Interleukin-17 and lipopolysaccharides synergistically induce cyclooxygenase-2 expression in human intestinal myofibroblasts.
BACKGROUND
Colonic subepithelial myofibroblasts (SEMF) play a role in the modulation of mucosal inflammatory responses via the secretion of various inflammatory mediators. In the present study the effects of interleukin (IL)-17 and lipopolysaccharides (LPS) on cyclooxygenase (COX) expression in colonic SEMF were investigated.


METHODS
The expression of COX-1 and -2 proteins and mRNAs were determined by western and northern blotting, respectively. Nuclear factor (NF)-kappaB DNA binding activities were evaluated by electrophoretic gel mobility shift assays (EMSA).


RESULTS
The expression of COX-2 protein and mRNA was rapidly induced by the addition of IL-17 and LPS, whereas COX-1 expression was not affected by these factors. The effects of IL-17 and LPS were detected in a dose- and time-dependent manner. Furthermore, IL-17 and LPS synergistically induced COX-2 mRNA and protein expression. The EMSA demonstrated that the addition of IL-17 and LPS induced NF-kappaB activation within 1.5 h after stimulation, and a blockade of NF-kappaB activation by a recombinant adenovirus containing a stable form of IkappaBa markedly reduced the IL-17- and LPS-induced COX-2 mRNA expression. In these cells, the expression of Toll-like receptor (TLR)-4, which is a cellular receptor for LPS, was detected.


CONCLUSIONS
Interleukin-17 and LPS play an important role in the induction of COX-2 in SEMF. These findings suggest that COX-2 expression and prostaglandin synthesis might be regulated by both T-cell-derived factor (IL-17) and bacterial products (LPS) in the inflamed mucosa.
Zhang
Zhuobin
Z
Department of Internal Medicine, Shiga University of Medical Science, Seta Tukinowa, Otsu, Japan.
Andoh
Akira
A
Inatomi
Osamu
O
Bamba
Shigeki
S
Takayanagi
Atsushi
A
Shimizu
Nobuyoshi
N
Fujiyama
Yoshihide
Y
D015152:Blotting, Northern; D015153:Blotting, Western; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005347:Fibroblasts / Q000187:drug effects*; D006801:Humans; D020381:Interleukin-17 / Q000494:pharmacology*; D007422:Intestines / Q000187:drug effects / Q000201:enzymology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013997:Time Factors
D020381:Interleukin-17; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D012333:RNA, Messenger; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases