DataSheet_1_Lysine methyltransferase Kmt2d regulates naive CD8+ T cell activation-induced survival.pdf

Lysine specific methyltransferase 2D (Kmt2d) catalyzes the mono-methylation of histone 3 lysine 4 (H3K4me1) and plays a critical role in regulatory T cell generation via modulating Foxp3 gene expression. Here we report a role of Kmt2d in naïve CD8+ T cell generation and survival. In the absence of Kmt2d, the number of CD8+ T cells, particularly naïve CD8+ T cells (CD62Lhi/CD44lo), in spleen was greatly decreased and in vitro activation-related death significantly increased from Kmt2dfl/flCD4cre+ (KO) compared to Kmt2dfl/flCD4cre- (WT) mice. Furthermore, analyses by ChIPseq, RNAseq, and scRNAseq showed reduced H3K4me1 levels in enhancers and reduced expression of apoptosis-related genes in activated naïve CD8+ T cells in the absence of Kmt2d. Finally, we confirmed the activation-induced death of antigen-specific naïve CD8+ T cells in vivo in Kmt2d KO mice upon challenge with Listeria monocytogenes infection. These findings reveal that Kmt2d regulates activation-induced naïve CD8+ T cell survival via modulating H3K4me1 levels in enhancer regions of apoptosis and immune function-related genes.

赖氨酸特异性甲基转移酶2D（Kmt2d）可催化组蛋白3赖氨酸4发生单甲基化修饰（H3K4me1），并通过调控Foxp3基因的表达在调节性T细胞生成过程中发挥关键作用。本研究报道了Kmt2d在初始CD8+ T细胞生成与存活中的功能。与Kmt2dfl/flCD4cre-野生型（WT）小鼠相比，Kmt2dfl/flCD4cre+基因敲除型（KO）小鼠的脾脏CD8+ T细胞总数显著降低，尤其是初始CD8+ T细胞（CD62L高表达/CD44低表达亚群），且其体外激活相关的细胞死亡水平显著升高。进一步通过染色质免疫共沉淀测序（ChIP-seq）、RNA测序（RNA-seq）及单细胞RNA测序（scRNA-seq）分析发现，在缺失Kmt2d的激活初始CD8+ T细胞中，增强子区域的H3K4me1修饰水平以及凋亡相关基因的表达均出现下调。最后，本研究通过单核细胞增生李斯特菌感染攻毒实验，在体内验证了Kmt2d基因敲除小鼠中抗原特异性初始CD8+ T细胞的激活诱导性死亡现象。综上，Kmt2d可通过调控凋亡与免疫功能相关基因增强子区域的H3K4me1修饰水平，进而调控激活诱导的初始CD8+ T细胞存活。