ABSTRACT: Comparative analysis of the transcriptome responses of zebrafish embryos after exposure to low concentrations of essential and non-essential metals.
Project description:Metal toxicity is a global environmental challenge. Fish are particularly prone to metal exposure, which can be lethal or can cause sublethal physiological impairments. The objective of this study was to improve our understanding on how adverse effects of essential and non-essential metals in early life stage zebrafish may be explained by changes in the transcriptome after exposure to non-toxic levels. We therefore studied the effects of three different metals at low concentrations in zebrafish embryos by transcriptomics analysis. The study design compared exposure effects caused by different metals at different developmental stages (pre-hatch and post-hatch). Wild-type embryos were exposed to solutions of low concentrations of copper (CuSO4), cadmium (CdCl2) and cobalt (CoSO4) until 96 h post-fertilization (hpf) and microarray experiments were carried out to determine transcriptome profiles at 48 and 96 hpf. We found that the toxic metal cadmium affected the expression of more genes at 96 hpf than 48 hpf. The opposite effect was observed for the essential metals cobalt and copper, which also showed enrichment of different GO terms. Genes involved in neuromast and motor neuron development, were significantly enriched, agreeing with our previous results showing motor neuron and neuromast damage in the embryos. Our data provide evidence that the response of the transcriptome of fish embryos to metal exposure differs for essential and non-essential metals.
Project description:To identify molecular effects of the antineoplastic agent PKC412 (Midostaurin), we applied gene expression profiling in zebrafish using whole genome microarrays. Zebrafish eleuthero-embryos were exposed for 6 dpf to nominal levels of 2 μg/L and 40 μg/L PKC412. Among the 259 and 511 altered transcripts at both concentrations, respectively, the expressions of genes involved in the circadian rhythm were of interest. Alteration of swimming behaviour was not noted. Pathways of interest affected by PKC412 were angiogenesis, apoptosis, DNA damage response and response to oxidative stress. Angiogenesis was not altered by PKC412 treatment at both concentrations. Apoptosis occurred in olfactory placodes of embryos exposed to 40 μg/L, and DNA damage was induced at both PKC412 concentrations. However, there were no significant effects on reactive oxygen species formation. This study leads to the conclusion that PKC412-induced alterations of gene transcripts are partly paralleled by physiological effects at high, but not at low PKC412 concentrations expected to be of environmental relevance. Gene expression in zebrafish eleuthero-embryos was measured after exposure for 6dpf to 2 ug/L and 40 ug/L PKC412 or to the respective controls. A total of 12 arrays (Agilent 4 × 44 K Zebrafish microarray) were used, including four for the water control group, four for the solvent control group, four for the 2 μg/L and four for the 40 μg/L PKC412 dose group.
Project description:We applied zebrafish whole genome microarrays to identify molecular effects of diazepam, a neuropharmaceutical encountered in wastewater-contaminated environments, and to elucidate its neurotoxic mode of action. Behavioral studies were performed to analyze for correlations between altered gene expression with effects on the organism level. Male zebrafish and zebrafish eleuthero-embryos were exposed for 14 d or up to 3 d after hatching, respectively, to nominal levels of 273 ng/L and 273 μg/L (determined water concentrations in the adult experiment 235 ng/L and 291 μg/L). Among the 51 and 103 altered transcripts at both concentrations, respectively, the expression of genes involved in the circadian rhythm in adult zebrafish and eleuthero-embryos were of particular significance, as revealed both by microarrays and quantitative PCR. The swimming behavior of eleuthero-embryos was significantly altered at 273 μg/L. The study leads to the conclusion that diazepam-induced alterations of genes involved in circadian rhythm are paralleled by effects in neurobehavior at high, but not at low diazepam concentrations that may occur in polluted environments. Gene expression in male zebrafish brain was measured after exposure for 14 d to 273 ng/L and 273 ug/L diazepam or to the water control. A total of 11 arrays (Agilent 4 × 44 K Zebrafish microarray) were used, including three for the water control group, four for the 273 ng/L and four for the 273 μg/L diazepam dose group.
Project description:We applied zebrafish whole genome microarrays to identify molecular effects of diazepam, a neuropharmaceutical encountered in wastewater-contaminated environments, and to elucidate its neurotoxic mode of action. Behavioral studies were performed to analyze for correlations between altered gene expression with effects on the organism level. Male zebrafish and zebrafish eleuthero-embryos were exposed for 14 d or up to 3 d after hatching, respectively, to nominal levels of 273 ng/L and 273 μg/L (determined water concentrations in the adult experiment 235 ng/L and 291 μg/L). Among the 51 and 103 altered transcripts at both concentrations, respectively, the expression of genes involved in the circadian rhythm in adult zebrafish and eleuthero-embryos were of particular significance, as revealed both by microarrays and quantitative PCR. The swimming behavior of eleuthero-embryos was significantly altered at 273 μg/L. The study leads to the conclusion that diazepam-induced alterations of genes involved in circadian rhythm are paralleled by effects in neurobehavior at high, but not at low diazepam concentrations that may occur in polluted environments.
Project description:To identify molecular effects of the antineoplastic agent PKC412 (Midostaurin), we applied gene expression profiling in zebrafish using whole genome microarrays. Zebrafish eleuthero-embryos were exposed for 6 dpf to nominal levels of 2 μg/L and 40 μg/L PKC412. Among the 259 and 511 altered transcripts at both concentrations, respectively, the expressions of genes involved in the circadian rhythm were of interest. Alteration of swimming behaviour was not noted. Pathways of interest affected by PKC412 were angiogenesis, apoptosis, DNA damage response and response to oxidative stress. Angiogenesis was not altered by PKC412 treatment at both concentrations. Apoptosis occurred in olfactory placodes of embryos exposed to 40 μg/L, and DNA damage was induced at both PKC412 concentrations. However, there were no significant effects on reactive oxygen species formation. This study leads to the conclusion that PKC412-induced alterations of gene transcripts are partly paralleled by physiological effects at high, but not at low PKC412 concentrations expected to be of environmental relevance.
Project description:Methyl tert-butyl ether (MTBE) has been shown to target developing vasculature in piscine and mammalian model systems. In the zebrafish, MTBE induces vascular lesions throughout development. These lesions result from exposure to MTBE at an early stage in development (6-somites to Prim-5 stages). During this time period, transcript levels of vegfa, vegfc, and vegfr1 were significantly decreased in embryos exposed to 5 mM MTBE. We performed global gene analysis as an unbiased approach to discover possible modes of action of MTBE vascular toxicity. Embryos were exposed at 3 hours post fertilization (hpf) in triplicate to one of three concentrations of MTBE: 5mM (induces vascular lesions and significantly decreases vegfa), 0.625mM (NOAEL; no observed adverse effect level), and 0.00625mM (100-fold below NOAEL), or to embryo media (control). Samples were collected at 6-somites (~15hpf), 21-somites (~24 hpf), and Prim-5 (~30 hpf) stages of development. Embryos were meticulously staged at exposure and at the time of collection to maintain a homogeneous population. Our experimental design sought to explore the effect of three concentrations MTBE on three different stages of zebrafish embryonic development during the critical period established for the chemical. This time period also corresponds to an important time in the cardiovascular system develop of our model vertebrate.