Endothelial Retargeting of AAV9 In Vivo

Adeno‐associated viruses (AAVs) are frequently used for gene transfer and gene editing in vivo, except for endothelial cells, which are remarkably resistant to unmodified AAV‐transduction. AAVs are retargeted here toward endothelial cells by coating with second‐generation polyamidoamine dendrimers (G2) linked to endothelial‐affine peptides (CNN). G2(CNN) AAV9‐Cre (encoding Cre recombinase) are injected into mTmG‐mice or mTmG‐pigs, cell‐specifically converting red to green fluorescence upon Cre‐activity. Three endothelial‐specific functions are assessed: in vivo quantification of adherent leukocytes after systemic injection of ‐ G2(CNN) AAV9 encoding 1) an artificial adhesion molecule (S1FG) in wildtype mice (day 10) or 2) anti‐inflammatory Annexin A1 (Anxa1) in ApoE(−/−) mice (day 28). Moreover, 3) in Cas9‐transgenic mice, blood pressure is monitored till day 56 after systemic application of G2(CNN) AAV9‐gRNAs, targeting exons 6–10 of endothelial nitric oxide synthase (eNOS), a vasodilatory enzyme. G2(CNN) AAV9‐Cre transduces microvascular endothelial cells in mTmG‐mice or mTmG‐pigs. Functionally, G2(CNN) AAV9‐S1FG mediates S1FG‐leukocyte adhesion, whereas G2(CNN) AAV9‐Anxa1‐application reduces long‐term leukocyte recruitment. Moreover, blood pressure increases in Cas9‐expressing mice subjected to G2(CNN) AAV9‐gRNA(eNOS). Therefore, G2(CNN) AAV9 may enable gene transfer in vascular and atherosclerosis models.