BACKGROUND: Congenital scoliosis (CS) is a complex spinal malformation of unknown etiology with abnormal bone metabolism. Fibroblast growth factor 23 (FGF23), secreted by osteoblasts and osteocytes, can inhibit bone formation and mineralization. This research aims to investigate the relationship between CS and FGF23. METHODS: We collected peripheral blood from two pairs of identical twins for methylation sequencing of the target region. FGF23 mRNA levels in the peripheral blood of CS patients and age-matched controls were measured. Receiver operator characteristic (ROC) curve analyses were conducted to evaluate the specificity and sensitivity of FGF23. The expression levels of FGF23 and its downstream factors fibroblast growth factor receptor 3 (FGFr3)/tissue non-specific alkaline phosphatase (TNAP)/osteopontin (OPN) in primary osteoblasts from CS patients (CS-Ob) and controls (CT-Ob) were detected. In addition, the osteogenic abilities of FGF23-knockdown or FGF23-overexpressing Ob were examined. RESULTS: DNA methylation of the FGF23 gene in CS patients was decreased compared to that of their identical twins, accompanied by increased mRNA levels. CS patients had increased peripheral blood FGF23 mRNA levels and decreased computed tomography (CT) values compared with controls. The FGF23 mRNA levels were negatively correlated with the CT value of the spine, and ROCs of FGF23 mRNA levels showed high sensitivity and specificity for CS. Additionally, significantly increased levels of FGF23, FGFr3, OPN, impaired osteogenic mineralization and lower TNAP levels were observed in CS-Ob. Moreover, FGF23 overexpression in CT-Ob increased FGFr3 and OPN levels and decreased TNAP levels, while FGF23 knockdown induced downregulation of FGFr3 and OPN but upregulation of TNAP in CS-Ob. Mineralization of CS-Ob was rescued after FGF23 knockdown. CONCLUSIONS Our results suggested increased peripheral blood FGF23 levels, decreased bone mineral density in CS patients, and a good predictive ability of CS by peripheral blood FGF23 levels. FGF23 may contribute to osteopenia in CS patients through FGFr3/TNAP / OPN pathway.
Humans ; Osteopontin/genetics* ; Alkaline Phosphatase/metabolism* ; Receptor, Fibroblast Growth Factor, Type 3/metabolism* ; Scoliosis/genetics* ; Osteoblasts/metabolism* ; Calcinosis ; RNA, Messenger/metabolism* ; Bone Diseases, Metabolic/metabolism* ; Fibroblast Growth Factors/genetics*

OBJECTIVE: High glucose (HG) can influence the osteogenic differentiation ability of periodontal ligament stem cells (PDLSCs). Human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-exo) have broad application prospects in tissue healing. The current study aimed to explore whether hUCMSC-exo could promote the osteogenic differentiation of hPDLSCs under HG conditions and the underlying mechanism. METHODS: We used a 30 mmol/L glucose concentration to simulate HG conditions. CCK-8 assay was performed to evaluate the effect of hUCMSC-exo on the proliferation of hPDLSCs. Alkaline phosphatase (ALP) staining, ALP activity, and qRT-PCR were performed to evaluate the pro-osteogenic effect of hUCMSC-exo on hPDLSCs. Western blot analysis was conducted to evaluate the underlying mechanism. RESULTS: The results of the CCK-8 assay, ALP staining, ALP activity, and qRT-PCR assay showed that hUCMSC-exo significantly promoted cell proliferation and osteogenic differentiation in a dose-dependent manner. The Western blot results revealed that hUCMSC-exo significantly increased the levels of p-PI3K and p-AKT in cells, and the effect was inhibited by LY294002 (PI3K inhibitor) or MK2206 (AKT inhibitor), respectively. Moreover, the increases in osteogenic indicators induced by hUCMSC-exo were significantly suppressed by LY294002 and MK2206. CONCLUSION hUCMSC-exo promote the osteogenic differentiation of hPDLSCs under HG conditions through the PI3K/AKT signaling pathway.
Alkaline Phosphatase ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Exosomes/metabolism* ; Glucose/pharmacology* ; Humans ; Mesenchymal Stem Cells/metabolism* ; Osteogenesis ; Periodontal Ligament/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Signal Transduction ; Sincalide/pharmacology* ; Stem Cells/metabolism* ; Umbilical Cord/metabolism*

