87 research outputs found
IL-9 Induces VEGF Secretion from Human Mast Cells and IL-9/IL-9 Receptor Genes Are Overexpressed in Atopic Dermatitis
Interleukin 9 (IL-9) has been implicated in mast cell-related inflammatory diseases, such as asthma, where vascular endothelial growth factor (VEGF) is involved. Here we report that IL-9 (10–20 ng/ml) induces gene expression and secretion of VEGF from human LAD2. IL-9 does not induce mast cell degranulation or the release of other mediators (IL-1, IL-8, or TNF). VEGF production in response to IL-9 involves STAT-3 activation. The effect is inhibited (about 80%) by the STAT-3 inhibitor, Stattic. Gene-expression of IL-9 and IL-9 receptor is significantly increased in lesional skin areas of atopic dermatitis (AD) patients as compared to normal control skin, while serum IL-9 is not different from controls. These results imply that functional interactions between IL-9 and mast cells leading to VEGF release contribute to the initiation/propagation of the pathogenesis of AD, a skin inflammatory disease
Prostaglandin D2-supplemented “functional eicosanoid testing and typing” assay with peripheral blood leukocytes as a new tool in the diagnosis of systemic mast cell activation disease: an explorative diagnostic study
Background: Systemic mast cell activation disease (MCAD) is characterized by an enhanced release of mast cell-derived mediators, including eicosanoids, which induce a broad spectrum of clinical symptoms. Accordingly, the diagnostic algorithm of MCAD presupposes the proof of increased mast cell mediator release, but only a few mediators are currently established as routine laboratory parameters. We thus initiated an explorative study to evaluate in vitro typing of individual eicosanoid pattern of peripheral blood leukocytes (PBLs) as a new diagnostic tool in MCAD. Methods: Using the “functional eicosanoid testing and typing” (FET) assay, we investigated the balance (i.e. the complex pattern of formation, release and mutual interaction) of prostaglandin E2 (PGE2) and peptido-leukotrienes (pLT) release from PBLs of 22 MCAD patients and 20 healthy individuals. FET algorithms thereby consider both basal and arachidonic acid (AA)-, acetylsalicylic acid (ASA)-, and substance P (SP)-triggered release of PGE2 and pLT. The FET assay was further supplemented by analyzing prostaglandin D2 (PGD2), as mast cell-specific eicosanoid. Results: We observed marked PGE2-pLT imbalances for PBLs of MCAD patients, as indicated by a markedly enhanced mean FET value of 1.75 ± 0.356 (range: 1.14–2.36), compared to 0.53 ± 0.119 (range: 0.36-0.75) for healthy individuals. In addition, mean PGD2 release from PBLs of MCAD patients was significantly, 6.6-fold higher than from PBLs of healthy individuals (946 ± 302.2 pg/ml versus 142 ± 47.8 pg/ml; P < 0.001). In contrast to healthy individuals, PGD2 release from PBLs of MCAD patients was markedly triggered by SP (mean: 1896 ± 389.7 pg/ml; P < 0.001), whereas AA and ASA caused individually varying effects on both PGD2 and pLT release. Conclusions: The new in-vitro FET assay, supplemented with analysis of PGD2, demonstrated that the individual patterns of eicosanoid release from PBLs can unambiguously distinguish MCAD patients from healthy individuals. Notably, in our analyses, the FET value and both basal and triggered PGD2 levels were not significantly affected by MCAD-specific medication. Thus, this approach may serve as an in-vitro diagnostic tool to estimate mast cell activity and to support individualized therapeutic decision processes for patients suffering from MCAD
Secretion of mast cell inflammatory mediators is enhanced by CADM1-dependent adhesion to sensory neurons
Neuroimmune interactions are important in the pathophysiology of many chronic inflammatory diseases, particularly those associated with alterations in sensory processing and pain. Mast cells and sensory neuron nerve endings are found in areas of the body exposed to the external environment; both are specialized to sense potential damage by injury or pathogens and signal to the immune system and nervous system respectively, to elicit protective responses. Cell adhesion molecule 1 (CADM1), also known as SynCAM1, has previously been identified as an adhesion molecule which may couple mast cells to sensory neurons however, whether this molecule exerts a functional as well as structural role in neuroimmune cross-talk is unknown. Here we show, using a newly developed in vitro co-culture system consisting of murine bone marrow derived mast cells (BMMC) and adult sensory neurons isolated from dorsal root ganglions (DRG), that CADM1 is expressed in mast cells and adult sensory neurons and mediates strong adhesion between the two cell types. Non-neuronal cells in the DRG cultures did not express CADM1, and mast cells did not adhere to them. The interaction of BMMCs with sensory neurons was found to induce mast cell degranulation and IL-6 secretion and to enhance responses to antigen stimulation and activation of FcεRI receptors. Secretion of TNFα in contrast was not affected, nor was secretion evoked by compound 48/80. Co-cultures of BMMCs with HEK 293 cells, which also express CADM1, while also leading to adhesion did not replicate the effects of sensory neurons on mast cells, indicative of a neuron-specific interaction. Application of a CADM1 blocking peptide or knockdown of CADM1 in BMMCs significantly decreased BMMC attachment to sensory neurites and abolished the enhanced secretory responses of mast cells. In conclusion, CADM1 is necessary and sufficient to drive mast cell-sensory neuron adhesion and promote the development of a microenvironment in which neurons enhance mast cell responsiveness to antigen; this interaction could explain why the incidence of painful neuroinflammatory disorders such as irritable bowel syndrome (IBS) are increased in atopic patients
Mast cells squeeze the heart and stretch the gird: Their role in atherosclerosis and obesity
Mast cells are crucial for the development of allergic and anaphylactic reactions, but they are also involved in acquired and innate immunity. Increasing evidence now implicates mast cells in inflammatory diseases through activation by non-allergic triggers such as neuropeptides and cytokines. This review discusses how mast cells contribute to the inflammatory processes associated with coronary artery disease and obesity. Animal models indicate that mast cells, through the secretion of various vasoactive mediators, cytokines and proteinases, contribute to coronary plaque progression and destabilization, as well as to diet-induced obesity and diabetes. Understanding how mast cells participate in these inflammatory processes could help in the development of unique inhibitors with novel therapeutic applications for these diseases, which constitute the greatest current threat to global human health and welfare. © 2011 Elsevier Ltd. All rights reserved
Do mast cells link obesity and asthma?
Asthma is a chronic inflammatory disease of the lungs. Both the number
of cases and severity of asthma have been increasing without a clear
explanation. Recent evidence suggests that obesity, which has also been
increasing alarmingly, may worsen or precipitate asthma, but there is
little evidence of how obesity may contribute to lung inflammation. We
propose that mast cells are involved in both asthma and obesity by being
the target and source of adipocytokines, alarmins such as interleukin-9
(IL-9) and interleukin-33 (IL-33), and stress molecules including
corticotropin-releasing hormone (CRH) and neurotensin (NT), secreted in
response to the metabolic burden. In particular, CRH and NT have
synergistic effects on mast cell secretion of vascular endothelial
growth factor (VEGF). IL-33 augments VEGF release induced by substance P
(SP) and tumor necrosis factor (TNF) release induced by NT. Both IL-9
and IL-33 also promote lung mast cell infiltration and augment allergic
inflammation. These molecules are also expressed in human mast cells
leading to autocrine effects. Obese patients are also less sensitive to
glucocorticoids and bronchodilators. Development of effective mast cell
inhibitors may be a novel approach for the management of both asthma and
obesity. Certain flavonoid combinations may be a promising new treatment
approach
Rupatadine inhibits inflammatory mediator release from human laboratory of allergic diseases 2 cultured mast cells stimulated by platelet-activating factor
Background: Mast cells are involved in allergy and inflammation by the
secretion of multiple mediators, including histamine, cytokines, and
platelet-activating factor (PAF), in response to different triggers,
including emotional stress. PAF has been associated with allergic
inflammation, but there are no clinically available PAF inhibitors.
Objective: To investigate whether PAF could stimulate human mast cell
mediator release and whether rupatadine (RUP), a dual histamine-1 and
PAF receptor antagonist, could inhibit the effect of PAF on human mast
cells.
Methods: Laboratory of allergic diseases 2 cultured mast cells were
stimulated with PAF (0.001, 0.01, and 0.1 mu mol/L) and substance P (1
mu mol/L) with or without pretreatment with RUP (2.5 and 25 mu mol/L),
which was added 10 minutes before stimulation. Release of
beta-hexosaminidase was measured in supernatant fluid by
spectrophotoscopy, and histamine, interleukin-8, and tumor necrosis
factor were measured by enzyme-linked immunosorbent assay.
Results: PAF stimulated a statistically significant release of
histamine, interleukin-8, and tumor necrosis factor (0.001-0.1 mu mol/L)
that was comparable to that stimulated by substance P. Pretreatment with
RUP (25 mu mol/L) for 10 minutes inhibited this effect. In contrast,
pretreatment of laboratory of allergic diseases 2 cells with
diphenhydramine (25 mu mol/L) did not inhibit mediator release,
suggesting that the effect of RUP was not due to its antihistaminic
effect.
