This study investigated the regulatory potential of salidroside(SAL),a primary active compound in Rhodiola rosea L.,on osteoclast differentiation by modulating the hypoxia-inducible factor 1-alpha(HIF-1α)pathway in o...This study investigated the regulatory potential of salidroside(SAL),a primary active compound in Rhodiola rosea L.,on osteoclast differentiation by modulating the hypoxia-inducible factor 1-alpha(HIF-1α)pathway in osteoblasts.Luciferase reporter assay and chromatin immunoprecipitation(Ch IP)assay were employed to validate whether the receptor activator of nuclear factor-κB ligand(RANKL)is the downstream target gene of HIF-1αin osteoblasts.The study also utilized lipopolysaccharide(LPS)-induced mouse osteolysis to examine the impact of SAL on osteolysis in vivo.Furthermore,conditioned medium(CM)from SAL-pretreated osteoblasts was used to investigate the paracrine effects on osteoclastogenesis through the HIF-1αpathway.Hypoxic condition-induced overexpression of HIF-1αupregulated RANKL levels by binding to the RANKL promoter and enhancing transcription in osteoblastic cells.In vivo,SAL significantly alleviated bone tissue hypoxia and decreased the expression of HIF-1αby downregulating the expression of RANKL,vascular endothelial growth factor(VEGF),interleukin 6(IL-6),and angiopoietin-like 4(ANGPTL4).In the paracrine experiment,conditioned media from SAL-pretreated osteoblasts inhibited differentiation through the HIF-1α/RANKL,VEGF,IL-6,and ANGPTL4 pathways.RANKL emerges as the downstream target gene regulated by HIF-1αin osteoblasts.SAL significantly alleviates bone tissue hypoxia and bone loss in LPS-induced osteolysis through the HIF-1α/RANKL,VEGF,IL-6,and ANGPTL4 pathways.SAL inhibits osteoclast differentiation by regulating osteoblast paracrine secretion.展开更多
Osteoporosis is a prevalent skeletal condition characterized by reduced bone mass and strength,leading to increased fragility.Buqi-Tongluo(BQTL)decoction,a traditional Chinese medicine(TCM)prescription,has yet to be f...Osteoporosis is a prevalent skeletal condition characterized by reduced bone mass and strength,leading to increased fragility.Buqi-Tongluo(BQTL)decoction,a traditional Chinese medicine(TCM)prescription,has yet to be fully evaluated for its potential in treating bone diseases such as osteoporosis.To investigate the mechanism by which BQTL decoction inhibits osteoclast differentiation in vitro and validate these findings through in vivo experiments.We employed MTS assays to assess the potential proliferative or toxic effects of BQTL on bone marrow macrophages(BMMs)at various concentrations.TRAc P experiments were conducted to examine BQTL's impact on osteoclast differentiation.RT-PCR and Western blot analyses were utilized to evaluate the relative expression levels of osteoclast-specific genes and proteins under BQTL stimulation.Finally,in vivo experiments were performed using an osteoporosis model to further validate the in vitro findings.This study revealed that BQTL suppressed receptor activator of NF-κB ligand(RANKL)-induced osteoclastogenesis and osteoclast resorption activity in vitro in a dose-dependent manner without observable cytotoxicity.The inhibitory effects of BQTL on osteoclast formation and function were attributed to the downregulation of NFATc1 and c-fos activity,primarily through attenuation of the MAPK,NF-κB,and Calcineurin signaling pathways.BQTL's inhibitory capacity was further examined in vivo using an ovariectomized(OVX)rat model,demonstrating a strong protective effect against bone loss.BQTL may serve as an effective therapeutic TCM for the treatment of postmenopausal osteoporosis and the alleviation of bone loss induced by estrogen deficiency and related conditions.展开更多
Rheumatoid arthritis(RA)is an autoimmune disease characterized by inflammation and abnormal osteoclast activation,leading to bone destruction.We previously demonstrated that the large extracellular loop(LEL)of Tm4sf19...Rheumatoid arthritis(RA)is an autoimmune disease characterized by inflammation and abnormal osteoclast activation,leading to bone destruction.We previously demonstrated that the large extracellular loop(LEL)of Tm4sf19 is important for its function in osteoclast differentiation,and LEL-Fc,a competitive inhibitor of Tm4sf19,effectively suppresses osteoclast multinucleation and prevent bone loss associated with osteoporosis.This study aimed to investigate the role of Tm4sf19 in RA,an inflammatory and abnormal osteoclast disease,using a mouse model of collagen-induced arthritis(CIA).Tm4sf19 expression was observed in macrophages and osteoclasts within the inflamed synovium,and Tm4sf19 expression was increased together with inflammatory genes in the joint bones of CIA-induced mice compared with the sham control group.Inhibition of Tm4sf19 by LEL-Fc demonstrated both preventive and therapeutic effects in a CIA mouse model,reducing the CIA score,swelling,inflammation,cartilage damage,and bone damage.Knockout of Tm4sf19 gene or inhibition of Tm4sf19 activity by LEL-Fc suppressed LPS/IFN-γ-induced TLR4-mediated inflammatory signaling in macrophages.LEL-Fc disrupted not only the interaction between Tm4sf19 and TLR4/MD2,but also the interaction between TLR4 and MD2.μCT analysis showed that LEL-Fc treatment significantly reduced joint bone destruction and bone loss caused by hyperactivated osteoclasts in CIA mice.Taken together,these findings suggest that LELFc may be a potential treatment for RA and RA-induced osteoporosis by simultaneously targeting joint inflammation and bone destruction caused by abnormal osteoclast activation.展开更多
Polyetheretherketone(PEEK)is a desirable candidate to replace conventional metal implants owing to its excellent mechanical properties.However,the intrinsic bioinertness of PEEK results in inferior or delayed osseoint...Polyetheretherketone(PEEK)is a desirable candidate to replace conventional metal implants owing to its excellent mechanical properties.However,the intrinsic bioinertness of PEEK results in inferior or delayed osseointegration,which limits its further clinical application.To address these challenges,one leading strategy is to construct a biofunctionalized surface on PEEK that provides a coordinated osteoblastosteoclast interactions microenvironment.Herein,alendronate(ALN),a common bone absorption inhibitor,was loaded in biomedical inorganic/organic microspheres,consisting of bioactive inorganic nanohydroxyapatite core,and chitosan(CS)shell.Polydopamine(PDA)modification was employed to ensure the adherence of the microspheres to the PEEK surface.The delivery of ALN and Ca^(2+)from these microspheres simultaneously suppressed osteoclastogenesis and promoted osteogenesis,resulting in a coordinated cascade of osteoblast-osteoclast interactions crucial for the per-implant osseointegration.In vitro experiments demonstrated that the PEEK surface exhibited satisfactory biocompatibility and enhanced the proliferation and osteogenic differentiation of rat bone mesenchymal stem cells while inhibiting the osteoclast differentiation.Moreover,the in vivo rat femoral drilling model demonstrated superior osseointegration three months after implantation.By considering the bone remodeling processes,this study proposes a novel biofunctionalized PEEK surface that regulates the activities of both osteoblasts and osteoclasts to promote osseointegration.展开更多
Abnormal activation of macrophages and osteoclasts(OCs)contributes significantly to rheumatoid arthritis(RA)development by secretion of numerous inflammatory factors.Notably,these cells exhibit significant upregulatio...Abnormal activation of macrophages and osteoclasts(OCs)contributes significantly to rheumatoid arthritis(RA)development by secretion of numerous inflammatory factors.Notably,these cells exhibit significant upregulation of folate receptor proteins on their surfaces.Unfortunately,there is a current lack of safe and effective therapeutic drugs for RA.Xuetongsu(XTS),a triterpenoid compound extracted fromKadsura heteroclita Roxb Craib,has demonstrated the ability to significantly inhibit the proliferation of RA fibroblast-like synoviocytes(RAFLS).However,its clinical application is hampered by poor targeting and short half-life.To address these drawbacks,we previously developed a nano-drug system named HRPS nanoparticles(NPs),which effectively targets RAFLS and inhibits synovial hyperplasia.However,this system overlooked the essential role of OCs in RA-related bone destruction.Therefore,we designed a novel folate-modified biomimetic Prussian blue(PB)-XTS NP(FMPX NP)for the selective delivery of XTS into inflammatory macrophages and OCs.The NP exhibits an excellent photothermal effect when assisted by laser irradiation,facilitating targeted release of XTS within inflammatory macrophages and OCs.The synergistic anti-inflammatory and reactive oxygen species scavenging effects of PB NPs and XTS are mediated by the inhibition of the NF-κB signaling pathway in inflammatory macrophages and RANK/RANKL/NFATc1 signaling pathway in OCs.In vivo experiments showed that FMPX NPs extended the half-life of XTS by 2.32 times,decreased hind foot swelling from 12.10±0.49 mm to 8.24±0.09 mm in the model group,and prevented bone damage.In conclusion,this study introduces a novel dual-targeted nano-based therapy for RA joints and highlights its potential for biochemical photothermal triple therapy for RA.FMPX NPs inhibit arthritis-related inflammation and bone destruction through a dual-target strategy,providing new insights for targeted drug therapies in clinical RA treatment.展开更多
