Zyxin-a novel detrimental target, is inhibited by Saikosaponin A during allergic asthma

Background: Allergic asthma is a heterogeneous disease involving numerous inflammatory cells. Mast cell (MC) plays a key role during allergic asthma. Saikosaponin A (SSA) inhibits MC activation and ameliorates allergic asthma, however, its underlying mechanism remains unclear. This study aims to identify SSA-binding proteins and reveal their functions.

Methods: C57BL/6J mice were used to establish allergic asthma models to evaluate therapeutic effect of SSA. Protein microarray, RNA-seq, surface plasmon resonance (SPR), and pull-down assay were used to explore and validate the binding proteins of SSA. The functions of Zyxin were explored by knockdown and overexpression in LAD2. Zyxin knockout mice were constructed to investigate the role of Zyxin in allergic asthma.

Results: SSA alleviates allergic asthma and inhibits MC activation. Zyxin was confirmed as a binding protein of SSA. In vitro experiments proved the crucial role of Zyxin in mast cell exocytosis. Zyxin Ser142/143 is phosphorylated during MC activation, which can be inhibited by SSA. In vivo studies showed that Zyxin expression in MC has detrimental effects, while its deficiency ameliorates allergic asthma.

Conclusion: Our results verified the detrimental effect of Zyxin in allergic asthma for the first time. We also innovatively demonstrated that SSA exerts inhibitory effects on MC activation and allergic asthma by directly binding to and inhibiting Zyxin phosphorylation.

Allergic asthma; Mast cell; Saikosaponin A; Zyxin.