title: Modulation of matrix metalloproteinase and TIMP-1 expression by cytokines in human RPE cells.
abstract: OBJECTIVE
  The balance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) is crucial for homeostasis of ocular extracellular matrices. To assess altered MMP activity as a determinant in the migration of human retinal pigment epithelial (RPE) cells, expression characteristics of several MMPs and TIMP-1 in RPE cell cultures were investigated.
  
  
  METHODS
  Expression studies were performed with RT-PCR, ELISA, and immunofluorescence analysis. Secretion of MMP-2 was demonstrated by zymography. Migration of cytokine-stimulated RPE cells was evaluated with microporous membranes of permeable chambers.
  
  
  RESULTS
  MMP-1, -2, -3, and -9; MT2-MMP; and TIMP-1 were expressed in cultured RPE cells. MMP-2 was detected on the cell surface and in secreted inactive and active forms. TGF-beta(2), IL-1beta, and TNF-alpha enhanced secretion of MMP-1, -2, and -3. TGF-beta(2) also stimulated MT2-MMP cell surface expression and release of TIMP-1. The mRNA levels of MMP-1, -2, and -3 and TIMP-1 were markedly increased by TNF-alpha and TGF-beta(2). MMP-2 mRNA levels were also upregulated by PDGF-BB. Migration of RPE cells stimulated by TGF-beta(2) or PDGF-BB was inhibited in presence of a synthetic MMP inhibitor.
  
  
  CONCLUSIONS
  Proinflammatory cytokines and TGF-beta(2) play an important role in the upregulation of expression of MMP-1, -2, and -3 in RPE cells and account for a directional shift in the balance between MMPs and TIMPs. Facilitation of RPE cell migration stimulated by cytokines (i.e., TGF-beta(2) or PDGF-BB) in ocular diseases may be due to increased release of MMPs, in the presence of comparatively lower levels of their inhibitors.
authors.affiliation: University of Leipzig, Eye Hospital, Leipzig, Germany. eichwolf@rz.uni-leipzig.de
authors.forename: Wolfram
authors.initials: W
authors.lastname: Eichler
authors.forename: Ulrike
authors.initials: U
authors.lastname: Friedrichs
authors.forename: Alexander
authors.initials: A
authors.lastname: Thies
authors.forename: Corinna
authors.initials: C
authors.lastname: Tratz
authors.forename: Peter
authors.initials: P
authors.lastname: Wiedemann
mesh_terms: D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005109:Extracellular Matrix / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D018093:Gelatinases / Q000378:metabolism; D006801:Humans; D020782:Matrix Metalloproteinases / Q000096:biosynthesis* / Q000235:genetics; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D018093:Gelatinases; D020782:Matrix Metalloproteinases