Plasmid-mediated gene transfer of Cas9 induces vector-related but not SpCas9-related immune responses in human retinal pigment epithelial cells.

The clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (Cas9) system represents a powerful gene-editing tool and could enable treatment of blinding diseases of the retina. As a peptide of bacterial origin, we investigated the immunogenic potential of Cas9 in models of retinal immunocompetent cells: human microglia (IMhu) and ARPE-19 cells. Transfection with Streptococcus pyogenes-Cas9 expression plasmids (SpCas9 plasmid) induced Cas9 protein expression in both cell lines.

Challenges to Gene Editing Approaches in the Retina.

Retinal gene therapy has recently been at the cutting edge of clinical development in the diverse field of genetic therapies. The retina is an attractive target for genetic therapies such as gene editing due to the distinctive anatomical and immunological features of the eye, known as immune privilege, so that inherited retinal diseases (IRDs) have been studied in several clinical studies. Thus, rapid strides are being made toward developing targeted treatments for IRDs.