TRIPLEX-FORMING OLIGONUCLEOTIDES CAN MODULATE AQUAPORIN-5 GENE-EXPRESSION IN EPITHELIAL-CELLS

Tripler-forming oligonucleotides (TFOs) may provide a useful approach to decrease gene transcription in vivo. We have identified two sequenc es in the rat aquaporin 5 (rAQP5) cDNA that are capable of forming a D NA triple helix. We designed four TFOs based on these sequences (a pur ine and a pyrimidine TFO per sequence). All four TFOs were able to bin d to the rAQP5 cDNA at varying efficiencies in vitro as measured by us ing gel mobility shift assays. The TFOs were delivered to intact MDCK epithelial cells via adenovirus-polylysine complexes. Experiments with fluorescein-isothiocyanate-labeled oligonucleotides delivered in this way showed primarily a nuclear localization. Three of the four TFOs i nternalized by adenovirus-polylysine complexes were capable of decreas ing rAQP5 expression in intact MDCK cells infected with a recombinant adenovirus encoding rAQP5. These data show that adenovirus-polylysine- TFO complexes can result in TFO delivery to the nucleus in intact epit helial cells and that TFOs may provide a useful way to selectively mod ulate rAQP5 gene expression.