Electric Pulse Stimulation of Cultured Murine Muscle Cells Reproduces Gene Expression Changes of Trained Mouse Muscle

Abstract

Adequate levels of physical activity are at the center of a healthy lifestyle. However, the molecular mechanisms that mediate the beneficial effects of exercise remain enigmatic. This gap in knowledge is caused by the lack of an amenable experimental model system. Therefore, we optimized electric pulse stimulation of muscle cells to closely recapitulate the plastic changes in gene expression observed in a trained skeletal muscle. The exact experimental conditions were established using the peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) as a marker for an endurance-trained muscle fiber. We subsequently compared the changes in the relative expression of metabolic and myofibrillar genes in the muscle cell system with those observed in mouse muscle in vivo following either an acute or repeated bouts of treadmill exercise. Importantly, in electrically stimulated C2C12 mouse muscle cells, the qualitative transcriptional adaptations were almost identical to those in trained muscle, but differ from the acute effects of exercise on muscle gene expression. In addition, significant alterations in the expression of myofibrillar proteins indicate that this stimulation could be used to modulate the fiber-type of muscle cells in culture. Our data thus describe an experimental cell culture model for the study of at least some of the transcriptional aspects of skeletal muscle adaptation to physical activity. This system will be useful for the study of the molecular mechanisms that regulate exercise adaptation in muscle.

Are cultured human myotubes far from home?

“…In animal studies, elevation in PGC-1α is associated with fiber-type switch from glycolytic, fast-twitch type 2B/2X to oxidative, slow-twitch type 2A and 1 muscle fibers (Handschin, et al, 2007, Lin, et al, 2002. Expression of PGC-1α was also increased in primary rat skeletal muscle cells after electric stimulation for 90 min a day for 5 days (Silveira, et al, 2006), as well as in C2C12 cells stimulated for 90 min a day for 4 days or after CLF for 24 h (Burch, et al, 2010). In this latter study, expression of several genes involved in oxidative phosphorylation, glucose and fatty acid metabolism increased concomitantly, although not followed by a clear fiber type switch since both MyHC-β and MyHC-2X increased (Burch, et al, 2010).…”

“…Expression of PGC-1α was also increased in primary rat skeletal muscle cells after electric stimulation for 90 min a day for 5 days (Silveira, et al, 2006), as well as in C2C12 cells stimulated for 90 min a day for 4 days or after CLF for 24 h (Burch, et al, 2010). In this latter study, expression of several genes involved in oxidative phosphorylation, glucose and fatty acid metabolism increased concomitantly, although not followed by a clear fiber type switch since both MyHC-β and MyHC-2X increased (Burch, et al, 2010). All these studies indicate that oxidative capacity can be improved by electrical pulse stimulation (exercise mimetic) of the myotubes.…”

Proteomic identification of secreted proteins from human skeletal muscle cells and expression in response to strength training

“…Thus, we consider our cultured skeletal muscle cells to be a model of resting, noncontracting muscle cells. We have recently started to use electrical pulse stimulation to induce contraction of cultured myotubes resembling some of the in vivo effects of exercise (6), which might influence secretion of myokines (36). Our future studies will show how electrical pulse stimulation in vitro will influence myokine synthesis and secretion.…”

Characterization of contraction-induced IL-6 up-regulation using contractile C2C12 myotubes

“…Recently, we established an advanced in vitro muscle contraction model using cultured myotubes displaying vigorous EPSevoked contractile activity [17,18,21]. This model has increasingly been utilized by other researchers for investigating molecular mechanisms underlying various biological responses induced by actual contractile activity of muscle cells [24][25][26][27].…”