Silencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation

Hdl Handle:
http://hdl.handle.net/10147/237774
Title:
Silencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation
Authors:
Butler, Joseph S; Queally, Joseph M; Devitt, Brian M; Murray, David W; Doran, Peter P; O'Byrne, John M
Citation:
BMC Musculoskeletal Disorders. 2010 Sep 15;11(1):210
Issue Date:
15-Sep-2010
URI:
http://dx.doi.org/10.1186/1471-2474-11-210; http://hdl.handle.net/10147/237774
Abstract:
Abstract Background The Wnt/β-catenin pathway is a major signaling cascade in bone biology, playing a key role in bone development and remodeling. The objectives of this study were firstly, to determine the effects of dexamethasone exposure on Wnt/β-catenin signaling at an intracellular and transcriptional level, and secondly, to assess the phenotypic effects of silencing the Wnt antagonist, Dickkopf-1 (Dkk1) in the setting of dexamethasone exposure. Methods Primary human osteoblasts were exposed in vitro to 10-8 M dexamethasone over a 72 h time course. The phenotypic marker of osteoblast differentiation was analyzed was alkaline phosphatase activity. Intracellular β-catenin trafficking was assessed using immunoflourescence staining and TCF/LEF mediated transcription was analyzed using a Wnt luciferase reporter assay. Dkk1 expression was silenced using small interfering RNA (siRNA). Results Primary human osteoblasts exposed to dexamethasone displayed a significant reductions in alkaline phosphatase activity over a 72 h time course. Immunoflourescence analaysis of β-catenin localization demonstrated a significant reduction in intracytosolic and intranuclear β-catenin in response to dexamethasone exposure. These changes were associated with a reduction of TCF/LEF mediated transcription. Silencing Dkk1 expression in primary human osteoblasts exposed to dexamethasone resulted in an increase in alkaline phosphatase activity when compared to scrambled control. Conclusions Wnt/β-catenin signaling plays a key role in regulating glucocorticoid-induced osteoporosis in vitro. Silencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation. Targeting of the Wnt/β-catenin signaling pathway offers an exciting opportunity to develop novel anabolic bone agents to treat osteoporosis and disorders of bone mass.
Item Type:
Journal Article

Full metadata record

DC FieldValue Language
dc.contributor.authorButler, Joseph S-
dc.contributor.authorQueally, Joseph M-
dc.contributor.authorDevitt, Brian M-
dc.contributor.authorMurray, David W-
dc.contributor.authorDoran, Peter P-
dc.contributor.authorO'Byrne, John M-
dc.date.accessioned2012-08-08T15:11:04Z-
dc.date.available2012-08-08T15:11:04Z-
dc.date.issued2010-09-15-
dc.identifier.citationBMC Musculoskeletal Disorders. 2010 Sep 15;11(1):210-
dc.identifier.urihttp://dx.doi.org/10.1186/1471-2474-11-210-
dc.identifier.urihttp://hdl.handle.net/10147/237774-
dc.description.abstractAbstract Background The Wnt/β-catenin pathway is a major signaling cascade in bone biology, playing a key role in bone development and remodeling. The objectives of this study were firstly, to determine the effects of dexamethasone exposure on Wnt/β-catenin signaling at an intracellular and transcriptional level, and secondly, to assess the phenotypic effects of silencing the Wnt antagonist, Dickkopf-1 (Dkk1) in the setting of dexamethasone exposure. Methods Primary human osteoblasts were exposed in vitro to 10-8 M dexamethasone over a 72 h time course. The phenotypic marker of osteoblast differentiation was analyzed was alkaline phosphatase activity. Intracellular β-catenin trafficking was assessed using immunoflourescence staining and TCF/LEF mediated transcription was analyzed using a Wnt luciferase reporter assay. Dkk1 expression was silenced using small interfering RNA (siRNA). Results Primary human osteoblasts exposed to dexamethasone displayed a significant reductions in alkaline phosphatase activity over a 72 h time course. Immunoflourescence analaysis of β-catenin localization demonstrated a significant reduction in intracytosolic and intranuclear β-catenin in response to dexamethasone exposure. These changes were associated with a reduction of TCF/LEF mediated transcription. Silencing Dkk1 expression in primary human osteoblasts exposed to dexamethasone resulted in an increase in alkaline phosphatase activity when compared to scrambled control. Conclusions Wnt/β-catenin signaling plays a key role in regulating glucocorticoid-induced osteoporosis in vitro. Silencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation. Targeting of the Wnt/β-catenin signaling pathway offers an exciting opportunity to develop novel anabolic bone agents to treat osteoporosis and disorders of bone mass.-
dc.titleSilencing Dkk1 expression rescues dexamethasone-induced suppression of primary human osteoblast differentiation-
dc.typeJournal Article-
dc.language.rfc3066en-
dc.rights.holderJoseph S Butler et al.; licensee BioMed Central Ltd.-
dc.description.statusPeer Reviewed-
dc.date.updated2012-08-01T03:08:45Z-
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