Microsphere-adenoviral complexes target and transduce the glomerulus in vivo

Background. Developing new treatments for glomerulonephritis makes the glom erulus a logical target for gene therapy. Microspheres may lodge in the glo merulus, and replication-deficient recombinant adenoviruses are potent medi ators of gene transfer. We postulated that adenoviral-microsphere complexes could result in DNA transfer (transduction) into glomerular cells in vivo. Methods. Two adenoviruses, each one containing a luciferase or beta-galacto sidase (beta-gal) transgene expression cassette, were complexed to polystyr ene microspheres. To assess in vivo glomerular transduction with this tool, male Sprague-Dawley rats underwent aortic injections with adenovirus linke d to 11 or 16 mu m diameter microspheres. Results. After 48 hours, adenoviral-microsphere complexes resulted in trans duction of up to 19% of glomeruli per kidney section. Endothelial and mesan gial cells were transduced with this approach, and transprotein expression persisted for 21 days. Transduction efficiency was greater in the 16 mu m g roup. For all rats, there was a strong correlation between kidney luciferas e levels and the number of beta-gal-positive glomeruli (r = 0.87), indicati ng that transgene expression was primarily glomerular in location. This was supported by reverse transcriptase in situ polymerase chain reaction, whic h demonstrated glomerular localization of the beta-gal transgene. Conclusions. The aortic injection of adenoviral-microsphere complexes trans duces the glomerulus in vivo and may be a useful tool in developing approac hes to gene therapy of glomerular disease.