Effect of EGF-induced HDAC6 activation on corneal epithelial wound healing.

Epidermal growth factor (EGF) stimulates migration in corneal epithelial wound healing. The purpose of this study was to investigate the effect of EGF-induced alpha-tubulin deacetylation through activating HDAC6 on migration in corneal epithelial wound healing. Human corneal epithelial (HCE) cells were cultured in DMEM/F12 medium containing 10% FBS in a 37 degrees C incubator supplied with 5% CO(2). Western blot analysis was used to determine protein expression. Activity of HDAC6 was suppressed by trichostatin A (TSA) and by siRNA specific to HDAC6. Corneal epithelial cell migration was measured by using scratch-induced directional migration assay in cultured cells and by corneal epithelial debridement using a mouse whole-eye organ culture model. The authors found EGF stimulated corneal epithelial cell migration in wound healing by enhancing HDAC6 activity, resulting in the deacetylation of alpha-tubulin. EGF stimulated HDAC6 enzymatic activity and protein translocation toward the leading edge of the cell. Inhibition of HDAC6 activity by TSA significantly suppressed EGF-induced cell migration and delayed EGF-induced wound healing in epithelially debrided mouse corneas. In the meantime, knockdown of HDAC6 mRNA with specific siRNA effectively abolished EGF-induced deacetylation of alpha-tubulin, resulting in the inhibition of cell migration. These results reveal an important mechanism that involves EGF-induced HDAC6 activation and alpha-tubulin deacetylation, subsequently affecting corneal epithelial migration in the wound-healing process.