Chinese dwarf cherry(Cerasus humilis)is a fruit unique to China,which is considered to have osteoprotective effects.However,no systematic experimental characterization was available.In this study,the osteoprotective a...Chinese dwarf cherry(Cerasus humilis)is a fruit unique to China,which is considered to have osteoprotective effects.However,no systematic experimental characterization was available.In this study,the osteoprotective activity and mechanism of Chinese dwarf cherry polyphenol extract(OPE)was studied.In vitro,OPE stimulated the alkaline phosphatase activity in the early differentiation stage,increased the osteocalcin level in the middle differentiation stage,and induced the formation of more bonemineralized nodules in the late osteogenic stage.In vivo,OPE improved cancellous bone structure and maximum load of the femur in ovariectomized(OVX)rats.The balance between bone formation and resorption was regulated.Oxidative stress levels in the peripheral blood,liver and femur were reduced.OPE alleviated the disturbance in energy metabolism,muscle development,and muscle regulation-related signaling pathways caused by OVX and activated the calcium/adenosine monophosphate-activated protein kinase signaling pathway.Therefore,OPE is a potential dietary supplement for the prevention and treatment of osteoporosis.展开更多
The delicate balance between bone formation by osteoblasts and bone resorption by osteoclasts maintains bone homeostasis.Nuclear receptors(NRs)are now understood to be crucial in bone physiology and pathology.However,...The delicate balance between bone formation by osteoblasts and bone resorption by osteoclasts maintains bone homeostasis.Nuclear receptors(NRs)are now understood to be crucial in bone physiology and pathology.However,the function of the Farnesoid X receptor(FXR),a member of the NR family,in regulating bone homeostasis remains incompletely understood.In this study,in vitro and in vivo models revealed delayed bone development and an osteoporosis phenotype in mice lacking FXR in bone marrow mesenchymal stem cells(BMSCs)and osteoblasts due to impaired osteoblast differentiation.Mechanistically,FXR could stabilize RUNX2 by inhibiting Thoc6-mediated ubiquitination,thereby promoting osteogenic activity in BMSCs.Moreover,activated FXR could directly bind to the Thoc6 promoter,suppressing its expression.The interaction between RUNX2 and Thoc6 was mediated by the Runt domain of RUNX2 and the WD repeat of Thoc6.Additionally,Obeticholic acid(OCA),an orally available FXR agonist,could ameliorate bone loss in an ovariectomy(OVX)-induced osteoporotic mouse model.Taken together,our findings suggest that FXR plays pivotal roles in osteoblast differentiation by regulating RUNX2 stability and that targeting FXR may be a promising therapeutic approach for osteoporosis.展开更多
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
Neural EGFL-like 2(NELL2)is a secreted protein known for its regulatory functions in the nervous and reproductive systems,yet its role in bone biology remains unexplored.In this study,we observed that NELL2 was dimini...Neural EGFL-like 2(NELL2)is a secreted protein known for its regulatory functions in the nervous and reproductive systems,yet its role in bone biology remains unexplored.In this study,we observed that NELL2 was diminished in the bone of aged and ovariectomized(OVX)mice,as well as in the serum of osteopenia and osteoporosis patients.In vitro loss-of-function and gain-offunction studies revealed that NELL2 facilitated osteoblast differentiation and impeded adipocyte differentiation from stromal progenitor cells.In vivo studies further demonstrated that the deletion of NELL2 in preosteoblasts resulted in decreased cancellous bone mass in mice.Mechanistically,NELL2 interacted with the FNI-type domain located at the C-terminus of Fibronectin 1(Fn1).Moreover,we found that NELL2 activated the focal adhesion kinase(FAK)/AKT signaling pathway through Fn1/integrinβ1(ITGB1),leading to the promotion of osteogenesis and the inhibition of adipogenesis.Notably,administration of NELL2-AAV was found to ameliorate bone loss in OVX mice.These findings underscore the significant role of NELL2 in osteoblast differentiation and bone homeostasis,suggesting its potential as a therapeutic target for managing osteoporosis.展开更多
Membrane-initiated estrogen receptorα(mERα)signaling has been shown to affect bone mass in murine models.However,it remains unknown which cell types mediate the mERα-dependent effects on bone.In this study,we gener...Membrane-initiated estrogen receptorα(mERα)signaling has been shown to affect bone mass in murine models.However,it remains unknown which cell types mediate the mERα-dependent effects on bone.In this study,we generated a novel mouse model with a conditional C451A mutation in Esr1,which enables selective knockout of the palmitoylation site essential for the membrane localization of ERα(C451A^(f/f)).First,we used Runx2-Cre mice to generate Runx2-C451A^(f/f)mice with conditional inactivation of mERαsignaling in Runx2-expressing osteoblast lineage cells.No significant changes were observed in body weight,weights of estrogen-responsive organs,or serum concentrations of estradiol between female Runx2-C451A^(f/f)and homozygous C451A^(f/f)littermate controls.High-resolution microcomputed tomography analysis showed a consistent decrease in cortical bone mass in the tibia,femur,and vertebra L5 of Runx2-C451A^(f/f)mice and three-point bending analysis of humerus revealed an impaired mechanical bone strength in Runx2-C451A^(f/f)female mice compared to controls.Additionally,primary osteoblast cultures from mice lacking mERαsignaling showed impaired differentiation compared to controls.展开更多
There is a worldwide epidemic of skeletal diseases causing not only a public health issue but also accounting for a sizable portion of healthcare expenditures. The vertebrate skeleton is known to be formed by mesenchy...There is a worldwide epidemic of skeletal diseases causing not only a public health issue but also accounting for a sizable portion of healthcare expenditures. The vertebrate skeleton is known to be formed by mesenchymal cells condensing into tissue elements(patterning phase) followed by their differentiation into cartilage(chondrocytes) or bone(osteoblasts) cells within the condensations. During the growth and remodeling phase, bone is formed directly via intramembranous ossification or through a cartilage to bone conversion via endochondral ossification routes. The canonical pathway of the endochondral bone formation process involves apoptosis of hypertrophic chondrocytes followed by vascular invasion that brings in osteoclast precursors to remove cartilage and osteoblast precursors to form bone. However, there is now an emerging role for chondrocyte-to-osteoblast transdifferentiation in the endochondral ossification process. Although the concept of "transdifferentiation" per se is not recent,new data using a variety of techniques to follow the fate of chondrocytes in different bones during embryonic and post-natal growth as well as during fracture repair in adults have identified three different models for chondrocyte-to-osteoblast transdifferentiation(direct transdifferentiation, dedifferentiation to redifferentiation, and chondrocyte to osteogenic precursor). This review focuses on the emerging models of chondrocyte-to-osteoblast transdifferentiation and their implications for the treatment of skeletal diseases as well as the possible signaling pathways that contribute to chondrocyte-to-osteoblast transdifferentiation processes.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
AIM: Osteoblasts are key functional cells in the process of bone metabolic balance. Phytoestrogens have an important influence on the proliferation and differentiation of osteoblasts. Puerarin, a plant estrogen, has a...AIM: Osteoblasts are key functional cells in the process of bone metabolic balance. Phytoestrogens have an important influence on the proliferation and differentiation of osteoblasts. Puerarin, a plant estrogen, has a wide range concentration in vitro on the function of osteoblasts. The current study investigates the effect of the phytoestrogen puerarin on the proliferation, differentiation, and mineralization of osteoblasts in vitro. METHODS: The calvaria bone of eight-ten Wistar rats which were born within 24 h were obtained in aseptic condition. After enzyme digestion, isolation, purified osteoblasts of rats were cultured for further study. The cells of the first to third generation were divided into a control group and a puerarin-treated group with 10-3–10-10 mol·L-1 puerarin. The cells were exposed to the medium containing a low level of carbohydrates, 10%(V/V) FBS for 24 h. After 1 to 4 days of culture, the OD values on the proliferation of osteoblasts in each group were determined by microplate reader. The cells were cultured in the medium containing 50 μg·mL-1 vitamin C, 10-2 mol·L-1 sodium glycerophosphate, 10% FBS and the medium was changed every 3 to 4 days. After 2 to 8 days of culture, expression of alkaline phosphatase were tested and compared by microplate reader. The mineral nodes of osteoblasts were dyed using alizarin red or improved Von Kossa way after four weeks. RESULTS: Compared with those in the 10-5–10-9 mol·L-1 puerarin, the proliferation of osteoblasts, the expression of alkaline phosphatase, and the number of mineral nodes of osteoblasts were significantly decreased in the control group. The increase was the fastest in the third day, while on the fourth day it was decreased, and arrived at statistical significance compared with the alkaline phosphatase activities and control group. The 10-6 mol·L-1 group was the most distinct, and formed the most mineralized nodule. Compared with the 10-3 mol·L-1 puerarin group, those changes were markedly increased in the control group. CONCLUSIONS: Puerarin has proliferation, differentiation, and mineralization effects on osteoblasts in a dose-dependent manner, and has a double-way effect on the osteoblasts in vitro. A low-dose showed positive effects on the development of osteoblasts, and high-dose puerarin could inhibit the formation of bone.展开更多
Objective To observe the effects of two main isoflavones, daidzein and genistein on the bone-nodule formation in rat calvaria osteoblasts in vitro. Methods Osteoblasts obtained from newborn Sprague-dawley rat calvaria...Objective To observe the effects of two main isoflavones, daidzein and genistein on the bone-nodule formation in rat calvaria osteoblasts in vitro. Methods Osteoblasts obtained from newborn Sprague-dawley rat calvarias were cultured for several generations. The second generation cells were cultured in Minimum Essential Medium supplemented with ascorbic acid and Na-beta-glycerophosphate for several days, in the presence of daidzein and genistein, with or without the estrogen receptor antagonist ICI 182780. Number of nodules was counted at the end of the incubation period (day 20) by staining with Alizarin Red S calcium stain. The release of osteocalcin, as a marker of osteoblast activity, was also determined on day 7 and day 12 during the incubation period. Results Compared with the control, the numbers of nodules were both increased by incubation with daidzein and genistein. 17β-estradiol was used as a positive control and proved to be a more effective inducer of the increase in bone-nodules formation than daidzein and genistein. The release of osteocalcin into culture media was also increased in the presence of daidzein and genistein, as well as 17β-estradiol on day 7 and day 12 (day 12 were higher). The estrogen receptor antagonist ICI 182780 completely blocked the genistein- and 17β-estradiol-induced increase of nodule numbers and osteocalcin release in osteoblasts. However, the effects induced by daidzein could not be inhibited by ICI 182780. Conclusion These findings suggest that geinistein can stimulate bone-nodule formation and increase the release of osteocalcin in rat osteoblasts. The effects, like those induced by 17β-estradiol, are mediated by the estrogen receptor dependent pathway. Daidzein also can stimulate bone-nodule formation and increase the release of osteocalcin in rat osteoblasts, but it is not, at least not merely, mediated by the estrogen receptor dependent pathway.展开更多
INTRODUCTIONThe transforming growth factor-β （TGF-β） superfamily com- prises TGF-βs, Activin, bone morphogenetic proteins （BMPs） and other related proteins. TGF-β superfamily members act through a heteromeric ...INTRODUCTIONThe transforming growth factor-β （TGF-β） superfamily com- prises TGF-βs, Activin, bone morphogenetic proteins （BMPs） and other related proteins. TGF-β superfamily members act through a heteromeric receptor complex,, comprised of type I and type II receptors at the cell surface that transduce intracellular signals via Smad complex or mitogen-activated protein kinase （MAPK） cascade.展开更多
There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy(HRT). The present study was designed to investigate the in vitro effects of estrogen-like activitie...There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy(HRT). The present study was designed to investigate the in vitro effects of estrogen-like activities of two widespread coumarins, osthole and imperatorin, using the MCF-7 cell proliferation assay and their alkaline phosphatase(ALP) activities in osteoblasts Saos-2 cells. The two compounds were found to strongly stimulate the proliferation of MCF-7 cells. The estrogen receptor-regulated ERα, progesterone receptor(PR) and PS2 m RNA levels were increased by treatment with osthole and imperatorin. All these effects were significantly inhibited by the specific estrogen receptor antagonist ICI182, 780. Cell cycle analysis revealed that their proliferation stimulatory effect was associated with a marked increase in the number of MCF-7 cells in S phase, which was similar to that observed with estradiol. It was also observed that they significantly increased ALP activity, which was reversed by ICI182,780. These results suggested that osthole and imperatorin could stimulate osteoblastic activity by displaying estrogenic properties or through the ER pathway. In conclusion, osthole and imperatorin may represent new pharmacological tools for the treatment of osteoporosis.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 the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrol...In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching （EE）. MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched （SEA） as well as Machined （M） surfaces respectively. The results show signifi- cant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.展开更多
Silicon （Si） incorporated porous TiO2 coating （Si-TiO2） prepared on titanium （Ti） by micro-arc oxidation （MAO） technique was demonstrated to be cytocompatible in previous studies. In view of the potential clin...Silicon （Si） incorporated porous TiO2 coating （Si-TiO2） prepared on titanium （Ti） by micro-arc oxidation （MAO） technique was demonstrated to be cytocompatible in previous studies. In view of the potential clinical applications, a detailed in vitro study of the biological activity of Si-Ti02 coating, in terms of osteoblast （MC3T3-EI cells） morphology, proliferation, differentiation and mineralization was performed. Immunofluo- rescent staining indicated that cells seeded on the Si-TiO2 coating showed improved adhesion with developing mature cytoskeletons, which contained numerous distinct and well-defined actin stress fibers in the cell mem- branes compared with those on the Ti02 coating and Ti plate. Results from proliferation assay showed that the proliferation rate of cells seeded on the Si-TiO2coating was significantly faster than that on the TiO2 coating and Ti plate. Furthermore, the analysis of osteogenic gene expression demonstrated that the Si-Ti02 coating stimulated the expression of osteoblast-related genes and promoted differentiation and mineralization of MC3T3-EI cells. In addition, the Si-TiO2 coating differentially regulated Wnt signaling pathway by up-regulating the expression of low-density lipoprotein （LDL） receptor-related protein 5 （LrpS）, and downregulating the expression of Dickkopf-1 （Dkkl）. All together, these results indicate that the investigated titanium with Si-TiO2 coating is biocompatible and a good candidate material used as implants.展开更多
Aim Given the well-known properties of Schwann cells in promoting nerve regeneration, transplanting Schwann cells into implant sockets might be an effective method to promote sensory responses of osseointegrated impla...Aim Given the well-known properties of Schwann cells in promoting nerve regeneration, transplanting Schwann cells into implant sockets might be an effective method to promote sensory responses of osseointegrated implants. The aim of this study was to evaluate the interaction between Schwann cells and osteoblasts. Methodology Schwann cells derived from the sciatic nerves of neonatal rat were co-culured with osteoblasts using Transwell inserts. The proliferation of Schwann cells in the co-culture system was evaluated using methylthiazol tetrazolium （MTT） colorimetric method. Moreover, the secretions and mRNA levels of brain-derived neurotrophic factor （BDNF） and nerve growth factor （NGF） were measured by enzyme-linked immunosorbent assay （ELISA） and quantitative real-time PCR, respectively. In order to test the effect of Schwann cells on osteoblasts, alkaline phosphatase （ALP） staining and Alizerin red staining were performed as well. Results Schwann cells, which were co-cultured with the osteoblasts, showed an intact proliferation during the observation period. Moreover, the gene expression and synthesis of BDNF and NGF were not impaired by the osteoblasts. Meanwhile, co-cultured osteoblasts exhibited a significant increase in the proliferation on day 3 and 6 （P〈 0.05）. Co-culture of these two types of cells also led to a more intense staining of ALP and an elevated number of calcified nodules. Conclusion These findings demonstrate that, in the in vitro indirect co-culture environment, Schwann cells can maintain their normal ability to synthesize neurotrophins, which then enhance the proliferation and differentiation of osteoblasts.展开更多
Objective To study large-scale expansion of SD （Sprague-Dawley） rat＇s osteoblasts in suspension culture in a rotating wall vessel bioreactor （RWVB）. Methods The bioreactor rotation speeds were adjusted in the ran...Objective To study large-scale expansion of SD （Sprague-Dawley） rat＇s osteoblasts in suspension culture in a rotating wall vessel bioreactor （RWVB）. Methods The bioreactor rotation speeds were adjusted in the range of 0 to 20 rpm, which could provide low shear on the rnicrocarriers around 1 dyn/cm^2. The cells were isolated via sequential digestions of neonatal （less than 3 days old） SD rat calvaria. After the primary culture and several passages, the cells were seeded onto the microcarriers and cultivated in T-flask, spinner flask and RWVB respectively. During the culture period, the cells were counted and observed under the inverted microscope for morphology every 12 h. After 7 days, the cells were evaluated with scanning electron microscope （SEM） for histological examination of the aggregates. Also, the hematoxylin-eosin （HE） staining and alkaline phosphatase （ALP） staining were performed. Moreover, von-Kossa staining and Alizarin Red S staining were carded out for mineralized nodule formation. Results The results showed that in RWVB, the cells could be expanded by more than ten times and they presented better morphology and vitality and stronger ability to form bones. Conclusions The developed RWVB can provide the culture environment with a relatively low shear force and necessary three-dimensional （3D） interactions among cells and is suitable for osteopath expansion in vitro.展开更多
RANKL signaling is essential for osteoclastogenesis. Its role in osteoblastic differentiation and bone formation is unknown. Here we demonstrate that RANK is expressed at an early stage of bone marrow mesenchymal stem...RANKL signaling is essential for osteoclastogenesis. Its role in osteoblastic differentiation and bone formation is unknown. Here we demonstrate that RANK is expressed at an early stage of bone marrow mesenchymal stem cells(BMSCs) during osteogenic differentiation in both mice and human and decreased rapidly. RANKL signaling inhibits osteogenesis by promoting β-catenin degradation and inhibiting its synthesis. In contrast, RANKL signaling has no significant effects on adipogenesis of BMSCs.Interestingly, conditional knockout of rank in BMSCs with Prx1-Cre mice leads to a higher bone mass and increased trabecular bone formation independent of osteoclasts. In addition, rank: Prx1-Cre mice show resistance to ovariectomy-(OVX) induced bone loss. Thus, our results reveal that RANKL signaling regulates both osteoclasts and osteoblasts by inhibition of osteogenic differentiation of BMSCs and promotion of osteoclastogenesis.展开更多
The effects of lanthanum （Ⅲ） on the bone resorbing activity of rabbit mature osteoclasts （OCs） in the presence of osteoblasts （OBs） were studied in vitro by measuring the number and area of absorption pits. La...The effects of lanthanum （Ⅲ） on the bone resorbing activity of rabbit mature osteoclasts （OCs） in the presence of osteoblasts （OBs） were studied in vitro by measuring the number and area of absorption pits. La（ Ⅲ ） at concentrations ranging from 1.00 × 10^-5 to 1.00 × 10^-8 mol·L^-1 show no effect on mature OC number （P 〉 0.05）. In the OC-OB coculture systems without La（Ⅲ ）, osteoblasts alone did not influence the pit number and area whether the two kinds of cells were in contact or not （ P 〉 0.05）. Under the OC-OB not-in-contact condition, the effect of La（ Ⅲ ） on the bone-resorbing activity of OCs was similar to that of La（Ⅲ） in the absence of OBs （P 〉 0.05）. However, while OCs were in direct contact with OBs, the inhibitory effects of La（ Ⅲ ） on OCs＇ bone-resorbing activity decreased at the concentrations of 1.00 × 10^-5, 1.00×10^-6 and 1.00×10^-7mol·L^-1, and the promotion effects increased at 1.00×10^-8mol·L^-1 （P 〈0.05）. The results suggest that direct cell-cell contact between OC and OB be essential for OBs to play their role in regulating the response of OCs to La（ Ⅲ ）.展开更多
OBJECTIVE:To explore the relationship between autophagy and apoptosis regulated by puerarin during osteoblastogenesis.METHODS:In this study,the effects of puerarin on the autophagic activity and apoptosis level of ost...OBJECTIVE:To explore the relationship between autophagy and apoptosis regulated by puerarin during osteoblastogenesis.METHODS:In this study,the effects of puerarin on the autophagic activity and apoptosis level of osteoblast precursors(MC3T3-E1 cells)was observed.Subsequently,the roles of puerarin on B-cell lymphoma-2(Bcl-2)phosphorylation at different sites in osteoblast precursors were observed.The effect of puerarin on the interaction between Bcl-2 and autophagy regulatory molecule or pro-apoptotic molecule was also investigated using Co-immunoprecipitation assays.In addition,the effect of puerarin on mitochondrial membrane potential of osteoblast precursors was also identified by mitochondrial membrane potential fluorescence probe assays.RESULTS:Our results showed that puerarin can promote the autophagic activity and apoptosis level of MC3T3-E1cells.In addition,puerarin promoted Bcl-2phosphorylation at Ser70 site,and the dissociation of Bcl-2-Beclin1 complex.Moreover,puerarin could enhance the binding of Bcl-2-Bcl-2-Associated X(Bax)complex in MC3T3-E1 cells.Furthermore,puerarin increased the mitochondrial membrane potential of MC3T3-E1 cells.CONCLUSIONS:Therefore,puerarin promotes Beclin1into autophagy flux through Bcl-2 phosphorylation at Ser70,thereby enhancing autophagy of osteoblast precursors,which mediates its anti-apoptotic role during osteoblastogenesis.Furthermore,the dissociation of Bcl-2-Beclin1 complex is conducive to the binding of Bcl-2-Bax complex,which resists the apoptosis of osteoblast precursors via the increased mitochondrial membrane potential.展开更多
Summary: Rat transforming growth factor β1 (rTGFβ1) cDNA from rat lymphocytes was cloned by RT-PCR and inserted into pcDNA3 to construct an eukaryotic expression vector, which was named pcDNA3-TGFβ1. The cloned gen...Summary: Rat transforming growth factor β1 (rTGFβ1) cDNA from rat lymphocytes was cloned by RT-PCR and inserted into pcDNA3 to construct an eukaryotic expression vector, which was named pcDNA3-TGFβ1. The cloned gene was confirmed to code rat TGFβ1 by restriction enzyme analysis. pcDNA3-TGFβ1 plasmid was transfected into rat osteoblasts by using liposome-mediated gene transfer technique and the expression of TGFβ1 was detected by using irnmunohistochemical staining assay. It was found that the rat TGFβ1 expression product was obviously detectable in the transfected osteoblasts in 48 h. High expression of TGFβ1 was obtained in the rat osteoblasts in which the constructed TGFβ1 expression vector was transfected.展开更多
基金supported by the National Natural Science Foundation of China(32470399)Beijing Natural Science Foundation(5212014)Key Research and Development Program in the Ningxia Hui Autonomous Region,China(2020BBF02027).
文摘Chinese dwarf cherry(Cerasus humilis)is a fruit unique to China,which is considered to have osteoprotective effects.However,no systematic experimental characterization was available.In this study,the osteoprotective activity and mechanism of Chinese dwarf cherry polyphenol extract(OPE)was studied.In vitro,OPE stimulated the alkaline phosphatase activity in the early differentiation stage,increased the osteocalcin level in the middle differentiation stage,and induced the formation of more bonemineralized nodules in the late osteogenic stage.In vivo,OPE improved cancellous bone structure and maximum load of the femur in ovariectomized(OVX)rats.The balance between bone formation and resorption was regulated.Oxidative stress levels in the peripheral blood,liver and femur were reduced.OPE alleviated the disturbance in energy metabolism,muscle development,and muscle regulation-related signaling pathways caused by OVX and activated the calcium/adenosine monophosphate-activated protein kinase signaling pathway.Therefore,OPE is a potential dietary supplement for the prevention and treatment of osteoporosis.
基金supported by National Natural Science Foundation of China(grant numbers 82072523 to Zhiyong Hou)Postdoctoral program of Clinical medicine of Hebei Medical University(grant numbers PD2023012 to Sujuan Xu)+2 种基金Excellent postdoctoral research funding project of Hebei Province(grant numbers B2023005011 to Sujuan Xu)The 16th special grant of China Postdoctoral Science Foundation(grant numbers 2023T160182 to Sujuan Xu)Natural Science Foundation of Hebei Province,China(grant numbers H2023206230 to Yingchao Yin,H2024206186 to Sujuan Xu).
文摘The delicate balance between bone formation by osteoblasts and bone resorption by osteoclasts maintains bone homeostasis.Nuclear receptors(NRs)are now understood to be crucial in bone physiology and pathology.However,the function of the Farnesoid X receptor(FXR),a member of the NR family,in regulating bone homeostasis remains incompletely understood.In this study,in vitro and in vivo models revealed delayed bone development and an osteoporosis phenotype in mice lacking FXR in bone marrow mesenchymal stem cells(BMSCs)and osteoblasts due to impaired osteoblast differentiation.Mechanistically,FXR could stabilize RUNX2 by inhibiting Thoc6-mediated ubiquitination,thereby promoting osteogenic activity in BMSCs.Moreover,activated FXR could directly bind to the Thoc6 promoter,suppressing its expression.The interaction between RUNX2 and Thoc6 was mediated by the Runt domain of RUNX2 and the WD repeat of Thoc6.Additionally,Obeticholic acid(OCA),an orally available FXR agonist,could ameliorate bone loss in an ovariectomy(OVX)-induced osteoporotic mouse model.Taken together,our findings suggest that FXR plays pivotal roles in osteoblast differentiation by regulating RUNX2 stability and that targeting FXR may be a promising therapeutic approach for osteoporosis.
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 grants from National Natural Science Foundation of China(82272444,81972031,81972033)China Postdoctoral Science Foundation(2022M722382)Tianjin Key Medical Discipline(Specialty)Construction Project(TJYXZDXK-032A)。
文摘Neural EGFL-like 2(NELL2)is a secreted protein known for its regulatory functions in the nervous and reproductive systems,yet its role in bone biology remains unexplored.In this study,we observed that NELL2 was diminished in the bone of aged and ovariectomized(OVX)mice,as well as in the serum of osteopenia and osteoporosis patients.In vitro loss-of-function and gain-offunction studies revealed that NELL2 facilitated osteoblast differentiation and impeded adipocyte differentiation from stromal progenitor cells.In vivo studies further demonstrated that the deletion of NELL2 in preosteoblasts resulted in decreased cancellous bone mass in mice.Mechanistically,NELL2 interacted with the FNI-type domain located at the C-terminus of Fibronectin 1(Fn1).Moreover,we found that NELL2 activated the focal adhesion kinase(FAK)/AKT signaling pathway through Fn1/integrinβ1(ITGB1),leading to the promotion of osteogenesis and the inhibition of adipogenesis.Notably,administration of NELL2-AAV was found to ameliorate bone loss in OVX mice.These findings underscore the significant role of NELL2 in osteoblast differentiation and bone homeostasis,suggesting its potential as a therapeutic target for managing osteoporosis.
基金supported by the Swedish Research Council(2017-01286,2020-01840)the Swedish state under the agreement between the Swedish government and the county councils(ALF-agreement)(ALFGBG721581)+2 种基金the Gustaf V 80-years fund(FAI-2018-0466)the IngaBritt and Arne Lundberg Foundation(LU2017-0076)the Novo Nordisk Foundation(26844).
文摘Membrane-initiated estrogen receptorα(mERα)signaling has been shown to affect bone mass in murine models.However,it remains unknown which cell types mediate the mERα-dependent effects on bone.In this study,we generated a novel mouse model with a conditional C451A mutation in Esr1,which enables selective knockout of the palmitoylation site essential for the membrane localization of ERα(C451A^(f/f)).First,we used Runx2-Cre mice to generate Runx2-C451A^(f/f)mice with conditional inactivation of mERαsignaling in Runx2-expressing osteoblast lineage cells.No significant changes were observed in body weight,weights of estrogen-responsive organs,or serum concentrations of estradiol between female Runx2-C451A^(f/f)and homozygous C451A^(f/f)littermate controls.High-resolution microcomputed tomography analysis showed a consistent decrease in cortical bone mass in the tibia,femur,and vertebra L5 of Runx2-C451A^(f/f)mice and three-point bending analysis of humerus revealed an impaired mechanical bone strength in Runx2-C451A^(f/f)female mice compared to controls.Additionally,primary osteoblast cultures from mice lacking mERαsignaling showed impaired differentiation compared to controls.
基金supported by funding from the National Institutes of Arthritis and Musculoskeletal Diseases RO1 grant (AR048139)Veterans Administration BLR&D merit review grant (101-BX-001396) to S.M
文摘There is a worldwide epidemic of skeletal diseases causing not only a public health issue but also accounting for a sizable portion of healthcare expenditures. The vertebrate skeleton is known to be formed by mesenchymal cells condensing into tissue elements(patterning phase) followed by their differentiation into cartilage(chondrocytes) or bone(osteoblasts) cells within the condensations. During the growth and remodeling phase, bone is formed directly via intramembranous ossification or through a cartilage to bone conversion via endochondral ossification routes. The canonical pathway of the endochondral bone formation process involves apoptosis of hypertrophic chondrocytes followed by vascular invasion that brings in osteoclast precursors to remove cartilage and osteoblast precursors to form bone. However, there is now an emerging role for chondrocyte-to-osteoblast transdifferentiation in the endochondral ossification process. Although the concept of "transdifferentiation" per se is not recent,new data using a variety of techniques to follow the fate of chondrocytes in different bones during embryonic and post-natal growth as well as during fracture repair in adults have identified three different models for chondrocyte-to-osteoblast transdifferentiation(direct transdifferentiation, dedifferentiation to redifferentiation, and chondrocyte to osteogenic precursor). This review focuses on the emerging models of chondrocyte-to-osteoblast transdifferentiation and their implications for the treatment of skeletal diseases as well as the possible signaling pathways that contribute to chondrocyte-to-osteoblast transdifferentiation processes.
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 the Program for New Century Excellent Talents in University(No.NCET-13-0954)the Changjiang Scholars and Innovative Research Team in University(No.IRT1174),the National Natural Science Foundation of China(Nos.J1210063,81001622,81073029)+3 种基金the project"As a Major New Drug to Create a Major National Science and Technology Special"(Nos.2011ZX09401-308-034,2014ZX09304-307-02)the China Postdoctoral Science Foundation(No.2012M521831),the Key Program for the International S&T Cooperation Projects of Shaanxi Province(No.2013KW31-01)the Natural Science Foundation of Shaanxi Provincial Education Department(No.2013JK0811)the Administration of Traditional Chinese Medicine of Shaanxi(No.13-ZY006)
文摘AIM: Osteoblasts are key functional cells in the process of bone metabolic balance. Phytoestrogens have an important influence on the proliferation and differentiation of osteoblasts. Puerarin, a plant estrogen, has a wide range concentration in vitro on the function of osteoblasts. The current study investigates the effect of the phytoestrogen puerarin on the proliferation, differentiation, and mineralization of osteoblasts in vitro. METHODS: The calvaria bone of eight-ten Wistar rats which were born within 24 h were obtained in aseptic condition. After enzyme digestion, isolation, purified osteoblasts of rats were cultured for further study. The cells of the first to third generation were divided into a control group and a puerarin-treated group with 10-3–10-10 mol·L-1 puerarin. The cells were exposed to the medium containing a low level of carbohydrates, 10%(V/V) FBS for 24 h. After 1 to 4 days of culture, the OD values on the proliferation of osteoblasts in each group were determined by microplate reader. The cells were cultured in the medium containing 50 μg·mL-1 vitamin C, 10-2 mol·L-1 sodium glycerophosphate, 10% FBS and the medium was changed every 3 to 4 days. After 2 to 8 days of culture, expression of alkaline phosphatase were tested and compared by microplate reader. The mineral nodes of osteoblasts were dyed using alizarin red or improved Von Kossa way after four weeks. RESULTS: Compared with those in the 10-5–10-9 mol·L-1 puerarin, the proliferation of osteoblasts, the expression of alkaline phosphatase, and the number of mineral nodes of osteoblasts were significantly decreased in the control group. The increase was the fastest in the third day, while on the fourth day it was decreased, and arrived at statistical significance compared with the alkaline phosphatase activities and control group. The 10-6 mol·L-1 group was the most distinct, and formed the most mineralized nodule. Compared with the 10-3 mol·L-1 puerarin group, those changes were markedly increased in the control group. CONCLUSIONS: Puerarin has proliferation, differentiation, and mineralization effects on osteoblasts in a dose-dependent manner, and has a double-way effect on the osteoblasts in vitro. A low-dose showed positive effects on the development of osteoblasts, and high-dose puerarin could inhibit the formation of bone.
文摘Objective To observe the effects of two main isoflavones, daidzein and genistein on the bone-nodule formation in rat calvaria osteoblasts in vitro. Methods Osteoblasts obtained from newborn Sprague-dawley rat calvarias were cultured for several generations. The second generation cells were cultured in Minimum Essential Medium supplemented with ascorbic acid and Na-beta-glycerophosphate for several days, in the presence of daidzein and genistein, with or without the estrogen receptor antagonist ICI 182780. Number of nodules was counted at the end of the incubation period (day 20) by staining with Alizarin Red S calcium stain. The release of osteocalcin, as a marker of osteoblast activity, was also determined on day 7 and day 12 during the incubation period. Results Compared with the control, the numbers of nodules were both increased by incubation with daidzein and genistein. 17β-estradiol was used as a positive control and proved to be a more effective inducer of the increase in bone-nodules formation than daidzein and genistein. The release of osteocalcin into culture media was also increased in the presence of daidzein and genistein, as well as 17β-estradiol on day 7 and day 12 (day 12 were higher). The estrogen receptor antagonist ICI 182780 completely blocked the genistein- and 17β-estradiol-induced increase of nodule numbers and osteocalcin release in osteoblasts. However, the effects induced by daidzein could not be inhibited by ICI 182780. Conclusion These findings suggest that geinistein can stimulate bone-nodule formation and increase the release of osteocalcin in rat osteoblasts. The effects, like those induced by 17β-estradiol, are mediated by the estrogen receptor dependent pathway. Daidzein also can stimulate bone-nodule formation and increase the release of osteocalcin in rat osteoblasts, but it is not, at least not merely, mediated by the estrogen receptor dependent pathway.
基金supported by grants by NIH grant AR-044741(Y-PL) and R01DE023813 (Y-PL)
文摘INTRODUCTIONThe transforming growth factor-β （TGF-β） superfamily com- prises TGF-βs, Activin, bone morphogenetic proteins （BMPs） and other related proteins. TGF-β superfamily members act through a heteromeric receptor complex,, comprised of type I and type II receptors at the cell surface that transduce intracellular signals via Smad complex or mitogen-activated protein kinase （MAPK） cascade.
基金supported by the National Natural Science Foundation of China(No.81202865)
文摘There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy(HRT). The present study was designed to investigate the in vitro effects of estrogen-like activities of two widespread coumarins, osthole and imperatorin, using the MCF-7 cell proliferation assay and their alkaline phosphatase(ALP) activities in osteoblasts Saos-2 cells. The two compounds were found to strongly stimulate the proliferation of MCF-7 cells. The estrogen receptor-regulated ERα, progesterone receptor(PR) and PS2 m RNA levels were increased by treatment with osthole and imperatorin. All these effects were significantly inhibited by the specific estrogen receptor antagonist ICI182, 780. Cell cycle analysis revealed that their proliferation stimulatory effect was associated with a marked increase in the number of MCF-7 cells in S phase, which was similar to that observed with estradiol. It was also observed that they significantly increased ALP activity, which was reversed by ICI182,780. These results suggested that osthole and imperatorin could stimulate osteoblastic activity by displaying estrogenic properties or through the ER pathway. In conclusion, osthole and imperatorin may represent new pharmacological tools for the treatment of osteoporosis.
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.
文摘In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hi- erarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching （EE）. MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched （SEA） as well as Machined （M） surfaces respectively. The results show signifi- cant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.
基金supported by Shanghai Science and Technology R&D Fund(Grant No.0952nm04400)the National Natural Science Foundation of China(GrantNos.51071168and30973041)the Innovation Fund of SIC,CAS(Grant No.Y06ZC3130G)
文摘Silicon （Si） incorporated porous TiO2 coating （Si-TiO2） prepared on titanium （Ti） by micro-arc oxidation （MAO） technique was demonstrated to be cytocompatible in previous studies. In view of the potential clinical applications, a detailed in vitro study of the biological activity of Si-Ti02 coating, in terms of osteoblast （MC3T3-EI cells） morphology, proliferation, differentiation and mineralization was performed. Immunofluo- rescent staining indicated that cells seeded on the Si-TiO2 coating showed improved adhesion with developing mature cytoskeletons, which contained numerous distinct and well-defined actin stress fibers in the cell mem- branes compared with those on the Ti02 coating and Ti plate. Results from proliferation assay showed that the proliferation rate of cells seeded on the Si-TiO2coating was significantly faster than that on the TiO2 coating and Ti plate. Furthermore, the analysis of osteogenic gene expression demonstrated that the Si-Ti02 coating stimulated the expression of osteoblast-related genes and promoted differentiation and mineralization of MC3T3-EI cells. In addition, the Si-TiO2 coating differentially regulated Wnt signaling pathway by up-regulating the expression of low-density lipoprotein （LDL） receptor-related protein 5 （LrpS）, and downregulating the expression of Dickkopf-1 （Dkkl）. All together, these results indicate that the investigated titanium with Si-TiO2 coating is biocompatible and a good candidate material used as implants.
文摘Aim Given the well-known properties of Schwann cells in promoting nerve regeneration, transplanting Schwann cells into implant sockets might be an effective method to promote sensory responses of osseointegrated implants. The aim of this study was to evaluate the interaction between Schwann cells and osteoblasts. Methodology Schwann cells derived from the sciatic nerves of neonatal rat were co-culured with osteoblasts using Transwell inserts. The proliferation of Schwann cells in the co-culture system was evaluated using methylthiazol tetrazolium （MTT） colorimetric method. Moreover, the secretions and mRNA levels of brain-derived neurotrophic factor （BDNF） and nerve growth factor （NGF） were measured by enzyme-linked immunosorbent assay （ELISA） and quantitative real-time PCR, respectively. In order to test the effect of Schwann cells on osteoblasts, alkaline phosphatase （ALP） staining and Alizerin red staining were performed as well. Results Schwann cells, which were co-cultured with the osteoblasts, showed an intact proliferation during the observation period. Moreover, the gene expression and synthesis of BDNF and NGF were not impaired by the osteoblasts. Meanwhile, co-cultured osteoblasts exhibited a significant increase in the proliferation on day 3 and 6 （P〈 0.05）. Co-culture of these two types of cells also led to a more intense staining of ALP and an elevated number of calcified nodules. Conclusion These findings demonstrate that, in the in vitro indirect co-culture environment, Schwann cells can maintain their normal ability to synthesize neurotrophins, which then enhance the proliferation and differentiation of osteoblasts.
基金This work was supported by grants from the Int. Cooperation Project for National & Abroad Lab. of the National Natural Sciences Foundation of China (No. 2002008)The Science & Technology Foundation of Liaoning Province (No. 20022140).
文摘Objective To study large-scale expansion of SD （Sprague-Dawley） rat＇s osteoblasts in suspension culture in a rotating wall vessel bioreactor （RWVB）. Methods The bioreactor rotation speeds were adjusted in the range of 0 to 20 rpm, which could provide low shear on the rnicrocarriers around 1 dyn/cm^2. The cells were isolated via sequential digestions of neonatal （less than 3 days old） SD rat calvaria. After the primary culture and several passages, the cells were seeded onto the microcarriers and cultivated in T-flask, spinner flask and RWVB respectively. During the culture period, the cells were counted and observed under the inverted microscope for morphology every 12 h. After 7 days, the cells were evaluated with scanning electron microscope （SEM） for histological examination of the aggregates. Also, the hematoxylin-eosin （HE） staining and alkaline phosphatase （ALP） staining were performed. Moreover, von-Kossa staining and Alizarin Red S staining were carded out for mineralized nodule formation. Results The results showed that in RWVB, the cells could be expanded by more than ten times and they presented better morphology and vitality and stronger ability to form bones. Conclusions The developed RWVB can provide the culture environment with a relatively low shear force and necessary three-dimensional （3D） interactions among cells and is suitable for osteopath expansion in vitro.
基金supported by the National Natural Science Foundation (NNSF) Key Research Program in Aging (91749204)National Natural Science Foundation of China (81871099, 31370958, 81701364, 81771491, 81501052)+1 种基金Shanghai Municipal Science and Technology Commission Key Program (15411950600, 18431902300)Municipal Human Resources Development Program for Outstanding Leaders in Medical Disciplines in Shanghai (2017BR011)
文摘RANKL signaling is essential for osteoclastogenesis. Its role in osteoblastic differentiation and bone formation is unknown. Here we demonstrate that RANK is expressed at an early stage of bone marrow mesenchymal stem cells(BMSCs) during osteogenic differentiation in both mice and human and decreased rapidly. RANKL signaling inhibits osteogenesis by promoting β-catenin degradation and inhibiting its synthesis. In contrast, RANKL signaling has no significant effects on adipogenesis of BMSCs.Interestingly, conditional knockout of rank in BMSCs with Prx1-Cre mice leads to a higher bone mass and increased trabecular bone formation independent of osteoclasts. In addition, rank: Prx1-Cre mice show resistance to ovariectomy-(OVX) induced bone loss. Thus, our results reveal that RANKL signaling regulates both osteoclasts and osteoblasts by inhibition of osteogenic differentiation of BMSCs and promotion of osteoclastogenesis.
基金Project supported bythe National Natural Science Foundation of China (20031010 ,20271005)
文摘The effects of lanthanum （Ⅲ） on the bone resorbing activity of rabbit mature osteoclasts （OCs） in the presence of osteoblasts （OBs） were studied in vitro by measuring the number and area of absorption pits. La（ Ⅲ ） at concentrations ranging from 1.00 × 10^-5 to 1.00 × 10^-8 mol·L^-1 show no effect on mature OC number （P 〉 0.05）. In the OC-OB coculture systems without La（Ⅲ ）, osteoblasts alone did not influence the pit number and area whether the two kinds of cells were in contact or not （ P 〉 0.05）. Under the OC-OB not-in-contact condition, the effect of La（ Ⅲ ） on the bone-resorbing activity of OCs was similar to that of La（Ⅲ） in the absence of OBs （P 〉 0.05）. However, while OCs were in direct contact with OBs, the inhibitory effects of La（ Ⅲ ） on OCs＇ bone-resorbing activity decreased at the concentrations of 1.00 × 10^-5, 1.00×10^-6 and 1.00×10^-7mol·L^-1, and the promotion effects increased at 1.00×10^-8mol·L^-1 （P 〈0.05）. The results suggest that direct cell-cell contact between OC and OB be essential for OBs to play their role in regulating the response of OCs to La（ Ⅲ ）.
基金Fujian Provincial Natural Science:Exploration of Crisis Warning Values for Intraoperative Electrophysiological Monitoring in High-risk Cervical Spondylosis Patients on the Brink of Paralysis(No.2019J01548)Fujian Provincial Clinical Medical Research Center for First Aid and Rehabilitation in Orthopaedic Trauma:Study on the Treatment of Osteoporosis(No.2020Y2014)。
文摘OBJECTIVE:To explore the relationship between autophagy and apoptosis regulated by puerarin during osteoblastogenesis.METHODS:In this study,the effects of puerarin on the autophagic activity and apoptosis level of osteoblast precursors(MC3T3-E1 cells)was observed.Subsequently,the roles of puerarin on B-cell lymphoma-2(Bcl-2)phosphorylation at different sites in osteoblast precursors were observed.The effect of puerarin on the interaction between Bcl-2 and autophagy regulatory molecule or pro-apoptotic molecule was also investigated using Co-immunoprecipitation assays.In addition,the effect of puerarin on mitochondrial membrane potential of osteoblast precursors was also identified by mitochondrial membrane potential fluorescence probe assays.RESULTS:Our results showed that puerarin can promote the autophagic activity and apoptosis level of MC3T3-E1cells.In addition,puerarin promoted Bcl-2phosphorylation at Ser70 site,and the dissociation of Bcl-2-Beclin1 complex.Moreover,puerarin could enhance the binding of Bcl-2-Bcl-2-Associated X(Bax)complex in MC3T3-E1 cells.Furthermore,puerarin increased the mitochondrial membrane potential of MC3T3-E1 cells.CONCLUSIONS:Therefore,puerarin promotes Beclin1into autophagy flux through Bcl-2 phosphorylation at Ser70,thereby enhancing autophagy of osteoblast precursors,which mediates its anti-apoptotic role during osteoblastogenesis.Furthermore,the dissociation of Bcl-2-Beclin1 complex is conducive to the binding of Bcl-2-Bax complex,which resists the apoptosis of osteoblast precursors via the increased mitochondrial membrane potential.
文摘Summary: Rat transforming growth factor β1 (rTGFβ1) cDNA from rat lymphocytes was cloned by RT-PCR and inserted into pcDNA3 to construct an eukaryotic expression vector, which was named pcDNA3-TGFβ1. The cloned gene was confirmed to code rat TGFβ1 by restriction enzyme analysis. pcDNA3-TGFβ1 plasmid was transfected into rat osteoblasts by using liposome-mediated gene transfer technique and the expression of TGFβ1 was detected by using irnmunohistochemical staining assay. It was found that the rat TGFβ1 expression product was obviously detectable in the transfected osteoblasts in 48 h. High expression of TGFβ1 was obtained in the rat osteoblasts in which the constructed TGFβ1 expression vector was transfected.
