Proteomics of urinary exosomes for discovering novel non-invasive biomarkers of acute myocardial infarction patients

Background: Patients with acute myocardial infarction (AMI) can be identified by myocardial enzymes in peripheral blood, but no protein markers have been found in urinary exosomes derived from AMI patients. Methods: In the present study, a comprehensive proteomics analysis of urinary exosomes derived from patients with AMI was performed. Firstly, we employed the outstanding separation method known as EXODUS to isolate urinary exosomes from AMI patients and healthy controls. Then, we characterized urinary exosomes by nano- particle tracking analysis (NTA), western blotting and transmission electron microscopy (TEM). After that, we identified the protein components of exosomes through label-free proteomics and conducted bioinformatics analysis. Result: High-quality exosomes were obtained through separation using EXODUS, which could be demonstrated by NTA, Western blotting and TEM. NTA analysis showed that partilce amount in AMI patients was significantly higher than healthy controls. The equal-volume Western blotting experiment indicated that the expression level of classic exosomal markers Alix, heat shock protein90 (HSP90), CD63 and TSG101 (Tumor susceptibility gene101) in AMI patents was obviously stronger than healthy subjects. We first described the protein profiles of urinary exosomes in AMI patients through proteomics. In this study, We have identified 3194 proteins, among which a total of 30 differential proteins were detected between the urinary exosomes of AMI patients and healthy controls. We investigated F2 and OLR1 among identified exosomal proteins significantly elevated in AMI group, whereas F3 and APCS dysregulated in AMI development. Conclusions: F2, F3, OLR1 and APCS are able to distinguish individuals between the AMI group and the healthy controls, and the protein panel represent a novel prospective non-invasive biomarkers for the diagnostic process of acute myocardial infarction.