Integration of non-SMAD and SMAD signaling in TGF-beta1-induced plasminogen activator inhibitor type-1 gene expression in vascular smooth muscle cells

Thromb Haemost. 2008 Dec;100(6):976-83.

Abstract

Overexpression of plasminogen activator inhibitor-1 (SERPINE1, PAI-1), the major physiological inhibitor of pericellular plasmin generation, is a significant causative factor in the progression of vascular disorders (e.g. arteriosclerosis, thrombosis, perivascular fibrosis) as well as a biomarker and a predictor of cardiovascular-disease associated mortality. PAI-1 is a temporal/spatial regulator of pericellular proteolysis and ECM accumulation impacting, thereby, vascular remodeling, smooth muscle cell migration, proliferation and apoptosis. Within the specific context of TGF-beta1-initiated vascular fibrosis and neointima formation, PAI-1 is a member of the most prominently expressed subset of TGF-beta1-induced transcripts. Recent findings implicate EGFR/pp60c-src-->MEK/ERK1/2 and Rho/ROCK-->SMAD2/3 signaling in TGF-beta1-stimulated PAI-1 expression in vascular smooth muscle cells. The EGFR is a direct upstream regulator of MEK/ERK1/2 while Rho/ROCK modulate both the duration of SMAD2/3 phosphorylation and nuclear accumulation. E-box motifs (CACGTG) in the PE1/PE2 promoter regions of the human PAI-1 gene, moreover, are platforms for a MAP kinase-directed USF subtype switch (USF-1-->USF-2) in response to growth factor addition suggesting that the EGFR-->MEK/ERK axis impacts PAI-1 expression, at least partly, through USF-dependent transcriptional controls. This paper reviews recent data suggesting the essential cooperativity among the EGFR-->MAP kinase cascade, the Rho/ROCK pathway and SMADs in TGF-beta1-initiated PAI-1 expression. The continued clarification of mechanistic controls on PAI-1 transcription may lead to new targeted therapies and clinically-relevant options for the treatment of vascular diseases in which PAI-1 dysregulation is a major underlying pathogenic feature.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Animals
  • E-Box Elements
  • ErbB Receptors / metabolism
  • Gene Expression Regulation
  • Humans
  • Mitogen-Activated Protein Kinases / metabolism
  • Muscle, Smooth, Vascular / enzymology
  • Muscle, Smooth, Vascular / metabolism*
  • Myocytes, Smooth Muscle / enzymology
  • Myocytes, Smooth Muscle / metabolism*
  • Phosphorylation
  • Plasminogen Activator Inhibitor 1 / genetics
  • Plasminogen Activator Inhibitor 1 / metabolism*
  • Promoter Regions, Genetic
  • Signal Transduction*
  • Smad Proteins / metabolism*
  • Transcription, Genetic
  • Transforming Growth Factor beta1 / metabolism*
  • Vascular Diseases / enzymology
  • Vascular Diseases / genetics
  • Vascular Diseases / metabolism*
  • rho GTP-Binding Proteins / metabolism
  • rho-Associated Kinases / metabolism

Substances

  • Plasminogen Activator Inhibitor 1
  • Smad Proteins
  • Transforming Growth Factor beta1
  • ErbB Receptors
  • rho-Associated Kinases
  • Mitogen-Activated Protein Kinases
  • rho GTP-Binding Proteins