BACKGROUND This study analyzed the dental follicle and alveolar bone of two patients with tooth eruption disorders,aiming to provide some reference for exploring the etiology and selecting treatment plans of this dise...BACKGROUND This study analyzed the dental follicle and alveolar bone of two patients with tooth eruption disorders,aiming to provide some reference for exploring the etiology and selecting treatment plans of this disease from the perspective of the influence of extracellular matrix on osteoclasts differentiation in dental follicle.CASE SUMMARY Collect dental follicle and alveolar bone tissue from one patient with single tooth eruption disorder and one patient with full permanent tooth eruption disorder,respectively.Simultaneously collect the dental follicle and alveolar bone tissue of obstructed teeth that need to be extracted due to orthodontic treatment as the control group.Hematoxylin and eosin(HE)staining was used to observe the morphology of dental follicle cells.Immunohistochemical staining was used to observe the expression of periostin,receptor activator of nuclear factor kappa B ligand(RANKL),and osteoprotegerin(OPG)protein in dental follicle and alveolar bone tissue.And observe the eruption of teeth after removing resistance from the crown of the permanent tooth germ.CONCLUSION HE staining of two cases of dental follicle tissues showed that the volume of dental follicle cells decreased,the nuclei were condensed,and there seemed to be cellular fibrosis.The immunohistochemical staining showed that both the dental follicle and alveolar bone tissue exhibited increased expression of periostin,decreased expression of RANKL and OPG proteins,and decreased RANKL/OPG ratio.After removing resistance,the permanent tooth germ often appears to have normal eruption.Tooth eruption disorders may be accompanied by abnormal remodeling of periostin,which affects the differentiation function of osteoclasts in the dental follicle and leads to metabolic imbalance of alveolar bone,resulting in tooth eruption disorders.Whether it is a single or full permanent tooth eruption disorder,once the coronal resistance is removed,the teeth can often erupt normally.展开更多
Itaconate,a macrophage-specific anti-inflammatory metabolite,has recently emerged as a critical regulator in rheumatoid arthritis pathogenesis.We found that itaconate is a TNF-αresponsive metabolite significantly ele...Itaconate,a macrophage-specific anti-inflammatory metabolite,has recently emerged as a critical regulator in rheumatoid arthritis pathogenesis.We found that itaconate is a TNF-αresponsive metabolite significantly elevated in the serum and synovial fluid of rheumatoid arthritis patients and we demonstrated that itaconate is primarily produced by inflammatory macrophages rather than osteoclasts or osteoblasts.In TNF-transgenic and Irg1−/−hybrid mice,a more severe bone destruction phenotype was observed.展开更多
Complement C3 plays a critical role in periodontitis.However,its source,role and underlying mechanisms remain unclear.In our study,by analyzing single-cell sequencing data from mouse model of periodontitis,we identifi...Complement C3 plays a critical role in periodontitis.However,its source,role and underlying mechanisms remain unclear.In our study,by analyzing single-cell sequencing data from mouse model of periodontitis,we identified that C3 is primarily derived from periodontal fibroblasts.Subsequently,we demonstrated that C3a has a detrimental effect in ligature-induced periodontitis.C3ar−/−mice exhibited significantly less destruction of periodontal support tissues compared to wild-type mice,characterized by mild gingival tissue damage and reduced alveolar bone loss.This reduction was associated with decreased production of proinflammatory mediators and reduced osteoclast infiltration in the periodontal tissues.Mechanistic studies suggested that C3a could promote macrophage polarization and osteoclast differentiation.Finally,by analyzing single-cell sequencing data from the periodontal tissues of patients with periodontitis,we found that the results observed in mice were consistent with human data.Therefore,our findings clearly demonstrate the destructive role of fibroblast-derived C3 in ligature-induced periodontitis,driven by macrophage M1 polarization and osteoclast differentiation.These data strongly support the feasibility of C3a-targeted interventions for the treatment of human periodontitis.展开更多
BACKGROUND In vivo degradation of bone scaffolds is significantly influenced by osteoclast(OC)activity,which is orchestrated by the interplay between receptor activator of nuclear factor-kappa B ligand(RANKL)and osteo...BACKGROUND In vivo degradation of bone scaffolds is significantly influenced by osteoclast(OC)activity,which is orchestrated by the interplay between receptor activator of nuclear factor-kappa B ligand(RANKL)and osteoprotegerin(OPG).The ratio of RANKL/OPG is a crucial determinant of OC-mediated bone resorption,which plays an integral role in bone remodeling and scaffold degradation.Elevated levels of RANKL relative to OPG enhance osteoclastogenesis,thereby accelerating the degradation process essential for integrating bone scaffolds into the host tissue.AIM To elucidate the effects of OPG gene silencing on osteoclastogenesis within rat bone marrow-derived mesenchymal stem cells(BMSCs).By investigating these effects,the study aimed to provide deeper insights into the regulatory mechanisms that influence bone scaffold degradation,potentially leading to improved bone repair and regeneration strategies.METHODS We employed recombinant lentiviral plasmids to silence the OPG gene in rat BMSCs to achieve the aims.The efficacy of gene silencing was assessed using quantitative reverse transcription polymerase chain reaction and western blot analysis to measure the expression levels of OPG and RANKL.Tartrate-resistant acid phosphatase staining was utilized to evaluate the formation of OCs.Additionally,co-immunoprecipitation assays were conducted to explore the interactions between RANKL and OPG proteins,further assessing the biochemical pathways involved in osteoclastogenesis.RESULTS The silencing of the OPG gene in BMSCs resulted in a significant increase in the RANKL/OPG ratio,evidenced by decreased expression levels of OPG and increased levels of RANKL.Enhanced osteoclastogenesis was observed through tartrate-resistant acid phosphatase staining,which indicated a substantial rise in OC formation in response to the altered RANKL/OPG balance.The co-immunoprecipitation assays provided concrete evidence of the direct interaction between RANKL and OPG proteins,substantiating their pivotal roles in regulating OC activity.CONCLUSION The findings from this study underscore the critical role of the RANKL/OPG axis in osteoclastogenesis.Silencing of the OPG gene in BMSCs effectively increases the RANKL/OPG ratio,promoting OC activity and potentially enhancing bone scaffold degradation.This regulatory mechanism offers a promising avenue for modulating bone remodeling processes,which is essential for effective bone repair and the successful integration of bone scaffolds into damaged sites.Future research might focus on optimizing the control of this axis to better facilitate bone tissue engineering and regenerative therapies.展开更多
Osteogenesis imperfecta(OI)is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility.While these disorders have been regarded as defects in osteoblast function,the role ...Osteogenesis imperfecta(OI)is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility.While these disorders have been regarded as defects in osteoblast function,the role of matrix-embedded osteocytes in OI pathogenesis remains largely unknown.Homozygous human SP7(c.946 C>T,R316C)mutation results in a recessive form of OI characterized by fragility fractures,low bone mineral density and osteocyte dendrite defects.To better understand how the OI-causing R316C mutation affects the function of SP7,we generated Sp7^(R342C)knock-in mice.Consistent with patient phenotypes,Sp7^(R342C/R342C)mice demonstrate increased cortical porosity and reduced cortical bone mineral density.Sp7^(R342C/R342C)mice show osteocyte dendrite defects,increased osteocyte apoptosis,and intracortical bone remodeling with ectopic intracortical osteoclasts and elevated osteocyte Tnfsf11 expression.展开更多
