Journal
HUMAN MOLECULAR GENETICS
Volume 21, Issue 4, Pages 784-798Publisher
OXFORD UNIV PRESS
DOI: 10.1093/hmg/ddr510
Keywords
-
Funding
- European Commission [MUGEN LSHG-CT-2005-005203, MASTERSWITCH HEALTH-F2-2008-223404]
- Hellenic Ministry for Development [04AKMON72]
- Public Benefit Foundation John S. Latsis [2010-16]
- Deutsche Forschungsgemeinschaft [IMMUNO-BONE SPP1408]
Ask authors/readers for more resources
Receptor activator of nuclear factor-kappa B ligand (RANKL), a trimeric tumor necrosis factor (TNF) superfamily member, is the central mediator of osteoclast formation and bone resorption. Functional mutations in RANKL lead to human autosomal recessive osteopetrosis (ARO), whereas RANKL overexpression has been implicated in the pathogenesis of bone degenerative diseases such as osteoporosis. Following a forward genetics approach using N-ethyl-N-nitrosourea (ENU)-mediated random mutagenesis, we generated a novel mouse model of ARO caused by a new loss-of-function allele of Rankl with a glycine-to-arginine mutation at codon 278 (G278R) at the extracellular inner hydrophobic F beta-strand of RANKL. Mutant mice develop severe osteopetrosis similar to Rankl-deficient mice, whereas exogenous administration of recombinant RANKL restores osteoclast formation in vivo. We show that RANKL(G278R) monomers fail to assemble into homotrimers, are unable to bind and activate the RANK receptor and interact with wild-type RANKL exerting a dominant-negative effect on its trimerization and function in vitro. Since G278 is highly conserved within the TNF superfamily, we identified that a similar substitution in TNF, G122R, also abrogated trimerization, binding to TNF receptor and consequently impaired TNF biological activity. Notably, SPD304, a potent small-molecule inhibitor of TNF trimerization that interacts with G122, also inhibited RANKL activity, suggesting analogous inhibitory mechanisms. Our results provide a new disease model for ARO and identify a functional amino acid in the TNF-like core domain essential for trimer formation both in RANKL and in TNF that could be considered a novel potential target for inhibiting their biological activities.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available