Fig. 3

aBMSCs and BMSCs promoted phagocytosis of E. coli in THP-1 macrophages. THP-1 cells were incubated for 96 h with PMA to differentiate into macrophages in the presence or absence of aBMSCs/BMSCs cultured in Transwell inserts. THP-1 cells differentiated in the presence of IL-4 at 100 ng/mL for 72 h served as a M2 polarization control. THP-1 macrophages were treated with AF488-labeled E. coli for 1 h, followed by 1 min Trypan blue treatment to quench extracellular fluorescence. Cells were rinsed, detached, and subjected to flow cytometry to evaluate the phagocytic activity by counting AF 488-positive cells. a–d Representative flow cytometric density plots and histograms of THP-1 macrophages treated with PMA alone (a), PMA + IL-4 (b), PMA + aBMSCs (c), and PMA + BMSCs (d). e Quantitation of fluorescent THP-1 macrophages (AF488-positive events) in indicated treatment groups. **P < 0.01. n = 3 in each group, and aBMSCs and BMSCs were isolated from three different donors, respectively