*Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; †Department of Pathology, Institute of Surgical Pathology, University Hospital of Zurich, Zurich, Switzerland; ‡Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; §Department of Surgery, Oberschwaben-Klinik, Ravensburg, Germany; and ‖Division of Gastroenterology and Hepatology, Stadtspital Triemli, Zurich, Switzerland.
Inflamm Bowel Dis. 2013 Dec;19(13):2878-87. doi: 10.1097/01.MIB.0000435760.82705.23.
Intestinal fistulae represent a severe complication of Crohn's disease (CD). The authors have demonstrated that epithelial-to-mesenchymal transition plays a pivotal role in their pathogenesis. High levels of interleukin-13 and tumor necrosis factor (TNF) are detected in myofibroblast-like transitional cells covering the fistula tracts. Here, a functional role was investigated for the transcription factor Ets-1, TNF, and the bacterial wall component (muramyl dipeptide [MDP]) in the pathogenesis of CD-associated fistulae.
Perianal fistulae from CD patients were analyzed by immunohistochemistry. Primary colonic lamina propria fibroblasts (CLPFs) were isolated from CD patients with or without fistulizing disease. Messenger RNA (mRNA) levels were assessed by real-time polymerase chain reaction in CLPF or HT29 intestinal epithelial cells (IECs) grown as monolayers or spheroids.
Strong expression of Ets-1 transcription factor was demonstrated in transitional cell covering the fistula tracts by immunohistochemistry. TNF induced mRNA expression of ETS-1 and β6-integrin in HT29 IEC and in CLPF from fistulizing CD patients. These effects could be fully blocked by administration of anti-TNF antibodies. In HT29 cells, TNF further induced mRNA levels of TNF and transforming growth factor beta by treatment for 24 hours. In fistula CLPF derived from CD patients, TNF induced expression of β6-integrin, TNF, and transforming growth factor beta. Of note, the bacterial wall component, MDP, induced mRNA levels of ETS-1, transforming growth factor beta, interleukin-13, SNAIL1, and β6-integrin in HT29 IEC monolayers and fistula CLPF by treatment for 24 hours.
TNF and MDP induce the expression of factors associated with epithelial-to-mesenchymal transition and invasion in IEC and fistula CLPF. Our findings indicate that TNF and MDP might synergize in the pathogenesis of CD-associated fistulae.
肠瘘是克罗恩病（CD）的一种严重并发症。作者已经证明上皮-间充质转化在其发病机制中起着关键作用。在覆盖瘘管的肌纤维母细胞样过渡细胞中检测到高水平的白细胞介素-13 和肿瘤坏死因子（TNF）。在这里，研究了转录因子 Ets-1、TNF 和细菌壁成分（ muramyl dipeptide [MDP]）在 CD 相关瘘管发病机制中的功能作用。
通过免疫组织化学分析 CD 患者的肛周瘘。从患有或不患有瘘病的 CD 患者中分离出原发性结肠固有层成纤维细胞（CLPF）。通过实时聚合酶链反应评估单层或球体培养的 CLPF 或 HT29 肠上皮细胞（IEC）中的 mRNA 水平。
免疫组织化学显示，过渡细胞强烈表达 Ets-1 转录因子，覆盖瘘管。TNF 在 HT29 IEC 和来自瘘管 CD 患者的 CPLF 中诱导 ETS-1 和 β6-整联蛋白的 mRNA 表达。这些作用可以通过施用抗 TNF 抗体完全阻断。在 HT29 细胞中，TNF 在 24 小时的治疗后进一步诱导 TNF 和转化生长因子β的 mRNA 水平。在来自 CD 患者的瘘管 CPLF 中，TNF 诱导 β6-整联蛋白、TNF 和转化生长因子β的表达。值得注意的是，细菌壁成分 MDP 在 24 小时的治疗后诱导 HT29 IEC 单层和瘘管 CPLF 中 ETS-1、转化生长因子β、白细胞介素-13、SNAIL1 和 β6-整联蛋白的 mRNA 水平。
TNF 和 MDP 诱导 IEC 和瘘管 CPLF 中与上皮-间充质转化和侵袭相关的因子表达。我们的研究结果表明，TNF 和 MDP 可能在 CD 相关瘘管的发病机制中协同作用。
