Department of Neurosurgery, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China.
Department of Clinical Laboratory, Tianjin First Central Hospital, Nankai University, Tianjin 300192, PR China.
Int J Med Microbiol. 2018 Oct;308(7):840-847. doi: 10.1016/j.ijmm.2018.07.010. Epub 2018 Jul 30.
Enteropathogenic Escherichia coli colonizes the human small intestine and causes severe diarrhea. Short-chain fatty acids are abundant in the intestine owing to the metabolic activity of the microflora and are important for intestinal health. Here, we found that acetate promotes the adherence of enteropathogenic E. coli O127:H6 to Caco-2 intestinal epithelial cells and its motility on semi-solid Luria-Bertani agar by activating the expression of locus of enterocyte effacement genes and flagellar genes, respectively. The effect of acetate on locus of enterocyte effacement gene expression is mediated by Ler, the master regulator of locus of enterocyte effacement genes, whereas the regulation of flagellar genes by acetate is dependent on the RNA polymerase sigma factor FliA. Conversely, formate, propionate, and butyrate had little or no effect on enteropathogenic E. coli O127:H6 adherence and motility. Finally, the acetate-mediated regulatory pathway was found to be a widespread mechanism used by a range of enteropathogenic E. coli to mediate bacterial virulence and motility. Therefore, upon entering the human small intestine, enteropathogenic E. coli may respond to the higher acetate level to enhance its virulence and motility, leading to efficient colonization of the target niche.
肠致病性大肠杆菌定植于人体小肠并引发严重腹泻。由于微生物群的代谢活动，短链脂肪酸在肠道中大量存在，对肠道健康很重要。在这里，我们发现乙酸通过激活肠上皮细胞 effacement 基因和鞭毛基因的表达，分别促进肠致病性大肠杆菌 O127:H6 与 Caco-2 肠上皮细胞的黏附和在半固体 LB 琼脂上的运动。乙酸对肠上皮细胞 effacement 基因表达的影响是由 Ler 介导的，Ler 是肠上皮细胞 effacement 基因的主要调节因子，而乙酸对鞭毛基因的调节依赖于 RNA 聚合酶 sigma 因子 FliA。相反，甲酸盐、丙酸盐和丁酸盐对肠致病性大肠杆菌 O127:H6 的黏附和运动几乎没有影响或没有影响。最后，发现乙酸介导的调控途径是多种肠致病性大肠杆菌用来介导细菌毒力和运动的广泛机制。因此，当进入人体小肠时，肠致病性大肠杆菌可能会对更高的乙酸水平做出反应，以增强其毒力和运动能力，从而有效地定植于目标生态位。
