Toxoplasma gondii is a ubiquitous apicomplexan parasite of mammals and birds and an important pathogen of humans. IFN-g is the major mediator of host resistance against T. gondii but intriguingly, parasite-infected host cells including macrophages are severely impaired to respond to IFN-g due to defective transcriptional activation of target genes. Here, we tested the possibility that the impaired responsiveness of T. gondii-infected macrophages to IFN-g can be restored by inhibiting histone deacetylases (HDACs) using the class I-specific inhibitor MS-275. Treatment of RAW264.7 cells with MS-275 indeed increased MHC class II surface expression in infected and non-infected cells and largely abolished the inhibition of IFN-g-regulated MHC class II expression exerted by T. gondii. Genome-wide transcriptome profiling revealed that MS-275 increased mean mRNA levels of IFN-g-regulated genes particularly in non-infected macrophages. Transcript levels of 33% of IFN-g secondary response genes but only those of a few primary response genes were also increased by MS-275 in T. gondii-infected cells. Importantly, the unresponsiveness of parasite-infected cells to IFN-g was however not abolished by MS-275. Furthermore, MS-275 also up-regulated several anti-inflammatory cytokines or signaling molecules in T. gondii-infected macrophages. It additionally regulated expression of more than 2500 genes in non-infected macrophages expression of which was surprisingly counteracted by prior infection with T. gondii. FACS analysis and immunofluorescence microscopy revealed that MS-275 did not considerably diminish the number of parasite-positive cells or the intracellular replication in macrophages stimulated or not with IFN-g. Thus, a supportive therapy using MS-275 appears inappropriate for treatment of toxoplasmosis. Overall design: High throughput RNA profiles from IFN-g-activated monocytic cells infected with Toxoplasma gondii and treated with MS-275 and control cells were generated by Illumina sequencing. Five experimental conditions with 2 biological replicates each were analysed.
Histone deacetylase inhibitor MS-275 augments expression of a subset of IFN-γ-regulated genes in Toxoplasma gondii-infected macrophages but does not improve parasite control.
Subject
View SamplesTrancript Based Cloning (TBC) uses standard Gene Expression techniques to quickly isolate genes of interest and begin to determine their function. Using a particular mutant phenotype, identified during a programme of mutagenesis and screning, and a wild-type control we can quickly determine a list of genes that is likely to contain the gene responsible for the phenotype. TBC is a general method for identifying and cloning important plant genes that is fast and may be applicable to almost any plant species Transcript abundance assays on the barley rar1-2 mutant and Sultan5 wild type were performed by using standard methods for the Affymetrix barley genome array (Affymetrix). For each genotype, two independent biological replicates were analyzed and pooled for analysis. Data were analyzed with DCHIP VERSION 1.3 (www.dchip.org),using data from only perfect-match oligonucleotides. Model-based analysis was performed by using perfect match-only analysis, compiling data from two biological replicates for each condition. Pairwise comparisons were analyzed for each condition, and a lower 90% confidence bound (LCB) and fold change were determined for each comparison. Gene expression changes were considered significant if the LCB was 1.4-fold or higher and if the intensities between the two conditions differed by >100. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, james hadfield. The equivalent experiment is BB5 at PLEXdb.]
A Ca2+/calmodulin-dependent protein kinase required for symbiotic nodule development: Gene identification by transcript-based cloning.
Specimen part
View SamplesRelative levels of RNA transcripts were compared between anterior and posterior wing bud thirds from stage HH24 normal and talpid3 mutant chicken embryos using chicken Affymetrix chips. Data collected with Affymetrix scanner was normalized using the Plier algorithm within the expression console package from Affymetrix and log2 transformed. 5 replicates of anterior third normal wing buds, 4 replicates of posterior third of normal wing buds and 4 replicates each of anterior and posterior thirds of talpid3 wing buds at stage HH24 were examined.
