Production of interleukin-6 by skeletal myotubes: role of reactive oxygen species.
In the present study we have tested the ability of reactive oxygen species (ROS) to stimulate the production of interleukin (IL)- 6 from skeletal myocytes. Differentiated C2C12 murine skeletal muscle cells (myotubes) exposed to pyrogallol (PYR), xanthine/ xanthine-oxidase (X/XO), or H(2)O(2) for 24 h exhibited a concentration-dependent increase in IL-6 production. Unlike myotubes, incubation of myoblasts and endothelial cells with X/XO or PYR did not result in increased IL-6 release. In myotubes, superoxide dismutase and catalase blocked the ROS-induced IL-6 release. Exposure of myotubes to H(2)O(2) increased steady-state IL-6 mRNA levels, and pretreatment of myotubes with actinomycin D or cycloheximide abolished the ROS-induced IL-6 production. In addition, pretreatment of cells with N-acetyl-cysteine blocked tumor necrosis factor (TNF)-alpha-induced IL-6 release, suggesting that endogenously produced ROS participate in IL-6 production. Myotubes stimulated with H(2)O(2) exhibited increased I kappa B-alpha phosphorylation and degradation, and treatment of C2C12 with ROS-generating agents increased activator protein (AP)-1 and nuclear factor (NF)-kappa B-dependent promoter activity. Finally, preincubation of myotubes with the pharmacologic inhibitor of NF-kappa B, diethyldithiocarbamate, or transient transfection with an I kappa B-alpha mutant, inhibited the ROS-stimulated IL-6 release. In conclusion, ROS stimulate IL-6 production from skeletal myotubes in a manner that involves transcriptional activation of the IL-6 gene through an NF-kappa B-dependent pathway.
Kosmidou
Ioanna
I
George P. Livanos Laboratory, Evangelismos Hospital, Department of Critical Care and Pulmonary Services, University of Athens, Athens, Greece.
Vassilakopoulos
Theodoros
T
Xagorari
Angeliki
A
Zakynthinos
Spyros
S
Papapetropoulos
Andreas
A
Roussos
Charis
C
D000818:Animals; D002460:Cell Line; D004050:Ditiocarb / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D011748:Pyrogallol / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000494:pharmacology; D019820:Xanthine / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D015850:Interleukin-6; D016328:NF-kappa B; D016877:Oxidants; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D011748:Pyrogallol; D019820:Xanthine; D004050:Ditiocarb; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases