Inhibitory Effect of Carotenoids on the Degranulation of Mast Cells via Suppression of Antigen-induced Aggregation of High Affinity IgE Receptors

Abstract

Carotenoids have been demonstrated to possess antioxidative and anti-inflammatory effects. However, there is no report that the effects of carotenoids on degranulation of mast cell is critical for type I allergy. In this study, we focused on the effect of carotenoids on antigen-induced degranulation of mast cells. Fucoxanthin, astaxanthin, zeaxanthin, and ␤-carotene significantly inhibited the antigen-induced release of ␤-hexosaminidase in rat basophilic leukemia 2H3 cells and mouse bone marrow-derived mast cells. Those carotenoids also inhibited antigen-induced aggregation of the high affinity IgE receptor (Fc⑀RI), which is the most upstream of the degranulating signals of mast cells. Furthermore, carotenoids inhibited Fc⑀RI-mediated intracellular signaling, such as phosphorylation of Lyn kinase and Fyn kinase. It suggests that the inhibitory effect of carotenoids on the degranulation of mast cells were mainly due to suppressing the aggregation of Fc⑀RI followed by intracellular signaling. In addition, those carotenoids inhibited antigen-induced translocation of Fc⑀RI to lipid rafts, which are known as platforms of the aggregation of Fc⑀RI. We assume that carotenoids may modulate the function of lipid rafts and inhibit the translocation of Fc⑀RI to lipid rafts. This is the first report that focused on the aggregation of Fc⑀RI to investigate the mechanism of the inhibitory effects on the degranulation of mast cells and evaluated the functional activity of carotenoids associated with lipid rafts.Mast cells play pivotal roles in inflammation and immediatetype allergic reactions by secreting biologically active substances including histamine, eicosanoids, proteolytic enzymes, cytokines, and chemokines. The antigen-induced aggregation of the high affinity IgE receptor (Fc⑀RI) 2 expressed on the cell surface triggers the degranulation of mast cells. Fc⑀RI has a tetrameric structure comprised of an IgE binding ␣-chain, a ␤-chain, and a disulfide-linked ␥-chain dimer (1). The aggregation of Fc⑀RI by means of multivalent antigen-IgE complexes activates cytosolic Src protein-tyrosine kinases, such as Fyn and Lyn, which then regulate the activation of mast cells (2). Fyn kinase plays a key role in mast cell degranulation and in cytokine production by regulating Gab2 and phosphatidylinositol 3-kinase (3). Phosphorylated Lyn activates immunoreceptor tyrosine-based activation motifs of the ␤-and ␥-chains, and the phosphorylated immunoreceptor tyrosine-based activation motifs of the ␥-chain phosphorylate Syk kinase. Thereafter, a number of other signaling and adaptor molecules, such as phospholipase C␥ and protein kinase C (PKC), are phosphorylated (4). Phospholipase C␥ catalyzes the generation both of inositol 1,4,5-trisphosphate and diacylglycerol. Inositol 1,4,5-trisphosphate is an inducer of intracellular Ca 2ϩ mobilization, which is critical for degranulation, and diacylglycerol is an activator of PKC (5). Activated PKC is translocated from the cytosol to the plasma membrane fraction. PKC regulates many functions of ma...

The Suppressive Effect of a Marine Carotenoid, Fucoxanthin, on Mouse Ear Swelling through Regulation of Activities and mRNA Expression of Inflammation-associated Enzymes

“…The suppression of inflammatory reactions by Fx is attributed to the inhibition of mitogen-activated protein kinase phosphorylation, suppression of the cytoplasmic degradation of B (IκB)-α inhibitors, and decrease of nuclear factor κB (Kim et al, 2010). Fx also suppressed degranulation in rat basophilic leukemia (RBL)-2H3 cells via highaffinity IgE receptor (FcεRI)-mediated intracellular signaling, such as the phosphorylation of Lyn kinase and Fyn kinase (Sakai et al, 2009). In in vivo experiments, intravenously or orally administered Fx suppressed footpad inflammation induced by LPS and the infiltration of inflammatory cells in rat and mouse ear swelling induced by 2,4-dinitrofluorobenzene (DNFB) (Shiratori et al, 2005;Sakai et al, 2011).…”

Could Fucoxanthin Interaction with Lipid Rafts Mediate its Cytotoxicity in Cancer Cells?

“…Structure and biological activity of fucoxanthin and carotenoids in cancer cells [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Biological functions of carotenoids in cell membranes [19][20][21][22] Interaction of carotenoids with lipid rafts [23] Cell model to study the integration of xenobiotics into lipid rafts [24] Antioxidant and pro-oxidant activity of fucoxanthin in animal cells and tissues [25][26][27] Structure and function of lipid rafts in cell membranes [28,29] Targeting lipid rafts in cancer cells [30][31][32][33][34][35][36] Ion channels, lipid rafts and cancer cells [37,38] Lipid rafts, cytoskeleton, cancer cells invasivity and tumor angiogenesis [30,40] …”

“…In the same way, dietary carotenoids such as lutein and zeaxanthin concentrate in the rod outer segment membranes in human retina [22] where they play a key function in eye photoprotection against the deleterious wavelengths of blue light [23]. The first indication that carotenoids may interfere with lipid rafts in the plasma membrane has come from the observation that fucoxanthin, astaxanthin, zeaxanthin and b-carotene inhibit the antigen-induced degranulation of basophiles and mast cells [24]. In these models, it is assumed that fucoxanthin integration into lipid rafts blocks the translocation and aggregation of high affinity IgE receptors (FcεRI) and subsequently inhibits the signaling cascade triggering degranulation [24].…”

“…The first indication that carotenoids may interfere with lipid rafts in the plasma membrane has come from the observation that fucoxanthin, astaxanthin, zeaxanthin and b-carotene inhibit the antigen-induced degranulation of basophiles and mast cells [24]. In these models, it is assumed that fucoxanthin integration into lipid rafts blocks the translocation and aggregation of high affinity IgE receptors (FcεRI) and subsequently inhibits the signaling cascade triggering degranulation [24]. To address this hypothesis in other cell types, we recently investigated the interaction of fucoxanthin with subcellular fractions obtained by ultracentrifugation of Wif-B9 hepatoma cells using the flotation method [25].…”

Suppressive Effects of Carotenoids on the Antigen-induced Degranulation in RBL-2H3 Rat Basophilic Leukemia Cells

“…Antigen-induced mast cell degranulation leads to local inflammation in type I allergies; therefore, natural compounds that can attenuate this degranulation have received particular attention. We have previously shown that astaxanthin, β-carotene, fucoxanthin, and zeaxanthin significantly inhibit antigen-induced degranulation of rat basophilic leukemia cells RBL-2H3 and bone marrow-derived mast cells 7 . However, no information is available regarding the anti-degranulation effects of other carotenoids.…”