Abstract
Purpose :
The regulation of corneal wound healing remains elusive. Wnt signaling is known to mediate cell proliferation, differentiation, and migration. We hypothesize that Wnt signaling may regulate cornea wound healing.
Methods :
i) The very low-density lipoprotein receptor (VLDLR) and kallistatin (KS) are negative regulator of the Wnt signaling pathway. VLDLR knock out (VKO) mice and kallistatin-transgenic (KS-Tg) mice were used for experiments. The corneal epithelial layer was removed in anesthetized mice using Algerbrus II Ocular Burr. The abraded region was measured daily after topical application of 0.1% fluorescein solution. The corneal healing rates were also determined in mice following subconjunctival injection of different Wnt signaling inhibitors or activators.
ii) Primary human corneal epithelial cells (HCEC) were treated with Wnt conditioned medium (WCM) and purified KS after 100% confluence. The acellular area was measured after a straight-line scratch across the monolayer.
iii) After being treated with WCM with/without KS, HCEC numbers were evaluated by Trypan blue dye exclusion method.
Results :
VKO mice showed higher Wnt/β-catenin signaling activities while KS-Tg mice had lower Wnt signaling in the cornea compared with WT mice. Corneal with wound healing showed increased Wnt signaling activities. Cornea wound healing rate was significantly increased in VKO mice and decreased in KS-Tg mice compared with WT mice. Wnt signaling inhibitors such as adenovirus expressing the soluble VLDLR ectodomain, an LRP6-blocking antibody, and KS protein delayed corneal wound healing in mice. Activation of Wnt signaling in the cornea by adenovirus expressing a constitutively active mutant of β-catenin (Ad-S37A) in which the phosphorylation site Ser37 in β-catenin was substituted by Ala (S37A), and lithium chloride accelerated wound healing. In vitro, WCM enhanced HCEC migration and proliferation, while KS reversed this effect in a dose-dependent manner.
Conclusions :
Wnt/β-catenin signaling is activated during corneal wound healing. Wnt signal enhances cornea epithelial cell migration and proliferation and subsequently promotes corneal wound healing.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.