Phosphorylation status of matrix metalloproteinase 2 in myocardial ischaemia–reperfusion injury
- Meltem Sariahmetoglu1,2,
- Monika Skrzypiec-Spring3,
- Nermeen Youssef1,
- Anna Laura B Jacob-Ferreira1,
- Jolanta Sawicka4,
- Charles Holmes2,
- Grzegorz Sawicki4,5,
- Richard Schulz1
- 1Departments of Pediatrics and Pharmacology, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
- 2Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- 3Department of Pharmacology, Medical University of Wroclaw, Wroclaw, Poland
- 4Department of Pharmacology, University of Saskatchewan, Saskatoon, Canada
- 5Department of Clinical Chemistry, Medical University of Wroclaw, Wroclaw, Poland
- Correspondence to Dr Richard Schulz, Cardiovascular Research Centre, 462 Heritage Medical Research Center, University of Alberta, Edmonton, Alberta T6G 2S2, Canada;
- Accepted 6 February 2012
- Published Online First 7 March 2012
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.
Design In-vitro heart function and biochemical research study.
Setting University basic science laboratory.
Interventions 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.
Main Outcome Measures 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.
- Cardiac function
- circadian rhythm
- contractile proteins
- free radicals
- matrix metalloproteinases
- myocardial dysfunction
- myocardial ischaemia and infarction (IHD)
- oxidative stress
Funding This project was funded by a grant from the Canadian Institutes of Health Research (to RS, MOP 77526). The study sponsors had no role in the collection, analysis and interpretation of data, in writing of the report, nor in the decision to submit the paper for publication.
Competing interests None.
Ethics approval This investigation conforms to the guide to the care and use of experimental animals published by the Canadian Council on Animal Care.
Provenance and peer review Not commissioned; externally peer reviewed.