Gene expression profiling of normal hematopoietic cell subpopulations
Gene expression signatures in childhood acute leukemias are largely unique and distinct from those of normal tissues and other malignancies.
Specimen part
View SamplesHuman brown fat tumors (hibernomas) display concomitant loss of the tumor suppressor genes MEN1 and AIP. In the present study, we hypothesized that the brown fat phenotype is attributed to these mutations. Accordingly, we demonstrate that silencing of AIP in human brown preadipocytic and white fat cell lines results in the induction of the brown fat marker UCP1. In human adipocytic tumors, loss of MEN1 was found both in white (one out of 51 lipomas) and brown fat tumors. In contrast, concurrent loss of AIP was always accompanied by a brown fat morphology. We conclude that this white-to-brown phenotype switch in brown fat tumors is mediated by the loss of AIP.
Loss of the tumour suppressor gene AIP mediates the browning of human brown fat tumours.
Specimen part
View SamplesAcute myeloid leukemia (AML) is associated with poor prognosis, and there is a strong need to develop new therapeutic strategies to improve treatments. We performed a cytokine screen with 114 recombinant proteins to identify selective negative regulators of primitive murine AML cells relative to normal bone marrow cells. The top candidate identified was interleukin 4 (IL4), as it showed the most selective inhibition of leukemia cell growth. Stimulating leukemia cells ex vivo with IL4 and transplanting the cells into mice resulted in reduced leukemia burden and prolonged survival compared with controls. In contrast, IL4 did not inhibit the function of normal hematopoietic stem and progenitor cells in long-term bone marrow repopulation assays. Moreover, we found that IL4 treatment of leukemia cells induced Stat6 phosphorylation, and that leukemia cells with Stat6 knocked out using CRISPR/Cas9-genetic engineering were partially resistant to IL4 stimulation, revealing Stat6 as a critical mediator of the IL4 effect. To evaluate whether IL4 has in vivo therapeutic efficacy, we expressed IL4 ectopically in leukemia cells in vivo and also injected IL4 into leukemic mice; both strategies resulted in the suppression of the leukemia cell burden and increased survival. Further analysis revealed that IL4 treatment induces apoptosis in the leukemia cells. Importantly, IL4 exposure also inhibited the growth and survival of primary AML patient cells. In summary, these findings demonstrate that IL4 selectively inhibits AML cells in a Stat6-dependent manner, thus revealing IL4 as a candidate therapeutic agent in AML. IL4 (ProSpec, East Brunswick NJ, USA) was resuspended following the provider guidelines and stored in aliquotes at -80 °C. Mouse MLL-AF9 leukemia cells were provided by Dr. Benjamin Ebert (Brigham and Women’s Hospital, Boston MA, USA). The murine leukemia cells were cultured in SFEM (StemCell Tech) supplemented with 1% penicillin/streptomycin at 37 °C with 5% CO2. Overall design: Mouse MLL-AF9 leukemia cells were grown in 20 ng/mL IL3 with or without IL4 (100 ng/mL) for 18 hours.
Interleukin 4 induces apoptosis of acute myeloid leukemia cells in a Stat6-dependent manner.
Specimen part, Subject
View SamplesEbf1 is a transcription factor with documented, and dose dependent, functions in both normal and malignant B-lymphocyte development. In order to understand more about the role of Ebf1 in malignant transformation, we have investigated the impact of reduced functional Ebf1 dose on early B-cell progenitors. Gene expression analysis in loss and gain of function analysis suggested that Ebf1 was involved in the regulation of genes of importance for DNA repair as well as cell survival. Investigation of the level of DNA damage in steady state as well as after induction of DNA damage by UV light supported that pro-B cells lacking one functional allele of Ebf1 display a reduced ability to repair DNA damage. This was correlated to a reduction in expression of Rad51 and combined analysis of published 4C and chromatin Immuno precipitation data suggested that this gene is a direct target for Ebf1. Even though the lack of one allele of Ebf1 did not result in any dramatic increase of tumor formation, we noted a dramatic increase in the formation of pro-B cell leukemia in mice carrying a combined heterozygote mutation in the Ebf1 and Pax5 genes. Even though the tumors were phenotypically similar and stable, we noted a large degree of molecular heterogeneity well in line with a mechanism involving impaired DNA repair. Our data support the idea that Ebf1 controls homologous DNA repair in a dose dependent manner and that this may explain the frequent involvement of Ebf1 in human leukemia
Ebf1 heterozygosity results in increased DNA damage in pro-B cells and their synergistic transformation by Pax5 haploinsufficiency.
Specimen part, Cell line, Time
View SamplesThe 8p11 myeloproliferative syndrome (EMS), also referred to as the stem cell leukemia/lymphoma syndrome, is a chronic myeloproliferative disorder that rapidly progresses into an acute leukemia. Molecularly, EMS is characterized by fusion of various partner genes to the FGFR1 gene, resulting in constitutive activation of the tyrosine kinase activity within FGFR1. The two most common fusion genes in human EMS are ZMYM2/FGFR1 (previously known as ZNF198/FGFR1) and BCR/FGFR1. To study the transcriptional programs becoming deregulated by the FGFR1 fusion genes, global gene expression analysis on human CD34+ cord blood cells expressing either of the fusion oncogenes ZMYM2/FGFR1 and BCR/FGFR1 was performed. As a reference gene we also included the more studied BCR/ABL1 fusion oncogene associated with chronic myeloid leukemia. We found that the 3 different fusion oncogenes had in common the upregulation of several genes involved in the JAK/STAT signalling pathway and also other sets of genes. However, the gene expression profiles were not identical, suggesting that both the tyrosine kinase containing gene and the partner gene would affect the transcription of downstream target genes.
Modeling the human 8p11-myeloproliferative syndrome in immunodeficient mice.
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View SamplesATFS-1 has been shown to regulate transcription of mitochondrial chaperone genes such as mtHsp70/hsp-6 and hsp-60 in response to mitocondrial stress. To identify the entire ATFS-1-mediated response, we compared the transcript profiles from wild-type and atfs-1(tm4525) worms raised in the absence and presence of mitochondrial stress.
Mitochondrial import efficiency of ATFS-1 regulates mitochondrial UPR activation.
Specimen part
View SamplesAndrogen receptor (AR) is a ligand-dependent transcription factor that plays a key role in the onset and progression of prostate cancer. We investigated AR-induced gene expression in prostate cancer cells LNCaP and abl by transfecting siAR / siControl or treating cells with androgen (DHT) over a time course.
Androgen receptor regulates a distinct transcription program in androgen-independent prostate cancer.
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View SamplesWe measured gene expression across the whole genome in a panel of lines selected for a wing shape trait (angular offset). The lines were created in separate experiments, originating from two widely separated populations, and including multiple replicates of one population, but all were created using the same selection regime and trait. Here we evaluate the data with two objectives: 1) to identify candidate wing shape genes for future testing and validation, and 2) to assess variation among lines in the outcome of identical selection regimes
Microarray analysis of replicate populations selected against a wing-shape correlation in Drosophila melanogaster.
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View SamplesMethods: CaMKIIa-creERT2 (Erdmann et al., 2007) and Dicer1f/f (Harfe et al., 2005) were crossed to produce inducible forebrain-restricted Dicer1 knockout mice (Dicer-ifKO) mice. Hippocampal mRNA profiles of 3-month-old wild-type (WT) and (Dicer-ifKO) mice were generated by deep sequencing, in triplicate, using Illumina HiSeq 2500. Each sample included total RNA isolated from the hippocampus of 3 mice. In total, 12 mice per genotype were used. The sequence reads that passed quality filters were mapped to reference genome (GRCm38/mm10) using Bowtie 2 (2.0.5) and TopHat (2.0.6). SAM/BAM files were further processed with Samtools (0.1.18). Read count quantitations were obtained using Seqmonk (0.26.0). Normalization of read counts and differential expression analysis between genotypes was carried out using DESeq2 R package from Bioconductor (Release 2.13). qRT–PCR validation was performed using SYBR Green assays. Results: We mapped about 13-14 million sequence reads per sample to the mouse genome (build GRCm38/mm10) and quantified 76,938 annotated transcripts. DESeq2 R package was used to normalize the counts and perform the differential expression. Differential analysis output was filtered by FDR threshold (padj < 0.1). This approach led us to identify 641 gene isoforms, corresponding to 314 genes that were differentially regulated in the mouse hippocampus upon Dicer ablation. Conclusions: We extend here the characterization of inducible forebrain-restricted Dicer1 mutants confirming the initial memory improvement. Moreover, we describe several novel phenotypes associated with early Dicer loss in the mature brain including an exacerbated response to seizures, increased CA1 neuron excitability, a pronounced weight gain and enhanced induction of immediate early genes (IEGs) in relevant neuronal nuclei. To identify candidate genes that could explain these phenotypes, we conducted two complementary genomic screens for the miRNAs primarily affected and their targets. Overall, our results explain both the initial and late consequences of Dicer loss in excitatory neurons and indicate that Dicer and the miRNA system play a critical role regulating neuronal homeostasis and responsiveness. Overall design: Hippocampal mRNA profiles of 3-month-old wild-type (WT) and Dicer-ifKO (3 weeks upon tamoxifen administration) male mice were generated by deep sequencing, in triplicate, using Illumina HiSeq 2500. Each sample included total RNA isolated from the hippocampus of 3 mice. In total, 12 mice per genotype were used.
Blocking miRNA Biogenesis in Adult Forebrain Neurons Enhances Seizure Susceptibility, Fear Memory, and Food Intake by Increasing Neuronal Responsiveness.
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View SamplesPurpose: The ability to rationally manipulate the transcriptional states of cells would be of great use in medicine and bioengineering. We have developed a novel algorithm, NetSurgeon, which utilizes genome-wide gene regulatory networks to identify interventions that force a cell toward a desired expression state. Results: We used NetSurgeon to select transcription factor deletions aimed at improving ethanol production in S. cerevisiae cultures that are catabolizing xylose. We reasoned that interventions that move the transcriptional states of cells utilizing xylose toward the fermentative state typical of cells that are producing ethanol rapidly (while utilizing glucose) might improve xylose fermentation. Some of the interventions selected by NetSurgeon successfully promoted a fermentative transcriptional state in the absence of glucose, resulting in strains with a 2.7-fold increase in xylose import rates, a 4-fold improvement in xylose integration into central carbon metabolism, or a 1.3-fold increase in ethanol production rate. Conclusions: We conclude by presenting an integrated model of transcriptional regulation and metabolic flux that will enable future metabolic engineering efforts aimed at improving xylose fermentation to prioritize functional regulators of central carbon metabolism. Overall design: Mutant and wildtype S. cerevisiae cells were put into 48 hour aerobic batch fermentations of synthetic complete medium supplmented with 2% glucose and 5% xylose and culture samples were taken at 4 hours and 24 hours for transcriptional profiling performed by RNA-Seq analysis. In addition, wildtype S. cerevisiae cells were grown in various single carbon sources for 12 hours and culture samples were taken for transcriptional profiling performed by RNA-Seq analysis.
Model-based transcriptome engineering promotes a fermentative transcriptional state in yeast.
Subject
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