Department of Medicine, The Jack Bell Research Centre, 2660 Oak Street, Vancouver, British Columbia, V6H 3Z6, Canada.
BMC Immunol. 2011 Aug 1;12:42. doi: 10.1186/1471-2172-12-42.
The role of integrin signaling in mucosal inflammation is presently unknown. Hence, we aimed to investigate the role of epithelial-derived integrin-linked kinase (ILK), a critical integrin signaling intermediary molecule, in colonic inflammation.
Conditional intestinal epithelial cell ILK knockout mice were used for assessment of acute and chronic dextran sodium sulfate (DSS)-induced colitis. Disease activity was scored using standard histological scoring, mucosal cytokines were measured using ELISA, chemokines were determined using reverse-transcription polymerase chain reaction, as well as Q-PCR, and intracellular cytokine staining performed using FACS analysis.
In both acute and chronic DSS-induced colitis, compared to wild-type mice, ILK-ko mice exhibit less weight loss, and have reduced inflammatory scores. In an in vitro model system using HCT116 cells, we demonstrate that si-RNA mediated down-regulation of ILK results in a reduction in monocyte chemoattractant protein 1 (MCP1, CCL2) chemokine expression. A reduction in CCL2 levels is also observed in the tissue lysates of chronically inflamed colons from ILK-ko mice. Examination of mesenteric lymph node lymphocytes from ILK-ko mice reveals that there is a reduction in the levels of IFN gamma using intracellular staining, together with an increase in Foxp3+ T regulatory cells. Immunohistochemistry demonstrates that reduced fibronectin expression characterizes the inflammatory lesions within the colons of ILK-ko mice. Intriguingly, we demonstrate that fibronectin is directly capable of downregulating T regulatory cell development.
Collectively, the data indicate for the first time that ILK plays a pro-inflammatory role in intestinal inflammation, through effects on chemokine expression, the extracellular matrix and immune tolerance.
整合素信号在黏膜炎症中的作用目前尚不清楚。因此，我们旨在研究上皮细胞衍生的整合素连接激酶（ILK）在结肠炎症中的作用，ILK 是一种关键的整合素信号中介分子。
使用条件性肠上皮细胞 ILK 敲除小鼠来评估急性和慢性葡聚糖硫酸钠（DSS）诱导的结肠炎。使用标准组织学评分评估疾病活动度，使用 ELISA 测量黏膜细胞因子，使用逆转录聚合酶链反应（RT-PCR）和 Q-PCR 测定趋化因子，使用 FACS 分析进行细胞内细胞因子染色。
与野生型小鼠相比，在急性和慢性 DSS 诱导的结肠炎中，ILK-ko 小鼠的体重减轻较少，炎症评分降低。在使用 HCT116 细胞的体外模型系统中，我们证明 si-RNA 介导的 ILK 下调导致单核细胞趋化蛋白 1（MCP1，CCL2）趋化因子表达减少。ILK-ko 小鼠慢性炎症结肠组织的裂解物中也观察到 CCL2 水平降低。对 ILK-ko 小鼠肠系膜淋巴结淋巴细胞的检查表明，细胞内染色显示 IFNγ水平降低，同时 Foxp3+T 调节细胞增加。免疫组织化学显示，ILK-ko 小鼠结肠的炎症病变中纤维连接蛋白表达减少。有趣的是，我们证明纤维连接蛋白可直接下调 T 调节细胞的发育。
总之，这些数据首次表明，ILK 通过对趋化因子表达、细胞外基质和免疫耐受的影响，在肠道炎症中发挥促炎作用。
