title: Expression of matrix metalloproteinases and their inhibitors in human trabecular meshwork cells.
abstract: OBJECTIVE
  Matrix metalloproteinases (MMPs) are involved in trabecular meshwork (TM) extracellular matrix metabolism and have been shown to increase aqueous outflow facility. The purpose of this study was to characterize effects of cytokines, a phorbol ester, and prostanoids on the expression of MMP-1, -2, -3, and -9 and tissue inhibitors of metalloproteinases (TIMP)-1 and -2 in cultured human TM cells.
  
  
  METHODS
  Five human TM cell strains were treated with selected compounds. Levels of proMMPs and TIMPs in cell media were quantified by ELISA. MMP-3 activity was assayed by casein zymography.
  
  
  RESULTS
  All human TM cell strains produced detectable basal amounts of proMMPs and TIMPs. 12-O-tetradecanoyl-phorbol-13-acetate was effective in increasing the levels of proMMP-1, -3, and -9 and TIMP-1. Its effect on proMMP-1 was concentration-dependent with an EC(50) of 2 to 3 nM. Interleukin (IL)-1alpha did not affect levels of proMMP-1 and -2 or the TIMPs, but was most efficacious in increasing proMMP-3 production with an EC(50) of 0.5 ng/mL. The IL-1alpha-induced upregulation of proMMP-3 correlated with an increase in MMP-3 activity. Tumor necrosis factor-alpha activated proMMP-3 production in some but not all cell strains. Platelet-derived growth factor-BB was generally ineffective in modulating MMP and TIMP levels. Prostaglandins E(2) and F(2alpha) at 10 micro M did not affect levels of proMMP-1 or -3.
  
  
  CONCLUSIONS
  The expression of the different MMPs and TIMPs in human TM cells was independently regulated. Production of MMP-3 was maximally activated by IL-1alpha. The IL-1alpha-stimulated expression of MMP-3 provides a probable mechanism for IL-1alpha-enhanced aqueous outflow.
authors.affiliation: Alcon Research, Ltd., Fort Worth, Texas 76134, USA. iok-hou.pang@alconlabs.com
authors.forename: Iok-Hou
authors.initials: IH
authors.lastname: Pang
authors.forename: Peggy E
authors.initials: PE
authors.lastname: Hellberg
authors.forename: Debra L
authors.initials: DL
authors.lastname: Fleenor
authors.forename: Nasreen
authors.initials: N
authors.lastname: Jacobson
authors.forename: Abbot F
authors.initials: AF
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D000077214:Becaplermin; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007223:Infant; D007375:Interleukin-1 / Q000494:pharmacology; D020782:Matrix Metalloproteinases / Q000096:biosynthesis*; D008875:Middle Aged; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis*; D014129:Trabecular Meshwork / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D007375:Interleukin-1; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D019715:Tissue Inhibitor of Metalloproteinase-1; D014409:Tumor Necrosis Factor-alpha; D019716:Tissue Inhibitor of Metalloproteinase-2; D000077214:Becaplermin; D020782:Matrix Metalloproteinases; D013755:Tetradecanoylphorbol Acetate