Project description:The goal was to determine the chemotherapy-induced, mammalian cell death-dependent transcriptional response in a human commensal strain of E. coli. Murine intestinal epithelial cells were used to induce chemotherapy-driven cell death, and a human commensal strain of E. coli was used as the 'recipient' bacteria.
Project description:Epigenetic changes such as DNA methylations regulate gene expression patterns in response to environmental cues including infections. Microbial infections induced DNA methylation may play a potential role in modulating host-immune response. In the present study, we sought to determine DNA methylation changes induced by the mastitis causing Escherichia coli (E coli) in porcine mammary epithelial cells (PMEC). Two time points (3hr and 24 hr) were selected based on the specific transcriptomic changes as early and late phase immune responses. Genome-wide methylation information was obtained to identify significant differential methylation patterns in E coli infected PMEC.
Project description:Enterohemorrhagic Escherichia coli (EHEC) is a food-borne pathogen that causes diarrheal disease and the potentially lethal hemolytic uremic syndrome. Here, we used an infant rabbit model of EHEC infection that recapitulates many aspects of human intestinal disease to comprehensively assess the host colonic epithelial and lamina propria cell transcriptional responses to EHEC infection. Furthermore, comparisons of colonic pathology and intestinal transcriptomic profiles in animals infected with EHEC strains containing or lacking Shiga toxins (∆∆stx) were carried out to investigate how these potent toxins shape the host response to the pathogen. We found that Stx is required for severe, multi-focal hemorrhage and extensive apoptosis in the colon. RNA-sequencing revealed that EHEC infection elicits a robust innate immune response in the colonic epithelium that is dramatically shaped by Stx. Over 1400 genes were differentially expressed in animals infected with WT versus ∆∆stx EHEC strains. Several pathways linked to innate immune responses were dependent on Stx. Upregulated genes in the presence of toxin included cytokines IL23a and CXCL8, as well as F3, the gene encoding the coagulation initiator Tissue Factor. RNA FISH revealed that these elevated transcripts were found almost exclusively in epithelial cells, suggesting that Stx remodels the transcriptional profile of the epithelium. Collectively, these findings reveal that Stx potently modulates the innate immune response to EHEC in the intestine, and suggest that Stx drives the response to infection towards type 3 immunity.