INHIBITION OF RPE CELL-MEDIATED MATRIX ADHESION AND COLLAGEN GEL CONTRACTION BY CROVIDISIN, A COLLAGEN-BINDING SNAKE-VENOM PROTEIN

Purpose. Cell-mediated collagen gel contraction plays an important rol e in the pathogenesis of proliferative vitreoretinopathy (PVR). Anti-a dhesion therapy has been suggested as a promising strategy in the trea tment of PVR. Crovidisin, a snake venom protein isolated from Crotalus viridis, has been shown to bind selectively to collagen and to inhibi t collagen-induced platelet aggregation. In the present study, the eff ectiveness of crovidisin in inhibiting the attachment of retinal pigme nt epithelial (RPE) cells to collagen, and RPE cell-mediated collagen gel contraction, was evaluated. Methods. Fluorescein isothiocyanate (F ITC)-conjugated crovidisin was prepared and used to evaluate its bindi ng affinity for collagen type I, fibronectin, vitronectin, and laminin . The inhibitory effect of crovidisin on RPE cell-mediated extracellul ar matrix attachment and collagen gel contraction was evaluated by cel l adhesion and type I collagen gel contraction assays. The cytotoxic e ffect of crovidisin was examined with a cell proliferation assay, usin g the Alamar blue method. Flavoridin, an Arg-Gly-Asp-containing peptid e from viper venom, was used for comparison. Results. FITC-coonuugated crovidisin bound selectively to collagen type I with high affinity. I t did not bind to other matrix proteins, including fibronectin, vitron ectin and laminin, nor to RPE cells. Crovidisin inhibited RPE cell att achment to type I collagen in a dose-dependent manner. This inhibitory effect was enhanced by the presence of flavoridin. Crovidisin also do se-dependently inhibited RPE cell-mediated type I collagen gel contrac tion. Crovidisin was non-toxic to RPE cells. Conclusions. Crovidisin, a snake venom-derived collagen-binding protein, possessing an inhibito ry activity on RPE cell-collagen interaction and RPE cell-mediated col lagen gel contraction, may be a useful tool for studying cell-collagen inter-action, and a potential anti-adhesion therapeutic agent for ocu lar disorders in which cell-collagen interaction is involved, such as PVR.