Modulations du génome exprimé dans le muscle squelettique avec l’entraînement physique

Abstract

Aims Physical exercise leads to changes in contractile and biochemical properties. Muscle characteristics are mainly explained by the presence of several protein families, which exist as different isoforms. Each of these isoforms is encoded by specific genes. The aim of this paper is to present the current knowledge concerning alterations in muscle gene expression in response of physical exercise. In this paper, we stress the knowledge concerning the involvement of intracellular signaling pathways, which ensure the link between the molecular events related to physical exercise and changes in the transcription levels of target genes. Current knowledge Changes in contractile and metabolic properties of skeletal muscle observed during physical training are now well-known. In contrast, the molecular mechanisms at the origin of changes in gene expression remain to be extensively examined. It has been hypothesized that physical exercise leads to elementary signals that are distinctly sensed by skeletal muscle tissue. These signals will recruit specific intracellular pathways and then account for transcriptional adaptations that are seen in skeletal muscle. It has been suggested that transcriptional regulations during physical training result from the influence of many external and internal factors pooled into four categories. Neuronal factors recruit signaling pathways related to transient changes in intracellular calcium, such as calcineurin, calmodulin-dependent protein kinases and PKC pathways. Mechanical factors modulate specific transcriptional changes through mitrogen-activated protein kinase signaling pathways, especially p38 and extracellular signal-regulated kinase-1/2 pathways. Metabolic signals activate the mitochondrial biogenesis through PGC-1α or oxygen-sensitive genes through the hypoxia inducible factor complex. Hormonal signals will not be discussed in the present paper. Futur prospects Future studies are needed to estimate the role played by each of these signaling pathways to explain the phenotypic changes reported in skeletal according to the physical training characteristics. Moreover, the signaling pathways involved to explain muscle adaptation mostly interact; these interactions need to be examined during several forms of physical training.