Institute for Clinical Chemistry and Laboratory Medicine, University Hospital of Regensburg, 93053 Regensburg, Germany.
Leibniz Institute for Arteriosclerosis Research, University of Muenster, 48149 Muenster, Germany.
Cytometry A. 2019 Aug;95(8):869-884. doi: 10.1002/cyto.a.23772. Epub 2019 Apr 17.
Ezetimibe (EZE) and glucuronidated EZE (EZE-Glu) differentially target Niemann-Pick C1-like 1 (NPC1L1) and CD13 (aminopeptidase-N) to inhibit intestinal cholesterol absorption and cholesterol processing in other cells, although the precise molecular mechanisms are not fully elucidated. Cellular effects of EZE, EZE-Glu, and the low-absorbable EZE-analogue S6130 were investigated on human monocyte-derived macrophages upon loading with atherogenic lipoproteins. EZE and S6130, but not EZE-Glu disturbed the colocalization of CD13 and its coreceptor CD64 (Fcγ receptor I) in membrane microdomains, and decreased the presence of both receptors in detergent-resistant membrane fractions. Biotinylated cholesterol absorption inhibitor C-5 (i.e., derivative of EZE) was rapidly internalized to perinuclear tubular structures of cells, resembling endoplasmic reticulum (ER), but CD13 was detected on extracellular sites of the plasma membrane and endolysosomal vesicles. Administration of EZE, but not of EZE-Glu or S6130, was associated with decreased cellular cholesteryl ester content, indicating the sterol-O acyltransferase 1 (SOAT1)-inhibition by EZE. Furthermore, EZE decreased the expression of molecules involved in cholesterol uptake and synthesis, in parallel with increased apolipoprotein A-I-mediated cholesterol efflux and upregulation of efflux-effectors. However, NPC1L1 the other claimed molecular target of EZE, was not detected in macrophages, thereby excluding this protein as target for EZE in macrophages. Thus, EZE is very likely a CD13-linked microdomain-disruptor and SOAT1-inhibitor in macrophages leading to in vitro anti-atherosclerotic effects through a decrease of net cellular cholesterol content. © 2019 International Society for Advancement of Cytometry.
依泽替米贝（EZE）和葡糖醛酸化的依泽替米贝（EZE-Glu）通过靶向尼曼-匹克 C1 样 1（NPC1L1）和 CD13（氨肽酶 N）来抑制肠道胆固醇吸收和其他细胞中的胆固醇加工，尽管确切的分子机制尚未完全阐明。在载脂蛋白致动脉粥样硬化脂蛋白负荷下人单核细胞衍生的巨噬细胞上研究了 EZE、EZE-Glu 和低吸收性 EZE 类似物 S6130 的细胞作用。EZE 和 S6130，但不是 EZE-Glu，扰乱了 CD13 与其核心受体 CD64（Fcγ 受体 I）在膜微域中的共定位，并减少了两种受体在去污剂抗性膜部分中的存在。生物素化胆固醇吸收抑制剂 C-5（即 EZE 的衍生物）迅速被内化到细胞的核周管状结构中，类似于内质网（ER），但 CD13 在外周质膜和内溶酶体小泡的细胞外部位被检测到。EZE 的给药，而不是 EZE-Glu 或 S6130 的给药，与细胞胆固醇酯含量的减少相关，表明 EZE 抑制甾醇-O-酰基转移酶 1（SOAT1）。此外，EZE 降低了参与胆固醇摄取和合成的分子的表达，同时增加了载脂蛋白 A-I 介导的胆固醇流出和流出效应物的上调。然而，巨噬细胞中未检测到 NPC1L1，即 EZE 的另一个声称的分子靶标，从而排除了该蛋白作为巨噬细胞中 EZE 的靶标。因此，EZE 很可能是巨噬细胞中的 CD13 相关微域破坏剂和 SOAT1 抑制剂，通过降低净细胞胆固醇含量在体外发挥抗动脉粥样硬化作用。
