摘要
目的:转录因子干扰素调节因子(interferon regulatory factor,IRF)家族与Th17的发育密切相关,近年来发现Th17细胞在炎症性肠病的发病中发挥重要作用,本研究探讨IRF8对Th17发育及T细胞转染免疫介导的小鼠实验性肠炎的影响。方法:(1)采用流式细胞术分选野生型(WT)或IRF8全基因敲除(IRF8-/-)小鼠脾脏和淋巴结的naive CD4+T细胞(CD4+CD62L+CD44low),在Th1、Th2或Th17极化的条件下培养,采用流式细胞术检测Th1、Th2和Th17的比例。(2)建立实验性肠炎模型:采用免疫磁珠法分选WT或IRF8-/-小鼠中的脾脏和淋巴结中CD4+CD25+Treg,WT小鼠的CD4+CD45RBhiT细胞单独或者分别联合WT或IRF8-/-小鼠的CD4+CD25+Treg腹腔注射给RAG1-/-小鼠;WT或IRF8-/-小鼠的naive CD4+CD45RBhiT细胞腹腔注射给RAG1-/-小鼠;观察上述小鼠每周体重的变化,第5周时处死小鼠,进行结肠炎病理评分和肠系膜淋巴结T淋巴细胞亚群检测。结果:(1)IRF8-/-较WT的naive CD4+T细胞在极化条件下向Th17细胞分化更明显(P<0.01),而对Th1和Th2细胞的分化无影响(P>0.05)。(2)CD4+CD45RBhiT细胞转染给RAG1-/-小鼠,IRF8-/-较WT供体鼠引起的RAG1-/-小鼠体重显著降低(P<0.05),结肠炎评分显著增高(P<0.05),且肠系膜淋巴结中IL-17+CD4+细胞比例明显增高(P<0.01),而IFN-γ+CD4+和Foxp3+CD4+细胞比例无影响(P>0.05);IRF8-/-小鼠的CD4+CD25+Treg对WT小鼠CD4+CD45RBhiT细胞转染给RAG1-/-小鼠诱发的免疫介导的结肠炎显示出正常的免疫抑制作用。结论:转录因子IRF8基因敲除促进CD4+T细胞向Th17细胞分化,促进转染naive CD4+T细胞诱导的实验性结肠炎的发生,IRF8基因敲除小鼠Treg细胞免疫抑制功能正常。
AIM： To explore the impact of interferon regulatory factor 8 （IRF8） on Thl7 cell differentiation and naive CIM ~ T cell immune-mediated mouse experimental colitis. METHODS ： Naive CIM ~ T cells （CIM ~ CD62L ~ CD44l^W） from the spleens and lymph nodes of wild-type （WT） or IRF8 conventional knockout （IRF8-/- ） mice were sor- ted by flow cytometry. The naive CD4 ~ T cells were cultured under the polarized conditions of Thl and Th2 and Thl7, and then the ratios of Thl, Th2 and Thl7 in these cells were detected by flow cytometry. The CIM ~ CD25 ~ Treg cells were sor- ted by immunomagnetic beads, and CIM ~ CIM5RBbj T cells from the spleens and lymph nodes of WT or IRF8 -/- mice were purified by flow cytometry. To establish the experimental colitis model, the CD4 ~ CD45RBhi T ceils from WT mice or IRF8 -/- mice were intraperitoneally injected into the RAG1 -/- mice. The CD4 ＋ CD45RBhi T cells from WT mice were in- traperitoneally injected alone, or combined with CD4 ＋ CD25 ＋ Treg cells from WT mice or IRF8 -/- mice into the RAG1 -/-mice, respectively. The changes of the body weight in the experimental model mice were measured every week, and the mice were sacrificed at the fifth week for evaluating the colitis pathological score and T lymphocyte subtypes. RESULTS： Under polarized conditions, the ratio of Thl7 cells in IRF8-I- group was significantly higher than that in WT group, and no difference of the ratios of Thl or Th2 cells between these 2 groups was observed. The body weight of RAG1 -^- mice de- creased significantly, and the colon pathological scores of the RAG1 -i- mice injected with CD4 ~ CD45RBhiT cells from the IRF8 -j- mice were higher than those of the RAG1-i- mice injected with CD4 ~ CD45RBhi T ceils from the WT mice （P 〈 0.05）. Meanwhile, the ratio of IL-17 ~ CD4 ~ cells in mesenteric lymph nodes in IRFS-I- group was also higher than that in WT group, but no difference of the ratios of IFN-~/~ CD4 ~ cells or Foxp3 ~ CD4 ~ ceils between the 2 groups was ob- served. Moreover, CD4 ~ CD25 ~ Treg cells from the WT mice or the IRF8 -^- mice showed equivalent immunosuppression in the course of experimental colitis model, in which CD4 ~ CDd-SRBhi T cells from the WT mice were injected into the RAG1 -^- mice. CONCLUSION： Knockout of transcription factor IRF8 gene promotes the naive CD4 ＋T ceils to differenti- ate into Thl7 cells, consequently exacerbates immune-mediated experimental colitis. IRF8 -^- Treg cells display normal T effector suppressive activity in the process of immune-mediated experimental colitis.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2014年第1期144-149,共6页
Chinese Journal of Pathophysiology
基金
广东省自然科学基金资助项目(No.S2013010016726)
