Chronic Lymphocytic Leukemia (CLL) cells multiply in secondary lymphoid tissue but the mechanisms leading to their proliferation are still uncertain. In addition to BCR-triggered signals, other microenvironmental factors might well be involved. In proliferation centres, leukemic B cells are in close contact with CD4+CD40L+T cells. Therefore, we here dissected the signals provided by autologous activated T cells (Tact) to CLL cells. Although the gene expression profile induced by Tact was highly similar to that induced by sole CD40 signaling, an obvious difference was that Tact induced proliferation of CLL cells. We determined that stimulation with only CD40L+IL-21 was sufficient to induce robust proliferation in CLL cells. We then defined an IL-21-induced gene signature in CLL, containing components of JAK-STAT and apoptosis pathways, and this signature could be detected in lymph node (LN) samples from patients. Finally, we could detect IL-21 RNA and protein in LN, and IL-21 productionex vivoby LN CD4+CXCR5+ follicular helper T cells. These results indicate that, in addition to BCR signaling, activated T cells might contribute to CLL cell proliferation via CD40 and IL-21. Targeting these signaling pathways might offer new venues for treatment of CLL.
IL-21 and CD40L signals from autologous T cells can induce antigen-independent proliferation of CLL cells.
Specimen part, Treatment
View SamplesProtective interactions with bystander cells in micro-environmental niches such as lymph nodes (LNs) contribute to survival and therapy resistance of chronic lymphocytic leukemia (CLL) cells. This is caused by a shift in expression of BCL-2 family members. Pro-survival proteins BCL-XL, BFL-1, and MCL-1 are upregulated by LN-residing T cells through CD40L interaction, presumably via NF-B signaling. Macrophages also reside in the LN, and are assumed to provide important supportive functions for CLL cells. However, if and how macrophages are able to induce survival is incompletely known. We first established that macrophages induced survival due to an exclusive upregulation of MCL-1. Next, we investigated the mechanism underlying MCL-1 induction by macrophages in comparison with CD40L. Genome-wide expression profiling of in vitro macrophage- and CD40L-stimulated CLL cells indicated activation of the PI3K-AKT-mTOR pathway, which was confirmed in ex vivo CLL LN material. Inhibition of PI3K-AKT-mTOR signaling abrogated MCL-1 upregulation and survival by macrophages as well asCD40 stimulation. MCL-1 can be regulated at multiple levels, and we established that AKT leads to increased MCL-1 translation, but does not affect MCL-1 transcription or protein stabilization. Furthermore, among macrophage-secreted factors that could activate AKT, we found that induction of MCL-1 and survival critically depended on C-C Motif Chemokine Receptor-1 (CCR1). In conclusion, this study indicates that two distinct micro-environmental factors, CD40L and macrophages, signal via CCR1 to induce AKT activation resulting in translational stabilization of MCL-1, and hence can contribute to CLL cell survival.
Macrophages confer survival signals via CCR1-dependent translational MCL-1 induction in chronic lymphocytic leukemia.
Specimen part, Disease stage
View SamplesThe NuRD complex is generally thought to repress transcription at both hyper- and hypomethylated regions in the genome. In addition, the complex is involved in the DNA damage response. Here, we show that ZMYND8 bridges NuRD to a number of putative DNA-binding zinc finger proteins. The ZMYND8 MYND domain directly interacts with PPPL? motifs in the NuRD subunit GATAD2A. Furthermore, GATAD2A and GATAD2B exclusively form homodimers and they thus define mutually exclusive NuRD subcomplexes. ZMYND8 and MBD3 share a large number of genome-wide binding sites, mostly active promoters and enhancers. Depletion of ZMYND8 does not affect NuRD occupancy genome-wide and expression of NuRD/ZMYND8 target genes in steady-state asynchronous cells. However, ZMYND8 facilitates immediate recruitment of GATAD2A/NuRD to induced sites of DNA damage. These results thus show that a specific substoichiometric interaction with a NuRD subunit paralogue provides unique functionality to a distinct NuRD subcomplex. Overall design: RNA-seq samples for HeLa FRT-TO mock, ZMYND8KO, and ZMYND8KO-rescue cells
ZMYND8 Co-localizes with NuRD on Target Genes and Regulates Poly(ADP-Ribose)-Dependent Recruitment of GATAD2A/NuRD to Sites of DNA Damage.
Subject
View SamplesThe splicing factor SF3B1 is the most commonly mutated gene in the myelodysplastic syndromes (MDS), particularly in patients with refractory anemia with ring sideroblasts (RARS). MDS is a disorder of the hematopoietic stem cell and we thus studied the transcriptome of CD34+ cells from MDS patients with SF3B1 mutations using RNA-sequencing. Genes significantly differentially expressed at the transcript and/or exon level in SF3B1 mutant compared to wildtype cases include genes involved in MDS pathogenesis (ASXL1, CBL), iron homeostasis and mitochondrial metabolism (ALAS2, ABCB7, SLC25A37) and RNA splicing/processing (PRPF8, HNRNPD). Many genes regulated by a DNA damage-induced BRCA1-BCLAF1-SF3B1 protein complex showed differential expression/splicing in SF3B1 mutant cases. Our data indicate that SF3B1 plays a critical role in MDS by affecting the expression and splicing of genes involved in specific cellular processes/pathways, many of which are relevant to the known RARS pathophysiology, suggesting a causal link. Overall design: RNA-Seq was performed to compare the transcriptome of bone marrow CD34+ cells from eight MDS patients with SF3B1 mutation, four MDS patients with no known splicing mutation and five healthy controls.
Disruption of SF3B1 results in deregulated expression and splicing of key genes and pathways in myelodysplastic syndrome hematopoietic stem and progenitor cells.
No sample metadata fields
View SamplesWe investigated transcriptional changes in CD4CD8aa and CD4 intraepthelial lymphocytes.
Transcriptional reprogramming of mature CD4⁺ helper T cells generates distinct MHC class II-restricted cytotoxic T lymphocytes.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Epigenetic chromatin states uniquely define the developmental plasticity of murine hematopoietic stem cells.
Specimen part
View SamplesAn investigation of the global gene expression signatures of murine hematopoietic stem cell differentiation during steady state hematopoiesis.
Epigenetic chromatin states uniquely define the developmental plasticity of murine hematopoietic stem cells.
Specimen part
View SamplesThe major myeloid blood cell lineages, including erythrocytes, platelets, granulocytes and macrophages, are generated from hematopoietic stem cells (HSC) by differentiation through a series of increasingly more committed progenitor cells. Precise phenotypic identification and functional characterization of such intermediate progenitors has important consequences for understanding fundamental differentiation processes and is clinically relevant since such events become dysregulated in various disease settings, including leukemia. While previous studies have suggested a hierarchy for myeloid differentiation involving a common progenitor through which all myeloid lineages are derived, several recent studies have suggested that such a developmental intermediate might not be an absolute requirement. Here, we evaluated the functional in vitro and in vivo potentials of a range of prospectively isolated myeloid precursors with differential expression of CD150, Endoglin and CD41. Our studies reveal a complex hierarchy of myeloerythroid progenitors with distinct and developmentally restricted lineage potentials. Global gene expression signatures of these cellular subsets revealed expression patterns consistent with their functional capacities, while hierarchical clustering analysis provides details on their lineage relationships. These data challenge existing models of hematopoietic differentiation, by suggesting that progenitors of the innate and adaptive immune system in the adult separate late, and to a large extent, following the divergence of megakaryocytic/erythroid potential.
Elucidation of the phenotypic, functional, and molecular topography of a myeloerythroid progenitor cell hierarchy.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Chromatinized protein kinase C-θ directly regulates inducible genes in epithelial to mesenchymal transition and breast cancer stem cells.
Cell line, Treatment
View SamplesEpithelial to mesenchymal transition (EMT) is activated during cancer invasion and metastasis, enriches for cancer stem cells (CSCs), and contributes to therapeutic resistance and disease recurrence. The epithelial cell line MCF7, can be induced to undergo EMT with the induction of PKC by PMA. 5-10% of the resulting cells have a CSC phenotype. This study looks at the transcriptome of these cells and how it differs from cells with a non-CSC phenotype.
Chromatinized protein kinase C-θ directly regulates inducible genes in epithelial to mesenchymal transition and breast cancer stem cells.
Cell line, Treatment
View Samples