From the Immunology and Allergy Unit (A.-L.J., C.S., S.L., J.A.).
Department of Medicine Solna, and Department of Microbiology, Tumor and Cell Biology (N.V.K., L.S.W.), Karolinska Institutet, Stockholm, Sweden.
Circ Res. 2018 May 11;122(10):1385-1394. doi: 10.1161/CIRCRESAHA.117.312340. Epub 2018 Apr 4.
Regulatory T (Treg) cells suppress immune responses and have been shown to attenuate atherosclerosis. The Treg cell lineage-specification factor FOXP3 (forkhead box P3) is essential for Treg cells' ability to uphold immunologic tolerance. In humans, FOXP3 exists in several different isoforms, however, their specific role is poorly understood.
To define the regulation and functions of the 2 major FOXP3 isoforms, FOXP3fl and FOXP3Δ2, as well as to establish whether their expression is associated with the ischemic atherosclerotic disease.
Human primary T cells were transduced with lentiviruses encoding distinct FOXP3 isoforms. The phenotype and function of these cells were analyzed by flow cytometry, in vitro suppression assays and RNA-sequencing. We also assessed the effect of activation on Treg cells isolated from healthy volunteers. Treg cell activation resulted in increased FOXP3 expression that predominantly was made up of FOXP3Δ2. FOXP3Δ2 induced specific transcription of GARP (glycoprotein A repetitions predominant), which functions by tethering the immunosuppressive cytokine TGF (transforming growth factor)-β to the cell membrane of activated Treg cells. Real-time polymerase chain reaction was used to determine the impact of alternative splicing of in relation with atherosclerotic plaque stability in a cohort of >150 patients that underwent carotid endarterectomy. Plaque instability was associated with a lower transcript usage, when comparing plaques from patients without symptoms and patients with the occurrence of recent (<1 month) vascular symptoms including minor stroke, transient ischemic attack, or amaurosis fugax. No difference was detected in total levels of mRNA between these 2 groups.
These results suggest that activated Treg cells suppress the atherosclerotic disease process and that FOXP3Δ2 controls a transcriptional program that acts protectively in human atherosclerotic plaques.
调节性 T（Treg）细胞抑制免疫反应，并已被证明可减轻动脉粥样硬化。Treg 细胞谱系特异性因子 FOXP3（叉头框 P3）对于 Treg 细胞维持免疫耐受的能力至关重要。在人类中，FOXP3 存在几种不同的异构体，但它们的具体作用尚未完全阐明。
定义 2 种主要 FOXP3 异构体 FOXP3fl 和 FOXP3Δ2 的调节和功能，并确定其表达是否与缺血性动脉粥样硬化疾病相关。
通过慢病毒转导人原代 T 细胞，分别编码不同的 FOXP3 异构体。通过流式细胞术、体外抑制试验和 RNA 测序分析这些细胞的表型和功能。我们还评估了激活对从健康志愿者中分离的 Treg 细胞的影响。Treg 细胞的激活导致 FOXP3 表达增加，主要由 FOXP3Δ2 组成。FOXP3Δ2 诱导 GARP（糖蛋白 A 重复为主）的特异性转录，该蛋白通过将免疫抑制性细胞因子 TGF（转化生长因子）-β 与激活的 Treg 细胞膜结合而发挥作用。实时聚合酶链反应用于确定在接受颈动脉内膜切除术的 150 多名患者的队列中，与动脉粥样硬化斑块稳定性相关的 剪接方式的影响。与无症状患者的斑块相比，斑块不稳定性与较低的 转录物使用相关，而无症状患者的斑块来自于近期（<1 个月）发生血管症状（包括小中风、短暂性脑缺血发作或一过性黑矇）的患者。这两组之间未检测到 mRNA 的总水平有差异。
这些结果表明，激活的 Treg 细胞抑制动脉粥样硬化疾病进程，FOXP3Δ2 控制着在人类动脉粥样硬化斑块中起保护作用的转录程序。
