Department of Cardiology and Angiology, University Hospital Erlangen, Germany.
Atherosclerosis. 2013 Sep;230(1):92-9. doi: 10.1016/j.atherosclerosis.2013.06.014. Epub 2013 Jul 10.
Mature dendritic cells (DCs) play a crucial role in the inflammatory process within atherosclerotic lesions by stimulation of effector T cells, which can contribute to plaque instability. Interactions between DCs and regulatory T cells (Treg), which regulate immune response by attenuating acute inflammation, are postulated to be involved in the pathogenesis of autoimmune diseases. We investigated a possible correlation between infiltrated DCs and Treg in human atherosclerotic plaques.
Cross-sections of 40 human carotid endarterectomy specimens were classified into groups of stable and vulnerable plaques using Trichrome staining. Immunohistochemical staining of plaques was used to detect infiltrated total (S100) and mature DCs (fascin, DC-LAMP, CD83), Treg (CD3, Foxp3), and to analyze the inflammatory state of the plaques (CD3, COX-2, CD68). In addition, RNA was isolated from plaque specimens and quantitative real-time PCR was performed to analyze transcription rates of DC markers (CD11c, CD209, HLA-DR), maturation markers (CD80, CD83, CD86), Treg-associated genes (CTLA-4, Foxp3) and of pro- and anti-inflammatory cytokines (TGFβ-family, IL-10, IFN-γ, IL-17α, IL-6). Migration assays and adhesion experiments were performed, to investigate the effects of Treg on mature DCs in vitro.
As compared with stable plaques, vulnerable lesions were characterized by increased numbers of COX-2-expressing cells and T lymphocytes, indicating an enhanced inflammatory process. In vulnerable plaques, numbers of total and mature DCs were significantly higher in the inflammatory plaque shoulder, whereas the numbers of Treg were decreased compared to stable plaques. This inverse correlation and the association of the observed infiltration rates with plaque stability, were confirmed by PCR analyses, showing increased transcription levels of DC-specific markers, decreased mRNA expression of Treg-associated genes and decreased anti-inflammatory cytokines in vulnerable atherosclerotic plaques. In vitro, pre-incubation of mature DCs with Treg resulted in decreased DC migration and inhibited the adhesion of DCs to endothelial cells under non-uniform shear stress.
The results of our study provide novel insights in the direct interaction of mature DCs and Treg in plaque inflammation and stability.
成熟树突状细胞（DC）通过刺激效应 T 细胞在动脉粥样硬化病变的炎症过程中发挥关键作用，这可能导致斑块不稳定。DC 与调节性 T 细胞（Treg）之间的相互作用被认为参与了自身免疫性疾病的发病机制，Treg 通过减轻急性炎症来调节免疫反应。我们研究了人类动脉粥样硬化斑块中浸润的 DC 和 Treg 之间可能存在的相关性。
使用三色染色将 40 个人颈动脉内膜切除术标本的切片分为稳定斑块组和易损斑块组。用免疫组织化学染色检测斑块中的浸润总（S100）和成熟 DC（fascin、DC-LAMP、CD83）、Treg（CD3、Foxp3），并分析斑块的炎症状态（CD3、COX-2、CD68）。此外，从斑块标本中分离 RNA，进行实时定量 PCR 分析，以分析 DC 标志物（CD11c、CD209、HLA-DR）、成熟标志物（CD80、CD83、CD86）、Treg 相关基因（CTLA-4、Foxp3）和促炎和抗炎细胞因子（TGFβ 家族、IL-10、IFN-γ、IL-17α、IL-6）的转录率。进行迁移实验和粘附实验，以研究 Treg 对体外成熟 DC 的影响。
与稳定斑块相比，易损斑块的 COX-2 表达细胞和 T 淋巴细胞数量增加，表明炎症过程增强。在易损斑块中，炎症斑块肩部的总 DC 和成熟 DC 数量明显高于稳定斑块，而 Treg 数量则低于稳定斑块。这种负相关以及观察到的浸润率与斑块稳定性的关联，通过 PCR 分析得到了证实，显示出易损动脉粥样硬化斑块中 DC 特异性标志物的转录水平增加，Treg 相关基因的 mRNA 表达减少，抗炎细胞因子减少。体外，成熟 DC 与 Treg 预孵育导致 DC 迁移减少，并抑制 DC 在非均匀剪切应力下黏附内皮细胞。
本研究结果提供了关于成熟 DC 和 Treg 在斑块炎症和稳定性中的直接相互作用的新见解。
