Shear stress-induced Ets-1 modulates protease inhibitor expression in microvascular endothelial cells

J Cell Physiol. 2008 Nov;217(2):502-10. doi: 10.1002/jcp.21526.

Abstract

Elevated shear stress within the skeletal muscle microvasculature is implicated in the induction of a longitudinal splitting form of angiogenesis, which is characterized by the lack of basement membrane breakage. We investigated whether the transcriptional regulator, Ets-1, is responsive to changes in hemodynamic forces and if so, whether Ets-1 controls microvascular endothelial cell integrity by inducing the expression of inhibitors of matrix degrading proteases. Rats were treated with prazosin for 2, 4, and 7 days to increase in microvascular shear stress in hindlimb skeletal muscles. In complimentary in vitro experiments, rat microvascular skeletal muscle endothelial cells were exposed to laminar shear stress (15 dyne/cm(2)) for 0.5, 2, and 24 h. TaqMan PCR analysis of laser microdissected capillaries isolated from EDL muscles demonstrated transient (after 2 days) induction of Ets-1 gene expression. In cultured cells, a transient up-regulation of Ets-1 mRNA was observed after 2 h shear stimulation, accompanied by increased phosphorylation of Ets-1 and enhanced Ets-1 DNA binding activity. This response was modulated by ERK1/2 and p38 MAP kinases, but was not dependent on NOS or COX-2 activity. PAI-1, TIMP-1 and TIMP-3 mRNA were elevated significantly in prazosin treated EDL, and in response to shear stimulation in vitro. In cultured endothelial cells, Ets-1 RNA interference abolished the shear-induced increases in Ets-1, PAI-1, TIMP-1, and TIMP-3 mRNA expression. These results suggest that enhanced laminar shear stress may act to preserve the integrity of microvascular walls in part through Ets-1-dependent induction of protease inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Endothelial Cells / drug effects
  • Endothelial Cells / enzymology
  • Endothelial Cells / metabolism*
  • Hemorheology
  • Hindlimb
  • Lasers
  • Male
  • Microcirculation / metabolism
  • Microdissection / methods
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Muscle, Skeletal / blood supply*
  • Phosphorylation
  • Plasminogen Activator Inhibitor 1 / metabolism
  • Prazosin / pharmacology
  • Protease Inhibitors / metabolism*
  • Proto-Oncogene Protein c-ets-1 / genetics
  • Proto-Oncogene Protein c-ets-1 / metabolism*
  • RNA Interference
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Reverse Transcriptase Polymerase Chain Reaction
  • Stress, Mechanical
  • Time Factors
  • Tissue Inhibitor of Metalloproteinase-1 / metabolism
  • Tissue Inhibitor of Metalloproteinase-3 / metabolism
  • Up-Regulation
  • Vasodilator Agents / pharmacology
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Ets1 protein, rat
  • Plasminogen Activator Inhibitor 1
  • Protease Inhibitors
  • Proto-Oncogene Protein c-ets-1
  • RNA, Messenger
  • RNA, Small Interfering
  • Tissue Inhibitor of Metalloproteinase-1
  • Tissue Inhibitor of Metalloproteinase-3
  • Vasodilator Agents
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • p38 Mitogen-Activated Protein Kinases
  • Prazosin