Mast cells, activated by antigen via the high affinity receptor for IgE (FcRI), release an array of pro-inflammatory mediators that contribute to allergic disorders such as asthma and anaphylaxis. The KIT ligand, stem cell factor (SCF), is critical for mast cell expansion, differentiation and survival, and, under acute conditions, enhances mast cell activation. However, extended SCF exposure in vivo conversely protects against fatal antigen-mediated anaphylaxis. In investigating this dichotomy, we identified a novel mode of regulation of the mast cell activation phenotype through SCF-mediated programming. We found that mouse bone marrow-derived mast cells chronically exposed to SCF displayed a marked attenuation of FcRI-mediated degranulation and cytokine production. The hypo-responsive phenotype was not a consequence of altered signals regulating calcium flux or protein kinase C, but of ineffective cytoskeletal reorganization, with evidence implicating a down-regulation of expression of the Src kinase Hck. Collectively, these findings demonstrate a major role for SCF in the homeostatic control of mast cell activation with potential relevance to mast cell-driven disease and the development of novel approaches for the treatment of allergic disorders.
Stem cell factor programs the mast cell activation phenotype.
Specimen part, Treatment
View SamplesBacillus anthracis is a gram-positive, aerobic, spore-forming, rod-shaped bacterium which has recently been used as an agent of bioterrorism. Because there is a significant delay between the initial contact of the spore with the host and clinical evidence of disease, there appears to be temporary containment of the pathogen by the innate immune system. Contact with the human alveolar macrophage (HAM) plays a key role in the innate immune response to B. anthracis spores. Therefore, the early macrophage response to anthrax exposure is important in understanding the pathogenesis of this disease. The majority of genes modulated by spores were upregulated, and a lesser number were downregulated. The data was subjected to Ingenuity Pathway analysis, the Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis, and the Promoter Analysis and Interaction Network Toolset (PAINT). Among the upregulated genes, we identified a group of chemokine ligands, apoptosis genes and, interestingly, keratin filament genes. Central hubs regulating the activated genes were TNF-alpha, NF-B and their ligands/receptors. Other activated genes included IL-1alpha and IL-18. RNA for these, and several additional cytokines including IL-6, IL-1gamma, IP-10 and GM-CSF, were differentially expressed from 1.6- to 27-fold. The microarray cytokine data is consistent with our previously published findings which demonstrated that there was 4- to 43-fold induction of these cytokines at the transcriptional and translational levels as determined by RNase protection assays and ELISA. The PAINT analysis revealed that the majority of the genes affected by spores contain the binding site for c-Rel, a member of the NF-B family of transcription factors. Other transcription regulatory elements contained in many of the upregulated genes were c-Myb, CP2, Barbie Box, E2F and CRE-BP1. This study is the first detailed microarray analysis to describe the HAM response to B. anthracis.
Gene expression profiling of human alveolar macrophages infected by B. anthracis spores demonstrates TNF-alpha and NF-kappab are key components of the innate immune response to the pathogen.
No sample metadata fields
View SamplesThe Hematopoietically-expressed homeobox transcription factor (Hhex) is important for the maturation of definitive hematopoietic progenitors and B-cells during development. We have recently shown that in adult hematopoiesis, Hhex is dispensable for maintenance of hematopoietic stem cells (HSCs) and myeloid lineages but essential for the commitment of Common Lymphoid Progenitors (CLPs) to lymphoid lineages. However, whether Hhex plays a role in HSC self-renewal and myeloid expansion during hematopoietic stress is unknown. Here we show that during serial bone marrow transplantation, Hhex-deleted HSCs are progressively lost, revealing an intrinsic defect in HSC self-renewal. Moreover, Hhex-deleted mice show markedly impaired hematopoietic recovery following myeloablation. In vitro, Hhex-null blast colonies were incapable of replating, implying a specific requirement for Hhex in immature hematopoietic progenitors. Transcriptome analysis of Hhex-null Lin-Sca+Kit+ (LSK) cells showed that Hhex deletion leads to the deregulation of Polycomb Repressive Complex 2 (PRC2) target genes, including an upregulation of Cdkn2a locus, encoding the cell cycle repressors p16Ink4a and p19Arf. Indeed, loss of Cdkn2a restored Hhex-null blast colony replating in vitro, as well as hematopoietic reconstitution following myeloablation in vivo. Thus, HSCs require Hhex to repress Cdkn2a to enable continued self-renewal and response to hematopoietic stress. Overall design: Transcriptional profiling of Hhex-deleted and wild-type LSK cells using RNA sequencing
Hhex Regulates Hematopoietic Stem Cell Self-Renewal and Stress Hematopoiesis via Repression of Cdkn2a.
