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心肌梗死微环境中氧化低密度脂蛋白对树突状细胞诱导炎症反应的影响

Effect of oxidized low-density lipoprotein on dendritic cells-induced inflammation in microenvironment of myocardial infarction

  • 摘要: 目的:体外模拟高脂血症小鼠心肌梗死(myocardial infarction, MI)和肾素-血管紧张素系统(RAS)被激活的内环境,研究氧化低密度脂蛋白(ox-LDL)能否在血管紧张素Ⅱ(AngⅡ)的基础上进一步诱导树突状细胞(dendritic cells, DCs)的成熟、迁移和炎症反应,并探讨可能参与其中的信号通路。方法:诱导C57BL/6J小鼠骨髓细胞分化成DCs,然后加入坏死心肌细胞上清,分别给予AngⅡ和ox-LDL+AngⅡ干预48 h。流式细胞仪检测DCs的成熟标志物(CD83)和协同共刺激分子(CD86)的表达,用qPCR、ELISA方法测定炎性因子的表达。Western 印迹法检测核因子κB(NF-κB)和IκB磷酸化程度,以及血凝素样氧化型低密度脂蛋白受体-1(LOX-1)和Toll样受体(TLR)4信号通路的表达。结果:ox-LDL能够在AngⅡ基础上进一步诱导CD83和CD86的表达,增强炎性因子和趋化因子的表达,增强NF-κB和IκB磷酸化程度(P<0.05)。ox-LDL能够在AngⅡ基础上进一步上调LOX-1的表达,同时激活了TLR4-MyD88-NF-κB通路(P<0.05)。结论:ox-LDL可能在AngⅡ的基础上进一步诱导DCs免疫成熟、迁移和炎症反应;LOX-1-TLR4-MyD88-NF-κB信号通路可能参与DCs成熟,以及DCs在高脂血症合并心肌梗死发生和发展中引起炎症反应的过程。

     

    Abstract: Objective:To explore the induction of maturation, migration, and inflammation of dendritic cells (DCs) after treatment with angiotensin (Ang)Ⅱ via oxidized low-density lipoprotein (ox-LDL), and its corresponding signaling pathway. Methods:Bone marrow cells from C57BL/6J WT mice were differentiated into DCs. After adding supernatant of necrotic cardiomyocyte cells, DCs were treated with either AngⅡalone or in combination with ox-LDL for 48 h. CD83 and CD86 were measured via flow cytometry, while cytokines and chemokine levels were measured by the qPCR or ELISA. Nuclear factor κB (NF-κB) and IκB phosphorylation were detected by Western blotting. The expressions of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), myeloid differentiation factor 88 (MyD88), and Toll-like receptor (TLR)4 were detected by Western blotting. Results:Ox-LDL could further up-regulate the maturity marker CD83 and CD86 in DCs on the basis of AngⅡtreatment. The expressions of inflammatory factors and chemokines, as well as phosphorylation of NF-κB and IκB were upregulated (P<0.05). The expression of LOX-1, phosphorylation of interleukin-1 receptor associated kinase (IRAK)-4 and the activation of TLR4/MyD88 signaling pathway were further enhanced by ox-LDL (P<0.05). Conclusions:The immune maturation, migration, and inflammation of DCs treated with AngⅡcould be further induced by ox-LDL, possibly via the LOX-1-TLR4-MyD88 signaling pathway.

     

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