Corneal scarring due to trauma or injury is a major cause of blindness in our veterans and troops. It affects 1.5 million Americans each year and is the 3rd leading cause of global blindness. Despite using combat goggles, eye injuries occurred in 16% of wounded troops fighting in Afghanistan and Iraq. A lack of efficient therapies caused eye removal in 20% of injured troops and corneal transplantation in >45,000 American each year. This project focuses on developing nanotechnology-based gene therapy approaches that offer long-term relief without significant side effects, which is a novel modality to treat corneal blindness. During last funding period, we made remarkable progress to this end as evident from our publications and awards. We successfully identified a potent nanoparticle vector, delivery techniques, and targeted gene therapy approaches, and we tested the potential of anti-transforming growth factor-? (TGF?) genes to treat corneal blindness in vivo using a rabbit model. Our immediate goal is to test 4 novel hypotheses formulated into 4 specific aims: 1) test that the residence of polyethyleneimine conjugated gold nanoparticles (PEI2-GNPs) in the eye does not affect corneal keratocyte and endothelial density or fibril uniformity in the cornea in vivo, 2) test that bone morphogenic protein-7 (BMP7) delivery in the cornea via PEI2-GNP regulates corneal healing by mitigating fibrotic Smad signaling, increasing inhibitors of differentiation proteins, ad blocking corneal keratocyte differentiation to myofibroblasts, a mechanism of scar development in vivo, 3) test that 2-gene combination therapy consisting of hepatocyte growth factor (HGF) and BMP7 or soluble TGF? receptor II (sTGF?RII) and BMP7 genes is an innovative approach to achieve maximum resolution of fixed- and healing- corneal scars in vivo, and 4) test that a broad-based epigenetic knockdown of TGF?-induced profibrotic genes by a topical vorinostat (twice a day for 3 days) application on the eye is a novel method to treat corneal scarring in vivo without major side effects. Our published and ongoing studies strongly support these hypotheses. For corneal clarity and normal function in the adult human eye, 22,000-24000 keratocytes/mm3, 2400-3200 endothelial/mm2 and characteristic collagen fibril organization are necessary. Our ongoing studies suggest that PEI2-GNPs are a safe and potent vector for ocular drug delivery, sTGF?RII gene transfer inhibits TGF?, BMP7 modulates the Smad pathway, and HGF selectively induces apoptosis in corneal myofibroblasts. Our lab has novel in vivo rabbit and in vitro human corneal fibrosis models and substantial experience in performing animal studies, clinical eye imaging, nanoparticle characterization, histology, electron microscopy, western blotting and molecular biology techniques. Successful completion of the proposed research will significantly improve our understanding of the molecular mechanisms of corneal wound healing, continue/progress the development of a novel ocular delivery system and newer therapies for corneal blindness, and advance the vision research field.
Relevance to Veterans Health Clinical basic science and translational research is important and fulfills the mission of the Veterans Health Administration to achieve excellence in health research and offer state-of-the art care to American veterans. This proposal provides an impetus toward the development of novel and innovative therapies using hybrid gold nanoparticles providing long-term benefits. Existing therapies provide only short-term benefits, cause many side effects, and are often ineffective. The proposed preclinical research lays the groundwork for the much-needed development of targeted, effective and long-term non-viral gene therapy and nanomedicine approaches to treat, cure and prevent corneal blindness. Trauma, Injury and infections to the eye are known to cause corneal scarring. About 16% of our wounded troops from the Afghanistan and Iraq wars sustained eye injuries despite wearing combat eye protection. Vision loss from eye trauma is a major problem among our military and no currently available drugs cure corneal scarring without causing serious side effects.