Conclusion: PAF stimulates human mast cell release of proinflammatory
mediators that is inhibited by RUP. This action endows RUP with
additional properties in treating allergic inflammation. (C) 2013
American College of Allergy, Asthma & Immunology. Published by Elsevier
Inc. All rights reserved
Stimulated Human Mast Cells Secrete Mitochondrial Components That Have Autocrine and Paracrine Inflammatory Actions
<div><p>Mast cells are hematopoietically-derived tissue immune cells that participate in acquired and innate immunity, as well as in inflammation through release of many chemokines and cytokines, especially in response to the pro-inflammatory peptide substance P (SP). Inflammation is critical in the pathogenesis of many diseases, but the trigger(s) is often unknown. We investigated if mast cell stimulation leads to secretion of mitochondrial components and whether these could elicit autocrine and/or paracrine inflammatory effects. Here we show that human LAD2 mast cells stimulated by IgE/anti-IgE or by the SP led to secretion of mitochondrial particles, mitochondrial (mt) mtDNA and ATP without cell death. Mitochondria purified fromLAD2 cells and, when mitochondria added to mast cells trigger degranulation and release of histamine, PGD<sub>2</sub>, IL-8, TNF, and IL-1β. This stimulatory effect is partially inhibited by an ATP receptor antagonist and by DNAse. These results suggest that the mitochondrial protein fraction may also contribute. Purified mitochondria also stimulate IL-8 and vascular endothelial growth factor (VEGF) release from cultured human keratinocytes, and VEGF release from primary human microvascular endothelial cells. In order to investigate if mitochondrial components could be secreted <em>in vivo</em>, we injected rats intraperiotoneally (ip) with compound 48/80, which mimicks the action of SP. Peritoneal mast cells degranulated and mitochondrial particles were documented by transimission electron microscopy outside the cells. We also wished to investigate if mitochondrial components secreted locally could reach the systemic circulation. Administration ip of mtDNA isolated from LAD2 cells in rats was detected in their serum within 4 hr, indicating that extravascular mtDNA could enter the systemic circulation. Secretion of mitochondrial components from stimulated live mast cells may act as “autopathogens” contributing to the pathogenesis of inflammatory diseases and may be used as targets for novel treatments.</p> </div
Mast Cells in Allergic and Inflammatory Diseases
Mast cells are important in the development of allergic and anaphylactic
reactions, but also in acquired and innate immunity. There is also
increasing evidence that mast cells participate in inflammatory
diseases, where they can be activated by non-allergic triggers, such as
neuropeptides and cytokines, often having synergistic effects as in the
case of substance P (SP) and IL-33. Secretion of vasoactive mediators,
cytokines and proteinases contribute to the development of coronary
artery disease (CAD), as well as to diet-induced obesity and the
metabolic syndrome. Mast cells may be able to orchestrate such different
biological processes through their ability to release pro-inflammatory
mediators selectively without the degranulation typical of allergic
reactions. Recent evidence suggests that mitochondrial uncoupling
protein 2 (UCP2) and mitochondrial translocation regulate mast cell
degranulation, but not selective mediator release. Better understanding
of these two processes and how mast cells exert both immunostimulatory
and immunosuppressive actions could lead to the development of
inhibitors of release of specific mediators with novel therapeutic
applications
Mast cell degranulation results in extracellular mitochondrial particles translocation.
<p>hCBMCs were stained with MitoTracker Deep Red (20 nM) for 20 min and LysoTracker DND green (50 nM) for 30 min, then seeded in glass bottom culture dishes and observed under Leica TCS SP2 Confocal microscope. Mitochondrial distribution was observed in resting (upper panels) and degranulated (bottom panels) mast cells stimulated as shown. The left panels depict secretory granules in green and the middle panels represent mitochondria fluorescence in red. The right panels represent images merged from the two previous panels.</p
IL-9 Induces VEGF Secretion from Human Mast Cells and IL-9/IL-9 Receptor Genes Are Overexpressed in Atopic Dermatitis
Interleukin 9 (IL-9) has been implicated in mast cell-related
inflammatory diseases, such as asthma, where vascular endothelial growth
factor (VEGF) is involved. Here we report that IL-9 (10-20 ng/ml)
induces gene expression and secretion of VEGF from human LAD2. IL-9 does
not induce mast cell degranulation or the release of other mediators
(IL-1, IL-8, or TNF). VEGF production in response to IL-9 involves
STAT-3 activation. The effect is inhibited (about 80%) by the STAT-3
inhibitor, Stattic. Gene-expression of IL-9 and IL-9 receptor is
significantly increased in lesional skin areas of atopic dermatitis (AD)
patients as compared to normal control skin, while serum IL-9 is not
different from controls. These results imply that functional
interactions between IL-9 and mast cells leading to VEGF release
contribute to the initiation/propagation of the pathogenesis of AD, a
skin inflammatory disease
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