28 results on '"Anne-Dominique Lajoix"'
Search Results
2. Peripancreatic Adipose Tissue Remodeling and Inflammation during High Fat Intake of Palm Oils or Lard in Rats
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Charles Coudray, Karen Muyor, Claire Vigor, Youzan Ferdinand Djohan, Laura Jeanson, Anne-Dominique Lajoix, Jonas Laget, Nathalie Gayrard, Camille Oger, Thierry Durand, Christine Feillet-Coudray, Eric Badia, Jean-Paul Cristol, Bernard Jover, Jean-Marie Galano, Biocommunication en Cardio-Métabolique (BC2M), Université de Montpellier (UM), RD-Néphrologie (R&D), Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046] (PhyMedExp), Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Dynamique Musculaire et Métabolisme (DMEM), Université de Montpellier (UM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), REPERE program from the Conseil Regional Occitanie (France) 18022518, MORNET, Dominique, and Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
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0301 basic medicine ,Blood Glucose ,Male ,medicine.medical_specialty ,Antioxidant ,medicine.medical_treatment ,Adipose tissue ,030209 endocrinology & metabolism ,Inflammation ,lcsh:TX341-641 ,medicine.disease_cause ,Diet, High-Fat ,Article ,03 medical and health sciences ,0302 clinical medicine ,Lipid oxidation ,lipid oxidation ,Internal medicine ,medicine ,Glucose homeostasis ,Animals ,Rats, Wistar ,high fat intake ,2. Zero hunger ,[SDV.MHEP.EM] Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,palm oil ,Nutrition and Dietetics ,Chemistry ,Macrophages ,Body Weight ,food and beverages ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,medicine.disease ,Obesity ,Dietary Fats ,Lipids ,Rats ,adipose tissue ,[SDV.AEN] Life Sciences [q-bio]/Food and Nutrition ,030104 developmental biology ,Endocrinology ,Glucose ,inflammation ,medicine.symptom ,Adipocyte hypertrophy ,[SDV.AEN]Life Sciences [q-bio]/Food and Nutrition ,lcsh:Nutrition. Foods and food supply ,Oxidative stress ,Food Science - Abstract
Excessive fat consumption leads to the development of ectopic adipose tissues, affecting the organs they surround. Peripancreatic adipose tissue is implicated in glucose homeostasis regulation and can be impaired in obesity. High palm oil consumption’s effects on health are still debated. We hypothesised that crude and refined palm oil high-fat feeding may have contrasting effects on peripancreatic adipocyte hypertrophy, inflammation and lipid oxidation compound production in obese rats. In Wistar rats, morphological changes, inflammation and isoprostanoid production following oxidative stress were assessed in peripancreatic adipose tissue after 12 weeks of diets enriched in crude or refined palm oil or lard (56% energy from fat in each case) versus a standard chow diet (11% energy from fat). Epididymal white and periaortic brown adipose tissues were also included in the study. A refined palm oil diet disturbed glucose homeostasis and promoted lipid deposition in periaortic locations, as well as adipocyte hypertrophy, macrophage infiltration and isoprostanoid (5-F2c-isoprostane and 7(RS)-ST-Δ8-11-dihomo-isofuran) production in peripancreatic adipose tissue. Crude palm oil induced a lower impact on adipose deposits than its refined form and lard. Our results show that the antioxidant composition of crude palm oil may have a protective effect on ectopic adipose tissues under the condition of excessive fat intake.
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- 2021
3. Solid‐Phase Synthesis of Substrate‐Based Dipeptides and Heterocyclic Pseudo‐dipeptides as Potential NO Synthase Inhibitors
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Jean Martinez, Anne-Dominique Lajoix, Abdallah Hamze, Booma Ramassamy, Jean-François Hernandez, Thibault Tintillier, Claudia Verna, Elodie Mauchauffée, Jérémy Leroy, Karima Mezghenna, Amine Bouzekrini, Youness Touati-Jallabe, Jean-Luc Boucher, Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et de Biochimie Pharmacologiques et Toxicologiques (LCBPT - UMR 8601), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université de Paris - UFR Sciences Fondamentales et Biomédicales [Sciences], Université de Paris (UP), Biocommunication en Cardio-Métabolique (BC2M), and Université de Montpellier (UM)
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Stereochemistry ,[CHIM.THER]Chemical Sciences/Medicinal Chemistry ,01 natural sciences ,Biochemistry ,Cell Line ,Mice ,chemistry.chemical_compound ,Solid-phase synthesis ,Heterocyclic Compounds ,Drug Discovery ,Animals ,Peptide bond ,Moiety ,Carboxylate ,Enzyme Inhibitors ,General Pharmacology, Toxicology and Pharmaceutics ,Heme ,Solid-Phase Synthesis Techniques ,Pharmacology ,biology ,010405 organic chemistry ,Organic Chemistry ,Substrate (chemistry) ,Active site ,Dipeptides ,Rats ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,chemistry ,Thiourea ,biology.protein ,Molecular Medicine ,Cattle ,Nitric Oxide Synthase - Abstract
International audience; More than 160 arginine analogues modified on the C‐terminus via either an amide bond or a heterocyclic moiety (1,2,4‐oxadiazole, 1,3,4‐oxadiazole and 1,2,4‐triazole) were prepared as potential inhibitors of NO synthases (NOS). A methodology involving formation of a thiocitrulline intermediate linked through its side‐chain on a solid support followed by modification of its carboxylate group was developed. Finally, the side‐chain thiourea group was either let unchanged, S‐alkylated (Me, Et) or guanidinylated (Me, Et) to yield respectively after TFA treatment the corresponding thiocitrulline, S‐Me/Et‐isothiocitrulline and N‐Me/Et‐arginine substrate analogues. They all were tested against three recombinant NOS isoforms. Several compounds containing a S‐Et‐ or a S‐Me‐Itc moiety and mainly belonging to both the dipeptide‐like and 1,2,4‐oxadiazole series were shown to inhibit nNOS and iNOS with IC50 in the 1–50 μM range. Spectral studies confirmed that these new compounds interacted at the heme active site. The more active compounds were found to inhibit intra‐cellular iNOS expressed in RAW264.7 and INS‐1 cells with similar efficiency than the reference compounds L‐NIL and SEIT.
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- 2020
4. 5-HT
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Sina, Faton, Jean-Pol, Tassin, Flore, Duranton, Didier, Bagnol, and Anne-Dominique, Lajoix
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Male ,Motivation ,Indoles ,Ventral Tegmental Area ,Arcuate Nucleus of Hypothalamus ,Aminopyridines ,Feeding Behavior ,Motor Activity ,Piperazines ,Rats, Sprague-Dawley ,Amphetamine ,Eating ,Reward ,Receptor, Serotonin, 5-HT2C ,Serotonin 5-HT2 Receptor Antagonists ,Animals ,Central Nervous System Stimulants ,Food Deprivation ,Serotonin 5-HT2 Receptor Agonists - Abstract
Central serotonin systems have long been associated with the control of feeding behavior and the modulation of behavioral effects of psychostimulants. 5-HT
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- 2017
5. Sodium restriction modulates innate immunity and prevents cardiac remodeling in a rat model of metabolic syndrome
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Cyril Reboul, Michel Tournier, Anne Dominique Lajoix, Caroline Desmetz, Laura Jeanson, C. Rugale, Christelle Reynes, Bernard Jover, Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046] (PhyMedExp), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Aide à la Décision pour une Médecine Personnalisé - Laboratoire de Biostatistique, Epidémiologie et Recherche Clinique - EA 2415 (AIDMP), Université Montpellier 1 (UM1)-Université de Montpellier (UM), Biocommunication en Cardio-Métabolique (BC2M), Université de Montpellier (UM), EA4278 Laboratoire de Pharm-Ecologie Cardiovasculaire (LaPEC), Avignon Université (AU), Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Molécules Thérapeutiques in silico (MTI), Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Génomique Fonctionnelle (IGF), and Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
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0301 basic medicine ,medicine.medical_specialty ,Macrophage ,Cardiac fibrosis ,food.diet ,[SDV]Life Sciences [q-bio] ,Cardiomegaly ,Inflammation ,Fructose ,030204 cardiovascular system & hematology ,Low sodium diet ,Biology ,[SDV.IMM.II]Life Sciences [q-bio]/Immunology/Innate immunity ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,food ,[SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system ,Fibrosis ,Internal medicine ,Renin–angiotensin system ,Dietary Carbohydrates ,medicine ,Animals ,Sodium Chloride, Dietary ,Molecular Biology ,ComputingMilieux_MISCELLANEOUS ,Metabolic Syndrome ,Innate immunity ,2. Zero hunger ,Innate immune system ,Diet, Sodium-Restricted ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,medicine.disease ,Angiotensin II ,Immunity, Innate ,Rats ,3. Good health ,Disease Models, Animal ,Cardiac hypertrophy ,030104 developmental biology ,Endocrinology ,Molecular Medicine ,medicine.symptom ,[SDV.AEN]Life Sciences [q-bio]/Food and Nutrition ,Low sodium - Abstract
International audience; In the view of the relationships between excessive sodium intake, immunity and target organ damage, we hypothesized that reduction in dietary sodium would be beneficial in the prevention of cardiac alterations through a restrained local immunity response in a rat model of metabolic syndrome. Sprague-Dawley rats were fed a 60% fructose diet with either a normal sodium (0.64% NaCl) or a low sodium content (b 0.01% NaCl) for 8 weeks. After 4 weeks, rats were infused or not with angiotensin II (200 ng·kg −1 ·min −1 , sc) for 4 weeks. Tail-cuff blood pressure was determined in conscious rats. Heart and left ventricle weight, cardiomyocyte size, and cardiac fibrosis were evaluated. We performed a transcriptomic analysis in order to identify differentially regulated cardiac mRNAs between normal and low sodium diets. We validated those results using qPCR and immunohistochemistry. Angiotensin II-induced blood pressure rise was blunted (~50%) in the low-sodium fed rats while cardiac hyper-trophy and fibrosis were prevented. Transcriptomic analysis revealed 66 differentially regulated genes including 13 downregulated genes under the low sodium diet and implicated in the innate immune response. This was confirmed by reduced cardiac macrophages infiltration under the low sodium diet. Dietary sodium restriction prevents structural alterations of the heart of rats with fructose-induced insulin resistance and angiotensin II-hypertension. The reduction of cardiac inflammation and macrophage infiltration suggests that innate immunity has an important role in the beneficial effect of sodium restriction on cardiac remodeling.
