ANAPC5 mitigates acute lung injury through regulating macrophage M1/M2 polarization via the EGFR/CD24 axis.

Acute lung injury (ALI) is a respiratory disease induced by uncontrolled inflammatory responses in the lungs. The pathological features of ALI include alveolar structural damage and pulmonary edema, which ultimately leads to pulmonary dysfunction. ANAPC5 (Anaphase-promoting complex subunit 5) is an E3 ubiquitin ligase known for its anti-inflammatory properties. This study aims to investigate the effects of ANAPC5 on ALI and its underlying molecular mechanism. In the lung tissue of an ALI mouse model induced by lipopolysaccharide (LPS) administration, we observed downregulation of ANAPC5. Through both in vivo and in vitro experiments, we assessed the effect of ANAPC5 on lung injury by conducting pathological analysis and molecular biological detection. ANAPC5 overexpression alleviated inflammatory cell infiltration, reduced alveolar wall thickening, suppressed pulmonary inflammation, and decreased the levels of inflammatory cytokines in bronchoalveolar lavage fluid (BALF) and lung tissue of the ALI model. Moreover, ANAPC5 inhibited M1 polarization and promoted M2 polarization of macrophages both in vitro and in vivo. We also found that ANAPC5 significantly suppressed the activation and expression of the epidermal growth factor receptor (EGFR) through inducing its ubiquitination in macrophages. In LPS-induced M1 macrophages, the presence of EGFR significantly decreased CD24 expression, followed by reversing the inhibitory effects of ANAPC5 on inflammatory responses and macrophage polarization. Collectively, our findings suggest that ANAPC5 serves as a therapeutic molecular target that mitigates ALI through regulating macrophage M1/M2 polarization via the EGFR/CD24 axis.