Pentacyclic triterpenoids, including ursolic acid (UA), are bioactive compounds with multiple biological activities involving anti-inflammatory effects. However, the mode of their action on mast cells, key players in the early stages of allergic inflammation, and underlying molecular mechanisms remain enigmatic. To better understand the effect of UA on mast cell signaling, here we examined the consequences of short-term treatment of mouse bone marrow-derived mast cells with UA. Using IgE-sensitized and antigen- or thapsigargin-activated cells, we found that 15 min exposure to UA inhibited high affinity IgE receptor (FcεRI)-mediated degranulation, calcium response, and extracellular calcium uptake. We also found that UA inhibited migration of mouse bone marrow-derived mast cells toward antigen but not toward prostaglandin E2 and stem cell factor. Compared to control antigen-activated cells, UA enhanced the production of tumor necrosis factor-α at the mRNA and protein levels. However, secretion of this cytokine was inhibited. Further analysis showed that UA enhanced tyrosine phosphorylation of the SYK kinase and several other proteins involved in the early stages of FcεRI signaling, even in the absence of antigen activation, but inhibited or reduced their further phosphorylation at later stages. In addition, we show that UA induced changes in the properties of detergent-resistant plasma membrane microdomains and reduced antibody-mediated clustering of the FcεRI and glycosylphosphatidylinositol-anchored protein Thy-1. Finally, UA inhibited mobility of the FcεRI and cholesterol. These combined data suggest that UA exerts its effects, at least in part, via lipid-centric plasma membrane perturbations, hence affecting the functions of the FcεRI signalosome.

• Klíčová slova
• immunoglobulin E, lipid raft, mast cell, plasma membrane, signal transduction, tumor necrosis factor, tyrosine kinase,
• MeSH
• antigeny metabolismus   MeSH
• degranulace buněk MeSH
• kyselina ursolová MeSH
• lipidy farmakologie   MeSH
• mastocyty metabolismus   MeSH
• myši MeSH
• receptory IgE * metabolismus   MeSH
• triterpeny * farmakologie   metabolismus   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny MeSH
• lipidy MeSH
• receptory IgE * MeSH
• triterpeny * MeSH
• vápník MeSH

Protein 4.1R, a member of the 4.1 family, functions as a bridge between cytoskeletal and plasma membrane proteins. It is expressed in T cells, where it binds to a linker for activation of T cell (LAT) family member 1 and inhibits its phosphorylation and downstream signaling events after T cell receptor triggering. The role of the 4.1R protein in cell activation through other immunoreceptors is not known. In this study, we used 4.1R-deficient (4.1R-KO) and 4.1R wild-type (WT) mice and explored the role of the 4.1R protein in the high-affinity IgE receptor (FcεRI) signaling in mast cells. We found that bone marrow mast cells (BMMCs) derived from 4.1R-KO mice showed normal growth in vitro and expressed FcεRI and c-KIT at levels comparable to WT cells. However, 4.1R-KO cells exhibited reduced antigen-induced degranulation, calcium response, and secretion of tumor necrosis factor-α. Chemotaxis toward antigen and stem cell factor (SCF) and spreading on fibronectin were also reduced in 4.1R-KO BMMCs, whereas prostaglandin E2-mediated chemotaxis was not affected. Antibody-induced aggregation of tetraspanin CD9 inhibited chemotaxis toward antigen in WT but not 4.1R-KO BMMCs, implying a CD9-4.1R protein cross-talk. Further studies documented that in the absence of 4.1R, antigen-mediated phosphorylation of FcεRI β and γ subunits was not affected, but phosphorylation of SYK and subsequent signaling events such as phosphorylation of LAT1, phospholipase Cγ1, phosphatases (SHP1 and SHIP), MAP family kinases (p38, ERK, JNK), STAT5, CBL, and mTOR were reduced. Immunoprecipitation studies showed the presence of both LAT1 and LAT2 (LAT, family member 2) in 4.1R immunocomplexes. The positive regulatory role of 4.1R protein in FcεRI-triggered activation was supported by in vivo experiments in which 4.1R-KO mice showed the normal presence of mast cells in the ears and peritoneum, but exhibited impaired passive cutaneous anaphylaxis. The combined data indicate that the 4.1R protein functions as a positive regulator in the early activation events after FcεRI triggering in mast cells.

