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Mol Cell Biochem. 2008 Mar;310(1-2):11-8. Epub 2007 Dec 2.

Critical role of phosphoinositide 3-kinase cascade in adipogenesis of human mesenchymal stem cells.

Author information

1
Center for Stem Cell Biology and Tissue Engineering, Sun Yat-sen University, 74 Zhongshan Road 2, Guangzhou, Guangdong 510080, PR China.

Abstract

Mesenchymal stem cells (MSCs) are multipotent stem cells capable of differentiating into adipocytes in the presence of a hormone cocktail. These cells thus provide a promising model for studying the early events of adipogenesis. Here, we examine the involvement of the PI3K/Akt and mTOR/p70S6K signaling pathways in human MSC adipogenesis. We found that the two pathways were strongly activated with a similar temporal profile under the adipogenesis-inducing hormone cocktail and this activation could be blocked by LY294002, a specific inhibitor of PI3K. Furthermore, rapamycin, a specific inhibitor of mTOR, blocked the activation of mTOR/p70S6K but not PI3K/Akt. Both LY294002 and rapamycin severely suppressed lipid accumulation, as well as the expression of adipogenic markers, including PPAR gamma 2 and C/EBP alpha, two master adipogenic transcription factors. Together, these data indicate that the mTOR/p70S6K pathway acts downstream of the PI3K/Akt pathway in mediating the adipogenic conversion of MSCs. In conclusion, our data suggest that the PI3K/Akt and mTOR/p70S6K signaling pathways are essential for adipogenesis of human MSCs.

PMID:
18060476
DOI:
10.1007/s11010-007-9661-9
[Indexed for MEDLINE]

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