Treede Irina, Braun Annika, Sparla Richard, Kühnel Mark, Giese Thomas, Turner Jerrold R, Anes Elsa, Kulaksiz Hasan, Füllekrug Joachim, Stremmel Wolfgang, Griffiths Gareth, Ehehalt Robert
Department of Gastroenterology, University Hospital Heidelberg, INF 345, Heidelberg 69120, Germany, the; Cell Biology Program, European Molecular Biology Laboratory, Postfach 102209, Heidelberg 69117, Germany, the.
Department of Gastroenterology, University Hospital Heidelberg, INF 345, Heidelberg 69120, Germany, the.
J Biol Chem. 2007 Sep 14;282(37):27155-27164. doi: 10.1074/jbc.M704408200. Epub 2007 Jul 18.
We recently showed that mucus from patients with ulcerative colitis, a chronic inflammatory disorder of the colon, is characterized by a low level of phosphatidylcholine (PC) while clinical studies reveal that therapeutic addition of PC using slow release preparations is beneficial. The positive role of PC in this disease is still elusive. Here we tested the hypothesis that exogenous application of PC has anti-inflammatory properties using three model systems. First, human Caco-2 cells were treated with tumor necrosis factor-alpha (TNF-alpha) to induce a pro-inflammatory response via activation of NF-kappaB. Second, latex bead phagosomes were analyzed for their ability to assemble actin in vitro, a process linked to pro-inflammatory signaling and correlating with the growth versus killing of mycobacteria in macrophages. The third system used was the rapid assembly of plasma membrane actin in macrophages in response to sphingosine 1-phosphate. TNF-alpha induced a pro-inflammatory response in Caco-2 cells, including 1) assembly of plasma membrane actin; 2) activation of both MAPKs ERK and p38; 3) transport of NF-kappaB subunits to the nucleus; and 4) subsequent up-regulation of the synthesis of pro-inflammatory gene products. Exogenous addition of most PCs tested significantly inhibited these processes. Other phospholipids like sphingomyelin or phosphatidylethanolamine showed no effects in these assays. PC also inhibited latex bead phagosome actin assembly, the killing of Mycobacterium tuberculosis in macrophages, and the sphingosine 1-phosphate-induced actin assembly in macrophages. TNF-alpha induces the activation of signaling molecules and the reorganization of the actin cytoskeleton in human intestinal cells. Exogenous application of PC blocks pro-inflammatory signaling in Caco-2 cells, in phagosomes in vitro and facilitates intracellular survival of mycobacteria. We provide further evidence that actin assembly by membranes is part of the pro-inflammatory response. Collectively, these results provide a molecular foundation for the clinical studies showing a beneficial effect of PC therapy in ulcerative colitis.
我们最近发现，溃疡性结肠炎（一种结肠慢性炎症性疾病）患者的黏液具有磷脂酰胆碱（PC）水平低的特征，而临床研究表明，使用缓释制剂治疗性添加PC是有益的。PC在这种疾病中的积极作用仍不明确。在这里，我们使用三种模型系统检验了外源性应用PC具有抗炎特性的假设。首先，用人肿瘤坏死因子-α（TNF-α）处理人结肠癌细胞系Caco-2细胞，通过激活核因子-κB诱导促炎反应。其次，分析乳胶珠吞噬体在体外组装肌动蛋白的能力，这一过程与促炎信号传导相关，并与巨噬细胞中分枝杆菌的生长与杀伤相关。使用的第三个系统是巨噬细胞中响应鞘氨醇-1-磷酸的质膜肌动蛋白的快速组装。TNF-α在Caco-2细胞中诱导促炎反应，包括1）质膜肌动蛋白的组装；2）丝裂原活化蛋白激酶ERK和p38的激活；3）核因子-κB亚基向细胞核的转运；以及4）随后促炎基因产物合成的上调。测试的大多数外源性PC显著抑制了这些过程。其他磷脂如鞘磷脂或磷脂酰乙醇胺在这些试验中没有作用。PC还抑制乳胶珠吞噬体肌动蛋白组装、巨噬细胞中结核分枝杆菌的杀伤以及鞘氨醇-1-磷酸诱导的巨噬细胞肌动蛋白组装。TNF-α诱导人肠道细胞中信号分子的激活和肌动蛋白细胞骨架的重组。外源性应用PC可阻断Caco-2细胞、体外吞噬体中的促炎信号传导，并促进分枝杆菌在细胞内的存活。我们提供了进一步的证据，表明膜介导的肌动蛋白组装是促炎反应的一部分。总体而言，这些结果为临床研究提供了分子基础，表明PC治疗对溃疡性结肠炎有有益作用。
