Effects Of Fostriecin On Beta 2-Adrenoceptor-Driven Responses In Human Mast Cells

As part of the intracellular processes leading to mast cell and basophil activation, phosphorylation of key substrates is likely to be important. These processes, mediated by phosphatases, are responsible for regulating phosphorylation. The aim of the present study was to determine effects fostriecin - a selective inhibitor of PP2A (protein phosphatase-2) - on beta 2-adrenoceptor-driven responses in human mast cells. Here, the effects of fostriecin (PP inhibitors) on the inhibition of histamine release from HLMC, on beta-adrenoceptor- driven responses in mast cells and on desensitization were investigated. Long-term incubation (24 h) of mast cells with fostriecin (10(-6) M) resulted in a significant (p < 0.001) reduction in the maximal response (from 41.2 [+/- 3.0] to 29.9 [+/- 4.2] %) to salbutamol following fostriecin treatment. The results showed that fostriecin pretreatment significantly attenuated the inhibitory effects of salbutamol. Overall, the present study suggested that PP2A has an important role in regulating mast cell beta 2-adrenoceptors.