Objective: To investigate the expression level of Kruppel-like transcription factor family member KLF11 in intestinal mucosal tissues of Crohn's disease (CD) and its regulatory effect on intestinal inflammation in CD-like colitis.
Methods: We examined KLF11 expression levels in diseased and normal colon mucosal tissues from 12 CD patients and 12 patients with colorectal cancer using immunofluorescence staining. KLF11 expression was also detected in the colon mucosal tissues of a mouse model of 2, 4, 6-trinitrobenesulfonic acid (TNBS)-induced colitis. A recombinant adenoviral vector was used to upregulate KLF11 expression in the mouse models and the changes in intestinal inflammation was observed. A Caco-2 cell model with stable KLF11 overexpression was constructed by lentiviral infection. The effect of KLF11 overexpression on expressions of JAK2/STAT3 signaling pathway proteins was investigated using immunoblotting in both the mouse and cell models. The mouse models were treated with coumermycin A1, a JAK2/STAT3 signaling pathway agonist, and the changes in intestinal inflammatory responses were observed.
Results: The expression level of KLF11 was significantly lowered in both the clinical specimens of diseased colon mucosal tissues and the colon tissues of mice with TNBS-induced colitis (P < 0.05). Adenovirus-mediated upregulation of KLF11 significantly improved intestinal inflammation and reduced the expression levels of inflammatory factors in the intestinal mucosa of the colitis mouse models (P < 0.05). Overexpression of KLF11 significantly inhibited the expression levels of p-JAK2 and p-STAT3 in intestinal mucosal tissues of the mouse models and in Caco-2 cells (P < 0.05). Treatment with coumermycin A1 obviously inhibited the effect of KLF11 upregulation for improving colitis and significantly increased the expression levels of inflammatory factors in the intestinal mucosa of the mouse models (P < 0.05).
Conclusion: KLF11 is downregulated in the intestinal mucosa in CD, and upregulation of KLF11 can improve intestinal inflammation and reduce the production of inflammatory factors probably by inhibiting the JAK2/STAT3 signaling pathway.
目的: 分析Kruppel样转录因子11（KLF11）在克罗恩病（CD）肠黏膜组织中的表达情况，并探究其对CD样结肠炎的作用和机制。
方法: 以本院收集的CD患者结肠标本为实验组（CD，n=12），CRC患者结肠标本为对照组（Control，n=12），分析KLF11在病变和正常结肠黏膜组织中的表达差异；构建TNBS诱导的小鼠模型，分析KLF11在小鼠结肠黏膜组织中的表达情况；利用腺相关病毒感染上调KLF11在小鼠中的表达，并观察其对小鼠CD样结肠炎的影响；通过慢病毒感染构建Caco-2细胞KLF11高表达稳定体系，并利用体内外免疫印迹实验探究KLF11对JAK2/STAT3信号通路蛋白的影响；采用信号通路激动剂处理KLF11表达上调的小鼠，验证肠道炎症反应的相关机制。
结果: 免疫荧光染色分析显示，病变肠黏膜组织中KLF11表达水平较低（P < 0.05），而TNBS小鼠结肠标本KLF11表达水平同样较低（P < 0.05）；通过腺相关病毒感染小鼠发现，上调KLF11能够改善TNBS小鼠肠炎症症状，并降低肠黏膜炎症因子的表达水平（P < 0.05）；利用慢病毒感染Caco-2细胞，通过免疫印迹筛选KLF11稳定高表达的细胞株（P < 0.05）；体内外免疫印迹实验均显示，上调KLF11抑制了小鼠肠黏膜组织及Caco-2细胞中p-JAK2和p-STAT3的表达水平；经JAK2/STAT3激活剂香豆霉素A1（COU）干预后显示，上调KLF11未能改善小鼠肠道炎症，同时肠黏膜炎症因子表达水平增加（P < 0.05）。
结论: KLF11在CD肠黏膜中低表达，上调KLF11能改善肠炎症状、减少炎症因子分泌，其可能通过抑制JAK2/STAT3信号通路拮抗肠道炎症反应。
Keywords: Crohn's disease; JAK2/STAT3; KLF11; intestinal inflammation.