Cell-Penetrating Chaperone Nuc1 for Small- and Large-Molecule Delivery Into Retinal Cells and Tissues

Area of Science:

• Ophthalmology
• Biotechnology
• Molecular Biology

Background:

• Efficient in vivo delivery of therapeutic molecules to retinal cells remains a significant challenge.
• Current methods, like cell-penetrating peptides, often require conjugation, which can impair therapeutic protein function.

Purpose of the Study:

• To develop a novel peptide (Nuc1) for efficient, conjugation-free delivery of diverse molecules into retinal cells in vivo.
• To evaluate Nuc1's potential for delivering proteins, antibodies, and viral vectors across biological membranes.

Main Methods:

• Nuc1 peptide was designed to target retinal cell surface receptors (heparan sulfate proteoglycans and nucleolin).
• Nuc1 was administered via intravitreal injection in mice, co-administered with various molecules.
• Retinal uptake and functional outcomes of delivered molecules were assessed.

Main Results:

• Nuc1 facilitates cellular entry via macropinocytosis.
• Delivered recombinant X-linked inhibitor of apoptosis protein inhibited photoreceptor apoptosis.
• Nuc1 enhanced anti-VEGF antibody delivery in age-related macular degeneration (AMD) models, reducing neovascularization and fibrosis.
• Nuc1 improved adeno-associated virus (AAV) penetration into retinal cells via subretinal and intravitreal routes.

Conclusions:

• Nuc1 represents a promising, conjugation-free strategy for in vivo retinal delivery of therapeutics.
• This approach has broad applicability for delivering proteins, antibodies, and gene therapy vectors to the retina.