scholarly journals Phagocytic Cell Killing Mediated by Secreted Cytotoxic Factors of Vibrio cholerae

2000 ◽  
Vol 68 (9) ◽  
pp. 4930-4937 ◽  
Author(s):  
Vasu Punj ◽  
Olga Zaborina ◽  
Neelam Dhiman ◽  
Kim Falzari ◽  
M. Bagdasarian ◽  
...  
Keyword(s):  
Cell Death ◽  
Mast Cell ◽  
Mast Cells ◽  
Vibrio Cholerae ◽  
Growth Medium ◽  
Adenylate Kinase ◽  
Morphological Changes ◽  
Nucleoside Diphosphate Kinase ◽  
Phagocytic Cell ◽  
Nuclear Fragmentation

ABSTRACT Vibrio cholerae strain VB1 secretes a number of enzymes into the outside medium that utilize ATP as a substrate. Such enzymes are found in the outside medium during the mid-log phase of growth, when the optical density at 650 nm is about 0.4, and they demonstrate nucleoside diphosphate kinase (Ndk), 5′ nucleotidase, and adenylate kinase (Ak) activities. We report that the filtered growth medium ofV. cholerae, as well as the flowthrough fraction of a green Sepharose column during fractionation of the growth medium, had very little cytotoxicity by itself towards macrophages and mast cells but exhibited significant cytotoxicity in the presence of exogenous ATP. Such fractions, harboring 5′ nucleotidase, Ndk, and presumably other ATP-utilizing enzymes, demonstrated enhanced macrophage and mast cell death; periodate-oxidized-ATP (oATP)-treated macrophage and mast cells or such cells exposed to 0.1 mM Mg2+, where surface-associated P2Z receptors could not be activated, were not susceptible to subsequent ATP addition. Microscopic visualization of mast cells clearly demonstrated cell morphological changes such as swelling, vacuolization, and nuclear fragmentation following treatment with ATP and the growth medium of V. cholerae; however, these effects were suppressed if the mast cells were pretreated with oATP. These results strongly imply that the secreted ATP-utilizing enzymes of V. cholerae modulate the external ATP levels of the macrophage and mast cells, leading to their accelerated death, presumably through activation of P2Z receptors. Thus, development of inhibitors for such enzymes may reduce the level of V. cholerae infection; alternatively, mutations in such genes may eliminate V. cholerae survival in the gut and contribute to a safer live vaccine.

scholarly journals Indirect involvement of allergen-captured mast cells in antigen presentation

Blood ◽  
2008 ◽  
Vol 111 (3) ◽  
pp. 1489-1496 ◽  
Author(s):  
Taku Kambayashi ◽  
Jan D. Baranski ◽  
Rebecca G. Baker ◽  
Tao Zou ◽  
Eric J. Allenspach ◽  
...  
Keyword(s):  
Cell Death ◽  
Mast Cell ◽  
T Cell ◽  
Mast Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immunoglobulin E ◽  
Complex Class ◽  
Cell Responses ◽  
Histocompatibility Complex

Abstract It is generally thought that mast cells influence T-cell activation nonspecifically through the release of inflammatory mediators. In this report, we provide evidence that mast cells may also affect antigen-specific T-cell responses by internalizing immunoglobulin E–bound antigens for presentation to antigen-specific T cells. Surprisingly, T-cell activation did not require that mast cells express major histocompatibility complex class II, indicating that mast cells were not involved in the direct presentation of the internalized antigens. Rather, the antigen captured by mast cells is presented by other major histocompatibility complex class II+ antigen-presenting cells. To explore how this may occur, we investigated the fate of mast cells stimulated by antigen and found that FcϵRI crosslinking enhances mast cell apoptosis. Cell death by antigen-captured mast cells was required for efficient presentation because protection of mast cell death significantly decreased T-cell activation. These results suggest that mast cells may be involved in antigen presentation by acting as an antigen reservoir after antigen capture through specific immunoglobulin E molecules bound to their FcϵRI. This mechanism may contribute to how mast cells impact the development of T-cell responses.

Histone Deacetylase Inhibitor SAHA Mediates Epigenetic Silencing of KIT D816V Mutated Systemic Mastocytosis Primary Mast Cells and Selective Apoptosis of Mutated Mast Cells

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2834-2834 ◽  
Author(s):  
Hani Abdulkadir ◽  
Jennine Grootens ◽  
Matilda Kjellander ◽  
Eva Hellstrom Lindberg ◽  
Gunnar Nilsson ◽  
...  
Keyword(s):  
Cell Death ◽  
Mast Cell ◽  
Mast Cells ◽  
Histone Deacetylase ◽  
Histone Deacetylase Inhibitors ◽  
Conflicts Of Interest ◽  
Systemic Mastocytosis ◽  
Specific Treatment ◽  
Epigenetic Silencing ◽  
Kit Receptor

