Flavones suppress the expression of the high-affinity IgE receptor FCεRI in human basophilic KU812 cells

We examined the effect of flavones on the expression of the high-affinity IgE receptor FcεRI, which plays a central role in the IgE-mediated allergic response. Flow cytometric analysis showed that the flavones chrysin and apigenin were able to reduce the cell surface expression of FcεRI in human basophilic KU812 cells. Immunoblot analysis revealed that the total cellular expression of the FcεRI α and γ chains decreased upon treatment with chrysin and apigenin. Moreover, the level of mRNA expression of the FcεRI α and γ chains also decreased when the cells were cultured with the two flavones. Previously, we demonstrated that the reduction of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation was involved in the downregulation of FcεRI expression. The two flavones were shown to reduce the level of ERK1/2 phosphorylation. These results suggested that chrysin and apigenin have the ability to downregulate FcεRI expression and this suppressive effect may be due to the reduction of ERK1/2 phosphorylation.