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A balance between secreted inhibitors and edge-sensing controls gastruloid self-organization
The earliest aspects of human embryogenesis remain mysterious. To model patterning events in the human embryo we used colonies of human embryonic stem cells (hESCs) grown on micropatterned substrate and differentiated with BMP4. These recapitulate the embryonic arrangement of the mammalian germ layers and provide an assay to assess the structural and signaling mechanisms patterning the human gastrula. Structurally, high-density hESCs relocalize their TGF-β receptors to their lateral side in the center of the colony, while maintaining apical localization of receptors at the edge. This relocalization insulates central cells from apically applied ligands while maintaining response to basally presented ones. Additionally, BMP4 directly induces the expression of its own inhibitor, Noggin, generating a reaction-diffusion mechanism that underlies patterning. We develop a quantitative model that integrates edge sensing and inhibitors, to predict human fate positioning in micropatterns, and potentially the human embryo.
Human leukocytes from 6 volunteers before and 2h after pectin capsules consumption (I)
Methanol (MeOH) is considered to be a poison in humans because of the alcohol dehydrogenase (ADH)-mediated conversion of MeOH into toxic formaldehyde (FA). Our recent genome-wide analysis of the mouse brain demonstrated that an increase in endogenous MeOH after ADH inhibition led to a significant increase in the plasma MeOH concentration and the modification of mRNA synthesis. These findings suggest endogenous MeOH involvement in homeostasis regulation by controlling mRNA levels. Here, we demonstrate directly that study volunteers displayed increasing concentrations of MeOH and FA in their blood plasma when consuming citrus pectin, ethanol and red wine. A microarray analysis of white blood cells (WBC) in volunteers after pectin intake showed various responses for 30 differentially regulated mRNAs. Most of the mRNAs were somehow involved in the pathogenesis of Alzheimer's disease (AD). There was also a decreased synthesis of hemoglobin mRNA, HBA and HBB, the presence of which in WBC RNA was not a result of red blood cells contamination because erythrocyte-specific marker genes did not show significant change. A qRT-PCR analysis of volunteer WBC after pectin and red wine intake confirmed the complicated dependence between plasma MeOH content and the mRNA accumulation of previously identified genes, namely GAPDH and SNX27, and MME, SORL1, DDIT4, HBA and HBB genes revealed in this study. We hypothesized that human plasma MeOH, which is replenished from endogenous and exogenous sources (diet), has an impact on the WBC mRNA levels of genes involved in AD pathogenesis and signaling.
Human leukocytes from 6 volunteers before and 2h after pectin capsules consumption (II)
Methanol (MeOH) is considered to be a poison in humans because of the alcohol dehydrogenase (ADH)-mediated conversion of MeOH into toxic formaldehyde (FA). Our recent genome-wide analysis of the mouse brain demonstrated that an increase in endogenous MeOH after ADH inhibition led to a significant increase in the plasma MeOH concentration and the modification of mRNA synthesis. These findings suggest endogenous MeOH involvement in homeostasis regulation by controlling mRNA levels. Here, we demonstrate directly that study volunteers displayed increasing concentrations of MeOH and FA in their blood plasma when consuming citrus pectin, ethanol and red wine. A microarray analysis of white blood cells (WBC) in volunteers after pectin intake showed various responses for 30 differentially regulated mRNAs. Most of the mRNAs were somehow involved in the pathogenesis of Alzheimer's disease (AD). There was also a decreased synthesis of hemoglobin mRNA, HBA and HBB, the presence of which in WBC RNA was not a result of red blood cells contamination because erythrocyte-specific marker genes did not show significant change. A qRT-PCR analysis of volunteer WBC after pectin and red wine intake confirmed the complicated dependence between plasma MeOH content and the mRNA accumulation of previously identified genes, namely GAPDH and SNX27, and MME, SORL1, DDIT4, HBA and HBB genes revealed in this study. We hypothesized that human plasma MeOH, which is replenished from endogenous and exogenous sources (diet), has an impact on the WBC mRNA levels of genes involved in AD pathogenesis and signaling.
GATA3 acts upstream of FOXA1 in mediating ER binding by shaping enhancer accessibility
Estrogen Receptor (ESR1) drives growth in the majority of human breast cancers by binding to regulatory elements and inducing transcription events that promote tumor growth. Differences in enhancer occupancy by ESR1, contribute to the diverse expression profiles and clinical outcome observed in breast cancer patients. GATA3 is an ESR1 co-operating transcription factor mutated in breast tumors, however its genomic properties are not fully defined. In order to investigate the composition of enhancers involved in estrogen-induced transcription and the potential role of GATA3, we performed extensive ChIP-sequencing in unstimulated breast cancer cells and following estrogen treatment. We find that GATA3 is pivotal in mediating enhancer accessibility at regulatory regions involved in ESR1-mediated transcription. GATA3 silencing resulted in a global redistribution of co-factors and active histone marks prior to estrogen stimulation. These global genomic changes altered the ESR1 binding profile that subsequently occurred following estrogen, with events exhibiting both loss and gain in binding affinity, implying a GATA3 mediated re-distribution of ESR1 binding. The GATA3-mediated re-distributed ESR1 profile correlated with changes in gene expression, suggestive of its functionality. Chromatin loops at the TFF locus involving ESR1 bound enhancers occurred independently of ESR1 when GATA3 was silenced, indicating that GATA3, when present on the chromatin, may serve as a licensing factor for estrogen- ESR1 mediated interactions between cis-regulatory elements. Together these experiments suggest that GATA3 directly impacts ESR1 enhancer accessibility and may potentially explain the contribution of mutant-GATA3 in the heterogeneity of ESR1+ breast cancer.
Genoma-wide analysis of pro- and anti-inflammatory activation states in embryonic stem cell-derived microglia
Embryonic stem cell derived microglia (ESdM) were treated with different inflammatory stimulants to analyze their ability to adopt different activation states. Abstract: Microglia, the immune cells of the CNS, are highly adaptive cells that can acquire different pro- and anti-inflammatory activation states with distinct functions in CNS homeostasis and pathologies. To study microglial function in vitro, primary microglia or immortalized cell lines are commonly used. An alternative to these cells are embryonic stem cell-derived microglia (ESdM). ESdM have previously been shown to be very similar to primary microglia in terms of expression profiles and surface molecules. In this study, ESdM and primary microglia were treated with different inflammatory stimulants to analyze their ability to adopt different activation states. Using quantitative real time PCR, comparative transcriptomics, ELISA, and flow cytometry, we found that different activation states can be induced in ESdM, which are similar to those found in primary microglia. These states are characterized by specific sets of inflammatory marker molecules and differential transcriptome signatures. Our results show that ESdM are a valuable alternative cell model to study microglial functions and neuroinflammatory mechanisms.
Regulation of epidermal growth factor receptor signaling and erlotinib sensitivity in head and neck cancer cells by miR-7
Elevated expression and activity of the epidermal growth factor receptor (EGFR)/protein kinase B (Akt) signaling pathway is associated with development, progression and treatment resistance of head and neck cancer (HNC). Several studies have demonstrated that microRNA-7 (miR-7) regulates EGFR expression and Akt activity in a range of cancer cell types via its specific interaction with the EGFR mRNA 3′ untranslated region (3′-UTR). In the present study, we found that miR-7 regulated EGFR expression and Akt activity in HNC cell lines, and that this was associated with reduced growth in vitro and in vivo of cells (HN5) that were sensitive to the EGFR tyrosine kinase inhibitor (TKI) erlotinib (Tarceva). miR-7 acted synergistically with erlotinib to inhibit growth of erlotinib-resistant FaDu cells, an effect associated with increased inhibition of Akt activity. Microarray analysis of HN5 and FaDu cell lines transfected with miR-7 identified a common set of downregulated miR-7 target genes, providing insight into the tumor suppressor function of miR-7. Furthermore, we identified several target miR-7 mRNAs with a putative role in the sensitization of FaDu cells to erlotinib. Together, these data support the coordinate regulation of Akt signaling by miR-7 in HNC cells and suggest the therapeutic potential of miR-7 alone or in combination with EGFR TKIs in this disease.
Genoma-wide analysis of pro- and anti-inflammatory activation states in primary microglia.
Murine primary microglia were treated with different inflammatory stimulants to induce different activation states and analyze the associated transcriptional changes. Abstract: Microglia, the immune cells of the CNS, are highly adaptive cells that can acquire different pro- and anti-inflammatory activation states with distinct functions in CNS homeostasis and pathologies. To study microglial function in vitro, primary microglia or immortalized cell lines are commonly used. An alternative to these cells are embryonic stem cell-derived microglia (ESdM). ESdM have previously been shown to be very similar to primary microglia in terms of expression profiles and surface molecules. In this study, ESdM and primary microglia were treated with different inflammatory stimulants to analyze their ability to adopt different activation states. Using quantitative real time PCR, comparative transcriptomics, ELISA, and flow cytometry, we found that different activation states can be induced in ESdM, which are similar to those found in primary microglia. These states are characterized by specific sets of inflammatory marker molecules and differential transcriptome signatures. Our results show that ESdM are a valuable alternative cell model to study microglial functions and neuroinflammatory mechanisms.
Synthetic cationic peptide IDR-1018 modulates human macrophage differentiation
Synthetic, innate defense regulators (IDR) peptides, designed based on natural host defenses peptides, have enhanced immunomodulatory activities and reduced toxicity leading to protection in infection and inflammation models that is dependent on macrophages/monocytes. Here we measured the effect of IDR-1018 on macrophage gene expression during differentiation. Differentiation in the presence of IDR-1018 induced a unique signature of immune responses suggesting that IDR-1018 drives macrophage differentiation towards an intermediate M1-M2 state, enhancing anti-inflammatory functions while maintaining certain pro-inflammatory activities important to the resolution of infection.
ALKBH5 is a New Mammalian RNA Demethylase
N6-methyladenosine (m6A) is the most prevalent internal modification of messenger RNA (mRNA) in higher eukaryotes. Here we report ALKBH5 as a new mammalian demethylase that oxidatively removes the m6A modification in mRNA in vitro and inside cells. This demethylation activity of ALKBH5 significantly affects mRNA export and RNA metabolism as well as the assembly of mRNA processing factors in nuclear speckles. Alkbh5-deficient male mice are characterized by impaired fertility resulting from apoptosis that affects meiotic metaphase-stage spermatocytes. In accordance with this defect, we have identified in mouse testes 1552 differentially expressed genes which cover broad functional categories and include spermatogenesis-related mRNAs involved in the p53 functional interaction network. We show that Alkbh5-deficiency impacts the expression levels of some of these mRNAs, supporting the observed phenotype. The discovery of this new RNA demethylase strongly suggests that the reversible m6A modification plays fundamental and broad functions in mammalian cells.
Structural basis of YTH domain as m6A reader
The N6-methyladenosine (m6A) is the most abundant internal modification in almost all eukaryotic messenger RNAs, and is dynamically regulated. Therefore, identification of m6A readers is especially important in determining the cellular function of m6A. YTHDF2 has recently been characterized as the first m6A reader that regulates the cytoplasmic stability of methylated RNA. Here we show that YTHDC1 is a nuclear m6A reader and report the crystal structure of the YTH domain of YTHDC1 bound to m6A-containing RNA. We further determined the structure of another YTH domain, YTHDF1, and found that the YTH domain utilizes a conserved aromatic cage to specifically recognize the methyl group of m6A. Our structural characterizations of the YTHDC1-m6A RNA complex also shed light on the molecular basis for the preferential binding of the GG(m6A)C sequence by YTHDC1 and confirm the YTH domain as a specific m6A RNA reader.
Genome-wide analysis of DNA methylation in grapevine fruits
To examine the grapevine genomic methylation landscape and assess its functional significance, we generated whole genome DNA methylome maps for grapevine fruits of developmental stages. The results showed that DNA methylation happened in the grapevine fruit ripening process, and mostly happened in the biological process from the first growth stage fruit transfer to the véraison stage fruit. It further demonstrated that DNA methylation repress the gene expression. The whole-genome methylomes of grapevine fruits obtained in this study have not only broadened our understanding of the mechanism and function of DNA methylation in plant genomes, but also provided valuable data for future studies of grapevine epigenetics and the epigenetic differentiation among different fruit developmental stages.
The Methylomes of Six Bacteria
Six bacterial genomes, Geobacter metallireducens GS-15, Chromohalobacter salexigens, Vibrio breoganii 1C-10, Bacillus cereus ATCC 10987, Campylobacter jejuni subsp. jejuni 81-176 and Campylobacter jejuni NCTC 11168, all of which had previously been sequenced using other platforms were re-sequenced using single-molecule, real-time (SMRT) sequencing specifically to analyze their methylomes. In every case a number of new N6-methyladenine (m6A) and N4-methylcytosine (m4C) methylation patterns were discovered and the DNA methyltransferases (MTases) responsible for those methylation patterns were assigned. In 15 cases it was possible to match MTase genes with MTase recognition sequences without further sub-cloning. Two Type I restriction systems required sub-cloning to differentiate their recognition sequences, while four MTases genes that were not expressed in the native organism were sub-cloned to test for viability and recognition sequences. No attempt was made to detect 5-methylcytosine (m5C) recognition motifs from the SMRT sequencing data because this modification produces weaker signals using current methods. However, all predicted m6A and m4C MTases were detected unambiguously. This study shows that the addition of SMRT sequencing to traditional sequencing approaches gives a wealth of useful functional information about a genome showing not only which MTase genes are active, but also revealing their recognition sequences.
