title: Regulation of glycolysis and expression of glucose metabolism-related genes by reactive oxygen species in contracting skeletal muscle cells.
abstract: Contractile activity induces a marked increase in glycolytic activity and gene expression of enzymes and transporters involved in glucose metabolism in skeletal muscle. Muscle contraction also increases the production of reactive oxygen species (ROS). In this study, the effects of treatment with N-acetylcysteine (NAC), a potent antioxidant compound, on contraction-stimulated glycolysis were investigated in electrically stimulated primary rat skeletal muscle cells. The following parameters were measured: 2-[(3)H]deoxyglucose (2-DG) uptake; activities of hexokinase, phosphofructokinase (PFK), and glucose-6-phosphate dehydrogenase (G6PDH); lactate production; and expression of the glucose transporter 4 (GLUT4), hexokinase II (HKII), and PFK genes after one bout of electrical stimulation in primary rat myotubes. NAC treatment decreased ROS signal by 49% in resting muscle cells and abolished the muscle contraction-induced increase in ROS levels. In resting cells, NAC decreased mRNA and protein contents of GLUT4, mRNA content and activity of PFK, and lactate production. NAC treatment suppressed the contraction-mediated increase in 2-DG uptake; lactate production; hexokinase, PFK, and G6PDH activities; and gene expression of GLUT4, HKII, and PFK. Similar to muscle contraction, exogenous H(2)O(2) (500 nM) administration increased 2-DG uptake; lactate production; hexokinase, PFK, and G6PDH activities; and gene expression of GLUT4, HKII, and PFK. These findings support the proposition that ROS endogenously produced play an important role in the changes in glycolytic activity and gene expression of GLUT4, HKII, and PFK induced by contraction in skeletal muscle cells.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil. chjpinheiro@gmail.com
authors.forename: Carlos Hermano da Justa
authors.initials: CH
authors.lastname: Pinheiro
authors.forename: Leonardo R
authors.initials: LR
authors.lastname: Silveira
authors.forename: Renato Tadeu
authors.initials: RT
authors.lastname: Nachbar
authors.forename: Kaio Fernando
authors.initials: KF
authors.lastname: Vitzel
authors.forename: Rui
authors.initials: R
authors.lastname: Curi
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002478:Cells, Cultured; D003847:Deoxyglucose / Q000378:metabolism; D004558:Electric Stimulation; D005947:Glucose / Q000235:genetics / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects; D006593:Hexokinase / Q000235:genetics / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D025203:Phosphofructokinase-1, Muscle Type / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D051275:Glucose Transporter Type 4; D017382:Reactive Oxygen Species; D003847:Deoxyglucose; D005954:Glucosephosphate Dehydrogenase; D025203:Phosphofructokinase-1, Muscle Type; D006593:Hexokinase; D005947:Glucose; D000111:Acetylcysteine