• Klíčová slova
• 4.1R protein, chemotaxis, degranulation, mast cell, passive cutaneous anaphylaxis,
• MeSH
• chemotaxe imunologie   MeSH
• degranulace buněk imunologie   MeSH
• mastocyty imunologie   metabolismus   MeSH
• mikrofilamentové proteiny imunologie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• pasivní kožní anafylaxe imunologie   MeSH
• receptory IgE imunologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• Epb41 protein, mouse MeSH Prohlížeč
• mikrofilamentové proteiny MeSH
• receptory IgE MeSH

C-terminal Src kinase (CSK) is a major negative regulator of Src family tyrosine kinases (SFKs) that play critical roles in immunoreceptor signaling. CSK is brought in contiguity to the plasma membrane-bound SFKs via binding to transmembrane adaptor PAG, also known as CSK-binding protein. The recent finding that PAG can function as a positive regulator of the high-affinity IgE receptor (FcεRI)-mediated mast cell signaling suggested that PAG and CSK have some non-overlapping regulatory functions in mast cell activation. To determine the regulatory roles of CSK in FcεRI signaling, we derived bone marrow-derived mast cells (BMMCs) with reduced or enhanced expression of CSK from wild-type (WT) or PAG knockout (KO) mice and analyzed their FcεRI-mediated activation events. We found that in contrast to PAG-KO cells, antigen-activated BMMCs with CSK knockdown (KD) exhibited significantly higher degranulation, calcium response, and tyrosine phosphorylation of FcεRI, SYK, and phospholipase C. Interestingly, FcεRI-mediated events in BMMCs with PAG-KO were restored upon CSK silencing. BMMCs with CSK-KD/PAG-KO resembled BMMCs with CSK-KD alone. Unexpectedly, cells with CSK-KD showed reduced kinase activity of LYN and decreased phosphorylation of transcription factor STAT5. This was accompanied by impaired production of proinflammatory cytokines and chemokines in antigen-activated cells. In line with this, BMMCs with CSK-KD exhibited enhanced phosphorylation of protein phosphatase SHP-1, which provides a negative feedback loop for regulating phosphorylation of STAT5 and LYN kinase activity. Furthermore, we found that in WT BMMCs SHP-1 forms complexes containing LYN, CSK, and STAT5. Altogether, our data demonstrate that in FcεRI-activated mast cells CSK is a negative regulator of degranulation and chemotaxis, but a positive regulator of adhesion to fibronectin and production of proinflammatory cytokines. Some of these pathways are not dependent on the presence of PAG.

• Klíčová slova
• C-terminal Src kinase, LYN, SHP-1, STAT5, cytokines, degranulation, mast cell, phosphoprotein associated with glycosphingolipid-enriched microdomains,
• MeSH
• analýza rozptylu MeSH
• buňky kostní dřeně fyziologie   MeSH
• C-terminální Src kinasa MeSH
• cytokiny metabolismus   MeSH
• degranulace buněk MeSH
• fibronektiny metabolismus   MeSH
• fosfoproteiny metabolismus   MeSH
• fosforylace MeSH
• genetické vektory MeSH
• HEK293 buňky MeSH
• lidé MeSH
• mastocyty fyziologie   MeSH
• membránové proteiny metabolismus   MeSH
• mezibuněčné signální peptidy a proteiny MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• receptory IgE metabolismus   MeSH
• signální transdukce imunologie   MeSH
• skupina kinas odvozených od src-genu metabolismus   fyziologie   MeSH
• transkripční faktor STAT5 metabolismus   MeSH
• tyrosin metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 6 metabolismus   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• C-terminální Src kinasa MeSH
• CSK protein, human MeSH Prohlížeč
• cytokiny MeSH
• fibronektiny MeSH
• fosfoproteiny MeSH
• lyn protein-tyrosine kinase MeSH Prohlížeč
• membránové proteiny MeSH
• mezibuněčné signální peptidy a proteiny MeSH
• Pag protein, mouse MeSH Prohlížeč
• Pag1 protein, mouse MeSH Prohlížeč
• Ptpn6 protein, mouse MeSH Prohlížeč
• receptory IgE MeSH
• skupina kinas odvozených od src-genu MeSH
• transkripční faktor STAT5 MeSH
• tyrosin MeSH
• tyrosinfosfatasa nereceptorového typu 6 MeSH
• vápník MeSH

