Laboratory for Experimental Orthopaedics, Department of Orthopaedics, Justus Liebig University Giessen, 35392 Giessen, Germany.
Department of Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, 93053 Regensburg, Germany.
Int J Mol Sci. 2019 Jan 15;20(2):342. doi: 10.3390/ijms20020342.
Phospholipids (PLs) possess the unique ability to contribute to synovial joint lubrication. The aim of our study was to determine for the first time the effect of dexamethasone and some adrenergic and cholinergic agonists on the biosynthesis and release of PLs from human fibroblast-like synoviocytes (FLS). Osteoarthritic human knee FLS were treated with dexamethasone, terbutaline, epinephrine, carbachol, and pilocarpine, or the glucocorticoid receptor antagonist RU 486. Simultaneously PL biosynthesis was determined through the incorporation of stable isotope-labeled precursors into PLs. Radioactive isotope-labeled precursors were used to radiolabel PLs for the subsequent quantification of their release into nutrient media. Lipids were extracted and quantified using electrospray ionization tandem mass spectrometry or liquid scintillation counting. Dexamethasone significantly decreased the biosynthesis of phosphatidylcholine, phosphatidylethanolamine (PE), PE-based plasmalogen, and sphingomyelin. The addition of RU 486 abolished these effects. A release of PLs from FLS into nutrient media was not recognized by any of the tested agents. None of the adrenergic or cholinergic receptor agonists modulated the PL biosynthesis. We demonstrate for the first time an inhibitory effect of dexamethasone on the PL biosynthesis of FLS from human knees. Moreover, our study indicates that the PL metabolism of synovial joints and lungs are differently regulated.
磷脂（PLs）具有促进滑液关节润滑的独特能力。我们的研究目的是首次确定地塞米松和一些肾上腺素能和胆碱能激动剂对人成纤维样滑膜细胞（FLS）中 PLs 的生物合成和释放的影响。用地塞米松、特布他林、肾上腺素、卡巴胆碱和毛果芸香碱或糖皮质激素受体拮抗剂 RU 486 处理骨关节炎患者的膝关节 FLS。同时，通过将稳定同位素标记的前体掺入 PLs 中来确定 PL 生物合成。放射性同位素标记的前体用于标记 PL，以便随后定量其释放到营养培养基中。使用电喷雾串联质谱或液体闪烁计数法提取和定量脂质。地塞米松显著降低了磷脂酰胆碱、磷脂酰乙醇胺（PE）、PE 基质体和神经鞘磷脂的生物合成。添加 RU 486 消除了这些影响。从 FLS 释放到营养培养基中的 PLs 没有被任何测试的药物识别。没有一种肾上腺素能或胆碱能受体激动剂调节 PL 生物合成。我们首次证明地塞米松对来自人膝关节的 FLS 中 PL 生物合成具有抑制作用。此外，我们的研究表明，滑液关节和肺部的 PL 代谢受到不同的调节。
