Fig. 5.

WISP1-induced cytokine and chemokine production in LPS-primed peritoneal macrophages requires integrin β5. Peritoneal macrophages (PM) treated with LPS (0.1 μg/ml) followed by WISP1 (10 μg/ml) exposure at 4 h. Supernatants collected at 2 h intervals from 4 to 10 h following WISP1 stimulation. Cytokines (TNF-α and IL-6) and chemokines (MIP-2 and MCP-1) in supernatant detected by ELISA. PM receiving combination of LPS + WISP1 (L + W) from wildtype mice (WT) compared to PM from subgroup of either TLR4 ^−/− mice or wildtype mice receiving integrin β5 siRNA transfection (or control siRNA) subjected to LPS or WISP1. LPS-induced increases in IL-6, TNF-α, MIP-2 and MCP-1 evident within 4–10 h and addition of WISP1 induced further increases in all four mediators. Suppression of integrin β5 expression prevented WISP1-induced enhancement of LPS induction in four mediators. *P < 0.05 compared with LPS alone at 8 h; **P < 0.05 compared with L + W WT at 8 h; ***P < 0.05 compared with L + W WT; ^#P < 0.05 compared with LPS alone at 10 h; ^##P < 0.05 compared with L + W WT at 10 h; ^### P < 0.05 compared with L + W WT at 10 h. Ctl, control, IL interleukin, KO knockout, LPS lipopolysaccharide, MCP-1 monocyte chemoattractant protein-1, MIP-2 macrophage inflammatory protein-1, PBS phosphate buffered saline, siRNA small interfering RNA, TNF-α tumor necrosis factor alpha, WISP1 WNT1 inducible secreted protein