Effects of Components of PM_2.5 Collected in Japan on the Respiratory and Immune Systems

Abstract

Epidemiologic studies have reported that particulate matter with aerodynamic diameters ≤2.5 μm (PM) affect respiratory diseases, including asthma. The components and/or factors of PM that contribute to the exacerbation of asthma have not been identified. We investigated the effects of extracts of PM collected in Japan on the respiratory and immune systems. PM was collected from an industrial area and an urban area in December 2013. Airway epithelial cells and immune cells were exposed to aqueous or organic extracts of PM. Exposure to extracts from both areas, especially to organic extracts rather than aqueous extracts, caused a pro-inflammatory response via interleukin (IL) 6 production from airway epithelial cells, and it induced the maturation/activation of bone marrow-derived antigen-presenting cells via dendritic and epithelial cell (DEC) 205 and cluster of differentiation (CD) 86 expression and proportional changes in the constitution of the splenocytes. The extracts collected from the industrial area tended to show greater effects than those from the urban area. These results suggest that organic components of PM affect the respiratory and immune systems. These effects can differ by the collection areas. In addition, IL-6, DEC205, and CD86 can be predictive biomarkers for the respiratory and immune effects of ambient PM.

Aqueous and organic extract of PM2.5 collected in different seasons and cities of Japan differently affect respiratory and immune systems

“…IL-6 and IL-8 are the two most prominent pro-inflammation mediators (Martin et al 1997;Richman-Eisenstat et al 1993). Our previous study (Honda et al 2017) based on Kawasaki and Fukuoka have shown that organic extracts had more pro-inflammatory effect via IL-6 than aqueous extracts. As the IL-6 and IL-8 expression did not increase at all in the present study, we did not observe any noticeable pro-inflammatory effect by any extract.…”

“…CD86 is an important and sensitive cell surface molecule for PAHs, as we recently have observed (Chowdhury et al 2017). Moreover, our previous studies revealed aqueous extract from Kawasaki and Fukuoka were able to increase the CD86 expression on the cells (Honda et al, 2017). Hulette et al, 2005 showed that aqueous soluble chemicals including nickel sulphate and hydroquinone are capable to induce CD86 expression in human dendritic cells.…”

“…DEC205 is an important cell surface molecule for antigen uptake, processing, and presentation of the antigen by dendritic cells (Tel et al 2011). Previous investigations indicated that environmental pollutants including PM2.5 extract, carbon black nanoparticles, Asian sand dust particles, and di-(2-ethylhexyl) phthalate can promote the maturation/activation and function of DEC205 on APCs (Honda et al 2017;Koike et al 2008Koike et al , 2009Honda et al 2014). From our experimental results, it can be concluded that aqueous PM2.5 extracts from Fukuoka induce the maturation/activation of DEC205.…”

“…It is known internationally for its global industrial enterprises. Honda et al (2017) demonstrated that a PM2.5 extract from Kawasaki had a pro-inflammatory effect on airway cells and activated immune cells, causing respiratory allergy.…”

Viruses and non-allergen environmental triggers in asthma

“…120 121 It has also been shown that differences in DEP (a heterogeneous product with regional component variability) have differing effects on IL-6, with organic components having a predominantly stimulatory effect and non-organic components inhibiting IL-6 production. 87 IL-4 and IL-8 also increase in patients with asthma with DEP exposure, with the former showing particular elevation during acute exacerbations. 122 123 In addition to stimulating T2-high inflammation, DEP also appears to independently suppress common mediators of T2-low inflammation.…”