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Roberts FL, Cataldo LR, Fex M. Monoamines' role in islet cell function and type 2 diabetes risk. Trends Mol Med 2023; 29:1045-1058. [PMID: 37722934 DOI: 10.1016/j.molmed.2023.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/22/2023] [Accepted: 08/25/2023] [Indexed: 09/20/2023]
Abstract
The two monoamines serotonin and melatonin have recently been highlighted as potent regulators of islet hormone secretion and overall glucose homeostasis in the body. In fact, dysregulated signaling of both amines are implicated in β-cell dysfunction and development of type 2 diabetes mellitus (T2DM). Serotonin is a key player in β-cell physiology and plays a role in expansion of β-cell mass. Melatonin regulates circadian rhythm and nutrient metabolism and reduces insulin release in human and rodent islets in vitro. Herein, we focus on the role of serotonin and melatonin in islet physiology and the pathophysiology of T2DM. This includes effects on hormone secretion, receptor expression, genetic variants influencing β-cell function, melatonin treatment, and compounds that alter serotonin availability and signaling.
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Affiliation(s)
- Fiona Louise Roberts
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit for Molecular Metabolism, SE-21428 Malmö, Sweden
| | - Luis Rodrigo Cataldo
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit for Molecular Metabolism, SE-21428 Malmö, Sweden; The Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Malin Fex
- Lund University Diabetes Centre, Department of Clinical Sciences, Unit for Molecular Metabolism, SE-21428 Malmö, Sweden.
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Gheibi S, Cataldo LR, Hamilton A, Huang M, Kalamajski S, Fex M, Mulder H. Reduced Expression Level of Protein Phosphatase PPM1E Serves to Maintain Insulin Secretion in Type 2 Diabetes. Diabetes 2023; 72:455-466. [PMID: 36662636 DOI: 10.2337/db22-0472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 01/12/2023] [Indexed: 01/21/2023]
Abstract
Reversible phosphorylation is an important regulatory mechanism. Regulation of protein phosphorylation in β-cells has been extensively investigated, but less is known about protein dephosphorylation. To understand the role of protein dephosphorylation in β-cells and type 2 diabetes (T2D), we first examined mRNA expression of the type 2C family (PP2C) of protein phosphatases in islets from T2D donors. Phosphatase expression overall was changed in T2D, and that of PPM1E was the most markedly downregulated. PPM1E expression correlated inversely with HbA1c. Silencing of PPM1E increased glucose-stimulated insulin secretion (GSIS) in INS-1 832/13 cells and/or islets from patients with T2D, whereas PPM1E overexpression decreased GSIS. Increased GSIS after PPM1E silencing was associated with decreased oxidative stress, elevated cytosolic Ca2+ levels and ATP to ADP ratio, increased hyperpolarization of the inner mitochondrial membrane, and phosphorylation of CaMKII, AMPK, and acetyl-CoA carboxylase. Silencing of PPM1E, however, did not change insulin content. Increased GSIS, cell viability, and activation of AMPK upon metformin treatment in β-cells were observed upon PPM1E silencing. Thus, protein dephosphorylation via PPM1E abrogates GSIS. Consequently, reduced PPM1E expression in T2D may be a compensatory response of β-cells to uphold insulin secretion under metabolic duress. Targeting PPM1E in β-cells may thus represent a novel therapeutic strategy for treatment of T2D.
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Affiliation(s)
- Sevda Gheibi
- Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmö, Sweden
| | - Luis Rodrigo Cataldo
- Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmö, Sweden
- The Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Hamilton
- Unit of Islet Cell Exocytosis, Lund University Diabetes Centre, Malmö, Sweden
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Mi Huang
- Department of Clinical Sciences, Genetic and Molecular Epidemiology Unit, Lund University, Malmö, Sweden
| | - Sebastian Kalamajski
- Department of Clinical Sciences, Genetic and Molecular Epidemiology Unit, Lund University, Malmö, Sweden
| | - Malin Fex
- Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmö, Sweden
| | - Hindrik Mulder
- Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmö, Sweden
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Bacos K, Perfilyev A, Karagiannopoulos A, Cowan E, Ofori JK, Bertonnier-Brouty L, Rönn T, Lindqvist A, Luan C, Ruhrmann S, Ngara M, Nilsson Å, Gheibi S, Lyons CL, Lagerstedt JO, Barghouth M, Esguerra JL, Volkov P, Fex M, Mulder H, Wierup N, Krus U, Artner I, Eliasson L, Prasad RB, Cataldo LR, Ling C. Type 2 diabetes candidate genes, including PAX5, cause impaired insulin secretion in human pancreatic islets. J Clin Invest 2023; 133:163612. [PMID: 36656641 PMCID: PMC9927941 DOI: 10.1172/jci163612] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
Type 2 diabetes (T2D) is caused by insufficient insulin secretion from pancreatic β cells. To identify candidate genes contributing to T2D pathophysiology, we studied human pancreatic islets from approximately 300 individuals. We found 395 differentially expressed genes (DEGs) in islets from individuals with T2D, including, to our knowledge, novel (OPRD1, PAX5, TET1) and previously identified (CHL1, GLRA1, IAPP) candidates. A third of the identified expression changes in islets may predispose to diabetes, as expression of these genes associated with HbA1c in individuals not previously diagnosed with T2D. Most DEGs were expressed in human β cells, based on single-cell RNA-Seq data. Additionally, DEGs displayed alterations in open chromatin and associated with T2D SNPs. Mouse KO strains demonstrated that the identified T2D-associated candidate genes regulate glucose homeostasis and body composition in vivo. Functional validation showed that mimicking T2D-associated changes for OPRD1, PAX5, and SLC2A2 impaired insulin secretion. Impairments in Pax5-overexpressing β cells were due to severe mitochondrial dysfunction. Finally, we discovered PAX5 as a potential transcriptional regulator of many T2D-associated DEGs in human islets. Overall, we have identified molecular alterations in human pancreatic islets that contribute to β cell dysfunction in T2D pathophysiology.
