TCF-1和LEF-1调控CD8+ T细胞免疫应答的分子机制研究

Our previous work demonstrated TCF-1 plays a role in CD8+ T-cell response, but the mechanisms are unclear. To avoid the compensation from LEF-1, another downstream transcription factor of canonical Wnt pathway, double knockout mice of TCF-1 and LEF-1 driven by CD4Cre were used. Our data showed double deficient CD8+ T cells could not expand after LM-Ova infection in vivo, nor TCR stimulation in vitro. Comparing to WT cells, double ablated cells exhibited higher Ca2+-NFAT signaling activation upon TCR stimulation in vitro, which is consistent with anergic CD8+ T cells. ChIP-Seq data showed TCF-1 bound directly to Cd28, Cblb, and Dtx1 loci, key genes associated with T-cell activation and anergy. However, the preliminary data revealed that the excision of Lef1 by CD4Cre was less than half. Since the recombination by ERT2Cre was more efficient, the new mice model, double conditional knockout driven by ERT2Cre have been choosen to study the mechanisms of TCF-1 and LEF-1 in regulating CD8+ T-cell response. This research will shed new light on providing novel strategies and targets against the diseases caused by dysregulation of CD8+ T cells.

我们已报道TCF-1参与了CD8+ T细胞免疫应答的调控，但其分子机制还不清楚。为避免LEF-1的代偿作用，我们使用CD4Cre介导的TCF-1和LEF-1双敲除小鼠对其调控CD8+ T细胞免疫应答的分子机制展开研究。我们发现双敲除的CD8+ T细胞在体内外都丧失了扩展能力。体外实验表明双敲除与失能的细胞一样都增强了Ca2+-NFAT信号的活化。ChIP-Seq数据表明TCF-1在T细胞活化和失能的关键基因Cd28、Cblb、Dtx1上都有结合区域。但CD4Cre介导的Lef1的剪切不到一半，不能用于进一步研究。因此，本项目拟使用剪切效率更高的ERT2Cre来介导双条件敲除小鼠并从效应细胞的扩展、TCR信号的转导、免疫应答的调控网络等方面来深入研究TCF-1和LEF-1调控CD8+ T细胞免疫应答的分子机制。本项目的研究成果将为治疗CD8+ T细胞失调引起的各种疾病提供新思路和新靶点。

我们已报道TCF-1参与了CD8+ T细胞免疫应答的调控，但其分子机制还不清楚。为避免LEF-1的代偿作用，我们使用CD4Cre介导的TCF-1和LEF-1双敲除小鼠对其调控CD8+ T细胞免疫应答的分子机制展开研究。我们发现双敲除的CD8+ T细胞在体内外都丧失了扩展能力。体外实验表明双敲除与失能的细胞一样都增强了Ca2+-NFAT信号的活化。ChIP-Seq数据表明TCF-1在T细胞活化和失能的关键基因Cd28、Cblb、Dtx1上都有结合区域。但CD4Cre介导的Lef1的剪切不到一半，不能用于进一步研究。因此，本项目拟使用剪切效率更高的ERT2Cre来介导双条件敲除小鼠并从效应细胞的扩展、TCR信号的转导、免疫应答的调控网络等方面来深入研究TCF-1和LEF-1调控CD8+ T细胞免疫应答的分子机制。本项目的研究成果将为治疗CD8+ T细胞失调引起的各种疾病提供新思路和新靶点。