Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 52 3 2023 03 02 563 574 Yiming Jiang Department of Emergency, The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, 213003, China Jinhai Wang Department of Emergency, The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, 213003, China He Zhang Department of Emergency, The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, 213003, China Yeping Min Department of Emergency, The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, 213003, China Tijun Gu Department of Emergency, The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, 213003, China 2022 08 19 2022 12 18 Background: Polarization of macrophages and miR-7 have been reported to greatly influence the progress of chronic obstructive pulmonary disease (COPD). However, the interaction is unclear. We aimed to investigate the role of miR-7 in the serum exosome of COPD, thus further revealing the underlying mechanism of COPD. Methods: The study was conducted in 2022 in The Affiliated Changzhou No.2 People’s Hospital of Nanjing Medical University, Changzhou, China. COPD mouse model was established. Macrophages were sorted by flow cytometry assay. ELISA kits were used to detect the levels of TNF-α and IL-6. Exosomes were identified by confocal microscopy and PKH67 staining. RT-qPCR and western blot assay were performed to determine the mRNA and protein expressions. H&E staining assay was used to assess the tissue injury. CCK-8 assay was applied to evaluate cell viability. Luciferase reporter assay was used to confirm the binding between PIM1 and miR-7.  Results: The exosomes derived from the COPD mice serum exerted high level of miR-7, which induced M1 differentiation of macrophages and increased the secretion of proinflammatory factors in vivo and in vitro. The effects of exosomes from COPD mice could be inhibited by miR-7 inhibitor. Bioinformatic prediction, luciferase reporter assay, and western blot assay showed an interaction between miR-7 and PIM1. Further examination showed that miR-7 regulated macrophage activation and differentiation to M1 via PIM1 in vitro. Conclusions: miR-7 from serum exosomes might exacerbate COPD by stimulating macrophage differentiation to M1, supplying a potential therapeutic target for COPD treatment.   https://ijph.tums.ac.ir/index.php/ijph/article/view/29596 https://ijph.tums.ac.ir/index.php/ijph/article/download/29596/7883