Suppression of mast cell degranulation by a novel ceramide kinase inhibitor, the F-12509A olefin isomer K1

Abstract

Antigen-induced degranulation of mast cells plays a pivotal role in allergic and inflammatory responses. Recently, ceramide kinase (CERK) and its phosphorylated product ceramide 1-phosphate (C1P) have emerged as important players in mast cell degranulation. Here, we describe the synthesis of a novel F-12509A olefin isomer, K1, as an effective CERK inhibitor. In vitro kinase assays demonstrated that K1 effectively inhibits CERK without inhibiting sphingosine kinase and diacylglycerol kinase. Treating RBL-2H3 cells with K1 reduced cellular C1P levels to 40% yet had no effect on cell growth. Furthermore, treatment with K1 significantly suppressed both calcium ionophore-and IgE/antigen-induced degranulation, indicating that K1 interferes with signals that happen downstream of Ca 2+ mobilization. Finally, we show that K1 affects neither IgE/antigen-induced global tyrosine phosphorylation nor subsequent Ca 2+ elevation, suggesting a specificity for CERK-mediated signals. Our novel CERK inhibitor provides a useful tool for studying the biological functions of CERK and C1P. Moreover, to our knowledge, this is the first report demonstrating that inhibition of CERK suppresses IgE/antigen-induced mast cell degranulation. This finding suggests that CERK inhibitors might be a potential therapeutic tool in the treatment of allergic diseases.

Ceramide kinase uses ceramide provided by ceramide transport protein: localization to organelles of eicosanoid synthesis

“…In this regard, a recent report by Igarashi and coworkers (11,41) demonstrated that C1P induced the release of b-hexosaminidase from RBL-2H3 cells via CERK. The localization of CERK to the trans-Golgi apparatus is also in accordance with the report by Carre and coworkers (10), who reported that overexpression of CERK tagged with green fluorescent protein (not endogenous CERK) in COS-1 cells results in localization to perinuclear/Golgi membrane using a fluorescent ceramide as a Golgi marker.…”

Targeting Ceramide Metabolism with a Potent and Specific Ceramide Kinase Inhibitor

“…CerK biology is still poorly understood. The discovery that C1P could activate the cytosolic phospholipase A2 ␣ isoform (PLA2G4A) in A549 human lung adenocarcinoma cells (Pettus et al, 2003(Pettus et al, , 2004) stimulated a search for CerK inhibitors that might have anti-inflammatory properties (Kim et al, 2005;Munagala et al, 2007). However, despite significant progress in characterizing in vitro the interaction of C1P and PLA2G4A (Stahelin et al, 2007), evidence that a C1P-PLA2G4A interaction plays a role in the cell or in vivo is lacking.…”

“Inside-Out” Signaling of Sphingosine-1-Phosphate: Therapeutic Targets

“…B-5354c, isolated from a novel marine bacterium, blocked the production of S1P and caused sphingosine to accumulate in sheep erythrocytes (Ochi et al, 2004). F-12509a, a sesquiterpene quinone isolated from a culture broth of the discomycete, Trichopezizella barbata SANK 25395, was shown to be a competitive inhibitor of SphK1 (Kono et al, 2000b;Kim et al, 2005). Although these natural products are moderately potent SphK inhibitors, the possibility of large-scale production remains unknown, and their synthesis seems impractical because of their complex structures.…”