Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China.
Int J Oncol. 2018 Sep;53(3):1332-1342. doi: 10.3892/ijo.2018.4463. Epub 2018 Jun 29.
The downregulation of microRNA (miR)-381 has been detected in various diseases. The present study aimed to investigate the effects, and underlying mechanisms of miR-381 on inflammation and macrophage infiltration in polymyositis (PM). A mouse model of experimental autoimmune myositis (EAM) was generated in this study. Hematoxylin and eosin staining was conducted to detect the inflammation of muscle tissues. In addition, ELISA and immunohistochemistry were performed to determine the expression levels of associated factors, and reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect the expression levels of related mRNAs and proteins. A luciferase activity assay was used to confirm the binding of miR-381 and high mobility group box 1 (HMGB1) 3' untranslated region. Transwell assays were also performed to assess the migratory ability of macrophages. The results demonstrated that serum creatine kinase (s-CK), HMGB1 and cluster of differentiation (CD)163 expression in patients with PM were increased compared within healthy controls. Conversely, the expression levels of miR-381 were downregulated in patients with PM. Furthermore, high HMGB1 expression was associated with poor survival rate in patients with PM. In the mouse studies, muscle inflammation and CD163 expression were decreased in the anti-IL-17 and anti-HMGB1 groups, compared with in the EAM model group. The expression levels of s-CK, HMGB1, IL-17 and intercellular adhesion molecule (ICAM)-1 were also downregulated in response to anti-IL-17 and anti-HMGB1. These findings indicated that HMGB1 was closely associated with inflammatory responses. In addition, the present study indicated that transfection of macrophages with miR-381 mimics reduced the migration of inflammatory macrophages, and the expression levels of HMGB1, IL-17 and ICAM-1. Conversely, miR-381 inhibition exerted the opposite effects. The effects of miR-381 inhibitors were reversed by HMGB1 small interfering RNA. In conclusion, miR-381 may reduce inflammation and the infiltration of macrophages; these effects were closely associated with the downregulation of HMGB1.
miR-381 的下调已在各种疾病中被检测到。本研究旨在探讨 miR-381 对皮肌炎（PM）炎症和巨噬细胞浸润的影响及其潜在机制。本研究构建了实验性自身免疫性肌炎（EAM）的小鼠模型。通过苏木精和伊红染色检测肌肉组织的炎症情况。此外，还进行了 ELISA 和免疫组织化学检测，以确定相关因子的表达水平，逆转录定量聚合酶链反应和蛋白质印迹法用于检测相关 mRNA 和蛋白质的表达水平。通过荧光素酶活性测定证实了 miR-381 和高迁移率族蛋白 B1（HMGB1）3'非翻译区的结合。还进行了 Transwell 测定以评估巨噬细胞的迁移能力。结果表明，与健康对照组相比，PM 患者的血清肌酸激酶（s-CK）、HMGB1 和分化簇（CD）163 表达增加，而 PM 患者的 miR-381 表达水平下调。此外，HMGB1 高表达与 PM 患者的生存率降低有关。在小鼠研究中，与 EAM 模型组相比，抗 IL-17 和抗 HMGB1 组的肌肉炎症和 CD163 表达减少。s-CK、HMGB1、IL-17 和细胞间黏附分子（ICAM）-1 的表达水平也因抗 IL-17 和抗 HMGB1 而降低。这些发现表明 HMGB1 与炎症反应密切相关。此外，本研究表明转染巨噬细胞 miR-381 模拟物可减少炎症巨噬细胞的迁移以及 HMGB1、IL-17 和 ICAM-1 的表达水平。相反，miR-381 抑制则产生相反的效果。HMGB1 小干扰 RNA 可逆转 miR-381 抑制剂的作用。总之，miR-381 可能通过下调 HMGB1 来减轻炎症和巨噬细胞浸润。
