Previous study has shown that cross-linking of FcεRI activates PI3K signalling

pathway, leading to intracellular ROS production [25]. To explore whether OVA challenge–induced ROS production and subsequent activation of SOCs are related to PI3K activation, we explored the effect of PI3K inhibitor Wortmannin on ROS production and Ca2+ signalling in OVA-activated mast cells. The results demonstrated that Wortmannin (100 nm, 15 min) pretreatment significantly decreased PD98059 intracellular ROS production by ~30%. Mast cell activation–induced histamine release was similarly reduced (~30%) by inhibiting PI3K pathway. With the reduction of ROS, Ca2+ increase through SOCs in OVA-activated mast cells was diminished by ~30% (Fig. 6A,B). Consistently, the protein expressions of Orai1 and STIM1 were attenuated by ~40% and ~30%, respectively (Fig. 6C,D). We also found that inhibition of PI3K pathway reduced mast cell activation–induced histamine release (~30%) and intracellular ROS Compound Library in vivo production (~30%). The results indicate that PI3K-mediated ROS generation is involved in the regulation of SOCs activity and mast cell activation under food-allergic condition (Fig. 6E,F). Previous studies have demonstrated that mast cells play a critical role in allergic diseases. Using OVA-stimulated food-allergic rat model, we revealed that

mast cells were recruited and activated in the damaged intestinal tissues and peritoneal lavage, and Th2 cytokines and IgE were significantly increased, confirming

the notion that mast cells contribute to the pathogenesis of food allergy. In this study, we demonstrated that the underlying mechanism for mast cell activation Adenosine triphosphate in the food-allergic mouse model is related to increased Ca2+ entry through SOCs. Furthermore, we found that OVA stimulation increased intracellular ROS production in mast cells through activation of phosphoinositide 3-kinase (PI3K) pathway, which results in upregulation of the expression levels of the major subunits of SOC, Orai1 and STIM1, leading to the enhancement of SOC activity and subsequent mast cell activation. Food allergy is one type of adverse reactions to non-toxic food that involves an abnormal immunological response to specific protein(s) in food. Allergens from egg seem to be one of the most frequent causes of food-allergic reaction as reported [26]. In the present study, we use OVA, which comprise 50% of the protein in egg white, to induce food allergy as previously reported [17, 27, 28]. According to our results, the food-allergic model in Brown-Norway rats has been successfully re-established. The OVA-challenged rat showed typical allergic appearances, including puffiness and redness around the eyes and mouth, diarrhoea, pilar erecti, reduced activity and/or decreased activity with increased respiratory rate and cyanosis around the mouth and tail.