Injury and infection to the eye cause corneal scarring and affect over 1.5 million Americans each year. Despite the use of combat eye protection, eye injuries occurred in 16% of our wounded troops in Afghanistan and Iraq. Current therapies for corneal scarring or angiogenesis provide only short-term relief, cause serious side effects and are often ineffective. Over fifty thousand corneal transplantations in Americans each year and removal of eyes in 20% of the U.S. troops injured in recent wars highlight the incompetence of current therapy. The cornea is an ideal organ for gene therapy because of its accessibility and immune-privilege status. Recently we defined tissue-targeted GNPs or AAV5 vector gene therapy approaches for the normal and diseased rabbit eye, and showed that therapeutic genes can be delivered into target corneal cells efficiently to treat corneal scarring and angiogenesis. Our recent studies suggest that gold nanoparticles (GNPs) are safe for the cornea and thus can be used to deliver genes in the cornea in vivo. Our central hypothesis is that tissue-selective therapeutic gene delivery in the cornea can cure corneal disorders without causing significant side effects. This research project will test the hypotheses that GNPs stabilized in gum arabic or polyethyleneimine are nontoxic, non-immunogenic and efficient vehicles for transporting therapeutic genes into keratocytes of the rabbit cornea in vivo, can provide safe and novel nanotechnology-based nonviral gene therapy modalities to treat corneal diseases, and targeted delivery genes disabling transforming growth factor-2 (TGF2) function will impede corneal scarring in vivo. TGF2 gene has been shown to cause scarring in the cornea in vivo by promoting keratocyte transformation to myofibroblasts. We will define conditions for delivering therapeutic genes into rabbit keratocytes in vivo using GNPs stabilized in gum arabic or polyethyleneimine (Aim 1), test the efficacy of soluble type II TGF2 receptor (Aim 2) and bone morphogenic protein 7 (Aim 3) genes to control corneal scarring by delivering selected genes into rabbit keratocytes in vivo with GNPs or AAV5 vector. Our preliminary studies show that tested GNPs and AAV5 vectors are highly efficient in introducing genes selectively into rabbit keratocyte in vivo. Using rabbit corneal scarring model, tissue-targeted gene therapy approaches (recently optimized in our laboratory), bio-microscopy, immunocytochemistry, cellular and molecular assays testing of these aims will be accomplished. Successful completion of proposed research has the potential to extend an efficient new method to treat corneal scarring as well as other prevalent corneal diseases. Our studies on GNPs will substantially advance the research efforts in the field of ocular nanomedicine.
Project Narrative: Relevance to Veterans Health Clinically-oriented basic science research is important and fulfills the objective of the Veterans Health Administration objective to achieve excellence in health care for American veterans. This proposal provides an impetus toward the development of tissue-selective gene therapy methods using gold nanoparticles to treat corneal scarring which provide long-term benefits. Existing therapies provide only short-term benefits and are often ineffective. The proposed preclinical research lays the groundwork for the much-needed development of targeted, effective and long-term therapies to cure corneal scarring. Injury and infections to eye is known to cause corneal scarring. About 16% of our wounded troops in 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 drugs are currently available to cure corneal scarring without causing serious side effects.