Role of transient receptor potential vanilloid 4 channels in an ovalbumin-induced murine food allergic model.

The prevalence of food allergy (FA) has increased worldwide but an effective therapeutic strategy has not been established. Transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive nonselective cation channel, is mainly expressed in the epithelium of various organs. The present study investigated the role of TRPV4 in the pathogenesis of an ovalbumin (OVA)-induced FA model in mice. Wild-type (WT) and TRPV4-deficient (TRPV4KO) mice were sensitized and challenged by OVA to establish FA model. Intestinal tissue samples were processed for biochemical, molecular, and image analyses. Intestinal permeability and antigen uptake assay were conducted using FITC-dextran and OVA-FITC, respectively. TRPV4 was expressed in the colonic epithelium in normal and OVA-treated WT mice. Repeated oral administration of OVA to mice induced systemic allergic symptoms, diarrhea, upregulation of T helper 2 cytokines, OVA-specific immunoglobulin, and FA-related inflammatory cells. These responses were significantly augmented in TRPV4KO mice compared with WT mice. After the induction of FA, the intestinal permeability was significantly increased in TRPV4KO mice compared with WT mice. The expressions of the tight junction protein occludin and adherence junction protein E-cadherin in the colon were significantly lower in TRPV4KO mice compared with WT mice under normal and FA conditions. In addition, the uptake of OVA by CD11c-positive cells was significantly increased in TRPV4KO mice compared with WT mice under FA conditions. These results suggest that epithelial TRPV4 protects against OVA-induced FA symptoms by suppressing the penetration of allergens by maintaining epithelial barrier functions.