Purpose: This study aimed to identify a novel recombinant adeno-associated virus (rAAV) capsid variant that can widely transfect the deep retina through intravitreal injection and to assess their effectiveness and safety in gene delivery.
Methods: By adopting the sequences of various cell-penetrating peptides and inserting them into the capsid modification region of AAV2, we generated several novel variants. The green fluorescent protein (GFP)-carrying variants were screened following intravitreal injection. Gene therapy experiments were conducted via intravitreal injection of rd1 mice. We validated the therapeutic effects utilizing the pupillary light reflex and visual cliff test. Assessment of retinal structure and Pde6b gene levels in rd1 mice after gene therapy further was confirmed through transcriptome sequencing to validate the gene therapy efficacy.
Results: We observed enhanced transduction and penetration efficiency of the AAV variant AAV2.CPP.21 after intravitreal injection which can target all layers of the retinas. Normal doses of AAV2.CPP.21 administered via intravitreal injection achieved effective gene therapy for retinitis pigmentosa in rd1 mice, with no increased risk of transgenic leakage in peripheral organs.
Conclusions: Our study identified another new, safe, and efficient AAV vector for gene therapy via intravitreal injection for retinal diseases. This new vector holds promise for clinical application and improvement of the efficacy of gene therapy for inherited retinal diseases.