Background As previously shown, the sympathetic nervous system (SNS) shows proinflammatory activity during initiation of arthritis but is anti-inflammatory in established collagen-induced arthritis (CIA). Interleukin 10 (IL-10)-producing B cells suppress arthritis and are a potential target of the SNS because (1) B cells express functional β2-adrenoceptors (β2ARs) and (2) IL-10, at least in monocytes/macrophages, is regulated in a cAMP/PKA/CREB-dependent manner.
Objective To test the hypothesis that anti-inflammatory effects of the SNS in CIA are mediated by stimulating IL-10-producing anti-inflammatory B cells.
Methods Collagen-induced arthritis in DBA/1 mice, sympathectomy, adoptive B cell transfer, in vitro B cell culture, and assessment of B cell IL-10 production.
Results and conclusion Mice treated with B cells from SNS-intact mice showed less severe arthritis than mice treated with B cells from sympathectomised mice. This anti-inflammatory action of B cells from SNS-intact mice correlated with increased IL-10 produced by B cells, which was mediated by norepinephrine (NE), in a β2AR, PKA-dependent manner. However, an NE-mediated increase in IL-10 was seen only in B cells from immunised but not naive mice, explaining in part the anti-inflammatory properties of the SNS in the late phase of arthritis. Finally, animals treated with B cells isolated from immunised mice and activated in vitro in the presence of a β2AR stimulus showed a decrease in arthritis severity in comparison with controls, an approach that might be used for future cellular treatment strategies.
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Funding This study was funded by the institution and by the Deutsche Forschungsgemeinschaft (DFG FOR696, PO801/4-1).
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.