Project description:Uterine Mast cells (MCs) are essential for placentation, implantation and growth of fetus. In contrast, the functions of placental MCs are poorly investigated. The objective of the study was to evaluate the transcriptional profile of human placental MCs using whole genome microarray. We isolated MCs from placenta from healthy at term donors with CD117 and IgE antibodies, and used HMC-1.2 cell lines as controls. Data analysis revealed 16,468 genes modulated in human placenta MCs as compared with HMC-1.2 cell lines; most of them (83%) were up-regulated. The differentially expressed genes in placental MCs were enriched with three biological categories: immune response, FcReI signaling and reproduction processes. The two first categories revealed the importance of immune gene expression including chemokines, cytokines, interferon, and major histocompatibility complex antigens in placental MCs. A set of genes were modulated in FcReI process suggesting a role of IgE-mediated activation. Finally, in pregnancy category, we identified specific genes of WNT pathway and those involved in response to estrogen and progesterone. Taken together, human placental MCs exhibited a unique transcriptional profile enriched with immune response and pregnancy genes, which reflects the impact of placenta environment on MC functions.
Project description:Mast cells are hematopoietic cells that reside preferentially in tissues exposed to internal and external environments. Mast cells sense immunological, inflammatory and environmental stimuli, and can be activated to release granules and generate inflammatory mediators. Mast cell-derived products confer protection against snake venoms and some parasite infections. Aberrant activation of mast cells is a major contributor to human pathology, including allergy, asthma and adverse drug reactions. Their strict tissue location has largely impeded the isolation of large numbers of primary mast cell for further analysis. To better understand the biology of mast cells, we analyzed the proteome of primary human and mouse mast cells by quantitative mass spectrometry. We identified a mast cell-specific protein signature that was conserved from mouse to man. Compared to a comprehensive set of other immune cell lineages, proteome analysis identified a unique and distant mast cell cluster. The mast cell signature included proteins governing granule biosynthesis and secretion, as well as proteoglycan- and neurotransmitter metabolism. Proteome conservation across species suggests evolutionary maintenance of mast cell functions.
Project description:Mast cells are known to be the key players in type I hypersensitivity reactions in humans and mice. They are critically involved in the development of allergic rhinitis, allergic asthma and systemic anaphylaxis. In this study we investigated the role of the transcriptional regulator MAZR in mast cells by comparing the expression profile of mast cells generated from wild-type (MazrF/F) and MAZR-deficient (MazrF/F x Vav-iCre) bone marrow cells. Our results from the array data demonstrate that MAZR acts preferentially as a transcriptional repressor in mast cells.
Project description:Mast cells and basophils are developmentally related cells whose activation is a hallmark of allergy. Functionally, mast cells and basophils overlap in their ability to produce several mediators, including histamine and granule proteases, but studies have increasingly demonstrated non-redundant roles. To characterize the transcriptional heterogeneity of mast cells and basophils upon their activation, we performed large-scale comparative microarrays of murine bone marrow–derived mast cells (BMMCs) and basophils (BMBs) at rest, upon an adaptive-type activation (IgE crosslinking), or upon an innate-type activation (IL-33 stimulation). Hierarchical clustering demonstrated that BMMCs and BMBs shared specific activation-associated transcriptional signatures but differed in others, both between cell type and between activation mode. In BMMCs, IgE crosslinking upregulated 785 genes including Egr2, Ccl1, and Fxyd6, while IL-33 stimulation induced 823 genes including Ccl1, Egr2, and Il1b. Focused bioinformatics pathway analysis demonstrated that IgE activation aligned with processes such as oxidative phosphorylation, angiogenesis, and the p53 pathway. The IL-33–activated transcriptome was enriched in genes commonly altered by NF-B in response to TNF, by IL-6 via STAT3, and in response to IFN. Furthermore, BMBs activated via IgE crosslinking selectively induced immune response genes Ccl1, Il3, and Il2 compared to IL-33–stimulated BMBs. Principal-component analysis revealed key cell- and activation-specific clustering. Overall, our data demonstrate that mast cells and basophils have cell- and activation-specific transcriptional responses and suggest that context-specific gene networks and pathways may shape how the immune system responds to allergens and innate cytokines.
Project description:In patients with chronic pulmonary disease colonization with the mold Aspergillus fumigatus is associated with declining pulmonary function and obstructive airway disease. One potential effector of this inflammatory response is the pulmonary mast cell. In vitro studies have demonstrated that A. fumigatus contact induces IgE-independent mast cell degranulation. Conversely, the Aspergillus secondary metabolite gliotoxin has been shown to suppress mast cell activation. These contradictory results emphasize the need for a better understanding of the interactions between A. fumigatus and mast cells. Thus, the objective of this work was to identify A. fumigatus genes that are differentially regulated upon exposure to mast cells. Transcriptional profiling experiments indicated that, in addition to genes encoding for iron acquisition systems, allergens and putative virulence factors, genes from the gliotoxin biosynthesis cluster were significantly down-regulated upon exposure to mast cells. Globally, the results from this study provide insight into the A. fumigatus response to mast cells and suggest that one mechanism by which the host may circumvent the effects of gliotoxin is via the suppression of fungal gliotoxin synthesis by mast cells.
Project description:We performed large-scale comparative microarrays of bone marrow -derived mast cells and basophils at rest, upon an adaptive-type action (IgE-crosslinking) or upon innate-type activation (IL-33-activation).