Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina.
Laboratorio de Inmunidad Innata, Instituto de Medicina Experimental (IMEX-CONICET), Academia Nacional de Medicina, Buenos Aires 1425, Argentina.
Toxins (Basel). 2019 Nov 7;11(11):648. doi: 10.3390/toxins11110648.
Hemolytic uremic syndrome (HUS) is a consequence of Shiga toxin (Stx)-producing Escherichia coli (STEC) infection and is the most frequent cause of acute renal failure (ARF) in children. Subtilase cytotoxin (SubAB) has also been associated with HUS pathogenesis. We previously reported that Stx2 and SubAB cause different effects on co-cultures of human renal microvascular endothelial cells (HGEC) and human proximal tubular epithelial cells (HK-2) relative to HGEC and HK-2 monocultures. In this work we have analyzed the secretion of pro-inflammatory cytokines by co-cultures compared to monocultures exposed or not to Stx2, SubAB, and Stx2+SubAB. Under basal conditions, IL-6, IL-8 and TNF-α secretion was different between monocultures and co-cultures. After toxin treatments, high concentrations of Stx2 and SubAB decreased cytokine secretion by HGEC monocultures, but in contrast, low toxin concentrations increased their release. Toxins did not modulate the cytokine secretion by HK-2 monocultures, but increased their release in the HK-2 co-culture compartment. In addition, HK-2 monocultures were stimulated to release IL-8 after incubation with HGEC conditioned media. Finally, Stx2 and SubAB were detected in HGEC and HK-2 cells from the co-cultures. This work describes, for the first time, the inflammatory responses induced by Stx2 and SubAB, in a crosstalk model of renal endothelial and epithelial cells.
溶血尿毒综合征（HUS）是产志贺毒素（Stx）大肠杆菌（STEC）感染的后果，也是儿童急性肾衰竭（ARF）最常见的原因。枯草杆菌蛋白酶细胞毒素（SubAB）也与 HUS 的发病机制有关。我们之前报道过，Stx2 和 SubAB 对人肾微血管内皮细胞（HGEC）和人近端肾小管上皮细胞（HK-2）共培养物的影响与 HGEC 和 HK-2 单培养物不同。在这项工作中，我们分析了共培养物与单培养物相比在暴露于 Stx2、SubAB 和 Stx2+SubAB 时促炎细胞因子的分泌情况。在基础条件下，单核培养物和共培养物之间的 IL-6、IL-8 和 TNF-α 分泌存在差异。在毒素处理后，高浓度的 Stx2 和 SubAB 降低了 HGEC 单核培养物细胞因子的分泌，但相反，低浓度的毒素增加了它们的释放。毒素对 HK-2 单核培养物细胞因子的分泌没有调节作用，但增加了它们在 HK-2 共培养物隔室中的释放。此外，用 HGEC 条件培养基孵育后，HK-2 单核培养物被刺激释放 IL-8。最后，在共培养物的 HGEC 和 HK-2 细胞中检测到了 Stx2 和 SubAB。本研究首次描述了 Stx2 和 SubAB 在肾内皮和上皮细胞的串扰模型中诱导的炎症反应。
