Towards gene therapy for renal diseases

The rationale of the somatic gene therapy is the correction of diseases at the most fundamental level. Ideal gene therapy should be achieved by the replacement of the wrong gene sequence of genome with correct one. However, the gene technology to date is yet immature so as to correct the wrong gene sequence in vivo. Potentially, the present technology of gene transfer may provide: 1) correction of cellular dysfunction by expressing the deficient gene; 2) addition of new function for a cell by transferring an exogenous gene; 3) inhibition of unfavorable action of a cell by introducing a counteracting gene. In nephrology, the gene transfer targeted kidney has been challenged at the experimental level. HVJ-liposome method and recombinant adenovirus allow gene transfer to the particular cells in kidney in vivo. Ex vivo gene transfer using mesangial cells and macrophages are another option. Transplant kidney is also a good material for genetic engineering. The potential application of gene transfer is enormous while the therapeutic application have just begun to explored. We have been devoted to HVJ-liposome mediated gene transfer to the kidney and successfully demonstrated the suppression of the extracellular matrix accumulation of the glomeruli in the experimental glomerulonephritis through inhibition of the TGF-beta action by antisense oligonucleotides or soluble type receptor chimera for TGF-beta. We also applied this technology to the inhibition of interstitial fibrosis in unilateral ureter obstruction model. The new HVJ-liposome method improved in lipid composition allows gene transfer to tubulointerstitial fibroblast by retrograde approach from ureter. In consequence, introduced TGF-beta antisense suppressed the TGF-beta mRNA in concomitant with ameliorating interstitial fibrosis. We believe that the gene transfer technique will become common strategy to study the molecular aspect of the renal diseases and will be possibly applicable to molecular intervention in nephrology.