RELEVANCE OF PLATELETS IN NETS-INDUCED ENDOTHELIAL DAMAGE IN HEMOLYTIC UREMIC SYNDROME

LANDONI, VERONICA I.; RODRIGUEZ-RODRIGUES, NAHUEL; CASTILLO, LUIS A.; CARESTIA, AGOSTINA; DE CAMPOS NEBEL, MARCELO; MARTIRE-GRECO, DAIANA; BIRNBERG WEISS, FEDERICO; SCHATTNER, MIRTA; SCHIERLOH, PABLO; FERNANDEZ, GABRIELA C.

Congreso; LXV Reunión Anual de la Sociedad Argentina de Inmunología 2017 - Reunión Conjunta de Sociedades de Biociencias; 2017

Hemolytic Uremic Syndrome (HUS) is the most common cause of pediatric renal failure. Linked to Gram (-) Shiga toxin-producing (Stx) infections, lipopolysaccharide (LPS) and neutrophils (PMN) can potentiate the disease. Since endothelial damage is characteristic of HUS, PMN-platelet (Plts) interaction in the context of Stx could promote netosis causing endothelial damage. We have shown that Stx2 increases netosis induced by LPS-treated Plts and endothelial cytotoxicity in vitro. The aim of this work is to study in detail this phenomenon and determine the relevance of netosis in a murine model of HUS. We determined in vitro by FACS that Stx2 stimulation of LPS-treated Plts increased the formation of PMN-Plts mixed aggregates (% CD11b+CD61+ p≤0,05) and increased the activation of both PMN (CD11b p≤0,05) and Plts (P-selectin p≤0,05). Additionally, the increased netosis promoted by Stx2 stimulation of LPS-treated Plts was dependent on the PMN-Plts-mediated P-selectin junction. In order to corroborate in vitro findings, mice administrated with LPS and Stx2 showed an increased % of PMN-Plts blood aggregates (%Gr1+CD61+ p≤0.05) in LPS+Stx2 treated mice. Also the NETs in this group were increased measured using an ELISA kit (PMN Elastase-DNA levels p≤0.05).Correlating with this, endothelial damage was higher in LPS+Stx2 treated mice (von Willebrand Factor, vWF levels in plasma p≤0.05). NETs were digested and levels of Elastase-DNA decreased correlating with vWF diminution. Finally, in order to evaluate the role of circulating Plts mice were depleted of Plts. We observed in LPS+Stx2 mice without Plts that, both netosis (Elastase-DNA levels p≤0.05) and endothelial damage levels (vWF p≤0.05) decreased compared to LPS+Stx2. These results demonstrate the relevance of LPS+Stx2 induced netosis on vascular damage and the fundamental role of Plts in this phenomenon.