Microsphere-adenoviral complexes target and transduce the glomerulus in vivo.

BACKGROUND: Developing new treatments for glomerulonephritis makes the glomerulus a logical target for gene therapy. Microspheres may lodge in the glomerulus, and replication-deficient recombinant adenoviruses are potent mediators 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-galactosidase (beta-gal) transgene expression cassette, were complexed to polystyrene microspheres. To assess in vivo glomerular transduction with this tool, male Sprague-Dawley rats underwent aortic injections with adenovirus linked to 11 or 16 microm diameter microspheres. RESULTS: After 48 hours, adenoviral-microsphere complexes resulted in transduction of up to 19% of glomeruli per kidney section. Endothelial and mesangial cells were transduced with this approach, and transprotein expression persisted for 21 days. Transduction efficiency was greater in the 16 microm group. For all rats, there was a strong correlation between kidney luciferase levels and the number of beta-gal-positive glomeruli (r = 0.87), indicating that transgene expression was primarily glomerular in location. This was supported by reverse transcriptase in situ polymerase chain reaction, which demonstrated glomerular localization of the beta-gal transgene. CONCLUSIONS: The aortic injection of adenoviral-microsphere complexes transduces the glomerulus in vivo and may be a useful tool in developing approaches to gene therapy of glomerular disease.

Successful DNA transfer in cultured human mesangial cells using replication deficient recombinant adenovirus.

BACKGROUND: Efficient transfer of DNA into human mesangial cells is an essential first step in the development of gene therapies for mesangial cell-mediated glomerulopathies. In the present studies, we assessed the ability of replication deficient recombinant adenovirus to transfer DNA (transduce) into primary cultures of human mesangial cells. METHODS: Primary cultures of human mesangial cells were transduced with an adenoviral vector (rAv beta-gal) containing a CMVllacZ promoter-reporter expression cassette coding for beta-galactosidase (beta-gal). We assessed soluble and histologic beta-gal activity, morphology, and phenotypic expression of mesangial cell transductants, durability of transduced mesangial cells by measuring transgene expression following trypsinization or after prolonged periods in culture and metabolic stability following transduction (as assessed by fibronectin biosynthesis). RESULTS: We showed that rAv beta-gal efficiently transduced mesangial cells in a dose-dependent fashion at a multiplicity of infectious units (MOI) ranging from 1 to 400 plaque forming units/cell (pfu/cell). One hundred percent of mesangial cells were transduced at an MOI of 100 pfu/cell. By electron microscopic evaluation, viral particles of approximately 85-90 nm were demonstrated in the cytoplasm of transduced cells. Following transduction, legal levels rose rapidly and were 10-fold greater than baseline levels after 2 hours. Beta-gal levels continued to rise for 7 days following transduction. Transduction with rAv beta-gal was well tolerated; mesangial cell transductants maintained normal morphology and phenotype, tolerated 3 cycles of trypsinization and maintained normal constitutive production of fibronectin. CONCLUSIONS: Gene transfer with adenovirus is an effective, well tolerated approach for introducing DNA into primary cultures of human mesangial cells.