Early matrix metalloproteinase-12 inhibition worsens post-myocardial infarction cardiac dysfunction by delaying inflammation resolution

• Published in: International journal of cardiology Vol. 185; pp. 198 - 208
• Main Authors: Iyer, Rugmani Padmanabhan, Patterson, Nicolle L, Zouein, Fouad A, Ma, Yonggang, Dive, Vincent, de Castro Brás, Lisandra E, Lindsey, Merry L
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ireland Ltd 15.04.2015
• Subjects: Animals; Apoptosis; Cardiovascular; CD44; Disease Models, Animal; Gene Expression Regulation; Immunoblotting; Immunohistochemistry; Inflammation - enzymology; Inflammation - genetics; LV remodeling; Male; Matrix Metalloproteinase 12 - biosynthesis; Matrix Metalloproteinase 12 - drug effects; Matrix Metalloproteinase 12 - genetics; Matrix Metalloproteinase Inhibitors - pharmacology; Mice; Mice, Inbred C57BL; MMP-12; Myocardial Infarction - complications; Myocardial Infarction - drug therapy; Myocardial Infarction - enzymology; Neutrophil; Proteomics; Real-Time Polymerase Chain Reaction; RNA - genetics; Ventricular Dysfunction, Left - enzymology; Ventricular Dysfunction, Left - etiology; Ventricular Dysfunction, Left - genetics; Ventricular Function, Left - drug effects; Ventricular Function, Left - physiology; Ventricular Remodeling - physiology; MMP-12; LV remodeling; Neutrophil; CD44; Proteomics; Apoptosis
• ISSN: 0167-5273; 1874-1754
• DOI: 10.1016/j.ijcard.2015.03.054

Abstract Rationale Matrix metalloproteinases (MMPs) regulate remodeling of the left ventricle (LV) post-myocardial infarction (MI). MMP-12 has potent macrophage-dependent remodeling properties in the atherosclerotic plaque; however, post-MI roles have not been examined. Objective The goal was to determine MMP-12 post-MI mechanisms. Methods and results Male C57BL/6J mice (3–6 months old) were subjected to left coronary artery ligation. Saline or the RXP 470.1 MMP-12 inhibitor (MMP-12i; 0.5 mg/kg/day) was delivered by osmotic mini-pump beginning 3 h post-MI, and mice were sacrificed at day (d)1, 3, 5 or 7 post-MI and compared to d0 controls (mice without MI; n = 6–12/group/time). MMP-12 expression increased early post-MI, and contrary to expected, neutrophils were a surprising early cellular source for MMP-12. MMP-12i reduced MMP-12 activity 33 ± 1% at d1 post-MI. Despite similar infarct areas and survival rates, MMP-12i led to greater LV dilation and worsened LV function. At d7 post-MI, MMP-12i prolonged pro-inflammatory cytokine upregulation ( IL1r1 , IL6ra , IL11 , and Cxcr5 ) and decreased CD44 (both gene and protein levels). Hyaluronan (HA), a CD44 ligand, was elevated at d1 and d7 post-MI with MMP12i, as a result of decreased fragmentation. Because CD44-HA regulates neutrophil removal, apoptosis markers were evaluated. Caspase 3 increased, while cleaved caspase 3 levels decreased in MMP-12i group at d7 post-MI, indicating reduced neutrophil apoptosis. In isolated neutrophils, active MMP-12 directly stimulated CD44, caspase 3, and caspase 8 expression. Conclusion Our results reveal a novel protective mechanism for MMP-12 in neutrophil biology. Post-MI, MMP-12i impaired CD44–HA interactions to suppress neutrophil apoptosis and prolong inflammation, which worsened LV function.