Dataset for: Orai and TRPC channel characterisation in FcεRI- mediated calcium signaling and mediator secretion in human mast cells

Inappropriate activation of mast cells via the FcεRI receptor leads to the release of
inflammatory mediators and therefore symptoms of allergic disease. Calcium influx
is a critical regulator of mast cell signalling and is required for exocytosis of
preformed mediators and for synthesis of eicosanoids, cytokines and chemokines.
Studies in rodent and human mast cells have identified Orai calcium channels as key
contributors to FcεRI initiated mediator release. However, until now the role of
TRPC calcium channels in FcεRI- mediated human mast cell signalling has not been
published. Here we show evidence for the expression of Orai 1,2 and 3 and TRPC1
and 6 in primary human lung mast cells and the LAD2 human mast cell line; but, we
only find evidence of functional contribution of Orai and not TRPC channels to FcεRImediated
calcium entry. Calcium imaging experiments, utilising an Orai selective
antagonist (Synta66) showed the contribution of Orai to FcεRI-mediated signalling in
human mast cells. Although, the use of a TRPC3/6 selective antagonist and agonist
(GSK-3503A and GSK-2934A, respectively) did not reveal evidence for TRPC6
contribution to FcεRI- mediated calcium signalling in human mast cells. Similarly,
inactivation of STIM1- regulated TRPC1 in human mast cells (as tested by
transfecting LAD2 cells with STIM1-KK684-685EE - TRPC1 gating mutant) failed to alter
FcεRI- mediated calcium signalling in LAD2 human mast cells. Mediator release
assays confirm that FcεRI- mediated calcium influx through Orai is necessary for
histamine and TNFα release but is differentially involved in the generation of
cytokines and eicosanoids.