Fig. 6.

SIRT1 suppresses virus-induced cytokine production and protects cells from dsRNA-induced apoptosis. HaCaT keratinocytes were transfected with control siRNA and SIRT1 specific siRNA molecules. After 24 h of silencing, the cells were transfected with pI:C for 5 h (A) or infected with EMCV for 15 h (B), and the effect of SIRT1 silencing on induced cytokine expression was detected using quantitative RT-PCR. Comparable data were obtained from two separate experiments. *p < 0.05 versus pI:C-transfected or EMCV-infected ctr-siRNA sample. C, the effect of SIRT1 silencing on dsRNA-induced caspase-3 activation was detected via Western blotting. GAPDH detection was used to confirm the equal loading. HaCaT cells were pretreated with SIRT1 inhibitor (Sirtinol) or activator (SRT1720) for 1 h before stimulation with cytoplasmic pI:C for 17 h (D) or infection with EMCV for 15 h (E). The formation of the active form of caspase-3 and tBid was analyzed via Western blotting. Silver stained gel and GAPDH detection were used to confirm the equal loading.