Department of Pathology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
Bioengineering Lab, Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, Japan.
PLoS One. 2023 Feb 17;18(2):e0281730. doi: 10.1371/journal.pone.0281730. eCollection 2023.
Inflammatory activity and hypoxia in atherosclerotic plaques are associated with plaque instability and thrombotic complications. Recent studies show that vascular cell metabolism affects atherogenesis and thrombogenicity. This study aimed to identify the metabolites in macrophage-rich unstable plaques that modulate atherogenesis and serve as potential markers of plaque instability. Atherosclerotic plaques were induced by balloon injury in the iliofemoral arteries of rabbits fed on a conventional or 0.5% cholesterol diet. At 3 months post-balloon injury, the arteries and cardiac tissues were subjected to histological, quantitative real-time polymerase chain reaction, and metabolomic analyses. The identified metabolite-related proteins were immunohistochemically analyzed in stable and unstable plaques from human coronary arteries. The factors modulating the identified metabolites were examined in macrophages derived from human peripheral blood mononuclear cells. Metabolomic analysis revealed that choline and guanine levels in macrophage-rich arteries were upregulated compared with those in non-injured arteries and cardiac tissues. Vascular choline levels, but not guanine levels, were positively correlated with the areas immunopositive for macrophages and tumor necrosis factor (TNF)-α and matrix metalloproteinase (MMP) 9 mRNA levels in injured arteries. In human coronary arteries, choline transporter-like protein (CTL) 1 was mainly localized to macrophages within plaques. The area that was immunopositive for CTL1 in unstable plaques was significantly higher than that in stable plaques. Intracellular choline levels were upregulated upon stimulation with TNF-α but were downregulated under hypoxia in cultured macrophages. Administration of choline upregulated the expression of TNF-α and CTL1 mRNA in cultured macrophages. The transfection of CTL1 small interfering RNA decreased CTL1, TNF-α, and MMP9 mRNA levels in cultured macrophages. These results suggest that choline metabolism is altered in macrophage-rich atherosclerotic lesions and unstable plaques. Thus, CTL1 may be potential markers of plaque instability.
动脉粥样硬化斑块中的炎症活动和缺氧与斑块不稳定和血栓并发症有关。最近的研究表明，血管细胞代谢会影响动脉粥样硬化形成和血栓形成。本研究旨在鉴定富含巨噬细胞的不稳定斑块中的代谢物，这些代谢物调节动脉粥样硬化形成，并可作为斑块不稳定的潜在标志物。通过对常规或 0.5%胆固醇饮食喂养的兔髂股动脉进行球囊损伤，诱导动脉粥样硬化斑块形成。球囊损伤 3 个月后，对动脉和心脏组织进行组织学、定量实时聚合酶链反应和代谢组学分析。在人类冠状动脉的稳定和不稳定斑块中，通过免疫组织化学分析鉴定出与代谢物相关的蛋白。在人外周血单核细胞来源的巨噬细胞中，研究了调节鉴定出的代谢物的因素。代谢组学分析显示，与未受伤的动脉和心脏组织相比，富含巨噬细胞的动脉中的胆碱和鸟嘌呤水平升高。血管胆碱水平与受伤动脉中巨噬细胞和肿瘤坏死因子（TNF）-α以及基质金属蛋白酶（MMP）9 mRNA 水平免疫阳性面积呈正相关，但鸟嘌呤水平无此相关性。在人类冠状动脉中，胆碱转运蛋白样蛋白（CTL）1 主要定位于斑块内的巨噬细胞。不稳定斑块中 CTL1 免疫阳性面积明显高于稳定斑块。在培养的巨噬细胞中，TNF-α刺激可上调细胞内胆碱水平，而缺氧则下调。在培养的巨噬细胞中，给予胆碱可上调 TNF-α和 CTL1 mRNA 的表达。CTL1 小干扰 RNA 的转染可降低培养的巨噬细胞中 CTL1、TNF-α和 MMP9 mRNA 的水平。这些结果表明，胆碱代谢在富含巨噬细胞的动脉粥样硬化病变和不稳定斑块中发生改变。因此，CTL1 可能是斑块不稳定的潜在标志物。
