Type II autosomal dominant osteopetrosis(ADO2), which is the most common form of osteopetrosis, is caused by heterozygous mutations in the chloride channel 7(CLCN7) gene. The osteopetrosis of ADO2 has been attributed ...Type II autosomal dominant osteopetrosis(ADO2), which is the most common form of osteopetrosis, is caused by heterozygous mutations in the chloride channel 7(CLCN7) gene. The osteopetrosis of ADO2 has been attributed to hypofunctional osteoclasts. The mechanism underlying the abnormality in osteoclast function remains largely unknown. This study was designed to investigate gene mutations and osteoclast function in a case that was clinically diagnosed as ADO2. Genomic DNA was extracted from blood samples of this patient, and the 25 exons of CLCN7 were amplified. Peripheral blood from the ADO2 subject and a healthy age- and sex-matched control was used to evaluate osteoclastogenesis, osteoclast morphology, and bone resorption. Analysis of DNA from the patient showed a germline heterozygous missense mutation,c.1856C>T(p.P619L), in exon 20 of CLCN7. A similar homozygous mutation at this site was previously reported in a patient with autosomal recessive osteopetrosis. When cultured, the peripheral blood mononuclear cells(PBMCs) from the ADO2 patient spontaneously differentiated into mature osteoclasts in vitro. The ADO2 patient’s PBMCs formed enhanced, but heterogeneous, osteoclasts in both the presence and absence of macrophage-colony stimulating factor, and nuclear factor-?B ligand. Bone resorption was reduced in the ADO2 patient’s osteoclasts, which exhibited aberrant morphology and abnormal distribution of integrin avβ3. Gene analysis found increased c-fos expression and reduced Rho A and integrin beta 3expression in ADO2 cells. In conclusion, our data suggest that enhanced, heterogeneous osteoclast induction may be an intrinsic characteristic of ADO2.展开更多
Green tea catechin, (–)-epigallocatechin-3-gallate [(–)-EGCG], was found to increase osteogenic functioning in mesenchymal stem cells. This study qualified EGCG, the strongest inhibitory efficiency for receptor acti...Green tea catechin, (–)-epigallocatechin-3-gallate [(–)-EGCG], was found to increase osteogenic functioning in mesenchymal stem cells. This study qualified EGCG, the strongest inhibitory efficiency for receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-activated osteoclastogenesis among other green tea catechins for RAW264, a murine preosteoclast cell line. Moreover, EGCG inhibited tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cell formation dose dependently in both single culture and co-culture systems, the expression of transcription factor, nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) and some osteoclastic genes. Especially, EGCG exhibited a strong inhibitory effect on the expression levels of RANK, the receptor of RANKL, and OSCAR, a key co-stimulator of the RANKL/RANK signal. Simultaneously, apoptotic genes expression and Hoechst staining revealed that EGCG induced apoptosis in RAW264. Taken together, these data suggest that the inhibitory effect of EGCG to osteoclastogenesis is associated with a down regulation of RANKL/RANK signal, and increased apoptosis of preosteoclasts.展开更多
Currently,implant-associated bacterial infections account for most hospital-acquired infections in patients suffering from bone fractures or defects.Poor osseointegration and aggravated osteolysis remain great challen...Currently,implant-associated bacterial infections account for most hospital-acquired infections in patients suffering from bone fractures or defects.Poor osseointegration and aggravated osteolysis remain great challenges for the success of implants in infectious scenarios.Consequently,developing an effective surface modification strategy for implants is urgently needed.Here,a novel nanoplatform(GO/Ga)consisting of graphene oxide(GO)and gallium nanoparticles(GaNPs)was reported,followed by investigations of its in vitro antibacterial activity and potential bacterium inactivation mechanisms,cytocompatibility and regulatory actions on osteoblastogenesis and osteoclastogenesis.In addition,the possible molecular mechanisms underlying the regulatory effects of GO/Ga nanocomposites on osteoblast differentiation and osteoclast formation were clarified.Moreover,an in vivo infectious microenvironment was established in a rat model of implant-related femoral osteomyelitis to determine the therapeutic efficacy and biosafety of GO/Ga nanocomposites.Our results indicate that GO/Ga nanocomposites with excellent antibacterial potency have evident osteogenic potential and inhibitory effects on osteoclast differentiation by modulating the BMP/Smad,MAPK and NF-κB signaling pathways.The in vivo experiments revealed that the administration of GO/Ga nanocomposites significantly inhibited bone infections,reduced osteolysis,promoted osseointegration located in implant-bone interfaces,and resulted in satisfactory biocompatibility.In summary,this synergistic therapeutic system could accelerate the bone healing process in implant-associated infections and can significantly guide the future surface modification of implants used in bacteria-infected environments.展开更多
Background The cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK)...Background The cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK) ligand (RANKL)induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.Methods RAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase (TRAP) staining using a commercial kit. Total ribonucleic acid (RNA)was isolated and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was done to examine the expression of RANK, cathepsin K (CPK) and nuclear factor kappa B (NF-κB). The extracellular signal-regulated kinase (ERK),phosphorylation of ERK (P-ERK) and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.Results AM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of 〉100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.Conclusion AM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.展开更多
Osteoporosis is caused by an osteoclast activation mechanism.People suffering from osteoporosis are prone to bone defects.Increasing evidence indicates that scavenging reactive oxygen species(ROS)can inhibit receptor ...Osteoporosis is caused by an osteoclast activation mechanism.People suffering from osteoporosis are prone to bone defects.Increasing evidence indicates that scavenging reactive oxygen species(ROS)can inhibit receptor activator of nuclear factorκB ligand(RANKL)-induced osteoclastogenesis and suppress ovariectomy-induced osteoporosis.It is critical to develop biomaterials with antioxidant properties to modulate osteoclast activity for treating osteoporotic bone defects.Previous studies have shown that manganese(Mn)can improve bone regeneration,and Mn supplementation may treat osteoporosis.However,the effect of Mn on osteoclasts and the role of Mn in osteoporotic bone defects remain unclear.In present research,a model bioceramic,Mn-containedβ-tricalcium phosphate(Mn-TCP)was prepared by introducing Mn intoβ-TCP.The introduction of Mn intoβ-TCP significantly improved the scavenging of oxygen radicals and nitrogen radicals,demonstrating that Mn-TCP bioceramics might have antioxidant properties.The in vitro and in vivo findings revealed that Mn^(2+)ions released from Mn-TCP bioceramics could distinctly inhibit the formation and function of osteoclasts,promote the differentiation of osteoblasts,and accelerate bone regeneration under osteoporotic conditions in vivo.Mechanistically,Mn-TCP bioceramics inhibited osteoclastogenesis and promoted the regeneration of osteoporotic bone defects by scavenging ROS via Nrf2 activation.These results suggest that Mn-containing bioceramics with osteoconductivity,ROS scavenging and bone resorption inhibition abilities may be an ideal biomaterial for the treatment of osteoporotic bone defect.展开更多