Objective: To purify and identify the osteoclasts from the tissue of humangiant cell tumor of bone. Methods: We have developed a new method that allows the purification oflarge numbers of authentic osteoclasts (OCs). ...Objective: To purify and identify the osteoclasts from the tissue of humangiant cell tumor of bone. Methods: We have developed a new method that allows the purification oflarge numbers of authentic osteoclasts (OCs). The OCs were isolated from tissue of human giant celltumor of bone by 0.25% trypsin and collagenase. We characterized OCs in terms of the expression ofdifferent phenotypic markers of OCs. The phenotypic markers of OC included Tartrate-resistant acidphosphatase staining (TRAP). The expression of calcitonin receptor (CTR), cathepsin K and receptoractivator of necrosis factor κB (RANK) mRNA were examined by RT-PCR. Results: The OC cell purifiedby above method functioned normally in vitro. The purity was about 79.7%. They showed the normalosteoclast phenotypes markers of OC. Conclusion: The method provides a system for performingbiochemical and molecular studies of OCs. The study indicates that the method of purifying theosteoclasts from human GCT cell can be used for research of bone metabolism.展开更多
The skeleton is a dynamic organ that is constantly remodeled. Proteins secreted from bone cells, namely osteoblasts, osteocytes,and osteoclasts exert regulation on osteoblastogenesis, osteclastogenesis, and angiogenes...The skeleton is a dynamic organ that is constantly remodeled. Proteins secreted from bone cells, namely osteoblasts, osteocytes,and osteoclasts exert regulation on osteoblastogenesis, osteclastogenesis, and angiogenesis in a paracrine manner. Osteoblasts secrete a range of different molecules including RANKL/OPG, M-CSF, SEMA3A, WNT5A, and WNT16 that regulate osteoclastogenesis. Osteoblasts also produce VEGFA that stimulates osteoblastogenesis and angiogenesis. Osteocytes produce sclerostin（SOST） that inhibits osteoblast differentiation and promotes osteoclast differentiation. Osteoclasts secrete factors including BMP6, CTHRC1, EFNB2, S1P, WNT10B, SEMA4D, and CT-1 that act on osteoblasts and osteocytes, and thereby influencea A osteogenesis. Osteoclast precursors produce the angiogenic factor PDGF-BB to promote the formation of Type H vessels, which then stimulate osteoblastogenesis. Besides, the evidences over the past decades show that at least three hormones or ＂osteokines＂from bone cells have endocrine functions. FGF23 is produced by osteoblasts and osteocytes and can regulate phosphate metabolism. Osteocalcin（OCN） secreted by osteoblasts regulates systemic glucose and energy metabolism, reproduction, and cognition. Lipocalin-2（LCN2） is secreted by osteoblasts and can influence energy metabolism by suppressing appetite in the brain.We review the recent progresses in the paracrine and endocrine functions of the secretory proteins of osteoblasts, osteocytes, and osteoclasts, revealing connections of the skeleton with other tissues and providing added insights into the pathogenesis of degenerative diseases affecting multiple organs and the drug discovery process.展开更多
The present study aimed at investigating the effects of Puerarin(PR), a major isoflavonoid isolated from the Chinese medicinal herb Puerariae radix, on bone metabolism and the underlying mechanism of action. The in vi...The present study aimed at investigating the effects of Puerarin(PR), a major isoflavonoid isolated from the Chinese medicinal herb Puerariae radix, on bone metabolism and the underlying mechanism of action. The in vivo assay, female mice were ovariectomized(OVX), and the OVX mice were fed with a diet containing low, middle, and high doses of PR(2, 4, and 8 mg·d^(-1), respectively) or 17β-estradiol(E_2, 0.03 μg·d^(-1)) for 4 weeks. In OVX mice, the uterine weight declined, and intake of PR at any dose did not affect uterine weight, compared with the control. The total femoral bone mineral density(BMD) was significantly reduced by OVX, which was reversed by intake of the diet with PR at any dose, especially at the low dose. In the in vitro assay, RAW264.7 cells were used for studying the direct effect of PR on the formation of osteoclasts. PR reduced the formation of tartrate resistant acid phosphatase(TRAP)-positive multi-nucleated cells in the RAW 264.7 cells induced by receptor activator for nuclear factor-κB Ligand(RANKL). MC3T3-E1 cells were used for studying the effects of PR on the expression of osteoprotegerin(OPG) and RANKL m RNA expression in osteoblasts. The expression of OPG m RNA and RANKL m RNA was detected by RT-PCR on Days of 5, 7, 10, and 12 after PR exposure. PR time-dependently enhanced the expression of OPG m RNA and reduced the expression of RANKL m RNA in MC3T3-E1 cells. In conclusion, our results suggest that PR can effectively prevent bone loss in OVX mice without any hyperplastic effect on the uterus, and the antiosteoporosis activity of PR may be related to its effects on the formation of osteoclasts and the expression of RANKL OPG in osteoblasts.展开更多
Osteoclasts, the bone-resorbing cells, play a pivotal role in skeletal development and adult bone remodeling. They also participate in the pathogenesis of various bone disorders. Osteoclasts differentiate from cells o...Osteoclasts, the bone-resorbing cells, play a pivotal role in skeletal development and adult bone remodeling. They also participate in the pathogenesis of various bone disorders. Osteoclasts differentiate from cells of the monocyte/macrophage lineage upon stimulation of two essential factors, the monocyte/ macrophage colony stimulating factor （M-CSF） and receptor activation of NF-κB ligand （RANKL）. M-CSF binds to its receptor c-Fms to activate distinct signaling pathways to stimulate the proliferation and survival of osteoclast precursors and the mature cell. RANKL, however, is the primary osteoclast differentiation factor, and promotes osteoclast differentiation mainly through controlling gene expression by activating its receptor, RANK. Osteoclast function depends on polarization of the cell, induced by integrin avβ3, to form the resorptive machinery characterized by the attachment to the bone matrix and the formation of the bone-apposed ruffled border. Recent studies have provided new insights into the mechanism of osteoclast differentiation and bone resorption. In particular, c-Fms and RANK signaling have been shown to regulate bone resorption by cross-talking with those activated by integrin avβ3. This review discusses new advances in the understanding of the mechanisms of osteoclast differentiation and function.展开更多
Osteoclasts are the bone resorbing cells essential for bone remodeling.Osteoclasts are formed from hematopoietic progenitors in the monocyte/macrophage lineage.Osteoclastogenesis is composed of several steps including...Osteoclasts are the bone resorbing cells essential for bone remodeling.Osteoclasts are formed from hematopoietic progenitors in the monocyte/macrophage lineage.Osteoclastogenesis is composed of several steps including progenitor survival,differentiation to mononuclear pre-osteoclasts,fusion to multi-nuclear mature osteoclasts,and activation to bone resorbing osteoclasts.The regulation of osteoclastogenesis has been extensively studied,in which the receptor activator of NF-κB ligand(RANKL)-mediated signaling pathway and downstream transcription factors play essential roles.However,less is known about osteoclast fusion,which is a property of mature osteoclasts and is required for osteoclasts to resorb bone.Several proteins that affect cell fusion have been identified.Among them,dritic cell-specific transmembrane protein(DC-STAMP)is directly associated to osteoclast fusion in vivo.Cytokines and factors influence osteoclast fusion through regula-tion of DC-STAMP.Here we review the recently discovered new factors that regulate osteoclast fusion with specific focus on DC-STAMP.A better understanding of the mechanistic basis of osteoclast fusion will lead to the development of a new therapeutic strategy for bone disorders due to elevated osteoclast bone resorption.Cell-cell fusion is essential for a variety of cellular biological processes.In mammals,there is a limited number of cell types that fuse to form multinucleated cells,such as the fusion of myoblasts for the formation of skeletal muscle and the fusion of cells of the monocyte/macrophage lineage for the formation of multinucleated osteoclasts and giant cells.In most cases,cellcell fusion is beneficial for cells by enhancing function.Myoblast fusion increases myofiber size and diameter and thereby increases contractile strength.Multinucleated osteoclasts have far more bone resorbing activity than their mono-nuclear counterparts.Multinucleated giant cells are much more efficient in the removal of implanted materials and bacteria due to chronic infection than macrophages.Therefore,they are also called foreign-body giant cells.Cell fusion is a complicated process involving cell migration,chemotaxis,cell-cell recognition and attachment,as well as changes into a fusion-competent status.All of these steps are regulated by multiple factors.In this review,we will discuss osteoclast fusion and regulation.展开更多
