Mast Cell Granules Research Articles

Localization of anionic constituents in mast cell granules of brachymorphic (bm/bm) mice by using avidin-conjugated colloidal gold

We used the egg avidin gold complex as a polycationic probe for the localization of negatively charged sites in the secretory granules of mouse mast cells. We compared the binding of this reagent to mast cell granules in wild-type mice and in congenic brachymorphic mice in which mast cell secretory granules contained undersulfated proteoglycans. We localized anionic sites by post-embedding labeling of thin sections of mouse skin and tongue tissues fixed in Karnovsky's fixative and OsO(4) and embedded in Araldite. Transmission electron microscopy revealed that the mast cell granules of bm/bm mice had a lower optical density than those of wild-type mice (P<0.001) and a lower avidin gold binding density (by approximately 50%, P<0.001). The latter result provided additional evidence that the contents of mast cell granules in bm/bm mice were less highly sulfated than in those of wild-type mice. In both wild-type and bm/bm mast cells, the distribution of granule equivalent volumes was multimodal, but the unit granule volume was approximately 19% lower in bm/bm cells than in wild-type cells (P<0.05). Thus, bm/bm mast cells develop secretory granules that differ from those of wild-type mice in exhibiting a lower optical density and slightly smaller unit granules, however the processes that contribute to granule maturation and granule-granule fusion in mast cells are operative in bm/bm cells.

Inflammation and apoptosis induced by mastoparan Polybia-MPII on skeletal muscle

Mastoparan firstly described as an inducer of mast cell granules exocytosis has been also related to many essential mechanisms of cell function. In skeletal muscle tissue the best characterization of mastoparan effect was induction of myonecrosis. We examined the ability of mastoparan Polybia-MPII from Polybia paulista wasp venom to induce apoptosis and inflammation in mouse tibial anterior muscle. The activation of caspase 3 and 9, the expression of TNF-α, IFN-γ, CD68 and CD163 proteins, specific of resident and migrant macrophages, respectively, were examined (3 h to 21 d). TUNEL-positive nuclei were found both in damaged and normal-looking muscle fibres, whereas the caspases, cytokines and macrophages proteins were only in damaged fibres. The caspase 3 and 9 expression and the immunolabelled areas of TNF-α and IFN-γ were significantly higher compared to control. TUNEL-positive nuclei and TNF-α expression were also present in regenerating fibres. CD68 and CD163 signalize necrotic debris removal, release of chemo-attractants and cytokines which have been considered a pre-requisite for muscle regeneration. High levels of cytokines coincided with the intense muscle proteolysis by mastoparan (3–24 h) and the climax of regeneration (3 d) whereas cytokines decline corresponded to periods of tissue remodeling and intense fibre protein synthesis (7–21 d). We conclude that the mastoparan Polybia-MPII causes myonecrosis and apoptosis, the latter probably involving caspases signalling, corroborated by mitochondrial damage, and cytokines activation.

Feline intestinal sclerosing mast cell tumour: 50 cases (1997-2008)

This case series presents a unique and unreported variant of feline intestinal mast cell tumour recognized at the CSU Veterinary Diagnostic Laboratory. Fifty cases of feline intestinal mast cell tumours described as having a significant stromal component were reviewed. Neoplastic cells formed a trabecular pattern admixed with moderate to abundant dense stromal collagen (sclerosis). Neoplastic cells had poorly discernible intracytoplasmic granules which demonstrated metachromasia with special histochemical stains consistent with mast cell granules. Additionally, a subset of cases stained for mast cell-specific tryptase and c-kit demonstrated positive immunoreactivity. Eosinophilic infiltrates were moderate to marked in almost all cases. Lymph node and hepatic metastases were present in 66% of the cases. Treatment and clinical outcome was available in 25/50 cases. Twenty-three of these patients died or were euthanized within 2 months of initial diagnosis. This is the first case series to characterize a sclerosing variant of intestinal mast cell tumour in the cat which appears to have a high propensity for metastasis and a guarded prognosis.

