Changes in mast cells and in permeability of mesenteric microvessels under the effect of immobilization and electrostimulation

It was shown that a reduction in the amount of mast cells in the mesentery and an increase in their degranulation was accompanied by an increase in vascular permeability of rat mesentery. It is supposed that immobilization and electrostimulation causing degranulation of mast cells prompted histamine and serotonin release from them, thus increasing the permeability of the venular portion of the microvascular bed. Prophylactic use of esculamin preparation with P-vitaminic activity decreased mast cell degranulation, which apparently prolonged the release of histamine and serotonin from them and normalized vascular permeability

Effect of low-intensity pulsed ultrasound on mast cell degranulation and fibroblast expression on type 2 diabetes mellitus rats wound healing process

Impaired wound healing is one of the Diabetes mellitus complications. Low-intensity Pulsed Ultrasound (LIPUS) therapy may accelerate the impaired wound healing. The use of LIPUS therapy in the early inflammatory phase can induce mast cell degranulation, and in the proliferative phase it can increase collagen synthesis by fibroblasts. The purpose of this study was to determine the effects of LIPUS therapy on mast cell degranulation and fibroblastexpression in the healing process of punch biopsy wound in rats with type 2 diabetes mellitus. Twenty-four Sprague dawley (n=24) were designed into type 2 diabetes mellitus by injecting Nicotinamide and Streptozotocin, then divided into six groups: diabetes mellitus without LIPUS (DM3, DM7, DM14) and diabetes mellitus with LIPUS (DML3, DML7, DML14), 4 each, and punch biopsy wounds were made on the dorsal skin. The DML group received LIPUS therapy in the wound area (frequency 3 MHz, intensity 0.5 W/cm2, duty cycle 20%, duration 3 minutes every day for 3 days (DML3), 7 days (DML7), and 14 days (DML14). The wounded tissue area was stained with toluidine blue to observe mast cell degranulation and immunohistochemical type HSP-47 to observe fibroblast expression. Two-Way ANOVA and Post Hoc LSD tests were used to determine the differences in mast cell degranulation and fibroblast expression. The results showed that mast cell degranulation and fibroblast expression in the DML group were higher than in the DM group (table 1). Pearson test showed a correlation between mast cell degranulation and fibroblast expression (p=0.00; r= 0.839). LIPUS therapy increases mast cell degranulation and fibroblast expression in type 2 diabetes mellitus rat model. The higher the mast cell degranulation, the higher fibroblast expressions

Choroidal mast cells in retinal pathology: a potential target for intervention.

Mast cells are important in the initiation of ocular inflammation, but the consequences of mast cell degranulation on ocular pathology remain uncharacterized. We induced mast cell degranulation by local subconjunctival injection of compound 48/80. Initial degranulation of mast cells was observed in the choroid 15 minutes after the injection and increased up to 3 hours after injection. Clinical signs of anterior segment inflammation paralleled mast cell degranulation. With the use of optical coherence tomography, dilation of choroidal vessels and serous retinal detachments (SRDs) were observed and confirmed by histology. Subconjunctival injection of disodium cromoglycate significantly reduced the rate of SRDs, demonstrating the involvement of mast cell degranulation in posterior segment disorders. The infiltration of polymorphonuclear and macrophage cells was associated with increased ocular media concentrations of tumor necrosis factor-α, CXCL1, IL-6, IL-5, chemokine ligand 2, and IL-1β. Analysis of the amounts of vascular endothelial growth factor and IL-18 showed an opposite evolution of vascular endothelial growth factor compared with IL-18 concentrations, suggesting that they regulate each other's production. These findings suggest that the local degranulation of ocular mast cells provoked acute ocular inflammation, dilation, increased vascular permeability of choroidal vessels, and SRDs. The involvement of mast cells in retinal diseases should be further investigated. The pharmacologic inhibition of mast cell degranulation may be a potential target for intervention

