Therapeutic effects of a novel siRNA-based anti-VEGF (siVEGF) nanoball for the treatment of choroidal neovascularization.

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries and is characterized by the development of choroidal neovascularization (CNV). Therapies for AMD have focused on suppressing angiogenic factors, such as vascular endothelial growth factor (VEGF), mainly via conventional anti-VEGF antibody agents. However, additional efforts have been made to develop effective small-interfering RNA (siRNA)-based intracellular therapeutic agents. In this study, we have manufactured a novel siRNA-based anti-VEGF nanoball (siVEGF NB). The siVEGF NB was composed of a siRNA hydrogel with a core of anti-VEGF sequence siRNA coated with branched PEI (bPEI) and hyaluronic acid (HA) in order by applying an electrical force. The novel siVEGF NBs, which were employed in a laser-induced CNV mouse model, were optimized as a retinal and choroidal delivery system through the vitreous humor to the sub-retinal space via CD44 receptor endocytosis on the inner limiting membrane, and showed therapeutic effects via pathways bypassing the TLR3-induced siRNA-class effect. The therapeutic effects of siVEGF NBs lasted for 2 weeks after intravitreal injection showing high targeting efficiency to the sub-retinal space. Thus, the newly developed siVEGF NB may have great potential for the delivery of RNAi-based therapeutics for ocular diseases, including AMD.

Anti-VEGF PolysiRNA Polyplex for the Treatment of Choroidal Neovascularization.

Choroidal neovascularization (CNV) is a major cause of severe vision loss in patients with age-related macular degeneration (AMD). Present ocular siRNA delivery technology is limited due to poor delivery through the retina to the choroid, where CNV originates. Our goal was to develop an optimized nanosized polyRNAi-based therapeutic delivery system to the subretinal space. We developed it by siRNA multimerization (polysiRNA) followed by coating with branched polyethylenimine and hyaluronic acid, and then evaluated its efficacy in vitro and in vivo. The polysiRNA polyplex showed a narrow size distribution (260.7 ± 43.27 nm) and negative charge (-4.98 ± 0.47 mV) owing to the hyaluronic acid outer layer. In vitro uptake of the polysiRNA polyplex by human ARPE cells was discovered, and the direct inhibition of VEGF mRNA translation was confirmed in B16F10 cells. The intravitreally administered polysiRNA polyplex overcame both the vitreous and retina barriers in vivo and reached the subretinal space efficiently. Intravitreal injection of the polysiRNA polyplex was not toxic to the retina in histopathology. Furthermore, intravitreal injections of the polysiRNA polyplex at both 1 and 7 days after laser photocoagulation inhibited laser-induced choroidal neovascularization, compared to that of the control (p < 0.05). These results suggest that anti-VEGF polysiRNA polyplexes show great potential in delivering multimeric RNAi-based therapeutics to treat retinal or choroidal disorders.