Oxidized low-density lipoprotein (ox-LDL)-induced endothelial dysfunction plays an important role in the initiation and development of cardiovascular diseases, especially atherosclerosis (AS). Protease-activated receptor 2 (PAR-2) is a receptor for inflammatory proteases. However, the biological function of PAR-2 in endothelial cells and the pathophysiological process of AS are still unknown. In the current study, we found that treatment with ox-LDL increased the gene and protein expressions of PAR-2 in EA.hy926 endothelial cells. Interestingly, we found that antagonism of PAR-2 with its specific antagonist AZ3451 could ameliorate ox-LDL-induced lactate dehydrogenase (LDH) release. Treatment with AZ3451 considerably improved the mitochondrial function by restoring the mitochondrial membrane potential and increasing the levels of intracellular adenosine triphosphate (ATP). Also, we found that AZ3451 attenuated ox-LDL-induced expression and production of pro-inflammatory cytokines such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8). Treatment with AZ3451 also mitigated the expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Notably, our results demonstrated that the presence of AZ3451 alleviated ox-LDL-induced expression of the endothelial cell adhesion molecules vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1). Mechanistically, we found that AZ3451 attenuated ox-LDL-induced activation of nuclear factor-κB (NF-κB) by reducing the levels of intracellular NF-κB p65 and the luciferase activity of NF-κB promoter. Based on these findings, we conclude that PAR-2 might become a novel therapeutic target for the treatment of AS.

中文翻译：

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蛋白酶激活受体 2 (PAR-2) 拮抗剂 AZ3451 减轻氧化低密度脂蛋白 (Ox-LDL) 诱导的损伤和内皮炎症

氧化低密度脂蛋白（ox-LDL）诱导的内皮功能障碍在心血管疾病，特别是动脉粥样硬化（AS）的发生和发展中起重要作用。蛋白酶激活受体 2 (PAR-2) 是炎症蛋白酶的受体。然而，PAR-2在内皮细胞中的生物学功能和AS的病理生理过程仍不清楚。在目前的研究中，我们发现用ox-LDL处理增加了EA.hy926内皮细胞中PAR-2的基因和蛋白表达。有趣的是，我们发现 PAR-2 与其特异性拮抗剂 AZ3451 的拮抗作用可以改善 ox-LDL 诱导的乳酸脱氢酶 (LDH) 释放。AZ3451 治疗通过恢复线粒体膜电位和增加细胞内三磷酸腺苷 (ATP) 水平显着改善了线粒体功能。此外，我们发现 AZ3451 减弱了 ox-LDL 诱导的促炎细胞因子的表达和产生，例如白细胞介素 6 (IL-6)、肿瘤坏死因子-α (TNF-α) 和白细胞介素 8 (IL-8) ）。用 AZ3451 处理还减轻了基质金属蛋白酶 2 (MMP-2) 和基质金属蛋白酶 9 (MMP-9) 的表达。值得注意的是，我们的结果表明，AZ3451 的存在减轻了 ox-LDL 诱导的内皮细胞粘附分子血管细胞粘附分子-1 (VCAM-1) 和细胞间细胞粘附分子-1 (ICAM-1) 的表达。机械地，我们发现 AZ3451 通过降低细胞内 NF-κB p65 的水平和 NF-κB 启动子的荧光素酶活性来减弱 ox-LDL 诱导的核因子-κB (NF-κB) 的激活。基于这些发现，我们得出结论，PAR-2 可能成为治疗 AS 的新治疗靶点。