Interferon-γ and tumor necrosis factor-α synergize to induce intestinal epithelial barrier dysfunction by up-regulating myosin light chain kinase expression
Interferon-γ and tumor necrosis factor-α synergize to induce intestinal epithelial barrier dysfunction by up-regulating myosin light chain kinase expression
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DOI：
10.1016/s0002-9440(10)62264-x
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发表时间：
2005-02-01
影响因子：
6
通讯作者：
Turner, JR
中科院分区：
文献类型：
--
作者：
Wang, FJ;Graham, WV;Turner, JR
许多肠道疾病的特征是免疫细胞激活和上皮屏障功能受损。我们已经证明，细胞因子处理上皮单层增加了肌球蛋白H调节战斗链(MLC磷酸化)，并降低了屏障功能，这些都被MLC激酶(MLCK)抑制而逆转。本研究的目的是确定干扰素(干扰素)-γ和肿瘤坏死因子(肿瘤坏死因子)-α调节MLC磷酸化和破坏上皮屏障功能的机制。我们开发了一个模型，在该模型中，屏障功能障碍需要两种细胞因子。在干扰素-γ诱导的Caco-2单层中加入肿瘤坏死因子-α，也可引起屏障功能障碍，但不能作为对照。经干扰素-α诱导的单层细胞经肿瘤坏死因子-α处理后，MLCK的表达和MLC的磷酸化均增加，提示MLCK是一种可诱导的蛋白。这些效应不是由核因子-kappaB介导的。然而，当剂量低于抑制核因子-kappaB所需的剂量时，柳氮磺胺吡啶能够阻止肿瘤坏死因子-α诱导的屏障功能障碍、MLCK上调和MLC磷酸化。小剂量柳氮磺胺吡啶也可阻止由肿瘤坏死因子-α引起的形态上明显的紧密连接断裂。这些数据表明，干扰素-γ可通过MLCK上调和MLC磷酸化破坏紧密连接的形态和屏障功能，从而启动肠上皮单层对肿瘤坏死因子-α的反应。这些肿瘤坏死因子-α诱导的事件可以被临床相关药物柳氮磺吡啶预防。
Numerous intestinal diseases are characterized by immune cell activation and compromised epithelial barrier function. We have shown that cytokine treatment of epithelial monolayers increases myosin H regulatory fight chain (MLC phosphorylation and decreases barrier function and that these are both reversed by MLC kinase (MLCK) inhibition. The aim of this study was to determine the mechanisms by which interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha regulate MLC phosphorylation and disrupt epithelial barrier function. We developed a model in which both cytokines were required for barrier dysfunction. Barrier dysfunction was also induced by TNF-alpha addition to IFN-gamma-primed, but not control, Caco-2 monolayers. TNF-alpha treatment of IFN-gamma-primed monolayers caused increases in both MLCK expression and MLC phosphorylation, suggesting that MLCK is a TNF-alpha-inducible protein. These effects of TNF-alpha were not mediated by nuclear factor-kappaB. However, at doses below those needed for nuclear factor-kappaB inhibition, sulfasalazine was able to prevent TNF-alpha-induced barrier dysfunction, MLCK up-regulation, and MLC phosphorylation. Low-dose sulfasalazine also prevented morphologically evident tight junction disruption induced by TNF-a. These data show that IFN-gamma can prime intestinal epithelial monolayers to respond to TNF-alpha by disrupting tight junction morphology and barrier function via MLCK up-regulation and MLC phosphorylation. These TNF-alpha-induced events can be prevented by the clinically relevant drug sulfasalazine.