Expression Profiling of a Genetic Animal Model of Depression Reveals Novel Molecular Pathways Underlying Depressive-like Behaviours
Expression profiling of a genetic animal model of depression reveals novel molecular pathways underlying depressive-like behaviours.
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View SamplesMajor- and minor-group rhinoviruses enter their host by binding to the cell surface molecules ICAM-1 and LDL-R, respectively, which are present on both macrophages and epithelial cells. Although epithelial cells are the primary site of productive HRV infection, previous studies have implicated macrophages in establishing the cytokine dysregulation that occurs during rhinovirus-induced asthma exacerbations. Even though major- and minor-group rhinoviruses are nearly genetically identical, these viruses do not replicate with equal success in monocyte-lineage cell lines. In human primary macrophages, differential mitochondrial activity and signaling pathway activation was observed between major- and minor-group rhinovirus upon initial HRV binding, indicating discordant receptor-dependent response to these rhinovirus types. As well, variances in phosphorylation of kinases (p38, JNK, ERK5) and transcription factors (ATF-2, CREB, CEBP-alpha) were observed between the major- and minor- group HRV treatments. The difference between major- and minor- group HRV activation of signaling pathways was confirmed through RNA-sequencing and observation of differential production of the asthma-relevant cytokines CCL20, CCL2, and IL-10. This is the first report of genetically similar viruses eliciting dissimilar cytokine release, transcription factor phosphorylation, and MAPK activation from macrophages. These results suggest that receptor dependence plays a role in establishing the inflammatory microenvironment initiated in part by monocytic-lineage cells in the human airway upon exposure to rhinovirus. Overall design: RNA sequencing of monocyte-derived macrophages after mock infection or infection by HRV16 or HRV1A
Major and minor group rhinoviruses elicit differential signaling and cytokine responses as a function of receptor-mediated signal transduction.
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View SamplesExercise enhances cognitive function and slows progressive neurodegenerative disease. While exercise promotes neurogenesis, oligodendrogenesis and adaptive myelination are also significant contributors to brain repair and brain health. Nonetheless, the molecular details underlying these effects remain poorly understood. Conditional ablation of the Snf2h gene (Snf2h cKO) impairs cerebellar development producing mice with poor motor function, progressive ataxia and death between postnatal day 25 to 45. Here we show that voluntary running induced an endogenous brain repair mechanism that resulted in a striking increase in hindbrain myelination and the long-term survival of Snf2h cKO mice. Further experiments identified the VGF growth factor as a major driver underlying this effect. VGF neuropeptides could promote oligodendrogenesis in vitro, while Snf2h cKO mice treated with full-length VGF-encoding adenoviruses obliterated the requirement of exercise for survival. Together, these results suggest that VGF delivery could represent a therapeutic strategy for cerebellar ataxia and other pathologies of the central nervous system. Overall design: 4 samples per genotype in biological replicates (8 paired-end libraries)
Voluntary Running Triggers VGF-Mediated Oligodendrogenesis to Prolong the Lifespan of Snf2h-Null Ataxic Mice.
Sex, Specimen part, Cell line, Subject
View SamplesStudy of HP1 Knock Down on gene expression and splicing regulation in Human HeLa cells
Histone H3 lysine 9 trimethylation and HP1γ favor inclusion of alternative exons.
Cell line
View SamplesBoth embryonic and adult zebrafish Mycobacterium marinum infection studies have contributed to our knowledge of the development and function of tuberculous granulomas, which are typical for mycobacterial pathogenesis. In this review we discuss how transcriptome profiling studies have helped to characterize this infection process and we include new RNA sequencing (RNA-Seq) data that reveals three main phases in the host response to M. marinum during the early stages of granuloma development in zebrafish embryos and larvae. The late-phase response shares common components with the strong and acute host transcriptome response that has previously been reported for S. typhimurium infection in zebrafish embryos. In contrast, the early/mid-phase response to M. marinum infection, characterized by suppressed pro-inflammatory signaling, is strikingly different from the acute response to S. typhimurium infection. Furthermore, M. marinum infection shows a collective and strongly fluctuating regulation of lipoproteins, while S. typhimurium infection has pronounced effects on amino acid metabolism and glycolysis. Overall design: Embryos were infected at 28 hpf by injecting 250 colony forming units of M. marinum Mma20 in 2%PVP into the caudal vein, or mock-injected with PBS/2%PVP. After injections, embryos were transferred into fresh egg water containing 0.003% 1-phenyl-2-thiourea (Sigma-Aldrich) to prevent melanization and incubated at 28°C. After the incubation period, infected and uninfected groups of 30 embryos were snap-frozen in liquid nitrogen and RNA was isolated for Illumina RNAseq analysis. Samples were taken at the following timepoints: 2, 4, 6, 8 hpi and 1, 2, 3, 4, 5 dpi.
