title: TNF-α induces matrix metalloproteinase-9-dependent soluble intercellular adhesion molecule-1 release via TRAF2-mediated MAPKs and NF-κB activation in osteoblast-like MC3T3-E1 cells.
abstract: BACKGROUND
  Matrix metalloproteinase-9 (MMP-9) has been shown to be induced by cytokines including TNF-α and may contribute to bone inflammatory diseases. However, the mechanisms underlying MMP-9 expression induced by TNF-α in MC3T3-E1 cells remain unclear.
  
  
  RESULTS
  We applied gelatin zymography, Western blot, RT-PCR, real-time PCR, selective pharmacological inhibitors of transcription (actinomycin D, Act.D), translation (cycloheximide, CHI), c-Src (PP1), MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), and NF-κB (Bay11-7082), respective siRNAs transfection, promoter assay, immunofluorescence staining, and ELISA to investigate the MMP-9 expression and soluble ICAM-1 (sICAM-1) release induced by TNF-α in MC3T3-E1 cells. Here we demonstrated that TNF-α-induced MMP-9 expression was attenuated by Act.D, CHI, PP1, U0126, SB202190, SP600125, and Bay11-7082, and by the transfection with siRNAs for ERK2, p38 MAPK, and JNK2. TNF-α-stimulated TNFR1, TRAF2, and c-Src complex formation was revealed by immunoprecipitation and Western blot. Furthermore, TNF-α-stimulated NF-κB phosphorylation and translocation were blocked by Bay11-7082, but not by PP1, U0126, SB202190, or SP600125. TNF-α time-dependently induced MMP-9 promoter activity which was also inhibited by PP1, U0126, SB202190, SP600125, or Bay11-7082. Up-regulation of MMP-9 was associated with the release of sICAM-1 into the cultured medium, which was attenuated by the pretreatment with MMP-2/9i, an MMP-9 inhibitor.
  
  
  CONCLUSIONS
  In this study, we demonstrated that TNF-α up-regulates MMP-9 expression via c-Src, MAPKs, and NF-κB pathways. In addition, TNF-α-induced MMP-9 expression may contribute to the production of sICAM-1 by MC3T3-E1 cells. The interplay between MMP-9 expression and sICAM-1 release may exert an important role in the regulation of bone inflammatory diseases.
authors: Chia-Lan
authors: CL
authors: Tsai
authors: Wei-Chung
authors: WC
authors: Chen
authors: Hsi-Lung
authors: HL
authors: Hsieh
authors: Pei-Ling
authors: PL
authors: Chi
authors: Li-Der
authors: LD
authors: Hsiao
authors: Department of Physiology and Pharmacology and Health Ageing Research Center, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan. chuenmao@mail.cgu.edu.tw.
authors: Chuen-Mao
authors: CM
authors: Yang
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000187:drug effects; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D016328:NF-kappa B / Q000378:metabolism; D010000:Osteitis / Q000378:metabolism / Q000473:pathology; D010006:Osteoblasts / Q000378:metabolism; D010766:Phosphorylation; D015398:Signal Transduction; D047992:TNF Receptor-Associated Factor 2 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D016328:NF-kappa B; D047992:TNF Receptor-Associated Factor 2; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048051:p38 Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D020780:Matrix Metalloproteinase 9