Division of Cardiac Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China; The key Laboratory of Assisted Circulation, Ministry of Health, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China; National and Guangdong Province Joint Engineering Laboratory for Diagnosis and Treatment of Vascular Diseases, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China.
Division of Hypertension and Vascular Diseases, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China; The key Laboratory of Assisted Circulation, Ministry of Health, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China; National and Guangdong Province Joint Engineering Laboratory for Diagnosis and Treatment of Vascular Diseases, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510080, PR China.
J Mol Cell Cardiol. 2017 Nov;112:40-48. doi: 10.1016/j.yjmcc.2017.08.016. Epub 2017 Sep 1.
Endothelial dysfunction is an early stage of atherosclerosis. We recently have shown that 25-hydroxycholesterol found in atherosclerotic lesions could impair endothelial function and vasodilation by uncoupling and inhibiting endothelial nitric oxide synthase (eNOS). 1-Palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC), the oxidation product of oxidized low-density lipoprotein, is another proinflammatory lipid and has also been found in atherosclerotic lesions. However, whether POVPC promotes atherosclerosis like 25-hydroxycholesterol remains unclear. The purpose of this study was to explore the effects of POVPC on endothelial function and vasodilation. Human umbilical vein endothelial cells (HUVECs) were incubated with POVPC. Endothelial cell proliferation, migration and tube formation were measured. Nitric oxide (NO) production and superoxide anion generation (O) were determined. The expression and phosphorylation of endothelial nitric oxide synthase (eNOS), AKT, PKC-βII and P70S6K as well as the association of eNOS and heat shock protein 90 (HSP90) were detected by immunoblotting and immunoprecipitation. Endothelial cell apoptosis was monitored by TUNEL staining. The expression of Bcl-2, Bax, and Cleaved Caspase 3 were detected by immunoblotting. Finally, aortic ring from C57BL6 mice were isolated and treated with POVPC and the endothelium-dependent vasodilation was evaluated. POVPC significantly inhibited HUVECs proliferation, migration, tube formation, decreased NO production but increased O generation. POVPC inhibited the phosphorylation of Akt and eNOS at Ser1177, increased activation of PKC-βII, P70S6K and the phosphorylation of eNOS at Thr495, reduced the association of HSP90 with eNOS. Meanwhile, POVPC induced endothelial cell apoptosis by inhibiting Bcl-2 expression, increasing Bax and cleaved caspase-3 expressions as well as caspase-3 activity and impaired endothelium-dependent vasodilation. These data demonstrated that POVPC impaired endothelial function by uncoupling and inhibiting eNOS as well as by inducing endothelial cell apoptosis. Therefore, POVPC may play an important role in the development of atherosclerosis and may be considered as a potential therapeutic target for atherosclerosis.
内皮功能障碍是动脉粥样硬化的早期阶段。我们最近的研究表明，在动脉粥样硬化病变中发现的 25-羟胆固醇可能通过解偶联和抑制内皮型一氧化氮合酶（eNOS）来损害内皮功能和血管舒张。1-棕榈酰基-2-（5-氧代戊酰基）-sn-甘油-3-磷酸胆碱（POVPC）是氧化型低密度脂蛋白的氧化产物，是另一种促炎脂质，也存在于动脉粥样硬化病变中。然而，POVPC 是否像 25-羟胆固醇一样促进动脉粥样硬化尚不清楚。本研究旨在探讨 POVPC 对内皮功能和血管舒张的影响。用人脐静脉内皮细胞（HUVEC）孵育 POVPC。测量内皮细胞增殖、迁移和管形成。测定一氧化氮（NO）生成和超氧阴离子生成（O）。通过免疫印迹和免疫沉淀检测内皮型一氧化氮合酶（eNOS）、AKT、PKC-βII 和 P70S6K 的表达和磷酸化以及 eNOS 与热休克蛋白 90（HSP90）的结合。通过 TUNEL 染色监测内皮细胞凋亡。通过免疫印迹检测 Bcl-2、Bax 和 Cleaved Caspase 3 的表达。最后，分离 C57BL6 小鼠的主动脉环，并用 POVPC 处理，并评估内皮依赖性血管舒张。POVPC 显著抑制 HUVEC 增殖、迁移、管形成，减少 NO 生成，但增加 O 生成。POVPC 抑制 Akt 和 eNOS 在 Ser1177 的磷酸化，增加 PKC-βII、P70S6K 的激活和 eNOS 在 Thr495 的磷酸化，减少 HSP90 与 eNOS 的结合。同时，POVPC 通过抑制 Bcl-2 表达、增加 Bax 和 cleaved caspase-3 表达以及 caspase-3 活性，诱导内皮细胞凋亡，从而损害内皮依赖性血管舒张。这些数据表明，POVPC 通过解偶联和抑制 eNOS 以及诱导内皮细胞凋亡来损害内皮功能。因此，POVPC 可能在动脉粥样硬化的发展中起重要作用，并可作为动脉粥样硬化的潜在治疗靶点。
