Signaling pathways induced by serine proteases to increase intestinal epithelial barrier function.
Signaling pathways induced by serine proteases to increase intestinal epithelial barrier function.
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DOI：
10.1371/journal.pone.0180259
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
MacNaughton WK
中科院分区：
文献类型：
--
作者：
Lahey KA;Ronaghan NJ;Shang J;Dion SP;Désilets A;Leduc R;MacNaughton WK
胃肠道屏障功能的改变被认为是炎症性肠病克罗恩病和溃疡性结肠炎的原因。我们实验室先前的工作表明，肠上皮细胞系顶端暴露于丝氨酸蛋白酶导致跨上皮电阻（TER）增加。然而，这种反应的基本机制尚不清楚。我们的目的是确定蛋白水解活性的要求，表皮生长因子受体（EGFR）的激活，和下游的细胞内信号在启动和维持增强的屏障功能后，蛋白酶处理犬肠上皮细胞系（SCBN）。我们还研究了肌球蛋白调节轻链磷酸化对丝氨酸蛋白酶诱导的TER增加的作用。发现丝氨酸蛋白酶胰蛋白酶和间质蛋白酶的蛋白水解活性是启动和维持蛋白酶介导的TER增加所必需的。我们还表明，MMP-独立的EGFR激活是必不可少的蛋白酶反应的持续阶段，Src激酶可能介导EGFR的反式激活。PI 3-K和ERK 1/2信号传导在蛋白酶刺激后TER达到最大增加中是重要的;然而，它们的上游激活剂尚未确定。CK 2抑制阻止了由丝氨酸蛋白酶诱导的TER增加。缓激肽B（2）受体不参与丝氨酸蛋白酶引起的TER变化，胰蛋白酶或间质蛋白酶处理后未观察到MLC磷酸化的变化。总之，我们的数据显示，在蛋白酶介导的肠上皮细胞屏障增强中，需要持续的蛋白水解活性、EGFR反式激活以及下游PI 3-K、ERK 1/2和CK 2信号传导。蛋白酶介导屏障功能增强的途径可能是以上皮屏障功能破坏为特征的肠道疾病的新治疗靶点。
Changes in barrier function of the gastrointestinal tract are thought to contribute to the inflammatory bowel diseases Crohn’s disease and ulcerative colitis. Previous work in our lab demonstrated that apical exposure of intestinal epithelial cell lines to serine proteases results in an increase in transepithelial electrical resistance (TER). However, the underlying mechanisms governing this response are unclear. We aimed to determine the requirement for proteolytic activity, epidermal growth factor receptor (EGFR) activation, and downstream intracellular signaling in initiating and maintaining enhanced barrier function following protease treatment using a canine intestinal epithelial cell line (SCBN). We also examined the role of phosphorylation of myosin regulatory light chain on the serine protease-induced increase in TER through. It was found that proteolytic activity of the serine proteases trypsin and matriptase is required to initiate and maintain the protease-mediated increase in TER. We also show that MMP-independent EGFR activation is essential to the sustained phase of the protease response, and that Src kinases may mediate EGFR transactivation. PI3-K and ERK1/2 signaling were important in reaching a maximal increase in TER following protease stimulation; however, their upstream activators are yet to be determined. CK2 inhibition prevented the increase in TER induced by serine proteases. The bradykinin B(2) receptor was not involved in the change in TER in response to serine proteases, and no change in phosphorylation of MLC was observed after trypsin or matriptase treatment. Taken together, our data show a requirement for ongoing proteolytic activity, EGFR transactivation, as well as downstream PI3-K, ERK1/2, and CK2 signaling in protease-mediated barrier enhancement of intestinal epithelial cells. The pathways mediating enhanced barrier function by proteases may be novel therapeutic targets for intestinal disorders characterized by disrupted epithelial barrier function.