EGFR-HIF1a signaling positively regulates the differentiation of IL-9 producing T helper cells

Interleukin 9 (IL-9)-producing helper T (Th9) cells are essential for inducing anti-tumor immunity and inflammation in allergic and autoimmune diseases. Although transcription factors that are essential for Th9 cell differentiation have been identified, other signaling pathways that are required for their generation and functions are yet to be found. Here we identified that Epidermal Growth Factor Receptor (EGFR) is essential for IL-9 induction in Th cells. Moreover, amphiregulin (Areg), an EGFR ligand, is critical for the amplification of Th9 cells induced by TGF-ß1 and IL-4. Furthermore, our data show that AREG-EGFR signaling induces HIF1a, which binds and transactivates IL-9, IRF4 and NOS2 promoters in Th9 cells. Loss of EGFR or HIF1a abrogates Th9 cell differentiation and suppress their anti-tumor functions. Moreover, in line with its reliance on HIF1a expression, metabolomics profiling of Th9 cells revealed that succinate, a TCA cycle metabolite, promotes Th9 cell differentiation and Th9 cell-mediated tumor regression. Overall design: RNASeq analysis of Th9 cells from WT and Areg-/- mice.

产生白细胞介素9（Interleukin 9，IL-9）的辅助性T细胞（Th9）在诱导抗肿瘤免疫以及过敏性与自身免疫性疾病的炎症反应过程中发挥关键作用。尽管目前已明确调控Th9细胞分化的核心转录因子，但参与其生成与功能发挥的其他信号通路仍有待发掘。本研究证实，表皮生长因子受体（Epidermal Growth Factor Receptor，EGFR）对于T细胞中IL-9的诱导表达至关重要。进一步研究发现，双调蛋白（amphiregulin，Areg）作为EGFR的配体，可显著扩增转化生长因子β1（TGF-β1）与白细胞介素4（IL-4）诱导的Th9细胞群体。此外，本研究数据表明，AREG-EGFR信号通路可诱导缺氧诱导因子1α（Hypoxia-inducible Factor 1α，HIF1α）的表达，后者可结合并反式激活Th9细胞中IL-9、干扰素调节因子4（Interferon Regulatory Factor 4，IRF4）及诱导型一氧化氮合酶（Inducible Nitric Oxide Synthase，NOS2）的启动子区域。敲除EGFR或HIF1α可完全阻断Th9细胞的分化，并抑制其抗肿瘤功能。同时，鉴于Th9细胞的功能依赖于HIF1α的表达，对Th9细胞的代谢组学分析显示，三羧酸循环代谢产物琥珀酸可促进Th9细胞分化，并增强Th9细胞介导的肿瘤消退效应。本研究的整体实验设计：对野生型（Wild Type，WT）与Areg基因敲除（Areg-/-）小鼠来源的Th9细胞开展RNA测序（RNA-seq）分析。