scholarly journals Chymase released from hypoxia-activated cardiac mast cells cleaves human apoA-I at Tyr192 and compromises its cardioprotective activity

2018 ◽  
Vol 59 (6) ◽  
pp. 945-957 ◽  
Author(s):  
Ilona Kareinen ◽  
Marc Baumann ◽  
Su Duy Nguyen ◽  
Katariina Maaninka ◽  
Andrey Anisimov ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Low Flow ◽  
Human Coronary Artery ◽  
Functional Protein ◽  
Rat Hearts ◽  
Highly Sensitive

ApoA-I, the main structural and functional protein of HDL particles, is cardioprotective, but also highly sensitive to proteolytic cleavage. Here, we investigated the effect of cardiac mast cell activation and ensuing chymase secretion on apoA-I degradation using isolated rat hearts in the Langendorff perfusion system. Cardiac mast cells were activated by injection of compound 48/80 into the coronary circulation or by low-flow myocardial ischemia, after which lipid-free apoA-I was injected and collected in the coronary effluent for cleavage analysis. Mast cell activation by 48/80 resulted in apoA-I cleavage at sites Tyr192 and Phe229, but hypoxic activation at Tyr192 only. In vitro, the proteolytic end-product of apoA-I with either rat or human chymase was the Tyr192-truncated fragment. This fragment, when compared with intact apoA-I, showed reduced ability to promote migration of cultured human coronary artery endothelial cells in a wound-healing assay. We propose that C-terminal truncation of apoA-I by chymase released from cardiac mast cells during ischemia impairs the ability of apoA-I to heal damaged endothelium in the ischemic myocardium.

scholarly journals IgE Enhances Mouse Mast Cell FcεRI Expression In Vitro and In Vivo: Evidence for a Novel Amplification Mechanism in IgE-dependent Reactions

1997 ◽  
Vol 185 (4) ◽  
pp. 663-672 ◽  
Author(s):  
Masao Yamaguchi ◽  
Chris S. Lantz ◽  
Hans C. Oettgen ◽  
Ildy M. Katona ◽  
Tony Fleming ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Immunoglobulin E ◽  
Specific Antigen ◽  
Mast Cell Activation ◽  
Proinflammatory Mediators ◽  
Mouse Mast Cell

The binding of immunoglobulin E (IgE) to high affinity IgE receptors (FcεRI) expressed on the surface of mast cells primes these cells to secrete, upon subsequent exposure to specific antigen, a panel of proinflammatory mediators, which includes cytokines that can also have immunoregulatory activities. This IgE- and antigen-specific mast cell activation and mediator production is thought to be critical to the pathogenesis of allergic disorders, such as anaphylaxis and asthma, and also contributes to host defense against parasites. We now report that exposure to IgE results in a striking (up to 32-fold) upregulation of surface expression of FcεRI on mouse mast cells in vitro or in vivo. Moreover, baseline levels of FcεRI expression on peritoneal mast cells from genetically IgE-deficient (IgE −/−) mice are dramatically reduced (by ∼83%) compared with those on cells from the corresponding normal mice. In vitro studies indicate that the IgE-dependent upregulation of mouse mast cell FcεRI expression has two components: an early cycloheximide-insensitive phase, followed by a later and more sustained component that is highly sensitive to inhibition by cycloheximide. In turn, IgE-dependent upregulation of FcεRI expression significantly enhances the ability of mouse mast cells to release serotonin, interleukin-6 (IL-6), and IL-4 in response to challenge with IgE and specific antigen. The demonstration that IgE-dependent enhancement of mast cell FcεRI expression permits mast cells to respond to antigen challenge with increased production of proinflammatory and immunoregulatory mediators provides new insights into both the pathogenesis of allergic diseases and the regulation of protective host responses to parasites.

scholarly journals Borrelia burgdorferiSpirochetes Induce Mast Cell Activation and Cytokine Release

1999 ◽  
Vol 67 (3) ◽  
pp. 1107-1115 ◽  
Author(s):  
Jeffrey Talkington ◽  
Steven P. Nickell
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Cell Types ◽  
Host Cells ◽  
Mast Cell Activation ◽  
Cytokine Release ◽  
Necrosis Factor Alpha ◽  
Tnf Α

