Metabolic responses to in-vitro biomass burning aerosol exposure in liver disease model
2Department of Earth and Planetary Sciences, Weizmann Institute of Science, Israel
3Liver Disease Center, Sheba Medical Center, Israel
4Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, USA
Background:
Biomass burning (BB) is a significant and increasing source of atmospheric particles and gases with potential delirious effects on health, including liver disease. Wood tar (WT) aerosols, emitted during the pyrolysis stage in smoldering burning, is a major constituent of BB aerosols. However, the underlying toxicology linking WT to adverse hepatic phenotypes is undefined. Untargeted metabolomics offers a data-driven approach to identify altered metabolism linking WT exposure and liver disease.
Methods:
WT was generated by the pyrolysis of pine wood pallets and the water-soluble fraction used for exposure. The human liver epithelial HepG2, stellate LX2, and lung epithelia A549 cell lines were used (n=5). The cells were exposed to water-soluble WT extracts at 0.02 g/L (low exposure) or 0.2 g/L (high exposure). A blank extract with water instead of WT underwent the same procedures (control). After 5 h of exposure, cells were extracted with 80% methanol solution. The metabolite-containing supernatants were analyzed with HILIC liquid-chromatography high-resolution mass spectrometry (LC-HRMS, IQX Thermo Scientific).
Metabolite data was extracted and annotated using Compound Discoverer (Thermo Scientific). Metabolites with a median intensity fold change ≥ 2 or ≤ 0.5 between high exposure and control cells were exported for statistical analysis. Metabolites were DESeq2 normalized and visualized. Differential metabolite analysis was performed using the pair-wised Wald test, with a FDR adjusted p-value < 0.05.
Results:
Following WT exposure, intensities for 176 metabolites in HepG2 cells, 164 metabolites in LX2 cells, and 145 metabolites in A549 cells were significantly different.
Discussion and Conclusions:
Several metabolites were associated with WT exposure, including glutathione and hypoxanthine. These metabolites suggest a role of purine metabolism and oxidative stress in BB-related liver toxicity.
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