IMPACT OF NEUTROPHIL EXTRACELLULAR TRAPS NETS ON THE PHYSIOLOGY OF HUMAN EPITHELIAL CELLS

SABBIONE F; KEITELMAN I; IULA L; JANCIC C; GORI S; PODAZA E; GIORDANO M; GABELLONI ML; TREVANI A

Los Cocos, Córdoba

Congreso; LXI Reunión Anual de la Sociedad Argentina de Inmunología (SAI).; 2013

Sociedad Argentina de Inmunología

Neutrophils mediate bacterial killing by eitherphagocytosis or the release of extracellular traps (NETs).NETs are structures made of chromatin associated withspecific proteins from the granules, that contribute tothe extracellular elimination of pathogens. The airwayepithelium is constantly interacting with theenvironment, and it was found to express severalpattern recognition receptors such as the DNA receptorTLR9. When these receptors are stimulated they lead tothe production of cytokines and chemokines thatpromote inflammation and recruit phagocytes to clearthe infection. In this inflammatory context neutrophilscan transmigrate the pulmonary epithelium and releaseNET, as has been reported in pulmonary alveoli of miceinfected with S. pneumoniae. The aim of this study wasto address if NETs exert immunomudulatory effects onepithelial cells. NETs were obtained from 2 x 106/mlneutrophils isolated from peripheral blood from healthydonors cultured with MSU crystals (300 µg/ml) for 4 h at37° C. As controls, NETs were treated with micrococcalnuclease (MNase, 10 U/ml) and cytoplasms wereobtained from 2 x 106/ml neutrophils by heating at 45o Cand cooling. A549 epithelial cells at 80-90% confluencewere incubated with NETs, MNase-treated NETs,neutrophil cytoplasms or MNase for 24 h at 37o C withor without LPS (250 ng/ml). Culture supernatants werecollected and IL-6 and MCP-1 were determined byELISA. NETs or MNase-treated NETs significantlyincreased the secretion of IL-6 and MCP-1 by epithelialcells either in the absence or presence of LPS (IL-6, p