PM_2.5 induces lung inflammation through ANGPTL4

Fine particulate matter (PM_2.5) is a common major air pollutant associated with decreased lung function, induced allergic airway inflammation closely correlated with chronic lung diseases. Angiopoietin-like protein 4 (ANGPTL4) is a cytokine with multiple functions, participating in processes such as inflammation, angiogenesis, and metastasis. Curcumin is an active compound found in turmeric plants and possesses various pharmacological effects, including antioxidant, anti-inflammatory, anticancer, and immunomodulatory properties. The aim of this study was twofold: firstly, to investigate the involvement of ANGPTL4 in lung inflammation and carcinogenesis under PM_2.5 exposure, and secondly, to explore the impact of curcumin on ANGPTL4 expression and its potential in lung cancer chemoprevention. We used protein array to detect several proinflammatory cytokines and then used qPCR to confirm by increasing the concentration of PM_2.5 to enhance the expressions of CXCL1, CXCL5; IL-1α, IL-1β, MIP-3α and inflammation- or fibrosis-associated proteins. Curcumin inhibits PM_2.5-induced ANGPTL4 and the IκB-α (inhibitor of NFκB)-dependent inflammatory pathway. Silencing ANGPTL4 by shRNA restore IκB-α and MIP-3α expression. In conclusion, the increased expression of ANGPTL4 after treatment with PM_2.5 in lung cells may be one of the mechanisms by which PM_2.5 exposure contributes to lung inflammation progression. Our results provide evidence that curcumin in anti-inflammation therapeutics could serve as a beneficial chemopreventive agent.