Gene therapy brings a ray of hope for inherited ocular diseases that may cause severe vision loss and even blindness. However, due to the dynamic and static absorption barriers, it is challenging to deliver genes to the posterior segment of the eye by topical instillation. To circumvent this limitation, we developed a penetratin derivative (89WP)-modified polyamidoamine polyplex to deliver small interference RNA (siRNA) via eye drops to achieve effective gene silencing in orthotopic retinoblastoma. The polyplex could be spontaneously assembled through electrostatic and hydrophobic interactions, as demonstrated by isothermal titration calorimetry, and enter cells intactly. In vitro cellular internalization revealed that the polyplex possessed higher permeability and safety than the lipoplex composed of commercial cationic liposomes. After the polyplex was instilled in the conjunctival sac of the mice, the distribution of siRNA in the fundus oculi was significantly increased, and the bioluminescence from orthotopic retinoblastoma was effectively inhibited. In this work, an evolved cell-penetrating peptide was employed to modify the siRNA vector in a simple and effective way, and the formed polyplex interfered with intraocular protein expression successfully via noninvasive administration, which showed a promising prospect for gene therapy for inherited ocular diseases.
Keywords: gene delivery; intraocular drug delivery; noninvasive administration; nonviral vector; penetratin derivative; siRNA.