Global, genomic responses of erythrocytes to infectious agents have been difficult to measure, because these cells are e-nucleated. We have previously demonstrated that in vitro matured, nucleated erythroblast cells at the orthochromatic stage can be efficiently infected by the human malaria parasite Plasmodium falciparum. We now show that infection of orthochromatic cells induces change in 609 host genes. 592 of these transcripts are up-regulated and associated with metabolic and chaperone pathways unique to P. falciparum infection, as well as a wide range of signaling pathways that are also induced in related apicomplexan infections of mouse hepatocytes or human fibroblast cells. Our data additionally show that polychromatophilic cells, which precede the orthochromatic stage and are not infected when co-cultured with P. falciparum, up-regulate a small set of 35 genes, 9 of which are associated with pathways of hematopoiesis and/or erythroid cell development. These data unexpectedly predict that blood stage P. falciparum may induce host responses common to infections of other pathogens. Further P. falciparum may modulate gene expression in bystander erythroblasts and thus influence pathways of erythrocyte development.
P. falciparum modulates erythroblast cell gene expression in signaling and erythrocyte production pathways.
Specimen part
View SamplesIdentification of genes regulated by GATA-1 independent of the cofactor FOG-1.
Friend of GATA-1-independent transcriptional repression: a novel mode of GATA-1 function.
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View SamplesDifferentiating erythroid cells execute a unique gene expression program that insures synthesis of the appropriate proteome at each stage of maturation. Standard expression microarrays provide important insight into erythroid gene expression, but cannot detect qualitative changes in transcript structure, mediated by RNA processing, that alter structure and function of encoded proteins. We analyzed stage-specific changes in the late erythroid transcriptome via use of high resolution microarrays that detect altered expression of individual exons. Ten differentiation-associated changes in erythroblast splicing patterns were identified, including the previously known activation of protein 4.1R exon 16 splicing. Six new alternative splicing switches involving enhanced inclusion of internal cassette exons were discovered, as well as three changes in use of alternative first exons. All of these erythroid stage-specific splicing events represent activated inclusion of authentic annotated exons, suggesting they represent an active regulatory process rather than a general loss of splicing fidelity. The observation that three of the regulated transcripts encode RNA binding proteins (SNRP70, HNRPLL, MBNL2) may indicate significant changes in the RNA processing machinery of late erythroblasts. Together these results support the existence of a regulated alternative pre-mRNA splicing program that is critical for late erythroid differentiation.
Alternative pre-mRNA splicing switches modulate gene expression in late erythropoiesis.
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View SamplesTropomodulins (Tmods) cap the pointed ends of actin filaments in erythroid and nonerythoid cell types. Targeted deletion of mouse Tmod3 leads to embryonic lethality at E14.5-E18.5, with anemia due to defects in definitive erythropoiesis in the fetal liver. BFU-E and CFU-E colony numbers are greatly reduced, indicating defects in progenitor populations. Flow-cytometry of fetal liver erythroblasts shows late stage populations are also decreased, including reduced percentages of enucleated cells. AnnexinV staining indicates increased apoptosis of Tmod3-/- erythroblasts, and cell cycle analysis reveals that there are more Ter119hi cells in S-phase in Tmod3-/- embryos. Notably, enucleating Tmod3-/- erythroblasts are still in the process of proliferation, suggesting impaired cell cycle exit during terminal differentiation. Tmod3-/- late erythroblasts often exhibit multi-lobular nuclear morphologies and aberrant F-actin assembly during enucleation. Furthermore, native erythroblastic island formation was impaired in Tmod3-/- fetal livers, with Tmod3 required in both erythroblasts and macrophages. In conclusion, disruption of Tmod3 leads to impaired definitive erythropoiesis, due to reduced progenitors, impaired erythroblastic island formation, and defective erythroblast cell cycle progression and enucleation. Tmod3-mediated actin remodeling may be required for erythroblast-macrophage adhesion, coordination of cell cycle with differentiation, and F-actin assembly and remodeling during erythroblast enucleation.
Tropomodulin3-null mice are embryonic lethal with anemia due to impaired erythroid terminal differentiation in the fetal liver.
