Acute Transcriptional Effects of Dexamethasone on Mouse Adrenal Gland Transcriptome

Researchers have long known that dexamethasone causes cellular and functional changes in the adrenal gland. For example, long-term dexamethasone treatment leads to reversible adrenal cortex atrophy. In the adrenal medulla, dexamethasone treatment alters the maturation and function of the neural crest-derived chromaffin cells. Here we aim to study the acute transcriptional effect of dexamethasone on mouse adrenal gland at the transcriptome level. Our data suggested that a one-hour dexamethasone treatment had a cell type-specific effect on the adrenal transcriptome. There were 922 dexamethasone-induced genes and 853 dexamethasone-suppressed genes. GO analysis showed that the upregulated genes were primarily linked to neuronal cell function. Clustered heatmaps further showed that many genes involved in the catecholamine synthesis were upregulated by dexamethasone treatment, whereas most genes involved in the steroidogenesis pathway were downregulated. Interestingly, steroidogenic factor 1 (SF1, encoded by Nr5a1), the critical transcription factor that regulates steroidogenesis, had a >2-fold decrease under the one-hour dexamethasone treatment, suggesting a possible mechanism of the acute suppression of steroidogenic activity. Our findings indicate that the acute effects of dexamethasone stimulate catecholamine synthesis in the medulla, whereas steroidogenesis in the cortex is suppressed by dexamethasone.