Mast cells play a key role in allergy and other inflammatory diseases involving engagement of multivalent antigen with IgE bound to high-affinity IgE receptors (FcεRIs). Aggregation of FcεRIs on mast cells initiates a cascade of signaling events that eventually lead to degranulation, secretion of leukotrienes and prostaglandins, and cytokine and chemokine production contributing to the inflammatory response. Exposure to pro-inflammatory cytokines, chemokines, bacterial and viral products, as well as some other biological products and drugs, induces mast cell transition from the basal state into a primed one, which leads to enhanced response to IgE-antigen complexes. Mast cell priming changes the threshold for antigen-mediated activation by various mechanisms, depending on the priming agent used, which alone usually do not induce mast cell degranulation. In this review, we describe the priming processes induced in mast cells by various cytokines (stem cell factor, interleukins-4, -6 and -33), chemokines, other agents acting through G protein-coupled receptors (adenosine, prostaglandin E2 , sphingosine-1-phosphate, and β-2-adrenergic receptor agonists), toll-like receptors, and various drugs affecting the cytoskeleton. We will review the current knowledge about the molecular mechanisms behind priming of mast cells leading to degranulation and cytokine production and discuss the biological effects of mast cell priming induced by several cytokines.

• Klíčová slova
• cell priming, chemokines, cytokine receptors, cytokines, high-affinity IgE receptor, mast cell,
• MeSH
• alergie imunologie   MeSH
• chemokiny metabolismus   MeSH
• cytokiny metabolismus   MeSH
• degranulace buněk * MeSH
• imunizace MeSH
• imunoglobulin E metabolismus   MeSH
• mastocyty imunologie   MeSH
• mediátory zánětu metabolismus   MeSH
• receptory IgE metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   MeSH
• signální transdukce MeSH
• toll-like receptory metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• chemokiny MeSH
• cytokiny MeSH
• imunoglobulin E MeSH
• mediátory zánětu MeSH
• receptory IgE MeSH
• receptory spřažené s G-proteiny MeSH
• toll-like receptory MeSH

Mast cells are powerful immune modulators of the tissue microenvironment. Within seconds of activation, these cells release a variety of preformed biologically active products, followed by a wave of mediator synthesis and secretion. Increasing evidence suggests that an intricate network of inhibitory and activating receptors, specific signaling pathways, and adaptor proteins governs mast cell responsiveness to stimuli. Here, we discuss the biological and clinical relevance of negative and positive signaling modalities that control mast cell activation, with an emphasis on novel FcεRI regulators, immunoglobulin E (IgE)-independent pathways [e.g., Mas-related G protein-coupled receptor X2 (MRGPRX2)], tetraspanins, and the CD300 family of inhibitory and activating receptors.

• MeSH
• antigen Ki-1 metabolismus   MeSH
• degranulace buněk * MeSH
• imunomodulace MeSH
• kationické antimikrobiální peptidy metabolismus   MeSH
• lidé MeSH
• mastocyty imunologie   MeSH
• neuropeptidy metabolismus   MeSH
• proteiny nervové tkáně metabolismus   MeSH
• receptory IgE metabolismus   MeSH
• receptory neuropeptidů metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   MeSH
• signální transdukce * MeSH
• spinální ganglia metabolismus   MeSH
• tetraspaniny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• antigen Ki-1 MeSH
• FCER1A protein, human MeSH Prohlížeč
• kationické antimikrobiální peptidy MeSH
• MRGPRX2 protein, human MeSH Prohlížeč
• neuropeptidy MeSH
• proteiny nervové tkáně MeSH
• receptory IgE MeSH
• receptory neuropeptidů MeSH
• receptory spřažené s G-proteiny MeSH
• tetraspaniny MeSH

• MeSH
• alergie imunologie   terapie   MeSH
• antiflogistika terapeutické užití   MeSH
• bazofily imunologie   MeSH
• cílená molekulární terapie MeSH
• imunoglobulin E metabolismus   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé MeSH
• mastocyty imunologie   MeSH
• myši MeSH
• receptory IgE metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• dopisy MeSH
• Názvy látek
• antiflogistika MeSH
• imunoglobulin E MeSH
• inhibitory proteinkinas MeSH
• receptory IgE MeSH

Aggregation of the high-affinity receptor for IgE (FcεRI) in mast cells initiates activation events that lead to degranulation and release of inflammatory mediators. To better understand the signaling pathways and genes involved in mast cell activation, we developed a high-throughput mast cell degranulation assay suitable for RNA interference experiments using lentivirus-based short hairpin RNA (shRNA) delivery. We tested 432 shRNAs specific for 144 selected genes for effects on FcεRI-mediated mast cell degranulation and identified 15 potential regulators. In further studies, we focused on galectin-3 (Gal3), identified in this study as a negative regulator of mast cell degranulation. FcεRI-activated cells with Gal3 knockdown exhibited upregulated tyrosine phosphorylation of spleen tyrosine kinase and several other signal transduction molecules and enhanced calcium response. We show that Gal3 promotes internalization of IgE-FcεRI complexes; this may be related to our finding that Gal3 is a positive regulator of FcεRI ubiquitination. Furthermore, we found that Gal3 facilitates mast cell adhesion and motility on fibronectin but negatively regulates antigen-induced chemotaxis. The combined data indicate that Gal3 is involved in both positive and negative regulation of FcεRI-mediated signaling events in mast cells.

