Format

Send to

Choose Destination
See comment in PubMed Commons below
Bone. 2010 Nov;47(5):926-37. doi: 10.1016/j.bone.2010.08.001. Epub 2010 Aug 7.

AMP kinase acts as a negative regulator of RANKL in the differentiation of osteoclasts.

Author information

1
Asan Institute for Life Sciences, Seoul 138-736, Republic of Korea.

Abstract

INTRODUCTION:

AMP-activated protein kinase (AMPK) has been reported to stimulate differentiation and proliferation of osteoblasts, but the role of AMPK in the physiology of osteoclasts has not been investigated.

METHOD:

Osteoclasts were differentiated from mouse BMMϕs. TRAP-positive multinucleated cells were considered to be osteoclasts using TRAP staining, and resorption area was determined by incubation of cells on dentine discs. Signaling pathways were investigated using Western blotting and RT-PCR.

RESULTS:

RANKL induced phosphorylation/activation of AMPK-α in BMMϕs and stimulated formation of TRAP-positive multinucleated cells. Pharmacological inhibition of AMPK with compound C and siRNA-mediated knockdown of AMPK-α1, the predominant α-subunit isoform in BMMϕs, increased RANKL-induced formation of TRAP-positive multinucleated cells and bone resorption via activation of the downstream signaling elements p38, JNK, NF-κB, Akt, CREB, c-Fos, and NFATc1. STO-609, an inhibitor of CaMKK, completely blocked the RANKL-induced activation of AMPK-α, but KN-93, an inhibitor of CaMK, did not. siRNA-mediated TAK1 knockdown also blocked RANKL-induced activation of AMPK-α. The AMPK activators metformin, (-)-epigallocatechin-3-gallate, berberine, resveratrol, and α-lipoic acid dose-dependently suppressed formation of TRAP-positive multinucleated cells and bone resorption.

CONCLUSION:

AMPK negatively regulates RANKL, possibly by acting through CaMKK and TAK1. Thus, the development of AMPK activators may be a useful strategy for inhibiting the resorption of bone that is stimulated under RANKL-activated conditions.

PMID:
20696287
DOI:
10.1016/j.bone.2010.08.001
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center