Photoreceptor-targeted extracellular vesicles-mediated delivery of Cul7 siRNA for retinal degeneration therapy
Dong Guo, Yuntong Sun, Junqi Wu, Linchao Ding, Yiwen Jiang, Yadong Xue, Yongjun Ma, Fengtian Sun
Abstract
Rationale: Photoreceptor loss is a primary pathological feature of retinal degeneration (RD) with limited treatment strategies.RNA interference (RNAi) has emerged as a promising method of gene therapy in regenerative medicine.However, the transfer of RNAi therapeutics to photoreceptors and the deficiency of effective therapeutic targets are still major challenges in the treatment of RD.Methods: In this study, photoreceptor-derived extracellular vesicles (PEVs) conjugated with photoreceptor-binding peptide MH42 (PEVs MH42 ) were prepared using the anchoring peptide CP05.Transcriptome sequencing was applied to investigate the potential therapeutic target of RD.We then engineered PEVs MH42 with specific small-interfering RNAs (siRNAs) through electroporation and evaluated their therapeutic efficacy in N-methyl-N-nitrosourea (MNU)-induced RD mice and Pde6 rd1/rd1 mutant mice.Results: PEVs MH42 were selectively accumulated in photoreceptors after intravitreal injection.Cullin-7 (Cul7) was identified as a novel therapeutic target of RD.Taking advantage of the established PEVs MH42 , siRNAs targeting Cul7 (siCul7) were efficiently delivered to photoreceptors and consequently blocked the expression of Cul7.Moreover, suppression of Cul7 effectively protected photoreceptors to alleviate RD both in MNU-induced mouse model and Pde6 rd1/rd1 mutant mouse model.Mechanistically, PEVs MH42 loaded with siCul7 (PEVs MH42 -siCul7)-induced Cul7 downregulation was responsible for preventing Cul7-mediated glutathione peroxidase 4 (Gpx4) ubiquitination and degradation, resulting in the inhibition of photoreceptor ferroptosis.Conclusions: In summary, PEVs MH42 -siCul7 attenuate photoreceptor ferroptosis to treat RD by inhibiting Cul7-induced ubiquitination of Gpx4.Our study develops a PEVs-based platform for photoreceptor-targeted delivery and highlights the potential of PEVs MH42 -siCul7 as effective therapeutics for RD.