Macrophages and osteoclasts are both derived from monocyte/macrophage lineage,which plays as the osteoclastic part of bone metabolism.Although they are regulated by bone implant surface nanoarchitecture and involved i...Macrophages and osteoclasts are both derived from monocyte/macrophage lineage,which plays as the osteoclastic part of bone metabolism.Although they are regulated by bone implant surface nanoarchitecture and involved in osseointegration,the beneath mechanism has not been simultaneously analyzed in a given surface model and their communication with osteoblasts is also blurring.Here,the effect of implant surface topography on monocyte/macrophage lineage osteoclastogenesis and the subsequent effect on osteogenesis are systematically investigated.The nanoporous surface is fabricated on titanium implant by etching and anodizing to get the nanotubes structure.The early bone formation around implant is significantly accelerated by the nanoporous surface in vivo.Meanwhile,the macrophage recruitment and osteoclast formation are increased and decreased respectively.Mechanistically,the integrin mediated FAK phosphorylation and its downstream MAPK pathway(p-p38)are significantly downregulated by the nanoporous surface,which account for the inhibition of osteoclastogenesis.In addition,the nanoporous surface can alleviate the inhibition of osteoclasts on osteogenesis by changing the secretion of clastokines,and accelerate bone regeneration by macrophage cytokine profiles.In conclusion,these data indicate that physical topography of implant surface is a critical factor modulating monocyte/macrophage lineage commitment,which provides theoretical guidance and mechanism basis for promoting osseointegration by coupling the osteogenesis and osteoclastogenesis.展开更多
Osteoporosis is a reduction in skeletal mass due to the decrease of osteogenic ability and the activation of the osteoclastic function.Inhibiting bone resorption and accelerating the new bone formation is a promising ...Osteoporosis is a reduction in skeletal mass due to the decrease of osteogenic ability and the activation of the osteoclastic function.Inhibiting bone resorption and accelerating the new bone formation is a promising strategy to repair the bone defect of osteoporosis.In this study,we first systematically investigated the roles of Chinese medicine Asperosaponin Ⅵ(ASP Ⅵ)on osteogenic mineralization of BMSCs and osteoclastogenesis of BMMs,and then explored the synergistic effect of ASP Ⅵ and BS(BMP-2 immobilized in 2-N,6-O-sulfated chitosan)on bone formation.The result showed that ASP Ⅵ with the concentration lower than 10^(-4) M contributed to the expression of osteogenic gene and inhibited osteoclastic genes RANKL of BMSCs.Simultaneously,ASP Ⅵ significantly reduced the differentiation of mononuclear osteoclasts in the process of osteoclast formation induced by M-CSF and RANKL.Furthermore,by stimulating the SMADs,TGF-β1,VEGFA,and OPG/RANKL signaling pathways,ASBS(ASP Ⅵ and BS)substantially enhanced osteogenesis,greatly promoted angiogenesis,and suppressed osteoclastogenesis.The findings provide a new perspective on osteoporosis care and prevention.展开更多
We has synthesized the biocompatible gelatin reduced graphene oxide(GOG)in previous research,and in this study we would further evaluate its effects on bone remodeling in the aspects of osteoclastogenesis and angiogen...We has synthesized the biocompatible gelatin reduced graphene oxide(GOG)in previous research,and in this study we would further evaluate its effects on bone remodeling in the aspects of osteoclastogenesis and angiogenesis so as to verify its impact on accelerating orthodontic tooth movement.The mouse orthodontic tooth movement(OTM)model tests in vivo showed that the tooth movement was accelerated in the GOG local injection group with more osteoclastic bone resorption and neovascularization compared with the PBS injection group.The analysis on the degradation of GOG in bone marrow stromal stem cells(BMSCs)illustrated its good biocompatibility in vitro and the accumulation of GOG in spleen after local injection of GOG around the teeth in OTM model in vivo also didn’t influence the survival and life of animals.The co-culture of BMSCs with hematopoietic stem cells(HSCs)or human umbilical vein endothelial cells(HUVECs)in transwell chamber systems were constructed to test the effects of GOG stimulated BMSCs on osteoclastogenesis and angiogenesis in vitro.With the GOG stimulated BMSCs co-culture in upper chamber of transwell,the HSCs in lower chamber manifested the enhanced osteoclastogenesis.Meanwhile,the co-culture of GOG stimulated BMSCs with HUVECs showed a promotive effect on the angiogenic ability of HUVECs.The mechanism analysis on the biofunctions of the GOG stimulated BMSCs illustrated the important regulatory effects of PERK pathway on osteoclastogenesis and angiogenesis.All the results showed the biosecurity of GOG and the biological functions of GOG stimulated BMSCs in accelerating bone remodeling and tooth movement.展开更多
Background: Calpain, a calcium-dependent cysteine protease, has been demonstrated to regulate osteoclastogenesis, which is considered one of the major reasons for cancer-induced bone pain (CIBP). In the present stu...Background: Calpain, a calcium-dependent cysteine protease, has been demonstrated to regulate osteoclastogenesis, which is considered one of the major reasons for cancer-induced bone pain (CIBP). In the present study, calpain inhibitor was applied in a rat CIBP model to determine whether it could reduce CIBP through regulation of osteoclastogenesis activity. Methods: A rat CIBP model was established with intratibial injection of Walker 256 cells. Then, the efficacy of intraperitoneal administered calpain inhibitor III (MDL28170, 1 mg/kg) on mechanical withdrawal threshold (MWT) of bilateral hind paws was examined on postoperative days (PODs) 2, 5, 8, 11, and 14. On POD 14, the calpain inhibitor's effect on tumor bone tartrate-resistant acid phosphatase (TRAP) stain and radiology was also carefully investigated. Results: Pain behavioral tests in rats showed that the calpain inhibitor effectively attenuated MWTs of both the surgical side and contralateral side hind paws on POD 5, 8, and 11 (P 〈 0.05). TRAP-positive cell count of the surgical side bone was significantly decreased in the calpain inhibitor group compared with the vehicle group (P 〈 0.05). However, bone resorption and destruction measured by radiographs showed no difference between the two groups. Conclusions: Calpain inhibitor can effectively reduce CIBP of both the surgical side and nonsurgical side after tumor injection in a rat CIBP model. It may be due to the inhibition of receptor activator of nuclear factor-kappa B ligand-induced osteoclastogenesis. Whether a calpain inhibitor could be a novel therapeutic target to treat CIBP needs further investigation.展开更多
Osteoporosis is a serious public bone metabolic disease. However, the mechanisms underlying bone loss combined with ageing, which is known as senile osteoporosis, remains unknown. Here we show the detailed phenotype o...Osteoporosis is a serious public bone metabolic disease. However, the mechanisms underlying bone loss combined with ageing, which is known as senile osteoporosis, remains unknown. Here we show the detailed phenotype of this disease caused by SIRT6 knock out (KO) in mice. To the best of our knowledge, this is the first study to reveal that SIRT6 is expressed in both bone marrow stroma cells and bone-related cells in both mouse and human models, which suggests that SIRT6 is an important regulator in bone metabolism. SIRT6-KO mice exhibit a significant decrease in body weight and remarkable dwarfism. The skeleton of the SIRT6-KO mouse is deficient in cartilage and mineralized bone tissue. Moreover, the osteocalcin concentration in blood is lower, which suggests that bone mass is markedly lost. Besides, the tartrate-resistant acid phosphatase 5b (TRAP5b) concentration is much higher, which suggests that bone resorption is overactive. Both trabecular and cortical bones exhibit severe osteopenia, and the bone mineral density is decreased. Moreover, double-labelling analysis shows that bone formation is much slower. To determine whether SIRT6 directly regulates bone metabolism, we cultured primary bone marrow stromal cells for osteogenesis and osteoclastogenesis separately to avoid indirect interference in vivo responses such as inflammation. Taken together, these results show that SIRT6 can directly regulate osteoblast proliferation and differentiation, resulting in attenuation in mineralization. Furthermore, SIRT6 can directly regulate osteoclast differentiation and results in a higher number of small osteoclasts, which may be related to overactive bone resorption.展开更多
Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existin...Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that micro RNAs(mi RNAs), known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression,and growing numbers of novel mi RNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis,and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of mi RNAs in regulating bone remodeling as well as novel applications for mi RNAs in biomaterials for therapeutic purposes.展开更多
