title: Comparative analysis of mouse-induced pluripotent stem cells and mesenchymal stem cells during osteogenic differentiation in vitro.
abstract: Induced pluripotent stem cells (iPSCs) can differentiate into mineralizing cells and are, therefore, expected to be useful for bone regenerative medicine; however, the characteristics of iPSC-derived osteogenic cells remain unclear. Here, we provide a direct in vitro comparison of the osteogenic differentiation process in mesenchymal stem cells (MSCs) and iPSCs from adult C57BL/6J mice. After 30 days of culture in osteogenic medium, both MSCs and iPSCs produced robustly mineralized bone nodules that contained abundant calcium phosphate with hydroxyapatite crystal formation. Mineral deposition was significantly higher in iPSC cultures than in MSC cultures. Scanning electron microscopy revealed budding matrix vesicles in early osteogenic iPSCs; subsequently, the vesicles propagated to exhibit robust mineralization without rich fibrous structures. Early osteogenic MSCs showed deposition of many matrix vesicles in abundant collagen fibrils that became solid mineralized structures. Both cell types demonstrated increased expression of osteogenic marker genes, such as runx2, osterix, dlx5, bone sialoprotein (BSP), and osteocalcin, during osteogenesis; however, real-time reverse transcription-polymerase chain reaction array analysis revealed that osteogenesis-related genes encoding mineralization-associated molecules, bone morphogenetic proteins, and extracellular matrix collagens were differentially expressed between iPSCs and MSCs. These data suggest that iPSCs are capable of differentiation into mature osteoblasts whose associated hydroxyapatite has a crystal structure similar to that of MSC-associated hydroxyapatite; however, the transcriptional differences between iPSCs and MSCs could result in differences in the mineral and matrix environments of the bone nodules. Determining the biological mechanisms underlying cell-specific differences in mineralization during in vitro iPSC osteogenesis may facilitate the development of clinically effective engineered bone.
authors.affiliation: 1 Division of Oromaxillofacial Regeneration, Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry , Suita, Osaka, Japan .
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Egusa
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kayashima
authors.forename: Jiro
authors.initials: J
authors.lastname: Miura
authors.forename: Shinya
authors.initials: S
authors.lastname: Uraguchi
authors.forename: Fangfang
authors.initials: F
authors.lastname: Wang
authors.forename: Hiroko
authors.initials: H
authors.lastname: Okawa
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Sasaki
authors.forename: Makio
authors.initials: M
authors.lastname: Saeki
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yatani
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002113:Calcification, Physiologic / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D005109:Extracellular Matrix / Q000378:metabolism; D005786:Gene Expression Regulation; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000648:ultrastructure; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000648:ultrastructure; D008810:Mice, Inbred C57BL; D010012:Osteogenesis / Q000235:genetics
chemical_list: D015415:Biomarkers