Dual targeting of SREBP2 and ERRα by carnosic acid suppresses RANKL-mediated osteoclastogenesis and prevents ovariectomy-induced bone loss.

Abstract

Osteoporosis develops because of impaired bone formation and/or excessive bone resorption. Several pharmacological treatment of osteoporosis has been developed; however, new treatments are still necessary. Cholesterol and estrogen receptor-related receptor alpha (ERRα) promote osteoclasts formation, survival, and cellular fusion and thus become high risk factors of osteoporosis. In this study, we identified that carnosic acid (CA) suppressed bone loss by dual-targeting of sterol regulatory element-binding protein 2 (SREBP2, a major regulator that regulates cholesterol synthesis) and ERRα. Mechanistically, CA reduced nuclear localization of mature SREBP2 and suppressed de novo biogenesis of cholesterol. CA subsequently decreased the interaction between ERRα and peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC1β), resulting in decreased the transcription activity of ERRα and its target genes expression. Meanwhile, CA directly bound to the ligand-binding domain of ERRα and significantly promoted its ubiquitination and proteasomal degradation. Subsequently, STUB1 was identified as the E3 ligase of ERRα. The lysine residues (K51 and K68) are essential for ubiquitination and proteasomal degradation of ERRα by CA. In conclusion, CA dually targets SREBP2 and ERRα, thus inhibits the RANKL-induced osteoclast formation and improves OVX-induced bone loss. CA may serve as a lead compound for pharmacological control of osteoporosis.

• Authors: Zu-Guo Zheng, Hui-Min Cheng, Ya-Ping Zhou, Si-Tong Zhu, Pyone Myat Thu, Hui-Jun Li, Ping Li, Xiaojun Xu
• Journal: Cell death and differentiation (Cell Death Differ) Vol. 27 Issue 7 Pg. 2048-2065 (07 2020) ISSN: 1476-5403 [Electronic] England
• PMID: 31907393 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Abietanes
• Nuclear Proteins
• Ppargc1b protein, mouse
• RANK Ligand
• Receptors, Estrogen
• Sterol Regulatory Element Binding Protein 2
• Transcription Factors
• Cholesterol
• Luciferases
• STUB1 protein, human
• Ubiquitin-Protein Ligases
• Tartrate-Resistant Acid Phosphatase
• Proteasome Endopeptidase Complex
• Lysine
• salvin

Topics

• Abietanes (pharmacology)
• Animals
• Bone Resorption (diagnostic imaging, etiology, pathology, prevention & control)
• Cell Differentiation (drug effects)
• Cell Line
• Cholesterol (metabolism)
• Female
• Humans
• Luciferases (metabolism)
• Lysine (metabolism)
• Mice, Inbred C57BL
• Nuclear Proteins (metabolism)
• Osteoclasts (drug effects, metabolism)
• Osteogenesis (drug effects)
• Osteoporosis (blood, diagnostic imaging, etiology)
• Ovariectomy
• Proteasome Endopeptidase Complex (metabolism)
• Proteolysis (drug effects)
• RANK Ligand (pharmacology)
• Receptors, Estrogen (metabolism)
• Sterol Regulatory Element Binding Protein 2 (metabolism)
• Tartrate-Resistant Acid Phosphatase (metabolism)
• Transcription Factors (metabolism)
• Ubiquitin-Protein Ligases
• Ubiquitination (drug effects)
• ERRalpha Estrogen-Related Receptor