title: Pharmacological Blockade of Cannabinoid CB1 Receptors in Diet-Induced Obesity Regulates Mitochondrial Dihydrolipoamide Dehydrogenase in Muscle.
abstract: Cannabinoid CB1 receptors peripherally modulate energy metabolism. Here, we investigated the role of CB1 receptors in the expression of glucose/pyruvate/tricarboxylic acid (TCA) metabolism in rat abdominal muscle. Dihydrolipoamide dehydrogenase (DLD), a flavoprotein component (E3) of α-ketoacid dehydrogenase complexes with diaphorase activity in mitochondria, was specifically analyzed. After assessing the effectiveness of the CB1 receptor antagonist AM251 (3 mg kg(-1), 14 days) on food intake and body weight, we could identified seven key enzymes from either glycolytic pathway or TCA cycle--regulated by both diet and CB1 receptor activity--through comprehensive proteomic approaches involving two-dimensional electrophoresis and MALDI-TOF/LC-ESI trap mass spectrometry. These enzymes were glucose 6-phosphate isomerase (GPI), triosephosphate isomerase (TPI), enolase (Eno3), lactate dehydrogenase (LDHa), glyoxalase-1 (Glo1) and the mitochondrial DLD, whose expressions were modified by AM251 in hypercaloric diet-induced obesity. Specifically, AM251 blocked high-carbohydrate diet (HCD)-induced expression of GPI, TPI, Eno3 and LDHa, suggesting a down-regulation of glucose/pyruvate/lactate pathways under glucose availability. AM251 reversed the HCD-inhibited expression of Glo1 and DLD in the muscle, and the DLD and CB1 receptor expression in the mitochondrial fraction. Interestingly, we identified the presence of CB1 receptors at the membrane of striate muscle mitochondria. DLD over-expression was confirmed in muscle of CB1-/- mice. AM251 increased the pyruvate dehydrogenase and glutathione reductase activity in C2C12 myotubes, and the diaphorase/oxidative activity in the mitochondria fraction. These results indicated an up-regulation of methylglyoxal and TCA cycle activity. Findings suggest that CB1 receptors in muscle modulate glucose/pyruvate/lactate pathways and mitochondrial oxidative activity by targeting DLD.
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Arrabal
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Lucena
authors.affiliation: Department of Neurosciences, University of the Basque Country UPV/EHU, Leioa, Spain.
authors.forename: Miren Josune
authors.initials: MJ
authors.lastname: Canduela
authors.affiliation: Department of Neurosciences, University of the Basque Country UPV/EHU, Leioa, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Ramos-Uriarte
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Rivera
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Antonia
authors.initials: A
authors.lastname: Serrano
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Pavón
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Decara
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Vargas
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Baixeras
authors.affiliation: ECAI de Proteómica, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, Málaga, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Martín-Rufián
authors.affiliation: Departamento de Biología Molecular y Bioquímica, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, Málaga, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Márquez
authors.affiliation: Departamento de Biología Celular, Genética y Fisiología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, Málaga, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Fernández-Llébrez
authors.affiliation: University of Aberdeen, Rowett Institute of Nutrition & Health, Aberdeen, United Kingdom.
authors.forename: Baukje
authors.initials: B
authors.lastname: De Roos
authors.affiliation: Department of Neurosciences, University of the Basque Country UPV/EHU, Leioa, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Grandes
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodríguez de Fonseca
authors.affiliation: UGC Salud Mental, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga-Hospital Universitario Regional de Málaga, Málaga, Spain.|CIBER OBN, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Suárez
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002460:Cell Line; D004032:Diet; D004040:Dietary Carbohydrates; D008058:Dihydrolipoamide Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D005247:Feeding Behavior / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000201:enzymology; D009132:Muscles / Q000187:drug effects / Q000201:enzymology*; D009765:Obesity / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D019289:Pyruvic Acid / Q000378:metabolism; D017208:Rats, Wistar; D043884:Receptor, Cannabinoid, CB1 / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004040:Dietary Carbohydrates; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; C103505:AM 251; D019289:Pyruvic Acid; D008058:Dihydrolipoamide Dehydrogenase; D005980:Glutathione Reductase; D005947:Glucose