Inhibition of PAX2 gene expression by siRNA (polyethylenimine) in experimental model of obstructive nephropathy

It was found that PAX2 (Paired Box 2) re-expression in renal tubular epithelial cells correlated with renal interstitial fibrosis of rats with obstructive nephropathy. The purpose of the present study was to identify whether RNA interference (RNAi) induced by polyethylenimine (jetPEI) could inhibit PAX2 gene re-expression and impact renal interstitial fibrosis of rats with obstructive nephropathy.

Four pairs of small interfering RNA (siRNA) interference sequences and a negative control were designed and synthesized according to the whole PAX2 gene mRNA sequence. siRNA was then transfected into renal capsule in a rodent model of unilateral ureteral obstruction (UUO), using in vivo jetPEI as delivery vector. The expression of PAX2 mRNA and protein in renal tissue was determined by real-time quantitative polymerase chain reaction (PCR) and Western blot, respectively. A carboxyfluorescein (FAM)-labeled negative control was also synthesized at the same time to identify transfection in vivo. Renal interstitial fibrosis was observed under light microscope after PAX2 gene silenced.

Green fluorescence was observed around renal tubule epithelial cells by fluorescence microscopy 3 days after the procedure validating the success of transfection. While the PAX2 gene expression was inhibited by all siRNA interference sequences, the strongest inhibition was observed with siRNA3. The PAX2 mRNA and protein were inhibited by 55% and 81%, respectively. Renal tubular damage and renal interstitial fibrosis were remitted obviously after PAX2 gene silenced.

siRNA was able to inhibit the expression of PAX2 in tubular epithelial cells in the UUO model. The siRNA may thus provide therapeutic potential for retarding the pathological progression of UUO.