Vialinin A Inhibits Microtubule-Mediated Secretory Granule Transport for Degranulation in RBL-2H3 Cells by Targeting the PI3K/Akt Axis

The bioregulatory function of food-derived bioactive factors in complementary therapies for lifestyle-related diseases is attracting worldwide attention. Vialinin A, a p-terphenyl compound isolated from the edible Chinese mushroom Thelephora vialis, inhibits the production and release of tumor necrosis factor α and Syk kinase activity, a key protein involved in the development of allergic rhinitis. However, its effect on other calcium-independent signaling molecules remains unclear. This study investigated the effects of vialinin A on microtubule formation signaling pathways in RBL-2H3 cells. The results showed that vialinin A inhibited Fyn kinase activity and reduced PI3K (class IA) phosphorylation in a dose-dependent manner. Notably, vialinin A inhibited PI3Kδ kinase activity and reduces Akt phosphorylation even at low concentrations. These findings suggest that vialinin A suppresses microtubule formation and granule translocation required for mast cell degranulation through inhibition of the Fyn–PI3K–Akt signaling pathway. Collectively, vialinin A may represent a promising lead compound for the development of anti-allergic therapeutics.