Beijing urban particulate matter-induced injury and inflammation in human lung epithelial cells and the protective effects of fucosterol from Sargassum binderi (Sonder ex J. Agardh)

Abstract

Particulate matter (PM) air pollution has gradually become a widespread problem in East Asia. PM may cause unfamiliar inflammatory responses, oxidative stress, and pulmonary tissue damage, and a comprehensive understanding of the underlying mechanisms is required in order to develop effective anti-inflammatory agents. In this study, fine dust collected from Beijing, China (CPM) (size < PM13 with majority < PM2.5) was evaluated for its oxidative stress- and inflammation-inducing effects, which cause cell damage, in A459 human lung epithelial cells. Oxidative stress was marked by an increase in intracellular ROS levels and the production of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and heme oxygenase-1 (HO-1). Upon induction of oxidative stress, a marked increase was observed in the expression of key inflammatory mediators such as COX-2 and PGE2 and the pro-inflammatory cytokines TNF-α and IL-6 via NF-kB and MAPK pathways. Cellular damage was marked by a reduction in viability, increased lactate dehydrogenase (LDH) release, formation of apoptotic and necrotic bodies, accumulation of sub-G1 phase cells, and DNA damage. Apoptosis was found to be mediated via the activation of caspases through the mitochondria-mediated pathway. Fucosterol, purified from the brown alga Sargassum binderi (Sonder ex J. Agardh) by bio-assay-guided fractionation and purification, exhibited potential therapeutic effects against CPM-induced detrimental effects. Further studies could focus on developing fucosterol, in forms such as steroidal inhalers, against PM-induced pulmonary tissue inflammation.