Cleavage Factor Im as a key regulator of 3’ UTR length
In eukaryotes, the 3' ends of RNA polymerase II-generated transcripts are made in the majority of cases by site-specific endonucleolytic cleavage, followed by the addition of a poly(A) tail. By alternative polyadenylation, a gene can give rise to multiple mRNA isoforms that differ in the length of their 3' UTRs and hence in their susceptibility to post-transcriptional regulatory factors such as microRNAs. A series of recently conducted high-throughput studies of poly(A) site usage revealed an extensive tissue-specific control of 3’ UTR length and drastic changes in 3’ UTR length of mRNAs upon induction of proliferation in resting cells. To understand the dynamics of polyadenylation site usage, we recently identified binding sites of the major pre-mRNA 3’ end processing factors - cleavage and polyadenylation specificity factor (CPSF), cleavage stimulation factor (CstF), and cleavage factor Im (CF Im) - and mapped cleaved polyadenylation sites in HEK293 cells. Our present study extends previous findings on the role of CF Im in alternative polyadenylation and reveals that subunits of the CF Im complex generally control 3’ UTR length. More specifically, we demonstrate that the  loss-of-function of CF Im68 and CF Im25 but not of CF Im59 leads to a transcriptome-wide increase of the use of proximal polyadenylation sites.
RNA-sequencing of single whole cells and nuclei from mouse dentate granule cells
Single-cell sequencing methods have emerged as powerful tools for identification of heterogeneous cell types within defined brain regions. Application of single-cell techniques to study the transcriptome of activated neurons can offer insight into molecular dynamics associated with differential neuronal responses to a given experience. Through evaluation of common whole-cell and single-nuclei RNA-sequencing (snRNA-seq) methods, here we show that snRNA-seq faithfully re-capitulates transcriptional patterns associated with experience-driven induction of activity, including immediate early genes (IEGs) such as Fos, Arc, and Egr1. SnRNA-seq of mouse dentate granule cells reveals large-scale changes in the activated neuronal transcriptome after brief novel environment exposure, including induction of MAPK pathway genes . In addition, we observe a continuum of activation states, revealing a pseudo-temporal pattern of activation from gene expression alone. In summary, snRNA-seq of activated neurons enables the examination of gene expression beyond IEGs,allowing for novel insights into neuronal activation patterns in vivo.
Identification of WRKY22 direct targets under submergence in Arabidopsis with ChIP
To identify direct targets of WRKY22, we created a transgenic Arabidopsis line that expresses a c-myc epitope-tagged WRKY22 and used ChIP followed by microarray hybridization (ChIP-chip) to screen for candidates and validate the in vivo protein-DNA interactions with ChIP followed by quantitative PCR (ChIP-Q-PCR). The WRKY22 and c-myc epitope tag fusion construct was generated and transformed into wrky22-ko2 plants. The resulting transgenic lines should have better ChIP efficiency than the wild-type background, due to the reduced competition for WRKY22 binding sites from endogenous WRKY22. ChIP-enriched DNA fragments were identified using criteria of a window of +300 to -1200 of a gene for a promoter, a width of 4 probes or more, and a false discovery rate (FDR) 2 or < 0.5-fold induction in any time point under submergence treatments in expression array data.
α-catulin play a role in lung cancer metastasis
Background: α-catulin may functions as an oncoprotein, sustaining proliferation by preventing cellular senescence and promoting cancer cell migration. In this study, we investigated the mechanism of α-catulin in cancer cell migration and metastasis in lung cancer. Method: α-catulin mRNA expression was isolated from A549/AS2neo (control) and A549/AS2neo-α-catulin stable cells. The Phalanx Human OneArray microarray analysis was performed to identify α-catulin downstream genes. Results: Overexpression of α-catulin increased cancer cell migration and metastasis. By using Phalanx Human OneArray microarray we have identified panel of genes altered by α-catulin overexpression, consisting of CDC42, intergrins and genes related to cytoskeleton remodeling. Conclusion: α-catulin is an oncoprotein and promotes lung cancer cell migration and metastasis.
Identification of NO Response Network in E. coli
The goals of this project were: to use transcriptomics as a starting point for reverse engineering the NO response network of E. coli, and to identify the targets responsible for NO-induced bacteriostasis. The data is associated with Hyduke DR*, Jarboe LR*, Tran LM, Chou KJY, Liao JC 2007 "Integrated network analysis identifies nitric oxide response networks and dihydroxyacid dehydratase as a crucial target in Escherichia coli. "Proc. Natl. Acad. Sci. USA 104(20):8484-8489. Keywords: Comparative genomic response.
Toxicogenomic Responses of Nanotoxicity in Daphnia magna Exposed to Silver Nitrate and Coated Silver Nanoparticles
Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO3 and AgNPs have distinct expression profiles suggesting different modes of toxicity. However, the gene expression profiles of the different coated AgNPs were similar revealing similarities in the cellular effects of these two particles. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO3 caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed.
Daptomycin tolerance in the Staphylococcus aureus pitA6 mutant is due to upregulation of the dlt-operon
It is very important to understand the mechanisms how bacteria become tolerant towards antibiotics during clinical therapy. In a previous study we showed that increased daptomycin (DAP) tolerance of Staphylococcus aureus was due to a point mutation in pitA (inorganic phosphate transporter) that led to intracellular accumulation of both inorganic phosphate (Pi) and polyphosphate (polyP). DAP tolerance in that pitA6 mutant differs from classical resistance mechanisms as there was no increase in minimal inhibitory concentration (MIC). In this study we demonstrate that DAP tolerance in the pitA6 mutant is not triggered by the accumulation of polyP. Transcriptome analysis revealed that about 234 genes were at least 2.0-fold differently expressed in the mutant. Particularly, genes involved in protein biosynthesis, carbohydrate and lipid metabolism as well as in replication and maintenance of DNA were downregulated. However, the most important change was the upregulation of the dlt-operon, which is induced by the accumulation of intracellular Pi. The GraXRS system, known as activator of both dlt and mprF, as well as surface charge, cell wall thickness or the content of wall teichoic acids (WTA) are not involved in DAP tolerance in the pitA6 mutant. In conclusion the DAP tolerance in the pitA6 mutant is due to an upregulation of the dlt-operon triggered directly or indirectly by the accumulation of Pi.
LncRNA expression profiles of 59 tumorous liver tissues derived from patients with hepatocellular carcinoma (HCC)
Long noncoding RNAs (lncRNAs) are a class of non-coding RNAs longer than 200 nt that function in endogenous gene regulation and tumorigenesis. Hepatocellular carcinoma (HCC) is a heterogeneous disease with different treatment outcome. It is a challenge to develop a prognostic marker to identify HCC patients who are at greatest risk for recurrence or death. In this study, we try to screen lncRNAs whose expression levels are associated with recurrence or death of HCC patients through an extensive lncRNA profiling study on a cohort of 59 HCC patients.
Analysis of on-chip hybridization kinetics for optimization of gene expression experiments.
DNA microarray technology is a powerful tool for getting the overview of gene expression in biological samples. Although the successful application of microarray-based expression analysis was demonstrated in a number of applications, the main problem with this approach is the fact that expression levels deduced from hybridization experiments do not necessarily correlate with RNA concentrations. Moreover, oligonucleotide probes corresponding to the same gene can give different hybridization signals. Apart from cross-hybridizations and differential splicing, this could be due to secondary structures of probes or targets. In addition, for low copy genes, hybridization equilibrium may be reached after hybridization times much longer than the one commonly used (overnight, 15 hours). Thus, hybridization signals could depend on kinetic properties of the probe, which may vary between different oligonucleotide probes immobilized on the same microarray. To validate these hypothesis, on-chip hybridization kinetics and duplexes thermostability analysis were performed using oligonucleotide microarrays containing 50-mer probes corresponding to mouse genes. We demonstrate that differences in hybridization kinetics between the probes can influence the interpretation of expression data. Ways to improve the reliability of microarray-based expression analysis are discussed. Keywords: kinetics, gene expression, microarrays
Transcriptomic analysis of wild-type (WT) and curled-cotyledon(cco) mutant in soybean
Soybean is one of the most economically important crops in the world. The cotyledon is the nutrient storage area in seeds, and it is critical for seed quality and yield. Cotyledon mutants are important for the genetic dissection of embryo patterning and seed development.Here, we characterised a soybean curled-cotyledon (cco) mutant. Compared with wild-type (WT), the entire embryos of cco mutant resembled the “tail of swallow”. To explore the molecular mechanisms underlying soybean cotyledon development, we executed RNA-Seq using the Illumina HiSeq2000 system.
Distinct effects of p19 RNA silencing suppressor on small RNA mediated pathways in plants
RNA silencing is one of the main defense mechanisms employed by plants to fight viruses. In change, viruses have evolved silencing suppressor proteins to neutralize antiviral silencing. Since the endogenous and antiviral functions of RNA silencing pathway rely on common components, it was suggested that viral suppressors interfere with endogenous silencing pathway contributing to viral symptom development. In this work, we aimed to understand the effects of the tombusviral p19 suppressor on endogenous and antiviral silencing during genuine virus infection. We showed that ectopically expressed p19 sequesters endogenous small RNAs (sRNAs) in the absence, but not in the presence of virus infection. Our presented data question the generalized model in which the sequestration of endogenous sRNAs by the viral suppressor contributes to the viral symptom development. We further showed that p19 preferentially binds the perfectly-paired ds-viral small interfering RNAs (vsiRNAs) but does not select based on their sequence or the type of the 5’ nucleotide. Finally, co-immunoprecipitation of sRNAs with AGO1 or AGO2 from virus-infected plants revealed that p19 specifically impairs vsiRNA loading into AGO1 but not AGO2. Our findings, coupled with the fact that p19-expressing wild type Cymbidium ringspot virus (CymRSV) overcomes the Nicotiana benthamiana silencing based defense killing the host, suggest that AGO1 is the main effector of antiviral silencing in this host-virus combination. To further support our hypothesis we investigate whether the ability of p19 to bind endogenous sRNA without virus infection has biological important impact on endogenous pathways and is this reduced if the virus is present. To asses this we made mRNA sequencing from mock inoculated and Cym19stop infected p19syn plants. Cym19stop infected wild type plant was sequenced as a control. The sequencing data results supports our claims. An increase in transcriptional levels were found in case of genes known to be under small RNA regulation in uninfected p19syn plants and expressional levels return to normal Cym19stop p19syn plants.
A family of double-homeodomain transcription factors promotes zygotic genome activation in placental mammals [ChIP-seq_d1]
In metazoans, the fertilized embryo is transcriptionally mostly silent for a few cell divisions, until release of a first major wave of embryonic transcripts by so-called zygotic genome activation (ZGA). Maternally provided ZGA-triggering factors have been identified in Drosophila melanogaster and Danio rerio but their mammalian homologues are still undefined. Here, we reveal that DUX family transcription factors are key to this process in human and mouse. First, human Dux4 and murine Dux are expressed prior to ZGA in both species. Second, both orthologues bind to and activate the promoters of ZGA genes. Third, Dux knockdown hinders the progression of mouse embryos beyond the 2-cell stage. Fourth, it prevents the cycling of mouse embryonic stem (ES) cells through a 2-cell-like state whereas, conversely, Dux overexpression induces the accumulation of these ZGA genes-expressing ES cells. We conclude that DUX proteins are master regulators of mammalian ZGA.
SWI/SNF Chromatin-Remodeling Factor Smarcd3/Baf60c Controls Epithelial-Mesenchymal Transition by Inducing Wnt5a Signaling
We previously identified a gene signature predicted to regulate the epithelial-mesenchymal transition (EMT) in both epithelial tissue stem cells and breast cancer cells. A phenotypic RNA interference (RNAi) screen identified the genes within this 140-gene signature that promoted the conversion of mesenchymal epithelial cell adhesion molecule-negative (EpCAM-) breast cancer cells to an epithelial EpCAM+/high phenotype. The screen identified 10 of the 140 genes whose individual knockdown was sufficient to promote EpCAM and E-cadherin expression. Among these 10 genes, RNAi silencing of the SWI/SNF chromatin-remodeling factor Smarcd3/Baf60c in EpCAM- breast cancer cells gave the most robust transition from the mesenchymal to epithelial phenotype. Conversely, expression of Smarcd3/Baf60c in immortalized human mammary epithelial cells induced an EMT. The mesenchymal-like phenotype promoted by Smarcd3/Baf60c expression resulted in gene expression changes in human mammary epithelial cells similar to that of claudin-low triple-negative breast cancer cells. These mammary epithelial cells expressing Smarcd3/Baf60c had upregulated Wnt5a expression. Inhibition of Wnt5a by either RNAi knockdown or blocking antibody reversed Smarcd3/Baf60c-induced EMT. Thus, Smarcd3/Baf60c epigenetically regulates EMT by activating WNT signaling pathways.
Genome-wide occupancy profile of Tbx3, Gata4, Nkx2-5 and p300 in adult mouse whole heart
The contraction pattern of the heart relies on the activation and conduction of the electrical impulse. Perturbations of cardiac conduction have been associated with congenital and acquired arrhythmias as well as cardiac arrest. The pattern of conduction depends on the regulation of heterogeneous gene expression by key transcription factors and transcriptional enhancers. Here, we assessed the genome-wide occupation of conduction system–regulating transcription factors TBX3, NKX2-5, and GATA4 and of enhancer-associated coactivator p300 in the mouse heart, uncovering cardiac enhancers throughout the genome.
Gene Expression Profile of H1299 Cells from Tissue of 4D Model
We have developed a 4D lung cancer model that forms perfusable tumor nodules. We determined if the model could be modified to mimic metastasis. We modified the 4D lung cancer model by seeding H1299 cells via the trachea only to the left lobes of the acellular lung matrix. The model was modified so that the tumor cells can reach the right lobes of the acellular lung matrix only through the pulmonary artery as circulating tumor cells (CTC). We determined the gene expressions of the primary tumor, CTCs, and metastatic lesions using the Human OneArray chip. All cell lines formed a primary tumor in the left lobe of the ex vivo 4D lung cancer model. The CTCs were identified in the media and increased over time. The CTC gene signature predicted poor survival in lung cancer patients. A unique set of genes were significantly expressed in CTC compared to the primary tumor and metastatic lesion. The 4D lung cancer model can isolate tumor cells in three phases of tumor progression. This 4D lung cancer model may mimic the biology of lung cancer metastasis and may be used to determine its mechanism and potential therapy in the future.
