25-羟基胆固醇通过调控干扰素调节因子4抑制CD4^(+)T细胞IL-17的表达

25-Hydroxycholesterol inhibited IL-17 expression in CD4^(+)T cells via interferon regulatory factor 4

目的探讨25-羟基胆固醇(25-hydroxycholesterol,25-HC)对人外周血单个核细胞(PBMCs)产生IL-17的抑制作用及其机制。方法用抗人CD3抗体联合抗CD28抗体刺激培养外周血单个核细胞(PBMCs)和纯化CD4^(+)T细胞,加或不加25-HC进行培养,ELISA、ELISPOT和PCR检测IL-17和IFN-γ的表达;流式细胞术检测T细胞转录因子(RORγt、RUNX1和IRF4)的表达、细胞表面活化分子的表达以及T细胞分裂增殖情况。通过电转染过表达IRF4,检测其对IL-17表达的影响。结果25-HC呈时间和剂量依赖的方式抑制T细胞产生IL-17,且主要抑制CD4^(+)T细胞中IL-17的表达。进一步研究发现,25-HC抑制T细胞晚期活化分子的表达和细胞分裂增殖,抑制IL-17相关转录因子IRF4的表达;过表达IRF4后,25-HC对IL-17表达的抑制作用被恢复。结论25-HC抑制Th17细胞的活化和增殖,并通过下调IRF4的表达抑制CD4^(+)T细胞产生IL-17。25-HC可能是IL-17相关炎症性疾病的一个具有前景的调控靶点。

This study was designed to investigate the inhibitory effect of 25-hydroxycholesterol(25-HC)on the production of IL-17 by human peripheral blood mononuclear cells(PBMCs)and its mechanism.PBMCs and purified CD4^(+)T cells were stimulated with anti-human CD3 antibody combined with anti-CD28 antibody in the presence or absence of 25-HC,and the levels of IL-17 and IFN-γwere detected by ELISA,ELISPOT and PCR.The production of cytokines,surface activation molecules and transcription factors including RORγt,RUNX1 as well as IRF4 were analyzed by FACS.The concentration of IL-17 in cell culture supernatant was measured by ELISA after electrotransfection overexpression of IRF4.Data showed that 25-HC directly inhibited the production of IL-17 by CD4^(+)T cells in a time-and dose-dependent manner.Further studies showed that 25-HC inhibited T cell activation and proliferation as well as suppressed IL-17 production by downregulating IRF4 expression.After overexpression of IRF4,the inhibitory effect of 25-HC on IL-17 expression was restored.In summary,this study demonstrated that 25-HC inhibited the activation and proliferation of Th17 cells,and also inhibited the IL-17 production through down-regulating the expression of IRF4.These findings suggested that 25-HC may be a promising candidate for the IL-17-associated inflammatory diseases.