Mesenchymal stem cells as an appropriate feeder layer for prolonged in vitro culture of human induced pluripotent stem cells

Feeder layers have been applied extensively to support the growth and stemness potential of stem cells for in vitro cultures. Mouse embryonic fibroblast and mouse fibroblast cell line (SNL) are common feeder cells for human induced pluripotent stem cells (hiPSCs) culture. Because of some problems in the use of these animal feeders and in order to simplify the therapeutic application of hiPSCs, we tested human adult bone marrow mesenchymal stem cells (hMSCs) as a potent feeder system. This method benefits from prevention of possible contamination of animal origin feeder systems. hiPSCs transferred onto mitotically inactivated hMSCs and passaged every 5 days. Prior to this culture, MSCs were characterized by flow cytometry of their surface markers and evaluation of their osteogenic and adipogenic differentiation potentials. The morphology, expressions of some specific pluripotency markers such as SSEA-3, NANOG and TRA-1-60, alkaline phosphates activity, formation embryoid bodies and their differentiation potentials of iPSCs on SNL and MSC feeder layers were evaluated. To investigate the prolonged maintenance of pluripotency, the quantitative transcriptions of some pluripotency markers including OCT4, SOX2, NANOG and REX1 were compared in the iPS clones on SNL or MSC feeders. Human iPSCs cultured on human MSCs feeder were slightly thinner and flatter than ones on the other feeder system. Interestingly MSCs supported the prolonged in vitro proliferation of hiPSCs along with maintenance of their pluripotency. Altogether our results suggest human mesenchymal stem cells as an appropriate feeder layer for human iPSCs culture for clinical applications and cell therapy.