It is known that low-frequency pulsed electromagnetic fields (PEMFs) can promote the differentiation and maturation of rat calvarial osteoblasts (ROBs) cultured in vitro. However, the mechanism that how ROBs perceive the physical signals of PEMFs and initiate osteogenic differentiation remains unknown. In this study, we investigated the relationship between the promotion of osteogenic differentiation of ROBs by 0.6 mT 50 Hz PEMFs and the presence of polycystin2 (PC2) located on the primary cilia on the surface of ROBs. First, immunofluorescence staining was used to study whether PC2 is located in the primary cilia of ROBs, and then the changes of PC2 protein expression in ROBs upon treatment with PEMFs for different time were detected by Western blotting. Subsequently, we detected the expression of PC2 protein by Western blotting and the effect of PEMFs on the activity of alkaline phosphatase (ALP), as well as the expression of Runx-2, Bmp-2, Col-1 and Osx proteins and genes related to bone formation after pretreating ROBs with amiloride HCl (AMI), a PC2 blocker. Moreover, we detected the expression of genes related to bone formation after inhibiting the expression of PC2 in ROBs using RNA interference. The results showed that PC2 was localized on the primary cilia of ROBs, and PEMFs treatment increased the expression of PC2 protein. When PC2 was blocked by AMI, PEMFs could no longer increase PC2 protein expression and ALP activity, and the promotion effect of PEMFs on osteogenic related protein and gene expression was also offset. After inhibiting the expression of PC2 using RNA interference, PEMFs can no longer increase the expression of genes related to bone formation. The results showed that PC2, located on the surface of primary cilia of osteoblasts, plays an indispensable role in perceiving and transmitting the physical signals from PEMFs, and the promotion of osteogenic differentiation of ROBs by PEMFs depends on the existence of PC2. This study may help to elucidate the mechanism underlying the promotion of bone formation and osteoporosis treatment in low-frequency PEMFs.
Alkaline Phosphatase/metabolism* ; Animals ; Electromagnetic Fields ; Osteoblasts/metabolism* ; Osteogenesis/genetics* ; Rats ; TRPP Cation Channels/physiology*

OBJECTIVE: To explore effect of tobramycin (TOB) on healing of femoral fractures in rats. METHODS: Totally 32 male sprague-dawley (SD) rats were selected and randomly divided into sham group (group A), fracture group (group B), fracture with TOB group (group C) and fracture + TOB + IWR-1 group (group D), 8 rats in each group. Close femoral fracture model in rats were established in group B, C and D, group A was sham operation without otherwise process. Group D was intraperitoneal injected 100 μl (8 μM) of Wnt pathway inhibitor IWR-1-endo (IWR-1) before molding at 1 day. At 1 day after molding, 100 μl (100 μM) of TOB was intraperitoneally injected into group C and D at once a day for 7 days. At 7 weeks after modling, fracture healing of group B, C and D were observed by X-ray, Western blotting was appilied to detect alkaline phosphatase(ALP) and Runt related transcription factor 2 (RUNX2) and β-catenin of Wnt passway. RESULTS: X-ray results showed fracture line disappeared, callus formation and fracture healing well in group C compared with begning of molding; while a little fracture line, callus formation and fracture malunion in group B and d could be seen. Western blotting results showed ALP, RUNX2 and expression of β-catenin in group B, C and D were higher than that of group A ( CONCLUSION Tobramycin could promote osteoblast differentiation and fracture healing by stimulating Wnt / β-catenin signaling pathway, up regulating expression of ALP and RUNX2.
Alkaline Phosphatase ; Animals ; Cell Differentiation ; Core Binding Factor Alpha 1 Subunit/genetics* ; Femoral Fractures ; Fracture Healing ; Male ; Osteogenesis ; Rats ; Tobramycin ; Wnt Signaling Pathway ; beta Catenin/metabolism*

PURPOSE: Bone plays a role in glucose metabolism through the release of uncarboxylated osteocalcin into the systemic circulation. The identified novel roles for osteocalcin include increasing insulin secretion and sensitivity, energy expenditure, reduction of fat mass, and mitochondrial proliferation and functional enhancement. This study aimed to determine serum osteocalcin levels in overweight children and to investigate the relationships of osteocalcin with glucose metabolism and insulin sensitivity. METHODS: After overnight fasting, serum osteocalcin levels were measured in overweight (n=50) children between 6.0 and 12.9 years of age and nonoverweight controls (n=60). Height, weight, fasting serum glucose, insulin, alkaline phosphatase, total cholesterol, and 25 hydroxy vitamin D₃ (25(OH)VitD₃) were also measured in all subjects. RESULTS: There were significant differences in serum osteocalcin levels between the overweight and control groups (64.00±20.44 vs. 89.56±28.63, P<0.001). Serum osteocalcin levels were inversely correlated with body mass index (BMI) (r=-0.283, P=0.003), weight standard deviation score (SDS) (r=-0.222, P=0.020), BMI SDS (r=-0.297, P=0.002), insulin (r=-0.313, P=0.001), and homeostasis model assessment of insulin resistance (HOMA-IR) index (r=-0.268, P=0.005). In the subsequent multiple regression analyses, BMI, HOMA-IR, and age were determined to be independent predicting factors for serum osteocalcin. CONCLUSIONS: Our findings showed associations of serum osteocalcin with glucose metabolism and insulin sensitivity in overweight children, but we could not establish a causal relationship.
Alkaline Phosphatase ; Blood Glucose ; Body Mass Index ; Child ; Cholesterol ; Energy Metabolism ; Fasting ; Glucose ; Homeostasis ; Humans ; Insulin ; Insulin Resistance ; Metabolism ; Osteocalcin ; Overweight ; Vitamins

Skeletal mineralization is initiated in matrix vesicles (MVs), the small extracellular vesicles derived from osteoblasts and chondrocytes. Calcium and inorganic phosphate (Pi) taken up by MVs form hydroxyapatite crystals, which propagate on collagen fibrils to mineralize the extracellular matrix. Insufficient calcium or phosphate impairs skeletal mineralization. Because active vitamin D is necessary for intestinal calcium absorption, vitamin D deficiency is a significant cause of rickets/osteomalacia. Chronic hypophosphatemia also results in rickets/osteomalacia. Excessive action of fibroblast growth factor 23 (FGF23), a key regulator of Pi metabolism, leads to renal Pi wasting and impairs vitamin D activation. X-linked hypophosphatemic rickets (XLH) is the most common form of hereditary FGF23-related hypophosphatemia, and enhanced FGF receptor (FGFR) signaling in osteocytes may be involved in the pathogenesis of this disease. Increased extracellular Pi triggers signal transduction via FGFR to regulate gene expression, implying a close relationship between Pi metabolism and FGFR. An anti-FGF23 antibody, burosumab, has recently been developed as a new treatment for XLH. In addition to various forms of rickets/osteomalacia, hypophosphatasia (HPP) is characterized by impaired skeletal mineralization. HPP is caused by inactivating mutations in tissue-nonspecific alkaline phosphatase, an enzyme rich in MVs. The recent development of enzyme replacement therapy using bone-targeting recombinant alkaline phosphatase has improved the prognosis, motor function, and quality of life in patients with HPP. This links impaired skeletal mineralization with various conditions, and unraveling its pathogenesis will lead to more precise diagnoses and effective treatments.
Absorption ; Alkaline Phosphatase ; Calcium ; Chondrocytes ; Collagen ; Diagnosis ; Durapatite ; Enzyme Replacement Therapy ; Extracellular Matrix ; Extracellular Vesicles ; Familial Hypophosphatemic Rickets ; Fibroblast Growth Factors ; Gene Expression ; Humans ; Hypophosphatasia ; Hypophosphatemia ; Metabolism ; Miners ; Osteoblasts ; Osteocytes ; Prognosis ; Quality of Life ; Receptors, Fibroblast Growth Factor ; Rickets ; Signal Transduction ; Vitamin D ; Vitamin D Deficiency

