RNAseq study to get insights into opposing susceptibility of the Shiga toxin sensitive ACHN and Stx-refractory Caki-2 cells.. RNAseq of human kidney epithelial cells exposed to Shiga toxin

Endothelial cells of human kidneys and the brain are the main targets of Shiga toxins (Stxs) produced by enterohemorrhagic Escherichia coli (EHEC). However, recent studies revealed that renal epithelial cells are susceptible to the cytotoxic action of Stx as well and may contribute to the hemolytic uremic syndrome (HUS). The aim of this study was to figure out the difference in transcriptomic response to Stx2a of toxin sensitive (ACHN) and toxin resistant (Caki-2) human kidney epithelial cells and to verify results with an RNA interference (RNAi) approach. We exposed human kidney epithelial cells to Stx2a (4 h and 8 h) and subsequently sequenced the isolated RNA (RNAseq). Comparative transcriptomic analysis was performed using DESeq2 package (R/Bioconductor). We identified two kidney epithelial cell lines with striking difference in sensitivity towards Stx2a. Interestingly, they exhibited similar glycosphingolipid (GSL) patterns and microdomain association of the Stx receptor GSLs globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer). Employing a comparative transcriptomics approach, we found that Stx-sensitive and Stx-resistant cells differed in gene expression both upon Stx2a treatment and under control conditions. Moreover, Stx2a exerted a more pronounced response towards toxin sensitive than to toxin resistant cells. We could show that the most differentially expressed genes are involved in the secretion of pro-inflammatory cytokines and retrograde trafficking of Stx. We were able to decrease the cytotoxic action of Stx2a on toxin sensitive cells by implementing an RNAi approach. Our study provides better understanding of Stx-mediated cytotoxicity and may help in search of novel targets for therapeutic options to combat EHEC infections.