Assessment of parental beno[a]pyrene exposure-induced cross-generational neurotoxicity and changes in offspring sperm DNA methylome in medaka fish




WAN, Teng, Miles
AU, Wai Ting Doris
MO, Jiezhang
Chen, Lianguo
Cheung, Kwok-Ming
KONG, Yuen Chong Richard
Seemann, Frauke

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Previous studies have revealed that DNA methylation changes could serve as potential genomic markers for environmental benzo[a]pyrene (BaP) exposure and intergenerational inheritance of various physiological impairments (e.g. obesity and reproductive pathologies). As a typical aromatic hydrocarbon pollutant, direct BaP exposure has been shown to induce neurotoxicity. To unravel the inheritance mechanisms of the BaP-induced bone phenotype in freshwater medaka, we conducted whole-genome bisulfte sequencing of F1 sperm and identifed 776 differentially methylated genes (DMGs). Ingenuity pathway analysis revealed that DMGs were signif cantly enriched in pathways associated with neuronal development and function. Therefore, it was hypothesized that parental BaP exposure (1 μg/l, 21 days) causes offspring neurotoxicity. Furthermore, the possibility for sperm methylation as an indicator for a neu rotoxic phenotype was investigated. The F0 adult brains and F1 larvae were analyzed for BaP-induced direct and inherited toxicity. Acetylcholinesterase activity was signifcantly reduced in the larvae, together with decreased swimming velocity. Molecular analysis revealed that the marker genes associated with neuron development and growth (alpha1-tubulin, mbp, syn2a, shh, and gap43) as well as brain development (dlx2, otx2, and krox-20) were universally downregulated in the F1 larvae (3 days post-hatching). While parental BaP exposure at an environmentally relevant concentration could induce neurotoxicity in the developing larvae, the brain function of the exposed F0 adults was unaffected. This indicates that developmental neurotoxicity in larvae may result from impaired neuronal devel opment and differentiation, causing delayed brain growth. The present study demonstrates that the possible adverse health effects of BaP in the environment are more extensive than currently understood. Thus, the possibility of multigenerational BaP toxicity should be included in environmental risk assessments.



benzo[a]pyrene, neurotoxicity, locomotion, central nervous system, brain development, dna methylation


This work was supported by funding from the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (SMSEGL20SC02) and the National Natural Science Foundation of China (No. 41977371). Dr F.S. was supported by the National Institute of Environmental Health Sciences of the National Institutes of Health under award number 1R15ES032936-01.


Attribution-NonCommercial 4.0 International


Teng Wan, Doris Wai-Ting Au, Jiezhang Mo, Lianguo Chen, Kwok-Ming Cheung, Richard Yuen-Chong Kong, Frauke Seemann, Assessment of parental benzo[a]pyrene exposure-induced cross-generational neurotoxicity and changes in offspring sperm DNA methylome in medaka fish, Environmental Epigenetics, Volume 8, Issue 1, 2022, dvac013,