1
|
Fu Y, Ji W, Liu Q, Zhang L, Li C, Huan Y, Lei L, Gao X, Chen L, Feng C, Lei L, Zhai J, Li P, Cao H, Liu S, Shen Z. Voglibose Regulates the Secretion of GLP-1 Accompanied by Amelioration of Ileal Inflammatory Damage and Endoplasmic Reticulum Stress in Diabetic KKAy Mice. Int J Mol Sci 2022; 23:ijms232415938. [PMID: 36555580 PMCID: PMC9786790 DOI: 10.3390/ijms232415938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/04/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
Voglibose is an α-glycosidase inhibitor that improves postprandial hyperglycemia and increases glucagon-like peptide-1 (GLP-1) secretion in patients with type 2 diabetes. Recently, there has been increasing interest in the anti-inflammatory effects of voglibose on the intestine, but the underlying mechanism is not clear. This study evaluated the effects and mechanisms of voglibose on glycemic control and intestinal inflammation. Type 2 diabetic KKAy mice were treated with voglibose (1 mg/kg) by oral gavage once daily. After 8 weeks, glucose metabolism, levels of short-chain fatty acids (SCFAs), systematic inflammatory factors, intestinal integrity and inflammation were evaluated using hematoxylin and eosin staining, immunohistochemistry, immunofluorescence and Western blot analysis. Voglibose ameliorated glucose metabolism by enhancing basal- and glucose-dependent GLP-1 secretion. Several beneficial SCFAs, such as acetic acid and propionic acid, were increased by voglibose in the fecal sample. Additionally, voglibose notably decreased the proportion of pro-inflammatory macrophages and the expression of nuclear factor kappa B but increased the expression of tight junction proteins in the ileum, thus markedly improving intestinal inflammatory damage and reducing the systematic inflammatory factors. Ileal genomics and protein validation suggested that voglibose attenuated inositol-requiring protein 1α-X-box binding protein 1-mediated endoplasmic reticulum stress (ERS). Together, these results showed that voglibose enhanced the secretion of GLP-1, which contributed to the glycemic control in KKAy mice at least in part by regulating intestinal inflammation and the expression of ERS factors.
Collapse
Affiliation(s)
- Yaxin Fu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Wenming Ji
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Quan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Lin Zhang
- Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
- Department of Medical Records, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
- Beijing Diabetes Institute, Beijing 100730, China
| | - Caina Li
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yi Huan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Lei Lei
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xuefeng Gao
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Leilei Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Cunyu Feng
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Liran Lei
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Jiayu Zhai
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Pingping Li
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Hui Cao
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Correspondence: (H.C.); (S.L.)
| | - Shuainan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Diabetes Research Center of Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Correspondence: (H.C.); (S.L.)
| | - Zhufang Shen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
- Key Laboratory of Polymorphic Drugs of Beijing, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| |
Collapse
|
2
|
Martchenko A, Biancolin AD, Martchenko SE, Brubaker PL. Nobiletin ameliorates high fat-induced disruptions in rhythmic glucagon-like peptide-1 secretion. Sci Rep 2022; 12:7271. [PMID: 35508494 PMCID: PMC9068808 DOI: 10.1038/s41598-022-11223-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/20/2022] [Indexed: 02/06/2023] Open
Abstract
The incretin hormone glucagon-like peptide-1 (GLP-1) is secreted by the intestinal L cell in response to nutrient intake. However, GLP-1 secretion also follows a circadian rhythm which is disrupted by the saturated fatty acid palmitate in vitro and high-fat diet (HFD) feeding in vivo. The flavonoid nobiletin is a clock enhancer which improves metabolic homeostasis. Therefore, the aim of this study was to elucidate whether and how nobiletin mitigates the negative effects of palmitate and HFD-feeding on rhythmic GLP-1 release. Pre-treatment of murine GLUTag L cells with palmitate dampened the GLP-1 secretory response at the normal peak of secretion, while nobiletin co-treatment restored GLP-1 secretion and upregulated the ‘metabolic pathway’ transcriptome. Mice fed a HFD also lost their GLP-1 secretory rhythm in association with markedly increased GLP-1 levels and upregulation of L cell transcriptional pathways related to ‘sensing’ and ‘transducing’ cellular stimuli at the normal peak of GLP-1 release. Nobiletin co-administration reduced GLP-1 levels to more physiological levels and upregulated L cell ‘oxidative metabolism’ transcriptional pathways. Furthermore, nobiletin improved colonic microbial 16S rRNA gene diversity and reduced the levels of Proteobacteria in HFD-fed mice. Collectively, this study establishes that nobiletin improves the normal rhythm in GLP-1 secretion following fat-induced disruption.
Collapse
Affiliation(s)
- Alexandre Martchenko
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Andrew D Biancolin
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Sarah E Martchenko
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Patricia L Brubaker
- Department of Physiology, University of Toronto, Rm 3366 Medical Sciences Building, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. .,Department of Medicine, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
3
|
The Regulatory Role of Neuropeptide Gene Glucagon in Colorectal Cancer: A Comprehensive Bioinformatic Analysis. DISEASE MARKERS 2022; 2022:4262600. [PMID: 35340411 PMCID: PMC8956438 DOI: 10.1155/2022/4262600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/05/2022] [Accepted: 01/08/2022] [Indexed: 11/26/2022]
Abstract
Background Colorectal cancer is highly prevalent and causes high global mortality, and glucagon axis has been implicated in colon cancer. The present study is aimed at investigating the regulating mechanisms of glucagon involvement in colorectal cancer. Methods Publicly available data from the TCGA database was utilized to explore the expression pattern and regulating role of glucagon (GCG) in colorectal cancer (COADREAD) including colon adenocarcinomas (COAD) and rectum adenocarcinomas (READ). Statistical analyses were performed using the R software packages and public web servers. The expression pattern and prognostic significance of GCG gene in pan-cancer and TCGA-COADREAD data were investigated by performing unpaired and paired sample analyses. The association of GCG expression with clinical characteristics was investigated using logistic regression analysis. Univariate cox regression analysis was performed to test the prognostic value of GCG expression for overall survival in COADREAD patients. GCG-significantly correlated genes were obtained. Biological functions and signaling pathways were identified by performing functional enrichment analysis and Gene Set Enrichment Analysis (GSEA). Additionally, the potential involvement of GCG in tumor immunity was researched by investigating the correlation between GCG expression and 24 tumor infiltrating immune cells. Results GCG was found to be significantly downregulated in COADREAD tumor samples compared with healthy control samples. GCG gene was shown to be associated with the prognostic outcomes of COADREAD, whereby its upregulation predicted improved survival outcomes. Functional enrichment analysis showed that the top 100 positively and top 100 negatively GCG-correlated genes were mainly enriched in three signaling pathways including ribosome, nitrogen metabolism, and proximal tubule bicarbonate reclamation. The GSEA showed that GCG-significantly correlated genes were mainly enriched in cell cycle-related pathways (reactome cell cycle, reactome cell cycle mitotic, reactome cell cycle checkpoints, reactome M phase, Reactome G2 M DNA damage checkpoint, and Reactome G2 M checkpoints), neuropeptide ligand receptor interaction, RHO GTPases signaling, WNT signaling, RUNX1 signaling, NOTCH signaling, ESR signaling, HCMV infection, and oxidative stress-related signaling. GCG was positively correlated with Th17 cells, pDC, macrophages, TFH cells, iDC, Tem, B cells, dendritic cells, neutrophils, mast cells, and eosinophils and was negatively associated with NK cells. Conclusions GCG dysregulation with high prognostic value in COADREAD was noted. Several tumor progression-related pathways and tumor immune-modulatory cells were linked to GCG expression in COADREAD. Therefore, GCG may be regarded as a potential therapeutic target for treating colorectal cancer.
Collapse
|
4
|
Liu C, Liu Y, Xin Y, Wang Y. Circadian secretion rhythm of GLP-1 and its influencing factors. Front Endocrinol (Lausanne) 2022; 13:991397. [PMID: 36531506 PMCID: PMC9755352 DOI: 10.3389/fendo.2022.991397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 11/22/2022] [Indexed: 12/04/2022] Open
Abstract
Circadian rhythm is an inherent endogenous biological rhythm in living organisms. However, with the improvement of modern living standards, many factors such as prolonged artificial lighting, sedentarism, short sleep duration, intestinal flora and high-calorie food intake have disturbed circadian rhythm regulation on various metabolic processes, including GLP-1 secretion, which plays an essential role in the development of various metabolic diseases. Herein, we focused on GLP-1 and its circadian rhythm to explore the factors affecting GLP-1 circadian rhythm and its potential mechanisms and propose some feasible suggestions to improve GLP-1 secretion.
Collapse
|
5
|
Martchenko A, Brubaker PL. Effects of Obesogenic Feeding and Free Fatty Acids on Circadian Secretion of Metabolic Hormones: Implications for the Development of Type 2 Diabetes. Cells 2021; 10:cells10092297. [PMID: 34571945 PMCID: PMC8466112 DOI: 10.3390/cells10092297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 11/19/2022] Open
Abstract
Circadian rhythms are 24-h internal biological rhythms within organisms that govern virtually all aspects of physiology. Interestingly, metabolic tissues have been found to express cell-autonomous clocks that govern their rhythmic activity throughout the day. Disruption of normal circadian rhythmicity, as induced by environmental factors such as shift work, significantly increases the risk for the development of metabolic diseases, including type 2 diabetes and obesity. More recently, obesogenic feeding and its fatty acid components have also been shown to be potent disruptors of normal circadian biology. Two key hormones that are released in response to nutrient intake are the anti-diabetic incretin hormone glucagon-like peptide-1, from intestinal L cells, and insulin secreted by pancreatic β cells, both of which are required for the maintenance of metabolic homeostasis. This review will focus on the circadian function of the L and β cells and how both obesogenic feeding and the saturated fatty acid, palmitate, affect their circadian clock and function. Following introduction of the core biological clock and the hierarchical organization of the mammalian circadian system, the circadian regulation of normal L and β cell function and the importance of GLP-1 and insulin in establishing metabolic control are discussed. The central focus of the review then considers the circadian-disrupting effects of obesogenic feeding and palmitate exposure in L and β cells, while providing insight into the potential causative role in the development of metabolic disease.
Collapse
Affiliation(s)
| | - Patricia Lee Brubaker
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada;
- Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
- Correspondence:
| |
Collapse
|
6
|
MicroRNA-194: a novel regulator of glucagon-like peptide-1 synthesis in intestinal L cells. Cell Death Dis 2021; 12:113. [PMID: 33479193 PMCID: PMC7820456 DOI: 10.1038/s41419-020-03366-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/18/2020] [Accepted: 10/09/2020] [Indexed: 12/24/2022]
Abstract
In the status of obesity, the glucagon-like peptide-1 (GLP-1) level usually declines and results in metabolic syndrome. This study aimed to investigate the intracellular mechanism of GLP-1 synthesis in L cells from the perspective of microRNA (miRNA). In the present study, we found that GLP-1 level was down-regulated in the plasma and ileum tissues of obese mice, while the ileac miR-194 expression was up-regulated. In vitro experiments indicated that miR-194 overexpression down-regulated GLP-1 level, mRNA levels of proglucagon gene (gcg) and prohormone convertase 1/3 gene (pcsk1), and the nuclear protein level of beta-catenin (β-catenin). Further investigation confirmed that β-catenin could promote gcg transcription through binding to transcription factor 7-like 2 (TCF7L2). miR-194 suppressed gcg mRNA level via negatively regulating TCF7L2 expression. What’s more, forkhead box a1 (Foxa1) could bind to the promoter of pcsk1 and enhanced its transcription. miR-194 suppressed pcsk1 transcription through targeting Foxa1. Besides, the interference of miR-194 reduced palmitate (PA)-induced cell apoptosis and the anti-apoptosis effect of miR-194 inhibitor was abolished by TCF7L2 knockdown. Finally, in HFD-induced obese mice, the silence of miR-194 significantly elevated GLP-1 level and improved the metabolic symptoms caused by GLP-1 deficiency. To sum up, our study found that miR-194 suppressed GLP-1 synthesis in L cells via inhibiting TCF7L2-mediated gcg transcription and Foxa1-mediated pcsk1 transcription. Meanwhile, miR-194 took part in the PA-induced apoptosis of L cells.
Collapse
|
7
|
Nguyen-Tu MS, Martinez-Sanchez A, Leclerc I, Rutter GA, da Silva Xavier G. Adipocyte-specific deletion of Tcf7l2 induces dysregulated lipid metabolism and impairs glucose tolerance in mice. Diabetologia 2021; 64:129-141. [PMID: 33068125 PMCID: PMC7567653 DOI: 10.1007/s00125-020-05292-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Transcription factor 7-like 2 (TCF7L2) is a downstream effector of the Wnt/β-catenin signalling pathway implicated in type 2 diabetes risk through genome-wide association studies. Although its expression is critical for adipocyte development, the potential roles of changes in adipose tissue TCF7L2 levels in diabetes risk are poorly defined. Here, we investigated whether forced changes in Tcf7l2 expression in adipocytes affect whole body glucose or lipid metabolism and crosstalk between disease-relevant tissues. METHODS Tcf7l2 was selectively ablated in mature adipocytes in C57BL/6J mice using Cre recombinase under Adipoq promoter control to recombine Tcf7l2 alleles floxed at exon 1 (referred to as aTCF7L2 mice). aTCF7L2 mice were fed normal chow or a high-fat diet for 12 weeks. Glucose and insulin sensitivity, as well as beta cell function, were assessed in vivo and in vitro. Levels of circulating NEFA, selected hormones and adipokines were measured using standard assays. RESULTS Reduced TCF7L2 expression in adipocytes altered glucose tolerance and insulin secretion in male but not in female mice. Thus, on a normal chow diet, male heterozygote knockout mice (aTCF7L2het) exhibited impaired glucose tolerance at 16 weeks (p = 0.03) and increased fat mass (1.4 ± 0.1-fold, p = 0.007) but no changes in insulin secretion. In contrast, male homozygote knockout (aTCF7L2hom) mice displayed normal body weight but impaired oral glucose tolerance at 16 weeks (p = 0.0001). These changes were mechanistically associated with impaired in vitro glucose-stimulated insulin secretion (decreased 0.5 ± 0.1-fold vs control mice, p = 0.02) and decreased levels of the incretins glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (0.6 ± 0.1-fold and 0.4 ± 0.1-fold vs control mice, p = 0.04 and p < 0.0001, respectively). Circulating levels of plasma NEFA and fatty acid binding protein 4 were increased by 1.3 ± 0.1-fold and 1.8 ± 0.3-fold vs control mice (p = 0.03 and p = 0.05, respectively). Following exposure to a high-fat diet for 12 weeks, male aTCF7L2hom mice exhibited reduced in vivo glucose-stimulated insulin secretion (0.5 ± 0.1-fold vs control mice, p = 0.02). CONCLUSIONS/INTERPRETATION Loss of Tcf7l2 gene expression selectively in adipocytes leads to a sexually dimorphic phenotype, with impairments not only in adipocytes, but also in pancreatic islet and enteroendocrine cells in male mice only. Our findings suggest novel roles for adipokines and incretins in the effects of diabetes-associated variants in TCF7L2, and further illuminate the roles of TCF7L2 in glucose homeostasis and diabetes risk. Graphical abstract.
Collapse
Affiliation(s)
- Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
| | - Gabriela da Silva Xavier
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK.
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.
| |
Collapse
|
8
|
Wang J, Zhang X, Zhang L, Yan T, Wu B, Xu F, Jia Y. Silychristin A activates Nrf2-HO-1/SOD2 pathway to reduce apoptosis and improve GLP-1 production through upregulation of estrogen receptor α in GLUTag cells. Eur J Pharmacol 2020; 881:173236. [PMID: 32497626 DOI: 10.1016/j.ejphar.2020.173236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/21/2020] [Accepted: 05/29/2020] [Indexed: 01/08/2023]
Abstract
Glucagon-like peptide-1 (GLP-1), a glucagon-like peptide secreted mainly from intestinal L cells, possesses the functions of promoting synthesis and secretion of insulin in pancreatic β-cells, and maintaining glucose homeostasis in an insulin-independent manner. Silychristin A, a major flavonolignan from silymarin, was reported to protect pancreatic β-cells from oxidative damage in streptozotocin (STZ)-induced diabetic rats. However, the role of silychristin A in the protection of intestinal L-cells is still unknown. Our current study demonstrated that palmitate (PA) inhibited protein expression of NF-E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and superoxide dismutase 2 (SOD2), and subsequently increased reactive oxygen species level to induce apoptosis and decrease GLP-1 content in intestinal L-cell line GLUTag cells. Pre-incubation of silychristin A effectively reversed PA-inactivated Nrf2-HO-1/SOD2 antioxidative pathway accompanied with decreased apoptosis level and increased GLP-1 level in GLUTag cells. As a potential target of silychristin A, estrogen receptor α was shown to be downregulated by PA stimulation, and the expression of which was improved by silychristin A in a concentration-dependent manner. Further study revealed that the treatment of estrogen receptor α antagonist MPP induced apoptosis and blocked the stimulation of GLP-1 production by silychristin A through the activation of Nrf2-HO-1/SOD2 pathway in GLUTag cells. Taken together, our study found silychristin A activated estrogen receptor α-dependent Nrf2-HO-1/SOD2 pathway to decrease apoptosis and upregulate GLP-1 production in GLUTag cells.
Collapse
Affiliation(s)
- Jinyu Wang
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, PR China
| | - Xiaoying Zhang
- School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, PR China
| | - Luxin Zhang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, PR China
| | - Tingxu Yan
- Faculty of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, 110016, PR China
| | - Bo Wu
- Faculty of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, 110016, PR China
| | - Fanxing Xu
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, 110016, PR China.
| | - Ying Jia
- Faculty of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, 110016, PR China.
| |
Collapse
|
9
|
Sharma D, Kumar Tekade R, Kalia K. Kaempferol in ameliorating diabetes-induced fibrosis and renal damage: An in vitro and in vivo study in diabetic nephropathy mice model. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2020; 76:153235. [PMID: 32563017 DOI: 10.1016/j.phymed.2020.153235] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/03/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Kaempferol is a natural polyflavonol that has gained considerable attention as antidiabetic therapeutics. Recent reports emphasize the role of hyperglycemia and RhoA/Rho Kinase activity in the pathogenesis of diabetic nephropathy (DN). This study aims to evaluate the GLP-1 and insulin release along with RhoA/Rho Kinase inhibition pertaining to the anti-fibrotic and reno-protective effects of Kaempferol in DN. METHODS The effect of Kaempferol on GLP-1 and insulin release along with underlying mechanisms (Ca2+ and cAMP levels) in GLUTag and MIN6 cells as well as in their co-culture has been evaluated. Further, the effect of Kaempferol on GLP-1 and insulin release was evaluated under in-vivo circumstances in the DN C57BL/6 mouse model. Histology and fibrosis specific staining was performed to study the renal injuries and fibrosis, while the expression of mRNA and protein of interest was evaluated by RT-PCR and western blot analysis. RESULTS Kaempferol treatment promoted the GLP-1 and insulin release, which was accompanied by increased intracellular levels of cAMP and Ca2+ in GLUTag and MIN6 cells. In agreement with in vitro studies, Kaempferol also increased the release of GLP-1 and insulin in the DN mouse model. Notably, Kaempferol showed the potential to ameliorate the histological changes as well as renal fibrosis while decreasing the expression levels of DN markers including TGF-β1, CTGF, fibronectin, collagen IV, IL-1β, RhoA, ROCK2, and p-MYPT1 in DN kidney tissues. A rise in the expression of E-cadherin and nephrin was also noted in the same study. CONCLUSION This study establishes that Kaempferol ameliorates renal injury and fibrosis by enhancing the release of GLP-1, insulin, and inhibition of RhoA/Rho Kinase. This study recommends Kaempferol for further clinical trials to be developed as novel therapeutics for improving the renal function in DN patients.
Collapse
Affiliation(s)
- Dilip Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, 382355, Gujarat, India
| | - Rakesh Kumar Tekade
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, 382355, Gujarat, India
| | - Kiran Kalia
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, 382355, Gujarat, India; Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, 382355, Gujarat, India.
| |
Collapse
|
10
|
Handgraaf S, Dusaulcy R, Visentin F, Philippe J, Gosmain Y. Let-7e-5p Regulates GLP-1 Content and Basal Release From Enteroendocrine L Cells From DIO Male Mice. Endocrinology 2020; 161:5697307. [PMID: 31905402 DOI: 10.1210/endocr/bqz037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 01/02/2020] [Indexed: 12/30/2022]
Abstract
Characterization of enteroendocrine L cells in diabetes is critical for better understanding of the role of glucagon-like peptide-1 (GLP-1) in physiology and diabetes. We studied L-cell transcriptome changes including microRNA (miRNA) dysregulation in obesity and diabetes. We evaluated the regulation of miRNAs through microarray analyses on sorted enteroendocrine L cells from control and obese glucose-intolerant (I-HFD) and hyperglycemic (H-HFD) mice after 16 weeks of respectively low-fat diet (LFD) or high-fat diet (HFD) feeding. The identified altered miRNAs were studied in vitro using the mouse GLUTag cell line to investigate their regulation and potential biological functions. We identified that let-7e-5p, miR-126a-3p, and miR-125a-5p were differentially regulated in L cells of obese HFD mice compared with control LFD mice. While downregulation of let-7e-5p expression was observed in both I-HFD and H-HFD mice, levels of miR-126a-3p increased and of miR-125a-5p decreased significantly only in I-HFD mice compared with controls. Using miRNA inhibitors and mimics we observed that modulation of let-7e-5p expression affected specifically GLP-1 cellular content and basal release, whereas Gcg gene expression and acute GLP-1 secretion and cell proliferation were not affected. In addition, palmitate treatment resulted in a decrease of let-7e-5p expression along with an increase in GLP-1 content and release, suggesting that palmitate acts on GLP-1 through let-7e-5p. By contrast, modulation of miR-125a-5p and miR-126a-3p in the same conditions did not affect content or secretion of GLP-1. We conclude that decrease of let-7e-5p expression in response to palmitate may constitute a compensatory mechanism contributing to maintaining constant glycemia in obese mice.
Collapse
Affiliation(s)
- Sandra Handgraaf
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Rodolphe Dusaulcy
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Florian Visentin
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Jacques Philippe
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| | - Yvan Gosmain
- Molecular Diabetes Laboratory, Division of Endocrinology, Diabetes, Hypertension and Nutrition, University Hospital/Diabetes Center/University of Geneva Medical School, Geneva, Switzerland
| |
Collapse
|
11
|
Chu D, He Y, Li N, Zhang H, Zhang H, Li C, Deng Z, Chen Y, Han X, Li Y, Wei T. Immunohistochemical distribution of glucagon-like peptide 1 in the digestive system of different aquatic vertebrates. Anat Histol Embryol 2019; 49:31-37. [PMID: 31571240 DOI: 10.1111/ahe.12479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/17/2019] [Accepted: 07/22/2019] [Indexed: 11/30/2022]
Abstract
The distribution of glucagon-like peptide 1 (GLP-1)-positive cells in digestive tracts and pancreases of aquatic vertebrates was investigated by immunohistochemical staining method. The results suggested that GLP-1-positive cells were distributed in the columnar mucous epithelium and tubular glands of lamina propria in the digestive system. However, GLP-1-positive cells were also found in subepithelial lamina propria of the mucosae and muscularis in each segment of the digestive tract of Rana nigromaculata. The distribution densities of these cells reached peaks in the stomachs, and the middle or end segments of small intestines of Chinese softshell turtle, Bufo gargarizans, R. nigromaculata and catfish, and there was the third distribution density peak in the rectum of catfish. The total amount or overall density of GLP-1-positive cells varied a lot in the digestive tracts of different animal species. The distribution density was relatively low in the digestive tract of chub and reached the maximum in the digestive tracts of snakehead and catfish, but no GLP-1-positive cells were found in the digestive tract of bighead carp. GLP-1-positive cells were densely distributed in the pancreases of Chinese softshell turtle, B. gargarizans and R. nigromaculata. These cells spread over the superficial layers of islets or scattered in exocrine pancreas in the pancreas of B. gargarizans, spread in the endocrine cells or scattered in the pancreas of Chinese softshell turtle, scattered in the pancreas of R. nigromaculata and distributed in the superficial layers of islets in the pancreas of catfish.