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- 2017
6. Dietary sodium restriction prevents kidney damage in high fructose-fed rats
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C. Rugale, Anne Dominique Lajoix, Carole Oudot, Bernard Jover, Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046] (PhyMedExp), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de pharmacologie et innovation dans le diabète (CPID), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1), Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
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Blood Glucose ,Male ,Time Factors ,Adipose tissue ,030204 cardiovascular system & hematology ,Kidney ,medicine.disease_cause ,[SDV.MHEP.UN]Life Sciences [q-bio]/Human health and pathology/Urology and Nephrology ,Desmin ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,0302 clinical medicine ,ComputingMilieux_MISCELLANEOUS ,2. Zero hunger ,0303 health sciences ,Diet, Sodium-Restricted ,3. Good health ,medicine.anatomical_structure ,Nephrology ,Inflammation Mediators ,medicine.symptom ,medicine.medical_specialty ,Inflammation ,Fructose ,Intra-Abdominal Fat ,03 medical and health sciences ,Insulin resistance ,Internal medicine ,medicine ,Albuminuria ,Animals ,030304 developmental biology ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,business.industry ,Macrophages ,NADPH Oxidases ,Kidney metabolism ,medicine.disease ,Fibrosis ,Rats ,Disease Models, Animal ,Oxidative Stress ,Endocrinology ,chemistry ,Insulin Resistance ,business ,[SDV.AEN]Life Sciences [q-bio]/Food and Nutrition ,Oxidative stress - Abstract
Sodium depletion has a protective effect on target-organ damage in hypertension independent of blood pressure. Here we tested whether chronic dietary sodium restriction may prevent the development of renal alterations associated with insulin resistance by reducing the inflammatory and oxidant state. Rats were fed normal-salt-60% fructose, low-salt-60% fructose, or control normal-salt diet for 12 weeks. Insulin resistance induced by high-fructose diet was associated with an increase in albuminuria, tubular and glomerular hypertrophy, and inflammation of kidney and adipose tissue. The low-salt diet improved insulin sensitivity and prevented kidney damage. These beneficial effects of sodium depletion were associated with a decrease in renal inflammation (macrophage infiltration, IL-6, TNF-α) and oxidative stress (NADPH oxidase activity), and a prevention of histologic changes in retroperitoneal fat induced by high fructose. Thus, dietary salt depletion has beneficial effects on renal and metabolic alterations associated with a high-fructose diet in rats.
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- 2013
7. Expression of purinergic P2Y receptor subtypes by INS-1 insulinoma β-cells: A molecular and binding characterization
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René Gross, Jacques Vignon, Pierre Petit, Laura Lugo-Garcia, Romain Filhol, Anne-Dominique Lajoix, Centre de pharmacologie et innovation dans le diabète (CPID), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
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Agonist ,P2Y receptor ,medicine.medical_specialty ,medicine.drug_class ,Plasma protein binding ,Biology ,03 medical and health sciences ,0302 clinical medicine ,Western blot ,Cell Line, Tumor ,Insulin-Secreting Cells ,Internal medicine ,medicine ,Animals ,RNA, Messenger ,Binding site ,Receptor ,030304 developmental biology ,Pharmacology ,0303 health sciences ,medicine.diagnostic_test ,Receptors, Purinergic P2 ,Ligand binding assay ,Purinergic receptor ,Thionucleotides ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,Molecular biology ,Rats ,Adenosine Diphosphate ,Endocrinology ,Insulinoma ,030217 neurology & neurosurgery ,Protein Binding - Abstract
National audience; Purinergic P2Y-receptor agonists amplify glucose-induced insulin secretion from pancreatic beta-cells, thus offering new opportunities for the treatment of type 2 diabetes. However, little is known about which subtypes of purinergic P2Y receptors are expressed in these cells. The INS-1 beta-cell line is used as a model of pancreatic beta-cells, expressing most of their properties. Therefore, we investigated the expression of different molecular subtypes in this cell line by means of real time Polymerase Chain Reaction and Western blot. We also performed a characterization of the binding of a prototypic purinergic P2Y agonist, Adenosine-5'-O-(1-[(35)S]thiotriphosphate) (ATP-alpha-[(35)S]), to cell membrane homogenates. The molecular analysis evidenced the presence of five different purinergic P2Y receptor subtypes (P2Y(1), P2Y(2), P2Y(4), P2Y(6) and P2Y(12)), which were expressed at similar levels. The Western blot analysis allowed detecting corresponding proteins. The binding assay demonstrated a specific ATP-alpha-[(35)S] interaction on high (40%) and low (60%) affinity components. The analysis of ATP-alpha-[(35)S] pharmacological profile on both sites permitted to classify the high affinity binding site as representative of the purinergic P2Y(1) receptor subtype and the low affinity binding site of the P2Y(4) and/or P2Y(6) receptor subtypes. ATP-alpha-S and Adenosine-5'-O-(2-thiodiphosphate) (ADP-beta-S) exhibited opposite selectivity on high and low affinity binding sites.Although purinergic P2Y(1) receptor, or a P2Y(1)-like subtype, has been generally considered as that implicated in the modulation of glucose-induced insulin release, the present data show that the beta-cell expresses a complex profile of purinergic P2Y receptor subtypes, the functional implication of which remains to be fully elucidated.
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- 2007
8. Protein Inhibitor of Neuronal Nitric Oxide Synthase (PIN) Is a New Regulator of Glucose-Induced Insulin Secretion
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Stéphanie Badiou, Samuel Dietz, René Gross, Sylvie Peraldi-Roux, Thierry Chardès, Pierre Petit, Florence Tribillac, Anne-Dominique Lajoix, Cindy Aknin, Centre de pharmacologie et innovation dans le diabète (CPID), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1), Département de biochimie [Montpellier], Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Hôpital Lapeyronie, Institut du Cancer de Montpellier (ICM), Institut de Génomique Fonctionnelle (IGF), Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Plate-forme transcriptome, Génopole Montpellier, Institut Universitaire de Recherche Clinique, Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Petit, Pierre
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Cytoplasmic Dyneins ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,MESH: Nitric Oxide Synthase Type I ,Nitric Oxide Synthase Type I ,MESH: Myosin Heavy Chains ,chemistry.chemical_compound ,0302 clinical medicine ,Insulin Secretion ,Myosin ,Homeostasis ,Insulin ,MESH: Animals ,[SDV.MHEP.EM] Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,0303 health sciences ,biology ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,MESH: Glucose ,Nitric oxide synthase ,medicine.anatomical_structure ,MESH: Homeostasis ,[SDV.BBM.GTP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN] ,Sodium nitroprusside ,medicine.drug ,medicine.medical_specialty ,MESH: Rats ,Myosin Type V ,MESH: Insulin ,MESH: Myosin Type V ,Cell Line ,Nitric oxide ,Islets of Langerhans ,03 medical and health sciences ,[SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN] ,Internal medicine ,Internal Medicine ,medicine ,Animals ,Secretion ,Rats, Wistar ,030304 developmental biology ,Myosin Heavy Chains ,MESH: Islets of Langerhans ,Pancreatic islets ,Dyneins ,Colocalization ,MESH: Rats, Wistar ,MESH: Dynein ATPase ,MESH: Cell Line ,Rats ,Glucose ,Endocrinology ,chemistry ,biology.protein ,030217 neurology & neurosurgery - Abstract
We previously showed that pancreatic β-cells express neuronal nitric oxide synthase (nNOS) that controls insulin secretion through two catalytic activities: nitric oxide (NO) production and cytochrome c reductase activity. We now provide evidence that the endogenous protein inhibitor of nNOS (PIN) is expressed in rat pancreatic islets and INS-1 cells. Double-immunofluorescence studies showed a colocalization of PIN with both nNOS and myosin Va in insulin-secreting β-cells. Electron microscopy studies confirmed that PIN is mainly associated with insulin secretory granules and colocated with nNOS in the latter. In addition, PIN overexpression in INS-1 cells enhanced glucose-induced insulin secretion, which is only partly reversed by addition of an NO donor, sodium nitroprusside (SNP), and unaffected by the inhibitor of cytochrome c reductase activity, miconazole. In contrast, the pharmacological inhibitor of nNOS, Nω-nitro-l-arginine methyl ester, amplified glucose-induced insulin secretion, an effect insensitive to SNP but completely normalized by the addition of miconazole. Thus, PIN insulinotropic effect could be related to its colocalization with the actin-based molecular motor myosin Va and as such be implicated in the physiological regulation of glucose-induced insulin secretion at the level of the exocytotic machinery.
