NADPH oxidase activity controls the fate of IL-1 beta containing vesicles in human neutrophils

IULA L; KEITELMAN I; SABBIONE F; JANCIC C; TREVANI AS

Congreso; II Congreso Franco-Argentino de Inmunología.; 2015

Interleukin-1β (IL-1β) is a pro-inflammatory cytokine synthesized in the cytoplasm, after proteolytical processing, is released from cells by poorly-defined secretory pathways different from the canonical ER-Golgi route of secretion. Although an unconventional secretory autophagy mechanism has been proposed to explain IL-1 release, other reports indicated that autophagy targets IL-1β for degradation. We determined that autophagy inhibitors 3-methyadenine, Wortmannin, Bafilomycin A1 markedly reduced IL-1β secretion induced with LPS+ATP evaluated by ELISA, without affecting cell viability. In neutrophil-differentiated PLB985 cells, siRNA knockdown of ATG5, an essential component of the autophagic pathway, abolished IL-1β secretion. Stimulation with LPS+ATP showed a vesicular distribution of IL-1β co-localizing with LC3B, a marker of autophagy vesicles, by confocal microscopy (CLSM). We determined, that stimulation of autophagy by cell starvation markedly increased IL-1β and LC3B colocalization and significantly promoted IL-1β secretion (p