VEGFA-Targeted M3-F4 Ionizable Lipid Nanoparticles Improve Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the leading causes of visual impairment and blindness worldwide. Current therapies for DR primarily focus on inhibiting vascular endothelial growth factor A (VEGFA); however, their efficacy remains limited due to drug resistance and the requirement for repeated intravitreal injections. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome-editing technology enables specific targeting and knockout of the VEGFA gene, offering a novel therapeutic approach for DR. In this study, we synthesized a novel ionizable lipid, M3, and assembled the optimal-performing M3-F4 into lipid nanoparticles (M3-F4 LNP) for codelivery of VEGFA-targeting Cas9 mRNA (mCas9) and single guide RNA (sgRNA). The optimized formulation, composed of M3:cholesterol:DSPC:DMG-PEG at a molar ratio of 45:42.5:10:2.5, exhibited a particle size below 100 nm, a PDI below 0.2, and an encapsulation efficiency above 80%. Sanger sequencing-based indel analysis confirmed VEGFA editing in HRMECs, with sgRNA1 achieving an indel frequency of approximately 28.7%. In high glucose-induced human retinal microvascular endothelial cells (HRMECs), the mCas9/sgVEGFA@M3-F4 LNP reduced cell proliferation, migration, invasion, and tube formation, while restoring endothelial barrier integrity and exerting anti-inflammatory effects. A single intravitreal injection of mCas9/sgVEGFA@M3-F4 LNP effectively inhibited pathological neovascularization and retinal leakage in both oxygen-induced retinopathy mice and streptozotocin-induced diabetic mice in vivo. Furthermore, it markedly attenuated VEGFA-induced inflammation while maintaining excellent biocompatibility. This study demonstrates M3-F4 LNP as a promising method for efficient CRISPR/Cas9 delivery and provides robust support for gene therapy strategies in DR treatment.