Identification of genes downstream of the Shh signalling in the developing chick wing and syn-expressed with Hoxd13 using microarray and 3D computational analysis.
Age, Specimen part
View SamplesThe post-transcriptional control of mRNA stability plays a critical role in numerous biological functions, including the immune response, cell cycle regulation and DNA damage response. HNRNPA0, which encodes an RNA-binding protein shown to regulate transcript stability via binding to the AU-rich elements (AREs) of mRNAs, is located within the commonly deleted segment of 5q31.2 in therapy-related myeloid neoplasms (t-MNs) with a del(5q). We hypothesized that loss of HNRNPA0 leads to alterations in hematopoietic differentiation due to changes in the expression of its target AU-rich transcripts. Using RNAi interference to model Hnrnpa0 loss in primary murine cells and an experimental cell system, we found that reduced Hnrnpa0 expression leads to a shift from monocytic towards granulocytic differentiation. Microarray-based global expression profiling revealed that Hnrnpa0 knockdown disproportionally impacts ARE-containing transcripts and alters expression of myeloid specification genes. The biological importance of ARE-containing genes in myeloid neoplasms is further supported by changes in gene expression of ARE-mRNAs in t-MN del(5q) patients, predicted by pathway analysis to activate tumor growth. Together, our findings suggest that alterations in ARE-containing genes can positively regulate the cellular proliferation of del(5q) cells and implicate haploinsufficiency of HNRNPA0 as one of the key initiation mutations in the pathogenesis of t-MN.
Knockdown of Hnrnpa0, a del(5q) gene, alters myeloid cell fate in murine cells through regulation of AU-rich transcripts.
Specimen part, Disease, Disease stage
View SamplesRNAseq analysis of caecal tissue from 14 C. jejuni-susceptible and 14 C. jejuni-resistant birds from a single population of infected chickens was conducted in order to identify gene expression associated with resistance to colonization. Significantly higher expression of genes involved in the innate immune response, cytokine signaling, B cell and T cell activation and immunoglobulin production, as well as the renin-angiotensin system was observed in resistant birds. Overall design: A population of 255 Barred Rock chickens were orally inoculated with C. jejuni and their caecal colonization levels estimated 48 hours post-inoculation. Caecal samples from 14 birds with no colonization and the 14 birds with the highest colonization were selected for mRNA sequencing.
Genome-wide association analysis of avian resistance to Campylobacter jejuni colonization identifies risk locus spanning the CDH13 gene.
Specimen part, Subject
View SamplesAcute lymphoblastic leukemia (ALL), the commonest childhood malignancy, is characterized by recurring gross and submicroscopic structural genetic alterations that contribute to leukemogenesis. Disordered epigenetic regulation is a hallmark of many tumors, and while analysis of DNA methylation of limited numbers of genes or ALL samples suggests epigenetic alterations may also be important, a large-scale integrative genome-wide analysis evaluating DNA methylation in ALL has not been performed. Here, we report an integrated epigenomic, transcriptional and genetic analysis of 167 childhood ALL cases, comprising B-progenitor ALL with hyperdiploidy (N=26), ETV6-RUNX1 (N=27), TCF3-PBX1 (N=9), BCR-ABL1 (N=19), rearrangement of MLL (MLLr) (N=20), rearrangement of CRLF2 (N=11, CRLF2r), deletion of ERG (N=11), miscellaneous or normal karyotype (N=14), and T-lineage ALL (N=30), including 4 MLLr cases and 7 cases with early T-cell precursor immunophenotype. Genome-wide profiling of structural DNA alterations was performed for all cases using Affymetrix 500K and SNP 6.0 arrays. Affymetrix U133A gene expression profiling data was available for 154 cases. Genome-wide methylation profiling was performed using the HELP microarray assay, which measures methylation at approximately 50,000 CpGs distributed among 22,722 Refseq promoters. Methylation data was compared to that of normal pro-B (CD34+CD19+sIg-), pre-B (CD34-CD19+sIg-) and mature B (CD34-CD19+sIg+) cells FACS-sorted from bone marrow of 6 healthy individuals. Unsupervised hierarchical clustering of the top 4043 most variable methylation probesets identified 9 B-ALL clusters with significant correlation to specific genetic lesions including ETV6-RUNX1, MLLr, BCR-ABL1, CRLF2r, TCF3-PBX1 and ERG deletion. T-ALLs and hyperdiploid B-ALLs also defined