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Pérez-Arana GM, Díaz-Gómez A, Bancalero-de los Reyes J, Gracia-Romero M, Ribelles-García A, Visiedo F, González-Domínguez Á, Almorza-Gomar D, Prada-Oliveira JA. The role of glucagon after bariatric/metabolic surgery: much more than an "anti-insulin" hormone. Front Endocrinol (Lausanne) 2023; 14:1236103. [PMID: 37635984 PMCID: PMC10451081 DOI: 10.3389/fendo.2023.1236103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/21/2023] [Indexed: 08/29/2023] Open
Abstract
The biological activity of glucagon has recently been proposed to both stimulate hepatic glucose production and also include a paradoxical insulinotropic effect, which could suggest a new role of glucagon in the pathophysiology type 2 diabetes mellitus (T2DM). An insulinotropic role of glucagon has been observed after bariatric/metabolic surgery that is mediated through the GLP-1 receptor on pancreatic beta cells. This effect appears to be modulated by other members of the proglucagon family, playing a key role in the beneficial effects and complications of bariatric/metabolic surgery. Glucagon serves a dual role after sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). In addition to maintaining blood glucose levels, glucagon exhibits an insulinotropic effect, suggesting that glucagon has a more complex function than simply an "anti-insulin hormone".
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Affiliation(s)
- Gonzalo-Martín Pérez-Arana
- Department of Human Anatomy and Embryology, University of Cadiz, Cádiz, Spain
- Institute for Biomedical Science Research and Innovation (INIBICA), University of Cadiz, Cádiz, Spain
| | | | | | | | | | - Francisco Visiedo
- Department of Human Anatomy and Embryology, University of Cadiz, Cádiz, Spain
- Institute for Biomedical Science Research and Innovation (INIBICA), University of Cadiz, Cádiz, Spain
| | - Álvaro González-Domínguez
- Institute for Biomedical Science Research and Innovation (INIBICA), University of Cadiz, Cádiz, Spain
| | - David Almorza-Gomar
- Institute for Biomedical Science Research and Innovation (INIBICA), University of Cadiz, Cádiz, Spain
- Operative Statistic and Research Department, University of Cádiz, Cádiz, Spain
| | - José-Arturo Prada-Oliveira
- Department of Human Anatomy and Embryology, University of Cadiz, Cádiz, Spain
- Institute for Biomedical Science Research and Innovation (INIBICA), University of Cadiz, Cádiz, Spain
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Arjunolic acid from Cyclocarya paliurus selectively inhibits glucagon secretion from α cells and ameliorates diabetes via ephrin-A1 and EphA4 interaction. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Takatani T, Shirakawa J, Shibue K, Gupta MK, Kim H, Lu S, Hu J, White MF, Kennedy RT, Kulkarni RN. Insulin receptor substrate 1, but not IRS2, plays a dominant role in regulating pancreatic alpha cell function in mice. J Biol Chem 2021; 296:100646. [PMID: 33839150 PMCID: PMC8131928 DOI: 10.1016/j.jbc.2021.100646] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/24/2021] [Accepted: 04/07/2021] [Indexed: 11/29/2022] Open
Abstract
Dysregulated glucagon secretion deteriorates glycemic control in type 1 and type 2 diabetes. Although insulin is known to regulate glucagon secretion via its cognate receptor (insulin receptor, INSR) in pancreatic alpha cells, the role of downstream proteins and signaling pathways underlying insulin's activities are not fully defined. Using in vivo (knockout) and in vitro (knockdown) studies targeting insulin receptor substrate (IRS) proteins, we compared the relative roles of IRS1 and IRS2 in regulating alpha cell function. Alpha cell-specific IRS1-knockout mice exhibited glucose intolerance and inappropriate glucagon suppression during glucose tolerance tests. In contrast, alpha cell-specific IRS2-knockout animals manifested normal glucose tolerance and suppression of glucagon secretion after glucose administration. Alpha cell lines with stable IRS1 knockdown could not repress glucagon mRNA expression and exhibited a reduction in phosphorylation of AKT Ser/Thr kinase (AKT, at Ser-473 and Thr-308). AlphaIRS1KD cells also displayed suppressed global protein translation, including reduced glucagon expression, impaired cytoplasmic Ca2+ response, and mitochondrial dysfunction. This was supported by the identification of novel IRS1-specific downstream target genes, Trpc3 and Cartpt, that are associated with glucagon regulation in alpha cells. These results provide evidence that IRS1, rather than IRS2, is a dominant regulator of pancreatic alpha cell function.
