Systems approach reveals distinct and shared signaling networks of the four PGE2 receptors in T cells
The lipid mediator PGE2 suppresses antitumor immunity by activating its four related GPCRs on T cells. Lone et al. used quantitative phosphoproteomics and phosphoflow cytometry to analyze downstream signaling elicited by the stimulation of all receptors simultaneously or individually in different T cell subsets. The analysis revealed G protein–dependent and G protein–independent pathways that were activated by each receptor in all T cells, as well as pathways that were activated by only a subset of receptors, in only a subset of cells, or with receptor-specific kinetics. Network modeling predicted mechanisms of cross-talk and signal integration downstream of the receptors. These data are a comprehensive resource for future explorations of the functional consequences of PGE2 receptor–specific signaling in immune homeostasis, inflammation, and tumor-associated immunosuppression.
脂质介质 PGE 2通过激活 T 细胞上的四个相关 GPCR 来抑制抗肿瘤免疫。孤独等人。使用定量磷酸化蛋白质组学和磷酸化流式细胞术来分析在不同 T 细胞亚群中同时或单独刺激所有受体引起的下游信号传导。分析揭示了由所有 T 细胞中的每个受体激活的 G 蛋白依赖性和 G 蛋白非依赖性通路，以及仅由一部分受体激活、仅在一部分细胞中或具有受体特异性的通路。动力学。网络建模预测了受体下游串扰和信号整合的机制。这些数据是未来探索 PGE 功能后果的综合资源2免疫稳态、炎症和肿瘤相关免疫抑制中的受体特异性信号传导。
Prostaglandin E2 (PGE2) promotes an immunosuppressive microenvironment in cancer, partly by signaling through four receptors (EP1, EP2, EP3, and EP4) on T cells. Here, we comprehensively characterized PGE2 signaling networks in helper, cytotoxic, and regulatory T cells using a phosphoproteomics and phosphoflow cytometry approach. We identified ~1500 PGE2-regulated phosphosites and several important EP1–4 signaling nodes, including PKC, CK2, PKA, PI3K, and Src. T cell subtypes exhibited distinct signaling pathways, with the strongest signaling in EP2-stimulated CD8+ cells. EP2 and EP4, both of which signal through Gαs, induced similar signaling outputs, but with distinct kinetics and intensity. Functional predictions from the observed phosphosite changes revealed PGE2 regulation of key cellular and immunological processes. Last, network modeling suggested signal integration between the receptors and a substantial contribution from G protein–independent signaling. This study offers a comprehensive view of the different PGE2-regulated phosphoproteomes in T cell subsets, providing a valuable resource for further research on this physiologically and pathophysiologically important signaling system.
前列腺素 E 2 (PGE 2 ) 在癌症中促进免疫抑制微环境，部分是通过T 细胞上的四种受体（EP 1、EP 2、EP 3和 EP 4）传递信号。在这里，我们使用磷酸蛋白质组学和磷酸流式细胞术方法全面表征了辅助性、细胞毒性和调节性 T 细胞中的PGE 2信号网络。我们鉴定了约 1500 个 PGE 2调节的磷酸位点和几个重要的 EP 1-4信号节点，包括 PKC、CK2、PKA、PI3K 和 Src。T 细胞亚型表现出不同的信号通路，在 EP 2刺激的 CD8 + 中信号最强细胞。EP 2和EP 4均通过G αs发出信号，诱导类似的信号输出，但具有不同的动力学和强度。观察到的磷位点变化的功能预测揭示了 PGE 2对关键细胞和免疫过程的调节。最后，网络建模表明受体之间的信号整合和 G 蛋白非依赖性信号传导的重要贡献。这项研究提供了T 细胞亚群中不同 PGE 2调节的磷酸化蛋白质组的综合视图，为进一步研究这种在生理和病理生理上具有重要意义的信号系统提供了宝贵的资源。