Hematoxylin shortages: their causes and duration, and other dyes that can replace hemalum in routine hematoxylin and eosin staining

The origins of repeated hematoxylin shortages are outlined. Lack of integration in the hematoxylin trade exacerbates the problems inherent in using a natural product. Separate corporations are engaged in tree growth and harvesting, dye extraction, processing of extracts to yield hematoxylin, and formulation and sale of hematoxylin staining solutions to the end users in biomedical laboratories. Hematoxylin has many uses in biological staining and no single dye can replace it for all applications. Probably, the most satisfactory substitutes for aluminum-hematoxylin (hemalum) are the ferric complexes of celestine blue (CI 51050; mordant blue 14) and eriochrome cyanine R (CI 43820; mordant blue 3, also known as chromoxane cyanine R and solochrome cyanine R). The iron-celestine blue complex is a cationic dye that binds to nucleic acids and other polyanions, such as those of cartilage matrix and mast cell granules. Complexes of iron with eriochrome cyanine R are anionic and give selective nuclear staining similar to that obtained with acidic hemalum solutions. Iron complexes of gallein (CI 45445; mordant violet 25), a hydroxyxanthene dye, can replace iron-hematoxylin in formulations for staining nuclei, myelin, and protozoa.

Histochemical method for demonstrating quail mast cell types simultaneously

The development and application of selective staining methods for routine detection of mast cells are of considerable interest, because these cells play an important role in health and disease. The composition of cytoplasmic mast cell granules depends on the species and type of mast cell. The study reported here was conducted to investigate the combined use of aldehyde fuchsin (AF) and the Alcian blue-critical electrolyte concentration (AB-CEC) (pH 5.8, 0.3 M MgCl2) techniques for differentiating avian mast cell subtypes. Tissue samples from skin, intestines, and lungs of six healthy adult quail and two control rats were fixed in Carnoy's solution and 10% formolin for routine histological processing. To determine the staining properties of sulfated glycosaminoglycans (GAGs), a three-step staining technique was applied using berberine sulfate, AF, and AB-CEC. In quail, AF positivity following application of the AB-CEC technique was found only in the lungs, mostly in cells that gave a berberine sulfate-positive reaction, and this positivity was determined to be localized particularly in the nucleus and perinuclear cytoplasm. In other regions, the pale AF staining of cells that did not emit fluorescence when stained with berberine sulfate was determined to be replaced by a blue color after application of AB-CEC. The AF/AB-CEC (pH 5.8, 0.3 M MgCl2) technique demonstrated that rat and quail mast cells varied in both GAG types and their distribution within the cell. Especially in avian species, this technique can be applied to distinguish mast cells according to their GAG content. It can be used as an alternative to the AB/safranin O staining procedure for differentiating mast cells that contain and lack heparin.

Mast Cells Positive to Tryptase Correlate with Angiogenesis in Early Breast Cancer.