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- 2006
9. P2Y receptor activation enhances insulin release from pancreatic β-cells by triggering the cyclic AMP/protein kinase A pathway
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Pierre Petit, Christophe Broca, Roig A, Chevassus H, M. Manteghetti, Anne-Dominique Lajoix, and Belloc C
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Male ,Purinergic P2 Receptor Agonists ,medicine.medical_specialty ,Islets of Langerhans ,Insulin receptor substrate ,Internal medicine ,Tumor Cells, Cultured ,medicine ,Animals ,Insulin ,Rats, Wistar ,Protein kinase A signaling ,Protein kinase A ,Protein kinase B ,Glucagon-like peptide 1 receptor ,Pharmacology ,Dose-Response Relationship, Drug ,biology ,Receptors, Purinergic P2 ,Chemistry ,Pancreatic islets ,General Medicine ,Thionucleotides ,Cyclic AMP-Dependent Protein Kinases ,IRS2 ,Rats ,Adenosine Diphosphate ,Insulin receptor ,Endocrinology ,medicine.anatomical_structure ,biology.protein - Abstract
Adenine nucleotides stimulate insulin secretion by binding to P2 receptors of the pancreatic beta-cells; the stimulus-secretion coupling is not yet clearly established and may depend on the receptor subtype. The aim of the present study was to further investigate the mechanism whereby P2Y receptor agonists enhance glucose-induced insulin secretion. Experiments were performed in rat pancreatic islets and in the INS-1 secreting cell line in the presence of a slightly stimulating glucose concentration (8.3 mmol/l). In isolated islets, the P2Y receptor agonist ADPbetaS (50 micromol/l) induced a significant fivefold increase in the cyclic AMP (cAMP) content, from 43.4+/-3.7 fmol/10 islets in controls to 210.6+/-12.0; it still induced a 4.5-fold increase in cAMP content in the absence of calcium. In another series of experiments, ADPbetaS (50 micromol/l) significantly increased glucose-induced insulin secretion from 7.7+/-0.6 ng/3 islets in controls to 11.2+/-1.0. The adenylyl cyclase inhibitor SQ 22,536 (9-[tetrahydro-2-furanyl]-9 H-purin-6-amine; 100 micromol/l), which was ineffective alone, completely prevented the stimulating effect of ADPbetaS. In a set of experiments in which ADPbetaS increased glucose-induced insulin secretion from 10.0+/-0.7 ng/3 islets to 12.6+/-0.8, the inhibitor of cAMP-dependent protein kinase, TPCK (tos-phe-chloromethylketone; 3 micromol/l), which was ineffective alone, also prevented the stimulating effect of ADPbetaS. In incubated INS-1 cells, the P2Y receptor ligand ATPalphaS increased significantly both the content of cAMP and the release of insulin, in a concentration-dependent manner in the range of 50-150 micromol/l; the insulin release was significantly correlated with the cAMP content. In conclusion, the present results show that P2Y receptor agonists, ADPbetaS and ATPalphaS, amplify glucose-induced insulin secretion by activating beta-cell adenylyl cyclase and the subsequent cAMP/protein kinase A signaling pathway.
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- 2002
10. Chemical Analysis and Antihyperglycemic Activity of an Original Extract from Burdock Root (Arctium lappa)
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Anne-Dominique Lajoix, Michel Tournier, Marie Faucanie, Hugues Chevassus, Jérémy Leroy, Luc P. R. Bidel, Guillaume Cazals, Jacqueline Azay-Milhau, Karine Ferrare, Didier Tousch, Démarche intégrée pour l'obtention d'aliments de qualité (UMR Qualisud), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Biocommunication en Cardio-Métabolique (BC2M), Université de Montpellier (UM), Amélioration génétique et adaptation des plantes méditerranéennes et tropicales (UMR AGAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Centre de pharmacologie et innovation dans le diabète (CPID), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Université de La Réunion (UR)-Université de Montpellier (UM)-Avignon Université (AU)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
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Male ,Burdock root arctium lappa ,Glucose uptake ,[SDV]Life Sciences [q-bio] ,Quinic Acid ,Carbohydrate metabolism ,Plant Roots ,Cell Line ,Arctium lappa L. (Asteraceae) ,In vivo ,in vitro investigations ,Insulin Secretion ,Animals ,Hypoglycemic Agents ,Insulin ,Rats, Wistar ,Insulin secretion ,Muscle Cells ,Plant Extracts ,Chemistry ,dried burdock root extract ,antihyperglycemic effects ,in vivo effects ,General Chemistry ,Glucagon ,In vitro ,Arctium ,Rats ,Caffeoylquinic acid ,Glucose ,Biochemistry ,Cell culture ,chemical analysis ,Glucose-6-Phosphatase ,Hepatocytes ,General Agricultural and Biological Sciences - Abstract
In the present study, we obtained a dried burdock root extract (DBRE) rich in caffeoylquinic acids derivatives. We performed the chemical characterization of DBRE and explored its antihyperglycemic potential in both in vitro and in vivo experiments. Chemical analysis of DBRE using LC-MS and GC-MS revealed the presence of a great majority of dicaffeoylquinic acid derivatives (75.4%) of which 1,5-di-O-caffeoyl-4-O-maloylquinic acid represents 4496 of the extract. In the in vitro experiments, DBRE is able to increase glucose uptake in cultured L6 myocytes and to decrease glucagon-induced glucose output from rat isolated hepatocytes together with a reduction of hepatic glucose 6-phosphatase activity. DBRE did not increase insulin secretion in the INS-1 pancreatic beta-cell line. In vivo, DBRE improves glucose tolerance both after intraperitoneal and oral subchronic administration. In conclusion, our data demonstrate that DBRE constitutes an original set of caffeoylquinic acid derivatives displaying antihyperglycemic properties.
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- 2014
11. A Neuronal Isoform of Nitric Oxide Synthase Expressed in Pancreatic β-Cells Controls Insulin Secretion
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René Gross, Thierry Chardès, Samuel Dietz, M. Manteghetti, Anne-Dominique Lajoix, Christophe Broca, Claes B. Wollheim, Sylvie Peraldi-Roux, M. Roye, Florence Tribillac, Gérard Ribes, Hubbert Reggio, Biologie Intégrative et Virologie des Insectes [Univ. de Montpellier II] (BIVI), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA)
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Male ,Miconazole ,Arginine ,[SDV]Life Sciences [q-bio] ,Endocrinology, Diabetes and Metabolism ,Nitric Oxide Synthase Type I ,Mitochondrion ,Subcellular Fractions/enzymology ,Cell Membrane/drug effects/physiology ,chemistry.chemical_compound ,Insulin Secretion ,Insulin ,Tissue Distribution ,Clotrimazole ,ddc:616 ,Cytochrome c ,Drug Synergism ,Nitroprusside/pharmacology ,NOS ,Electrophysiology ,Nitric oxide synthase ,medicine.anatomical_structure ,Sodium nitroprusside ,CONTROLE ,Subcellular Fractions ,medicine.drug ,Nitroprusside ,Gene isoform ,medicine.medical_specialty ,Nitric Oxide Synthase/antagonists & inhibitors/genetics/metabolism ,Molecular Sequence Data ,Clotrimazole/pharmacology ,Biology ,Nitric oxide ,Islets of Langerhans ,Glucose/administration & dosage/pharmacology ,Internal medicine ,Internal Medicine ,medicine ,Animals ,Succinates/pharmacology ,Rats, Wistar ,Insulin/secretion ,Base Sequence ,Dose-Response Relationship, Drug ,Pancreatic islets ,Islets of Langerhans/drug effects/metabolism/physiology ,Cell Membrane ,Succinates ,Base Sequence/genetics ,Miconazole/pharmacology ,Rats ,Glucose ,Endocrinology ,nervous system ,chemistry ,biology.protein ,Nitric Oxide Synthase ,Arginine/pharmacology - Abstract
Evidence is presented showing that a neuronal isoform of nitric oxide synthase (NOS) is expressed in rat pancreatic islets and INS-1 cells. Sequencing of the coding region indicated a 99.8% homology with rat neuronal NOS (nNOS) with four mutations, three of them resulting in modifications of the amino acid sequence. Double-immunofluorescence studies demonstrated the presence of nNOS in insulin-secreting beta-cells. Electron microscopy studies showed that nNOS was mainly localized in insulin secretory granules and to a lesser extent in the mitochondria and the nucleus. We also studied the mechanism involved in the dysfunction of the beta-cell response to arginine and glucose after nNOS blockade with N(G)-nitro-L-arginine methyl ester. Our data show that miconazole, an inhibitor of nNOS cytochrome c reductase activity, either alone for the experiments with arginine or combined with sodium nitroprusside for glucose, is able to restore normal secretory patterns in response to the two secretagogues. Furthermore, these results were corroborated by the demonstration of a direct enzyme-substrate interaction between nNOS and cytochrome c, which is strongly reinforced in the presence of the NOS inhibitor. Thus, we provide immunochemical and pharmacological evidence that beta-cell nNOS exerts, like brain nNOS, two catalytic activities: a nitric oxide production and an NOS nonoxidating reductase activity, both of which are essential for normal beta-cell function. In conclusion, we suggest that an imbalance between these activities might be implicated in beta-cell dysregulation involved in certain pathological hyperinsulinic states.
