Abstract
Purpose:
We previously reported that (1) coculture between human mast cells and conjunctival epithelial cells induce CCL2 expression in mast cells, (2) CCL2 stimulation of mast cells could induce piecemeal degranulation (PMD) of mast cells, and (3) increased CCL2 expression and PMD was observed in the giant papillae of vernal keratoconjunctivitis (VKC) patients. The CCL2 induction in mast cells was dependent on the conjunctival epithelial cell derived factor(s), therefore we examined the role of substance P (SP) as a candidate for the epithelial cell derived factor inducing CCL2 expression in mast cells.
Methods:
Human cultured mast cells (LAD2) were stimulated with SP for 24hours. Realtime PCR analysis and CCL2 ELISA assay were carried out to quantitate CCL2 expression in LAD2 cells. SP inhibitor (L-703606 oxalate salt hydrate) was added to the coculture model and CCL2 expression was also examined.
Results:
CCL2 mRNA expression in LAD2 cells was increased 1.49±0.07 fold (mean±SD) by SP stimulation (10uM). CCL2 concentration in the LAD2 culture supernatants was increased 1.69 fold (from 585 pg/ml to 994 pg/ml) by SP stimulation (10uM). SP inhibitor (1nM) partially suppressed CCL2 upregulation in the coculture model (22% reduction). CCL2 concentration in the LAD2 culture supernatants was decreased 15% (from 844pg/ml to 718pg/ml) by SP inhibitor (1uM).
Conclusions:
Our result showed that SP could be one of the possible epithelial cell derived factor(s) that modulate CCL2 expression in mast cells.
Keywords: 475 conjunctivitis