Adenovirus vectors targeting alpha(v) integrin or heparan sulfate receptors display different distribution of transgene activity after intramuscular injection (original) (raw)

Background: Modification of the fiber proteins in replication-deficient adenoviral (Ad) vectors through incorporation of specific receptor-binding motifs may represent a strategy to enhance their tissue targeting capabilities.Modification of the fiber proteins in replication-deficient adenoviral (Ad) vectors through incorporation of specific receptor-binding motifs may represent a strategy to enhance their tissue targeting capabilities.Methods: In this study, we compared an unmodified Ad (GV10) with two mutated vectors obtained by insertion of specific target sequences that redirect binding, either toward αV integrin (RGD) or heparan sulfate (UTV) cellular receptors, for reporter gene expression spatial distribution in the rabbit skeletal muscle. In a first series of experiments, injection volume was kept constant and activity of a lacZ transgene was evaluated 48 h after injection of the Ad vectors at different doses. In separate experiments, the effects of different volumes of injection at a constant dose of Ad vector were monitored.In this study, we compared an unmodified Ad (GV10) with two mutated vectors obtained by insertion of specific target sequences that redirect binding, either toward αV integrin (RGD) or heparan sulfate (UTV) cellular receptors, for reporter gene expression spatial distribution in the rabbit skeletal muscle. In a first series of experiments, injection volume was kept constant and activity of a lacZ transgene was evaluated 48 h after injection of the Ad vectors at different doses. In separate experiments, the effects of different volumes of injection at a constant dose of Ad vector were monitored.ResultsAll vectors evaluated showed a significant increase in the number of lacZ-positive muscle segments, with increasing vector dose. However, in muscles treated with the UTV vector, fewer muscle fibers were β-gal-positive than in GV10 or RGD vector treated animals. In fact, total β-gal activity increased in a dose-dependent fashion in the GV10- and RGD-treated muscles, but not in the UTV-treated ones. Remarkably, in samples from UTV-treated animals, a volume-dependent enhancement of transgene expression was observed during experiments performed at the same dose and different injection volumes.All vectors evaluated showed a significant increase in the number of lacZ-positive muscle segments, with increasing vector dose. However, in muscles treated with the UTV vector, fewer muscle fibers were β-gal-positive than in GV10 or RGD vector treated animals. In fact, total β-gal activity increased in a dose-dependent fashion in the GV10- and RGD-treated muscles, but not in the UTV-treated ones. Remarkably, in samples from UTV-treated animals, a volume-dependent enhancement of transgene expression was observed during experiments performed at the same dose and different injection volumes .Conclusions: The results of the present study demonstrate that altering Ad affinity for cellular receptors modulates the level and distribution of transgene activity, conferring characteristics that may allow for treatment customization. Copyright © 2004 John Wiley & Sons, Ltd.The results of the present study demonstrate that altering Ad affinity for cellular receptors modulates the level and distribution of transgene activity, conferring characteristics that may allow for treatment customization. Copyright © 2004 John Wiley & Sons, Ltd.