All authors have no conflicts of interest.
A DNA binding mutation in estrogen receptor-α Leads to suppression of Wnt signaling via β-catenin destabilization in osteoblasts†
Article first published online: 9 MAY 2012
Copyright © 2012 Wiley Periodicals, Inc.
Journal of Cellular Biochemistry
Volume 113, Issue 7, pages 2248–2255, July 2012
How to Cite
Mödder, U. I., Rudnik, V., Liu, G., Khosla, S. and Monroe, D. G. (2012), A DNA binding mutation in estrogen receptor-α Leads to suppression of Wnt signaling via β-catenin destabilization in osteoblasts. J. Cell. Biochem., 113: 2248–2255. doi: 10.1002/jcb.24095
- Issue published online: 9 MAY 2012
- Article first published online: 9 MAY 2012
- Accepted manuscript online: 14 FEB 2012 09:53AM EST
- Manuscript Accepted: 2 FEB 2012
- Manuscript Received: 31 JAN 2012
- National Institutes of Health (NIH). Grant Number: P01-AG004875
- Mayo Kogod Aging Center
- ESTROGEN RECEPTOR;
Estrogen receptors (ERs) play vital roles in the function and remodeling of bone. Their cellular mechanisms can broadly be categorized into those involving direct DNA binding (classical) or indirect DNA binding (non-classical). The generation of non-classical ER knock-in (ERα−/NERKI) mice provides a unique opportunity to define these pathways in bone. We previously demonstrated that ERα−/NERKI mice exhibit an osteoporotic phenotype; however, the mechanism(s) for this remain unresolved. Gene expression analyses of cortical bone from ERα−/NERKI mice revealed suppression of lymphoid enhancer factor-1 (Lef1), a classic Wnt-responsive transcription factor that associates with β-catenin. Since Wnt signaling is generally considered bone anabolic, this observation leads to the hypothesis that NERKI-induced suppression of Wnt signaling may contribute to the low bone mass phenotype. We generated ERα−/NERKI mice crossed with the Wnt-responsive TOPGAL transgenic mouse model and observed significantly less β-galactosidase activity in ERα−/NERKI mice, confirming suppression of Wnt activity in vivo. Adenoviral expression of the NERKI receptor using an in vitro cell system resulted in the induction of several secreted antagonists of Wnt signaling. Furthermore, expression of NERKI abrogated Wnt10b-dependent Wnt activation using a lentiviral-mediated reporter assay. Finally, expression of NERKI destabilized β-catenin cellular protein levels and disrupted ER/β-catenin interactions. Collectively, these data suggest the osteoporotic phenotype of ERα−/NERKI mice may involve the suppression of Lef1-mediated Wnt signaling through both the stimulation of secreted Wnt inhibitors and/or disruption of normal β-catenin function. J. Cell. Biochem. 113: 2248–2255, 2012. © 2012 Wiley Periodicals, Inc.