10.6.2022 A multi-omics approach to understand PAH toxicity in rainbow trout (Oncorhynchus mykiss) alevins (Eriksson)

Polycyclic aromatic hydrocarbons (PAHs) are a group of environmental contaminants originating from incomplete combustion or pyrolysis of organic material, as well as intentional or accidental release of crude oil or industrial spillage and effluents. Exposure to PAHs is known to cause toxicity in developing fish larvae, which includes reduced heart rate, increased occurrence of blue sac disease (BSD) symptoms, as well as altered morphology and behavior.
Andreas Eriksson
Published
10.6.2022

The exact mechanisms of PAH-mediated toxicity, in fish larvae, are still not fully understood, even after decades of research. In this doctoral thesis, the toxicity of two PAHs, with different modes of action (retene: an aryl hydrocarbon receptor 2, Ahr2, agonist; and fluoranthene: a weaker Ahr2 agonist and a cytochrome P450a1, Cyp1a, inhibitor), either alone or as a mixture, were investigated in newly hatched rainbow trout (Oncorhynchus mykiss) alevins.

Multiple endpoints, including development and growth, BSD, heart function and PAH accumulation, were investigated in relation to how the cardiac transcriptome, proteome, and metabolome responded. Each treatment resulted a unique toxicity profile, while that the mixture was more potent at inducing toxicity than the components. The transcriptome, proteome and metabolome responded in an exposure specific manner. Alterations in heart function and accumulation of the PAHs were a direct consequence of, and could be explained by, changes in the exposure specific upregulations and enrichments. Additionally, we found a specific metabolite, known as FICZ (an Ahr2 agonist that causes PAH and dioxin-like toxicity), which could contribute to toxicity, accumulated following exposure to the mixture.

Restrictions in energy availability is implied as per numerous enrichments and upregulations, suggesting impaired yolk consumption, which in turn could influence growth and development negatively. These findings, as presented within this doctoral thesis, extend our understanding of how PAH, alone or as a mixture, induces toxicity in developing rainbow trout alevins

The thesis is published in the JYU Dissertations as a number 523, Jyväskylä 2022, ISSN 2489-9003, ISBN 978-951-39-9159-3 (PDF). Link to publication:

M.Sc. Andreas Eriksson defends his doctoral dissertation ”A multi-omics approach to understand PAH toxicity in rainbow trout (Oncorhynchus mykiss) alevins” on 10 June 2022 at 12 noon. Opponent Associate Professor Katja Anttila (University of Turku) and Custos Docent Eeva-Riikka Vehniäinen (Ģֱ). The doctoral dissertation is held in English.