Toll-like receptor 2 controls mucosal inflammation by regulating epithelial barrier function
Toll-like receptor 2 controls mucosal inflammation by regulating epithelial barrier function
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DOI：
10.1053/j.gastro.2007.02.056
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发表时间：
2007-04-01
期刊：
影响因子：
29.4
通讯作者：
Podolsky, D. K.
中科院分区：
文献类型：
--
作者：
Cario, E.;Gerken, G.;Podolsky, D. K.
背景与目的：Toll样受体是一类跨膜模式识别受体，在微生物识别和控制天然免疫反应中起重要作用。共生菌通过抑制肠道炎症在维持肠上皮屏障的耐受性和主动稳定性方面发挥着重要作用，但其作用机制尚不清楚。本研究的目的是确定TLR2在控制紧密连接(TJ)相关的肠上皮屏障完整性方面的功能相关性，以平衡粘膜动态平衡和炎症应激诱导的损伤。方法：在体外短期培养的模型肠上皮细胞(IEC-6、Caco-2)或原代培养的IEC中，采用Western blotting、共聚焦显微镜结合功能转染法和抑制剂研究TLR2配体(人工合成Pam(3)Cys-SK4[PCSK])诱导的信号转导通路的激活和TJ相关的分布。用标准方法诱导野生型、TLR2-/-和MyD88-/-小鼠DSS结肠炎。用末端脱氧核苷酸转移酶介导的dUTP-生物素缺口末端标记法检测自发性细胞凋亡。结果：体外和体外肠上皮细胞模型的数据显示，TLR2刺激通过MyD88促进PI3K/Akt介导的细胞存活，有效地保护TJ相关屏障组装免受应激损伤。此外，体内研究强调，TLR2介导的TJ调节关键决定了对肠道损伤和炎症的易感性。在缺乏TLR2或MyD88的小鼠中，炎症应激导致TJ相关的早期破坏，这与肠上皮屏障的抗凋亡失败有关。口服TLR2配体PCSK治疗结肠炎，通过在体内有效地恢复TJ相关的肠上皮完整性，显著抑制了粘膜炎症和细胞凋亡。结论：TLR2可能为药物调节黏膜损伤和肠炎症提供了靶点。
Background & Aims: Toll-like receptors (TLRs) represent a class of transmembrane pattern recognition receptors essential for microbial recognition and control of innate immune responses. Commensal bacteria play an important role in maintaining tolerance and active stability of the intestinal epithelial barrier by suppressing intestinal inflammation, yet the mechanisms of action are unknown. The aim of this study was to determine the functional relevance of TLR2 to control tight junction (TJ)-associated intestinal epithelial barrier integrity to balance mucosal homeostasis against inflammatory stress-induced damage. Methods: TLR2 ligand (synthetic Pam(3)Cys-SK4 [PCSK])-induced activation of signaling cascades and TJ-associated distribution was assessed by using Western blotting and confocal microscopy combined with functional transfection and inhibitor studies in model intestinal epithelial cell (IEC) lines (IEC-6, Caco-2) or primary IEC cultured short-term ex vivo. DSS colitis was induced by standard protocol in wild-type, TLR2-/-, and MyD88-/- mice. Spontaneous apoptosis was assessed by terminal deoxinucleotidyl-transferase-mediated dUTP-biotin nick end-labeling. Results: Data from in vitro and ex vivo models of intestinal epithelial cells revealed that TLR2 stimulation effectively preserves TJ-associated barrier assembly against stress-induced damage through promotion of PI3K/Akt-mediated cell survival via MyD88. Furthermore, in vivo studies underscored that TLR2-mediated TJ regulation critically determines susceptibility to intestinal injury and inflammation. Inflammatory stress in mice deficient of TLR2 or MyD88 induced early TJ-associated disruption interrelated with anti-apoptotic failure of the intestinal epithelial barrier. Oral treatment of colitis with the TLR2 ligand PCSK significantly suppressed mucosal inflammation and apoptosis by efficiently restoring TJ-associated integrity of the intestinal epithelium in vivo. Conclusion: TLR2 may provide a target to pharmacologically modulate mucosal injury and intestinal inflammation.