title: Oxidative stress of myosin contributes to skeletal muscle dysfunction in rats with chronic heart failure.
abstract: Intrinsic muscle abnormalities affecting skeletal muscle are often reported during chronic heart failure (CHF). Because myosin is the molecular motor of force generation, we sought to determine whether its dysfunction contributes to skeletal muscle weakness in CHF and, if so, to identify the underlying causative factors. Severe CHF was induced in rats by aortic stenosis. In diaphragm and soleus muscles, we investigated in vitro mechanical performance, myosin-based actin filament motility, myosin heavy (MHC) and light (MLC) chain isoform compositions, MLC integrity, caspase-3 activation, and oxidative damage. Diaphragm and soleus muscles from CHF exhibited depressed mechanical performance. Myosin sliding velocities were 16 and 20% slower in CHF than in sham in diaphragm (1.9 +/- 0.1 vs. 1.6 +/- 0.1 microm/s) and soleus (0.6 +/- 0.1 vs. 0.5 +/- 0.1 microm/s), respectively (each P < 0.05). The ratio of slow-to-fast myosin isoform did not differ between sham and CHF. Immunoblots with anti-MLC antibodies did not detect the presence of protein fragments, and no activation of caspase-3 was evidenced. Immunolabeling revealed oxidative damage in CHF muscles, and MHC was the main oxidized protein. Lipid peroxidation and expression of oxidized MHC were significantly higher in CHF than in shams. In vitro myosin exposure to increasing ONOO(-) concentrations was associated with an increasing amount of oxidized MHC and a reduced myosin velocity. These data provide experimental evidence that intrinsic myosin dysfunction occurs in CHF and may be related to oxidative damage to myosin.
authors.affiliation: INSERM U689, Centre de Recherche Cardiovasculaire INSERM, Hôpital Lariboisière, 41 Bd de la Chapelle, 75475 Paris Cedex 10, France. coirault@larib.inserm.fr
authors.forename: Catherine
authors.initials: C
authors.lastname: Coirault
authors.forename: Aziz
authors.initials: A
authors.lastname: Guellich
authors.forename: Thomas
authors.initials: T
authors.lastname: Barbry
authors.forename: Jane Lise
authors.initials: JL
authors.lastname: Samuel
authors.forename: Bruno
authors.initials: B
authors.lastname: Riou
authors.forename: Yves
authors.initials: Y
authors.lastname: Lecarpentier
mesh_terms: D000818:Animals; D003964:Diaphragm / Q000503:physiopathology; D004195:Disease Models, Animal; D006333:Heart Failure / Q000378:metabolism / Q000503:physiopathology*; D015227:Lipid Peroxidation; D008297:Male; D020409:Molecular Motor Proteins / Q000378:metabolism; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D018994:Myosin Light Chains / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D050050:Protein Carbonylation; D051381:Rats; D017208:Rats, Wistar; D024744:Skeletal Muscle Myosins / Q000378:metabolism*
chemical_list: D020409:Molecular Motor Proteins; D018994:Myosin Light Chains; D024744:Skeletal Muscle Myosins; D018995:Myosin Heavy Chains