Wnt5a, a New Diabetic Corneal Marker Related to Wound Healing

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Diabetes is the most widespread blinding disease in working-age adults. Up to 70% of diabetic patients suffer from corneal problems including neuropathy and epithelial keratopathy (impaired wound healing, ulcers, recurrent erosions) that impair vision and cause pain and discomfort. Diabetic keratopathy is underdiagnosed, and therapy remains symptomatic. We previously identified markers altered in human diabetic corneas and normalized their levels in human corneal organ cultures by gene and nano therapy, which also restored normal stem cell phenotype and corneal wound healing. Epigenetic changes may contribute to diabetic complications. Therefore, we examined epigenetic DNA methylation in human diabetic corneas and found a set of genes abnormally methylated vs. normal corneas. WNT5A gene, a noncanonical member of Wnt regulators of cell motility, proliferation and differentiation, was hypermethylated in diabetic corneas. Its expression was reduced in diabetic corneas and stem cell-enriched epithelial cultures. Wnt5a addition accelerated wound healing in diabetic (but not in normal cells), with stem cell marker expression increase. Inhibition of diabetes-increased miRNA-203a targeting WNT5A increased Wnt5a and wound healing in diabetic cells. miRNA-203a inhibitor and WNT5A siRNA reduced wound healing in normal cells. We will identify mechanisms of action of new diabetic marker Wnt5a, its effects on diabetic corneal cell populations, and normalize its levels in diabetic corneal cells. We hypothesize that normalization of diabetes-impaired stem cell phenotype and epithelial wound healing may be achieved by restoring normal expression of noncanonical Wnt5a by blocking its inhibiting microRNA with a novel nanoconjugate and using demethylating agents. Specific Aim 1. To identify Wnt5a receptor(s) mediating its effects on diabetic epithelial cells and corneas. Wnt5a receptors in diabetic limbal cells and corneas will be identified by imaging and functionally, by siRNAs, focusing first on ROR2. This will allow modulating their expression and signaling in diabetic cells to boost Wnt5a effects. Specific Aim 2. To examine Wnt5a effects on epithelial wound healing and limbal cell populations in human organ-cultured diabetic corneas. In these corneas, we will confirm normalizing Wnt5a effects using wound healing and stem cell marker expression. Changes in limbal epithelial differentiated and stem cell populations upon Wnt5a (or inhibitors) treatment will be examined by single cell RNA-seq vs. control normal cells. Specific Aim 3. To test the efficacy of therapies aimed at increasing Wnt5a expression using cultured diabetic cells and organ-cultured corneas. Diabetic limbal epithelial cells and corneas will be treated with nanoconjugate with miR-203a specific antagonist and/or with demethylating 5-Aza-2′-deoxycytidine (Decitabine) or Zebularine. Our aims fit well the priorities set in the NEI Vision Research: Needs, Gaps, and Opportunities. These priorities include (1) improving the transplantation of cultured corneal epithelial cells, (2) understanding of the epigenetic regulation of wound healing, and (3) developing methods to enhance the wound healing process.