Abstract：
OBJECTIVE: Since diabetic patients with coronary microvascular dysfunction (CMD) exhibit high cardiac mortality and women have higher prevalence of non-obstructive coronary artery disease than men, we tried to expand the limited understanding about the etiology and the sex difference of diabetic CMD.
RESULTS: Accumulated methylglyoxal (MGO) due to diabetes promotes vascular damage and it was used for mimicking diabetic status. Flow cytometry analysis and isometric tension measurement were performed to evaluate coronary artery endothelial injury. MGO induced apoptosis of coronary endothelial cells, accompanied by downregulation of androgen receptor (AR). Lentivirus-mediated stable expression of AR in coronary endothelial cells increased anti-apoptotic Bcl-2 expression and attenuated MGO-induced cell apoptosis. cPLA2 activation was the downstream of AR downregulation by MGO treatment. Moreover, MGO also activated cPLA2 rapidly to impair endothelium-dependent vasodilation of coronary arteries from mice. Reactive oxygen species (ROS) overproduction was demonstrated to account for MGO-mediated cPLA2 activation and endothelial dysfunction. Importantly, AR blockade increased endothelial ROS production whereas AR activation protected coronary artery endothelial vasodilatory function from the MGO-induced injury. Although galectin-3 upregulation was confirmed by siRNA knockdown in endothelial cells not to participate in MGO-induced endothelial apoptosis, pharmacological inhibitor of galectin-3 further enhanced MGO-triggered ROS generation and coronary artery endothelial impairment.
CONCLUSIONS: Our data proposed the AR downregulation-ROS overproduction-cPLA2 activation pathway as one of the mechanisms underlying diabetic CMD and postulated a possible reason for the sex difference of CMD-related angina. Meanwhile, MGO-induced galectin-3 activation played a compensatory role against coronary endothelial dysfunction.
RESULTS: Accumulated methylglyoxal (MGO) due to diabetes promotes vascular damage and it was used for mimicking diabetic status. Flow cytometry analysis and isometric tension measurement were performed to evaluate coronary artery endothelial injury. MGO induced apoptosis of coronary endothelial cells, accompanied by downregulation of androgen receptor (AR). Lentivirus-mediated stable expression of AR in coronary endothelial cells increased anti-apoptotic Bcl-2 expression and attenuated MGO-induced cell apoptosis. cPLA2 activation was the downstream of AR downregulation by MGO treatment. Moreover, MGO also activated cPLA2 rapidly to impair endothelium-dependent vasodilation of coronary arteries from mice. Reactive oxygen species (ROS) overproduction was demonstrated to account for MGO-mediated cPLA2 activation and endothelial dysfunction. Importantly, AR blockade increased endothelial ROS production whereas AR activation protected coronary artery endothelial vasodilatory function from the MGO-induced injury. Although galectin-3 upregulation was confirmed by siRNA knockdown in endothelial cells not to participate in MGO-induced endothelial apoptosis, pharmacological inhibitor of galectin-3 further enhanced MGO-triggered ROS generation and coronary artery endothelial impairment.
CONCLUSIONS: Our data proposed the AR downregulation-ROS overproduction-cPLA2 activation pathway as one of the mechanisms underlying diabetic CMD and postulated a possible reason for the sex difference of CMD-related angina. Meanwhile, MGO-induced galectin-3 activation played a compensatory role against coronary endothelial dysfunction.
摘要：
目的：由于糖尿病患者冠状动脉微血管功能障碍（CMD）的心脏死亡率高，女性非阻塞性冠状动脉疾病的患病率高于男性，我们试图扩大对糖尿病CMD的病因和性别差异的有限认识。
结果：由于糖尿病引起的甲基乙二醛（MGO）积累促进血管损伤，并用于模仿糖尿病状态。采用流式细胞术分析和等距张力测量评价冠状动脉内皮损伤。MGO诱导冠状动脉内皮细胞凋亡,伴随雄激素受体（AR）的下调。慢病毒介导的AR在冠状动脉内皮细胞中的稳定表达增加了抗凋亡Bcl-2的表达并减弱了MGO诱导的细胞凋亡。cPLA2激活是MGO处理下调AR的下游。此外，MGO还快速激活cPLA2以损害来自小鼠的冠状动脉的内皮依赖性血管舒张。证明了活性氧（ROS）的过度产生是MGO介导的cPLA2活化和内皮功能障碍的原因。重要的是,AR阻断增加内皮ROS产生,而AR激活保护冠状动脉内皮血管舒张功能免受MGO诱导的损伤。尽管半乳糖凝集素-3的上调通过siRNA敲除在内皮细胞中证实不参与MGO诱导的内皮细胞凋亡,半乳糖凝集素-3的药物抑制剂进一步增强了MGO触发的ROS生成和冠状动脉内皮损伤。
结论：我们的数据表明AR下调-ROS过度产生-cPLA2激活途径是糖尿病CMD的潜在机制之一，并推测CMD相关性心绞痛性别差异的可能原因。同时,MGO诱导的半乳糖凝集素-3激活对冠状动脉内皮功能障碍具有代偿作用。
结果：由于糖尿病引起的甲基乙二醛（MGO）积累促进血管损伤，并用于模仿糖尿病状态。采用流式细胞术分析和等距张力测量评价冠状动脉内皮损伤。MGO诱导冠状动脉内皮细胞凋亡,伴随雄激素受体（AR）的下调。慢病毒介导的AR在冠状动脉内皮细胞中的稳定表达增加了抗凋亡Bcl-2的表达并减弱了MGO诱导的细胞凋亡。cPLA2激活是MGO处理下调AR的下游。此外，MGO还快速激活cPLA2以损害来自小鼠的冠状动脉的内皮依赖性血管舒张。证明了活性氧（ROS）的过度产生是MGO介导的cPLA2活化和内皮功能障碍的原因。重要的是,AR阻断增加内皮ROS产生,而AR激活保护冠状动脉内皮血管舒张功能免受MGO诱导的损伤。尽管半乳糖凝集素-3的上调通过siRNA敲除在内皮细胞中证实不参与MGO诱导的内皮细胞凋亡,半乳糖凝集素-3的药物抑制剂进一步增强了MGO触发的ROS生成和冠状动脉内皮损伤。
结论：我们的数据表明AR下调-ROS过度产生-cPLA2激活途径是糖尿病CMD的潜在机制之一，并推测CMD相关性心绞痛性别差异的可能原因。同时,MGO诱导的半乳糖凝集素-3激活对冠状动脉内皮功能障碍具有代偿作用。
