Fig. 3

RASF promote TREM-1 level in monocytes through the COX-2/PGE₂ pathway. a Total RNA was reverse-transcribed, and the mRNA level of COX-2 in RASF (n = 5) or OASF (n = 5) or HCSF (n = 5) was detected by qPCR. b After RASF or OASF or PTSF were cultured for 24 h with or without 10 ng/mL IL-1β stimulation, the cell culture supernatants were collected for PGE₂ ELISA. c After stimulation with recombinant PGE₂ or vehicle, TREM-1 expression in CD14⁺ monocytes was measured by flow cytometry. The left panel was the representative flow cytometric histograms, and the right panel was a statistical chart. d After CD14⁺ monocytes were co-cultured with RASF (n = 5) pre-treated with or without of Celecoxib (Cel, 100 μmol) (specific COX-2 inhibitor) for 24 h, TREM-1 level in CD14⁺ monocytes were measured using flow cytometry. The left panel was the representative flow cytometric histograms, and the right panel was a statistical chart. e After CD14⁺ monocytes co-cultured with RASF (n = 5) expressing control siRNA or COX-2 siRNA for 24 h, the expression of TREM-1 in monocytes was detected by flow cytometry. f After CD14⁺ monocytes pre-treated with antagonists of EP1–4 (GW848687, AH6809, L798106, and AH23848) were co-cultured with RASF (n = 5) for 24 h, TREM-1 expression in monocytes was detected by flow cytometry. *P < 0.05, by ANOVA followed by Bonferroni’s post hoc test (a, b, d, e, and f) and two-tailed Student’s t test (c)