Transduction of renal cells in vitro and in vivo by adeno-associated virusgene-therapy vectors

There has been an increasing interest recently in the possibility of treati ng renal diseases using gene therapy. The ability to pursue gene therapy fo r renal diseases has been limited by the availability of an adequate system for gene delivery to the kidney. Adeno-associated virus (AAV)is a defectiv e virus of the parvovirus family that has a number of properties attractive for renal gene delivery: recombinant AAV contains no viral genes; expressi on of genes delivered by these vectors does not activate cell-mediated immu nity; the virus is able to transduce nondividing as well as dividing cells; and both wild-type and recombinant AAV integrate into the host chromosome resulting in long-term gene expression. Studies were performed to determine whether AAV can deliver reporter genes to kidney cells in vitro and in viv o. These studies show that AAV can deliver reporter genes with approximatel y equal efficiency to human mesangial, proximal tubule, thick ascending lim b, collecting tubule, and renal cell carcinoma cells in primary culture. Im mortalized mouse mesangial cells are transduced at a much greater efficienc y. Transduction can be enhanced by pharmaceutical agents up to sevenfold in primary cells (transducing up to 20% of primary cells per well) and as muc h as 400-fold in immortalized mesangial cells. AAV delivered lit vivo by in traparenchymal injection results in at least 3 mo of reporter gene expressi on in tubular epithelial, but not glomerular or vascular, cells at the inje ction site. These data indicate that AAV can deliver genes to renal cells b oth in vitro and in vivo resulting in prolonged gene expression, and thus A AV can be a useful tool for renal gene delivery.