Lurbinectedin specifically triggers the degradation of phosphorylated RNA Polymerase II and the formation of DNA breaks in cancer cells
We have defined the mechanism of action of lurbinectedin, a marine-derived drug exhibiting a potent anti-tumorigenic activity across several cancer cell lines and tumor xenografts. This drug currently undergoing clinical evaluation in ovarian, breast and small-cell lung cancer patients inhibits the transcription process through (1) its binding to CG rich sequences, mainly located around the promoter of protein coding genes; (2) the irreversible stalling of elongating RNA polymerase II (Pol II) on the DNA template and its specific degradation by the ubiquitin/proteasome machinery and (3) the generation of DNA breaks. The finding that inhibition of Pol II phosphorylation prevents its degradation and the formation of DNA breaks after drug treatment underscores the connection between transcription elongation and DNA repair. Our results not only help to better understand the high specificity of this drug in cancer therapy but also improve our understanding of an important transcription regulation mechanism.
RNA Maps Reveal New RNA Classes and a Possible Function for Pervasive Transcription
Significant fractions of eukaryotic genomes give rise to RNA, much of which is unannotated and has reduced protein-coding potential. The genomic origins and the relations of human nuclear and cytosolic polyadenylated RNAs longer than 200 nucleotides and whole-cell RNAs less than 200 nt are investigated in this genome-wide study. Subcellular addresses for nucleotides present in detected RNAs were assigned, and their potential processing into short RNAs was investigated. Taken together, these observations suggest a role for some unannotated RNAs as primary transcripts for the production of short RNAs. Three novel potentially functional classes of RNAs have been identified, two of which are syntenically conserved and correlate with the expression state of protein-coding genes. These data support a highly interleaved organization of the human transcriptome. Processed data files: Graph files at ftp://ftp.ncbi.nih.gov/pub/geo/DATA/projects/GSE7576/graphs/ Transfrag files at ftp://ftp.ncbi.nih.gov/pub/geo/DATA/projects/GSE7576/transfrags/ CEL files available on each Sample record tpmap files available on each Platform record Keywords: tiling, RNA population complexity profiling
A family of double-homeodomain transcription factors promotes zygotic genome activation in placental mammals [ChIP-seq_d2]
In metazoans, the fertilized embryo is transcriptionally mostly silent for a few cell divisions, until release of a first major wave of embryonic transcripts by so-called zygotic genome activation (ZGA). Maternally provided ZGA-triggering factors have been identified in Drosophila melanogaster and Danio rerio but their mammalian homologues are still undefined. Here, we reveal that DUX family transcription factors are key to this process in human and mouse. First, human Dux4 and murine Dux are expressed prior to ZGA in both species. Second, both orthologues bind to and activate the promoters of ZGA genes. Third, Dux knockdown hinders the progression of mouse embryos beyond the 2-cell stage. Fourth, it prevents the cycling of mouse embryonic stem (ES) cells through a 2-cell-like state whereas, conversely, Dux overexpression induces the accumulation of these ZGA genes-expressing ES cells. We conclude that DUX proteins are master regulators of mammalian ZGA.
Axiom® Exome 319 Array data to identify susceptible genetic variations of gastric cancer
To efficiently identify genetic susceptibility variants for gastric cancer, including rare coding variants, we performed an exome chip-based array study. We found that a linkage disequilibrium (LD) block containing 2 significant variants in PSCA gene increased the risk and two blocks that included 15 suggested variants including TRIM31, TRIM 40, TRIM 10, and TRIM26 regions, and included one suggested variant and OR2H2 gene showed protective associations with gastric cancer susceptibility. In addition, the PLEC region (rs200893203), FBLN2 region (rs201192415), and EPHA2 region (rs3754334) were associated with increased susceptibility
Comparative Transcriptomic Analysis of Salmonella in Desiccation
To explore the mechanisms of Salmonella desiccation resistance, we studied the transcriptomic responses in Salmonella Tennessee (Tennessee), using S. Typhimurium LT2 (LT2), a strain weakly resistant to desiccation, as a reference strain. In response to 2 h air-drying at 11% equilibrated relative humidity, approximately one-fourth of the ORFs in the Tennessee genome and one-fifth in LT2 were differentially expressed (> 2-fold). Among all differentially expressed functional groups (>5-fold) in both strains, the expression fold change associated with fatty acid metabolism was the highest, and constituted 51 and 35% of the total expression fold change in Tennessee and LT2, respectively. Tennessee showed greater changes in expression of genes associated with stress response and envelope modification than LT2, while showing lesser changes in protein biosynthesis expression. Expression of flagella genes was significantly more inhibited in stationary phase cells of Tennessee than LT2 both before and after desiccation.
Spliced synthetic genes as internal controls in RNA sequencing experiments.
RNA sequencing (RNA-seq) can be used to assemble spliced isoforms, quantify expressed genes and provide a global profile of the transcriptome. However, the size and diversity of the transcriptome, the wide dynamic range in gene expression and inherent technical biases confound RNA-seq analysis. We have developed a set of spike-in RNA standards, termed ‘sequins’ (sequencing spike-ins), that represent full-length spliced mRNA isoforms. Sequins have an entirely artificial sequence with no homology to natural reference genomes, but align to gene loci encoded on an artificial in silico chromosome. The combination of multiple sequins across a range of concentrations emulates alternative splicing and differential gene expression, and provides scaling factors for normalization between samples. We demonstrate the use of sequins in RNA-seq experiments to measure sample-specific biases and determine the limits of reliable transcript assembly and quantification in accompanying human RNA samples. In addition, we have designed a complementary set of sequins that represent fusion genes arising from rearrangements of the in silico chromosome to aid in cancer diagnosis. RNA sequins provide a qualitative and quantitative reference with which to navigate the complexity of the human transcriptome.
A family of double-homeodomain transcription factors promotes zygotic genome activation in placental mammals [RNA-seq]
In metazoans, the fertilized embryo is transcriptionally mostly silent for a few cell divisions, until release of a first major wave of embryonic transcripts by so-called zygotic genome activation (ZGA). Maternally provided ZGA-triggering factors have been identified in Drosophila melanogaster and Danio rerio but their mammalian homologues are still undefined. Here, we reveal that DUX family transcription factors are key to this process in human and mouse. First, human Dux4 and murine Dux are expressed prior to ZGA in both species. Second, both orthologues bind to and activate the promoters of ZGA genes. Third, Dux knockdown hinders the progression of mouse embryos beyond the 2-cell stage. Fourth, it prevents the cycling of mouse embryonic stem (ES) cells through a 2-cell-like state whereas, conversely, Dux overexpression induces the accumulation of these ZGA genes-expressing ES cells. We conclude that DUX proteins are master regulators of mammalian ZGA.
Epigenetic therapy as a novel approach for GFI136N-associated AML
Acute myeloid leukemia (AML) is characterized by accumulation of myeloid blast cells in the bone marrow. Despite all efforts, prognosis of AML patients remains poor, warranting new therapeutic approaches. A single nucleotide polymorphism of growth factor independence 1 (GFI1), a hematopoietic transcription factor, generates a protein with an asparagine (GFI136N) instead of a serine at position 36 (GFI136S), which we have previously reported to be associated with de novo AML in humans. Using knock-in mouse strains, in which the endogenous murine Gfi1 coding sequences are substituted by human GFI136N or GFI136S, we found that GFI136N shortened latency and increased incidence of AML in three different, well-established murine models of AML. On a molecular level, the presence of GFI136N was associated with increased acetylation of histone H3 at lysine 9 (H3K9) at Gfi1 target genes in both murine and human samples, contributing to AML development. Since in GFI136N containing leukemic cells Gfi1 target genes have hyperacetylated H3K9, the treatment strategy currently used with histone deacetylases inhibitors (HDACis) might not be beneficial. We show that treatment with an HDACi impeded growth of murine and human cells homozygous for GFI136S, but had a limited effect on cells expressing GFI136N. In contrast, treatment with a histone acetyltransferase inhibitor (HATi) specifically targeted GFI136N-expressing malignant cells while sparing non-malignant cells. These results establish, as a proof of principle, how epigenetic changes in GFI136N-induced AML can be exploited to treat AML and implicate HATi as a new, more effective potential therapeutic strategy for GFI136N AML patients.
Genome-wide distribution of 5-formylcytosine in ES cells is associated with transcription and depends on TDG
Methylation of cytosine in DNA (5mC) is an important epigenetic mark that is involved in the regulation of genome function. During early embryonic development in mammals, the DNA methylation landscape is dynamically reprogrammed in part through active demethylation. Recent advances have identified key players involved in active demethylation pathways, including oxidation of 5mC to 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) by the TET family of enzymes and excision of 5fC by the base excision repair enzyme thymine DNA glycosylase (TDG). Here, we provide the first genome-wide distribution map of 5fC in mouse embryonic stem (ES) cells and evaluate potential roles for 5fC in differentiation. Our method exploits the unique reactivity of 5fC to link a biotin tag for pulldown and high-throughput sequencing. Genome-wide mapping revealed 5fC enrichment in CpG islands (CGIs) of promoters and exons. CGI promoters in which 5fC was relatively more enriched than 5mC or 5hmC corresponded to transcriptionally active genes. Accordingly, 5fC-rich promoters had elevated H3K4me3 levels, a histone mark associated with active transcription, and were frequently bound by RNA Polymerase II. Downregulation of TDG led to accumulation of 5fC in CGIs in ES cells, which correlates with increased methylation in these genomic regions during differentiation and in mouse embryonic fibroblasts derived from TDG knockout embryos. Collectively, our data suggest that 5fC plays a role in epigenetic reprogramming. The formation and removal of this cytosine modification are confined to specific genomic regions, which are in part controlled by TDG. Notably, 5fC excision in ES cells is necessary for the correct establishment of CGI methylation patterns during differentiation, and hence, for appropriate patterns of gene expression during development.
High- and low-affinity cre boxes for CcpA binding in Bacillus subtilis revealed by genome-wide analysis
In Bacillus subtilis and its relatives carbon catabolite control, a mechanism enabling to reach maximal efficiency of carbon and energy sources metabolism, is achieved by the global regulator CcpA (carbon catabolite protein A). CcpA in a complex with HPr-Ser-P (seryl-phosphorylated form of histidine-containing protein, HPr) binds to operator sites called catabolite responsive elements, cre. Depending on the cre box position relative to the promoter, the CcpA/HPr-Ser-P complex can either act as a positive or a negative regulator. The cre boxes are highly degenerate semi-palindromes with a lowly conserved consensus sequence. So far, studies aimed at revealing how CcpA can bind such diverse sites were focused on the analysis of single cre boxes. In this study, a genome-wide analysis of cre sites was performed in order to identify differences in cre sequence and position, which determine their binding affinity. The transcriptomes of B. subtilis cultures with three different CcpA expression levels were compared. The higher the amount of CcpA in the cells, the more operons possessing cre sites were differentially regulated. The cre boxes that mediated regulation at low CcpA levels were designated as strong (high affinity) and those which responded only to high amounts of CcpA, as weak (low affinity). Differences in the sequence and position in relation to the transcription start site between strong and weak cre boxes were revealed. Certain residues at specific positions in the cre box as well as, to a certain extent, a more palindromic nature of cre sequences and the location of cre in close vicinity to the transcription start site contribute to the strength of CcpA-dependent regulation. The main factors contributing to cre regulatory efficiencies, enabling subtle differential control of various subregulons of the CcpA regulon, are identified.
Chronic signaling via the metabolic checkpoint kinase mTORC1 induces macrophage granuloma formation and marks sarcoidosis progression
Gene expression analysis of primary CSF1-deprived bone marrow-derived macrophages (BMDM) of Tsc2fl/fl LysM+/+ and TSC2fl/fl LysM+/cre mice Maintenance of tissue homeostasis requires a tight control of the in situ-proliferative capacity of tissue-resident macrophages. Here we show that specific deletion of Tsc2 in myeloid cells breaks quiescence and strongly induces macrophage proliferation and hypertrophy leading to granuloma formation in vivo in an mTORC1-dependent manner. Intriguingly, the growth factor CSF1 induces expression of cyclin-dependent kinase 4 (CDK4) via TSC2-mTORC1 to stimulate cell proliferation, while simultaneously NF-κB signaling and apoptosis are inhibited. Tsc2-deficient macrophages show constitutive CDK4 expression and enhanced M2-like polarization that is supported by a metabolic reprogramming towards increased glycolysis and mitochondrial metabolism. Strikingly, mTORC1 activation and macrophage proliferation are identified as a hallmark of the human granulomatous disease sarcoidosis and correlate with a clinically progressive disease outcome. In conclusion, TSC2-mTORC1 integrates macrophage quiescence, polarization, and metabolism to prevent granulomatous disease. Fundamentally, we show that the macrophage cell cycle is controlled by a growth factor-induced expression of CDK4.
