VIP AND CONDITIONED MEDIA FROM TROPHOBLAST CELLS INHIBIT AUTOPHAGIC PROCESSES IN NEUTROPHILS AND PROMOTE THEIR APOPTOSIS THROUGH ACTIVATION OF CAMP-PKA PATHWAY

CALO, GUILLERMINA; KEITELMAN I; SABBIONE F; VOTA, DAIANA; PAPARINI D; RAMHORST R; TREVANI AS; PEREZ LEIROS C

Congreso; Reunión Conjunta de Sociedades de Biociencias.; 2017

Trophoblast cells (Tb) interact with different maternal immune cellpopulations at early pregnancy promoting an anti-inflammatory andtolerogenic response. Neutrophils (neu) are short-lived cells andapoptosis is considered to be the major death mechanism. Autophagy and apoptosis cooperate to modulate neu survival. Failureto properly regulate neu abundance and turnover can contributeto human disease. In addition, efferocytosis of dying neu dampensproinflammatory cytokine production and reprograms macrophagesto a pro-resolution phenotype. Vasoactive Intestinal Peptide (VIP)is a pleiotropic peptide with immunomodulatory effects through itsaction on VPAC1 and VPAC2 receptors, both coupled to the activation of adenylate cyclase and protein kinase A (PKA). We havealready shown that VIP and conditioned media (CM) from humanfrst trimester Tb (Swan-71 cell line) inhibit PMA-induced NET formation, promote neutrophil apoptosis and revert the anti-apoptoticeffect of LPS. Our aim was to evaluate the effect of VIP and Tbderived factors on neu autophagy and the mechanisms involved inneu apoptosis and efferocytosis.Whole blood was obtained from healthy donors and neu purifed ona Ficoll-Paque PLUS gradient and Dextran sedimentation. We foundthat CM and VIP inhibit PMA-induced autophagy, quantifed by fluorescence intensity of LC3 puntae by confocal microscopy (p≤0.05).On the other hand, H89 a PKA inhibitor, blocks the pro-apoptoticeffect of VIP on neu apoptosis (p≤0.05), determined by fluorescencemicroscopy with ethidium bromide and acridine orange. Moreover,the release of elastase, known to prevent efferocytosis, was reduced when neu were stimulated with PMA + VIP or CM, comparedto PMA alone as evaluated by flow citometry. We conclude that VIPand Tb factors regulate autophagic and apoptotic processes in neuand suggests that they contribute to the maintenance of an anti-inflammatory microenvironment during early pregnancy