It has been well documented that exercise can improve bone metabolism, promote bone growth and development, and alleviate bone loss. MicroRNAs (miRNAs) are widely involved in the proliferation and differentiation of bone marrow mesenchymal stem cells, osteoblasts, osteoclasts and other bone tissue cells, and regulation of balance between bone formation and bone resorption by targeting osteogenic factors or bone resorption factors. Thus miRNAs play an important role in the regulation of bone metabolism. Recently, regulation of miRNAs are shown to be one of the ways by which exercise or mechanical stress promotes the positive balance of bone metabolism. Exercise induces changes of miRNAs expression in bone tissue and regulates the expression of related osteogenic factors or bone resorption factors, to further strengthen the osteogenic effect of exercise. This review summarizes relevant studies on the mechanism whereby exercise regulates bone metabolism via miRNAs, providing a theoretical basis for osteoporosis prevention and treatment with exercise.
Humans ; MicroRNAs/metabolism* ; Osteogenesis/genetics* ; Cell Differentiation ; Osteoblasts ; Bone Resorption/metabolism*

Pentaxin 3 (PTX3), as a multifunctional glycoprotein, plays an important role in regulating inflammatory response, promoting tissue repair, inducing ectopic calcification and maintaining bone homeostasis. The effect of PTX3 on bone mineral density (BMD) may be affected by many factors. In PTX3 knockout mice and osteoporosis (OP) patients, the deletion of PTX3 will lead to decrease of BMD. In Korean community "Dong-gu study", it was found that plasma PTX3 was negatively correlated with BMD of femoral neck in male elderly patients. In terms of bone related cells, PTX3 plays an important role in maintaining the phenotype and function of osteoblasts (OB) in OP state;for osteoclast (OC), PTX3 in inflammatory state could stimulate nuclear factor κ receptor activator of nuclear factor-κB ligand (RANKL) production and its combination with TNF-stimulated gene 6(TSG-6) could improve activity of osteoclasts and promote bone resorption;for mesenchymal stem cells (MSCs), PTX3 could promote osteogenic differentiation of MSCs through PI3K/Akt signaling pathway. In recent years, the role of PTX3 as a new bone metabolism regulator in OP and fracture healing has been gradually concerned by scholars. In OP patients, PTX3 regulates bone mass mainly by promoting bone regeneration. In the process of fracture healing, PTX3 promotes fracture healing by coordinating bone regeneration and bone resorption to maintain bone homeostasis. In view of the above biological characteristics, PTX3 is expected to become a new target for the diagnosis and treatment of OP and other age-related bone diseases and fracture healing.
Animals ; Male ; Mice ; Bone Resorption/metabolism* ; Cell Differentiation ; Fracture Healing/genetics* ; Osteoblasts ; Osteoclasts ; Osteogenesis ; Osteoporosis/genetics* ; Phosphatidylinositol 3-Kinases/pharmacology*

The mechanism of Rehmanniae Radix Praeparata against osteoarthritis was investigated based on network pharmacology, molecular docking, and in vitro experiments in the present study. Osteoclast models were established via receptor activator of nuclear factor-κB ligand(RANKL) and macrophage colony-stimulating factor(M-CSF) inducing RAW264.7 cells. Further, the influence of Rehmanniae Radix Praeparata on the activity of tartrate-resistant acid phosphatase(TRAP) was evaluated and the efficacy of Rehmanniae Radix Praeparata in the treatment of osteoarthritis was verified. The active components of Rehmanniae Radix Praeparata were obtained from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP) and literature, and the potential targets of the components were collected from SwissTargetPrediction. Osteoarthritis disease targets were searched in Online Mendelian Inheritance in Man(OMIM), Therapeutic Target Database(TTD), GeneCards, and DisGeNET. The intersection targets of Rehmanniae Radix Praeparata and osteoarthritis were obtained by Venny platform. The protein-protein interaction(PPI) network was constructed by Cytoscape 3.8.2, and key targets were obtained based on topology algorithm. The Database for Annotation, Visualization and Integrated Discovery(DAVID) was used to perform Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis. Finally, the mRNA expression of the key targets was determined by RT-qPCR and the binding activity between the components and key targets was validated by molecular docking. The results showed that Rehmanniae Radix Prae-parata inhibited the TRAP activity, thus inhibiting bone resorption by osteoclasts and treating osteoarthritis. By network pharmacology, 14 active components of Rehmanniae Radix Praeparata and 126 intersection targets were obtained. The network pharmacology enrichment results revealed 432 biological processes and 139 signaling pathways. Key targets such as proto-oncogene tyrosine-protein kinase Src(SRC), signal transducer and activator of transcription 3(STAT3) and transcription factor p65(RELA) were obtained according to the degree in topological analysis. SRC was highly expressed in osteoclasts, which accelerated the development of osteoarthritis. Therefore, SRC was selected for subsequent verification, and Rehmanniae Radix Praeparata decreased the gene expression level of SRC. The molecular docking showed that acteoside, isoacteoside, raffinose had good bonding activity with SRC, suggesting that they might be the critical components in treating osteoarthritis. In conclusion, Rehmanniae Radix Praeparata can inhibit bone resorption by osteoclasts and balance the metabolism of articular cartilage and subchondral bone via acting on SRC, thus playing a therapeutic role in osteoarthritis. In addition, Rehmanniae Radix Praeparata may exert overall efficacy on osteoarthritis through other targets such as STAT3 and RELA, and other related pathways such as PI3 K-AKT and IL-17 signaling pathways.
Humans ; Molecular Docking Simulation ; Network Pharmacology ; Osteoarthritis/genetics* ; Bone Resorption ; Drugs, Chinese Herbal/pharmacology* ; Medicine, Chinese Traditional

