Lu J, Xie L, Liu C, Zhang Q, Sun S
Department of Respiratory Medicine, the Third XiangYa Hospital of Central South University, Changsha, Hunan Province, China.
Scand J Immunol. 2017 Jun;85(6):395-405. doi: 10.1111/sji.12545.
Macrophages play an important role in the pathogenesis of COPD. Macrophage polarization towards the M2 phenotype has been observed in the lung tissues of COPD patients and cigarette smokers. The molecular basis of this process remains unclear, and it has not been completely illuminated in animal models of emphysema. In our study, we combined cigarette smoke (CS) exposure with intraperitoneal injection of cigarette smoke extract (CSE) to build an emphysema model. We found by immunohistochemical staining and flow cytometry that the expression level of CD206 and the ratio of M2 to M1 macrophages was increased in emphysematous mice. We also demonstrated that decreased protein level for phosphatase and tensin homology deleted on chromosome ten (PTEN) and increased total protein levels for phosphorylation -protein kinase B (p-AKT) in the lung tissue of emphysematous mice and in CSE-treated RAW264.7 cells. In both bone marrow-derived macrophages (BMDMs) from emphysematous mice and CSE-treated RAW264.7 cells, we observed by RT-PCR that the mRNA levels of M2 macrophage-related markers and cytokines were increased. Furthermore, M1 macrophage-related markers and cytokines were decreased. Meanwhile we treated BMDMs from emphysematous mice and CSE-treated RAW264.7 cells with the phosphoinositide 3-kinase (PI3K)/Akt inhibitor (LY294002), we observed a reduction in RNA levels of M2 macrophage-related markers and cytokines. In conclusion, we confirmed that macrophage M2 polarization was induced in emphysematous mice generated by CS exposure combined with intraperitoneal injection of CSE. We also showed that M2 polarization was mediated through PTEN/PI3k/AKT pathway activation.
巨噬细胞在慢性阻塞性肺疾病（COPD）的发病机制中起重要作用。在COPD患者和吸烟者的肺组织中已观察到巨噬细胞向M2表型极化。这一过程的分子基础仍不清楚，在肺气肿动物模型中也未完全阐明。在我们的研究中，我们将香烟烟雾（CS）暴露与腹腔注射香烟烟雾提取物（CSE）相结合，建立了肺气肿模型。通过免疫组织化学染色和流式细胞术，我们发现肺气肿小鼠中CD206的表达水平以及M2与M1巨噬细胞的比例增加。我们还证明，肺气肿小鼠肺组织和经CSE处理的RAW264.7细胞中，第10号染色体上缺失的磷酸酶和张力蛋白同源物（PTEN）的蛋白水平降低，磷酸化蛋白激酶B（p-AKT）的总蛋白水平升高。在来自肺气肿小鼠的骨髓源性巨噬细胞（BMDM）和经CSE处理的RAW264.7细胞中，通过逆转录-聚合酶链反应（RT-PCR）我们观察到M2巨噬细胞相关标志物和细胞因子的mRNA水平升高。此外，M1巨噬细胞相关标志物和细胞因子减少。同时，我们用磷酸肌醇3-激酶（PI3K）/蛋白激酶B（Akt）抑制剂（LY294002）处理来自肺气肿小鼠的BMDM和经CSE处理的RAW264.7细胞，我们观察到M2巨噬细胞相关标志物和细胞因子的RNA水平降低。总之，我们证实了在通过CS暴露联合腹腔注射CSE产生的肺气肿小鼠中诱导了巨噬细胞M2极化。我们还表明，M2极化是通过PTEN/PI3K/Akt途径激活介导的。
