Commitment of human mesenchymal stromal cells to skeletal lineages is independent of their morphogenetic capacity

Figure 5 Mesenchymal stromal cells commit to limb mesodermal lineages but are not capable of forming skeletal structures. Mesenchymal stromal cells (MSCs) from umbilical cord blood (UCB) and placenta (PL) differentiated into chondrogenic, osteogenic, and tenogenic lineages in vitro. However, under the influence of differentiation and morphogenetic signals from limb ectoderm in the recombinant limb (RL) system, MSCs committed to limb lineages but failed to organize into tridimensional structures and form skeletal elements as observed with limb bud mesodermal cells under the same conditions. Similarly, the response to ectodermal signals depended on the source of MSCs: UCB-RLs had higher expression of osteogenic and tenogenic markers than PL-RLs, whereas in PL-RLs, tenogenic markers were downregulated after receiving ectodermal signals. UCB: Umbilical cord blood; PL: Placenta; LBMC: Limb bud mesodermal cell; RL: Recombinant limb.