ABSTRACT
BACKGROUND: Studies have shown that osteoprotegerin/receptor activator of nuclear factor κB ligand/nuclear factor κB receptor activator (OPG/RANKL/RANK) signaling pathway has a certain correlation with the pathogenesis of giant-cell tumor. Controlling the OPG/RANKL/RANK signaling pathway to affect the interaction between osteoblasts and osteoclasts can play a certain therapeutic role in giant-cell tumor of bone. OBJECTIVE: Ton introduce the relationship between the OPG/RANKL/RANK signaling pathway and the pathogenesis of giant-cell tumor of bone, and to summarize and discuss the new advances of the OPG/RANKL/RANK signaling pathway in the pathogenesis of giant-cell tumor of bone. METHODS: PubMed, Web of Science, and WanFang databases were searched for relevant articles published from 2001 to 2019 using the keywords of “OPG/RANKL/RANK, giant cell tumor of bone, pathogenesis, signal pathway, bone metabolism" in English and Chinese, respectively. A total of 53 articles were finally included for analysis and discussion after removal of old and repeated literatures. RESULTS AND CONCLUSION: OPG inhibits the proliferation and differentiation of osteoclasts, reduces the activity of mature osteoclasts, and blocks the binding of RANKL to RANK. RANKL binds to RANK on the surface of osteoclast progenitor cells to promote the differentiation and proliferation of osteoclast progenitor cells, thus accelerating osteoclast progression. After binding to RANKL receptor, RANKL activates signal factors such as nuclear factor-κB to promote the proliferation, differentiation and activation of osteoclasts, and to regulate the transcription and expression of related genes. Therefore, the OPG/RANKL/RANK is associated with the pathogenesis of giant-cell tumor.
ABSTRACT
Dynamic balance of bone metabolism is one of the important factors to maintain normal osseous tissue function. When the balance is broken, it causes bone damage and even bone metabolic disease. However, the mechanism of bone metabolism is still unclear, the signal pathway is complex, and the treatment of diseases is still under study. The research on the mechanism of bone metabolism by Chinese materia medica has become a new direction in the treatment of bone metabolism diseases. At present, common mechanisms in bone metabolism include OPG/RANKL/RANK signal pathway, Wnt/β-catenin signal pathway, TGF-β/BMP/Smad signal pathway, and NF-κB signal pathway. In this paper, the research on the above pathways was reviewed, so as to provide a reference for further exploring the treatment of bone metabolism diseases with Chinese materia medica.
ABSTRACT
Osteoarthritis (OA) is one of the most common chronic osteoarthritic diseases,which can involve the whole joint.Subchondral bone is an important part of the joint and has a close relationship to the development of OA.The changes and mechanisms of subchondral bone in OA are complex and remain disputes.In this review,we will discuss the advances of the molecular mechanisms of subchondral bone in OA,which include the pathological changes and the roles of the OPG/RANKL/RANK system,transforming growth factor β (TGFβ),estrogen-estrogen receptors and lipid metabolism in OA.
ABSTRACT
Objective To explore the effect of treadmill exercises on disuse osteoporosis and the media effect of OPG-RANKL-RANK system of osteoclast differentiation in the process.Methods Forty six-week-old male Sprague-Dawley rats were randomly divided into a normal control group,a disuse model group,a normal recovery group and an exercise recovery group,each of 10.The normal control group were sacrificed 4 weeks later without receiving any special treatment.The disuse model group were sacrificed after 4 weeks of tail suspension.The normal recovery group were sacrificed after 4 weeks of tail suspension and keeping quiet for 4 weeks.The exercise recovery group were sacrificed after 4 weeks of tail suspension and another 4 weeks of treadmill exercises.The indicators of bone mineral density (BMD),bone histomorphometry,bone tissue TRACP-5b staining,bone metabolism and cytokines related to the osteoclast differentiation OPG-RANKL-RANK system were tested immediately after the rats were sacrificed.Results The BMD,trabecular bone volume percentage (TBV),trabecular bone width (Tb.Wi),concentration of serum alkaline phosphatase (ALP) and the gene expression of bone marrow oculopneumoplethysmograph (OPG) of the disuse model goup were significantly lower than those of the normal control group (P＜0.01),while the trabecular bone spacing (Tb.Sp),average positive staining area percentage (APSAP) of tartrate-resistant acid phosphatase (TRACP)-5b,concentration of serum Ca2+ and TRACP-5b and the gene expression of bone marrow cytokines including RANKL,macrophage colony-stinulating factor (M-CSF),RANK,interleukin (IL)-6 and tumor necrosis factor (TNF)-α of the disuse model goup were significantly higher than those of the normal control group (P＜0.01).The BMD,TBV,Tb.Wi,concentration of serum ALP and the gene expression of bone marrow OPG of the exercise recovery group were significantly higher than those of the normal recovery group (P＜0.05 or P＜0.01).The Tb.Sp,APSAP,concentration of serum Ca2+ and TRACP-5b and the gene expression of RANKL,M-CSF,RANK,IL-6 and TNF-α of the exercise recovery group were significantly lower than those of the normal recovery group (P＜0.05 or P＜0.01).Conclusion The 4-week tail suspension can lead to disuse osteoporosis in rats.Treadmill exercise can promote the recovery of rats with the disuse osteoporosis.The occurrence of disuse osteoporosis and the effect of exercises on disuse osteoporosis were related with the expressing of OPG-RANKL-RANK system-related cytokines of osteoclast differentiation in bone marrow microenvironment.