1. Shear stress-induced Ets-1 modulates protease inhibitor expression in microvascular endothelial cells.
- Author
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Milkiewicz M, Uchida C, Gee E, Fudalewski T, and Haas TL
- Subjects
- Animals, Endothelial Cells drug effects, Endothelial Cells enzymology, Hemorheology, Hindlimb, Lasers, Male, Microcirculation metabolism, Microdissection methods, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3 metabolism, Phosphorylation, Plasminogen Activator Inhibitor 1 metabolism, Prazosin pharmacology, Proto-Oncogene Protein c-ets-1 genetics, 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, Endothelial Cells metabolism, Muscle, Skeletal blood supply, Protease Inhibitors metabolism, Proto-Oncogene Protein c-ets-1 metabolism
- 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., ((c) 2008 Wiley-Liss, Inc)
- Published
- 2008
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