Wildsmith Kristin R, Albert Carolyn J, Anbukumar Dhanalakshmi S, Ford David A
Department of Biochemistry and Molecular Biology, St. Louis University Health Sciences Center, St. Louis, Missouri 63104.
Department of Biochemistry and Molecular Biology, St. Louis University Health Sciences Center, St. Louis, Missouri 63104.
J Biol Chem. 2006 Jun 23;281(25):16849-16860. doi: 10.1074/jbc.M602505200. Epub 2006 Apr 11.
Numerous studies have suggested relationships between myeloperoxidase (MPO), inflammation, and atherosclerosis. MPO-derived reactive chlorinating species attack membrane plasmalogens releasing alpha-chloro fatty aldehydes including 2-chlorohexadecanal (2-ClHDA), which have been found to accumulate in activated neutrophils, activated monocytes, infarcted myocardium and human atheromas. The present study employed synthetically prepared 2-Cl-[3H]-HDA as well as stable isotope-labeled 2-ClHDA to elucidate the metabolism of 2-ClHDA. The results herein demonstrate that human coronary artery endothelial cells oxidize and reduce 2-ClHDA to its respective chlorinated fatty acid (alpha-ClFA) and chlorinated fatty alcohol (alpha-ClFOH). Within the first hour of incubations of human coronary artery endothelial cells with 2-Cl-[3H]-HDA, the label was incorporated into the alpha-ClFOH and alpha-ClFA pools. After 1 h, the radiolabel was predominantly found in the alpha-ClFOH pool. Cell-derived alpha-ClFOH and alpha-ClFA were also released into the cell culture medium. Additionally, chlorinated fatty acid was incorporated into complex endothelial cell glycerolipids, including monoglycerides, triglycerides, phosphatidylcholine, and phosphatidylethanolamine. The oxidation and reduction of 2-ClHDA to alpha-ClFA and alpha-ClFOH, respectively, was further supported by mass spectrometric analyses of human coronary artery endothelial cells incubated with either 2-ClHDA or stable isotope-labeled 2-ClHDA (2-Cl-[d4]-HDA). 2-ClHDA was also oxidized to alpha-ClFA and reduced to alpha-ClFOH in both control and phorbol 12-myristate 13-acetate-stimulated neutrophils. Taken together, these results show that a family of chlorinated lipidic metabolites is produced from alpha-chloro fatty aldehydes derived from reactive chlorinating species targeting of plasmalogens. These metabolites are incorporated into complex lipids and their biological roles may provide new insights into MPO-mediated disease.
众多研究表明髓过氧化物酶（MPO）、炎症与动脉粥样硬化之间存在关联。MPO衍生的活性氯化物质攻击膜缩醛磷脂，释放出α-氯代脂肪醛，包括2-氯十六醛（2-ClHDA），已发现其在活化的中性粒细胞、活化的单核细胞、梗死心肌和人类动脉粥样硬化斑块中积累。本研究采用合成制备的2-Cl-[3H]-HDA以及稳定同位素标记的2-ClHDA来阐明2-ClHDA的代谢。本文结果表明，人冠状动脉内皮细胞将2-ClHDA氧化并还原为其相应的氯代脂肪酸（α-ClFA）和氯代脂肪醇（α-ClFOH）。在用2-Cl-[3H]-HDA孵育人冠状动脉内皮细胞的第一小时内，标记物被掺入α-ClFOH和α-ClFA库中。1小时后，放射性标记主要存在于α-ClFOH库中。细胞衍生的α-ClFOH和α-ClFA也被释放到细胞培养基中。此外，氯代脂肪酸被掺入复杂的内皮细胞甘油脂质中，包括单甘油酯、甘油三酯、磷脂酰胆碱和磷脂酰乙醇胺。对用2-ClHDA或稳定同位素标记的2-ClHDA（2-Cl-[d4]-HDA）孵育的人冠状动脉内皮细胞进行质谱分析，进一步支持了2-ClHDA分别氧化为α-ClFA和还原为α-ClFOH的过程。在对照和佛波醇12-肉豆蔻酸酯13-乙酸酯刺激的中性粒细胞中，2-ClHDA也被氧化为α-ClFA并还原为α-ClFOH。综上所述，这些结果表明，一类氯代脂质代谢产物是由针对缩醛磷脂的活性氯化物质衍生的α-氯代脂肪醛产生的。这些代谢产物被掺入复杂脂质中，它们的生物学作用可能为MPO介导的疾病提供新的见解。
