Transcriptional changes induced by over-expression of miR-142-3p in C2C12 myoblasts.

Skeletal muscle has a central role in whole body metabolism with myofibers that represent its functional units. These are differentiated cells with different contraction power and metabolic traits. Faster contracting myofibers preferentially use glucose as substrate for energy production, while slower use lipids. Myofibers can plastically change phenotypic traits in response to pathophysiological stimuli. Since post-transcriptional mechanisms should administer the changes of these post-mitotic cells, we demonstrated that miR-142-3p influences myofiber fuel availability and mitochondrial morphology. In vitro and in vivo experiments demonstrate that miR-142-3p regulates lipids utilization. We used microarrays to characterize the global changes in gene expression in C2C12 myoblasts due to over-expression of miR-142-3p. C2C12 myoblasts were transfected with miR-142-3p mimic or a scrambled sequence, as control. Transfection efficiency was estimated of about 60%. Transfection experiments were independently repeated in 6 replicates for miR-142-3p mimic and 4 replicates for scrambled sequence. Results were evaluated after 72 hours of transfection.