PUBLICATION

Soy-Derived Equol Induces Antioxidant Activity in Zebrafish in an Nrf2-Independent Manner

Authors
Watanabe, A., Muraki, K., Tamaoki, J., Kobayashi, M.
ID
ZDB-PUB-220515-15
Date
2022
Source
International Journal of Molecular Sciences   23(9): (Journal)
Registered Authors
Kobayashi, Makoto, Muraki, Kyoji, Tamaoki, Junya, Watanabe, Asami
Keywords
CRISPR-Cas9, Keap1-Nrf2 pathway, antioxidant effect, arsenite, dietary phytochemicals, equol, soy-derived isoflavones, zebrafish
MeSH Terms
  • Animals
  • Antioxidants/metabolism
  • Antioxidants/pharmacology
  • Equol/pharmacology
  • GA-Binding Protein Transcription Factor
  • Isoflavones*/pharmacology
  • Kelch-Like ECH-Associated Protein 1/genetics
  • Kelch-Like ECH-Associated Protein 1/metabolism
  • Larva/metabolism
  • NF-E2-Related Factor 2*/genetics
  • NF-E2-Related Factor 2*/metabolism
  • Zebrafish/genetics
PubMed
35563633 Full text @ Int. J. Mol. Sci.
Abstract
Antioxidant effects of soy-derived isoflavones are predicted to be mediated by the Keap1-Nrf2 pathway. Recently, we constructed an assay system to evaluate the antioxidant effects of dietary phytochemicals in zebrafish and revealed a relationship between these effects and the Keap1-Nrf2 pathway. In this study, we used this system to examine the antioxidant effects of seven isoflavones. Among those seven, equol showed strong antioxidant effects when arsenite was used as an oxidative stressor. The antioxidant effect of equol was also shown in Nrf2-mutant zebrafish nfe2l2afh318, suggesting that this effect was not mediated by the Keap1-Nrf2 pathway. To elucidate this unidentified mechanism, the gene expression profiles of equol-treated larvae were analyzed using RNA-seq and qRT-PCR, while no noticeable changes were detected in the expression of genes related to antioxidant effects, except weak induction of Nrf2 target genes. Because nfe2l2afh318 is an amino acid-substitution mutant (Arg485Lue), we considered that the antioxidant effect of equol in this mutant might be due to residual Nrf2 activity. To examine this possibility, we generated an Nrf2-knockout zebrafish nfe2l2ait321 using CRISPR-Cas9 and analyzed the antioxidant effect of equol. As a result, equol showed strong antioxidant effects even in Nrf2-knockout larvae, suggesting that equol indeed upregulates antioxidant activity in zebrafish in an Nrf2-independent manner.
Genes / Markers
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping