G?13 negatively controls osteoclastogenesis through inhibition of the Akt-GSK3?-NFATc1 signalling pathway.

ABSTRACT: Many positive signalling pathways of osteoclastogenesis have been characterized, but negative signalling pathways are less well studied. Here we show by microarray and RNAi that guanine nucleotide-binding protein subunit ?13 (G?13) is a negative regulator of osteoclastogenesis. Osteoclast-lineage-specific Gna13 conditional knockout mice have a severe osteoporosis phenotype. Gna13-deficiency triggers a drastic increase in both osteoclast number and activity (hyper-activation), mechanistically through decreased RhoA activity and enhanced Akt/GSK3?/NFATc1 signalling. Consistently, Akt inhibition or RhoA activation rescues hyper-activation of Gna13-deficient osteoclasts, and RhoA inhibition mimics the osteoclast hyperactivation resulting from Gna13-deficiency. Notably, G?13 gain-of-function inhibits Akt activation and osteoclastogenesis, and protects mice from pathological bone loss in disease models. Collectively, we reveal that G?13 is a master endogenous negative switch for osteoclastogenesis through regulation of the RhoA/Akt/GSK3?/NFATc1 signalling pathway, and that manipulating G?13 activity might be a therapeutic strategy for bone diseases.

SUBMITTER: Wu M 

PROVIDER: S-EPMC5253683 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature