Sir William Dunn School of Pathology, South Parks Rd, University of Oxford, Oxford, Oxfordshire, OX1 3RE, United Kingdom.
Department of Chemistry, Mansfield Rd, University of Oxford, Oxford, Oxfordshire, OX1 3TA, United Kingdom.
Eur J Pharmacol. 2023 Oct 5;956:175960. doi: 10.1016/j.ejphar.2023.175960. Epub 2023 Aug 3.
GPR84 is an orphan G-protein coupled receptor (GPCR) linked to inflammation. Strategies targeting GPR84 to prevent excessive inflammation in disease are hampered by a lack of understanding of its precise functional role. We have developed heterologous cell lines with low GPR84 expression levels that phenocopy the response of primary cells in a label-free cell electrical impedance (CEI) sensing system that measures cell morphology and adhesion. We then investigated the signalling profile and membrane localisation of GPR84 upon treatment with 6-OAU and DL-175, two agonists known to differentially influence immune cell function. When compared to 6-OAU, DL-175 was found to exhibit a delayed impedance response, a delayed and suppressed activation of Akt, which together correlated with an impaired ability to internalise GPR84 from the plasma membrane. The signalling differences were transient and occurred only at early time points in the low expressing cell lines, highlighting the importance of receptor number and kinetic readouts when evaluating signalling bias. Our findings open new ways to understand GPR84 signalling and evaluate the effect of newly developed agonists.
GPR84 是一种孤儿 G 蛋白偶联受体 (GPCR)，与炎症有关。由于缺乏对其确切功能作用的了解，针对 GPR84 预防疾病中过度炎症的策略受到了阻碍。我们开发了具有低表达水平 GPR84 的异源细胞系，这些细胞系在无标记细胞电阻抗 (CEI) 传感系统中模拟了原代细胞的反应，该系统可测量细胞形态和黏附性。然后，我们研究了 GPR84 在 6-OAU 和 DL-175 两种已知可不同程度影响免疫细胞功能的激动剂处理后的信号特征和膜定位。与 6-OAU 相比，发现 DL-175 表现出延迟的阻抗反应、延迟和抑制的 Akt 激活，这与从质膜内化 GPR84 的能力受损有关。这些信号差异是短暂的，仅在低表达细胞系的早期时间点发生，这突出了在评估信号偏倚时受体数量和动力学读数的重要性。我们的发现为理解 GPR84 信号和评估新开发激动剂的效果开辟了新途径。
