IKK2, calcium, MAP kinase, and PI3 kinase are required for exocytosis and interleukin-8 production in human mast cells stimulated by Trichomonas vaginalis-derived secretory products

Trichomonas vaginalis infection causes vaginitis and cervicitis in women, and asymptomatic urethritis and prostatitis in men. Mast cells play a key role in the inflammatory response against T. vaginalis infection. In this study, we examined the signaling pathways involved in mast cell activation induced by T. vaginalis-derived secretory products (TvSP), focusing on IKK2, calcium, MAP kinase (MAPK), and PI3 kinase (PI3K). TvSP stimulation induced phosphorylation and degradation of IκB, indicating NF-κB activation, and triggered phosphorylation of ERK1/2, p38 MAPK, and AKT. TvSP also increased the surface expression of CD63, a marker of exocytosis, which was reduced by IKK inhibition, calcium chelation, or blockade of PI3K and PKC. Furthermore, inhibition of PI3K or MAPKs decreased TvSP-induced interleukin-8 production. These results suggest that IKK2 and calcium are critical for TvSP-induced degranulation, while PI3K and MAPK pathways contribute to interleukin-8 production in mast cells.