Figure 6.

Formyl peptide receptor antagonists dampen Ent mediated IL-8 secretion in IECs. (a) HT29 cell monolayer were pre-treated with pan-FPR inhibitor Boc2 (0–50 µM, 1 h) and then stimulated with Ent (25 µM) for 24 h in serum-free media supplemented with 1% penicillin-streptomycin. Culture supernatants were analyzed for IL-8 secretion. (b) HT29 cells were pre-incubated with Boc2 (10 µM, 1 h) and then treated with Ent (0–25 µM) for 24 h. IL-8 was measured in culture supernatants. (c) HT29 cells were pre-incubated with a potent and selective FPR1 antagonist CspH (0–10 µM) for 1 h and then treated with Ent (25 µM) for 24 h in serum-free media supplemented with 1% penicillin-streptomycin. Culture supernatants were assayed for IL-8 via ELISA. (d) IECs were stimulated with CspH (1 µM) for 1 h and then treated with Ent (0–25 µM) for 24 h in serum-free media supplemented with 1% penicillin-streptomycin. Bar graphs represent the secretion of IL-8 in culture supernatant. Con denotes cells treated with DMSO as vehicle control. (e) The colon section (2 cm below the cecum) from WT, Fpr1KO and Myd88KO mice (n = 5–6, male, 8 wks old) were collected and cultured in serum-free media supplemented with 1% penicillin-streptomycin for 24 h, then stimulated with Ent (25 µM) or with DMSO as vehicle control (Con). The culture supernatants were collected and analyzed for keratinocyte-derived chemokine CXCL1 (KC). Line graphs represent the induction of KC of a sample pair (DMSO or Ent treated) from each mouse. In vitro assays were performed in triplicates and data represented as mean ± SEM. * p < .05, **p < .01 and *** p < .001