• MeSH
• aktiny metabolismus   MeSH
• buněčná adheze MeSH
• chemotaxe MeSH
• cytokiny genetika   metabolismus   MeSH
• fosforylace MeSH
• galektin 3 genetika   metabolismus   MeSH
• lyzozomy metabolismus   MeSH
• malá interferující RNA MeSH
• mastocyty cytologie   fyziologie   MeSH
• myši inbrední BALB C MeSH
• prostaglandin D2 metabolismus   MeSH
• receptory IgE genetika   metabolismus   MeSH
• signální transdukce MeSH
• ubikvitinace MeSH
• vápník metabolismus   MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• aktiny MeSH
• cytokiny MeSH
• galektin 3 MeSH
• Lgals3 protein, mouse MeSH Prohlížeč
• malá interferující RNA MeSH
• prostaglandin D2 MeSH
• receptory IgE MeSH
• vápník MeSH

Single-nucleotide polymorphism studies have linked the chromosome 17q12-q21 region, where the human orosomucoid-like (ORMDL)3 gene is localized, to the risk of asthma and several other inflammatory diseases. Although mast cells are involved in the development of these diseases, the contribution of ORMDL3 to the mast cell physiology is unknown. In this study, we examined the role of ORMDL3 in antigen-induced activation of murine mast cells with reduced or enhanced ORMDL3 expression. Our data show that in antigen-activated mast cells, reduced expression of the ORMDL3 protein had no effect on degranulation and calcium response, but significantly enhanced phosphorylation of AKT kinase at Ser 473 followed by enhanced phosphorylation and degradation of IκBα and translocation of the NF-κB p65 subunit into the nucleus. These events were associated with an increased expression of proinflammatory cytokines (TNF-α, IL-6, and IL-13), chemokines (CCL3 and CCL4), and cyclooxygenase-2 dependent synthesis of prostaglandin D2. Antigen-mediated chemotaxis was also enhanced in ORMDL3-deficient cells, whereas spreading on fibronectin was decreased. On the other hand, increased expression of ORMDL3 had no significant effect on the studied signaling events, except for reduced antigen-mediated chemotaxis. These data were corroborated by increased IgE-antigen-dependent passive cutaneous anaphylaxis in mice with locally silenced ORMDL3 using short interfering RNAs. Our data also show that antigen triggers suppression of ORMDL3 expression in the mast cells. In summary, we provide evidence that downregulation of ORMDL3 expression in mast cells enhances AKT and NF-κB-directed signaling pathways and chemotaxis and contributes to the development of mast cell-mediated local inflammation in vivo.

• Klíčová slova
• Chemotaxis, Degranulation, Mast cell, ORMDL3 knockdown, Proinflammatory cytokines, Prostaglandin D2, RNA interference,
• MeSH
• chemotaxe * MeSH
• cytokiny genetika   imunologie   MeSH
• degranulace buněk * MeSH
• down regulace MeSH
• kultivované buňky MeSH
• mastocyty cytologie   imunologie   metabolismus   MeSH
• membránové proteiny genetika   imunologie   MeSH
• messenger RNA genetika   MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• receptory IgE imunologie   MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytokiny MeSH
• membránové proteiny MeSH
• messenger RNA MeSH
• ORMDL3 protein, mouse MeSH Prohlížeč
• receptory IgE MeSH