- Published
- 2001
12. Antihyperglycemic effect of a natural chicoric acid extract of chicory (Cichorium intybus L.): a comparative in vitro study with the effects of caffeic and ferulic acids
- Author
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Karine Ferrare, Jérémy Leroy, Michel Tournier, Didier Tousch, Anne-Dominique Lajoix, Jordan Aubaterre, Jacqueline Azay-Milhau, Centre de pharmacologie et innovation dans le diabète (CPID), Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS), Biocommunication en Cardio-Métabolique (BC2M), Université de Montpellier (UM), and Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1)
- Subjects
Male ,Glycogenolysis ,Glucose uptake ,medicine.medical_treatment ,[SDV]Life Sciences [q-bio] ,Hydroxycinnamic acids ,Pharmacology ,Chicory ,Ferulic acid ,chemistry.chemical_compound ,0302 clinical medicine ,Drug Discovery ,Caffeic acid ,Chicoric acid extract ,Glucose 6-phosphatase ,Insulin ,Cells, Cultured ,0303 health sciences ,Glucose tolerance test ,medicine.diagnostic_test ,biology ,Muscles ,food and beverages ,3. Good health ,Biochemistry ,030220 oncology & carcinogenesis ,Glucose-6-Phosphatase ,Microsomes, Liver ,Glycogen ,Coumaric Acids ,Cell Line ,Antihyperglycemic effect ,03 medical and health sciences ,Caffeic Acids ,Chlorogenic acid ,Cell Line, Tumor ,medicine ,In vitro experiments ,Animals ,Hypoglycemic Agents ,Rats, Wistar ,030304 developmental biology ,Plant Extracts ,Succinates ,Rats ,Glucose ,chemistry ,biology.protein ,Hepatocytes - Abstract
Ethnopharmacological relevance In Eurasia folk medicine, roots of chicory ( Cichorium intybus L.) have been reported to exert antidiabetic benefits. In vitro , a natural chicoric acid extract (NCRAE) from Cichorium intybus root has been shown to increase insulin secretion by pancreatic β-cells and glucose uptake by muscle cells. Materials and methods In vitro experiments were designed to compare the effects of two hydroxycinnamic acids, caffeic and ferulic acids, to those obtained with NCRAE (50 and 100 µg.mL −1 ) on the three major tissues implicated in glycemic regulation (pancreas, muscle and liver). In vivo experiments were performed in Wistar rats submitted to a daily intraperitoneal injection of NCRAE (3, 15 or 30 mg kg −1 ) for 4 days. On the fourth day, an intraperitoneal glucose tolerance test (IPGTT; 1 g kg −1 ) was carried out. Results Our results show that the three compounds we used are able each to induce an original response. Caffeic acid mainly promotes a decrease in hepatic glycogenolysis. Ferulic acid elicits a clear increase of insulin release and a reduction of hepatic glycogenolysis. However, this compound induces an inhibition of muscle glucose uptake. NCRAE provokes an increase of insulin release and glucose uptake without any effect on hepatic glycogenolysis. We could also show that none of these compounds implicates hepatic glucose 6-phosphatase in contrast to chlorogenic acid, known as an inhibitor of glucose 6-phosphatase and which is able to decrease glucose output from hepatocytes. Our results point out that NCRAE is able to decrease blood glucose without any effect hepatic effect. Our in vivo experiments bring evidence that 4 daily IP administrations of NCRAE improve IP glucose tolerance in a dose-dependent manner and mainly via an insulin sensitizing effect. Conclusions We conclude that NCRAE presents an antihyperglycemic effect essentially due to a peripheral effect on muscle glucose uptake.
- Published
- 2013
13. Counteracting neuronal nitric oxide synthase proteasomal degradation improves glucose transport in insulin-resistant skeletal muscle from Zucker fa/fa rats
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René Gross, Viviana Delgado-Betancourt, K. Mezghenna, F. Castex, Jérémy Leroy, Sylvain Gervais, Jacqueline Azay-Milhau, Didier Tousch, Anne-Dominique Lajoix, Biocommunication en Cardio-Métabolique (BC2M), Université de Montpellier (UM), Laboratoire de Mathématiques Jean Leray (LMJL), Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN), Institut de Génomique Fonctionnelle - Montpellier GenomiX (IGF MGX), Institut de Génomique Fonctionnelle (IGF), and Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Gene isoform ,Male ,medicine.medical_specialty ,Proteasome Endopeptidase Complex ,[SDV]Life Sciences [q-bio] ,Endocrinology, Diabetes and Metabolism ,Blotting, Western ,Type 2 diabetes ,Nitric Oxide Synthase Type I ,Biology ,Insulin resistance ,Internal medicine ,Internal Medicine ,medicine ,Myocyte ,Animals ,Immunoprecipitation ,Muscle, Skeletal ,Cells, Cultured ,Muscle Cells ,Glucose Transporter Type 4 ,Reverse Transcriptase Polymerase Chain Reaction ,Glucose transporter ,Skeletal muscle ,medicine.disease ,Rats ,Rats, Zucker ,Insulin receptor ,medicine.anatomical_structure ,Endocrinology ,Glucose ,biology.protein ,Insulin Resistance ,GLUT4 - Abstract
Insulin-mediated glucose transport and utilisation are decreased in skeletal muscle from type 2 diabetic and glucose-intolerant individuals because of alterations in insulin receptor signalling, GLUT4 translocation to the plasma membrane and microvascular blood flow. Catalytic activity of the muscle-specific isoform of neuronal nitric oxide synthase (nNOS) also participates in the regulation of glucose transport and appears to be decreased in a relevant animal model of drastic insulin resistance, the obese Zucker fa/fa rat. Our objective was to determine the molecular mechanisms involved in this defect.Isolated rat muscles and primary cultures of myocytes were used for western blot analysis of protein expression, immunohistochemistry, glucose uptake measurements and GLUT4 translocation assays.nNOS expression was reduced in skeletal muscle from fa/fa rats. This was caused by increased ubiquitination of the enzyme and subsequent degradation by the ubiquitin proteasome pathway. The degradation occurred through a greater interaction of nNOS with the chaperone heat-shock protein 70 and the co-chaperone, carboxyl terminus of Hsc70-interacting protein (CHIP). In addition, an alteration in nNOS sarcolemmal localisation was observed. We confirmed the implication of nNOS breakdown in defective insulin-induced glucose transport by demonstrating that blockade of proteasomal degradation or overexpression of nNOS improved basal and/or insulin-stimulated glucose uptake and GLUT4 translocation in primary cultures of insulin-resistant myocytes.Recovery of nNOS in insulin-resistant muscles should be considered a potential new approach to address insulin resistance.
- Published
- 2013
14. M19 modulates skeletal muscle differentiation and insulin secretion in pancreatic β-cells through modulation of respiratory chain activity
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K. Mezghenna, Linda Cambier, Béatrice Chabi, René Gross, Patrice Rassam, Charles Auffray, Eric Eveno, Anne-Dominique Lajoix, Chantal Wrutniak-Cabello, Pascal Pomiès, Centre de pharmacologie et innovation dans le diabète (CPID), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Anatomy and Physiology ,muscle ,Organogenesis ,Respiratory chain ,lcsh:Medicine ,MESH: Monitoring, Physiologic ,Mitochondrion ,Biochemistry ,Mice ,Adenosine Triphosphate ,Insulin-Secreting Cells ,maladie génétique ,Insulin Secretion ,Molecular Cell Biology ,Myocyte ,Insulin ,lcsh:Science ,Musculoskeletal System ,Mitochondrial nucleoid ,0303 health sciences ,Multidisciplinary ,030302 biochemistry & molecular biology ,adn ,Cell Differentiation ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,myogénèse ,Cell biology ,Mitochondria ,acide aminé ,MESH: Evoked Potentials ,Protein Transport ,medicine.anatomical_structure ,mitochondrie ,protéine ,myopathies métaboliques ,Medicine ,diabète ,Research Article ,Mitochondrial DNA ,Molecular Sequence Data ,Endocrine System ,Biology ,Protein Sorting Signals ,MESH: Nervous System Diseases ,Electron Transport ,Mitochondrial Proteins ,03 medical and health sciences ,Oxygen Consumption ,cellules bêta pancréatiques ,medicine ,cancer ,Nucleoid ,Animals ,Humans ,Amino Acid Sequence ,Muscle, Skeletal ,insuline ,MESH: Coma ,030304 developmental biology ,Muscle Cells ,MESH: Humans ,lcsh:R ,Skeletal muscle ,MESH: Multiple Sclerosis ,maladie respiratoire ,Metabolic Disorders ,DNAJA3 ,lcsh:Q ,MESH: Alzheimer Disease ,[SDV.MHEP]Life Sciences [q-bio]/Human health and pathology ,Biomarkers ,HeLa Cells - Abstract
International audience; Mitochondrial dysfunction due to nuclear or mitochondrial DNA alterations contributes to multiple diseases such as metabolic myopathies, neurodegenerative disorders, diabetes and cancer. Nevertheless, to date, only half of the estimated 1,500 mitochondrial proteins has been identified, and the function of most of these proteins remains to be determined. Here, we characterize the function of M19, a novel mitochondrial nucleoid protein, in muscle and pancreatic β-cells. We have identified a 13-long amino acid sequence located at the N-terminus of M19 that targets the protein to mitochondria. Furthermore, using RNA interference and over-expression strategies, we demonstrate that M19 modulates mitochondrial oxygen consumption and ATP production, and could therefore regulate the respiratory chain activity. In an effort to determine whether M19 could play a role in the regulation of various cell activities, we show that this nucleoid protein, probably through its modulation of mitochondrial ATP production, acts on late muscle differentiation in myogenic C2C12 cells, and plays a permissive role on insulin secretion under basal glucose conditions in INS-1 pancreatic β-cells. Our results are therefore establishing a functional link between a mitochondrial nucleoid protein and the modulation of respiratory chain activities leading to the regulation of major cellular processes such as myogenesis and insulin secretion.
