An integrated systems-level model of ochratoxin A toxicity in the zebrafish (Danio rerio) embryo based on NMR metabolic profiling

Abstract

Ochratoxin A (OTA) is one of the most widespread mycotoxin contaminants of agricultural crops. Despite being associated with a range of adverse health effects, a comprehensive systems-level mechanistic understanding of the toxicity of OTA remains elusive. In the present study, metabolic profiling by high-resolution magic angle spinning (HRMAS) NMR, coupled to intact zebrafish embryos, was employed to identify metabolic pathways in relation to a systems-level model of OTA toxicity. Embryotoxicity was observed at sub-micromolar exposure concentrations of OTA. Localization of OTA, based on intrinsic fluorescence, as well as a co-localization of increased reactive oxygen species production, was observed in the liver kidney, brain and intestine of embryos. Moreover, HRMAS NMR showed significant alteration of metabolites related to targeting of the liver (i.e., hepatotoxicity), and pathways associated with detoxification and oxidative stress, and mitochondrial energy metabolism. Based on metabolic profiles, and complementary assays, an integrated model of OTA toxicity is, thus, proposed. Our model suggests that OTA hepatotoxicity compromises detoxification and antioxidant pathways, leading to mitochondrial membrane dysfunction manifested by crosstalk between pathways of energy metabolism. Interestingly, our data additionally aligns with a possible role of mitochondrial fusion as a “passive mechanism” to rescue mitochondrial integrity during OTA toxicity.

A mechanistic understanding of the effects of polyethylene terephthalate nanoplastics in the zebrafish (Danio rerio) embryo

“…Thus, an increase in ratio of AAA to BCAA in PET NPs treated embryos further indicates that PET NPs causes liver impairment. Furthermore, effect on liver is indicted by an increase in TMAO, which has been proposed in many studies as a potential biomarker of the liver damage 44,46,61 . Targeting of liver by PET NPs would also be consistent with the toxicity observed with PET NPs at later stages of embryo development (Fig.…”

“…Whether PET NPs can affect cellular metabolism is not yet systemically studied. A comprehensive system level tracking of the toxicity pathways affected by PET NPs is necessary to understand the toxicity mechanism of PET NPs.Zebrafish (Danio rerio) is used as a model organism in a wide range of developmental toxicological studies [42][43][44][45][46][47] . Performing developmental toxicity studies using the zebrafish embryo model is advantageous for multiple reasons; (1) to generate a robust sample for downstream applications (transcriptomics, proteomics, and metabolomics) a large number of zebrafish embryos can be exposed in small volumes (e.g., ~ 10 embryos per mL); (2) the pore size of the chorion (0.5-0.7 µm) allows to study a wide range of small molecules 48 ; (3) various developmental stages, from fertilized egg to free-swimming larvae can be studied in short time duration (from 1 h up to few days); (4) a growing range of biochemical and molecular technologies including "omics" approaches have been adapted to zebrafish embryos and larvae [42][43][44][45] .…”

“…Among these, several mass spectrometric (MS) and nuclear magnetic resonance (NMR) spectroscopic tools are available for extracts obtained from zebrafish embryos [49][50][51] . Compared to other techniques high-resolution magic-angle spinning (HRMAS) NMR is a non-destructive technique used to study metabolic profile in intact tissues or organism [43][44][45][46] . In earlier studies, HRMAS NMR has been successfully utilized to investigate alteration of metabolic profiles by various toxicants in early life stages, i.e., embryos and larvae, of the zebrafish [43][44][45][46] .The aim of the present study is to assess the potential toxicity of PET NPs on zebrafish embryos and to get comprehensive system level understanding of the metabolic pathways affected by PET NPs.…”

“…Compared to other techniques high-resolution magic-angle spinning (HRMAS) NMR is a non-destructive technique used to study metabolic profile in intact tissues or organism [43][44][45][46] . In earlier studies, HRMAS NMR has been successfully utilized to investigate alteration of metabolic profiles by various toxicants in early life stages, i.e., embryos and larvae, of the zebrafish [43][44][45][46] .The aim of the present study is to assess the potential toxicity of PET NPs on zebrafish embryos and to get comprehensive system level understanding of the metabolic pathways affected by PET NPs. Although zebrafish embryo has been used previously to investigate the toxicity of PET NPs 39 , the current study is among the first to investigate the toxicity mechanism at whole organism level using non-destructive metabolomics approach of HRMAS NMR.…”

“…Compared to other techniques high-resolution magic-angle spinning (HRMAS) NMR is a non-destructive technique used to study metabolic profile in intact tissues or organism [43][44][45][46] . In earlier studies, HRMAS NMR has been successfully utilized to investigate alteration of metabolic profiles by various toxicants in early life stages, i.e., embryos and larvae, of the zebrafish [43][44][45][46] .…”