Bone-resorbing osteoclasts are formed from a monocyte/macrophage lineage under the strict control o bone-forming osteoblasts. So far,macrophage colonystimulating factor(M-CSF),receptor activator o nuclear factor-κB l...Bone-resorbing osteoclasts are formed from a monocyte/macrophage lineage under the strict control o bone-forming osteoblasts. So far,macrophage colonystimulating factor(M-CSF),receptor activator o nuclear factor-κB ligand(RANKL),and osteoprotegerin(OPG) produced by osteoblasts play major roles in the regulation of osteoclast differentiation. Recent studies have shown that osteoblasts regulate osteoclastogenesis through several mechanisms independent o M-CSF,RANKL,and OPG production. Identification o osteoclast-committed precursors in vivo demonstrated that osteoblasts are involved in the distribution o osteoclast precursors in bone. Interleukin 34(IL-34)a novel ligand for c-Fms,plays a pivotal role in maintaining the splenic reservoir of osteoclast-committed precursors in M-CSF deficient mice. IL-34 is also able to act as a substitute for osteoblast-producing M-CSF in osteoclastogenesis. Wnt5 a,produced by osteoblasts,enhances osteoclast differentiation by upregulating RANK expression through activation of the noncanonical Wnt pathway. Semaphorin 3A produced by osteoblasts inhibits RANKL-induced osteoclast differentiation through the suppression of immunoreceptortyrosine-based activation motif signals. Thus,recent findings show that osteoclast differentiation is tightly regulated by osteoblasts through several different mechanisms. These newly identified molecules are expected to be promising targets of therapeutic agents in bone-related diseases.展开更多
In this study,the CoCrW-x Cu alloys(x=2,3 and 4 wt%)were fabricated using selective laser melting(abbreviated as Co-2 Cu,Co-3 Cu and Co-4Cu)with the purpose of reducing the inflammation responses and the activity of o...In this study,the CoCrW-x Cu alloys(x=2,3 and 4 wt%)were fabricated using selective laser melting(abbreviated as Co-2 Cu,Co-3 Cu and Co-4Cu)with the purpose of reducing the inflammation responses and the activity of osteoclast.The metal ions releasing test showed that when the Cu content was less than 4 wt%,the releasing amount of Co and Cr ions was very small;however,when 4 wt%Cu was added in the CoCrW based alloy,the quantity of Co ions was significantly elevated with respect to the other groups due to the segregation of precipitates in the matrix;the Cu2+ion quantity of the Co-2Cu,Co-3Cu and Co-4Cu alloys were 0.05,0.09 and 0.27 g/(L cm2)after 7 d immersion,respectively;the RT-q PCR and ELISA data indicated that the expression levels of the pro-inflammatory cytokines(TNF-αand IL-6)were down-regulated in the Co-3Cu and Co-4Cu groups,whereas the expression level of the anti-inflammatory cytokine(IL-10)was up-regulated in all CoCrW-x Cu alloys;meanwhile,the Cu-containing CoCrW alloys significantly down-regulated the expression of the NF-B signal pathway in a Cu content-dependent manner,and the downstream transcription factors of NF-B signal pathway including NFATc1,TRAP and Cath-K were also down-regulated via potentially manipulating the NF-B signal pathway.After comprehensive consideration,it is considered that the Co-3Cu alloy is a potential material for self-alleviating inflammatory responses.展开更多
Prostaglandin E2(PGE2), a major cyclooxygenase-2(COX-2) product, is highly secreted by the osteoblast lineage in the subchondral bone tissue of osteoarthritis(OA) patients. However, NSAIDs, including COX-2 inhibitors,...Prostaglandin E2(PGE2), a major cyclooxygenase-2(COX-2) product, is highly secreted by the osteoblast lineage in the subchondral bone tissue of osteoarthritis(OA) patients. However, NSAIDs, including COX-2 inhibitors, have severe side effects during OA treatment. Therefore, the identification of novel drug targets of PGE2 signaling in OA progression is urgently needed. Osteoclasts play a critical role in subchondral bone homeostasis and OA-related pain. However, the mechanisms by which PGE2 regulates osteoclast function and subsequently subchondral bone homeostasis are largely unknown. Here, we show that PGE2 acts via EP4 receptors on osteoclasts during the progression of OA and OA-related pain. Our data show that while PGE2 mediates migration and osteoclastogenesis via its EP2 and EP4 receptors, tissue-specific knockout of only the EP4 receptor in osteoclasts(EP4 Lys M) reduced disease progression and osteophyte formation in a murine model of OA. Furthermore, OA-related pain was alleviated in the EP4 Lys M mice, with reduced Netrin-1 secretion and CGRP-positive sensory innervation of the subchondral bone. The expression of plateletderived growth factor-BB(PDGF-BB) was also lower in the EP4 Lys Mmice, which resulted in reduced type H blood vessel formation in subchondral bone. Importantly, we identified a novel potent EP4 antagonist, HL-43, which showed in vitro and in vivo effects consistent with those observed in the EP4 Lys Mmice. Finally, we showed that the Gαs/PI3 K/AKT/MAPK signaling pathway is downstream of EP4 activation via PGE2 in osteoclasts. Together, our data demonstrate that PGE2/EP4 signaling in osteoclasts mediates angiogenesis and sensory neuron innervation in subchondral bone, promoting OA progression and pain, and that inhibition of EP4 with HL-43 has therapeutic potential in OA.展开更多
Giant cell tumors of the pancreas come in three varieties-osteoclastic,pleomorphic,and mixed histology.These tumors have distinctive endoscopic,clinical,and cytological features.Giant cell tumors have a controversial ...Giant cell tumors of the pancreas come in three varieties-osteoclastic,pleomorphic,and mixed histology.These tumors have distinctive endoscopic,clinical,and cytological features.Giant cell tumors have a controversial histogenesis,with some authors favoring an epithelial origin and others favoring a mesenchymal origin.The true origin of these lesions remains unclear at this time.These are also very rare tumors but proper identification and differentiation from more common pancreatic adenocarcinoma is important.The risk factors of these tumors and the prognosis may be different from those associated with standard pancreatic adenocarcinoma.Recognition of these differences can significantly affect patient care.These lesions have a unique appearance when imaged with endoscopic ultrasound(EUS),and these lesions can be diagnosed via EUS guided Fine Needle Aspiration(FNA).This manuscript will review the endoscopic,clinical,and pathologic features of these tumors.展开更多
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 re...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(lnc RNAs)are a newly identified class of functional RNAs that regulate cellular processes,such as gene expression and translation regulation.Recently,lnc RNAs 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 lnc RNAs in osteoclast formation and bone resorption urgently needs to be clarified.We recently found that the lnc RNA 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 c TG)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 lnc RNAs could be potential targets to regulate osteoclastogenesis and orthodontic tooth movement speed in the clinic in the future.展开更多
基金supported by grants from the National Natural Science Foundation of China(Nos.81572852 and 82104671)the Great Program of the Science Foundation of Tianjin(No.18JCZDJC33200)+1 种基金Heilongjiang Province Fund(No.LH2020H102)Tianjin Key Medical Discipline(Specialty)Construction Project(No.TJYXZDXK-032A)。
文摘This study investigated the regulatory potential of salidroside(SAL),a primary active compound in Rhodiola rosea L.,on osteoclast differentiation by modulating the hypoxia-inducible factor 1-alpha(HIF-1α)pathway in osteoblasts.Luciferase reporter assay and chromatin immunoprecipitation(Ch IP)assay were employed to validate whether the receptor activator of nuclear factor-κB ligand(RANKL)is the downstream target gene of HIF-1αin osteoblasts.The study also utilized lipopolysaccharide(LPS)-induced mouse osteolysis to examine the impact of SAL on osteolysis in vivo.Furthermore,conditioned medium(CM)from SAL-pretreated osteoblasts was used to investigate the paracrine effects on osteoclastogenesis through the HIF-1αpathway.Hypoxic condition-induced overexpression of HIF-1αupregulated RANKL levels by binding to the RANKL promoter and enhancing transcription in osteoblastic cells.In vivo,SAL significantly alleviated bone tissue hypoxia and decreased the expression of HIF-1αby downregulating the expression of RANKL,vascular endothelial growth factor(VEGF),interleukin 6(IL-6),and angiopoietin-like 4(ANGPTL4).In the paracrine experiment,conditioned media from SAL-pretreated osteoblasts inhibited differentiation through the HIF-1α/RANKL,VEGF,IL-6,and ANGPTL4 pathways.RANKL emerges as the downstream target gene regulated by HIF-1αin osteoblasts.SAL significantly alleviates bone tissue hypoxia and bone loss in LPS-induced osteolysis through the HIF-1α/RANKL,VEGF,IL-6,and ANGPTL4 pathways.SAL inhibits osteoclast differentiation by regulating osteoblast paracrine secretion.