specific DNA methylation clusters. Supervised analysis including limma and ANOVA identified distinct DNA methylation signatures for each subtype. Notably, the strength of these signatures was subtype dependent, with more differentially methylated genes observed in ALL cases with genetic alterations targeting transcriptional regulators (e.g. ETV6-RUNX1 and MLLr) and fewer genes in cases with alterations deregulating cytokine receptor signaling (e.g. CRLF2r). Aberrant DNA methylation affected specific and distinct biological processes in the various leukemia subtypes implicating epigenetic regulation of these pathways in the pathogenesis of these different forms of ALL (e.g. TGFB and TNF in ERG deleted leukemias; telomere and centriole regulation in BCR-ABL1 ALL). Aberrantly methylated genes were also enriched for binding sites of known or suspected oncogenic transcription factors that might represent cooperative influences in establishing the phenotype of the various B-ALL subtypes. Most importantly, an integrated analysis of methylation and gene expression of these ALL subtypes demonstrated striking inversely correlated expression of the corresponding gene transcripts. The methylation signatures of each subtype exhibited only partial overlap with those of normal B cells, indicating that the signatures do not simply reflect stage of lymphoid maturation. In a separate approach, we discovered that 81 genes showed consistent aberrant methylation across all ALL subtypes, including the tumor suppressor PDZD2, HOXA5, HOXA6 and MSH2. Inverse correlation with expression was confirmed in 66% of these genes. These data suggest the existence of a common epigenetic pathway underlying the malignant transformation of lymphoid precursor cells. Integrative genetic and epigenetic analysis revealed hypermethylation of genes on trisomic chromosomes that do not show increased expression, suggesting that epigenetic silencing may control genes within amplified regions and explain why only selected genes are overexpressed. Finally, analysis of individual genes targeted by recurring copy number alterations in ALL revealed a subset of genes also targeted by abnormal methylation, with corresponding changes in gene expression (e.g. ERG, GAB1), suggesting that such genes are inactivated far more frequently than suggested by genetic analyses alone. Collectively, the data support a key role of epigenetic gene regulation in the pathogenesis of ALL, and point towards a scenario where genetic and epigenetic lesions cooperatively determine disease phenotype.
Integrated genetic and epigenetic analysis of childhood acute lymphoblastic leukemia.
Specimen part
View SamplesContemporary treatment of pediatric acute myeloid leukemia (AML) requires the assignment of patients to specific risk groups. To explore whether expression profiling of leukemic blasts could accurately distinguish between the known risk groups of AML, we analyzed 130 pediatric and 20 adult AML diagnostic bone marrow or peripheral blood samples using the Affymetrix U133A microarray. Class discriminating genes were identified for each of the major prognostic subtypes of pediatric AML, including t(15;17)[PML-RARalpha], t(8;21)[AML1-ETO], inv(16) [CBFbeta-MYH11], MLL chimeric fusion genes, and cases classified as FAB-M7. When subsets of these genes were used in supervised learning algorithms, an overall classification accuracy of more than 93% was achieved. Moreover, we were able to use the expression signatures generated from the pediatric samples to accurately classify adult de novo AMLs with the same genetic lesions. The class discriminating genes also provided novel insights into the molecular pathobiology of these leukemias. Finally, using a combined pediatric data set of 130 AMLs and 137 acute lymphoblastic leukemias, we identified an expression signature for cases with MLL chimeric fusion genes irrespective of lineage. Surprisingly, AMLs containing partial tandem duplications of MLL failed to cluster with MLL chimeric fusion gene cases, suggesting a significant difference in their underlying mechanism of transformation. All the gene expression arrays are available through http://www.stjuderesearch.org/site/data/AML1/ in the original study (PMID:15226186). To study the RAS gene expression in the human AML patients, a total of 104 AML cases with known KRAS and NRAS status (including 72 gene expression arrays in the original study and 32 additional arrays acquired later on), as well as 4 CD34+ normal bone marrow cases deposited in GEO GSE33315, were including in this depository.