Activation of osteoclasts during orthodontic tooth treatment is a prerequisite for alveolar bone resorption and tooth movement. However, the key regulatory molecules involved in osteoclastogenesis during this process remain unclear. Long noncoding RNAs (lncRNAs) are a newly identified class of functional RNAs that regulate cellular processes, such as gene expression and translation regulation. Recently, lncRNAs have been reported to be involved in osteogenesis and bone formation. However, as the most abundant noncoding RNAs in vivo, the potential regulatory role of lncRNAs in osteoclast formation and bone resorption urgently needs to be clarified. We recently found that the lncRNA Nron (long noncoding RNA repressor of the nuclear factor of activated T cells) is highly expressed in osteoclast precursors. Nron is downregulated during osteoclastogenesis and bone ageing. To further determine whether Nron regulates osteoclast activity during orthodontic treatment, osteoclastic Nron transgenic (Nron cTG) and osteoclastic knockout (Nron CKO) mouse models were generated. When Nron was overexpressed, the orthodontic tooth movement rate was reduced. In addition, the number of osteoclasts decreased, and the activity of osteoclasts was inhibited. Mechanistically, Nron controlled the maturation of osteoclasts by regulating NFATc1 nuclear translocation. In contrast, by deleting Nron specifically in osteoclasts, tooth movement speed increased in Nron CKO mice. These results indicate that lncRNAs could be potential targets to regulate osteoclastogenesis and orthodontic tooth movement speed in the clinic in the future.
Animals ; Bone Resorption ; genetics ; Mice ; Mice, Inbred C57BL ; Osteoclasts ; Osteogenesis ; RANK Ligand ; RNA, Long Noncoding ; genetics

Cytokines are believed to be involved in a "vicious circle" of progressive interactions in bone metastasis. Iguratimod is a novel anti-rheumatic drug which is reported to have the capability of anti-cytokines. In this study, a rat model was constructed to investigate the effect of iguratimod on bone metastasis and it was found that iguratimod alleviated cancer-induced bone destruction. To further explore whether an anti-tumor activity of iguratimod contributes to the effect of bone resorption suppression, two human breast cancer cell lines MDA-MB-231 and MCF-7 were studied. The effect of iguratimod on tumor proliferation was detected by CCK-8 assay and flow cytometry. The effects of iguratimod on migration and invasion of cancer cells were determined by wound-healing and Transwell assays. Results showed that high dose (30 μg/mL) iguratimod slightly suppressed the proliferation of cancer cells but failed to inhibit their migration and invasion capacity. Interestingly, iguratimod decreased the transcription level of IL-6 in MDA-MB-231 cells in a concentration-dependent manner. Moreover, iguratimod partially impaired NF-κB signaling by suppressing the phosphorylation of NF-κB p65 subunit. Our findings indicated that iguratimod may alleviate bone destruction by partially decreasing the expression of IL-6 in an NF-κB-dependent manner, while it has little effect on the tumor proliferation and invasion.
Animals ; Apoptosis ; drug effects ; Bone Neoplasms ; complications ; drug therapy ; pathology ; secondary ; Bone Resorption ; complications ; drug therapy ; pathology ; Breast Neoplasms ; complications ; drug therapy ; genetics ; pathology ; Carcinogenesis ; drug effects ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Chromones ; administration & dosage ; Female ; Humans ; Interleukin-6 ; biosynthesis ; genetics ; MCF-7 Cells ; Neoplasm Invasiveness ; genetics ; pathology ; Rats ; Sulfonamides ; administration & dosage ; Transcription Factor RelA ; biosynthesis ; genetics

Adseverin is a Ca2+-dependent actin filament-severing protein that has been reported to regulate exocytosis via rearrangements of the actin cytoskeleton in secretory cells. However, the role of adseverin in bone cells has not yet been well characterized. Here, we investigated the role of adseverin in osteoclastogenesis using primary osteoclast precursor cells. Adseverin expression was upregulated during RANKL (receptor activator of nuclear factor-kappaB ligand)-induced osteoclast differentiation. Moreover, genetic silencing of adseverin decreased the number of osteoclasts generated by RANKL. Adseverin knockdown also suppressed the RANKL-mediated induction of nuclear factor of activated T-cell c1 (NFATc1), which is a key transcription factor in osteoclastogenesis. In addition, adseverin knockdown impaired bone resorption and the secretion of bone-degrading enzymes from osteoclasts. These effects were accompanied by decreased NFATc1 expression and the activation of nuclear factor-kappaB. Collectively, our results indicate that adseverin has a crucial role in osteoclastogenesis by regulating NFATc1.
Active Transport, Cell Nucleus ; Animals ; Bone Resorption/genetics/metabolism/pathology ; Cell Differentiation ; Cells, Cultured ; Female ; Gelsolin/genetics/*metabolism ; Gene Knockdown Techniques ; Humans ; Mice, Inbred ICR ; NF-kappa B/metabolism ; NFATC Transcription Factors/*metabolism ; Osteoclasts/*cytology/metabolism/pathology ; RANK Ligand/*metabolism

This study is to investigate the effect of 8-prenylnaringenin (8-PNG) on osteoclastogensis of bone marrow cells and bone resorption activity of osteoclasts. Osteoclasts were separated from long bone marrow of newborn rabbits and cultured in alpha-MEM containing 10% FBS. 8-PNG was added into culture media at 1 x 10(-7), 1 x 10(-6), 1 x 10(-5) mol xL(-1), separately. 17beta-Estradiol (E2, 1 x 10(-7) mol x L(-7)) was used as positive control. T RAP staining and TRAP activity measurement were performed after 5 days, and the bone resorption pits were analyzed after 7 days. Annexin V staining for the detection of apoptotic osteoclasts was performed after 2, 4, 8, 12, 24, 36 and 48 h separately. The mRNA expression level of TRAP and cathepsin K (CTSK) was measured by real-time RT-PCR. 8-PNG significantly reduced the number of osteoclasts which was TRAP staining positive and with more than three nucleus, the area and number of bone resorption pits decreased obviously in 8-PNG-supplemented groups. The apoptosis rate peaked earlier in the 8-PNG-supplemented groups and the mRNA expression level of TRAP and CTSK decreased significantly. All these inhibitory effects were in a dose dependent manner, the highest effect was obtained by 1 x 10(-5) mol x L(-1) 8-PNG. 8-PNG inhibits bone resorption activity of osteoclasts by inducing osteoclast apoptosis and inhibiting the gene expression and enzyme activity including TRAP and CTSK, and restrains bone marrow cells to osteoclast differentiation.
Acid Phosphatase ; genetics ; metabolism ; Animals ; Apoptosis ; drug effects ; Bone Marrow Cells ; cytology ; Bone Resorption ; Cathepsin K ; genetics ; metabolism ; Cells, Cultured ; Dose-Response Relationship, Drug ; Flavanones ; administration & dosage ; pharmacology ; Isoenzymes ; genetics ; metabolism ; Osteoclasts ; cytology ; metabolism ; RNA, Messenger ; metabolism ; Rabbits ; Tartrate-Resistant Acid Phosphatase

The temporal expression of estrogen receptor (ER)-alpha and ER-beta mRNA was examined in male Japanese quails. Femurs of quails receiving 17beta-estradiol underwent RTPCR and histochemical analysis 1 to 15 days after treatment. Untreated quails were used as controls (day 0). Between days 0 and 5, cells lining the bone endosteal surface differentiated into osteoblasts, which in turn formed medullary bone. Expression of ER-alpha was already observed on day 0 and increased slightly during bone formation whereas ER-beta was hardly detected throughout this process. After osteoclasts appeared on the medullary bone surface, this type of bone disappeared from the bone marrow cavity (days 7~15). ER-alpha expression simultaneously decreased slightly and ER-beta levels remained very low. These results suggest that estrogen activity mediated by ER-alpha not only affects medullary bone formation but also bone resorption.
Animals ; Bone Resorption/genetics ; Bone and Bones/chemistry/cytology/*metabolism ; Cells, Cultured ; Coturnix/*metabolism ; Estradiol/*pharmacology ; Estrogen Receptor alpha/genetics/*metabolism ; Estrogen Receptor beta/genetics/*metabolism ; Gene Expression Regulation ; Male ; Osteoblasts/chemistry/cytology/*metabolism ; Osteogenesis/genetics ; RNA, Messenger/metabolism ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo investigate the effect of osteoclast bone resorption supernatants on the osteogenic activity of mouse MC3T3-E1 cell line.