Abstract Background: Literature data indicate that mast cells (MCs) are involved in tumor angiogenesis due to the release of several pro-angiogenetic factor among which tryptase, a serine protease stored in MCs granules, is one of the most active. In benign breast lesions and in primary breast cancer, tryptase-positive MCs are more numerous as compared to chymase-positive MCs. Recently, it has been demonstrated that tryptase-positive MCs are involved in angiogenesis in sentinel lymph nodes with micrometastases from patients with breast cancer. However no data has been published regarding the correlations between MCs positive to tryptase and angiogenesis in primary breast cancer tissue. In the present study, we have evaluated the correlations between the number of MCs positive to tryptase (MCDPT), the area occupied by MCs positive to tryptase (MCAPT), microvascular density (MVD) and endothelial area (EA) in a series of T1-3, N0-2, MO female breast cancer, by means of immunohistochemistry and image analysis methods.Material and Methods: Bioptic specimens were collected from 88 female breast cancer patients who had undergone breast cancer surgery. For the evaluation of MCDPT, MCAPT, MVD and EA, a three layer biotin-avidin-peroxidase system was utilized. Briefly, six-micrometers thick serial sections of formalin-fixed and paraffin-embedded bioptic tumor samples were obtained. Then sections were microwaved at 500 W for 10 min. and treated with a 3% hydrogen peroxide solution. Sections were incubated with human-specific monoclonal antibodies anti-CD34 (QB-END 10; Bio-Optica Milan, Italy) diluted 1:50 for 1h at room temperature and anti-tryptase (clone AA1; Dako, Glostrup, Denmark) diluted 1:100 for 1h at room temperature. The bound antibody was visualised using biotinylated secondary antibody, avidin-biotin peroxidase complex, and and 3-amino-9-ethylcarbazole. The five most vascularized areas ("hot spot") were selected at low magnification and both individual vessels were counted at x 400 magnification. In serial sections each single tryptase-positive MC was counted. Single brown stained endothelial cells and red MCs positive to tryptase were also evaluated in terms of immunostained area at x 400 magnification.Results: Our data demonstrated a significantly (r= ranging from 0.78 to 0.89; p: ranging from 0.001 to 0.002 by Pearson's analysis respectively) correlation between MCDPT, MCAPT, MVD, EA each to other, whereas no correlation concerning MCDPT, MCAPT, MVD, EA and the main clinical pathological features was found.Discussion: These preliminary results suggest that tryptase-positive MC play a key role in breast cancer angiogenesis and that inhibition of tryptase may be a new antiangiogenic strategy for the treatment of breast cancer. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2159.

Mast Cell Differentiation and Activation Is Closely Linked to Expression of Genes Coding for the Serglycin Proteoglycan Core Protein and a Distinct Set of Chondroitin Sulfate and Heparin Sulfotransferases

Serglycin (SG) proteoglycan consists of a small core protein to which glycosaminoglycans of chondroitin sulfate or heparin type are attached. SG is crucial for maintaining mast cell (MC) granule homeostasis through promoting the storage of various basic granule constituents, where the degree of chondroitin sulfate/heparin sulfation is essential for optimal SG functionality. However, the regulation of the SG core protein expression and of the various chondroitin sulfate/heparin sulfotransferases during MC differentiation and activation are poorly understood. Here we addressed these issues and show that expression of the SG core protein, chondroitin 4-sulfotransferase (C4ST)-1, and GalNAc(4S)-6-O-sulfotransferase (GalNAc4S6ST) are closely linked to MC maturation. In contrast, the expression of chondroitin 6-sulfotransferase correlated negatively with MC maturation. The expression of N-deacetylase/N-sulfotransferase (NDST)-2, a key enzyme in heparin synthesis, also correlated strongly with MC maturation, whereas the expression of the NDST-1 isoform was approximately equal at all stages of maturation. MC activation by either calcium ionophore or IgE ligation caused an up-regulated expression of the SG core protein, C4ST-1, and GalNAc4S6ST, accompanied by increased secretion of chondroitin sulfate as shown by biosynthetic labeling experiments. In contrast, NDST-2 was down-regulated after MC activation, suggesting that MC activation modulates the nature of the glycosaminoglycan chains attached to the SG core protein. Taken together, these data show that MC maturation is associated with the expression of a distinct signature of genes involved in SG proteoglycan synthesis, and that MC activation modulates their expression.

Zinc lozenges as cure for the common cold – A review and hypothesis

SummaryA 7-day reduction in duration of common colds was shown by Eby et al. in 1984 using 23 mg zinc gluconate throat lozenges. Over the following 25 years, 14 double-blind, placebo-controlled, randomized clinical trials produced widely differing results with about one-half showing success and the remainder showing failure. Positively charged, ionic zinc (iZn), but not bound zinc, is strongly astringent, antirhinoviral, increases interferon-gamma (IFN-γ) 10-fold, inhibits intercellular adhesion molecule-1 (ICAM-1) and inhibits the release of vasoactive ingredients from mast cell granules. Solution equilibrium chemistry analytical techniques showed lozenge iZn fraction varying from 0% to 100% of total lozenge zinc between trials, with zinc acetate (ZA) releasing 100% iZn, zinc gluconate (ZG) releasing 72% iZn and other zinc compounds releasing much less or none at physiologic pH 7.4. Since only iZn has in vitro benefits, iZn variations are hypothesized to have produced the widely varying clinical results. In support of the iZn hypothesis, lozenge iZn and total daily iZn in trials were found highly correlated with reductions in common cold durations with statistical significance for mean duration (P < 0.001) and median duration (P < 0.004), while total zinc (iZn plus bound) showed no correlation with changes in duration. Duration reductions (mean 0 days, median 0.43 days) for multi-ligand ZG and ZA lozenges differed significantly from duration reductions (mean 3.37 days, median 2.9 days) for single ligand ZA and ZG lozenges (P < 0.001) showing that additive ligands as flavor-masks damaged or eliminated efficacy. Five of 6 trials with lozenges whose zinc compositions had a first stability constant of 1.7 or less succeeded, while only 2 of 9 trials of lozenges with higher stability succeeded (P < 0.02). From the strong, multiple statistical relationships found, it is inferred that iZn is the active ingredient in zinc lozenges for colds, as it is in vitro against rhinoviruses, and that solution chemistry analytical techniques used at physiological pH are correct means for lozenge iZn analysis. Zinc lozenges slowly dissolving in the mouth over a 20–30 min period releasing adequate iZn (⩾18 mg) used each 2 h are hypothesized to shorten common colds by 6–7 days, which is a cure for the common cold. Due to inadequate lozenge iZn very few of more than 40 different brands of zinc lozenges on the US market are expected to have any effect on the duration or severity of common colds.

Mouse Mast Cell Protease 4 Is the Major Chymase in Murine Airways and Has a Protective Role in Allergic Airway Inflammation

It is widely established that mast cells (MCs) have a harmful role in asthma, for example by secreting various proinflammatory substances stored within their secretory granule. However, in this study, we show that one of the substances stored within MC granule, chymase, in fact has a protective role in allergic airway inflammation, indicating that MCs may possess both harmful and protective activities in connection with this type of disease. Wild-type (WT) mice and mice lacking mouse MC protease 4 (mMCP-4), a chymase that is functionally homologous to human chymase, were sensitized and challenged with OVA, followed by the assessment of airway physiology and inflammatory parameters. Our results show that the airway hyperresponsiveness was significantly higher in mMCP-4(-/-) as compared with WT mice. Moreover, the degree of lung tissue inflammation was markedly higher in mice lacking mMCP-4 than in WT controls. Histological analysis revealed that OVA sensitization/challenge resulted in a marked increased in the thickness of the smooth muscle cell (SMC) layer and, notably, that the degree of SMC layer thickening was more pronounced in mMCP-4(-/-) animals than in WT controls, thus indicating that chymase may have an effect on airway SMCs. In support of this, mMCP-4-positive MCs were located in the close vicinity of the SMC layer, mainly in the upper airways, and mMCP-4 was shown to be the major chymase expressed in these MCs. Taken together, our results indicate that chymase present in the upper airways protects against allergic airway responses, possibly by regulating SMCs.

T-cell receptor repertoire diversity improves after intramyocardial injection of bone marrow cells in patients with severe coronary artery disease

Background: Mast cells are multifunctional cells containing various mediators, such as cytokines, proteases, and histamine. Recent studies have shown that mast cells can affect disease progression after acute myocardial infarction. Here, we evaluated the effects of mast cell granules (MCGs) at different concentrations on various cell types, such as rat neonatal cardiomyocytes (rCMs), human endothelial progenitor cells (hEPCs), and human umbilical vein endothelial cells (hUVECs), and in a rat model of myocardial infarction. Methods and Results: In the in vitro assay, we treated rCMs, hEPCs, and hUVECs with MCGs [1%, 0.1%, 0.01%, and 0.001% of the original dose (2×105 cells/ml)] for 4 or 24 h. In the in vivo assay, we injected MCGs (2 or 20 μl) into an infarcted rat heart. We analyzed cell survival, cell signals, angiogenesis, and preservation of left ventricular function. MCGs increased capillary tube formation and migration in hEPCs and hUVECs, and phosphorylation of Akt and ERK in rCMs. In the rat model, both 2 and 20 μl MCGs increased capillary density in the infarct area to three times that in the control rats (Pb.05 in each). Left ventricular function improved in the group treated with 2 μl MCGs (Pb.05). Conclusions: MCGs play a role in the regulation of angiogenesis and cell survival and may result in improved left ventricular function after myocardial infarction.

Mast cell granules regulate angiogenesis and cell survival in a myocardial infarction rat model

Mast cell granules regulate angiogenesis and cell survival in a myocardial infarction rat model

Expression of Antizyme Inhibitor 2 in Mast Cells and Role of Polyamines as Selective Regulators of Serotonin Secretion

BackgroundUpon IgE-mediated activation, mast cells (MC) exocytose their cytoplasmic secretory granules and release a variety of bioactive substances that trigger inflammatory responses. Polyamines mediate numerous cellular and physiological functions. We report here that MCs express antizyme inhibitor 2 (AZIN2), an activator of polyamine biosynthesis, previously reported to be exclusively expressed in the brain and testis. We have investigated the intracellular localization of AZIN2 both in resting and activated MCs. In addition, we have examined the functional role of polyamines, downstream effectors of AZIN2, as potential regulators of MC activity.Methodology/Principal FindingsImmunostainings show that AZIN2 is expressed in primary and neoplastic human and rodent MCs. We demonstrate that AZIN2 localizes in the Vamp-8 positive, serotonin-containing subset of MC granules, but not in tryptase-containing granules, as revealed by double immunofluorescence stainings. Furthermore, activation of MCs induces rapid upregulation of AZIN2 expression and its redistribution, suggesting a role for AZIN2 in secretory granule exocytosis. We also demonstrate that release of serotonin from activated MCs is polyamine-dependent whereas release of histamine and β-hexosaminidase is not, indicating a granule subtype-specific function for polyamines.Conclusions/SignificanceThe study reports for the first time the expression of AZIN2 outside the brain and testis, and demonstrates the intracellular localization of endogenous AZIN2 in MCs. The granule subtype-specific expression and its induction after MC activation suggest a role for AZIN2 as a local, in situ regulator of polyamine biosynthesis in association with serotonin-containing granules of MCs. Furthermore, our data indicates a novel function for polyamines as selective regulators of serotonin release from MCs.

Contribution of mast cells to the oedema induced by Bothrops moojeni snake venom and a pharmacological assessment of the inflammatory mediators involved

The ability of Bothrops moojeni venom (BmV) to induce oedema in mice, the involvement of principal inflammatory mediators and mast cells (MCs) were investigated. The intraplantar injection of BmV (0.3–6 μg/paw) caused a dose- and time-dependent oedema with a peak between 30 and 60 min after venom injection (0.3–1 μg/paw), disappearing within 24 h. Either MCs granule inhibition or depletion by cromoglycate or C48/80, respectively, markedly reduced BmV-induced oedema. MCs depletion by imatinib also reduced oedema. Intraperitoneal BmV injection (2.5–10 μg/site) induced MCs degranulation and release of PGD 2. Treatment with promethazine, cimetidine or thioperamide, histamine H1, H2 and H3/H4 receptor antagonists, respectively, markedly reduced the initial phase of oedema. Combined treatment with these antagonists further reduced, but not abrogated oedema. Indomethacin or eterocoxib (cyclooxygenase inhibitors) reduced oedema until 180 min, whereas zileuton (lipoxygenase inhibitor) affected this event until 60 min. Dexamethazone caused a long lasting reduction of oedema. However, L-NAME and aminoguanidine (NO synthase inhibitors) significantly increased BmV-induced oedema. In conclusion, BmV induces oedema, mediated by MCs degranulation, histamine by H1, H2, H3/H4 receptors, prostaglandins and leukotrienes, and down-regulated by NO. Partial neutralization of oedema was observed even when polyspecific bothropic antivenom was injected immediately after venom.

