title: Sinomenine down-regulates TLR4/TRAF6 expression and attenuates lipopolysaccharide-induced osteoclastogenesis and osteolysis.
abstract: Sinomenine (SIN) is an anti-inflammatory and anti-arthritic alkaloid derived from Sinomenioum acutum. Effects of SIN on lipopolysaccharide (LPS)-induced osteolysis have not been reported. Here, we found that SIN reduced LPS-induced erosion of skull bones in C57BL/6 mice significantly. LPS can induce bone-absorbing osteoclast formation independent of RANKL in pre-osteoclastic RAW264.7 cells in vitro. Here, SIN suppressed LPS-induced osteoclast formation and osteoclast survival in RAW264.7 cells. Expression of osteoclastic-specific marker genes was also inhibited by SIN during osteoclast differentiation and osteoclast survival stimulated with LPS. SIN showed much stronger inhibitory effects on expression of Fra-1 and MMP-9 mRNA in osteoclast differentiation rather than osteoclast survival. SIN dramatically inhibited LPS-induced TNF-α production in vitro and in vivo. Further signaling studies revealed that SIN suppressed the activation and relative gene expression of three notable nuclear factors (NF-κB, AP-1, NFAT), reduced intracellular levels of Ca(2+), and down-regulated phosphorylation of MAPK p38 (but not JNK) in LPS-induced osteoclastogenesis. Focusing on upstream signals after LPS stimulation, SIN decreased expression of TLR4 and TRAF6 during osteoclast differentiation, and reduced expression of TLR4 (but not TRAF6) in osteoclast survival. These data suggest that SIN might be a potential agent for the treatment of osteolysis caused by Gram-negative bacteria infection or inflammation due to its inhibition of osteoclastogenesis through reduction of TLR4/TRAF6 expression and downstream signal transduction.
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China; School of Pharmaceutical Sciences, Fujian Traditional Chinese Medicine University, Fuzhou 350122, China.
authors.forename: Longgang
authors.initials: L
authors.lastname: He
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Duan
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
authors.forename: Xianglian
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Surgery, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou 510120, China.
authors.forename: Song
authors.initials: S
authors.lastname: Wang
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
authors.forename: Yueyang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Lei
authors.affiliation: School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Australia.
authors.forename: Jiake
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China. Electronic address: liusw@smu.edu.cn.
authors.forename: Shuwen
authors.initials: S
authors.lastname: Liu
authors.affiliation: School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China. Electronic address: lixiaoj@smu.edu.cn.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D009019:Morphinans / Q000494:pharmacology* / Q000627:therapeutic use; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism; D010010:Osteoclasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010012:Osteogenesis / Q000187:drug effects*; D010014:Osteolysis / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D000067996:RAW 264.7 Cells; D048029:TNF Receptor-Associated Factor 6 / Q000235:genetics*; D051197:Toll-Like Receptor 4 / Q000235:genetics*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000097:blood / Q000235:genetics
chemical_list: D008070:Lipopolysaccharides; D009019:Morphinans; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D048029:TNF Receptor-Associated Factor 6; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; C009271:sinomenine; D002118:Calcium
keywords: LPS; Osteoclast; Sinomenine; Sinomenine (PubChem CID: 5459308); TLR4; TRAF6