Fig. 6

Effect of MSC-Exo on macrophage polarization is related to TRAF1. RAW 264.7 cells were stimulated by LPS for 12 h, followed by the treatment of MSC-Exo (20 μg/ml) for 24 h. Samples from LPS group and MSC-Exo group were collected for proteomics. a Heat map of significantly differential expression proteins in LPS+MSC-Exo group compared with LPS group. b Volcano plot of significantly differential expression proteins in LPS+MSC-Exo group compared with LPS group (vertical dotted lines, fold change > 1.5-fold; horizontal dotted line, p < 0.05; blue point, TRAF1). (c) Top 10 of signaling transduction of KEGG pathway enrichment analysis. d The expression level of TRAF1 was detected by Western blotting and quantified by ImagJ. β-actin was used as internal reference (^#p < 0.05, ^##p < 0.01, ^###p < 0.001 vs. the control group; *p < 0.05, **p < 0.01, ***p < 0.001 vs. the LPS group). (e) RAW 264.7 cells were transfected with TRAF1 siRNA or NC siRNA. The knockdown effect of siRNA on TRAF1 was detected by Western blotting. β-actin was used as internal reference (*p < 0.05, **p < 0.01, ***p < 0.001 vs. the NC siRNA group). (f) The expression levels of iNOS and Arg1 were detected using Western blotting and quantified using ImagJ. β-actin was used as internal reference (^#p < 0.05, ^##p < 0.01, ^###p < 0.001 vs. the NC siRNA group; *p < 0.05, **p < 0.01, ***p < 0.001 vs. the LPS+NC siRNA group.) Data are presented as the mean ± SEM (n = 3). g TRAF1 overexpression transfection of RAW 264.7 cells. The expression level of TRAF1 was detected using Western blotting and quantified by ImagJ. β-actin was used as internal reference (*p < 0.05, **p < 0.01, ***p < 0.001 vs. the vehicle group). h After TRAF1 overexpression transfection, macrophages were stimulated with LPS for 12 h, followed by treatment with MSC-Exo for 24 h. The protein levels of iNOS and Arg1 were measured by Western blotting and quantified by ImageJ software. Data are presented as the mean ± SEM (n = 3) (^#p < 0.05, ^##p < 0.01, ^###p < 0.001 vs. the vehicle group; *p < 0.05, **p < 0.01, ***p < 0.001 vs. the vehicle+LPS group; ^&p < 0.05, ^&&p < 0.01, ^&&&p < 0.001 vs. the TRAF1 group)