MMP-9 and CD68+ cells are required for tissue remodeling in response to natural hydroxyapatite

Large bone defects represent major clinical problems in the practice of reconstructive orthopedic and craniofacial surgery. The aim of this study was to examine, through immunohistochemistry approach, the involvement of MMP-9 and CD68(+) cells during tissue remodeling in response to natural hydroxyapatite (HA) implanted in rat subcutaneous tissue. Before experimentation, forty animals were randomly distributed into two experimental groups: Group-I (Gen-Ox micro-granules) and Group-II (Gen-Ox macro-granules). Afterwards, the biopsies were collected after 10, 20, 30, and 60 days post-implantation. Our results showed that at 10 days, a low-renewal foreign body type granuloma formation was observed in most of the cases. Macrophage- and fibroblast-like cells were the predominant type of cells positively stained for MMP-9 in both groups. Once macrophage-like cells seemed to be the major source of MMP9, antibody against pan-CD68 epitope was used to correlate these findings. In agreement, MMP-9 and CD68(+) cells were distributed at the periphery and the central region of the granuloma in all experimental periods, however no staining was observed in cell contacting to material. Besides macrophages, the lysosomal glycoprotein epitope recognized by CD68 antibodies can be expressed by mast cell granules and sometimes by fibroblasts. Taken together, our results suggest that xenogenic HA promotes extracellular matrix remodeling through induction of MMP-9 activity and presence of CD68(+) cells.

The role of mast cells in non-ablative laser resurfacing with 1,320 nm neodymium:yttrium–aluminium–garnet laser

The aim of this study was to investigate the role of mast cells in mechanisms of collagen remodelling induced by non-ablative laser treatment. The dorsal skin of Kunming (KM) mice was exposed to 1,320 nm neodymium-yttrium-aluminium garnet (Nd:YAG) laser weekly for four consecutive weeks. Biopsies were taken 1 h after irradiation and 1 day, 7 days, 14 days, 30 days and 60 days after the first treatment. Skin samples were studied for mast cells, fibroblasts, and type I and III collagen, by toluidine blue, haematoxylin-eosin (HE) and immunohistochemical staining, respectively. The total number of mast cells in the skin of experimental group was significantly greater than that in the control at 1 h, 1 day, 21 days and 60 days after the first treatment (P < 0.05, respectively). At any of the time points studied, the number of degranulated mast cells in the experimental group was significantly higher than in the control (P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05, P < 0.05, respectively).The number of fibroblasts in the experimental group exhibited a significant increase in comparison with those in control skin at days 7, 21, 30 and 60 after irradiation (P < 0.05, P < 0.01, P < 0.01, P < 0.05, respectively). The amount of type I collagen was significantly higher than in the control from day 21 to day 60 (P < 0.05, P < 0.01, P < 0.01, respectively), and type III collagen showed a marked increase between day 7 and day 60, compared with the control (P < 0.01, P < 0.05, P < 0.01, P < 0.01, respectively). There was a significant positive correlation between the number of fibroblasts and granulated mast cells (r = 0.549, P < 0.01). The amount of type I and III collagen also showed significant positive correlations with the number of degranulated mast cells (r = 0.555, P < 0.01 and r = 0.579, P < 0.01, respectively). The results suggested that dermal mast cells might be involved in the inflammatory response, fibroblast proliferation and collagen remodelling induced by non-ablative laser treatment.

