title: Differential effects of mechanical and biological stimuli on matrix metalloproteinase promoter activation in the thoracic aorta.
abstract: BACKGROUND
  The effect of multiple integrated stimuli on vascular wall expression of matrix metalloproteinases (MMPs) remains unknown. Accordingly, this study examined the influence of the vasoactive peptide angiotensin II (Ang II) on wall tension-induced promoter activation of MMP-2, MMP-9, and membrane type-1 MMP (MT1-MMP).
  
  
  RESULTS
  Thoracic aortic rings harvested from transgenic reporter mice containing the MMP-2, MMP-9, or MT1-MMP promoter sequence fused to a reporter gene were subjected to 3 hours of wall tension at 70, 85, or 100 mm Hg, with or without 100 nM Ang II. Total RNA was harvested from the aortic rings, and reporter gene transcripts were quantified by quantitative real-time polymerase chain reaction to measure MMP promoter activity. MT1-MMP promoter activity was increased at both 85 and 100 mm Hg, compared with baseline tension of 70 mm Hg, whereas treatment with Ang II stimulated MT1-MMP promoter activity to the same degree at all tension levels (P<0.05). Elevated tension and Ang II displayed a potential synergistic enhancement of MMP-2 promoter activation at 85 and 100 mm Hg, whereas the same stimuli caused a decrease in MMP-9 promoter activity (P<0.05) at 100 mm Hg.
  
  
  CONCLUSIONS
  This study demonstrated that exposure to a relevant biological stimulus (Ang II) in the presence of elevated tension modulated MMP promoter activation. Furthermore, these data suggest that a mechanical-molecular set point exists for the induction of MMP promoter activation and that this set point can be adjusted up or down by a secondary biological stimulus. Together, these results may have significant clinical implications toward the regulation of hypertensive vascular remodeling.
authors.affiliation: Department of Surgery, Medical University of South Carolina, Charleston, 29425, USA.
authors.forename: Jean Marie
authors.initials: JM
authors.lastname: Ruddy
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Jones
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stroud
authors.forename: Rupak
authors.initials: R
authors.lastname: Mukherjee
authors.forename: Francis G
authors.initials: FG
authors.lastname: Spinale
authors.forename: John S
authors.initials: JS
authors.lastname: Ikonomidis
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000201:enzymology*; D005260:Female; D008297:Male; D053511:Matrix Metalloproteinase 14 / Q000235:genetics*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics*; D051379:Mice; D011401:Promoter Regions, Genetic; D044140:Receptor, Angiotensin, Type 1 / Q000502:physiology; D015398:Signal Transduction; D013314:Stress, Mechanical
chemical_list: C507096:Mmp14 protein, mouse; D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D053511:Matrix Metalloproteinase 14