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Affiliation(s)
- Karl Bacos
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | | | - Alexandros Karagiannopoulos
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Elaine Cowan
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Jones K. Ofori
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Ludivine Bertonnier-Brouty
- Endocrine Cell Differentiation, Department of Laboratory Medicine, Lund Stem Cell Center, Malmö, Scania, Sweden
| | - Tina Rönn
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Andreas Lindqvist
- Neuroendocrine Cell Biology, Department of Experimental Medical Science
| | - Cheng Luan
- Unit of Islet Pathophysiology, Department of Clinical Sciences
| | - Sabrina Ruhrmann
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Mtakai Ngara
- Neuroendocrine Cell Biology, Department of Experimental Medical Science
| | - Åsa Nilsson
- Human Tissue Lab, Department of Clinical Sciences
| | - Sevda Gheibi
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Claire L. Lyons
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Jens O. Lagerstedt
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | | | - Jonathan L.S. Esguerra
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Petr Volkov
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
| | - Malin Fex
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Hindrik Mulder
- Molecular Metabolism Unit, Department of Clinical Sciences, and
| | - Nils Wierup
- Neuroendocrine Cell Biology, Department of Experimental Medical Science
| | - Ulrika Krus
- Human Tissue Lab, Department of Clinical Sciences
| | - Isabella Artner
- Endocrine Cell Differentiation, Department of Laboratory Medicine, Lund Stem Cell Center, Malmö, Scania, Sweden
| | - Lena Eliasson
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden
| | - Rashmi B. Prasad
- Genomics, Diabetes and Endocrinology, Department of Clinical Sciences, Lund University Diabetes Centre, Scania University Hospital, Malmö, Scania, Sweden.,Institute of Molecular Medicine (FIMM), Helsinki University, Helsinki, Finland
| | - Luis Rodrigo Cataldo
- Molecular Metabolism Unit, Department of Clinical Sciences, and,The Novo Nordisk Foundation Centre for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Ling
- Epigenetics and Diabetes Unit, Department of Clinical Sciences and
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Cataldo LR, Singh T, Achanta K, Bsharat S, Prasad RB, Luan C, Renström E, Eliasson L, Artner I. MAFA and MAFB regulate exocytosis-related genes in human β-cells. Acta Physiol (Oxf) 2022; 234:e13761. [PMID: 34978761 DOI: 10.1111/apha.13761] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/22/2021] [Accepted: 01/01/2022] [Indexed: 12/13/2022]
Abstract
AIMS Reduced expression of exocytotic genes is associated with functional defects in insulin exocytosis contributing to impaired insulin secretion and type 2 diabetes (T2D) development. MAFA and MAFB transcription factors regulate β-cell physiology, and their gene expression is reduced in T2D β cells. We investigate if loss of MAFA and MAFB in human β cells contributes to T2D progression by regulating genes required for insulin exocytosis. METHODS Three approaches were performed: (1) RNAseq analysis with the focus on exocytosis-related genes in MafA-/- mouse islets, (2) correlational analysis between MAFA, MAFB and exocytosis-related genes in human islets and (3) MAFA and MAFB silencing in human islets and EndoC-βH1 cells followed by functional in vitro studies. RESULTS The expression of 30 exocytosis-related genes was significantly downregulated in MafA-/- mouse islets. In human islets, the expression of 29 exocytosis-related genes correlated positively with MAFA and MAFB. Eight exocytosis-related genes were downregulated in MafA-/- mouse islets and positively correlated with MAFA and MAFB in human islets. From this analysis, the expression of RAB3A, STXBP1, UNC13A, VAMP2, NAPA, NSF, STX1A and SYT7 was quantified after acute MAFA or MAFB silencing in EndoC-βH1 cells and human islets. MAFA and MAFB silencing resulted in impaired insulin secretion and reduced STX1A, SYT7 and STXBP1 (EndoC-βH1) and STX1A (human islets) mRNA expression. STX1A and STXBP1 protein expression was also impaired in islets from T2D donors which lack MAFA expression. CONCLUSION Our data indicate that STXBP1 and STX1A are important MAFA/B-regulated exocytosis genes which may contribute to insulin exocytosis defects observed in MAFA-deficient human T2D β cells.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Endocrine Cell Differentiation and Function Group Stem Cell Centre Lund University Lund Sweden
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
- The Novo Nordisk Foundation Centre for Basic Metabolic Research Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Tania Singh
- Endocrine Cell Differentiation and Function Group Stem Cell Centre Lund University Lund Sweden
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
| | - Kavya Achanta
- Endocrine Cell Differentiation and Function Group Stem Cell Centre Lund University Lund Sweden
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
| | - Sara Bsharat
- Endocrine Cell Differentiation and Function Group Stem Cell Centre Lund University Lund Sweden
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
| | - Rashmi B. Prasad
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
- Department of Clinical Sciences in Malmö Malmo Sweden
| | - Cheng Luan
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
| | - Erik Renström
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
| | - Lena Eliasson
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
- Department of Clinical Sciences in Malmö Malmo Sweden
- Islet Cell Exocytosis Lund University Lund Sweden
| | - Isabella Artner
- Endocrine Cell Differentiation and Function Group Stem Cell Centre Lund University Lund Sweden
- Lund University Diabetes Centre Clinical Research Center Malmo Sweden
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Cataldo LR, Vishnu N, Singh T, Bertonnier-Brouty L, Bsharat S, Luan C, Renström E, Prasad RB, Fex M, Mulder H, Artner I. The MafA-target gene PPP1R1A regulates GLP1R-mediated amplification of glucose-stimulated insulin secretion in β-cells. Metabolism 2021; 118:154734. [PMID: 33631146 DOI: 10.1016/j.metabol.2021.154734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/07/2021] [Accepted: 02/15/2021] [Indexed: 12/11/2022]
Abstract
The amplification of glucose-stimulated insulin secretion (GSIS) through incretin signaling is critical for maintaining physiological glucose levels. Incretins, like glucagon-like peptide 1 (GLP1), are a target of type 2 diabetes drugs aiming to enhance insulin secretion. Here we show that the protein phosphatase 1 inhibitor protein 1A (PPP1R1A), is expressed in β-cells and that its expression is reduced in dysfunctional β-cells lacking MafA and upon acute MafA knock down. MafA is a central regulator of GSIS and β-cell function. We observed a strong correlation of MAFA and PPP1R1A mRNA levels in human islets, moreover, PPP1R1A mRNA levels were reduced in type 2 diabetic islets and positively correlated with GLP1-mediated GSIS amplification. PPP1R1A silencing in INS1 (832/13) β-cells impaired GSIS amplification, PKA-target protein phosphorylation, mitochondrial coupling efficiency and also the expression of critical β-cell marker genes like MafA, Pdx1, NeuroD1 and Pax6. Our results demonstrate that the β-cell transcription factor MafA is required for PPP1R1A expression and that reduced β-cell PPP1R1A levels impaired β-cell function and contributed to β-cell dedifferentiation during type 2 diabetes. Loss of PPP1R1A in type 2 diabetic β-cells may explains the unresponsiveness of type 2 diabetic patients to GLP1R-based treatments.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Endocrine Cell Differentiation and Function group, Stem Cell Centre, Lund University, Sweden; Lund University Diabetes Centre, Clinical Research Center, Sweden.
| | - Neelanjan Vishnu
- Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Tania Singh
- Endocrine Cell Differentiation and Function group, Stem Cell Centre, Lund University, Sweden; Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Ludivine Bertonnier-Brouty
- Endocrine Cell Differentiation and Function group, Stem Cell Centre, Lund University, Sweden; Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Sara Bsharat
- Endocrine Cell Differentiation and Function group, Stem Cell Centre, Lund University, Sweden; Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Cheng Luan
- Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Erik Renström
- Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Rashmi B Prasad
- Lund University Diabetes Centre, Clinical Research Center, Sweden; Department of Clinical Sciences in Malmö, Sweden
| | - Malin Fex
- Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Hindrik Mulder
- Lund University Diabetes Centre, Clinical Research Center, Sweden
| | - Isabella Artner
- Endocrine Cell Differentiation and Function group, Stem Cell Centre, Lund University, Sweden; Lund University Diabetes Centre, Clinical Research Center, Sweden.
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Santos JL, Krause BJ, Cataldo LR, Vega J, Salas-Pérez F, Mennickent P, Gallegos R, Milagro FI, Prieto-Hontoria P, Riezu-Boj JI, Bravo C, Salas-Huetos A, Arpón A, Galgani JE, Martínez JA. PPARGC1A Gene Promoter Methylation as a Biomarker of Insulin Secretion and Sensitivity in Response to Glucose Challenges. Nutrients 2020; 12:nu12092790. [PMID: 32933059 PMCID: PMC7551463 DOI: 10.3390/nu12092790] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 12/15/2022] Open
Abstract
Methylation in CpG sites of the PPARGC1A gene (encoding PGC1-α) has been associated with adiposity, insulin secretion/sensitivity indexes and type 2 diabetes. We assessed the association between the methylation profile of the PPARGC1A gene promoter gene in leukocytes with insulin secretion/sensitivity indexes in normoglycemic women. A standard oral glucose tolerance test (OGTT) and an abbreviated version of the intravenous glucose tolerance test (IVGTT) were carried out in n = 57 Chilean nondiabetic women with measurements of plasma glucose, insulin, and C-peptide. Bisulfite-treated DNA from leukocytes was evaluated for methylation levels in six CpG sites of the proximal promoter of the PPARGC1A gene by pyrosequencing (positions -816, -783, -652, -617, -521 and -515). A strong correlation between the DNA methylation percentage of different CpG sites of the PPARGC1A promoter in leukocytes was found, suggesting an integrated epigenetic control of this region. We found a positive association between the methylation levels of the CpG site -783 with the insulin sensitivity Matsuda composite index (rho = 0.31; p = 0.02) derived from the OGTT. The CpG hypomethylation in the promoter position -783 of the PPARGC1A gene in leukocytes may represent a biomarker of reduced insulin sensitivity after the ingestion of glucose.
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Affiliation(s)
- José L. Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
- Correspondence: ; Tel.: +56-2-354-3862; Fax: +56-2-633-8298
| | - Bernardo J. Krause
- Instituto de Ciencias de la Salud, Universidad de O’Higgins, Avenida Libertador Bernardo O’Higgins 611, Rancagua 2841935, Chile; (B.J.K.); (F.S.-P.)
| | - Luis Rodrigo Cataldo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
| | - Javier Vega
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
| | - Francisca Salas-Pérez
- Instituto de Ciencias de la Salud, Universidad de O’Higgins, Avenida Libertador Bernardo O’Higgins 611, Rancagua 2841935, Chile; (B.J.K.); (F.S.-P.)
