Heparin selectively inhibits synthesis of tissue type plasminogen activator and matrix deposition of plasminogen activator inhibitor 1 by human mesangial cells

Lab Invest. 1994 Dec;71(6):828-37.

Abstract

Background: Mesangial changes in a variety of pathologic conditions involve mesangial cell proliferation and mesangial matrix remodelling. Heparin has been shown to prevent these processes in vivo. In vitro, heparin interferes with cell growth, proto-oncogene expression, synthesis of specific proteins, and extracellular matrix composition. In some cell types, it seems to interact with intracellular protein kinase C-dependent pathways. The effect of heparin on the mesangial plasminogen activating system (tissue type plasminogen activator, t-PA, and plasminogen activator inhibitor type 1, PAI-1), which is thought to be involved in matrix remodelling, has not been previously reported.

Experimental design: Cultured human mesangial cells were stimulated by 10% fetal calf serum (FCS) or 16 nM phorbol myristate acetate (PMA) in the presence or absence of anticoagulant or nonanticoagulant heparins. Cell proliferation, synthesis of t-PA and PAI-1, cell morphology, and PAI-1 matrix deposition were studied using cell counting, [3H]thymidine incorporation, specific t-PA and PAI-1 enzyme-linked immunosorbent assay, Northern blot analysis, light microscopy, immunofluorescence and immunogold silver staining with combined bright-field and epipolarization microscopy.

Results: Heparin partially inhibited FCS-stimulated cell growth but not PMA-induced thymidine incorporation. FCS and PMA stimulated t-PA (p < 0.05 and p < 0.01, respectively) and PAI-1 synthesis (p < 0.05 and p < 0.01 respectively). Heparin selectively and partially inhibited FCS-stimulated t-PA, but not PAI-1 synthesis. It has no effect on PMA-stimulated t-PA or PAI-1 synthesis but prevented cell shape-changes induced by PMA, suggesting that heparin inhibits some but not all protein kinase C (PKC)-dependent effects and that heparin block in t-PA synthesis is distal to PKC activation. Heparin decreased PAI-1 matrix accumulation. Similar distal to PKC activation. Heparin decreased PAI-1 matrix accumulation. Similar results were observed with anticoagulant and nonanticoagulant heparin fragments.

Conclusions: In human mesangial cells, anticoagulant and nonanticoagulant heparin exert an antiproliferative effect and may prevent mesangial matrix changes by decreasing FCS-stimulated t-PA synthesis and PAI-1 deposition in the matrix. Heparin is able to inhibit PKC-dependent cell shape changes but not PKC-dependent t-PA or PAI-1 synthesis. It also inhibits PKC-independent cell proliferation and t-PA synthesis. These results suggest multiple intracellular sites of action for heparin, unrelated or distal to PKC activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Northern
  • Cell Division / drug effects
  • Cells, Cultured
  • Enzyme-Linked Immunosorbent Assay
  • Glomerular Mesangium / cytology
  • Glomerular Mesangium / drug effects*
  • Heparin / chemistry
  • Heparin / pharmacology*
  • Heparitin Sulfate / pharmacology
  • Humans
  • Immunohistochemistry
  • Microscopy, Polarization
  • Plasminogen Activator Inhibitor 1 / biosynthesis*
  • Plasminogen Activator Inhibitor 1 / immunology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Tissue Plasminogen Activator / biosynthesis*

Substances

  • Plasminogen Activator Inhibitor 1
  • Heparin
  • Heparitin Sulfate
  • Tissue Plasminogen Activator
  • Tetradecanoylphorbol Acetate