Endothelium-specific in vivo gene transfer

Area of Science:

• Vascular Biology
• Gene Therapy
• Animal Models

Background:

• Targeted gene expression in vascular endothelium is crucial for studying endothelial cell (EC) biology.
• Developing efficient and specific methods for EC gene transfer is essential for in vivo research.

Purpose of the Study:

• To develop and characterize an efficient somatic transgenic model for EC-specific gene transfer.
• To evaluate the efficiency, specificity, and toxicity of adenovirus-mediated gene transfer in rat carotid arteries.

Main Methods:

• Adenovirus expressing beta-galactosidase (beta-gal) gene was infused into rat carotid arteries.
• Gene expression, cell-type specificity, and toxicity were assessed via beta-gal activity assays and cell counting.
• Vascular cell proliferation was measured using bromodeoxyuridine and [3H]thymidine incorporation.

Main Results:

• Optimal gene transfer achieved with 1-10 x 10^10 to 1 x 10^11 plaque-forming units (pfu)/mL, transducing ~35% of luminal ECs with 90-98% EC specificity.
• Higher viral concentrations (>4 x 10^10 pfu/mL) reduced EC number significantly (97% decrease).
• Gene transfer at 4 x 10^10 pfu/mL was efficient, preserved ECs, caused minimal neointimal formation, but increased EC and smooth muscle cell proliferation early on, with only EC proliferation remaining elevated at 14 days.

Conclusions:

• A novel animal model enables efficient and highly EC-specific gene transfer in vivo.
• The model demonstrates minimal vascular toxicity but an elevated EC proliferative index.
• This model is valuable for elucidating EC gene function, regulation, and signal transduction pathways.