Type 1 pili-mediated adherence of Escherichia coli strain LF82 isolated from Crohn's disease is involved in bacterial invasion of intestinal epithelial cells
Type 1 pili-mediated adherence of Escherichia coli strain LF82 isolated from Crohn's disease is involved in bacterial invasion of intestinal epithelial cells
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DOI：
10.1046/j.1365-2958.2001.02315.x
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发表时间：
2001-03-01
影响因子：
3.6
通讯作者：
Darfeuille-Michaud, A
中科院分区：
文献类型：
--
作者：
Boudeau, J;Barnich, N;Darfeuille-Michaud, A
我们之前描述了大肠杆菌菌株LF82的侵袭能力，该菌株是从克罗恩病患者的回肠活检中分离出来的。在本研究中，我们通过TnphoA插入诱变来鉴定参与LF82侵袭肠上皮细胞的基因。大多数非侵入性突变体在1型毛编码操纵子内具有插入突变。两个非侵入性的膜突变体，在fimI和fimF基因中有一个插入，仍然粘附，但在与上皮细胞接触的部位失去了诱导宿主细胞膜伸长的能力。从大肠杆菌K-12中克隆的膜操纵子的易位互补实验恢复了入侵能力和诱导宿主细胞膜伸长的能力。克隆的LF82或K-12膜操纵子在非侵袭性实验室菌株JM109中的表达不具有侵袭性。因此，这些发现表明：(i) 1型毛毛介导的粘附参与了lf82诱导的宿主细胞信号传导的扰动，导致了膜的延长；（ii） 1型菌群介导的膜伸长诱导需要天然轴；（iii）这种活跃现象是侵入性过程建立的关键步骤；（iv） 1型菌毛本身不足以引发细菌内化。
We previously characterized the invasive ability of Escherichia coli strain LF82, isolated from an ileal biopsy of a patient with Crohn's disease. In the present study, we performed TnphoA insertion mutagenesis to identify genes involved in LF82 invasion of intestinal epithelial cells. Most of the non-invasive mutants had an insertion mutation within the type 1 pili-encoding operon. Two non-invasive fim mutants, which harboured an insertion within the fimI and fimF genes, still adhered but had lost the ability to induce host cell membrane elongations at the sites of contact with the epithelial cells. Transcomplementation experiments with a fim operon cloned from E. coli K-12 restored both invasive ability and the ability to induce host cell membrane elongations. Expression of the cloned LF82 or K-12 fim operon into the non-invasive laboratory strain JM109 did not confer invasive properties. Thus, these findings showed that: (i) type 1 pili-mediated adherence is involved in LF82-induced perturbation of host cell signalling responsible for membrane elongations; (ii) native shafts are required for type 1 pilus-mediated induction of membrane elongations; (iii) this active phenomenon is a key step in the establishment of the invasive process; and (iv) type 1 pili alone are not sufficient to trigger bacterial internalization.