3.4.2. Mast Cells
Mast cell activation plays an important role in various immediate allergic diseases. ROS functions in FcεRI-mediated degranulation of mast cells,85,86 and many ROS are generated during the FcεRI-mediated activation of mast cells. Thus, blocking the production of intracellular ROS can prevent the release of FcεRI-mediated allergic mediators from rat mast cells.87 Son et al.stimulated mast cells from WT and Trx1-Tg mice with Ag, DNP-bovine serum albumin; compared with that of WT mice, levels of histamine secreted by mast cells from Trx1-Tg mice were significantly reduced, and the level of intracellular ROS suggested that Trx1 may inhibit mast cell degranulation by blocking ROS production.51 As the underlying mechanism, ROS mainly activates phospholipase Cγ (PLCγ), protein kinase C (PKC) and Ca2+ influx to cause medium release,86,88 whereas Trx1 effectively inhibits PLCγ, PKC and Ca2+ influx in the signal transmission of ROS-activated FcεRI-dependent mast cells (Figure 1c).
βII-tryptase is one of the most abundant proteins stored and released in mast cells; it participates in various acute and chronic allergic processes and is commonly found in patients with asthma and AR.89,90 The redox activity of the allosteric disulphide bond (Cys220-Cys248disulphide bond) in βII-tryptase plays an essential role in exerting enzyme activity, and Trx1 is a related βII-tryptase reducing agentin vivo ; it can selectively reduce the disulphide bonds and potently reduce the catalytic activity of βII-tryptase in the reduced state91 (Figure 1c).