title: Structural characterization of the mesangial cell type IV collagenase and enhanced expression in a model of immune complex-mediated glomerulonephritis.
abstract: Secretion of glomerular cell-derived matrix metalloproteinases (MMPs) and their specific inhibitors, TIMP-1,2, may play an important role in the turnover of the glomerular extracellular matrix under basal and pathologic conditions. A 66-68 kd MMP secreted by cultured mesangial cells (MC) with activity against Type IV collagen and gelatin was purified and shown by amino-acid sequence analysis to be identical with a Type IV collagenase/gelatinase secreted by certain transformed tumor cell lines. The expression of the mesangial MMP in vivo was limited within the kidney to a small subset of the intrinsic glomerular mesangial cell population. After induction of acute anti-Thy 1.1 glomerulonephritis, there was a large increment in the number of Type IV collagenase-secreting MC, temporally coincident with the development of mesangial hypercellularity. The expression of the MMP inhibitor protein, TIMP-1, was not changed over this period. Ultrastructural studies localized the mesangial MMP to areas of evolving mesangiolysis and at sites of glomerular basement membrane disruption. Enhanced expression of the mesangial cell-derived Type IV collagenase may contribute to the evolution of glomerular injury in this model of immune complex-mediated glomerulonephritis or may be involved in the extensive matrix remodeling process that accompanies this form of glomerular injury.
authors.affiliation: Department of Medicine, San Francisco Veteran's Administration Medical Center, University of California 94121.
authors.forename: D H
authors.initials: DH
authors.lastname: Lovett
authors.forename: R J
authors.initials: RJ
authors.lastname: Johnson
authors.forename: H P
authors.initials: HP
authors.lastname: Marti
authors.forename: J
authors.initials: J
authors.lastname: Martin
authors.forename: M
authors.initials: M
authors.lastname: Davies
authors.forename: W G
authors.initials: WG
authors.lastname: Couser
mesh_terms: D000595:Amino Acid Sequence; D000936:Antigen-Antibody Complex / Q000502:physiology*; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D005920:Glomerular Mesangium / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D005921:Glomerulonephritis / Q000201:enzymology* / Q000503:physiopathology; D006023:Glycoproteins / Q000032:analysis; D006651:Histocytochemistry; D006801:Humans; D020780:Matrix Metalloproteinase 9; D003012:Microbial Collagenase / Q000032:analysis* / Q000737:chemistry; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D019714:Tissue Inhibitor of Metalloproteinases
chemical_list: D000936:Antigen-Antibody Complex; D006023:Glycoproteins; D019714:Tissue Inhibitor of Metalloproteinases; D003012:Microbial Collagenase; D020780:Matrix Metalloproteinase 9