Substance P downregulates expression of the high affinity IgE receptor (FcεRI) by human mast cells

The effect of the neuropeptide substance P (SP) on human mast cell (MC) phenotype is poorly understood. In this study. SP effects on human MC expression of the high affinity IgE receptor (Fc epsilon RI) were characterized. SP downregulated expression of Fc epsilon RI mRNA and protein by approximately 50% and in a concentration dependent manner, the effect was partially mediated by engagement of the neurokinin-1 receptor (NK1R) and resulted in reduced mast cell activation. Sensitization of MC with IgE prior to SP exposure protected MC from SP-mediated Fc epsilon RI downregulation. SP release may inhibit MC responses to allergens and these results may have implications in neuroinflammatiion and stress. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.