- Department of Nutrition, Food Sciences and Physiology, Centre for Nutrition Research, University of Navarra, 31008 Pamplona, Spain; (F.I.M.); (J.I.R.-B.); (A.A.); (J.A.M.)
| | - Paula Mennickent
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
| | - Raúl Gallegos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
| | - Fermín I. Milagro
- Department of Nutrition, Food Sciences and Physiology, Centre for Nutrition Research, University of Navarra, 31008 Pamplona, Spain; (F.I.M.); (J.I.R.-B.); (A.A.); (J.A.M.)
- Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 28029 Madrid, Spain
- IdiSNA, Navarra’s Health Research Institute, 31008 Pamplona, Spain
| | | | - J. Ignacio Riezu-Boj
- Department of Nutrition, Food Sciences and Physiology, Centre for Nutrition Research, University of Navarra, 31008 Pamplona, Spain; (F.I.M.); (J.I.R.-B.); (A.A.); (J.A.M.)
- IdiSNA, Navarra’s Health Research Institute, 31008 Pamplona, Spain
| | - Carolina Bravo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
| | - Albert Salas-Huetos
- Andrology and IVF Laboratory, Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT 84108, USA;
| | - Ana Arpón
- Department of Nutrition, Food Sciences and Physiology, Centre for Nutrition Research, University of Navarra, 31008 Pamplona, Spain; (F.I.M.); (J.I.R.-B.); (A.A.); (J.A.M.)
| | - José E. Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile; (L.R.C.); (J.V.); (P.M.); (R.G.); (C.B.); (J.E.G.)
- Departamento de Ciencias de la Salud, Nutrición y Dietética, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 781000, Chile
| | - J. Alfredo Martínez
- Department of Nutrition, Food Sciences and Physiology, Centre for Nutrition Research, University of Navarra, 31008 Pamplona, Spain; (F.I.M.); (J.I.R.-B.); (A.A.); (J.A.M.)
- Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 28029 Madrid, Spain
- IdiSNA, Navarra’s Health Research Institute, 31008 Pamplona, Spain
- IMDEA-Food, 28049 Madrid, Spain
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Cataldo LR, Suazo J, Olmos P, Bravo C, Galgani JE, Fex M, Martínez JA, Santos JL. Platelet Serotonin Levels Are Associated with Plasma Soluble Leptin Receptor Concentrations in Normoglycemic Women. J Diabetes Res 2019; 2019:2714049. [PMID: 31192261 PMCID: PMC6525868 DOI: 10.1155/2019/2714049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/25/2019] [Indexed: 02/07/2023] Open
Abstract
Most peripheral serotonin (5-hydroxytryptamine (5HT)) is synthetized in the gut with platelets being its main circulating reservoir. 5HT is acting as a hormone in key organs to regulate glucose and lipid metabolism. However, the relation between platelet 5HT levels and traits related to glucose homeostasis and lipid metabolism in humans remains poorly explored. The objectives of this study were (a) to assess the association between platelet 5HT levels and plasma concentration of nonesterified fatty acids (NEFAs) and some adipokines including leptin and its soluble leptin receptor (sOb-R), (b) to assess the association between platelet 5HT levels and anthropometric traits and indexes of insulin secretion/sensitivity derived from oral glucose tolerance test (OGTT), and (c) to evaluate changes in platelet 5HT levels in response to OGTT. In a cross-sectional study, 59 normoglycemic women underwent a standard 2-hour OGTT. Plasma leptin, sOb-R, total and high molecular weight adiponectin, TNFα, and MCP1 were determined by immunoassays. Platelet 5HT levels and NEFAs were measured before and after OGTT. The free leptin index was calculated from leptin and sOb-R measurements. Insulin sensitivity indexes derived from OGTT (HOMA-S and Matsuda ISICOMP) and plasma NEFAs (Adipose-IR, Revised QUICKI) were also calculated. Our data show that among metabolic traits, platelet 5HT levels were associated with plasma sOb-R (r = 0.39, p = 0.003, corrected p = 0.018). Platelet 5HT levels were reduced in response to OGTT (779 ± 237 vs.731 ± 217 ng/109 platelets, p = 0.005). In conclusion, platelet 5HT levels are positively associated with plasma sOb-R concentrations and reduced in response to glucose intake possibly indicating a role of peripheral 5HT in leptin-mediated appetite regulation.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Lund University Diabetes Centre, Clinical Research Center, Lund University, Malmö, Sweden
| | - José Suazo
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile, Santiago, Chile
| | - Pablo Olmos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carolina Bravo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - José E. Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Department of Health Sciences, Nutrition & Dietetics, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Malin Fex
- Lund University Diabetes Centre, Clinical Research Center, Lund University, Malmö, Sweden
| | - J. Alfredo Martínez
- Department of Nutrition, Food Sciences and Physiology, Centre for Nutrition Research, University of Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- Navarra's Health Research Institute (IdiSNA), Pamplona, Spain
- IMDEA-Food, Madrid, Spain
| | - José L. Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
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Cataldo LR, Fernández-Verdejo R, Santos JL, Galgani JE. Plasma MOTS-c levels are associated with insulin sensitivity in lean but not in obese individuals. J Investig Med 2018; 66:1019-1022. [PMID: 29593067 DOI: 10.1136/jim-2017-000681] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2018] [Indexed: 11/03/2022]
Abstract