ABSTRACT The Lyme disease spirochete, Borrelia burgdorferi, is introduced into human hosts via tick bites. Among the cell types present in the skin which may initially contact spirochetes are mast cells. Since spirochetes are known to activate a variety of cell types in vitro, we tested whether B. burgdorferi spirochetes could activate mast cells. We report here that freshly isolated rat peritoneal mast cells or mouse MC/9 mast cells cultured in vitro with live or freeze-thawed B. burgdorferi spirochetes undergo low but detectable degranulation, as measured by [5-3H] hydroxytryptamine release, and they synthesize and secrete the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In contrast to findings in previous studies, where B. burgdorferi-associated activity was shown to be dependent upon protein lipidation, mast cell TNF-α release was not induced by either lipidated or unlipidated recombinant OspA. This activity was additionally shown to be protease sensitive and surface expressed. Finally, comparisons of TNF-α-inducing activity in known low-, intermediate-, and high-passage B. burgdorferi B31 isolates demonstrated passage-dependent loss of activity, indicating that the activity is probably plasmid encoded. These findings document the presence in low-passage B. burgdorferi spirochetes of a novel lipidation-independent activity capable of inducing cytokine release from host cells.

Abstract 476: Mast Cell--Mediated Neutrophil Influx Enhances Plaque Progression

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Anouk Wezel ◽  
H Maxime Lagraauw ◽  
Daniël van der Velden ◽  
Saskia C de Jager ◽  
Paul H Quax ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Neutrophil Migration ◽  
Fold Increase ◽  
Mast Cell Activation ◽  
Neutrophil Influx ◽  
Migration Assay ◽  
Cell Activator

Rationale: Activated mast cells have been identified in atherosclerotic plaques. As mast cells have the ability to release chemokines that mediate leukocyte fluxes, we propose that activated mast cells play a pivotal role in leukocyte recruitment during atherosclerosis. Methods and Results: Diet fed B-cell deficient apoE-/-muChain mice, which lack endogenous IgE, received 6 IgE or PBS injections over a period of 8 weeks. Mast cells in the aortic root were significantly more activated after IgE treatment and concomitantly, we detected an increase in plaque size (P=0.050). Intriguingly, a striking increase in the amount of perivascular neutrophils was observed in IgE treated mice (control: 57.6 ± 10.6 neutrophils/mm2 tissue; IgE: 183.0 ± 38.7 neutrophils/mm2 tissue; P=0.01). In order to investigate if activated mast cells can directly attract neutrophils, we injected C57Bl/6 or mast cell deficient Kit(W-sh/W-sh) mice intra-peritoneal with the mast cell activator 48/80. Interestingly, mast cell activation led to a massive neutrophil influx into the peritoneal cavity, while neutrophil numbers in mast cell deficient mice remained unaffected. To confirm these findings, we performed an in vitro migration assay. Indeed, supernatant of activated mast cells caused a 3-fold increase in neutrophil migration (P=0.007). Moreover, addition of anti-CXCR2 to the neutrophils resulted in a major reduction of migration (P=0.03) whereas anti-CXCR4 did not reduce migration significantly. Conclusions: Chemokines released from activated perivascular mast cells induce neutrophil recruitment to the atherosclerotic plaque, thereby aggravating the inflammatory response.

scholarly journals Rhubarb-Evoke Mucus Secretion through Aggregation and Degranulation of Mast Cell in the Colon of Rat: In vivo and ex vivo studies

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Di Wu ◽  
Xiaowei Xue ◽  
Chenchen Gao ◽  
Yuehong Liu ◽  
Tiantian Wang ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Water Content ◽  
Cell Activation ◽  
Ex Vivo ◽  
Mucus Secretion ◽  
Enteric Neurons ◽  
Mast Cell Activation ◽  
Rat Colon

AbstractRhubarb is commonly used to treat constipation in China for its function of promoting intestinal movement and optimum water content in feces. However, its mechanism of mucus secretion is vague. The aim of the study is to investigate the role of mast cells and enteric neurons in rhubarb extract (RE)-induced mucus secretion in the rat colon. Immunofluorescence was used to detect histamine receptors. Western blotting and 3,3′-diaminobenzidine (DAB) were applied to explore the content changes of mast cells activation. The changes in colonic goblet cells (GCs) were determined by means of PAS/AB staining. An intestinal perfusion system with a Bradford protein assay kit was directly to estimate in vitro secretion. And the cytokines were investigated with ELISA. The longitudinal aspect of this study indicate that the number and water content of faecal pellets were enhanced after the administration of different doses of RE accompanied by mast cells accumulated and increased the content of interferon (IFN) -γ or decreased the levels of interleukin (IL) −10 at doses of 3 and 6 g/kg. Pretreatment with ketotifen, mast cell stabilizer, had partially inhibited on RE-induced mucus secretion. Furthermore, RE induced the release of acetylcholine and mucin-2 in the colonic tissue and the histamine levels from the faeces. The results suggest that RE induced colonic mucus secretion involves mast cell activation and some cytokine.

scholarly journals Phospholipase D2 acts as an essential adaptor protein in the activation of Syk in antigen-stimulated mast cells

Blood ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 956-964 ◽  
Author(s):  
Jun Ho Lee ◽  
Young Mi Kim ◽  
Nam Wook Kim ◽  
Jie Wan Kim ◽  
Erk Her ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Adaptor Protein ◽  
Adaptor Proteins ◽  
Mast Cell Activation ◽  
Critical Event ◽  
Phospholipase D1 ◽  
Key Enzyme

Abstract Mast cells are responsible for IgE-mediated allergic reactions. Phospholipase D1 (PLD1) and PLD2 regulate mast cell activation, but the mechanisms remain unclear. Here we show that PLD2 associates with and promotes activation of Syk, a key enzyme in mast cell activation. Antigen stimulation resulted in increased association and colocalization of Syk with PLD2 on the plasma membrane as indicated by coimmunoprecipitation and confocal microscopy. This association was dependent on tyrosine phosphorylation of Syk but not on PLD2 activity. In vitro, PLD2 interacted via its Phox homology (PX) domain with recombinant Syk to induce phosphorylation and activation of Syk. Furthermore, overexpression of PLD2 or catalytically inactive PLD2K758R enhanced antigen-induced phosphorylations of Syk and its downstream targets, the adaptor proteins LAT and SLP-76, while expression of a PLD2 siRNA blocked these phosphorylations. Apparently, the interaction of PLD2 with Syk is an early critical event in the activation of mast cells.

scholarly journals S100A4 Is Critical for a Mouse Model of Allergic Asthma by Impacting Mast Cell Activation

2021 ◽  
Vol 12 ◽  
Author(s):  
Tongqian Wu ◽  
Lan Ma ◽  
Xiaoqian Jin ◽  
Jingjing He ◽  
Ke Chen ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Calcium Binding ◽  
Cell Activation ◽  
Allergic Diseases ◽  
Lavage Fluid ◽  
Mast Cell Activation ◽  
Asthma Model

BackgroundThe calcium-binding protein S100A4 demonstrates important regulatory roles in many biological processes including tumorigenesis and inflammatory disorders such as allergy. However, the specific mechanism of the contribution of S100A4 to allergic diseases awaits further clarification.ObjectiveTo address the effect of S100A4 on the regulation of mast cell activation and its impact on allergy.MethodsBone marrow-derived cultured mast cells (BMMCs) were derived from wild-type (WT) or S100A4-/- mice for in vitro investigation. WT and S100A4-/- mice were induced to develop a passive cutaneous anaphylaxis (PCA) model, a passive systemic anaphylaxis (PSA) model, and an ovalbumin (OVA)-mediated mouse asthma model.ResultsFollowing OVA/alum-based sensitization and provocation, S100A4-/- mice demonstrated overall suppressed levels of serum anti-OVA IgE and IgG antibodies and proinflammatory cytokines in serum, bronchoalveolar lavage fluid (BALF), and lung exudates. S100A4-/- mice exhibited less severe asthma signs which included inflammatory cell infiltration in the lung tissue and BALF, and suppressed mast cell recruitment in the lungs. Reduced levels of antigen reencounter-induced splenocyte proliferation in vitro were recorded in splenocytes from OVA-sensitized and challenged mice that lacked S100A4-/-. Furthermore, deficiency in the S100A4 gene could dampen mast cell activation both in vitro and in vivo, evidenced by reduced β-hexosaminidase release and compromised PCA and PSA reaction. We also provided evidence supporting the expression of S100A4 by mast cells.ConclusionS100A4 is required for mast cell functional activation, and S100A4 may participate in the regulation of allergic responses at least partly through regulating the activation of mast cells.

