Improved proteomic profiling of the cell surface of culture-expanded human bone marrow multipotent stromal cells

A comprehensive analysis of the membrane proteome is essential to explain the biology of multipotent stromal cells and identify reliable protein biomarkers for the isolation as well as tracking of cells during differentiation and maturation. However, proteomic analysis of membrane proteins is challenging and they are noticeably under-represented in numerous proteomic studies. Here we introduce new approach, which includes high pressure-assisted membrane protein extraction, protein fractionation by gel-eluted liquid fraction entrapment electrophoresis (GELFREE), and combined use of liquid chromatography MALDI and ESI tandem mass spectrometry. This report presents the first comprehensive proteomic analysis of membrane proteome of undifferentiated and culture-expanded human bone marrow multipotent stromal cells (hBM-MSC) obtained from different human donors. Gene ontology mapping using the Ingenuity Pathway Analysis and DAVID programs revealed the largest membrane proteomic dataset for hBM-MSC reported to date. Collectively, the new workflow enabled us to identify at least two-fold more membrane proteins compared to published results on hBM-MSC. A total of 84 CDs were identified including 14 CDs identified for the first time. This dataset can serve as a basis for further exploration of self-renewal, differentiation and characterization of hBM-MSC.