Although glucocorticoids (GCs) are known to exert numerous effects in the hippocampus, their chronic regulatory functions remain poorly understood. Moreover, evidence is inconsistent regarding the longstanding hypothesis that chronic GC exposure promotes brain aging/Alzheimer's disease. Here, we adrenalectomized male F344 rats at 15-months-of-age, maintained them for 3 months with implanted corticosterone (CORT) pellets producing low or intermediate (glucocorticoid-receptor (GR)-activating) blood levels of CORT, and performed microarray/pathway analyses in hippocampal CA1. We defined the chronic GC-dependent transcriptome as 393 genes that exhibited differential expression between Intermediate- and Low-CORT groups. Short-term CORT (4 days) did not recapitulate this transcriptome. Functional processes/pathways overrepresented by chronic CORT-upregulated genes included learning/plasticity, differentiation, glucose metabolism and cholesterol biosynthesis, whereas processes overrepresented by CORT-downregulated genes included inflammatory/immune/glial responses and extracellular structure. These profiles indicate that GCs chronically activate neuronal/metabolic processes while coordinately repressing a glial axis of reactivity/inflammation. We then compared the GC-transcriptome with a previously-defined hippocampal aging transcriptome, revealing a high proportion of common genes. Although CORT and aging moved expression of some common genes in the same-direction, the majority were shifted in opposite directions by CORT and aging (e.g., glial inflammatory genes downregulated by CORT are upregulated with aging). These results contradict the hypothesis that GCs simply promote brain aging, and also suggest that the opposite-direction shifts during aging reflect resistance to CORT regulation. Therefore, we propose a new model in which aging-related GC resistance develops in some target pathways while GC overstimulation develops in others, together generating much of the brain aging phenotype.
Glucocorticoid-dependent hippocampal transcriptome in male rats: pathway-specific alterations with aging.
Sex, Age, Specimen part
View SamplesPP2A regulates inflammatory cytokine/chemokine gene expression by dephosphorylating protein kinases at multiple signaling pathways from stimulated cells. In this dataset, Affymetrix mouse Gene ST 2.1 Array was used to assay total RNA extracted from LPS-treated PP2AC knockout BMDM (PP2ACfl/fl;lyM-Cre) and the control BMDM (PP2ACfl/fl)
Myeloid-Specific Gene Deletion of Protein Phosphatase 2A Magnifies MyD88- and TRIF-Dependent Inflammation following Endotoxin Challenge.
Specimen part
View SamplesCD8 T cells normally differentiate from resting nave T cells into function effector and then memory CD8 T cells following acute infections. During chronic viral infections, however, virus-specific CD8 T cells often become exhausted. We used microarrays to examine the gene expression differences between naive, effector, memory and exhausted virus-specific CD8 T cells following lymphocytic choriomeningitis virus infection.
Molecular signature of CD8+ T cell exhaustion during chronic viral infection.
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View SamplesThis study characterizes the response of primary human endothelial cells (human umbilical vein endothelial cells, HUVECs) to the relative shear stress changes that occur during the initiation of arteriogenesis at the entrance regions to a collateral artery network. HUVECs were preconditioned to a baseline level of unidirectional shear of 15 dynes/cm2 for 24 hours. After 24 hours preconditioning, HUVECs were subjected to an arteriogenic stimulus that mimics the shear stress changes observed in the opposing entrance regions into a collateral artery network. The arteriogenic stimulus consisted of a 100% step wise increase in shear stress magnitude to a unidirectional 30 dynes/cm2 in either the same or opposite direction of the preconditioned shear stress. This simulates either the feeding entrance to the collateral artery circuit or the region that drains into the vasculature downstream of an obstruction in a major artery, respectively. In vivo analysis of collateral growth in the mouse hindlimb showed enhanced outward remodeling in the re-entrant (direction reversing) region that reconnects to the downstream arterial tree, suggesting reversal of shear stress direction as a key enhancer of arteriogenesis. Transcriptional profiling using microarray techniques identified that the reversal of shear stress direction, but not an increase in shear stress alone, yielded a broad-based enhancement of the mechanotransduction pathways necessary for the induction of arteriogenesis.
Mechanisms of Amplified Arteriogenesis in Collateral Artery Segments Exposed to Reversed Flow Direction.
