The E3 ligase RNF185 negatively regulates osteogenic differentiation by targeting Dv12 for degradation

Osteoblast plays a pivotal role in bone metabolism and bone remodeling by mediating bone formation and regulating the activity of osteoclast. Clarifying the regulators and regulation mechanisms of osteogenic differentiation of mesenchymal stem cells (MSCs) and pre-osteoblasts will provide tremendous promise for bone repair and bone regeneration. RNF185 was identified as a candidate of endogenous suppressors of osteogenic specification in human mesenchymal stem cells (hMSCs). Here we show that RNF185 down regulates osteogenic differentiation of mouse calvaria-derived MC3T3-E1 cells, confirmed by quantitative real-time-PCR (qRT-PCR) and alkaline phosphatase (ALP) activity. Further we confirm that RNF185 interacts with dishevelled2 (Dv12), a key mediator of Wnt signaling pathway. Overexpression of RNF185 decreases the exogenous and endogenous level of Dv12, promotes the ubiquitination and degradation of Dv12 and inhibits Wnt signaling, which is evident from the down-regulation of beta-catenin mediated transcriptional activity. And Dv12 reverses the effect of RNF185 on osteogenic differentiation of MC3T3-E1 cells. Taken together, our results indicate that RNF185 negatively regulates osteogenesis through the degradation of Dv12 and down-regulation of canonical Wnt signaling pathway and suggest a possible therapeutic target in osteoporosis. (C) 2014 Elsevier Inc. All rights reserved.