Bidirectional Role of beta 2-Adrenergic Receptor in Autoimmune Diseases

Disorder of the sympathetic nervous system (SNS) is closely related to the pathogenesis of various autoimmune diseases (ADs). Catecholamine triggered beta2-adrenergic receptor (beta 2-AR) signaling is important in creating a bidirectional response in the progression of ADs due to factors including diverse expression patterns, single nucleotide polymorphisms (SNPs), biased signals, and desensitization of beta 2-AR, as well as different subtypes of G alpha binding to beta 2-AR. In this review, we summarize the actions of beta 2-AR signaling in regulating the functions of immunocytes and in the pathogenesis of ADs, and the application of beta 2-AR agonists or antagonists in treating major types of ADs is also discussed. We suggest that restoring the immune balance via a soft regulation of the expression or activation of beta 2-AR is one of the promising therapeutic strategies for systematic ADs.