Artesunate attenuates LPS-induced osteoclastogenesis by suppressing TLR4/TRAF6 and PLCγ1-Ca2+-NFATc1 signaling pathway

• 来源期刊: 中国药理学报（英文版）
• 关键词: artesunate osteoclast LPS PP2B-Aα Ca2+ NFATc1 TLR4 RAW264.7 cells chronic infectious diseases
• 年，卷（期）: 2020,（2）
• 页码范围: 229-236
• 页数: 8页
• 语种: 英文

摘要

In chronic infectious diseases caused by gram-negative bacteria,such as osteomyelitis,septic arthritis,and periodontitis,osteoclastic activity is enhanced with elevated inflammation,which disturbs the bone homeostasis and results in osteolysis.Lipopolysaccharide (LPS),as a bacteria product,plays an important role in this process.Recent evidence shows that an antimalarial drug artesunate attenuates LPS-induced osteolysis independent of RANKL.In this study we evaluated the effects of artesunate on LPS-induced osteoclastogenesis in vitro and femur osteolysis in vivo,and explored the mechanisms underlying the effects of artesunate on LPS-induced osteoclast differentiation independent of RANKL.In preosteoclastic RAW264.7 cells,we found that artesunate (1.56-12.5 μM) dose dependently inhibited LPS-induced osteoclast formation accompanied by suppressing LPS-stimulated osteoclast-related gene expression (Fra-2,TRAP,Cathepsin K,β3-integrin,DC-STAMP,and Atp6v0d2).We showed that artesunate (3.125-12.5 μM)inhibited LPS-stimulated nuclear factor of activated T cells c1 (NFATc1) but not NF-κB transcriptional activity;artesunate (625,12.5 μM) significantly inhibited LPS-stimulated NFATc1 protein expression.Furthermore,artesunate treatment markedly suppressed LPS-induced Ca2+ influx,and decreased the expression of PP2B-Aα (calcineurin) and pPLCy1 in the cells.In addition,artesunate treatment significantly decreased the expression of upstream signals TLR4 and TRAF6 during LPS-induced osteoclastogenesis.Administration of artesunate (10 mg/kg,ip) for 8 days effectively inhibited serum TNF-α levels and ameliorated LPS (5 mg/kg,iP)-induced inflammatory bone loss in vivo.Taken together,artesunate attenuates LPS-induced inflammatory osteoclastogenesis by inhibiting the expression of TLR4/TRAF6 and the downstream PLCy1-Ca2+-NFATc1 signaling pathway.Artesunate is a valuable choice to treat bone loss induced by gram-negative bacteria infection or inflammation in RANKL-independent pathway.