Abstract 1947: Chymase Inhibition Reduces the Incidence of Intraplaque Hemorrhage and Induces a Stable Atherosclerotic Plaque Phenotype in ApoE Deficient Mice

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Ilze Bot ◽  
Marijke M Westra ◽  
Sandra H van Heiningen ◽  
Hans Hilpert ◽  
Inge M Lankhuizen ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Atherosclerotic Plaque ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Intraplaque Hemorrhage ◽  
Plaque Stability ◽  
Plaque Destabilization

Mast cells are abundantly present in perivascular tissue during atherosclerotic plaque progression and were previously demonstrated to contribute significantly to plaque destabilization. In this study, we aimed to investigate to what extent inhibition of chymase, one of the mast cell proteases, could enhance plaque stability. We demonstrated earlier that the specific chymase inhibitor RO501 (1 μM) was able to quench mast cell activation in vitro , as illustrated by a decreased β-hexosaminidase (−41% and −80%, respectively; P<0.05) as well as chymase activity in the releasate of activated MC/9 and peritoneal mast cells (−71% and −65%, respectively; P<0.05). Next, we assessed whether chymase inhibition was also effective in vivo. Atherosclerotic carotid artery lesions were induced in ApoE −/− mice by perivascular collar placement and mast cells were activated by DNP challenge systemically during lesion development. RO501 (50 mg/kg/day) was administered as diet supplement, leading to serum concentrations of ~2 μM. While plaque size after 6 weeks of treatment did not differ, collagen content of the lesions was 2-fold enhanced in mice treated with RO501 compared to controls (1.4 ± 0.5% and 0.7 ± 0.2%, respectively). This was accompanied by a significant decrease in necrotic core size of the plaques (controls: 52 ± 3% versus RO501: 41 ± 4%, P<0.05). To determine the effects of chymase inhibition after acute mast cell activation in advanced plaques, perivascular mast cells were focally activated in the adventitia of advanced lesions in ApoE −/− mice, which were treated with RO501 as described above. At three days after focal mast cell challenge, the incidence of intraplaque hemorrhage (IPH) was inhibited from 23% in control mice to 4.5% in RO501 treated mice, while also the plaque erythrocyte area was reduced by >90% from 1.2 ± 0.6*10 3 to 0.1 ± 0.08*10 3 μm 2 (P<0.05). Also, we observed a reduction in apoptotic cells (RO501: 0.68 ± 0.20% vs. 1.01 ± 0.36% for IPH negative controls and 1.23 ± 0.42% for IPH + plaques). In conclusion, our data suggest that chymase inhibition at least partly prevents the detrimental effects of perivascular mast cells on plaque stability, identifying chymase inhibition as a new therapeutic approach in the prevention of acute coronary syndromes.

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 Sinomenine potentiates P815 cell degranulation via upregulation of Ca2+ mobilization through the Lyn/PLCγ/IP3R pathway

2016 ◽  
Vol 29 (4) ◽  
pp. 676-683 ◽  
Author(s):  
Nan Wang ◽  
Rui Liu ◽  
Yanping Liu ◽  
Ruirui Zhang ◽  
Langchong He
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Drug Allergy ◽  
Cell Activation ◽  
Mast Cell Activation ◽  
Enzyme Linked Immunosorbent Assay ◽  
Sinomenium Acutum ◽  
Underlying Mechanisms

Mast cells are vital mediators of drug allergy and, therefore, studying the relationship between drug allergy and mast cells is essential. Sinomenine is the principal active component of Sinomenium acutum, which has anti-inflammatory and anti-immune effects, and is used to treat various rheumatoid diseases. However, allergic responses to sinomenine are frequently reported. Therefore, this study assessed the effects of sinomenine on mast cell activation to characterize its allergic effects and the underlying mechanisms. Enzyme-linked immunosorbent assay (ELISA), western blot analyses, and degranulation assays were performed to measure pro-inflammatory and allergic mediators in P815 cells. The allergenic effects of sinomenine were also determined in mice by using active general anaphylaxis (ASA). The results indicated that sinomenine induced inositol-1,4,5-trisphosphate (IP3) production and the release of histamine, interleukin (IL)-6, and endoplasmic reticulum Ca2+ in P815 cells. Furthermore, sinomenine upregulated the phosphorylation of sarcoma (Src), phospholipase C (PLC)-γ1, and IP3 receptor (R). Therefore, sinomenine induced concentration-dependent mast cell activation directly in vitro. Furthermore, our in vivo data identified an appropriate intravenous dose that did not induce these allergic effects, thereby providing information for the potential safe clinical use of sinomenine.

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.

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