TNFα up-regulates claudin-2 expression in epithelial HT-29/B6 cells via phosphatidylinositol-3-kinase signaling
TNFα up-regulates claudin-2 expression in epithelial HT-29/B6 cells via phosphatidylinositol-3-kinase signaling
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DOI：
10.1007/s00441-009-0751-8
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发表时间：
2009-04-01
影响因子：
3.6
通讯作者：
Schulzke, J. D.
中科院分区：
文献类型：
--
作者：
Mankertz, J.;Amasheh, M.;Schulzke, J. D.
我们的目的是表征响应于促炎细胞因子肿瘤坏死因子-α（TNF α）调节通道形成紧密连接蛋白claudin-2表达的分子机制，所述促炎细胞因子肿瘤坏死因子-α例如在活动性克罗恩病中升高。TNF α导致结肠HT-29/B6细胞的细胞旁阻力降低89%，而跨细胞阻力不变。claudin-2蛋白水平的增加，TNF α没有变化，在亚细胞紧密连接蛋白的定位显示，通过激光共聚焦扫描显微镜。增强的基因表达被确定为这种增加的来源，因为claudin-2特异性mRNA和启动子活性升高，而mRNA稳定性保持不变。特异性抑制剂和磷酸化特异性抗体显示，TNF α治疗后claudin-2的基因表达增加是由磷脂酰肌醇-3-激酶途径介导的。因此，通过TNF α上调密蛋白-2可归因于基因表达的调节，其结果是例如在慢性肠道炎症期间上皮屏障功能受到干扰。
Our aim has been to characterize the molecular mechanisms regulating the expression of the channel-forming tight-junctional protein claudin-2 in response to the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF alpha), which is elevated, for example, in active Crohn's disease. TNF alpha caused an 89% decrease of the paracellular resistance in colonic HT-29/B6 cells, whereas transcellular resistance was unaltered. The claudin-2 protein level was increased by TNF alpha without changes in subcellular tight-junctional protein localization as revealed by confocal laser scanning microscopy. Enhanced gene expression was identified as the source of this increase, since claudin-2-specific mRNA and promoter activity was elevated, whereas mRNA stability remained unaltered. Specific inhibitors and phospho-specific antibodies revealed that the increased gene expression of claudin-2 after TNF alpha treatment was mediated by the phosphatidylinositol-3-kinase pathway. Thus, the up-regulation of claudin-2 by TNF alpha is attributable to the regulation of the expression of the gene, as a result of which epithelial barrier function is disturbed, for example, during chronic intestinal inflammation.