Role of potassium channel Kir4.1(KCNJ10) in the wound healing of human corneal epithelial cells
The cornea, which is key to maintaining our normal vision by refracting light onto the lens and retina, as well as serving as a physical barrier to protect our eyes from the environment, contains epithelium tissue with one of the highest capacities for renewal and wound healing in the body. Although many studies have looked at the process of wound healing in corneal epithelium, most of them have focused on the various ligand-receptor growth factor signaling pathways, and few studies have been done to study the signaling and regulations of wound healing that are initiated intracellularly, or those associated with electrical currents and channel activity. This study, therefore, aims to look at the hypotheses that injury to the corneal epithelium leads to the downregulation of a type of potassium transport channels named Kir4.1/KCNJ10, and that the inhibition of KCNJ10 is associated with intracellular microRNA-205 (miR-205), which is upregulated during injury and healing. Together, the modulations in the level of KCNJ10 and microRNA-205 contribute to change in the environment around the wound and promote the cellular processes that allow for efficient corneal healing. To investigate the role of potassium channels and microRNAs in the cornea epithelium, an in-vitro model of endogenous wound healing was employed with human corneal epithelium cells (HCECs) serving as the primary model of study. Physiological injury was simulated using a scratch-wound model. The protein expressions for KCNJ10 and microRNA-205 were measured through various time points from both control and injured HCECs. The effect of two RNAi modulators of microRNA-205, a mimic and antagonist, and of KCNJ10 blockers were also tested for effects on the rate and efficiency of HCEC wound healing. Results indicated that the expression of miR-205 increased in scratch-injured HCECs and that the expression of KCNJ10 decreased in wounded and healing HCECs. It was also shown that increasing KCNJ10 and decreasing miR-205 both lead to delayed healing, but that blocking KCNJ10 could partially abolished the effect of delayed healing associated with decreasing miR-205 and restored the healing process. It was also shown that the 3'UTR of KCNJ10 contains potential target sites for miR-205 binding and action. The results indicate that that KCNJ10 expression is negatively associated with corneal wound healing, and that miR-205 is upregulated upon injury in wounded corneal epithelium to inhibit KCNJ10 and allow for the processes of wound healing to take place.
Thesis (M.A.)--Boston University