State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
Cytokine. 2011 Dec;56(3):581-8. doi: 10.1016/j.cyto.2011.08.023. Epub 2011 Sep 3.
Proinflammatory cytokines play vital roles in intestinal barrier function disruption. YC-1 has been reported to have potent anti-inflammatory properties, and to be a potential agent for sepsis treatment. Here, we investigated the protective effect of YC-1 against intestinal barrier dysfunction caused by interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α). To assess the protective effect of YC-1 on intestinal barrier function, Caco-2 monolayers treated with simultaneous IFN-γ and TNF-α were used to measure transepithelial electrical resistance (TER) and paracellular permeability. To determine the mechanisms involved in the protective action of YC-1, expression and distribution of tight junction proteins ZO-1 and occludin in Caco-2 monolayers challenged with simultaneous IFN-γ and TNF-α were analyzed by Western blot and immunofluorescence, respectively. Expressions of phosphorylated myosin light chain (MLC), MLC kinase (MLCK) and hypoxia-inducible factor-1α (HIF-1α) were analyzed by Western blot in IFN-γ and TNF-α-treated Caco-2 monolayers. It was found that YC-1 attenuated barrier dysfunction caused by IFN-γ and TNF-α, and also prevented IFN-γ and TNF-α-induced morphological redistribution of tight junction proteins ZO-1 and occludin in Caco-2 monolayers. In addition, YC-1 suppressed IFN-γ and TNF-α-induced upregulation of MLC phosphorylation and MLCK protein expression. Furthermore, enhanced expression of HIF-1α in Caco-2 monolayers treated with IFN-γ and TNF-α was also suppressed by YC-1. It is suggested that YC-1, by downregulating MLCK expression, attenuates intestinal barrier dysfunction induced by IFN-γ and TNF-α, in which HIF-1α inhibition, at least in part, might by involved. YC-1 may be a potential agent for treatment of intestinal barrier disruption in inflammation.
促炎细胞因子在肠道屏障功能障碍中发挥重要作用。YC-1 已被报道具有强大的抗炎特性，是治疗败血症的潜在药物。在这里，我们研究了 YC-1 对干扰素-γ (IFN-γ) 和肿瘤坏死因子-α (TNF-α) 引起的肠道屏障功能障碍的保护作用。为了评估 YC-1 对肠道屏障功能的保护作用，我们使用同时用 IFN-γ 和 TNF-α 处理的 Caco-2 单层细胞来测量跨上皮电阻 (TER) 和旁细胞通透性。为了确定 YC-1 的保护作用涉及的机制，我们通过 Western blot 和免疫荧光分别分析了同时用 IFN-γ 和 TNF-α 处理的 Caco-2 单层细胞中紧密连接蛋白 ZO-1 和闭合蛋白的表达和分布。通过 Western blot 分析 IFN-γ 和 TNF-α 处理的 Caco-2 单层细胞中磷酸化肌球蛋白轻链 (MLC)、肌球蛋白轻链激酶 (MLCK) 和缺氧诱导因子-1α (HIF-1α) 的表达。结果发现，YC-1 减轻了 IFN-γ 和 TNF-α 引起的屏障功能障碍，还防止了 IFN-γ 和 TNF-α 诱导的 Caco-2 单层细胞中紧密连接蛋白 ZO-1 和闭合蛋白的形态重新分布。此外，YC-1 抑制了 IFN-γ 和 TNF-α 诱导的 MLC 磷酸化和 MLCK 蛋白表达上调。此外，YC-1 还抑制了 IFN-γ 和 TNF-α 处理的 Caco-2 单层细胞中 HIF-1α 的增强表达。这表明，YC-1 通过下调 MLCK 表达，减轻了 IFN-γ 和 TNF-α 诱导的肠道屏障功能障碍，其中 HIF-1α 抑制至少部分参与其中。YC-1 可能是治疗炎症性肠道屏障破坏的潜在药物。
