Sauchinone suppresses FcεRI-mediated mast cell signaling and anaphylaxis through regulation of LKB1/AMPK axis and SHP-1-Syk signaling module.

Sauchinone, the biologically active lignan of Saururus chinensis, has been reported to have anti-inflammatory, antitumor, antioxidant, and hepatoprotective properties. However, little is known about the effect of sauchinone on FcεRI-mediated mast cell activation. The aim of this study was to evaluate the anti-allergic activity of sauchinone and the underlying mechanism using mouse bone marrow-derived mast cells (BMMCs) and the mast cell-mediated passive cutaneous anaphylaxis (PCA) model. Sauchinone markedly suppressed FcεRI-mediated activation of positive signaling mediators, including Syk, linker for activation of T cells (LAT), phospholipase C (PLC)γ, mitogen-activated protein (MAP) kinases, Akt, IκB kinase (IKK), and intracellular Ca²⁺, and increased the activation of negative signaling mediators, including liver kinase B (LKB)1/AMP-activated protein kinase (AMPK) and Src homology 2 domain-containing protein tyrosine phosphatase (SHP)-1. Interestingly, sauchinone increased the interaction between SHP-1 and Syk. Consequently, sauchinone significantly suppressed FcεRI-mediated BMMC degranulation and synthesis of eicosanoids and cytokines. These inhibitory effects of sauchinone were diminished in BMMCs treated with siRNAs targeting LKB1, AMPKα2, or SHP-1, and in BMMCs isolated from AMPKα2-deficient mice. In addition, administration of sauchinone markedly suppressed the IgE-mediated PCA reaction in wild-type mice, and this inhibitory effect was significantly reduced in AMPKα2^-/- mice. Taken together, these data suggest that sauchinone suppresses FcεRI-mediated mast cell activation and anaphylaxis through modulation of the LKB1/AMPK and SHP-1/Syk pathways. Therefore, sauchinone might be a potential therapeutic agent for the treatment of allergic inflammatory diseases.