Azithromycin Mitigates Tobacco Smoke-Induced Lung Senescence by Modulating the FOXO3A/CCND1 Signaling Pathway

Accelerated lung aging is observed in chronic obstructive pulmonary disease (COPD), this study delved into the precise mechanisms through which azithromycin mitigated lung aging associated with COPD.

Employing network pharmacology, we predicted potential pathways through which azithromycin might affect COPD development. We collected lung tissues from non-smoking individuals, smokers with normal lung function, and smokers with COPD. COPD models were created by exposing mice to cigarette smoke (CS) for 24 weeks and stimulating human bronchial epithelial cells (BEAS-2B) with 0.2% cigarette smoke extract (CSE) for 24 hours. Azithromycin was then given to CS-exposed emphysema mice. BEAS-2B cells were pre-treated with azithromycin before being exposed to CSE and JY-2, a Forkhead box O3 (FOXO3A) inhibitor. Senescence-associated secretory phenotype (SASP) cytokines (interleukin-6, interleukin-8) in mouse BALF were quantified using ELISA. Markers associated with cellular aging (β-galactosidase activity, p53, and p21), FOXO3A, and Cyclin D1 (CCND1) were assessed via qPCR, Western blot, immunohistochemistry, and β-galactosidase staining.

COPD patients who smoked showed increased pulmonary expression of CCND1, p53, and p21, with decreased FOXO3A in comparison with other groups. Similarly, CS-exposed mouse lung tissue exhibited reduced FOXO3A and elevated p53, p21, and CCND1, along with higher SASP secretion in BALF. Azithromycin treatment lowered SASP secretion and decreased CCND1, p53, and p21 expression, while increasing FOXO3A. In BEAS-2B cells, CSE and JY-2 stimulation raised senescence markers and CCND1 while lowering FOXO3A. Azithromycin preconditioning reduced p53, p21, and CCND1 expression and increased FOXO3A.

Azithromycin demonstrated anti-aging properties and modulated lung senescence in COPD via the FOXO3A/CCND1 pathway, presenting fresh insights for the treatment of COPD.