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Affiliation(s)
- Tomozumi Takatani
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Jun Shirakawa
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation (IMCR), Gunma University, Gunma, Japan
| | - Kimitaka Shibue
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Manoj K Gupta
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Cell Therapy Translational Engine (CTTE), Takeda Pharmaceuticals, Cambridge, Massachusetts, USA
| | - Hyunki Kim
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Shusheng Lu
- Departments of Chemistry and Pharmacology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jiang Hu
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Morris F White
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert T Kennedy
- Departments of Chemistry and Pharmacology, University of Michigan, Ann Arbor, Michigan, USA
| | - Rohit N Kulkarni
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, USA.
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Mancuso E, Mannino GC, Fuoco A, Leo A, Citraro R, Averta C, Spiga R, Russo E, De Sarro G, Andreozzi F, Sesti G. HDL (High-Density Lipoprotein) and ApoA-1 (Apolipoprotein A-1) Potentially Modulate Pancreatic α-Cell Glucagon Secretion. Arterioscler Thromb Vasc Biol 2020; 40:2941-2952. [PMID: 33086869 DOI: 10.1161/atvbaha.120.314640] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Subjects with low levels of HDL (high-density lipoprotein) and ApoA-1 (apolipoprotein A-1) have increased risk to develop type 2 diabetes. HDL levels are an independent predictor of β-cell function and positively modulate it. Type 2 diabetes is characterized by defects in both β and α-cell function, but the effect of HDL and ApoA1 on α-cell function is unknown. Approach and Results: We observed a significant negative correlation (r=-0.422, P<0.0001) between HDL levels and fasting glucagon in a cohort of 132 Italian subjects. In a multivariable regression analysis including potential confounders such as age, sex, BMI, triglycerides, total cholesterol, fasting and 2-hour postload glucose, and fasting insulin, the association between HDL and fasting glucagon remained statistically significant (β=-0.318, P=0.006). CD1 mice treated with HDL or ApoA-1 for 3 consecutive days showed a 32% (P<0.001) and 23% (P<0.05) reduction, respectively, in glucagon levels following insulin-induced hypoglycemia, compared with controls. Treatment of pancreatic αTC1 clone 6 cells with HDL or ApoA-1 for 24 hours resulted in a significant reduction of glucagon expression (P<0.04) and secretion (P<0.01) after an hypoglycemic stimulus and increased Akt (RAC-alpha serine/threonine-protein kinase) and FoxO1 (forkhead/winged helix box gene, group O-1) phosphorylation. Pretreatment with Akt inhibitor VIII, PI3K (phosphatidylinositol 3-kinase) inhibitor LY294002, and HDL receptor SCARB-1 (scavenger receptor class B type 1) inhibitor BLT-1 (block lipid transport-1) restored αTC1 cell response to low glucose levels. CONCLUSIONS These results support the notion that HDL and ApoA-1 modulate glucagon expression and secretion by binding their cognate receptor SCARB-1, and activating the PI3K/Akt/FoxO1 signaling cascade in an in vitro α-cell model. Overall, these results raise the hypothesis that HDL and ApoA-1 may have a role in modulating glucagon secretion.
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Affiliation(s)
- Elettra Mancuso
- Department of Medical and Surgical Sciences (E.M., G.C.M., A.F., C.A., R.S., F.A.), University Magna Graecia of Catanzaro, Italy
| | - Gaia Chiara Mannino
- Department of Medical and Surgical Sciences (E.M., G.C.M., A.F., C.A., R.S., F.A.), University Magna Graecia of Catanzaro, Italy
| | - Anastasia Fuoco
- Department of Medical and Surgical Sciences (E.M., G.C.M., A.F., C.A., R.S., F.A.), University Magna Graecia of Catanzaro, Italy
| | - Antonio Leo
- Department of Science of Health (A.L., R.C., E.R., G.D.S.), University Magna Graecia of Catanzaro, Italy
| | - Rita Citraro
- Department of Science of Health (A.L., R.C., E.R., G.D.S.), University Magna Graecia of Catanzaro, Italy
| | - Carolina Averta
- Department of Medical and Surgical Sciences (E.M., G.C.M., A.F., C.A., R.S., F.A.), University Magna Graecia of Catanzaro, Italy
| | - Rosangela Spiga
- Department of Medical and Surgical Sciences (E.M., G.C.M., A.F., C.A., R.S., F.A.), University Magna Graecia of Catanzaro, Italy
| | - Emilio Russo
- Department of Science of Health (A.L., R.C., E.R., G.D.S.), University Magna Graecia of Catanzaro, Italy
| | - Giovambattista De Sarro
- Department of Science of Health (A.L., R.C., E.R., G.D.S.), University Magna Graecia of Catanzaro, Italy
| | - Francesco Andreozzi
- Department of Medical and Surgical Sciences (E.M., G.C.M., A.F., C.A., R.S., F.A.), University Magna Graecia of Catanzaro, Italy
| | - Giorgio Sesti
- Department of Clinical and Molecular Medicine, University of Rome-Sapienza, Italy (G.S.)
