Label-free quantitative proteomics analysis reveals distinct molecular characteristics in endocardial endothelium.

Endocardial endothelium, which lines the chambers of the heart, is distinct in its origin, structure, and function. Characterization studies using genomics and proteomics have reported molecular signatures supporting the structural and functional heterogeneity of various endothelial cells. However, though functionally very important, no studies at protein level have been conducted so far characterizing endocardial endothelium. In this study, we used endothelial cells from pig heart to investigate if endocardial endothelial cells are distinct at the proteome level. Using a high-throughput liquid chromatography-tandem mass spectrometry for proteome profiling and expression, we identified sets of proteins that belong to specific biological processes and metabolic pathways in endocardial endothelial cells supporting its specific structural and functional roles. The study also identified several transcription factors and cell surface markers, which may have roles in the specificity of endocardial endothelium. The detection of sets proteins preferentially expressed in endocardial endothelium offers new insights into its role in the regulation of cardiac function. Data are made available through ProteomeXchange with identifier PXD009194.