Comprehensive evaluation of genome-wide 5-hydroxymethylcytosine profiling approaches in human DNA [HumanMethylation450]
The gold standard bisulphite conversion technologies to study DNA methylation do not distinguish between 5mC and 5hmC, however new approaches to map 5hmC genome-wide have advanced rapidly, although it is unclear how the different methods compare in accurately calling 5hmC. In this study, we provide a comparative analysis on brain DNA using three 5hmC genome-wide approaches; namely whole-genome bisulphite/oxidative-bisulphite sequencing (WG Bis/OxBis-seq), Infinium HumanMethylation450 BeadChip arrays coupled with oxidative bisulphite (HM450K Bis/OxBis) and antibody-based immunoprecipitation and sequencing of hydroxymethylated DNA (hMeDIP-seq). We also compare the performance of these approaches in adult brain DNA, with a known high abundance of 5hmC, and cancer cell line LNCaP DNA, with cell lines known to have low levels of 5hmC.
Effects of Disperse Yellow 7 in Silurana tropicalis Gene Network Analysis
Dyes used in fabric and leather industry are being released and accumulated into Canadian ecosystems. Recent studies have demonstrated that dyes made of azo compounds significantly increase toxicity in biota, which is explained by their toxic metabolites (e.g., aromatic amines). The metabolites of azo compounds interact with hydrophobic surfaces of cell membranes causing expansion of the membrane which impede normal cellular functions. It has been suggested that this process leads to cell death due to improper ion balance. Currently, it is estimated that between 10 and 15% of azo dyes are released in the environment as effluent. The aim of this study was to evaluate toxicity and gene networks altered by azo compounds in amphibians using ecotoxicogenomic approaches. Larvae of the frog Silurana tropicalis (Western clawed frog) were exposed to sediment contaminated to 887 ppm Disperse Yellow 7 (DY7). Larvae were exposed from Nieuwkoop-Faber developmental stage 12 to 46. Data suggest that the azo dye DY7 induced cellular stress and interfered with androgen biosynthesis in early tadpole development. At exposure completion, RNA was isolated from whole larvae and quality was ascertained using bioanalyzer analysis. A custom Agilent 4 X 44 K microarray for S. tropicalis was used to characterize gene regulatory networks underlying toxicity. This study presents the transcriptional regulatory pathways affected by DY7 in S. tropicalis early development.
Nucleotide resolution analysis reveals extensive regulation of translation in response to neural depolarization.
Studies on regulation of gene expression have contributed substantially to understanding mechanisms for long term alterations in neural connectivity in response to activity. Most of these, however, focused on the regulation of mRNA transcription. Here, we utilized high-throughput sequencing coupled with ribosomal footprinting to globally characterize the regulation of translation in neural cells in response to depolarization-mediated neural activity. We identify substantial and complex regulation of translation, with hundreds of transcripts demonstrating changes in ribosome occupancy independent of transcriptional changes. These changes are partially mediated by features in the sequence —notably uAUGs and secondary structure in the 5’UTR— both of which predict downregulation in response to activity. These transcripts are also disproportionately targets of Fmrp and include genes implicated in autism in humans. Our findings indicate that in neurons activity plays a critical role in regulating mRNA translation across the genome and suggest dysregulation of the process may contribute to disease.
The redox-sensitive regulatory module of cyclophilin 20-3, 2-cysteine peroxiredoxin and cysteine synthase in the high light acclimation response in Arabidopsis thaliana
Previous data suggest that 2-cysteine peroxiredoxin, cyclophilin 20-3 and the cysteine synthase complex work as a dynamically interacting module (here named COPS-module) and are involved in stress response. In this study we performed global transcriptome analyses to investigate the responses to short-term high light in wildtype and mutants deficient in each protein of COPS-module. The global transcriptomic response in leaves to 6 h high light in Col.0 and mutants deficient in each protein of COPS-module.
Piwi negatively regulates Polycomb Group proteins in maintaining germline stem cells and oogenesis
Piwi regulates niche and intrinsic mechanisms to maintain germline stem cells in Drosophila, yet how this regulation occurs remains elusive. Here, we show that Piwi interacts with the Polycomb Group Complexes PRC1 and PRC2 to maintain ovarian germline stem cells and oogenesis, as well as to repress retrotransposons. Piwi binds to PRC2 subunits Su(z)12 and Esc in vitro and forms a complex with PRC2 in vivo. Whole-genome analyses of PRC2-mediated histone 3 lysine 27 trimethylation (H3K27m3) in wild type and piwi mutant ovarian nuclei indicate that Piwi inhibits H3K27m3 at PRC2 target genes that are mostly regulators of development and transcription.
Conserved Topological Domains in Mammalian Genomes Identified by High-resolution Analysis of Chromatin Interactions
The spatial organization of the genome is intimately linked to its biological function, yet our understanding of higher order genomic structure is limited. Here we present high-resolution analyses of chromosomal organization in pluripotent and differentiated human and murine cell types determined using the Hi-C technique. We find that the mammalian genome is composed of over 1000 topological domains, which are stable among different cell types and highly conserved across species. These megabase-long genomic structures, defined by prominent local chromatin interactions and separated by narrow boundary regions, likely function to restrict regulatory interactions between cis-acting elements and limit the spreading of heterochromatin during cellular differentiation. Interestingly, the boundaries are enriched not only for binding sites of the insulator protein CTCF, but also for promoters of house keeping genes, supporting a role for both CTCF and housekeeping genes in the establishment or maintenance of the topological domains.
Control of progenitor cell positioning and organ patterning during embryogenesis
The precise positioning of organ progenitor cells constitutes an essential, yet poorly understood step in organ development and function. Using primordial germ cells and the process of gonadogenesis as an in vivo model, we present the developmental mechanisms facilitating the maintenance of a motile progenitor cell population at the site where the organ develops. We find that the action of repulsive cues coupled with the generation of physical barriers confine the cells to the correct bilateral positions within the embryo. Using computer particle-based simulations we could also demonstrate the role of reflecting barriers, from which cells turn away upon contact, and the importance of proper level of cell-cell interaction for maintaining the tight cell clusters and their correct positioning at the target region. The cellular mechanisms operating during those events were determined using high-resolution live imaging microscopy. This analysis revealed cell polarity change upon interaction with the physical barrier and the establishment of compact clusters that involves increased cell-cell interaction as a result of collapse of cell protrusions and enhanced adhesion. The combination of these developmental and cellular
DNA methylation status of the liver of MAT1A WT and MAT1A KO mice treated with placebo or SAMe during 8 weeks
Methionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
Neuroblastoma cells depend on HDAC11 for mitotic cell cycle progression and survival
The number of long-term survivors of high-risk neuroblastoma remains discouraging, with 10-year survival as low as 20%, despite decades of considerable international efforts to improve outcome. Major obstacles remain and include managing resistance to induction therapy, which causes tumor progression and early death in high-risk patients, and managing chemotherapy-resistant relapses, which can occur years after the initial diagnosis. Identifying and validating novel therapeutic targets is essential to improve treatment. Delineating and deciphering specific functions of single histone deacetylases in neuroblastoma may support development of targeted acetylome-modifying therapeutics for patients with molecularly defined high-risk neuroblastoma profiles. We show here that HDAC11 depletion in MYCN-driven neuroblastoma cell lines strongly induces cell death, mostly mediated by apoptotic programs. Genes necessary for mitotic cell cycle progression and cell division were most prominently enriched in at least two of three time points in whole-genome expression data combined from two cell systems, and all nine genes in these functional categories were strongly repressed, including CENPA, KIF14, KIF23 and RACGAP1. Enforced expression of one selected candidate, RACGAP1, partially rescued the induction of apoptosis caused by HDAC11 depletion. High-level expression of all nine genes in primary neuroblastomas significantly correlated with unfavorable overall and event-free survival in patients, suggesting a role in mediating the more aggressive biological and clinical phenotype of these tumors. Our study identified a group of cell cycle-promoting genes regulated by HDAC11, being both predictors of unfavorable patient outcome and essential for tumor cell viability. The data indicates a significant role of HDAC11 for mitotic cell cycle progression and survival of MYCN-amplified neuroblastoma cells, and suggests that HDAC11 could be a valuable drug target.
The N-glycosylated isoform of β-integrin as a potential biomarker and target in HER-2+ BC refractory to HER-2 targeted therapies.
Acquired resistance to trastuzumab, a rationally designed HER-2 targeting antibody, remains a major hurdle in management of HER-2 positive breast cancer (HER-2+ BC) patients. Potential resistance mechanisms are numerous, derived primarily from studies where HER-2 positive cell lines are chronically exposed to trastuzumab. Recent evidence suggests a role for epithelial-mesenchymal transition (EMT) in trastuzumab resistance, but a definitive link between the two has been difficult to establish because relevant model systems are lacking. When sub-populations of trastuzumab sensitive SKBR-3 cells were isolated using cloning rings, an (EMT) occurred spontaneously in several (3/8) clones. SKBR-3 EMT-clones featured increased spindle morphology, expressed N-glycosylated β1-integrin, and decreased HER-2, all characteristics shared by JIMT-1, a cell lines with intrinsic resistance to trastuzumab. SKBR-3 EMT-clones were characterized by gene expression profiling and mammosphere formation. The N-glycosylated isoform of β-itnegrin was targeted with β-integrin inhibiting antibody, AIIB2. Transcriptional profiling revealed that SKBR-3 EMT-clones underwent a shift from a luminal molecular subtype to a more aggressive mesenchymal/ basal phenotype. Isolating clones from SKBR-3 cells with enforced expression of a β-integrin isoform lacking extensive N-glycosylation failed to increase the likelihood for spontaneous EMT in SKBR-3. However, specific inhibition of the heavily N-glycosylated variant of β1-integrin expressed by SKBR-3 EMT-clones restored epithelial morphology and impaired mammosphere formation. Furthermore, when SKBR-3 EMT-clones were treated with relevant doses of trastuzumab and lapatinib, they showed “spontaneous” resistance. In this study we describe a model of spontaneous EMT following clonal selection in HER-2+ cell line, SKBR-3. Using this model we establish the first direct link between EMT and resistance to HER-2 targeted therapies. We also identify the N-glycosylated isoform of β-integrin as a potential biomarker and target in HER-2+ BC refractory to HER-2 targeted therapies.
Natural variation in the yeast glucose-signaling network reveals a new role for the Mig3p transcription factor
The Crabtree effect, in which fermentative metabolism is preferred at the expense of respiration, is a hallmark of budding yeast’s glucose response and a model for the Warburg effect in human tumors. While the glucose-responsive transcriptional repressors Mig1p and Mig2p play well-characterized roles in the Crabtree effect, little function for the related Mig3p transcription factor has been uncovered despite numerous investigations of laboratory yeast strains. Here we studied a wild isolate of Saccharomyces cerevisiae to uncover a critical role for Mig3p that has been lost in S288c-derived laboratory strains. We found that Mig3p affects the expression of hundreds of glucose-responsive genes in the oak strain YPS163, both during growth under standard conditions and upon ethanol treatment. Our results suggest that Mig3p may act as a multifunctional activator/repressor that plays separate roles under standard versus stress conditions, but this function has been largely lost in the lab strains. Population analysis suggests that the lab strain, and several wild strains, harbor mutations that diminish Mig3p function. Thus, by expanding our attention to multiple genetic backgrounds, we have uncovered an important missing link in a key metabolic response.
Gene expression analysis of the liver of MAT1A WT and MAT1A KO mice treated with placebo or SAMe during 8 weeks
Methionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
RNA Seq analysis of e12.5 mouse pancreatic buds from control and Pdxcre; Gata4fl/fl;Gata6fl/fl; Tom mice
about 250 genes were significantly changed after Gata4 and Gata6 were specifically deleted in the pancreatic progenitor cells 6 pancreatic buds were pooled for the control, and 12 pancreatic buds were pooled for the Pdxcre; Gata4fl/fl; Gata6fl/fl. Libraries were prepared from total RNA (RIN>8) with the TruSeq RNA prep kit (Illumina) and sequenced using the HiSeq2000 (Illumina) instrument. More than 20 million reads were mapped to the mouse genome (UCSC/mm9) using Tophat (version 2.0.4) with 4 mismatches and 10 maximum multiple hits. Significantly differentially expressed genes were calculated using DEseq
Expression data from RUNX1(41-214)-expressing and Runx1-knockout mice KSL cells
Mutations of RUNX1 are detected in patients with myelodysplastic syndrome (MDS). In particular, C-terminal truncation mutations lack a transcription regulatory domain and have increased DNA binding through the runt homology domain (RHD). The expression of the RHD, RUNX1(41-214), in mouse hematopoietic cells induced progression to MDS and acute myeloid leukemia (AML). Analysis of pre-myelodysplastic animals revealed expansion of c-Kit+Sca-1+Lin- (KSL) cells and skewed differentiation to myeloid at the expense of the lymphoid lineage. These abnormalities correlate with the phenotype of Runx1-deficient animals, as expected given the reported dominant-negative role of C-terminal mutations over the full-length RUNX1. However, MDS is not observed in Runx1-deficient animals. Gene expression profiling revealed that RUNX1(41-214) KSLs have an overlapping yet distinct gene expression profile from Runx1-deficient animals. Moreover, an unexpected parallel was observed between the hematopoietic phenotype of RUNX1(41-214) and aged animals. Genes deregulated in RUNX1(41-214), but not in Runx1-deficient animals, were inversely correlated with the aging gene signature of hematopoietic stem cells (HSC), suggesting that disruption of the expression of genes related to normal aging by RUNX1 mutations contributes to development of MDS. The data presented here provide insights into the mechanisms of development of MDS in HSCs by C-terminal mutations of RUNX1. Gene expression analysis were performed on c-Kit+/Sca-1+/Lin-/IL7Ra- (KSL) cells sorted from RUNX1(41-214)-expressing and Runx1-knockout (Runx1floxed/floxed MxCre+/-) and control mice (Runx1floxed/floxedMxCre-/-).
Transcript atlases reveal that artery tertiary lymphoid organs but not secondary lymphoid organs control key steps of atherosclerosis T cell immunity in aged apoe-/- mice.
