Epithelial cell spreading induced by hepatocyte growth factor influences paxillin protein synthesis and posttranslational modification
Epithelial cell spreading induced by hepatocyte growth factor influences paxillin protein synthesis and posttranslational modification
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DOI：
10.1152/ajpgi.00065.2004
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发表时间：
2004-10-01
影响因子：
4.5
通讯作者：
Nusrat, A
中科院分区：
文献类型：
--
作者：
Hopkins, AM;Bruewer, M;Nusrat, A
胃肠道中的浅表伤口通过由伤口附近释放的细胞因子如肝细胞生长因子（HGF）/分散因子促进的协调上皮细胞迁移而快速重新密封。然而，肝细胞生长因子促进生理和病理生理上皮细胞迁移的机制还不完全清楚。使用极化的T84和Caco-2肠上皮细胞的体外模型，我们报告说，肝细胞生长因子促进上皮细胞的扩展和RhoA GTdR激活的时间依赖性的方式。增强型绿色荧光蛋白标记的显性负性RhoA的诱导表达显著减弱了HGF诱导的扩散。肝细胞生长因子扩大了一个区域的部分扁平细胞后面的伤口边缘含有基础的F-肌动蛋白纤维排列在扩展的方向。同时，斑块阳性的粘着斑蛋白桩蛋白增强。肝细胞生长因子诱导桩蛋白的翻译增加，在较小程度上，β（1）-整合素。这是独立的细胞-基质粘附通过β（1）-整合素。亚细胞分级显示，在HGF刺激后，桩蛋白与含有质膜的组分的共沉降增加，而桩蛋白与β（1）整合素或肌动蛋白的共结合没有相应的增强。桩蛋白的酪氨酸磷酸化被HGF降低，并且对Src激酶抑制剂PP 2敏感。结合这些，我们认为HGF上调了一个与细胞骨架或局灶性细胞基质接触无关的游离细胞质桩蛋白池。因此，对HGF的早期扩散反应可能部分地与桩蛋白掺入动态细胞骨架/膜复合物中的可用性增加和动态细胞骨架/膜复合物内的周转有关，动态细胞骨架/膜复合物快速和短暂粘附于基质驱动迁移。
Superficial wounds in the gastrointestinal tract rapidly reseal by coordinated epithelial cell migration facilitated by cytokines such as hepatocyte growth factor (HGF)/scatter factor released in the wound vicinity. However, the mechanisms by which HGF promotes physiological and pathophysiologic epithelial migration are incompletely understood. Using in vitro models of polarized T84 and Caco-2 intestinal epithelia, we report that HGF promoted epithelial spreading and RhoA GTPase activation in a time-dependent manner. Inducible expression of enhanced green fluorescent protein-tagged dominant-negative RhoA significantly attenuated HGF-induced spreading. HGF expanded a zone of partially flattened cells behind the wound edge containing basal F-actin fibers aligned in the direction of spreading. Concomitantly, plaques positive for the focal adhesion protein paxillin were enhanced. HGF induced an increase in the translation of paxillin and, to a lesser extent, beta(1)-integrin. This was independent of cell-matrix adhesion through beta(1)-integrin. Subcellular fractionation revealed increased cosedimentation of paxillin with plasma membrane-containing fractions following HGF stimulation, without corresponding enhancements in paxillin coassociation with beta(1) integrin or actin. Tyrosine phosphorylation of paxillin was reduced by HGF and was sensitive to the Src kinase inhibitor PP2. With these taken together, we propose that HGF upregulates a free cytosolic pool of paxillin that is unaffiliated with either the cytoskeleton or focal cell-matrix contacts. Thus early spreading responses to HGF may partly relate to increased paxillin availability for incorporation into, and turnover within, dynamic cytoskeletal/membrane complexes whose rapid and transient adhesion to the matrix drives migration.