Differential effects of Escherichia coli Shiga type 2 and Subtilase toxins on pro-inflammatory cytokines and chemokines released by human renal cells.

CAROLINA JANCIC; ROMINA SOLEDAD ALVAREZ; CRISTINA IBARRA; NADIA YASMÍN TOWSTYKA; MARÍA MARTA AMARAL

Mar del Plata

Congreso; LXI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC) LXIV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI) XLVIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE FARMACOLOGÍA EXPERIMENTAL (SAFE) VII REUNIÓN ANUAL DE LA SOCIEDAD; 2016

SAIC, SAI, SAFE, NANOMEDAR, AACYTAL

Post diarrhea hemolytic uremic syndrome (HUS), a complication of Shiga toxin (Stx)-producing E. coli (STEC) infection, is the most common cause of acute renal failure in children in Argentina. Renal damage is mainly attributed to Stx, being Stx2 epidemiologically more relevant than Stx1. Subtilase (SubAB) is a cytotoxin produced by STEC isolated from cases of childhood diarrhea. Therefore, it is proposed that SubAB may contribute to HUS pathogenesis. Previously, we demonstrated that Stx2 and SubAB caused cell viability decrease on primary cultures of human glomerular endothelial cells (HGEC) and human tubular epithelial cell line (HK-2) after 24 h of treatment, only at high toxins concentrations (Stx2: 1-10 ng/ml and SubAB: 100-1000 ng/ml). In this work, we have evaluated the response of selected pro-inflammatory mediators, after treatment of HGEC and HK-2 with Stx2 or SubAB. Cells were incubated with Stx2 (0.001 - 10 ng/ml) or SubAB (0.1 - 1000 ng/ml) for 24 h. Cultures supernatant were collected and IL-6, IL-8 and TNF-α were quantified by ELISA. TNF-α biological activity was evaluated by a cytotoxicity assay on L929 cell line. SubAB caused a decrease in IL-6, IL-8 and TNF-α released by both, HGEC and HK-2 and in a dose-dependent manner. On the contrary, Stx2 (0.01 and 0.1 ng/ml) increased these soluble mediators released by HGEC. TNF-α, IL-8 and IL-6 were up regulated 3.3-fold, 0.4-fold and 0.3-fold, respectively, relative to those in untreated control cells. TNF-α biologically active was found by the decrease of L929 cell viability with supernatants of HGEC treated with 0.01 and 0.1 ng/ml Stx2 (p< 0.05, n=6). Stx2 did not cause a significant modulation on the release of IL-6, IL-8 and TNF-α by HK-2. These results suggest that toxins could have different effects on the inflammatory responses triggered in the kidney. Such interplay may have important consequences for the pathogenesis of disease during infection with STEC strains that produce both toxins.