VIP promotes apoptotic cell phagocytosis by monocytes/macrophages through αvß3 integrin-thrombospondin portal formation and enhanced trophoblast migration in a model of maternal-placental interaction

PAPARINI D ; GRASSO E; CALO G; VOTA D; RAMHORST R; PEREZ LEIROS C

Buenos Aires

Congreso; Reunion Anual de la Sociedad Argentina de Inmunologia; 2015

VIP enhances apoptotic cell phagocytosis by monocyte/macrophages in an in vitro model of immune-trophoblast interactionPaparini Daniel, Grasso Esteban, Guillermina Calo, Daiana, Ramhorst, Rosanna; Perez Leiros, ClaudiaImmunopharmacology Laboratory. School of Sciences, University of Buenos Aires. IQUIBICEN-CONICET.Homeostasis maintenance at the early maternal-fetal interface requires the silent clearance of apoptotic cells by macrophages bearing an immunsosuppressant profile. VIP is a pleiotropic polypeptide synthesized by trophoblast cells that promotes an anti-inflammatory profile in monocytes (Mo) and macrophages (Ma) although its role to modulate macrophages at early pregnancy has not been elucidated yet.Objective To explore VIP effect on trophoblast-monocyte/macrophage interaction with special focus on Mo/Ma migration, phenotype and phagocytosis of apoptotic cells.Methods Mo were purified by Percoll from blood mononuclear cells of healthy women and cultured with conditioned media (CM) from a first trimester human cytotrophoblast cell line (Swan-71) (Tb) in the presence/absence of VIP (10-100 nM). Apoptotic Tb cell were induced with camptothecin and neutrophils was spontaneous. CFSE-labelled apoptotic cell phagocytosis by CD14+ cells and migration through 5um pore transwells was determined by FACs. Expression of CD39, IL-10, IL-12, TNF-α and adhesion molecules was also evaluated by FACs. Thrombospondin expression was determined by RT-PCR. Results CM from Tb cells treated for 18 h with VIP (CM-VIP) increased CD14+ cell migration to a higher extent than CM alone. Similarly, CM-VIP increased αVß3 integrin expression on macrophages and enhanced the phagocytosis of apoptotic Tb cells. In parallel, VIP treated Tb cells showed an increased expression of thrombospondin, a known ligand of αVß3 to favor apoptotic cell clearance in macrophages. CM-VIP increased CD14+IL-10+ cell frequency while diminished TNF-α positive cells. In line with this, CD14+ cell profile modulation with increased % of IL-10+CD39+ cells without changes in IL-12 and TNF-α was also induced upon co-culture with Tb in the presence of VIP. Conclusion These results support a homeostatic role of VIP at the early maternal-placental interface through modulating macrophage migration and functional profile as well as Tb cell signals that contribute to a silent clearance of apoptotic bodies.