A Self-Delivery siRNA for Promoting Regenerative Healing in the Eye

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Project Summary Corneal scarring and glaucoma accounts for ocular disability in millions of veterans, active military, and civilians. Injuries to the eye remain a battlefield and clinical challenge with the potential to severely reduce vision and quality of life. Ocular trauma and brain injury with resulting visual deficits are major causes of vision loss among our veterans and troops engaged in Operations Enduring Freedom and Iraqi Freedom. In addition to acute trauma, aging veterans have a significant increase in age-related glaucoma compared to the general population. The total cost, including treatment is estimated at 2.4 billion annually for the Armed Services. The link between cornea and glaucoma is that a) almost any severe eye injury because of the inflammation generated during wound healing and the drugs administered to treat the inflammation will lead to the onset of glaucoma, and b) the two scarring indications have similar biological underpinnings and thus it is a cost savings to work on both indications at the same time. We are proposing the use of a self-delivery siRNA to prevent and reverse scarring in the cornea and to prevent scarring in the sclera bleb made to reduce intraocular pressure in the eye. Our self-delivery (modified with cholesterol to gain entry into cells) siRNA modified for in vivo use is protected with a utility patent to prevent scarring in the eye and a second provisional patent for the modified self-delivery siRNA sequence and structure. Acute scarring, similar to chronic fibrosis, is characterized by immune cell infiltration and the persistence of cells termed myofibroblasts. Pathological myofibroblasts exhibit increased cell adhesion and tissue contraction through the force generated by binding to the extracellular matrix and the intracellular actin cytoskeleton via integrins (transmembrane proteins). We have discovered a key point in the healing pathway that can be therapeutically targeted to control cell apoptosis, immune infiltration, and integrin- mediated pathological myofibroblast development. Collectively, our studies in primary human corneal cells, pig corneal organ culture, and in rabbits demonstrate that wounding induces the expression of the deubiquitinase (DUB), USP10. USP10 removes ubiquitin from both p53 and αv-integrins. Knockdown of USP10 with one dose of self-delivery siRNA in vivo after corneal wounding significantly reduced apoptosis, immune infiltration, fibrotic markers, and corneal scarring, and a pilot study demonstrated regenerative healing in the glaucoma filtration bleb. Towards the goal of realizing the most effective and specific USP10-targeted therapeutic, in Aim 1, we propose to elucidate the USP10 domains that lead to scarring outcomes and the effect of USP10 binding partner, G3BP2 on USP10 DUB activity. In Aim 2, we will expand our studies on USP10 knockdown to determine if corneal inflammation and scarring can be totally prevented with a second dose of self-delivery siRNA and reversed by novel techniques to permit siRNA entry into a scar. In Aim 3, we will test if USP10 knockdown can prevent inflammation and scarring in the bleb after glaucoma surgery that is performed to relieve intraocular pressure elevation associated with glaucoma. Successful completion of these Aims will significantly improve our understanding of the central mechanisms that promote scarring, and will lead to the development of novel self-delivery siRNA approaches to preventing corneal and glaucoma-related blindness in the veteran and civilian populations.