Project description:Chronic early life stress can affect development of the neuroendocrine stress system, leading to its persistent dysregulation and consequently increased disease risk in adulthood. One contributing factor is thought to be epigenetic programming in response to chronic glucocorticoid exposure during early development. We have previously shown that zebrafish embryos treated chronically with cortisol develop into adults with constitutively elevated whole body cortisol and aberrant immune gene expression. The objective of the experiments reported here was to further characterize the phenotype of those adults. We find that adult zebrafish derived from cortisol-treated embryos have aberrant cortisol tissue distribution and dynamics, which correlate with differential transcriptional activity of key glucocorticoid-responsive regulatory genes klf9 and fkbp5 in blood and brain.
Project description:We exposed zebrafish embryos to 0.3, 3, and 30 ppb (µg/L) of ATZ for 72 hours post fertilization. We performed whole-genome bisulfite sequencing (WGBS) to assess the effects of developmental ATZ exposure on DNA methylation in female fish brains
Project description:The zebrafish (Danio rerio) embryo toxicity test (DarT) is considered as an alternative to the acute fish toxicity test. However, DarT rarely reveals information on the mechanisms underlying a toxic effect and is relatively insensitive compared to chronic toxic effects. We hypothesized that, by using gene expression profiles as an additional endpoint, it may be possible to increase the sensitivity and predictive value of DarT. Therefore we exposed zebrafish embryos for 48 h to the reference compound 3,4-dichloroaniline and analyzed gene expression patterns with a 14 k oligonucleotide array. Keywords: differential gene expression upon chemical exposure in zebrafish embryos
Project description:A great number of studies have investigated changes induced by morphine exposure in gene expression using several experimental models. In this study, we examined gene expression changes during chronic exposure to morphine during maturation and differentiation of zebrafish CNS. Our study identified different functional classes of genes and individual candidates involved in the mechanisms underlying susceptibility to morphine actions related to CNS development. These results open new lines to study the treatment of pain and the molecular mechanisms involved in addiction. We also found a set of zebrafish-specific morphine-induced genes, which may be putative targets in human models for addiction and pain processes. Zebrafish embryos were divided into two experimental groups: control embryos and embryos at 5 hpf exposed to 10 nM morphine and collected at 24 hpf (covering the complete embryogenesis). Morphine was administered to the embryos in their water environment, i.e., diluted in E3 embryonic medium. The exposition to begun at the stage of 5 hpf (end of blastula) is continuous, in order to study the chronic effects of the exposure to drug. Microarray experiments were performed using six replicates for each condition, which contained the RNA of approximately one hundred embryos to minimize the influence of potential individual differences between the animals and technical variation introduced by tissue preparation. We previously reported that a concentration of 10 nM morphine is the highest concentration that can be used without a toxic effect on the embryos, and close to 5% of the morphine diluted in the E3 medium is detected in the embryo.