Localization and Up-Regulation of Cysteinyl Leukotriene-2 Receptor in Human Allergic Nasal Mucosa

ABSTRACTBackgroundCysteinyl leukotrienes (CysLTs) are lipid mediators that have been implicated in the pathogenesis of allergic rhinitis. Pharmacological studies using CysLTs indicate that 2 classes of receptors exist, namely, CysLT1 and CysLT2 receptors. The former class of receptors is sensitive to the CysLT1 antagonists currently used to treat asthma and allergic rhinitis, and its localization has been previously examined by our group using immunohistochemistry and in situ hybridization techniques. We investigated the expression and localization of the CysLT2 receptor in human nasal mucosa by western blot and immunohistochemical analyses. Methods: Human turbinates were obtained after turbinectomy from 16 patients with nasal obstruction refractory to medical therapy. To identify the cells expressing the CysLT2 receptor, double immunostaining was performed by using anti-CysLT2 receptor antibody and anti-CD31 (endothelial cell) antibody or anti-smooth muscle actin antibody.ResultsA 39 kDa band was detected on the western blots of human turbinates samples by using the anti- CysLT2 receptor antibody. The expression level of the CysLT2 receptor in patients with nasal allergy was higher than that in patients with non-allergic rhinitis. The immunohistochemical study also showed an intense im- munoreactivity for CysLT2 receptor in both vascular endothelial cells and vascular smooth muscles. Conclusions: The results indicated that the CysLT2 receptor plays a primary role in the vascular responses in the upper respiratory tract.