It is widely accepted that unesterified polyunsaturated ω-6 and ω-3 fatty acids (PUFA) are converted through various lipoxygenases, cyclooxygenases, and cytochrome P450 enzymes to a range of oxygenated derivatives (oxylipins), among which the polyhydroxides of unesterified PUFA have recently been recognized as cell signaling molecules with anti-inflammatory and pro-resolving properties, known as specialized pro-resolving mediators (SPMs). This study investigates the mono-, di-, and trihydroxy 16:0/PUFA-GPCs, and the corresponding 16:0/SPM-GPC, in plasma lipoproteins. We describe the isolation and identification of mono-, di-, and trihydroxy AA, EPA, and DHA-GPC in plasma LDL, HDL, HDL3, and acute phase HDL using normal phase LC/ESI-MS, as previously reported. The lipoproteins contained variable amounts of the polyhydroxy-PUFA-GPC (0–10 nmol/mg protein), likely the product of lipid peroxidation and the action of various lipoxygenases and cytochrome P450 enzymes on both free fatty acids and the parent GPCs. Polyhydroxy-PUFA-GPC was hydrolyzed to variable extent (20%–80%) by the different secretory phospholipases A₂ (sPLA₂s), with Group IIA sPLA₂ showing the lowest and Group X sPLA₂ the highest activity. Surprisingly, the trihydroxy-16:0/PUFA-GPC of APHDL was largely absent, while large amounts of unidentified material had migrated in the free fatty acid elution area. The free fatty acid mass spectra were consistent with that anticipated for branched chain polyhydroxy fatty acids. There was general agreement between the masses determined by LC/ESI-MS for the polyhydroxy PUFA-GPC and the masses calculated for the GPC equivalents of resolvins, protectins, and maresins using the fatty acid structures reported in the literature.

中文翻译：

---

IIA、V 和 X 分泌磷脂酶 A2 对多羟基多不饱和脂肪酸甘油磷酸胆碱的水解

人们普遍认为，未酯化的多不饱和 ω-6 和 ω-3 脂肪酸 (PUFA) 通过各种脂氧合酶、环氧合酶和细胞色素 P450 酶转化为一系列含氧衍生物 (oxylipins)，其中未酯化 PUFA 的多羟基化合物最近被认为是具有抗炎和促分解特性的细胞信号分子，被称为专门的促分解介质 (SPM)。本研究调查了血浆脂蛋白中的单羟基、双羟基和三羟基 16:0/PUFA-GPC，以及相应的 16:0/SPM-GPC。我们描述了使用正相 LC/ESI-MS 分离和鉴定血浆 LDL、HDL、HDL3 和急性期 HDL 中的单羟基、双羟基和三羟基 AA、EPA 和 DHA-GPC，如前所述。脂蛋白含有不同数量的多羟基-PUFA-GPC（0-10 nmol/mg 蛋白质），可能是脂质过氧化作用以及各种脂氧合酶和细胞色素 P450 酶对游离脂肪酸和母体 GPC 的作用的产物。多羟基-PUFA-GPC 被不同的分泌性磷脂酶 A 水解到不同程度 (20%–80%)₂ (sPLA ₂ s)，IIA sPLA ₂组活性最低，X sPLA ₂组活性最高。令人惊讶的是，APHDL 的 trihydroxy-16:0/PUFA-GPC 基本上不存在，而大量不明物质迁移到游离脂肪酸洗脱区域。游离脂肪酸质谱与支链多羟基脂肪酸的预期一致。通过 LC/ESI-MS 确定的多羟基 PUFA-GPC 的质量与使用文献中报道的脂肪酸结构为 GPC 等价物的 resolvins、protectins 和 maresins 计算的质量之间存在普遍的一致性。