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

在本研究项目中，首次尝试使用尾部截短的Notch配体来建立控制T淋巴细胞功能的系统，因为这种突变的分子调节果蝇的发育。不幸的是，尽管产生了各种截尾的Notch配体基因并进行了分析，但尝试失败了。接下来，我们完成了以下两个项目：(1)研究疯狂边缘在T细胞发育中的作用，它通过Notch分子的糖基化来调节Notch信号；(2)检测Notch/Notch配体对NK细胞激活和功能的影响。胸腺细胞表达Lfng可促进未成熟CD8SP细胞的发育，但抑制成熟的CD4SP和CD8SP细胞的发育。相反，由于缺失…，胸腺细胞中LFNG的下调抑制了DP细胞的发育肾小管上皮细胞分化程度较高。Lfng在胎肝来源的造血干细胞中的过表达促进了T细胞的发育，而其下调抑制了T细胞的发育。上述结果提示，Ling在糖尿病肾病细胞中的高表达可能通过增强Notch信号转导途径促进T细胞分化。(2)Jagged2基因在A20肿瘤细胞上的表达增强抑制了A20肿瘤细胞的体内生长，这种抑制作用可被NK细胞耗尽所抑制。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对NK细胞的刺激直接增强了其细胞毒作用、干扰素-γ的产生和增殖。在MC细胞上连接Notch2可增强其细胞毒活性，这种作用可被一种伽马分泌酶抑制剂抑制。这些结果表明Jagged2-Notch轴在DC介导的MC细胞杀伤中起重要作用。此外，对这种相互作用的操纵可能提供一种诱导强大的肿瘤免疫的方法。

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