Ocular Delivery of pRNA Nanoparticles: Distribution and Clearance After Subconjunctival Injection

Abstract

Purpose RNA nanoparticles derived from the three-way junction (3WJ) of the pRNA of bacteriophage phi29 DNA packaging motor were previously found to be thermodynamically stable. As the nanoparticles could have potential in ocular drug delivery, the objectives in the present study were to investigate the distribution of pRNA nanoparticles after subconjunctival injection and examine the feasibility to deliver the nanoparticles to the cells of cornea and retina. Methods Alexa647-labeled pRNA nanoparticles (pRNA-3WJ and pRNA-X) and double-stranded RNA (dsRNA) were administered via subconjunctival injection in mice. Alexa647 dye was a control. Topical administration was performed for comparison. Ocular clearance of pRNA nanoparticles and dsRNA after the injection was assessed using whole-body fluorescence imaging of the eyes. The numbers of cells in the ocular tissues with nanoparticle cell internalization were determined in fluorescence microscopy of dissected eye tissues. Results After subconjunctival injection, pRNA nanoparticles and dsRNA were observed to distribute into the eyes and cleared through the lymph. pRNA-3WJ, pRNA-X, and dsRNA were found in the cells of the conjunctiva, cornea, and sclera, but only pRNA-X was in the cells of the retina. Topical administration was not effective in delivering the nanoparticles to the eye. Conclusions The pRNA nanoparticles were delivered to the cells in the eye via subconjunctival injection, and cell internalization was achieved in the cornea with pRNA-3WJ and pRNA-X and in the retina with pRNA-X. Only the X-shape pRNA-X could enter the retina.

Stable RNA nanoparticles as potential new generation drugs for cancer therapy

“…A recent study revealed that pRNA nanoparticles can be delivered to the posterior of the eye and internalized into cornea and retina cells after subconjunctival injection [190] (Fig. 11).…”

Recent perspectives on the delivery of biologics to back of the eye

“…Recently, Feng et al investigated the distribution and clearance of pRNA and dsRNA nanoparticles to the cornea and retina after subconjunctival injection. In vivo study was performed in mice and nanoparticles containing pRNA or dsRNA were labeled using Alexa647 for easy quantification and imaging [94]. Results indicated that pRNA and dsRNA were observed in sclera, corneal and conjunctiva cells, but only pRNA-X was detected in retinal cells [94].…”

“…In vivo study was performed in mice and nanoparticles containing pRNA or dsRNA were labeled using Alexa647 for easy quantification and imaging [94]. Results indicated that pRNA and dsRNA were observed in sclera, corneal and conjunctiva cells, but only pRNA-X was detected in retinal cells [94]. These results suggest that RNA therapy can be useful and delivered to the back-of-the-eye tissues for the treatment of posterior segment neovascular diseases.…”

Non-viral therapeutic approaches to ocular diseases: An overview and future directions

“…The injection of non-viral RNA particles in the subconjunctival space showed appreciable transfection of cells in the retina, but the majority of the particles migrated towards the cornea (88). It is therefore not surprising, that this method has been mainly used in the delivery of gene therapy vectors for the cornea (101, 102), especially as only very small particles (20 nm diameter) seem to be able to successfully penetrate into the inner ocular tissue (103).…”