Retinal Penetrating Adeno-Associated Virus

Area of Science:

• Ophthalmology
• Gene Therapy
• Molecular Biology

Background:

• Current gene delivery to the outer retina commonly uses subretinal injection of adeno-associated virus (AAV).
• Intravitreal injections are a more common and less invasive method for retinal drug delivery.
• Developing intravitreal AAV vectors is crucial for advancing retinal gene therapy.

Purpose of the Study:

• To engineer AAV vectors capable of reaching the outer retina following intravitreal administration.
• To assess the efficacy of modified AAV vectors for gene delivery to retinal cells.

Main Methods:

• A molecular chaperone (Nuc1) and its truncated version (IKV) were genetically incorporated into AAV2/9 VP1 protein.
• Recombinant AAV vectors encoding GFP or Nrf2 were constructed with IKV modification.
• These vectors were administered via intravitreal injection into mice, and gene expression and oxidative stress markers were quantified.

Main Results:

• AAV2/9 vectors with full Nuc1 did not yield significant retinal gene expression.
• AAV2/9 vectors with the IKV modification demonstrated robust green fluorescent protein (GFP) expression in photoreceptors and retinal pigment epithelium (RPE) after intravitreal injection.
• Intravitreal delivery of Nrf2 using IKV-modified AAV vectors reduced oxidative stress in the retina.

Conclusions:

• A novel AAV vector incorporating IKV enables efficient gene delivery to the outer retina (photoreceptors and RPE) via intravitreal injection in a murine model.
• This engineered vector represents a promising advancement for non-invasive gene therapy strategies targeting retinal diseases.