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），已经导致 在某些癌症患者中具有显著的抗肿瘤作用和总生存期改善。由于超- 然而，癌症免疫疗法也可能引起轻度至重度的癌症， 有时危及生命的免疫相关不良事件（irAE）。常见的炎症类型 自身免疫性irAE包括结肠炎/腹泻、肝炎、肺炎、甲状腺炎和其他炎性疾病。 并发症这些irAE可导致严重发病和治疗中止。生物 然而，使患者在癌症免疫治疗后易患irAE的因素尚未完全确定。 皮质类固醇和其他免疫抑制药物通常用于irAE的管理，但 一些患者对这些治疗是难治的。此外，全身免疫抑制与 免疫抑制药物可能会干扰免疫疗法的抗癌效果， 有机会性感染风险的患者，如肺炎。因此，重要的是要更好地 了解irAE的机制，并开发管理irAE的新方法。 虽然大多数irAE研究集中在免疫细胞和炎症细胞因子，但该项目旨在 询问血管和白细胞之间的界面。质子敏感G蛋白偶联 受体4（GPR 4）在血管内皮细胞中高度表达，并在血管内皮细胞生长过程中起“看门人”的作用。 通过调节白细胞-内皮细胞相互作用的炎症反应。我们最近的研究 这表明GPR 4的激活刺激了许多炎症基因的表达， 内皮细胞（EC）和增加白细胞EC粘附。有趣的是，GPR 4的基因表达是 在溃疡性结肠炎和克罗恩病样本的炎症肠道组织中增加约5倍 与未发炎的肠组织相比。GPR 4的抑制具有抗炎、抗肿瘤、抗炎和抗肿瘤作用。 伤害感受和抗血管生成作用。然而，GPR 4在irAE中的功能和机制以及 癌症免疫疗法尚未被研究。 在本项目中，我们将研究GPR 4在癌症免疫治疗和irAE中的作用和机制。 GPR 4基因敲除小鼠和GPR 4拮抗剂将用于阐明GPR 4在体内的功能。小鼠 将用抗CTLA-4/抗PD-1免疫疗法联合GPR 4治疗黑色素瘤 抑制作用使用小鼠模型，我们将（1）确定GPR 4在 免疫治疗相关结肠炎和其他irAE;（2）阐明GPR 4阻断对抗癌的影响 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.