Rheumatoid arthritis is an inflammatory disease of the synovial joints that affects ~1% of the human population, with severe distress due to progressive joint inflammation and deformation. When addressing the links between specific components of the apoptotic cell clearance machinery and human disease, we noted a correlation between single nucleotide polymorphisms (SNPs) in ELMO1, DOCK2, and RAC1 genes and rheumatoid arthritis. ELMO1 is a cytoplasmic adapter protein that associates with DOCK2 and RAC1 to promote cytoskeletal reorganization needed for apoptotic cell uptake by phagocytes. We initially hypothesized that, since ELMO1 is linked to apoptotic cell clearance, loss of ELMO1 would lead to increased inflammation in arthritis. Contrary to the accumulation of apoptotic cells and greater disease severity that we predicted, we observed significantly reduced joint inflammation in two models of arthritis in mice lacking ELMO1. Using genetic and cell biological approaches in vivo and ex vivo, we determined that ELMO1 deficiency significantly reduces neutrophil recruitment to inflamed joints, but does not result in general inhibition of inflammatory responses. Through proteomic analyses, we find that ELMO1 protein associates with cellular receptors that contribute to neutrophil function in arthritis, and regulates C5a and LTB4 receptor-mediated activation and early neutrophil recruitment to the joints. Neutrophil-specific transcriptomics show that ELMO1 modulates neutrophil-specific gene expression that includes genes with known linkages to human arthritis. Finally, neutrophils from the peripheral blood of human donors that carry the SNP in ELMO1 associated with arthritis display increased migratory capacity, whereas ELMO1 knockdown reduces human neutrophil migration to LTB4. These data identify key 'non-canonical' roles for engulfment machinery components in arthritis, and ELMO1 as an important regulator of specific neutrophil receptors and signaling linked to arthritis. Overall design: The experiment consisted of two conditions: purified Ly6G+ bone marrow cells or peritoneal macrophages cultured overnight. Each condition consisted of four biological replicates.
A noncanonical role for the engulfment gene ELMO1 in neutrophils that promotes inflammatory arthritis.
Specimen part, Subject
View SamplesPluripotency is the differentiation capacity of particular cells exhibited in the early embryo in vivo and embryonic stem (ES) cells have been shown to originate from the inner cell mass (ICM) of an E3.5 blastocyst. Although the potential for ES cells to differentiate into the three germ layers is equated to ICM cells, they differ in the ability to maintain the capacity for self-renewal. Despite several studies on the maintenance of ES cells in the ground state of pluripotency, the precise mechanism of conversion from the ICM to the ES cell remains unclear. Here , we have examined the cell characteristics and expression profile within the intermediate stages of ES cell derivation from the ICM. Gene clustering and ontology (GO) analyses showed a significant change in the expression of epigenetic modifiers and DNA methylation-related genes in the intermediate stages. We have proposed that an epithelial-to-mesenchymal transition (EMT) blockage is required during derivation of mouse ES cells from E3.5 blastocysts. This study suggests a novel mechanistic insight into ES cell derivation and provides a time-course transcriptome profiling resource for the dissection of gene regulatory networks that underlie the transition from ICM to ES cells.
Blockage of the Epithelial-to-Mesenchymal Transition Is Required for Embryonic Stem Cell Derivation.
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Epigenetic Networks Regulate the Transcriptional Program in Memory and Terminally Differentiated CD8+ T Cells.
Specimen part, Treatment
View SamplesA permantly active form of the oncogene Akt was expressed in the keratinocytes of the basal proliferative layer of the epidermis. Stem cells of the hair follicle expressing the cell surface marker CD34 were isolated. RNA form the CD34(+) and CD34(-) keratinocytes was extracted and and hybridized to Mouse Genome 430 2.0 Affymetrix arrays.
Akt signaling leads to stem cell activation and promotes tumor development in epidermis.
Specimen part
View SamplesEpigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Epigenetic Networks Regulate the Transcriptional Program in Memory and Terminally Differentiated CD8+ T Cells.