Ethanol has multiple effects on biochemical events in a variety of cell types, including the high-affinity immunoglobulin E receptor (FcεRI) signaling in antigen-activated mast cells. However, the underlying molecular mechanism remains unknown. To get better understanding of the effect of ethanol on FcεRI-mediated signaling we examined the effect of short-term treatment with non-toxic concentrations of ethanol on FcεRI signaling events in mouse bone marrow-derived mast cells. We found that 15 min exposure to ethanol inhibited antigen-induced degranulation, calcium mobilization, expression of proinflammatory cytokine genes (tumor necrosis factor-α, interleukin-6, and interleukin-13), and formation of reactive oxygen species in a dose-dependent manner. Removal of cellular cholesterol with methyl-β-cyclodextrin had a similar effect and potentiated some of the inhibitory effects of ethanol. In contrast, exposure of the cells to cholesterol-saturated methyl-β-cyclodextrin abolished in part the inhibitory effect of ethanol on calcium response and production of reactive oxygen species, supporting lipid-centric theories of ethanol action on the earliest stages of mast cell signaling. Further studies showed that exposure to ethanol and/or removal of cholesterol inhibited early FcεRI activation events, including tyrosine phosphorylation of the FcεRI β and γ subunits, SYK kinases, LAT adaptor protein, phospholipase Cγ, STAT5, and AKT and internalization of aggregated FcεRI. Interestingly, ethanol alone, and particularly in combination with methyl-β-cyclodextrin, enhanced phosphorylation of negative regulatory tyrosine 507 of LYN kinase. Finally, we found that ethanol reduced passive cutaneous anaphylactic reaction in mice, suggesting that ethanol also inhibits FcεRI signaling under in vivo conditions. The combined data indicate that ethanol interferes with early antigen-induced signaling events in mast cells by suppressing the function of FcεRI-cholesterol signalosomes at the plasma membrane.

• MeSH
• cholesterol metabolismus   MeSH
• cytokiny genetika   metabolismus   MeSH
• ethanol farmakologie   MeSH
• exprese genu účinky léků   MeSH
• fosforylace MeSH
• mastocyty účinky léků   metabolismus   MeSH
• myši MeSH
• receptory IgE metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• vápník metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cholesterol MeSH
• cytokiny MeSH
• ethanol MeSH
• receptory IgE MeSH
• vápník MeSH

Pimecrolimus (Elidel, SDZ ASM 981) is an anti-inflammatory and immunomodulatory 33-epichloro-derivative of macrolactam ascomycin, with low potential for affecting systemic immune responses compared with other calcineurin inhibitors, cyclosporin A and tacrolimus. Despite numerous studies focused on the mechanism of pimecrolimus action on mast cells, only the single report has addressed pimecrolimus effects on other typical FcεRI-expressing cells, the basophils. Patients allergic to birch pollen (n = 20), hymenopteran venoms (n = 23) and 10 non-allergic volunteers were examined. Primary human basophils pre-treated or not with 0.5-50 μMol pimecrolimus were exposed to various concentrations of recombinant Bet v 1a allergen, bee or wasp venom extracts and anti-IgE for 20 min, and then examined for the expression of CD45, CD193, CD203c, CD63 and CD164 using flow cytometry. The externalization of basophil activation markers (CD63 and CD164) was equally inhibited through pimecrolimus in cells activated by recombinant pollen allergen, hymenopteran venom extracts and anti-IgE. Although the individual response rate was subject to strong variation, importantly, pre-treatment with pimecrolimus lowered the number of activated basophils in response to any of the stimuli in the basophils from all patients. The inhibition was concentration-dependent; approximately half of the basophils were inhibited in the presence of 2.5 mMol pimecrolimus. Pimecrolimus is a valuable new tool for the inhibition of hyper-reactive basophils in patients with pollen allergy and a history of anaphylactic reactions to bee or wasp venoms. Further research should address short-term use of pimecrolimus in vivo in a wide spectrum of allergic diseases.

• MeSH
• alergeny imunologie   MeSH
• alergie farmakoterapie   imunologie   MeSH
• antialergika farmakologie   MeSH
• antiflogistika nesteroidní farmakologie   MeSH
• bazofily účinky léků   imunologie   MeSH
• bříza imunologie   MeSH
• dospělí MeSH
• imunoglobulin E imunologie   MeSH
• kultivované buňky MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• protilátky anti-idiotypické imunologie   MeSH
• receptory IgE imunologie   MeSH
• senioři MeSH
• sezónní alergická rýma farmakoterapie   imunologie   MeSH
• sršňovití imunologie   MeSH
• takrolimus analogy a deriváty   farmakologie   MeSH
• včely imunologie   MeSH
• vosí jedy imunologie   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• senioři MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alergeny MeSH
• anti-IgE antibodies MeSH Prohlížeč
• antialergika MeSH
• antiflogistika nesteroidní MeSH
• imunoglobulin E MeSH
• pimecrolimus MeSH Prohlížeč
• protilátky anti-idiotypické MeSH
• receptory IgE MeSH
• takrolimus MeSH
• vosí jedy MeSH