基金supported by the Natural Science Foundation of Guangdong Province,China(No.2021A1515012168)the Administration of Traditional Chinese Medicine of Guangdong Province,China(Nos.20221146 and 20241091)+5 种基金the Basic and Applied Basic Research Fund Project in Guangdong Province,China(No.2020A1515110948)the Basic and Applied Basic Research in Jointly Funded Projects of City Schools(Institutes)Projects,China(Nos.202201020500 and 202201020295)the Project of Guangzhou Science and Technology Department,China(No.202102021040)the Guangzhou Science and Technology Plan Project,China(No.2023B03J0379)the Chinese Society of Traditional Chinese Medicine Youth Talent Lifting Project(No.2022-QNRC2-B11)the Hospital Young and Middle-aged Key Talent Cultivation Project of The First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine(2023-10)。
文摘Osteoporosis is a prevalent skeletal condition characterized by reduced bone mass and strength,leading to increased fragility.Buqi-Tongluo(BQTL)decoction,a traditional Chinese medicine(TCM)prescription,has yet to be fully evaluated for its potential in treating bone diseases such as osteoporosis.To investigate the mechanism by which BQTL decoction inhibits osteoclast differentiation in vitro and validate these findings through in vivo experiments.We employed MTS assays to assess the potential proliferative or toxic effects of BQTL on bone marrow macrophages(BMMs)at various concentrations.TRAc P experiments were conducted to examine BQTL's impact on osteoclast differentiation.RT-PCR and Western blot analyses were utilized to evaluate the relative expression levels of osteoclast-specific genes and proteins under BQTL stimulation.Finally,in vivo experiments were performed using an osteoporosis model to further validate the in vitro findings.This study revealed that BQTL suppressed receptor activator of NF-κB ligand(RANKL)-induced osteoclastogenesis and osteoclast resorption activity in vitro in a dose-dependent manner without observable cytotoxicity.The inhibitory effects of BQTL on osteoclast formation and function were attributed to the downregulation of NFATc1 and c-fos activity,primarily through attenuation of the MAPK,NF-κB,and Calcineurin signaling pathways.BQTL's inhibitory capacity was further examined in vivo using an ovariectomized(OVX)rat model,demonstrating a strong protective effect against bone loss.BQTL may serve as an effective therapeutic TCM for the treatment of postmenopausal osteoporosis and the alleviation of bone loss induced by estrogen deficiency and related conditions.
基金supported by GILO Foundation.This research is in part supported by Korea Drug Development Fund funded by Ministry of Science and ICT,Ministry of Trade,Industry,and Energy,and Ministry of Health and Welfare(RS-2023-00282595,Republic of Korea).
文摘Rheumatoid arthritis(RA)is an autoimmune disease characterized by inflammation and abnormal osteoclast activation,leading to bone destruction.We previously demonstrated that the large extracellular loop(LEL)of Tm4sf19 is important for its function in osteoclast differentiation,and LEL-Fc,a competitive inhibitor of Tm4sf19,effectively suppresses osteoclast multinucleation and prevent bone loss associated with osteoporosis.This study aimed to investigate the role of Tm4sf19 in RA,an inflammatory and abnormal osteoclast disease,using a mouse model of collagen-induced arthritis(CIA).Tm4sf19 expression was observed in macrophages and osteoclasts within the inflamed synovium,and Tm4sf19 expression was increased together with inflammatory genes in the joint bones of CIA-induced mice compared with the sham control group.Inhibition of Tm4sf19 by LEL-Fc demonstrated both preventive and therapeutic effects in a CIA mouse model,reducing the CIA score,swelling,inflammation,cartilage damage,and bone damage.Knockout of Tm4sf19 gene or inhibition of Tm4sf19 activity by LEL-Fc suppressed LPS/IFN-γ-induced TLR4-mediated inflammatory signaling in macrophages.LEL-Fc disrupted not only the interaction between Tm4sf19 and TLR4/MD2,but also the interaction between TLR4 and MD2.μCT analysis showed that LEL-Fc treatment significantly reduced joint bone destruction and bone loss caused by hyperactivated osteoclasts in CIA mice.Taken together,these findings suggest that LELFc may be a potential treatment for RA and RA-induced osteoporosis by simultaneously targeting joint inflammation and bone destruction caused by abnormal osteoclast activation.
基金the funding support from the Tianjin Medical University“Clinical Talent Training 123 Climbing Plan”the Youth Fund of Tianjin Medical University Second Hospital(No.2022ydey06)。
文摘Polyetheretherketone(PEEK)is a desirable candidate to replace conventional metal implants owing to its excellent mechanical properties.However,the intrinsic bioinertness of PEEK results in inferior or delayed osseointegration,which limits its further clinical application.To address these challenges,one leading strategy is to construct a biofunctionalized surface on PEEK that provides a coordinated osteoblastosteoclast interactions microenvironment.Herein,alendronate(ALN),a common bone absorption inhibitor,was loaded in biomedical inorganic/organic microspheres,consisting of bioactive inorganic nanohydroxyapatite core,and chitosan(CS)shell.Polydopamine(PDA)modification was employed to ensure the adherence of the microspheres to the PEEK surface.The delivery of ALN and Ca^(2+)from these microspheres simultaneously suppressed osteoclastogenesis and promoted osteogenesis,resulting in a coordinated cascade of osteoblast-osteoclast interactions crucial for the per-implant osseointegration.In vitro experiments demonstrated that the PEEK surface exhibited satisfactory biocompatibility and enhanced the proliferation and osteogenic differentiation of rat bone mesenchymal stem cells while inhibiting the osteoclast differentiation.Moreover,the in vivo rat femoral drilling model demonstrated superior osseointegration three months after implantation.By considering the bone remodeling processes,this study proposes a novel biofunctionalized PEEK surface that regulates the activities of both osteoblasts and osteoclasts to promote osseointegration.
基金supported by National Natural Science Foundation of China(82204766,82074122,82174078)Natural Science Foundation of Hunan province(2023JJ40490)+9 种基金Changjiang Scholars Program in Ministry Education,People’s Republic of China(T2019133)Xiaohe Sci-Tech Talents Special Funding under Hunan Provincial Sci-Tech Talents Sponsorship Program(2023TJ-X71)Science and Technology Innovation Program of Hunan Province(2024RC3201)Scientific research project of Hunan Provincial Education Department(21B0394,21A0239)Research Project of Hunan Administration of Traditional Chinese Medicine(B2023055)Changsha Outstanding Innovative Youth Training Program(kq2306021)Outstanding Youth Program of Hunan University of Chinese Medicine(202202)Postgraduate Innovation Project of Hunan University of Chinese Medicine(2024CX090)Open Foundation Project of Hunan International Joint Laboratory of Traditional Chinese Medicine(2022GJSYS02)Undergraduate Research and Innovation Foundation of Hunan University of Chinese Medicine(2023BKS097).
文摘Abnormal activation of macrophages and osteoclasts(OCs)contributes significantly to rheumatoid arthritis(RA)development by secretion of numerous inflammatory factors.Notably,these cells exhibit significant upregulation of folate receptor proteins on their surfaces.Unfortunately,there is a current lack of safe and effective therapeutic drugs for RA.Xuetongsu(XTS),a triterpenoid compound extracted fromKadsura heteroclita Roxb Craib,has demonstrated the ability to significantly inhibit the proliferation of RA fibroblast-like synoviocytes(RAFLS).However,its clinical application is hampered by poor targeting and short half-life.To address these drawbacks,we previously developed a nano-drug system named HRPS nanoparticles(NPs),which effectively targets RAFLS and inhibits synovial hyperplasia.However,this system overlooked the essential role of OCs in RA-related bone destruction.Therefore,we designed a novel folate-modified biomimetic Prussian blue(PB)-XTS NP(FMPX NP)for the selective delivery of XTS into inflammatory macrophages and OCs.The NP exhibits an excellent photothermal effect when assisted by laser irradiation,facilitating targeted release of XTS within inflammatory macrophages and OCs.The synergistic anti-inflammatory and reactive oxygen species scavenging effects of PB NPs and XTS are mediated by the inhibition of the NF-κB signaling pathway in inflammatory macrophages and RANK/RANKL/NFATc1 signaling pathway in OCs.In vivo experiments showed that FMPX NPs extended the half-life of XTS by 2.32 times,decreased hind foot swelling from 12.10±0.49 mm to 8.24±0.09 mm in the model group,and prevented bone damage.In conclusion,this study introduces a novel dual-targeted nano-based therapy for RA joints and highlights its potential for biochemical photothermal triple therapy for RA.FMPX NPs inhibit arthritis-related inflammation and bone destruction through a dual-target strategy,providing new insights for targeted drug therapies in clinical RA treatment.
基金Supported by The Xuzhou Medical University Affiliated Hospital Development Fund Support Project,No.XYFM202457the 521 Scientific Research Project of Lianyungang City,No.LYG 06521202362.
文摘BACKGROUND This study analyzed the dental follicle and alveolar bone of two patients with tooth eruption disorders,aiming to provide some reference for exploring the etiology and selecting treatment plans of this disease from the perspective of the influence of extracellular matrix on osteoclasts differentiation in dental follicle.CASE SUMMARY Collect dental follicle and alveolar bone tissue from one patient with single tooth eruption disorder and one patient with full permanent tooth eruption disorder,respectively.Simultaneously collect the dental follicle and alveolar bone tissue of obstructed teeth that need to be extracted due to orthodontic treatment as the control group.Hematoxylin and eosin(HE)staining was used to observe the morphology of dental follicle cells.Immunohistochemical staining was used to observe the expression of periostin,receptor activator of nuclear factor kappa B ligand(RANKL),and osteoprotegerin(OPG)protein in dental follicle and alveolar bone tissue.And observe the eruption of teeth after removing resistance from the crown of the permanent tooth germ.CONCLUSION HE staining of two cases of dental follicle tissues showed that the volume of dental follicle cells decreased,the nuclei were condensed,and there seemed to be cellular fibrosis.The immunohistochemical staining showed that both the dental follicle and alveolar bone tissue exhibited increased expression of periostin,decreased expression of RANKL and OPG proteins,and decreased RANKL/OPG ratio.After removing resistance,the permanent tooth germ often appears to have normal eruption.Tooth eruption disorders may be accompanied by abnormal remodeling of periostin,which affects the differentiation function of osteoclasts in the dental follicle and leads to metabolic imbalance of alveolar bone,resulting in tooth eruption disorders.Whether it is a single or full permanent tooth eruption disorder,once the coronal resistance is removed,the teeth can often erupt normally.
基金supported by the National Natural Science Foundation of China(NSFC)(No.82130073,No.82372430,No.31871431,No.31821002,No.32101011,No.22177073)Shanghai Frontiers Science Center of Degeneration and Regeneration in Skeletal System+3 种基金Shanghai Science and Technology Committee(No.23ZR1437600,No.24410710600,No.24141901302)Shenzhen Medical Research Fund(No.B2302005)The Open Project Funding of Shanghai Key Laboratory of Orthopedics(No.KFKT202201)Biomaterials and Regenerative Medicine Institute Cooperative,Research Project,Shanghai Jiao Tong University School of Medicine(No.2022LHA01).
文摘Itaconate,a macrophage-specific anti-inflammatory metabolite,has recently emerged as a critical regulator in rheumatoid arthritis pathogenesis.We found that itaconate is a TNF-αresponsive metabolite significantly elevated in the serum and synovial fluid of rheumatoid arthritis patients and we demonstrated that itaconate is primarily produced by inflammatory macrophages rather than osteoclasts or osteoblasts.In TNF-transgenic and Irg1−/−hybrid mice,a more severe bone destruction phenotype was observed.
基金supported by the National Key R&D Program of China(No.2022YFC2504200)the National Natural Science Foundation of China(Nos.82370936,81920108012,82471032).
文摘Complement C3 plays a critical role in periodontitis.However,its source,role and underlying mechanisms remain unclear.In our study,by analyzing single-cell sequencing data from mouse model of periodontitis,we identified that C3 is primarily derived from periodontal fibroblasts.Subsequently,we demonstrated that C3a has a detrimental effect in ligature-induced periodontitis.C3ar−/−mice exhibited significantly less destruction of periodontal support tissues compared to wild-type mice,characterized by mild gingival tissue damage and reduced alveolar bone loss.This reduction was associated with decreased production of proinflammatory mediators and reduced osteoclast infiltration in the periodontal tissues.Mechanistic studies suggested that C3a could promote macrophage polarization and osteoclast differentiation.Finally,by analyzing single-cell sequencing data from the periodontal tissues of patients with periodontitis,we found that the results observed in mice were consistent with human data.Therefore,our findings clearly demonstrate the destructive role of fibroblast-derived C3 in ligature-induced periodontitis,driven by macrophage M1 polarization and osteoclast differentiation.These data strongly support the feasibility of C3a-targeted interventions for the treatment of human periodontitis.
基金Supported by the National Natural Science Foundation of China,No.82160192and Guangxi Science and Technology Program,No.2023AB23037.
文摘BACKGROUND In vivo degradation of bone scaffolds is significantly influenced by osteoclast(OC)activity,which is orchestrated by the interplay between receptor activator of nuclear factor-kappa B ligand(RANKL)and osteoprotegerin(OPG).The ratio of RANKL/OPG is a crucial determinant of OC-mediated bone resorption,which plays an integral role in bone remodeling and scaffold degradation.Elevated levels of RANKL relative to OPG enhance osteoclastogenesis,thereby accelerating the degradation process essential for integrating bone scaffolds into the host tissue.AIM To elucidate the effects of OPG gene silencing on osteoclastogenesis within rat bone marrow-derived mesenchymal stem cells(BMSCs).By investigating these effects,the study aimed to provide deeper insights into the regulatory mechanisms that influence bone scaffold degradation,potentially leading to improved bone repair and regeneration strategies.METHODS We employed recombinant lentiviral plasmids to silence the OPG gene in rat BMSCs to achieve the aims.The efficacy of gene silencing was assessed using quantitative reverse transcription polymerase chain reaction and western blot analysis to measure the expression levels of OPG and RANKL.Tartrate-resistant acid phosphatase staining was utilized to evaluate the formation of OCs.Additionally,co-immunoprecipitation assays were conducted to explore the interactions between RANKL and OPG proteins,further assessing the biochemical pathways involved in osteoclastogenesis.RESULTS The silencing of the OPG gene in BMSCs resulted in a significant increase in the RANKL/OPG ratio,evidenced by decreased expression levels of OPG and increased levels of RANKL.Enhanced osteoclastogenesis was observed through tartrate-resistant acid phosphatase staining,which indicated a substantial rise in OC formation in response to the altered RANKL/OPG balance.The co-immunoprecipitation assays provided concrete evidence of the direct interaction between RANKL and OPG proteins,substantiating their pivotal roles in regulating OC activity.CONCLUSION The findings from this study underscore the critical role of the RANKL/OPG axis in osteoclastogenesis.Silencing of the OPG gene in BMSCs effectively increases the RANKL/OPG ratio,promoting OC activity and potentially enhancing bone scaffold degradation.This regulatory mechanism offers a promising avenue for modulating bone remodeling processes,which is essential for effective bone repair and the successful integration of bone scaffolds into damaged sites.Future research might focus on optimizing the control of this axis to better facilitate bone tissue engineering and regenerative therapies.
