Fig. 4
Effects of propionate on tumor-like phenotypes of RA-FLSs in vitro. a Viability of RA-FLSs after treatment with vehicle (PBS) or different concentrations (0.25, 0.50 and 1.00 mmol/L) of propionate for 6 days, as detected by CCK-8 assay. b Colony formation of RA-FLSs after treatment with vehicle (PBS) or different concentrations of propionate for 7 days. Left, colony formation images; right, quantification of the colony formation images. c Migration and invasion of RA-FLSs in the presence or absence of propionate for 24 h, as detected by transwell assays. Left, migration and invasion images; right, quantification of the migration and invasion images. d Wound healing assay for RA-FLSs in the presence or absence of propionate for 24 h. Left, wound healing images; right, quantification of the wound healing images. e Apoptosis of RA-FLSs after treatment with vehicle (PBS) or different concentrations of propionate, as detected by an Annexin V-FITC/PI double staining assay. Relative mRNA expression of inflammation-related genes (MYD88, NFκB, ICAM, PTPN2 and TLR3) (f), chemokines and inflammatory cytokines (CXCL11, TNFα, CCL2, IL-6 and CXCL8) (g) and migration- and invasion-related genes (MMP13, PDGFR and MMP1) (h) in RA-FLSs after treatment with vehicle (PBS) or propionate for 48 h. Graphs represented means ± SEM and statistical significance was calculated by two-way ANOVA (a), Kruskal–Wallis H test (b–d) and Student’s t test (f–h). Experiments were performed in triplicate and repeated three times. *P < 0.05, **P < 0.01, ***P < 0.001 and ****P < 0.000 1