Orthodontic tooth movement is triggered by orthodontic force loading on the periodontal ligament and is achieved by alveolar bone remodeling,which is regulated by intimate crosstalk between osteoclastogenesis and oste...Orthodontic tooth movement is triggered by orthodontic force loading on the periodontal ligament and is achieved by alveolar bone remodeling,which is regulated by intimate crosstalk between osteoclastogenesis and osteoblast differentiation.Whether the communication between osteoclasts and osteoblasts is influenced by orthodontic compression stress requires further clarification.In this study,osteoclasts were differentiated for 10 days.On day 4 of differentiation,the number of pre-osteoclasts peaked,as determined by the increased expression of RANK and the number of multinucleated cells.After 24 h of compression stress loading,on day 4,the number of osteoclasts increased,and the optimal magnitude of stress to promote osteoclastogenesis was determined as 1 g/cm2.Moreover,the results of RNA-sequencing analysis showed that the miRNA expression profile changed markedly after compression loading and that many of the altered miRNAs were associated with cell communication functions.A series of indirect co-culture experiments showed an inhibitory effect of osteoclasts on osteoblast differentiation,especially after compression.Next,we added osteoclast-derived exosomes to hPDLSCs during osteoblast differentiation.Exosomes derived from osteoclasts under compression(cEXO)showed a greater inhibitory effect on osteoblast differentiation,compared to exosomes from osteoclasts without compression(EXO).Therefore,we analyzed differentially expressed miRNAs associated with bone development functions in exosomes:miR-223-5p and miR-181a-5p were downregulated,whereas miR-133a-3p,miR-203a-3p,miR-106a-5p,and miR-331-3p were upregulated;these altered expressions may explain the enhanced inhibitory effect of compression stress.展开更多
Patients with type 2 diabetes mellitus (T2DM) exhibit hyperglycemia and hyperinsulinemia and increased risk of fracture at early stage, but they were found to have normal or even enhanced bone mineral density (BMD...Patients with type 2 diabetes mellitus (T2DM) exhibit hyperglycemia and hyperinsulinemia and increased risk of fracture at early stage, but they were found to have normal or even enhanced bone mineral density (BMD). This study was aimed to examine the molecular mechanisms governing changes in bone structure and integrity under both hyperglycemic and hyperinsulinemic conditions. Monocytes were isolated from the bone marrow of the C57BL/6 mice, induced to differentiate into os- teoclasts by receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage col- ony-stimulating factor (M-CSF) and exposed to high glucose (33.6 mmol/L), high insulin (1 ~nol/L), or a combination of high glucose/high insulin (33.6 mmol/L glucose and 1 Ixmol/L insulin). Cells cultured in u-MEM alone served as control. After four days of incubation, the cells were harvested and stained for tartrate resistant acid phosphatase (TRAP). Osteoclast-related genes including RANK, cathepsin K and TRAP were determined by using real-time PCR. The resorptive activity of osteoclasts was measured by using a pit formation assay. Osteoclasts that were derived from monocytes were of multinucleated nature and positive for TRAP, a characteristic marker of osteoclasts. Cell counting showed that the number of osteoclasts was much less in high glucose and high glucose/high insulin groups than in nor- mal glucose and high insulin groups. The expression levels of RANK and cathepsin K were signifi- cantly decreased in high glucose, high insulin and high glucose/high insulin groups as compared with normal glucose group, and the TRAP activity was substantially inhibited in high glucose environment. The pit formation assay revealed that the resorptive activity of osteoclasts was obviously decreased in high glucose group and high glucose/high insulin group as compared with normal group. It was concluded that osteoclastogenesis is suppressed under hyperglycemic and hyperinsulinemic conditions, suggesting a disruption of the bone metabolism in diabetic patients.展开更多
A new oxygenated tricyclic cyclopiazonic acid(CPA)alkaloid,asperorydine Q(1),along with seven known compounds,namely,asperorydines O(2)and J(3),speradine H(4),cyclopiamides A(5)and H(6),saadamysin(7),and pyrazinemetha...A new oxygenated tricyclic cyclopiazonic acid(CPA)alkaloid,asperorydine Q(1),along with seven known compounds,namely,asperorydines O(2)and J(3),speradine H(4),cyclopiamides A(5)and H(6),saadamysin(7),and pyrazinemethanol(8),were isolated from the coral-associated Aspergillus flavus GXIMD 02503.The structures were elucidated by physicochemical properties and comprehensive spectroscopic data analysis.Compounds 1−5 and 7−8 exhibited potent inhibition of lipopolysaccharide(LPS)-induced nuclear factor-κB(NF-κB)with the IC50 values ranging from 6.5 to 21.8μmol L^(−1).In addition,the most potent one,pyrazinemethanol(8),dose-dependently suppressed receptor activator of NF-κB ligand(RANKL)-induced osteoclast differentiation without obvious cytotoxicity in bone marrow macrophages cells(BMMCs),suggesting it is a promising lead compound for the treatment of osteolytic diseases.展开更多
Mechanical loading is required for bone homeostasis,but the underlying mechanism is still unclear.Our previous studies revealed that the mechanical protein polycystin-1(PC1,encoded by Pkd1)is critical for bone formati...Mechanical loading is required for bone homeostasis,but the underlying mechanism is still unclear.Our previous studies revealed that the mechanical protein polycystin-1(PC1,encoded by Pkd1)is critical for bone formation.However,the role of PC1 in bone resorption is unknown.Here,we found that PC1directly regulates osteoclastogenesis and bone resorption.The conditional deletion of Pkd1 in the osteoclast lineage resulted in a reduced number of osteoclasts,decreased bone resorption,and increased bone mass.A cohort study of 32,500 patients further revealed that autosomal dominant polycystic kidney disease,which is mainly caused by loss-of-function mutation of the PKD1 gene,is associated with a lower risk of hip fracture than those with other chronic kidney diseases.Moreover,mice with osteoclastspecific knockout of Pkd1 showed complete resistance to unloading-induced bone loss.A mechanistic study revealed that PC1 facilitated TAZ nuclear translocation via the C-terminal tail-TAZ complex and that conditional deletion of Taz in the osteoclast lineage resulted in reduced osteoclastogenesis and increased bone mass.Pharmacological regulation of the PC1-TAZ axis alleviated unloading-and estrogen deficiency-induced bone loss.Thus,the PC1-TAZ axis may be a potential therapeutic target for osteoclast-related osteoporosis.展开更多
Background:Overproduction and activation of osteoclasts result in various bone diseases,such as osteoporosis,Paget's disease,and rheumatoid arthritis.Thus,inhibiting osteoclast formation and overactivation may eff...Background:Overproduction and activation of osteoclasts result in various bone diseases,such as osteoporosis,Paget's disease,and rheumatoid arthritis.Thus,inhibiting osteoclast formation and overactivation may effectively prevent osteoclast-related bone diseases,especially osteoporosis.Madecassic acid,one of the most important active ingredients in Centella asiatica,has various biological effects,but its role in osteoclastogenesis remains unknown.Methods:RAW 264.7 cells were stimulated with receptor activator of nuclear factor(NF)-κΒligand(RANKL,25 ng/mL)to differentiate into multinucleated osteoclasts.Subsequently,osteoclasts were treated with or without varying concentrations of madecassic acid(1,2.5,5,and 10μmol/L).Results:Madecassic acid significantly inhibited RANKL-induced osteoclastogenesis in a concentration-dependent manner.In addition,it reduced the percentage of bone resorptive area compared with the control,confirming that madecassic acid can inhibit osteoclast function.Furthermore,luciferase reporter gene studies indicate that madecassic acid could decrease the transcriptional activity of NF of activated T cells(NFAT)and NF-κB in a dose-dependent manner.Quantitative real-time polymerase chain reaction results show that madecassic acid attenuated the expression of osteoclast-associated genes,including V-ATPase-d2,cathepsin K,tartrate-resistant acid phosphatase(TRAP),NFAT cytoplasmic 1(NFATc1).Western blot analysis shows that madecassic acid inhibited RANKL-mediated degradation of IκBαand NFATc1 expression,as well as phosphorylation of c-Jun N-terminal kinase(JNK)in RAW 264.7 cells.Conclusion:Madecassic acid inhibited osteoclast formation and function in vitro by suppressing NF-κB,JNK,and NFAT signaling pathways,indicating its potential as a novel drug for the treatment of osteoclast-related bone diseases,especially osteoporosis.展开更多
