title: Stimulation of matrix metalloproteinases by tumor necrosis factor-α in human pulp cell cultures.
abstract: BACKGROUND
  The purpose of this study was to investigate whether in vitro stimulation of pulp cells leads to increased secretion of matrix metalloproteinases (MMPs) and, if so, to identify which MMPs are affected.
  
  
  METHODS
  Cells cultured from dental pulp were stimulated with tumor necrosis factor-α (TNF-α) (10 ng/mL) for 24 hours, and lysates were analyzed with an antibody array (Bio-Rad Laboratories, Hercules, CA). The mRNA and protein levels of MMP-3, -10, and -13 were measured by real-time polymerase chain reaction (real-time PCR), enzyme-linked immunosorbent assay (ELISA), Western blot analysis, and zymography. In addition, tumor necrosis factor receptors in the pulp cells were assayed by flow cytometry. The ELISA and real-time PCR results were analyzed by paired t tests.
  
  
  RESULTS
  The expression of MMP-3, -10, and -13 was up-regulated in the pulp cells after 24 hours of stimulation with TNF-α (10 ng/mL) as seen in the antibody array, real-time PCR, and ELISA results, but MMP-10 was not detected by Western blotting or casein zymography. Flow cytometry analysis showed that the majority of the pulp cells expressed tumor necrosis factor receptor 1.
  
  
  CONCLUSIONS
  In regions of inflammation, TNF-α may initiate the degradation of dental connective tissue by activating MMP-3 and MMP-13. These proteins may play an important pathologic role in the inflammation of dental pulp.
authors.affiliation: Department of Conservative Dentistry, St Paul's Hospital, Seoul, Korea.
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Rhim
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Ahn
authors.forename: Ji-Yoen
authors.initials: JY
authors.lastname: Kim
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Kim
authors.forename: Hyeon-Woo
authors.initials: HW
authors.lastname: Lee
authors.forename: Eun-Cheol
authors.initials: EC
authors.lastname: Kim
authors.forename: Kun-Young
authors.initials: KY
authors.lastname: Kim
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Park
mesh_terms: D018929:Cell Culture Techniques; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D053506:Matrix Metalloproteinase 10 / Q000032:analysis / Q000187:drug effects; D053509:Matrix Metalloproteinase 13 / Q000032:analysis / Q000187:drug effects; D019278:Matrix Metalloproteinase 3 / Q000032:analysis / Q000187:drug effects; D020782:Matrix Metalloproteinases / Q000032:analysis / Q000187:drug effects*; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000032:analysis; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation
chemical_list: D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D020782:Matrix Metalloproteinases; C511768:MMP3 protein, human; D019278:Matrix Metalloproteinase 3; C511770:MMP10 protein, human; D053506:Matrix Metalloproteinase 10