Dexamethasone increases differentiation capacity in C2C12 cells and its effects on Cdk1 and ERK1 expression /

Abstract

Glucocorticoids are steroid hormones produced in the adrenal cortex that affect a vast array of cellular functions, especially the proliferation and differentiation capacity of stem cells. Synthetic glucocorticoids have been used in the treatment of Duchenne's muscular dystrophy. These drugs affect the expression of approximately one percent of all genes and how they work at the cellular level is not well understood. This study looks at how the glucocorticoid dexamethasone (DEX) affects differentiation capacity and expression of the proteins cdkl and ERKI in mouse skeletal muscle cells. D~X was added to cultured cells upon inducing differentiation and morphological changes were used to determine developmental state. Expression levels of the proteins cdkl and ERKI were determined by Western blot and immunoblot analysis. Based on results from other studies it was expected that DEX would decrease differentiation capacity. However, the results of this study showed that DEX actually increased differentiation rate and stem cell recruitment when added at the time differentiation was induced. The cell cycle protein Cdkl was developmentally regulated as anticipated, but the MAP kinase ERKI was not affected by differentiation. Neither the expression of cdkl nor ERKI in myotubes was affected by the presence of DEX.