Virus-mediated gene transfer of recombinant soluble adhesion molecules to the vessel wall and synovium.

Abstract

Adhesion molecules expressed on a variety of cell types interact with their counter-receptors on cells of the immune system in the context of important physiological and pathological processes. These molecular interactions specifically mediate several inflammatory diseases including atherosclerosis, asthma, rheumatoid arthritis, and tumor metastasis. The hypothesis of introducing a potential therapeutic reagent, recombinant soluble adhesion molecules to block the cell-cell interaction was examined. Recombinant soluble ICAM-1 and VCAM-1 were generated by introducing a stop codon at the conjunction of extra-cellular domain and transmembrane domain of the wild type gene. Expression and secretion of the soluble CAMs was studied in cells stably transfected with slCAM or sVCAM expressing vectors. Biological function of slCAM and sVCAM was demonstrated by their ability to partially interfere with the interaction between endothelial and leukocyte cell lines. For delivery of soluble adhesion molecule in vivo as a strategy for gene therapy, a recombinant adenovirus carrying sVCAM, Ad.CBsVCAM, was constructed. The immunological and biochemical characteristics of sVCAM was identified by immunohistochemical staining, immunoprecipitation and in vitro binding assay. Both in vivo and ex vivo approaches of gene therapy was attempted. Expression of a reporter gene, $\beta$-galactosidase, and sVCAM was demonstrated in both endothelial cells and smooth muscle cells of iliac artery directly infused with recombinant adenovirus through a double balloon catheter as well as jugular vein grafts infected with virus in vitro followed by interposition to carotid artery in a swine model. The viruses were also injected intra-articularly to rabbit synovium as a model system for studying and potentially treating inflammatory arthropathies such as rheumatoid arthritis. Significant transgene expression in synovial tissue at least 2 weeks post infusion and high level secretion of sVCAM was observed in the synovial fluid 4 days post infusion. The experiments demonstrated the feasibility of gene transfer to cells of the vessel wall and synovium tissue by adenovirus-mediated gene transfer.