- Published
- 2011
15. Increased neuronal nitric oxide synthase dimerisation is involved in rat and human pancreatic beta cell hyperactivity in obesity
- Author
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B Nadal, F. Castex, Pascal Pomiès, K. Mezghenna, Pierre Petit, René Gross, J. Leroy, Linda Cambier, Nadja Niclauss, Anne-Dominique Lajoix, Ramon Gomis, C Cazevieille, Thierry Berney, and A Chalançon
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Male ,medicine.medical_specialty ,Insulin-Secreting Cells/drug effects/metabolism/secretion/ultrastructure ,Endocrinology, Diabetes and Metabolism ,RNA, Messenger/metabolism ,Type 2 diabetes ,Nitric Oxide Synthase Type I ,Gene Expression Regulation, Enzymologic ,Rats, Mutant Strains ,Tissue Culture Techniques ,Islets of Langerhans ,Insulin resistance ,Internal medicine ,Insulin-Secreting Cells ,Obesity/metabolism ,Insulin Secretion ,Internal Medicine ,medicine ,Animals ,Humans ,Insulin ,Obesity ,RNA, Messenger ,Cells, Cultured ,Regulation of gene expression ,ddc:617 ,business.industry ,Pancreatic islets ,Nitric Oxide Synthase Type I/antagonists & inhibitors/genetics/metabolism ,Middle Aged ,medicine.disease ,Transport protein ,Mitochondria ,Rats ,Rats, Zucker ,Protein Transport ,Endocrinology ,medicine.anatomical_structure ,Insulin/metabolism/secretion ,Islets of Langerhans/drug effects/metabolism/secretion/ultrastructure ,Female ,Beta cell ,Insulin Resistance ,Mitochondria/drug effects/metabolism/ultrastructure ,business ,Dimerization ,Function (biology) - Abstract
Pancreatic beta cell hyperactivity is known to occur in obesity, particularly in insulin-resistant states. Our aim was to investigate whether changes in neuronal nitric oxide synthase (nNOS) function affect beta cell compensation in two relevant models: the Zucker fa/fa rats and pancreatic islets from obese humans.Glucose-induced insulin response was evaluated in the isolated perfused rat pancreas and in human pancreatic islets from obese individuals. Expression of nNOS (also known as NOS1) and subcellular localisation of nNOS were studied by quantitative RT-PCR, immunoblotting, immunofluorescence and electron microscopy.Pancreatic beta cells from Zucker fa/fa rats and obese individuals were found to be hyper-responsive to glucose. Pharmacological blockade of nNOS was unable to modify beta cell response to glucose in fa/fa rats and in islets from obese individuals, suggesting an abnormal control of insulin secretion by the enzyme. In both cases, nNOS activity in islet cell extracts remained unchanged, despite a drastic increase in nNOS protein and an enhancement in the dimer/monomer ratio, pointing to the presence of high amounts of catalytically inactive enzyme. This relative decrease in activity could be mainly related to increases in islet asymmetric dimethyl-arginine content, an endogenous inhibitor of nNOS activity. In addition, mitochondrial nNOS level was decreased, which contrasts with a strongly increased association with insulin granules.Increased nNOS production and dimerisation, together with a relative decrease in catalytic activity and relocalisation, are involved in beta cell hyperactivity in insulin-resistant rats but also in human islets isolated from obese individuals.
- Published
- 2011
16. Is static magnetic field exposure a new model of metabolic alteration? Comparison with Zucker rats
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Jacques Mercier, René Gross, Hafedh Abdelmelek, Karen Lambert, Hatem Belguith, Anne-Dominique Lajoix, Miryam Elferchichi, Annick Bourret, and Mohsen Sakly
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Male ,medicine.medical_specialty ,medicine.medical_treatment ,Carbohydrate metabolism ,Hypoinsulinemia ,Diabetes Mellitus, Experimental ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Electromagnetic Fields ,Species Specificity ,Diabetes mellitus ,Internal medicine ,medicine ,Animals ,Radiology, Nuclear Medicine and imaging ,Rats, Wistar ,030304 developmental biology ,0303 health sciences ,Glucose tolerance test ,Radiological and Ultrasound Technology ,Glycogen ,medicine.diagnostic_test ,Chemistry ,Cholesterol ,Insulin ,Muscles ,Temperature ,Carbohydrate ,Glucose Tolerance Test ,medicine.disease ,Lipid Metabolism ,Rats ,Rats, Zucker ,Oxygen ,Endocrinology ,Glucose ,Liver ,030217 neurology & neurosurgery - Abstract
Purpose: The aim of this study was to investigate if the metabolic alterations observed after static magnetic field (SMF) exposure participates in the development of a pre-diabetic state. A comparison study using the insulin resistant animal model, the Zucker rat and the SMF-exposed Wistar rat was carried out. Materials and methods: Zucker rats were compared to Wistar rats either exposed to a 128 mT or 0 mT SMF (sham exposed) and analysed. This moderate-intensity SMF exposure of Wistar rats was performed for 1 h/day during 15 consecutive days. Results: Wistar rats exposed to the SMF showed increased levels of carbohydrate and lipid metabolites (i.e., lactate, glycerol, cholesterol and phospholipids) compared to sham-exposed rats. Zucker rats displayed a normoglycemia associated with a high insulin level as opposed to Wistar rats which presented hyperglycemia and hypoinsulinemia after exposure to the SMF. During the glucose tolerance test, unexposed Zucker rats and Wistar rats exposed to the SMF exhibited a significantly higher hyperglycemia compared to sham-exposed Wistar rats suggesting an impairment of glucose clearance. In muscle, glycogen content was lower and phospholipids content was elevated for both unexposed Zucker rats and Wistar rats exposed to the SMF compared to Wistar rats sham control. Conclusions: This study provides evidence that the metabolic alterations following exposure to a static magnetic field of moderate intensity could trigger the development of a pre-diabetic state.
- Published
- 2011
17. Effects of exposure to a 128-mT static magnetic field on glucose and lipid metabolism in serum and skeletal muscle of rats
- Author
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René Gross, Karen Lambert, Lore Metz, Marjorie Coisy-Quivy, Hatem Belguith, Mohsen Sakly, Jacques Mercier, Miryam Elferchichi, Hafedh Abdelmelek, Anne-Dominique Lajoix, Laboratoire de Physiologie Intégrée, Faculté des Sciences de Bizerte [Université de Carthage], Université de Carthage - University of Carthage-Université de Carthage - University of Carthage, Muscle et pathologies, Université Montpellier 1 (UM1)-IFR3, Université Montpellier 1 (UM1)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM), Physiologie & médecine expérimentale du Cœur et des Muscles [U 1046] (PhyMedExp), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Centre de pharmacologie et innovation dans le diabète (CPID), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1), Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS), and Passerieux, Emilie
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,Skeletal muscle ,Environmental pollution ,Biology ,Static magnetic fields ,03 medical and health sciences ,chemistry.chemical_compound ,Magnetics ,0302 clinical medicine ,Internal medicine ,medicine ,[SDV.EE.SANT] Life Sciences [q-bio]/Ecology, environment/Health ,Animals ,Glycolysis ,Rats, Wistar ,Muscle, Skeletal ,030304 developmental biology ,[SDV.MHEP.EM] Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,[SDV.EE.SANT]Life Sciences [q-bio]/Ecology, environment/Health ,0303 health sciences ,Glycogen ,Triglyceride ,Insulin ,Body Weight ,Lipid metabolism ,General Medicine ,Metabolism ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,Lipid Metabolism ,3. Good health ,Rats ,medicine.anatomical_structure ,Endocrinology ,Glucose ,chemistry ,Liver ,13. Climate action ,030220 oncology & carcinogenesis ,Oxidation-Reduction - Abstract
International audience; Background and Aims. Increasing environmental pollution may participate in the growing incidence of metabolic disorders. Static magnetic fields (SMFs) are an emerging environmental health issue due to increased exposure in residential and commercial areas; however, their metabolic effects in serum and skeletal muscle are largely unknown. The aim of this study was to investigate the effect of SMF exposure on glucose and lipid metabolism in serum and skeletal muscles of rats.Methods. Twelve 6-to 7-week-old male Wistar rats were randomly divided into two groups: rats exposed to 128 mT SMF and sham-exposed rats. This moderate-intensity exposure was performed for 1 h/day for 15 consecutive days.Results. Animals exposed to 128 mT SMF displayed significant changes in both glucose (i.e., increases in plasma glucose and lactate and decrease in plasma insulin levels) and lipid (i.e., increases in plasma glycerol, cholesterol and phospholipids but not triglyceride levels) metabolism. During intraperitoneal glucose tolerance tests, SMF-exposed rats displayed significantly higher hyperglycemia compared to sham-exposed rats despite similar insulin levels in both groups. In tissues, SMF exposure induced significant alterations in enzyme activities only in glycolytic muscles and caused a significant decrease in quadriceps and liver glycogen content together with increased phospholipid levels. Conclusions. This study provides evidence that subacute SMF exposure of moderate intensity induces important alterations of glucose and lipid metabolisms, which deserve further investigations to evaluate long-term consequences. Ó
- Published
- 2010
18. Deregulation of hepatic insulin sensitivity induced by central lipid infusion in rats is mediated by nitric oxide
- Author
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Céline Cruciani-Guglielmacci, K. Mezghenna, Maud Soty, René Gross, Carine Zitoun, José Vilar, Nadim Kassis, Christophe Magnan, Bruno Pillot, Nicolas Marsollier, Xavier Fioramonti, Aurélie Joly, Vanessa H. Routh, Gilles Mithieux, Anne-Dominique Lajoix, Amélie Lacombe, Centre de pharmacologie et innovation dans le diabète (CPID), and Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1)
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Hypothalamus ,lcsh:Medicine ,Nitric Oxide Synthase Type I ,Carbohydrate metabolism ,Nitric Oxide ,Nitric oxide ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Insulin resistance ,Internal medicine ,Nutrition/Obesity ,medicine ,Glucose homeostasis ,Animals ,Nitric Oxide Donors ,Enzyme Inhibitors ,lcsh:Science ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Multidisciplinary ,Chemistry ,Physiology/Endocrinology ,Insulin ,lcsh:R ,Fatty acid ,Feeding Behavior ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,medicine.disease ,Rats ,Oleic acid ,Endocrinology ,Glucose ,Liver ,Physiology/Integrative Physiology ,lcsh:Q ,Insulin Resistance ,030217 neurology & neurosurgery ,Oleic Acid ,Research Article - Abstract
International audience; BACKGROUND: Deregulation of hypothalamic fatty acid sensing lead to hepatic insulin-resistance which may partly contribute to further impairment of glucose homeostasis. METHODOLOGY: We investigated here whether hypothalamic nitric oxide (NO) could mediate deleterious peripheral effect of central lipid overload. Thus we infused rats for 24 hours into carotid artery towards brain, either with heparinized triglyceride emulsion (Intralipid, IL) or heparinized saline (control rats). PRINCIPAL FINDINGS: Lipids infusion led to hepatic insulin-resistance partly related to a decreased parasympathetic activity in the liver assessed by an increased acetylcholinesterase activity. Hypothalamic nitric oxide synthases (NOS) activities were significantly increased in IL rats, as the catalytically active neuronal NOS (nNOS) dimers compared to controls. This was related to a decrease in expression of protein inhibitor of nNOS (PIN). Effect of IL infusion on deregulated hepatic insulin-sensitivity was reversed by carotid injection of non selective NOS inhibitor NG-monomethyl-L-arginine (L-NMMA) and also by a selective inhibitor of the nNOS isoform, 7-Nitro-Indazole (7-Ni). In addition, NO donor injection (L-arginine and SNP) within carotid in control rats mimicked lipid effects onto impaired hepatic insulin sensitivity. In parallel we showed that cultured VMH neurons produce NO in response to fatty acid (oleic acid). CONCLUSIONS/SIGNIFICANCE: We conclude that cerebral fatty acid overload induces an enhancement of nNOS activity within hypothalamus which is, at least in part, responsible fatty acid increased hepatic glucose production.
- Published
- 2009
19. Cell-permeable peptide-based disruption of endogenous PKA-AKAP complexes: a tool for studying the molecular roles of AKAP-mediated PKA subcellular anchoring
- Author
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Pierre Petit, Eric Vives, Anne-Dominique Lajoix, Omar M. Faruque, El-Habib Hani, Dominique Bataille, Dung Le-Nguyen, Centre de pharmacologie et innovation dans le diabète (CPID), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
endocrine system ,Cell Membrane Permeability ,Time Factors ,Physiology ,Immunoprecipitation ,A Kinase Anchor Proteins ,Fluorescent Antibody Technique ,Biology ,Exocytosis ,Cell Line ,03 medical and health sciences ,0302 clinical medicine ,Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit ,Insulin-Secreting Cells ,Cyclic AMP ,Animals ,Insulin ,Phosphorylation ,Protein kinase A ,Receptor ,Cyclic AMP Response Element-Binding Protein ,030304 developmental biology ,Mitogen-Activated Protein Kinase 1 ,0303 health sciences ,Mitogen-Activated Protein Kinase 3 ,Nuclear Proteins ,Cell Biology ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,Glucagon ,Peptide Fragments ,Cell biology ,Rats ,Protein Transport ,Glucose ,Biochemistry ,tat Gene Products, Human Immunodeficiency Virus ,Signal transduction ,030217 neurology & neurosurgery ,Intracellular ,Protein Binding ,Signal Transduction - Abstract
International audience; Stimulation of numerous G protein-coupled receptors leads to the elevation of intracellular concentrations of cAMP, which subsequently activates the PKA pathway. Specificity of the PKA signaling module is determined by a sophisticated subcellular targeting network that directs the spatiotemporal activation of the kinase. This specific compartmentalization mechanism occurs through high-affinity interactions of PKA with A-kinase anchoring proteins (AKAPs), the role of which is to target the kinase to discrete subcellular microdomains. Recently, a peptide designated "AKAPis" has been proposed to competitively inhibit PKA-AKAP interactions in vitro. We therefore sought to characterize a cell-permeable construct of the AKAPis inhibitor and use it as a tool to characterize the impact of PKA compartmentalization by AKAPs. Using insulin-secreting pancreatic beta-cells (INS-1 cells), we showed that TAT-AKAPis (at a micromolar range) dose dependently disrupted a significant fraction of endogenous PKA-AKAP interactions. Immunoflurescent analysis also indicated that TAT-AKAPis significantly affected PKA subcellular localization. Furthermore, TAT-AKAPis markedly attenuated glucagon-induced phosphorylations of p44/p42 MAPKs and cAMP response element binding protein, which are downstream effectors of PKA. In parallel, TAT-AKAPis dose dependently inhibited the glucagon-induced potentiation of insulin release. Therefore, AKAP-mediated subcellular compartmentalization of PKA represents a key mechanism for PKA-dependent phosphorylation events and potentiation of insulin secretion in intact pancreatic beta-cells. More interestingly, our data highlight the effectiveness of the cell-permeable peptide-mediated approach to monitoring in cellulo PKA-AKAP interactions and delineating PKA-dependent phosphorylation events underlying specific cellular responses.
- Published
- 2008
20. Chicoric acid, a new compound able to enhance insulin release and glucose uptake
- Author
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Didier Tousch, Pierre Petit, Anne-Dominique Lajoix, Karine Ferrare, Céline Jahannault, Eric Hosy, Gérard Cros, Jacqueline Azay-Milhau, Centre de pharmacologie et innovation dans le diabète (CPID), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
MESH: Muscle Cells ,genetic structures ,Glucose uptake ,medicine.medical_treatment ,Xenopus ,01 natural sciences ,Biochemistry ,Chicory ,chemistry.chemical_compound ,KATP Channels ,Insulin Secretion ,Caffeic acid ,Insulin ,MESH: Animals ,MESH: Xenopus ,0303 health sciences ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,3. Good health ,MESH: Glucose ,Chlorogenic Acid ,medicine.medical_specialty ,endocrine system ,MESH: Rats ,MESH: Caffeic Acids ,MESH: Biological Transport ,Biophysics ,MESH: Insulin ,MESH: Succinates ,Carbohydrate metabolism ,Biology ,MESH: Chlorogenic Acid ,Cell Line ,03 medical and health sciences ,Islets of Langerhans ,Caffeic Acids ,Chlorogenic acid ,Internal medicine ,Diabetes mellitus ,MESH: Hypoglycemic Agents ,medicine ,Animals ,Hypoglycemic Agents ,Molecular Biology ,030304 developmental biology ,MESH: KATP Channels ,Muscle Cells ,MESH: Islets of Langerhans ,Biological Transport ,Succinates ,Cell Biology ,medicine.disease ,In vitro ,0104 chemical sciences ,Rats ,MESH: Cell Line ,010404 medicinal & biomolecular chemistry ,Endocrinology ,Glucose ,chemistry ,Cell culture ,MESH: Chicory - Abstract
International audience; Caffeic acid and chlorogenic acid (CGA), a mono-caffeoyl ester, have been described as potential antidiabetic agents. Using in vitro studies, we report the effects of a dicaffeoyl ester, chicoric acid (CRA) purified from Cichorium intybus, on glucose uptake and insulin secretion. Our results show that CRA and CGA increased glucose uptake in L6 muscular cells, an effect only observed in the presence of stimulating concentrations of insulin. Moreover, we found that both CRA and CGA were able to stimulate insulin secretion from the INS-1E insulin-secreting cell line and rat islets of Langerhans. In the later case, the effect of CRA is only observed in the presence of subnormal glucose levels. Patch clamps studies show that the mechanism of CRA and CGA was different from that of sulfonylureas, as they did not close K(ATP) channels. Chicoric acid is a new potential antidiabetic agent carrying both insulin sensitizing and insulin-secreting properties.
- Published
- 2008
21. P2 purinergic signalling in the pancreatic beta-cell: control of insulin secretion and pharmacology
- Author
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Pierre Petit, René Gross, Anne-Dominique Lajoix, Centre de pharmacologie et innovation dans le diabète (CPID), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
P2Y receptor ,medicine.medical_treatment ,Pharmaceutical Science ,Biology ,Pharmacology ,03 medical and health sciences ,Islets of Langerhans ,0302 clinical medicine ,Adenosine Triphosphate ,Insulin Secretion ,medicine ,Animals ,Humans ,Insulin ,Receptor ,030304 developmental biology ,0303 health sciences ,Receptors, Purinergic P2 ,Purinergic receptor ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,Purinergic signalling ,3. Good health ,Metabotropic receptor ,030220 oncology & carcinogenesis ,Signal transduction ,Ionotropic effect ,Signal Transduction - Abstract
International audience; Extracellular adenosine triphosphate is able to modulate pancreatic beta-cell function, acting on P2 purinergic ionotropic (P2X) and metabotropic (P2Y) receptors. Physiologically, ATP entrains beta-cells into a common rhythm by coordinating Ca(2+) oscillations; it plays a central role in insulin secretion pulsatility. ATP also triggers a positive feedback signal amplifying glucose-induced insulin release, which argues for a potential pharmacological application. ATP has consistently been shown to increase cytoplasmic free calcium concentration, notably in human tissue. Acting on P2X receptors, of which different molecular subtypes are expressed in beta-cells, it leads to a transient insulin release that may involve a closure of K(ATP) channels or a rapidly decaying inward current. Activation of G-protein-coupled P2Y receptors triggers different signalling pathways and amplifies insulin release in a glucose-dependent way. It has recently been shown that pancreatic beta-cells express different molecular subtypes of receptors, which may explain the complex interaction of P2Y ligands on high- and low-affinity binding sites. Despite the complexity of this purinergic pharmacology, consistent pre-clinical data suggest the potential of P2Y receptor agonists as drug candidates for type 2 diabetes.
- Published
- 2008
22. ERK1/2 control phosphorylation and protein level of cAMP-responsive element-binding protein: a key role in glucose-mediated pancreatic beta-cell survival
- Author
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Safia, Costes, Christophe, Broca, Gyslaine, Bertrand, Anne-Dominique, Lajoix, Dominique, Bataille, Joel, Bockaert, Stéphane, Dalle, Centre de pharmacologie et innovation dans le diabète (CPID), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Male ,MESH: Genes, bcl-2 ,MESH: Sulfonamides ,Gene Expression ,Apoptosis ,MESH: RNA, Small Interfering ,MESH: Protein Kinase Inhibitors ,MESH: Animals ,Phosphorylation ,RNA, Small Interfering ,Mitogen-Activated Protein Kinase 1 ,Sulfonamides ,Mitogen-Activated Protein Kinase 3 ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,CREB-Binding Protein ,MESH: Glucose ,Proto-Oncogene Proteins c-bcl-2 ,MESH: Cell Survival ,MESH: Microscopy, Electron, Transmission ,MESH: Mitogen-Activated Protein Kinase 3 ,MESH: Mitogen-Activated Protein Kinase 1 ,MESH: Gene Expression ,MESH: Rats ,Cell Survival ,MESH: CREB-Binding Protein ,MESH: Cyclic AMP-Dependent Protein Kinases ,Transfection ,Cell Line ,Islets of Langerhans ,Microscopy, Electron, Transmission ,MESH: Isoquinolines ,Animals ,RNA, Messenger ,Rats, Wistar ,Protein Kinase Inhibitors ,MESH: RNA, Messenger ,Flavonoids ,MESH: Phosphorylation ,MESH: Apoptosis ,MESH: Islets of Langerhans ,MESH: Transfection ,MESH: Rats, Wistar ,Isoquinolines ,Cyclic AMP-Dependent Protein Kinases ,MESH: Male ,Genes, bcl-2 ,Rats ,MESH: Cell Line ,Glucose ,MESH: Proto-Oncogene Proteins c-bcl-2 ,MESH: Flavonoids - Abstract
cAMP-responsive element-binding protein (CREB) is required for beta-cell survival by regulating expression of crucial genes such as bcl-2 and IRS-2. Using MIN6 cells and isolated rat pancreatic islets, we investigated the signaling pathway that controls phosphorylation and protein level of CREB. We observed that 10 mmol/l glucose-induced CREB phosphorylation was totally inhibited by the protein kinase A (PKA) inhibitor H89 (2 micromol/l) and reduced by 50% with the extracellular signal-regulated kinase (ERK)1/2 inhibitor PD98059 (20 micromol/l). This indicates that ERK1/2, reported to be located downstream of PKA, participates in the PKA-mediated CREB phosphorylation elicited by glucose. In ERK1/2-downregulated MIN6 cells by siRNA, glucose-stimulated CREB phosphorylation was highly reduced and CREB protein content was decreased by 60%. In MIN6 cells and islets cultured for 24-48 h in optimal glucose concentration (10 mmol/l), which promotes survival, blockade of ERK1/2 activity with PD98059 caused a significant decrease in CREB protein level, whereas CREB mRNA remained unaffected (measured by real-time quantitative PCR). This was associated with loss of bcl-2 mRNA and protein contents, caspase-3 activation, and emergence of ultrastructural apoptotic features detected by electron microscopy. Our results indicate that ERK1 and -2 control the phosphorylation and protein level of CREB and play a key role in glucose-mediated pancreatic beta-cell survival.
- Published
- 2006
23. Miniglucagon (MG)-generating endopeptidase, which processes glucagon into MG, is composed of N-arginine dibasic convertase and aminopeptidase B
- Author
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Sandrine Cadel, Stéphane Dalle, Anne-Dominique Lajoix, Ghislaine Fontés, Annik Prat, Dung Le-Nguyen, Florence Tribillac, Thierry Foulon, François Bergeron, René Gross, Dominique Bataille, Institut de Génomique Fonctionnelle (IGF), Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 1 (UM1)-Université de Montpellier (UM), and Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
medicine.medical_specialty ,endocrine system ,Arginine ,Biology ,Aminopeptidases ,Glucagon ,Aminopeptidase ,Substrate Specificity ,Islets of Langerhans ,Mice ,03 medical and health sciences ,Aminopeptidase B ,0302 clinical medicine ,Endocrinology ,Internal medicine ,Endopeptidases ,Nardilysin ,medicine ,Animals ,Protease Inhibitors ,Cells, Cultured ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,Metalloendopeptidases ,Cobalt ,[SDV.MHEP.EM]Life Sciences [q-bio]/Human health and pathology/Endocrinology and metabolism ,Hypoglycemia ,Peptide Fragments ,Recombinant Proteins ,Endopeptidase ,3. Good health ,Zinc ,Enzyme ,chemistry ,Biochemistry ,Cell culture ,Calcium ,030217 neurology & neurosurgery ,Phenanthrolines - Abstract
Miniglucagon (MG), the C-terminal glucagon fragment, processed from glucagon by the MG-generating endopeptidase (MGE) at the Arg17-Arg18 dibasic site, displays biological effects opposite to that of the mother-hormone. This secondary processing occurs in the glucagon- and MG-producing alpha-cells of the islets of Langerhans and from circulating glucagon. We first characterized the enzymatic activities of MGE in culture media from glucagon and MG-secreting alphaTC1.6 cells as made of a metalloendoprotease and an aminopeptidase. We observed that glucagon is a substrate for N-arginine dibasic convertase (NRDc), a metalloendoprotease, and that aminopeptidase B cleaves in vitro the intermediate cleavage products sequentially, releasing mature MG. Furthermore, immunodepletion of either enzyme resulted in the disappearance of the majority of MGE activity from the culture medium. We found RNAs and proteins corresponding to both enzymes in different cell lines containing a MGE activity (mouse alphaTC1.6 cells, rat hepatic FaO, and rat pituitary GH4C1). Using confocal microscopy, we observed a granular immunostaining of both enzymes in the alphaTC1.6 and native rat alpha-cells from islets of Langerhans. By immunogold electron microscopy, both enzymes were found in the mature secretory granules of alpha-cells, close to their substrate (glucagon) and their product (MG). Finally, we found NRDc only in the fractions from perfused pancreas that contain glucagon and MG after stimulation by hypoglycemia. We conclude that MGE is composed of NRDc and aminopeptidase B acting sequentially, providing a molecular basis for this uncommon regulatory process, which should be now addressed in both physiological and pathophysiological situations.
- Published
- 2005
24. Cellulose membrane supported peptide arrays for deciphering protein-protein interaction sites: the case of PIN, a protein with multiple natural partners
- Author
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René Gross, Claude Granier, Daniel Laune, Anne-Dominique Lajoix, Cindy Aknin, and Samuel Dietz
- Subjects
Scaffold protein ,Cytoplasmic Dyneins ,Protein Conformation ,Dynein ,Molecular Sequence Data ,Myosin Type V ,Protein Array Analysis ,Peptide ,Nitric Oxide Synthase Type I ,Biology ,Catalysis ,Protein–protein interaction ,Inorganic Chemistry ,chemistry.chemical_compound ,Peptide Library ,Drug Discovery ,Myosin ,Aromatic amino acids ,Animals ,Amino Acid Sequence ,Physical and Theoretical Chemistry ,Cellulose ,Molecular Biology ,Transcription factor ,chemistry.chemical_classification ,Binding Sites ,Organic Chemistry ,Dyneins ,Proteins ,General Medicine ,Peptide Fragments ,Amino acid ,Rats ,chemistry ,Biochemistry ,Biophysics ,Indicators and Reagents ,Nitric Oxide Synthase ,Information Systems ,Protein Binding - Abstract
Cellulose membrane supported peptide arrays, prepared according to the Spot method, allow the rapid identification and characterization of protein-protein interaction sites. Here, the method was used to screen reactive peptides from different proteins that bind to a single molecule, the PIN protein. PIN possesses two binding grooves, that have been shown to interact with several targets, including neuronal NO synthase, dynein intermediate chain, myosin V, the proapoptotic protein Bim, the scaffolding proteins DAP1alpha and gephyrin, and the transcription factor NRF-1. Arrays of peptides representing sequences of these targets were probed for reactivity with GST-tagged PIN, enabling the precise identification of binding motifs. Binding motifs were then minimized to seven or eight amino acid long peptides: YSKETQT for dynein IC, CDKSTQT for Bim, KDTGIQVD for nNOS, QSVGVQV for DAP1alpha and EDKNTMTD for myosin V. Alascan and substitution analysis provided proof that the Gln residue is critical for the interaction and cannot be easily replaced. Positions -1 and +1, just flanking the pivotal Gln, are also important; they consist of hydrophobic residues (Thr, Val) that could only be replaced by hydrophobic or aromatic amino acids. Position -4 is also critical for binding, with its Asp or Ser being replaceable to some extent. Alignment of sequences of proteins known to bind PIN shows that the most frequent amino acids in the motif are DKGTQT, consistent with the Spot results. We postulate that the degenerate character of binding to PIN is based on the propensity of several sequences to adopt a beta-strand conformation that allows the Gln residue to position itself in the PIN channel and on the conformational breathing of the PIN binding groove.
- Published
- 2004
25. Miniglucagon (glucagon 19-29): a novel regulator of the pancreatic islet physiology
- Author
-
Stéphane, Dalle, Ghislaine, Fontés, Anne-Dominique, Lajoix, Laurence, LeBrigand, René, Gross, Gérard, Ribes, Michel, Dufour, Léo, Barry, Dung, LeNguyen, and Dominique, Bataille
- Subjects
Male ,Islets of Langerhans ,Microscopy, Electron ,Immune Sera ,Insulin Secretion ,Animals ,Fluorescent Antibody Technique ,Insulin ,In Vitro Techniques ,Rats, Wistar ,Glucagon ,Peptide Fragments ,Rats - Abstract
Miniglucagon, the COOH-terminal (19-29) fragment processed from glucagon, is a potent and efficient inhibitor of insulin secretion from the MIN 6 beta-cell line. Using the rat isolated-perfused pancreas, we investigated the inhibitory effect of miniglucagon on insulin secretion and evaluated the existence of an inhibitory tone exerted by this peptide inside the islet. Miniglucagon dose-dependently inhibited insulin secretion stimulated by 8.3 mol/l glucose, with no change in the perfusion flow rate. A concentration of 1 nmol/l miniglucagon had a significant inhibitory effect on a 1 nmol/l glucagon-like peptide 1 (7-36) amide-potentiated insulin secretion. A decrease in extracellular glucose concentration simultaneously stimulated glucagon and miniglucagon secretion from pancreatic alpha-cells. Using confocal and electron microscopy analysis, we observed that miniglucagon is colocalized with glucagon in mature secretory granules of alpha-cells. Perfusion of an anti-miniglucagon antiserum directed against the biologically active moiety of the peptide resulted in a more pronounced effect of a glucose challenge on insulin secretion, indicating that miniglucagon exerts a local inhibitory tone on beta-cells. We concluded that miniglucagon is a novel local regulator of the pancreatic islet physiology and that any abnormal inhibitory tone exerted by this peptide on the beta-cell would result in an impaired insulin secretion, as observed in type 2 diabetes.
- Published
- 2002
26. Possible Protective Effect of Membrane Lipid Rafts against Interleukin-1β-Mediated Anti-Proliferative Effect in INS-1 Cells
- Author
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René Gross, Anne Dominique Lajoix, Sylvie Peraldi-Roux, Caroline Guzman, Moustafa Hamze, Myriam Chentouf, Biocommunication en Cardio-Métabolique (BC2M), Université de Montpellier (UM), Centre de pharmacologie et innovation dans le diabète (CPID), Centre National de la Recherche Scientifique (CNRS)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Université Montpellier 1 (UM1), and Université Montpellier 1 (UM1)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Programmed cell death ,Physiology ,Interleukin-1beta ,Gene Expression ,Nitric Oxide Synthase Type II ,lcsh:Medicine ,Apoptosis ,[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,Biology ,Cell Line ,03 medical and health sciences ,Membrane Microdomains ,0302 clinical medicine ,Cell Signaling ,Downregulation and upregulation ,Insulin-Secreting Cells ,Immune Physiology ,Medicine and Health Sciences ,Diabetes Mellitus ,medicine ,Animals ,Insulin ,lcsh:Science ,Lipid raft ,Cell Proliferation ,030304 developmental biology ,Receptors, Interleukin-1 Type I ,0303 health sciences ,Multidisciplinary ,Caspase 3 ,Cell growth ,Pancreatic islets ,lcsh:R ,Biology and Life Sciences ,Cell Biology ,Lipid signaling ,Rats ,Type 2 Diabetes ,Cell biology ,medicine.anatomical_structure ,Membrane protein ,Metabolic Disorders ,030220 oncology & carcinogenesis ,Cytokines ,lcsh:Q ,Transcription Factor CHOP ,Research Article ,Signal Transduction - Abstract
International audience; We recently reported that pancreatic islets from pre-diabetic rats undergo an inflammatory process in which IL-1β takes part and controls β-cell function. In the present study, using the INS-1 rat pancreatic β-cell line, we investigated the potential involvement of membrane-associated cholesterol-enriched lipid rafts in IL-1β signaling and biological effects on insulin secretion, β-cell proliferation and apoptosis. We show that, INS-1 cells exposure to increasing concentrations of IL-1β leads to a progressive inhibition of insulin release, an increase in the number of apoptotic cells and a dose-dependent decrease in pancreatic β-cell proliferation. Disruption of membrane lipid rafts markedly reduced glucose-stimulated insulin secretion but did not affect either cell apoptosis or proliferation rate, demonstrating that membrane lipid raft integrity is essential for β-cell secretory function. In the same conditions, IL-1β treatment of INS-1 cells led to a slight further decrease in insulin secretion for low concentrations of the cytokine, and a more marked one, similar to that observed in normal cells for higher concentrations. These effects occurred together with an increase in iNOS expression and surprisingly with an upregulation of tryptophane hydroxylase and protein Kinase C in membrane lipid rafts suggesting that compensatory mechanisms develop to counteract IL-1β inhibitory effects. We also demonstrate that disruption of membrane lipid rafts did not prevent cytokine-induced cell death recorded after exposure to high IL-1β concentrations. Finally, concerning cell proliferation, we bring strong evidence that membrane lipid rafts exert a protective effect against IL-1β anti-proliferative effect, possibly mediated at least partly by modifications in ERK and PKB expression/activities. Our results 1) demonstrate that IL-1β deleterious effects do not require a cholesterol-dependent plasma membrane compartmentalization of IL-1R1 signaling and 2) confer to membrane lipid rafts integrity a possible protective function that deserves to be considered in the context of inflammation and especially T2D pathogenesis.
- Published
- 2014
27. A constitutive nitric oxide synthase modulates insulin secretion in the INS-1 cell line
- Author
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Samuel Dietz, René Gross, P Beffy, Pellegrino Masiello, Thierry Chardès, Anne-Dominique Lajoix, Sylvie Peraldi-Roux, Gérard Ribes, Biologie Intégrative et Virologie des Insectes [Univ. de Montpellier II] (BIVI), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de la Recherche Agronomique (INRA)
- Subjects
Gene isoform ,medicine.medical_specialty ,Arginine ,medicine.medical_treatment ,[SDV]Life Sciences [q-bio] ,Nitric Oxide Synthase Type I ,Nitric Oxide ,Biochemistry ,Potassium Chloride ,Endocrinology ,Internal medicine ,Insulin Secretion ,medicine ,CELLULE INS-1 ,Tumor Cells, Cultured ,Animals ,Insulin ,Secretion ,INS-1 cells ,Enzyme Inhibitors ,INS-1 cells, Insulin secretion, Neuronal nitric oxide synthase ,Molecular Biology ,Neuronal nitric oxide synthase ,biology ,Pancreatic islets ,Rat Insulinoma ,Succinates ,NOS ,Rats ,Nitric oxide synthase ,Isoenzymes ,Pancreatic Neoplasms ,medicine.anatomical_structure ,Glucose ,NG-Nitroarginine Methyl Ester ,Microscopy, Fluorescence ,Cell culture ,biology.protein ,Insulinoma ,Nitric Oxide Synthase - Abstract
We provide immunocytochemical evidence that the neuronal isoform of constitutive NO synthase (cNOS) is expressed in the rat insulinoma cell line INS-1. Furthermore, using Nω-nitro- l -arginine methyl ester ( l -NAME), a pharmacological inhibitor of cNOS activity, we show that this enzyme is implicated in the modulation of insulin secretion in INS-1 cells. Indeed, in the presence of 2.8 mM glucose, l -NAME induced a specific and dose-dependent increase in insulin release, suggesting that cNOS exerts an inhibitory tone on basal insulin secretion. Moreover, l -arginine, the physiological substrate of cNOS, significantly reduced the marked enhancing effect of l -NAME on insulin release and to a lesser extent, at low concentrations, that of 10 mM KCl. l -NAME also potentiated the insulin secretion stimulated by 5.5 and 8.3 mM glucose, but in this case, its effect was not reduced by l -arginine. In conclusion, our data show that the neuronal isoform of cNOS exerts a negative modulation on insulin secretion in INS-1 cells, confirming the previous results obtained in the isolated perfused rat pancreas or pancreatic islets.
- Published
- 2001
28. Synaptotagmin 11 interacts with components of the RNA-induced silencing complex RISC in clonal pancreatic β-cells
- Author
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Carole Monterrat, Laetitia Coudert, Jean-Marie Schmitter, J. Papin, Itsaso Garcia-Arcos, Valérie Lagrée, Begoña Ochoa, Jochen Lang, Marie-Noëlle Benassy, Alexandra Milochau, Stéphane Chaignepain, and Anne Dominique Lajoix
- Subjects
Male ,endocrine system ,SND1 ,Protein family ,RNA-induced silencing complex ,Biophysics ,Pancreatic Islets ,Biology ,Secretory pathway ,Biochemistry ,Synaptotagmin 1 ,Cell Line ,Synaptotagmins ,Fragile X Mental Retardation Protein ,Mice ,Structural Biology ,Insulin-Secreting Cells ,Protein Interaction Mapping ,Genetics ,Gene silencing ,Animals ,RNA-Induced Silencing Complex ,Rats, Wistar ,Molecular Biology ,Regulation of gene expression ,Nuclear Proteins ,ER-Golgi ,RISC ,Cell Biology ,Endonucleases ,Molecular biology ,Transmembrane protein ,Cell biology ,Rats ,MicroRNAs ,Protein Transport ,SNARE ,Argonaute Proteins ,RNA Interference ,Protein Binding - Abstract
Synaptotagmins are two C2 domain-containing transmembrane proteins. The function of calcium-sensitive members in the regulation of post-Golgi traffic has been well established whereas little is known about the calcium-insensitive isoforms constituting half of the protein family. Novel binding partners of synaptotagmin 11 were identified in β-cells. A number of them had been assigned previously to ER/Golgi derived-vesicles or linked to RNA synthesis, translation and processing. Whereas the C2A domain interacted with the Q-SNARE Vti1a, the C2B domain of syt11 interacted with the SND1, Ago2 and FMRP, components of the RNA-induced silencing complex (RISC). Binding to SND was direct via its N-terminal tandem repeats. Our data indicate that syt11 may provide a link between gene regulation by microRNAs and membrane traffic.
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