Both 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 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 SamplesWe used zebrafish embryos as an in vivo system to investigate the role of the microRNA-146 family (consisting of 2 members miR-146a and miR-146b) in the innate immune response to S. typhimurium infection. To determine the role of miR-146 microRNAs in the response to S. typhimurium infection we used Illumina RNA sequencing to compare the mRNA expression profiles of control embryos versus embryos with knockdown of miR-146a and miR-146b. RNA sequencing analysis of miR-146 knockdown embryos showed no major effects on pro-inflammatory gene expression or on the expression of transcriptional regulators and signal transduction components of the immune response. In contrast, apoliprotein-mediated lipid transport emerged as an infection-inducible pathway under miR-146 knockdown conditions, suggesting a function of miR-146 in regulating lipid metabolism during inflammation. Overall design: Embryos were injected at the one cell stage with a combination of two morpholinos targeting miR-146a and miR-146b, or with the standard control morpholino from GeneTools. Subsequently, at 28 hours post fertilzation (hpf) they were infected by injecting 200-250 colony forming units of S. typhimurium strain SL1027 into the caudal vein, or mock-injected with PBS. RNA was isolated at 8 hours post injection (hpi) for Illumina RNAseq analysis. Two independent experiments were performed for RNAseq analysis of biological duplicates.
MicroRNA-146 function in the innate immune transcriptome response of zebrafish embryos to Salmonella typhimurium infection.
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View SamplesWe used different zebrafish transgenic lines to sort macrophages, neutrophils and immature lymphoid cells from 5-6 day old zebrafish larvae and analyzed their transcriptomes. Comparison between the different transcriptomes and gene ontology analysis revealed specificities for each cell population. Comparison with previously published data showed that zebrafish larval macrophages expressed several known human M1 and M2 macrophages. Transcriptome analysis of uninfected and infected macrophages from embryos infected by of Mycobacterium marinum revealed infection induced transcriptional changes and a shift towards M1 transcriptomic signature. Overall design: Embryos were grown into egg water refresh every day and incubated for 5 or 6 days at 28°C. 0.003% 1-phenyl-2-thiourea (Sigma-Aldrich) was added after 1 day to prevent melanisation. After the incubation period, embryos were dissociated into single cell suspension by Trypsin treatment and fluorescent cells were sorted by FACS. RNA extraction and library preparation were performed as previously described. (Rougeot et al., 2014, Methods Mol Biol 1197:41-66). For infection experiments, zebrafish embryos were manually dechorionated at 24 hours post fertilization (hpf) and were infected by injection in the caudal vein of 125 colony forming unit of Mycobacterium marinum M strain expressing GFP. Infected larvae were collected for FACS sorting 5 day post infection.
Corrigendum: RNAseq Profiling of Leukocyte Populations in Zebrafish Larvae Reveals a <i>cxcl11</i> Chemokine Gene as a Marker of Macrophage Polarization During Mycobacterial Infection.
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View SamplesChromodomains are found in many regulators of chromatin structure. Most of them recognize methylated histones. Here, we investigate the role of the Corto chromodomain. This Drosophila melanogaster Enhancer of Polycomb and Trithorax is involved in both silencing and activation of gene expression. Overexpression of Corto chromodomain (CortoCD) in transgenic flies show that this domain is critical for Corto function and behaves as a chromatin-targeting module. Mass spectrometry analysis of peptides pulled down by CortoCD from nuclear extracts reveals that they correspond to nuclear ribosomal proteins (RPs). Notably, CortoCD binds with high affinity RPL12 tri-methylated on lysine 3 (RPL12K3me3) as demonstrated by real-time interaction analyses. Co-localization of Corto and RPL12 with active epigenetic marks on polytene chromosomes suggests that they are involved in fine-tuning transcription of genes located in open chromatin. Hence, pseudo-ribosomal complexes composed of various RPs might participate in regulation of gene expression in connection with chromatin regulators. RNA-seq analysis of wing imaginal discs overexpressing either Corto or RPL12 show that most deregulated genes are shared by both factors. Interestingly, these common targets are enriched in RP genes suggesting that Corto and RPL12 are involved in dynamic coordination of ribosome biogenesis. Overall design: To address the role of Corto and RPL12 in regulation of transcription, we deep-sequenced transcripts of wing imaginal discs from third instar larvae over-expressing either FH-cortoCD or RpL12-Myc under control of the wing-specific scalloped::Gal4 driver (sd::Gal4>UAS::FH-cortoCD or sd::Gal4>UAS::RpL12-Myc). Total RNA from FH-cortoCD or RpL12-Myc, the sd::Gal4/+ control or a w1118 reference line were isolated from pools of wing imaginal discs and subjected to RNA-seq on an Illumina high throughput sequencer.
