Identification of Early Protein Damage-Associated Molecular Pattern (DAMPs) Candidates from Cardiac Cells Subjected to an In Vitro Myocardial Ischemic Injury

Damage-associated molecular patterns (DAMPs) are intracellular molecules that are released from cells that undergo injury. Protein-DAMPs are abundant biomolecules that could potentially be a novel biomarker for pathology. Myocardial ischemia injury is a causative process for ischemic heart disease, which is now the leading cause of global deaths. Early diagnosis is necessary to save patient lives, so the discovery of new early cardiac biomarkers is crucial. Here, we examined the protein-DAMPs expression in ischemic buffer collected from adult ventricular myocytes cells subjected to various timepoints of simulated ischemia (sI). Adult ventricular myocytes cells (AC-16) were subjected to sublethal simulated ischemia (sI) by treatment with ischemic buffer for 5, 10, 20, and 30 minutes (I5, I10, I20, and I30, respectively). After simulated ischemia was achieved, the ischemic buffer was collected and determined for proteins profiling by Shotgun proteomics approach. Cell viability was reduced in a time dependent manner in ischemia. Targeted proteomics reveals 21 proteins found to highly increase in early ischemic injury and can still be detected until 30 minutes of ischemia. Lactotransferrin (LTF) was determined to be the protein with the greatest impact, exhibiting both fast and sustained release throughout the whole study time. The present study identified the protein damage associated molecular pattern (DAMPs) released specifically from ischemia-induced cardiomyocytes injury, which could potentially be candidates to be early biomarkers for myocardial ischemic injury. Further studies should be focused on in vivo validation of potential protein markers that could be used in practical clinical applications.