Kidney-targeted liposome-mediated gene transfer in mice

To develop gene therapy targeted to the kidney, we compared three different routes of liposome-mediated gene delivery to the kidney in mice, ie intra-renal-pelvic, intra-renal-arterial, and intra-renal-parenchymal injections. A plasmid construct, pCMV beta gal, containing a cytomegalovirus (CMV) immediate-early gene promoter and a beta-galactosidase reporter gene was mixed with a 1:1 liposome mixture of N[1-(2,3-dioleoyloxy)propyl]-N,N,trimethylammonium chloride (DOTMA)/dioleoyl phosphatidyl ethanolamine (DOPE). The pCMV beta gal-liposome complex was injected into the left kidney via three different routes. The efficacy of gene transfer was assessed using 5-bromo-4-chloro-3-indolyl beta-D-galactopyranoside (X-gal) staining on frozen kidney sections 3 to 42 days after injections. Cells with beta-galactosidase activity were detected in the cortex and outer medulla in both intra-renal-pelvic and intra-renal-arterial groups, but not in the intra-renal-parenchymal group or in the contralateral noninjected kidney. Evidence of gene transfer was observed only in tubular epithelial cells, but not in glomerular, vascular, or interstitial compartments. The levels of beta-galactosidase expression started to decrease 3 weeks after injection. The gene transfer in the kidney was not associated with nephrotoxicity as assessed by blood urea nitrogen levels and renal histology. We conclude that both intra-renal-pelvic and intra-renal-arterial injections provide a transient gene transfer to the renal tubular cells and are suitable routes for kidney-targeted gene therapy.