Collapse
Affiliation(s)
- Dechang Chu
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Ying He
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Na Li
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Haili Zhang
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Hongmei Zhang
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Chunhua Li
- Logistics Management Office, Heze University, Heze, China
| | - Zhenxu Deng
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Yan Chen
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Xue Han
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Yangui Li
- College of Agriculture and Bioengineering, Heze University, Heze, China
| | - Tao Wei
- College of Agriculture and Bioengineering, Heze University, Heze, China
| |
Collapse
|
12
|
Guo Q, Hu H, Liu X, Yang D, Yin Y, Zhang B, He H, Oh Y, Wu Q, Liu C, Gu N. C/EBPβ mediates palmitate-induced musclin expression via the regulation of PERK/ATF4 pathways in myotubes. Am J Physiol Endocrinol Metab 2019; 316:E1081-E1092. [PMID: 30964708 DOI: 10.1152/ajpendo.00478.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Musclin is a muscle-secreted cytokine that disrupts glucose uptake and glycogen synthesis in type 2 diabetes. The purpose of this study was to investigate the mechanisms responsible for the regulation of musclin gene expression in response to treatment with palmitate. RNA sequencing results showed that biological processes activated by palmitate are mainly enriched in endoplasmic reticulum (ER) stress. The protein kinase RNA-like ER kinase (PERK) signaling pathway is involved in the regulation of musclin expression induced by palmitate. Chromatin immunoprecipitation data showed that activating transcription factor 4 (ATF4)-downstream of PERK-bound to the promoter of the C/EBPβ gene. Notably, C/EBPβ also contains a binding site in the region -94~-52 of the musclin gene promoter. Knockdown or knockout of PERK and ATF4 using short hairpin RNA or CRISPR-Cas9 decreased the expression of C/EBPβ and musclin induced by palmitate. Furthermore, knockdown and knockout of C/EBPβ alleviated the high expression of musclin in response to treatment with palmitate. Moreover, CRISPR-Cas9 knockout of the region -94~-52 in which C/EBPβ binds to the promoter of musclin abrogated the induction of high musclin expression caused by palmitate. Collectively, these findings suggest that treatment with palmitate activates the PERK/ATF4 signaling pathway, which in turn increases the expression of C/EBPβ. C/EBPβ binds directly to the promoter of the musclin gene and upregulates its expression.
Collapse
Affiliation(s)
- Qian Guo
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Hailong Hu
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Xiaohuan Liu
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - DaQian Yang
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Yao Yin
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Boya Zhang
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Hongjuan He
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Yuri Oh
- Faculty of Education, Wakayama University , Wakayama , Japan
| | - Qiong Wu
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Chuanpeng Liu
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| | - Ning Gu
- School of Life Science and Technology, Harbin Institute of Technology , Harbin , China
| |
Collapse
|
13
|
Ntika S, Thombare K, Aryapoor M, Kristinsson H, Bergsten P, Krizhanovskii C. Oleate increase neutral lipid accumulation, cellular respiration and rescues palmitate-exposed GLP-1 secreting cells by reducing ceramide-induced ROS. Biochimie 2019; 159:23-35. [DOI: 10.1016/j.biochi.2018.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 11/28/2018] [Indexed: 12/13/2022]
|
14
|
Wang Y, Zhang HW, Guo YL, Zhu CG, Wu NQ, Li JJ. Free fatty acids as a marker for predicting periprocedural myocardial injury after coronary intervention. Postgrad Med J 2019; 95:18-22. [PMID: 30700582 DOI: 10.1136/postgradmedj-2018-136137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 12/19/2018] [Accepted: 01/03/2019] [Indexed: 01/10/2023]
Abstract
BACKGROUND Previous studies have revealed that plasma levels of free fatty acids (FFAs) are related to cardiovascular risk. However, whether FFAs could predict periprocedural myocardial injury (PMI) following percutaneous coronary intervention (PCI) in patients with stable coronary artery disease (CAD) remains unclear. PURPOSE This study aimed to investigate the relationship of FFAs to PMI in untreated patients with CAD who underwent PCI. METHODS A total of 374 consecutive patients with CAD without lipid-lowering treatment on admission and with normal preprocedural cardiac troponin I (cTnI) levels who underwent PCI were prospectively enrolled. The baseline characteristics were collected and PMI was evaluated by cTnI analysis within 24 hours. The relation of preprocedural FFA levels to peak cTnI values after PCI was examined. RESULTS Preprocedural FFAs were positively correlated with peak cTnI values after PCI in both simple regression model (β=0.119, p=0.021) and multiple regression model (β=0.198, p=0.001). Patients with higher FFA levels had higher postprocedural cTnI levels compared with those with normal FFA levels (0.27±0.68 ng/mL vs 0.66±0.31 ng/mL, p=0.014). In the multivariable model, preprocedural FFA levels were associated with an increased risk of postprocedural cTnI elevation above 1× upper limit of normal (ULN, OR: 1.185, 95% CI 0.997 to 1.223, p=0.019) up to 10× ULN (OR: 1.132, 95% CI 1.005 to 1.192, p=0.003) . CONCLUSIONS The present study first suggested that elevated FFA levels were associated with an increased risk of PMI in untreated patients with CAD. Further study with large sample size may be needed to confirm our findings.
Collapse
Affiliation(s)
- Yu Wang
- Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Wen Zhang
- Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuan-Lin Guo
- Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Cheng-Gang Zhu
- Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Na-Qiong Wu
- Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jian-Jun Li
- Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| |
Collapse
|
15
|
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.
Collapse
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.
| |
Collapse
|
16
|
Sun Y, Jin C, Zhang X, Jia W, Le J, Ye J. Restoration of GLP-1 secretion by Berberine is associated with protection of colon enterocytes from mitochondrial overheating in diet-induced obese mice. Nutr Diabetes 2018; 8:53. [PMID: 30250193 PMCID: PMC6155143 DOI: 10.1038/s41387-018-0061-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 07/16/2018] [Accepted: 07/31/2018] [Indexed: 02/07/2023] Open
Abstract
Objective L-cell dysfunction is reported for GLP-1 reduction in type 2 diabetes. However, the mechanism of dysfunction remains unknown. In this study, we examined mitochondrial function in the mechanistic study in diet-induced obese (DIO) mice. Subjects C57BL/6 mice were fed a high-fat diet (HFD) for 16 weeks to establish the DIO model for GLP-1 reduction. The mice were then treated with berberine (BBR) (100 mg/kg/day) for 8 weeks to test the impact on GLP-1 expression. Mitochondrial activities of the colon enterocytes were compared among three groups of mice (lean, DIO, and DIO + BBR) at the end of treatment. Gut microbiota and short-chain fatty acids (SCFAs) were examined to understand the mitochondrial responses. A cellular model treated with palmitic acid (PA) was used in the mechanism study. Results A reduction in GLP-1 expression was observed in DIO mice with mitochondrial stress responses in the colon enterocytes. The mitochondria exhibited cristae loss, membrane rupture, and mitochondrial swelling, which was observed with an increase in ATP abundance, complex I activity, and deficiency in the activities of complexes II and IV. Those changes were associated with dysbiosis and a reduction in SCFAs in the colon of DIO mice. In the cellular model, an increase in ATP abundance, loss of mitochondrial potential, and elevation of apoptosis were induced by PA. All of the alterations in DIO mice and the cellular model were attenuated by BBR. Conclusion The mitochondrial stress responses were observed in the colon enterocytes of DIO mice for GLP-1 reduction. The stress was prevented by BBR in the restoration of GLP-1 expression, in which BBR may act through direct and indirect mechanisms.
