This SuperSeries is composed of the SubSeries listed below.
Production of BMP4 by endothelial cells is crucial for endogenous thymic regeneration.
Sex, Specimen part
View SamplesThe thymus is extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood and this capacity diminishes considerably with age. To identify alternate regeneration pathways in the thymus, we performed an unbiased transcriptome analysis of the non-hematopoietic (CD45-) stromal cell compartment of the thymus, which is less sensitive to thymic damage compared to the CD45+ hematopoietic compartment.
Production of BMP4 by endothelial cells is crucial for endogenous thymic regeneration.
Sex, Specimen part
View SamplesThe thymus is extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood and this capacity diminishes considerably with age. To identify alternate regeneration pathways in the thymus, we performed an unbiased transcriptome analysis of the non-hematopoietic (CD45-) stromal cell compartment of the thymus, which is less sensitive to thymic damage compared to the CD45+ hematopoietic compartment.
Production of BMP4 by endothelial cells is crucial for endogenous thymic regeneration.
Sex, Specimen part
View SamplesBy investigating the germinal center (GC) formation in STAT6ko/WT bone marrow-mixed chimera we found that GC formation in type 2 immune responses is dependent on B cell intrinsic expression of IL-4/IL-13-induced genes. We therefore used microarrays to find Stat6 dependent genes that are important for germinal center formation and/or organization after infection with the nematode Nippostrongylus brasiliensis (N. brasiliensis).
B-cell-intrinsic STAT6 signaling controls germinal center formation.
Specimen part
View SamplesThe Polycomb group (PcG) gene products mediate heritable silencing of developmental regulators in metazoans, participating in one of two distinct multimeric protein complexes, the Polycomb repressive complexes-1 (PRC1) and -2 (PRC2). PRC2 catalyses trimethylation of histone H3 at lysine 27 (H3K27) which in turn is thought to provide a recruitment site for PRC1. Recent studies demonstrate that mono-ubiquitylation of histone H2A at lysine 119 is important in PcG mediated silencing with the core PRC1 component Ring1A/B functioning as the E3 ligase8. PRC2 has been shown to share target genes with the core transcription network to maintain embryonic stem (ES) cells including Oct4 and Nanog. Here we identify an essential role for PRC1 in repressing developmental regulators in ES cells, and thereby in maintaining ES cell pluripotency. A significant proportion of the PRC1 target genes are also repressed by Oct4. We demonstrate that engagement of PRC1 and PRC2 at target genes is Oct4-dependent and moreover that Ring1B interacts with Oct4. Collectively these results show that PcG complexes are instrumental in Oct4-dependent repression required to maintain pluripotency of ES cells. This study provides a first functional link between a core ES cell regulator and global epigenetic regulation of the genome.
Polycomb group proteins Ring1A/B are functionally linked to the core transcriptional regulatory circuitry to maintain ES cell identity.
No sample metadata fields
View SamplesThe Polycomb group (PcG) gene products mediate heritable silencing of developmental regulators in metazoans, participating in one of two distinct multimeric protein complexes, the Polycomb repressive complexes-1 (PRC1) and -2 (PRC2)1-5. PRC2 catalyses trimethylation of histone H3 at lysine 27 (H3K27) which in turn is thought to provide a recruitment site for PRC13-7. Recent studies demonstrate that mono-ubiquitylation of histone H2A at lysine 119 is important in PcG mediated silencing with the core PRC1 component Ring1A/B functioning as the E3 ligase8. PRC2 has been shown to share target genes with the core transcription network to maintain embryonic stem (ES) cells including Oct4 and Nanog9. Here we identify an essential role for PRC1 in repressing developmental regulators in ES cells, and thereby in maintaining ES cell pluripotency. A significant proportion of the PRC1 target genes are also repressed by Oct4. We demonstrate that engagement of PRC1 and PRC2 at target genes is Oct4-dependent and moreover that Ring1B interacts with Oct4. Collectively these results show that PcG complexes are instrumental in Oct4-dependent repression required to maintain pluripotency of ES cells. This study provides a first functional link between a core ES cell regulator and global epigenetic regulation of the genome.
Polycomb group proteins Ring1A/B are functionally linked to the core transcriptional regulatory circuitry to maintain ES cell identity.
