Prokaryotic RNA activates endothelial cells and modulates their interaction with human neutrophils

CASTILLO L; LANDONI V.I; MARTIRE-GRECO, DAIANA; FERNÁNDEZ G C; RODRIGUEZ-RODRIGUES N; BIRNBERG-WEISS F

Cancun

Congreso; ALAI 2018; 2018

ALAI

Polymorphonuclear neutrophils (PMN) are the first cellular line of antibacterial host defense. Previous results obtained in our laboratory show that live but not dead bacteria are able to induce a strong PMN responses, suggesting that bacterial determinants associated with viability are necessary to trigger PMN activation. In this regard, we have demonstrated that prokaryotic RNA (pRNA), present only in live bacteria, is capable of triggering PMN activation and the generation of bactericidal responses, such as the generation of reactive oxygen species and NETs formation. Because PMN adhesion and migration is tightly regulated by endothelial cells through the increase in the expression of adhesion molecules and the secretion of chemokines, in this work our objective was to determine if pRNA can directly activate the endothelium and modulate the interaction with PMN. The ability of pRNA to activate the endothelium was evaluated using a human microvascular endothelial cell line (HMEC-1), or a primary culture of human umbilical vein endothelial cells (HUVEC). In all experiments, both endothelial cells were stimulated with RNA (1 µg/ml) extracted from E. coli (pRNA) or from human eukaryotic mononuclear cells (eRNA), or left untreated, for 24 hs. The expression of ICAM-1 (a surface glycoprotein that binds to the integrin CD11b present in PMN), measured as the mean fluorescence intensity (MFI) by flow cytometry was increased in pRNA-treated cells compared to the other groups (p