Rapid progress has been made in exploring the connections between the skeletal system and the immune system over the past decade. Bone tissue forms developmental niches for hematopoietic stem cells, and activated immu...Rapid progress has been made in exploring the connections between the skeletal system and the immune system over the past decade. Bone tissue forms developmental niches for hematopoietic stem cells, and activated immune cells are involved in bone metabolism regulation and are potent mediators of osteoporosis and bone erosion under pathological conditions. The interdisciplinary field of osteoimmunology has emerged to pool the knowledge of the interdependence of these two systems, including the shared ligands and receptors, their crosstalk and interaction, and common intracellular signaling pathways with bidirectional influence. The receptor activator of nuclear factor-kappa B(RANK)/RANK ligand(RANKL)/osteoprotegerin(OPG) triad is the key vinculum, with multifaceted potency, being not only essential for osteoclastogenesis but also critical for lymph node organogenesis and lymphopoiesis as well as for immune regulation. In this review, we summarize the progress in this area, focusing on those aspects of interest concerning rheumatic diseases.展开更多
Bone tissue regeneration in critical-size defects is possible after implantation of a 3D scaffold and can be additionally enhanced once the scaffold is enriched with drugs or other factors supporting bone remodelling ...Bone tissue regeneration in critical-size defects is possible after implantation of a 3D scaffold and can be additionally enhanced once the scaffold is enriched with drugs or other factors supporting bone remodelling and healing.Sodium alendronate(Aln),a widely used anti-osteoporosis drug,exhibits strong inhibitory effect on bone resorption performed by osteoclasts.Thus,we propose a new approach for the treatment of bone defects in craniofacial region combining biocompatible titanium dioxide scaffolds and poly(L-lactide-co-glycolide)microparticles(MPs)loaded with Aln.The MPs were effectively attached to the surface of the scaffolds’pore walls by human recombinant collagen.Drug release from the scaffolds was characterized by initial burst(2466% of the drug released within first 24 h)followed by a sustained release phase(on average 5 mg of Aln released per day from Day 3 to Day 18).In vitro tests evidenced that Aln at concentrations of 5 and 2.5 mg/ml was not cytotoxic for MG-63 osteoblast-like cells(viability between 8166% and 9863% of control),but it prevented RANKL-induced formation of osteoclast-like cells from macrophages derived from peripheral blood mononuclear cells,as shown by reduced fusion capability and decreased tartrateresistant acid phosphatase 5b activity(5665% reduction in comparison to control after 8 days of culture).Results show that it is feasible to design the scaffolds providing required doses of Aln inhibiting osteoclastogenesis,reducing osteoclast activity,but not affecting osteoblast functions,which may be beneficial in the treatment of critical-size bone tissue defects.展开更多
Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement.Compression stress also stimulates angiogenesis,which is essential for osteoclastogenesis.However,the effects of os...Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement.Compression stress also stimulates angiogenesis,which is essential for osteoclastogenesis.However,the effects of osteoclastogenesis induced by compression on angiogenesis are poorly understood.In vivo,we found the markers of angiogenesis increased during orthodontic bone remodeling.In vitro,osteoclast-derived exosomes increased proliferation,migration,and tube formation of human umbilical vein endothelial cells(HUVECs),as well as expression of vascular endothelial growth factor and CD31.The promotive effects of exosomes derived from compressed osteoclasts were greater than those derived from osteoclasts without compression.Next,we analyzed changes in the micro RNA transcriptome after compression stress and focused on micro RNA146 a-5 p(mi R-146 a),which was significantly decreased by compression.Transfection of an inhibitor of mi R-146 a stimulated angiogenesis of HUVECs while mi R-146 a mimics repressed angiogenesis.Adiponectin(ADP)was confirmed to be a target of mi R-146 a by dual luciferase reporter assay.In HUVECs treated with exosomes,we detected increased ADP which promoted angiogenesis.Knockdown of ADP in HUVECs reduced the promotive effects of exosomes.Our results demonstrate that the decreased mi R-146 a observed in osteoclasts after compression promotes angiogenesis by targeting ADP,suggesting a novel method to interfere with bone remodeling induced by compression stress.展开更多
Strontium-substituted bioactive glass(Sr-BG)has shown superior performance in bone regeneration.Sr-BG-induced osteogenesis has been extensively studied;however,Sr-BG-mediated osteoclastogenesis and the underlying mole...Strontium-substituted bioactive glass(Sr-BG)has shown superior performance in bone regeneration.Sr-BG-induced osteogenesis has been extensively studied;however,Sr-BG-mediated osteoclastogenesis and the underlying molecular mechanism remain unclear.It is recognized that the balance of osteogenesis and osteoclastogenesis is closely related to bone repair,and the receptor activators of nuclear factor kappaB ligand(RANKL)signaling pathway plays a key role of in the regulation of osteoclastogenesis.Herein,we studied the potential impact and underling mechanism of strontium-substituted sub-micron bioactive glass(Sr-SBG)on RANKL-induced osteoclast activation and differentiation in vitro.As expected,Sr-SBG inhibited RANKL-mediated osteoclastogenesis significantly with the experimental performance of decreased mature osteoclasts formation and downregulation of osteoclastogenesis-related gene expression.Furthermore,it was found that Sr-SBG might suppress osteoclastogenesis by the combined effect of strontium and silicon released through inhibition of RANKL-induced activation of p38 and NF-κB pathway.These results elaborated the effect of Sr-SBG-based materials on osteoclastogenesis through RANKLinduced downstream pathway and might represent a significant guidance for designing better bone repair materials.展开更多
基金supported by grants from the National Natural Science Foundation of China(Nos.81572639,81370969 and 81072190 to X Yu)the Ministry of Education of the People's Republic of China(No.20130181110066 to X Yu)the Chengdu Bureau of Science and Technology(No.2014-HM01-00382-SF to X Yu)
文摘Type II autosomal dominant osteopetrosis(ADO2), which is the most common form of osteopetrosis, is caused by heterozygous mutations in the chloride channel 7(CLCN7) gene. The osteopetrosis of ADO2 has been attributed to hypofunctional osteoclasts. The mechanism underlying the abnormality in osteoclast function remains largely unknown. This study was designed to investigate gene mutations and osteoclast function in a case that was clinically diagnosed as ADO2. Genomic DNA was extracted from blood samples of this patient, and the 25 exons of CLCN7 were amplified. Peripheral blood from the ADO2 subject and a healthy age- and sex-matched control was used to evaluate osteoclastogenesis, osteoclast morphology, and bone resorption. Analysis of DNA from the patient showed a germline heterozygous missense mutation,c.1856C>T(p.P619L), in exon 20 of CLCN7. A similar homozygous mutation at this site was previously reported in a patient with autosomal recessive osteopetrosis. When cultured, the peripheral blood mononuclear cells(PBMCs) from the ADO2 patient spontaneously differentiated into mature osteoclasts in vitro. The ADO2 patient’s PBMCs formed enhanced, but heterogeneous, osteoclasts in both the presence and absence of macrophage-colony stimulating factor, and nuclear factor-?B ligand. Bone resorption was reduced in the ADO2 patient’s osteoclasts, which exhibited aberrant morphology and abnormal distribution of integrin avβ3. Gene analysis found increased c-fos expression and reduced Rho A and integrin beta 3expression in ADO2 cells. In conclusion, our data suggest that enhanced, heterogeneous osteoclast induction may be an intrinsic characteristic of ADO2.
文摘Green tea catechin, (–)-epigallocatechin-3-gallate [(–)-EGCG], was found to increase osteogenic functioning in mesenchymal stem cells. This study qualified EGCG, the strongest inhibitory efficiency for receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-activated osteoclastogenesis among other green tea catechins for RAW264, a murine preosteoclast cell line. Moreover, EGCG inhibited tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cell formation dose dependently in both single culture and co-culture systems, the expression of transcription factor, nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) and some osteoclastic genes. Especially, EGCG exhibited a strong inhibitory effect on the expression levels of RANK, the receptor of RANKL, and OSCAR, a key co-stimulator of the RANKL/RANK signal. Simultaneously, apoptotic genes expression and Hoechst staining revealed that EGCG induced apoptosis in RAW264. Taken together, these data suggest that the inhibitory effect of EGCG to osteoclastogenesis is associated with a down regulation of RANKL/RANK signal, and increased apoptosis of preosteoclasts.
基金Our study was financially supported by the National Natural Science Fundation for Youth of China(Nos.81802136)the Natural Science Fundation for Youth of Hunan Province(Nos.2020JJ5939)+2 种基金the Postdoctoral Science Fundation of China(Nos.2018M643005)the National Natural Science Fundation of China(Nos.52172265)the Science Fundation for Youth of Xiangya Hospital,Central South University(Nos.2017Q18).
文摘Currently,implant-associated bacterial infections account for most hospital-acquired infections in patients suffering from bone fractures or defects.Poor osseointegration and aggravated osteolysis remain great challenges for the success of implants in infectious scenarios.Consequently,developing an effective surface modification strategy for implants is urgently needed.Here,a novel nanoplatform(GO/Ga)consisting of graphene oxide(GO)and gallium nanoparticles(GaNPs)was reported,followed by investigations of its in vitro antibacterial activity and potential bacterium inactivation mechanisms,cytocompatibility and regulatory actions on osteoblastogenesis and osteoclastogenesis.In addition,the possible molecular mechanisms underlying the regulatory effects of GO/Ga nanocomposites on osteoblast differentiation and osteoclast formation were clarified.Moreover,an in vivo infectious microenvironment was established in a rat model of implant-related femoral osteomyelitis to determine the therapeutic efficacy and biosafety of GO/Ga nanocomposites.Our results indicate that GO/Ga nanocomposites with excellent antibacterial potency have evident osteogenic potential and inhibitory effects on osteoclast differentiation by modulating the BMP/Smad,MAPK and NF-κB signaling pathways.The in vivo experiments revealed that the administration of GO/Ga nanocomposites significantly inhibited bone infections,reduced osteolysis,promoted osseointegration located in implant-bone interfaces,and resulted in satisfactory biocompatibility.In summary,this synergistic therapeutic system could accelerate the bone healing process in implant-associated infections and can significantly guide the future surface modification of implants used in bacteria-infected environments.
基金This work was supported by the grants from Jiangsu Province Key Medical Center (No. ZX200608), the National Nature Science Foundation of China (No. 30672140, No. 81071451), the Colleges and Universities Natural Science Foundation in Jiangsu Province (No. 10KJB320019), the Key Project Surpported by the Medical Science and Technology Department Foundation, Jiangsu Province, Department of Health (No. H201012) and the Social Development Projects in Suzhou (No. SS08020).
文摘Background The cannabinoid receptor-2 (CB2) is important for bone remodeling. In this study, we investigated the effects of CB2 selective antagonist (AM630) on receptor activator of nuclear factor kappa B (RANK) ligand (RANKL)induced osteoclast differentiation and the underlying signaling pathway using a monocyte-macrophage cell line-RAW264.7.Methods RAW264.7 was cultured with RANKL for 6 days and then treated with AM630 for 24 hours. Mature osteoclasts were measured by tartrate-resistant acid phosphatase (TRAP) staining using a commercial kit. Total ribonucleic acid (RNA)was isolated and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was done to examine the expression of RANK, cathepsin K (CPK) and nuclear factor kappa B (NF-κB). The extracellular signal-regulated kinase (ERK),phosphorylation of ERK (P-ERK) and NF-κB production were tested by Western blotting. The effect of AM630 on RAW264.7 viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.Results AM630 did not affect the viability of RAW264.7. However, this CB2 selective antagonist markedly inhibited osteoclast formation and the inhibition rate was dose-dependent. The dose of 〉100 nmol/L could reduce TRAP positive cells to the levels that were significantly lower than the control. AM630 suppressed the expression of genes associated with osteoclast differentiation and activation, such as RANK and CPK. An analysis of a signaling pathway showed that AM630 inhibited the RANKL-induced activation of ERK, but not NF-κB.Conclusion AM630 could inhibit the osteoclastogenesis from RAW264.7 induced with RANKL.
基金the Key Program of National Natural Science Foundation of China(81930067)the Youth Program of National Natural Science Foundation of China(grant number 82002316)+1 种基金the Youth Cultivation Project of Army Medical University(2020XQN08)General Program of Natural Science Foundation of Chongqing(cstc2019jcyj-msxmX0176).
文摘Osteoporosis is caused by an osteoclast activation mechanism.People suffering from osteoporosis are prone to bone defects.Increasing evidence indicates that scavenging reactive oxygen species(ROS)can inhibit receptor activator of nuclear factorκB ligand(RANKL)-induced osteoclastogenesis and suppress ovariectomy-induced osteoporosis.It is critical to develop biomaterials with antioxidant properties to modulate osteoclast activity for treating osteoporotic bone defects.Previous studies have shown that manganese(Mn)can improve bone regeneration,and Mn supplementation may treat osteoporosis.However,the effect of Mn on osteoclasts and the role of Mn in osteoporotic bone defects remain unclear.In present research,a model bioceramic,Mn-containedβ-tricalcium phosphate(Mn-TCP)was prepared by introducing Mn intoβ-TCP.The introduction of Mn intoβ-TCP significantly improved the scavenging of oxygen radicals and nitrogen radicals,demonstrating that Mn-TCP bioceramics might have antioxidant properties.The in vitro and in vivo findings revealed that Mn^(2+)ions released from Mn-TCP bioceramics could distinctly inhibit the formation and function of osteoclasts,promote the differentiation of osteoblasts,and accelerate bone regeneration under osteoporotic conditions in vivo.Mechanistically,Mn-TCP bioceramics inhibited osteoclastogenesis and promoted the regeneration of osteoporotic bone defects by scavenging ROS via Nrf2 activation.These results suggest that Mn-containing bioceramics with osteoconductivity,ROS scavenging and bone resorption inhibition abilities may be an ideal biomaterial for the treatment of osteoporotic bone defect.
基金supported by National Natural Science Foundation of China(81530051,31800790 and 32071324)Young Talent Fund of University Association for Science and Technology in Shaanxi,China(20190304).
文摘Macrophages and osteoclasts are both derived from monocyte/macrophage lineage,which plays as the osteoclastic part of bone metabolism.Although they are regulated by bone implant surface nanoarchitecture and involved in osseointegration,the beneath mechanism has not been simultaneously analyzed in a given surface model and their communication with osteoblasts is also blurring.Here,the effect of implant surface topography on monocyte/macrophage lineage osteoclastogenesis and the subsequent effect on osteogenesis are systematically investigated.The nanoporous surface is fabricated on titanium implant by etching and anodizing to get the nanotubes structure.The early bone formation around implant is significantly accelerated by the nanoporous surface in vivo.Meanwhile,the macrophage recruitment and osteoclast formation are increased and decreased respectively.Mechanistically,the integrin mediated FAK phosphorylation and its downstream MAPK pathway(p-p38)are significantly downregulated by the nanoporous surface,which account for the inhibition of osteoclastogenesis.In addition,the nanoporous surface can alleviate the inhibition of osteoclasts on osteogenesis by changing the secretion of clastokines,and accelerate bone regeneration by macrophage cytokine profiles.In conclusion,these data indicate that physical topography of implant surface is a critical factor modulating monocyte/macrophage lineage commitment,which provides theoretical guidance and mechanism basis for promoting osseointegration by coupling the osteogenesis and osteoclastogenesis.
基金funded by National Key Research and Development Program of China(No.2016YFC1102900)National Natural Science Foundation of China(No.51772100 and No.32171342)+2 种基金Shanghai Science and Technology Agriculture Project(No.202002080002F01474)Shanghai Pujiang Program(16PJD015)Joint Fund for equipment pre-research of the ministry of education(6141A02022618).
文摘Osteoporosis is a reduction in skeletal mass due to the decrease of osteogenic ability and the activation of the osteoclastic function.Inhibiting bone resorption and accelerating the new bone formation is a promising strategy to repair the bone defect of osteoporosis.In this study,we first systematically investigated the roles of Chinese medicine Asperosaponin Ⅵ(ASP Ⅵ)on osteogenic mineralization of BMSCs and osteoclastogenesis of BMMs,and then explored the synergistic effect of ASP Ⅵ and BS(BMP-2 immobilized in 2-N,6-O-sulfated chitosan)on bone formation.The result showed that ASP Ⅵ with the concentration lower than 10^(-4) M contributed to the expression of osteogenic gene and inhibited osteoclastic genes RANKL of BMSCs.Simultaneously,ASP Ⅵ significantly reduced the differentiation of mononuclear osteoclasts in the process of osteoclast formation induced by M-CSF and RANKL.Furthermore,by stimulating the SMADs,TGF-β1,VEGFA,and OPG/RANKL signaling pathways,ASBS(ASP Ⅵ and BS)substantially enhanced osteogenesis,greatly promoted angiogenesis,and suppressed osteoclastogenesis.The findings provide a new perspective on osteoporosis care and prevention.
基金funded by China Postdoctoral Science Foundation(2021M692249)National Key R&D Program of China 2017YFC1104304(YB)+1 种基金National Natural Science Foundation of China grant 82071144,Shanghai Rising-Star Program(21QA1405400)Innovative research team of high-level local universities in Shanghai(SSMU-ZDCX20180900).
文摘We has synthesized the biocompatible gelatin reduced graphene oxide(GOG)in previous research,and in this study we would further evaluate its effects on bone remodeling in the aspects of osteoclastogenesis and angiogenesis so as to verify its impact on accelerating orthodontic tooth movement.The mouse orthodontic tooth movement(OTM)model tests in vivo showed that the tooth movement was accelerated in the GOG local injection group with more osteoclastic bone resorption and neovascularization compared with the PBS injection group.The analysis on the degradation of GOG in bone marrow stromal stem cells(BMSCs)illustrated its good biocompatibility in vitro and the accumulation of GOG in spleen after local injection of GOG around the teeth in OTM model in vivo also didn’t influence the survival and life of animals.The co-culture of BMSCs with hematopoietic stem cells(HSCs)or human umbilical vein endothelial cells(HUVECs)in transwell chamber systems were constructed to test the effects of GOG stimulated BMSCs on osteoclastogenesis and angiogenesis in vitro.With the GOG stimulated BMSCs co-culture in upper chamber of transwell,the HSCs in lower chamber manifested the enhanced osteoclastogenesis.Meanwhile,the co-culture of GOG stimulated BMSCs with HUVECs showed a promotive effect on the angiogenic ability of HUVECs.The mechanism analysis on the biofunctions of the GOG stimulated BMSCs illustrated the important regulatory effects of PERK pathway on osteoclastogenesis and angiogenesis.All the results showed the biosecurity of GOG and the biological functions of GOG stimulated BMSCs in accelerating bone remodeling and tooth movement.
基金This study was funded by Beijing Natural Science Foundation
文摘Background: Calpain, a calcium-dependent cysteine protease, has been demonstrated to regulate osteoclastogenesis, which is considered one of the major reasons for cancer-induced bone pain (CIBP). In the present study, calpain inhibitor was applied in a rat CIBP model to determine whether it could reduce CIBP through regulation of osteoclastogenesis activity. Methods: A rat CIBP model was established with intratibial injection of Walker 256 cells. Then, the efficacy of intraperitoneal administered calpain inhibitor III (MDL28170, 1 mg/kg) on mechanical withdrawal threshold (MWT) of bilateral hind paws was examined on postoperative days (PODs) 2, 5, 8, 11, and 14. On POD 14, the calpain inhibitor's effect on tumor bone tartrate-resistant acid phosphatase (TRAP) stain and radiology was also carefully investigated. Results: Pain behavioral tests in rats showed that the calpain inhibitor effectively attenuated MWTs of both the surgical side and contralateral side hind paws on POD 5, 8, and 11 (P 〈 0.05). TRAP-positive cell count of the surgical side bone was significantly decreased in the calpain inhibitor group compared with the vehicle group (P 〈 0.05). However, bone resorption and destruction measured by radiographs showed no difference between the two groups. Conclusions: Calpain inhibitor can effectively reduce CIBP of both the surgical side and nonsurgical side after tumor injection in a rat CIBP model. It may be due to the inhibition of receptor activator of nuclear factor-kappa B ligand-induced osteoclastogenesis. Whether a calpain inhibitor could be a novel therapeutic target to treat CIBP needs further investigation.
基金supported by NSFC grants 81371136 and JCPT2011-9 (Xue-Dong Zhou),NSFC grants 81470711 and 81200760 (Li-Wei Zheng)Ling Ye (Professor, Sate Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University) for financial aid
文摘Osteoporosis is a serious public bone metabolic disease. However, the mechanisms underlying bone loss combined with ageing, which is known as senile osteoporosis, remains unknown. Here we show the detailed phenotype of this disease caused by SIRT6 knock out (KO) in mice. To the best of our knowledge, this is the first study to reveal that SIRT6 is expressed in both bone marrow stroma cells and bone-related cells in both mouse and human models, which suggests that SIRT6 is an important regulator in bone metabolism. SIRT6-KO mice exhibit a significant decrease in body weight and remarkable dwarfism. The skeleton of the SIRT6-KO mouse is deficient in cartilage and mineralized bone tissue. Moreover, the osteocalcin concentration in blood is lower, which suggests that bone mass is markedly lost. Besides, the tartrate-resistant acid phosphatase 5b (TRAP5b) concentration is much higher, which suggests that bone resorption is overactive. Both trabecular and cortical bones exhibit severe osteopenia, and the bone mineral density is decreased. Moreover, double-labelling analysis shows that bone formation is much slower. To determine whether SIRT6 directly regulates bone metabolism, we cultured primary bone marrow stromal cells for osteogenesis and osteoclastogenesis separately to avoid indirect interference in vivo responses such as inflammation. Taken together, these results show that SIRT6 can directly regulate osteoblast proliferation and differentiation, resulting in attenuation in mineralization. Furthermore, SIRT6 can directly regulate osteoclast differentiation and results in a higher number of small osteoclasts, which may be related to overactive bone resorption.
基金supported by grants from the Science and Technology Fund of Sichuan Province (Grant No. 2011SZ0096)the National Natural Science Foundation of China (Grant No. 31470904)
文摘Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that micro RNAs(mi RNAs), known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression,and growing numbers of novel mi RNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis,and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of mi RNAs in regulating bone remodeling as well as novel applications for mi RNAs in biomaterials for therapeutic purposes.
基金This work was supported by grants from the National Natural Science Foundation of China(Nos.81700938,81670957).
文摘Orthodontic tooth movement is triggered by orthodontic force loading on the periodontal ligament and is achieved by alveolar bone remodeling,which is regulated by intimate crosstalk between osteoclastogenesis and osteoblast differentiation.Whether the communication between osteoclasts and osteoblasts is influenced by orthodontic compression stress requires further clarification.In this study,osteoclasts were differentiated for 10 days.On day 4 of differentiation,the number of pre-osteoclasts peaked,as determined by the increased expression of RANK and the number of multinucleated cells.After 24 h of compression stress loading,on day 4,the number of osteoclasts increased,and the optimal magnitude of stress to promote osteoclastogenesis was determined as 1 g/cm2.Moreover,the results of RNA-sequencing analysis showed that the miRNA expression profile changed markedly after compression loading and that many of the altered miRNAs were associated with cell communication functions.A series of indirect co-culture experiments showed an inhibitory effect of osteoclasts on osteoblast differentiation,especially after compression.Next,we added osteoclast-derived exosomes to hPDLSCs during osteoblast differentiation.Exosomes derived from osteoclasts under compression(cEXO)showed a greater inhibitory effect on osteoblast differentiation,compared to exosomes from osteoclasts without compression(EXO).Therefore,we analyzed differentially expressed miRNAs associated with bone development functions in exosomes:miR-223-5p and miR-181a-5p were downregulated,whereas miR-133a-3p,miR-203a-3p,miR-106a-5p,and miR-331-3p were upregulated;these altered expressions may explain the enhanced inhibitory effect of compression stress.
基金supported by the National Natural Science Foundation of China(No.81070691)
文摘Patients with type 2 diabetes mellitus (T2DM) exhibit hyperglycemia and hyperinsulinemia and increased risk of fracture at early stage, but they were found to have normal or even enhanced bone mineral density (BMD). This study was aimed to examine the molecular mechanisms governing changes in bone structure and integrity under both hyperglycemic and hyperinsulinemic conditions. Monocytes were isolated from the bone marrow of the C57BL/6 mice, induced to differentiate into os- teoclasts by receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage col- ony-stimulating factor (M-CSF) and exposed to high glucose (33.6 mmol/L), high insulin (1 ~nol/L), or a combination of high glucose/high insulin (33.6 mmol/L glucose and 1 Ixmol/L insulin). Cells cultured in u-MEM alone served as control. After four days of incubation, the cells were harvested and stained for tartrate resistant acid phosphatase (TRAP). Osteoclast-related genes including RANK, cathepsin K and TRAP were determined by using real-time PCR. The resorptive activity of osteoclasts was measured by using a pit formation assay. Osteoclasts that were derived from monocytes were of multinucleated nature and positive for TRAP, a characteristic marker of osteoclasts. Cell counting showed that the number of osteoclasts was much less in high glucose and high glucose/high insulin groups than in nor- mal glucose and high insulin groups. The expression levels of RANK and cathepsin K were signifi- cantly decreased in high glucose, high insulin and high glucose/high insulin groups as compared with normal glucose group, and the TRAP activity was substantially inhibited in high glucose environment. The pit formation assay revealed that the resorptive activity of osteoclasts was obviously decreased in high glucose group and high glucose/high insulin group as compared with normal group. It was concluded that osteoclastogenesis is suppressed under hyperglycemic and hyperinsulinemic conditions, suggesting a disruption of the bone metabolism in diabetic patients.
基金supported by the Natural Science Foundation of Guangxi(No.2020GXNSFGA297002)the Specific Research Project of Guangxi for Research Bases and Talents(No.AD20297003)+3 种基金the Special Fund for Bagui Scholars of Guangxi(Y.Liu)the National Natural Science Foundation of China(Nos.U20A20101,22007019)the Key State Laboratory Talent Project of Guangxi Normal University(No.CMEMR 2019-A05)the Open Project of CAS Key Laboratory of Tropical Marine Bioresources and Ecology(No.LMB20211005).
文摘A new oxygenated tricyclic cyclopiazonic acid(CPA)alkaloid,asperorydine Q(1),along with seven known compounds,namely,asperorydines O(2)and J(3),speradine H(4),cyclopiamides A(5)and H(6),saadamysin(7),and pyrazinemethanol(8),were isolated from the coral-associated Aspergillus flavus GXIMD 02503.The structures were elucidated by physicochemical properties and comprehensive spectroscopic data analysis.Compounds 1−5 and 7−8 exhibited potent inhibition of lipopolysaccharide(LPS)-induced nuclear factor-κB(NF-κB)with the IC50 values ranging from 6.5 to 21.8μmol L^(−1).In addition,the most potent one,pyrazinemethanol(8),dose-dependently suppressed receptor activator of NF-κB ligand(RANKL)-induced osteoclast differentiation without obvious cytotoxicity in bone marrow macrophages cells(BMMCs),suggesting it is a promising lead compound for the treatment of osteolytic diseases.
基金supported by the National Key Research and Development Program of China(2019YFA0111900,2022YFC3601900 and 2022YFC2505500)the National Natural Science Foundation of China(82261160397,82272560,81922017,92149306 and 82120108009)+5 种基金the NSFC/RGC Joint Research Schemethe Research Grants Council(UGC)of the Hong Kong Special Administrative Region and the National Natural Science Foundation of China(N_CUHK483/22)the Center for Neuromusculoskeletal Restorative Medicine by Innovation and Technology Commission(ITC)of Hong Kong SAR,China(CNRM at Inno HK),the National Institutes of Health(R61-AR073518 and R01-AR071930)the Key Research and Development Program of Hunan Province(2022SK2023)the Science and Technology Innovation Program of Hunan Province(2023RC1027,2022RC1009 and 2022RC3075)the Hunan Provincial Science and Technology Department(2023JJ30896)。
文摘Mechanical loading is required for bone homeostasis,but the underlying mechanism is still unclear.Our previous studies revealed that the mechanical protein polycystin-1(PC1,encoded by Pkd1)is critical for bone formation.However,the role of PC1 in bone resorption is unknown.Here,we found that PC1directly regulates osteoclastogenesis and bone resorption.The conditional deletion of Pkd1 in the osteoclast lineage resulted in a reduced number of osteoclasts,decreased bone resorption,and increased bone mass.A cohort study of 32,500 patients further revealed that autosomal dominant polycystic kidney disease,which is mainly caused by loss-of-function mutation of the PKD1 gene,is associated with a lower risk of hip fracture than those with other chronic kidney diseases.Moreover,mice with osteoclastspecific knockout of Pkd1 showed complete resistance to unloading-induced bone loss.A mechanistic study revealed that PC1 facilitated TAZ nuclear translocation via the C-terminal tail-TAZ complex and that conditional deletion of Taz in the osteoclast lineage resulted in reduced osteoclastogenesis and increased bone mass.Pharmacological regulation of the PC1-TAZ axis alleviated unloading-and estrogen deficiency-induced bone loss.Thus,the PC1-TAZ axis may be a potential therapeutic target for osteoclast-related osteoporosis.