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View SamplesAlthough the cytokine-inducible transcription factors STAT5a/b promote proliferation of a wide range of cell types, there are cell- and context specific cases in which loss of STAT5a/b results in enhanced cell proliferation. Here we report that loss of STAT5a/b from mouse embryonic fibroblasts (MEFs) leads to enhanced proliferation, which was linked to reduced levels of the cell cycle inhibitor p15INK4B and p21CIP1. We further demonstrate that growth hormone through the transcription factor STAT5a/b enhances expression of the cdkn2B gene and that STAT5a binds to GAS sites within the promoter. We have recently demonstrated that ablation of STAT5a/b from liver results in hepatocellular carcinoma upon a CCl4 insult. We also established that in liver tissue, like in MEFs, STAT5a/b activates expression of the cdkn2B gene. Loss of STAT5a/b led to diminished p15INK4B and increased hepatocyte proliferation. This study for the first time demonstrates that cytokines through STAT5a/b can induce the expression of a key cell cycle inhibitor. These experiments therefore shed a light on the context-specific role of STAT5a/b as tumor suppressors.
The transcription factors signal transducer and activator of transcription 5A (STAT5A) and STAT5B negatively regulate cell proliferation through the activation of cyclin-dependent kinase inhibitor 2b (Cdkn2b) and Cdkn1a expression.
Specimen part
View SamplesGM-CSF controls the development of granulocytes but little is known about the contribution of the downstream mediating transcription factor STAT5A/B. To elucidate this pathway, we generated mice lacking the Stat5a and 5b genes in blood cells. Peripheral neutrophils were decreased and administration of 5-FU and GM-CSF failed to induce granulopoiesis in Stat5a/b-mutant mice. GMPs were isolated and cultured with GM-CSF. Both the number and size of STAT5A/B-null colonies were reduced and GM-CSF-induced survival of mature STAT5A/B-null neutrophils was impaired. Time-lapse cinematography and single cell tracking of GMPs revealed that STAT5A/B-null cells were characterized by a longer generation time and an increased cell death. Gene expression profiling experiments suggested that STAT5A/B directs GM-CSF signaling through the regulation of cell survival genes.
The transcription factors STAT5A/B regulate GM-CSF-mediated granulopoiesis.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptional blood signatures distinguish pulmonary tuberculosis, pulmonary sarcoidosis, pneumonias and lung cancers.
Sex, Specimen part, Disease, Disease stage, Treatment, Race, Subject
View SamplesThis study used whole blood transcriptional signatures from patients with tuberculosis compared to those with similar pulmonary diseases, sarcoidosis, pneumonia and primary lung cancer. TB and sarcoidosis had similar signatures that were distinct from pneumonia and lung cancer.
Transcriptional blood signatures distinguish pulmonary tuberculosis, pulmonary sarcoidosis, pneumonias and lung cancers.
Sex, Specimen part, Disease, Disease stage, Race
View SamplesCD34 positive hematopoietic stem cells were differentiated into erythroid lineage. Next generation sequencing (NGS) of 5hmC affinity pulldown and RNAseq were performed in four time point of different stages of erythroid differentiation. Overall design: 4 RNA-Seq Samples (d0, d3, d7 and d10); 4 affinity-pulldown (d0, d3, d7 and d10), and 4 input samples (d0, d3, d7 and d10).
Hydroxymethylation at gene regulatory regions directs stem/early progenitor cell commitment during erythropoiesis.
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View SamplesBackground: Breastfed human infants are predominantly colonized by bifidobacteria that thrive on human milk oligosaccharides (HMO). The two most predominant species of bifidobacteria in infant feces are Bifidobacterium breve (B. breve) and Bifidobacterium longum subsp. infantis (B. infantis), both avid HMO-consumer strains. Our laboratory has previously shown that B. infantis, when grown on HMO, increase adhesion to intestinal cells and increase the expression of the anti-inflammatory cytokine interleukin-10. The purpose of the current study was to investigate the effects of carbon source—glucose, lactose, or HMO—on the ability of B. breve and B. infantis to adhere to and affect the transcription of intestinal epithelial cells on a genome-wide basis. Results: HMO-grown B. infantis had higher percent binding to Caco-2 cell monolayers compared to B. infantis grown on glucose or lactose. B. breve had low adhesive ability regardless of carbon source. Despite differential binding ability, both HMO-grown strains significantly differentially affected the Caco-2 transcriptome compared to their glucose or lactose grown controls. HMO-grown B. breve and B. infantis both down-regulated genes in Caco-2 cells associated with chemokine activity. Conclusion: The choice of carbon source affects the interaction of bifidobacteria with intestinal epithelial cells. HMO-grown bifidobacteria reduce markers of inflammation, compared to glucose or lactose-grown bifidobacteria. In the future, the design of preventative or therapeutic probiotic supplements may need to include appropriately chosen prebiotics. Overall design: CACO-2 cells incubated with Bifidobacterium longum subsp. infantis grown on (1) glucose, (2) lactose, or (3) human milk oligosaccharides. All experiments were run in triplicate.
Bifidobacteria grown on human milk oligosaccharides downregulate the expression of inflammation-related genes in Caco-2 cells.
No sample metadata fields
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