17β-Estradiol Protects Skeletal Myoblasts From Apoptosis Through p53, Bcl-2, and FoxO Families

Abstract

17β-Estradiol (E2) protects several nonreproductive tissues from apoptosis, including skeletal muscle. Previously, we showed that E2 at physiological concentrations prevented apoptosis induced by H2O2 in skeletal myoblasts, reverting PKCδ, JNK, and p66Shc activation and exerting a beneficial action over mitochondria. Since genomic actions underlying the regulation of nuclear gene transcription are a common property of this steroid, the present work characterizes the transcriptional activity modulated by E2 to exert its antiapoptotic effect. We report that E2 protects skeletal myoblasts against apoptosis induced by H2O2 modulating p53 and FoxO transcription factors and then their target genes Bcl-2, Bim, Puma, PERP, and MDM2, without affecting Noxa gene. The results presented in this work support the notion that the transcription factors FoxO and p53 coordinate apoptosis in C2C12 cells, and deepens our knowledge about a putative molecular mechanism by which E2 exerts beneficial effects against oxidative stress in skeletal myoblasts.