LIPOADENOFECTION-MEDIATED GENE DELIVERY TO THE CORNEAL ENDOTHELIUM - PROSPECTS FOR MODULATING GRAFT-REJECTION

Background. Gene transfer to the corneal endothelium has potential for the prevention or reversal of corneal allograft rejection. Previous w ork has examined adenoviral vectors for gene transfer to endothelium, These have a number of theoretical and practical disadvantages, both f or experimental and clinical applications. We have therefore used lipo adenofection, in which plasmid DNA is delivered using a combination of liposomes and adenovirus, to transfer marker genes to the cornea, Met hods. Corneas were obtained from New Zealand White rabbits and culture d ex vivo using standard conditions, The corneas were transfected usin g either lipofection or Lipoadenofection with plasmids encoding marker genes. The efficiency of gene transfer and the location and kinetics of gene expression were determined, We also investigated the delivery of a gene construct containing an inducible promoter that is activated by tumor necrosis factor (TNF), to determine whether expression of th e relevant genes could be controlled by exogenous factors such as cyto kines. Results. This study shows that gene expression is limited to th e endothelium and that expression is transient. Furthermore, we have s hown that expression of a gene controlled by an inducible promoter onl y occurs when TNF is present; Conclusions. These data indicate that li pofection is an efficient method to transfer therapeutic genes to the corneal epithelium, and that it can be used to transfer constructs tha t utilize an inducible promoter controlled by TNF. As TNF is present i n the aqueous humor during allograft rejection, and this is in contact with the corneal endothelium, this has the potential to restrict expr ession of a therapeutic gene to rejection episodes in the cornea.