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Tissue-Specific Stem Cells
Article first published online: 5 JUL 2013
Copyright © 2013 AlphaMed Press
Volume 31, Issue 7, pages 1340–1349, July 2013
How to Cite
Dieudonne, F.-X., Sévère, N., Biosse-Duplan, M., Weng, J.-J., Su, Y. and Marie, P. J. (2013), Promotion of Osteoblast Differentiation in Mesenchymal Cells Through Cbl-Mediated Control of STAT5 Activity. STEM CELLS, 31: 1340–1349. doi: 10.1002/stem.1380
Author contributions: F.X.D., N.S., and P.J.M.: conception and design, collection and/or assembly of data, data analysis and interpretation, and manuscript writing; M.B.D., J.J.W., and Y.S.: provision of study material and final approval of manuscript.
Disclosure of potential conflicts of interest is found at the end of this article.
first published online in STEM CELLS EXPRESS March 26, 2013.
- Issue published online: 5 JUL 2013
- Article first published online: 5 JUL 2013
- Accepted manuscript online: 26 MAR 2013 08:24AM EST
- Manuscript Accepted: 28 FEB 2013
- Manuscript Received: 19 SEP 2012
- Agence Nationale de la Recherche. Grant Number: ANR-09-BLAN-0402-01
- Ministère de la Recherche (Paris, France)
- Harvard Dental School of Medicine, USA
- AP-HP. Grant Number: INSERM U781
- Université Paris Descartes, Paris, France
- Mesenchymal cells;
- c-Cbl ubiquitin ligase;
- Osteoblast differentiation;
The identification of the molecular mechanisms controlling the degradation of regulatory proteins in mesenchymal stromal cells (MSC) may provide clues to promote MSC osteogenic differentiation and bone regeneration. Ubiquitin ligase-dependent degradation of proteins is an important process governing cell fate. In this study, we investigated the role of the E3 ubiquitin ligase c-Cbl in MSC osteoblast differentiation and identified the mechanisms involved in this effect. Using distinct shRNA targeting c-Cbl, we showed that c-Cbl silencing promotes osteoblast differentiation in murine and human MSC, as demonstrated by increased alkaline phosphatase activity, expression of phenotypic osteoblast marker genes (RUNX2, ALP, type 1 collagen), and matrix mineralization in vitro. Coimmunoprecipitation analyses showed that c-Cbl interacts with the transcription factor STAT5, and that STAT5 forms a complex with RUNX2, a master transcription factor controlling osteoblastogenesis. Silencing c-Cbl decreased c-Cbl-mediated STAT5 ubiquitination, increased STAT5 protein level and phosphorylation, and enhanced STAT5 and RUNX2 transcriptional activity. The expression of insulin like growth factor-1 (IGF-1), a target gene of STAT5, was increased by c-Cbl silencing in MSC and in bone marrow stromal cells isolated from c-Cbl deficient mice, suggesting that IGF-1 contributes to osteoblast differentiation induced by c-Cbl silencing in MSC. Consistent with these findings, pharmacological inhibition of STAT5 activity, or neutralization of IGF-1 activity, abrogated the positive effect of c-Cbl knockdown on MSC osteogenic differentiation. Taken together, the data provide a novel functional mechanism by which the ubiquitin ligase c-Cbl regulates the osteoblastic differentiation program in mesenchymal cells by controlling Cbl-mediated STAT5 degradation and activity. STEM Cells2013;31:1340–1349