Regulator of G protein signaling 12 enhances osteoclastogenesis by suppressing Nrf2-dependent antioxidant proteins to promote the generation of reactive oxygen species

• Published in: eLife Vol. 8
• Main Authors: Ng, Andrew Ying Hui, Li, Ziqing, Jones, Megan M, Yang, Shuting, Li, Chunyi, Fu, Chuanyun, Tu, Chengjian, Oursler, Merry Jo, Qu, Jun, Yang, Shuying
• Format: Journal Article
• Language: English
• Published: England eLife Sciences Publications Ltd 06.09.2019; eLife Sciences Publications, Ltd
• Subjects: Aging; Animals; Antioxidants; Antioxidants - metabolism; Bioinformatics; Bone growth; Bone loss; Bone resorption; Cancellous bone; Cell Biology; Cell differentiation; Clonal deletion; Dentistry; Disease; Gene Expression Regulation; Gene regulation; Kinases; Medical research; Metabolism; Mice; Mice, Inbred C57BL; Mice, Knockout; NF-E2-Related Factor 2 - metabolism; NF-κB protein; Osteoclastogenesis; Osteoclasts; Osteogenesis; Osteoporosis; Osteoprogenitor cells; Oxidative stress; Phenotypes; Phosphorylation; Proteasome 26S; Proteins; Proteomics; RAW 264.7 Cells; Reactive oxygen species; Reactive Oxygen Species - metabolism; Redox properties; RGS Proteins - deficiency; RGS Proteins - metabolism; Signal Transduction; TRANCE protein; Transcription; United States > US; mouse; cell biology; proteomics; osteoclasts; reactive oxygen species
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.42951

Regulators of G-protein Signaling are a conserved family of proteins required in various biological processes including cell differentiation. We previously demonstrated that Rgs12 is essential for osteoclast differentiation and its deletion in vivo protected mice against pathological bone loss. To characterize its mechanism in osteoclastogenesis, we selectively deleted Rgs12 in C57BL/6J mice targeting osteoclast precursors using -driven Cre mice or overexpressed Rgs12 in RAW264.7 cells. Rgs12 deletion in vivo led to an osteopetrotic phenotype evidenced by increased trabecular bone, decreased osteoclast number and activity but no change in osteoblast number and bone formation. Rgs12 overexpression increased osteoclast number and size, and bone resorption activity. Proteomics analysis of Rgs12-depleted osteoclasts identified an upregulation of antioxidant enzymes under the transcriptional regulation of Nrf2, the master regulator of oxidative stress. We confirmed an increase of Nrf2 activity and impaired reactive oxygen species production in Rgs12-deficient cells. Conversely, Rgs12 overexpression suppressed Nrf2 through a mechanism dependent on the 26S proteasome, and promoted RANKL-induced phosphorylation of ERK1/2 and NFκB, which was abrogated by antioxidant treatment. Our study therefore identified a novel role of Rgs12 in regulating Nrf2, thereby controlling cellular redox state and osteoclast differentiation.