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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。
Phosphatidylcholine hydroperoxide (PCOOH) is the initial product of phosphatidylcholine (PC) oxidation and can be detected in plasma and tissue under various pathological conditions including atherosclerosis To To assess the degree of atherosclerosis, we investigated the effect of PCOOH on the adhesion of THP-1 cells to intracellular adhesion molecule-1 (ICAM-1) and found that THP-1 cells adhere to endothelial cells Molecular adhesion is dose dependent on PCOOH. Non-oxidized PC, sn-2 truncated PC, and other peroxides did not affect the adhesion of THP-1 cells to endothelial cell adhesion molecules. In PCOOH-treated cells, a prominent F-actin-rich membrane structure was found on which antigen (lymphocyte function-associated antigen-1, LFA-1) associated with lymphocyte function was located. Cytochalasin D and actin polymerization inhibitors can inhibit PCOOH-induced cell adhesion to ICAM-1 and membrane protrusions. We studied the Rho-family GTPases involved in PCOOH-induced THP-1 cell adhesion to ICAM-1 and found that the depletion of isoprene by fluvastatin and the blockade of GGTI-286 on bovine-derived transferase were all inhibited PCOOH induced cell adhesion to ICAM-1 and membrane. The Pull-down method shows that Rac1 and Rac2 are activated in PCOOH-treated cells. Pan-Rho-family GTPase inhibitors RNAi interference of Clostridium difficile B, Rac specific inhibitors NSC23776 and Rac isoforms reduced cell adhesion. These results indicate that PCOOH-induced LFA-1-regulated cell adhesion to ICAM-1 is through the actin cytoskeleton. This mechanism may be involved in monocyte adhesion to the arterial wall and initiating atherosclerosis.