Aquaporin 5 promotes corneal wound healing

Aquaporins (AQPs), ordinarily regarded as water channels, have recently been shown to participate in other cellular functions such as cell-to-cell adhesion, cell migration, cell proliferation etc. The current investigation was undertaken to find out whether AQP5 water channel plays a role in corneal epithelial wound healing. Expression of AQP5 in mouse cornea and transfected Madin-Darby canine kidney (MDCK) cells was detected using immunofluorescence or EGFP tag. Cell migration and proliferation, the two major events in wound healing, were studied in vitro using cell culture scratch-wound healing model and cell proliferation assay, in vivo by conducting wound healing experiments on corneas of wild-type and AQP5 knockout mouse model and ex vivo on corneal epithelial cells isolated from wild type and AQP5 knockout mice. MDCK cells stably expressing AQP5 showed significantly higher levels of cell migration and proliferation compared to control cells. Likewise, corneal epithelial cells of wild type mouse with innate AQP5 exhibited faster wound healing than those of AQP5 knockout in vivo and under ex vivo culture conditions. In vitro, in vivo and ex vivo studies showed that presence of AQP5 improved cell migration, proliferation and wound healing. The data collected suggest that AQP5 plays a significant role in corneal epithelial wound healing.