Metabolomic analysis to define and compare the effects of PAHs and oxygenated PAHs in developing zebrafish

Abstract

Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives are ubiquitously present in diesel exhaust, atmospheric particulate matter and soils sampled in urban areas. Therefore, inhalation or non-dietary ingestion of both PAHs and oxy-PAHs are major routes of exposure for people; especially young children living in these localities. While there has been extensive research on the parent PAHs, limited studies exist on the biological effects of oxy-PAHs which have been shown to be more soluble and more mobile in the environment. Additionally, investigations comparing the metabolic responses resulting from parent PAHs and oxy-PAHs exposures have not been reported. To address these current gaps, an untargeted metabolomics approach was conducted to examine the in vivo metabolomic profiles of developing zebrafish (Danio rerio) exposed to 4 µM of benz[a]anthracene (BAA) or benz[a]anthracene-7,12-dione (BAQ). By integrating multivariate, univariate and pathway analyses, a total of 63 metabolites were significantly altered after 5 days of exposure. The marked perturbations revealed that both BAA and BAQ affect protein biosynthesis, mitochondrial function, neural development, vascular development and cardiac function. Our previous transcriptomic and genomic data were incorporated in this metabolomics study to provide a more comprehensive view of the relationship between PAH and oxy-PAH exposures on vertebrate development.

Keywords: Exposure; Metabolomics; Oxy-PAHs; PAHs; Zebrafish.

Figure 1

PLS-DA score plot (A) and PCA-DA score plot (B) in the positive ion mode based on the normalized data.

Figure 2

PLS-DA score plot (A) and PCA-DA score plot (B) in negative ion mode based on the normalized data.

Figure 3

Global metabolic disorders of the most relevant pathways influenced by (A) BAA and (B) BAQ treatment

Figure 4

Heat map produced by hierarchical clustering of the most significantly different metabolites obtained from the positive ion mode. The log2 fold change in metabolite levels is color-coded: red pixels denote up regulation; blue pixels denote down regulation. Fold changes were based on peak intensities and relative to a pooled average sample from the control group.