Different dynamic induction of miR-155* and miR-155 by TLR7 and IFNα. (A-B) Kinetic analysis of TLR7 and IFN-α induction of pri-miR-155, mature miR-155, and mature miR-155*. Human PDCs were stimulated with R837 (A) or IFN-α (B) over a 24-hour time course and harvested at the indicated time points. miR-155* and miR-155 were analyzed with the TaqMan MicroRNA Expression Assay and normalized to the RNU48 levels. Pri-miR-155 mRNA was detected by qRT-PCR and normalized to the RPL13a RNA levels. The graph shows the fold induction calculated by normalizing the relative expression values at different time points to the 0-hour values. (C-D) IFN-α and TLR ligands had opposite effects on the change in the ratios of miR-155* to miR-155. Purified PDCs were stimulated with either IFN-α or R837 over a 24-hour time course and harvested at the indicated time points. miR-155* and miR-155 were analyzed with the TaqMan MicroRNA Expression Assay and normalized to the RNU48 levels. The ratios of miR-155* to miR-155 were calculated. The graph shows the fold changes after the ratios at different time points were normalized to the 0-hour ratio. (E) IFN-α mRNAs from panel A were detected by qRT-PCR and normalized to RPL13a RNA levels. (F) IFN-α in the supernatant of panel A was detected by ELISA. The data are representative of at least 3 independent experiments, each based on a different PDC preparation.