Retinoic acid (RA) and 2,3,7,8-tetrachlorodibenzo-p-dioxin activate distinct ligand-dependent transcription factors, and both cause cardiac malformation and heart failure in zebrafish embryos. We hypothesized that they cause this response by hyperactivating a common set of genes critical for heart development. To test this, we used microarrays to measure transcripts changes in hearts isolated from zebrafish embryos 1,2,4 and 12 h after exposure to 1M RA. We used hierarchical clustering to compare the transcriptional responses produced in the embryonic heart by RA and TCDD. We could identify no early responses in common between the two agents. However, at 12 h both treatments produced a dramatic downregulation of a common cluster of cell cycle progression genes, which we term the Cell Cycle Gene Cluster (CCGC). This was associated with a halt in heart growth. These results suggest that RA and TCDD ultimately trigger a common transcriptional response associated with heart failure, but not through the direct activation of a common set of genes. Among the genes rapidly induced by RA was Nr2F5, a member of the COUP-TF family of transcription repressors. We found that induction of Nr2F5 was both necessary and sufficient for the cardiotoxic response to RA.
Comparative genomics identifies genes mediating cardiotoxicity in the embryonic zebrafish heart.
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View SamplesThe purpose of this experiment is to understand which transcripts are differentially expressed following exposure to TCDD.
TCDD inhibits heart regeneration in adult zebrafish.
Treatment
View SamplesMitochondria are centers of metabolism and signaling whose content and function must adapt to changing cellular environments. The biological signals that initiate mitochondrial restructuring and the cellular processes that drive this adaptive response are largely obscure. To better define these systems, we performed matched quantitative genomic and proteomic analyses of mouse muscle cells as they performed mitochondrial biogenesis. We find that proteins involved in cellular iron homeostasis are highly coordinated with this process, and that depletion of cellular iron results in a rapid, dose-dependent decrease of select mitochondrial protein levels and oxidative capacity. We further show that this process is universal across a broad range of cell types and fully reversed when iron is reintroduced. Collectively, our work reveals that cellular iron is a key regulator of mitochondrial biogenesis, and provides quantitative datasets that can be leveraged to explore post-transcriptional and post-translational processes that are essential for mitochondrial adaptation.
Complementary RNA and protein profiling identifies iron as a key regulator of mitochondrial biogenesis.
Cell line, Treatment
View SamplesTo help elucidate the metabolic changes in the skin that contribute to the obesity resistance and skin pathology in mice lacking Scd1, we performed microarray analysis of skin gene expression in male skin Scd1 knockout (SKO) and Scd1 flox/flox control (Lox) mice fed a standard rodent diet.
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Sex, Specimen part
View SamplesExposure to environmental contaminants can disrupt normal development of the early vertebrate skeleton. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) impairs craniofacial skeletal development across many vertebrate species and its effects are especially prominent in early life stages of fish. TCDD activates the aryl hydrocarbon receptor (AHR), a transcription factor that mediates most if not all TCDD responses. We investigated the transcriptional response in the developing zebrafish jaw following TCDD exposure using DNA microarrays. Zebrafish larvae were exposed to TCDD at 96 h postfertilization (hpf) and jaw cartilage tissue was harvested for microarray analysis at 1, 2, 4 and 12 h postexposure (hpe). Numerous chondrogenic transcripts were misregulated by TCDD in the jaw. Comparison of transcripts altered by TCDD in jaw with transcripts altered in embryonic heart showed that the transcriptional responses in the jaw and the heart were strikingly different. Sox9b, a critical chondrogenic transcription factor, was the most significantly reduced transcript in the jaw. We hypothesized that the TCDD reduction of sox9b expression plays an integral role in affecting formation of the embryonic jaw. Morpholino knock down of sox9b expression demonstrated that partial reduction of sox9b expression alone was sufficient to produce a TCDD-like jaw phenotype. Heterozygous sox9b deletion mutant embryos were sensitized to TCDD. Lastly, embryos injected with sox9b mRNA and then exposed to TCDD blocked TCDD-induced jaw toxicity in approximately 14% of sox9b-injected embryos. These results suggest that reduced sox9b expression in TCDD-exposed zebrafish embryos contributes to jaw malformation. Experiment Overall Design: Three independent replicate microarray time course experiments were performed comparing transcript levels between TCDD-exposed and control zebrafish. For each experiment, zebrafish were exposed to TCDD for 1 h starting at 96 hpf as described above. For each time point (97, 98, 100 and 108 hpf) and treatment jaw samples were pooled from 10 dissections for RNA isolation and hybridization with Affymetrix zebrafish arrays (Affymetrix, Santa Clara, CA). Each microarray contains roughly 14,900 probes corresponding to approximately 30% of the zebrafish genome. For each array, total RNA (1 µg) was isolated from 10 jaw microdissections with the QIAGEN RNeasy Mini kit following the manufacturer’s protocol (QIAGEN, Valencia, CA). The One-Cycle Target Labeling and Control Reagents kit was used to synthesize cDNA and biotinylated cRNA following the manufacturer’s protocol (Affymetrix, Santa Clara, CA). Biotin-labeled cRNA (15 µg) was fragmented and hybridized onto Affymetrix Zebrafish Genechip Arrays following the protocol in the Affymetrix Genechip Expression Analysis Technical Manual. Following hybdrization, the arrays were washed and stained with streptavidin-phycoerythrin on an Affymetrix Fluidics Station 400 using the protocol EukGE WS2v4. Arrays were scanned with an Agilent Gene Array Scanner.
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Subject
View SamplesProtein and mRNA levels for several selenoproteins, such as glutathione peroxidase-1 (Gpx1), are down-regulated dramatically by selenium (Se) deficiency.
No associated publication
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The cohesin-associated protein Wapal is required for proper Polycomb-mediated gene silencing.
Specimen part
View SamplesWe investigated in mouse models how enhanced coagulation activation due to a common disease polymorphism in coagulation factor V (fV Leiden Arg506Gln) modifies the host response to infection and inflammation
No associated publication
No sample metadata fields
View SamplesThe cohesin offloading protein Wapal also acts as a polycomb factor in flies. We examined its role in transcriptional role in murine embryonic stem cells (ESCs)
The cohesin-associated protein Wapal is required for proper Polycomb-mediated gene silencing.
Specimen part
View SamplesThe relative contribution of induced and natural Foxp3+ regulatory T cells (iTreg and nTreg cells, respectively) to the maintenance of tolerance is unknown. We examined their respective roles by in vivo adoptive transfer immunotherapy of newborn Foxp3-deficient BALB/c mice. Survival, weight gain, tissue infiltration, T cell activation, and the concentration of proinflammatory cytokines were used as outcome measurements. Treatment with iTreg cells alone was not successful. While effective in preventing death, treatment with nTreg cells alone was associated with chronic inflammation and autoimmunity. Outcomes markedly improved when conventional T (Tconv) cells were transferred together with the nTreg cells, where 10% of the peripheral Treg cell pool was derived by in-situ conversion. This enhancement depended upon the capacity of Tconv cells to express Foxp3.
A requisite role for induced regulatory T cells in tolerance based on expanding antigen receptor diversity.
Age, Specimen part
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