PUBLICATION
Identification of molecular toxicity pathways across early life-stages of zebrafish exposed to PCB126 using a whole transcriptomics approach
- Authors
- Meyer-Alert, H., Wiseman, S., Tang, S., Hecker, M., Hollert, H.
- ID
- ZDB-PUB-210106-19
- Date
- 2021
- Source
- Ecotoxicology and environmental safety 208: 111716 (Journal)
- Registered Authors
- Keywords
- AHR, Development, Embryo, Eye, Mode of action
- MeSH Terms
-
- Animals
- Embryo, Nonmammalian/drug effects
- Embryonic Development/drug effects*
- Embryonic Development/genetics
- Gene Expression Regulation, Developmental/drug effects
- Polychlorinated Biphenyls/toxicity*
- Receptors, Aryl Hydrocarbon/antagonists & inhibitors
- Teratogens/toxicity*
- Transcriptome
- Water Pollutants, Chemical/toxicity*
- Zebrafish/embryology*
- Zebrafish/genetics
- Zebrafish/metabolism
- Zebrafish Proteins/antagonists & inhibitors
- PubMed
- 33396047 Full text @ Ecotoxicol. Environ. Saf.
Citation
Meyer-Alert, H., Wiseman, S., Tang, S., Hecker, M., Hollert, H. (2021) Identification of molecular toxicity pathways across early life-stages of zebrafish exposed to PCB126 using a whole transcriptomics approach. Ecotoxicology and environmental safety. 208:111716.
Abstract
Although withdrawn from the market in the 1980s, polychlorinated biphenyls (PCBs) are still found ubiquitously in the aquatic environment and pose a serious risk to biota due to their teratogenic potential. In fish, early life-stages are often considered most sensitive with regard to their exposure to PCBs and other dioxin-like compounds. However, little is known about the molecular drivers of the frequently observed teratogenic effects. Therefore, the aims of our study were to: (1) characterize the baseline transcriptome profiles at different embryonic life-stages in zebrafish (Danio rerio); and (2) to identify the molecular response to PCB exposure and life-stage specific-effects of the chemical on associated processes. For both objectives, embryos were sampled at 12, 48, and 96 h post-fertilization (hpf) and subjected to Illumina sequence-by-synthesis and RNAseq analysis. Results revealed that with increasing age more genes and related pathways were upregulated both in terms of number and magnitude. Yet, other transcripts followed an opposite pattern with greater transcript abundance at the earlier time points. Additionally, embryos were exposed to PCB126, a potent agonist of the aryl hydrocarbon receptor (AHR). ClueGO network analysis revealed significant enrichment of genes associated with basic cell metabolism, communication, and homeostasis as well as eye development, muscle formation, and skeletal formation. We selected eight genes involved in the affected pathways for an in-depth characterization of their regulation throughout normal embryogenesis and after exposure to PCB126 by quantification of transcript abundances every 12 h until 118 hpf. Among these, fgf7 and c9 stood out because of their strong upregulation by PCB126 exposure at 48 and 96 hpf, respectively. Cyp2aa12 was upregulated from 84 hpf on. Fabp10ab, myhz1.1, col8a1a, sulf1, and opn1sw1 displayed specific regulation depending on the developmental stage. Overall, we demonstrate that (1) the developmental transcriptome of zebrafish is highly dynamic, and (2) dysregulation of gene expression by exposure to PCB126 was significant and in several cases not directly connected to AHR-signaling. Hence, this study improves the understanding of linkages between molecular events and apical outcomes that are of regulatory relevance.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping