Unraveling the dynamic oxidative processes afer ischemia/reperfusion in the heart using new proteomics approaches

Abstract

After an episode of coronary artery occlusion, myocardial response to reperfusion does not remain stable during time. Although there are many relevant proteomic changes taking place in the tissue, systematic studies are lacking on the protein modification changes occurring in the post-reperfused myocardium along the first week after I/R. In this Doctoral Thesis we present the application of global PTMs analysis combined with the mapping of redox-active thiols in myocardial tissue proteins to study the oxidative and molecular dynamic changes after I/R. After ischemia, blood flow restoration generates an initial oxidative damage, generated in the mitochondria, that we detected at 20 minutes after reperfusion. This initial and intracellular oxidative wave consisted on irreversible monooxidations and affected intracellular proteins essential for cardiac function. Later, starting at 2h and peaking at 24h after reperfusion, immune cells, including neutrophils, are recruited to the lesion site as part of the cardiac inflammatory process. We detected an increase in neutrophil’s granule peroxidases in the tissue, as well as a second oxidative wave consisting on irreversible dioxidations and trioxidations and also Cysteine reversible oxidation, in extracellular and membrane proteins. Towards the end of the first week and with the start of the repair and fibrotic phase, we detected an increase in collagen proline-hydroxilations as well as lipid peroxidation accumulation in the tissue. Additionally, these results were validated in other animal models. This doctoral thesis provides the first systematic understanding of the timeline of the different oxidative processes during the first week after I/R. This study comprises the deep study of the posttranslationally modified peptidome, the redoxome and the proteome in a highly translational pig model, and might have implications on the definition of the disease progression and in the prediction and future approaches of the disease.