Effects of chemical composition on the lung cell response to coal particles: Implications for coal workers' pneumoconiosis

Abstract

Background and objective Coal mine dust has a complex and heterogeneous chemical composition. It has been suggested that coal particle chemistry plays a critical role in determining the pathogenesis of coal workers' pneumoconiosis (CWP). In this study, we aimed to establish the association between the detrimental cellular response and the chemical composition of coal particles. Methods We sourced 19 real‐world coal samples. Samples were crushed prior to use to minimize the impact of particle size on the response and to ensure the particles were respirable. Key chemical components and inorganic compounds were quantified in the coal samples. The cytotoxic, inflammatory and pro‐fibrotic responses in epithelial cells, macrophages and fibroblasts were assessed following 24 h of exposure to coal particles. Principal component analysis (PCA) and stepwise regression were used to determine which chemical components of the coal particles were associated with the cell response. Results The cytotoxic, inflammatory and pro‐fibrotic response varied considerably between coal samples. There was a high level of collinearity in the cell responses and between the chemical compounds within the coal samples. PCA identified three factors that explained 75% of the variance in the cell response. Stepwise multiple regression analysis identified K2O (p <0.001) and Fe2O3 (p = 0.011) as significant predictors of cytotoxicity and cytokine production, respectively. Conclusion Our data clearly demonstrate that the detrimental cellular effects of exposure to coal mine dusts are highly dependent on particle chemistry. This has implications for understanding the pathogenesis of CWP.

The effects of coal dust exposure on DNA damage and repair of human bronchial epithelial cells

“…Although the sample of CD obtained by grinding coal was from a specific region, it represents the essential composition of CD. The essential composition of CD samples from different geographic sites is coal particles containing the main elements C, H, N, S, O, and the most abundant inorganic constituents SiO 2 and Al 2 O 3 (Su et al, 2020;Song et al, 2022), which is consistent with our results (Figure 1(b); Table 1). Besides, the CD particles of less than 2 μm (Figure 1(a)) can almost all deposit in the tracheobronchial and alveolar areas, and then produce lung toxicity resulting in difficulty of exhalation.…”

“…Of course, the biological processes induced by CD are complex because of its physical and chemical properties. Both the particle size and elemental composition all have an impact (Zhang et al, 2021; Song et al, 2022), including the genotoxicity and cellular transformation effects we found. Therefore, further research is needed on CD itself and its induced pulmonary toxicity.…”

Transcriptome‐wide association study identifies PSMB9 as a susceptibility gene for coal workers' pneumoconiosis

“…qRT‐PCR results showed significant downregulation of PSMB9 mRNA level in mouse lung tissues at day 7, 14, and 28 after silica exposure in a time‐dependent manner. The pathological process of pneumoconiosis involves multiple cell types, of which epithelial cells and myofibroblasts are the two main types 40,41 . To investigate the role of PSMB9 in CWP in vitro, we treated human epithelial cells (HBE or A549 cells) with standard silica powder and activated human lung fibroblasts (MRC‐5) by using human recombinant TGF‐β1.…”

“…The pathological process of pneumoconiosis involves multiple cell types, of which epithelial cells and myofibroblasts are the two main types. 40,41 To investigate the role of PSMB9 in CWP in vitro, we treated human epithelial cells (HBE or A549 cells) with standard silica powder and activated human lung fibroblasts (MRC-5) by using human recombinant TGF-β1. The PSMB9 mRNA expression level was then measured via qRT-PCR.…”

Characterization and Toxicity Analysis of Lab-Created Respirable Coal Mine Dust from the Appalachians and Rocky Mountains Regions

“…Existing literature has focused on the development of pulmonary fibrosis in pneumoconiosis, largely examining the role of fibroblasts in the development of CWP [76][77][78]. Instead of merely examining the role of fibroblasts, we assessed the impact of coal-based PM10 on epithelial (A549), neutrophilic (HL-60), and macrophage (THP-1) cells.…”