High efficiency in vitro gene transfer into vascular tissues using a pseudotyped retroviral vector without pseudotransduction

Murine leukemia virus (MuLV)-derived retroviral vectors have had limited ap plication in vascular gene therapy because of low transduction efficiency o f vascular tissues, both in vitro and in vivo. In this study, we compared t he gene transfer efficiency of two retroviral vectors, amphotropic MuLV and a MuLV vector pseudotyped with the vesicular stomatitis virus G glycoprote in (VSV-G) envelope. Target vascular tissues included human endothelial cel ls (EC), smooth muscle cells (SMC) and saphenous veins (SV). Transduction e fficiency of human EC and SMC was significantly higher for VSV-G pseudotype d MuLV vector (90%) than for Amphotropic MuLV (20%). Luminal surface en fac e analysis of transduced cultured SV showed a six to 10-fold greater transd uction efficiency with VSV-G pseudotyped MuLV. The tissue plasminogen activ ator (tPA) gene was transduced into EC using each vector. Four days followi ng transduction, a 12-fold higher tPA antigen concentration and a 38-fold h igher enzymatic activity was measured from cells transduced with the VSV-G pseudotyped vectors as compared with the amphotropic MuLV. There was no det ectable pseudotransduction (protein transfer) associated with the VSV-G MuL V vector. Both AZT inhibition of reverse transcriptase and cell division ar rest by gamma irradiation inhibited transduction.