繆希椿臺灣大學：免疫學研究所林俊國Lin, Chun-KuoChun-KuoLin2007-11-292018-07-092007-11-292018-07-092005http://ntur.lib.ntu.edu.tw//handle/246246/63293細胞激素 (cytokine)在許多之前研究中已經被指出能夠決定輔助型T細胞 (T helper cell)分化的命運。第一類輔助型T細胞 (Th1 cell)會分泌第一類細胞激素，例如干擾素γ(IFN-γ)；而第二類輔助型T細胞(Th2 cell)則會分泌第二類細胞激素，例如：介白素4(IL- 4)、介白素5 (IL-5)、介白素10 (IL-10)及介白素13 (IL-13)。這些細胞激素能分別促進更多未分化的輔助型T細胞分化成第一類或第二類輔助型T細胞。在輔助型T細胞中，c-Maf專一地扮演著調控介白素4表現的轉錄因子 (transcription factor)的角色。當第二類輔助型T細胞活化時，會表現更多介白素4，因而促進更多第二類輔助型T細胞的分化。當c-Maf在輔助型T細胞的表現有缺陷時，則會導致輔助型T細胞朝向第一類輔助型T細胞的型態發展，也因此加劇許多由第一類輔助型T細胞所導致的疾病，例如：自體免疫性糖尿病 (antoimmune diabetes)。在此，我們發現另一個Maf蛋白家族的成員－MafB，在經過in vitro活化後之in vitro或in vivo 培養的 EL4細胞株中皆有顯著的表現。此外，在活化之後，MafB的表現量在趨向第一類輔助型T細胞型態的CD4＋T細胞中會降低，而在趨向第二類輔助型T細胞型態的CD4＋T細胞中則明顯地升高。由我們的螢光素酶分析實驗 (luciferase analysis)所得到的資料中也發現，MafB和c-Maf一樣能夠顯著地增加介白素2 (IL-2)、介白素4、介白素5、介白素10、介白素12 (IL-12)及介白素13啟動子 (promoter)的活性，但對於干擾素Cytokines have been demonstrated to determine the cell fate during T helper cell differentiation. Th1 and Th2 cells separately secrete Th1 cytokine, such as IFN-γ, and Th2 cytokines, such as IL-4, IL-5, IL-10 and IL-13, and thereby promote more naïve T helper cells to differentiate into Th1 or Th2 cells. c-Maf is an IL-4-specific transcription factor in T helper cells. Upon stimulation, c-Maf is highly upregulated in Th2 cells, and can induce significant IL-4 expression to promote Th2 cell differentiation. T helper cells deficient in c-Maf result in a spontaneous bias toward the Th1 phenotype, which favors Th1-mediated diseases, such as autoimmune diabetes. Here, we demonstrate that another Maf family protein, MafB, is expressed both in in vitro- and in vivo-passaged EL4 cells upon stimulation in vitro. Moreover, the expression of MafB is downregulated in Th1-skewed CD4+ T cells, whereas it is obviously upregulated in Th2-skewed CD4+ T cells after activation. In consistent with c-Maf, MafB can significantly transactivate the activity on IL-2, IL-4, IL-5, IL-10, IL-12 and IL-13 promoters, but not on IFN-γ promoter, according to our luciferase analysis. Furthermore, CD4+ T helper cells overexpressing mafB or c-maf, through retroviral transduction, also show higher expressions of IL-4, IL-5, IL-10 and IL-13. Since MafB shows similar effects to c-Maf on cytokine regulation, an overlapping role of MafB and c-Maf in Th2 cell differentiation is suggested. However, the role of MafB in cytokine regulation and Th2 cell differentiation needs more investigation.論文口試委員審定書 ........................................................................ i 授權書 ................................................................................................ ii Acknowledgement ............................................................................. iii Abbreviations ..................................................................................... iv 摘要 .................................................................................................... v Abstract .............................................................................................. vii Table of Contents ............................................................................... viii Chapter I Introduction ….…………………………………………...... 1 Part 1 Background ...…………………………………………………………… 1 1.1 The role of T helper cells in immunity ……………………………………. 1 1.2 Factors involved in T helper cell differentiation ……………………….... 1 1.3 Th1 cell differentiation …………..………………………………………… 2 1.4 Th2 cell differentiation …………………………………………………….. 3 1.5 Mutual exclusion between Th1 and Th2 lineages ...……………………… 5 1.6 c-Maf in Th2 cell differentiation ……...…………………………………... 6 1.7 Previous studies about MafB ……………………………………………… 10 Part II Rationale & objects ……………………………………………………. 11 Carpter II Materials & Methods ………………………………….... 13 Part 1 Experiment procedures ………………………………………………... 13 2.1.1 Cell culture ……………………………………………………………….. 13 2.1.2 Constructions ………………………………………………………….…. 14 2.1.3 Luciferase assay ………………………………………………………….. 16 2.1.4 In vitro differentiation of Th cells ……………………………………….. 17 2.1.5 ELISA ...…………………………………………………………………... 18 2.1.6.1 293T cells transfection (for lentiviral production) ...…………………. 19 2.1.6.2 Lentiviral titration ...…………………………………………………… 20 2.1.6.3 Lentiviral transduction ………………………………………………... 21 2.1.7.1 293T cells transfection (for retroviral production) ……...…………… 22 2.1.7.2 Retroviral titration …………………………………………………….. 23 2.1.7.3 Retroviral transduction ………………………………………………... 23 2.1.8 Total RNA extraction …………………………………………………….. 24 2.1.9 RT-PCR and quantitative real-time PCR ………………………………. 25 Part II Experimental Materials ……………………………………………….. 29 2.2.1 Enzymes ……………………………….………………………………….. 29 2.2.2 Antibodies & Cytokines ……………….………………………………… 30 2.2.3 Kits …………….………………………………………………………….. 32 2.2.4 Chemicals, Reagents & Materials …………….………………………… 33 2.2.5 Instruments & Software …………………….…………………………… 38 2.2.6 Media, Solutions & Buffers …………………….……………………….. 40 Chapter III Results ……………………………….……………………. 44 3.1 mafB and c-maf showed distinct expression level in different organs. …. 44 3.2 mafB was significantly induced in both in vitro- and in vivo-passaged EL4 cells upon stimulation in vitro. .….……………………………………….. 45 3.3 mafB was significantly induced in Th2-skewed CD4+ T cells upon stimulation in vitro. …………………………………………………………….. 46 3.4 MafB, consistent with c-Maf, was capable of transactivating cytokine promoters in vitro. ……...……………………………………………………… 48 3.5 MafB was able to induce type 2 cytokine expression in vitro. ……………………………………………………………………………… 52 Chapter IV Discussion ……………………………………………..….. 54 4.1 Determination of the primers specific for mafB or c-maf ……………….. 54 4.2 Different distributions of mafB and c-maf in mice and in humans ……... 54 4.3 Distinct expression between mafB and c-maf in EL4 and Th2-skewed CD4+ T cells before and after stimulation ……………………………………. 56 4.4 Similar effects of MafB and c-Maf on cytokine promoters ……………... 58 4.5 Higher expression levels of type 2 cytokines in CD4+ T helper cells overexpressing mafB……………………………………………………………. 59 4.6 Future investigation of MafB in cytokine regulation and Th2 cell differentiation ………………………………………………………………….. 60 References ………………………………………….……..........…... 64 Figures & Tables …………..……………………………………….. 76en-US輔助型T細胞介白素4Th1Th2GATA3c-mafmafBIL-4[SDGs]SDG3other