Collapse
Affiliation(s)
- Yongning Sun
- Department of Traditional Chinese Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Chenxi Jin
- Queen Mary School, Nanchang University, Nanchang City, Jiangxi Province, 330031, China
| | - Xiaoying Zhang
- Central Laboratory, Shanghai Jiao Tong University Affiliated Sixth People's Hospital East, Shanghai, 201306, China
| | - Weiping Jia
- Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Jiamei Le
- Department of Traditional Chinese Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China.
| | - Jianping Ye
- Central Laboratory, Shanghai Jiao Tong University Affiliated Sixth People's Hospital East, Shanghai, 201306, China. .,Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China. .,Antioxidant and Gene Regulation Laboratory, Pennington Biomedical Research Center, LSU, Baton Rouge, LA, 70808, USA.
| |
Collapse
|
17
|
Martchenko A, Oh RH, Wheeler SE, Gurges P, Chalmers JA, Brubaker PL. Suppression of circadian secretion of glucagon-like peptide-1 by the saturated fatty acid, palmitate. Acta Physiol (Oxf) 2018; 222:e13007. [PMID: 29193800 DOI: 10.1111/apha.13007] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 11/22/2017] [Accepted: 11/23/2017] [Indexed: 12/12/2022]
Abstract
AIM Glucagon-like peptide-1 is an incretin hormone secreted by the intestinal L-cell with a circadian rhythm that parallels expression of the core clock gene, Bmal1. Although feeding rats a high-fat/high-sucrose Western diet impairs rhythmic glucagon-like peptide-1 release, the mechanisms underlying this effect remain unclear. Therefore, the aim of this study was to determine the pathway(s) by which the saturated fat, palmitate, a major component of the Western diet, impairs circadian glucagon-like peptide-1 secretion. METHODS Murine mGLUTag L-cells were synchronized, and the effects of palmitate pre-treatment on gene expression and glucagon-like peptide-1 secretion were determined, in addition to metabolite quantification, mitochondrial function analysis and enzyme inhibition and activation assays. Glucagon-like peptide-1 secretion was also analysed in ileal crypt cultures from control and Bmal1 knockout mice. RESULTS Pre-treatment with palmitate dampened Bmal1 mRNA and protein expression and glucagon-like peptide-1 secretion at 8 but not 20 hours after cell synchronization (P < .05-.001). Glucagon-like peptide-1 release was also impaired in Bmal1 knockout cultures as compared to wild-type controls (P < .001). Palmitate pre-treatment reduced expression of the Bmal1 downstream target, nicotinamide phosphoribosyltransferase, the rate-limiting enzyme in the synthesis of NAD+ . This was paralleled by dampening of total NAD+ levels, as well as impaired mitochondrial function and ATP production (P < .05-.001). Whereas direct inhibition of nicotinamide phosphoribosyltransferase also decreased glucagon-like peptide-1 release, activation of this enzyme restored glucagon-like peptide-1 secretion in the presence of palmitate. CONCLUSION Palmitate impairs L-cell clock function at the peak of Bmal1 gene expression, thereby impairing mitochondrial function and ultimately rhythmic glucagon-like peptide-1 secretion.
Collapse
Affiliation(s)
- A Martchenko
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - R H Oh
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - S E Wheeler
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - P Gurges
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - J A Chalmers
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - P L Brubaker
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
18
|
Wang X, Liu J, Li C, Zhao M, Liu L, Guan Q, Zhang H, Zhang X, Gao L, Zhao J, Song Y. Impaired secretion of active GLP-1 in patients with hypertriglyceridaemia: A novel lipotoxicity paradigm? Diabetes Metab Res Rev 2018; 34. [PMID: 29135069 DOI: 10.1002/dmrr.2964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/31/2017] [Accepted: 11/05/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND Lipotoxicity plays an important role in the pathogenesis of β-cell dysfunction. Glucagon-like peptide-1 (GLP-1) is an incretin hormone that exerts beneficial effects on the number and function of islet β cells. However, the effect of lipotoxicity on GLP-1 secretion is still unknown. METHODS Twenty-five patients who were newly diagnosed with diabetes were recruited from 400 subjects based on 75-g Oral Glucose Tolerance Test. Patients were divided into diabetes (DM) and DM combined with hypertriglyceridaemia (DM + HTG) groups according to their serum triglyceride (TG) levels. Seventy-one normal controls and 17 patients with isolated hypertriglyceridaemia were matched by age and gender. RESULTS Total and active fasting GLP-1 and 2-hour GLP-1 levels were not significantly altered among the 4 groups. However, total and active ΔGLP-1 levels (the difference between 2-hour GLP-1 and fasting GLP-1 levels) were significantly reduced in the isolated HTG, DM, and DM + HTG groups, particularly the DM + HTG group. The ratio of serum active GLP-1 (AGLP-1) to total GLP-1 (TGLP-1) levels was also decreased in patients with isolated HTG, suggesting that active GLP-1 secretion may be more seriously impaired. Both ΔTGLP-1 and ΔAGLP-1 levels were negatively correlated with serum TG levels, body mass index and fasting plasma glucose (FPG) levels and positively correlated with HDL-C levels. According to the multivariate linear regression analysis, only TG and FPG levels were independently associated with ΔTGLP-1 and ΔAGLP-1 levels. CONCLUSION Impaired GLP-1 secretion was associated with hypertriglyceridaemia and diabetes, and a more obvious association was noted in hypertriglyceridaemic patients with diabetes.
Collapse
Affiliation(s)
- Xiangxiang Wang
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Jia Liu
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Chaolin Li
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
- Department of Endocrinology, Yantai Yuhuangding Hospital Affiliated to Qingdao University, Yantai, China
| | - Meng Zhao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Lu Liu
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Qingbo Guan
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Haiqing Zhang
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Xu Zhang
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Ling Gao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Scientific Center, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Jiajun Zhao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| | - Yongfeng Song
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
- Institute of Endocrinology and Metabolism, Shandong Academy of Clinical Medicine, Jinan, China
| |
Collapse
|
19
|
Thombare K, Ntika S, Wang X, Krizhanovskii C. Long chain saturated and unsaturated fatty acids exert opposing effects on viability and function of GLP-1-producing cells: Mechanisms of lipotoxicity. PLoS One 2017; 12:e0177605. [PMID: 28520810 PMCID: PMC5433723 DOI: 10.1371/journal.pone.0177605] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 04/28/2017] [Indexed: 12/17/2022] Open
Abstract
Background and aim Fatty acids acutely stimulate GLP-1 secretion from L-cells in vivo. However, a high fat diet has been shown to reduce the density of L-cells in the mouse intestine and a positive correlation has been indicated between L-cell number and GLP-1 secretion. Thus, the mechanism of fatty acid-stimulated GLP-1 secretion, potential effects of long-term exposure to elevated levels of different fatty acid species, and underlying mechanisms are not fully understood. In the present study, we sought to determine how long-term exposure to saturated (16:0) and unsaturated (18:1) fatty acids, by direct effects on GLP-1-producing cells, alter function and viability, and the underlying mechanisms. Methods GLP-1-secreting GLUTag cells were cultured in the presence/absence of saturated (16:0) and unsaturated (18:1) fatty acids (0.125 mM for 48 h, followed by analyses of viability and apoptosis, as well as involvement of fatty acid oxidation, free fatty acid receptors (FFAR1) and ceramide synthesis. In addition, effects on the expression of proglucagon, prohormone convertase 1/3 (PC1/3), free fatty acid receptors (FFAR1, FFAR3), sodium glucose co-transporter (SGLT) and subsequent secretory response were determined. Results Saturated (16:0) and unsaturated (18:1) fatty acids exerted opposing effects on the induction of apoptosis (1.4-fold increase in DNA fragmentation by palmitate and a 0.5-fold reduction by oleate; p<0.01). Palmitate-induced apoptosis was associated with increased ceramide content and co-incubation with Fumonisin B1 abolished this lipo apoptosis. Oleate, on the other hand, reduced ceramide content, and—unlike palmitate—upregulated FFAR1 and FFAR3, evoking a 2-fold increase in FFAR1-mediated GLP-1 secretion following acute exposure to 0.125 mmol/L palmitate; (p<0.05). Conclusion/Interpretation Saturated (16:0), but not unsaturated (18:1), fatty acids induce ceramide-mediated apoptosis of GLP-1-producing cells. Further, unsaturated fatty acids confer lipoprotection, enhancing viability and function of GLP-1-secreting cells. These data provide potential mechanistic insight contributing to reduced L-cell mass following a high fat diet and differential effects of saturated and unsaturated fatty acids on GLP-1 secretion in vivo.