Mitochondrial open reading frame of the 12S rRNA-c (MOTS-c) is a mitochondrial-derived peptide that attenuates weight gain and hyperinsulinemia when administered to high fat-fed mice. MOTS-c is therefore a potential regulator of metabolic homeostasis under conditions of high-energy supply. However, the effect of insulin resistance and obesity on plasma MOTS-c concentration in humans is unknown. To gain insight into MOTS-c regulation, we measured plasma MOTS-c concentration and analyzed its relationship with insulin sensitivity surrogates, in lean and obese humans (n=10 per group). Obese individuals had impaired insulin sensitivity as indicated by low Matsuda and high Homeostatic Model Assessment (HOMA) indexes. Although plasma MOTS-c concentration was similar in lean and obese individuals (0.48±0.16 and 0.52±0.15 ng/mL; p=0.60), it was correlated with HOMA (r=0.53; p<0.05) and Matsuda index (r=-0.46; p<0.05). Notably, when the groups were analyzed separately, the associations remained only in lean individuals. We conclude that plasma MOTS-c concentration is unaltered in human obesity. However, MOTS-c associates positively with insulin resistance mostly in lean individuals, indicating that plasma MOTS-c concentration depends on the metabolic status in this population. Such dependence seems altered when obesity settles. The implications of plasma MOTS-c for human metabolic homeostasis deserve future examination.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo Fernández-Verdejo
- Carrera de Nutrición y Dietética, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - José Luis Santos
- Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jose Eduardo Galgani
- Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Carrera de Nutrición y Dietética, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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Bravo C, Cataldo LR, Galgani J, Parada J, Santos JL. Leptin/Adiponectin Ratios Using Either Total Or High-Molecular-Weight Adiponectin as Biomarkers of Systemic Insulin Sensitivity in Normoglycemic Women. J Diabetes Res 2017; 2017:9031079. [PMID: 28626772 PMCID: PMC5463152 DOI: 10.1155/2017/9031079] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/13/2017] [Indexed: 01/25/2023] Open
Abstract
Plasma leptin/adiponectin ratio (LAR) is negatively associated with insulin sensitivity indexes. High-molecular-weight adiponectin (HMWA) was proposed as the most biologically active form of this insulin-sensitizing adipokine. There are no studies assessing the relative merits of leptin/HMWA ratio over LAR as a biomarker of systemic insulin sensitivity. A standard 2-hour oral glucose tolerance test (OGTT; 75 g of glucose) and a short minimal-model intravenous glucose tolerance test (IVGTT; 0.3 g/kg body weight) were performed in 58 Chilean normoglycemic women (age: 27 ± 6.3 years, BMI 23.6 ± 3.2 kg/m2). LAR was negatively associated with HOMA-S (r = -0.49; p < 0.0001), Matsuda-ISICOMP (r = -0.54; p < 0.0001), and the calculated sensitivity index (CSi) derived from IVGTT (r = -0.38; p = 0.007). In comparison to LAR, leptin/HMWA ratio did not increase neither the linear fit (r2) nor the magnitude of association with insulin sensitivity indexes (slope of multiple linear regression). The discriminatory capacity of both ratios to classify insulin-resistant versus insulin-sensitive subjects was similar for HOMA-S (p = 0.84), Matsuda-ISICOMP (p = 0.43), or CSi (p = 0.50). In conclusion, LAR showed consistent negative associations with different systemic insulin sensitivity indexes. The use of HMWA to generate leptin/HMWA ratio did not show any advantage over LAR as a biomarker of systemic insulin sensitivity in normoglycemic women.
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Affiliation(s)
- Carolina Bravo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Luis Rodrigo Cataldo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - José Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Carrera de Nutrición y Dietética, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Javier Parada
- School of Food Engineering, Universidad Austral de Chile, Valdivia, Chile
| | - José Luis Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
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Cataldo LR, Mizgier ML, Bravo Sagua R, Jaña F, Cárdenas C, Llanos P, Busso D, Olmos P, Galgani JE, Santos JL, Cortés VA. Prolonged Activation of the Htr2b Serotonin Receptor Impairs Glucose Stimulated Insulin Secretion and Mitochondrial Function in MIN6 Cells. PLoS One 2017; 12:e0170213. [PMID: 28129327 PMCID: PMC5271329 DOI: 10.1371/journal.pone.0170213] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/02/2017] [Indexed: 11/23/2022] Open
Abstract
Aims Pancreatic β-cells synthesize and release serotonin (5 hydroxytryptamine, 5HT); however, the role of 5HT receptors on glucose stimulated insulin secretion (GSIS) and the mechanisms mediating this function is not fully understood. The aims of this study were to determine the expression profile of 5HT receptors in murine MIN6 β-cells and to examine the effects of pharmacological activation of 5HT receptor Htr2b on GSIS and mitochondrial function. Materials and Methods mRNA levels of 5HT receptors in MIN6 cells were quantified by RT qPCR. GSIS was assessed in MIN6 cells in response to global serotonergic activation with 5HT and pharmacological Htr2b activation or inhibition with BW723C86 or SB204741, respectively. In response to Htr2b activation also was evaluated the mRNA and protein levels of PGC1α and PPARy by RT-qPCR and western blotting and mitochondrial function by oxygen consumption rate (OCR) and ATP cellular content. Results We found that mRNA levels of most 5HT receptors were either very low or undetectable in MIN6 cells. By contrast, Htr2b mRNA was present at moderate levels in these cells. Preincubation (6 h) of MIN6 cells with 5HT or BW723C86 reduced GSIS and the effect of 5HT was prevented by SB204741. Preincubation with BW723C86 increased PGC1α and PPARy mRNA and protein levels and decreased mitochondrial respiration and ATP content in MIN6 cells. Conclusions Our results indicate that prolonged Htr2b activation in murine β-cells decreases glucose-stimulated insulin secretion and mitochondrial activity by mechanisms likely dependent on enhanced PGC1α/PPARy expression.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María L. Mizgier
