Xie Yinghua, Lou Danfei, Zhang Daimin
Department of Geriatrics, Fuzhou NO.1 Hospital Affiliated with Fujian Medical University, Fuzhou, Fujian, 350009, People's Republic of China.
Department of Geriatrics, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200071, People's Republic of China.
J Inflamm Res. 2021 Dec 11;14:6799-6812. doi: 10.2147/JIR.S329020. eCollection 2021.
Atherosclerosis is an aging-related disease, partly attributed to telomerase dysfunction. This study aims to investigate whether telomere dysfunction-related vascular aging is involved in the protection mechanism of melatonin (MLT) in atherosclerosis.
Young and aged ApoE mice were used to establish atherosclerotic mice model. H&E staining and immunofluorescence assay were performed to detect endothelial cell injury and apoptosis. Inflammatory cytokines and oxidative stress-related factors were determined using corresponding commercial assay kits. Telomerase activity was detected by TRAP assay, and SA-β-gal staining was conducted to evaluate cellular senescence. HUVECs were treated with HO for 1 h to induce senescence. Western blot was performed to measure protein expression.
An obvious vascular endothelial injury, reflected by excessive production of inflammatory cytokines, elevated ROS, MDA and SOD levels, and more apoptotic endothelial cells, was found in atherosclerotic mice, especially in aged mice, which were then greatly suppressed by MLT. In addition, telomere dysfunction and senescence occurred in atherosclerosis, especially in aged mice, while MLT significantly alleviated the conditions. CYP1A1, one of the targeted genes of MLT, was verified to be upregulated in atherosclerotic mice but downregulated by MLT. Furthermore, HO induced a senescence model in HUVECs, which was accompanied with a remarkably increased cell viability loss and apoptosis rate, and a downregulated telomerase activity of HUVECs, and this phenomenon was strengthened by RHPS4, an inhibitor of telomerase activity. However, MLT could partly abolish these changes in HO- and RHPS4-treated HUVECs, demonstrating that MLT alleviated vascular endothelial injury by regulating senescence and telomerase activity.
Collectively, this study provided evidence for the protective role of MLT in atherosclerosis through regulating telomere dysfunction-related vascular aging.
动脉粥样硬化是一种与衰老相关的疾病，部分归因于端粒酶功能障碍。本研究旨在探讨端粒功能障碍相关的血管衰老是否参与褪黑素（MLT）对动脉粥样硬化的保护机制。
使用年轻和老年载脂蛋白E小鼠建立动脉粥样硬化小鼠模型。进行苏木精-伊红（H&E）染色和免疫荧光分析以检测内皮细胞损伤和凋亡。使用相应的商业检测试剂盒测定炎性细胞因子和氧化应激相关因子。通过端粒重复序列扩增法（TRAP）检测端粒酶活性，并进行衰老相关β-半乳糖苷酶（SA-β-gal）染色以评估细胞衰老。用羟基脲（HO）处理人脐静脉内皮细胞（HUVECs）1小时以诱导衰老。进行蛋白质印迹法检测蛋白质表达。
在动脉粥样硬化小鼠中，尤其是老年小鼠中，发现明显的血管内皮损伤，表现为炎性细胞因子过度产生、活性氧（ROS）、丙二醛（MDA）和超氧化物歧化酶（SOD）水平升高以及更多的凋亡内皮细胞，而MLT可显著抑制这些损伤。此外，动脉粥样硬化中出现端粒功能障碍和衰老，尤其是在老年小鼠中，而MLT可显著改善这些情况。MLT的靶基因之一细胞色素P450 1A1（CYP1A1）在动脉粥样硬化小鼠中被证实上调，但被MLT下调。此外，HO诱导HUVECs衰老模型，伴随着细胞活力丧失和凋亡率显著增加以及HUVECs端粒酶活性下调，而端粒酶活性抑制剂RHPS4可增强这种现象。然而，MLT可部分消除HO和RHPS4处理的HUVECs中的这些变化，表明MLT通过调节衰老和端粒酶活性减轻血管内皮损伤。
总体而言，本研究为MLT通过调节端粒功能障碍相关的血管衰老在动脉粥样硬化中的保护作用提供了证据。