Tertiary lymphoid organs (TLOs) emerge in response to nonresolving inflammation but their roles in adaptive immunity remain unknown. Here, we explored artery TLOs (ATLOs) to delineate atherosclerosis T cell responses in apoe-/- mice during aging. Though the T cell repertoire showed systemic age-associated contractions in size and modifications in subtype composition and activation, wt and apoe-/- mice were equally affected. In contrast, ATLOs - but not wt aortae, apoe-/- aorta segments without ATLOs or atherosclerotic plaques - promoted T cell recruitment, altered characteristics of T cell motility, primed and imprinted T cells in situ, generated CD4+/FoxP3-, CD4+/FoxP3+, CD8+/FoxP3- effector and central memory cells, and converted naïve CD4+/FoxP3- T cells into induced Treg cells. ATLOs also showed substantially increased antigen presentation capability by conventional dendritic cells (DCs) and monocyte-derived DCs but not by plasmacytoid DCs. Thus, the senescent immune system specifically employs ATLOs to control dichotomic atherosclerosis T cell immune responses. We assembled transcriptome maps of wt and apoe-/- aortae and aorta-draining RLNs and identified ATLOs as major sites of atherosclerosis-specific T cell responses during aging: Transcriptome atlases of wt and apoe-/- abdominal aortae and associated draining RLNs were constructed from laser capture microdissection (LCM)-based whole genome mRNA expression microarrays yielding 6 maps: wt adventitia (tissue-1); wt RLN (tissue-2); apoe-/- ATLOs (tissue-3); apoe-/- RLN (tissue-4); apoe-/- adventitia without adjacent plaques (tissue-5), and plaques (tissue-6). Several two-tissue comparisons within the transcriptome atlases are noteworthy: Unexpectedly, transcriptomes of wt and apoe-/- RLNs were virtually identical; additonal data revealed that transcriptomes of RLNs were strikingly similar to those of inguinal LNs which do not drain the aorta adventitia (as shown of India ink injection experiments of surgically exposed aortae); in sharp contrast, wt adventitia versus ATLOs revealed 1405 differentially expressed transcripts many of which encoded members of GO terms immune response and inflammatory response; the ATLO-plaque comparison also showed > 1000 differentially expressed transcripts; however, wt adventitia versus apoe-/- adventitia without plaque showed few genes (< 5 % of differentially expressed transcripts of the wt adventitia-ATLO comparison). Thus, the aorta transcriptome atlases support the conclusion that neither aorta-draining apoe-/- RLNs nor ILNs participate in atherosclerosis-specific T cell responses. In addition, they demonstrate that T cell responses in the diseased aorta are highly territorialized. Finally, these data show that the immune responses carried out in ATLOs differ significantly from those carried out in plaques. We next identified three major clusters within the transcriptome atlases through ANOVA analyses and application of strict filters: An adventitia cluster, a plaque/ATLO cluster, and a LN/plaque cluster. The total number of differentially expressed genes in each cluster were examined for GO terms immune response, inflammatory response, T cell activation, positive regulation of T cell response, and T cell proliferation. Within the adventitia cluster, similarities of transcriptomes of wt adventitia and apoe-/- adventitia without associated plaque versus ATLOs indicate that a robust number of immune response-regulating genes are selectively expressed in ATLOs which are located within a distance of few µm of the adventitia without associated plaques indicating a very high degree of territoriality of the atherosclerosis T cell response. Furthermore, unlike the total number of differentially regulated transcripts, the majority of transcripts among GO terms immune response and inflammatory response, was up-regulated. Inspection of the plaque/ATLO cluster provided further information: The majority of immune response regulating genes where expressed at a higher level in ATLOs when compared to plaques though plaques also contained a significant number of immune response regulating genes; the reverse is true for genes regulating inflammation. Finally, the lymph node cluster revealed that though the majority of immune response regulating genes resides in both wt and apoe-/- RLNs (with little differences between them) ATLOs express a selected set of immune response regulating genes at a higher level when compared to LNs. In addition, the inflammatory component of ATLOs when compared to LNs is documented by the finding that many more genes regulating inflammation reside in ATLOs even when compared to those of plaques. Key words: T cell response in atherosclerosis; Laser capture microdissection; transcriptome atlas of atherosclerosis. Citations: Gräbner R. et al. Lymphotoxin beta receptor signaling promotes tertiary lymphoid organogenesis in the aorta adventitia of aged ApoE-/- mice. J Exp Med 2009 Jan 16;206(1):233-48. PMID: 19139167; Moos M. et al. The lamina adventitia is the major site of immune cell accumulation in standard chow-fed apolipoprotein E-deficient mice. Arterioscler Thromb Vasc Biol. 2005 Nov;25(11):2386-91. Epub 2005 Sep 22. PMID: 16179593; Beer M. et al. Laser-capture microdissection of hyperlipidemic/ApoE-/- mouse aorta atherosclerosis. Methods Mol Biol. 2011;755:417-28. PMID: 21761324; Weih F. et al. Control of Dichotomic Innate and Adaptive Immune Responses by Artery Tertiary Lymphoid Organs in Atherosclerosis. Front Physiol. 2012;3:226. Epub 2012 Jul 6. PMID: 22783198.
Deep RNA sequencing of the human placental transcriptome
The goal of this study was to conduct an in-depth analysis of the human placental transcriptome. RNA was extracted from 16 placental samples using TRIzol following the manufacturer’s protocol. All samples were spiked with 96 External RNA Controls Consortium (ERCC) ExFold RNA transcripts. Ribosomal RNAs were depleted from samples using Ribo-Zero Gold and sequencing libraries were prepared using Illumina TruSeq Stranded Total RNA Sample Preparation kits. Sequencing was performed on the Illumina Hi-Seq 2500 using a 100bp paired-end protocol. Sequence adapters were trimmed using AdapterRemoval with options --trimns, --minlength 20. Trimmed RNA-Seq reads were aligned to known UCSC hg19 genes and the hg19 genome using Bowtie 2 v2.1.0 and TopHat v2.0.9 with options --library-type=fr-firststrand --mate-inner-dist -20 --mate-std-dev 180. UCSC hg19 reference genome and transcriptome was obtained through Illumina iGenomes (https://support.illumina.com/sequencing/sequencing_software/igenome.html). Aligned RNA-Seq reads were summarised using the summarizeOverlaps algorithm with the UCSC known genes hg19 GTF file using the the options overlapMode=``Union'', ignoreStrand=FALSE, singleEnd=FALSE, fragments=TRUE to generate a table of unique read counts per gene for each sample. All samples were processed in the same way, with all sequencing libraries created in the same batch and sequenced together.
Hepatocyte-like cells
Hepatocyte-like cells (HLCs) are derived from human pluripotent stem cells (hPSCs) in vitro, but differentiation protocols commonly give rise to a heterogeneous mixture of cells. This variability confounds the evaluation of in vitro functional assays performed using HLCs. We demonstrate the purification of a sub-population of functional HLCs differentiated from multiple hPSC lines using the hepatocyte surface marker Asialoglycoprotein Receptor 1 (ASGR1). We analyzed the expression profile of ASGR1-positive cells by microarray, and tested their ability to perform mature hepatocyte functions (albumin and urea secretion, cytochrome activity). By these measures, ASGR1-positive HLCs are enriched for the gene expression profile and functional characteristics of primary hepatocytes compared to unsorted HLCs.
Nasopharyngeal microbiota, host transcriptome and disease severity in children with respiratory syncytial virus infection
Rationale: Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and hospitalizations in infants worldwide. Known risk factors, however, incompletely explain the variability of RSV disease severity among children. We postulate that severity of RSV infection is influenced in part by modulation of the host immune response by the local microbial ecosystem at the time of infection. Objectives: To define whether different nasopharyngeal microbiota profiles are associated with distinct host transcriptome profiles and severity in children with RSV infection. Methods: We analyzed the nasopharyngeal microbiota profiles of young children with mild and severe RSV disease and healthy matched controls by 16S-rRNA sequencing. In parallel, we analyzed whole blood gene expression profiles to study the relationship between microbial community composition, the RSV-induced host transcriptional response and clinical disease severity. Measurements and Main results: We identified five nasopharyngeal microbiota profiles characterized by enrichment of H. influenzae, Streptococcus, Corynebacterium, Moraxella or S. aureus. RSV infection and RSV hospitalization were positively associated with H. influenzae and Streptococcus, and negatively associated with S. aureus abundance, independent of age. The host response to RSV was defined by overexpression of interferon-related genes, and this was independent of the microbiota composition. On the other hand, transcriptome profiles of RSV infected children with H. influenzae and Streptococcus-dominated microbiota were characterized by greater overexpression of genes linked to toll-like receptor-signaling and neutrophil activation and were more frequently hospitalized Conclusions: Our data suggest an immunomodulatory role for the resident nasopharyngeal microbial community early in RSV infection, potentially affecting RSV disease severity.
5-hmC in the brain: abundance in synaptic genes and differences at the exon-intron boundary (MRE-Seq)
5-hydroxymethylcytosine (5-hmC), a derivative of 5-methylcytosine (5-mC), is abundant in the brain for unknown reasons. We mapped the genomic distribution of 5-hmC and 5-mC in human and mouse tissues using glucosylation of 5-hmC coupled with restriction enzyme digestion, and interrogation on microarrays. We detected 5-hmC enrichment in genes with synapse-related functions in the brain. We also identified significant, tissue-specific differential distributions of these DNA modifications at the exon-intron boundary, in both human and mouse. This boundary change was mainly due to 5-hmC in the brain, but due to 5-mC in non-neural contexts. This pattern was replicated in multiple independent datasets, and the brain-specific change in 5-hmC was validated using single-molecule sequencing. Moreover, in the brain, constitutive exons contained higher levels of 5-hmC, relative to alternatively-spliced exons. Our study suggests a novel role for 5-hmC in RNA splicing and synaptic function in the brain
Time course RNA-Seq of Innate Lymphoid Cells in Early Acute HIV Infection
We apply RNA-seq to limited populations of Innate Lymphoid Cells type 2 and type 3 (ILC2s and ILC3s, respectively) in human individuals infected with acute HIV in the FRESH study. We measured the whole transcriptome of ILC2s and ILC3s in both untreated (n=2) and ART treated (n=2) individuals over the course of infection, in order to compare these populations at key points during infection, namely: viral detection, peak viremia, and weeks past peak viremia (6-7 weeks post detection). Lacking true biological replicates, HIV- patients in the same study (n=9) were used as replicates to conduct Differential Expression (DE) analysis between time points in both ILC2s and ILC3s on a patient by patient basis. In untreated patients, ILC2s and ILC3s differentially expressed genes associated with apoptosis and cell death between peak viremia and viral detection, while ART treated patients' ILC2s and ILC3s demonstrated a mitigated response. Comparing 6-7 weeks after detection with peak viremia revealed a relative decrease in genes associated in cell death in untreated patients, while ART treated patients showed varied responses where several DE genes were associated with immune response.
Analyzing primary Hodgkin and Reed-Sternberg cells to capture the molecular and cellular pathogenesis of classical Hodgkin lymphoma
The pathogenesis of classical Hodgkin lymphoma (cHL), the most common lymphoma in the young, is still enigmatic, largely because its Hodgkin and Reed-Sternberg (HRS) tumor cells are rare in the involved lymph node and therefore difficult to analyze. Here, by overcoming this technical challenge and performing for the first time a genome-wide transcriptional analysis of microdissected HRS cells in comparison to other B-cell lymphomas, cHL lines and normal B-cell subsets, we show that they differ extensively from the usually studied cHL cell lines, that the lost B-cell identity of cHLs is not linked to the acquisition of a plasma cell-like gene expression program, and that Epstein-Barr virus infection of HRS cells has a minor transcriptional influence on the established cHL clone. Moreover, although cHL appears a distinct lymphoma entity overall, HRS cells of its histological subtypes diverged in their similarity to other related lymphomas. Unexpectedly, we identified two molecular subgroups of cHL associated to differential strengths of the transcription factor activity of the NOTCH1, MYC and IRF4 proto-oncogenes. Finally, HRS cells display deregulated expression of several genes potentially highly relevant to lymphoma pathogenesis, including silencing of the apoptosis-inducer BIK and of INPP5D, an inhibitor of the PI3K-driven oncogenic pathway.
Pol II docking and pausing at growth and stress genes in C. elegans
Fluctuations in nutrient availability profoundly impact gene expression. Previous work revealed post-recruitment regulation of RNA Polymerase II (Pol II) during starvation and recovery in Caenorhabitis elegans, suggesting promoter-proximal pausing promotes rapid response to feeding. To test this hypothesis, we measured Pol II elongation genome-wide by two complementary approaches and analyzed elongation in conjunction with Pol II binding and expression. We confirmed bona fide pausing during starvation and also discovered Pol II docking. Pausing occurs at active stress-response genes that become down-regulated in response to feeding. In contrast “docked” Pol II accumulates without initiating upstream of inactive growth genes that become rapidly up-regulated upon feeding. Beyond differences in function and expression, these two sets of genes have different core promoter motifs, suggesting alternative transcriptional machinery. Our work suggests that growth and stress genes are both regulated post-recruitment during starvation, but at initiation and elongation, respectively, coordinating gene expression with nutrient availability.
Transcriptome sequencing of GRK6 knockout HSCs and CLPs
WT and GRK6-/- Lin-c-kit+sca-1+ cells (hereafter referred to as HSC) as well as CLP (Lin-c-kit+sca-1+Il-7Ra+) with pooled cDNA library of 13-15 sorted and individually amplified cells from 3-4 mice were sequenced.
Transcriptome sequencing of Prunus mume for different tissues.
