title: Cytokine response of cultured skeletal muscle cells stimulated with proinflammatory factors depends on differentiation stage.
abstract: Myoblast proliferation and myotube formation are critical early events in skeletal muscle regeneration. The attending inflammation and cytokine signaling are involved in regulation of skeletal muscle cell proliferation and differentiation. Secretion of muscle-derived cytokines upon exposure to inflammatory factors may depend on the differentiation stage of regenerating muscle cells. Cultured human myoblasts and myotubes were exposed to 24-hour treatment with tumor necrosis factor (TNF)- α or lipopolysaccharide (LPS). Secretion of interleukin 6 (IL-6), a major muscle-derived cytokine, and interleukin 1 (IL-1), an important regulator of inflammatory response, was measured 24 hours after termination of TNF- α or LPS treatment. Myoblasts pretreated with TNF- α or LPS displayed robustly increased IL-6 secretion during the 24-hour period after removal of treatments, while IL-1 secretion remained unaltered. IL-6 secretion was also increased in myotubes, but the response was less pronounced compared with myoblasts. In contrast to myoblasts, IL-1 secretion was markedly stimulated in LPS-pretreated myotubes. We demonstrate that preceding exposure to inflammatory factors stimulates a prolonged upregulation of muscle-derived IL-6 and/or IL-1 in cultured skeletal muscle cells. Our findings also indicate that cytokine response to inflammatory factors in regenerating skeletal muscle partially depends on the differentiation stage of myogenic cells.
authors.affiliation: Centre for Intensive Care Medicine, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia.
authors.forename: Matej
authors.initials: M
authors.lastname: Podbregar
authors.forename: Mitja
authors.initials: M
authors.lastname: Lainscak
authors.forename: Oja
authors.initials: O
authors.lastname: Prelovsek
authors.forename: Tomaz
authors.initials: T
authors.lastname: Mars
mesh_terms: D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D016207:Cytokines; C508600:IL6 protein, human; D018836:Inflammation Mediators; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha