Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, China.
Division of Gastroenterology, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Bosn J Basic Med Sci. 2022 Oct 23;22(6):872-881. doi: 10.17305/bjbms.2022.7348.
Interleukin-1 receptor-associated kinase 1/4 (IRAK1/4) is the main kinase of the Toll-like receptor (TLR)-mediated pathway, considered a new target for treating inflammatory diseases. Studies showed a significant correlation between TLRs and inflammatory responses in ulcerative colitis (UC). Therefore, in this study, after inducing experimental colitis in mice with 3% dextran sulfate sodium (DSS), different concentrations of IRAK1/4 inhibitors were administered intraperitoneally. Then, the disease activity index was assessed, including the degree of pathological damage, by HE staining. Subsequently, while western blotting detected the TLR4/NF-κB pathway and intestinal barrier protein expression (Zonula-1, Occludin, Claudin-1, JAM-A), real-time polymerase chain reaction (RT-PCR) detected the mRNA expression levels of IRAK1/4 and mucin1/2. Furthermore, the expression levels of Zonula-1 and occludin were detected by immunofluorescence, including the plasma FITC-dextran 4000 concentration, to evaluate intestinal barrier permeability. However, ELISA measured the expression of inflammatory factors to reflect intestinal inflammation in mice. Investigations showed that the IRAK 1/4 inhibitor significantly reduced clinical symptoms and pathological DSS-induced colitis damage in mice and then inhibited the cytoplasmic and nuclear translocation of NF-κB p65, including the phosphorylation of IκBα and reduction in downstream inflammatory factor production. Therefore, we established that the IRAK1/4 inhibitor effectively improves colitis induced by DSS, partly by inhibiting the TLR4/NF-κB pathway, reducing inflammation, and maintaining the integrity of the colonic barrier.
白细胞介素-1 受体相关激酶 1/4 (IRAK1/4) 是 Toll 样受体 (TLR) 介导途径的主要激酶，被认为是治疗炎症性疾病的新靶点。研究表明，TLR 与溃疡性结肠炎 (UC) 的炎症反应之间存在显著相关性。因此，在这项研究中，用 3%葡聚糖硫酸钠 (DSS) 诱导小鼠实验性结肠炎后，通过腹腔内给予不同浓度的 IRAK1/4 抑制剂。然后，通过 HE 染色评估疾病活动指数，包括病理损伤程度。随后，通过 Western blot 检测 TLR4/NF-κB 通路和肠道屏障蛋白表达 (紧密连接蛋白-1、紧密连接蛋白-4、闭合蛋白-1、JAM-A)，通过实时聚合酶链反应 (RT-PCR) 检测 IRAK1/4 和粘蛋白 1/2 的 mRNA 表达水平。此外，通过免疫荧光检测 Zonula-1 和 occludin 的表达水平，包括血浆 FITC-葡聚糖 4000 浓度，以评估肠道屏障通透性。然而，ELISA 测量炎症因子的表达以反映小鼠肠道炎症。研究表明，IRAK1/4 抑制剂可显著减轻 DSS 诱导的小鼠临床症状和病理结肠炎损伤，进而抑制 NF-κB p65 的细胞质和核转位，包括 IκBα 的磷酸化和下游炎症因子产生的减少。因此，我们发现 IRAK1/4 抑制剂可有效改善 DSS 诱导的结肠炎，部分通过抑制 TLR4/NF-κB 通路，减轻炎症，维持结肠屏障的完整性。
