α-Linolenic acid attenuates pseudo-allergic reactions by inhibiting Lyn kinase activity

Background: Pseudo-allergic reactions are potentially fatal hypersensitivity responses caused by mast cell activation. alpha-linolenic acid (ALA) is known for its anti-allergic properties. However, its potential anti-pseudo-allergic effects were not much investigated. Purpose: To investigate the inhibitory effects of ALA on IgE-independent allergy in vitro, and in vivo, as well as the mechanism underlying its effects. Methods/study designs: The anti-anaphylactoid activity of ALA was evaluated in passive cutaneous anaphylaxis reaction (PCA) and systemic anaphylaxis models. Calcium imaging was used to assess intracellular Ca2+ mobilization. The release of cytokines and chemokines was measured using enzyme immunoassay kits. Western blot analysis was conducted to investigate the molecules of Lyn-PLC gamma-IP3R-Ca2+ and Lyn-p38/NF-kappa B signaling pathway. Results: ALA (0, 1.0, 2.0, and 4.0 mg/kg) dose-dependently reduced serum histamine, chemokine release, vasodilation, eosinophil infiltration, and the percentage of degranulated mast cells in C57BL/6 mice. In addition, ALA (0, 50, 100, and 200 mu M) reduced Compound 48/80 (C48/80) (30 mu g/ml)-or Substance P (SP) (4 mu g/ml)induced calcium influx, mast cell degranulation and cytokines and chemokine release in Laboratory of Allergic Disease 2 (LAD2) cells via Lyn-PLC gamma-IP3R-Ca2+ and Lyn-p38/NF-kappa B signaling pathway. Moreover, ALA (0, 50, 100, and 200 mu M) inhibited C48/80 (30 mu g/ml)- and SP (4 mu g/ml)-induced calcium influx in Mas-related Gprotein coupled receptor member X2 (MrgX2)-HEK293 cells and in vitro kinase assays confirmed that ALA inhibited the activity of Lyn kinase. In response to 200 mu M of ALA, the activity of Lyn kinase by (7.296 +/- 0.03751) x 10(-5) units/mu l and decreased compared with C48/80 (30 mu g/ml) by (8.572 +/- 0.1365) x10(-5) units/mu l. Conclusion: Our results demonstrate that ALA might be a potential Lyn kinase inhibitor, which could be used to treat pseudo-allergic reaction-related diseases such as urticaria.