Umebashi Katsuyuki, Tokito Akinori, Yamamoto Masayoshi, Jougasaki Michihisa
Institute for Clinical Research, National Hospital Organization Kagoshima Medical Center, Kagoshima, Japan.
Neurohumoral Biology, Cooperative Department of Innovative Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
PLoS One. 2018 Jan 26;13(1):e0191659. doi: 10.1371/journal.pone.0191659. eCollection 2018.
Interleukin (IL)-33 is a member of the IL-1 cytokine family with dual functions as a traditional cytokine and as a transcriptional regulator. We recently reported that IL-33 up-regulated growth regulated oncogene (GRO)-α/CXCL1 expression in human vascular endothelial cells. The aim of this study was to investigate the effect of IL-33 on the expression of IL-8/CXCL8, another member of the CXC-chemokine family, and to elucidate its signaling pathways in human umbilical vein endothelial cells (HUVECs). Immunocytochemical staining and Western immunoblot analysis revealed that IL-33 augmented IL-8 protein expression in HUVECs. Real time reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) showed that IL-33 significantly increased IL-8 mRNA and secretion in a dose- and time-dependent manner. IL-33 preferentially stimulated proliferating subconfluent cells, and increased IL-8 secretion to a higher level compared with confluent cells. IL-33 also stimulated phosphorylations of c-Jun N-terminal kinase (JNK) and c-Jun, and enhanced activator protein (AP)-1 DNA-binding activity, all of which were suppressed by SP600125, a JNK inhibitor. Moreover, IL-33-induced IL-8 mRNA and secretion were also suppressed by SP600125. Transfection of c-Jun small interfering RNA into cultured HUVECs significantly reduced the IL-33-induced increase in IL-8 secretion from HUVECs. The present study demonstrates that IL-33 induces IL-8 expression via JNK/c-Jun/AP-1 pathway in human vascular endothelial cells, and provides a new insight into the role of IL-33-induced IL-8 in the pathophysiology of atherosclerosis and vascular inflammation.
白细胞介素（IL）-33是IL-1细胞因子家族的成员，具有作为传统细胞因子和转录调节因子的双重功能。我们最近报道，IL-33上调人血管内皮细胞中生长调节致癌基因（GRO）-α/CXCL1的表达。本研究的目的是探讨IL-33对CXC趋化因子家族的另一个成员IL-8/CXCL8表达的影响，并阐明其在人脐静脉内皮细胞（HUVECs）中的信号通路。免疫细胞化学染色和Western免疫印迹分析显示，IL-33增强了HUVECs中IL-8蛋白的表达。实时逆转录-聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）表明，IL-33以剂量和时间依赖性方式显著增加IL-8 mRNA和分泌。IL-33优先刺激增殖的亚汇合细胞，与汇合细胞相比，IL-8分泌增加到更高水平。IL-33还刺激c-Jun氨基末端激酶（JNK）和c-Jun的磷酸化，并增强激活蛋白（AP）-1的DNA结合活性，所有这些均被JNK抑制剂SP600125抑制。此外，SP600125也抑制IL-33诱导的IL-8 mRNA和分泌。将c-Jun小干扰RNA转染到培养的HUVECs中可显著降低IL-33诱导的HUVECs中IL-8分泌的增加。本研究表明，IL-33通过JNK/c-Jun/AP-1途径诱导人血管内皮细胞中IL-8的表达，并为IL-33诱导的IL-8在动脉粥样硬化和血管炎症病理生理学中的作用提供了新的见解。
