AAV2-Retro-Mediated Gene Transfer Selectively Targets Outer Retinal Cells Following Intravitreal Injection

Area of Science:

• Ophthalmology
• Gene Therapy
• Molecular Biology

Background:

• Intravitreal gene delivery is crucial for treating retinal diseases.
• Conventional adeno-associated virus (AAV) vectors often require subretinal injection for efficient outer retinal transduction.
• Minimally invasive delivery methods with improved tropism are needed.

Purpose of the Study:

• To investigate the cellular tropism and temporal dynamics of adeno-associated virus 2 (AAV2)-retro gene delivery.
• To evaluate AAV2-retro's efficiency and specificity following intravitreal injection in adult mouse retinas.

Main Methods:

• Adult C57BL/6J mice received intravitreal injections of AAV2-retro carrying the mGreenLantern reporter gene.
• Retinas were analyzed at 1, 3, and 14 days post-injection using immunofluorescence.
• Transduced cell types were identified using specific cell markers; transduction efficiency and distribution were quantified.

Main Results:

• AAV2-retro efficiently transduced photoreceptors and retinal pigment epithelium (RPE), including rods and cones.
• Outer retinal expression was robust, with limited transduction in inner retinal cells, indicating high cell-type specificity.
• Intravitreal AAV2-retro achieved widespread retinal distribution, surpassing conventional AAV2 subretinal delivery patterns. Sequential injections enhanced expression and coverage.

Conclusions:

• AAV2-retro facilitates efficient and outer retina-specific gene delivery through intravitreal administration.
• This method presents a minimally invasive alternative to subretinal injections for retinal gene transfer.
• AAV2-retro holds promise for preclinical retinal degeneration studies and gene therapies targeting photoreceptor and RPE function.