We have sequenced a wild Prunus mume and constructed a reference sequence for this genome. In order to improve quality of gene models, RNA samples of five tissues (bud, leaf, root, stem, fruit) were extracted from the Prunus mume. To investigate tissue specific expression using the reference genome assembly and annotated genes, we extracted RNA samples of different tissues and conducted transcriptome sequencing and DEG analysis.
Polyunsaturated dietary fats decrease mortality and bacterial load during septic S. aureus infection, and improve neutrophil function in mice
Severe infections and sepsis is an increasing clinical problem that cause prolonged morbidity and substantial mortality. At present, antibiotics are essentially the only pharmacological treatment for sepsis. The incidence of antibiotic resistance is increasing and it is therefore critical to find new therapies for sepsis. Staphylococcus aureus (S. aureus) is a major cause of septic mortality. Neutrophils play a major role in defense against bacterial infections. We have recently shown that a saturated high fat diet decreases survival in septic mice, but the mechanisms behind remain elusive. The aim of the present study was to investigate how the dietary fat composition affects survival and neutrophils function after experimental septic infection in mice. We found that, after S. aureus infection, mice fed polyunsaturated high fat diet (HFD/P) for 8 weeks had increased septic survival and decreased bacterial load compared with mice fed saturated HFD (HFD/S), and similar to that of mice given low fat diet (LFD). Furthermore, uninfected mice fed HFD/P had increased number of Ly6G+ neutrophils in bone marrow. In addition, mice fed HFD/P had a higher number Ly6G+ neutrophils recruited to the site of inflammation after peritoneal injection of thioglycollate. In conclusion, polyunsaturated dietary fat increased both survival and the efficiency of the bacterial clearance during septic S. aureus infection. Moreover, this diet enhanced the number and chemotaxis of neutrophils, a key component of the immune response to S. aureus infections.
miR-146a Exerts Differential Effects on Melanoma Growth and Metastatization.
Malignant melanoma is the most aggressive form of skin cancer therefore it is crucial to disclose its underlying molecular mechanisms. MicroRNAs are small endogenous non-coding RNAs able to post-transcriptionally down-regulate the expression of direct target genes. Using a melanoma progression model, we identified miR-146a as a key double-acting player in melanoma malignancy. In fact, miR-146a is able to enhance tumor growth while it suppresses dissemination. We evidenced that melanoma cell growth is coordinated by its direct target lunatic fringe (LFNG) which operates on the NOTCH/PTEN/Akt pathway. Instead, metastasis formation inhibition is linked to decreased expression of ITGAV and ROCK1. Relevantly, miR-146a expression correlates with melanoma recurrence and it is enriched both in patients-derived melanoma and cutaneous metastasis samples, while its direct targets are depleted. However, miR-146a levels drop in Circulating Tumor Cells, suggesting the necessity for miR-146a expression to fluctuate during tumor progression in order to favor tumor growth and allow dissemination. This study reconciles the contradictory biological functions of miR-146a in melanoma progression and unravels distinct molecular mechanisms that need to be considered for therapeutic interventions.
Transcriptome analysis of phosphonate-pretreated tomato in response to inoculation with Phytophthora parasitica
Phosphonate related fungicides such as neutralized phosphorous acid (NPA) are effective for the control of plant diseases caused by Oomycetes including Phytophthora parasitica. It has been proposed that phosphonate may induce plant resistance. However, the mechanism underlying phosphonate-induced resistance remains unclear. The purpose of this study is to identify genes that are differentially expressed in phosphonate-pretreated tomato plants in response to inoculation with Phytophthora parasitica.
Immune correlates of early prednisolone therapy in children and adolescents with dengue
Dengue is the most important arboviral infection of humans. A host pro-inflammatory immune response is widely believed to contribute to the clinical complications that occur in some patients with dengue. Here, immune correlates of early prednisolone therapy were defined in Vietnamese dengue patients enrolled in a randomized controlled trial, comparing a three day regimen of high (2mg/kg) or low (0.5mg/kg) dose prednisolone with placebo. Prednisolone conferred a small change in the whole blood gene expression profile, with 81 transcripts from 64 genes differentially abundant between high-dose prednisolone and placebo treated patients. A prominent theme in the prednisolone gene expression signature was the under-abundance of transcripts from genes associated with T and NK cell cytolytic effector functions. Surprisingly, prednisolone therapy was not associated with attenuation of early-convalescent T cell responses or plasma cytokine levels. Collectively, these findings are consistent with a remarkably benign influence of prednisolone on immune response parameters in dengue patients, and are in line with the trial evidence showing lack of impact on clinical laboratory endpoints and clinical phenotype.
shRNA-mediated knock down of Bmi-1 and Mel-18 in medulloblastoma cells
Bmi-1 and Mel-18 are close structural homologues that belong to the polycomb group (PcG) of transcriptional regulators of homeotic gene expression in development. They are believed to stably maintain repression of gene expression by altering the state of chromatin at specific promoters. A number of clinical and experimental observations have also implicated Bmi-1 in tumorigenesis and stem cell maintenance. Bmi-1 overexpression or amplification has been observed in a number of human malignancies, particularly in B-cell lymphomas, medulloblastomas and breast cancer. We report here that shRNA-mediated knock-down of either Bmi-1 or Mel-18 in human medulloblastoma DAOY cells results in the inhibition of proliferation, loss of clonogenic survival and anchorage-independent growth, and suppression of xenograft tumor formation in nude mice. Furthermore, overexpression of both Bmi-1 and Mel-18 significantly increased clonogenic survival of Rat1 fibroblasts. In contrast, stable downregulation of Bmi-1 or Mel-18 alone did not affect the growth of SK-OV-3 or U2OS cancer cell lines or normal human WI38 fibroblasts. Gene expression analysis of shRNA-expressing DAOY cells has demonstrated a significant overlap in the Bmi-1- and Mel-18-regulated genes and revealed novel gene targets under their control. Taken together, these results suggest that Bmi-1 and Mel-18 might have overlapping functions in human tumorigenesis. Keywords: shRNA knock-down
GAR22: A novel target gene of thyroid hormone receptor causes growth inhibition in human erythroid cells
Objective: Thyroid hormone receptors (TRs) are ligand-dependent transcription factors with a major impact on erythroid cell development. Here we investigated TR activity on red cell gene expression and identified TR target genes. The impact of the TR target gene GAR22 (growth arrest specific 2 [GAS2]-related gene on chromosome 22) on red cell differentiation was determined. Methods: SCF/Epo dependent red cell progenitors were differentiated in vitro in the presence or absence of thyroid hormone. Hormone-induced changes in gene expression were measured by a genome-wide approach with DNA microarrays. Ectopic expression of the TR target gene GAR22 was used to determine its impact on red cell differentiation. Results: Ligand-activated TR effectively accelerated red cell progenitor differentiation in-vitro concomitantly with inducing growth arrest. We demonstrate that activated TR induced specific gene expression patterns of up- or down-regulated genes, including distinct clusters associated with accelerated differentiation in response to treatment. Mining for T3 induced genes identified BTEB1 (basic transcription element binding protein 1/Krüppel-like factor 9) and GAR22 as TR target genes. BTEB1/KLF9 is a known TR target gene while GAR22, initially identified as a putative tumor suppressor, represents a novel TR target gene. We demonstrate that ectopic GAR22 expression in red cell progenitors lengthens the cell cycle and causes growth inhibition, but leaves red cell gene expression unaffected. Conclusion: This study identifies GAR22 as a novel and direct TR target gene. Our results suggest that hormone-induced GAR22 might represent an important trigger of growth inhibition induced by thyroid hormone in red cell progenitors.
PIE cell line: Control vs. ETEC treated or Immunobiotic treated
We investigate the transcriptome response of porcine intestinal epitheliocyte cell line (PIE cells) to the challenge with heat-stable Enterotoxigenic Escherichia coli (ETEC) pathogen-associated molecular patterns (PAMPs) and, the changes induced by Lactobacillus jensenii TL2937 in that response. The transcriptome approach allowed us to obtain a global overview of the immune and immune related genes involved in response of PIE cells to heat-stable ETEC PAMPs. The most remarkable changes in PIE cells after heat-stable ETEC PAMPs challenge were observed in chemokines expressions, followed by cell adhesion molecules and, complement and coagulation cascades factors. We also confirmed that L. jensenii TL2937 differently modulates gene expression in ETEC PAMPs-challenged PIE cells. The microarray gene expression profiles clearly demonstrated that an anti-inflammatory effect was triggered by the immunobiotic strain in PIE cells. The main outcome from the study was the differential regulation of chemokines (CCL8, CXCL5, CXCL9, CXCL10 and CXCL11), complement factors (C1R, C1S, C3 and CFB) and, coagulation system proteins (Tissue factor) expression by L. jensenii TL2937. PIE cells treated with the negative control Lactobacillus plantarum TL2766 showed a transcriptomic response similar to ETEC PAMPs-challenged PIE cells.
Human leukocytes from 6 volunteers before and 2h after pectin capsules consumption (IV)
Methanol (MeOH) is considered to be a poison in humans because of the alcohol dehydrogenase (ADH)-mediated conversion of MeOH into toxic formaldehyde (FA). Our recent genome-wide analysis of the mouse brain demonstrated that an increase in endogenous MeOH after ADH inhibition led to a significant increase in the plasma MeOH concentration and the modification of mRNA synthesis. These findings suggest endogenous MeOH involvement in homeostasis regulation by controlling mRNA levels. Here, we demonstrate directly that study volunteers displayed increasing concentrations of MeOH and FA in their blood plasma when consuming citrus pectin, ethanol and red wine. A microarray analysis of white blood cells (WBC) in volunteers after pectin intake showed various responses for 30 differentially regulated mRNAs. Most of the mRNAs were somehow involved in the pathogenesis of Alzheimer's disease (AD). There was also a decreased synthesis of hemoglobin mRNA, HBA and HBB, the presence of which in WBC RNA was not a result of red blood cells contamination because erythrocyte-specific marker genes did not show significant change. A qRT-PCR analysis of volunteer WBC after pectin and red wine intake confirmed the complicated dependence between plasma MeOH content and the mRNA accumulation of previously identified genes, namely GAPDH and SNX27, and MME, SORL1, DDIT4, HBA and HBB genes revealed in this study. We hypothesized that human plasma MeOH, which is replenished from endogenous and exogenous sources (diet), has an impact on the WBC mRNA levels of genes involved in AD pathogenesis and signaling.
ASFV array analysis
African swine fever virus (ASFV) produces a fatal acute hemorrhagic fever in domesticated pigs that potentially is a worldwide economic threat. Using an expressed sequence tag (EST) library-based antisense method of random gene inactivation and a phenotypic screen for limitation of ASFV replication in cultured human cells, we identified six host genes whose cellular functions are required by ASFV. These included three loci, BAT3 (HLA-B-associated transcript 3), C1qTNF (C1q and tumor necrosis factor-related protein 6), and TOM40 (translocase of outer mitochondrial membrane 40), for which antisense expression from a tetracycline-regulated promoter resulted in reversible inhibition of ASFV production by >99%. The effects of antisense transcription of the BAT3 EST and also of expression in the sense orientation of this EST, which encodes amino acid residues 450 to 518 of the mature BAT3 protein, were investigated more extensively. Sense expression of the BAT3 peptide, which appears to reversibly interfere with BAT3 function by a dominant negative mechanism, resulted in decreased synthesis of viral DNA and proteins early after ASFV infection, altered transcription of apoptosis-related genes as determined by cDNA microarray analysis, and increased cellular sensitivity to staurosporine-induced apoptosis. Antisense transcription of BAT3 reduced ASFV production without affecting abundance of the virus macromolecules we assayed. Our results, which demonstrate the utility of EST-based functional screens for the detection of host genes exploited by pathogenic viruses, reveal a novel collection of cellular genes previously not known to be required for ASFV infection. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Aluminum-inducible genes
Aluminum (Al) toxicity, which is caused by the solubilization of Al3 in acid soils resulting in inhibition of root growth and nutrient/water acquisition, is a serious limitation to crop production, because up to one-half of the world?s potentially arable land is acidic. To date, however, no Al tolerance genes have yet been cloned. The physiological mechanisms of tolerance are somewhat better understood; the major documented mechanism involves the Al-activated release of Al-binding organic acids from the root tip, preventing uptake into the primary site of toxicity. In this study, a quantitative trait loci analysis of Al tolerance in Arabidopsis was conducted, which also correlated Al tolerance quantitative trait locus (QTL) with physiological mechanisms of tolerance. The analysis identified two major loci, which explain approximately 40% of the variance in Al tolerance observed among recombinant inbred lines derived from Landsberg erecta (sensitive) and Columbia (tolerant). We characterized the mechanism by which tolerance is achieved, and we found that the two QTL cosegregate with an Al-activated release of malate from Arabidopsis roots. Although only two of the QTL have been identified, malate release explains nearly all (95%) of the variation in Al tolerance in this population. Al tolerance in Landsberg erecta Columbia is more complex genetically than physiologically, in that a number of genes underlie a single physiological mechanism involving root malate release. These findings have set the stage for the subsequent cloning of the genes responsible for the Al tolerance QTL, and a genomics-based cloning strategy and initial progress on this are also discussed. A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments. Keywords: replicate_design
Profiling microRNAs in Eucalyptus grandis reveals no mutual relationship between alterations in miR156 and miR172 expression and adventitious root induction during development
Background: The change from juvenile to mature phase in woody plants is often accompanied by a gradual loss of rooting ability, as well as by reduced microRNA (miR) 156 and increased miR172 expression. Results: We characterized the population of miRNAs of Eucalyptus grandis and compared by Northern blot the gradual reduction in miR156 and increase in miR172 expression during development to the loss of rooting ability. Forty known and eight novel miRNAs were discovered and their predicted targets are listed. The expression pattern of nine miRNAs was determined during adventitious root formation in juvenile and mature cuttings. While the expression levels of miR156 and miR172 were inverse in juvenile and mature tissues, no mutual relationship was found between high miR156 expression and rooting ability, or high miR172 expression and loss of rooting ability. This is shown both in E. grandis and also in E. brachyphylla, in which explants that underwent rejuvenation in tissue culture conditions were also examined. Conclusions: It is suggested that in these Eucalyptus species, there is no correlation between the switch of miR156 with miR172 expression in the stems and the loss of rooting ability.
