Regulation of T Helper Cell Type 2 Immune Response by Controlling Beta-2 Adrenergic Receptor in Dendritic Cells of Patients with Allergic Rhinitis

Introduction: Allergic diseases are mediated by T helper cell type 2 (Th2) cells, which are differentiated by dendritic cells (DCs). Recently, it was reported that cAMP concentration in DCs is important for inducing allergic responses. However, the regulatory function of cAMP in DCs in Th2 immune responses is unclear. It was hypothesized that the regulation of G protein-coupled receptors (GPCRs) to increase cAMP levels in DCs would reduce Th2 immune responses. Methods: Human DCs from patients with allergic rhinitis (AR) and from healthy controls were subjected to next-generation sequencing (NGS) to identify potential GPCR. To investigate the functions of GPCR agonists, the in vitro co-culture experiment that THP-1 cells were differentiated into DCs and cultured with human CD4+ T-cells and an AR animal in vivo model were used. Results: Among the GPCRs, the beta-2 adrenergic receptor (ADRB2) of allergic DCs was significantly increased by NGS analysis. The expression of ADRB2 was also increased in Der p 1-treated DCs, which was reduced by treatment with the ADRB2 agonist salbutamol. Salbutamol treatment induced cAMP production in THP-1 derived DCs. In an in vitro co-culture experiment, salbutamol-treated DCs reduced the secretion of Th2 cytokine. In an in vivo AR animal experiment, salbutamol-administered mice showed reduced allergic behavior and Th2 cytokine expression in the nasal mucosa. Conclusions: The regulation of ADRB2 with salbutamol alleviated the allergic response in vitro DC-T cell co-culture and in vivo AR animal models, suggesting that ADRB2 is a therapeutic target for AR and that ADRB2 agonists may be a promising medication for AR.