Specimen part
View SamplesAndrogenetic alopecia (AGA) or common baldness results from a marked decrease in hair follicle size. This miniaturization may be related to loss of hair follicle stem or progenitor cells. To test this hypothesis, we analyzed bald and non-bald scalp from the same individuals for the presence of hair follicle stem and progenitor cells using flow cytometry to quantitate cells expressing CYTOKERATIN 15 (KRT15), CD200, CD34 and ALPHA-6-INTEGRIN (ITGA6). High levels of KRT15 expression correlated with stem cell properties of small cell size and quiescence. Cells with the highest level of KRT15 expression were maintained in bald scalp; however, distinct populations of CD200high ITGA6high cells and CD34-positive cells were markedly diminished. Consistent with a progenitor cell phenotype, the diminished populations localized closely to the stem-cell rich bulge area but were larger and more proliferative than the bulge stem cells. In functional assays, analogous CD200 high /Itga6 high cells from murine hair follicles were multipotent and generated new hair follicles in skin reconstitution assays. These findings suggest that a defect in stem cell activation plays a role in the pathogenesis of AGA.
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Sex, Age, Specimen part
View SamplesMouse back skin was disassociated to single cells, sorted by cell surface markers and tested by microarrray
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Sex, Age, Specimen part
View SamplesHuman hair follicles from normal areas of the scalp were disassociated to single cells, sorted and tested by microarrray
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells.
Sex, Specimen part
View SamplesThe JAK2 mutation V617F is detectable in a majority of patients with Ph-negative myeloproliferative neoplasms (MPN). Enforced expression of JAK2 V617F in mice induces myeloproliferation and bone marrow (BM) fibrosis suggesting a causal role for the JAK2 mutant in the pathogenesis of MPN. However, little is known about mechanisms and effector molecules contributing to JAK2 V617F-induced myeloproliferation and fibrosis. Here we show that JAK2 V617F promotes expression of oncostatin M (OSM) in neoplastic myeloid cells. Correspondingly, OSM was found to be overexpressed in the BM and elevated in the serum of patients with JAK2 V617F+ MPN. In addition, OSM secreted by JAK2 V617F+ cells stimulated growth of fibroblasts and microvascular endothelial cells and induced the production of angiogenic and profibrogenic cytokines (HGF, VEGF, and SDF-1) in BM fibroblasts. All effects of MPN cell-derived OSM were blocked by a neutralizing anti-OSM antibody, whereas the production of OSM in MPN cells was effectively suppressed by a pharmacologic JAK2 inhibitor or RNAi-mediated knockdown of JAK2. In summary, JAK2 V617F-mediated upregulation of OSM may contribute to fibrosis, neoangiogenesis, and the cytokine storm observed in JAK2 V617F+ MPN, suggesting that OSM could serve as a novel therapeutic target molecule in these neoplasms.
Identification of oncostatin M as a JAK2 V617F-dependent amplifier of cytokine production and bone marrow remodeling in myeloproliferative neoplasms.
Cell line, Treatment
View SamplesBackground: Mycobacterium tuberculosis infection is a leading cause of infectious death worldwide. Gene-expression microarray studies profiling the blood transcriptional response of tuberculosis (TB) patients have been undertaken in order to better understand the host immune response as well as to identify potential biomarkers of disease. To date most of these studies have focused on pulmonary TB patients with gene-expression profiles of extra-pulmonary TB patients yet to be compared to those of patients with pulmonary TB or sarcoidosis.
The Transcriptional Signature of Active Tuberculosis Reflects Symptom Status in Extra-Pulmonary and Pulmonary Tuberculosis.
Sex, Age, Specimen part, Disease, Disease stage, Race
View SamplesMononuclear phagocytes are a diverse cell family that occupy all tissues and assume numerous functions to support tissue and systemic homeostasis. Our ability to investigate the roles of individual subsets is limited by an absence of approaches to ablate gene function within specific sub-populations. Using Nr4a1-dependent Ly6Clow monocytes as a representative cell type we show that enhancer deletion addresses these limitations. Combining ChIP-Seq and molecular approaches we identify a single, conserved, sub-domain within the Nr4a1 enhancer that is essential for Ly6Clow monocyte development. Mice lacking this enhancer lack Ly6Clow monocytes but retain Nr4a1 gene expression in macrophages during steady state and in response to LPS. Nr4a1 is a key negative regulator of inflammatory gene expression and decoupling these processes allows Ly6Clow monocytes to be studied without confounding influences. Enhancer targeting possesses greater specificity than cre recombinase-mediated gene deletion, providing a route to generate loss-of-function models in closely related cell types. Overall design: Paired End mRNA sequencing of FACS purified primary murine MDP, cMoP, Ly6Chi and Ly6Clow monocytes from the bone marrow and Ly6Chi and Ly6Clow monocytes from the peripheral blood
Deleting an Nr4a1 Super-Enhancer Subdomain Ablates Ly6C<sup>low</sup> Monocytes while Preserving Macrophage Gene Function.
Specimen part, Cell line, Subject
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