Resident cardiac progenitor cells have emerged as a potential source of adult stem cells for regeneration of damaged myocardium. Sca-1 cells, expressing Stem cell antigen-1 as a cell surface marker, are multipotent cells that were shown to differentiate into different cell types i.e. cardiomyocytes. Previous studies have reported that Sca-1 positive cells are able to home to the injured heart. However, the mechanism of improving cardiac function is still unclear. In the current study, we have profiled the proteome and transcriptome of Sca-1 positive cells in comparison with other endogenous heart cell types to unravel the molecular phenotype of the progenitor cells. Among the 861 proteins identified with high confidence in total, 331 non-redundant proteins were overrepresented in Sca-1 positive cells. Highly abundant candidates were mostly associated with cell growth and proliferation, cell migration and cytoskeletal organization. Transcriptional profiling disclosed significant expression of surface antigens such as CD31, CD36, CD38, CD66a, CD102, and CD202B. Growth factors like KITL, JAG2, PDGFB and VEGFC showed a higher expression in Sca-1 progenitor cells than in Sca-1 negative cells. Selective candidates were validated by Western blotting. These global findings provide a basis for the study of their capability to participate in the cardiac regeneration process.
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