Molecular orbital studies of the mast cell zinc-histamine storage complex

A zinc-histamine-heparin complex is proposed as a storage form of histamine in rat mast cells. A ring nitrogen and the ethylamine nitrogen of two histamine molecules in a square planar arrangement about one divalent zinc ion may intercalate with a portion of the heparin molecule such that two sulfonic acid or carboxylate residues provide the fifth and sixth coordinating ligands above and below the plane of the zinc histamine complex. Semiempirical molecular orbital calculations employing an iterative extended Huckel method, Cusach's modification, indicate that there is little or no covalent bonding between the Zn atom and the donor nitrogen atoms. Thus the stability of the complex would appear to be owing to electrostatic interactions. These data correlate well with the demonstrated case of liberation of histamine from mast cell granules.

Tryptase-positive mast cells correlate with angiogenesis in early breast cancer patients

Literature data indicate that mast cells (MCs) are involved in tumor angiogenesis due to the release of several pro-angiogenetic factors among which tryptase, a serine protease stored in MCs granules, is one of the most active. However, no data are available concerning the role of MCs in angiogenesis in primary human breast cancer. In this study, we have evaluated the correlations between the number of MCs positive to tryptase (MCDPT), the area occupied by MCs positive to tryptase (MCAPT) and microvascular density (MVD) and endothelial area (EA) in a series of 88 primary T1-3, N0-2 M0 female breast cancer, by means of immunohistochemistry and image analysis methods. Data demonstrated a significant (r = from 0.78 to 0.89; p-value from 0.001 to 0.002 by Pearson's analysis respectively) correlation between MCDPT, MCAPT, MVD, EA to each other. No correlation concerning MCDPT, MCAPT, MVD, EA and the main clinicopathological features was found. Our results suggest that tryptase-positive MCs play a role in breast cancer angiogenesis. In this context several tryptase inhibitors such as gabexate mesilate and nafamostat mesilate might be evaluated in clinical trials as a new anti-angiogenetic approach.

AS-196: Mast Cell Granules Regulated Angiogenesis and Cell Survival in the Myocardial Infarction Rat Model

AS-196: Mast Cell Granules Regulated Angiogenesis and Cell Survival in the Myocardial Infarction Rat Model

Signalling mechanisms regulating the activation of human eosinophils by mast‐cell‐derived chymase: implications for mast cell–eosinophil interaction in allergic inflammation

Allergic diseases such as asthma and allergic dermatitis are associated with the degranulation of mast cells. Chymase, a mast-cell-specific protease, is the major component in mast cell granules that can induce eosinophil infiltration into inflammatory sites. We examined the immunopathological mechanisms for the activation of eosinophils by chymase in allergic inflammation. Cytokines were measured by cytometric bead array Flex Sets multiplex assay using flow cytometry and enzyme-linked immunosorbent assay. Adhesion molecules, migration and intracellular signalling pathways were assessed by flow cytometry, Boyden chamber assay and Western blot, respectively. Chymase suppressed the apoptosis of eosinophils and induce the release of the cytokine interleukin-6 (IL-6) and chemokines CXCL8, CCL2 and CXCL1 by eosinophils dose-dependently. It also up-regulated the surface expression of adhesion molecule CD18 and stimulated the chemokinetic migration of eosinophils. The expressions of adhesion molecules, cytokines and chemokines, and chemokinetic migration were differentially regulated by the activation of extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, Akt, Janus-activated kinase and nuclear factor-kappaB pathways. Chymase therefore plays a pivotal immunological role in the interaction between mast cells and eosinophils in allergic diseases such as allergic dermatitis by inducing adhesion molecule-mediated chemokinetic migration and inflammatory cytokines and chemokines of eosinophils, through multiple intracellular signalling molecules and transcription factor. Our results therefore provide a further biochemical basis for the pathogenesis of allergic inflammation consequent on the interaction between mast cells and eosinophils, and give insight for the development of new therapies.

Advances in mechanisms of asthma, allergy, and immunology in 2008

This review summarizes selected articles appearing in 2008 in the Journal. Articles chosen include those improving our understanding of mechanisms of allergic diseases by focusing on human basophil, mast cell, and eosinophil biology; IgE and its high-affinity receptor on various cells; novel properties of omalizumab; airways remodeling; and genetics. Articles from other journals have been included to supplement the topics presented.