Is Human Double Minute-2 A New Marker Of Angiogenesis In Exercised Human Skeletal Muscle?

Protein expression of the E3 ubiquitin ligase Murine Double Minute-2 (Mdm2) is increased in response to exercise training in mouse skeletal muscle. By regulating endothelial cell proliferation and migration in the muscle tissue, Mdm2 is indispensable for exercise-induced angiogenesis to occur (Roudier et al., FASEB J 2012). Objective Here, we investigated in human skeletal muscle if exercise training exerts a similar effect on Human Double Minute-2 (Hdm2), the human homologue of Mdm2 protein, and if a link is present between Hdm2 and the endothelial marker Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1). Method Protein levels for Hdm2 and PECAM-1 were measured by western blot in vastus lateralis muscle biopsies from 16 young and 14 senior subjects enrolled in a 6-week training program. Results Exercise training significantly increased Hdm2 and PECAM-1 protein expression. In the young population, a significant correlation was observed between exercise-induced increases in Hdm2 and PECAM-1 proteins. Conclusion Results from our previous study in rodents translate here to human subjects and suggest that Hdm2 might represent a key regulator of exercise-induced angiogenesis in human skeletal muscle. This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).