Protective Effect of Genistein against Compound 48/80 Induced Anaphylactoid Shock via Inhibiting MAS Related G Protein-Coupled Receptor X2 (MRGPRX2)

Anaphylactoid shock is a fatal hypersensitivity response caused by non-IgE mediated mast cell activation. These reactions are mediated by a family of G protein-coupled receptors (GPCRs) known as Mas related GPCRX2 (MRGPRX2). Several US FDA approved drugs which are used in day to day life have been reported to cause anaphylactoid shock. Surprisingly, no therapeutic drugs are available which can directly target MRGPRX2 for treatment of anaphylactoid shock. Genistein is a non-steroidal polyphenol known for its diverse physiological and pharmacological activities. In recent studies, Genistein has been reported for its anti-inflammatory activity on mast cells. However, the effects and mechanistic pathways of Genistein on anaphylactoid reaction remain unknown. In the present study, we designed a battery of in-vitro, in-silico and in-vivo experiments to evaluate the anti-anaphylactoid activity of Genistein in order to understand the possible molecular mechanisms of its action. The in-vitro results demonstrated the inhibitory activity of Genistein on MRGPRX2 activation. Further, a mouse model of anaphylactoid shock was used to evaluate the inhibitory activity of Genistein on blood vessel leakage and hind paw edema. Taken together, our findings have demonstrated a therapeutic potential of Genistein as a lead compound in the treatment of anaphylactoid shock via MRGPRX2.

Vasculitis and Anaphylactoid Shock Induced in Mice by Cell Wall Extract of the Fungus Candida metapsilosis

To investigate whether cell wall mannan from Candida metapsilosis induces vasculitis similar to that in Kawasaki syndrome and anaphylactoid shock in mice, we examined the pathogenic effects of C. metapsilosis cell wall extracts. Our results show that intraperitoneal injection of cell wall extracts induced severe coronary arteritis, and intravenous injection induced acute anaphylactoid shock similar to extracts from Candida albicans (C. albicans). Structural analysis of cell wall mannan from C. metapsilosis using NMR spectroscopy showed it to contain only a-mannan, indicating that a-mannan might be contributing to Candida pathogenicity by inducing coronary arteritis and acute shock.