SOCS2 inhibited mitochondria biogenesis via inhibiting p38 MAPK/ATF2 pathway in C2C12 cells

In order to investigate the mechanism of suppressor of cytokine signaling 2 (SOCS2) on mitochondrial biogenesis, RNA interference and over-expression plasmid vectors of SOCS2 were used to transfect murine skeletal muscle C2C12 cells. Results demonstrated that over-expression of SOCS2 inhibited the differentiation of C2C12 cells, and reduced the expression of MyHC, MyoD and MyoG while elevated the protein expression of MSTN. Meanwhile the expression of PGC-1 alpha, MDH, CPT-1 were significantly elevated in the RNA interference of SOCS2 group which were decreased in SOCS2 overexpression group. However, there was no change on the expression of UCP1 in both two groups. JC-1 dyeing showed overexpression of SOCS2 decreased the mitochondrial membrane potential and results of immunofluorescence, real-time PCR and western blotting indicated the increase expression of Cyt c, while interference SOCS2 had the opposite effects in C2C12 cells. Moreover, interference of SOCS2 elevated the p38 phosphorylation level then further increased the phosphorylation of ATF2, whereas overexpression of SOCS2 alleviated this phenomenon. Taken together, our observations indicated that SOCS2 could suppress myotube formation, act as an anti-regulator of mitochondria biogenesis via inhibiting p38 MAPK signal pathway.