Reduced DNA methylation of sphingosine-1 phosphate receptor 5 in alveolar macrophages in COPD: A potential link to failed efferocytosis
Reduced DNA methylation of sphingosine-1 phosphate receptor 5 in alveolar macrophages in COPD: A potential link to failed efferocytosis
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DOI：
10.1111/resp.12949
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发表时间：
2017-02-01
期刊：
影响因子：
6.9
通讯作者：
Meech, Robyn
中科院分区：
文献类型：
--
作者：
Barnawi, Jameel;Jersmann, Hubertus;Meech, Robyn
背景和目的：我们先前表明，COPD患者的肺泡巨噬细胞吞噬凋亡细胞的能力有缺陷（“细胞吞噬”），并且这种缺陷可能与1-磷酸鞘氨醇（S1 P）系统，特别是1-磷酸鞘氨醇受体5（S1 PR 5）有关。在COPD患者的肺泡巨噬细胞中，S1 PR 5 mRNA表达水平增加，并与肺功能和红细胞增多相关。然而，我们不知道这些变化是否通过DNA甲基化受到表观遗传学控制，或者DNA甲基化是否直接调节巨噬细胞功能。使用亚硫酸氢盐测序来评估与编码来自20名COPD患者的肺泡巨噬细胞中的选定S1 P系统组分（包括鞘氨醇激酶1（SPHK 1）、S1 PR 1和S1 PR 5）的基因相关的CpG岛处的DNA甲基化水平，7名健康吸烟者和10名健康非吸烟者/前吸烟者）通过甲基定量实时PCR（甲基qPCR）。DNA甲基转移酶抑制剂，5-氮胞苷对THP-1巨噬细胞的吞噬能力的影响进行了评估，使用流式cytometry.Results：在S1 P系统基因检查，S1 PR 5是单一的目标，表现出显着的变化，患者组之间的DNA甲基化。从COPD患者中分离的肺泡巨噬细胞与来自非吸烟者/戒烟者的巨噬细胞相比在相同区域中显示出较低的甲基化水平。THP-1巨噬细胞的体外研究表明，5-氮胞苷的DNA去甲基化增加了巨噬细胞的吞噬能力，并剂量依赖性地拯救了细胞从香烟烟雾诱导的缺陷中的吞噬功能。甲基化水平降低可能是COPD患者肺泡巨噬细胞S1 PR 5基因表达增加和相关缺陷性巨噬细胞增多的基础。
Background and objective: We previously showed that alveolar macrophages from COPD patients are defective in their ability to phagocytose apoptotic cells ('efferocytosis') and that this defect is potentially linked to the sphingosine-1 phosphate (S1P) system, in particular the sphingosine-1 phosphate receptor 5 (S1PR5). In alveolar macrophages from COPD patients, S1PR5 mRNA expression levels increased and were correlated with both lung function and efferocytosis. However, it us unknown whether these changes are under epigenetic control via DNA methylation or whether DNA methylation directly modulates macrophage function.Methods: Bisulfite sequencing was used to assess DNA methylation levels at CpG islands associated with genes encoding selected S1P system components, including sphingosine kinase 1 (SPHK1), S1PR1 and S1PR5, in alveolar macrophages from 20 COPD patients, 7 healthy smokers and 10 healthy non/ex-smokers) by methyl quantitative real-time PCR (methyl qPCR). The effect of the DNA methyltransferase inhibitor, 5-azacytidine on the efferocytosis capacity of THP-1 macrophages was assessed using flow cytometry.Results: Among the S1P system genes examined, S1PR5 was the single target that showed significant changes in DNA methylation between patient groups. Alveolar macrophages isolated from COPD patients showed lower methylation levels in the same region compared to macrophages from non/ex-smokers. in vitro studies using THP-1 macrophages showed that DNA demethylation with 5-azacytidine increased the efferocytosis capacity and dose-dependently rescued the cells from the cigarette smoke-induced defect in efferocytosis.Conclusion: Macrophage function can be modulated epigenetically. Reduced methylation may underlie the increased expression of the S1PR5 gene in alveolar macrophages and associated defective efferocytosis in COPD.