Haemopedia: An Expression Atlas of Murine Haematopoietic Cells
Haematopoiesis is a multi-stage process that involves the differentiation of multipotent stem cells and progenitor cells into distinct mature cell lineages. Here we present Haemopedia, a comprehensive atlas of murine gene expression data that covers all the mature lineages in haematopoiesis, including rare cell populations such as eosinophils, mast cells, basophils and megakaryocytes and a large collection of progenitor and stem cells. We have used this dataset to identify gene sets with specifically enriched expression in each of the mature blood cell lineages. Many of the genes in these sets show conserved lineage-enriched expression patterns in human haematopoiesis. We also identify some genes with divergent expression patterns between mouse and human, highlighting species specific differences in blood cell production. To make analyses of Haemopedia and other blood cell transcriptional datasets easier, we have created an online web portal, Haemosphere, which provides simple tools to interrogate gene expression-based relationships between haematopoietic cell types and genes of interest.
Gene expression studies in IEC-6 cells induced by non-steroidal anti-inflammatory agents
Non-steroidal anti-inflammatory drugs (NSAIDs) are used extensively as therapeutic agents, despite their well-documented gastrointestinal (GI) toxicity. Presently, the mechanisms responsible for NSAID-associated GI damage are incompletely understood. In this study, we used Microarray analysis to generate a novel hypothesis about cellular mechanisms that underlie the GI toxicity of NSAIDs. Monolayers of intestinal epithelial cells (IEC-6) were treated with NSAIDs that either exhibit indomethacin, NS-398) or lack (SC-560) inhibitory effects on intestinal epithelial cell migration. Bioinformatic analysis of array data suggested that NSAIDs with adverse GI effects either decrease the gene expression of the calpains or increase the gene expression of the calpain engodenous inhibitor, calpastatin. Calpains have been shown previously to modulate the migration of a variety of cells in different physiological contexts. Our experimental results suggest that the altered expression of calpain genes may contribute to the adverse effects of NSAIDs on intestinal epithelial restitution. Microarray analysis has generated the novel hypothesis that the GI toxicity of NSAIDs may be attributed in part to drug-induced changes in the expression and activity of calpains. Keywords: dose response
5-hmC in the brain: abundance in synaptic genes and differences at the exon-intron boundary (tiling array)
5-hydroxymethylcytosine (5-hmC), a derivative of 5-methylcytosine (5-mC), is abundant in the brain for unknown reasons. We mapped the genomic distribution of 5-hmC and 5-mC in human and mouse tissues using glucosylation of 5-hmC coupled with restriction enzyme digestion, and interrogation on microarrays. We detected 5-hmC enrichment in genes with synapse-related functions in the brain. We also identified significant, tissue-specific differential distributions of these DNA modifications at the exon-intron boundary, in both human and mouse. This boundary change was mainly due to 5-hmC in the brain, but due to 5-mC in non-neural contexts. This pattern was replicated in multiple independent datasets, and the brain-specific change in 5-hmC was validated using single-molecule sequencing. Moreover, in the brain, constitutive exons contained higher levels of 5-hmC, relative to alternatively-spliced exons. Our study suggests a novel role for 5-hmC in RNA splicing and synaptic function in the brain
Transcriptional profiles induced by either androgen depletion or androgen receptor knockdown
Although the vital role of the androgen receptor (AR) has been well demonstrated in primary prostate cancers, its role in the androgen-insensitive prostate cancers still remains unclear. Here, we used a small hairpin RNA approach to directly assess AR activity in prostate cancer cells. Reduction of AR expression in the two androgen-sensitive prostate cancer cell lines, LNCaP and LAPC4, significantly decreased AR-mediated transcription and cell growth. Intriguingly, in two androgen-insensitive prostate cell lines, LNCaP-C42B4 and CWR22Rv1, knockdown of AR expression showed a more pronounced effect on AR-induced transcription and cell growth than androgen depletion. Using cDNA microarrays, we also compared the transcriptional profiles induced by either androgen depletion or AR knockdown. Although a significant number of transcripts appear to be regulated by both androgen depletion and AR knockdown, we observed a subset of transcripts affected only by androgen depletion but not by AR knockdown, and vice versa. Finally, we demonstrated a direct role for AR in promoting tumor formation and growth in a xenograft model. Taken together, our results elucidate an important role for the AR in androgen-insensitive prostate cancer cells, and suggest that AR can be used as a therapeutic target for androgen-insensitive prostate cancers. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
Leishmania major infection-induced changes in the small RNA transcriptome of host macrophages.
Protozoan parasites of the genus Leishmania are the causative agent of leishmaniasis, one of the 13 most important tropical diseases. Leishmania persists as endo-parasite in host macrophages, where it uses multiple strategies to manipulate the microbicidal host cell functions and to escape from the host immune system. Understanding how Leishmania interacts with host macrophages during uptake, differentiation, intracellular replication, and release might be the key to develop new drugs in target-directed approaches to treat patient with leishmaniasis. Short non-coding RNAs are known to regulate the expression of protein-coding genes at post-transcriptional level. Characterization of these processes during Leishmania infection provides deeper insight in the interaction between host and parasites.
The Enzyme-Like Domain of Arabidopsis Nuclear Beta-Amylases is Critical During DNA Sequence Recognition and Transcriptional Activation
Plant BZR1-BAM transcription factors contain a β-amylase (BAM)-like domain, characteristic of proteins involved in starch breakdown. The enzyme-derived domains appear to be non-catalytic, but determine the function of the Arabidopsis thaliana BZR1-BAMs (BAM7 and BAM8) during transcriptional initiation. Microarray experiments with plants overexpressing different mutant versions of the proteins show that only functional BZR1-BAM variants deregulate gene expression and cause leaf developmental abnormalities. Transcriptional changes caused by overexpression of the BZR1 domain alone indicate that the BAM domain increases selectivity for the preferred cis-regulatory element BBRE (BZR1-BAM Responsive Element). In this study, we used the ATH1 GeneChip microarray to investigate transcript abundance in different Arabidopsis thaliana genotypes.
mutant axel-4 seedlings
A mutant screen was conducted in Arabidopsis that was based on deregulated expression of auxin-responsive transgenes. Two different tightly regulated (i.e., very low expression in the absence of auxin treatment and very high expression after exogenous auxin treatment) auxin-responsive promoters were used to drive the expression of both a ?-glucuronidase (GUS) reporter gene and a hygromycin phosphotransferase (HPH)?selectable marker gene. This screen yielded several mutants, and five of the mutations (axe1-1 to axe1-5) mapped to the same locus on chromosome 5. A map-based cloning approach was used to locate the axe1 mutations in an Arabidopsis RPD3-like histone deacetylase gene, referred to as HDA6. The axe1 mutant plants displayed increased expression of the GUS and HPH transgenes in the absence of auxin treatment and increased auxin-inducible expression of the transgenes compared with nonmutant control plants. None of a variety of endogenous, natural auxin-inducible genes in the mutant plants were upregulated like the transgenes, however. Results of treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine suggest that the axe1 mutations affect transgene silencing; however, histone deacetylase inhibitors had no affect on transgene silencing in mutant or control plants. The specific effect of AtHDA6 mutations on the auxin-responsive transgenes implicates this RPD3-like histone deacetylase as playing a role in transgene silencing. Furthermore, the effect of AtHDA6 on transgene silencing may be independent of its histone deacetylase activity. A replicate experimental design type is where a series of replicates are performed to evaluate reproducibility or as a pilot study to determine the appropriate number of replicates for a subsequent experiments. Keywords: replicate_design
Exploration of the Drug Action of Capreomycin on Mycobacterium tuberculosis
Multi-drug resistance and latent infection are two major issues in current tuberculosis (TB) control and management. Capreomycin is an important drug used for TB with multi-drug resistance. A recent study also indicates that this drug possesses unique bactericidal activity against non-replicating TB bacilli among known anti-TB drugs. Thus, there is an urgent need for investigating the full-spectrum action of capreomycin. Here we conduct the first microarray-based study on capreomycin using the high-resolution Affymetrix oligonucleotide GeneChip system. The results indicate that capreomycin primarily acts on the information pathways but it also significantly affects cell wall, cell processes, intermediate metabolism and respiration in Mycobacterium tuberculosis. This study not only transcriptionally validates the specific molecular target, 16S rRNA, but also discovers potential new targets of capreomycin, including genes operating at the DNA level, such as Rv0054 (ssb) and Rv3715c (recR), as well as genes involved in cell division like Rv3260c (whiB2). In addition, the nuo gene cluster and the ATP synthase gene cluster are repressed. Keywords: Drug-induced Differential gene expression analysis
UVB-induced persistent activation of cellular pathways revealed by a loop-designed microarray approach
Ultraviolet B (UVB) irradiation has strong biological effects and modulates the expression of many genes. However, the major biological themes affected by UVB remain poorly understood. This work employs a loop-designed microarray approach and applies a log linear model along with multiple hypotheses testing to identify differentially regulated genes at 4, 8, 16, or 24 hours following UVB irradiation. The most prominent biological themes in lists of differentially regulated gene sets were extracted by functional enrichment analysis using DAVID bioinformatics resources 2007. By this approach, we identify that genes that participate in two prime cellular processes – the ribosome pathway and the oxidative phosphorylation pathway - are persistently activated over a period of 24 hours following UVB irradiation. Microarray results were further verified by both mitochondrial activity assay and real-time PCR analysis. These data suggest that the persistent activation of ribosome and oxidative phosphorylation pathways may have a key role in UVB-induced cellular responses. For the first time, the specific cellular pathways that respond to UVB irradiation consistently and persistently can be delineated confidently using a loop-designed microarray approach and functional bioinformatics analysis. The results of this study offer further insight into UVB-induced stress responses. Keywords: UVB, cDNA microarray, loop design, KEGG pathway
Rice bHLH transcription factor RERJ1 dependent wound inducible genes in rice leaves
The plant hormone jasmonic acid (JA) has been known as a signal molecule that is induced by various stresses and mediates plant defense responses. Rice O. sativa inductively produces variety of defensive compounds upon abiotic and biotic stress conditions, such as wounding and insect attack. The bHLH transcription factor RERJ1 has previously been identified as JA-inducible factor whose expression is also rapidly induced by wounding. We identified RERJ1-dependent and wound-inducible genes by comparison with transcriptomes of wound treated wild-type and a Tos17-rerj1 defective mutant rice.
New molecular phenotypes in the dst mutants of Arabidopsis revealed by DNA microarray analysis
In this study, DNA microarray analysis was used to expand our understanding of the dst1 mutant of Arabidopsis. The dst (downstream) mutants were isolated originally as specifically increasing the steady state level and the half-life of DST-containing transcripts. As such, they offer a unique opportunity to study rapid sequence-specific mRNA decay pathways in eukaryotes. These mutants show a threefold to fourfold increase in mRNA abundance for two transgenes and an endogenous gene, all containing DST elements, when examined by RNA gel blot analysis; however, they show no visible aberrant phenotype. Here, we use DNA microarrays to identify genes with altered expression levels in dst1 compared with the parental plants. In addition to verifying the increase in the transgene mRNA levels, which were used to isolate these mutants, we were able to identify new genes with altered mRNA abundance in dst1. RNA gel blot analysis confirmed the microarray data for all genes tested and also was used to catalog the first molecular differences in gene expression between the dst1 and dst2 mutants. These differences revealed previously unknown molecular phenotypes for the dst mutants that will be helpful in future analyses. Cluster analysis of genes altered in dst1 revealed new coexpression patterns that prompt new hypotheses regarding the nature of the dst1 mutation and a possible role of the DST-mediated mRNA decay pathway in plants. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
hnRNP R and its main interactor, the noncoding RNA 7SK, coregulate the axonal transcriptome of motoneurons
Disturbed RNA processing and subcellular transport contribute to the pathomechanisms of motoneuron diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. RNA-binding proteins are involved in these processes, but the mechanisms how they regulate the subcellular diversity of transcriptomes, in particular in axons, are not understood. hnRNP R interacts with several proteins involved in motoneuron diseases. It is located in axons of developing motoneurons and its depletion causes defects in axon growth. Here, we used iCLIP to determine the RNA interactome of hnRNP R in motoneurons. We identified ~3,500 RNA targets, predominantly with functions in synaptic transmission and axon guidance. Among the RNA targets identified by iCLIP, the non-coding RNA 7SK was the top interactor of hnRNP R. We detected 7SK in the nucleus but also in the cytosol of motoneurons. In axons, 7SK localized in close proximity to hnRNP R and depletion of hnRNP R reduced axonal 7SK. Furthermore, suppression of 7SK led to defective axon growth that was accompanied by axonal transcriptome alterations similar to those caused by hnRNP R depletion. Using a series of 7SK deletion mutants we show that the function of 7SK in axon elongation depends on its interaction with hnRNP R but not with the pTEF-B complex involved in transcriptional regulation. These results propose a role of 7SK as essential interactor of hnRNP R to regulate its function in axon maintenance.
