miR-221 抑制 ICAM-1 的翻译并调节人胆管细胞中干扰素-γ诱导的 ICAM-1 表达。

miR-221 suppresses ICAM-1 translation and regulates interferon-gamma-induced ICAM-1 expression in human cholangiocytes.

机构信息

Department of Medical Microbiology and Immunology, Creighton University Medical Center, Omaha, Nebraska 68178, USA.

出版信息

Am J Physiol Gastrointest Liver Physiol. 2010 Apr;298(4):G542-50. doi: 10.1152/ajpgi.00490.2009. Epub 2010 Jan 28.

Abstract

Aberrant cholangiocyte reactions in response to inflammatory stimuli are important pathogenic factors for the persistent biliary inflammation in patients with cholangiopathies. Overexpression of intercellular cell adhesion molecule-1 (ICAM-1) in cholangiocytes is a common pathological feature in inflammatory cholangiopathies and can promote cholangiocyte interactions with effector lymphocytes in the portal region. In this study, we tested the involvement of miRNA-mediated posttranscriptional regulation in IFN-gamma-induced ICAM-1 expression in cholangiocytes. Using both immortalized and nonimmortalized human cholangiocyte cell lines, we found that IFN-gamma activated ICAM-1 transcription and increased ICAM-1 protein expression. Inhibition of ICAM-1 transcription could only partially block IFN-gamma-induced ICAM-1 expression at the protein level. In silico target prediction analysis revealed complementarity of miR-221 to the 3'-untranslated region of ICAM-1 mRNA. Targeting of ICAM-1 3'-untranslated region by miR-221 resulted in translational repression in cholangiocytes but not ICAM-1 mRNA degradation. Functional inhibition of miR-221 with anti-miR-221 induced ICAM-1 protein expression. Moreover, IFN-gamma stimulation decreased miR-221 expression in cholangiocytes in a signal transducer and activator of transcription 1-dependent manner. Transfection of miR-221 precursor abolished IFN-gamma-stimulated ICAM-1 protein expression. In addition, miR-221-mediated expression of ICAM-1 on cholangiocytes showed a significant influence on the adherence of cocultured T cells. These findings indicate that both transcriptional and miRNA-mediated posttranscriptional mechanisms are involved in IFN-gamma-induced ICAM-1 expression in human cholangiocytes, suggesting an important role for miRNAs in the regulation of cholangiocyte inflammatory responses.

摘要

胆管细胞对炎症刺激的异常反应是胆病患者持续性胆管炎症的重要致病因素。细胞间黏附分子-1(ICAM-1)在胆管细胞中的过度表达是炎症性胆管病的共同病理特征,可促进胆管细胞与门脉区效应淋巴细胞的相互作用。在这项研究中,我们测试了 miRNA 介导的转录后调控在 IFN-γ诱导的胆管细胞中 ICAM-1 表达中的作用。使用永生化和非永生化的人胆管细胞系,我们发现 IFN-γ激活了 ICAM-1 的转录并增加了 ICAM-1 蛋白的表达。ICAM-1 转录的抑制只能部分阻断 IFN-γ诱导的胆管细胞中 ICAM-1 蛋白的表达。计算机预测分析显示 miR-221 与 ICAM-1 mRNA 的 3'-非翻译区互补。miR-221 靶向 ICAM-1 3'-非翻译区导致胆管细胞中的翻译抑制,但不导致 ICAM-1 mRNA 降解。用抗 miR-221 抑制 miR-221 的功能诱导了 ICAM-1 蛋白的表达。此外,IFN-γ刺激以转录激活因子 1 依赖的方式降低胆管细胞中 miR-221 的表达。miR-221 前体的转染消除了 IFN-γ刺激的 ICAM-1 蛋白表达。此外,miR-221 介导的胆管细胞上的 ICAM-1 表达对共培养的 T 细胞的黏附具有显著影响。这些发现表明,IFN-γ 诱导的人胆管细胞中 ICAM-1 表达既涉及转录机制,也涉及 miRNA 介导的转录后机制,提示 miRNA 在胆管细胞炎症反应的调控中起重要作用。

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