Efficient and selective AAV2-mediated gene transfer directed to human vascular endothelial cells

Gene therapy vectors based on adeno-associated virus-2 (AAV2) offer conside rable promise for human gene therapy. Applications for AAV vectors are limi ted to tissues efficiently transduced by the vector due to its natural trop ism, which is predominantly skeletal muscle, neurons, and hepatocytes. Trop ism modification to elevate efficiency and/or selectivity to individual cel l types would enhance the scope of AAV for disease therapies. The vascular endothelium is implicitly important in cardiovascular diseases and cancer, but is relatively poorly transduced by AAV vectors. We therefore geneticall y incorporated the peptide SIGYPLP, which targets endothelial cells (EC), i nto position I-587 of AAV capsids. SIGYPLP-modified AAV (AAVsig) showed enh anced transduction of human EC compared with AAV with a wild-type capsid (A AVwt), a phenotype independent of heparan sulphate proteoglycan (HSPG) bind ing. In contrast, AAVsig did not enhance transduction of primary human vasc ular smooth muscle cells or human hepatocytes, principal targets for AAV ve ctors in local or systemic gene delivery applications, respectively. Furthe rmore, infection of EC in the presence of bafilomycin A(2) indicated that i ntracellular trafficking of AAV particles was altered by targeting AAV by m eans of SIGYPLP. AAV vectors with enhanced tropism for EC will be useful fo r diverse gene therapeutics targeted at the vasculature.