Yang Jinjing, Ma Xiurui, Niu Dan, Sun Yu, Chai Xiaohong, Deng Yongzhi, Wang Jingping, Dong Jin
Department of Cardiology, Shanxi Cardiovascular Hospital Taiyuan 030024, Shanxi, China.
Shanxi Cardiovascular Institute Taiyuan 030024, Shanxi, China.
Am J Transl Res. 2023 Aug 15;15(8):5129-5144. eCollection 2023.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, a novel class of cholesterol-lowering drugs, can reduce atherosclerosis independent of systemic lipid changes. However, the mechanism by which PCSK9 inhibition protects against arteriosclerosis has not been fully elucidated. Recent evidence has demonstrated a correlation between PCSK9 inhibitors and oxidative stress, which accelerates atherosclerotic development. Moreover, an increasing number of studies have shown that autophagy protects the vasculature against atherosclerosis. Therefore, the aims of this study were to investigate the effect of PCSK9 inhibition on oxidative stress and autophagy in atherosclerosis and determine whether autophagy regulates PCSK9 inhibition-mediated oxidative stress and inflammation in macrophages.
Male apolipoprotein E (ApoE) mice were fed a high-fat diet (HFD) for 8 weeks and then received the PCSK9 inhibitor (evolocumab), vehicle, or evolocumab plus chloroquine (CQ) for another 8 weeks. ApoE mice in the control group were fed a regular (i.e., non-high-fat) diet for 16 weeks. Additional experiments were performed in oxidized low-density lipoprotein (ox-LDL)-treated human acute monocytic leukemia cell line THP-1-derived macrophages to mimic the pathophysiologic process of atherosclerosis.
PCSK9 inhibitor treatment reduced oxidative stress, lipid deposition, and plaque lesion area and induced autophagy in HFD-fed ApoE mice. Most importantly, the administration of chloroquine (CQ), an autophagy inhibitor, significantly reduced the beneficial effects of PCSK9-inhibitor treatment on oxidative stress, lipid accumulation, inflammation, and atherosclerotic lesions in HFD-fed ApoE mice. The experiments further showed that the PCSK9 inhibitor enhanced autophagic flux in ox-LDL-treated THP-1-derived macrophages, as indicated by increases in the numbers of autophagosomes and autolysosomes. Moreover, the autophagy inhibitor CQ also reduced PCSK9 inhibition-mediated protection against oxidative stress, generation of reactive oxygen species (ROS) and inflammation in ox-LDL-treated THP-1-derived macrophages.
This study reveals a novel protective mechanism by which PCSK9 inhibition enhances autophagy and thereby reduces oxidative stress and inflammation in atherosclerosis.
前蛋白转化酶枯草溶菌素/kexin 9型（PCSK9）抑制剂是一类新型的降胆固醇药物，可独立于全身脂质变化减轻动脉粥样硬化。然而，PCSK9抑制预防动脉硬化的机制尚未完全阐明。最近的证据表明PCSK9抑制剂与氧化应激之间存在关联，氧化应激会加速动脉粥样硬化的发展。此外，越来越多的研究表明自噬可保护血管免受动脉粥样硬化影响。因此，本研究旨在探讨PCSK9抑制对动脉粥样硬化中氧化应激和自噬的影响，并确定自噬是否调节PCSK9抑制介导的巨噬细胞氧化应激和炎症反应。
雄性载脂蛋白E（ApoE）小鼠喂食高脂饮食（HFD）8周，然后再接受PCSK9抑制剂（依洛尤单抗）、赋形剂或依洛尤单抗加氯喹（CQ）治疗8周。对照组的ApoE小鼠喂食常规（即非高脂）饮食16周。在氧化型低密度脂蛋白（ox-LDL）处理的人急性单核细胞白血病细胞系THP-1衍生的巨噬细胞中进行额外实验，以模拟动脉粥样硬化的病理生理过程。
PCSK9抑制剂治疗可减轻喂食HFD的ApoE小鼠的氧化应激、脂质沉积和斑块病变面积，并诱导自噬。最重要的是，自噬抑制剂氯喹（CQ）的给药显著降低了PCSK9抑制剂治疗对喂食HFD的ApoE小鼠氧化应激、脂质积累、炎症和动脉粥样硬化病变的有益作用。实验进一步表明，PCSK9抑制剂增强了ox-LDL处理的THP-1衍生巨噬细胞中的自噬通量，这表现为自噬体和自溶酶体数量增加。此外，自噬抑制剂CQ也降低了PCSK9抑制介导的对ox-LDL处理的THP-1衍生巨噬细胞氧化应激、活性氧（ROS）生成和炎症的保护作用。
本研究揭示了一种新的保护机制，即PCSK9抑制增强自噬，从而减轻动脉粥样硬化中的氧化应激和炎症反应。