Transcriptomic Approaches in the Zebrafish Model for Tuberculosis-Insights Into Host- and Pathogen-specific Determinants of the Innate Immune Response.
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View SamplesHuman peroxisome biogenesis disorders are lethal genetic disease in which abnormal peroxisome assembly compromises overall peroxisome and cellular function. Peroxisomes are ubiquitous membrane-bound organelles involved in several important biochemical processes, notably lipid metabolism and the use of reactive oxygen species for detoxification. Using cultured cells, we systematically characterized the peroxisome assembly phenotypes associated with dsRNA-mediated knockdown of 14 predicted Drosophila homologs of PEX genes (encoding peroxins; required for peroxisome assembly and linked to peroxisome biogenesis disorders), and confirmed that at least 13 of them are required for normal peroxisome assembly. We also demonstrate the relevance of Drosophila as a genetic model for the early developmental defects associated with the human peroxisome biogenesis disorders. Mutation of the PEX1 gene is the most common cause of peroxisome biogenesis disorders and is one of the causes of the most severe form of the disease, Zellweger syndrome. Inherited mutations in Drosophila Pex1 correlate with reproducible defects during early development. Notably, Pex1 mutant larvae exhibit abnormalities that are analogous to those exhibited by Zellweger syndrome patients, including developmental delay, poor feeding, severe structural abnormalities in the peripheral and central nervous systems, and early death. Finally, microarray analysis defined clusters of genes whose expression varied significantly between wild-type and mutant larvae, implicating peroxisomal function in neuronal development, innate immunity, lipid and protein metabolism, gamete formation, and meiosis.
A Drosophila model for the Zellweger spectrum of peroxisome biogenesis disorders.
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View SamplesThe roles of RNA-binding proteins as chaperones in the lifecycles of mRNAs are not well understood. The mammalian mitochondrial genome has been compressed over evolution to a size of just 16 kb, nevertheless the expression of its genes requires transcription, RNA processing, translation and RNA decay, much like the more complex chromosomal systems, providing an opportunity to use it as a model system to understand the fundamental aspects of gene expression. Here we combine RNase footprinting with PAR-CLIP at unprecedented depth to reveal the importance of RNA-protein interactions guided by the LRPPRC/SLIRP complex in dictating RNA folding within the mitochondrial transcriptome. We show that LRPPRC, in complex with its protein partner SLIRP, binds throughout the mitochondrial transcriptome, with a preference for mRNAs, and its loss affects the entire secondary structure and stability of the transcriptome. We demonstrate that the LRPPRC/SLIRP complex is a global RNA chaperone that stabilizes RNA structures to expose the required sites for translation, stabilization and polyadenylation. Our findings reveal a general mechanism where extensive RNA-protein interactions ensure that RNA is accessible for its biological functions. Overall design: RNase footprinting of LRPPRC and SLIRP knockout and control mice, in technical duplicate.
LRPPRC-mediated folding of the mitochondrial transcriptome.
