Patricia M K, Kim J A, Harper C M, Shih P T, Berliner J A, Natarajan R, Nadler J L, Hedrick C C
Division of Cardiology, University of California at Los Angeles, 90095-1679, USA.
Arterioscler Thromb Vasc Biol. 1999 Nov;19(11):2615-22. doi: 10.1161/01.atv.19.11.2615.
The development of atherosclerosis is accelerated in individuals with type 2 diabetes. Adhesion of monocytes to the vascular endothelium is a key initial step in atherogenesis. We have previously shown that monocyte adhesion to human aortic endothelial cells (HAECs) cultured long-term in high-glucose medium (25 mmol/L, 2 passages) is increased compared with cells grown in normal glucose (5 mmol/L). One potential mechanism for increased monocyte adhesion to HAECs under hyperglycemic conditions is via the 12-lipoxygenase (12-LO) pathway. In this study, we demonstrated in HAECs that the major LO metabolite of arachidonic acid was the 12-LO product, 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE], which was increased severalfold in HAECs cultured under high-glucose conditions. Furthermore, treatment of HAECs with 12(S)-HETE induced monocyte, but not neutrophil, adhesion an average of 3-fold (range of 1.5- to 5-fold) compared with untreated cells (75+/-5 versus 26+/-1 monocytes per field, respectively, P<0.001). Expression of the adhesion molecules vascular cell adhesion molecule-1, E-selectin, and intercellular adhesion molecule-1 was not significantly increased. However, both glucose and 12(S)-HETE induced a 60% increase in HAEC surface expression of connecting segment-1 (ie, CS-1) fibronectin, a ligand for very late-acting antigen-4 (VLA-4). The antibodies used to block monocyte integrin VLA-4 and leukocyte function-related antigen-1, a monocytic counterreceptor for intercellular adhesion molecule-1, inhibited the ability of both 12-LO products and high glucose to induce monocyte adhesion. These results definitively demonstrate for the first time in HAECs that the 12-LO pathway can induce monocyte-endothelial cell interaction and that the effects of glucose may be mediated, at least in part, through this pathway. Thus, these results suggest that the 12-LO pathway may play a role in the increased susceptibility of diabetics to atherosclerosis.
2型糖尿病患者动脉粥样硬化的发展会加速。单核细胞与血管内皮的黏附是动脉粥样硬化形成的关键起始步骤。我们之前已经表明,与在正常葡萄糖(5 mmol/L)中生长的细胞相比,在高糖培养基(25 mmol/L,传代2次)中长期培养的人主动脉内皮细胞(HAECs)对单核细胞的黏附增加。高血糖条件下单核细胞与HAECs黏附增加的一种潜在机制是通过12-脂氧合酶(12-LO)途径。在本研究中,我们在HAECs中证明,花生四烯酸的主要脂氧合酶代谢产物是12-LO产物12(S)-羟基二十碳四烯酸[12(S)-HETE],在高糖条件下培养的HAECs中其增加了数倍。此外,用12(S)-HETE处理HAECs可诱导单核细胞而非中性粒细胞的黏附,与未处理细胞相比平均增加3倍(范围为1.5至5倍)(每视野分别为75±5个与26±1个单核细胞,P<0.001)。黏附分子血管细胞黏附分子-1、E-选择素和细胞间黏附分子-1的表达没有显著增加。然而,葡萄糖和12(S)-HETE均使HAECs表面连接段-1(即CS-1)纤连蛋白的表达增加60%,CS-1纤连蛋白是极晚期抗原-4(VLA-4)的配体。用于阻断单核细胞整合素VLA-4和白细胞功能相关抗原-1(细胞间黏附分子-1的单核细胞反受体)的抗体,抑制了12-LO产物和高糖诱导单核细胞黏附的能力。这些结果首次在HAECs中明确证明12-LO途径可诱导单核细胞-内皮细胞相互作用,并且葡萄糖的作用可能至少部分通过该途径介导。因此,这些结果表明12-LO途径可能在糖尿病患者动脉粥样硬化易感性增加中起作用。