Fig. 4
Exosomes derived from SiO2-exposed macrophages promote monocyte/macrophage migration through CCR2. (A). Transwell assay of the migration of RAW264.7 macrophages or THP-1 monocytes treated with PBS, NC-Exo, SiO2-Exo or SiO2 + GW4869-Exo. The scale bar represents 50 μm. (B-E). The expression of CCR2 in RAW264.7 macrophages or THP-1 monocytes treated with PBS, NC-Exo, SiO2-Exo or SiO2 + GW4869-Exo was analysed by RT–PCR (B-C) and western blotting (D-E). (F-G). Transwell assay of the migration of RAW264.7 macrophages or THP-1 monocytes treated with SiO2-Exo in the presence of a CCR2 antagonist (10 nM, 20 nM, 40 nM, or 100 nM). The scale bar represents 50 μm. The data are representative of three individual experiments and expressed as the mean ± SEM. The data were analysed by Student’s t test or two-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Abbreviations SiO2 = silica dust; NC-Exo = exosomes derived from cells without SiO2 exposure; SiO2-Exo = exosomes derived from SiO2-exposed macrophages; SiO2 + GW4869-Exo = exosomes derived from SiO2-exposed macrophages treated with GW4869 (10 µM); antago = antagonist