Abstract Systemic mastocytosis (SM) is a myeloproliferative disease for which there is currently no specific therapy. Over 90% of the patients carry the D816V point mutation that renders the KIT receptor constitutively active. In the current study, we assessed the sensitivity of mast cell line HMC1.2 and primary SM patient mast cells to histone deacetylase inhibitors, and found that SAHA is most efficient. SAHA induced a rapid downregulation of KIT mRNA, with a subsequent reduction in total KIT protein as well as cell surface KIT. This was followed by major mast cell apoptosis. Primary SM patient mast cells cultured ex vivo were even more sensitive to SAHA than HMC1.2 cells, whereas healthy subject mast cells were unaffected. There was a correlation between cell death and SM disease severity, where cell death was more pronounced in the case of aggressive disease, with almost 100% cell death among mast cells from the mast cell leukemia patient. Using ChIP qPCR, we found that the level of active chromatin mark H3K18ac/totalH3 decreased significantly in the KIT region, due to an increase in H3 density. This epigenetic silencing was specific to the KIT region and not seen in control genes upstream and downstream of KIT. Primary analysis of ChIP-seq data for histone marks H3K4me3 and H3K27me3, demonstrates a downregulation of transcription factors involved in activation of KIT receptor, such as MAPK, for the SAHA treated samples. This indicates an indirect epigenetic silencing of KIT. Our results therefore demonstrate that SAHA epigenetically silences KIT, and work is ongoing to elucidate the exact mechanisms of KIT regulation. Altogether, SAHA maybe a specific treatment for SM. Disclosures No relevant conflicts of interest to declare.

Chronic peripheral administration of corticotropin-releasing factor causes colonic barrier dysfunction similar to psychological stress

2008 ◽  
Vol 295 (3) ◽  
pp. G452-G459 ◽  
Author(s):  
Aaron A. Teitelbaum ◽  
Mélanie G. Gareau ◽  
Jennifer Jury ◽  
Ping Chang Yang ◽  
Mary H. Perdue
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Horseradish Peroxidase ◽  
Psychological Stress ◽  
Morphological Changes ◽  
Short Circuit ◽  
Light And Electron Microscopy ◽  
Bacterial Attachment ◽  
Barrier Dysfunction ◽  
Ussing Chambers

Chronic psychological stress causes intestinal barrier dysfunction and impairs host defense mechanisms mediated by corticotrophin-releasing factor (CRF) and mast cells; however, the exact pathways involved are unclear. Here we investigated the effect of chronic CRF administration on colonic permeability and ion transport functions in rats and the role of mast cells in maintaining the abnormalities. CRF was delivered over 12 days via osmotic minipumps implanted subcutaneously in wild-type (+/+) and mast cell-deficient (Ws/Ws) rats. Colonic segments were excised for ex vivo functional studies in Ussing chambers [short-circuit current ( Isc), conductance ( G), and macromolecular permeability (horseradish peroxidase flux)], and analysis of morphological changes (mast cell numbers and bacterial host-interactions) was determined by light and electron microscopy. Chronic CRF treatment resulted in colonic mucosal dysfunction with increased Isc, G, and horseradish peroxidase flux in +/+ but not in Ws/Ws rats. Furthermore, CRF administration caused mast cell hyperplasia and abnormal bacterial attachment and/or penetration into the mucosa only in +/+ rats. Finally, selective CRF agonist/antagonist studies revealed that stimulation of CRF-R1 and CRF-R2 receptors induced the elevated secretory state and permeability dysfunction, respectively. Chronic CRF causes colonic barrier dysfunction in rats, which is mediated, at least in part, via mast cells. This information may be useful in designing novel treatment strategies for stress-related gastrointestinal disorders.

scholarly journals Nanoimaging granule dynamics and subcellular structures in activated mast cells using soft X-ray tomography

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Huan-Yuan Chen ◽  
Dapi Meng-Lin Chiang ◽  
Zi-Jing Lin ◽  
Chia-Chun Hsieh ◽  
Gung-Chian Yin ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Lipid Droplets ◽  
Plasma Membranes ◽  
Cell Activation ◽  
Morphological Changes ◽  
Three Dimensions ◽  
Mast Cell Activation ◽  
Giant Vesicles ◽  
X Ray

