scholarly journals TPC1 deficiency or blockade augments systemic anaphylaxis and mast cell activity

2020 ◽  
Vol 117 (30) ◽  
pp. 18068-18078 ◽  
Author(s):  
Elisabeth Arlt ◽  
Marco Fraticelli ◽  
Volodymyr Tsvilovskyy ◽  
Wiebke Nadolni ◽  
Andreas Breit ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Ex Vivo ◽  
Secretory Granules ◽  
Cell Activity ◽  
New Drugs ◽  
Pore Channel ◽  
Systemic Anaphylaxis

Mast cells and basophils are main drivers of allergic reactions and anaphylaxis, for which prevalence is rapidly increasing. Activation of these cells leads to a tightly controlled release of inflammatory mediators stored in secretory granules. The release of these granules is dependent on intracellular calcium (Ca2+) signals. Ca2+release from endolysosomal compartments is mediated via intracellular cation channels, such as two-pore channel (TPC) proteins. Here, we uncover a mechanism for how TPC1 regulates Ca2+homeostasis and exocytosis in mast cells in vivo and ex vivo. Notably, in vivo TPC1 deficiency in mice leads to enhanced passive systemic anaphylaxis, reflected by increased drop in body temperature, most likely due to accelerated histamine-induced vasodilation. Ex vivo, mast cell-mediated histamine release and degranulation was augmented upon TPC1 inhibition, although mast cell numbers and size were diminished. Our results indicate an essential role of TPC1 in endolysosomal Ca2+uptake and filling of endoplasmic reticulum Ca2+stores, thereby regulating exocytosis in mast cells. Thus, pharmacological modulation of TPC1 might blaze a trail to develop new drugs against mast cell-related diseases, including allergic hypersensitivity.

scholarly journals The emerging role of mast cell proteases in asthma

2019 ◽  
Vol 54 (4) ◽  
pp. 1900685 ◽  
Author(s):  
Gunnar Pejler
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Current Knowledge ◽  
Secretory Granules ◽  
Cross Linking ◽  
Lysosomal Hydrolases ◽  
Ige Receptor ◽  
Deficient Mice ◽  
Lines Of Evidence

It is now well established that mast cells (MCs) play a crucial role in asthma. This is supported by multiple lines of evidence, including both clinical studies and studies on MC-deficient mice. However, there is still only limited knowledge of the exact effector mechanism(s) by which MCs influence asthma pathology. MCs contain large amounts of secretory granules, which are filled with a variety of bioactive compounds including histamine, cytokines, lysosomal hydrolases, serglycin proteoglycans and a number of MC-restricted proteases. When MCs are activated, e.g. in response to IgE receptor cross-linking, the contents of their granules are released to the exterior and can cause a massive inflammatory reaction. The MC-restricted proteases include tryptases, chymases and carboxypeptidase A3, and these are expressed and stored at remarkably high levels. There is now emerging evidence supporting a prominent role of these enzymes in the pathology of asthma. Interestingly, however, the role of the MC-restricted proteases is multifaceted, encompassing both protective and detrimental activities. Here, the current knowledge of how the MC-restricted proteases impact on asthma is reviewed.

scholarly journals Reevaluation of reserpine-induced suppression of contact sensitivity. Evidence that reserpine interferes with T lymphocyte function independently of an effect on mast cells.

1985 ◽  
Vol 162 (6) ◽  
pp. 1935-1953 ◽  
Author(s):  
Y A Mekori ◽  
G L Weitzman ◽  
S J Galli
Keyword(s):  
Mast Cell ◽  
T Cell ◽  
Mast Cells ◽  
Cell Activity ◽  
Suppressor Cells ◽  
Intradermal Injection ◽  
Host Cells ◽  
Lymphocyte Function

It has been suggested that reserpine blocks expression of delayed hypersensitivity (DH) by depleting tissue mast cells of serotonin (5-HT), thereby preventing a T cell-dependent release of mast cell 5-HT necessary to localize and to amplify the DH response. However, reserpine blocks expression of DH in mast cell-deficient mice. We therefore decided to reevaluate the mechanism by which reserpine abrogates expression of cellular immunity, and investigated whether the drug might interfere with T cell activity in vitro or in vivo. At concentrations as low as 4 microM, reserpine profoundly suppressed baseline or antigen-augmented levels of [3H]thymidine incorporation by immune lymph node cells obtained from mice sensitized to the contactant oxazolone [I-LNC(Ox)]. This effect was observed both with I-LNC derived from normal mice and with I-LNC derived from congenitally mast cell-deficient W/Wv mice, cell preparations that lacked detectable mast cells, histamine, and 5-HT. Furthermore, treatment of I-LNC with reserpine (20 microM) for 1 h in vitro virtually abolished the ability of these cells to transfer CS to naive mice. This was not a cytolytic effect, as the viability of the I-LNC treated with reserpine was not affected, and washing of the reserpine-treated I-LNC before transfer fully restored their ability to orchestrate a CS response. The action of the drug was not mediated by an effect on mast cells, since the experiment could be performed using mast cell-deficient W/Wv mice as both donors and recipients of I-LNC. In addition, the effect was specific for the treated cells: mice that received reserpine-treated I-LNC(Ox) intravenously together with untreated I-LNC(DNFB) did not develop CS to Ox but responded normally to DNFB; and local intradermal injection of reserpine-treated I-LNC(Ox) which failed to transfer reactivity to Ox, did not interfere with the development of CS to DNFB at the same site. Finally, cotransfer experiments indicated that the effect of reserpine on the transfer of CS was not due to activation of suppressor cells. Our findings strongly suggest that whatever effects reserpine might have on immunologically nonspecific host cells, the drug's effects on sensitized T cells are sufficient to explain its ability to block cell-mediated immune responses in vivo.

scholarly journals AK002, a Novel Humanized Monoclonal Antibody to Siglec-8, Inhibits Mast Cell Activity and Depletes Eosinophils in Ex Vivo Bone Marrow Tissue from Patients with Systemic Mastocytosis

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1104-1104 ◽  
Author(s):  
Bradford A Youngblood ◽  
Emily C Brock ◽  
John Leung ◽  
Alan T Chang ◽  
Christopher Bebbington ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Bone Marrow ◽  
Flow Cytometry ◽  
Mast Cell ◽  
Mast Cells ◽  
Ex Vivo ◽  
Systemic Mastocytosis ◽  
Cell Activity ◽  
Receptor Expression ◽  
Long Term Treatment

Abstract INTRODUCTION: Systemic Mastocytosis (SM) is a rare disease characterized by the clonal proliferation and accumulation of mast cells in the bone marrow, respiratory and gastrointestinal tracts, and organs such as the skin, liver, spleen, and brain. Common symptoms include pruritus, flushing, headache, cognitive impairment, fatigue, diarrhea, abdominal pain, hypotension and skin lesions, as well as an increased risk for osteoporosis and anaphylaxis. SM is currently managed with antihistamines, cromolyn sodium, and leukotriene blocking agents, which lack specificity and efficacy. In addition, glucocorticoids can provide temporary relief in some cases; however long-term treatment with steroids is not appropriate due to their many side effects. Siglec-8 is an inhibitory receptor selectively expressed on human mast cells and eosinophils, and therefore represents a novel target for the treatment of SM. Antibodies to Siglec-8 have been shown to inhibit mast cell activity and induce apoptosis of eosinophils. AK002 is a novel, humanized, non-fucosylated IgG1 monoclonal antibody to Siglec-8. This study evaluates the expression of Siglec-8 and ex vivo activity of AK002 on mast cells and eosinophils in bone marrow biopsies from patients with SM. METHODS: Bone marrow aspirates were obtained from patients clinically diagnosed with SM and processed to remove red blood cells. Multi-color flow cytometry was used to quantify eosinophils and mast cells and to evaluate the activation state of mast cells. The ex vivo activity of AK002 against eosinophils and mast cells was evaluated by flow cytometry. The inhibitory activity of AK002 agaist mast cells was also examined by quantifying cytokine levels in cultured bone marrow aspirate supernatants. RESULTS: All mast cells and eosinophils in bone marrow aspirates from SM patients displayed high Siglec-8 receptor expression (Figure 1). These mast cells also expressed the SM specific markers, CD25 (Figure 1) and CD30 and increased levels of cell surface degranulation markers. The expression of CD25 on mast cells significantly decreased following overnight treatment with AK002. AK002 also significantly reduced the level of mast cell-associated cytokines produced in cultured bone marrow supernatants, including IL-6, IL-8, and TNFα (Figure 2A). These changes in mast cell activity after AK002 treatment were not due to a reduction in mast cell numbers. In contrast, overnight incubation of AK002 significantly reduced the number of bone marrow eosinophils compared to an isotype control (Figure 2B). CONCLUSIONS: Bone marrow aspirates from patients with SM had activated mast cells and eosinophils that displayed robust expression of Siglec-8. AK002 demonstrated SM mast cell inhibition in ex vivo bone marrow aspirates. AK002 also had depleting effects on eosinophils, which may be valuable to SM patients with associated eosinophilia. These encouraging results could represent a novel approach for the treatment of SM. Disclosures Youngblood: Allakos, Inc.: Employment. Brock:Allakos, Inc.: Employment. Leung:Allakos, Inc.: Employment. Chang:Allakos, Inc.: Employment. Bebbington:Allakos, Inc.: Employment. Tomasevic:Allakos, Inc.: Employment.

