Lineage-specific differentiation of osteogenic progenitors from pluripotent stem cells reveals the FGF1-RUNX2 association in neural crest-derived osteoprogenitors

Abstract

Human pluripotent stem cells (hPSCs) can provide a platform to model bone organogenesis and disease. To reflect the developmental process of the human skeleton, hPSC differentiation methods should include osteogenic progenitors (OPs) arising from three distinct embryonic lineages: the paraxial mesoderm, lateral plate mesoderm, and neural crest. Although OP differentiation protocols have been developed, the lineage from which they are derived, as well as characterization of their genetic and molecular differences, has not been well reported. Therefore, to generate lineage‐specific OPs from human embryonic stem cells and human induced pluripotent stem cells, we employed stepwise differentiation of paraxial mesoderm‐like cells, lateral plate mesoderm‐like cells, and neural crest‐like cells toward their respective OP subpopulation. Successful differentiation, confirmed through gene expression and in vivo assays, permitted the identification of transcriptomic signatures of all three cell populations. We also report, for the first time, high FGF1 levels in neural crest‐derived OPs—a notable finding given the critical role of fibroblast growth factors (FGFs) in osteogenesis and mineral homeostasis. Our results indicate that FGF1 influences RUNX2 levels, with concomitant changes in ERK1/2 signaling. Overall, our study further validates hPSCs' power to model bone development and disease and reveals new, potentially important pathways influencing these processes.

The Progress of Stem Cell Technology for Skeletal Regeneration

“…However, the paraxial and lateral plate mesoderm form most bones via endochondral ossification [ 13 ]. Based on the origins or mode of bone formation, different induction protocols have been established to generate skeletal cells from human pluripotent stem cells (hPSCs) [ 6 , 14 , 15 ]. Thus, we succinctly overview the current understanding of skeletal development and introduce each induction method.…”

“…Several protocols have been proposed for the stepwise induction of osteoblasts from the mesoderm or sclerotome derived from hPSCs and mPSCs [ 6 , 15 , 22 , 41 , 42 ]. In many cases, the conventional osteogenic medium is used as the basal medium containing fetal bovine serum, ascorbic acid, β-glycerophosphate, and dexamethasone [ 42 , 43 ].…”

“…The number of reports focusing on osteoblast induction via the lateral plate mesoderm is also limited. One study showed osteoblast induction via induced lateral plate mesoderm from human iPSCs (hiPSCs) by using manufactured osteogenic medium [ 6 ]. Overall, the protocols for the induction of skeletal cells from lateral plate mesoderm are still limited.…”

“…The first is to use induced pluripotent stem cells (iPSCs) or embryonic stem cells (ESCs), which can recapitulate the skeletal developmental process and differentiate into various skeletal cells. Because skeletal tissues are derived from multiple origins, multiple protocols have been established based on the understanding of the skeletal development [ 5 , 6 , 7 ]. The second strategy is to use stem cells purified from adult skeletal tissues.…”

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“…Furthermore, the knowledge gleaned from developmental studies of the neural crest has permitted the efficient generation of NCSCs from PSCs, 4 which may represent a valuable tool for the elucidation of the underlying mechanisms of NCSC‐associated diseases and pave the way for the generation of novel therapies. In the first of our Featured Articles published this month in STEM CELLS , Kidwai et al report on the stepwise differentiation and subsequent characterization of human (h)PSCs into lineage‐specific osteoprogenitor cells and highlight, for the first time, the importance of the FGF1‐RUNX2 axis in neural crest‐derived osteoprogenitor cell development and craniofacial development and disease 5 . In a Related Article published recently in STEM CELLS Translational Medicine , McMahill et al employed a canine model as a readily accessible and clinically realistic means to evaluate the consequences of transplanting epidermally‐derived NCSCs into the healthy spinal cord 6 …”