Modulation Of Mast Cell Activation Research Articles

Antidepressant-like Effects of Cannabis sativa L. Extract in an Lipopolysaccharide Model: Modulation of Mast Cell Activation in Deep Cervical Lymph Nodes and Dura Mater.

Lipopolysaccharide (LPS)-induced neuroinflammation is a well-established model for studying depression-like behavior, driven by pro-inflammatory cytokines such as TNF-α and IL-1β. Mast cells (MCs) contribute to neuroinflammation by releasing mediators that exacerbate depressive-like symptoms. This study evaluates the antidepressant-like and anti-inflammatory effects of Cannabis sativa L. inflorescence extract (CSL) in an LPS-induced neuroinflammation model. Male C57BL/6 mice were intraperitoneally injected with CSL at doses of 10, 20, and 30 mg/kg, 30 min prior to LPS (0.83 mg/kg) administration. Depressive behaviors were assessed using the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST). The neutrophil-to-lymphocyte ratio (NLR) was measured to assess systemic inflammation. Cytokine levels in the prefrontal cortex (PFC) were measured, and mast cell degranulation in the lymph nodes and dura mater was analyzed histologically (approval number: WKU24-64). CSL significantly improved depressive-like behaviors and decreased the NLR, indicating reduced systemic inflammation. CSL also significantly reduced TNF-α and IL-1β levels in the PFC. Furthermore, CSL inhibited MC degranulation in the deep cervical lymph nodes and dura mater, with the strongest effects observed at 30 mg/kg. CSL demonstrated antidepressant-like and anti-inflammatory effects in an LPS-induced neuroinflammation model, likely through the modulation of cytokine expression and mast cell activity. These results suggest the potential of CSL as a therapeutic option for treating inflammation-related depression.

Palmitoylethanolamide Reduces Granuloma-Induced Hyperalgesia by Modulation of Mast Cell Activation in Rats

The aim of this study was to obtain evidences of a possible analgesic role for palmitoylethanolamide (PEA) in chronic granulomatous inflammation sustained by mast cell (MC) activation in rats at 96 hours. PEA (200-400-800 μg/mL), locally administered at time 0, reduced in a concentration-dependent manner the expression and release of NGF in comparison with saline-treated controls. PEA prevented nerve formation and sprouting, as shown by histological analysis, reduced mechanical allodynia, evaluated by Von Frey filaments, and inhibited dorsal root ganglia activation. These results were supported by the evidence that MCs in granuloma were mainly degranulated and closely localized near nerve fibres and PEA significantly reduced MC degranulation and nerves fibre formation. These findings are the first evidence that PEA, by the modulation of MC activation, controls pain perception in an animal model of chronic inflammation, suggesting its potential use for the treatment of all those painful conditions in which MC activation is an initial key step.

Protein Tyrosine Phosphatase ε is a Negative Regulator of FcεRI‐mediated Mast Cell Responses

Modulation of mast-cell activation may provide novel ways to control allergic diseases. Here, we show that protein tyrosine phosphatase epsilon (PTPepsilon; Ptpre) plays key regulatory roles during mast-cell activation mediated by the high-affinity IgE receptor (FcepsilonRI). Bone marrow-derived mast cells (BMMC) from Ptpre(-/-) mice exhibited enhanced FcepsilonRI-induced Ca(2+) mobilization and mitogen-activated protein kinase (MAPK) (JNK and p38) activation, and showed corresponding enhancement of evoked degranulation and cytokine production, but not leukotriene production. Examination of proteins linking tyrosine kinase activation and Ca(2+) mobilization revealed that the absence of PTPepsilon leads to increased phosphorylation of the linker for activation of T cells and SH2 domain-containing leucocyte phosphoproteins of 76 kDa, but not Grb2-associated binder-2 (Gab2). Because Gab2 is considered to be situated downstream of Fyn kinase, we reasoned that Fyn may not be a target of PTPepsilon. In the event, Syk but not Lyn was hyperphosphorylated in PTPepsilon-deficient BMMC. Thus, PTPepsilon most likely exerts its effects at the level of Syk, inhibiting downstream events including phosphorylation of SLP-76 and linker of activated T cells and mobilization of Ca(2+). Consistent with the in vitro data, antigen- and IgE-mediated passive systemic anaphylactic reactions were augmented in Ptpre(-/-) mice. Given that the number of mast cells is unchanged in these mice, this observation most likely reflects alterations of mast cell-autonomous signalling events. These data suggest that PTPepsilon negatively regulates FcepsilonRI-mediated signalling pathways and thus constitutes a novel target for ameliorating allergic conditions.

Fluctuation of annexin-A1 positive mast cells in chronic granulomatous inflammation

We have applied here a model of chronic granulomatous inflammation to study the profile of mast cell activation and their expression of annexin-A1 in the nodular lesion. Granulomatous inflammation was induced by injection of croton oil and Freund's complete adjuvant (CO/FCA) into the dorsal air-pouches of mice. Skin tissue samples were collected from control group (24 h time-point; i. e. before disease development) and 7, 14, 21, 28 and 42 days post-CO/FCA treatment. Histopathological analyses revealed an on-going inflammation characterized by an increased number of activated mast cells at sites of the chronic inflammatory reaction in all experimental groups. Immunohistochemical analysis showed skin mast cells highly immunoreactive for annexin-A1, both at an initial (day 7) and a delayed (day 28) phase of the inflammatory reaction. The observed time-dependent modulation of mast cell activation, during the granulomatous injury, indicates that multiple pathways centred on annexin-A1 might become activated at different stages of this chronic inflammatory response, including the delayed and pro-resolving phase.