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Zhuang Y, Xing C, Cao H, Zhang C, Luo J, Guo X, Hu G. Insulin resistance and metabonomics analysis of fatty liver haemorrhagic syndrome in laying hens induced by a high-energy low-protein diet. Sci Rep 2019; 9:10141. [PMID: 31300671 PMCID: PMC6626135 DOI: 10.1038/s41598-019-46183-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 06/24/2019] [Indexed: 12/31/2022] Open
Abstract
Fatty liver haemorrhagic syndrome (FLHS) is a widespread metabolic disease in laying hens that causes a decrease in egg production and even death. Insulin resistance is a major contributor to the pathogenesis of nonalcoholic fatty liver disease. However, the relationship between FLHS and the insulin resistance mechanisms underlying FLHS is not well elucidated. Therefore, we established an FLHS model induced by feeding a high-energy low-protein diet. In the current study, we found that the fasting glucose and insulin concentrations were elevated in the FLHS group compared with the control group during the experimental period. The results of the oral glucose tolerance test (OGTT) and insulin sensitivity test (IST) showed a high level of insulin resistance in the FLHS model. InsR, 4EBP-1, Glut-1 and Glut-3 mRNA expression were decreased, and TOR, S6K1, and FOXO1 were elevated (P < 0.05). Metabolomic analysis with GC/MS identified 46 differentially expressed metabolites between these two groups, and of these, 14 kinds of metabolism molecules and 32 kinds of small metabolism molecules were decreased (P < 0.05). Further investigation showed that glucose, lipid and amino acid metabolism blocks in the progression of FLHS by GO functional and pathway analysis. Overall, these results suggest that insulin resistance participated in FLHS; comprehensively, metabolites participated in the dysregulated biological process.
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Affiliation(s)
- Yu Zhuang
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China
| | - Chenghong Xing
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China
| | - Huabin Cao
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China
| | - Caiying Zhang
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China
| | - Junrong Luo
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China
| | - Xiaoquan Guo
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China
| | - Guoliang Hu
- Jiangxi Provincial Key Laboratory for Animal Health, Institute of Animal Population Health, College of Animal Science and Technology, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Economic and Technological Development District, Nanchang, 330045, Jiangxi, P.R. China.
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Zhang H, Liu R, Deng T, Wang X, Lang H, Qu Y, Duan J, Huang D, Ying G, Ba Y. The microRNA-124-iGluR2/3 pathway regulates glucagon release from alpha cells. Oncotarget 2017; 7:24734-43. [PMID: 27013590 PMCID: PMC5029737 DOI: 10.18632/oncotarget.8270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/07/2016] [Indexed: 01/30/2023] Open
Abstract
Glucagon, secreted from islet alpha cells, plays an important role in regulating glucose homeostasis; however, the molecular mechanism underlying this process is not fully understood. Previous studies have demonstrated that miRNAs are involved in the function of alpha cells. Glutamate promotes glucagon secretion by mediating the opening of Ca2+ channels. In this present, iGluR2 and iGluR3 levels were significantly increased in fasting-treated mouse islets. Additional studies showed that miR-124-3p simultaneously regulates the expression of iGluR2 and iGluR3 through the direct targeting of mRNA 3’UTR of these two genes. The miR-124-iGluRs pathway also contributed to the high level of glucagon secretion through long-term high glucose levels. Thus, a novel pathway comprising miRNA, glutamate and iGluRs has been demonstrated to regulate the biological process of glucagon release.
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Affiliation(s)
- Haiyang Zhang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Rui Liu
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Ting Deng
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Xia Wang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Hongmei Lang
- Department of Endocrinology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, China
| | - Yanjun Qu
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Jingjing Duan
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Dingzhi Huang
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Guoguang Ying
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Yi Ba
- Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
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Kim M, Lee EJ, Shin HM, Jung HS, Kim TK, Kim TN, Kwon MJ, Lee SH, Rhee BD, Park JH. The effect of PPARγ agonist on SGLT2 and glucagon expressions in alpha cells under hyperglycemia. J Endocrinol Invest 2017; 40:1069-1076. [PMID: 28391584 DOI: 10.1007/s40618-017-0659-1] [Citation(s) in RCA: 3] [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: 12/09/2016] [Accepted: 03/17/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND Although sodium glucose cotransporter 2 (SGLT2) inhibitors have many beneficial effects for type 2 diabetes, including decreased cardiovascular death, recent reports that they increased glucagon through SGLT2 inhibition raised some concern. Troglitazone, Peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, was reported to increase SGLT2 in renal proximal tubule cells, but its role on pancreatic alpha cells have not been reported. We investigated the effect of troglitazone on SGLT2 expression in alpha cells and subsequent glucagon regulation in hyperglycemia. METHODS An Alpha TC1-6 cell line was cultured in control (5 mM) or hyperglycemia (HG, 15 mM) for 72 h. We applied troglitazone with or without PPARγ antagonist (GW9662 10 μM). To investigate the involvement of PI3K/Akt pathway, we applied troglitazone with or without Wortmanin. We measured sodium glucose transporter 2 (SGLT2) and glucagon (GCG) mRNA and protein expression. PPAR gamma, PI3K and Akt protein were also measured. RESULTS Exposure of alpha TC cells to HG for 72 h increased glucagon mRNA and protein expression. HG decreased SGLT2 mRNA and protein expression. Troglitazone significantly reversed HG-induced reduction of SGLT2 expression and increase of glucagon secretion. PPARγ antagonist (GW9662 10 μM) decreased the expression of SGLT2 and increased glucagon as HG did. Hyperglycemia increased PI3K and pAkt expression in alpha cells. Wortmanin (PI3K inhibitor, 1 μM) reversed HG-induced SGLT2 decrease and glucagon increase. Troglitazone treatment decreased PI3K and pAkt expression in HG. CONCLUSION In conclusion, PPARγ agonist, troglitazone improved glucose transport SGLT2 dysfunction and subsequent glucagon dysregulation in alpha cell under hyperglycemia. Those effects were through the involvement of PI3K/pAkt signaling pathway. This study may add one more reason for the ideal combination of PPARγ agonist and SGLT2 inhibitor in clinical practice.
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Affiliation(s)
- M Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea.
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea.
| | - E J Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - H M Shin
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea
| | - H S Jung
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea
| | - T K Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - T N Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - M J Kwon
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - S H Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - B D Rhee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
| | - J H Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, 875, Hauendae-ro, Hauendae-gu, Busan, 612-862, South Korea
- Molecular Therapy Lab, Paik Institute for Clinical Research, Inje University, Busan, South Korea
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Solini A, Sebastiani G, Nigi L, Santini E, Rossi C, Dotta F. Dapagliflozin modulates glucagon secretion in an SGLT2-independent manner in murine alpha cells. DIABETES & METABOLISM 2017; 43:512-520. [PMID: 28499695 DOI: 10.1016/j.diabet.2017.04.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/28/2017] [Accepted: 04/13/2017] [Indexed: 12/20/2022]
Abstract
AIM SGLT2 inhibitors reduce renal glucose uptake through an insulin-independent mechanism. They also increase glucagon concentration, although the extent to which this is due to a direct effect on pancreatic alpha cells remains unclear. METHODS In the present work, αTC1 cells treated with the SGLT2 inhibitor dapagliflozin (Dapa) were analyzed for glucose transporters, molecular mediators of hormone secretion, glucagon and GLP-1 release, and the effects of somatostatin. Data were validated in murine and human pancreatic islets. RESULTS SLC5A2 (the SGLT2-encoding gene) was nearly undetectable in αTC1 cells, not even by a digital PCR technique using different probes. In contrast, SLC5A1 (the SGLT1-encoding gene) was constitutively abundant in αTC1 cells and in islets, and increased with Dapa. This was associated with greater glucagon release, preceded by increased expression of preproglucagon and HNF4α. Looking at the candidate intracellular signalling pathway, reduced PASK and increased AMPK-α2 expression were also detected. GLUT1 and GLUT2, as well as regulators of glucagon release and alpha-cell phenotype (chromogranin A, paired box 6, proprotein convertase 1/2, synaptophysin), were unaffected by Dapa, as were GLP-1 receptor expression and GLP-1 release. Low glucose did not influence the stimulatory effect of Dapa on glucagon release, but was instead almost fully reverted by SLC5A1 silencing. When the effect of Dapa on AMPK and PASK, emerging regulators of lipid and glucose metabolism, was tested, upregulated AMPK-α2 appeared to be involved in molecular signalling. CONCLUSION Our study has shown that, in αTC1 cells, Dapa acutely upregulates SGLT1 expression and increases glucagon release through an SGLT1-dependent mechanism, with SGLT2 expression virtually undetectable. These results suggest the involvement of SGLT1 in modulating glucagon increases following SGLT2 inhibition.
