Neutrophil homeostasis is maintained, in part, by the regulated release of neutrophils from the bone marrow. Constitutive expression of the chemokine CXCL12 by bone marrow stromal cells provides a key retention signal for neutrophils in the bone marrow through activation of its receptor CXCR4. Herein, we show that the ELR chemokines CXCL1 and CXCL2 are constitutively expressed by bone marrow endothelial cells and osteoblasts, and CXCL2 expression is induced in endothelial cells during granulocyte colony-stimulating factor (G-CSF)-induced neutrophil mobilization. Neutrophils lacking CXCR2, the receptor for CXCL1 and CXCL2, are preferentially retained in the bone marrow, reproducing a myelokathexis phenotype. Transient disruption of CXCR4 failed to mobilize CXCR2 neutrophils. However, doubly deficient neutrophils (CXCR2-/- CXCR4-/-) displayed constitutive mobilization, showing that CXCR4 plays a dominant role. Collectively, these data suggest that CXCR2 signaling is a second chemokine axis that interacts antagonistically with CXCR4 to regulate neutrophil release from the bone marrow.
CXCR2 and CXCR4 antagonistically regulate neutrophil trafficking from murine bone marrow.
Specimen part, Treatment
View SamplesMicroRNAs fine-tune the activity of hundreds of protein-coding genes. The identification of tissue-specific microRNAs and their promoters has been constrained by the limited sensitivity of prior microRNA quantification methods. Here we determine the entire microRNAome of three endoderm-derived tissues, liver, small intestine, and pancreas, using ultra-high throughput sequencing. Although many microRNA genes are expressed at comparable levels, 162 microRNAs exhibited striking tissue-specificity. After mapping the promoters for these microRNA genes using H3K4me3 histone occupancy, we analyzed the regulatory modules of 63 microRNAs differentially expressed between liver and small intestine or pancreas. We determined that the same transcriptional regulatory mechanisms govern tissue-specific gene expression of both mRNA and microRNA encoding genes in mammals.
Tissue-specific regulation of mouse microRNA genes in endoderm-derived tissues.
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View SamplesWe tamoxifen treated 8-12 week old mice that had floxed alleles of the following: 1) both Apc alleles (giving rise to Apc truncation/inactivation); 2) both Cdx2 alleles (giving rise to Cdx2 inactivation; 3) one Braf allele, that upon Cre-mediated recombination gives a Braf V600E mutant allele (details below), and 4) the combination of both the Cdx2 alleles and the BrafV600E allele. All four of those groups also had a CDX2P-CreERT2 transgene that expresses Cre recombinase fused to a tamoxifen-regulated fragment of the estrogen receptor ligand binding domain. CreERT2 expression occurs only in tissues where the Cdx2 gene is expressed, which is almost exclusively in adult mouse cecum and colon epithelium. A fifth group of mice had the floxed Cdx2 alleles, but no CDX2P-CreERT2 gene. Treating the mice having CDX2P-CreERT2 with tamoxifen permits the Cre recombinase to enter the cell nucleus and recombine the Apc, Braf, and/or Cdx2 alleles containing loxP sequence elements. Mice were treated with intraperitoneal injection of tamoxifen dissolved in corn oil. Three mice per group were used. The control mice did not develop tumors or any morphological or histological changes in their epithelium, but their colons were used to create the 3 control samples. To obtain the BrafV600E allele we used a genetically engineered mouse line previously described by Dankort et al. (Genes Dev 2007, 21:379-84) that can express the BrafV600E mutant protein following Cre-mediated recombination. The Braf(CA) (Braf-Cre-activated) allele mice carry a gene-targeted allele of Braf, where Braf sequences from exons 15-18 are present in the normal mouse Braf intron 14, followed by a mutated exon 15 (carrying the V600E mutation). The exon 15-18 sequence element is flanked by loxP sites. In the absence of Cre-mediated recombination, the Braf(CA) allele expresses a wild type Braf protein. Following Cre-mediated recombination, the Braf exon 15-18 element is removed, and the Braf(CA) allele then encodes the Braf V600E protein (from the introduced mutated exon 15). RNA was purified from tumor or normal tissue, and targets for Affymetrix arrays were synthesized from the mRNAs. We used Affymetrix Mouse Gene 2.1 ST arrays, which hold 41345 probe-sets, but we largely analyzed just those 25216 probe-sets that were mapped to Entrez gene IDs. Raw data was processed with the Robust Multi-array Average algorithm (RMA). Data is log2-transformed transcript abundance estimates. We fit a one-way ANOVA model to the five groups of samples. We supply a supplementary excel workbook that holds the same data as the data matrix file, but also holds the probe-set annotation at the time we analyzed the data, and some simple statistical calculations, which selects subsets of the probe-sets as differentially expressed between pairs of groups, as well as significant Cdx2-/- by Braf V600E interactions. It also gives the homologous human gene IDs we used for enrichment testing, which were 1-to-1 best homologs according to build 68 of NCBI's Homologene. A second supplementary sheet shows the data we enrichment tested after collapsing to distinct human homologs, joins of the results of tests with GSE4045 data and of tests with TCGA data to the mouse genes, and the intersections of selected genes in those data set with our gene selections in mouse. Consumers should consider obtaining more up-to-date probe-set annotation for the array platform.
