Blocking Expression of AHR2 and ARNT1 in Zebrafish Larvae Protects Against Cardiac Toxicity of 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Antkiewicz, D.S., Peterson, R.E., and Heideman, W.
Toxicological sciences : an official journal of the Society of Toxicology   94(1): 175-182 (Journal)
Registered Authors
Heideman, Warren, Peterson, Richard E.
MeSH Terms
  • Animals
  • Aryl Hydrocarbon Receptor Nuclear Translocator/antagonists & inhibitors
  • Aryl Hydrocarbon Receptor Nuclear Translocator/genetics*
  • Aryl Hydrocarbon Receptor Nuclear Translocator/metabolism
  • Gene Expression Regulation, Developmental/drug effects
  • Gene Expression Regulation, Developmental/genetics
  • Heart Block/chemically induced
  • Heart Block/genetics
  • Heart Block/prevention & control
  • Heart Defects, Congenital/chemically induced
  • Heart Defects, Congenital/genetics
  • Heart Defects, Congenital/prevention & control*
  • Larva/drug effects
  • Larva/genetics
  • Myocytes, Cardiac/drug effects
  • Oligonucleotides, Antisense/administration & dosage
  • Oligonucleotides, Antisense/genetics
  • Protein Isoforms/antagonists & inhibitors
  • Protein Isoforms/genetics
  • Protein Isoforms/metabolism
  • Receptors, Aryl Hydrocarbon/antagonists & inhibitors
  • Receptors, Aryl Hydrocarbon/genetics*
  • Receptors, Aryl Hydrocarbon/metabolism
  • Stroke Volume/drug effects
  • Time Factors
  • Ventricular Function/drug effects
  • Zebrafish/genetics*
  • Zebrafish Proteins/antagonists & inhibitors
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
16936225 Full text @ Toxicol. Sci.
The zebrafish (Danio rerio) has become an attractive vertebrate model for studying developmental processes, and is emerging as a model system for studying the mechanisms by which xenobiotic compounds perturb normal development. Embryos treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) shortly after fertilization exhibit a range of adverse effects on the heart: an early reduction in cardiac myocyte number, followed by a change in heart looping and morphology, with an apparent compaction of the ventricle and overall decrease in heart size. These changes are accompanied by impaired cardiac function including a decrease in cardiac output and eventually irreversible ventricular standstill. The mechanisms involved in mediating effects of TCDD on the heart remain unknown. However, it is widely accepted that aryl hydrocarbon receptor (AHR) activation mediates endpoints of TCDD toxicity in vertebrates. In zebrafish, there are multiple forms of AHR and ARNT raising the question about whether different endpoints of TCDD toxicity are mediated by different components of the AHR/ARNT pathway. To address this question we used morpholino oligonucleotide technology to specifically block the expression of zfAHR2, zfARNT1, zfARNT2, and zfCYP1A, and assessed the previously described effects of TCDD on heart morphology, size and function in the developing morphants. We report that blocking zfAHR2 and zfARNT1 expression provided protection against the TCDD-mediated alteration in heart morphology, reduced cardiac myocyte number, decreased cardiac output and ventricular standstill in zebrafish larvae, while the zfarnt2 and zfcyp1a morpholinos did not block the TCDD-induced cardiac toxicity.
Genes / Markers
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Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes