Coptisine inhibits RANKL-induced NF-κB phosphorylation in osteoclast precursors and suppresses function through the regulation of RANKL and OPG gene expression in osteoblastic cells
Excessive receptor activator of NF-κB ligand (RANKL) signaling causes enhanced osteoclast formation and bone resorption. The downregulation of RANKL expression and its downstream signals may be an effective therapeutic approach to the treatment of bone loss diseases such as osteoporosis. Here, we found that coptisine, one of the isoquinoline alkaloids from Coptidis Rhizoma, exhibited inhibitory effects on osteoclastogenesis in vitro. Although coptisine has been studied for its antipyretic, antiphotooxidative, dampness dispelling, antidote, antinociceptive, and anti-inflammatory activities in vitro and in vivo, its effects on osteoclastogenesis have not been investigated. Therefore, we evaluated the effects of coptisine on osteoblastic cells as well as osteoclast precursors for osteoclastogenesis in vitro. The addition of coptisine to cocultures of mouse bone marrow cells and primary osteoblastic cells with 10−8 M 1α,25(OH)2D3 caused significant inhibition of osteoclast formation in a dose-dependent manner. Reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed that coptisine inhibited RANKL gene expression and stimulated the osteoprotegerin gene expression induced by 1α,25(OH)2D3 in osteoblastic cells. Coptisine strongly inhibited RANKL-induced osteoclast formation when added during the early stage of bone marrow macrophage (BMM) cultures, suggesting that it acts on osteoclast precursors to inhibit RANKL/RANK signaling. Among the RANK signaling pathways, coptisine inhibited NF-κB p65 phosphorylations, which are regulated in response to RANKL in BMMs. Coptisine also inhibited the RANKL-induced expression of NFATc1, which is a key transcription factor. In addition, 10 μM coptisine significantly inhibited both the survival of mature osteoclasts and their pit-forming activity in cocultures. Thus, coptisine has potential for the treatment or prevention of several bone diseases characterized by excessive bone destruction.
KeywordsCoptisine RANKL Osteoclast NFATc1
This study was supported by a grant for Bio-Defense Programs from the Ministry of Education, Science and Technology (MEST) of the Republic of Korea.
Conflict of interest
The authors have no conflicts of interest.
- 2.Arai F, Miyamoto T, Ohneda O, Inada T, Sudo T, Brasel K, Miyata T, Anderson DM, Suda T (1999) Commitment and differentiation of osteoclast precursor cells by the sequential expression of c-Fms and receptor activator of nuclear factor κB (RANK) receptors. J Exp Med 190:1741–1754PubMedCrossRefGoogle Scholar
- 15.Li HL, Zhang WD, Liu RH, Zhang C, Han T, Wang XW, Wang XL, Zhu JB, Chen CL (2006) Simultaneous determination of four active alkaloids from a traditional Chinese medicine Corydalis saxicola Bunting. (Yanhuanglian) in plasma and urine samples by LC-MS-MS. J Chromatogr B Analyt Technol Biomed Life Sci 831:140–146PubMedCrossRefGoogle Scholar