SMO variants explain the majority of drug resistance in basal cell carcinoma [exome-seq]
Advanced basal cell carcinomas (BCCs) frequently acquire resistance to Smoothened (SMO) inhibitors through unknown mechanisms, providing a unique opportunity to study human tumor evolution. Here, we identify SMO mutations in 50% (22/44) of resistant BCCs compared with 5.6% (2/36) of untreated BCCs (p<0.0001), and show that these mutations maintain Hedgehog signaling in the presence of SMO inhibitors. Alterations include four ligand binding pocket (LBP) mutations that define sites of inhibitor binding and four variants that confer constitutive activity and inhibitor resistance, thus defining pivotal residues of SMO that ensure receptor autoinhibition. Finally, we show that both classes of SMO variants respond to the aPKC-ι/λ inhibitor PSI and GLI2 antagonist ATO that operate downstream of SMO.
Analysis of transcriptional signatures in response to Listeria monocytogenes infection reveals temporal and strain dependent changes in interferon signalling
Listeriosis is an infectious disease caused by the intracellular bacterium Listeria monocytogenes. To control the infection effectively, the host immune response is directed by intercellular signalling molecules called cytokines that are produced by immune cells following sensing of the bacteria. In this study we used gene expression analysis to examine complex immune signalling networks in the blood and tissues of mice infected with L. monocytogenes. We show that a large set of genes are perturbed in both blood and tissue upon infection and that the transcriptional responses in both are enriched for pathways of the immune response. From these data we also observe an important signalling network emerge from a group of cytokines called interferons (IFNs). Previous findings suggest that different IFN family members can determine the balance between successful and impaired immune responses to L. monocytogenes and several other bacterial infections. Using mice deficient for the detrimental ‘type I’ IFN signalling pathway we show that IFN-inducible genes are differentially regulated at different times upon infection but also present at much lower levels in uninfected mice highlighting how dysregulation of this network in the steady state may determine the outcome of this bacterial infection.
SMO variants explain the majority of drug resistance in basal cell carcinoma [RNA-Seq]
Advanced basal cell carcinomas (BCCs) frequently acquire resistance to Smoothened (SMO) inhibitors through unknown mechanisms, providing a unique opportunity to study human tumor evolution. Here, we identify SMO mutations in 50% (22/44) of resistant BCCs compared with 5.6% (2/36) of untreated BCCs (p<0.0001), and show that these mutations maintain Hedgehog signaling in the presence of SMO inhibitors. Alterations include four ligand binding pocket (LBP) mutations that define sites of inhibitor binding and four variants that confer constitutive activity and inhibitor resistance, thus defining pivotal residues of SMO that ensure receptor autoinhibition. Finally, we show that both classes of SMO variants respond to the aPKC-ι/λ inhibitor PSI and GLI2 antagonist ATO that operate downstream of SMO
Distinct ErbB-2-coupled signalling pathways promote mammary tumors with unique pathological and transcriptional profiles
ErbB-2 overexpression and amplification occurs in 15 - 30% of human invasive breast carcinomas associated with poor clinical prognosis. Previously, we have demonstrated that four ErbB-2/Neu tyrosine-autophosphorylation sites within the cytoplasmic tail of the receptor recruit distinct adaptor proteins and are sufficient to mediate transforming signals in vitro. Two of these sites representing the Grb2 (Neu-YB) and Shc (Neu-YD) binding sites can induce mammary tumourigenesis and metastasis. Here we show that Neu-YC and Neu-YE transgenic mice develop metastatic mammary tumours. A detailed comparison of pathological and transcriptional profiles among all Neu mutant mouse models revealed that Neu-YC, -YD and -YE mammary tumours shared similar pathological and transcriptional features correlating with their capacity to signal through a common adaptor like Shc. In contrast, the Neu-YB mouse model displayed a unique pathology with a high metastatic potential that correlates with a distinct transcriptional profile. We identified genes specifically expressed in YB-induced mammary tumours, including CXCL12/SDF-1α that promotes malignant tumour progression. Furthermore, Neu-YB tumour epithelial cells showed abundant intracellular CXCL12/SDF-1α protein, which may reflect the more aggressive phenotype among all Neu mutant mouse models. These findings indicate that activation of distinct Neu-coupled signalling pathways has a deep impact on the biological behaviour of Neu-induced tumours. Keywords: genetic modification, Neu mutant mouse models, mammary tumor
SMO variants explain the majority of drug resistance in basal cell carcinoma [Target Sequencing]
Advanced basal cell carcinomas (BCCs) frequently acquire resistance to Smoothened (SMO) inhibitors through unknown mechanisms, providing a unique opportunity to study human tumor evolution. Here, we identify SMO mutations in 50% (22/44) of resistant BCCs compared with 5.6% (2/36) of untreated BCCs (p<0.0001), and show that these mutations maintain Hedgehog signaling in the presence of SMO inhibitors. Alterations include four ligand binding pocket (LBP) mutations that define sites of inhibitor binding and four variants that confer constitutive activity and inhibitor resistance, thus defining pivotal residues of SMO that ensure receptor autoinhibition. Finally, we show that both classes of SMO variants respond to the aPKC-ι/λ inhibitor PSI and GLI2 antagonist ATO that operate downstream of SMO
AKT regulates de novo induction of Foxp3
The CD4+Foxp3+ regulatory T cells play an essential role in maintaining tolerance via their suppressive function on conventional T cells. The intracellular signaling pathways that regulate Foxp3 expression are largely unknown. In this study we describe a novel inhibitory role for AKT in regulating de novo induction of Foxp3 both in vivo and in vitro. A constitutively active allele of AKT significantly diminished TGF-â induced Foxp3 induction via a rapamycin-sensitive pathway, establishing a role for the AKT-mTOR axis in Treg cells. Moreover, the observed impairment in Foxp3 induction was paralleled by a selective downmodulation of the imparted Treg transcriptional signature highlighting the importance of the balance of intracellular signals in Treg differentiation . Our results provide a basis for further elucidation of molecular mechanisms that regulate Foxp3 induction and identify AKT as an important negative regulator of this process. Keywords: Cell population comparison
Atm-/-,mTerc-/-,p53-/- triple knock-out lymphoma vs normal mouse DNA (GPL4092)
Highly rearranged and mutated cancer genomes present major challenges in the identification of pathogenetic events driving the cancer process. Here, we engineered lymphoma-prone mice with chromosomal instability to assess the utility of mouse models in cancer gene discovery and the extent of cross-species overlap in cancer-associated copy number aberrations. Integrating with targeted re-sequencing, our comparative oncogenomic studies efficiently identified FBXW7 and PTEN as commonly deleted or mutated tumor suppressors in human T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). More generally, the murine cancers acquire widespread recurrent clonal amplifications and deletions targeting loci syntenic to alterations present in not only human T-ALL but also diverse tumors of hematopoietic, mesenchymal and epithelial types. These results thus support the view that murine and human tumors experience common biological processes driven by orthologous genetic events as they evolve towards a malignant phenotype. The highly concordant nature of genomic events encourages the use of genome unstable murine cancer models in the discovery of biologically relevant driver events in human cancer. Keywords: comparative genomic hybridization, genetic modification
Human Pancreas tumor vs Normal Human DNA
Highly rearranged and mutated cancer genomes present major challenges in the identification of pathogenetic events driving the cancer process. Here, we engineered lymphoma-prone mice with chromosomal instability to assess the utility of mouse models in cancer gene discovery and the extent of cross-species overlap in cancer-associated copy number aberrations. Integrating with targeted re-sequencing, our comparative oncogenomic studies efficiently identified FBXW7 and PTEN as commonly deleted or mutated tumor suppressors in human T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). More generally, the murine cancers acquire widespread recurrent clonal amplifications and deletions targeting loci syntenic to alterations present in not only human T-ALL but also diverse tumors of hematopoietic, mesenchymal and epithelial types. These results thus support the view that murine and human tumors experience common biological processes driven by orthologous genetic events as they evolve towards a malignant phenotype. The highly concordant nature of genomic events encourages the use of genome unstable murine cancer models in the discovery of biologically relevant driver events in human cancer. Keywords: comparative genomic hybridization
Identification of alternatively spliced transcripts in brain metastatic derivatives of MDA-MB-231 breast cancer cells in response to RBM47 expression
Changes in alternative splicing in breast cancer cells expressing control, empty vector or Flag-tagged wild type RBM47 were analyzed using paired-end, 100bp RNAseq. Related data published together with these data are found in GSE53779
Atm-/-,mTerc-/-,p53-/- triple knock-out lymphoma vs normal mouse DNA (GPL2884)
Highly rearranged and mutated cancer genomes present major challenges in the identification of pathogenetic events driving the cancer process. Here, we engineered lymphoma-prone mice with chromosomal instability to assess the utility of mouse models in cancer gene discovery and the extent of cross-species overlap in cancer-associated copy number aberrations. Integrating with targeted re-sequencing, our comparative oncogenomic studies efficiently identified FBXW7 and PTEN as commonly deleted or mutated tumor suppressors in human T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). More generally, the murine cancers acquire widespread recurrent clonal amplifications and deletions targeting loci syntenic to alterations present in not only human T-ALL but also diverse tumors of hematopoietic, mesenchymal and epithelial types. These results thus support the view that murine and human tumors experience common biological processes driven by orthologous genetic events as they evolve towards a malignant phenotype. The highly concordant nature of genomic events encourages the use of genome unstable murine cancer models in the discovery of biologically relevant driver events in human cancer. Keywords: comparative genomic hybridization, genetic modification
Flag-RBM47 HITS-CLIP in brain metastatic derivatives of MDA-MB-231
Brain metastatic breast cancer cells were subjected to HITS-CLIP to identify the targets of the RNA binding protein RBM47 MDA231-BrM2a is characterized in PMID: 19421193; Related data published together with these data are found in GSE53779
MicroRNAs 24 and 27 suppress allergic inflammation and target a network of regulators of T helper-2 cell-associated cytokine production
MicroRNAs (miRNAs) are important regulators of cell fate decisions in immune responses. They act by coordinate repression of multiple target genes, a property that we exploited to uncover regulatory networks that govern T helper-2 (Th2) cells. A functional screen of individual miRNAs in primary T cells uncovered multiple miRNAs that inhibited Th2 cell differentiation. Among these were miR-24 and miR-27, miRNAs coexpressed from two genomic clusters, which each functioned independently to limit interleukin-4 (IL-4) production. Mice lacking both clusters in T cells displayed increased Th2 cell responses and tissue pathology in a mouse model of asthma. Gene expression and pathway analyses placed miR-27 upstream of genes known to regulate Th2 cells. They also identified targets not previously associated with Th2 cell biology which regulated IL-4 production in unbiased functional testing. Thus, elucidating the biological function and target repertoire of miR-24 and miR-27 reveals regulators of Th2 cell biology.
Expression of inflammatory host genes in Chlamydia trachomatis infected human monocytes
Messenger RNA of C trachomatis infected monocytes of the three healthy donors was compared with the corresponding mock-infected samples. For mock infection, SPG buffer was used instead of the C trachomatis suspension, all other procedures were performed identically. Cells were resuspended in solution D and total RNA was extracted by application of phenol:chloroform 5:1 (pH 4.5, Ambion, Austin, TX) followed by precipitation in isopropanol at -80°C for 1 hr and incubation with RQ1 DNase (Promega, Madison, WI) at 37 °C for 1 hr. The signal intensity of the G3PDH housekeeping gene on the microarray membrane was used as indirect quality marker for the RNA utilized as only experiments were included in the analysis that revealed a G3PDH signal intensity within 1.5 times the standard deviation of all membranes evaluated in our study. The entire microarray procedure and its analysis has recently been validated and reported in detail. Total RNA of all donors was pooled and for each microarray experiment 150 µg were reverse transcribed and amplified by SMART™-PCR (BD Biosciences Clontech, Palo Alto, CA), a technology that allows reverse transcription of small amounts of total RNA and subsequent amplification of the entire cDNA. Probes were labeled with 32P and subsequently over night hybridized to a filter-based nylon membrane containing immobilized cDNA-specific sequences from a total of 1,184 genes (Human Atlas Array 1.2, BD Biosciences Clontech, Palo Alto, CA). For analysis, we focused solely on the 159 cytokines, chemokines and their receptors as given by the manufacturer. Signal intensities were retrieved by a STORM 860 scanner (Molecular Dynamics, Sunnyvale, CA) in combination with the AtlasImage 2.0 software (BD Biosciences Clontech). Data from all signal intensities were then subtracted by the local background intensity measured around each gene. The local background intensities of all individual genes were subsequently averaged, resulting in the mean background intensity of a particular membrane. Gene expression in our experiments was determined by a spot intensity of a single transcript that exceeded twice the mean background. Normalisation to background and to the G3PDH housekeeping gene was achieved by the global (sum) normalization method. Signal intensity data are given as the ratio of C trachomatis infected vs mock infected probes. Keywords: expression analysis
The identification of RBM47 binding sites and RBM47-dependent alternative splicing events in brain metastatic breast cancer cells
This SuperSeries is composed of the SubSeries listed below.
Human GBM tumor vs Normal Human DNA
Highly rearranged and mutated cancer genomes present major challenges in the identification of pathogenetic events driving the cancer process. Here, we engineered lymphoma-prone mice with chromosomal instability to assess the utility of mouse models in cancer gene discovery and the extent of cross-species overlap in cancer-associated copy number aberrations. Integrating with targeted re-sequencing, our comparative oncogenomic studies efficiently identified FBXW7 and PTEN as commonly deleted or mutated tumor suppressors in human T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). More generally, the murine cancers acquire widespread recurrent clonal amplifications and deletions targeting loci syntenic to alterations present in not only human T-ALL but also diverse tumors of hematopoietic, mesenchymal and epithelial types. These results thus support the view that murine and human tumors experience common biological processes driven by orthologous genetic events as they evolve towards a malignant phenotype. The highly concordant nature of genomic events encourages the use of genome unstable murine cancer models in the discovery of biologically relevant driver events in human cancer. Keywords: comparative genomic hybridization