Apoptosis signal-regulating kinase 1 is mediated in TNF-α-induced CCL2 expression in human synovial fibroblasts.
Tumor necrosis factor-α (TNF-α), a pro-inflammatory cytokine with a critical role in osteoarthritis (OA), was primarily produced by monocytes/macrophages and plays a crucial role in the inflammatory response. Here, we investigated the intracellular signaling pathways involved in TNF-α-induced monocyte chemoattractant protein 1 (MCP-1)/CCL2 expression in human synovial fibroblast cells. Stimulation of synovial fibroblasts (OASF) with TNF-α induced concentration- and time-dependent increases in CCL2 expression. TNF-α-mediated CCL2 production was attenuated by TNFR1 monoclonal antibody (Ab). Pretreatment with an apoptosis signal-regulating kinase 1 (ASK1) inhibitor (thioredoxin), JNK inhibitor (SP600125), p38 inhibitor (SB203580), or AP-1 inhibitor (curcumin or tanshinone IIA) also blocked the potentiating action of TNF-α. Stimulation of cells with TNF-α enhanced ASK1, JNK, and p38 activation. Treatment of OASF with TNF-α also increased the accumulation of phosphorylated c-Jun in the nucleus, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the CCL2 promoter. TNF-α-mediated AP-1-luciferase activity and c-Jun binding to the AP-1 element were inhibited by TNFR1 Ab, thioredoxin, SP600125, and SB203580. Our results suggest that the interaction between TNF-α and TNFR1 increases CCL2 expression in human synovial fibroblasts via the ASK1, JNK/p38, c-Jun, and AP-1 signaling pathway.
Department of Neurosurgery, Taichung Veterans General Hospital, Taichung, Taiwan.
Hsi-Kai
HK
Tsou
Hsien-Te
HT
Chen
Chia-Hao
CH
Chang
Wan-Yu
WY
Yang
Chih-Hsin
CH
Tang
D000873:Anthracenes / Q000494:pharmacology; D000906:Antibodies / Q000494:pharmacology; D002061:Bursa, Synovial / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D003474:Curcumin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D008156:Luciferases; D048670:MAP Kinase Kinase 4 / Q000037:antagonists & inhibitors / Q000235:genetics; D048848:MAP Kinase Kinase Kinase 5 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology; D061251:Primary Cell Culture; D011725:Pyridines / Q000494:pharmacology; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000037:antagonists & inhibitors / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013879:Thioredoxins / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics
D000873:Anthracenes; D000906:Antibodies; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D007093:Imidazoles; D011725:Pyridines; D047888:Receptors, Tumor Necrosis Factor, Type I; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; C432165:pyrazolanthrone; D013879:Thioredoxins; D008156:Luciferases; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; C482858:MAP3K5 protein, human; D048670:MAP Kinase Kinase 4; D003474:Curcumin; C093642:SB 203580