Department of Surgery I, Charité School of Medicine, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany.
J Gastrointest Surg. 2010 Feb;14(2):388-97. doi: 10.1007/s11605-009-1068-3. Epub 2009 Oct 24.
Snail, a transcription factor linked to epithelial to mesenchymal transition (EMT) during embryonic development and tumor progression, is associated with migration of cells. During inflammation and tissue injury, cell movement is also observed to provide the first line of defense against bacteria and to promote wound healing. Therefore, we studied the function of Snail in activated macrophages in a variety of inflammatory processes.
In this study, we examined the expression and localization of Snail during inflammation and tissue injury in rats and human tissue specimens, by immunohistochemistry, Western blot, and real-time PCR. We investigated Snail expression after stimulation of macrophages with TGF-beta1, LPS, Interleukin-8, and MMP-3 in vitro. To further understand the role of Snail in activated macrophages, we used Stealth siRNA against Snail, transfected the human macrophage cell line THP-1, and measured migration of cells in an in vitro invasion assay.
We found a strong, transient, and time-dependent activation of Snail in migrating macrophages at the sites of injury in vivo and in vitro, as well as in patients with inflammatory bowel disease. Furthermore, we showed that induction of Snail in macrophages is dependent on TGF-beta1 signaling pathway. Downregulation of Snail by Stealth siRNA led to impaired migration of THP-1 cells in an invasion assay after stimulation with TGF-beta1.
We conclude that TGF-beta1 induced migration of activated macrophages during inflammation and wound healing is mediated by snail. These results give insights in a novel EMT-like mechanism present in immune cell movement during tissue injury.
蜗牛是一种转录因子，与胚胎发育和肿瘤进展过程中的上皮-间充质转化（EMT）有关，与细胞迁移有关。在炎症和组织损伤过程中，也观察到细胞运动为抵抗细菌提供第一道防线，并促进伤口愈合。因此，我们研究了蜗牛在各种炎症过程中激活的巨噬细胞中的功能。
在这项研究中，我们通过免疫组织化学、Western blot 和实时 PCR 检查了大鼠和人组织标本中蜗牛在炎症和组织损伤期间的表达和定位。我们研究了巨噬细胞在体外受到 TGF-β1、LPS、白细胞介素-8 和 MMP-3 刺激后蜗牛的表达情况。为了进一步了解蜗牛在激活的巨噬细胞中的作用，我们使用针对蜗牛的 Stealth siRNA，转染人巨噬细胞系 THP-1，并在体外侵袭试验中测量细胞迁移。
我们发现，在体内和体外损伤部位以及炎症性肠病患者中，迁移的巨噬细胞中蜗牛的表达强烈、短暂且具有时间依赖性。此外，我们表明，巨噬细胞中蜗牛的诱导依赖于 TGF-β1 信号通路。用 Stealth siRNA 下调蜗牛导致 TGF-β1 刺激后 THP-1 细胞在侵袭试验中的迁移受损。
我们得出结论，TGF-β1 在炎症和伤口愈合过程中诱导激活的巨噬细胞迁移是由蜗牛介导的。这些结果为组织损伤过程中免疫细胞运动中存在的新型 EMT 样机制提供了深入了解。
