PUBLICATION
Genetic hyperactivation of Nrf2 causes larval lethality in Keap1a and Keap1b-double-knockout zebrafish
- Authors
- Bian, L., Nguyen, V.T., Tamaoki, J., Endo, Y., Dong, G., Sato, A., Kobayashi, M.
- ID
- ZDB-PUB-230320-35
- Date
- 2023
- Source
- Redox Biology 62: 102673102673 (Journal)
- Registered Authors
- Dong, Guilin, Kobayashi, Makoto, Sato, Ayaka, Tamaoki, Junya
- Keywords
- Eating defects, Keap1–Nrf2 pathway, Nrf2-inhibiting compounds, Visual cycle genes, keap1a;keap1b-double knockout zebrafish
- MeSH Terms
-
- Animals
- Animals, Genetically Modified
- Carrier Proteins/metabolism
- Gene Knockout Techniques
- Kelch-Like ECH-Associated Protein 1/genetics
- Kelch-Like ECH-Associated Protein 1/metabolism
- Larva/genetics
- Mammals/metabolism
- NF-E2-Related Factor 2*/genetics
- NF-E2-Related Factor 2*/metabolism
- Oxidative Stress
- Zebrafish*/genetics
- Zebrafish*/metabolism
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
- PubMed
- 36934645 Full text @ Redox Biol.
Citation
Bian, L., Nguyen, V.T., Tamaoki, J., Endo, Y., Dong, G., Sato, A., Kobayashi, M. (2023) Genetic hyperactivation of Nrf2 causes larval lethality in Keap1a and Keap1b-double-knockout zebrafish. Redox Biology. 62:102673102673.
Abstract
The Keap1-Nrf2 pathway is an evolutionarily conserved mechanism that protects cells from oxidative stress and electrophiles. Keap1 is a repressor of Nrf2 in normal cellular conditions but also a stress sensor for Nrf2 activation. Interestingly, fish and amphibians have two Keap1s (Keap1a and Keap1b), of which Keap1b is the ortholog of mammalian Keap1. Keap1a, on the other hand, is a gene found only in fish and amphibians, having been lost during the evolution to amniotes. We have previously shown that keap1b-knockout zebrafish have increased Nrf2 activity and reduced response to certain Nrf2-activating compounds but that they grow normally to adulthood. This may be because the remaining keap1a suppresses the hyperactivation of Nrf2, which is responsible for the post-natal lethality of Keap1-knockout mice. In this study, we analyzed keap1a;keap1b-double-knockout zebrafish to test this hypothesis. We found that keap1a;keap1b-double-knockout zebrafish, like Keap1-knockout mice, showed eating defects and were lethal within a week of hatching. Genetic introduction of the Nrf2 mutation rescued both the eating defects and the larval lethality, indicating that Nrf2 hyperactivation is the cause. However, unlike Keap1-knockout mice, keap1a;keap1b-double-knockout zebrafish showed no physical blockage of the food pathway; moreover, the cause of death was not directly related to eating defects. RNA-sequencing analysis revealed that keap1a;keap1b-double-knockout larvae showed extraordinarily high expression of known Nrf2-target genes as well as decreased expression of visual cycle genes. Finally, trigonelline or brusatol partially rescued the lethality of keap1a;keap1b-double-knockout larvae, suggesting that they can serve as an in vivo evaluation system for Nrf2-inhibiting compounds.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping