The effects of cyclin-dependent kinase inhibitors on adipogenic differentiation of human mesenchymal stem cells.
The molecular mechanisms that couple growth arrest and cell differentiation were examined during adipogenesis. Here, to understand the cyclin-dependent kinase inhibitor (CKI) genes involved in the progression of adipogenic differentiation, we examined changes in the protein and mRNA expression levels of CKI genes in vitro. During the onset of growth arrest associated with adipogenic differentiation, two independent families of CKI genes, p27Kip1 and p18INK4c, were significantly increased. The expressions of p27Kip1 and p18INK4c, regulated at the level of protein and mRNA accumulation, were directly coupled to adipogenic differentiation. This finding was supported by the inhibition of adipogenic differentiation caused by short interfering RNA (siRNA). In this study, we investigated the regulatory effects of transforming growth factor beta-1 (TGFbeta-1) on CKI genes involved in adipogenic differentiation of bone marrow-derived human mesenchymal stem cells (hMSCs). Only the up-regulation of p18INK4c during adipogenic differentiation, and not that of the p27Kip1 gene was prevented by treatment with TGFbeta-1, one of the factors that inhibit adipogenesis in vitro. This finding indicates a close correlation between adipogenic differentiation and p18INK4c induction in hMSCs. Thus, these data demonstrate a role for the differentiation-dependent cascade expression of cyclin-dependent kinase inhibitors in regulating adipogenic differentiation, thereby providing a molecular mechanism that couples growth arrest and differentiation.
Kang
Jin Wook
JW
Biotechnological Development Assistance Team, National Institute of Toxicological Research, Korea Food & Drug Administration, 194 Nokbun-dong, Eunpyung-ku, Seoul 122-704, Republic of Korea.
Choi
Youngju
Y
Park
Jae Hyun
JH
Kim
Ji Seon
JS
Park
Ki Dae
KD
Baek
Dae Hyun
DH
Seong
Su-Kyoung
SK
Choi
Kyoung Suk
KS
Lim
So Yoon
SY
Kim
Hyung Soo
HS
D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D050156:Adipogenesis / Q000187:drug effects / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D050756:Cyclin-Dependent Kinase Inhibitor Proteins / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology*
D050756:Cyclin-Dependent Kinase Inhibitor Proteins; D018844:Cyclin-Dependent Kinases