Summary: New research highlights sex-specific differences in dopamine-regulated signaling within B cells and suggests that dopamine may promote inflammation in women with rheumatoid arthritis.
Source: IfADo
Rheumatoid arthritis (RA) is an autoimmune condition marked by chronic inflammation of the joints, often causing pain, loss of function, and long-term disability. The disease shows clear differences in incidence and course between the sexes.
Scientists at the Leibniz Research Centre for Working Environment and Human Factors in Dortmund (IfADo) investigated how the neurotransmitter dopamine affects immune cells in RA patients, with particular attention to sex-specific responses.
Their results point to a divergence in how dopamine-regulated signaling operates in B cells from male and female patients. In female RA patients, dopamine-related pathways appear to have a pro-inflammatory effect, a finding with potential diagnostic and therapeutic implications.
Led by Prof. Dr. Silvia Capellino, the research team identified that dopamine-responsive signaling in B cells differs between women and men with RA. This sex-dependent behavior of B cells could help explain why women more commonly develop RA and often experience a different disease progression than men.
In the cohort studied, the link between dopamine signaling in immune cells and clinical measures—such as disease duration and degrees of functional disability—was particularly apparent in women. Based on these observations, the authors propose that a dopamine-related diagnostic marker could be useful specifically for female RA patients.
Dopamine and immune regulation
RA affects women more frequently than men, and disease activity and outcomes often differ by sex. Sex hormones, especially estrogens, are known to shape immune responses and may contribute to these differences by promoting inflammatory pathways.
Beyond hormonal effects, the nervous system exerts control over immune function through neurotransmitters. Dopamine, widely recognized for its role in the brain, also influences peripheral tissues and immune cells. Recent work has shown that dopaminergic signaling can reshape immune responses, and this new IfADo study explores that interaction in the context of RA.
The researchers suggest that estrogens might modulate dopamine-controlled signaling pathways, thereby indirectly altering immune behavior. A follow-up project is planned to investigate how estrogen and dopamine pathways interact to affect immune cell function, especially in women with RA.
About this rheumatoid arthritis research news
Author: Anne Gregory
Source: IfADo
Contact: Anne Gregory – IfADo
Image: The image is in the public domain
Original Research: Open access.
“Dopamine receptor 1 expressing B cells exert a proinflammatory role in female patients with rheumatoid arthritis” by Karolin Wieber et al. Scientific Reports
Abstract
Dopamine receptor 1 expressing B cells exert a proinflammatory role in female patients with rheumatoid arthritis
Rheumatoid arthritis (RA) is a chronic autoimmune disease that shows a distinct sex-bias. Prior evidence implicated dopamine in RA pathogenesis and suggested that dopaminergic signaling can be influenced by estrogens.
To clarify how dopamine affects B cell function in RA and to explore sex-specific differences, the researchers recruited healthy controls (HC, n = 64) and RA patients (n = 61). They used flow cytometry to examine expression of dopamine receptors D1–D5 on peripheral blood mononuclear cells (PBMCs), stimulated D1-like receptors in vitro to observe effects on B cell activation and proliferation, and measured cytokine secretion and cellular dopamine content by ELISA.
All five dopamine receptors were detected on PBMCs from both healthy individuals and RA patients. However, dopamine content within PBMCs and the frequency of D1 receptor–expressing B cells were significantly elevated in female RA patients. Importantly, expression of the D1 receptor on B cells correlated positively with disease duration and severity in women but not in men. Combined stimulation of B cells and D1-like receptors led to increased secretion of proinflammatory mediators IL-8 and CCL3 from PBMCs of female RA patients compared to healthy controls.
These findings reveal sex-specific differences in dopaminergic pathways in RA and support a proinflammatory role for the D1 receptor pathway in women. The results open avenues for sex-tailored diagnostic strategies and point toward the D1-like receptor pathway as a potential target for therapeutic intervention in female patients. Ongoing work aims to dissect how estrogens interact with dopaminergic signaling to influence immune responses in RA.