磷脂酰胆碱过氧化物的测量和生化机理及其在动脉粥样硬化中的应用(英文)

磷脂酰胆碱过氧化物(phosphatidylcholine hydroperoxide,PCOOH)是磷脂酰胆碱(phosphatidylcholine,PC)氧化的最初产物,在包括动脉粥样硬化在内的各种病理条件下,可以在血浆和组织中检测到。为了评定动脉粥样硬化的程度,我们研究了PCOOH对THP-1细胞与内皮细胞黏附分子(intracellular adhesionmolecule-1,ICAM-1)之间粘附状态的影响,发现THP-1细胞与内皮细胞黏附分子的粘附是剂量依赖于PCOOH的。不氧化的PC、sn-2截断的PC和其他过氧化物不影响THP-1细胞与内皮细胞黏附分子的黏附。在PCOOH处理的细胞中,发现了F-肌动蛋白富集的突出膜结构,与淋巴细胞功能关联的抗原(lymphocytefunction-associated antigen-1,LFA-1)定位在突出结构上。细胞松弛素D和肌动蛋白聚合抑制剂能够抑制PCOOH诱导细胞黏附到ICAM-1和膜突起上。我们研究了参与PCOOH诱导THP-1细胞黏附到ICAM-1上的Rho-家族的GTP酶,发现氟伐他汀对异戊二烯的消耗以及GGTI-286对牛儿基转移酶的阻害均能够抑制PCOOH诱导细胞黏附到ICAM-1和膜上。Pull-down方法表明,在PCOOH处理的细胞中,Rac1和Rac2被活化。Pan-Rho-家族的GTP酶抑制剂难辨梭状芽孢杆菌B、Rac特异抑制剂NSC23776和Rac同型体的RNA干扰,均能够减少细胞黏附。这些结果表明,PCOOH诱导的LFA-1调节的细胞黏附到ICAM-1上是通过actin细胞骨架。这一机理可能参与了单核细胞黏附到动脉壁上并启动了动脉粥样硬化。

Biochemistry and Measurement of Phosphatidylcholine Hydroperoxide:Implications for Atherosclerosis

The accumulation of phosphatidylcholine hydroperoxide(PCOOH),a primary oxidation product of phosphatidylcholine(PC),in blood plasma and tissues has been observed in various pathological conditions,including atherosclerosis.To estimate the atherogenicity,the effect of PCOOH on THP-1 monocytic cell adherence to immobilized vascular endothelial cell adhesion molecules were evaluated.THP-1 cell adhesion to intracellular adhesion molecule-1(ICAM-1) was dose dependently increased by addition of PCOOH.Unoxidized PC,sn-2 truncated PCs,and other hydroperoxide compounds did not affect the adhesion.In the PCOOH-treated cells,obvious protruding F-actin-rich membrane structures were formed,and lymphocyte function-associated antigen-1(LFA-1) was localized to the protruding structures.Cytochalasin D,an actin polymerization inhibitor,suppressed the PCOOH-induced cell adhesion to ICAM-1 and the membrane protrusions.Next the involvement of Rho-family GTPases in PCOOH-induced THP-1 cell adhesion to ICAM-1 was investigated.Isoprenoid depletion by fluvastatin and geranylgeranyltransferase inhibition by GGTI-286 suppressed PCOOH-induced cell adhesion to ICAM-1 and F-actin-rich membrane protrusion formation.Pull-down assays demonstrated the activation of Rac1 and Rac2 in PCOOH-treated cells.Pan-Rho-family GTPase inhibitor Clostridium difficile toxin B,Rac-specific inhibitor NSC23776,and RNA interference of the Rac isoforms suppressed the cell adhesion.These findings indicate the involvement of Rac GTPase activation in PCOOH-induced cell adhesion to ICAM-1 via actin reorganization.These results indicate that PCOOH evokes LFA-1-mediated cell adhesion to ICAM-1 via actin cytoskeletal organization,and the mechanism may participate in monocyte adherence to the arterial wall in the initiation of atherosclerosis.