Evaluate the Role and Mechanism of GPR4 in Immunotherapy-Related Colitis

项目摘要 针对免疫检查点的癌症免疫治疗，如PD-1(程序性细胞死亡1)/PD-L1 (程序性死亡配体1)和CTLA-4(细胞毒性T淋巴细胞相关蛋白4)，导致了 在一些癌症患者中具有显著的抗肿瘤作用和总体生存改善。由于过度- 激活免疫系统，然而，癌症免疫治疗也可能导致轻度到重度和 有时会发生危及生命的免疫相关不良事件(IrAE)。炎症性疾病的常见类型 自身免疫性肠炎包括结肠炎/腹泻、肝炎、肺炎、甲状腺炎和其他炎症性疾病。 并发症。这些irAEs可导致严重的发病率和治疗中断。生物学 然而，癌症免疫治疗后患者易患irAEs的因素尚未得到很好的证实。 皮质类固醇和其他免疫抑制药物通常用于治疗irAEs，但 一些患者对这些治疗方法难以抗拒。此外，全身性免疫抑制与 免疫抑制药物可能会干扰免疫疗法的抗癌效果，也可能会 面临肺炎等机会性感染风险的患者。因此，重要的是更好地 了解irAEs的机制，并开发管理irAEs的新方法。 虽然大多数IRAE研究集中在免疫细胞和炎性细胞因子上，但这个项目的目的是 询问血管和白细胞之间的界面。质子传感G蛋白偶联 受体4(GPR4)在血管内皮细胞中高表达，在血管内皮细胞中起着守门人的作用。 通过调节白细胞与内皮细胞的相互作用来实现炎症反应。我们最近的研究 GPR4的激活可刺激多种炎症基因的表达 内皮细胞(ECs)，并增加白细胞与EC的黏附。有趣的是，GPR4的基因表达是 溃疡性结肠炎和克罗恩病的炎性肠组织中增加了约5倍 与未发炎的肠道组织相比。抑制GPR4具有抗炎、抗炎作用 具有伤害性和抗血管生成作用。然而，GPR4在irAEs和iAEs中的作用和机制 癌症免疫疗法还没有被研究过。 在本项目中，我们将研究GPR4在肿瘤免疫治疗和irAEs中的作用和机制。 将利用GPR4基因敲除小鼠和GPR4拮抗剂在体内解开GPR4的功能。老鼠 将用抗CTLA-4/抗PD-1免疫疗法联合GPR4治疗黑色素瘤 抑制力。利用小鼠模型，我们将(1)确定GPR4在 免疫治疗相关的结肠炎和其他irAEs；(2)阐明GPR4阻断的抗癌作用 免疫疗法。

Project Summary Cancer immunotherapy targeting the immune checkpoints, such as PD-1 (programmed cell death 1)/PD-L1 (programmed death-ligand 1) and CTLA-4 (cytotoxic T lymphocyte associated protein 4), has led to significant anti-tumor effects and overall survival improvement in some cancer patients. Due to hyper- activation of the immune system, however, cancer immunotherapy may also cause mild-to-severe and sometimes life-threatening immune-related adverse events (irAEs). The commons types of inflammatory and autoimmune irAEs include colitis/diarrhea, hepatitis, pneumonitis, thyroiditis, and other inflammatory complications. These irAEs can result in significant morbidity and treatment discontinuation. Biological factors that predispose patients to irAEs after cancer immunotherapy, however, are not well established. Corticosteroids and other immunosuppressive drugs are typically used for the management of irAEs, but some patients are refractory to these treatments. Moreover, systemic immunosuppression associated with immunosuppressive drugs may interfere with the anti-cancer effects of immunotherapy and may also place patients at risk for opportunistic infections such as pneumonia. It is, therefore, important to better understand the mechanisms of irAEs and to develop novel approaches for the management of irAEs. While most irAE research focuses on immune cells and inflammatory cytokines, this project is aimed to interrogate the interface between blood vessels and leukocytes. The proton-sensing G-protein-coupled receptor 4 (GPR4) is highly expressed in vascular endothelial cells and functions as a “gatekeeper” during inflammatory responses via regulating the leukocyte-endothelium interaction. Our recent studies demonstrate that activation of GPR4 stimulates the expression of numerous inflammatory genes in endothelial cells (ECs) and increases leukocyte-EC adhesion. Interestingly, the gene expression of GPR4 is increased by about 5-fold in the inflamed intestinal tissues of ulcerative colitis and Crohn's disease samples when compared to the non-inflamed intestinal tissues. Inhibition of GPR4 has anti-inflammatory, anti- nociceptive, and anti-angiogenic effects. However, the function and mechanism of GPR4 in irAEs and cancer immunotherapy have not been studied. In this project, we will investigate the role and mechanism of GPR4 in cancer immunotherapy and irAEs. GPR4 knockout mice and GPR4 antagonist will be employed to unravel the function of GPR4 in vivo. Mice with melanoma will be treated with anti-CTLA-4/anti-PD-1 immunotherapy in combination with GPR4 inhibition. Using the mouse model, we will (1) determine the role and mechanism of GPR4 in immunotherapy-related colitis and other irAEs; (2) elucidate the effects of GPR4 blockade on anti-cancer immunotherapy.