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Updated: Jul 15, 2026

Investigating Mast Cell Secretory Granules; from Biosynthesis to Exocytosis
Published on: January 26, 2015
Bacterial components regulate the expression of Toll-like receptor 4 on human mast cells
Y Kubo1, N Fukuishi, M Yoshioka
1Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama Bouji 180, Tokushima 770-8514, Japan.
Objectives And Design:
The aim of this study was to investigate whether the exposure of mast cells (MCs) to bacterial components affects the expression of Toll-like receptor (TLR) 4, and to elucidate the behavior of MCs during the early response to infection.
Materials:
Two human MC lines, HMC-1 and LAD2, were employed. Messenger RNA expression was observed by RT and real-time PCR. TLR4 expression was determined by Western blotting. TNF-alpha secretion was analyzed with ELISA. The degranulation ratio was measured with betahexosaminidase assay.
Results:
Although bacterial components increased TLR4 mRNA, only lipopolysaccharide (LPS) augmented the TLR4 protein expression. LAD2 pre-treated with LPS for 8 h resulted in 2-fold increased TNF-alpha secretion on LPS restimulation.
Conclusion:
These results suggest that the exposure of MCs to LPS may reinforce the innate immune system due to up-regulation of MC TLR4, followed by increased TNF-alpha release.
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