METHODSMouse RAW264.7 cell line was induced to osteoclast which was identified with tartrate resistant acid phosphatase (TRAP) staining and osteoclast specific gene detection. The differentiated RAW264.7 osteoclast was co-cultured with bovine milling bone specimen followed by toluidine blue staining. Then mouse MC3T3-E1 cell was cultured with supernatant from the osteoclast bone absorbent model. Methyl thiazolyl tetrazolium (MTT) method, alizarin red S staining, enzyme-linked immunosorbent assay detection of osteocalcin, and reverse transcriptase polymerase chain reaction detection were adopted to investigate the proliferation, calcification and osteogenic activity of MC3T3-E1 cells.

RESULTSTRAP staining, osteoclast specific gene detection and toluidine blue staining all indicated that RAW264.7 cell could be differentiated into functioning osteoclast. The supernatant from the osteoclast bone absorbent model could inhibit the proliferation of MC3T3-E1 cells, with the A value between 0.062 ± 0.004 and 0.405 ± 0.033 (P < 0.05). It could also increase the formation of calcification nods, promote the osteocalcin level which peaked with the tenth day's supernatant at a level of (2.965 ± 0.047) µg/L, as well as enhance the transcription of the alkaline phosphatase and Runt related transcription factor 2 gene.

CONCLUSIONSRAW264.7 osteoclast bone absorbent supernatant might influence the osteogenic activity of osteoblast-like cell by inhibiting proliferation, promoting differentiation and calcification.

Acid Phosphatase ; metabolism ; Alkaline Phosphatase ; genetics ; metabolism ; Animals ; Bone Resorption ; Calcification, Physiologic ; Cathepsin K ; metabolism ; Cell Differentiation ; drug effects ; Cell Line ; Cell Proliferation ; drug effects ; Core Binding Factor Alpha 1 Subunit ; genetics ; metabolism ; Culture Media, Conditioned ; pharmacology ; Gene Expression ; Isoenzymes ; metabolism ; Mice ; Osteoblasts ; cytology ; metabolism ; Osteocalcin ; metabolism ; Osteoclasts ; cytology ; enzymology ; Tartrate-Resistant Acid Phosphatase ; Transcription, Genetic

Osteoarthritis (OA) is an age-related joint disease that is characterized by degeneration of articular cartilage and chronic pain. Oxidative stress is considered one of the pathophysiological factors in the progression of OA. We investigated the effects of grape seed proanthocyanidin extract (GSPE), which is an antioxidant, on monosodium iodoacetate (MIA)-induced arthritis of the knee joint of rat, which is an animal model of human OA. GSPE (100 mg/kg or 300 mg/kg) or saline was given orally three times per week for 4 weeks after the MIA injection. Pain was measured using the paw withdrawal latency (PWL), the paw withdrawal threshold (PWT) and the hind limb weight bearing ability. Joint damage was assessed using histological and microscopic analysis and microcomputerized tomography. Matrix metalloproteinase-13 (MMP13) and nitrotyrosine were detected using immunohistochemistry. Administration of GSPE to the MIA-treated rats significantly increased the PWL and PWT and this resulted in recovery of hind paw weight distribution (P < 0.05). GSPE reduced the loss of chondrocytes and proteoglycan, the production of MMP13, nitrotyrosine and IL-1beta and the formation of osteophytes, and it reduced the number of subchondral bone fractures in the MIA-treated rats. These results indicate that GSPE is antinociceptive and it is protective against joint damage in the MIA-treated rat model of OA. GSPE could open up novel avenues for the treatment of OA.
Analgesics/*administration & dosage ; Animals ; Antioxidants/*administration & dosage ; Bone Resorption ; Disease Models, Animal ; Gene Expression Regulation ; Humans ; Interleukin-1beta/genetics/metabolism ; Iodoacetates/administration & dosage ; Knee Joint/*drug effects/metabolism/pathology ; Male ; Matrix Metalloproteinase 13/genetics/metabolism ; Osteoarthritis/chemically induced/*drug therapy/physiopathology ; Pain ; Plant Extracts/administration & dosage ; Proanthocyanidins/*administration & dosage ; Rats ; Rats, Wistar ; Seeds ; Tomography, Emission-Computed ; Tyrosine/analogs & derivatives/metabolism ; Vitis/immunology