Establishment of the system to control T lymphocyte functions using Notch ligands

在本研究项目中，由于这种突变分子可以调节果蝇的发育，我们首次尝试使用尾截断的Notch配体来建立控制T淋巴细胞功能的系统。不幸的是，尽管产生了各种尾截断的Notch配体基因结构并进行了分析，但该尝试失败了。接下来，我们进行了以下两个项目：(1)研究通过Notch分子糖基化调节Notch信号通路的lunatic - fringe在T细胞发育中的作用；(2)研究Notch/Notch配体对NK细胞活化和功能的影响。(1) Jurkat T细胞中过表达lng增强了Notch信号，表明lng是T细胞中Notch信号的正调节因子。胸腺细胞中lng的强化表达促进了未成熟CD8SP细胞的发育，但抑制了成熟CD4SP和CD8SP细胞的发育。相比之下，胸腺细胞中lgf的下调抑制了DP细胞的发育，这是由于DN细胞阶段缺乏更有效的分化。lng在胎儿肝源性造血干细胞中的过表达促进了T细胞的发育，而其下调则抑制了T细胞的发育。这些结果表明，Ling在DN细胞中的高表达通过加强Notch信号传导来促进T细胞分化。(2)在A20肿瘤细胞上强制表达Jagged2会抑制肿瘤细胞的生长，这种抑制作用通过消耗NK细胞而被消除。同样，A20细胞与过表达jagged2的DC共接种可抑制小鼠A20细胞的生长。Jagged2刺激NK细胞直接增强其细胞毒性、ifn - γ产生和增殖。Notch2在MC细胞上的连接增强了它们的细胞毒活性，而这种活性被γ分泌酶抑制剂抑制。这些结果表明Jagged2-Notch轴在dc介导的MC细胞毒性中起着至关重要的作用。此外，操纵这种相互作用可能提供一种诱导强效肿瘤免疫的方法。sp少

In this research project, the first attempt to establish the system to control T lymphocyte function was done using tail-truncated Notch ligands because such mutanted molecules modulate fruit fly development. Unfortunately, the attempt was failed despite various constructs of tail-truncated Notch ligand genes were produced and then assayed. Nextly, the following two projects were performed : (1) to study a role of lunatic fringe, which modulate Notch-signaling by glycosylation of Notch molecules, in T cell development and (2) to examine effects of Notch/Notch ligands on NK cell activation and fuction.(1)Overexpression of Lfng in Jurkat T cells strengthened Notch signaling, indicating that Lfng is a positive regulator for Notch signaling in T cells. The enforced expression of Lfng in thymocytes enhanced the development of immature CD8SP cells but decreased mature CD4SP and CD8SP cells. In contrast, the down-regulation of Lfng in thymocytes suppressed DP cell development due to the defec … More tive diffentiation in DN cell stage. The overexpression of Lfng in fetal liver-derived hemopoietic stem cells enhanced T cell development, whereas its down-regulation suppressed it. These results suggest that the high expression of Ling in DN cells contributes to enhance T cell differentiation through strengthening Notch signaling.(2)Enforced expression of Jagged2 on A20 tumor cells suppressed their growth in vivo, which was abrogated by depleting NK cells. Consistently, coinoculation of A20 cells with DC overexpressing Jagged2suppressed the growth of A20 cells in mice. Stimulation of NK cells with Jagged2 directly enhanced their cytotoxicity, IFN-gamma production, and proliferation. Ligation of Notch2 on MC cells enhanced their cytotoxic activity, which was suppressed by a gamma-secretase inhibitor. These results indicate that the Jagged2-Notch axis plays a crucial role in DC-mediated MC cell cytotoxicity. Furthermore, manipulation of this interaction may provide an approach to induce potent tumor immunity.sp Less