Proteome analysis of human Wharton's jelly cells during in vitro expansion

To better understand their self-renewal and potential in vitro expansion capacity, a reference 2D map was constructed as a proteomic data set. 158 unique proteins were identified. More than 30% of these proteins belong to cytoskeleton compartment. We also found that several proteins including Shootin1, Adenylate kinase 5 isoenzyme and Plasminogen activator-inhibitor 2 are no longer expressed after the 2nd passage of in vitro replication. This indicates that the proliferative potency of these cells is reduced after the initial stage of in vitro growing. At the end of cellular culturing, new synthesized proteins, including, ERO1-like protein alpha, Aspartyl-tRNA synthetase and Prolyl-4-hydroxylase were identified. It is suggested that these new synthesized proteins are involved in the impairment of cellular surviving during replication and differentiation time.Our work represents an essential step towards gaining knowledge of the molecular properties of WJCs so as to better understand their possible use in the field of cell therapy and regenerative medicine.Since the first identification of non-hematopoietic stem cells in the bone marrow as colony-forming unit-fibroblasts (CFU-Fs) and the detailed characterization and description of the tri-lineage potential of the mesenchymal stem cells (MSCs), our knowledge of the molecular properties of these cells has made great progress [1,2]. MSCs have a great appeal for tissue engineering and therapeutic applications because of their high in vitro expansion potential, self renewal capacity and multi-potentiality [3-5]. However, considering the invasive procedure related to their availability, there is an increasing interest in investigating the presence of MSCs in adult and fetal sources and especially their presence in fetal membranes such as umbilical cord matrix [6-9].In the umbilical cord two arteries and one vein, surrounded by mucoid connective tissue, called Wharton's jelly are present (figure 1). It contains fibroblast-