Exosome based intraocular therapy combined with active targeting of ocular neovascularization

摘要

Abstract Intravitreal injection of anti-vascular endothelial growth factor (VEGF) agent monotherapy is the current mainstay for treating neovascular age-related macular degeneration (NVAMD). However, despite its vision saving benefit, some patients fail to respond to the treatment because of insufficient therapeutic effect and/or the socioeconomic burden of frequently required repeat injection. Therefore, the long-term goal of our studies is to develop superior or adjunctive approaches to the current anti-VEGF therapy that can provide active targeting of NVAMD, have the capacity to deliver multiple drugs, and maintain long-term efficacy. Exosomes are naturally occurring, cell- secreted, and nano-sized extracellular vesicles capable of carrying various cargos including microRNAs, proteins, and lipids for cell-to-cell communications. Based on these characteristics, exosomes have great potential to be used as novel carriers for intraocular drug delivery. Recently, we have shown that ASL-exosomes composed of Anchor, Spacer, and Arg-Gly-Asp acid (RGD) Ligand-modification actively target angiogenesis in cancer. However, studies demonstrating the utility of exosomes in intraocular drug delivery systems remains to be explored. The overall objectives of this application are to develop a novel ASL-exosome based intraocular drug delivery system for the treatment of NVAMD that actively targets ocular neovascularization (NV) and can deliver multiple drugs with sustained efficacy. The central hypothesis of the proposal is that ASL-exosomes can co- deliver Eylea and miR-24, a new intracellular target for choroidal NV, and effectively suppress NV by active targeting and sustained drug delivery with minimal immune responses. We hypothesize that localized delivery of ASL-exosomes to NV lesions using RGD-integrin ligand binding mediated active targeting will also increase intracellular uptake of ASL-exosomes by integrin receptor-mediated intracellular endocytosis. The central hypothesis will be tested by pursuing two specific aims. Aim 1 is to determine the mechanism by which ASL- exosomes actively target ocular NV and to evaluate whether RGD mediated active intracellular uptake of ASL- exosomes bypasses ocular cell tropism directed intracellular uptake of exosomes. Aim 2 is to determine sustained multi-drug delivery using ASL-exosomes and related immune response. The research proposed in this application is innovative, because the combination of an exosome-based intraocular drug delivery system with active targeting is a novel strategy that has potential to change the current treatment paradigm from passive targeting-directed monotherapy to active targeting-directed multi-drug delivery with sustained efficacy for the treatment of various retinal and choroidal vascular diseases, such as NVAMD, diabetic retinopathy and retinal vein occlusion.