Role of NF-kappaB in TNF-alpha-induced COX-2 expression in synovial fibroblasts from human TMJ.
In the temporomandibular joint (TMJ) synovium, cyclo-oxygenase-2 (COX-2) expression has been believed to be directly related to joint pain and synovitis. Here we investigated the role of Nuclear Factor kappaB (NF-kappaB) in the regulation of COX-2 expression in synovial fibroblasts from human TMJ induced by tumor necrosis factor-alpha (TNF-alpha). By reverse-transcriptase/polymerase chain-reaction (RT-PCR) and Western blotting analysis, TNF-alpha induced a dose- and time-dependent increase in COX-2 expression. Electrophoretic mobility shift assay (EMSA) revealed that transient NF-kappaB activation in the COX-2 promoter was triggered by TNF-alpha. In parallel with transient NF-kappaB activation, the rapid translocation of NF-kappaB, particularly the p65 subunit, from the cytoplasm into the nucleus was demonstrated. Pre-treatment with pyrolidine dithiocarbamate (PDTC), one of the NF-kappaB inhibitors, prevented binding to the COX-2 promoter and expression of COX-2 protein in response to TNF-alpha. These findings indicate that activation of NF-kappaB is responsible for TNF-alpha-induced COX-2 expression in synovial fibroblasts from the TMJ.
Ke
J
J
Key Laboratory for Oral Biomedical Engineering, Ministry of Education, PR China.
Long
X
X
Liu
Y
Y
Zhang
Y F
YF
Li
J
J
Fang
W
W
Meng
Q G
QG
D021581:Active Transport, Cell Nucleus; D000293:Adolescent; D000328:Adult; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000032:analysis / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008335:Mandibular Condyle / Q000293:injuries; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013582:Synovial Fluid / Q000166:cytology / Q000378:metabolism*; D013704:Temporomandibular Joint / Q000166:cytology / Q000378:metabolism; D013705:Temporomandibular Joint Disorders / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000032:analysis / Q000378:metabolism; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
D016328:NF-kappa B; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2