title: Modulation of p38 mitogen-activated protein kinase cascade and metalloproteinase activity in diaphragm muscle in response to free radical scavenger administration in dystrophin-deficient Mdx mice.
abstract: Duchenne muscular dystrophy muscles undergo increased oxidative stress and altered calcium homeostasis, which contribute to myofiber loss by trigging both necrosis and apoptosis. Here, we asked whether treatment with free radical scavengers could improve the dystrophic pattern of mdx muscles. Five-week-old mdx mice were treated for 2 weeks with alpha-lipoic acid/l-carnitine. This treatment decreased the plasmatic creatine kinase level, the antioxidant enzyme activity, and lipid peroxidation products in mdx diaphragm. Free radical scavengers also modulated the phosphorylation/activity of some component of the mitogen-activated protein kinase (MAPK) cascades: p38 MAPK, the extracellular signal-related kinase, and the Jun kinase. beta-Dystroglycan (beta-DG), a multifunctional adaptor or scaffold capable of interacting with components of the extracellular signal-related kinase-MAP kinase cascade, was also affected after treatment. In the mdx muscles, beta-DG (43 kd) was cleaved by matrix metalloproteinases into a 30-kd form (beta-DG30). We show that the proinflammatory protein nuclear factor-kappaB activator decreased after the treatment, leading to a significant reduction of matrix metalloproteinase activity in the mdx diaphragm. Our data highlight the implication of oxidative stress and cell signaling defects in dystrophin-deficient muscle via the MAP kinase cascade-beta-DG interaction and nuclear factor-kappaB-mediated inflammation process.
authors.affiliation: Institut National de la Santé, et de la Recherche Médicale, Equipe ERI 25, Muscle et Pathologies, Université de Montpellier1, Unité de Formation et de Recherche de Médecine, EA701, 4 Boulevard Henri IV, 34060 Montpellier, France.
authors.forename: Karim
authors.initials: K
authors.lastname: Hnia
authors.forename: Gerald
authors.initials: G
authors.lastname: Hugon
authors.forename: François
authors.initials: F
authors.lastname: Rivier
authors.forename: Ahmed
authors.initials: A
authors.lastname: Masmoudi
authors.forename: Jacques
authors.initials: J
authors.lastname: Mercier
authors.forename: Dominique
authors.initials: D
authors.lastname: Mornet
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D002331:Carnitine / Q000494:pharmacology*; D003402:Creatine Kinase / Q000378:metabolism; D003964:Diaphragm / Q000201:enzymology / Q000473:pathology; D049030:Dystroglycans / Q000378:metabolism; D016189:Dystrophin / Q000172:deficiency; D016166:Free Radical Scavengers / Q000494:pharmacology*; D007249:Inflammation / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D051379:Mice; D018101:Mice, Inbred mdx; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism; D009336:Necrosis / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D016759:Oncogene Protein p65(gag-jun) / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D008063:Thioctic Acid / Q000494:pharmacology*; D014803:Vitamin B Complex / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D016189:Dystrophin; D016166:Free Radical Scavengers; D016328:NF-kappa B; D016759:Oncogene Protein p65(gag-jun); D014803:Vitamin B Complex; D049030:Dystroglycans; D008063:Thioctic Acid; D048051:p38 Mitogen-Activated Protein Kinases; D003402:Creatine Kinase; D020782:Matrix Metalloproteinases; D002331:Carnitine; D002118:Calcium