Glucocorticoid Receptor Signaling is Critical for Mouse Corneal Development, Inhibition of Inflammatory Response and Neovascularization of the Cornea

Synthetic glucocorticoids are widely prescribed in the treatment of ocular infections and disorders. The actions of glucocorticoids are mediated by the glucocorticoid receptor (GR); however, the molecular and physiological functions of GR signaling in the cornea are poorly understood. In this study, we show that treatment of mice with glucocorticoid eye drops led to a profound regulation of the corneal transcriptome. To determine the global transcriptional profile of GR activity in the cornea, we treated adult wild-type male mice with dexamethasone (a synthetic glucocorticoid) eye drops or vehicle eye drops for 6 hours and then performed RNA sequencing on RNA extracted from whole corneas. All the animals used for this study were adrenalectomized to remove endogenous glucocorticoids. These data demonstrate that a short exposure of glucocorticoids to the cornea results in major changes in the gene expression landscape. Overall design: Male wild-type C57BL/6J mice that were 8 weeks old were adrenalectomized (ADX) to remove endogenous glucocorticoids. Approximately 4 weeks after the surgery, mice were treated with dexamethasone eye drops or vehicle eye drops for 6 hours. Mice were euthanized, eyes removed, and total RNA was isolated from the whole cornea. Each experimental group had 4 replicates, where each replicate had 4-6 corneas pooled into one sample. Indexed samples were sequenced using the 75bp pair-end protocol using the Illumina NextSeq500 sequencer as per the manufacturer's protocol. Reads greater than 40 million reads per sample were aligned to the reference genome UCSC mm9.