CROSS-REGULATION BETWEEN SERINE PROTEASES AND CASPASE-1 CONTROL PRO-IL-1 BETA PROCESSING BY HUMAN NEUTROPHILS

KEITELMAN I; SHIROMIZU, CM; VERA AGUILA D; PIZZANO M; VEREERTBRUGGHEN A; GALLETTI J; SABBIONE F; TREVANI AS

Congreso; Third French-Argentine Immunology Congress ? Reunión Anual Sociedades de Biociencias; 2022

Neutrophils (N) contribute to the inflammatory response by releasingInterleukin-1 beta (IL-1β), a cytokine that is synthesized in the cytosolas a precursor (pro-IL-1β) that is usually processed to an activeisoform by caspase-1 (C1). We previously determined that humanN secrete IL-1β and that both C1 and the neutrophil serine protease(NSP) are necessary for IL-1β secretion. Other studies showed thatC1 allows the NSP elastase to exit azurophil granules to the cytosol.To evaluate the contribution of each of these enzymes to pro-IL-1βprocessing, we stimulated purified human N with LPS and 2 h laterwith ATP (inflammasome activator). Before or after the addition ofATP, we treated them or not with AEBSF (NSP inhibitor), VX765(C1/-4 inhibitor) or both inhibitors together at different time points.After 5 h we determined pro-IL-1β processing by evaluating the totallevel (intra+extra-cellular) of mature IL-1β by ELISA. The additionof VX765 until 10 min post ATP stimulation led to a marked IL-1βprocessing reduction (60% p