Department of Translational Medical Sciences, Section of Cardiology, University of Campania "Luigi Vanvitelli", c/o Monaldi Hospital, Via L. Bianchi, 1, 80131 Naples, Italy.
Department of Advanced Biomedical Sciences, Section of Cardiology, University of Naples "Federico II", Naples, Italy.
Cardiovasc Res. 2020 May 1;116(6):1125-1135. doi: 10.1093/cvr/cvz230.
T-lymphocytes plays an important role in the pathophysiology of acute coronary syndromes. T-cell activation in vitro by pro-inflammatory cytokines may lead to functional tissue factor (TF) expression, indicating a possible contribution of immunity to thrombosis. Oxidized low-density lipoproteins (oxLDLs) are found abundantly in atherosclerotic plaques. We aimed at evaluating the effects of oxLDLs on TF expression in T cells and the role of the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1).
CD3+ cells were isolated from healthy volunteers. Gene, protein, and surface expression of TF, as well as of LOX-1, were assessed at different time-points after oxLDL stimulation. To determine whether oxLDL-induced TF was LOX-1 dependent, T cells were pre-incubated with an LOX-1 inhibiting peptide (L-RBP) or with an anti-LOX-1 blocking antibody. To exclude that TF expression was mediated by reactive oxygen species (ROS) generation, oxLDL-stimulated T cells were pre-incubated with superoxide dismutase + catalase or with 4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), an intracellular free radical scavenger. Finally, to determine if the observed findings in vitro may have a biological relevance, the presence of CD3+/TF+/LOX-1+ cells was evaluated by immunofluorescence in human carotid atherosclerotic lesions. oxLDLs induced functionally active TF expression in T cells in a dose- and time-dependent manner, independently on ROS generation. No effect was observed in native LDL-treated T cells. LOX-1 expression was also induced by oxLDLs in a time- and dose-dependent manner. Pre-incubation with L-RBP or anti-LOX-1 antibody almost completely inhibited oxLDL-mediated TF expression. Interestingly, human carotid plaques showed significant infiltration of CD3+ cells (mainly CD8+ cells), some of which were positive for both TF and LOX-1.
oxLDLs induce functional TF expression in T-lymphocytes in vitro via interaction of oxLDLs with LOX-1. Human carotid atherosclerotic plaques contain CD3+/CD8+cells that express both TF and LOX-1, indicating that also in patients these mechanisms may play an important role.
T 淋巴细胞在急性冠状动脉综合征的病理生理学中发挥重要作用。体外促炎细胞因子对 T 细胞的激活可能导致功能性组织因子（TF）表达，表明免疫可能有助于血栓形成。氧化型低密度脂蛋白（oxLDL）在动脉粥样硬化斑块中大量存在。我们旨在评估 oxLDL 对 T 细胞 TF 表达的影响，以及凝集素样氧化型低密度脂蛋白受体-1（LOX-1）的作用。
从健康志愿者中分离 CD3+细胞。在 oxLDL 刺激后不同时间点评估 TF 以及 LOX-1 的基因、蛋白和表面表达。为了确定 oxLDL 诱导的 TF 是否依赖于 LOX-1，T 细胞用 LOX-1 抑制肽（L-RBP）或抗 LOX-1 阻断抗体预先孵育。为了排除 TF 表达是由活性氧（ROS）生成介导的，用超氧化物歧化酶+过氧化氢酶或 4-羟基-2,2,6,6-四甲基哌啶-1-氧自由基（Tempol），一种细胞内自由基清除剂，预先孵育 oxLDL 刺激的 T 细胞。最后，为了确定体外观察到的发现是否具有生物学相关性，通过免疫荧光法评估人类颈动脉粥样硬化病变中 CD3+/TF+/LOX-1+细胞的存在。oxLDL 以剂量和时间依赖的方式诱导 T 细胞中功能性活性 TF 表达，而与 ROS 生成无关。用天然 LDL 处理的 T 细胞未观察到这种作用。oxLDL 也以时间和剂量依赖的方式诱导 LOX-1 表达。用 L-RBP 或抗 LOX-1 抗体预先孵育几乎完全抑制 oxLDL 介导的 TF 表达。有趣的是，人类颈动脉斑块显示出大量 CD3+细胞浸润（主要是 CD8+细胞），其中一些细胞同时表达 TF 和 LOX-1。
oxLDL 通过 oxLDL 与 LOX-1 的相互作用在体外诱导 T 淋巴细胞中功能性 TF 表达。人类颈动脉粥样硬化斑块含有同时表达 TF 和 LOX-1 的 CD3+/CD8+细胞，表明在患者中这些机制也可能发挥重要作用。
