-1726. [PMID: 30358156 PMCID: PMC6220957 DOI: 10.1002/oby.22323] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/13/2018] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The satiating effect of protein compared with other nutrients has been well described and is thought to be mediated, in part, by gut hormone release. Previously, it has been shown that oral L-arginine acts as a GLP-1 secretagogue both in vitro and in vivo in rodents. Here, the effect of L-arginine on gut hormone release in humans was investigated. METHODS The hypothesis was tested in two separate studies. The first study assessed the tolerability of oral L-arginine in healthy human subjects. The second study assessed the effect of oral L-arginine on gut hormone release following an ad libitum meal. Subjects were given L-arginine, glycine (control amino acid), or vehicle control in a randomized double-blind fashion. RESULTS At a dose of 17.1 mmol, L-arginine was well tolerated and stimulated the release of plasma GLP-1 (P < 0.05) and PYY (P < 0.001) following an ad libitum meal. Food diaries showed a trend toward lower energy intake and particularly fat intake following L-arginine treatment. CONCLUSIONS L-arginine can significantly elevate GLP-1 and PYY in healthy human volunteers in combination with a meal. Further work is required to investigate whether L-arginine may have utility in the suppression of appetite and food intake.
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Affiliation(s)
- Anjali Amin
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Christina Neophytou
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Shermaine Thein
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Niamh M Martin
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Amin Alamshah
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Eleanor Spreckley
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Stephen R. Bloom
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
| | - Kevin G. Murphy
- Section of Endocrinology and Investigative Medicine, Department of MedicineImperial College LondonLondonUK
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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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Clemmensen C, Jørgensen CV, Smajilovic S, Bräuner-Osborne H. Robust GLP-1 secretion by basic L-amino acids does not require the GPRC6A receptor. Diabetes Obes Metab 2017; 19:599-603. [PMID: 27943578 DOI: 10.1111/dom.12845] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 12/05/2016] [Accepted: 12/06/2016] [Indexed: 01/15/2023]
Abstract
The G protein-coupled receptor GPRC6A (GPCR, Class C, group 6, subtype A) has been proposed to be a sensor for basic L-amino acids that are hypothesized to translate ingestive behaviour to endocrine information. However, the contribution of the GPRC6A receptor to L-amino acid-induced glucagon-like peptide 1 (GLP-1) secretion is unclear. Therefore, to discover whether the GPRC6A receptor is indispensible for amino acid-induced secretion of GLP-1, we treated, with oral gavage, GPRC6A knock-out (KO) and wild-type (WT) littermate mice with GPRC6A ligands (L-arginine and L-ornithine) and assessed GLP-1 levels in circulation. We found that oral administration of both L-arginine and L-ornithine significantly increased total plasma GLP-1 levels to a similar level in GPRC6A KO and WT mice 15 minutes after gavage (both amino acids) and accumulated up to 60 minutes after gavage (L-arginine). Conversely, GLP-1 secretion at the 30- and 60-minute time points in the KO mice was attenuated and did not reach statistical significance. In summary, these data confirm that L-arginine is a potent GLP-1 secretagogue and show that the main effect occurs independently of GPRC6A. In addition, this is the first study to show that also L-ornithine powerfully elicits GLP-1 release in vivo.
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Affiliation(s)
- Christoffer Clemmensen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, Munich, Germany
| | - Christinna V Jørgensen
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Sanela Smajilovic
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Hans Bräuner-Osborne
- Faculty of Health and Medical Sciences, Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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