Exosomes from LPS treated mesenchymal stem cells regulate proportion of Ly6C monocyte population / 中国药理学通报

ABSTRACT

Aim To determine the effect of exosomes from lipopolysaccharide-treated human bone marrow mesenchymal stem cells on proportion of Ly6Chigh and Ly6Clow monocytes/macrophages in inflammatory micro- environment. Methods BMSCs were obtained by gra-dient centrifugation, identified and then treated with li-popolysaccharide for 48 h. The exosomes were purified from conditional medium with or without LPS treatment and identified by CD63 protein using Western blot and transmission electron microscope. The diameters and concentration were detected by Nanoparticle Trafficking Analysis ( NTA ) . The monocytes/macrophages were sorted from bone marrow of the mice by magnetic beads. Cells were co-cultured with exosomes for 24 hours, and then treated with LPS for 48 hours. The proportion of Ly6C monocytes/macrophages was detec-ted by flow cytometry. Inflammatory cytokines in cell supernatant were investigated using ELISA. Results BMSCs surface markers CD44, CD90 were positively detected, but CD34, CD45 were not expressed. BM-SCs presented adipogenic differentiation ability. Exo-somes were positively expressing CD63 protein, and NTA showed that the diameters of exosomes were up to (82.4 ± 3.7 ) nm. BMSCs stimulated by LPS pro- duced more exosomes ( P < 0.01 ) . Exosomes from BMSCs with or without LPS treatment could increase the ratio of Ly6Chigh monocytes (P<0.01) and down-regulate the ratio of Ly6Chigh macrophages (P<0.05), and the effect of LPS treated-exosomes was more signif-icant than untreated-exosomes (P<0.05). Moreover, the concentration of IL-6 was also elevated under exo-somes treatment ( P <0.05 ) . Conclusions Human bone marrow mesenchymal stem cells-derived exosomes contribute to the regulation of Ly6Chigh monocytes/mac-rophages, indicating that they could be involved in the therapeutic treatment of inflammatory diseases.