An important mediator of inflammation is prostaglandin E₂ (PGE₂), whose levels are determined by the activity of the enzyme cyclooxygenase (COX). Of the two isoforms of the enzyme, COX-2 has been shown to be induced in macrophages during inflammation. Although general COX inhibitors, belonging to the class of nonsteroidal anti-inflammatory drugs, or specific COX-2 inhibitors, called coxibs, are useful in the control of acute inflammation, adverse reactions were seen when used chronically in the treatment of rheumatoid arthritis or neurodegenerative diseases. Extracellular ATP (eATP) has been reported as a damage-associated molecular pattern signal. In this report, we show that eATP synergistically increases the levels of COX-2 enzyme and PGE₂ in LPS-activated RAW264.7 macrophages and human monocytes. Activation of macrophages also occurred when cultured in media obtained from dying neurons that contained higher levels of ATP. We show that eATP increases the levels of COX-2 protein, which is sustained up to 36 h poststimulation. This is in turn due to sustained levels of phosphorylated, or activated, cyclin-dependent kinase 9 and p38 MAPK in ATP-treated cells compared to LPS-stimulated cells. The eATP-dependent increase in COX-2/PGE₂ levels in LPS-activated RAW264.7 cells could be abolished using antagonists for purinergic P2X7 -and P2Y6 receptors. Similarly, the increase in COX-2/PGE₂ levels in the peritoneum of LPS-treated mice could be significantly abolished in mice that were preinjected with the nonspecific P2 receptor antagonist, suramin. P2 receptor antagonists, therefore, should be explored in our search for an ideal anti-inflammatory candidate.

中文翻译：

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外源性 ATP 通过 CDK9 和 p38 MAPK 的持续磷酸化调节巨噬细胞中 PGE2 的释放

炎症的一个重要介质是前列腺素 E ₂ (PGE ₂ )，其水平由环氧合酶 (COX) 的活性决定。在该酶的两种同工型中，COX-2 已被证明在炎症期间在巨噬细胞中被诱导。虽然属于非甾体抗炎药的一般 COX 抑制剂或称为 coxib 的特定 COX-2 抑制剂可用于控制急性炎症，但长期用于治疗类风湿性关节炎或神经退行性疾病时会出现不良反应。疾病。细胞外 ATP (eATP) 已被报道为与损伤相关的分子模式信号。在本报告中，我们展示了 eATP 协同增加 COX-2 酶和 PGE _{2 的水平}在 LPS 激活的 RAW264.7 巨噬细胞和人类单核细胞中。当在从死亡神经元获得的培养基中培养时，巨噬细胞也会被激活，这些神经元含有更高水平的 ATP。我们表明 eATP 增加了 COX-2 蛋白的水平，该水平在刺激后 36 小时内持续存在。这又是由于与 LPS 刺激的细胞相比，ATP 处理的细胞中磷酸化或活化的细胞周期蛋白依赖性激酶 9 和 p38 MAPK 的持续水平。使用嘌呤能 P2X7 和 P2Y6 受体的拮抗剂可以消除 LPS 激活的 RAW264.7 细胞中 COX-2/PGE ₂水平的 eATP 依赖性增加。同样，COX-2/PGE ₂的增加在预先注射了非特异性 P2 受体拮抗剂苏拉明的小鼠中，LPS 处理小鼠腹膜中的 β 水平可以显着消除。因此，我们应该在寻找理想的抗炎候选药物时探索 P2 受体拮抗剂。