Single-cell RNA sequencing reveals the novel role of Ezh2 in NK cell maturation and function

Our previous work indicated that the Enhancer of Zeste Homolog 2 (Ezh2) is a negative regulator of NK cell early differentiation and function by trimethylation of histone H3 lysine 27 (H3K27me3). Here, we deleted Ezh2 from immature NK and downstream progeny to explore its role in NK cell maturation by single-cell RNA sequencing (scRNA-seq). We identified six distinct NK stages based on transcriptional signature during the maturation of NK cells. Conditional deletion of Ezh2 in NK cells resulted in the maturation trajectory of NK cell arrested in CD11b SP stage 5 which is clustered with genes related to activating function of NK cells. Mechanistically, we speculated that Ezh2 plays a critical role in NK development by activating gene expression of the AP-1 superfamily independent of PRC2 function. Our results implied a novel role for the Ezh2-AP-1-Klrg1 axis to alter NK cell maturation trajectory and NK cell-mediated cytotoxicity. Overall design: single-cell RNA seq of spleen NK cells from 6~8 week old wild type (WT) and Ezh2?NK mice

我们此前的研究表明，zeste同源增强子2（Enhancer of Zeste Homolog 2，Ezh2）可通过对组蛋白H3赖氨酸27进行三甲基化修饰（H3K27me3），负调控自然杀伤细胞（natural killer cell，NK细胞）的早期分化与功能。本研究中，我们对未成熟NK细胞及其下游子代细胞中的Ezh2进行条件性敲除，结合单细胞RNA测序（single-cell RNA sequencing，scRNA-seq）探究其在NK细胞成熟过程中的作用。我们基于NK细胞成熟过程中的转录特征，鉴定出6个不同的NK细胞阶段。NK细胞中条件性敲除Ezh2会导致NK细胞的成熟轨迹阻滞于CD11b单阳性（CD11b SP）第5阶段，该阶段的基因表达特征与NK细胞活化功能相关。从机制层面分析，我们推测Ezh2可不依赖于多梳抑制复合体2（polycomb repressive complex 2，PRC2）的功能，通过激活AP-1超家族的基因表达，在NK细胞发育过程中发挥关键作用。我们的研究结果揭示了Ezh2-AP-1-Klrg1轴调控NK细胞成熟轨迹以及NK细胞介导的细胞毒性的全新功能。总体实验设计：采集6~8周龄野生型（wild type，WT）小鼠与Ezh2?NK小鼠的脾脏NK细胞，进行单细胞RNA测序。