NEUTROPHIL EXTRACELLULAR TRAPS RELEASED IN RESPONSE OF CIGARETTE SMOKE EXTRACT INCREASE THE SECRETION OF PROINFLAMMATORY CYTOKINES BY HUMAN ALVEOLAR EPITHELIAL CELLS.

FLORENCIA SABIONE; IRENE KEITELMAN; MAURICIO GUZMÁN; JEREMÍAS GALLETTI; MARIANA C FERRERO; PABLO C BALDI; NADIA TOWSTYKA; MIRTA GIORDANO; CAROLINA JANCIC; ANALÍA TREVANI

Mar del Plata

Congreso; LXIV Reunión anual de la Sociedad Argentina de Inmunología; 2016

Sociedad Argentina de Inmunología

Cigarette smoking is a major cause of chronicobstructive pulmonary disease. Gas phase of cigarette smoke (CS) can reachthe alveolarepithelium inducing the secretion of chemokines and cytokines that contributeto recruit neutrophils (PMN) into the airway lumen. In response to diversestimuli, PMN release neutrophil extracellular traps (NET) through a processcalled NETosis. Previous studies determined that CS and uric acid (UA), a majorDAMP found at high concentrations in lungs of patients with acute lung injury,can induce NETosis. The aim of this study was to determine if a short exposureto CS is able to induce NETosis, and if these NET induce proinflammatorycytokine secretion by alveolar epithelial cells, comparing their effects withthose produced by NET released in response to UA (8 mg/dl). CS extract (CSE)prepared according to a standard method from cigarettes containing anequivalent of 13.6 mg/ml tar was used at 10%. PMN were incubated with orwithout stimuli for 1h, then washed and cultured for 3 more hours at 37°C. NETwere identified by confocal microscopy by colocalization of DNA withmyeloperoxidase. Short exposure to both stimuli induced NETosis. NET releasedby 106 PMN were isolated and added to A549 epithelial cell monolayers. BothCSE- and UA-induced NET significantly increased the secretion of IL-8 and IL-6(p<0.05; n=4), and IL-1b (n=2) by A549 as compared to that induced bysupernatants from unstimulated PMN and basal conditions. These effects were notobserved with supernatants from CS-stimulated PMN pretreated with the NETosis inhibitorCL-amidine (200 μM; n=2). These findings suggest that CSE might alsopromote alveolar inflammation by triggering NETosis. Together with our previousfindings indicating similar properties of NET induced by monosodium uratecrystals, these results alsosuggest that NET exert proinflammatory effects on epithelialcells independently of the sterile stimulus that induced their release.