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Cell Metab. 2015 Nov 3;22(5):811-24. doi: 10.1016/j.cmet.2015.09.010. Epub 2015 Oct 8.

A Liver-Bone Endocrine Relay by IGFBP1 Promotes Osteoclastogenesis and Mediates FGF21-Induced Bone Resorption.

Author information

1
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
2
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address: yihong.wan@utsouthwestern.edu.

Abstract

Fibroblast growth factor 21 (FGF21) promotes insulin sensitivity but causes bone loss. It elevates bone resorption by an undefined non-osteoclast-autonomous mechanism. We have detected a pro-osteoclastogenic activity in the hepatic secretome that is increased by FGF21 and largely attributed to insulin-like growth factor binding protein 1 (IGFBP1). Ex vivo osteoclast differentiation and in vivo bone resorption are both enhanced by recombinant IGFBP1 but suppressed by an IGFBP1-blocking antibody. Anti-IGFBP1 treatment attenuates ovariectomy-induced osteoporosis and abolishes FGF21-induced bone loss while maintaining its insulin-sensitizing metabolic benefit. Mechanistically, IGFBP1 functions via its RGD domain to bind to its receptor integrin β1 on osteoclast precursors, thereby potentiating RANKL-stimulated Erk-phosphorylation and NFATc1 activation. Consequently, osteoclastic integrin β1 deletion confers resistance to the resorption-enhancing effects of both IGFBP1 and FGF21. Therefore, the hepatokine IGFBP1 is a critical liver-bone hormonal relay that promotes osteoclastogenesis and bone resorption as well as an essential mediator of FGF21-induced bone loss.

PMID:
26456333
PMCID:
PMC4635071
DOI:
10.1016/j.cmet.2015.09.010
[Indexed for MEDLINE]
Free PMC Article

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