Application of small interfering RNA (siRNA) for modulation of airway epithelial gene expression.

Small interfering RNA (siRNA) was developed as a novel tool to inhibit gene function in human disease. The aim of the present study was to modify the function of NF-kappaB in airway epithelial cells by application of siRNA. 1HAEo cells were transfected with siRNA directed to the p65 subunit of NF- kappaB (siRNA.p65). Application of siRNA.p65 caused decreased levels of p65 mRNA or protein after 72 hours, as determined by quantitative RT-PCR or Western blot analysis. The tumor necrosis factor- alpha (TNF-alpha)-induced release of interleukin-6 (IL-6) and IL-8 was significantly inhibited by the application of siRNA.p65. Well-differentiated primary cells were resistant to transfection with siRNA.p65. However, when undifferentiated primary cells were transfected, an effect of the siRNA could still be observed when the cells were differentiated in an air-liquid interface culture system. In conclusion, siRNA can be used to regulate the activity of NF-kappaB in airway epithelial cells.