Technologies for imaging the retina in animal models and patients have been significantly improved through advances in instrumentation, enabling high-resolution imaging of tissue structure. Furthermore, decades of basic and clinical research have identified a number of molecular biomarkers which may be valuable for assessing susceptibility to retinal disease, early disease, and disease progression, as well as dissecting molecular mechanisms in preclinical studies. The goal of this proposal is to build upon advances in imaging instrumentation and biomarker research in order to develop technologies for in vivo molecular imaging of the retina. The strategy is based on hairpin functionalized gold nanoparticles (hAuNP), biocompatible gold colloids engineered to enter living tissues and fluoresce upon hybridization with targeted messenger RNA (mRNA) or microRNA sequences. Recently published and preliminary studies demonstrate that hAuNP are capable of specifically targeting multiple distinct RNA sequences in mammalian cells and the retinal vasculature, without adverse effects on cell function. In this proposal, hAuNP will be utilized to validate mRNAs and microRNAs as biomarkers of choroidal neovascularization (CNV), using a mouse model of laser- induced choroidal neovascularization (LCNV).
In Aim 1, hAuNP will be used to image CNV-relevant biomarkers in primary choroidal endothelial cells and retinal pigment epithelial cells, and the biodistribution and safety profiles of hAuNP will be further tested in mouse models.
In Aims 2 and 3 of the proposal, hAuNP will be evaluated in a mouse model of LCNV in order to establish the utility of longitudinal, multiplexed RNA imaging. These studies will set the framework for molecular imaging of RNA and other molecular biomarkers in animal models, and will facilitate clinical translation of these technologies for early detection and staging of disease in patients.
Early detection of neovascularization in AMD is critical for preserving vision, since choroidal neovascularization (CNV) is a key blinding complication in AMD patients. In this proposal, molecular biomarkers of subclinical and/or early CNV will be detected using fluorescent nanoparticles. This work is clinically translational and will eventually enable the clinician to begin treatment earlier, when it can be more effective.