Collapse
Affiliation(s)
- Ketan Thombare
- Södertälje Hospital, Department of Internal Medicine, Södertälje, Sweden
| | - Stelia Ntika
- Södertälje Hospital, Department of Internal Medicine, Södertälje, Sweden
| | - Xuan Wang
- Södertälje Hospital, Department of Internal Medicine, Södertälje, Sweden
| | - Camilla Krizhanovskii
- Södertälje Hospital, Department of Internal Medicine, Södertälje, Sweden
- Karolinska Institute, Department of Molecular Medicine and Surgery, Stockholm, Sweden
- Uppsala University, Department of Medical Cell Biology, Uppsala, Sweden
- * E-mail:
| |
Collapse
|
20
|
Guo H, Li H, Wang B, Ding W, Ling L, Yang M, Gu Y, Niu J. Protective Effects of Glucagon-Like Peptide-1 Analog on Renal Tubular Injury in Mice on High-Fat Diet. Cell Physiol Biochem 2017; 41:1113-1124. [DOI: 10.1159/000464118] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/04/2017] [Indexed: 12/22/2022] Open
Abstract
Aims: The study aimed to investigate the renoprotective effect of glucagon-like peptide-1 (GLP-1) against renal tubular injury in C57BL/6 mice induced by a high-fat diet (HFD). Methods: Twenty C57BL/6 mice were fed HFD for 12 weeks. Ten of these mice were treated with GLP-1 at 200 µg/kg subcutaneously twice daily for 4 weeks (HFDG group), and the other ten mice received vehicle only (HFD group). Ten mice fed standard rodent chow served as controls (Con group). Body weight, kidney weight, food intake, and systolic blood pressure were measured. The expression of endoplasmic reticulum stress (ERS) markers (BIP, p-eIF2α, ATF4, and CHOP) and apoptosis in the kidney were examined utilizing western blotting, immunohistochemistry and TUNEL, respectively. Angiotensin II and angiotensin II type 1 receptor (AT1R) were examined by ELISA. Human proximal tubule epithelial cells (HK2) were treated with GLP-1(150 nM) followed by treatment with palmitic acid (500 nM [PA]) for 24 h. HK2 cells treated with BSA were used as controls. The protein levels of ERS markers, apoptosis-associated protein, and AT1R were measured by western blotting. Results: Increase of body weight, food intake, and systolic blood pressure was less pronounced in GLP-1 treated HFDG mice compared to HFD mice. The levels of ERS markers (BIP, p-eIF2α, ATF4, and CHOP) and apoptosis decreased following GLP-1 treatment in vivo and in vitro (p<0.05). Increased AT1R induced by HFD and PA were blocked with GLP-1 treatment. In contrast, the level of angiotensin II after GLP-1 treatment was not significantly different between the HFD and HFDG mice. Conclusion: The study indicated that saturated fatty acids induced ERS and apoptosis in the kidney and increased AT1R expression. GLP-1 treatment exerted renoprotective effects against saturated fatty acid-induced kidney tubular cell ERS and apoptosis together with inhibition of AT1R expression in vivo and in vitro.
Collapse
|
21
|
Beloqui A, Alhouayek M, Carradori D, Vanvarenberg K, Muccioli GG, Cani PD, Préat V. A Mechanistic Study on Nanoparticle-Mediated Glucagon-Like Peptide-1 (GLP-1) Secretion from Enteroendocrine L Cells. Mol Pharm 2016; 13:4222-4230. [DOI: 10.1021/acs.molpharmaceut.6b00871] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Ana Beloqui
- Université catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, 1200 Brussels, Belgium
| | - Mireille Alhouayek
- Université catholique de Louvain, Louvain Drug Research
Institute, Bioanalysis and Pharmacology of Bioactive Lipids Group, 1200 Brussels, Belgium
| | - Dario Carradori
- Université catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, 1200 Brussels, Belgium
| | - Kevin Vanvarenberg
- Université catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, 1200 Brussels, Belgium
| | - Giulio G. Muccioli
- Université catholique de Louvain, Louvain Drug Research
Institute, Bioanalysis and Pharmacology of Bioactive Lipids Group, 1200 Brussels, Belgium
| | - Patrice D. Cani
- Université catholique de Louvain, WELBIO (Walloon Excellence
in Life sciences and BIOtechnology), Louvain Drug Research Institute,
Metabolism and Nutrition Group, 1200 Brussels, Belgium
| | - Véronique Préat
- Université catholique de Louvain, Louvain Drug Research Institute, Advanced Drug Delivery and Biomaterials, 1200 Brussels, Belgium
| |
Collapse
|
22
|
Tong X, Kono T, Anderson-Baucum EK, Yamamoto W, Gilon P, Lebeche D, Day RN, Shull GE, Evans-Molina C. SERCA2 Deficiency Impairs Pancreatic β-Cell Function in Response to Diet-Induced Obesity. Diabetes 2016; 65:3039-52. [PMID: 27489309 PMCID: PMC5033263 DOI: 10.2337/db16-0084] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 07/28/2016] [Indexed: 12/18/2022]
Abstract
The sarcoendoplasmic reticulum (ER) Ca(2+) ATPase 2 (SERCA2) pump is a P-type ATPase tasked with the maintenance of ER Ca(2+) stores. Whereas β-cell SERCA2 expression is reduced in diabetes, the role of SERCA2 in the regulation of whole-body glucose homeostasis has remained uncharacterized. To this end, SERCA2 heterozygous mice (S2HET) were challenged with a high-fat diet (HFD) containing 45% of kilocalories from fat. After 16 weeks of the HFD, S2HET mice were hyperglycemic and glucose intolerant, but adiposity and insulin sensitivity were not different between HFD-fed S2HET mice and HFD-fed wild-type controls. Consistent with a defect in β-cell function, insulin secretion, glucose-induced cytosolic Ca(2+) mobilization, and the onset of steady-state glucose-induced Ca(2+) oscillations were impaired in HFD-fed S2HET islets. Moreover, HFD-fed S2HET mice exhibited reduced β-cell mass and proliferation, altered insulin production and proinsulin processing, and increased islet ER stress and death. In contrast, SERCA2 activation with a small molecule allosteric activator increased ER Ca(2+) storage and rescued tunicamycin-induced β-cell death. In aggregate, these data suggest a critical role for SERCA2 and the regulation of ER Ca(2+) homeostasis in the β-cell compensatory response to diet-induced obesity.
Collapse
Affiliation(s)
- Xin Tong
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN
| | | | - Wataru Yamamoto
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Patrick Gilon
- Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels, Belgium
| | - Djamel Lebeche
- Cardiovascular Research Institute and Diabetes Obesity and Metabolism Institute, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Richard N Day
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Gary E Shull
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Carmella Evans-Molina
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN Department of Medicine, Indiana University School of Medicine, Indianapolis, IN Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN Roudebush VA Medical Center, Indianapolis, IN
| |
Collapse
|
23
|
Blomain ES, Merlino DJ, Pattison AM, Snook AE, Waldman SA. Guanylyl Cyclase C Hormone Axis at the Intersection of Obesity and Colorectal Cancer. Mol Pharmacol 2016; 90:199-204. [PMID: 27251363 DOI: 10.1124/mol.115.103192] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/25/2016] [Indexed: 12/12/2022] Open
Abstract
Obesity has emerged as a principal cause of mortality worldwide, reflecting comorbidities including cancer risk, particularly in colorectum. Although this relationship is established epidemiologically, molecular mechanisms linking colorectal cancer and obesity continue to be refined. Guanylyl cyclase C (GUCY2C), a membrane-bound guanylyl cyclase expressed in intestinal epithelial cells, binds the paracrine hormones guanylin and uroguanylin, inducing cGMP signaling in colorectum and small intestine, respectively. Guanylin is the most commonly lost gene product in sporadic colorectal cancer, and its universal loss early in transformation silences GUCY2C, a tumor suppressor, disrupting epithelial homeostasis underlying tumorigenesis. In small intestine, eating induces endocrine secretion of uroguanylin, the afferent limb of a novel gut-brain axis that activates hypothalamic GUCY2C-cGMP signaling mediating satiety opposing obesity. Recent studies revealed that diet-induced obesity suppressed guanylin and uroguanylin expression in mice and humans. Hormone loss reflects reversible calorie-induced endoplasmic reticulum stress and the associated unfolded protein response, rather than the endocrine, adipokine, or inflammatory milieu of obesity. Loss of intestinal uroguanylin secretion silences the hypothalamic GUCY2C endocrine axis, creating a feed-forward loop contributing to hyperphagia in obesity. Importantly, calorie-induced guanylin loss silences the GUCY2C-cGMP paracrine axis underlying obesity-induced epithelial dysfunction and colorectal tumorigenesis. Indeed, genetically enforced guanylin replacement eliminated diet-induced intestinal tumorigenesis in mice. Taken together, these observations suggest that GUCY2C hormone axes are at the intersection of obesity and colorectal cancer. Moreover, they suggest that hormone replacement that restores GUCY2C signaling may be a novel therapeutic paradigm to prevent both hyperphagia and intestinal tumorigenesis in obesity.
