KEN OKAZAKI
   Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine
   Position   Professor and Division head
Article types Original article
Language English
Peer review Peer reviewed
Title FOXO1 transcription factor regulates chondrogenic differentiation through transforming growth factor β1 signaling.
Journal Formal name:The Journal of biological chemistry
Abbreviation:J Biol Chem
ISSN code:1083351X/00219258
Domestic / ForeginForegin
Volume, Issue, Page 294(46),pp.17555-17569
Author and coauthor Kurakazu Ichiro, Akasaki Yukio, Hayashida Mitsumasa, Tsushima Hidetoshi, Goto Norio, Sueishi Takuya, Toya Masakazu, Kuwahara Masanari, Okazaki Ken, Duffy Tomas, Lotz Martin K, Nakashima Yasuharu
Publication date 2019/11
Summary The forkhead box O (FOXO) proteins are transcription factors involved in the differentiation of many cell types. Type II collagen (Col2) Cre-Foxo1-knockout and Col2-Cre-Foxo1,3,4 triple-knockout mice exhibit growth plate malformation. Moreover, recent studies have reported that in some cells, the expressions and activities of FOXOs are promoted by transforming growth factor β1 (TGFβ1), a growth factor playing a key role in chondrogenic differentiation. Here, using a murine chondrogenic cell line (ATDC5), mouse embryos, and human mesenchymal stem cells, we report the mechanisms by which FOXOs affect chondrogenic differentiation. FOXO1 expression increased along with chondrogenic differentiation, and FOXO1 inhibition suppressed chondrogenic differentiation. TGFβ1/SMAD signaling promoted expression and activity of FOXO1. In ATDC5, FOXO1 knockdown suppressed expression of sex-determining region Y box 9 (Sox9), a master regulator of chondrogenic differentiation, resulting in decreased collagen type II α1 (Col2a1) and aggrecan (Acan) expression after TGFβ1 treatment. On the other hand, chemical FOXO1 inhibition suppressed Col2a1 and Acan expression without suppressing Sox9 To investigate the effects of FOXO1 on chondrogenic differentiation independently of SOX9, we examined FOXO1's effects on the cell cycle. FOXO1 inhibition suppressed expression of p21 and cell-cycle arrest in G0/G1 phase. Conversely, FOXO1 overexpression promoted expression of p21 and cell-cycle arrest. FOXO1 inhibition suppressed expression of nascent p21 RNA by TGFβ1, and FOXO1 bound the p21 promoter. p21 inhibition suppressed expression of Col2a1 and Acan during chondrogenic differentiation. These results suggest that FOXO1 is necessary for not only SOX9 expression, but also cell-cycle arrest during chondrogenic differentiation via TGFβ1 signaling.
DOI 10.1074/jbc.RA119.009409
PMID 31601652