HCMV pUL135 remodels the actin cytoskeleton to impair immune recognition of infected cells

Immune evasion genes help human cytomegalovirus (HCMV) establish lifelong persistence. Without immune pressure, laboratory-adapted HCMV strains have undergone genetic alterations. Among these, the deletion of the UL/b’ domain is associated with loss of virulence. In a screen of UL/b’, we identified pUL135 as a protein responsible for the characteristic cytopathic effect of clinical HCMV strains that also protected from natural killer (NK) and T cell attack. pUL135 interacted directly with abl interactor 1 (ABI1) and ABI2 to recruit the WAVE2 regulatory complex to the plasma membrane, remodel the actin cytoskeleton and dramatically reduce the efficiency of immune synapse (IS) formation. An intimate association between F-actin filaments in target cells and the IS was dispelled by pUL135 expression. Thus, F-actin in target cells plays a critical role in synaptogenesis, and this can be exploited by pathogens to protect against cytotoxic immune effector cells. An independent interaction between pUL135 and talin disrupted cell contacts with the extracellular matrix

Mast cell subsets and their functional modulation by the Acanthocheilonema viteae product ES-62

ES-62, an immunomodulator secreted by filarial nematodes, exhibits therapeutic potential in mouse models of allergic inflammation, at least in part by inducing the desensitisation of Fc휀RI-mediated mast cell responses. However, in addition to their pathogenic roles in allergic and autoimmune diseases, mast cells are important in fighting infection, wound healing, and resolving inflammation, reflecting that mast cells exhibit a phenotypic and functional plasticity. We have therefore characterised the differential functional responses to antigen (via Fc휀RI) and LPS and their modulation by ES-62 of the mature peritoneal-derived mast cells (PDMC; serosal) and those of the connective tissue-like mast cells (CTMC) and themucosal-likemast cells derived from bone marrow progenitors (BMMC) as a first step to produce disease tissue-targeted therapeutics based on ES-62 action. All three mast cell populations were rendered hyporesponsive by ES-62 and whilst the mechanisms underlying such desensitisation have not been fully delineated, they reflect a downregulation of calcium and PKC훼 signalling. ES-62 also downregulatedMyD88 and PKC훿 in mucosal-type BMMC but not PDMC, the additional signals targeted in mucosal-type BMMC likely reflecting that these cells respond to antigen and LPS by degranulation and cytokine secretion whereas PDMC predominantly respond in a degranulationbased manner

Stimulation of TRPV1 by green laser light

Low-level laser irradiation of visible light had been introduced as a medical treatment already more than 40 years ago, but its medical application still remains controversial. Laser stimulation of acupuncture points has also been introduced, and mast-cells degranulation has been suggested. Activation of TRPV ion channels may be involved in the degranulation. Here, we investigated whether TRPV1 could serve as candidate for laser-induced mast cell activation. Activation of TRPV1 by capsaicin resulted in degranulation. To investigate the effect of laser irradiation on TRPV1, we used the Xenopus oocyte as expression and model system. We show that TRPV1 can functionally be expressed in the oocyte by (a) activation by capsaicin (K 1/2 = 1.1 μM), (b) activation by temperatures exceeding 42°C, (c) activation by reduced pH (from 7.4 to 6.2), and (d) inhibition by ruthenium red. Red (637 nm) as well as blue (406 nm) light neither affected membrane currents in oocytes nor did it modulate capsaicin-induced current. In contrast, green laser light (532 nm) produced power-dependent activation of TRPV1. In conclusion, we could show that green light is effective at the cellular level to activate TRPV1. To which extend green light is of medical relevance needs further investigation

CD155 on HIV-infected cells is not modulated by HIV-1 Vpu and Nef but synergizes with NKG2D ligands to trigger NK cell lysis of autologous primary HIV-infected cells

