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Effects of dexamethasone on purinergic signaling in murine mast cells: Selective suppression of P2X7 receptor expression

Yoshida, Kazuki, Ito, Masaaki, Hoshino, Yui, Matsuoka, Isao
Biochemical and biophysical research communications 2017
adenosine triphosphate, antagonists, anti-allergic agents, calcium, dexamethasone, ethidium, flow cytometry, glucocorticoid receptors, mast cells, messenger RNA, mice, oral administration, prednisolone, purinergic receptors
Mast cells express many different purinergic receptors, including ionotropic P2X4 and P2X7, which recognize the accumulation of extracellular ATP released from activated and/or damaged cells. This results in the stimulation of mast cell functions. In this study, we investigated the effects of dexamethasone (Dex), an anti-inflammatory glucocorticoid widely used for the treatment of allergic disease, on purinergic receptor expression in mouse bone marrow-derived mast cells (BMMCs). Treatment of BMMCs with Dex decreased P2X7 receptor mRNA levels in a time- and concentration-dependent manner without affecting the expression of other purinergic receptor subtypes. Accordingly, fluorescence-activated cell sorting analysis revealed that Dex treatment also decreased P2X7 receptor protein levels. This effect was mimicked by prednisolone, another anti-inflammatory glucocorticoid, and was inhibited by the glucocorticoid receptor antagonist mifepristone. Functionally, treatment of BMMCs with Dex impaired the P2X7-mediated rise in intracellular Ca2+ concentration, degranulation, and ethidium uptake, a response relevant to receptor-pore formation. Finally, oral administration of Dex to C57BL/6 mice in vivo resulted in a significant decrease in P2X7 receptor expression in peritoneal mast cells. These results suggest that reduction of P2X7 receptor expression in mast cells might be one of the anti-allergic mechanisms of Dex.