Induction of endogenous genes following infection of human endothelial cells with an E1(-) E4(+) adenovirus gene transfer vector

Recombinant adenovirus (Ad) gene transfer vectors are effective at transfer ring exogenous genes to a variety of cells and tissue types both in vitro a nd in vivo. However, in the process of gene transfer, the Ad vectors induce the expression of target cell genes, some of which may modify the function of the target cell and/or alter the local milieu. To develop a broader und erstanding of Ad vector-mediated induction of endogenous gene expression, g enes induced by first-generation E1(-) E4(+) Ad vectors in primary human um bilical vein endothelial cells were identified by cDNA subtraction cloning. The identified cDNAs included signaling molecules (lymphoid blast crisis [ LBC], guanine nucleotide binding protein alpha type S [G alpha-S], and mito gen kinase [MEK5]), calcium-regulated/cytoskeletal proteins (calpactin p11 and p36 subunits, vinculin, and spinocerebellar ataxia [SCA1]), growth fact ors (insulin-like growth factor binding protein 4 and transforming growth f actor Pt), glyceraldehyde-6-phosphate dehydrogenase, an expressed sequence tag, and a novel cDNA showing homology to a LIM domain sequence. Two- to se venfold induction of the endogenous gene expression was observed at 24 h po stinfection, and induction continued up to 72 h, although the timing of gen e expression varied among the identified genes. In contrast to that observe d in endothelial cells, the Ad vector-mediated induction of gene expression was not found following Ad vector infection of primary human dermal fibrob lasts or human alveolar macrophages, Empty Ad capsids did not induce endoge nous gene expression in endothelial cells. Interestingly, additional deleti on of the E4 gene obviated the upregulation of genes in endothelial cells b y the E1(-) E3(-) Ad vector, suggesting that genes carried by the E4 region play a central role in modifying target cell gene expression. These findin gs are consistent with the notion that efficient transfer of exogenous gene s to endothelial cells by first-generation Ad vectors comes with the price that these vectors also induce the expression of a variety of cellular gene s.