Self-Assembly ECO-Plasmid DNA Nanoparticles Facilitate Robust Gene Expression Comparable to AAV2 Vector

Abstract

Purpose : Gene replacement therapy (GRT) has received increasing attention due to the success of adenoassociated virus (AAV)-based GRT for Leber’s congenital amaurosis (LCA2). However, AAVs have limited loading capacity of 4.7 kB, restricting their applications in therapies that require delivery of large genes such as Stargardt’s disease (STGD). Here, we developed a non-viral GRT based on a platform of pH-sensitive multifunctional lipid ECO with unlimited cargo capacity and compared the transfection efficiency with AAV2 using a GFP reporter gene.

Methods : Subretinal treatments were performed using retinal pigment epithelium (RPE) targeted ECO/pCMV-GFP nanoparticles and AAV2-CMV-GFP vectors with the same doses to BALB/c mice. GFP expression was examined 14 days after injection using a scanning laser ophthalmoscopy (SLO) featuring a fluorescent mode with an argon wavelengths of 488/514 nm.

Results : Subretinal delivery of both the targeted ECO/pCMV-GFP nanoparticles and AAV2-CMV-GFP vectors induced significant GFP expression comparing to untreated control (Figure 1). Both the nanoparticles and AAV2 demonstrated GFP expression across the examined retinal area. Targeted ECO-based nanoparticles demonstrated at least same level or better GFP expression than AAV2.

Conclusions : In conclusion, the targeted ECO/pCMV-GFP nanoparticles demonstrated well distributed GFP expression in BALB/c mice 14 days after treatments, comparable to the AAV2-CMV-GFP vector. The self-assembly ECO-pDNA nanoparticles have no cargo size limitation and can be a promising non-viral GRT for a broad range of monogenic retinal disorders.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1. Comparison of in vivo gene expression efficiency of ECO and AAV2 demonstrated by SLO fluorescent imaging of the treated retina 14 days after subretinal injection. White dots indicated GFP expression in the retinal tissue.