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Affiliation(s)
- A Solini
- Department of surgical, medical, molecular and critical area pathology, university of Pisa, Via Roma 67, 56126 Pisa, Italy.
| | - G Sebastiani
- Department of medicine, surgery and neuroscience, university of Siena and Fondazione Umberto di Mario-Toscana life science, Viale Bracci 18, 53100 Siena, Italy
| | - L Nigi
- Department of medicine, surgery and neuroscience, university of Siena and Fondazione Umberto di Mario-Toscana life science, Viale Bracci 18, 53100 Siena, Italy
| | - E Santini
- Department of clinical and experimental medicine, university of Pisa, Pisa, Italy
| | - C Rossi
- Department of clinical and experimental medicine, university of Pisa, Pisa, Italy
| | - F Dotta
- Department of medicine, surgery and neuroscience, university of Siena and Fondazione Umberto di Mario-Toscana life science, Viale Bracci 18, 53100 Siena, Italy.
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Manell H, Staaf J, Manukyan L, Kristinsson H, Cen J, Stenlid R, Ciba I, Forslund A, Bergsten P. Altered Plasma Levels of Glucagon, GLP-1 and Glicentin During OGTT in Adolescents With Obesity and Type 2 Diabetes. J Clin Endocrinol Metab 2016; 101:1181-9. [PMID: 26745255 DOI: 10.1210/jc.2015-3885] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
CONTEXT Proglucagon-derived hormones are important for glucose metabolism, but little is known about them in pediatric obesity and type 2 diabetes mellitus (T2DM). OBJECTIVE Fasting and postprandial levels of proglucagon-derived peptides glucagon, GLP-1, and glicentin in adolescents with obesity across the glucose tolerance spectrum were investigated. DESIGN This was a cross-sectional study with plasma hormone levels quantified at fasting and during an oral glucose tolerance test (OGTT). SETTING This study took place in a pediatric obesity clinic at Uppsala University Hospital, Sweden. PATIENTS AND PARTICIPANTS Adolescents with obesity, age 10-18 years, with normal glucose tolerance (NGT, n = 23), impaired glucose tolerance (IGT, n = 19), or T2DM (n = 4) and age-matched lean adolescents (n = 19) were included. MAIN OUTCOME MEASURES Outcome measures were fasting and OGTT plasma levels of insulin, glucagon, active GLP-1, and glicentin. RESULTS Adolescents with obesity and IGT had lower fasting GLP-1 and glicentin levels than those with NGT (0.25 vs 0.53 pM, P < .05; 18.2 vs 23.6 pM, P < .01) and adolescents with obesity and T2DM had higher fasting glucagon levels (18.1 vs 10.1 pM, P < .01) than those with NGT. During OGTT, glicentin/glucagon ratios were lower in adolescents with obesity and NGT than in lean adolescents (P < .01) and even lower in IGT (P < .05) and T2DM (P < .001). CONCLUSIONS Obese adolescents with IGT have lowered fasting GLP-1 and glicentin levels. In T2DM, fasting glucagon levels are elevated, whereas GLP-1 and glicentin levels are maintained low. During OGTT, adolescents with obesity have more products of pancreatically than intestinally cleaved proglucagon (ie, more glucagon and less GLP-1) in the plasma. This shift becomes more pronounced when glucose tolerance deteriorates.
