title: Matrix metalloproteinases 2 and 9 increase permeability of sheep pleura in vitro.
abstract: BACKGROUND
  Matrix metalloproteinases (MMPs) 2 and 9 are two gelatinase members which have been found elevated in exudative pleural effusions. In endothelial cells these MMPs increase paracellular permeability via the disruption of tight junction (TJ) proteins occludin and claudin. In the present study it was investigated if MMP2 and MMP9 alter permeability properties of the pleura tissue by degradation of TJ proteins in pleural mesothelium.
  
  
  RESULTS
  In the present study the transmesothelial resistance (RTM) of sheep pleura tissue was recorded in Ussing chambers after the addition of MMP2 or MMP9. Both enzymes reduced RTM of the pleura, implying an increase in pleural permeability. The localization and expression of TJ proteins, occludin and claudin-1, were assessed after incubation with MMPs by indirect immunofluorescence and western blot analysis. Our results revealed that incubation with MMPs did not alter neither proteins localization at cell periphery nor their expression.
  
  
  CONCLUSIONS
  MMP2 and MMP9 increase the permeability of sheep pleura and this finding suggests a role for MMPs in pleural fluid formation. Tight junction proteins remain intact after incubation with MMPs, contrary to previous studies which have shown TJ degradation by MMPs. Probably MMP2 and MMP9 augment pleural permeability via other mechanisms.
authors.affiliation: Department of Physiology, University of Thessaly Medical School, Larissa, Biopolis 41110, Greece. elaposto@med.uth.gr
authors.forename: Eleni
authors.initials: E
authors.lastname: Apostolidou
authors.forename: Efrosyni
authors.initials: E
authors.lastname: Paraskeva
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Gourgoulianis
authors.forename: Paschalis-Adam
authors.initials: PA
authors.lastname: Molyvdas
authors.forename: Chrissi
authors.initials: C
authors.lastname: Hatzoglou
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D020778:Matrix Metalloproteinase 2 / Q000494:pharmacology*; D020780:Matrix Metalloproteinase 9 / Q000494:pharmacology*; D010539:Permeability / Q000187:drug effects; D010994:Pleura / Q000187:drug effects* / Q000502:physiology*; D012756:Sheep
chemical_list: D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9