Journal of Proteome Research vol:15 pages:1995-2007
Human embryonic stem cells (hESCs) are promising in Regenerative Medicine (RM), due to their differentiation plasticity and proliferation potential. However, a major challenge in RM is the generation of a vascular system, to support nutrient flow to newly synthesized tissues. Here we refined an existing method to generate tight vessels, by differentiating hESCs in CD34+ Vascular Progenitor Cells (VPCs), using chemically defined media and growth conditions. We selectively purified these cells from CD34- outgrowth populations also formed. To analyze these differentiation processes, we compared the proteomes of the hESCs with those of the CD34+ and CD34- populations, using high resolution mass spectrometry, label-free quantification and multivariate analysis. 18 protein markers validate the differentiated phenotypes in immunological assays; 9 of these were also detected by proteomics and show statistically significant differential abundance. Another 225 proteins show differential abundance between the three cell types. 63 of these have known functions in CD34+ and CD34- cells. CD34+ cells synthesize proteins implicated in endothelial cell differentiation and smooth muscle formation, supporting the bipotent phenotype of these progenitor cells. CD34- cells are more heterogeneous synthesizing muscular/osteogenic/chondrogenic/adipogenic lineage markers. The remaining >150 differentially abundant proteins in CD34+ or CD34- cells raise testable hypotheses for future studies to probe vascular morphogenesis.