Proteomics Characterization of Extracellular Space Components in the Human Aorta*□S

The vascular extracellular matrix (ECM) is essential for the structural integrity of the vessel wall and also serves as a substrate for the binding and retention of secreted prod-ucts of vascular cells as well as molecules coming from the circulation. Although proteomics has been previously applied to vascular tissues, few studies have specifically targeted the vascular ECM and its associated proteins. Thus, its detailed composition remains to be character-ized. In this study, we describe a methodology for the extraction of extracellular proteins from human aortas and their identification by proteomics. The approach is based on (a) effective decellularization to enrich for scarce extracellular proteins, (b) successful solubilization and deglycosylation of ECM proteins, and (c) relative es-timation of protein abundance using spectral counting