Characterization and Role of KCa3.1 Ion Channel in Corneal Wound Healing and Fibrosis

Abstract

Purpose : We sought to study the role of intermediate-conductance Ca2+-activated K+ channels (KCa3.1) corneal wound healing and fibrosis management using transgenic KCa3.1 knockout mouse in vivo and human cornea in vitro.

Methods : Donor human corneas, human corneal epithelial, fibroblast and endothelial cells, and blackC57 wild type and KCa3.1knockout mice were used to characterize expression of KCa3.1 in the cornea. Quantitative RT-PCR, Western blotting, scratch assay, and immunofluorescence, and TRAM-34 (selective KCa3.1 inhibitor) were used to study the role of KCa3.1 in corneal wound healing and fibrosis treatment. Corneal fibrosis in human cornea in vitro was produced by TGFb1 and in vivo in mouse cornea by alkali-injury. Cytotoxicity of TRAM-34 was tested with trypan blue assay.

Results : Substantial KCa3.1 gene and protein levels were detected in all three major layers of the human cornea. The corneas of KCa3.1 deficient mice demonstrated significantly reduced expression of profibrotic genes, collagen-I, collagen IV and alpha smooth muscle actin (αSMA), compared to wild type mice. The eyes of age- and sex-matched KCa3.1^-/- mice showed reduced corneal opacification in live animals and myofibroblast cells in corneal tissues in vivo at 3, 7 and 14 days after alkali-injury compared to the KCa3.1^-/- mice. A selective KCa3.1 inhibitor, TRAM-34, significantly inhibited TGFβ1-induced migration (P <0.01) and transdifferentiation of HCF to myofibroblasts (P <0.001). Additional, studies characterizing role of KCa3.1 in corneal fibrosis are underway.

Conclusions : KCa3.1 modulates corneal wound healing and may potentially offer an innovative approach for controlling corneal fibrosis in vivo.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.