Effects of the Schisandra Fructus Water Extract on Cytokine Release from a Human Mast Cell Line

Schisandra fructus has been used for treatment of cough and thirst in Korea. However, its therapeutic mechanisms remain largely unclear. To investigate the biological effect of Schisandra fructus water extract (SFWE), we examined the effect of SFWE on the phorbol 12-myristate 13-acetate (PMA) and calcium ionophore A23187-induced pro-inflammatory cytokine secretion in the human mast cell line HMC-1. HMC-1 cells were stimulated with PMA plus A23187 in the presence or absence of SFWE. Tumor necrosis factor (TNF)-alpha, interleukin 6 (IL-6), and granulocyte-macrophage colony-stimulating factor (GM-CSF) productions were measured by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. Inhibitory IkappaB/nuclear factor-kappaB (NF-kappaB) expression was assessed by western blot. SFWE suppressed PMA plus A23187-induced TNF-alpha, IL-6, and GM-CSF production in dose-dependent manners. Furthermore, SFWE inhibited IkappaB degradation and NF-kappaB nuclear translocation. These results suggest that SFWE inhibits the secretion of pro-inflammatory cytokines in HMC-1 cells through blockade of IkappaB degradation and NF-kappaB activation. Taken together, these findings may help elucidate the mechanism of action of this medicine in the modulation of mast cell activation in inflammatory conditions.

Absence of platelet endothelial cell adhesion molecule-1 (CD31) leads to increased severity of local and systemic IgE-mediated anaphylaxis and modulation of mast cell activation.

Platelet endothelial cell adhesion molecule-1 (PECAM-1) is a newly assigned member of the Ig-immunoreceptor tyrosine-based inhibitory motif superfamily, and its functional role is suggested to be an inhibitory receptor that modulates immunoreceptor tyrosine-based activation motif-dependent signaling cascades. In this study, we hypothesized that PECAM-1 plays an essential in vivo role as a counterregulator of immediate hypersensitivity reactions. We found that PECAM-1 was highly expressed on the surface of immature bone marrow mast cells and at a lower density on mature peritoneal mast cells. Examination of skin biopsies from PECAM-1(+/+) and PECAM-1(-/-) mice revealed that absence of PECAM-1 did not affect mast cell development or the capacity of mast cells to populate tissues. To examine whether the absence of PECAM-1 would influence immediate hypersensitivity reactions, PECAM-1(+/+) and PECAM-1(-/-) mice were presensitized with anti-DNP mouse IgE and then challenged 20 h later with DNP-BSA or PBS. PECAM-1(-/-) mice exhibited elevated serum histamine concentrations after Ag stimulation compared with PECAM-1(+/+) mice, indicating an increased severity of systemic IgE-mediated anaphylaxis. PECAM-1(-/-) mice have increased sensitivity to local cutaneous IgE-dependent anaphylaxis compared with PECAM-1(+/+) mice, as assessed by greater tissue swelling of their ears and mast cell degranulation in situ. PECAM-1(-/-) bone marrow mast cells showed enhanced dense granule serotonin release after Fc epsilon RI cross-linking in vitro. These results suggest that PECAM-1 acts as a counterregulator in allergic disease susceptibility and severity and negatively modulates mast cell activation.

Time course of changes in adenosine 5′-monophosphate airway responsiveness with inhaled heparin in allergic asthma

Background: Recent studies have shown that inhaled heparin exerts a protective effect against various bronchoconstrictor stimuli in asthma, possible through an inhibition of mast cell activation. Objective: Because adenosine 5′-monophosphate (AMP) elicits bronchoconstriction by augmenting mast cell mediator release, we have investigated the effect of inhaled heparin (15,000 units USP/ml, 4 ml) on the bronchoconstrictor response to this agonist and to methacholine in a randomized, double-blind, placebo-controlled study of 10 subjects with asthma. We also carried out a separate randomized, double-blind study in seven additional volunteers with asthma to examine in more detail the time-course of change in bronchial reactivity to inhaled AMP after treatment with nebulized heparin. Results: Inhaled heparin significantly increased the provocative concentration of AMP causing a 20% decrease in forced expiratory volume in 1 second (PC 20FEV 1-AMP) from the postplacebo treatment value of 22.3 mg/ml (range, 5.7 to 68.9 mg/ml) to 48.1 mg/ml (range, 5.1 196.8 mg/ml) ( p < 0.01). When compared with placebo, inhaled heparin failed to alter the airway responsiveness to methacholine; the mean (range) PC 20 methacholine values were 1.00 mg/ml (0.44 to 4.76 mg/ml) and 1.08 mg/ml (0.46 to 5.08 mg/ml), respectively. After placebo administration, the PC 20 AMP values at 15, 60, and 180 minutes did not differ significantly from each other; their geometric mean (range) values were 26.1 mg/ml (5.9 to 85.8 mg/ml), 26.6 mg/ml (6.3 to 87.8 mg/ml), and 24.9 mg/ml (5.2 to 80.2 mg/ml), respectively. When compared with placebo, the PC 20 values for AMP after administration of inhaled heparin were significantly increased up to 57.3 mg/ml (14.7 to 176.0 mg/ml) and to 52.7 mg/ml (13.9 to 90.8 mg/ml) at 15 minutes and 60 minutes, respectively. At 180 minutes, inhaled heparin failed to affect AMP airway responsiveness; the PC 20 AMP was not significantly different from that of placebo, with a value of 30.6 mg/ml (4.8 to 93.3 mg/ml). Conclusion: Heparin administered by inhalation is effective in attenuating the airway response to AMP but not to methacholine. The time course of change in bronchial reactivity to AMP has a peak effect at 15 minutes and lasts up to 60 minutes. It is possible that the mechanism(s) underlying the protective effects of inhaled heparin in asthma may be related to an inhibitory modulation of mast cell activation. (J Allergy Clin Immunol 1997;99:338-44.)