Late-breaking abstract: High-efficacy transduction of tyrosine-mutant adeno-associated virus serotype 8 vector in pulmonary gene therapy

Vectors derived from adeno-associated viruses (AAV) have become important gene delivery tools for the treatment of many pulmonary diseases. Phosphorylation of surface-exposed tyrosine residues from AAV capsid targets the viral particles for ubiquitination and proteasome-mediated degradation, and mutations of these tyrosine residues lead to highly efficient vector transduction in vitro and in vivo in different organs. The purpose of this study was to evaluate the pulmonary transduction efficacy of AAV8 vectors containing point mutations in surface-exposed capsid tyrosine residues. Forty-eight C57BL/6 mice were randomly assigned into three groups: 1) control group (CTRL) animals submitted to intratracheal instillation of saline, 2) wild-type AAV8 group (WT-AAV8, 1010 vg) and 3) capsid-mutant Y733F AAV8 group (M-AAV8, 1010 vg) that received (it) AAV8 vectors containing the DNA sequence of enhanced green fluorescence protein (eGFP). Four weeks after instillation, lung mechanics and morphometry, vector transduction and the inflammatory profile were analyzed. Tyrosine-mutant AAV8 vector displayed significantly increased transduction efficacy in the lung compared with their wild-type counterparts. No significant differences were observed in lung mechanics and morphometry among experimental groups. Furthermore, there was no evidence of inflammatory response in any group. Delivery of tyrosine mutant AAV8 vector led to a more effective eGFP expression in mouse lung than wild-type, suggesting a more efficient transduction. In conclusion, AAV8 vectors may be useful as new therapeutic strategies for the treatment of pulmonary diseases. Supported by: CAPES, FAPERJ, CNPq.