scholarly journals SWAP-70 Regulates c-kit-Induced Mast Cell Activation, Cell-Cell Adhesion, and Migration

2004 ◽  
Vol 24 (23) ◽  
pp. 10277-10288 ◽  
Author(s):  
Raja Rajeswari Sivalenka ◽  
Rolf Jessberger
Keyword(s):  
Mast Cell ◽  
Cell Adhesion ◽  
Mast Cells ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Calcium Flux ◽  
Mutant Cells

ABSTRACT SWAP-70, an unusual phosphatidylinositol-3-kinase-dependent protein that interacts with the RhoGTPase Rac, is highly expressed in mast cells. Cultured bone marrow mast cells (BMMC) from SWAP-70−/− mice are reduced in FcεRI-triggered degranulation. This report describes the hitherto-unknown role of SWAP-70 in c-kit receptor signaling, a key proliferation and differentiation pathway in mast cells. Consistent with the role of Rac in cell motility and regulation of the actin cytoskeleton, mutant cells show abnormal actin rearrangements and are deficient in migration in vitro and in vivo. SWAP-70−/− BMMC are impaired in calcium flux, in proper translocation and activity of Akt kinase (required for mast cell activation and survival), and in translocation of Rac1 and Rac2 upon c-kit stimulation. Adhesion to fibronectin is reduced, but homotypic cell association induced through c-kit is strongly increased in SWAP-70−/− BMMC. Homotypic association requires extracellular Ca2+ and depends on the integrin αLβ2 (LFA-1). ERK is hyperactivated upon c-kit signaling in adherent and dispersed mutant cells. Together, we suggest that SWAP-70 is an important regulator of specific effector pathways in c-kit signaling, including mast cell activation, migration, and cell adhesion.

scholarly journals Role of mucosal mast cells in early vascular permeability changes of intestinal DTH reaction in the rat

1998 ◽  
Vol 274 (5) ◽  
pp. G832-G839 ◽  
Author(s):  
Aletta D. Kraneveld ◽  
Thea Muis ◽  
Andries S. Koster ◽  
Frans P. Nijkamp
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Vascular Leakage ◽  
Mast Cell Activation ◽  
Mucosal Mast Cell ◽  
Mucosal Mast Cells

Previously, it was shown that depletion and stabilization of the mucosal mast cell around the time of challenge were very effective in reducing delayed-type hypersensitivity (DTH) reactions in the small intestine of the rat. The role of mucosal mast cells in the early component of intestinal DTH reaction was further investigated in this study. In vivo small intestinal vascular leakage and serum levels of rat mast cell protease II (RMCP II) were determined within 1 h after intragastric challenge of rats that had been sensitized with dinitrobenzene 5 days before. A separate group of rats was used to study vasopermeability in isolated vascularly perfused small intestine after in vitro challenge. To investigate the effects of mast cell stabilization on the early events of the DTH reaction, doxantrazole was used. The influence of sensory nerves was studied by means of neonatal capsaicin-induced depletion of sensory neuropeptides. Within 1 h after challenge, a significant increase in vascular permeability was found in vivo as well as in vitro. This was associated with a DTH-specific increase in RMCP II in the serum, indicating mucosal mast cell activation. In addition, doxantrazole treatment and caspaicin pretreatment resulted in a significant inhibition of the DTH-induced vascular leakage and an increase in serum RMCP II. These findings are consistent with an important role for mucosal mast cells in early vascular leakage changes of intestinal DTH reactions. In addition, sensory nervous control of mucosal mast cell activation early after challenge is demonstrated.

