Serine Proteinase Inhibitor SERPINA3K Suppresses Corneal Neovascularization via Inhibiting Wnt Signaling and VEGF

Purpose: To evaluate the anti-neovascularization effects and investigate the possible mechanisms of SERPINA3K, a member of serine proteinase inhibitor family, using a specific rat model of suture-induced corneal neovascularization. Methods: A rat corneal suture model was set up and SERPINA3K was topically administered three times daily for 7 days. The clinical indications were evaluated on day 2, 5 and 7, including area of neovascularization and inflammation index. The eyeballs were collected after day 7 and the following examinations were performed: histological investigation, immunostaining, western blot and quantitative real-time polymerase chain reaction (PCR) assay. Wnt3a, a Wnt pathway ligand, was added to cultured Human Umbilical Vein Endothelial Cells (HUVEC), followed by detecting cell migration and western blot. Meanwhile, an in vitro VEGF165-stimulated HUVEC model was applied and the following measurements were conducted: cell proliferation, cell migration and tube formation. Results: SERPINA3K significantly suppressed corneal neovascularization and inhibited corneal inflammation. SERPINA3K downregulated the levels of β-catenin, non-pi-β-catenin and transcription factor 4 (TCF4), but upregulated the level of pi-β-catenin of the corneas induced by suture. SERPINA3K also decreased the gene expression and protein level of VEGF. Meanwhile, induction of Wnt3a increased the cell migration, activated the Wnt signaling and upregulated VEGF in cultured HUVEC, which were antagonized by SERPINA3K. In addition, SERPINA3K significantly inhibited VEGF165-induced cell proliferation and migration of HUVEC, SERPINA3K also specifically suppressed the VEGF165-induced tube formation of HUVEC. Conclusions: SERPINA3K has therapeutic potential for corneal neovascularization. The underlying mechanism may be through inhibiting Wnt signaling pathway and VEGF.