Creatine enhances differentiation of myogenic C2C12 cells by activating both p38 and Akt/PKB pathways.
In myogenic C(2)C(12) cells, 5 mM creatine increased the incorporation of labeled [(35)S]methionine into sarcoplasmic (+20%, P < 0.05) and myofibrillar proteins (+50%, P < 0.01). Creatine also promoted the fusion of myoblasts assessed by an increased number of nuclei incorporated within myotubes (+40%, P < 0.001). Expression of myosin heavy chain type II (+1,300%, P < 0.001), troponin T (+65%, P < 0.01), and titin (+40%, P < 0.05) was enhanced by creatine. Mannitol, taurine, and beta-alanine did not mimic the effect of creatine, ruling out an osmolarity-dependent mechanism. The addition of rapamycin, the inhibitor of mammalian target of rapamycin/70-kDa ribosomal S6 protein kinase (mTOR/p70(s6k)) pathway, and SB 202190, the inhibitor of p38, completely blocked differentiation in control cells, and creatine did not reverse this inhibition, suggesting that the mTOR/p70(s6k) and p38 pathways could be potentially involved in the effect induced by creatine on differentiation. Creatine upregulated phosphorylation of protein kinase B (Akt/PKB; +60%, P < 0.001), glycogen synthase kinase-3 (+70%, P < 0.001), and p70(s6k) (+50%, P < 0.001). Creatine also affected the phosphorylation state of p38 (-50% at 24 h and +70% at 96 h, P < 0.05) as well as the nuclear content of its downstream targets myocyte enhancer factor-2 (-55% at 48 h and +170% at 96 h, P < 0.05) and MyoD (+60%, P < 0.01). In conclusion, this study points out the involvement of the p38 and the Akt/PKB-p70(s6k) pathways in the enhanced differentiation induced by creatine in C(2)C(12) cells.
Deldicque
Louise
L
Department of Physical Education and Rehabilitation, Université Catholique de Louvain, Place Pierre de Coubertin 1, 1348, Louvain-la-Neuve, Belgium.
Theisen
Daniel
D
Bertrand
Luc
L
Hespel
Peter
P
Hue
Louis
L
Francaux
Marc
M
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D064211:Connectin; D003401:Creatine / Q000378:metabolism / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D064326:MEF2 Transcription Factors; D051379:Mice; D008954:Models, Biological; D024510:Muscle Development / Q000187:drug effects / Q000502:physiology; D009124:Muscle Proteins / Q000378:metabolism; D017570:MyoD Protein / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018006:Myogenic Regulatory Factors / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011034:Podophyllotoxin / Q000031:analogs & derivatives / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction; D020107:Troponin T / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D064211:Connectin; D007093:Imidazoles; D064326:MEF2 Transcription Factors; D009124:Muscle Proteins; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D018006:Myogenic Regulatory Factors; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D020107:Troponin T; D010725:Phosphocreatine; C415032:picropodophyllin; D011494:Protein Kinases; D017526:Receptor, IGF Type 1; D051057:Proto-Oncogene Proteins c-akt; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D038362:Glycogen Synthase Kinase 3; D018995:Myosin Heavy Chains; D011034:Podophyllotoxin; D003401:Creatine; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole