Inhibitory effects of quail egg on mast cells degranulation by suppressing PAR2-mediated MAPK and NF-kB activation

Quail egg (QE) has been reported to possess an anti-allergic and anti-inflammatory activity. We have demonstrated that whole QE was able to attenuate the allergic symptoms in food allergy-induced EoE murine model, but whether QE albumen or QE yolk plays a more important role still remains unclear.

In this current study, we investigated the suppressive role of QE in mast cell degranulation and cytokine production of the effect phase response.

A passive cutaneous anaphylaxis (PCA) mouse model was used to confirm the anti-allergic effect of QE. Besides, HMC-1 cell model was used to study its suppressive role in more detail. In this in vitro study, we divided QE into three groups: whole QE, QE albumen, and QE yolk. The effect of QE treatment on mast cell degranulation and intracellular calcium influx was investigated. Moreover, the effect of QE allergy- related mediators, genes, and proteins were also assessed by ELISA, RT-PCR, and western blotting.

Our data showed that the extent of mast cell degranulation-mediated ear vascular permeability in IgE-mediated PCA mice treated with whole QE (17 mg/kg) was decreased significantly up to 43.31 ± 0.42% reduction. HMC-1 cell-based immunological assay in vitro indicated that QE, particularly its albumen, acted as a 'mast cell stabilizer'. Under the concentration of 70 μg/mL, QE albumen effectively suppressed the releases of β-hexosaminidase, histamine, and tryptase, as well as Th2 and pro-inflammatory cytokine production; reached 30 up to 50% reduction. Besides, QE albumen was also able to significantly modulate the upregulation of IL-10 up to 58.30 ± 5.9%. Interestingly, our data indicated that QE yolk still had a significant inhibitory effect on modulating Th2 cytokines in its highest concentration (100 μg/mL), while QE albumen showed no inhibitory effect. Western blot analysis showed QE albumen effectively down-regulated the expressions of calcium-related protein (TRPC1, Orai1, STIM1, PLC-γ and IP3R), facilitated the reduction of PAR-2 and induced the reduction of phosphorylation of JNK, IKKα, p50 and p65 protein expressions.

As confirmed by PCA and HMC-1 cell-based immunology assay, QE albumen and QE yolk may work together through exerting anti-allergy activity and can be used as a potential anti-allergic nutrient in the future.