Dominant role of oncogene dosage and absence of tumor suppressor activity in Nras-driven hematopoietic transformation.
Disease, Disease stage
View SamplesThe oncogenic proteins expressed in human cancer cells are exceedingly difficult targets for drug discovery due to intrinsic properties of the Ras GTPase switch. As a result, recent efforts have largely focused on inhibiting Ras-regulated kinase effector cascades, particularly the Raf/MEK/ERK and PI3 kinase/Akt/mTOR pathways. We constructed murine stem cell leukemia virus (MSCV) vectors encoding oncogenic K-RasD12 with additional second site amino acid substitutions that that impair PI3 kinase/Akt or Raf/MEK/ERK activation and performed bone marrow transduction/transplantation experiments in mice. In spite of attenuated signaling properties, defective K-Ras oncoproteins induced aggressive clonal T lineage acute lymphoblastic leukemia (T-ALL). These leukemias exhibited a high frequency of somatic Notch1 mutations, which is also true of human T-ALL. Multiple independent T-ALLs restored full oncogenic Ras activity by acquiring third site mutations within the viral KrasD12 transgenes. Other leukemias with undetectable PTEN and elevated phosphoryated Akt levels showed a similar gene expression profile to human early T progenitor (ETP) T-ALL. Expressing oncoproteins that are defective for specific functions is a general strategy for assessing requirements for tumor maintenance and uncovering potential mechanisms of drug resistance in vivo. In addition, our observation that defective Kras oncogenes regain potent cancer initiating activity strongly supports simultaneously targeting distinct components of Ras signaling networks in the substantial fraction of cancers with RAS mutations.
Defective K-Ras oncoproteins overcome impaired effector activation to initiate leukemia in vivo.
Specimen part, Cell line
View SamplesNormal myeloid lineage cell populations (C57BL/6 mice, aged 4-10 weeks, male or female) with three distinct immunophenotypes were prospectively isolated and characterized. In preparation for FACS sorting, bone marrow cells were separated into c-kit+ and c-kit- fractions using an AutoMACS device. C-kit+ cells were further fractionated based on Gr1 and Mac1 expression, and absence of lineage antigen expression (B220, TER119, CD3, CD4, CD8 and IL7R), by cell sorting. C-kit+ Gr1+ Mac1lo/- and c-kit+ Gr1+ Mac1+ displayed cytologic features of undifferentiated hematopoietic cells or myeloblasts, whereas c-kit- Gr1+ Mac1+ cells were mature neutrophils.
Hierarchical maintenance of MLL myeloid leukemia stem cells employs a transcriptional program shared with embryonic rather than adult stem cells.
No sample metadata fields
View SamplesLeukemia cells from mice with MLL-AF10 AML were fractionated into separate sub-populations on the basis of c-kit expression, which correlates with MLL LSC frequency (Somervaille and Cleary, 2006). The sorted AML sub-populations exhibited substantial differences in their frequencies of AML CFCs/LSCs (mean 14-fold) and morphologic features, consistent with a leukemia cell hierarchy with maturation through to terminally differentiated neutrophils.
Hierarchical maintenance of MLL myeloid leukemia stem cells employs a transcriptional program shared with embryonic rather than adult stem cells.
No sample metadata fields
View Samples