Collapse
Affiliation(s)
- Erik S Blomain
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Dante J Merlino
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Amanda M Pattison
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Adam E Snook
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Scott A Waldman
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
| |
Collapse
|
24
|
Abstract
Glucagon-like peptide-1 (GLP-1) is a peptide hormone, released from intestinal L-cells in response to hormonal, neural and nutrient stimuli. In addition to potentiation of meal-stimulated insulin secretion, GLP-1 signalling exerts numerous pleiotropic effects on various tissues, regulating energy absorption and disposal, as well as cell proliferation and survival. In Type 2 Diabetes (T2D) reduced plasma levels of GLP-1 have been observed, and plasma levels of GLP-1, as well as reduced numbers of GLP-1 producing cells, have been correlated to obesity and insulin resistance. Increasing endogenous secretion of GLP-1 by selective targeting of the molecular mechanisms regulating secretion from the L-cell has been the focus of much recent research. An additional and promising strategy for enhancing endogenous secretion may be to increase the L-cell mass in the intestinal epithelium, but the mechanisms that regulate the growth, survival and function of these cells are largely unknown. We recently showed that prolonged exposure to high concentrations of the fatty acid palmitate induced lipotoxic effects, similar to those operative in insulin-producing cells, in an in vitro model of GLP-1-producing cells. The mechanisms inducing this lipototoxicity involved increased production of reactive oxygen species (ROS). In this review, regulation of GLP-1-secreting cells is discussed, with a focus on the mechanisms underlying GLP-1 secretion, long-term regulation of growth, differentiation and survival under normal as well as diabetic conditions of hypernutrition.
Collapse
|
25
|
Poudyal H. Mechanisms for the cardiovascular effects of glucagon-like peptide-1. Acta Physiol (Oxf) 2016; 216:277-313. [PMID: 26384481 DOI: 10.1111/apha.12604] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/25/2015] [Accepted: 09/10/2015] [Indexed: 12/16/2022]
Abstract
Over the past three decades, at least 10 hormones secreted by the enteroendocrine cells have been discovered, which directly affect the cardiovascular system through their innate receptors expressed in the heart and blood vessels or through a neural mechanism. Glucagon-like peptide-1 (GLP-1), an important incretin, is perhaps best studied of these gut-derived hormones with important cardiovascular effects. In this review, I have discussed the mechanism of GLP-1 release from the enteroendocrine L-cells and its physiological effects on the cardiovascular system. Current evidence suggests that GLP-1 has positive inotropic and chronotropic effects on the heart and may be important in preserving left ventricular structure and function by direct and indirect mechanisms. The direct effects of GLP-1 in the heart may be mediated through GLP-1R expressed in atria as well as arteries and arterioles in the left ventricle and mainly involve in the activation of multiple pro-survival kinases and enhanced energy utilization. There is also good evidence to support the involvement of a second, yet to be identified, GLP-1 receptor. Further, GLP-1(9-36)amide, which was previously thought to be the inactive metabolite of the active GLP-1(7-36)amide, may also have direct cardioprotective effects. GLP-1's action on GLP-1R expressed in the central nervous system, kidney, vasculature and the pancreas may indirectly contribute to its cardioprotective effects.
Collapse
Affiliation(s)
- H. Poudyal
- Department of Diabetes, Endocrinology and Nutrition; Graduate School of Medicine and Hakubi Centre for Advanced Research; Kyoto University; Kyoto Japan
| |
Collapse
|
26
|
Clara R, Langhans W, Mansouri A. Oleic acid stimulates glucagon-like peptide-1 release from enteroendocrine cells by modulating cell respiration and glycolysis. Metabolism 2016; 65:8-17. [PMID: 26892511 DOI: 10.1016/j.metabol.2015.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/22/2015] [Accepted: 10/01/2015] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Glucagon-like peptide-1 (GLP-1) is a potent satiating and incretin hormone released by enteroendocrine L-cells in response to eating. Dietary fat, in particular monounsaturated fatty acids, such as oleic acid (OA), potently stimulates GLP-1 secretion from L-cells. It is, however, unclear whether the intracellular metabolic handling of OA is involved in this effect. METHODS First we determined the optimal medium for the bioenergetics measurements. Then we examined the effect of OA on the metabolism of the immortalized enteroendocrine GLUTag cell model and assessed GLP-1 release in parallel. We measured oxygen consumption rate and extracellular acidification rate in response to OA and to different metabolic inhibitors with the Seahorse extracellular flux analyzer. RESULTS OA increased cellular respiration and potently stimulated GLP-1 release. The fatty acid oxidation inhibitor etomoxir did neither reduce OA-induced respiration nor affect the OA-induced GLP-1 release. In contrast, inhibition of the respiratory chain or of downstream steps of aerobic glycolysis reduced the OA-induced GLP-1 release, and an inhibition of the first step of glycolysis by addition of 2-deoxy-d-glucose even abolished it. CONCLUSION These findings indicate that an indirect stimulation of glycolysis is crucial for the OA-induced release of GLP-1.
Collapse
Affiliation(s)
- Rosmarie Clara
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach (Zürich), Switzerland
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach (Zürich), Switzerland
| | - Abdelhak Mansouri
- Physiology and Behavior Laboratory, ETH Zürich, 8603 Schwerzenbach (Zürich), Switzerland.
| |
Collapse
|
27
|
Abstract
The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation.
Collapse
Affiliation(s)
- Ramona Pais
- The Wellcome Trust–MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Fiona M. Gribble
- The Wellcome Trust–MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrookes’s Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, UK
| | | |
Collapse
|
28
|
Du Q, Hosoda H, Umekawa T, Kinouchi T, Ito N, Miyazato M, Kangawa K, Ikeda T. Postnatal weight gain induced by overfeeding pups and maternal high-fat diet during the lactation period modulates glucose metabolism and the production of pancreatic and gastrointestinal peptides. Peptides 2015; 70:23-31. [PMID: 26022984 DOI: 10.1016/j.peptides.2015.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 04/14/2015] [Accepted: 05/05/2015] [Indexed: 12/25/2022]
Abstract
The impact of rapid weight gain on glucose metabolism during the early postnatal period remains unclear. We investigated the influence of rapid weight gain under different nutritional conditions on glucose metabolism, focusing on the production of pancreatic and gastric peptides. On postnatal day (PND) 2, C57BL/6N pups were divided into three groups: control (C) pups whose dams were fed a control diet (10%kcal fat) and nursed 10 pups each; maternal high-fat diet (HFD) pups whose dams were fed an HFD (45%kcal fat) and nursed 10 pups each; and overfeeding (OF) pups whose dams were fed the control diet and nursed 4 pups each. Data were collected on PND 7, 14 and 21. The body weight gains of the HFD and OF pups were 1.2 times higher than that of the C pups. On PND 14, the HFD pups had higher blood glucose levels, but there were no significant differences in serum insulin levels between the HFD and C pups. The OF pups had higher blood glucose and serum insulin levels than that of the C pups. Insulin resistance was found in the HFD and OF pups. On PND 14, the content of incretins in the jejunum was increased in the OF pups, and acyl ghrelin in the stomach was upregulated in the HFD and OF pups. These results suggest that neonatal weight gain induced by overfeeding pups and maternal high-fat diet during the early postnatal period modulates the insulin sensitivity and the production of pancreatic and gastrointestinal peptides.
Collapse
Affiliation(s)
- Qinwen Du
- Department of Obstetrics and Gynecology, Mie University Graduate School of Medicine, Tsu, Japan; Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Hiroshi Hosoda
- Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan.
| | - Takashi Umekawa
- Department of Obstetrics and Gynecology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Toshi Kinouchi
- Nutrition Research Department, Meiji Co., Ltd., Odawara, Japan
| | - Natsuki Ito
- Nutrition Research Department, Meiji Co., Ltd., Odawara, Japan
| | - Mikiya Miyazato
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Kenji Kangawa
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Osaka, Japan
| | - Tomoaki Ikeda
- Department of Obstetrics and Gynecology, Mie University Graduate School of Medicine, Tsu, Japan
| |
Collapse
|
29
|
Sato T, Hayashi H, Hiratsuka M, Hirasawa N. Glucocorticoids decrease the production of glucagon-like peptide-1 at the transcriptional level in intestinal L-cells. Mol Cell Endocrinol 2015; 406:60-7. [PMID: 25700603 DOI: 10.1016/j.mce.2015.02.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 01/13/2015] [Accepted: 02/13/2015] [Indexed: 01/28/2023]
Abstract
Glucocorticoids are widely used as anti-inflammatory or immunosuppressive drugs, but often induce hyperglycemia as a side effect. Glucagon-like peptide-1 (GLP-1) is secreted from intestinal L cells and plays crucial roles in maintaining glucose homeostasis. However, the direct effects of glucocorticoids on the GLP-1 production pathway in L cells remain unclear. We investigated the effects of glucocorticoids on GLP-1 production in vitro and in vivo. In L cell lines, glucocorticoids decreased GLP-1 release and expression of the precursor, proglucagon, at protein and mRNA levels, which were inhibited by mifepristone. The administration of dexamethasone or budesonide to mice significantly decreased the mRNA expression of proglucagon in the ileum and partially decreased glucose-stimulated GLP-1 secretion. Compound A, a dissociated glucocorticoid receptor modulator, did not affect the expression of proglucagon in vitro. These results suggested that glucocorticoids directly reduced GLP-1 production at the transcriptional level in L cells through a glucocorticoid receptor dimerization-dependent mechanism.
