Modulation of proliferation and differentiation of C2C12 skeletal muscle cells by fatty acids

Aims: This study was performed to elucidate whether mitogen-activated protein kinases (MAPKs) are involved in the modulation of the proliferation and differentiation of skeletal muscle cells by fatty acids. Main methods: C2C12 myoblasts were cultured in differentiation medium containing 2% horse serum for 3 days, and treated with each fatty acid. Phosphorylation levels of MAPKs were examined by immunoblot analysis. Key findings: The mono-unsaturated fatty acids (MUFAs), oleic acid (OA) and n-6 polyunsaturated fatty acids (n-6 PUFAs), linoleic acid (LA), γ-linoleic acid (GLA), and arachidonic acid (AA) increased the proliferation of C2C12 cells. On the other hand, n-3 polyunsaturated fatty acids (n-3 PUFAs) and saturated fatty acids (SFs) did not affect the proliferation of C2C12 cells. In addition, the treatment of cis-9, trans-11 conjugated linoleic acid (c9,t11 CLA) showed an increased cell proliferation. However, trans-10, cis-12 conjugated linoleic acid (t10,c12 CLA) significantly inhibited cell proliferation. Treatment of C2C12 cells with LA, OA, and c9,t11 CLA increased phosphorylation levels of ERK1/2 and JNK during proliferation. During cell differentiation, OA, LA, and c9,t11 CLA stimulated differentiation of C2C12 cells, whereas t10,c12 CLA inhibited differentiation. We also found that OA, LA, and c9, t11 CLA increased phosphorylation level of ERK1/2, but not JNK during differentiation. Significance: These results suggest that fatty acids are able to modulate the proliferation and differentiation of skeletal muscle and MAPKs may be involved in the modulation of the proliferation and differentiation of skeletal muscle cells by fatty acids.