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Updated: Mar 6, 2026
Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages
Published on: June 23, 2013
PTEN/PI3k/AKT Regulates Macrophage Polarization in Emphysematous mice
1Department of Respiratory Medicine, the Third XiangYa Hospital of Central South University, Changsha, Hunan Province, China.
Abstract:
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.
Insights
This study shows cigarette smoke induces M2 macrophage polarization in emphysema via the PTEN/PI3K/AKT pathway. This finding clarifies a key mechanism in chronic obstructive pulmonary disease pathogenesis.
Area of Science:
- Immunology
- Pulmonology
- Cell Biology
Background:
- Macrophages are crucial in chronic obstructive pulmonary disease (COPD) pathogenesis.
- M2 macrophage polarization is observed in COPD patients and smokers, but its molecular basis is unclear.
- Existing animal models of emphysema lack detailed illumination of this process.
Purpose of the Study:
- To investigate the molecular mechanisms of M2 macrophage polarization in an emphysema model.
- To elucidate the role of the PTEN/PI3K/AKT pathway in cigarette smoke-induced M2 polarization.
Main Methods:
- An emphysema model was created using cigarette smoke (CS) exposure and cigarette smoke extract (CSE) injection.
- Immunohistochemistry, flow cytometry, and RT-PCR were used to analyze macrophage phenotypes and marker expression.
- RAW264.7 cells and bone marrow-derived macrophages (BMDMs) were treated with CSE and a PI3K/Akt inhibitor (LY294002).
Main Results:
- Emphysematous mice exhibited increased CD206 expression and a higher M2/M1 macrophage ratio.
- Decreased PTEN and increased p-AKT protein levels were observed in lung tissue and CSE-treated cells.
- CSE treatment increased M2 markers and decreased M1 markers, which was reversed by LY294002.
Conclusions:
- Macrophage M2 polarization is induced in a CS-induced emphysema model.
- This M2 polarization is mediated by the activation of the PTEN/PI3K/AKT pathway.
