Artikel
Beta-2 adrenoceptor signal is augmented in B cells in the course of arthritis and increasing IL-10
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Autoren
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Georg Pongratz
- Universitätsklinik Regensburg und Asklepios Klinikum Bad Abbach, Klinische und experimentelle Rheumatologie und klinische Immunologie und Neuroendokrinoimmunologie, Regensburg
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Clemens Wiest
- Universitätsklinikum Regensburg, Regensburg
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Madlen Melzer
- Universitätsklinikum Regensburg, Regensburg
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Rainer H. Straub
- University Hospital Regensburg, Lab. of Exp. Neuroendocrine Immunology and Rheumatology, Dept. of Internal Medicine, Regensburg
| Veröffentlicht: | 12. September 2014 |
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Gliederung
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Background: Splenic B cells from collagen-induced arthritis (CIA) mice react to a β2-adrenoceptor (AR) stimulus with increased IL-10 production and adoptive transfer of these cells decreases disease activity. However, B cells from unimmunized mice do not adequately increase IL-10. Therefore, we test the hypothesis that sensitivity to catecholamines changes during CIA. Furthermore, we wanted to test if human peripheral blood B cells from osteoarthritis (OA) and rheumatoid arthritis (RA) patients also increase IL-10 following a β2-adrenergic stimulus.
Methods: FACS was used to determine adrenoceptor pathway related proteins (β2-adrenoceptor, G-protein coupled receptor kinase (GRK) 2, phophorylated and unphosphorylated mitogen activated protein kinase p38, and cAMP responsive element binding protein (CREB)) in B cells at different timepoints during CIA. Unstimulated splenic B cells and B cells stimulated with terbutalin, a β2-adrenoceptor agonist, were used. Human B cells were isolated from peripheral blood of patients with OA or RA and stimulated under different conditions with and without terbutalin. IL-10 protein level was determined by ELISA after 5 days of culture.
Results: In the course of CIA the percentage of β2-AR positive B cells increased and stayed above baseline (ANOVA p<0.05). In contrast, the mean fluorescence intensity (MFI) as measure for the number of receptors per cell remained unchanged. MFI for GRK2 decreased and stayed low from day 6 p.i. (ANOVA p<0.0001). The relative increase in phosphorylation of p38 (ANOVA p<0.001) and CREB (ANOVA p<0.001) following a β2-AR stimulus is augmented in the late phase of CIA. In human B cells, similar mechanisms are in place, because β2-AR stimulation of RA but not OA B cells increased IL-10.
Conclusion: The current data show that B cells become more sensitive to β2-AR stimuli in the course of CIA, possibly due to a decrease in GRK2 and increase in the percentage of β2AR expressing splenic B cells. Increased catecholamine sensitivity might support B cell and IL-10 mediated anti-inflammatory mechanisms in the late phase of CIA. A similar mechanims is observed in human peripheral B cells and might be used to improve treatment of autoimmune arthritis.