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Roberto Bravo Sagua
- Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
| | - Fabián Jaña
- Anatomy and Developmental Biology Program, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - César Cárdenas
- Anatomy and Developmental Biology Program, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
- Geroscience Center for Brain Health and Metabolism, Santiago, Chile
- Buck Institute for Research on Aging, Novato, CA, United States of America
| | - Paola Llanos
- Institute for Research in Dental Sciences, School of Odontology, University of Chile, Santiago, Chile
| | - Dolores Busso
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Olmos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - José E. Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- UDA-Health Sciences, Nutrition and Dietetic Program, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - José L. Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Víctor A. Cortés
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
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Santos JL, Yévenes I, Cataldo LR, Morales M, Galgani J, Arancibia C, Vega J, Olmos P, Flores M, Valderas JP, Pollak F. Development and assessment of the disposition index based on the oral glucose tolerance test in subjects with different glycaemic status. J Physiol Biochem 2015; 72:121-31. [PMID: 26660757 DOI: 10.1007/s13105-015-0458-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 11/26/2015] [Indexed: 10/22/2022]
Abstract
Insulin secretion and insulin sensitivity indexes are related by hyperbolic functions, allowing the calculation of the disposition index (DI) as the product of the acute insulin response (AIR) and the insulin sensitivity index (Si) from intravenous glucose tolerance test (IVGTT). Our objective was to develop an oral-DI based on the oral glucose tolerance test (OGTT) and to assess its association with glucose tolerance status. This research is structured in three studies. Study 1: OGTT were performed in 833 non-diabetic Chilean women (18-60 years) without family history of diabetes mellitus. Study 2: an independent group of n = 57 non-diabetic (18-46 years) without family history of diabetes mellitus carried out an OGTT and an abbreviated IVGTT. Study 3: a sample of 1674 Chilean adults (18-60 years) with different glycaemic status performed an OGTT. An adequate statistical fit for a rectangular hyperbola was found between the area under the curve of insulin-to-glucose ratio (AUCI/G-R) and the Matsuda ISI-COMP index (study 1). The oral-DI derived as AUCI/G-R × ISI-COMP was previously termed insulin-secretion-sensitivity index-2 (ISSI-2). ISSI-2 significantly correlated with DI from IVGTT (rho = 0.34; p = 0.009) (study 2). ISSI-2 shows important differences across groups of subjects with different glycaemic status (study 3). We have confirmed that ISSI-2 replicates the mathematical properties of DI, showing significant correlations with DI from the abbreviated MM-IVGTT. These results indicate that ISSI-2 constitutes a surrogate measure of insulin secretion relative to insulin sensitivity and emphasizes the pivotal role of impaired insulin secretion in the development of glucose homeostasis dysregulation.
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Affiliation(s)
- J L Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile.
| | - I Yévenes
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - L R Cataldo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - M Morales
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - J Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - C Arancibia
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - J Vega
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - P Olmos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - M Flores
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - J P Valderas
- Departamento de Ciencias Médicas, Facultad de Medicina Odontología, Universidad de Antofagasta, Antofagasta, Chile
| | - F Pollak
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
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Vega JA, Salazar G, Hodgson MI, Cataldo LR, Valladares M, Obregón AM, Santos JL. Melanocortin-4 Receptor Gene Variation Is Associated with Eating Behavior in Chilean Adults. Ann Nutr Metab 2015; 68:35-41. [PMID: 26588347 DOI: 10.1159/000439092] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/29/2015] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To evaluate the association between allelic variants of melanocortin receptors -3 and -4 (MC3R and MC4R, respectively) and leptin receptor (LEPR) genes with body mass index (BMI) and eating behavior. METHODS We selected 344 Chilean adults (57.8% women; age 39.1 ± 6.6 years) with a wide variation in BMI (30.3 ± 6.3 kg/m²). The Three-Factor Eating Questionnaire-R18 that measures uncontrolled eating (UE), emotional eating (EE) and cognitive restraint scores was adapted, validated and assessed for association with BMI. Genotypes were determined by polymerase chain reaction followed by restriction fragment length polymorphism techniques and Taqman assays. RESULTS Higher EE scores were found in obese vs. non-obese in both men (p = 0.01) and women (p < 0.001). UE scores were significantly associated with BMI only in women (p = 0.002). No significant differences in eating behavior scores or BMI were found by LEPR (rs1137101, rs8179183 and rs1137100 polymorphisms) or MC3R (rs3746619 and rs3827103). Carriers of the C allele for MC4R rs17782313 showed significantly higher scores of UE compared to non-carriers (2.3 ± 0.8 vs. 2.0 ± 0.7; p = 0.02). Additionally, we also report a monogenic case of obesity carrying the pathogenic mutation 449C>T (Thr150Ile) in MC4R gene with no apparent alterations in eating behavior scores. CONCLUSIONS UE scores were higher in C-allele carriers of MC4R-rs17782313 compared to non-carriers.
