Gene expression data from corticosteroid-treated neonatal rat cardiomyocytes

Recent studies have highlighted the role of adrenal corticosteroid signaling in cardiac physiology and pathophysiology. It is known that glucocorticoids and aldosterone are able to bind glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), and these ligand-receptor interactions are redundant. Therefore, it has been impossible to delineate how these nuclear receptors couple with corticosteroid ligands and differentially regulate gene expression for operation of their distinct functions in the heart. Here, to particularly define the role of GR, we applied ligand-based approach involving GR-specific agonist cortivazol (CVZ) and GR antagonist RU486, and performed microarray analysis using rat neonatal cardiomyocytes. We indicated that glucocorticoids appear to be a major determinant of GR-mediated gene expression when compared with aldosterone. Moreover, expression profiles of these genes highlighted numerous roles of glucocorticoids in various aspects of cardiac physiology. Keywords: comparison of the effect of steroidal ligands We analyzed gene expression changes after exposure of cells to corticosterone (COR), aldosterone (ALD), and cortivazol (CVZ) in the absence or presence of GR antagonist RU486. Since our preliminary experiments using several cell lines showed that expression of many GR target genes was induced by glucocorticoids in 3 h and to avoid secondary effects of the products of GR-regulated genes, we in the present study set the time periods of exposure to these ligands as 3 h. DNA microarray experiments were performed twice with the same protocol except for RU486 treatment.