Department of Bioregulation, Nippon Medical School, Kawasaki, Kanagawa, Japan.
Atherosclerosis. 2013 Feb;226(2):373-7. doi: 10.1016/j.atherosclerosis.2012.12.012. Epub 2012 Dec 25.
Adiponectin (APN) is an adipocytokine with anti-atherogenic and anti-inflammatory properties. Hypoadiponectinemia may associate with increased risk for coronary artery disease (CAD) and acute coronary syndrome (ACS). Tissue factor (TF) initiates thrombus formation and facilitates luminal occlusion after plaque rupture, a common cause of fatal ACS. This study tested the hypothesis that APN influences TF expression by macrophages (MΦ), inflammatory cells found in atheromatous plaques.
Human monocyte-derived MΦ or RAW 264.7 cells transfected with TF promoter construct, pretreated with a physiological range of recombinant APN (1-10 μg/ml), received LPS stimulation. TF mRNA and protein levels were quantified by real-time RT-PCR and ELISA. TF pro-coagulant activity was evaluated by one-step clotting assay. TF promoter activity was determined by a dual-luciferase reporter assay. Immunoblot analyses assessed intracellular signaling pathways.
APN treatment suppressed TF mRNA expression and protein production in LPS-stimulated human MΦ, compared to vehicle controls. APN treatment also significantly reduced TF pro-coagulant activity in lysates of LPS-stimulated human MΦ, compared to vehicle controls. Moreover, APN suppressed TF promoter activity in LPS-stimulated MΦ compared to controls. APN suppressed phosphorylation and degradation of IκB-α in LPS-stimulated MΦ.
APN reduces thrombogenic potential of MΦ by inhibiting TF expression and activity. These observations provide a potential mechanistic link between low APN levels and the thrombotic complications of atherosclerosis.
脂联素（APN）是一种具有抗动脉粥样硬化和抗炎特性的脂肪细胞因子。低脂联素血症可能与冠心病（CAD）和急性冠脉综合征（ACS）的风险增加有关。组织因子（TF）启动血栓形成，并在斑块破裂后促进管腔闭塞，这是致命性 ACS 的常见原因。本研究通过检测 APN 是否影响动脉粥样斑块中炎症细胞巨噬细胞（MΦ）的 TF 表达来验证假说。
用生理范围内的重组 APN（1-10μg/ml）预处理单核细胞来源的 MΦ或 RAW 264.7 细胞转染 TF 启动子构建体，然后接受 LPS 刺激。通过实时 RT-PCR 和 ELISA 定量检测 TF mRNA 和蛋白水平。通过一步法凝血测定评估 TF 促凝活性。通过双荧光素酶报告基因测定确定 TF 启动子活性。免疫印迹分析评估细胞内信号通路。
与载体对照组相比，APN 处理可抑制 LPS 刺激的人 MΦ中的 TF mRNA 表达和蛋白产生。与载体对照组相比，APN 处理还显著降低了 LPS 刺激的人 MΦ裂解物中的 TF 促凝活性。此外，与对照组相比，APN 抑制了 LPS 刺激的 MΦ中的 TF 启动子活性。APN 抑制了 LPS 刺激的 MΦ中 IκB-α 的磷酸化和降解。
APN 通过抑制 TF 表达和活性降低了 MΦ的血栓形成潜力。这些观察结果为低 APN 水平与动脉粥样硬化的血栓并发症之间的潜在机制联系提供了依据。