No sample metadata fields
View SamplesThe Polycomb group (PcG) gene products mediate heritable silencing of developmental regulators in metazoans, participating in one of two distinct multimeric protein complexes, the Polycomb repressive complexes-1 (PRC1) and -2 (PRC2)1-5. PRC2 catalyses trimethylation of histone H3 at lysine 27 (H3K27) which in turn is thought to provide a recruitment site for PRC13-7. Recent studies demonstrate that mono-ubiquitylation of histone H2A at lysine 119 is important in PcG mediated silencing with the core PRC1 component Ring1A/B functioning as the E3 ligase8. PRC2 has been shown to share target genes with the core transcription network to maintain embryonic stem (ES) cells including Oct4 and Nanog9. Here we identify an essential role for PRC1 in repressing developmental regulators in ES cells, and thereby in maintaining ES cell pluripotency. A significant proportion of the PRC1 target genes are also repressed by Oct4. We demonstrate that engagement of PRC1 and PRC2 at target genes is Oct4-dependent and moreover that Ring1B interacts with Oct4. Collectively these results show that PcG complexes are instrumental in Oct4-dependent repression required to maintain pluripotency of ES cells. This study provides a first functional link between a core ES cell regulator and global epigenetic regulation of the genome.
Polycomb group proteins Ring1A/B are functionally linked to the core transcriptional regulatory circuitry to maintain ES cell identity.
No sample metadata fields
View SamplesInvasion of cytotrophoblasts into uterine tissues is essential for placental development. To identify molecules regulating trophoblast invasion, mRNA signatures of purified villous (CTB, poor invasiveness) and extravillous (EVT, high invasiveness) trophoblasts isolated from first trimester human placentae and villous explant cultures, respectively, were compared using GeneChip analyses yielding 991 invasion/migration related transcripts. Several genes involved in physiological and pathologic cell invasion, including ADAM-12,-19,-28 as well as Spondin-2, were upregulated in EVT. Pathway prediction analyses identified several functional modules associated with either the invasive or the non-invasive trophoblast phenotype. One of the genes which were downregulated in the invasive mRNA pool, heme oxygenase-1 (HO-1), was selected for functional analyses. Real-time PCR analyses, Western blottting, and immunofluorescene of first trimester placentae and differentiating villous explant cultures demonstrated downregulation of HO-1 in invasive EVT as compared to CTB. Modulation of HO-1 expression in loss-of as well as gain-of function cell models (BeWo and HTR8/SVneo, respectively) demonstrated an inverse relationship of HO-1 expression with trophoblast migration in transwell and wound healing assays. Importantly, HO-1 expression led to an increase in protein levels and activity of the nuclear hormone receptor PPARgamma. Pharmacological inhibition of PPARgamma abrogated the inhibitory effects of HO-1 on trophoblast migration. Collectively, our results demonstrate that gene expression profiling of EVT and CTB can be used to unravel novel regulators of cell invasion. Accordingly, we identify heme oxygenase-1 as a negative regulator of trophoblast motility acting via upregulation of PPARgamma.
Identification of novel trophoblast invasion-related genes: heme oxygenase-1 controls motility via peroxisome proliferator-activated receptor gamma.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Lamin B1 depletion in senescent cells triggers large-scale changes in gene expression and the chromatin landscape.
Specimen part, Cell line
View SamplesCellular senescence is a stable proliferation arrest in response to stress, associated with an altered secretory pathway (Senescence Associated Secretory Phenotype (SASP)). Senescence-associated proliferation arrest and the SASP are thought to act in concert to promote tumor suppression and tissue aging. While chromatin regulation and down regulation of lamin B1 have been implicated as effectors of cell senescence, functional interactions between them are poorly understood. We compared the genome-wide distributions of H3K4me3 and H3K27me3 between proliferating and senescent primary human cells and found dramatic differences, including large-scale domains of H3K4me3- and H3K27me3-enriched mesas and H3K27me3-depleted canyons in senescent cells. Senescent mesas form at the sites of lamin B1-associated domains (LADs) in proliferating cells. Mesas also overlap with regions that exhibit DNA hypomethylation in cancer, suggesting that chromatin changes in pre-malignant senescent cells foreshadow epigenetic changes in cancer. Proliferating fibroblasts from Hutchinson-Gilford Progeria Syndrome patients expressing mutant lamin A (progerin) also show evidence of H3K4me3 mesas, suggesting a link between premature chromatin changes and accelerated cell senescence and tissue aging. In contrast, canyons form mostly in between LADs and are enriched in genes, gene promoters and enhancers. Strikingly, H3K27me3 loss in canyons is correlated with upregulation of key senescence genes, including genes comprising the SASP, indicating a link between global changes in chromatin structure and local regulation of gene expression. Finally, premature reduction of lamin B1 in midlife proliferating cells triggers formation of senescence-associated mesas and canyons and accelerated senescence. Together, our data illustrate a profound reorganization of chromatin during senescence, and suggest that down regulation of lamin B1 in senescence is a key trigger of global and local chromatin changes that impact gene expression, aging and cancer.
Lamin B1 depletion in senescent cells triggers large-scale changes in gene expression and the chromatin landscape.
Specimen part, Cell line
View Samples