Increasing Resistance of Tubular Epithelial Cells to Apoptosis by ShRNA Therapy Ameliorates Renal Ischemia-reperfusion Injury

Renal tubular epithelial cells (TEC) die by apoptosis or necrosis in renal ischemia-reperfusion injury (IRI). Fas/Fas ligand-dependent fratricide is critical in TEC apoptosis, and Fas promotes renal IRI. Therefore, targeting Fas or caspase-8 may have therapeutic potential for renal injury in kidney transplant or failure. RNA silencing by short hairpin RNA (shRNA) is a novel strategy to down-regulate protein expression. Using this approach, silencing of Fas or caspase-8 by shRNA to prevent TEC apoptosis and IRI was evaluated. IRI was induced by renal artery clamping for 45 or 60 min at 32 degrees C in uninephrectomized C57BL/6 mice. Here, we showed that Fas or pro-caspase-8 expression was significantly knocked down in TEC by stable expression of shRNA, resulting in resistance to apoptosis induced by superoxide, IFN-gamma/TNF-alpha and anti-Fas antibody. Inferior vena cava delivery of pHEX-small interfering RNA targeting Fas or pro-caspase-8 resulted in protection of kidney from IRI, indicated by reduction of renal tubular injury (necrosis and apoptosis) and serum creatinine or blood urea nitrogen. Our data suggest that shRNA-based therapy targeting Fas and caspase-8 in renal cells can lead to protection of kidney from IRI. Attenuation of pro-apoptotic proteins using genetic manipulation strategies such as shRNA might represent a novel strategy to promote kidney allograft survival from rejection or failure.