Response to low-dose cortisol treatment in zebrafish embryos [larvae]
ABSTRACT: Chronic early life stress increases adult susceptibility to numerous health problems linked to chronic inflammation. One way that this may occur is via glucocorticoid-induced developmental programming. To gain insight into such programming we treated zebrafish embryos with 1 micromolar cortisol and examined the effects on larvae. Treated larvae had elevated whole-body cortisol and glucocorticoid signaling, and up-regulated genes associated with defense response and immune system processes. 6 samples total were analyzed. 3 DMSO controls, and 3 cortisol treated (1 micromolar).
Project description:Chronic early life stress increases adult susceptibility to numerous health problems linked to chronic inflammation. One way that this may occur is via glucocorticoid-induced developmental programming. To gain insight into such programming, we treated zebrafish embryos with cortisol and examined the effects on adults. In adulthood, the treated fish maintained elevated basal cortisol levels in the absence of exogenous cortisol, and constitutively mis-expressed genes involved in defense response and its regulation. Adults derived from cortisol-treated embryos displayed defective tailfin regeneration, heightened basal expression of pro-inflammatory genes, and failure to appropriately regulate those genes following injury or immunological challenge. These results support the hypothesis that chronically elevated glucocorticoid signaling early in life directs development of a pro-inflammatory adult phenotype, at the expense of immunoregulation and somatic regenerative capacity. 30 samples total were analyzed. 9 caudal fins samples (0, 2 and 4dpa), 3 blood samples and 3 muscle samples from adults exposed to DMSO control as embryos. 9 caudal fins samples (0, 2 and 4dpa), 3 blood samples and 3 muscle samples from adults exposed to cortisol (1 micromolar) as embryos.
Project description:Inosine 5'-phosphate dehydrogenase (impdh) has been well known as a key enzyme in GTP biosynthesis pathway. We found that three isoforms of impdh in zebrafish, namely impdh1a, impdh1b and impdh2, all show robust circadian expression.To examine the molecular functions of three impdh isoforms in zebrafish on the genome scale, we measured the global expression changes of impdh1a, impdh1b and impdh2 morpholino injected larvae (morphants) respectively using RNA-seq. Wild type (WT), control and three impdh morphants were collected at 32 hpf. In our RNA-seq result, we identified 468, 331 and 1166 significant genes affected by impdh1a, impdh1b and impdh2 morpholino (MO) knock-down respectively. Among them, there are limited overlaps between genes affected by different MOs and only 36 genes in common among all three MOs. This indicates that the three impdh isoforms have distinct molecular functions. To knock down the target genes, three impdh MOs and control MO were pressure-injected into 1- to 2-cell stage embryos. WT, control and three impdh morphants were raised at 28°C under 14h: 10h light/dark cycle from birth and sampled simultaneously at 32 hpf. Each group has at least 40 embryos.
Project description:ATF6 is a key regulator of the unfolded protein response. Through use of zebrafish and cultured cells we demonstrate that ATF6 drives fatty liver disease by interaction with fatty acid synthase (FASN). Total small RNA from livers of 5 dpf larval zebrafish were collected: 2 batches of Tg(fabp10:nls-mCherry) control larvae, 2 batches of ethanol-treated Tg(fabp10:nls-mCherry) larvae, and 1 batch of Tg(fabp10:nAtf6-cherry; cmlc2:GFP). Each batch was purified for preparation of high-throughput sequencing libraries.
Project description:UHRF1 is an essential regulator of DNA methylation that is highly expressed in many cancers. Using transgenic zebrafish, cultured cells and human tumors, we demonstrate that UHRF1 is an oncogene. RNAseq was used to assess the variation in gene expression between control and experimental samples. Total small RNA from 2 batches of Tg(fabp10:has.UHRF1-GFP)High and age matched Tg(fabp10:nls-mCherry) control 5 dpf zebrafish livers was purified for preparation of high-throughput sequencing libraries.
Project description:Brains are sexually dimorphic in adult zebrafish. We dissected brains from young and old, adult zebrafish, from both males and females. Brains are not pooled but analyzed as indivual samples. Four groups of wild-type zebrafish (AB strain) were used for this study: young (7.5-8.5 months old) male and female and old (31-36 months old) male and female. There were three animals per group for a total of 12 animals in the study.