基金support from the National Institute of Health(K99AR081897,R00AR081897)M.N.W.acknowledges funding support from the National Institute of Health(P01DK011794,R01DK116716)+1 种基金the Smith Family Foundation Odyssey Award,and the Chen Institute Massachusetts General Hospital Research Scholar(2024-2029)awardμCT and bone histomorphometry were performed by the Center for Skeletal Research at Massachusetts General Hospital,a NIH-funded program(P30AR066261 and AR075042)led by Mary Bouxsein and Marie Demay).
文摘Osteogenesis imperfecta(OI)is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility.While these disorders have been regarded as defects in osteoblast function,the role of matrix-embedded osteocytes in OI pathogenesis remains largely unknown.Homozygous human SP7(c.946 C>T,R316C)mutation results in a recessive form of OI characterized by fragility fractures,low bone mineral density and osteocyte dendrite defects.To better understand how the OI-causing R316C mutation affects the function of SP7,we generated Sp7^(R342C)knock-in mice.Consistent with patient phenotypes,Sp7^(R342C/R342C)mice demonstrate increased cortical porosity and reduced cortical bone mineral density.Sp7^(R342C/R342C)mice show osteocyte dendrite defects,increased osteocyte apoptosis,and intracortical bone remodeling with ectopic intracortical osteoclasts and elevated osteocyte Tnfsf11 expression.
文摘Objective: To purify and identify the osteoclasts from the tissue of humangiant cell tumor of bone. Methods: We have developed a new method that allows the purification oflarge numbers of authentic osteoclasts (OCs). The OCs were isolated from tissue of human giant celltumor of bone by 0.25% trypsin and collagenase. We characterized OCs in terms of the expression ofdifferent phenotypic markers of OCs. The phenotypic markers of OC included Tartrate-resistant acidphosphatase staining (TRAP). The expression of calcitonin receptor (CTR), cathepsin K and receptoractivator of necrosis factor κB (RANK) mRNA were examined by RT-PCR. Results: The OC cell purifiedby above method functioned normally in vitro. The purity was about 79.7%. They showed the normalosteoclast phenotypes markers of OC. Conclusion: The method provides a system for performingbiochemical and molecular studies of OCs. The study indicates that the method of purifying theosteoclasts from human GCT cell can be used for research of bone metabolism.
基金supported in part by grants from 973 Program from the Chinese Ministry of Science and Technology (MOST) (2014CB964704 and 2015CB964503)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB19000000)the National Natural Science Foundation of China (NSFC) (31371463, 81672119, and 81725010)
文摘The skeleton is a dynamic organ that is constantly remodeled. Proteins secreted from bone cells, namely osteoblasts, osteocytes,and osteoclasts exert regulation on osteoblastogenesis, osteclastogenesis, and angiogenesis in a paracrine manner. Osteoblasts secrete a range of different molecules including RANKL/OPG, M-CSF, SEMA3A, WNT5A, and WNT16 that regulate osteoclastogenesis. Osteoblasts also produce VEGFA that stimulates osteoblastogenesis and angiogenesis. Osteocytes produce sclerostin（SOST） that inhibits osteoblast differentiation and promotes osteoclast differentiation. Osteoclasts secrete factors including BMP6, CTHRC1, EFNB2, S1P, WNT10B, SEMA4D, and CT-1 that act on osteoblasts and osteocytes, and thereby influencea A osteogenesis. Osteoclast precursors produce the angiogenic factor PDGF-BB to promote the formation of Type H vessels, which then stimulate osteoblastogenesis. Besides, the evidences over the past decades show that at least three hormones or ＂osteokines＂from bone cells have endocrine functions. FGF23 is produced by osteoblasts and osteocytes and can regulate phosphate metabolism. Osteocalcin（OCN） secreted by osteoblasts regulates systemic glucose and energy metabolism, reproduction, and cognition. Lipocalin-2（LCN2） is secreted by osteoblasts and can influence energy metabolism by suppressing appetite in the brain.We review the recent progresses in the paracrine and endocrine functions of the secretory proteins of osteoblasts, osteocytes, and osteoclasts, revealing connections of the skeleton with other tissues and providing added insights into the pathogenesis of degenerative diseases affecting multiple organs and the drug discovery process.
基金supported by a grant from the National Natural Science Foundation of China(No.30873290)
文摘The present study aimed at investigating the effects of Puerarin(PR), a major isoflavonoid isolated from the Chinese medicinal herb Puerariae radix, on bone metabolism and the underlying mechanism of action. The in vivo assay, female mice were ovariectomized(OVX), and the OVX mice were fed with a diet containing low, middle, and high doses of PR(2, 4, and 8 mg·d^(-1), respectively) or 17β-estradiol(E_2, 0.03 μg·d^(-1)) for 4 weeks. In OVX mice, the uterine weight declined, and intake of PR at any dose did not affect uterine weight, compared with the control. The total femoral bone mineral density(BMD) was significantly reduced by OVX, which was reversed by intake of the diet with PR at any dose, especially at the low dose. In the in vitro assay, RAW264.7 cells were used for studying the direct effect of PR on the formation of osteoclasts. PR reduced the formation of tartrate resistant acid phosphatase(TRAP)-positive multi-nucleated cells in the RAW 264.7 cells induced by receptor activator for nuclear factor-κB Ligand(RANKL). MC3T3-E1 cells were used for studying the effects of PR on the expression of osteoprotegerin(OPG) and RANKL m RNA expression in osteoblasts. The expression of OPG m RNA and RANKL m RNA was detected by RT-PCR on Days of 5, 7, 10, and 12 after PR exposure. PR time-dependently enhanced the expression of OPG m RNA and reduced the expression of RANKL m RNA in MC3T3-E1 cells. In conclusion, our results suggest that PR can effectively prevent bone loss in OVX mice without any hyperplastic effect on the uterus, and the antiosteoporosis activity of PR may be related to its effects on the formation of osteoclasts and the expression of RANKL OPG in osteoblasts.
文摘Osteoclasts, the bone-resorbing cells, play a pivotal role in skeletal development and adult bone remodeling. They also participate in the pathogenesis of various bone disorders. Osteoclasts differentiate from cells of the monocyte/macrophage lineage upon stimulation of two essential factors, the monocyte/ macrophage colony stimulating factor （M-CSF） and receptor activation of NF-κB ligand （RANKL）. M-CSF binds to its receptor c-Fms to activate distinct signaling pathways to stimulate the proliferation and survival of osteoclast precursors and the mature cell. RANKL, however, is the primary osteoclast differentiation factor, and promotes osteoclast differentiation mainly through controlling gene expression by activating its receptor, RANK. Osteoclast function depends on polarization of the cell, induced by integrin avβ3, to form the resorptive machinery characterized by the attachment to the bone matrix and the formation of the bone-apposed ruffled border. Recent studies have provided new insights into the mechanism of osteoclast differentiation and bone resorption. In particular, c-Fms and RANK signaling have been shown to regulate bone resorption by cross-talking with those activated by integrin avβ3. This review discusses new advances in the understanding of the mechanisms of osteoclast differentiation and function.