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Affiliation(s)
- Javier A Vega
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Catx00F3;lica de Chile, Santiago, Chile
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Cataldo LR, Cortés VA, Mizgier ML, Aranda E, Mezzano D, Olmos P, Galgani JE, Suazo J, Santos JL. Fluoxetine impairs insulin secretion without modifying extracellular serotonin levels in MIN6 β-cells. Exp Clin Endocrinol Diabetes 2015; 123:473-8. [PMID: 26011169 DOI: 10.1055/s-0035-1549964] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Pancreatic β-cells synthetize and store Serotonin (5-Hydroxytriptamine, 5HT) which is co-released with insulin. It has been proposed that extracellular 5HT binds to specific cell surface receptors and modulate insulin secretion. On the other hand, Selective Serotonin Reuptake Inhibitor (SSRI) fluoxetine seems to reduce Glucose-Stimulated Insulin Secretion (GSIS). However, it is unknown whether this effect results from changes in extracellular 5HT concentration owed to the blockade of 5HT transporter (SERT) or from non-5HT dependent actions. The aims of this work were: 1) to quantify extracellular 5HT levels and GSIS in β-cell lines, 2) to determine whether extracellular 5HT levels and GSIS are changed by fluoxetine or 5-Hydroxytryptophan (5HTP, the immediate 5HT biosynthetic precursor), and 3) to quantify the expression of Slc6a4 gene (encoding SERT) in β-cell lines in relation to other genes involved in 5HT system. MATERIAL AND METHODS β-cell lines MIN6 and RINm5f were subjected to GSIS protocols, after treatment with fluoxetine, 5HTP or 5HT. Insulin and 5HT were quantified by ELISA and HPLC, respectively. Relative mRNA expression was quantified by RT-qPCR. RESULTS MIN6 β-cells secretes 5HT in response to glucose, showing a sharp increase in 5HT release when cells were preloaded with 5HTP. Treatment with 5HT or fluoxetine reduces GSIS. Fluoxetine fails to further increases 5HTP-induced elevation of secreted 5HT. MIN6 β-cells express both isoforms of Tryptophan Hydroxylase (Tph1 and Tph2), and have high expression levels of L-Dopa decarboxylase (Ddc), both enzymes involved in 5HT biosynthetic pathway, but do not express the 5HT transporters Slc6a4 or Slc6a3 (the Dopamine-5HT transporter) genes. CONCLUSION The inhibitory effect of fluoxetine on β-cell glucose stimulated insulin secretion is not mediated by blockage of 5HT transporter through SERT.
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Affiliation(s)
- L R Cataldo
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile
| | - V A Cortés
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile
| | - M L Mizgier
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile
| | - E Aranda
- Laboratorio de Hemostasia, School of Medicine, Pontificia Universidad Católica de Chile
| | - D Mezzano
- Laboratorio de Hemostasia, School of Medicine, Pontificia Universidad Católica de Chile
| | - P Olmos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile
| | - J E Galgani
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile
| | - J Suazo
- Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile
| | - J L Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile
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Cataldo LR, Cortés VA, Galgani JE, Olmos PR, Santos JL. [Role of peripheral serotonin in the insulin secretion and glucose homeostasis]. NUTR HOSP 2014; 30:498-508. [PMID: 25238823 DOI: 10.3305/nh.2014.30.3.7531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The most studied roles of serotonin (5-hydroxytryptamine, 5HT) have been related to its action in the Central Nervous System (CNS). However, most of 5HT is produced outside the CNS, mainly in the enterochromaffin cells of the gut. Additionally, other tissues such as the endocrine pancreas, particularly β-cells, have its own serotonin system able to synthesize, secrete and respond to extracellular 5HT through cell surface receptors subtypes that have been grouped in 7 families (HTR1-7). Interestingly, 5HT is stored in granules and released together with insulin from β-cells and its biological significance is likely a combination of intra and extracellular actions. The expression of enzymes involved in 5HT synthesis and their receptors varied markedly in β-pancreatic cells during pregnancy, in parallel with an increase in their insulin secretion potential (probably through the action of Htr3a) and an increase in β-cell mass (through the action of Htr2b and Htr1d). In addition, it has been suggested that gut-derived 5HT may promote hepatic gluconeogenesis during prolonged fasting through Htr2b receptor. Taken together, these findings suggest that peripheral 5HT plays an important role in the regulation of glucose homeostasis through the differential expression and activation of 5-HT membrane receptors on the surface of hepatocytes, adipocytes and pancreatic β-cells.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Departamento de Nutrición, Diabetes y Metabolismo. Pontificia Universidad Católica de Chile. Facultad de Medicina, Universidad de los Andes, Chile. Bioquímico, MSc. Estudiante de Doctorado. Universidad de los Andes..
| | - Víctor Antonio Cortés
- Departamento de Nutrición, Diabetes y Metabolismo. Pontificia Universidad Católica de Chile..
| | - José Eduardo Galgani
- Departamento de Nutrición, Diabetes y Metabolismo. Pontificia Universidad Católica de Chile. UDA-Ciencias de la Salud, Carrera de Nutrición y Dietética. Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile. Nutricionista, PhD..
| | - Pablo Roberto Olmos
- Departamento de Nutrición, Diabetes y Metabolismo. Pontificia Universidad Católica de Chile..
| | - José Luis Santos
- Departamento de Nutrición, Diabetes y Metabolismo. Pontificia Universidad Católica de Chile. Biólogo, PhD MSc. Chile..