Specimen part, Cell line, Subject
View SamplesMacrophage expressed gene 1 (MPEG1) encodes an evolutionary conserved protein with a predicted Membrane Attack Complex/Perforin domain associated with host defence against invading pathogens. In vertebrates, MPEG1 is an integral membrane protein of macrophages, but how it contributes to the macrophage defence mechanisms remains unknown. Zebrafish have three copies of MPEG1, two of which (mpeg1 and mpeg1.2) are expressed in macrophages whereas the third could be a pseudogene. The mpeg1 and mpeg1.2 genes show differential regulation during infection of zebrafish embryos with the bacterial pathogens, Mycobacterium marinum and Salmonella typhimurium. While mpeg1 is down-regulated during infection with both pathogens, mpeg1.2 is infection inducible. Up-regulation of mpeg1.2 is partially dependent on the presence of functional Mpeg1, and requires the Toll-like receptor adaptor molecule MyD88 and transcription factor NF?B. Knockdown of mpeg1 alters the immune response to M. marinum infection and results in increased bacterial burden. In S. typhimurium infection, both mpeg1 and mpeg1.2 knockdown increase bacterial burdens, but mpeg1 morphants show an increased survival rate. The combined results of these two in vivo infection models support the anti-bacterial function of the Mpeg1 family and indicate that the intricate cross-regulation of the two mpeg1 copies aids the zebrafish host in combatting infection Overall design: Embryos were injected at the one cell stage with a morpholino targeting mpeg1, or with the standard control morpholino from GeneTools, or with a morpholino targeting ptpn6 (Kanwal et al., 2013, J. Immunol 190:1631-45) for comparison. Subsequently, at 24 hours post fertilisation (hpf) the morphants and their controls were manually dechorionated at 24 hpf and at 28 hpf they were infected by injecting 200 colony forming units of M. marinum Mma20 into the caudal vein, or mock-injected with PBS/2%PVP. After injections embryos were transferred into fresh egg water containing 0.003% 1-phenyl-2-thiourea (Sigma-Aldrich) to prevent melanisation and incubated for 4 days at 28°C. After the incubation period, infected and uninfected morphants, mutants and their controls were imaged and groups of 30 embryos were snap-frozen in liquid nitrogen and RNA was isolated for Illumina RNAseq analysis.
Macrophage-expressed perforins mpeg1 and mpeg1.2 have an anti-bacterial function in zebrafish.
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View SamplesMyD88 is an adaptor protein in Toll-like receptor and interleukin 1 receptor mediated signaling pathways that plays an essential role in activation of immune responses following pathogen recognition. We investigate that role in the zebrafish embryo model by using a zebrafish mutant line that contains a premature stop condon in the gene encoding MyD88, leading to a truncated protein that lacks domains important for its normal function. We infected these MyD88 mutants and wildtype individuals with Mycobacterium marinum to compare the resulting immune response by transcriptome profiling on total RNA isolated from single embryos. Autophagy regulator dram1 was identified as one of the MyD88-dependent genes. Overall design: This RNAseq analysis was used to determine the effect of a truncation of the MyD88 protein on the innate immune response of zebrafish embryos during infection with Mycobacterium marinum. Myd88 mutant and wild type embryos were derived by incrossing homozygous myd88 mutant parents (allele hu3568, van der Vaart et al., 2013, Disease models & mechanisms 6, 841-854) or their wildtype siblings. RNA was isolated from pools of 20 embryos at 4 days post infection (4 dpi). The following treatment groups were used: homozygous mutants mock-injected with PBS/2%PVP 4 dpi, (2) wildtype siblings mock-injected with PBS/2%PVP 4dpi, (3) M. marinum-infected homozygous mutants 4dpi, (4) M. marinum-infected wildtype siblings 4dpi. Embryos were grown at 28.5–30°C in egg water and manually dechorionated at 24 hours post fertilization (hpf). Subsequently, embryos were infected at 28 hpf by micro-injecting 200 colony forming units (CFU) of Mycobacterium marinum Mma20 bacteria into the caudal vein, or were mock-injected with buffer (PBS/2%PVP) as a control. After injections embryos were transferred into fresh egg water and incubated for 4 days at 28°C. After the incubation period, single embryos were snap-frozen in liquid nitrogen and RNA was isolated for RNAseq analysis.
Macrophage-expressed perforins mpeg1 and mpeg1.2 have an anti-bacterial function in zebrafish.
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View SamplesCells are constantly exposed to stress. Most of those stresses do not necessarily cause cell death or visible damage. The present study explores the way the immune system responds to such sub lethal stressed cells.
Cells exposed to sublethal oxidative stress selectively attract monocytes/macrophages via scavenger receptors and MyD88-mediated signaling.
Specimen part, Treatment
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