Genetic Variants of the MMP-9 Gene in Patients with Acute Myocardial Infection - MMP-9 VARIANTS

Coordinating Institution: CRP Sante
Contracting Partner(s): Laboratory of Crystallography, Nancy (F) , Société Luxembourgeoise de Cardiologie , Centre Hospitalier de Luxembourg , Institut National de Chirurgie Cardiaque et de Cardiologie Interventionnelle - INCCI (L)
From: 01/09/2007
To: 31/08/2009
Budget: 397,500.00€
Contact(s): Wagner Daniel R.

Summary

Over the last decade, heart failure (HF) following myocardial infarction (MI) has become the leading cause of death in Luxembourg. Identification of patients at risk has therefore become a research priority for our laboratory as HF is potentially preventable. Previous experiments allowed for the identification of a new risk marker for HF after MI, the matrix metalloproteinase 9 (MMP9).

Sequencing of the whole mmp9 gene of patients with acute MI revealed the association between one single nucleotide polymorphism in the coding sequence of the mmp9 gene (called SNP*) and the development of HF. SNP* is located in PEX9, the MMP9 domain involved in interaction with the main natural MMP9 inhibitor, tissue inhibitor of matrix metalloproteinase 1 (TIMP1). This project aimed to determine whether SNP* could be used as a prognostic marker or a therapeutic target of HF.

Although not statistically significant, genotyping results of over 600 patients with acute MI using real-time PCR and TaqMan technology confirmed preliminary experiments indicating that SNP* is associated with a favorable outcome after MI. We next cloned and produced PEX9, PEX9* (PEX9 containing the SNP* mutation) and TIMP1 in bacteria to study the interactions PEX9-substrates and PEX9-TIMP1. We also cloned MMP9, MMP9* and TIMP1 in mammalian expression vectors, and expression of the proteins in MMP9-deficient cells was achieved to study the impact of the mutation on MMP9 expression at the cellular level. These molecular tools aided in the study of the impact of SNP* on MMP9 activity as well as on the migration and invasion properties of the cells. We have performed computational studies and modeling using molecular dynamics on PEX9, PEX9* and TIMP1.

An exciting finding was that SNP* enhanced the stability of the complex between PEX9 and TIMP1, which indicates that SNP* should decrease MMP9 activity, consistently with our observation that MMP9 adversely contributes to left ventricular remodeling and that SNP* is associated with favorable outcome after MI. This in silico approach allowed for the design of three potential peptide inhibitors of MMP9 that are currently under testing in our laboratory. Results obtained from this project have been patented. An international PCT application has been submitted on January 15th, 2008 (PCT/EP2008/00657): ‘Diagnostic marker and platform for drug design in myocardial infarction and heart failure”. We are now in the national phase of the application.