Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Philosophenweg 14, D-07743 Jena, Germany; Michael Popp Research Institute, University of Innsbruck, Mitterweg 24, 6120, Innsbruck, Austria.
Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, Philosophenweg 14, D-07743 Jena, Germany.
Biochem Pharmacol. 2020 May;175:113858. doi: 10.1016/j.bcp.2020.113858. Epub 2020 Feb 14.
Monocytes are professional immune cells that produce abundant levels of pro-inflammatory eicosanoids including prostaglandins and leukotrienes during inflammation. Vacuolar (H)-ATPase (V-ATPase) is critically involved in a variety of inflammatory processes including cytokine trafficking and lipid mediator biosynthesis. However, its role in eicosanoid biosynthetic pathways in monocytes remains elusive. Here, we present a differential role of V-ATPase in the expression and in the activity of cyclooxygenase (COX)-2 in human monocytes. Pharmacological targeting of V-ATPase increased the expression of COX-2 protein in lipopolysaccharide-stimulated primary monocytes, which was paralleled by enhanced phosphorylation of p38 MAPK and ERK-1/2, without impacting the NF-κB and SAPK/JNK pathways. Targeting of both p38 MAPK and ERK-1/2 pathways showed that the kinase pathways are crucial for COX-2 expression in human monocytes. Despite increased COX-2 protein levels, however, suppression of V-ATPase activity impaired the biosynthesis of COX- and also of 5-lipoxygenase (LOX)-derived lipid mediators in monocytes without affecting 12-/15-LOX products, assessed by a metabololipidomics approach using UPLC-MS-MS analysis. Our results indicate that changes in the intracellular pH may contribute to suppression of COX-2 and 5-LOX activities. We suggest that V-ATPase on one hand limits COX-2 protein levels via restricting p38 MAPK and ERK-1/2 activation, while on the other hand it governs the cellular activity of COX-2 through appropriate adjustment of the intracellular pH.
单核细胞是专业的免疫细胞，在炎症过程中会产生大量的促炎类二十烷酸，包括前列腺素和白三烯。液泡（H）-ATP 酶（V-ATPase）在多种炎症过程中起着关键作用，包括细胞因子运输和脂质介质的生物合成。然而，它在单核细胞中类二十烷酸生物合成途径中的作用仍不清楚。在这里，我们展示了 V-ATPase 在人单核细胞中环氧化酶（COX）-2 的表达和活性中的差异作用。V-ATPase 的药理学靶向增加了脂多糖刺激的原代单核细胞中 COX-2 蛋白的表达，这与 p38 MAPK 和 ERK-1/2 的磷酸化增强平行，而不影响 NF-κB 和 SAPK/JNK 途径。靶向 p38 MAPK 和 ERK-1/2 途径表明，激酶途径对于人单核细胞中 COX-2 的表达至关重要。然而，尽管 COX-2 蛋白水平升高，但 V-ATPase 活性的抑制会损害 COX 和 5-脂氧合酶（LOX）衍生的脂质介质在单核细胞中的生物合成，而不会影响 12-/15-LOX 产物，这是通过使用 UPLC-MS-MS 分析的代谢脂质组学方法评估的。我们的结果表明，细胞内 pH 的变化可能有助于抑制 COX-2 和 5-LOX 的活性。我们认为，V-ATPase 一方面通过限制 p38 MAPK 和 ERK-1/2 的激活来限制 COX-2 蛋白水平，另一方面通过适当调整细胞内 pH 来控制 COX-2 的细胞活性。