Abstract Mast cells play an important role in allergic responses. During activation, these cells undergo degranulation, a process by which various kinds of mediators stored in the granules are released. Granule homeostasis in mast cells has mainly been studied by electron microscopy (EM), where the fine structures of subcellular organelles are partially destroyed during sample preparation. Migration and fusion of granules have not been studied in detail in three dimensions (3D) in unmodified samples. Here, we utilized soft X-ray tomography (SXT) coupled with fluorescence microscopy to study the detailed structures of organelles during mast cell activation. We observed granule fission, granule fusion to plasma membranes, and small vesicles budding from granules. We also detected lipid droplets, which became larger and more numerous as mast cells were activated. We observed dramatic morphological changes of mitochondria in activated mast cells and 3D-reconstruction revealed the highly folded cristae inner membrane, features of functionally active mitochondria. We also observed giant vesicles containing granules, mitochondria, and lipid droplets, which we designated as granule-containing vesicles (GCVs) and verified their presence by EM in samples prepared by cryo-substitution, albeit with a less clear morphology. Thus, our studies using SXT provide significant insights into mast cell activation at the organelle level.

scholarly journals Tryptase Regulates the Epigenetic Modification of Core Histones in Mast Cell Leukemia Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Sultan Alanazi ◽  
Fabio Rabelo Melo ◽  
Gunnar Pejler
Keyword(s):  
Cell Death ◽  
Mast Cell ◽  
Mast Cells ◽  
Epigenetic Modification ◽  
Secretory Granules ◽  
Leukemia Cells ◽  
Human Mast Cell ◽  
Cell Leukemia ◽  
Core Histones ◽  
Mast Cell Leukemia

Mast cells are immune cells that store large amounts of mast cell-restricted proteases in their secretory granules, including tryptase, chymase and carboxypeptidase A3. In mouse mast cells, it has been shown that tryptase, in addition to its canonical location in secretory granules, can be found in the nuclear compartment where it can impact on core histones. Here we asked whether tryptase can execute core histone processing in human mast cell leukemia cells, and whether tryptase thereby can affect the epigenetic modification of core histones. Our findings reveal that triggering of cell death in HMC-1 mast cell leukemia cells is associated with extensive cleavage of core histone 3 (H3) and more restricted cleavage of H2B. Tryptase inhibition caused a complete blockade of such processing. Our data also show that HMC-1 cell death was associated with a major reduction of several epigenetic histone marks, including H3 lysine-4-mono-methylation (H3K4me1), H3K9me2, H3 serine-10-phosphorylation (H3S10p) and H2B lysine-16-acetylation (H2BK16ac), and that tryptase inhibition reverses the effect of cell death on these epigenetic marks. Further, we show that tryptase is present in the nucleus of both viable and dying mast cell leukemia cells. In line with a role for tryptase in regulating nuclear events, tryptase inhibition caused increased proliferation of the mast cell leukemia cells. Altogether, the present study emphasizes a novel principle for how epigenetic modification of core histones is regulated, and provides novel insight into the biological function of human mast cell tryptase.

scholarly journals Dynamics of Plasma and Granule Membrane in Murine Bone Marrow-Derived Mast Cells after Re-stimulation

2015 ◽  
Vol 8 (1) ◽  
pp. 14-22
Author(s):  
Masahiro Kaneko ◽  
Arisa Yamada
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Plasma Membrane ◽  
Mast Cells ◽  
Morphological Changes ◽  
Membrane Dynamics ◽  
Hematopoietic Stem ◽  
Murine Bone Marrow ◽  
Cell Functions ◽  
Granule Membrane

Mast cells are derived from hematopoietic stem cells and play important roles in allergic responses. Mast cells are long-lived compared with other granular cell types. Since the response of the individual mast cell after FcεRI-induced degranulation is unclear, the aim of this study was to analyze morphological changes in individual mast cells after restimulation. To observe plasma and granule membrane dynamics, AcGFP-actb (β-actin) and DsRed-monomer (DRM)- CD63 fusion constructs were introduced into bone marrow-derived mast cells (BMMCs). Furthermore, AcGFP-CD63 and DRM-Cma1 (mMCP-5) were introduced into BMMCs. Re-stimulation resulted in increased β-hexosaminidase release and cytokine mRNA expression similar to those observed during initial stimulation. Moreover, expression of FcεRI on BMMCs 24 h after initial stimulation was similar to that measured before initial stimulation. Changes in morphology of the plasma membrane and colocalization of granules and plasma membrane were observed after initial stimulation. BMMCs returned to normal 120 min after the initial stimulation. These phenomena were also observed in BMMCs after re-stimulation. BMMC chymase content decreased 20 min after stimulation but returned to near normal 24 h after stimulation. These findings suggest that mast cell functions can be maintained and that these cells can be repeatedly degranulated after FcεRI-mediated stimulation.

scholarly journals Granule Leakage Induces Cell-Intrinsic, Granzyme B-Mediated Apoptosis in Mast Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Sabrina Sofia Burgener ◽  
Melanie Brügger ◽  
Nathan Georges François Leborgne ◽  
Sophia Sollberger ◽  
Paola Basilico ◽  
...  
Keyword(s):  
Cell Death ◽  
Mast Cell ◽  
Mast Cells ◽  
Serine Protease ◽  
Caspase 3 ◽  
Granzyme B ◽  
Allergic Diseases ◽  
Mast Cell Activation ◽  
Dependent Manner ◽  
Cell Suicide

