The systemic anaphylactic reaction is a life-threatening allergic response initiated by activated mast cells. Sphingolipids are an essential player in the development and attenuation of this response. De novo synthesis of sphingolipids in mammalian cells is inhibited by the family of three ORMDL proteins (ORMDL1, 2, and 3). However, the cell and tissue-specific functions of ORMDL proteins in mast cell signaling are poorly understood. This study aimed to determine cross-talk of ORMDL2 and ORMDL3 proteins in IgE-mediated responses. To this end, we prepared mice with whole-body knockout (KO) of Ormdl2 and/or Ormdl3 genes and studied their role in mast cell-dependent activation events in vitro and in vivo. We found that the absence of ORMDL3 in bone marrow-derived mast cells (BMMCs) increased the levels of cellular sphingolipids. Such an increase was further raised by simultaneous ORMDL2 deficiency, which alone had no effect on sphingolipid levels. Cells with double ORMDL2 and ORMDL3 KO exhibited increased intracellular levels of sphingosine-1-phosphate (S1P). Furthermore, we found that concurrent ORMDL2 and ORMDL3 deficiency increased IκB-α phosphorylation, degranulation, and production of IL-4, IL-6, and TNF-α cytokines in antigen-activated mast cells. Interestingly, the chemotaxis towards antigen was increased in all mutant cell types analyzed. Experiments in vivo showed that passive cutaneous anaphylaxis (PCA), which is initiated by mast cell activation, was increased only in ORMDL2,3 double KO mice, supporting our in vitro observations with mast cells. On the other hand, ORMDL3 KO and ORMDL2,3 double KO mice showed faster recovery from passive systemic anaphylaxis, which could be mediated by increased levels of blood S1P presented in such mice. Our findings demonstrate that Ormdl2 deficiency potentiates the ORMDL3-dependent changes in mast cell signaling.

• MeSH
• anafylaxe etiologie   metabolismus   MeSH
• biologické markery MeSH
• chemotaxe imunologie   MeSH
• cytokiny metabolismus   MeSH
• exprese genu MeSH
• lysofosfolipidy krev   metabolismus   MeSH
• mastocyty imunologie   metabolismus   MeSH
• membránové proteiny chemie   nedostatek   genetika   metabolismus   MeSH
• multigenová rodina MeSH
• myši knockoutované MeSH
• myši MeSH
• náchylnost k nemoci MeSH
• pasivní kožní anafylaxe genetika   imunologie   MeSH
• sekvence aminokyselin MeSH
• sfingolipidy krev   metabolismus   MeSH
• sfingosin analogy a deriváty   krev   metabolismus   MeSH
• signální transdukce * MeSH
• vápník metabolismus   MeSH
• vápníková signalizace MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The transmembrane adaptor protein PAG/CBP (here, PAG) is expressed in multiple cell types. Tyrosine-phosphorylated PAG serves as an anchor for C-terminal SRC kinase, an inhibitor of SRC-family kinases. The role of PAG as a negative regulator of immunoreceptor signaling has been examined in several model systems, but no functions in vivo have been determined. Here, we examined the activation of bone marrow-derived mast cells (BMMCs) with PAG knockout and PAG knockdown and the corresponding controls. Our data show that PAG-deficient BMMCs exhibit impaired antigen-induced degranulation, extracellular calcium uptake, tyrosine phosphorylation of several key signaling proteins (including the high-affinity IgE receptor subunits, spleen tyrosine kinase, and phospholipase C), production of several cytokines and chemokines, and chemotaxis. The enzymatic activities of the LYN and FYN kinases were increased in nonactivated cells, suggesting the involvement of a LYN- and/or a FYN-dependent negative regulatory loop. When BMMCs from PAG-knockout mice were activated via the KIT receptor, enhanced degranulation and tyrosine phosphorylation of the receptor were observed. In vivo experiments showed that PAG is a positive regulator of passive systemic anaphylaxis. The combined data indicate that PAG can function as both a positive and a negative regulator of mast cell signaling, depending upon the signaling pathway involved.

• MeSH
• anafylaxe genetika   MeSH
• buňky kostní dřeně metabolismus   fyziologie   MeSH
• degranulace buněk MeSH
• fosfolipasy typu C metabolismus   MeSH
• fosfoproteiny genetika   MeSH
• fosforylace MeSH
• intracelulární signální peptidy a proteiny metabolismus   MeSH
• malá interferující RNA MeSH
• mastocyty metabolismus   fyziologie   MeSH
• membránové proteiny genetika   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• protoonkogenní proteiny c-fyn biosyntéza   MeSH
• protoonkogenní proteiny c-kit metabolismus   MeSH
• receptory IgE metabolismus   MeSH
• RNA interference MeSH
• signální transdukce MeSH
• skupina kinas odvozených od src-genu biosyntéza   metabolismus   MeSH
• tyrosinkinasy metabolismus   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Klíčová slova
• ošetřovatelství,

• NLK Obory
• ošetřovatelství

• MeSH
• alergologie a imunologie MeSH
• autoimunitní nemoci MeSH
• imunita MeSH
• nemoci imunitního systému MeSH
• transplantační imunologie MeSH
• Publikační typ
• monografie MeSH
• příručky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie

• MeSH
• alergologie a imunologie MeSH
• autoimunita MeSH
• imunitní systém MeSH
• nemoci imunitního systému MeSH
• transplantační imunologie MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie

• MeSH
• kůže imunologie   MeSH
• Publikační typ
• sborníky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• dermatovenerologie
• alergologie a imunologie

• MeSH
• imunologické testy metody   MeSH
• nemoci imunitního systému diagnóza   MeSH
• Publikační typ
• kongresy MeSH
• sborníky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie

• MeSH
• alergie MeSH
• dítě MeSH
• Check Tag
• dítě MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie
• pediatrie

• MeSH
• alergologie a imunologie MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• alergologie a imunologie