Differential effects of Escherichia coli Shiga type 2 and Subtilase toxins on proinflammatory cytokines and chemokines resealed by human renal cells.

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

Mar del Plata

Congreso; LXI Reunión Anual de la Sociedad Argentina de Investigación Clínica, LXIV Reunión Anual de la Sociedad Argentina de Inmunología y XLVIII Reunión Anual de la Sociedad Argentina de Farmacología Experimental.; 2016

Sociedad Argentina de Investigación Clínica

Post diarrhea hemolytic uremic syndrome (HUS), a compli-cation of Shiga toxin (Stx)-producing E. coli (STEC) infection,is the most common cause of acute renal failure in children inArgentina. Renal damage is mainly attributed to Stx, being Stx2epidemiologically more relevant than Stx1. Subtilase (SubAB) isa cytotoxin produced by STEC isolated from cases of childhooddiarrhea. Therefore, it is proposed that SubAB may contributeto HUS pathogenesis. Previously, we demonstrated that Stx2and SubAB caused cell viability decrease on primary cultures ofhuman glomerular endothelial cells (HGEC) and human tubularepithelial cell line (HK-2) after 24 h of treatment, only at hightoxins concentrations (Stx2: 1-10 ng/ml and SubAB: 100-1000ng/ml). In this work, we have evaluated the response of selectedpro-inflammatory mediators, after treatment of HGEC and HK-2with Stx2 or SubAB. Cells were incubated with Stx2 (0.001 - 10ng/ml) or SubAB (0.1 - 1000 ng/ml) for 24 h. Cultures supernatantwere collected and IL-6, IL-8 and TNF-α were quantified by ELISA.TNF-α biological activity was evaluated by a cytotoxicity assay onL929 cell line. SubAB caused a decrease in IL-6, IL-8 and TNF-αreleased by both, HGEC and HK-2 and in a dose-dependent man-ner. On the contrary, Stx2 (0.01 and 0.1 ng/ml) increased thesesoluble mediators released by HGEC. TNF-α α, IL-8 and IL-6 wereup regulated 3.3-fold, 0.4-fold and 0.3-fold, respectively, relativeto those in untreated control cells. TNF-α biologically active wasfound by the decrease of L929 cell viability with supernatants ofHGEC treated with 0.01 and 0.1 ng/ml Stx2 (p< 0.05, n=6). Stx2did not cause a significant modulation on the release of IL-6, IL-8and TNF-α by HK-2. These results suggest that toxins could havedifferent effects on the inflammatory responses triggered in the kidney. Such interplay may have important consequences for thepathogenesis of disease during infection with STEC strains thatproduce both toxins.