Oleoylethanolamide ameliorates allergic asthma and atopic dermatitis via activation of GPR119

Serum levels of oleoylethanolamide (OEA) have been associated with the severity of pulmonary diseases, and augmented levels of epidermal OEA have been observed in response to low-grade inflammation in human skin. OEA acts as an endogenous ligand for GPR119; thus, the functional roles of GPR119 were investigated using two murine models. We tested effects of OEA and AR231453, a selective synthetic GPR119 agonist on ovalbumin (OVA)-induced allergic asthma and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis-like models in GPR119 wild-type (WT) and deficient mice. In OVA-induced allergic asthma model, administration of OEA or AR231453 reduced allergic feature, including airway hyperresponsiveness, eosinophil accumulation in bronchoalveolar lavage fluid, airway inflammation, and mucin secretion in the lungs, and both ameliorated DNCB-induced atopic dermatitis-like skin lesions, such as hypertrophy and mast cell accumulation, in GPR119 wild-type (WT) mice, but not in GPR119-deficient mice. OEA or AR231453 treatment reduced OVA-induced increase in pro-inflammatory cytokine expression, and type 2 innate lymphoid cells in the lungs, and both significantly suppressed the DNCB-induced lymph node enlargement and inflammatory Th2/1/17 cells in GPR119 WT mice, but not in GPR119-deficient mice. In RBL-2H3 mast cells, OEA or AR231453 suppressed degranulation and Th2 cytokine expression. These findings suggest that OEA functions to protect against allergic asthma and atopic dermatitis via GPR119 activation by suppressing immune responses in the lungs, lymph nodes, and skin, highlighting GPR119 activation as a therapeutic target for allergic and inflammatory diseases.