Mast cells are multifunctional immune cells scattered in tissues near blood vessels and mucosal surfaces where they mediate important reactions against parasites and contribute to the pathogenesis of allergic reactions. Serine proteases released from secretory granules upon mast cell activation contribute to these functions by modulating cytokine activity, platelet activation and proteolytic neutralization of toxins. The forced release of granule proteases into the cytosol of mast cells to induce cell suicide has recently been proposed as a therapeutic approach to reduce mast cell numbers in allergic diseases, but the molecular pathways involved in granule-mediated mast cell suicide are incompletely defined. To identify intrinsic granule proteases that can cause mast cell death, we used mice deficient in cytosolic serine protease inhibitors and their respective target proteases. We found that deficiency in Serpinb1a, Serpinb6a, and Serpinb9a or in their target proteases did not alter the kinetics of apoptosis induced by growth factor deprivation in vitro or the number of peritoneal mast cells in vivo. The serine protease cathepsin G induced marginal cell death upon mast cell granule permeabilization only when its inhibitors Serpinb1a or Serpinb6a were deleted. In contrast, the serine protease granzyme B was essential for driving apoptosis in mast cells. On granule permeabilization, granzyme B was required for caspase-3 processing and cell death. Moreover, cytosolic granzyme B inhibitor Serpinb9a prevented caspase-3 processing and mast cell death in a granzyme B-dependent manner. Together, our findings demonstrate that cytosolic serpins provide an inhibitory shield preventing granule protease-induced mast cell apoptosis, and that the granzyme B-Serpinb9a-caspase-3 axis is critical in mast cell survival and could be targeted in the context of allergic diseases.

Cytochemical analysis of mast cell granules after poly-dl-lysine action

1978 ◽  
Vol 36 (2) ◽  
pp. 278-279
Author(s):  
R. Courtoy ◽  
L.J. Simar ◽  
J. Christophe
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Chemical Compounds ◽  
Cellular Membrane ◽  
Thin Sections ◽  
Organic Bases ◽  
Ferric Thiocyanate ◽  
Cytochemical Analysis ◽  
Mast Cell Granule ◽  
Amine Liberation

Several chemical compounds induce amine liberation from mast cells but do not necessarily provoque the granule expulsion. For example, poly-dl-lysine induces modifications of the cellular membrane permeability which promotes ion exchange at the level of mast cell granules. Few of them are expulsed but the majority remains in the cytoplasm and appears less dense to the electrons. A cytochemical analysis has been performed to determine the composition of these granules after the polylysine action.We have previously reported that it was possible to demonstrate polyanions on epon thin sections using a cetylpyridinium ferric thiocyanate method. Organic bases are selectively stained with cobalt thiocyanate and the sulfhydryle groups are characterized with a silver methenamine reaction. These techniques permit to reveal the mast cell granule constituents, i.e. heparin, biogenic amines and basic proteins.

Magnesium and sulfur in mast cell and basophil granules of lower vertebrates in relation with histamine

1992 ◽  
Vol 50 (2) ◽  
pp. 1596-1597
Author(s):  
Kenichi Takaya
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Mast Cell ◽  
Mast Cells ◽  
Tree Frog ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Fresh Frozen ◽  
Ultrathin Sections

Mast cell and basophil granules of the vertebrate contain heparin or related sulfated proteoglycans. Histamine is also present in mammalian mast cells and basophils. However, no histamine is detected in mast cell granules of the amphibian or fish, while it is shown in those of reptiles and birds A quantitative x-ray microanalysis of mast cell granules of fresh frozen dried ultrathin sections of the tongue of Wistar rats and tree frogs disclosed high concentrations of sulfur in rat mast cell granules and those of sulfur and magnesium in the tree frog granules. Their concentrations in tree frog mast cell granules were closely correlated (r=0.94).Fresh frozen dried ultrathin sections and fresh air-dried prints of the tree frog tongue and spleen and young red-eared turtle (ca. 6 g) spleen and heart blood were examined by a quantitative energy-dispersive x-ray microanalysis (X-650, Kevex-7000) for the element constituents of the granules of mast cells and basophils. The specimens were observed by transmission electron microscopy (TEM) (80-200 kV) and followed by scanning transmission electron microscopy (STEM) under an analytical electron microscope (X-650) at an acceleration voltage of 40 kV and a specimen current of 0.2 nA. A spot analysis was performed in a STEM mode for 100 s at a specimen current of 2 nA on the mast cell and basophil granules and other areas of the cells. Histamine was examined by the o-phthalaldehyde method.

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