Exposure 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.
Aryl hydrocarbon receptor-mediated down-regulation of sox9b causes jaw malformation in zebrafish embryos.
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View SamplesRetinal detachment is a major cause of blindness due to penetrating trauma and ocular inflammation, and is often observed in many patients following cataract extraction surgery. When the retinal photoreceptors detach from their epithelium, stress signals and apoptotic pathways are initiated that will lead to loss of vision, however accelerating the reattachment of these cells can prevent photoreceptor death and subsequent vision loss. To determine the genes involved in this process, we performed a microarray screen using a mouse model or retinal detachment in conjunction with a P2Y2 agonist previously demonstrated to hasten retinal reattachment.
Expression profiling after retinal detachment and reattachment: a possible role for aquaporin-0.
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Impaired neutrophil function in 24p3 null mice contributes to enhanced susceptibility to bacterial infections.
Sex, Age, Specimen part
View SamplesLipocalin 24p3 (24p3) is a neutrophil secondary granule protein. 24p3 is also a siderocalin, which binds several bacterial siderophores. It was therefore proposed that synthesis and secretion of 24p3 by stimulated macrophages or release of 24p3 upon neutrophil degranulation sequesters iron-laden siderophores to attenuate bacterial growth. Accordingly, 24p3-deficient mice are susceptible to bacterial pathogens whose siderophores would normally be chelated by 24p3. Specific granule deficiency (SGD) is a rare congenital disorder characterized by complete absence of proteins in secondary granules. Neutrophils from SGD patients, who are prone to bacterial infections, lack normal functions but the potential role of 24p3 in neutrophil dysfunction in SGD is not known. Here we show that neutrophils from 24p3-deficient mice are defective in many neutrophil functions. Specifically, neutrophils in 24p3-deficient mice do not extravasate to sites of infection and are defective for chemotaxis. A transcriptome analysis revealed that genes that control cytoskeletal reorganization are selectively suppressed in 24p3-deficient neutrophils. Additionally, small regulatory RNAs (miRNAs) that control upstream regulators of cytoskeletal proteins are also increased in 24p3-deficient neutrophils. Further, 24p3-deficient neutrophils failed to phagocytose bacteria, which may account for the enhanced sensitivity of 24p3-deficient mice to both intracellular (Listeria monocytogenes) and extracellular (Candida albicans, Staphylococcus aureus) pathogens. Interestingly, Listeria does not secrete siderophores and additionally, the siderophore secreted by Candida is not sequestered by 24p3. Therefore, the heightened sensitivity of 24p3-deficient mice to these pathogens is not due to sequestration of siderophores limiting iron availability, but is a consequence of impaired neutrophil function.
Impaired neutrophil function in 24p3 null mice contributes to enhanced susceptibility to bacterial infections.
Sex, Age, Specimen part
View SamplesRetinoic 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 experiment aims to identify mRNAs illustrating the unique nature of the gd T-cell subtype
Human Vδ2 T cells are a major source of interleukin-9.
Specimen part
View SamplesWe initiated a study to investigate the transcriptional profiles associated with cell states of the stomatal lineage. A stem-cell like precursor of stomata, a meristemoid. reiterates asymmetric divisions and renews itself before differentiating into guard cells. The transient and asynchronous nature of the meristemoid has made it difficult to study its molecular characteristics. Through combinatorial use of genetic resources that either arrest or constitutively drive stomatal cell-state progressions due to loss- or gain-of-function mutations in the key transcription factor genes, SPEECHLESS, MUTE, and SCRM, we obtained seedlings highly enriched in pavement cells, meristemoids, or stomata. Here we present transcriptome and genome-wide trends in gene regulation associated with each cell state and identify molecular signatures associated with meristemoids.
Molecular profiling of stomatal meristemoids reveals new component of asymmetric cell division and commonalities among stem cell populations in Arabidopsis.
Age, Specimen part
View SamplesWildtype B6, Rag1-/- B6 and Rag1-/- B6 mice harboring the 225.4 IgA producing hybridoma were colonized for 10 days with Bacteroides thetaiotaomicron
IgA response to symbiotic bacteria as a mediator of gut homeostasis.
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View SamplesCovalently closed circular RNA molecules (circRNAs) have recently emerged as a class of RNA isoforms with widespread and tissue specific expression across animals, oftentimes independent of the corresponding linear mRNAs. circRNAs are remarkably stable and sometimes highly expressed molecules. Here, we sequenced RNA in human peripheral whole blood to determine the potential of circRNAs as biomarkers in an easily accessible body fluid. We report the reproducible detection of thousands of circRNAs. Importantly, we observed that hundreds of circRNAs are much higher expressed than corresponding linear mRNAs. Thus, circRNA expression in human blood reveals and quantifies the activity of hundreds of coding genes not accessible by classical mRNA specific assays. Our findings suggest that circRNAs could be used as biomarker molecules in standard clinical blood samples. Overall design: Sequencing of blood RNA from five healthy individuals (biological replicates) plus technical replicate of one sample and detection of circRNAs.
Identification and Characterization of Circular RNAs As a New Class of Putative Biomarkers in Human Blood.
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View SamplesDifferential expression was used to access gene differences after Entamoeba histolytica infection.
The expression of REG 1A and REG 1B is increased during acute amebic colitis.
Specimen part
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