BRAF<sup>V600E</sup> cooperates with CDX2 inactivation to promote serrated colorectal tumorigenesis.
Sex, Treatment
View SamplesHematopoietic stem cells (HSCs) primarily reside in the bone marrow where signals generated by stromal cells regulate their self-renewal, proliferation, and trafficking. Endosteal osteoblasts and perivascular stromal cells including endothelial cells3, CXCL12-abundant reticular (CAR) cells, leptin-receptor positive stromal cells, and nestin-GFP positive mesenchymal progenitors have all been implicated in HSC maintenance. However, it is unclear if specific hematopoietic progenitor cell (HPC) subsets reside in distinct niches defined by the surrounding stromal cells and the regulatory molecules they produce. CXCL12 (stromal-derived factor-1, SDF-1) regulates both HSCs and lymphoid progenitors and is expressed by all of these stromal cell populations.
CXCL12 in early mesenchymal progenitors is required for haematopoietic stem-cell maintenance.
Specimen part
View SamplesWe studied changes in a whole transcriptome during dsDNA virus infection. Overall design: Fibroblasts (MRC5 & HFF) and epithelial cells (ARPE19) were infected with HCMV, HSV1 or Ad5 and total RNA was isolated at 48, 9, or 24 hpi, respectively. Total 15 treatments were used. There were 2 biological replicates analyzed per each treatment.
A tumor-specific endogenous repetitive element is induced by herpesviruses.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
G-CSF regulates hematopoietic stem cell activity, in part, through activation of Toll-like receptor signaling.
Specimen part, Treatment
View SamplesRecent studies demonstrate that inflammatory signals regulate hematopoietic stem cells (HSCs). Granulocyte-colony stimulating factor (G-CSF) is often induced with infection and plays a key role in the stress granulopoiesis response. However, its effects on HSCs are less clear. Herein, we show that treatment with G-CSF induces expansion and increased quiescence of phenotypic HSCs, but causes a marked, cell-autonomous HSC repopulating defect associated with induction of toll-like receptor (TLR) expression and signaling. The G-CSF-mediated expansion of HSCs is reduced in mice lacking TLR2, TLR4 or the TLR signaling adaptor MyD88. Induction of HSC quiescence is abrogated in mice lacking MyD88 or in mice treated with antibiotics to suppress intestinal flora. Finally, loss of TLR4 or germ free conditions mitigates the G-CSF-mediated HSC repopulating defect. These data suggest that low level TLR agonist production by commensal flora contributes to the regulation of HSC function and that G-CSF negatively regulates HSCs, in part, by enhancing TLR signaling.
G-CSF regulates hematopoietic stem cell activity, in part, through activation of Toll-like receptor signaling.
Specimen part, Treatment
View SamplesRecent studies demonstratethat inflammatory signals regulate hematopoietic stem cells (HSCs). Granulocyte-colony stimulating factor (G-CSF) is often induced with infection and plays a key role in the stress granulopoiesis response. However, its effects on HSCs are less clear. Herein, we show that treatment with G-CSF induces expansion and increased quiescence of phenotypic HSCs, but causes a marked, cell-autonomous HSC repopulating defect associated with induction of toll-like receptor (TLR) expression and signaling. The G-CSF-mediated expansion of HSCs is reduced in mice lacking TLR2, TLR4 or the TLR signaling adaptor MyD88. Induction of HSC quiescence is abrogated in mice lacking MyD88 or in mice treated with antibiotics to suppress intestinal flora. Finally, loss of TLR4 or germ free conditions mitigates the G-CSF-mediated HSC repopulating defect. These data suggest that low level TLR agonist production by commensal flora contributes to the regulation of HSC function and that G-CSF negatively regulates HSCs, in part, by enhancing TLR signaling.
G-CSF regulates hematopoietic stem cell activity, in part, through activation of Toll-like receptor signaling.
Specimen part, Treatment
View SamplesWe studied changes in a whole transcriptome during HCMV infection. Overall design: Fibroblasts (MRC5) were infected with HCMV and total RNA was isolated at 48. Total 2 individual samples were used. There were 3 replicates analyzed per individual sample.
A tumor-specific endogenous repetitive element is induced by herpesviruses.
Specimen part, Subject
View SamplesImmune cell infiltration in myositis were by examining microarray expression profiles in muscle biopsies from 31 myositis patients and 5 normal controls.
Genomic signatures characterize leukocyte infiltration in myositis muscles.
Sex, Specimen part, Disease, Disease stage
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