Specific integrin expression is associated with podosome-like structures on mesodermal progenitor cells.

Mesenchymal stromal cells (MSCs) are a heterogeneous cell population capable of differentiating toward several cell lines in vitro and, possibly, in vivo. Within cultured MSCs, we identified and purified a precursor cell population [mesodermal progenitor cells (MPCs)] retaining robust proliferation potential and ability to differentiate into endothelial or mesenchymal cells. MPC-derived MSCs retain the ability to further differentiate into osteoblasts, cartilage, or fat cells. Here we further characterized MPCs and MSCs by evaluating expression of integrins and adhesion molecules showing their ability to assemble the molecular machinery involved in endothelium adhesion. MPCs were shown to interact with activated and nonactivated endothelium, whereas MSCs exhibited activation of focal adhesion complexes, higher cell motility, and reduced or absent adhesiveness onto endothelial cells, suggesting a matrix remodeling vocation. We also reported a consistent expression of CXCR4 on the MPC cell surface, suggesting that the different phenotypic behavior could be related to specific functions of the cell in each differentiation stage.