结直肠癌中YAP通过调控糖酵解促进Treg免疫抑制功能的机制研究

In colorectal cancer, regulatory T cells (Treg) are closely related to the response rate of immunotherapy. YAP promotes Treg differentiation and maintenance of immune function, but the mechanism is still unknown. We found that YAP expression of Treg in colorectal cancer is higher than that of healthy people; downregulated YAP could enhance the ability of suppressing CD8+ T cells, which could be partially rescued by HIF1α activator DMOG. We hypothesized that YAP could increase the immunosuppression of Treg on CD8+ T cells by up-regulating glycolytic key enzymes in the microenvironment of colorectal cancer. On this basis, we planned to: first, explore the relationship between YAP expression level or metabolic profile of Treg and clinical prognosis of colorectal cancer patients; Second, confirm the role of YAP in Treg immunosuppressive function and glycolysis in vivo; Third, find out the specific molecular mechanism of how YAP promotes Treg glycolytic key enzymes in vitro. Then, we will clarify the role of YAP in the metabolic pathway and immune function of Treg in the microenvironment of colorectal cancer. It will provide a theoretical basis for finding new metabolic checkpoints of immunotherapy.

结直肠癌中调节性T细胞（Treg）与免疫治疗疗效密切相关。YAP可促进Treg免疫抑制功能的维持，但其机制尚不明确。我们首次发现：结直肠癌Treg中YAP和糖酵解关键酶基因表达量均升高；下调Treg中YAP将减弱其对CD8+T细胞的抑制能力，而该作用可被HIF1α激活剂DMOG部分抵消。我们提出假设：结直肠癌中，YAP可通过上调糖酵解基因表达提高Treg对CD8+T细胞的抑制作用。本项目拟进行：一、结直肠癌患者外周血和肿瘤组织中，Treg的YAP表达水平、代谢谱的差异以及与临床预后的关系；二、在整体动物水平探究YAP对Treg免疫抑制功能和糖酵解的作用；三、在细胞水平探索YAP促进Treg糖酵解基因表达的分子机制。据此，我们将明确结直肠癌微环境中，YAP对Treg代谢途径和免疫功能的作用及其分子机制，为寻找新的结直肠癌免疫治疗代谢检查点提供理论依据。

结直肠癌是严重威胁人类健康和生命的恶性肿瘤之一。既往临床研究显示，结直肠癌患者对PD-1免疫治疗的反应率不高且存在较大差异，结直肠癌中调节性T细胞（Treg）与免疫治疗疗效密切相关。YAP可促进Treg免疫抑制功能的维持，但其机制尚不明确。.本项目研究内容主要包括：一、结直肠癌患者外周血和肿瘤组织中，Treg的YAP表达水平、代谢谱的差异以及与临床预后的关系；二、在整体动物水平探究YAP对Treg免疫抑制功能和糖酵解的作用；三、在细胞水平探索YAP促进Treg糖酵解基因表达的分子机制。.目前主要结果是： 结直肠癌患者外周血中，YAPhighTreg明显升高，且糖酵解关键酶基因(HK2、PFK1)表达水平明显升高； 成功构建Treg特异性敲除小鼠的AOM/DSS结直肠癌模型， YAPflox/floxFoxp3Cre+Treg糖酵解关键酶基因(Hk2、 Gpi、Pfk1、Pkm2、Eno1、Tpi)表达升高；YAP通过SREBP2调控结直肠癌细胞的胆固醇代谢。.据此，我们证明了结直肠癌微环境中，YAP对Treg代谢途径和免疫功能的存在抑制作用作用，为寻找新的结直肠癌免疫治疗代谢检查点提供理论依据。