Study of molecular mechanisms of myocardial infarction: analysis of deep proteome and redoxome in a pig model of ischemia/reperfusio

Myocardial infarction (MI), together with other cardiovascular diseases (CVD), are the leading cause of death worldwide. The modern lifestyle is closely connected to the development of cardiovascular affections and the number of death is astounding and impacting the world population at an increasing rate. After an episode of coronary artery occlusion, reperfusion alters the healing process in the heart; however, systematic studies are lacking on the early molecular changes following ischemia/reperfusion (I/R). Moreover, alterations in the remote myocardium have been neglected, even though this region contributes to the development of post-MI heart failure (HF). In this Doctoral Thesis we have characterized the changes in protein expression, oxidative levels and lipid dynamics in the ischemic and remote pig myocardium during the first week after MI, the molecular impact of protective treatments and the proteome alterations taking place in four distinct cardiac cell types separately (cardiomyocytes (CM), endothelial cells (EC), fibroblasts (FB) and macrophages (Mφ). At early reperfusion (120 min), the ischemic area showed a coordinated increase of inflammatory processes, whereas interstitial proteins, angiogenesis and cardio-renal signaling processes increased at later reperfusion (day 4 and 7). In the remote myocardium, unbalanced contractility at 120 min and 24 hours was manifested by transient alterations in contractile and mitochondrial proteins. Subsequent recovery of regional contractility was accompanied by increases in inflammation and wound healing proteins on post-MI day 7. Reversible cysteine oxidation was detected within the ischemic myocardium tissue and peaked at 24 hours post-MI. This reversible oxidative damage decreased in the presence of pre-conditioning treatment and when no reperfusion was performed. Moreover, the acute inflammatory response was attenuated by preconditioning, most probably through modulation of immune cells and also protection of sarcomeric proteins from reperfusion-driven decrease. Structural membrane lipid profiles showed noncoordinated changes in the ischemic area that could reflect dynamic cellular content alterations. Other lipid classes involved in inflammatory signaling and response to the increased demand for oxygen consumption in the post-MI heart were altered in synchrony and their changes were less pronounced in the remote region. Individual cell type protein signature analysis showed an increase in proteins implicated in the communication with immune system cells and in the propagation of inflammatory responses in early reperfusion (day 3) in CM, EC and Mφ, while in FB protein changes reflected proteolytic reorganization of the extracellular matrix in the lesion microenvironment. Viable surviving CM underwent transitory down regulation of metabolic and contractile functions in the early reperfusion phase, which in part resembled the alterations in the remote myocardium, and managed to restore them by the end of the week after I/R cardiac insult. These data provide the first detailed map of molecular alterations that the heart suffers in the first hours and days after MI. It comprises the deep study of the proteome, redoxome and lipidome in a highly translational pig model and might have implications for the definition of new therapeutic targets and diagnosis for improving early post-MI remodeling.