TitleMechanistic Investigations Into the Developmental Toxicity of Nitrated and Heterocyclic PAHs.
Publication TypeJournal Article
Year of Publication2017
AuthorsChlebowski, AC, Garcia, GR, La Du, JK, Bisson, WH, Truong, L, Simonich, SLMassey, Tanguay, RL
JournalToxicol Sci
Date Published2017 05 01
KeywordsAnimals, Animals, Genetically Modified, Cytochrome P-450 CYP1A1, Gene Knockdown Techniques, Heterocyclic Compounds, Hydrocarbons, Cyclic, Nitrates, Oxidative Stress, Receptors, Aryl Hydrocarbon, Stress, Physiological, Teratogens, Zebrafish

Nitrated polycyclic aromatic hydrocarbons (NPAHs) and heterocyclic PAHs (HPAHs) are recognized environmental pollutants. However, the health risks of NPAHs and HPAHs to humans and environmental systems are not well-studied. The developmental zebrafish (Danio rerio) model was used to evaluate the toxicity of a structurally diverse set of 27 NPAHs and 10 HPAHs. The individual activity of each compound towards the aryl hydrocarbon receptor (AHR), including the role of the AHR in observed toxicity, and genetic markers of oxidative stress and cardiac toxicity were evaluated. Zebrafish embryos were exposed from 6 to 120 hours post fertilization (hpf), to a broad concentration range of individual compounds, and evaluated for 22 developmental endpoints. The potential role of AHR was determined using the transgenic Tg(cyp1a:nls-egfp) reporter zebrafish line. All compounds were screened computationally through molecular docking using a previously developed AHR models of zebrafish isoforms 1A, 1B, and 2. Some compounds did not induce observable developmental toxic responses, whereas others produced statistically significant concentration-dependent toxicity. The tested compounds also exhibited a range of predicted AHR binding and cyp1a/GFP induction patterns, including cyp1a expression in the liver, vasculature, skin, and yolk, which we determined to be due to distinct isoforms of the AHR, using morpholino oligonucleotide knockdown. Furthermore, we investigated mRNA expression of oxidative and cardiac stress genes at 48 and 120 hpf, which indicated several potential mechanisms-of-action for NPAHs. Overall, we observed a range of developmental toxicities, cyp1a/GFP expression patterns, and gene expression profiles, suggestive of several potential mechanisms of action.

Alternate JournalToxicol. Sci.
PubMed ID28186253
PubMed Central IDPMC5414855
Grant ListF31 ES026037 / ES / NIEHS NIH HHS / United States
T32 ES007060 / ES / NIEHS NIH HHS / United States