基金Basic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Number:2019A1515110723Key Laboratory of Guangdong Higher Education Institutes,Grant/Award Number:2021KSYS009。
文摘Background:Overproduction and activation of osteoclasts result in various bone diseases,such as osteoporosis,Paget's disease,and rheumatoid arthritis.Thus,inhibiting osteoclast formation and overactivation may effectively prevent osteoclast-related bone diseases,especially osteoporosis.Madecassic acid,one of the most important active ingredients in Centella asiatica,has various biological effects,but its role in osteoclastogenesis remains unknown.Methods:RAW 264.7 cells were stimulated with receptor activator of nuclear factor(NF)-κΒligand(RANKL,25 ng/mL)to differentiate into multinucleated osteoclasts.Subsequently,osteoclasts were treated with or without varying concentrations of madecassic acid(1,2.5,5,and 10μmol/L).Results:Madecassic acid significantly inhibited RANKL-induced osteoclastogenesis in a concentration-dependent manner.In addition,it reduced the percentage of bone resorptive area compared with the control,confirming that madecassic acid can inhibit osteoclast function.Furthermore,luciferase reporter gene studies indicate that madecassic acid could decrease the transcriptional activity of NF of activated T cells(NFAT)and NF-κB in a dose-dependent manner.Quantitative real-time polymerase chain reaction results show that madecassic acid attenuated the expression of osteoclast-associated genes,including V-ATPase-d2,cathepsin K,tartrate-resistant acid phosphatase(TRAP),NFAT cytoplasmic 1(NFATc1).Western blot analysis shows that madecassic acid inhibited RANKL-mediated degradation of IκBαand NFATc1 expression,as well as phosphorylation of c-Jun N-terminal kinase(JNK)in RAW 264.7 cells.Conclusion:Madecassic acid inhibited osteoclast formation and function in vitro by suppressing NF-κB,JNK,and NFAT signaling pathways,indicating its potential as a novel drug for the treatment of osteoclast-related bone diseases,especially osteoporosis.
基金supported by the National Natural Science Foundation of China (81550023)
文摘Rapid progress has been made in exploring the connections between the skeletal system and the immune system over the past decade. Bone tissue forms developmental niches for hematopoietic stem cells, and activated immune cells are involved in bone metabolism regulation and are potent mediators of osteoporosis and bone erosion under pathological conditions. The interdisciplinary field of osteoimmunology has emerged to pool the knowledge of the interdependence of these two systems, including the shared ligands and receptors, their crosstalk and interaction, and common intracellular signaling pathways with bidirectional influence. The receptor activator of nuclear factor-kappa B(RANK)/RANK ligand(RANKL)/osteoprotegerin(OPG) triad is the key vinculum, with multifaceted potency, being not only essential for osteoclastogenesis but also critical for lymph node organogenesis and lymphopoiesis as well as for immune regulation. In this review, we summarize the progress in this area, focusing on those aspects of interest concerning rheumatic diseases.
基金supported by National Science Centre,Poland(2013/09/N/ST8/00309)Norwegian Research Council(228415)BMBF,Germany(GoBone German-Polish bilateral project 01DS16010A).
文摘Bone tissue regeneration in critical-size defects is possible after implantation of a 3D scaffold and can be additionally enhanced once the scaffold is enriched with drugs or other factors supporting bone remodelling and healing.Sodium alendronate(Aln),a widely used anti-osteoporosis drug,exhibits strong inhibitory effect on bone resorption performed by osteoclasts.Thus,we propose a new approach for the treatment of bone defects in craniofacial region combining biocompatible titanium dioxide scaffolds and poly(L-lactide-co-glycolide)microparticles(MPs)loaded with Aln.The MPs were effectively attached to the surface of the scaffolds’pore walls by human recombinant collagen.Drug release from the scaffolds was characterized by initial burst(2466% of the drug released within first 24 h)followed by a sustained release phase(on average 5 mg of Aln released per day from Day 3 to Day 18).In vitro tests evidenced that Aln at concentrations of 5 and 2.5 mg/ml was not cytotoxic for MG-63 osteoblast-like cells(viability between 8166% and 9863% of control),but it prevented RANKL-induced formation of osteoclast-like cells from macrophages derived from peripheral blood mononuclear cells,as shown by reduced fusion capability and decreased tartrateresistant acid phosphatase 5b activity(5665% reduction in comparison to control after 8 days of culture).Results show that it is feasible to design the scaffolds providing required doses of Aln inhibiting osteoclastogenesis,reducing osteoclast activity,but not affecting osteoblast functions,which may be beneficial in the treatment of critical-size bone tissue defects.
基金financially supported by grants from the National Natural Science Foundation of China(81700938,81670957)。
文摘Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement.Compression stress also stimulates angiogenesis,which is essential for osteoclastogenesis.However,the effects of osteoclastogenesis induced by compression on angiogenesis are poorly understood.In vivo,we found the markers of angiogenesis increased during orthodontic bone remodeling.In vitro,osteoclast-derived exosomes increased proliferation,migration,and tube formation of human umbilical vein endothelial cells(HUVECs),as well as expression of vascular endothelial growth factor and CD31.The promotive effects of exosomes derived from compressed osteoclasts were greater than those derived from osteoclasts without compression.Next,we analyzed changes in the micro RNA transcriptome after compression stress and focused on micro RNA146 a-5 p(mi R-146 a),which was significantly decreased by compression.Transfection of an inhibitor of mi R-146 a stimulated angiogenesis of HUVECs while mi R-146 a mimics repressed angiogenesis.Adiponectin(ADP)was confirmed to be a target of mi R-146 a by dual luciferase reporter assay.In HUVECs treated with exosomes,we detected increased ADP which promoted angiogenesis.Knockdown of ADP in HUVECs reduced the promotive effects of exosomes.Our results demonstrate that the decreased mi R-146 a observed in osteoclasts after compression promotes angiogenesis by targeting ADP,suggesting a novel method to interfere with bone remodeling induced by compression stress.
基金supported by Natural Science Foundation of Guangdong Province of China(No.2019A1515010365)National Natural Science Foundation of China(Grant Nos U1501245 and 51672088)+1 种基金China Postdoctoral Science Foundation(2018M633065)Scientific Research Cultivation Fund for Young Teachers of South China Normal University(18KJ16).
文摘Strontium-substituted bioactive glass(Sr-BG)has shown superior performance in bone regeneration.Sr-BG-induced osteogenesis has been extensively studied;however,Sr-BG-mediated osteoclastogenesis and the underlying molecular mechanism remain unclear.It is recognized that the balance of osteogenesis and osteoclastogenesis is closely related to bone repair,and the receptor activators of nuclear factor kappaB ligand(RANKL)signaling pathway plays a key role of in the regulation of osteoclastogenesis.Herein,we studied the potential impact and underling mechanism of strontium-substituted sub-micron bioactive glass(Sr-SBG)on RANKL-induced osteoclast activation and differentiation in vitro.As expected,Sr-SBG inhibited RANKL-mediated osteoclastogenesis significantly with the experimental performance of decreased mature osteoclasts formation and downregulation of osteoclastogenesis-related gene expression.Furthermore,it was found that Sr-SBG might suppress osteoclastogenesis by the combined effect of strontium and silicon released through inhibition of RANKL-induced activation of p38 and NF-κB pathway.These results elaborated the effect of Sr-SBG-based materials on osteoclastogenesis through RANKLinduced downstream pathway and might represent a significant guidance for designing better bone repair materials.