Specimen part, Cell line, Subject
View SamplesInterleukin-33 (IL-33) is elevated in afflicted tissues of patients with mast cell-dependent chronic allergic diseases. Based on its acute effects on mouse mast cells (MCs), IL-33 is thought to play a role in the pathogenesis of allergic disease through MC activation. However, the manifestations of chronic IL-33 exposure on human MC function, which best reflect the conditions associated with chronic allergic disease, are unknown. We now find that long-term exposure of human and mouse MCs to IL-33 results in a substantial reduction of MC activation in response to antigen. This reduction required >72 h exposure to IL-33 for onset and 1-2 wk for reversion following IL-33 removal. This hypo-responsive phenotype was determined to be a consequence of MyD88-dependent attenuation of signaling processes necessary for MC activation including antigen-mediated calcium mobilization and cytoskeletal reorganization; potentially as a consequence of down-regulation of the expression of PLCg1 and Hck. These findings suggest that IL-33 may play a protective, rather than a causative role in MC activation under chronic conditions and, furthermore, reveal regulated plasticity in the MC activation phenotype. The ability to down-regulate MC activation in this manner may provide alternative approaches for treatment of MC-driven disease.
IL-33 induces a hyporesponsive phenotype in human and mouse mast cells.
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Human Monocyte Subsets Are Transcriptionally and Functionally Altered in Aging in Response to Pattern Recognition Receptor Agonists.
Specimen part, Disease, Treatment, Subject
View SamplesAge-related alterations in immunity have been linked to increased incidence of infections and decreased responses to vaccines in the aging population. Human peripheral blood monocytes are known to promote antigen presentation and antiviral activities; however, the impact of aging on monocyte functions remains an open question. We present an in-depth global analysis examining the impact of aging on classical (CD14+CD16-), intermediate (CD14+CD16+), and non-classical (CD14dimCD16+) monocytes. Monocytes sorted from non-frail healthy adults (18-40 yrs) and OLD ( 65 yrs) individuals were analyzed after stimulation with TLR4, TLR7/8, and RIG-I agonists. Our data showed under non-stimulated conditions, monocyte subsets did not reveal significant age-related alternations; however, agonist stimulated-monocytes from adults and OLD subjects did show differences at the transcriptional and functional levels. These alternations in many immune-related transcripts and biological processes resulted in reduced production of IFN, IFN, IL-1, CCL20, and CCL8, and higher expression of CX3CR1 in monocytes from OLD subjects. Our findings represent a comprehensive analysis of the influence of human aging on pattern recognition receptors signaling and monocyte functions, and have implications for strategies to enhance the immune response in the context of infection and immunization.
Human Monocyte Subsets Are Transcriptionally and Functionally Altered in Aging in Response to Pattern Recognition Receptor Agonists.
Specimen part, Disease, Treatment, Subject
View SamplesAge-related alterations in immunity have been linked to increased incidence of infections and decreased responses to vaccines in the aging population. Human peripheral blood monocytes are known to promote antigen presentation and antiviral activities; however, the impact of aging on monocyte functions remains an open question. We present an in-depth global analysis examining the impact of aging on classical (CD14+CD16-), intermediate (CD14+CD16+), and non-classical (CD14dimCD16+) monocytes. Monocytes sorted from non-frail healthy adults (18-40 yrs) and old ( 65 yrs) individuals were analyzed after stimulation with TLR4, TLR7/8, and RIG-I agonists. Our data showed under non-stimulated conditions, monocyte subsets did not reveal significant age-related alternations; however, agonist stimulated-monocytes from adults and old subjects did show differences at the transcriptional and functional levels. These alternations in many immune-related transcripts and biological processes resulted in reduced production of IFN, IFN, IL-1, CCL20, and CCL8, and higher expression of CX3CR1 in monocytes from old subjects. Our findings represent a comprehensive analysis of the influence of human aging on pattern recognition receptors signaling and monocyte functions, and have implications for strategies to enhance the immune response in the context of infection and immunization.
Human Monocyte Subsets Are Transcriptionally and Functionally Altered in Aging in Response to Pattern Recognition Receptor Agonists.
Subject
View SamplesThe respiratory system is a complex network of many cell types, including subsets of macrophages and dendritic cels, that work together to maintain steady-state respiration. Due to limitations in acquiring cells from healthy human lung, these subsets remain poorly characterized transcriptionally and phenotypically. We set out to systemically identify these subsets in human airways, by developing a schema of isolating large numbers of cells by whole lung bronchoalveolar lavage. Six subsets of phagocytic antigen presenting cells were consistently observed, which varied in their ability to internalize bacterial particles. Subsets could be further separated by their inherent capacities to upregulate CD83, CD86, and CCR7. Whole genome transcriptional profiling revealed a clade of true dendritic cells distinct from a macrophage/monocyte clade. Each clade, and each member of both clades, could be discerned by specific genes of increased expression, which would serve as markers for future studies in healthy and diseased states.
Transcriptional Classification and Functional Characterization of Human Airway Macrophage and Dendritic Cell Subsets.
Sex, Age
View SamplesLongitudinal analysis of monocyte gene expressions patterns before and after cessation of HAART: understanding the impact of HIV viremia on the monocyte tranascritome. We used microarrays to detail the global program of gene expression underlying defects in monocytes from HIV infected patients during viremia..
Diminished production of monocyte proinflammatory cytokines during human immunodeficiency virus viremia is mediated by type I interferons.
No sample metadata fields
View SamplesHypoxia signature in Clear cell RCC
Regulation of endocytosis via the oxygen-sensing pathway.
Specimen part, Disease, Disease stage
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