New partners in regulation of gene expression: the enhancer of Trithorax and Polycomb Corto interacts with methylated ribosomal protein l12 via its chromodomain.
Specimen part, Subject
View SamplesThe spatial and temporal control of Hox gene transcription is essential for patterning the vertebrate body axis. Although this process involves changes in histone posttranslational modifications, the existence of particular three-dimensional (3D) architectures remained to be assessed in vivo. Using high-resolution chromatin conformation capture methodology, we examined the spatial configuration of Hox clusters in embryonic mouse tissues where different Hox genes are active. When the cluster is transcriptionally inactive, Hox genes associate into a single 3D structure delimited from flanking regions. Once transcription starts, Hox clusters switch to a bimodal 3D organization where newly activated genes progressively cluster into a transcriptionally active compartment. This transition in spatial configurations coincides with the dynamics of chromatin marks, which label the progression of the gene clusters from a negative to a positive transcription status. This spatial compartmentalization may be key to process the collinear activation of these compact gene clusters.
The dynamic architecture of Hox gene clusters.
Specimen part
View SamplesTORC1 is a structurally and functionally conserved multiprotein complex that regulates many aspects of eukaryote growth including the synthesis and assembly of ribosomes. The protein kinase activity of this complex is responsive to environmental cues and is potently inhibited by the natural product macrolide rapamycin. Insights into how TORC1 regulates growth have been provided with the recent identification of the rapamycin-sensitive phosphoproteome in yeast. Building on these data, we show here that Sch9, an AGC family kinase and direct substrate of TORC1, promotes ribosome biogenesis (ribi) and ribosomal protein (RP) gene expression via direct inhibitory phosphorylation of three transcription repressors, Stb3, Dot6 and Tod6. Dephosphorylation of these factors allows them to recruit the RPD3L histone deactelyase complex to ribi/RP gene promoters. Since rRNA and tRNA transcription are also under its control, Sch9 appears to be well positioned to coordinately regulate transcriptional aspects of ribosome biogenesis. Overall design: mRNA-Seq of 8 S. cerevisiae strains treated with either DMSO alone or 1NM-PP1, a small molecule inhibitor for analog-sensitive kinases such as sch9-as.
Sch9 regulates ribosome biogenesis via Stb3, Dot6 and Tod6 and the histone deacetylase complex RPD3L.
Specimen part, Cell line, Treatment, Subject
View SamplesPurpose: The population of muscle-derived stem cells called MuStem cells is presented as promising candidate for cell-based therapy of muscle diseases. To validate if this agent can be really presented as therapeutic product and so to be eligible to a future clinical use, it is now required to demonstrate beforehand an efficacy with cells prepared in compliance with good manufacturing practices (GMPs). The aim of the current study was to evaluate the use of two xeno-free blood derivatives corresponding to human serum (HS) and human platelet lysate (hPL) as alternatives to controverted but until now used fetal bovine serum (FBS) for isolation and expansion of human MuStem (hMuStem) cells. Methods: A comparative study was performed with hMuStem cells isolated and in vitro expanded by using commercially available HS and hPL to determine its impact on their proliferation rates, clonogenicity, myogenic commitment level and oligopotency with regard to results obtained under FBS-based medium. Also, their respective phenotype and global gene expression patterns were investigated by flow cytometry and high throughput 3' digital gene expression RNA-sequencing in order to define a possible differential impact of the human nutrients tested. Results: Comparatively to FBS-based medium, use of HS- and hPL-supplemented ones efficiently supported long-term proliferation of hMuStem cells and enhanced clonogenicity, without main modification of their expression profile and allowing besides limiting the supplementation in growth factors. In vitro differentiation assay combined to transforming growth factor ß1 (TGF-ß1)-depletion experiments showed a lower myogenic commitment level as well as fusion ability of hMuStem cells when cultured with hPL-based medium according to a TGF-ß1-independent process. Use of hPL-derived 3D hydrogel or fibrinogen-depleted hPL demonstrated that heparin-free hPL derivatives maintain consequent myogenic differentiation potential. In addition, the reduced myogenicity was shown to be rapidly reversible following replacement of hPL by HS or fibrinogen-depleted hPL. Conclusions: All together, our original findings position HS and hPL as efficient and suitable alternatives to FBS for preparation of hMuStem cell batch in compliance with GMPs. Overall design: mRNA profile of hMuStem cells cultured in hPL was compared to the mRNA profile of hMuStem cells cultured in HS. The profiles were generated in triplicates using the 3''DGE-Seq technology.
Human serum and platelet lysate are appropriate xeno-free alternatives for clinical-grade production of human MuStem cell batches.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Phytochrome interacting factors 4 and 5 control seedling growth in changing light conditions by directly controlling auxin signaling.
Age, Specimen part, Treatment
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