Trophoblast-derived exosomes mediate monocyte recruitment and differentiation.

Introduction: trophoblast cells have been demonstrated to regulate monocyte migration and differentiation, leading to pro-inflammatory profiles. Because trophoblast cells release exosomes with immunoregulatory properties, trophoblast-derived exosomes are proposed to 'educate' monocytes, creating a pro-inflammatory environment.

Method Of Study: exosomes were isolated from conditioned media of Swan71 cells by ultrafiltration and ultracentrifugation. Exosome-induced migration was assessed using a two-chamber system. Cytokine profiles were defined using cytokine arrays, and mRNA levels of affected cytokines were examined by qRT-PCR and ELISA.

Results: within 20 min, 8-10% of monocytes took up labeled exosomes isolated from Swan71 cells. Trophoblast-derived exosomes increased monocyte migration in a dose-dependent manner and produced significant increases in production of interleukin (IL)-1β, IL-6, Serpin-E1, granulocyte colony-stimulating factor, granulocyte/monocyte colony-stimulating factor, and tumor necrosis factor-α.

Conclusion: this study presents the initial demonstration that trophoblast-derived exosomes are capable of recruiting and 'educating' monocytes to produce pro-inflammatory cytokine/chemokine profiles in a cell-contact-independent manner.