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Affiliation(s)
- Hannes Manell
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Johan Staaf
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Levon Manukyan
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Hjalti Kristinsson
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Jing Cen
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Rasmus Stenlid
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Iris Ciba
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Anders Forslund
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
| | - Peter Bergsten
- Department of Medical Cell Biology (H.M., J.S., L.M., H.K., J.C., R.S., P.B.), Uppsala University, 75123 Uppsala, Sweden; Department of Women's and Children's Health (H.M., J.S., J.C., R.S., I.C., A.F.), Uppsala University Hospital, Uppsala, Sweden
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10
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Dusaulcy R, Handgraaf S, Heddad-Masson M, Visentin F, Vesin C, Reimann F, Gribble F, Philippe J, Gosmain Y. α-Cell Dysfunctions and Molecular Alterations in Male Insulinopenic Diabetic Mice Are Not Completely Corrected by Insulin. Endocrinology 2016; 157:536-47. [PMID: 26696123 PMCID: PMC7228809 DOI: 10.1210/en.2015-1725] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Glucagon and α-cell dysfunction are critical in the development of hyperglycemia during diabetes both in humans and rodents. We hypothesized that α-cell dysfunction leading to dysregulated glucagon secretion in diabetes is due to both a lack of insulin and intrinsic defects. To characterize α-cell dysfunction in diabetes, we used glucagon-Venus transgenic male mice and induced insulinopenic hyperglycemia by streptozotocin administration leading to alterations of glucagon secretion. We investigated the in vivo impact of insulinopenic hyperglycemia on glucagon-producing cells using FACS-sorted α-cells from control and diabetic mice. We demonstrate that increased glucagonemia in diabetic mice is mainly due to increases of glucagon release and biosynthesis per cell compared with controls without changes in α-cell mass. We identified genes coding for proteins involved in glucagon biosynthesis and secretion, α-cell differentiation, and potential stress markers such as the glucagon, Arx, MafB, cMaf, Brain4, Foxa1, Foxa3, HNF4α, TCF7L2, Glut1, Sglt2, Cav2.1, Cav2.2, Nav1.7, Kir6.2/Sur1, Pten, IR, NeuroD1, GPR40, and Sumo1 genes, which were abnormally regulated in diabetic mice. Importantly, insulin treatment partially corrected α-cell function and expression of genes coding for proglucagon, or involved in glucagon secretion, glucose transport and insulin signaling but not those coding for cMAF, FOXA1, and α-cell differentiation markers as well as GPR40, NEUROD1, CAV2.1, and SUMO1. Our results indicate that insulinopenic diabetes induce marked α-cell dysfunction and molecular alteration, which are only partially corrected by in vivo insulin treatment.
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Affiliation(s)
- Rodolphe Dusaulcy
- Molecular Diabetes Laboratory, Division of Endocrinology-Diabetes-Hypertension and Nutrition, University Hospital/University of Geneva Medical School, Geneva, Switzerland
| | - Sandra Handgraaf
- Molecular Diabetes Laboratory, Division of Endocrinology-Diabetes-Hypertension and Nutrition, University Hospital/University of Geneva Medical School, Geneva, Switzerland
| | - Mounia Heddad-Masson
- Molecular Diabetes Laboratory, Division of Endocrinology-Diabetes-Hypertension and Nutrition, University Hospital/University of Geneva Medical School, Geneva, Switzerland
| | - Florian Visentin
- Molecular Diabetes Laboratory, Division of Endocrinology-Diabetes-Hypertension and Nutrition, University Hospital/University of Geneva Medical School, Geneva, Switzerland
| | - Christian Vesin
- Department of Cell Physiology and Metabolism, University of Geneva School of Medicine, 1211 Geneva, Switzerland
| | - Franck Reimann
- Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Addenbrooke’s Hospital, cambridge, U.K
| | - Fiona Gribble
- Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Addenbrooke’s Hospital, cambridge, U.K
| | - Jacques Philippe
- Molecular Diabetes Laboratory, Division of Endocrinology-Diabetes-Hypertension and Nutrition, University Hospital/University of Geneva Medical School, Geneva, Switzerland
| | - Yvan Gosmain
- Molecular Diabetes Laboratory, Division of Endocrinology-Diabetes-Hypertension and Nutrition, University Hospital/University of Geneva Medical School, Geneva, Switzerland
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11
