癸酸通过Sestrin2-AMPK信号通路影响平滑肌细胞氧化应激性凋亡改善主动脉夹层血管重构的机制研究

Aortic dissection (AD) is a fatal vascular disease characterized by acute onset, the mechanism of vascular remodeling of AD needs to be clarified. From the perspective of of systems biology, metabolomic analysis of plasma metabolites was performed in our previous study by gas chromatography combined with time of flight mass spectrometry metabolomics analysis (GC-TOF/MS), screening metabolites that have significant difference in AD patients compared with abdominal aortic aneurysm patients and healthy people, establishing the metabolic map of AD, so as to explore the possible pathologic process involved. Metabonomics results showed that a variety of abnormal content of reducing substances existed in serum of AD patients and a fatty acid, decanoic acid (DA) was significantly decreased in AD patients compared with the control group. Animal experiments showed that DA could reduce the incidence of AD and improve vascular remodeling. In order to explore the mechanism involved, we established quantitative proteomics screening of proteins expressed differentially in vascular smooth muscle cells (SMCs) treated by decanoic acid, and we found that Sestrin2 protein content increased significantly after decanoic acid treatment, the differential proteins were significantly enriched in the biological process of oxidative stress, cell apoptosis and the regulation of AMPK pathway. The apoptosis of SMCs induced by oxidative stress is an important factor leading to the remodeling of AD. So we proposed that DA might affect the oxidative stress and the apoptosis of smooth muscle cells through Sestrin2-AMPK pathway, and then improve the vascular remodeling of AD. Therefore, in this study we intend to confirm that DA inhibit oxidative stress and apoptosis of smooth muscle cells through the Sestrin2-AMPK pathway in vitro, and utilize the animal models to prove that DA improve vascular remodeling of AD through the Sestrin2-AMPK pathway. The results of this study may provide new ideas for the discovery of the mechanism of AD development and provide new targets and strategies for the early prevention and comprehensive treatment of AD.

主动脉夹层（AD）起病急骤、病情凶险，其血管重构机制亟待阐明。预研究从系统生物学角度出发，应用气相色谱结合飞行时间质谱法建立AD血清学代谢谱并发现癸酸含量在AD患者血清中特异性降低；已通过小鼠夹层造模实验证明癸酸可降低AD发生率并改善血管重构；为探究机制，我们通过定量蛋白组学筛查了癸酸作用于平滑肌细胞（SMC）后的差异表达蛋白，发现Sestrin2蛋白含量显著升高，差异蛋白显著富集于氧化应激和细胞凋亡过程以及AMPK通路的调控。氧化应激引起的SMC凋亡是造成AD血管重构的重要因素，因此我们提出：癸酸可能通过活化Sestrin2-AMPK通路抑制SMC氧化应激性凋亡进而改善AD血管重构。本项目拟在细胞水平探究癸酸可否通过该通路抑制SMC氧化应激性凋亡；在动物模型中探究癸酸是否通过该通路影响AD血管重构。研究结果将可能揭示AD发生发展的新机制，进而为AD的早期预防和综合治疗提供新靶标和新策略。

主动脉夹层（AD）起病急骤、病情凶险，其血管重构机制亟待阐明。课题组前期建立AD血清学代谢谱并发现癸酸含量在AD患者血清中特异性降低；并通过小鼠夹层造模实验证明癸酸可降低AD发生率并改善血管重构；定量蛋白组学筛查发现癸酸作用于平滑肌细胞（SMC）后Sestrin2蛋白含量显著升高，且差异蛋白显著富集于氧化应激和细胞凋亡过程以及AMPK通路调控，而氧化应激引起的SMC凋亡是造成AD血管重构的重要因素，为证实癸酸通过活化Sestrin2-AMPK通路抑制SMC氧化应激性凋亡进而减轻AD血管重构，本项目开展两部分研究：（1）细胞水平探究癸酸是否通过Sestrin2-AMPK通路抑制SMC氧化应激性凋亡：①癸酸干预SMC后检测Sestrin2-AMPK通路活化情况、氧化应激水平以及细胞凋亡情况；②癸酸干预Sestrin2沉默以及AMPK活性被抑制的SMC后检测细胞氧化应激水平和凋亡情况变化；（2）夹层模型小鼠中探究癸酸是否通过Sestrin2-AMPK通路影响AD血管重构：分别以正常饮食和富含癸酸饮食喂养正常和Sestrin2基因敲减的C57BL/6小鼠，按照β-氨基丙腈结合AngII的方法进行主动脉夹层造模后，取主动脉组织样本检测Sestrin2-AMPK通路活化状态、氧化应激水平和SMC凋亡情况。研究结果发现：①SMC中癸酸可活化Sestrin2-AMPK信号通路，抑制氧化应激性细胞凋亡；Sestrin2基因沉默及AMPK活性抑制后，癸酸抑制SMC氧化应激性凋亡的作用受抑制；②小鼠中Sestrin2基因敲减后，癸酸对主动脉夹层的保护作用受抑制。得出结论：癸酸抑制主动脉夹层发生发展的机制为促进Sestrin2蛋白表达，增强AMPK磷酸化，保护细胞免受氧化应激损伤，从而减少中膜SMC凋亡，减轻主动脉夹层血管重构。该研究结果将可能揭示AD发生发展的新机制，进而为AD的早期预防和综合治疗提供新靶标和新策略。

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