无活性菱形蛋白 2 通过释放肿瘤坏死因子-α介导肠道炎症。

Inactive Rhomboid Protein 2 Mediates Intestinal Inflammation by Releasing Tumor Necrosis Factor-α.

机构信息

Department of Gastroenterology, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Republic of Korea.

Department of Gastroenterology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.

出版信息

Inflamm Bowel Dis. 2020 Jan 6;26(2):242-253. doi: 10.1093/ibd/izz239.

DOI:10.1093/ibd/izz239

PMID:31586441

Abstract

BACKGROUND

Tumor necrosis factor (TNF)-α is a major proinflammatory cytokine that plays a key role in inflammatory bowel disease (IBD). Inactive rhomboid protein 2 (iRhom2) is essential for activating TNF-α-converting enzyme (TACE) in immune cells, which regulates TNF-α release. The aim of the study was to investigate the role of iRhom2 in intestinal inflammation in IBD.

METHODS

The expression of iRhom2 and TACE in lipopolysaccharide (LPS)-stimulated COLO 205 and RAW 264.7 cells was assessed by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. The expression of iRhom2 and TACE in the colonic tissue of IBD patients and 2,4,6-trinitrobenzenesulfonic acid solution (TNBS)-treated mice was determined by RT-PCR and immunohistochemistry. To assess the role of iRhom2 in intestinal inflammation, colitis was induced in wild-type and iRhom2-/- mice by the administration of TNBS enema.

RESULTS

In LPS-stimulated COLO 205 and RAW 264.7 cells, the mRNA and protein levels of TACE and iRhom2 were upregulated. The expression of TACE and iRhom2 in the colon of the IBD patients and TNBS-treated mice was significantly enhanced. The inflammatory cells that expressed high levels of iRhom2 in the colon were identified as macrophages. Finally, iRhom2 deficiency ameliorated TNBS-induced colitis by inhibiting TNF-α release.

CONCLUSIONS

iRhom2 has an important role in intestinal inflammation through TNF-α secretion in immune cells, which suggests that iRhom2 could be a novel therapeutic target for IBD.

摘要

背景

肿瘤坏死因子（TNF）-α 是一种主要的促炎细胞因子，在炎症性肠病（IBD）中发挥关键作用。无活性的菱形蛋白 2（iRhom2）对于激活免疫细胞中的 TNF-α 转化酶（TACE）至关重要，该酶调节 TNF-α 的释放。本研究旨在探讨 iRhom2 在 IBD 中肠道炎症中的作用。

方法

通过逆转录聚合酶链反应（RT-PCR）和 Western blot 分析评估脂多糖（LPS）刺激的 COLO 205 和 RAW 264.7 细胞中 iRhom2 和 TACE 的表达。通过 RT-PCR 和免疫组织化学分析评估 IBD 患者和 2,4,6-三硝基苯磺酸（TNBS）处理的小鼠结肠组织中 iRhom2 和 TACE 的表达。为了评估 iRhom2 在肠道炎症中的作用，通过 TNBS 灌肠法在野生型和 iRhom2-/-小鼠中诱导结肠炎。

结果

在 LPS 刺激的 COLO 205 和 RAW 264.7 细胞中，TACE 和 iRhom2 的 mRNA 和蛋白水平均上调。IBD 患者和 TNBS 处理的小鼠结肠中 TACE 和 iRhom2 的表达明显增强。在结肠中表达高水平 iRhom2 的炎性细胞被鉴定为巨噬细胞。最后，iRhom2 缺乏通过抑制 TNF-α 的释放改善了 TNBS 诱导的结肠炎。