Collapse
Affiliation(s)
- Taiki Sato
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Hiroto Hayashi
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
| |
Collapse
|
30
|
Wang X, Liu H, Chen J, Li Y, Qu S. Multiple Factors Related to the Secretion of Glucagon-Like Peptide-1. Int J Endocrinol 2015; 2015:651757. [PMID: 26366173 PMCID: PMC4558455 DOI: 10.1155/2015/651757] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 08/02/2015] [Accepted: 08/03/2015] [Indexed: 12/15/2022] Open
Abstract
The glucagon-like peptide-1 is secreted by intestinal L cells in response to nutrient ingestion. It regulates the secretion and sensitivity of insulin while suppressing glucagon secretion and decreasing postprandial glucose levels. It also improves beta-cell proliferation and prevents beta-cell apoptosis induced by cytotoxic agents. Additionally, glucagon-like peptide-1 delays gastric emptying and suppresses appetite. The impaired secretion of glucagon-like peptide-1 has negative influence on diabetes, hyperlipidemia, and insulin resistance related diseases. Thus, glucagon-like peptide-1-based therapies (glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) are now well accepted in the management of type 2 diabetes. The levels of glucagon-like peptide-1 are influenced by multiple factors including a variety of nutrients. The component of a meal acts as potent stimulants of glucagon-like peptide-1 secretion. The levels of its secretion change with the intake of different nutrients. Some drugs also have influence on GLP-1 secretion. Bariatric surgery may improve metabolism through the action on GLP-1 levels. In recent years, there has been a great interest in developing effective methods to regulate glucagon-like peptide-1 secretion. This review summarizes the literature on glucagon-like peptide-1 and related factors affecting its levels.
Collapse
Affiliation(s)
- XingChun Wang
- Department of Endocrinology and Metabolism, Shanghai 10th People's Hospital, Tongji University, Shanghai 200072, China
| | - Huan Liu
- Department of Urology, Zhenjiang First People's Hospital, Zhenjiang, Jiangsu 212002, China
| | - Jiaqi Chen
- Department of Endocrinology and Metabolism, Shanghai 10th People's Hospital, Tongji University, Shanghai 200072, China
- Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Yan Li
- Department of Endocrinology and Metabolism, Shanghai 10th People's Hospital, Tongji University, Shanghai 200072, China
- Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Shen Qu
- Department of Endocrinology and Metabolism, Shanghai 10th People's Hospital, Tongji University, Shanghai 200072, China
- Nanjing Medical University, Nanjing, Jiangsu 210029, China
- *Shen Qu:
| |
Collapse
|
31
|
Moon ML, Joesting JJ, Lawson MA, Chiu GS, Blevins NA, Kwakwa KA, Freund GG. The saturated fatty acid, palmitic acid, induces anxiety-like behavior in mice. Metabolism 2014; 63:1131-40. [PMID: 25016520 PMCID: PMC4151238 DOI: 10.1016/j.metabol.2014.06.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 06/03/2014] [Accepted: 06/03/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Excess fat in the diet can impact neuropsychiatric functions by negatively affecting cognition, mood and anxiety. We sought to show that the free fatty acid (FFA), palmitic acid, can cause adverse biobehaviors in mice that last beyond an acute elevation in plasma FFAs. METHODS Mice were administered palmitic acid or vehicle as a single intraperitoneal (IP) injection. Biobehaviors were profiled 2 and 24 h after palmitic acid treatment. Quantification of dopamine (DA), norepinephrine (NE), serotonin (5-HT) and their major metabolites was performed in cortex, hippocampus and amygdala. FFA concentration was determined in plasma. Relative fold change in mRNA expression of unfolded protein response (UPR)-associated genes was determined in brain regions. RESULTS In a dose-dependent fashion, palmitic acid rapidly reduced mouse locomotor activity by a mechanism that did not rely on TLR4, MyD88, IL-1, IL-6 or TNFα but was dependent on fatty acid chain length. Twenty-four hours after palmitic acid administration mice exhibited anxiety-like behavior without impairment in locomotion, food intake, depressive-like behavior or spatial memory. Additionally, the serotonin metabolite 5-HIAA was increased by 33% in the amygdala 24h after palmitic acid treatment. CONCLUSIONS Palmitic acid induces anxiety-like behavior in mice while increasing amygdala-based serotonin metabolism. These effects occur at a time point when plasma FFA levels are no longer elevated.
Collapse
Affiliation(s)
- Morgan L Moon
- Division of Nutritional Sciences, University of Illinois, Urbana IL, USA
| | - Jennifer J Joesting
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana IL, USA
| | - Marcus A Lawson
- Department of Animal Sciences, University of Illinois, Urbana IL, USA
| | - Gabriel S Chiu
- Division of Nutritional Sciences, University of Illinois, Urbana IL, USA
| | - Neil A Blevins
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana IL, USA
| | - Kristin A Kwakwa
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana IL, USA
| | - Gregory G Freund
- Division of Nutritional Sciences, University of Illinois, Urbana IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana IL, USA; Department of Animal Sciences, University of Illinois, Urbana IL, USA.
| |
Collapse
|
32
|
Aronis KN, Tsoukas MA, Mantzoros CS. Potential cardioprotective action of GLP-1: from bench to bedside. Metabolism 2014; 63:979-88. [PMID: 24956977 DOI: 10.1016/j.metabol.2014.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 05/16/2014] [Indexed: 12/18/2022]
Affiliation(s)
- Konstantinos N Aronis
- Section of Endocrinology, Boston VA Healthcare System, Jamaica Plain, MA; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Department of Medicine, Boston Medical Center, Boston University, 72 Evans Street, Boston, MA 02217.
| | - Michael A Tsoukas
- Section of Endocrinology, Boston VA Healthcare System, Jamaica Plain, MA; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Christos S Mantzoros
- Section of Endocrinology, Boston VA Healthcare System, Jamaica Plain, MA; Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Department of Medicine, Boston Medical Center, Boston University, 72 Evans Street, Boston, MA 02217
| |
Collapse
|
33
|
Kuwahara A. Contributions of colonic short-chain Fatty Acid receptors in energy homeostasis. Front Endocrinol (Lausanne) 2014; 5:144. [PMID: 25228897 PMCID: PMC4150999 DOI: 10.3389/fendo.2014.00144] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 08/19/2014] [Indexed: 12/12/2022] Open
Abstract
The gastrointestinal (GI) tract is separated from the body's internal environment by a single layer of epithelial cells, through which nutrients must pass for their absorption into the bloodstream. Besides food and drink, the GI lumen is also exposed to bioactive chemicals and bacterial products including short-chain fatty acids (SCFAs). Therefore, the GI tract has to monitor the composition of its contents continuously to discriminate between necessary and unnecessary compounds. Recent molecular identification of epithelial membrane receptor proteins has revealed the sensory roles of intestinal epithelial cells in the gut chemosensory system. Malfunctioning of these receptors may be responsible for a variety of metabolic dysfunctions associated with obesity and related disorders. Recent studies suggest that SCFAs produced by microbiota fermentation act as signaling molecules and influence the host's metabolism; uncovering the sensory mechanisms of such bacterial metabolites would help us understand the interactions between the host and microbiota in host energy homeostasis. In this review, the contribution of colonic SCFA receptors in energy metabolism and our recent findings concerning the possible link between SCFA receptors and host energy homeostasis are discussed.
Collapse
Affiliation(s)
- Atsukazu Kuwahara
- Laboratory of Physiology, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
- *Correspondence: Atsukazu Kuwahara, Laboratory of Physiology, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan e-mail:
| |
Collapse
|