Heparanase-mediated cleavage of macromolecular heparin accelerates release of granular components of mast cells from extracellular matrices

2014 ◽  
Vol 458 (2) ◽  
pp. 291-299 ◽  
Author(s):  
Nobuaki Higashi ◽  
Michihiko Waki ◽  
Mayumi Sue ◽  
Yusuke Kogane ◽  
Hiroaki Shida ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Connective Tissue ◽  
Cell Function ◽  
Secretory Granules ◽  
Extracellular Matrices ◽  
Regulatory Role ◽  
Tissue Type ◽  
Size Dependent

Connective tissue-type mast cells express heparin and heparanase in the secretory granules. Cleavage of granular heparin by heparanase accelerates release of granular components from collagen-based extracellular matrices. A size-dependent novel regulatory role of heparin for mast cell function is proposed.

Inhibition of thrombosis in melanoma allografts in mice by endogenous mast cell heparin

2003 ◽  
Vol 90 (08) ◽  
pp. 351-360 ◽  
Author(s):  
Mark Corwin ◽  
Hon Yu ◽  
Jun Wang ◽  
Orhan Nalcioglu ◽  
Min-Ying Su ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Malignant Melanoma ◽  
Knockout Mice ◽  
B16 Melanoma ◽  
Targeted Disruption ◽  
Gene Coding ◽  
High Degree

SummaryAn unexplained paradox of malignant melanoma is the apparent failure of the blood within the tumor to clot despite the presence of multiple factors that should promote blood clotting. Here we present histochemical evidence that human and murine melanomas are extensively infiltrated by abundant mast cells. Because mast cells contain the natural anticoagulant heparin, the present studies were aimed at defining the role of mast cell heparin in preventing the blood from clotting within B16 melanoma grafts in C57BL/6 J mice. Mice bearing B16 melanoma grafts were treated with non-specific or specific inhibitors of mast cell heparin (protamine or heparinase, respectively). After the drug treatment there was histologic and functional evidence of selective thrombosis of the blood vessels within the protamine and heparinase treated melanoma grafts. A similar, high degree of thrombosis was also observed in B16 tumors grown in transgenic NDST-2 knockout mice bearing a targeted disruption in the gene coding for mast cell heparin synthesis. The tumors grown in the protamine-treated animals were significantly smaller than the tumors from control (untreated mice). By contrast, the tumors treated with heparinase or grown in the NDST-2 knockout mice were significantly larger than the tumors from control (untreated) mice. We conclude that the intrinsic procoagulant properties of malignant melanoma are neutralized in vivo by the anticoagulant properties of endogenous heparin produced by mast cells that naturally infiltrate the tumor. Our results also suggest that thrombosis and hemostasis within melanoma may play a complex role in modulating the growth of the tumor.

scholarly journals Protein Disulfide Isomerases Regulate IgE-Mediated Mast Cell Responses and Their Inhibition Confers Protective Effects During Food Allergy

2020 ◽  
Vol 11 ◽  
Author(s):  
Dylan Krajewski ◽  
Stephanie H. Polukort ◽  
Justine Gelzinis ◽  
Jeffrey Rovatti ◽  
Edwin Kaczenski ◽  
...  
Keyword(s):  
Mast Cell ◽  
Food Allergy ◽  
Mast Cells ◽  
Cell Activation ◽  
Cell Activity ◽  
Mast Cell Activation ◽  
Protective Effects ◽  
Ige Mediated ◽  
Protein Disulfide

