Online ISSN : 1347-5231
Print ISSN : 0031-6903
ISSN-L : 0031-6903
宝田 剛志
ジャーナル フリー

2019 年 139 巻 6 号 p. 867-871


The mesenchymal stem cell (MSC) is a type of tissue stem cell. In clinical studies, cultured MSCs have shown important therapeutic effects on diseases via both the reduction of neurological defects and the regulation of immune responses. However, in vivo MSC localization, function, and properties are poorly understood; therefore, the molecular understanding of MSC hierarchy is less advanced compared to hematopoietic stem cell hierarchy. Runt-related transcription factor 2 (Runx2) is an essential transcriptional regulator of osteoblast differentiation from MSCs. Runx2 deficiency in Paired-related homeobox 1 (Prrx1)-derived cells (Runx2Prrx1−/− mice) results in defective intramembranous ossification. Double-positive cells for Prrx1-GFP, and stem cell antigen-1 (Sca1) (Prrx1+Sca1+ cells) in the calvaria, express Runx2 at lower levels, and are more homogeneous and primitive compared with Prrx1+Sca1 cells. Our results suggest that osteoblast differentiation in vivo may begin at the Prrx1+Sca1+ MSC stage, with sequential progression to Prrx1+Sca1 cells, followed by Osterix+Prrx1Sca1 osteoblast precursors, which eventually form mature α1(I)-collagen+ osteoblasts. This research will enable us to better understand the in vivo molecular biology features of MSCs, leading to their therapeutic applications for tissue repair and regeneration.

© 2019 The Pharmaceutical Society of Japan
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