Activation of primary CD4(+) T cells induces the CD155, but not the CD112 ligands for the natural killer (NK) cell activation receptor (aNKR) CD226 [DNAX accessory molecule-1 (DNAM-1)]. We hypothesize that HIV productively infects activated CD4(+) T cells and makes itself vulnerable to NK cell-mediated lysis when CD155 on infected T cells engages DNAM-1. The primary objective of this study is to determine whether CD155 alone or together with NKG2D ligands triggers autologous NK cell lysis of HIV-infected T cells and whether HIV modulates CD155. To determine whether HIV modulates this activation ligand, we infected “activated” CD4(+) T cells with HIV in the absence or presence of Nef and/or Vpu and determined by flow cytometry whether they modulated CD155. To determine if CD155 alone, or together with NKG2D ligands, triggered NK cell lysis of autologous HIV-infected T cells, we treated purified NK cells with DNAM-1 and/or NKG2D blocking antibodies before the addition of purified autologous HIV-infected cells in cytolytic assays. Finally, we determined whether DNAM-1 works together with NKG2D as an NK cell coactivation receptor (caNKR) or whether they work independently as aNKRs to induce an NK cell lytic response. We demonstrate that HIV and specifically Nef and/or Vpu do not modulate CD155 on infected primary T cells; and both CD155 and NKG2D ligands synergize as aNKRs to trigger NK cell lysis of the infected cell

Tissue eosinophilia and eosinophil degranulation in Riedel's invasive fibrous thyroiditis.

The etiology of Riedel's invasive fibrous thyroiditis (IFT) has remained obscure. This rare disorder has been confused in the past with the more common fibrous variant of Hashimoto's disease. The typical histological features of IFT, in particular the presence of an invasive fibrosclerotic process in conjunction with a prominent chronic inflammatory infiltrate, suggest that the release of fibrogenic cytokines and other factors from these cellular infiltrates may play an important role in the pathogenesis of this condition. Our observations in routinely processed tissue sections obtained from patients with documented IFT of striking tissue eosinophilia led us to hypothesize that eosinophils and their products may play a role in the evolution of this disease. Immunofluorescence staining with affinity-purified polyclonal rabbit antibody directed against human eosinophil granule major basic protein revealed marked tissue eosinophilia and abundant extracellular deposition of major basic protein in all specimens from 16 patients with IFT. By contrast, only occasional eosinophils and no extracellular major basic protein were detected in control thyroid tissues obtained from patients with multinodular goiter, Graves' disease, Hashimoto's disease, and normal thyroid tissue. The presence of marked eosinophil infiltration and extracellular major basic protein deposition in IFT and other associated fibrosclerotic conditions suggests a role for eosinophils and their products in propagating the fibrogenesis seen in IFT

Insights on cytotoxic cells of the colonial ascidian Botryllus schlosseri

Morula cells (MCs) represent the most abundant circulating hemocyte of the compound ascidian Botryllus schlosseri. They are cytotoxic cells involved in the rejection reaction between contacting, genetically incompatible colonies. Upon the recognition of foreign substances, they degranulate and release their content, which contribute to the cell death along the contact borders. A major role in MC-related cytotoxicity is exerted by the enzyme phenoloxidase (PO) that converts polyphenol substrata to quinones which, then, polymerize to form melanins. During this reaction, reactive oxygen species are formed which are the cause of MC-related cytotoxicity. Here, we carried out new analyses to investigate further the nature of MC content and its role in cytotoxicity. Results confirm that PO is located inside MC vacuoles together with arylsulfatase, iron and polyphenols/quinones, the latter probably representing ready-to-use cytotoxic molecules, deriving from the oxidation of DOPA-containing proteins. In addition, small DOPA-containing peptides, called tunichromes, are also present inside MCs. MC degranulation and PO-mediated cytotoxicity are prevented by secretion inhibitors and by H89 and calphostin C. The observation that PO activity is always detectable in MCs in the absence of protease treatment, and its inhibition by sulfites and sulfates, suggest a non-classical pathway of PO modulation in botryllid ascidians