OBJECTIVETo study the influence of human plasma exosomes-like vesicles on the regulatory function of macrophages.

METHODSThe exosomes-like vesicles were purified from healthy donors plasma with a series of high-speed centrifugation and ultrafiltration. Macrophages were derived from cultured human blood monocytes. The molecular markers of macrophages were assayed by FACS. After cultured with exosomes-like vesicles, the changes of macrophages cytoplasma Ca(2+), and related genes and proteins were assayed by FACS, RT-PCR and Western Blot, respectively.

RESULTSAfter cultured with exosomes-like vesicles, mean fluorescent intensity (MFI) of macrophages cytoplasma Ca(2+) was increased. The vesicles enhanced macrophages to express cytokines genes, the expression of IL-1β and TNF-α genes being increased by 0.85 and 1.69 times respectively at 2 h, and that of IL-6 gene 3.7 times compared with the control at 8 h. However, the vesicles inhibited the expression of macrophages IL-10 gene, had no influence on the Frizzled5 receptor expression and could induce CaMKII phosphorylation.

CONCLUSIONSExosomes-like vesicles can up-regulat macrophages expression of inflammatory cytokines genes, and increase the secretion of inflammatory cytokines by activating the Wnt5A-Ca(2+) signaling pathway.