title: Increase of TNFα-stimulated osteoarthritic chondrocytes apoptosis and decrease of matrix metalloproteinases 9 by NF-κB inhibition.
abstract: OBJECTIVE
  To investigate the in vitro effect of caffeic acid phenethyl ester (CAPE), a NF-κB inhibitor, on the apoptosis of osteoarthritic (OA) chondrocytes and on the regulation of the gelatinases matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9).
  
  
  METHODS
  Annexin V-FITC/propidium iodide (PI) labeling and western blotting were used to observe and determine the apoptosis in TNFα-stimulated primary cultured osteoarthritic chondrocytes. Also, gelatin zymography was applied to examine MMP-2 and MMP-9 activities in supernatants.
  
  
  RESULTS
  It was confirmed by both flow cytometry and western blotting that chondrocytes from OA patients have an apoptotic background. Use of CAPE in combination with 10 ng/mL of TNFα for 24 h facilitated the apoptosis. MMP-9 in the supernatant could be autoactivated (from proMMP-9 to active MMP-9), and the physiologic calcium concentration (2.5 mmol/L) could delay the autoactivation of MMP-9. The activities of MMP-2 and MMP-9 in the fresh supernatant increased significantly in response to stimulation by 10 ng/mL of TNFα for 24 h. The stimulatory effect of TNFα just on proMMP-9 was counteracted significantly by CAPE.
  
  
  CONCLUSIONS
  NF-κB could prevent chondrocytes apoptosis though its activation was attributed to the increase of proMMP-9 activity induced by TNFα (a pro-apoptotic factor). Therefore, therapeutic NF-κB inhibitor was a 'double-edged swords' to the apoptosis of chondrocytes and the secretion of MMP-9.
authors.affiliation: Department of general surgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: De Ling
authors.initials: de L
authors.lastname: Li
authors.forename: Xin Bo
authors.initials: XB
authors.lastname: Zhang
authors.forename: Yuan Hui
authors.initials: YH
authors.lastname: Duan
authors.forename: Zhi Hong
authors.initials: ZH
authors.lastname: Wu
authors.forename: Dong Sheng
authors.initials: DS
authors.lastname: Hao
authors.forename: Bao Sheng
authors.initials: BS
authors.lastname: Chen
authors.forename: Gui Xing
authors.initials: GX
authors.lastname: Qiu
mesh_terms: D000368:Aged; D017209:Apoptosis / Q000187:drug effects*; D002109:Caffeic Acids / Q000494:pharmacology* / Q000627:therapeutic use; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D005260:Female; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D010003:Osteoarthritis / Q000188:drug therapy / Q000201:enzymology; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D002109:Caffeic Acids; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol; D002118:Calcium
keywords: Apoptosis; Chondrocytes; Gelatinase; NF-κB; Tumor necrosis factor α