Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge CB2 0QQ, UK.
Norwegian PSC Research Center, Department of Transplantation Medicine and Institute of Clinical Medicine, Oslo University Hospital and University of Oslo, 0027 Oslo, Norway.
Sci Signal. 2019 Jan 1;12(562):eaau9048. doi: 10.1126/scisignal.aau9048.
The sodium potassium pump (Na/K-ATPase) ensures the electrochemical gradient of a cell through an energy-dependent process that consumes about one-third of regenerated ATP. We report that the G protein-coupled receptor GPR35 interacted with the α chain of Na/K-ATPase and promotes its ion transport and Src signaling activity in a ligand-independent manner. Deletion of Gpr35 increased baseline Ca to maximal levels and reduced Src activation and overall metabolic activity in macrophages and intestinal epithelial cells (IECs). In contrast, a common T108M polymorphism in GPR35 was hypermorphic and had the opposite effects to Gpr35 deletion on Src activation and metabolic activity. The T108M polymorphism is associated with ulcerative colitis and primary sclerosing cholangitis, inflammatory diseases with a high cancer risk. GPR35 promoted homeostatic IEC turnover, whereas Gpr35 deletion or inhibition by a selective pepducin prevented inflammation-associated and spontaneous intestinal tumorigenesis in mice. Thus, GPR35 acts as a central signaling and metabolic pacesetter, which reveals an unexpected role of Na/K-ATPase in macrophage and IEC biology.
钠钾泵(Na/K-ATPase)通过能量依赖的过程确保细胞的电化学梯度,该过程消耗约三分之一的再生 ATP。我们报告称,G 蛋白偶联受体 GPR35 与 Na/K-ATPase 的α链相互作用,并以配体非依赖性方式促进其离子转运和Src 信号活性。Gpr35 的缺失增加了巨噬细胞和肠上皮细胞(IEC)中的基础 Ca 至最大水平,并减少了 Src 的激活和整体代谢活性。相比之下,GPR35 中的常见 T108M 多态性是超形的,对 Src 激活和代谢活性的影响与 Gpr35 缺失相反。T108M 多态性与溃疡性结肠炎和原发性硬化性胆管炎有关,这些炎症性疾病具有较高的癌症风险。GPR35 促进了 IEC 的稳态更新,而 Gpr35 的缺失或选择性 pepducin 的抑制作用可防止小鼠炎症相关和自发性肠道肿瘤发生。因此,GPR35 作为中央信号和代谢起搏细胞发挥作用,揭示了 Na/K-ATPase 在巨噬细胞和 IEC 生物学中的意外作用。