Enteropathogenic Escherichia coli dephosphorylates and dissociates occludin from intestinal epithelial tight junctions
Enteropathogenic Escherichia coli dephosphorylates and dissociates occludin from intestinal epithelial tight junctions
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DOI：
10.1046/j.1462-5822.2000.00055.x
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发表时间：
2000-08-01
影响因子：
3.4
通讯作者：
Hecht, G
中科院分区：
文献类型：
--
作者：
Simonovic, I;Rosenberg, J;Hecht, G
肠致病性大肠杆菌（EPEC）增加紧密连接通透性的一部分，通过磷酸化的20 kDa肌球蛋白轻链（MLC 20），诱导细胞骨架收缩。这种肠道病原体对特异性紧密连接（TJ）蛋白的影响尚未研究。我们研究了EPEC感染对肠上皮细胞中occludin定位和磷酸化的影响。EPEC感染后，occludin从一个主要的TJ相关的结构域的细胞内室发生了一个渐进的转变，如免疫荧光染色所示。伴随着这种形态学的变化，在磷酸化的比例，去磷酸化occludin逆转。用庆大霉素根除EPEC导致闭合蛋白定位和磷酸化正常化。丝氨酸/苏氨酸磷酸酶抑制剂，calyculin A，防止这些事件。庆大霉素治疗后，EPEC相关的跨上皮电阻（TJ屏障功能的测量）下降恢复至基线水平。非致病性E. coli K-12不能诱导这些变化。然而，用EPEC的致病岛转化K-12，赋予野生型EPEC的表型。删除特定的EPEC基因编码的蛋白质参与EPEC III型分泌显着减弱这些影响。这些研究结果表明，EPEC诱导的occludin的改变有助于与这种感染相关的病理生理学。
Enteropathogenic Escherichia coli (EPEC) increases tight junction permeability in part by phosphorylating the 20 kDa myosin light chain (MLC20) that induces cytoskeletal contraction. The impact of this enteric pathogen on specific tight junction (TJ) proteins has not been investigated. We examined the effect of EPEC infection on occludin localization and phosphorylation in intestinal epithelial cells. After infection by EPEC, a progressive shift of occludin from a primarily TJ-associated domain to an intracellular compartment occurred, as demonstrated by immunofluorescent staining. A reverse in the ratio of phosphorylated to dephosphorylated occludin accompanied this morphological change. Eradication of EPEC with gentamicin resulted in the normalization of occludin localization and phosphorylation. The serine/threonine phosphatase inhibitor, calyculin A, prevented these events. The EPEC-associated decrease in transepithelial electrical resistance, a measure of TJ barrier function, returned to baseline after gentamicin treatment. Non-pathogenic E. coli, K-12, did not induce these changes. Transformation of K-12 with the pathogenicity island of EPEC, however, conferred the phenotype of wild-type EPEC. Deletion of specific EPEC genes encoding proteins involved in EPEC type III secretion markedly attenuated these effects. These findings suggest that EPEC-induced alterations in occludin contribute to the pathophysiology associated with this infection.