Novel Lentiviral Vector with Regulatable Gene Expression

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DESCRIPTION (provided by applicant) Advanced Vision Therapies, Inc. (AV-T) is focused on the treatment of ocular diseases that cause blindness. The primary disease indication is wet age-related macular degeneration (AMD), with immediate spin-off applications to diabetic proliferative retinopathy and diabetic macular edema. Disease pathophysiology is characterized by abnormal neovascularization of the choroid or retina resulting in vessel leakage and hemorrhage, and ultimately to blindness. Therapies focused on inhibiting this process are showing promise in clinical trials; however, these therapeutics must be repeatedly injected directly into the eyes. A better delivery system is needed. AVT developed a state-of-the-art gene delivery system based on the bovine immunodeficiency virus (BIV), an animal virus that is not a human pathogen. AVT is combining the BIV vector system with novel, anti-angiogenic transgenes to rapidly develop a superior product for ocular application. These transgenes include T2-TrpRS, whose mechanism of action is based on inhibition of VEGF-function, and kininostatin, whose mechanism of action results in inhibition of endothelial cell function. Both of these processes are critical for the angiogenic process. Currently, AVI is utilizing vectors that direct constitutive expression of the therapeutic transgene. The incorporation of a transcription regulation system would greatly enhance the utility, safety, and efficacy of many gene therapy strategies, including the ocular therapies pursued by AVT. AVT has developed a novel, chimeric ligand-inducible transcriptional system, which has shown efficacy in reducing ocular neovascularization when tested in the context of a gutless adenoviral vector. However, this system has not been tested in a BIV vector. There are three specific aims for this pivotal project. 1) Generation and in vitro evaluation of a two BIV vector system. The gene regulation system has two components, a novel tamoxifen-inducible transcription factor, and the responsive promoter driving transgene expression. These components will be incorporated into two separate vectors and evaluated in vitro for marker gene induction. 2) Generation and in vitro evaluation of a single BIV vector that contains both system components. 3) Evaluation of inducible vector function following ocular delivery to mice. The vector of Aim 2 will be delivered to normal mice via subretinal injection, and marker gene induction will be qualitatively evaluated in live animals following tamoxifen delivery, and quantitatively assessed in retinal whole mounts.