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Vega JA, Suazo J, Smalley SV, Cataldo LR, Cubillos G, Santos JL. Subspecies identification of Chimpanzees Pan troglodytes (Primates: Hominidae) from the National Zoo of the Metropolitan Park of Santiago, Chile, using mitochondrial DNA sequences. J Threat Taxa 2014. [DOI: 10.11609/jott.o3611.5712-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Cataldo LR, Olmos P, Valerie Smalley S, Díez A, Parada A, Gejman R, Fadic R, Santos JL. [Mitochondrial DNA heteroplasmy of the m.3243A>G mutation in maternally inherited diabetes and deafness]. Rev Med Chil 2013; 141:305-12. [PMID: 23900320 DOI: 10.4067/s0034-98872013000300004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 11/08/2012] [Indexed: 11/17/2022]
Abstract
Maternally Inherited Diabetes and Deafness (MIDD) is caused by mutations in mitochondrial DNA (mtDNA), mainly m.3243A>G. Severity, onset and clinical phenotype of MIDD patients are partially determined by the proportion of mutant mitochondrial DNA copies in each cell and tissue (heteroplasmy). The identification of MIDD allows a corred treatment with insulin avoiding drugs that may interfere with mitochondrial electrón chain transpon. We estimated the degree of heteroplasmy of the mutation m.3243A>G from blood, saliva, hair root and a muscle biopsy using quantitative PCR (qPCR) in a femóle adult patient. For this purpose, PCR producís were inserted in a vector creating plasmids with 3243A or G. Mutant and wild-type vectors were mixed in different proportions to créate a calibration curve used to interpólate heteroplasmy percentages with qPCR threshold cycles. The proportions of m.3243A>G heteroplasmy were 62% (muscle), 14% (saliva), 6% (blood leukocytes) and 3% in hair root. Quantitative analysis of heteroplasmy showed marked variations in different tissues (highest in muscle and lowest in blood). Given the relatively high heteroplasmy found in saliva, this type of biológical sample may represent an adequate non-invasive way for assessing the presence of m.3243A>G mutations in epidemiologic studies.
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Affiliation(s)
- Luis Rodrigo Cataldo
- Departamento de Nutrición, Diabetes y Metabolismo, Pontificia Universidad Católica de Chile, Chile
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Dussaillant C, Serrano V, Maiz A, Eyheramendy S, Cataldo LR, Chavez M, Smalley SV, Fuentes M, Rigotti A, Rubio L, Lagos CF, Martinez JA, Santos JL. APOA5 Q97X mutation identified through homozygosity mapping causes severe hypertriglyceridemia in a Chilean consanguineous family. BMC Med Genet 2012; 13:106. [PMID: 23151256 PMCID: PMC3523038 DOI: 10.1186/1471-2350-13-106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 10/23/2012] [Indexed: 12/31/2022]
Abstract
Background Severe hypertriglyceridemia (HTG) has been linked to defects in LPL, APOC2, APOA5, LMF1 and GBIHBP1 genes. However, a number of severe HTG cases are probably caused by as yet unidentified mutations. Very high triglyceride plasma levels (>112 mmol/L at diagnosis) were found in two sisters of a Chilean consanguineous family, which is strongly suggestive of a recessive highly penetrant mutation. The aim of this study was to determine the genetic locus responsible for the severe HTG in this family. Methods We carried out a genome-wide linkage study with nearly 300,000 biallelic markers (Illumina Human CytoSNP-12 panel). Using the homozygosity mapping strategy, we searched for chromosome regions with excess of homozygous genotypes in the affected cases compared to non-affected relatives. Results A large homozygous segment was found in the long arm of chromosome 11, with more than 2,500 consecutive homozygous SNP shared by the proband with her affected sister, and containing the APOA5/A4/C3/A1 cluster. Direct sequencing of the APOA5 gene revealed a known homozygous nonsense Q97X mutation (p.Gln97Ter) found in both affected sisters but not in non-affected relatives nor in a sample of unrelated controls. Conclusion The Q97X mutation of the APOA5 gene in homozygous status is responsible for the severe hypertriglyceridemia in this family. We have shown that homozygosity mapping correctly pinpointed the genomic region containing the gene responsible for severe hypertriglyceridemia in this consanguineous Chilean family.
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Affiliation(s)
- Catalina Dussaillant
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Alameda, Santiago, Chile
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Santos JL, Saus E, Smalley SV, Cataldo LR, Alberti G, Parada J, Gratacòs M, Estivill X. Copy number polymorphism of the salivary amylase gene: implications in human nutrition research. J Nutrigenet Nutrigenomics 2012; 5:117-31. [PMID: 22965187 DOI: 10.1159/000339951] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The salivary α-amylase is a calcium-binding enzyme that initiates starch digestion in the oral cavity. The α-amylase genes are located in a cluster on the chromosome that includes salivary amylase genes (AMY1), two pancreatic α-amylase genes (AMY2A and AMY2B) and a related pseudogene. The AMY1 genes show extensive copy number variation which is directly proportional to the salivary α-amylase content in saliva. The α-amylase amount in saliva is also influenced by other factors, such as hydration status, psychosocial stress level, and short-term dietary habits. It has been shown that the average copy number of AMY1 gene is higher in populations that evolved under high-starch diets versus low-starch diets, reflecting an intense positive selection imposed by diet on amylase copy number during evolution. In this context, a number of different aspects can be considered in evaluating the possible impact of copy number variation of the AMY1 gene on nutrition research, such as issues related to human diet gene evolution, action on starch digestion, effect on glycemic response after starch consumption, modulation of the action of α-amylases inhibitors, effect on taste perception and satiety, influence on psychosocial stress and relation to oral health.
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Affiliation(s)
- J L Santos
- Department of Nutrition, Diabetes and Metabolism, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
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