miR-221 is involved in HCMV induced type-I IFN production and ISG activation in NPCs. (A-B) NPCs were transfected with miR-221 mimic or mimic negative control, and infected with HCMV for indicated time. IFN-a and IFN-b mRNA expression was determined by qRT-PCR(A) and the levels of IFN-a and IFN-b cytokines in the cell culture supernatant was determined by enzyme-linked immunosorbent assay (ELISA)(B). (C-D) NPCs were transfected with miR-221 inhibitor or inhibitor negative control, and infected with HCMV for the indicated time. IFN-a and IFN-b mRNA expression was determined by qRT-PCR(C) and the levels of IFN-a and IFN-b cytokines in the cell culture supernatant was determined by enzyme-linked immunosorbent assay (ELISA)(D). (E-F) Experiments were performed as in A-D. Expression levels of ISG15, MxA and OAS were quantified by real-time PCR. All these experiments have been repeated three times, and the representative data were shown. (* p < 0.05, ** p < 0.01 vs mimics NC or inhibitor NC group).