Deficiency in TIMP-3 increases cardiac rupture and mortality post-myocardial infarction via EGFR signaling: beneficial effects of cetuximab.
Cardiac rupture is a fatal complication of myocardial infarction (MI); however, its underlying molecular mechanisms are not fully understood. This study investigated the role of tissue inhibitor of metalloproteinase-3 (TIMP-3)/matrix metalloproteinase (MMP)/epidermal growth factor (EGF)/transforming growth factor (TGF)-β1 pathway in infarct healing and effects of cetuximab on cardiac rupture after MI. Induction of MI was achieved by left coronary artery ligation in wild-type (WT) and TIMP-3(-/-) mice. TIMP-3 deficiency resulted in a fourfold increase in cardiac rupture and 50% decrease in survival after MI. Hydroxyproline content, collagen synthesis and myofibroblast cell number in the infarct region, and the force required to induce rupture of the infarct scar were significantly decreased, while MMP activity was increased in TIMP-3(-/-) mice. EGF proteins were increased by threefold in TIMP-3(-/-) mice following MI, while TGF-β1 mRNA levels were decreased by 68%. Cell proliferation of cultured adult cardiac myofibroblasts was significantly decreased in TIMP-3(-/-) compared to WT myofibroblasts. EGF treatment significantly decreased collagen synthesis and TGF-β1 expression. Conversely, TGF-β1 treatment increased collagen synthesis in cardiac myofibroblasts. Treatment with cetuximab significantly decreased the incidence of cardiac rupture and improved survival post-MI in TIMP-3(-/-) mice. We conclude that deficiency in TIMP-3 increases cardiac rupture post-MI via EGF/epidermal growth factor receptor (EGFR) signaling which downregulates TGF-β1 expression and collagen synthesis. Inhibition of EGFR by cetuximab protects against cardiac rupture and improves survival post-MI.
Department of Physiology and Pharmacology, University of Western Ontario, London, Canada.
Lamis
L
Hammoud
Xiangru
X
Lu
Ming
M
Lei
Qingping
Q
Feng
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000068818:Cetuximab; D003094:Collagen / Q000096:biosynthesis; D066246:ErbB Receptors / Q000378:metabolism*; D006341:Heart Rupture / Q000209:etiology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000150:complications / Q000378:metabolism*; D058628:Myofibroblasts / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000378:metabolism*; D020257:Ventricular Remodeling / Q000187:drug effects
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D019717:Tissue Inhibitor of Metalloproteinase-3; D003094:Collagen; D066246:ErbB Receptors; D000068818:Cetuximab