Effect of the house dust mite allergen Der p 1 on tryptase release from human mast cells

Abstract

ABSTRACT. This study aimed to investigate the effects of the house dust mite allergen Der p 1 on the secretion of tryptase from the human mast cell line HMC-1. Flow cytometry was used to determine the expression levels of protease-activated receptor-2 (PAR2) on the surface of HMC-1 cells. HMC-1 cells were treated with Der p 1, SLIGRL-NH 2 (PAR2 agonist), LRGILS-NH 2 (control peptide for PAR2), or Der p 1 + FSLLRY (PAR2 antagonist), and the tryptase levels were measured using enzyme-linked immunosorbent assay. The biological functions of PAR2 were determined using the calcium green indicator, and intracellular calcium fluorescence intensity in the different groups (Der p 1, SLIGRL-NH 2 , LRGILS-NH 2 , Der p 1 + FSLLRY, tryptase, tryptase + FSLLRY, or cell culture medium) was detected by laser scanning confocal microscopy. The mast cells expressed PAR2 receptor on their surfaces. Der p 1 alone induced a significant release of intracellular calcium and tryptase in HMC-1 cells compared with the SLIGRL-NH 2 treatment group and the control group. The combination of Der p 1 and FSLLRY partly inhibited intracellular calcium and tryptase release in HMC-1 cells compared with the Der p 1 treatment group. Moreover, tryptase induced a significant release of intracellular calcium

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“…Furthermore, an anti-ICAM-1 antibody suppressed the tryptase-provoked mast cell accumulation, confirming that tryptase-induced mast cell recruitment was also dependent upon ICAM-1 activity. Tryptase and proinflammatory cytokines such as IL-18 have been reported to correlate well in the plasma of moderate and severe asthmatic patients (Wang et al, 2016). Moreover, tryptase and a PAR2 agonist peptide induced a substantial amount of IL-18 release in mice.…”

“…Moreover, tryptase and a PAR2 agonist peptide induced a substantial amount of IL-18 release in mice. Another study has demonstrated that house dust mites induced the tryptase secretion from a human mast cell line by activating PAR2 receptors on the cell surface, suggesting the role of serine protease/ PAR2 signaling in allergic inflammation (Wang et al, 2016). Overall, serine protease inhibitors or PAR2 antagonist peptides may be promising therapeutic tools for the management of AD.…”