NCOA4-Mediated Ferroptosis in Bronchial Epithelial Cells Promotes Macrophage M2 Polarization in COPD Emphysema

Abstract

Background

Macrophage polarization plays an important role in the pathogenesis of COPD emphysema. Changes in macrophage polarization in COPD remain unclear, while polarization and ferroptosis are essential factors in its pathogenesis. Therefore, this study investigated the relationship between macrophage polarization and ferroptosis in COPD emphysema.

Methods

We measured macrophage polarization and the levels of matrix metalloproteinases (MMPs) in the lung tissues of COPD patients and cigarette smoke (CS)-exposed mice. Flow cytometry was used to determine macrophage (THP-M cell) polarization changes. Ferroptosis was examined by FerroOrange, Perls’ DAB, C11-BODIPY and 4-HNE staining. Nuclear receptor coactivator 4 (NCOA4) was measured in the lung tissues of COPD patients and CS-exposed mice by western blotting. A cell study was performed to confirm the regulatory effect of NCOA4 on macrophage polarization.

Results

Increased M2 macrophages and MMP9 and MMP12 levels were observed in COPD patients, CS-exposed mice and THP-M cells cocultured with CS extract (CSE)-treated human bronchial epithelial (HBE) cells. Increased NCOA4 levels and ferroptosis were confirmed in COPD. Treatment with NCOA4 siRNA and the ferroptosis inhibitor ferrostatin-1 revealed an association between ferroptosis and M2 macrophages. These findings support a role for NCOA4, which induces an increase in M2 macrophages, in the pathogenesis of COPD emphysema.

Conclusion

In our study, CS led to the dominance of the M2 phenotype in COPD. We identified NCOA4 as a regulator of M2 macrophages and emphysema by mediating ferroptosis, which offers a new direction for research into COPD diagnostics and treatment.

Keywords:

• NCOA4
• ferroptosis
• macrophage polarization
• MMP9
• MMP12
• COPD

Data Sharing Statement

All data generated or analyzed during this study are included in this published article [and its Supplementary Information Files].

Ethics Approval and Consent to Participate

All experimental work was approved by the ethical review board of Wuxi People’s Hospital Affiliated to Nanjing Medical University. This study was conducted in accordance with the tenets of the Declaration of Helsinki. The procedures for the care and use of animals were approved by the Ethics Committee of Nanjing Medical University (KY21033). The animals used in this study were maintained in accordance with the ethical guidelines of the Guiding Principles in the Care and Use of Animals (China) and the Policy of Animal Care and Use Committee of Nanjing Medical University. Humane care was provided according to the 3R principles of animal experiments.

Author Contributions

All authors made a significant contribution to the work reported, whether in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all of these areas. All authors took part in drafting, revising or critically reviewing the article, gave final approval of the version to be published, have agreed on the journal to which the article has been submitted and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests.

Additional information

Funding

This work was supported by the Natural Science Foundations of China (82173472), the project of the Translational Medicine Program of Wuxi City, Jiangsu Province (2020ZHYB13), the projects of the Health Department of Wuxi City, Jiangsu Province (M202032) and the Top Talent Support Program for young and middle-aged people of Wuxi Health Committee (BJ2020006).