A Bifunctional Peptide with Penetration Ability for Treating Retinal Angiogenesis via Eye Drops

Numerous diseases, such as diabetic retinopathy and age-related macular degeneration, can lead to retinal neovascularization, which can seriously impair the visual function and potentially result in blindness. The presence of the blood–retina barrier makes it challenging for ocularly administered drugs to penetrate physiological barriers and reach the ocular posterior segments, including the retina and choroid. Herein, we developed an innovative bifunctional peptide, Tat-C-RP7, which exhibits excellent penetration capabilities and antiangiogenic properties aimed at treating retinal neovascularization diseases. RP7 is an NRP-1 targeting peptide that blocks vascular endothelial growth factor receptor-2 (VEGFR-2) signaling and inhibits angiogenesis, while Tat facilitates the delivery of various cargoes across biological barriers, such as the blood–retina barrier. By combining these attributes, Tat-C-RP7 is anticipated to traverse ocular barriers via ocular topical administration and exert its antiangiogenic effects in the ocular posterior segment. Experimental results demonstrated that Tat-C-RP7 significantly inhibited the proliferation and migration of rat retinal microvascular endothelial cells and effectively reduced tubule formation in vitro. Its antiangiogenic activity was confirmed in zebrafish. The outstanding penetrative capabilities of FITC-labeled Tat-C-RP7 have been validated through cell uptake assays, in vitro cell barrier models, ex-vivo ocular tissues, and in vivo studies. Besides, the half-life of Tat-C-RP7 was longer than that of RP7. In an oxygen-induced retinopathy model, Tat-C-RP7 was shown to reduce the area of angiogenesis following ocular administration. Additionally, it produced no irritating effects on the eyes of rabbits. Overall, Tat-C-RP7 demonstrates excellent ocular penetrability and antiangiogenic effects and represents a promising therapeutic option for treating retinal neovascularization diseases.