Bacterial components regulate the expression of Toll-like receptor 4 on human mast cells.
OBJECTIVE
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.


METHODS
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.


CONCLUSIONS
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.
Kubo
Y
Y
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama Bouji 180, Tokushima 770-8514, Japan.
Fukuishi
N
N
Yoshioka
M
M
Kawasoe
Y
Y
Iriguchi
S
S
Imajo
N
N
Yasui
Y
Y
Matsui
N
N
Akagi
M
M
D002460:Cell Line; D005786:Gene Expression Regulation; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008407:Mast Cells / Q000187:drug effects* / Q000378:metabolism*; D010457:Peptidoglycan / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D013682:Teichoic Acids / Q000494:pharmacology*; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D008070:Lipopolysaccharides; D010457:Peptidoglycan; D012333:RNA, Messenger; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D013682:Teichoic Acids; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha