Receptor‐targeted liposome‐peptide‐si RNA nanoparticles represent a novel and efficient si RNA delivery system to prevent conjunctival fibrosis

Purpose Glaucoma is the leading cause of irreversible blindness worldwide and fibrosis is the main cause of failure of glaucoma surgery. We have previously described how the Myocardin‐related transcription factor/Serum response factor ( MRTF / SRF ) pathway is intricately linked to all the key pathways in ocular fibrosis. Our aim was to develop a novel liposome‐peptide‐si RNA ( LYR ) nanoparticle as an efficient delivery system for MRTF si RNA in conjunctival fibrosis. Methods The LYR nanoparticles were characterised with regard to particle size and zeta potential. Real‐time qPCR and western blotting were used to compare the silencing efficiency in human Tenon's fibroblasts using different MRTF si RNA concentrations, targeting peptides, and liposomes. The cytotoxicity of the LYR nanoparticles was assessed using the MTT cell assay. Three‐dimensional fibroblast‐populated collagen matrices were also used as a functional assay to measure contraction in vitro. Results All LYR nanoparticles were strongly cationic with sizes around 100 nm and PDI s < 0.4. The LYR nanoparticles efficiently silenced the MRTF gene by 76% and 84% using 50 nM and 100 nM si RNA respectively. The MRTF gene was also efficiently silenced by 76% and 75% using the targeting peptides Y and ME 27 respectively. The MRTF protein expression was significantly decreased by the LYR nanoparticles. The non‐ PEG ylated liposome formulations showed higher silencing efficiency than the cationic PEG ylated formulations. The MRTF nanoparticles were also not cytotoxic at 50 nM si RNA concentration and prevented matrix contraction after a single transfection treatment. Conclusions This is the first study to show that receptor‐targeted liposome‐peptide‐si RNA nanoparticles represent an efficient and safe si RNA delivery system that could be used to prevent fibrosis after glaucoma surgery.