acid-phosphatase and celastrol

Recently, the traditional Chinese medicine Tripterygium wilfordii Hook f (TwHF) of the Celastraceae family has attracted increasing attention for its potential therapeutic application in patients with rheumatoid arthritis (RA). It is well accepted that TwHF exerts the antirheumatic activity and mainly depends on its potent anti-inflammatory property. To further explore the therapeutic potential of the well-defined TwHF-derived single compound - celastrol in RA, we study the therapeutic efficacy of celastrol on bone erosion in collagen-induced arthritis (CIA) mice and delineate its effects on osteoclast differentiation and functions in RANKL-induced osteoclast precursors RAW264.7 cell line. In CIA mice, daily injection of celastrol (beginning on day 28 after arthritis induction) markedly suppressed arthritis, and reduced bone damage in the joints as demonstrated by histology and bone micro-computed tomography (CT). The effects were accompanied by reductions of osteoclast cells in joints, serum tartrate-resistant acid phosphatase (TRAP) 5b, and expression of osteoclastic genes (Trap, Ctsk, Ctr, Mmp-9) and transcriptional factors (c-Fos, c-Jun and NFATc1). When RAW264.7 cells were treated with RANKL, celastrol inhibited the formation of TRAP+ multinucleated cells and the bone-resorbing activity in dose-dependent manners. Furthermore, celastrol reduced the RANKL-induced expression of osteoclastic genes and transcriptional factors, as well as phosphorylation of NF-kB and mitogen-activated protein kinases (MAPK). These findings show that celastrol could directly inhibit osteoclast formation and function, suggesting a novel therapeutic strategy of celastrol for managing RA, especially in preventing bone destruction.

Topics: Acid Phosphatase; Animals; Arthritis, Experimental; Arthritis, Rheumatoid; Bone Resorption; Cell Differentiation; Cell Line; Gene Expression Regulation; Humans; Isoenzymes; Joints; Medicine, Chinese Traditional; Mice; Mice, Inbred Strains; Osteoclasts; Pentacyclic Triterpenes; RANK Ligand; Tartrate-Resistant Acid Phosphatase; Transcriptional Activation; Tripterygium; Triterpenes

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by bone erosion and cartilage destruction in the joints. Many of the conventional antiarthritic drugs are effective in suppressing inflammation, but they do not offer protection against bone damage. Furthermore, the prolonged use of these drugs is associated with severe adverse reactions. Thus, new therapeutic agents that can control both inflammation and bone damage but with minimal side effects are sought. Celastrus is a Chinese herb that has been used for centuries in folk medicine for the treatment of various inflammatory diseases. However, its utility for protection against inflammation-induced bone damage in arthritis and the mechanisms involved therein have not been examined. We tested celastrus and its bioactive component celastrol for this attribute in the adjuvant-induced arthritis model of RA. The treatment of arthritic rats with celastrus/celastrol suppressed inflammatory arthritis and reduced bone and cartilage damage in the joints as demonstrated by histology and bone histomorphometry. The protective effects against bone damage are mediated primarily via the inhibition of defined mediators of osteoclastic bone remodeling (e.g. receptor activator of nuclear factor-κB ligand (RANKL)), the deviation of RANKL/osteoprotegerin ratio in favor of antiosteoclastic activity, and the reduction in osteoclast numbers. Furthermore, both the upstream inducers (proinflammatory cytokines) and the downstream effectors (MMP-9) of the osteoclastogenic mediators were altered. Thus, celastrus and celastrol controlled inflammation-induced bone damage by modulating the osteoimmune cross-talk. These natural products deserve further consideration and evaluation as adjuncts to conventional therapy for RA.

Topics: 3T3 Cells; Acid Phosphatase; Animals; Arthritis; Autoimmune Diseases; Bone and Bones; Celastrus; Cell Line; Fibroblasts; Immune System; Inflammation; Isoenzymes; Macrophages; Mice; Pentacyclic Triterpenes; Plant Extracts; Rats; Rats, Inbred Lew; Synovial Membrane; Tartrate-Resistant Acid Phosphatase; Triterpenes