The thiol isomerase, protein disulfide isomerase (PDI), plays important intracellular roles during protein folding, maintaining cellular function and viability. Recent studies suggest novel roles for extracellular cell surface PDI in enhancing cellular activation and promoting their function. Moreover, a number of food-derived substances have been shown to regulate cellular PDI activity and alter disease progression. We hypothesized that PDI may have similar roles during mast cell-mediated allergic responses and examined its effects on IgE-induced mast cell activity during cell culture and food allergy. Mast cells were activated via IgE and antigen and the effects of PDI inhibition on mast cell activation were assessed. The effects of PDI blockade in vivo were examined by treating mice with the irreversible PDI inhibitor, PACMA-31, in an ovalbumin-induced model of food allergy. The role of dietary PDI modulators was investigated using various dietary compounds including curcumin and quercetin-3-rutinoside (rutin). PDI expression was observed on resting mast cell surfaces, intracellularly, and in the intestines of allergic mice. Furthermore, enhanced secretion of extracellular PDI was observed on mast cell membranes during IgE and antigen activation. Insulin turbidimetric assays demonstrated that curcumin is a potent PDI inhibitor and pre-treatment of mast cells with curcumin or established PDI inhibitors such as bacitracin, rutin or PACMA-31, resulted in the suppression of IgE-mediated activation and the secretion of various cytokines. This was accompanied by decreased mast cell proliferation, FcεRI expression, and mast cell degranulation. Similarly, treatment of allergic BALB/c mice with PACMA-31 attenuated the development of food allergy resulting in decreased allergic diarrhea, mast cell activation, and fewer intestinal mast cells. The production of TH2-specific cytokines was also suppressed. Our observations suggest that PDI catalytic activity is essential in the regulation of mast cell activation, and that its blockade may benefit patients with allergic inflammation.

scholarly journals The BH3-only protein Puma plays an essential role in cytokine deprivation–induced apoptosis of mast cells

Blood ◽  
2007 ◽  
Vol 110 (9) ◽  
pp. 3209-3217 ◽  
Author(s):  
Maria Ekoff ◽  
Thomas Kaufmann ◽  
Maria Engström ◽  
Noboru Motoyama ◽  
Andreas Villunger ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Essential Role ◽  
Wild Type ◽  
Cell Numbers ◽  
Growth Factor Deprivation ◽  
Induced Apoptosis ◽  
Cytokine Deprivation

Abstract Mast cells play critical roles in the regulation of inflammation. One characteristic feature of mast cells is their relatively long lifespan in vivo. Members of the Bcl-2 protein family are regulators of cell survival and apoptosis, where the BH3-only proteins are critical proapoptotic proteins. In this study we investigated the role of the BH3-only proteins Noxa, Bad, Bim, Bmf, Bid, and Puma in apoptosis of mucosal-like mast cells (MLMCs) and connective tissue–like mast cells (CTLMCs). We demonstrate that Puma is critical for the induction of mast-cell death following cytokine deprivation and treatment with the DNA-damaging agent etoposide in MLMCs and CTLMCs. Using p53−/− mast cells, we found that cytokine deprivation–induced apoptosis, in contrast to that elicited by etoposide, is p53-independent. Interestingly, mast cells deficient in FOXO3a, previously proposed as a transcription factor for Puma induction in response to growth factor deprivation, were markedly resistant to cytokine withdrawal compared with wild-type cells. Moreover, overexpression of phosphorylation-deficient, constitutively active FOXO3a caused an up-regulation of Puma. In conclusion, our data demonstrate a pivotal role for Puma in the regulation of cytokine deprivation–induced mast-cell apoptosis and suggest a plausible role for Puma in the regulation of mast cell numbers in vivo.

scholarly journals The Role of Mast Cell Specific Chymases and Tryptases in Tumor Angiogenesis

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Devandir Antonio de Souza Junior ◽  
Ana Carolina Santana ◽  
Elaine Zayas Marcelino da Silva ◽  
Constance Oliver ◽  
Maria Celia Jamur
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Tumor Growth ◽  
Tumor Angiogenesis ◽  
Secretory Granules ◽  
Therapeutic Targets ◽  
Exact Role ◽  
Mast Cell Granule ◽  
Novel Therapeutic

An association between mast cells and tumor angiogenesis is known to exist, but the exact role that mast cells play in this process is still unclear. It is thought that the mediators released by mast cells are important in neovascularization. However, it is not known how individual mediators are involved in this process. The major constituents of mast cell secretory granules are the mast cell specific proteases chymase, tryptase, and carboxypeptidase A3. Several previous studies aimed to understand the way in which specific mast cell granule constituents act to induce tumor angiogenesis. A body of evidence indicates that mast cell proteases are the pivotal players in inducing tumor angiogenesis. In this review, the likely mechanisms by which tryptase and chymase can act directly or indirectly to induce tumor angiogenesis are discussed. Finally, information presented here in this review indicates that mast cell proteases significantly influence angiogenesis thus affecting tumor growth and progression. This also suggests that these proteases could serve as novel therapeutic targets for the treatment of various types of cancer.

Sign in / Sign up

Export Citation Format

Share Document