Shan Kai, Pang Rongrong, Zhao Chenhui, Liu Xiaomei, Gao Wenxing, Zhang Jing, Zhao Dan, Wang Yingwei, Qiu Wen
Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu 211166, China.
Department of Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
Cell Mol Immunol. 2017 May 1;14(11):909-23. doi: 10.1038/cmi.2017.12.
Interleukin 17 (IL-17) is increasingly recognized as a key factor that contributes to the pathogenesis of multiple sclerosis (MS) and its experimental mouse autoimmune encephalomyelitis (EAE) model. However, the roles and regulatory mechanisms of IL-17-induced pro-inflammatory cytokine production in EAE mice remain largely unclear. In this study, the expression of IL-17, hypoxia inducible factor-1α (HIF-1α), IL-1β, IL-6 and microRNA-497 (miR-497), as well as their intrinsic associations, was investigated using EAE model mice and cultured astrocytes exposed to IL-17 in vitro. We observed markedly increased production of IL-17, HIF-1α, IL-1β and IL-6 in the brain tissues of EAE mice, while the expression and secretion of HIF-1α, IL-1β and IL-6 were also significantly increased when cultured primary astrocytes from mice were stimulated with IL-17. Meanwhile, the expression of miR-497 was downregulated both in vivo and in vitro. Subsequent in vitro experiments revealed that IL-17 induced the production of IL-1β and IL-6 in astrocytes through the upregulation of HIF-1α as a transcriptional factor, indicating that IL-17-mediated downregulation of miR-497 enhanced HIF-1α expression. Furthermore, astrocyte-specific knockdown of IL-17RA and HIF-1α or astrocyte-specific overexpression of miR-497 by infection with different lentiviral vectors containing an astrocyte-specific promotor markedly decreased IL-1β and IL-6 production in brain tissues and alleviated the pathological changes and score of EAE mice. Collectively, these findings indicate that decreased miR-497 expression is responsible for IL-17-triggered high HIF-1α expression and consequent IL-1β and IL-6 production by astrocytes in EAE mice.Cellular & Molecular Immunology advance online publication, 1 May 2017; doi:10.1038/cmi.2017.12.
白细胞介素17（IL-17）日益被认为是促成多发性硬化症（MS）及其实验性小鼠自身免疫性脑脊髓炎（EAE）模型发病机制的关键因素。然而，IL-17诱导促炎细胞因子在EAE小鼠中产生的作用和调控机制仍不清楚。在本研究中，使用EAE模型小鼠和体外暴露于IL-17的培养星形胶质细胞，研究了IL-17、缺氧诱导因子-1α（HIF-1α）、IL-1β、IL-6和微小RNA-497（miR-497）的表达及其内在关联。我们观察到EAE小鼠脑组织中IL-17、HIF-1α、IL-1β和IL-6的产生显著增加，而当用IL-17刺激从小鼠分离的原代培养星形胶质细胞时，HIF-1α、IL-1β和IL-6的表达和分泌也显著增加。同时，miR-497的表达在体内和体外均下调。随后的体外实验表明，IL-17通过上调作为转录因子的HIF-1α诱导星形胶质细胞中IL-1β和IL-6的产生，表明IL-17介导的miR-497下调增强了HIF-1α的表达。此外，通过感染含有星形胶质细胞特异性启动子的不同慢病毒载体，对IL-17RA和HIF-1α进行星形胶质细胞特异性敲低或对miR-497进行星形胶质细胞特异性过表达，可显著降低脑组织中IL-1β和IL-6的产生，并减轻EAE小鼠的病理变化和评分。总的来说，这些发现表明miR-497表达降低是EAE小鼠中IL-17触发的星形胶质细胞高HIF-1α表达以及随后IL-1β和IL-6产生的原因。《细胞与分子免疫学》在线优先发表，2017年5月1日；doi:10.1038/cmi.2017.12
