Müller Tobias, Bayer Hans, Myrtek Daniel, Ferrari Davide, Sorichter Stephan, Ziegenhagen Manfred W, Zissel Gernot, Virchow J Christian, Luttmann Werner, Norgauer Johannes, Di Virgilio Francesco, Idzko Marco
Department of Pneumology, University Medical Clinic, University of Freiburg, D-79104 Freiburg i. Br., Germany.
Am J Respir Cell Mol Biol. 2005 Dec;33(6):601-9. doi: 10.1165/rcmb.2005-0181OC. Epub 2005 Aug 18.
Uridine nucleotides and UDP-glucose are endogenous molecules, which are released into the extracellular environment in a lytic manner after cell damage, as well as by regulated nonlytic mechanisms. Recently, a UDP-glucose-specific G(i) protein-coupled P2Y receptor, namely P2Y(14), has been cloned. In this study, we demonstrated expression of the P2Y(14) mRNA in human lung epithelial cells and in the epithelial cell lines A549 and BEAS-2B. Evidence of functional expression of the P2Y(14) receptor in these cell lines was provided by calcium measurements after stimulation with uridine 5'-diphosphoglucose (UDP-glc). Experiments with pertussis toxin and the Ca(2+)-chelator EGTA revealed participation of pertussis toxin-sensitive G(i/o)-proteins in the mobilization of Ca(2+)-ions from intracellular stores by UDP-glc. Moreover, UDP-glc increased secretion of the potent neutrophil chemoattractant CXCL8/IL-8 in A549 and BEAS-2B cells in a pertussis toxin-sensitive manner. Moreover, reverse transcription and quantitative polymerase chain reaction revealed that UDP-glc modulated mRNA levels of IL-8/CXCL8. However, stimulation of A549 and BEAS-2B cells with UDP-glc neither modified basal nor cytokine-induced secretion of the CXC-chemokines CXCL9/MIG, CXCL10/IP-10, and CXCL11/I-TAC. In addition, UDP-glc did not affect proliferation of the two cell lines. In summary, our data provide evidence for a distinct physiologic role of P2Y(14) in the selective release of specific chemokines from human airway epithelial cells.
尿苷核苷酸和UDP-葡萄糖是内源性分子，在细胞损伤后以溶解方式释放到细胞外环境中，也可通过调节性非溶解机制释放。最近，一种UDP-葡萄糖特异性G(i)蛋白偶联P2Y受体，即P2Y(14)，已被克隆。在本研究中，我们证明了P2Y(14) mRNA在人肺上皮细胞以及上皮细胞系A549和BEAS-2B中的表达。在用5'-二磷酸葡萄糖（UDP-葡萄糖）刺激后通过钙测量提供了这些细胞系中P2Y(14)受体功能表达的证据。用百日咳毒素和Ca(2+)螯合剂EGTA进行的实验揭示了百日咳毒素敏感的G(i/o)蛋白参与UDP-葡萄糖从细胞内储存中动员Ca(2+)离子。此外，UDP-葡萄糖以百日咳毒素敏感的方式增加了A549和BEAS-2B细胞中强效中性粒细胞趋化因子CXCL8/IL-8的分泌。此外，逆转录和定量聚合酶链反应显示UDP-葡萄糖调节IL-8/CXCL8的mRNA水平。然而，用UDP-葡萄糖刺激A549和BEAS-2B细胞既不改变基础分泌也不改变细胞因子诱导的CXC趋化因子CXCL9/MIG、CXCL10/IP-10和CXCL11/I-TAC的分泌。此外，UDP-葡萄糖不影响这两种细胞系的增殖。总之，我们的数据为P2Y(14)在人呼吸道上皮细胞中选择性释放特定趋化因子方面的独特生理作用提供了证据。