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Vasu S, Moffett RC, McClenaghan NH, Flatt PR. Differential molecular and cellular responses of GLP-1 secreting L-cells and pancreatic alpha cells to glucotoxicity and lipotoxicity. Exp Cell Res 2015; 336:100-8. [DOI: 10.1016/j.yexcr.2015.05.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/25/2015] [Accepted: 05/26/2015] [Indexed: 12/25/2022]
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12
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Sangan CB, Jover R, Heimberg H, Tosh D. In vitro reprogramming of pancreatic alpha cells towards a beta cell phenotype following ectopic HNF4α expression. Mol Cell Endocrinol 2015; 399:50-9. [PMID: 25224487 DOI: 10.1016/j.mce.2014.09.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 08/21/2014] [Accepted: 09/09/2014] [Indexed: 12/31/2022]
Abstract
There is currently a shortage of organ donors available for pancreatic beta cell transplantation into diabetic patients. An alternative source of beta cells is pre-existing pancreatic cells. While we know that beta cells can arise directly from alpha cells during pancreatic regeneration we do not understand the molecular basis for the switch in phenotype. The aim of the present study was to investigate if hepatocyte nuclear factor 4 alpha (HNF4α), a transcription factor essential for a normal beta cell phenotype, could induce the reprogramming of alpha cells towards potential beta cells. We utilised an in vitro model of pancreatic alpha cells, the murine αTC1-9 cell line. We initially characterised the αTC1-9 cell line before and following adenovirus-mediated ectopic expression of HNF4α. We analysed the phenotype at transcript and protein level and assessed its glucose-responsiveness. Ectopic HNF4α expression in the αTC1-9 cell line induced a change in morphology (1.7-fold increase in size), suppressed glucagon expression, induced key beta cell-specific markers (insulin, C-peptide, glucokinase, GLUT2 and Pax4) and pancreatic polypeptide (PP) and enabled the cells to secrete insulin in a glucose-regulated manner. In conclusion, HNF4α reprograms alpha cells to beta-like cells.
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Affiliation(s)
| | - Ramiro Jover
- Experimental Hepatology Unit. Hosp. La Fe & Dep. Biochemistry, University of Valencia. CIBERehd, Spain
| | - Harry Heimberg
- Diabetes Research Center, Vrije Universiteit Brussel, Brussels, Belgium
| | - David Tosh
- Centre for Regenerative Medicine, University of Bath, Bath, UK.
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13
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Boyda HN, Procyshyn RM, Pang CCY, Barr AM. Peripheral adrenoceptors: the impetus behind glucose dysregulation and insulin resistance. J Neuroendocrinol 2013; 25:217-28. [PMID: 23140239 DOI: 10.1111/jne.12002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/10/2012] [Accepted: 11/04/2012] [Indexed: 12/20/2022]
Abstract
It is now accepted that several pharmacological drug treatments trigger clinical manifestations of glucose dysregulation, such as hyperglycaemia, glucose intolerance and insulin resistance, in part through poorly understood mechanisms. Persistent sympathoadrenal activation is linked to glucose dysregulation and insulin resistance, both of which significantly increase the risk of emergent endocrinological disorders, including metabolic syndrome and type 2 diabetes mellitus. Through the use of targeted mutagenesis and pharmacological methods, preclinical and clinical research has confirmed physiological glucoregulatory roles for several peripheral α- and β-adrenoceptor subtypes. Adrenoceptor isoforms in the pancreas (α(2A) and β(2) ), skeletal muscle (α(1A) and β(2) ), liver (α(1A & B) and β(2) ) and adipose tissue (α(1A) and β(1 & 3) ) are convincing aetiological targets that account for both immediate and long-lasting alterations in blood glucose homeostasis. Because significant overlap exists between the therapeutic applications of numerous classes of drugs and their associated adverse side-effects, a better understanding of peripheral adrenoceptor-mediated glucose metabolism is thus warranted. Therefore, at the same time as providing a brief review of glucose homeostasis in the periphery, the present review addresses both functional and pathophysiological roles of the mammalian α(1) , α(2) , and β-adrenoceptor isoforms in whole-body glucose turnover. We highlight evidence relating to the clinical use of common adrenergic drugs and their impacts on glucose metabolism.
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Affiliation(s)
- H N Boyda
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada.
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