Hyphae fragments from A. fumigatus sensitize lung cells to silica particles (Min-U-Sil): Increased release of IL-1β

• Published in: Toxicology in vitro 2019-03, Vol.55, p.1-10
• Main Authors: Øya, E., Zegeye, F.D., Bølling, A.K., Øvstebø, R., Afanou, A.K.J., Øvrevik, J., Refsnes, M., Holme, J.A.
• Format: Article
• Language: English
• Subjects: Acetic acid; Asthma; Caspase; Combined exposure; Cytokines; Epithelial cells; Exposure; Fragments; Gene expression; Hyphae; IL-1β; Inflammation; Interleukin 1; Lipopolysaccharides; Lungs; Macrophages; Mineral particles; Mold/Mold particles; Monocytes; Particulate emissions; Particulate matter; Peripheral blood; Phorbol 12-myristate 13-acetate; Respiratory diseases; Respiratory tract; Silica; Silicon dioxide; Sputum; Synthesis; Transcription; Tumor necrosis factor-TNF; Tumor necrosis factor-α
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2018.11.002

Exposure to particulate matter (PM), such as mineral particles and biological particles/components may be linked to aggravation of respiratory diseases, including asthma. Here we report that exposure to Aspergillus fumigatus hyphae fragments (AFH) and lipopolysaccharide (LPS) induced both mRNA synthesis and release of pro-inflammatory interleukin-1 beta (IL-1β) in both human THP-1 monocytes (THP-1 Mo) and phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 monocytes (THP-1 macrophages; THP-1 Ma); while Min-U-Sil alone enhanced the release of IL-1β only in THP-1 Ma. Co-exposure to LPS or AFH with Min-U-Sil caused a synergistic release of IL-1β when compared to single exposures. In contrast, Min-U-Sil did not markedly change LPS- and AFH-induced release of tumor necrosis factor alpha (TNF-α). The combined exposures did not increase the LPS- and AFH-induced expression of IL-1β mRNA. Notably, the AFH- and LPS-induced IL-1β responses with and without co-exposure to Min-U-Sil in THP-1 Mo were found to be caspase-dependent as shown by inhibition with zYVAD-fmk. Furthermore, co-exposure with AFH and Min-U-Sil resulted in similar synergistic releases of IL-1β in primary human airway macrophages (AM; sputum), peripheral blood monocyte-derived macrophages (MDM) and in the human bronchial epithelial cell line (BEAS-2B). In conclusion, AFH induce both the synthesis and release of IL-1β. However, Min-U-Sil further enhanced the cleavage of the induced pro-IL-1β. •A. fumigatus hyphae induced release of IL-1β in THP-1 monocytes and macrophages•Hyphae and silica synergistically enhanced IL-1β-release in THP-1 cells•Synergistic effect was caspase-dependent•Synergistic effects were also seen in primary human macrophages/lung epithelial cells•Primed cells may represent a relevant model to study particle pollution