2012-01-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/643172摘要：初生的先趨輔助 T 細胞在接受抗原刺激後，會分化為成熟的輔助 T 細胞。這些輔助 T 細胞有三種亞型：輔助T 第一型(Th1)或輔助T 第二型(Th2)或輔助T 第十七型(Th17)細胞。Th1 細胞藉由輔助T 細胞第一型專一轉錄因子T-bet及Ets-1 產生干擾素γ和介白素二。相對的，Th2 細胞藉由輔助T細胞第二型專一轉錄因子GATA-3及c-Maf 產生介白素四、五及十三。Th17 細胞藉由輔助T 細胞第十七型專一轉錄因子 RORγt產生介白素十七 F、介白素二十一以及介白素二十二。不正常的輔助T 細胞免疫反應將導致病理上的不正常。因此，Th1/Th2/Th17 反應在臨床上有其重要性。並且，T 細胞專一轉錄因子 T-bet與 Ets-1/GATA-3 及 c-Maf/RORγt已被證明在決定Th1/Th2/Th17走向與輔助型 T 細胞的免疫反應上扮演主要的角色。SUMO 蛋白是一種在所有的真核細胞中存在的高度保留蛋白，並且對許多真核細胞是生存所必需的。SUMO 蛋白的修飾對蛋白質的功能調控上扮演關鍵角色。我們證明 c-Maf 在體內及體外都會被 SUMO 分子修飾。並且，c-Maf 只以離胺酸 33殘基與 SUMO 分子鍵結。我們觀察到 SUMO 缺乏的 K33R c-Maf 增加了介白素四基因的表現。在HEK293T與DO11.10細胞中，SUMO-1 分子降低了而SENP-1 增加了野生型c-Maf 的活性，但SUMO 缺乏的 K33R c-Maf 之活性則不受影響。我們也發現介白素二十一可以被 c-Maf 而非 T-bet或GATA3誘發，而且c-Maf 在介白素二十一啟動子上的活性也會因其SUMO 化而被抑制。因此，我們認為 c-Maf 的 SUMO 化對其調控輔助 T 第二型的介白素四與與輔助 T 第十七型細胞的介白素二十一基因表現上扮演重要的角色。然而，c-Maf 在輔助型 T 細胞上如何會被 SUMO 化而影響介白素四與與介白素二十一基因的表現則仍不清楚。在這個計畫中，我們將研究在輔助 T 第二型或輔助 T 第十七型細胞中 c-Maf 是否會被 SUMO 化，同時研究 SUMO 化如何影響 c-Maf 去調控輔助 T 第二型的介白素四與與輔助 T 第十七型細胞的介白素二十一基因表現。更進一步的，我們將研究 SUMO 化的 c-Maf 對 T 細胞的分化與免疫反應的影響。 <br> Abstract: Naïve CD4+ precursor helper T (Th) cells differentiate into mature effector Th cells upon encountering antigen. Th cells have three subtypes, Th1, Th2 and Th17, depending on the pattern of cytokine secretion. Th1 cells secrete IFN-γ and IL-2 regulated by Th1-specific transcription factors T-bet and Ets-1whereas Th2 cells secrete IL-4, IL-5 and IL-13 controlled by Th2-specific transcription factors GATA3 and c-Maf. Th17 cells secrete IL-17F, IL-21 and IL-22 mediated by Th17-specific transcription factor RORγt. Dysregulated Th1 or Th2 or Th17 responses may cause pathological malfunction. Therefore, Th1/Th2/Th17 responses have clinical importance. Furthermore, Th-specific transcription factor c-Maf has been identified and shown to play the major role in the decision of Th pathway and Th immune responses. SUMOs (small ubiquitin-like modifiers) constitute a highly conserved protein family found in all eukaryotes and are required for viability of most eukaryotic cells. SUMOylation plays a major role in regulating protein function. We demonstrate that SUMO moleculesmodify c-Maf both in vitro and in vivo. In addition, c-Maf conjugates with SUMO molecules only on lysine-33 residue. We observe that SUMO-deficient K33R c-Maf increases the expression of IL-4 gene. On both HEK293T and DO11.10 T cell lines, SUMO-1 attenuates wild type-, but not SUMO-deficient K33R-c-Maf activity, and SENP-1 enchances wild type c-Maf’s. In addition, we report that IL-21 can be induced by c-Maf, but not T-bet or GATA3, in a dose dependant manner. Moreover, c-Maf transactivity on IL-21 promoter was suppressed by SUMOylation. Therefore, we propose that the SUMOylation might play an important role in controlling c-Maf for regulation of IL-4 and IL-21 cytokine gene expressions in Th2 and Th17 cells, respectively. However, whether c-Maf would be SUMOylated in Th cells and thus lead to modulation of IL-4 and IL-21 cytokine gene expressions remains unclear. Here, we focus to investigate whether the SUMOylation of c-Maf would occur in Th2 and Th17 cells and dissect how the SUMOylation of c-Maf affects the expression IL-4 and IL-21 cytokine genes in Th2 and Th17, respectively. Furthermore, we will determine the effect of Th differentiation and immune responses by the SUMOylated c-Maf.細胞激素調控介白素四介白素二十一SUMO 化c-Maf輔助 T 細胞regulation of cytokine geneIL-4IL-21SUMOylationc-Mafhelper T cells