Effects of proteinase-activated receptor 2 (PAR2) agonist peptide (AP) on Toll-like receptor 3 (TLR3) and interferon (IFN)α/βR signaling in human lung epithelial cell (EC) line. (a–d) PAR2 AP differentially regulates TLR3 signaling in human lung EC line. A549 cells were treated with medium, PAR2 AP (200 µM), poly I:C (pI:C; 100 µg ml−1), or both for the indicated time. Whole-cell lysates were subjected to SDS-polyacrylamide gel electrophoresis (SDS-PAGE) western immunoblot analysis. Data are representative of three separate experiments. (e) PAR2 AP fails to inhibit recombinant IFN-β (rIFN-β)-induced signal transducer and activator of transcription 1 (STAT1) phosphorylation in human lung EC line. A549 cells were treated with medium, PAR2 AP (200 µM), rIFN-β (100 U ml−1), or both for 15 min. Whole-cell lysates were subjected to SDS-PAGE western immunoblot analysis. Data are representative of three separate experiments.