Reactive oxygen species decrease cAMP response element binding protein expression in cardiomyocytes via a protein kinase D1-dependent mechanism that does not require Ser133 phosphorylation

Abstract

Reactive oxygen species (ROS) exert pleiotropic effects on a wide array of signaling proteins that regulate cellular growth and apoptosis. This study shows that long-term treatment with a low concentration of H2O2 leads to the activation of signaling pathways involving extracellular signal-regulated kinase, ribosomal protein S6 kinase, and protein kinase D (PKD) that increase cAMP binding response element protein (CREB) phosphorylation at Ser133 in cardiomyocytes. Although CREBSer133 phosphorylation typically mediates cAMP-dependent increases in CREB target gene expression, the H2O2-dependent increase in CREB-Ser 133 phosphorylation is accompanied by a decrease in CREB protein abundance and no change in Creluciferase reporter activity. Mutagenesis studies indicate that H2O2 decreases CREB protein abundance via a mechanism that does not require CREB-Ser133 phosphorylation. Rather, the H2O2-dependent decrease in CREB protein is prevented by the proteasome inhibitor lactacystin, by inhibitors of mitogenactivated protein kinase kinase or protein kinase C activity, or by adenoviral-mediated delivery of a small interfering RNA that decreases PKD1 expression. A PKD1-dependent mechanism that links oxidative stress to decreased CREB protein abundance is predicted to contribute to the pathogenesis of heart failure by influencing cardiac growth and apoptosis responses. Copyright © 2009 The American Society for Pharmacology and Experimental Therapeutics.