ELF-MF transiently increases skeletal myoblast migration: possible role of calpain system.
OBJECTIVE
Cell migration is crucial for myogenesis since it is required for the alignment and fusion of myoblast. Ca(2+) signals are involved in regulating myoblast migration and an extremely low frequency (ELF) magnetic field (MF) increases intracellular calcium levels in C2C12 myoblast. This study was aimed at investigating whether ELF-MF could affect myoblast migration. As calpains contribute to the regulation of myoblast motility, the effect of ELF-MF on μ- and m-calpain was also investigated.


METHODS
The effect of ELF-MF (1 mT; 50 Hz) on C2C12 cell motility was observed by wound-healing assay. Protein expression of calpains, calpastatin, myristoylated alanine-rich C-kinase substrate (MARCKS) and vinculin were examined by Western blot analysis. Casein zymography and immunofluorescence analysis were carried out to evaluate, respectively, activity levels of calpains and intracellular distribution of calpains, calpastatin and actin.


RESULTS
Exposure to ELF-MF resulted in a transient but significant increase of myoblast migration. This stimulatory effect was associated with a marked increase of μ- and m-calpain activity followed by the concomitant variation in their subcellular localization. No significant changes in intracellular distribution and protein levels of calpastatin were detected. Finally, a significant decrease of MARCKS expression and modifications of actin dynamics were reported.


CONCLUSIONS
This study clearly outlines an involvement of calpains in ELF-MF-mediated myoblast migration.
Departments of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, 67100 Italy. riorio@cc.univaq.it
Roberto
R
Iorio
Francesca
F
Bennato
Fabrizio
F
Mancini
Rosella Cardigno
RC
Colonna
D000818:Animals; D002154:Calpain / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D051379:Mice; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D011829:Radiation Dosage
D002154:Calpain