Fig. 5

Positive role of JNK/MAPK signaling pathway in regulating myogenic differentiation. a Immunofluorescent microscopy analysis of the morphological changes and expression of p-c-Jun and myogenesis marker Myosin in myogenic precursors before and after differentiation. Scale bars, 100 μm. b The expression of myogenic marker MyoG, JNK/MAPK signaling key factors (JNK and c-Jun), and their phosphorylated forms were detected by western blotting before and after differentiation. c Relative expression level in b was calculated. GAPDH was used as the internal control. 0 h represented myogenic precursors in growth medium, and 12, 24, and 48 h represented myogenic precursors switched into differentiation medium for 12, 24, and 48 h, respectively. d Representative immunofluorescence images at 48 h after myogenic precursors treated with JNK-specific inhibitor SP600125 or DMSO in differentiation medium. DMSO was used as negative control (Ct). Scale bars, 100 μm. e, f Expression levels of MyoG, JNK/MAPK signaling key factors (JNK and c-Jun), and their phosphorylated forms (p-JNK and p-c-Jun) were detected by western blotting at 24 and 48 h after cells treated with SP600125 or DMSO in differentiation medium. g Relative expression level in e and f was calculated. GAPDH was used as the internal control. Data were presented as means ± SEM (n = 3). The statistical significance of difference between two means was calculated using t test, ^*P < 0.05, ^**P < 0.01