Monounsaturated fatty acids are required for membrane translocation of protein kinase C-theta induced by lipid overload in skeletal muscle.

AbstractProtein kinase C (PKC) activation induced by diacylglycerols (DAGs) is one of the sequels of the dysregulation of intramuscular lipid metabolism and is thought to play an important role in the development of insulin resistance (IR). We tested the hypothesis that DAGs with different acyl chains have different biological effects and that DAG species enriched in monounsaturated fatty acids (MUFA) act as better activators of PKC. The experiments were performed in vitro on C2C12 myotubes treated with palmitate (16:0), stearate (18:0) or oleate (18:1) and in vivo on the skeletal muscles of rats fed high-fat (HF), high-tristearin (TS) or high-triolein (TO) diets. To define the importance of endogenously synthesized MUFA on DAG-induced PKCθ activation, we performed experiments on stearoyl-CoA desaturase 1 knockout mice (SCD1-/-) as well. The results show that the content of total DAGs and the levels of saturated DAG species are significantly increased in both insulin-resistant (16:0, HF and TO) and highly...