Jokesch Philipp, Oskolkova Olga, Fedorova Maria, Gesslbauer Bernd, Bochkov Valery
Institute of Pharmaceutical Sciences, Department of Pharmaceutical Chemistry, University of Graz, Graz, Austria.
Center of Membrane Biochemistry and Lipid Research, University Hospital Carl Gustav Carus and Faculty of Medicine of TU Dresden, Dresden, Germany.
J Lipid Res. 2025 Feb;66(2):100742. doi: 10.1016/j.jlr.2025.100742. Epub 2025 Jan 6.
Phospholipids containing oxidized esterified PUFA residues (OxPLs) are increasingly recognized for multiple biological activities and causative involvement in disease pathogenesis. Pharmacokinetics of these compounds in blood plasma is essentially not studied. Human plasma contains both genuine phospholipases A [platelet activating factor acetyl hydrolase (PAF-AH) (also called Lp-PLA) and secretory phospholipase A2] and multifunctional enzymes capable of removing sn-2 residues in native and oxidized PLs (lecithin-cholesterol acyltransferase, peroxiredoxin-6). The goal of this study was to compare relative activities of different PLA enzymes by analyzing cleavage of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylcholine (OxPAPC) and oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylethanolamine (OxPAPE) by diluted plasma in the presence of enzyme inhibitors. We have found that human plasma demonstrated high total PLA activity against oxidized PCs and PEs. PAF-AH/Lp-PLA played a dominant role in LysoPC and LysoPE production as compared to other enzymes. Molecular species of oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylcholine and oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphatidylethanolamine could be divided into three groups according to their degradation rate and sensitivity to PAF-AH/Lp-PLA inhibitor darapladib. Oxidatively truncated species were most rapidly metabolized in the presence of plasma; this process was strongly inhibited by darapladib. The rate of degradation of full-length OxPLs depended on the degree of oxygenation. Species containing 1 to 3 oxygen atoms were relatively stable to degradation in plasma, while OxPLs containing > 3 extra oxygens were degraded but at significantly slower rate than truncated species. In contrast to truncated species, degradation of full-length OxPLs with > 3 extra oxygens were only minimally inhibited by darapladib. These data provide further insights into the mechanisms regulating circulating levels of OxPLs and lipid mediators generated by PLA cleavage of OxPLs, namely oxylipins and LysoPC.
含有氧化酯化多不饱和脂肪酸残基的磷脂（氧化磷脂，OxPLs）因其多种生物学活性以及在疾病发病机制中的因果关系而日益受到关注。这些化合物在血浆中的药代动力学基本上尚未得到研究。人血浆中既含有真正的磷脂酶A[血小板活化因子乙酰水解酶（PAF-AH）（也称为Lp-PLA）和分泌型磷脂酶A2]，也含有能够去除天然和氧化磷脂中sn-2残基的多功能酶（卵磷脂胆固醇酰基转移酶、过氧化物酶体增殖物激活受体6）。本研究的目的是通过分析在酶抑制剂存在下稀释血浆对氧化的1-棕榈酰-2-花生四烯酰-sn-甘油-磷脂酰胆碱（OxPAPC）和氧化的1-棕榈酰-2-花生四烯酰-sn-甘油-磷脂酰乙醇胺（OxPAPE）的裂解情况，比较不同磷脂酶A的相对活性。我们发现，人血浆对氧化的磷脂酰胆碱和磷脂酰乙醇胺表现出较高的总磷脂酶A活性。与其他酶相比，PAF-AH/Lp-PLA在溶血磷脂酰胆碱和溶血磷脂酰乙醇胺的产生中起主导作用。氧化的1-棕榈酰-2-花生四烯酰-sn-甘油-磷脂酰胆碱和氧化的1-棕榈酰-2-花生四烯酰-sn-甘油-磷脂酰乙醇胺的分子种类可根据其降解速率和对PAF-AH/Lp-PLA抑制剂达普拉地布的敏感性分为三组。氧化截短的种类在血浆存在下代谢最快；这一过程受到达普拉地布的强烈抑制。全长氧化磷脂的降解速率取决于氧化程度。含有1至3个氧原子的种类在血浆中对降解相对稳定，而含有>3个额外氧原子的氧化磷脂会降解，但速率明显慢于截短的种类。与截短的种类相反，含有>3个额外氧原子的全长氧化磷脂的降解仅受到达普拉地布的轻微抑制。这些数据为调节氧化磷脂循环水平以及由氧化磷脂的磷脂酶A裂解产生的脂质介质（即氧化脂质和溶血磷脂酰胆碱）的机制提供了进一步的见解。
