Tetrahedral DNA nano-PROTACs enable enhanced ocular penetration and efficient nucleolin degradation for choroidal neovascularization therapy

Despite the paradigm shift brought about by anti-VEGF therapy against neovascular age-related macular degeneration, significant challenges persist, including the risk of intraocular infection and retinal structural damage caused by frequent intravitreal injections, suboptimal long-term outcomes in some patients, as well as economic and psychological burdens. Attempts to identify novel therapeutic targets with more compliant drug delivery strategies are warranted. In this study, we identify that nucleolin (NCL) is upregulated in choroidal neovascularization lesions and mobilized to the endothelial cell surface upon VEGF stimulation. Inspired by this localization change and the critical role of NCL in angiogenesis, we developed an integrated delivery and degradation platform, named dNCL@tFNAs, which leverages tetrahedral framework nucleic acids (tFNAs) to decorate an aptamer-based proteolysis-targeting chimera for NCL through a simple Watson-Crick pairing. dNCL@tFNAs exhibits notable stability, improved ocular penetration and degradation efficiency. Mechanistic study reveals that membrane-associated NCL promotes the uptake of dNCL@tFNAs into the endothelial cells, followed by engaging the cytosolic PROTAC machinery to degrade intracellular NCL via the ubiquitin-proteasome pathway. In vivo study demonstrates that dNCL@tFNAs enables administration via a minimally invasive subconjunctival injection to suppress choroidal neovascularization with a favorable safety profile. Collectively, our work establishes a programmable delivery and degradation modality for the treatment of choroidal neovascularization and other ocular neovascular diseases.