Department of Ophthalmology, Zhujiang Hospital, Southern Medical University, Guangzhou 510280, China.
Department of Ophthalmology, Liuzhou General Hospital, Liuzhou 545006, China.
Cytokine. 2019 Jul;119:175-181. doi: 10.1016/j.cyto.2019.03.019. Epub 2019 Apr 2.
The maturation state of dendritic cell (DC) plays an important role in immune activities. Previously we had found that NF-κB (p65) pathway could promote DC maturation and subsequent immune effects. But the upstream mechanism of this pathway was still unclear. Extracellular adenosine triphosphate (ATP) activating its receptor P2X7R has recently been considered as the fourth signal to activate T lymphocytes. Here we aimed to find out the connection between P2X7R and NF-κB (p65) pathway in DC maturation. Results showed that the expression of P2X7R and the intracellular ATP levels were increased along with the maturation of DC. P2X7R agonist stimulated the morphological changes of DCs into the appearance of mature DCs, and promoted the expression of NF-κB (p65), as well as the release of IFN-γ and IL-12. Whereas, P2X7R inhibitor had the opposite influences. Co-immunoprecipitation assay confirmed the binding of P2X7R and NF-κB (p65). Our study suggested that extracellular ATP could promote DC maturation and release of inflammatory cytokines through the binding of P2X7R and NF-κB (p65). This is the first study to show the P2X7R-NF-κB (p65) pathway in DC. Interference with this pathway may be able to regulate immune responses in areas like infectious diseases, inflammation, transplantation, tumor and autoimmune diseases. In addition, intracellular ATP level could be a new indicator of the maturation state of DC.
树突状细胞 (DC) 的成熟状态在免疫活动中起着重要作用。我们之前发现 NF-κB（p65）通路可以促进 DC 成熟及其后续的免疫效应。但该通路的上游机制仍不清楚。细胞外三磷酸腺苷 (ATP) 通过激活其受体 P2X7R 最近被认为是激活 T 淋巴细胞的第四信号。在这里，我们旨在寻找 P2X7R 与 DC 成熟过程中 NF-κB（p65）通路之间的联系。结果表明，P2X7R 的表达和细胞内 ATP 水平随着 DC 的成熟而增加。P2X7R 激动剂刺激 DC 形态发生变化，呈现成熟 DC 的外观，并促进 NF-κB（p65）的表达以及 IFN-γ和 IL-12 的释放。相反，P2X7R 抑制剂则有相反的影响。共免疫沉淀实验证实了 P2X7R 与 NF-κB（p65）的结合。我们的研究表明，细胞外 ATP 通过与 P2X7R 和 NF-κB（p65）的结合，促进 DC 的成熟和炎症细胞因子的释放。这是首次研究表明 P2X7R-NF-κB（p65）通路在 DC 中存在。干扰该通路可能能够调节传染病、炎症、移植、肿瘤和自身免疫性疾病等领域的免疫反应。此外，细胞内 ATP 水平可能成为 DC 成熟状态的一个新指标。
