title: Degradation of glomerular basement membrane by purified mammalian metalloproteinases.
abstract: Neutral metalloproteinases degrade components of the extracellular matrix, including collagen types I-V, fibronectin, laminin and proteoglycan. However, their ability to degrade intact glomerular basement membrane (GBM) has not previously been investigated. Incubation of [3H]GBM (50,000 c.p.m.; pH 7.5; 24 h at 37 degrees C) with purified gelatinase or stromelysin (2 units) resulted in significant GBM degradation: gelatinase, 46 +/- 2.2; stromelysin, 59 +/- 5.8 (means +/- S.E.M.; percentage release of non-sedimentable radioactivity; n = 4). In contrast, 2 units of collagenase released only 5.6 +/- 0.52% (n = 3) of the [3H]GBM radioactivity compared with 2.0 +/- 0.15% (n = 7) released from [3H]GBM incubated alone. Sephadex G-200 gel chromatography of supernatants obtained from incubations of [3H]GBM with either gelatinase or stromelysin confirmed the ability of these enzymes to degrade GBM and revealed both high-(800,000) and relatively low-(less than 20,000) Mr degradation products for both enzymes. GBM degradation by gelatinase and stromelysin was dose-dependent (range 0.02-2.0 units), near maximal between pH 6.0 and 8.6, and was completely inhibited (greater than 95%) by 2 mM-o-phenanthroline. Collagenase (2 units) did not enhance the degradation of GBM by either gelatinase (0.02 or 0.2 unit) or stromelysin (0.02 or 0.2 unit). Our results indicate that metalloproteinase-mediated GBM degradation by neutrophils and glomeruli may be attributable to gelatinase (neutrophils) and/or stromelysin (glomeruli) and suggest an important role for these proteinases in glomerular pathophysiology.
authors.affiliation: Department of Biochemistry, Tulane Medical School, New Orleans, LA 70112.
authors.forename: W H
authors.initials: WH
authors.lastname: Baricos
authors.forename: G
authors.initials: G
authors.lastname: Murphy
authors.forename: Y W
authors.initials: YW
authors.lastname: Zhou
authors.forename: H H
authors.initials: HH
authors.lastname: Nguyen
authors.forename: S V
authors.initials: SV
authors.lastname: Shah
mesh_terms: D000818:Animals; D001485:Basement Membrane / Q000187:drug effects; D002417:Cattle; D002850:Chromatography, Gel; D018093:Gelatinases; D006863:Hydrogen-Ion Concentration; D007678:Kidney Glomerulus / Q000187:drug effects*; D019278:Matrix Metalloproteinase 3; D008666:Metalloendopeptidases / Q000494:pharmacology*; D003012:Microbial Collagenase / Q000494:pharmacology; D010434:Pepsin A / Q000494:pharmacology*
chemical_list: D010434:Pepsin A; D018093:Gelatinases; D008666:Metalloendopeptidases; D019278:Matrix Metalloproteinase 3; D003012:Microbial Collagenase