基金Supported by(in part)Grants R01-AR43510 to Boyce BF and R01-AR48697 to Xing L from the National Institute of Arthritis and Musculoskeletal and Skin Diseases,United States
文摘Osteoclasts are the bone resorbing cells essential for bone remodeling.Osteoclasts are formed from hematopoietic progenitors in the monocyte/macrophage lineage.Osteoclastogenesis is composed of several steps including progenitor survival,differentiation to mononuclear pre-osteoclasts,fusion to multi-nuclear mature osteoclasts,and activation to bone resorbing osteoclasts.The regulation of osteoclastogenesis has been extensively studied,in which the receptor activator of NF-κB ligand(RANKL)-mediated signaling pathway and downstream transcription factors play essential roles.However,less is known about osteoclast fusion,which is a property of mature osteoclasts and is required for osteoclasts to resorb bone.Several proteins that affect cell fusion have been identified.Among them,dritic cell-specific transmembrane protein(DC-STAMP)is directly associated to osteoclast fusion in vivo.Cytokines and factors influence osteoclast fusion through regula-tion of DC-STAMP.Here we review the recently discovered new factors that regulate osteoclast fusion with specific focus on DC-STAMP.A better understanding of the mechanistic basis of osteoclast fusion will lead to the development of a new therapeutic strategy for bone disorders due to elevated osteoclast bone resorption.Cell-cell fusion is essential for a variety of cellular biological processes.In mammals,there is a limited number of cell types that fuse to form multinucleated cells,such as the fusion of myoblasts for the formation of skeletal muscle and the fusion of cells of the monocyte/macrophage lineage for the formation of multinucleated osteoclasts and giant cells.In most cases,cellcell fusion is beneficial for cells by enhancing function.Myoblast fusion increases myofiber size and diameter and thereby increases contractile strength.Multinucleated osteoclasts have far more bone resorbing activity than their mono-nuclear counterparts.Multinucleated giant cells are much more efficient in the removal of implanted materials and bacteria due to chronic infection than macrophages.Therefore,they are also called foreign-body giant cells.Cell fusion is a complicated process involving cell migration,chemotaxis,cell-cell recognition and attachment,as well as changes into a fusion-competent status.All of these steps are regulated by multiple factors.In this review,we will discuss osteoclast fusion and regulation.
文摘Bone-resorbing osteoclasts are formed from a monocyte/macrophage lineage under the strict control o bone-forming osteoblasts. So far,macrophage colonystimulating factor(M-CSF),receptor activator o nuclear factor-κB ligand(RANKL),and osteoprotegerin(OPG) produced by osteoblasts play major roles in the regulation of osteoclast differentiation. Recent studies have shown that osteoblasts regulate osteoclastogenesis through several mechanisms independent o M-CSF,RANKL,and OPG production. Identification o osteoclast-committed precursors in vivo demonstrated that osteoblasts are involved in the distribution o osteoclast precursors in bone. Interleukin 34(IL-34)a novel ligand for c-Fms,plays a pivotal role in maintaining the splenic reservoir of osteoclast-committed precursors in M-CSF deficient mice. IL-34 is also able to act as a substitute for osteoblast-producing M-CSF in osteoclastogenesis. Wnt5 a,produced by osteoblasts,enhances osteoclast differentiation by upregulating RANK expression through activation of the noncanonical Wnt pathway. Semaphorin 3A produced by osteoblasts inhibits RANKL-induced osteoclast differentiation through the suppression of immunoreceptortyrosine-based activation motif signals. Thus,recent findings show that osteoclast differentiation is tightly regulated by osteoblasts through several different mechanisms. These newly identified molecules are expected to be promising targets of therapeutic agents in bone-related diseases.
基金financially supported by the National Natural Science Foundation of China(No.51801198)the National Key R&D Plan(No.2016YFC1100502).
文摘In this study,the CoCrW-x Cu alloys(x=2,3 and 4 wt%)were fabricated using selective laser melting(abbreviated as Co-2 Cu,Co-3 Cu and Co-4Cu)with the purpose of reducing the inflammation responses and the activity of osteoclast.The metal ions releasing test showed that when the Cu content was less than 4 wt%,the releasing amount of Co and Cr ions was very small;however,when 4 wt%Cu was added in the CoCrW based alloy,the quantity of Co ions was significantly elevated with respect to the other groups due to the segregation of precipitates in the matrix;the Cu2+ion quantity of the Co-2Cu,Co-3Cu and Co-4Cu alloys were 0.05,0.09 and 0.27 g/(L cm2)after 7 d immersion,respectively;the RT-q PCR and ELISA data indicated that the expression levels of the pro-inflammatory cytokines(TNF-αand IL-6)were down-regulated in the Co-3Cu and Co-4Cu groups,whereas the expression level of the anti-inflammatory cytokine(IL-10)was up-regulated in all CoCrW-x Cu alloys;meanwhile,the Cu-containing CoCrW alloys significantly down-regulated the expression of the NF-B signal pathway in a Cu content-dependent manner,and the downstream transcription factors of NF-B signal pathway including NFATc1,TRAP and Cath-K were also down-regulated via potentially manipulating the NF-B signal pathway.After comprehensive consideration,it is considered that the Co-3Cu alloy is a potential material for self-alleviating inflammatory responses.
基金supported by grants from the National Key Research and Development Program of China (2020YFC2002800 to J.L. and 2018YFC1105102 to J.L.)the National Natural Science Foundation of China (91949127, 92168204 to J.L.)the Fundamental Research Funds for the Central Universities (22120210586)
文摘Prostaglandin E2(PGE2), a major cyclooxygenase-2(COX-2) product, is highly secreted by the osteoblast lineage in the subchondral bone tissue of osteoarthritis(OA) patients. However, NSAIDs, including COX-2 inhibitors, have severe side effects during OA treatment. Therefore, the identification of novel drug targets of PGE2 signaling in OA progression is urgently needed. Osteoclasts play a critical role in subchondral bone homeostasis and OA-related pain. However, the mechanisms by which PGE2 regulates osteoclast function and subsequently subchondral bone homeostasis are largely unknown. Here, we show that PGE2 acts via EP4 receptors on osteoclasts during the progression of OA and OA-related pain. Our data show that while PGE2 mediates migration and osteoclastogenesis via its EP2 and EP4 receptors, tissue-specific knockout of only the EP4 receptor in osteoclasts(EP4 Lys M) reduced disease progression and osteophyte formation in a murine model of OA. Furthermore, OA-related pain was alleviated in the EP4 Lys M mice, with reduced Netrin-1 secretion and CGRP-positive sensory innervation of the subchondral bone. The expression of plateletderived growth factor-BB(PDGF-BB) was also lower in the EP4 Lys Mmice, which resulted in reduced type H blood vessel formation in subchondral bone. Importantly, we identified a novel potent EP4 antagonist, HL-43, which showed in vitro and in vivo effects consistent with those observed in the EP4 Lys Mmice. Finally, we showed that the Gαs/PI3 K/AKT/MAPK signaling pathway is downstream of EP4 activation via PGE2 in osteoclasts. Together, our data demonstrate that PGE2/EP4 signaling in osteoclasts mediates angiogenesis and sensory neuron innervation in subchondral bone, promoting OA progression and pain, and that inhibition of EP4 with HL-43 has therapeutic potential in OA.
文摘Giant cell tumors of the pancreas come in three varieties-osteoclastic,pleomorphic,and mixed histology.These tumors have distinctive endoscopic,clinical,and cytological features.Giant cell tumors have a controversial histogenesis,with some authors favoring an epithelial origin and others favoring a mesenchymal origin.The true origin of these lesions remains unclear at this time.These are also very rare tumors but proper identification and differentiation from more common pancreatic adenocarcinoma is important.The risk factors of these tumors and the prognosis may be different from those associated with standard pancreatic adenocarcinoma.Recognition of these differences can significantly affect patient care.These lesions have a unique appearance when imaged with endoscopic ultrasound(EUS),and these lesions can be diagnosed via EUS guided Fine Needle Aspiration(FNA).This manuscript will review the endoscopic,clinical,and pathologic features of these tumors.
基金supported by grants from the National Natural Science Foundation Projects of China(81822012,81771043)National Science and Technology Major Project of China(2016YFC1102705)+1 种基金Special Fund of Chinese Central University for Basic Scientific Research(20173386)Training Program of Shanghai Municipal Health System for Excellent Talents(2017BR009)。
文摘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(lnc RNAs)are a newly identified class of functional RNAs that regulate cellular processes,such as gene expression and translation regulation.Recently,lnc RNAs 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 lnc RNAs in osteoclast formation and bone resorption urgently needs to be clarified.We recently found that the lnc RNA 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 c TG)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 lnc RNAs could be potential targets to regulate osteoclastogenesis and orthodontic tooth movement speed in the clinic in the future.
