# Targeted siRNA Delivery Against RUNX1 Via tFNA: Inhibiting Retinal Neovascularization and Restoring Vessels Through Dll4/Notch1 Signaling

## TL;DR

This study explores using tFNAs to deliver siRNA targeting RUNX1 to inhibit retinal neovascularization and restore blood vessels via the Dll4/Notch1 pathway.

## Contribution

The novel use of tFNAs for targeted siRNA delivery to inhibit RNV and restore vascular integrity through Dll4/Notch1 signaling.

## Key findings

- tFNAs-siRUNX1 inhibited endothelial cell proliferation, migration, and tube formation in vitro.
- In mouse models, tFNAs-siRUNX1 reduced neovascularization and vascular leakage.
- The treatment modulated the Dll4/Notch1 pathway and reduced endothelial cell apoptosis.

## Abstract

To assess the efficacy of tetrahedral framework nucleic acids (tFNAs) as a delivery system for small interfering RNA (siRNA) targeting RUNX1 (siRUNX1) in inhibiting retinal neovascularization (RNV) and restoring vascular integrity via the Dll4/Notch1 signaling pathway.

tFNAs and tFNAs-siRUNX1 were synthesized using annealing of single-stranded DNAs and characterized by PAGE and high-performance capillary electrophoresis. Human umbilical vein endothelial cells were treated under hypoxic conditions with tFNAs-siRUNX1, and cellular uptake was evaluated using fluorescence microscopy and flow cytometry. Angiogenesis was assessed through EdU proliferation, tube formation, and wound-healing assays. In vivo experiments used oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV) models in mice, with subsequent imaging by optical coherence tomography (OCT) and fundus fluorescence angiography. Gene and protein expression were analyzed by RT-PCR and Western blotting, focusing on the Dll4/Notch1 pathway and apoptosis markers.

tFNAs-siRUNX1 effectively inhibited endothelial cell proliferation, migration, and tube formation in vitro. In OIR and CNV models, it reduced neovascularization, nonperfusion areas, and vascular leakage. The mechanism involved modulation of the Dll4/Notch1 pathway, with decreased Dll4, Notch1, and Hes1 and increased Nts expression. tFNAs-siRUNX1 also reduced endothelial cell apoptosis via the Bcl-2/Bax pathway.

tFNAs-siRUNX1 is a promising delivery system for targeting RNV, inhibiting neovascularization, and restoring retinal vascular integrity, providing a potential therapeutic alternative to anti-VEGF treatments.