title: Phosphorylation status of matrix metalloproteinase 2 in myocardial ischaemia-reperfusion injury.
abstract: OBJECTIVE
  To investigate whether alterations in the phosphorylation status of matrix metalloproteinase 2 (MMP-2) in the heart may be protective in the setting of ischaemia-reperfusion (IR) injury.
  
  
  METHODS
  In-vitro heart function and biochemical research study.
  
  
  METHODS
  University basic science laboratory.
  
  
  METHODS
  Male Sprague-Dawley rats, weighing 250-350 g. Isolated rat hearts were perfused at constant pressure either aerobically for 75 min or subjected to 20 min of global, no-flow ischaemia followed by 30 min of reperfusion.
  
  
  METHODS
  Heart mechanical function, MMP-2 activity and troponin I levels.
  
  
  RESULTS
  The serine/threonine phosphatase inhibitor okadaic acid (OA) improved the recovery of mechanical function compared with control IR hearts and prevented the loss of troponin I. OA significantly reduced protein phosphatase 2A, but not protein phosphatase 1, activity in perfused hearts. IR stimulated the activation and release of MMP-2 into the coronary effluent in the first 2 min of reperfusion. This was accompanied by a decrease in the remaining activity and protein level of MMP-2 in heart tissue determined at the end of the reperfusion. OA did not alter the IR-stimulated release of MMP-2 into the coronary effluent, but reduced the decrease in MMP-2 in reperfused hearts. The immunoprecipitation of heart homogenates using anti-phosphoserine antibody showed that MMP-2 is phosphorylated. The dephosphorylation of MMP-2 by alkaline phosphatase treatment of homogenates prepared from IR hearts treated with OA significantly increased MMP-2 activity.
  
  
  CONCLUSIONS
  These results suggest that the phosphorylation status of MMP-2 is important in its contribution to myocardial IR injury.
authors.affiliation: Department of Pediatrics, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Meltem
authors.initials: M
authors.lastname: Sariahmetoglu
authors.forename: Monika
authors.initials: M
authors.lastname: Skrzypiec-Spring
authors.forename: Nermeen
authors.initials: N
authors.lastname: Youssef
authors.forename: Anna Laura B
authors.initials: AL
authors.lastname: Jacob-Ferreira
authors.forename: Jolanta
authors.initials: J
authors.lastname: Sawicka
authors.forename: Charles
authors.initials: C
authors.lastname: Holmes
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Sawicki
authors.forename: Richard
authors.initials: R
authors.lastname: Schulz
mesh_terms: D000469:Alkaline Phosphatase / Q000494:pharmacology; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D006321:Heart / Q000187:drug effects; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000201:enzymology* / Q000517:prevention & control; D009206:Myocardium / Q000201:enzymology; D019319:Okadaic Acid / Q000494:pharmacology / Q000627:therapeutic use; D010766:Phosphorylation / Q000187:drug effects; D054645:Protein Phosphatase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D019210:Troponin I / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D019210:Troponin I; D019319:Okadaic Acid; D000469:Alkaline Phosphatase; D054645:Protein Phosphatase 1; D054648:Protein Phosphatase 2; D020778:Matrix Metalloproteinase 2