Alkaline Phosphatase ; metabolism ; Asian Continental Ancestry Group ; Bone Density Conservation Agents ; therapeutic use ; China ; Denosumab ; therapeutic use ; Diabetes Mellitus, Type 2 ; complications ; Female ; Humans ; Hyperlipidemias ; complications ; Hypertension ; complications ; Middle Aged ; Osteitis Deformans ; complications ; diagnostic imaging ; drug therapy ; metabolism ; Pelvic Bones ; diagnostic imaging ; Renal Insufficiency, Chronic ; complications ; Singapore ; Tibia ; diagnostic imaging ; Treatment Outcome

Bone formation is important for the reconstruction of bone-related structures in areas that have been damaged by inflammation. Inflammatory conditions such as those that occur in patients with rheumatoid arthritis, cystic fibrosis, and periodontitis have been shown to inhibit osteoblastic differentiation. This study focussed on dental follicle stem cells (DFSCs), which are found in developing tooth germ and participate in the reconstruction of alveolar bone and periodontal tissue in periodontal disease. After bacterial infection of inflamed dental tissue, the destruction of bone was observed. Currently, little is known about the relationship between the inflammatory environment and bone formation. Osteogenic differentiation of inflamed DFSCs resulted in decreased alkaline phosphatase (ALP) activity and alizarin red S staining compared to normal DFSCs. Additionally, in vivo transplantation of inflamed and normal DFSCs demonstrated severe impairment of osteogenesis by inflamed DFSCs. Protein profile analysis via liquid chromatography coupled with tandem mass spectrometry was performed to analyse the differences in protein expression in inflamed and normal tissue. Comparison of inflamed and normal DFSCs showed significant changes in the level of expression of transforming growth factor (TGF)-β2. Porphyromonas gingivalis (P.g.)-derived lipopolysaccharide (LPS) was used to create in vitro inflammatory conditions similar to periodontitis. The osteogenic differentiation of LPS-treated DFSCs was suppressed, and the cells displayed low levels of TGF-β1 and high levels of TGF-β2. DFSCs treated with TGF-β2 inhibitors showed significant increases in alizarin red S staining and ALP activity. TGF-β1 expression was also increased after inhibition of TGF-β2. By examining inflamed DFSCs and LPS-triggered DFSCs, these studies showed both clinically and experimentally that the increase in TGF-β2 levels that occurs under inflammatory conditions inhibits bone formation.
Adolescent ; Alkaline Phosphatase ; metabolism ; Animals ; Cell Differentiation ; Cell Proliferation ; Cell Survival ; Cells, Cultured ; Dental Sac ; cytology ; metabolism ; Down-Regulation ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Immunohistochemistry ; Male ; Mass Spectrometry ; Mice ; Nitric Oxide ; metabolism ; Osteogenesis ; drug effects ; Polymerase Chain Reaction ; Staining and Labeling ; Stem Cells ; cytology ; metabolism ; Transforming Growth Factor beta2 ; pharmacology ; Young Adult

Amelogenin (AMG) is a cell adhesion molecule that has an important role in the mineralization of enamel and regulates events during dental development and root formation. The purpose of the present study was to investigate the effects of recombinant human AMG (rhAMG) on mineralized tissue-associated genes in cementoblasts. Immortalized mouse cementoblasts (OCCM-30) were treated with different concentrations (0.1, 1, 10, 100, 1000, 10,000, 100,000 ng · mL) of recombinant human AMG (rhAMG) and analyzed for proliferation, mineralization and mRNA expression of bone sialoprotein (BSP), osteocalcin (OCN), collagen type I (COL I), osteopontin (OPN), runt-related transcription factor 2 (Runx2), cementum attachment protein (CAP), and alkaline phosphatase (ALP) genes using quantitative RT-PCR. The dose response of rhAMG was evaluated using a real-time cell analyzer. Total RNA was isolated on day 3, and cell mineralization was assessed using von Kossa staining on day 8. COL I, OPN and lysosomal-associated membrane protein-1 (LAMP-1), which is a cell surface binding site for amelogenin, were evaluated using immunocytochemistry. F-actin bundles were imaged using confocal microscopy. rhAMG at a concentration of 100,000 ng · mL increased cell proliferation after 72 h compared to the other concentrations and the untreated control group. rhAMG (100,000 ng · mL) upregulated BSP and OCN mRNA expression levels eightfold and fivefold, respectively. rhAMG at a concentration of 100,000 ng · mL remarkably enhanced LAMP-1 staining in cementoblasts. Increased numbers of mineralized nodules were observed at concentrations of 10,000 and 100,000 ng · mL rhAMG. The present data suggest that rhAMG is a potent regulator of gene expression in cementoblasts and support the potential application of rhAMG in therapies aimed at fast regeneration of damaged periodontal tissue.
Alkaline Phosphatase ; metabolism ; Amelogenin ; physiology ; Animals ; Biomarkers ; metabolism ; Calcification, Physiologic ; Cell Adhesion Molecules ; metabolism ; Cell Proliferation ; Cementogenesis ; physiology ; Collagen Type I ; metabolism ; Core Binding Factor Alpha 1 Subunit ; metabolism ; Gene Expression Regulation ; In Vitro Techniques ; Integrin-Binding Sialoprotein ; metabolism ; Mice ; Microscopy, Confocal ; Osteocalcin ; metabolism ; Osteopontin ; metabolism ; Real-Time Polymerase Chain Reaction

OBJECTIVE: This study aims to investigate the effect of neurotrophin 3 (NT-3) on the osteogenic differentiation of human dental follicle cells (hDFCs). METHODS: hDFCs were isolated and cultured in vitro. Immunocytochemical staining was used to identify the origin of hDFCs. The effects of different NT-3 concentrations on hDFCs proliferation were detected by using CCK-8 assay. The alkaline phosphatase (ALP) activities and mRNA expression levels of bone morphogenetic protein-2 (BMP-2) and osteocalcin (OCN) were determined to investigate the effects of NT-3 on hDFCs osteogenesis. The difference in the number of mineralized nodules was detected using alizarin red staining. RESULTS: Vimentin and cytokeratin staining results showed that hDFCs originated from the mesenchymal cells. NT-3 exerted no evident effect on hDFCs proliferation. The ALP activity and the BMP-2 and OCN mRNA expression levels of hDFCs were significantly improved under treatment with different NT-3 concentrations (25, 50, and 100 ng·mL ⁻¹) compared with those in the control group. BMP-2 and OCN mRNA relative expression levels of hDFCs reached the highest when the NT-3 concentration was 100 ng·mL ⁻¹. The number of mineralized nodules reached the maximum when the hDFCs were treated with 50 and 100 ng·mL ⁻¹ NT-3. CONCLUSIONS Appropriate mass concentration of NT-3 can promote the osteogenic differentiation of hDFCs.
Alkaline Phosphatase ; Bone Morphogenetic Protein 2 ; metabolism ; Cell Differentiation ; Cells, Cultured ; Dental Sac ; Humans ; Mesenchymal Stem Cells ; Neurotrophin 3 ; pharmacology ; Osteocalcin ; metabolism ; Osteogenesis