Focal adhesion kinase regulates intestinal epithelial barrier function via redistribution of tight junction
Focal adhesion kinase regulates intestinal epithelial barrier function via redistribution of tight junction
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DOI：
10.1016/j.bbadis.2012.10.006
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发表时间：
2013-01-01
影响因子：
6.2
通讯作者：
Taniguchi, Takanobu
中科院分区：
文献类型：
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作者：
Ma, Yanju;Semba, Shingo;Taniguchi, Takanobu
上皮屏障功能的破坏被确定为炎症性肠病（IBD）的病理机制之一。上皮屏障由各种细胞间连接组成，其中紧密连接（TJ）是重要组成部分。然而，紧密连接的调控机制仍不清楚。在这里，我们使用特定的 FAK 抑制剂 PF-573, 228 (PF-228) 检查了粘着斑激酶 (FAK) 在 Caco-2 单层上皮屏障功能中的作用。我们发现，跨上皮阻力的降低和细胞旁通透性的增加伴随着PF-228处理对FAK自身磷酸化的抑制。此外，PF-228 抑制 Src 激活环上 Y576/577 处的 FAK 磷酸化，表明 Caco-2 单层中 FAK 的调节依赖于 Src。在乙醇诱导的屏障损伤模型中，PF-228 治疗还抑制跨上皮阻力的恢复以及 FAK 的磷酸化。在蔗糖梯度超速离心中，FAK 与 Claudin-1（TJ 复合物的一个元件）共定位，并且它们在乙醇诱导的屏障损伤后共同迁移。免疫荧光成像分析显示，在乙醇诱导的屏障损伤后的恢复过程中，PF-228 抑制 FAK 向细胞边界的重新分布和 TJ 蛋白的重新组装。最后，通过 siRNA 敲低 FAK 导致跨上皮阻力降低。这些发现表明，FAK 的激活对于通过调节 TJ 重新分布来维持和修复 Caco-2 单层细胞中的上皮屏障是必要的。 (c) 2012 Elsevier B.V. 保留所有权利。
Disruption of epithelial barrier function was identified as one of the pathologic mechanisms in inflammatory bowel diseases (IBD). Epithelial barrier consists of various intercellular junctions, in which the tight junction (TJ) is an important component. However, the regulatory mechanism of tight junction is still not clear. Here we examined the role of focal adhesion kinase (FAK) in the epithelial barrier function on Caco-2 monolayers using a specific FAK inhibitor, PF-573, 228 (PF-228). We found that the decrease of transepithelial resistance and the increase of paracellular permeability were accompanied with the inhibition of autophosphorylation of FAK by PF-228 treatment. In addition, PF-228 inhibited the FAK phosphorylation at Y576/577 on activation loop by Src, suggesting Src-dependent regulation of FAK in Caco-2 monolayers. In an ethanol-induced barrier injury model, PF-228 treatment also inhibited the recovery of transepithelial resistance as well as these phosphorylations of FAK. In a sucrose gradient ultracentrifugation, FAK co-localized with claudin-1, an element of the TJ complex, and they co-migrate after ethanol-induced barrier injury. Immunofluorescence imaging analysis revealed that PF-228 inhibited the FAK redistribution to the cell border and reassembly of TJ proteins in the recovery after ethanol-induced barrier injury. Finally, knockdown of FAK by siRNA resulted in the decrease of transepithelial resistance. These findings reveal that activation of FAK is necessary for maintaining and repairing epithelial barrier in Caco-2 cell monolayer via regulating TJ redistribution. (c) 2012 Elsevier B.V. All rights reserved.