Specimen part
View SamplesEpigenetic mechanisms play a critical role during differentiation of T cells by contributing to the formation of stable and heritable transcriptional patterns. To further study the mechanisms of memory maintenance in CD8+ T cells, we performed genome-wide analysis of DNA methylation, histone marking (H3K9Ac and H3K9me3) and gene expression profiles in naive, effector memory (EM) and terminally differentiated memory (TEMRA) cells. Our results indicate that DNA demethylation and histone acetylation are coordinated to generate the transcriptional program associated with memory cells. Conversely, EM and TEMRA cells share a very similar epigenetic landscape. Nonetheless, the TEMRA transcriptional program predicts an innate immunity phenotype associated with genes never reported in these cells, including several mediators of NK cell activation (VAV3 and LYN) and a large array of NK receptors (KIR2DL3, KIR2DL4, KIR2DL1, KIR3DL1, KIR2DS5, etc.). In addition, we identified up to 161 genes that encode transcriptional regulators, some of unknown function in CD8+ T cells, that were differentially expressed in the course of differentiation. Overall, these results provide new insights into the regulatory networks involved in memory CD8+ T cell maintenance and T cell terminal differentiation.
Epigenetic Networks Regulate the Transcriptional Program in Memory and Terminally Differentiated CD8+ T Cells.
Specimen part, Treatment
View SamplesWe identified the ubiquitin ligase Huwe1 as a crucial regulator of hematopoietic stem cell (HSC) functions. We generated Huwe1 conditional knock-out mice and discovered that the loss of this ligase causes an increased proliferation and stem cell exhaustion, together with a decreased lymphoid specification in vivo. We observed that the ubiquitin ligase Huwe1 is controlling the expression of N-myc at the level of the most immature stem and progenitor hematopoietic populations, mediating the described effects. Overall design: High-troughput RNA-sequencing of sorted HSC (Lin-Sca+Kit+CD48-CD150+) from wild type or Huwe1 conditional knockout mice (constitutively deleted with Vav-Cre recombinase or inducibly deleted with Mx1-Cre)
The ubiquitin ligase Huwe1 regulates the maintenance and lymphoid commitment of hematopoietic stem cells.
Specimen part, Subject
View SamplesWe identified the ubiquitin ligase Huwe1 as a crucial regulator of hematopoietic stem cell (HSC) functions. We generated Huwe1 conditional knock-out mice and discovered that the loss of this ligase causes an increased proliferation and stem cell exhaustion, together with a decreased lymphoid specification in vivo. We observed that the ubiquitin ligase Huwe1 is controlling the expression of N-myc at the level of the most immature stem and progenitor hematopoietic populations, mediating the described effects.
The ubiquitin ligase Huwe1 regulates the maintenance and lymphoid commitment of hematopoietic stem cells.
Specimen part
View SamplesIn the current study, we have performed a gene expression analysis of well characterized and defined populations of human adipose-derived stem cells (hASCs) before and after in vitro induction of osteogenic and myogenic differentiation that allows identifying DNA methylation- regulated differentiation genes. We have also address the extent of the epigenetic programming of hASCs- derived differentiated cells by comparing the expression profiling of these cells with their somatic counterparts from primary tissues. Finally, we also compared the patterns of expression of hASCs (and their derivatives)
DNA methylation plasticity of human adipose-derived stem cells in lineage commitment.
Specimen part
View SamplesBovine leukemia virus (BLV) Tax is a transcriptional activator of viral replication and a key contributor to oncogenic potential. We previously identified interesting mutant forms of Tax with elevated (TaxD247G) or reduced (TaxS240P) transactivation effects on BLV replication and propagation. In this study, to identify genes that play a role in the cascade of signal events regulated by wild-type and mutant Tax proteins, we used a large-scale host cell gene-profiling approach.
Identification of bovine leukemia virus tax function associated with host cell transcription, signaling, stress response and immune response pathway by microarray-based gene expression analysis.
Cell line
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