Lipid rafts mediate internalization of β1-integrin in migrating intestinal epithelial cells
Lipid rafts mediate internalization of β1-integrin in migrating intestinal epithelial cells
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DOI：
10.1152/ajpgi.00082.2008
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发表时间：
2008-11-01
影响因子：
4.5
通讯作者：
Nusrat, Asma
中科院分区：
文献类型：
--
作者：
Vassilieva, Elena V.;Gerner-Smidt, Kirsten;Nusrat, Asma
肠粘膜炎症与通过肠上皮细胞（IEC）的迁移而快速重新密封的上皮伤口相关。细胞迁移涉及细胞-基质粘附/去粘附的循环，其由基于整合素的粘着斑的动态转换（组装和分解）介导。整合素的内吞作用对于运动细胞的脱粘附似乎是至关重要的。然而，整合素内化的机制，在重塑局灶性粘连迁移IEC不清楚。本研究旨在确定迁移模型IEC中介导β（1）-整合素内化的内吞途径。我们观察到，在SK-CO 15和T84结肠上皮细胞中，β（1）-整联蛋白以动力蛋白依赖性方式内化。网格蛋白介导的内吞作用或巨胞饮作用的药理学抑制和小干扰RNA（siRNA）介导的网格蛋白敲低不能阻止β（1）-整联蛋白内化。然而，β（1）-整联蛋白内化抑制胆固醇提取后，过表达的脂筏蛋白，小窝蛋白-1。此外，内化的β（1）-整联蛋白与脂筏标记霍乱毒素共定位，并且siRNA介导的小窝蛋白-1和flotillin-1/2的敲低增加β（1）-整联蛋白的内吞作用。我们的数据表明，在迁移性IEC中，β（1）-整合素通过动力蛋白依赖性脂筏介导的途径内化。这种内吞作用可能对基于整合素的细胞-基质粘附的分解很重要，因此在调节IEC迁移和伤口闭合中很重要。
Intestinal mucosal inflammation is associated with epithelial wounds that rapidly reseal by migration of intestinal epithelial cells (IECs). Cell migration involves cycles of cell-matrix adhesion/deadhesion that is mediated by dynamic turnover (assembly and disassembly) of integrin-based focal adhesions. Integrin endocytosis appears to be critical for deadhesion of motile cells. However, mechanisms of integrin internalization during remodeling of focal adhesions of migrating IECs are not understood. This study was designed to define the endocytic pathway that mediates internalization of beta(1)-integrin in migrating model IECs. We observed that, in SK-CO15 and T84 colonic epithelial cells, beta(1)-integrin is internalized in a dynamin-dependent manner. Pharmacological inhibition of clathrin-mediated endocytosis or macropinocytosis and small-interfering RNA (siRNA)mediated knock down of clathrin did not prevent beta(1)-integrin internalization. However, beta(1)-integrin internalization was inhibited following cholesterol extraction and after overexpression of lipid raft protein, caveolin-1. Furthermore, internalized beta(1)-integrin colocalized with the lipid rafts marker cholera toxin, and siRNA-mediated knockdown of caveolin-1 and flotillin-1/2 increased beta(1)-integrin endocytosis. Our data suggest that, in migrating IEC, beta(1)-integrin is internalized via a dynamin-dependent lipid raft-mediated pathway. Such endocytosis is likely to be important for disassembly of integrin-based cell-matrix adhesions and therefore in regulating IEC migration and wound closure.