Subbanagounder Ganesamoorthy, Deng Yujin, Borromeo Christine, Dooley Alek N, Berliner Judith A, Salomon Robert G
Department of Medicine/Cardiology, Center for the Health Sciences, Room 47-123, UCLA Medical Center, Los Angeles, CA 90095-1679, USA.
Vascul Pharmacol. 2002 Apr;38(4):201-9. doi: 10.1016/s1537-1891(02)00170-2.
Monocyte recruitment into the vessel wall plays an important role in atherogenesis. Polar lipid components of minimally modified/oxidized LDL were shown to activate endothelial cells to increase the synthesis of monocyte chemotactic factors and surface expression of adhesion molecules. We previously reported regulation of endothelial cell inflammatory functions by oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (Ox-PAPC) and three component oxidized phospholipids, containing oxovaleroyl (POVPC), glutaroyl (PGPC) and epoxyisoprostane (PEIPC) groups at the sn-2 position of oxidized phospholipids. In the present study, we demonstrate the presence of gamma-hydroxy-alpha,beta-unsaturated aldehydic phospholipid, 1-palmitoyl-2-(5-hydroxy-8-oxooct-6-enoyl)-sn-glycero-3-phosphocholine (HOOA-PC; m/z 650.4), in Ox-PAPC by liquid chromatography/mass spectrometry (LC/MS), LC/MS/MS, derivatization and tandem mass spectrometric analyses. This was further unambiguously confirmed by the identical chromatographic and mass spectrometric characteristics of Ox-PAPC-derived m/z 650.4 with synthetic HOOA-PC. The time course of PAPC autoxidation showed that HOOA-PC accumulates with oxidation and represents about 2% of Ox-PAPC. We have also examined the effects of HOOA-PC on leukocyte-endothelial interactions. HOOA-PC dose-dependently activated human aortic endothelial cells (HAECs) to bind monocytes (twofold at 10 micrograms/ml) and caused a dose-dependent increase (two- to threefold) in levels of monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8)--chemokines that are important in monocyte entry into chronic lesions. HOOA-PC also inhibited LPS-induced expression of E-Selectin, a major adhesion molecule that mediates neutrophil endothelial interactions. The present study suggests that the HOOA-PC exerts its effects on endothelial cells as a free lipid. These studies demonstrate the importance of HOOA-PC as a new potential proinflammatory molecule that regulates leukocyte-endothelial interactions.
单核细胞募集到血管壁在动脉粥样硬化形成过程中起着重要作用。研究表明，轻度修饰/氧化的低密度脂蛋白（LDL）的极性脂质成分可激活内皮细胞，增加单核细胞趋化因子的合成以及黏附分子的表面表达。我们之前报道过氧化1-棕榈酰-2-花生四烯酰-sn-甘油-3-磷酸胆碱（Ox-PAPC）以及在氧化磷脂sn-2位含有氧代戊酰基（POVPC）、戊二酰基（PGPC）和环氧异前列腺素（PEIPC）基团的三种组分氧化磷脂对内皮细胞炎症功能的调节作用。在本研究中，我们通过液相色谱/质谱（LC/MS）、LC/MS/MS、衍生化和串联质谱分析，证实在Ox-PAPC中存在γ-羟基-α,β-不饱和醛磷脂，即1-棕榈酰-2-(5-羟基-8-氧代辛-6-烯酰)-sn-甘油-3-磷酸胆碱（HOOA-PC；m/z 650.4）。通过Ox-PAPC衍生的m/z 650.4与合成的HOOA-PC具有相同的色谱和质谱特征，进一步明确证实了这一点。PAPC自动氧化的时间进程表明，HOOA-PC随着氧化而积累，约占Ox-PAPC的2%。我们还研究了HOOA-PC对白细胞-内皮细胞相互作用的影响。HOOA-PC剂量依赖性地激活人主动脉内皮细胞（HAECs）以结合单核细胞（在10微克/毫升时增加两倍），并导致单核细胞趋化蛋白-1（MCP-1）和白细胞介素-8（IL-8）水平呈剂量依赖性增加（增加两到三倍），这两种趋化因子在单核细胞进入慢性病变中起重要作用。HOOA-PC还抑制脂多糖（LPS）诱导的E-选择素表达，E-选择素是介导中性粒细胞与内皮细胞相互作用的主要黏附分子。本研究表明，HOOA-PC作为一种游离脂质对内皮细胞发挥作用。这些研究证明了HOOA-PC作为一种调节白细胞-内皮细胞相互作用的新型潜在促炎分子的重要性。
