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 62 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.

Effects of 9,10-phenanthrenequione on antioxidant indices and metabolite profiles in Takifugu obscurus plasma

“…As previously reported, treatments with PAHs (benz[a]anthracene and benz[a]anthracene-7,12-dione) exhibited neurobehavioral toxicity to zebrafish (Danio rerio) by affecting the phenylalanine, tyrosine and tryptophan biosynthesis pathway and downregulating dopamine, serotonin, phenylalanine, tyrosine and tryptophan [29]. Similarly, developmental neurotoxicity was observed in Japanese medaka embryos when exposed to benz[a]anthracene [49].…”

“…Among the methods used for metabolomics, liquid chromatography-mass spectrometry (LC-MS) is the most compatible technique for detection of small metabolites and displays robust reliability and reproducibility [27,28]. The LC-MS-based metabolomics has been successfully used to explore effects of two PAHs (benz[a]anthracene and benz[a]anthracene-7,12-dione) on metabolisms of zebrafish, demonstrating toxic influences on protein biosynthesis, mitochondrial function, neural development, vascular development and cardiac function [29]. Thus, metabolomics analyses might be useful to explore influences of oxy-PAHs on fish at the metabolic level.…”

Lethal dysregulation of energy metabolism during embryonic vitamin E deficiency

“…In addition to the IROA database, metabolite identities were confirmed further using the METLIN web-based metabolomics database (http://www.metlin.scripps.edu). Peak intensities for each individual metabolic feature were normalized using the corresponding mean QC sample (n=4) intensity for that feature, as described [26], to balance their differences in intensities that may have arisen due to discrepancies in the sample homogenization (sample preparation). Student’s t -tests (Excel, Microsoft) to compare the two VitE groups at each developmental time-point (24, 48, 72, and 120 hpf) were performed with statistical significance set at p < 0.05.…”

Chronic vitamin E deficiency impairs cognitive function in adult zebrafish via dysregulation of brain lipids and energy metabolism

“…To ensure the stability and repeatability of the LC–MS system, quality control (QC) samples (n=4), which were generated by pooling 10 μL aliquots from each brain extract, were analyzed with the brain samples. Peak intensities for each individual metabolic feature were normalized using the corresponding mean QC sample (n=4) intensity for that feature to balance any differences in intensities that may have arisen during sample preparation, as described [30]. Brain weights were not different between groups; response values for metabolomics were not corrected for brain weights, other samples were corrected as indicated in the figure legends.…”