Early life exposure to low levels of AHR agonist PCB126 (3,3',4,4',5-pentachlorobiphenyl) reprograms gene expression in adult brain

Aluru, N., Karchner, S.I., Glazer, L.
Toxicological sciences : an official journal of the Society of Toxicology   160(2): 386-397 (Journal)
Registered Authors
Karchner, Sibel
DOHaD, RNAseq, brain, latent effects, males, zebrafish
MeSH Terms
  • Age Factors
  • Animals
  • Aryl Hydrocarbon Hydroxylases/genetics
  • Aryl Hydrocarbon Hydroxylases/metabolism
  • Behavior, Animal/drug effects
  • Brain/drug effects*
  • Brain/growth & development
  • Brain/metabolism
  • Cellular Reprogramming/drug effects*
  • Embryo, Nonmammalian/drug effects
  • Embryo, Nonmammalian/metabolism
  • Environmental Pollutants/toxicity*
  • Gene Expression Regulation
  • Gene Regulatory Networks
  • Polychlorinated Biphenyls/toxicity*
  • Receptors, Aryl Hydrocarbon/agonists*
  • Receptors, Aryl Hydrocarbon/genetics
  • Receptors, Aryl Hydrocarbon/metabolism
  • Time Factors
  • Transcriptome
  • Zebrafish/embryology
  • Zebrafish Proteins/agonists*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism
28973690 Full text @ Toxicol. Sci.
Early life exposure to environmental chemicals can have long-term consequences that are not always apparent until later in life. We recently demonstrated that developmental exposure of zebrafish to low, non-embryotoxic levels of 3,3',4,4',5-pentachlorobiphenyl (PCB126) did not affect larval behavior, but caused changes in adult behavior. The objective of this study was to investigate the underlying molecular basis for adult behavioral phenotypes resulting from early life exposure to PCB126. We exposed zebrafish embryos to PCB126 during early development and measured transcriptional profiles in whole embryos, larvae and adult male brains using RNA-sequencing. Early life exposure to 0.3 nM PCB126 induced cyp1a transcript levels in 2-dpf embryos, but not in 5-dpf larvae, suggesting transient activation of aryl hydrocarbon receptor with this treatment. No significant induction of cyp1a was observed in the brains of adults exposed as embryos to PCB126. However, a total of 2209 and 1628 genes were differentially expressed in 0.3 nM and 1.2 nM PCB126-exposed groups, respectively. KEGG pathway analyses of upregulated genes in the brain suggest enrichment of calcium signaling, MAPK and notch signaling, and lysine degradation pathways. Calcium is an important signaling molecule in the brain and altered calcium homeostasis could affect neurobehavior. The downregulated genes in the brain were enriched with oxidative phosphorylation and various metabolic pathways, suggesting that the metabolic capacity of the brain is impaired. Overall, our results suggest that PCB exposure during sensitive periods of early development alters normal development of the brain by reprogramming gene expression patterns, which may result in alterations in adult behavior.
Genes / Markers
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes