VRC Inhibiting p38 to Prevent and Restore Corneal Scarring

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Project Summary Research Idea/Rationale: Corneal scarring (or fibrosis) from corneal puncture injury or laceration is one of the leading etiologies for blindness. Currently, none of the potential treatments for corneal fibrosis have been FDA- approved and none have been shown to reverse an existing corneal scar. Therefore, finding a therapeutic with the ability to reduce or control scarring, but that is not invasive or has minimal adverse effects, remains an unmet need. Studies from both in vivo and in vitro models have demonstrated that transforming growth factor- beta1 (TGF-beta1) is one of the key factors that drive corneal scarring after incision injury. However, TGF- beta1 is not an ideal therapeutic target for fibrotic diseases due to its importance in normal physiological processes (e.g., proliferation and migration). Objective/Hypothesis: During our preliminary in vitro studies, we found that an inhibitor for the TGF- beta/p38MAPK (p38)-signaling pathway, SB202190, almost completely blocked human corneal scar formation. This discovery led us to examine if p38 inhibitor could prevent the transformation of human corneal fibroblasts (normal active stromal cells) into myofibroblasts, a stromal cell phenotype that is involved in scarring. We found that p38 inhibitor accelerated the conversion of these myofibroblasts back to their normal phenotype. We hypothesize that the p38 inhibitor, SB202190, can be used as a local therapeutic for preventing and reversing corneal scarring. Specific AIMS: Aim 1:Safety evaluation of SB202190. AIM 2: Determine the therapeutic effect of the SB202190 to prevent corneal scar formation. AIM 3:Determine if an established corneal scar can be reversed by treatment with SB202190. Study Design: In this model, a 3mm perforating incision injury will be made in the center of the right cornea of Sprague-Dawley rats. For AIM 1, treatment will be applied immediately after wound creation and reevaluated at 24 hours to ensure SB202190 does not cause wound healing delays. Cytotoxicity will also be evaluated in human corneal fibroblasts. For AIM 2, SB202190 or control PBS will be applied locally for 1-15 days as follows: eye drops (topical) will be applied 3 times daily or subconjunctival injection once every three days. For AIM 3, the injured corneas will be allowed to heal for 14 days. Rats will be randomly grouped and treated locally as in AIM 1 for 0-8 weeks. Corneas will be examined for haze and proteins associated with scarring at 0-14 days post-treatment in AIM 2 and 0-8 weeks post-treatment in AIM 3 using the following techniques: 1) Slit lamp and OCT examination; 2) TEM and standard Hematoxylin and Eosin stain 3) Indirect- immunofluorescence and Western blot. Absence, or at least significant decrease, of haze and scar proteins will indicate that the inhibitor prevented scarring in the animal model.