Project description:The role of microRNAs in gene regulation has been well established. The extent of miRNA regulation also increases with increasing genome complexity. Though the number of genes appear to be equal between human and zebrafish, substantially less microRNAs have been discovered in zebrafish compared to human (Release 19). It appears that most of the miRNAs in zebrafish are yet to be discovered. We sequenced small RNAs from brain, gut, liver, ovary, testis, eye, heart and embryo of zebrafish. In brain, gut and liver sequencing was done in male and female separately. Majority of the sequenced reads (16-62%) mapped to known miRNAs, with the exception of ovary (5.7%) and testis (7.8%). Using the miRNA discovery tool (miRDeep2), we discovered novel miRNAs from the un-annotated reads that ranged from 7.6 to 23.0%, with exceptions of ovary (51.4%) and testis (55.2%). The prediction tool identified a total of 459 novel pre-miRNAs. We compared expression of miRNAs between different tissues and between males and females to identify tissue associated and sex associated miRNAs respectively. These miRNAs could serve as putative biomarkers for these tissues. The brain and liver had highest number of tissue associated (22) and sex associated (34) miRNAs, respectively. This study comprehensively identifies tissue and sex associated miRNAs in zebrafish. Further, we have discovered 459 novel pre-miRNAs (~30% seed homology to human miRNA) as a genomic resource which can facilitate further investigations to understand miRNA-mRNA gene regulatory networks in zebrafish which will have implications in understanding the function of human homologs. Known miRNA profiling, novel miRNA discovery and identification of tissue associated and sex associated miRNAs from sRNA deep sequencing data of different tissues and embryo of zebrafish (in triplicate) was carried out using the Illumina HiSeq 2000 platform.
Project description:The present study provides the first large-scale characterization of miRNAs in M. amblycephala and miRNA profile of M. amblycephala with different growth performance. The discovery of miRNA resource from this study is expected to contribute to a better understanding of the miRNAs roles playing in regulating the growth biological processes in fish and the study of miRNA function and phenotype-associated miRNA identification in fish. To investigate the functions of miRNAs associated with growth of M. amblycephala, we adopted the Solexa sequencing technology to sequence two small RNA libraries prepared from four growth related tissues (brain, pituitary, liver and muscle) of M. amblycephala using individuals with relatively high and low growth rates.
Project description:Glucocorticoids act through the glucocorticoid receptor (GR), a ligand activated transcription factor, to modulate gene expression profiles in target cells and tissues. The principal physiological glucocorticoid in humans, cortisol, is released in a pulsatile fashion from the adrenal gland, which results in oscillations in blood concentrations, with a period of 1 - 2 hours. The biological consequence of fluctuating cortisol concentrations has not been explored. To identify the role of cortisol concentration oscillations for target cell response a flow-through cell culture system was developed. Transcription profiling was performed in the absence and presence of cortisol. Cells were exposed to constant cortisol levels of 100ng/ml or 200 ng/ml or oscillating cortisol concentrations.
Project description:Thousands of large intervening non-coding RNAs (lincRNAs) have been identified in mammals. To better understand the evolution and functions of these enigmatic RNAs, we used chromatin marks, poly(A)-site mapping and RNA-Seq data, to identify more than 550 distinct lincRNAs in zebrafish. Although these shared many characteristics with mammalian lincRNAs, only 29 had detectable sequence similarity with putative mammalian orthologs, typically restricted to a single short region of high conservation. Other lincRNAs had conserved genomic locations without detectable sequence conservation. Antisense reagents targeting conserved regions of two zebrafish lincRNAs caused developmental defects. Reagents targeting splice sites caused the same defects and were rescued by adding either the mature lincRNA or its human or mouse ortholog. Our study provides a roadmap for identification and analysis of lincRNAs in model organisms and shows that lincRNAs play crucial biological roles during embryonic development with functionality conserved despite limited sequence conservation. H3K4me3, H3K36me3 chromatin maps, 3P-Seq and RNA-Seq were used to identify lincRNAs in the zebrafish genome
Project description:The optic vesicle comprises a pool of bi-potential progenitor cells from which the retinal pigment epithelium (RPE) and neural retina fates segregate during ocular morphogenesis. Several transcription factors and signaling pathways have been shown to be important for RPE maintenance and differentiation, but an understanding of the initial fate specification and determination of this ocular cell type is lacking. We show that Yap/Taz-Tead activity is necessary and sufficient for optic vesicle progenitors to adopt RPE identity in zebrafish. A Teadresponsive transgene is expressed within the domain of the optic cup from which RPE arises, and Yap immunoreactivity localizes to the nuclei of prospective RPE cells. yap (yap1) mutants lack a subset of RPE cells and/or exhibit coloboma. Loss of RPE in yap mutants is exacerbated in combination with taz (wwtr1) mutant alleles such that, when Yap and Taz are both absent, optic vesicle progenitor cells completely lose their ability to form RPE. The mechanism of Yap dependent RPE cell type determination is reliant on both nuclear localization of Yap and interaction with a Tead co-factor. In contrast to loss of Yap and Taz, overexpression of either protein within optic vesicle progenitors leads to ectopic pigmentation in a dosagedependent manner. Overall, this study identifies Yap and Taz as key early regulators of RPE genesis and provides a mechanistic framework for understanding the congenital ocular defects of Sveinsson’s chorioretinal atrophy and congenital retinal coloboma. 60 pooled eyes from 36 hpf wild type or vsx2:Gal4/dsRed:14xUAS:YapS87A embryos were pooled for one sample. Three wild type and three vsx2:Gal4/dsRed:14xUAS:YapS87A pools were analyzed for RNA.