The flagella of enteropathogenic Escherichia coli mediate adherence to epithelial cells
The flagella of enteropathogenic Escherichia coli mediate adherence to epithelial cells
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DOI：
10.1046/j.1365-2958.2002.02899.x
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发表时间：
2002-04-01
影响因子：
3.6
通讯作者：
Kaper, JB
中科院分区：
文献类型：
--
作者：
Girón, JA;Torres, AG;Kaper, JB
肠致病性大肠杆菌（EPEC）利用III型蛋白分泌系统将效应分子靶向宿主细胞，导致肠粘膜消失。这种分泌装置的鞭毛III型出口系统参与鞭毛组装和运动的许多结构特征。我们在这里报告，在两个野生型EPEC菌株中构建的fliC插入突变体在培养细胞上的粘附和小菌落形成中明显受损。大肠在质粒上携带EPEC H6 fliC基因的大肠杆菌K-12菌株在HeLa细胞上显示出离散的粘附簇，尽管程度低于野生型EPEC菌株。从EPEC中纯化的鞭毛与培养的上皮细胞结合，抗鞭毛抗体阻断了几种EPEC血清型的粘附。我们确定，培养的真核细胞刺激鞭毛表达的运动和非运动EPEC。在perA（一种转录激活因子），bfpA（一种IV型菌毛蛋白），luxS（一种群体感应自诱导基因）和III型分泌基因中突变的同基因菌株在Dulbecco改良的Eagle培养基（DMEM）运动琼脂中的运动性降低，并且当与上皮细胞结合时不产生或产生很少的鞭毛。这些突变体在预处理的组织培养基中的生长恢复了运动性和产生鞭毛的能力，表明哺乳动物细胞提供的触发鞭毛产生的信号的影响。这项研究首次表明，鞭毛的EPEC直接参与这些细菌的粘附，并支持存在的两个现有的III型分泌途径的EPEC，EPEC粘附因子（EAF）质粒编码的调节器，群体感应和上皮细胞之间的分子关系。
Enteropathogenic Escherichia coli (EPEC) utilizes a type III protein secretion system to target effector molecules into the host cell leading to effacement of the intestinal mucosa. This secretion apparatus shares many structural features of the flagellar type III export system involved in flagella assembly and motility. We report here that fliC insertional mutants constructed in two wild-type EPEC strains were markedly impaired in adherence and microcolony formation on cultured cells. An E. coli K-12 strain harbouring the EPEC H6 fliC gene on a plasmid showed discrete adhering clusters on HeLa cells, albeit to less extent than the wild-type EPEC strain. Flagella purified from EPEC bound to cultured epithelial cells and antiflagella antibodies blocked adherence of several EPEC serotypes. We determined that eukaryotic cells in culture stimulate expression of flagella by motile and non-motile EPEC. Isogenic strains mutated in perA (a transcriptional activator), bfpA (a type IV pilin), luxS (a quorum-sensing autoinducer gene) and in the type III secretion genes were reduced for motility in Dulbecco's modified Eagle medium (DMEM) motility agar and produced none or few flagella when associated with epithelial cells. Growth of these mutants in preconditioned tissue culture medium restored motility and their ability to produce flagella, suggesting the influence of a signal provided by mammalian cells that triggers flagella production. This study shows for the first time that the flagella of EPEC are directly involved in the adherence of these bacteria and supports the existence of a molecular relationship between the two existing type III secretion pathways of EPEC, the EPEC adherence factor (EAF) plasmid-encoded regulator, quorum sensing and epithelial cells.