Derivation of functional mesenchymal stem cells from human induced pluripotent stem cells cultured on synthetic polymer substrates

摘要

Human induced pluripotent stem (iPS) cells may represent the ideal cell source for research and applications in regenerative medicine. However, standard culture conditions that depend on the use of undefined substrates and xenogeneic medium components represent a significant obstacle to clinical translation. Recently, we reported a defined culture system for human embryonic stem (ES) cells using a fully defined synthetic polymer coating, poly[2-(methacryloyloxy)ethyl dimethyl-(3-sulfopropyl)ammonium hydroxide] (PMEDSAH), in conjunction with xeno-free and defined culture medium. Here we tested the hypothesis that iPS cells grown in this defined culture system can be differentiated into mesenchymal stem cells (iPS-MSCs). Human iPS cells were cultured on PMEDSAH and differentiated into functional MSCs, as confirmed by expression of characteristic MSC markers (CD166+, CD105+, CD73+, CD44+, CD34− and CD45−) and their ability to differentiate in vitro into adipogenic, chondrogenic and osteoblastic lineages. To demonstrate the potential of iPS-MSCs to regenerate bone in vivo, the newly derived cells were induced to osteoblast differentiation for 4 days and transplanted into calvaria defects in immoncompromised mice for 8 weeks. MicroCT analysis and histology demonstrated de novo bone formation in the calvaria defects for animals treated with iPS-MSCs, but not for the control group. Moreover, positive staining for human nuclear antigen and human mitochondria monoclonal antibodies unambiguously confirmed the participation of the transplanted human iPS-MSCs in the regenerated bone. These results confirmed that human iPS cells grown in a defined and xeno-free system have the capability to differentiate into functional MSCs with the ability to form bone in vivo.