Coronary artery disease (CAD) is a chronic inflammatory disease having a long asymptomatic phase of fatty-fibrous development in arteries leading to angina, myocardial infarction, and death. Researchers at the All India Institute of Medical Sciences aimed to identify differential protein expression profiling of uEVs in CAD. The researchers collected urine samples of CAD patients (n = 41) age 18–65 years and gender matched healthy controls (n = 41). They isolated uEVs using differential ultracentrifugation. Further, uEV samples were characterized by western blotting exosome markers (Flotillin, TSG, CD63, and CD9), nano tracking analysis, and transmission and scanning electron microscopy. A total of 508 proteins were identified by iTRAQ-based mass spectrometry. The researchers observed protein expression levels of AZGP1, SEMG1/2, ORM1, IGL, SERPINA5, HSPG2, prosaposin, gelsolin, and CD59 were upregulated, and UMOD, KNG1, AMBP, prothrombin, and TF were downregulated. Protein-protein interactions, gene ontology and pathway analysis were performed to functionally annotate identified uEVs proteins. A novel uEVs differential protein signature is shown. On validating UMOD protein by ELISA in two clinically different CAD, stable-CAD patients had lower levels than healthy controls whereas recent myocardial infarction patients had lowest. Our findings suggest UMOD importance as early diagnostic biomarker.
Overview for identification of biomarkers from uEVs protein
(A) Discovery phase for identification of differentially expressed proteins from CAD uEVs compared to age-gender matched controls using iTRAQ-based mass spectrometry. (B) Validation of UMOD in CAD uEVs proteins compared to age-gender matched controls using ELISA.