Facile Noninvasive Retinal Gene Delivery Enabled by Penetratin

Abstract

Gene delivery to the posterior segment of the eye is severely hindered by the impermeability of defensive barriers; therefore, in clinical settings, genomic medicines are mainly administered by intravitreal injection. We previously found that penetratin could transport the covalently conjugated fluorophore to the fundus oculi by topical instillation. In this study, gene delivery systems enabled by penetratin were designed based on electrostatic binding to target the retina via a noninvasive administration route and prepared with red fluorescent protein plasmid (pRFP) and/or poly(amidoamine) dendrimer of low molecular weight (G3 PAMAM). Formulation optimization, structure confirmation, and characterization were subsequently conducted. Penetratin alone showed limited ability to condense the plasmid but had powerful uptake and transfection by corneal and conjunctival cells. G3 PAMAM was nontoxic to the ocular cells, and when introduced into the penetratin-incorporated complex, the plasmid was condensed more compactly. Therefore, further improved cellular uptake and transfection were observed. After being instilled in the conjunctival sac of rats, the intact complexes penetrated rapidly from the ocular surface into the fundus and resided in the retina for more than 8 h, which resulted in efficient expression of RFP in the posterior segment. Intraocular distribution of the complexes suggested that the plasmids were absorbed into the eyes through a noncorneal pathway during which penetratin played a crucial role. This study provides a facile and friendly approach for intraocular gene delivery and is an important step toward the development of noninvasive gene therapy for posterior segment diseases.

A Phage Lysin Fused to a Cell-Penetrating Peptide Kills Intracellular Methicillin-Resistant Staphylococcus aureus in Keratinocytes and Has Potential as a Treatment for Skin Infections in Mice

“…Moreover, lysins are rarely relied on to get rid of intracellular bacteria because they do not possess the ability to penetrate eukaryotic cells (14,20). So far, many studies have disclosed that cell-penetrating peptides (CPPs) are short peptides that are able to penetrate biological membranes and drive the bioactive cargo into the cells by internalization (21)(22)(23). Specifically, many types of drugs have been transported into cells using CPPs, including antisense oligonucleotides, small-molecule pharmaceuticals, and therapeutic proteins (24).…”

Peptidomimetics Therapeutics for Retinal Disease

“…Complexes of penetratin/Red Fluorescent Protein expressing plasmid (pRFP) with and without poly(amidoamine) (PAMAM) were administered via topical instillation to the rat conjunctival sac. [158] After consecutive administrations every 8 h for 3 days, both penetratin/pRFP and penetratin/PAMAM/pRFP expressed fluorescent protein in the retina. The addition of PAMAM for particle condensation enhanced the gene delivery efficiency.…”

Breaking down the Barrier: Topical Liposomes as Nanocarriers for Drug Delivery into the Posterior Segment of the Eyeball

“…Transport study results showed that dendrimer complexation increases DEX transport across both corneal and scleral tissues. Additionally, dendrimers have proven their efficiency to release genetic material when topically administered [114].…”