Dopamine Uses the DRD5-ARRB2-PP2A Signaling Axis to Block the TRAF6-Mediated NF-κB Pathway and Suppress Systemic Inflammation

The functional relevance and mechanistic basis of the effects of the neurotransmitter dopamine (DA) on inflammation remain unclear. Here we reveal that DA inhibited TLR2-induced NF-κB activation and inflammation via the DRD5 receptor in macrophages. We found that the DRD5 receptor, via the EFD and IYX(X)I/L motifs in its CT and IC3 loop, respectively, can directly recruit TRAF6 and its negative regulator ARRB2 to form a multi-protein complex also containing downstream signaling proteins, such as TAK1, IKKs, and PP2A, that impairs TRAF6-mediated activation of NF-κB and expression of pro-inflammatory genes. Furthermore, the DA-DRD5-ARRB2-PP2A signaling axis can prevent S. aureus-induced inflammation and protect mice against S. aureus-induced sepsis and meningitis after DA treatment. Collectively, these findings provide the first demonstration of DA-DRD5 signaling acting to control inflammation and a detailed delineation of the underlying mechanism and identify the DRD5-ARRB2-PP2A axis as a potential target for future therapy of inflammation-associated diseases such as meningitis and sepsis.,Crown Copyright © 2020. Published by Elsevier Inc. All rights reserved.