INVOLVEMENT OF NEUTROPHIL ELASTASE IN EFFECTS INDUCED BY SHIGA TOXIN TYPE 2 IN VITRO AND IN VIVO

SOSA F; BERNAL A; SABBIONE F; FERNÁNDEZ BRANDO R; TREVANI A; PALERMO M; RAMOS MV

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

Hemolytic Uremic Syndrome (HUS), a vascular disease that resultsin renal failure is caused by Shiga toxin (Stx)-producing E. coli. BesidesStx, inflammation caused by neutrophils (PMN) is needed forHUS. PMN release Neutrophil Extracellular Traps (NETs), involved in many diseases. We showed Stx2 induces NETosis in PMN andan increase of circulating free DNA in mice. Our aim was to studyif neutrophil elastase (NE), an enzyme associated to NETs, is involvedin NETosis and inflammation triggered by Stx2 in PMN; andto evaluate if there is an increase in NE in a murine model of HUSas a first approach to studying its involvement in the disease. PMNwere incubated with medium (Basal), Stx2 (0.1 μg/mL) alone or withan NE inhibitor, Sivelestat (Siv, 10 μM). After 4 h, DNA and NE activitywere measured in supernatants by fluorescence and absorbancerespectively. IL-8 secretion, an inflammatory cytokine, wasmeasured by ELISA. For in vivo assays, BALB/c mice inoculatedwith saline (Basal), Stx2 (1 ng/kg) or Stx+DNAse (300 U) were bledat day 3. After incubation with Stx2, we found an increase in DNAlevels (μg/mL) (Median(IQR)= Basal:0.12(0.09-0.16); Stx:0.27(0.22-0.43)*; Stx+Siv:0.14(0.13-0.16);*p