Eosinophil peroxidase induces the expression and function of acid-sensing ion channel-3 in allergic rhinitis: in vitro evidence in cultured epithelial cells

Summary Background Acid‐sensing ion channels (ASIC) are a family of acid‐activated ligand‐gated cation channels. As tissue acidosis is a feature of inflammatory conditions, such as allergic rhinitis (AR), we investigated the expression and function of these channels in AR. Objectives The aim of the study was to assess expression and function of ASIC channels in the nasal mucosa of control and AR subjects. Methods Immunohistochemical localization of ASIC receptors and functional responses to lactic acid application were investigated. In vitro studies on cultured epithelial cells were performed to assess underlying mechanisms of ASIC function. Results Lactic acid at pH 7.03 induced a significant rise in nasal fluid secretion that was inhibited by pre‐treatment with the ASIC inhibitor amiloride in AR subjects (n = 19). Quantitative PCR on cDNA isolated from nasal biopsies from control and AR subjects demonstrated that ASIC‐1 was equally expressed in both populations, but ASIC‐3 was significantly more highly expressed in AR (P