iPSC-derived mesenchymal stromal cells are less supportive than primary MSCs for co-culture of hematopoietic progenitor cells.

In vitro culture of hematopoietic stem and progenitor cells (HPCs) is supported by a suitable cellular microenvironment, such as mesenchymal stromal cells (MSCs)-but MSCs are heterogeneous and poorly defined. In this study, we analyzed whether MSCs derived from induced pluripotent stem cells (iPS-MSCs) provide a suitable cellular feeder layer too. iPS-MSCs clearly supported proliferation of HPCs, maintenance of a primitive immunophenotype (CD34(+), CD133(+), CD38(-)), and colony-forming unit (CFU) potential of CD34(+) HPCs. However, particularly long-term culture-initiating cell (LTC-IC) frequency was lower with iPS-MSCs as compared to primary MSCs. Relevant genes for cell-cell interaction were overall expressed at similar level in MSCs and iPS-MSCs, whereas VCAM1 was less expressed in the latter. In conclusion, our iPS-MSCs support in vitro culture of HPCs; however, under the current differentiation and culture conditions, they are less suitable than primary MSCs from bone marrow.