Department of Physiology and Pathophysiology, School of Basic Medical Sciences; Hemorheology Center, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing 100191, China.
Theranostics. 2023 Aug 6;13(13):4392-4411. doi: 10.7150/thno.84427. eCollection 2023.
Increasing evidence suggests that hemodynamic disturbed flow induces endothelial dysfunction via a complex biological process so-called endothelial to mesenchymal transition (EndoMT). Recently, DNA methyltransferases (DNMTs) was reported as a key molecular mediator to promote EndoMT. Our understanding of how DNMTs, particularly the maintenance DNMTs, DNMT1, coordinate EndoMT is still lacking. A parallel-plate flow apparatus and perfusion devices were used to apply fluid with endothelial protective pulsatile shear (PS, to mimic the laminar flow) or harmful oscillatory shear (OS, to mimic the disturbed flow) to cultured endothelial cells (ECs). Endothelial lineage tracing mice and conditional EC Dnmt1 knockout mice were subjected to a surgery of carotid partial ligation to generate the flow-accelerated atherogenesis models. Western blotting, quantitative RT-PCR, immunofluorescent staining, methylation-specific PCR, chromatin immunoprecipitation, endothelial functional assays, and assessments for neointimal formation and atherosclerosis were performed. Inhibition of DNMTs with 5-aza-2'-deoxycytidine (5-Aza) suppressed the disturbed flow/OS-induced EndoMT, both in cultured cells and the endothelial lineage tracing mice. 5-Aza also ameliorated the downregulation of aldehyde dehydrogenases (ALDHs) and β-alanine biosynthesis caused by disturbed flow/OS. Knockdown of the ALDH family proteins, ALDH2, ALDH3A1, and ALDH6A1, showed an EndoMT-induction effect as OS. Supplementation of cells with the functional metabolites of β-alanine, carnosine and acetyl-CoA (acetate), reversed EndoMT, likely via inhibiting the phosphorylation of Smad2/3. Endothelial-specific knockout of Dnmt1 protected the vasculature from disturbed flow-induced remodeling and atherosclerosis. Endothelial DNMT1 acts as one of the key epigenetic factors to mediate the hemodynamically regulated EndoMT at least through repressing the expression of ALDH2, ALDH3A1, and ALDH6A1. Supplementation with carnosine and acetate may have a great potential in the prevention and treatment of atherosclerosis.
越来越多的证据表明，血流动力学紊乱会通过一种复杂的生物学过程诱导内皮功能障碍，即所谓的内皮向间充质转化（EndoMT）。最近，DNA 甲基转移酶（DNMTs）被报道为促进 EndoMT 的关键分子介质。我们对 DNMTs，特别是维持 DNMTs、DNMT1 如何协调 EndoMT 的理解仍然不足。我们使用平行平板流动装置和灌注设备将具有内皮保护的脉动剪切（PS，模拟层流）或有害的振荡剪切（OS，模拟紊乱流）施加于培养的内皮细胞（ECs）。内皮谱系追踪小鼠和条件性 EC Dnmt1 敲除小鼠接受颈动脉部分结扎手术，以产生加速血流的动脉粥样硬化模型。进行 Western blot、定量 RT-PCR、免疫荧光染色、甲基化特异性 PCR、染色质免疫沉淀、内皮功能测定以及新生内膜形成和动脉粥样硬化评估。用 5-氮杂-2'-脱氧胞苷（5-Aza）抑制 DNMTs 可抑制培养细胞和内皮谱系追踪小鼠中紊乱流/OS 诱导的 EndoMT。5-Aza 还改善了紊乱流/OS 引起的醛脱氢酶（ALDHs）和β-丙氨酸生物合成的下调。ALDH 家族蛋白，如 ALDH2、ALDH3A1 和 ALDH6A1 的敲低，表现出 OS 诱导的 EndoMT 效应。用β-丙氨酸的功能代谢物肉毒碱和乙酰辅酶 A（乙酸盐）补充细胞，可通过抑制 Smad2/3 的磷酸化来逆转 EndoMT。内皮特异性 Dnmt1 敲除可保护血管免受紊乱流诱导的重塑和动脉粥样硬化。内皮 DNMT1 作为关键的表观遗传因子之一，至少通过抑制 ALDH2、ALDH3A1 和 ALDH6A1 的表达来介导血流调节的 EndoMT。肉毒碱和乙酸盐的补充可能具有预防和治疗动脉粥样硬化的巨大潜力。
