Tumor necrosis factor alpha induces expression of genes for matrix degradation in human chondrocyte-like HCS-2/8 cells through activation of NF-kappaB: abrogation of the tumor necrosis factor alpha effect by proteasome inhibitors.
Tumor necrosis factor alpha (TNF-alpha) has been suggested to induce chondrocytic chondrolysis in both inflammatory and degenerative joint diseases. However, its intracellular signaling pathway leading to the chondrolysis has not been studied in detail. Thus, we investigated whether TNF-alpha activates a transcription factor nuclear factor kappaB (NF-kappaB) in human chondrocyte-like cells (HCS-2/8) and induces the expression of genes involved in the degradation of cartilage matrix. Treatment of the cells with TNF-alpha markedly increased the levels of matrix metalloproteinase 1 (MMP-1), MMP-3, intercellular adhesion molecule 1 (ICAM-1), and cyclo-oxygenase 2 (COX-2) messenger RNAs (mRNAs). The increase in the mRNAs was associated with the activation of p65/p50 heterodimer NF-kappaB. IkappaB-alpha and IkappaB-beta, cytoplasmic molecules preventing the nuclear translocation of NF-kappaB, were degraded rapidly by TNF-alpha followed by their synthesis to the basal level. Treatment with proteasome inhibitors inhibited the degradation of both IkappaB-alpha and IkappaB-beta and prevented the TNF-alpha-dependent nuclear translocation of p65. Furthermore, the inhibitors completely prevented the TNF-alpha-dependent induction of MMP-1, MMP-3, ICAM-1, and COX-2 mRNAs. Thus, it is shown that the activation of p65/p50 NF-kappaB by TNF-alpha plays a cardinal role in inducing the expression of MMP-1, MMP-3, ICAM-1, and COX-2 genes, which are involved in matrix degradation and inflammatory reaction in chondrocytes, leading to chondrocytic chondrolysis.
Sakai
T
T
Department of Endocrinology and Metabolism, Nagoya University, Japan.
Kambe
F
F
Mitsuyama
H
H
Ishiguro
N
N
Kurokouchi
K
K
Takigawa
M
M
Iwata
H
H
Seo
H
H
D015153:Blotting, Western; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism; D051546:Cyclooxygenase 2; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004790:Enzyme Induction / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006801:Humans; D020672:I-kappa B Proteins; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000819:agonists / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D015533:Transcriptional Activation / Q000187:drug effects*; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000494:pharmacology*
D015853:Cysteine Proteinase Inhibitors; D004268:DNA-Binding Proteins; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D007527:Isoenzymes; D007976:Leupeptins; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D000072000:NF-KappaB Inhibitor alpha; D004815:Epidermal Growth Factor; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D003546:Cysteine Endopeptidases; D019278:Matrix Metalloproteinase 3; D020781:Matrix Metalloproteinase 1; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde