Delay of Corneal Epithelial Wound Healing by Stress-Induced Activation of Plk3

Abstract

Purpose:: The purpose of the study is to investigate the role of Polo-like kinase 3 (Plk3) in environmental stress-induced delay of corneal epithelial wound healing.

Methods:: Human corneal epithelial (HCE) cells and mouse corneas were cultured in DMEM/F12 medium containing 10% FBS and 5 µg/ml insulin at 37°C, 5% CO₂. UV and hypoxia experiment was performed by exposure of cells to UV-C (42 µJ/cm²) and by placing culture dishes into 36 to 38°C incubator supplemented with 1% O₂, 5% CO₂ and 94% N₂ for 1 to 4 h, or treat with CoCl_2, respectively. Corneal epithelial wound healing was evaluated by using Scratch-induced Directional Migration Assay and by Whole-eye Organ Culture Model using an Algerbrush corneal rust ring remover. Wound healing rates were analyzed and statistical significance was determined by Student t-test (p<0.05). Plk3 expression levels were determined by immunostaining experiments.

Results:: 1) UV irradiation and hypoxia stress resulted in delays of corneal epithelial wound healing. 2)CoCl₂ was used to verify the effect of hypoxia on the wound healing. 3) The effect of hypoxia on delay of corneal epithelial wound healing was temperature dependent process. 4) UV and hypoxia stresses markedly induced increases in Plk3 activity. 5) Manipulation of Plk3 activity in corneal epithelial cells significantly affected stress-induced alteration of cell viability in wound healing.

Conclusions:: Our results provided for the first time that Plk3 plays an important role in environmental stress-induced delay of corneal epithelial wound healing.

Keywords: cornea: epithelium • hypoxia • wound healing