Upon antigen recognition within peripheral lymphoid organs, B cells interact with T cells and other immune cells to transiently form morphological structures called germinal centers (GCs), which are required for B cells clonal expansion, immunoglobulin class switching, and affinity maturation. This process, known as the GC response, is an energetically demanding process that requires metabolic reprogramming of B cells. Here, we showed that the Ras-related guanosine triphosphate hydrolase (GTPase) R-Ras2 (also known as TC21) plays an essential, nonredundant, and B cellintrinsic role in the GC response. Both the conversion of B cells into GC B cells and their expansion were impaired in mice lacking R-Ras2, but not in those lacking a highly-related R-Ras subfamily member or both the classic H-Ras and N-Ras GTPases. In the absence of R-Ras2, activated B cells did not increase oxidative phosphorylation or aerobic glycolysis. We showed that R-Ras2 was an effector of both the B cell receptor (BCR) and CD40 and that, in its absence, B cells exhibited impaired activation of the PI3K-Akt-mTORC1 pathway, reduced mitochondrial DNA replication, and decreased expression of genes involved in glucose metabolism. Because most human B cell lymphomas originate from GC B cells or B cells that have undergone the GC response, our data suggests that R-Ras2 may also regulate metabolism in B cell malignancies.
R-Ras2 is required for germinal center formation to aid B cells during energetically demanding processes.
Specimen part
View SamplesThe goal of the study was to characterize the molecular signatures of CD8 T cell subpopulations sorted from HIV+ lymph nodes and HIV- tonsils. We compared the transcriptome profiles of follicular and non -foliccular CD8 T cells (sorted based on the surface expression fo CCR7 and CXCR5, chemokine receptors that govern the intratissue trafficking of T cells). This is the first study addressing this question. We found several genes differentially expressed in these two CD8 T cell populations. Our pathway analysis revealed that several pathways related to costimulation/activation as well as to beta-catenin pathway were differentially expressed in these two CD8 t cell populations too. Overall design: CD8 T cell populations were sorted and whole transcriptome analysis was performed using an Illumina machine
Follicular CD8 T cells accumulate in HIV infection and can kill infected cells in vitro via bispecific antibodies.
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View SamplesTo study the effect of balanced chromosomal rearrangements on gene expression, we compared the transcriptomes of cell lines from control and t(11;22)(q23;q11) individuals. This translocation between chromosomes 11 and 22 is the only recurrent constitutional non-Robertsonian translocation in humans. The number of differentially expressed transcripts between the translocated and control cohort is significantly higher than that observed between control samples alone, suggesting that balanced rearrangements have a greater effect on gene expression than normal variation. Altered expression is not limited to genes close to the translocation breakpoint suggesting that a long-range effect is operating. Indeed we show that the nuclear position of the derivative chromosome is altered compared to the normal chromosomes. Our results are consistent with recent studies that indicate a functional role for nuclear position in regulating the expression of some genes in mammalian cells. They may also have implications on reproductive separation, as we show that reciprocal translocations not only provide partial isolation for speciation but also significant changes in transcriptional regulation through alteration of nuclear chromosomes territories.
The effect of translocation-induced nuclear reorganization on gene expression.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide profiling of methylation identifies novel targets with aberrant hypermethylation and reduced expression in low-risk myelodysplastic syndromes.
Specimen part
View SamplesGenome-wide expression and methylation profiling identifies novel targets with aberrant hypermethylation and reduced expression in low-risk myelodysplastic syndromes (MDSs).
Genome-wide profiling of methylation identifies novel targets with aberrant hypermethylation and reduced expression in low-risk myelodysplastic syndromes.
Specimen part
View SamplesThe identification of subtype-specific translocations has revolutionized diagnostics of sarcoma and provided new insight into oncogenesis. We used RNA-Seq to investigate samples diagnosed as small round cell tumors of bone, possibly Ewing sarcoma, but lacking the canonical EWSR1-ETS translocation. A new fusion was observed between the BCL6 co-repressor (BCOR) and the testis specific cyclin B3 (CCNB3) genes on chromosome X. RNA-Seq results were confirmed by RT-PCR and cloning the tumor-specific genomic translocation breakpoints. 24 BCOR-CCNB3-positive tumors were identified among a series of 594 sarcomas. Gene profiling experiments indicate that BCOR-CCNB3-positive cases are biologically distinct from other sarcomas, particularly Ewings sarcoma. Finally, we show that CCNB3 immunohistochemistry is a powerful diagnostic marker for this group of sarcoma and that over-expression of BCOR-CCNB3 or of a truncated CCNB3 activates S-phase in NIH3T3 cells. Thus the intrachromosomal X fusion described here represents a new subtype of bone sarcoma caused by a novel gene fusion mechanism.
A new subtype of bone sarcoma defined by BCOR-CCNB3 gene fusion.
Sex, Age, Specimen part
View SamplesThe iron chelator deferasirox is widely used in patients with iron overload. Patients with low-grade myelodysplastic syndromes (MDS) get transfusion dependency and need to be treated with deferasirox to avoid iron overload. Moreover, in some patients an increase in both erythroid and platelets have been observed after deferasirox therapy. However, the mechanisms involved in these clinical findings are poorly understood. The aim of this work was to analyze, in patients treated with deferasirox, the changes in the gene expression profile after receiving the treatment. A total of fifteen patients with the diagnosis of low-grade MDS were studied. Microarrays were carried out in RNA from peripheral blood before and after 14 weeks of deferasirox therapy. Changes in 1,457 genes and 54 miRNAs were observed: deferasirox induced the downregulation of genes related to the Nf kB pathway leading of an overall inactivation of this pathway. In addition, the iron chelator also downregulated gamma interferon. Altogether these changes could be related to the improvement of erythroid response observed in these patients after therapy. Moreover, the inhibition of NFE2L2/ NRF2, which was predicted in silico, could be playing a critical role in the reduction of reactive oxygen species (ROS). Of note, miR-125b, overexpressed after deferasirox treatment, could be involved in the reduced inflammation and increased hematopoiesis observed in the patients after treatment. In summary this study shows, for the first time, the mechanisms that could be governing deferasirox impact in vivo.
Genome-wide transcriptomics leads to the identification of deregulated genes after deferasirox therapy in low-risk MDS patients.
Specimen part, Disease, Treatment, Subject
View SamplesTo get insight in the functional role of EGR2 for Ewing sarcoma, we performed a transcriptional profiling of Ewing sarcoma cells after knockdown of EGR2 and compared the resulting transcriptional signature with that of EWSR1-FLI1-silenced Ewing sarcoma cells. In accordance with the strong EGR2-induction by EWSR1-FLI1, both genes highly significantly overlap in their transcriptional signatures. Gene-set enrichment analyses (GSEA) and DAVID (Database for Annotation, Visualisation and Integrated Discovery) gene ontology analyses indicated a strong impact of EGR2 on cholesterol and lipid biosynthesis resembling its function in orchestrating lipid metabolism of myelinating Schwann cells.
Chimeric EWSR1-FLI1 regulates the Ewing sarcoma susceptibility gene EGR2 via a GGAA microsatellite.
Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Medullary Breast Carcinoma, a Triple-Negative Breast Cancer Associated with BCLG Overexpression.
Disease, Disease stage
View SamplesGene expression was compared between medullary breast carcinoma (MBC) and non medullary basal-like breast carcinoma (non-MBC BLC).
Medullary Breast Carcinoma, a Triple-Negative Breast Cancer Associated with BCLG Overexpression.
Disease, Disease stage
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