ABSTRACT
Objective To explore the effect and mechanism of magnesium on calcification induced by hyperphosphate.Methods Vascular smooth muscle cells (VSMCs) were primarily cultured in vitro and induced calcification by β-glycerophosphate (β-GP).VSMCs were randomly divided into control group,high phosphorus group (10 mmol/L β-GP),magnesium intervèntion group(10 mmol/L β-GP + 3 mmol/L MgSO4) and 2-aminoethoxy-diphenylborate (2-APB,an inhibitor of magnesium transporter) intervention group(10 mmol/L β-GP+3 mmol/L MgSO4+ 10-4 mol/L 2-APB).Calcium deposition and alkaline phosphatase (ALP) activity were measured by alizarin red staining,quantification of calcium and euzyme linked immunosorbent assay.RT-PCR and Western blotting were used to observe the expression of core binding factor α-1 (Cbfα-1) mRNA and protein,respectively.In vivo,male Sprague-Dawley rats (n=24) were randomly divided into control group (methylcellulose+high phosphorous diet),vascular calcification group (adenine suspension + high phosphorous diet),high magnesium intervention group(adenine suspension+high phosphorous and magnesium diet).The aortic pulse wave velocity (PWV) was measured,and vascular calcification was determined by von Kossa stain and quantification of calcium.Cbfα-1 in aortic was measured by immunohistochemistry.Results In vitro,compared with high phosphorus group,calcification,ALP activity (P ＜ 0.05) and Cbfα-1expression in VSMCs were significantly decreased in magnesium intervention group after incubation for 14 days,but the addition of 2-APB might inhibit the protective effect of magnesium on VSMCs.Dynamic observation of Cbfα-1 showed that magnesium significantly inhibited the expression of Cbfα-1 (P ＜ 0.05) on the third day and the inhibitory role was obviously increased in a time-dependent manner.Consistent with the findings in vitro,the aortic PWV,calcification were all significantly reduced (P ＜ 0.05) in high magnesium intervention group with high serum magnesium level,when compared with vascular calcification group.Immunohistochemistry showed that hypermagnesemia downregulated obviously the expression of Cbfα-1 induced by hyperphosphatemia(P ＜ 0.05).Conclusion Magnesium protects against vascular calcification by inhibiting osteogenic differentiation of VSMCs.
ABSTRACT
BACKGROUND:Unlike the ilium derived from the paraxial mesoderm, the mandible from cranial neural crest has a unique mechanism. Core binding factorα1 (Cbfα1) is a key transcription factor for skeletogenic process. However, the role of Cbfα1/p56 subtype in mandible tissue is yet not clear. OBJECTIVE:To research the expression of Cbfα1/p56 subtype in bone marrow mesenchymal cells from rat mandible in vitro. METHODS:Bone marrow mesenchymal stem cells from rat mandible and ilium were in vitro isolated and purified by primary culture. The characteristics of bone marrow mesenchymal cells were compared through the methods of enzyme linked immunosorbent assay and real-time PCR, including growth curve, alkaline phosphatase activity and relative mRNA expression of Cbfα1 subtypes. RESULTS AND CONCLUSION:Bone marrow mesenchymal cells from rat mandible and ilium were successful y obtained. Bone marrow mesenchymal cells from the mandible proliferated more rapidly, alkaline phosphatase activity of which was higher than iliac cells. The relative mRNA expression of Cbfα1/p56 subtype in bone marrow mesenchymal cells from the mandible was more than that in iliac cells at 6 days of culture (P0.05). The results showed that Cbfα1/p56 is very significant in the early osteogenic differentiation of bone marrow mesenchymal cells from the mandible.
ABSTRACT
BACKGROUND:Runx2 is considered to the main regulatory factor of osteogenic gene expression and be necessary for osteoblast differentiation, it plays an extremely important role in the osteoblast development, differentiation, regulation, bone calcification formation and bone repair. OBJECTIVE:To observe the biological properties of mesenchymal stem cells from human exfoliated deciduous teeth, explore the osteogenic differentiation potential of deciduous teeth stem cells, and observe the dynamic expression of Runx2 gene at varying time points. METHODS:The stem cells from human exfoliated deciduous teeth were isolated and cultured in vitro. The cellsurface antigen was detected with flow cytometry. The third passage cells were cultured in the adipogenic medium for 4 weeks, and oil red O staining was conducted to test lipid droplets formation. The third passage cells were cultured in the osteogenic medium for 21 days, and mineralized nodules were detected by alizarin red staining. Runx2 mRNA dynamic expression was detected with semi-quantitative RT-PCR at different time points. RESULTS AND CONCLUSION:The stem cells from human exfoliated deciduous teeth were obtained by enzyme digestion and limited dilution methods. Flow cytometry results showed that, CD146 and STRO-1 were expressed to varying degrees. Oil red O staining revealed salmon pink positive particles. Alizarin red staining showed positive expression. RT-PCR results showed that, Runx2 expression was found at day 0, up-regulated from day 0 to day 6, and subsequently dropped with an expression bottom at day 12, after that a second expression peak occurred at day 18, fol owed by a stably regulation. The stem cells from human exfoliated deciduous teeth can be isolated and cultured in vitro, express surface antigen of mesenchymal stem cells, and have the potentials of differentiating into adipocytes and ostetoblasts. Runx2 gene profiles are dynamical y expressed during osteoblastic differentiation. Runx2 express throughout every stage of osteoblastic differentiation. The expression is up-regulated during early and later stages, and down-regulated in metaphase.
ABSTRACT
Objective To explore the effects of the different concentrations of magnesium ions on vascular smooth muscle cell (VSMC) calcification in rats. Methods VSMCs were obtained from rat aortic, and were identified by immunocy-tochemistry. VSMCs were then randomly divided into control group, high phosphorus group and magnesium intervention group. VSMCs were cultured with 10%fetal bovine serum in control group. VSMCs were cultured with high phosphorus in high phosphorus group. VSMCs were cultured with different concentrations of magnesium chloride based on the high phos-phorus medium in magnesium intervention group (final concentrations of magnesium ions were 1, 2 and 3 mmol/L). The calci-um content and alkaline phosphatase(ALP)activity were measured after the stimulation for 7 days. The expression of Cbfα1 mRNA was detected by RT-PCR. Results Compared with control group, calcium deposits were found significantly higher in high phosphorus group and magnesium intervention group. The calcified nodules gradually reduced with the increased magnesium ion concentration in the intervention group. The calcium contents were significantly lower in the intervention groups (2 and 3 mmol/L) compared with those of high phosphorus group (P<0.05), but no difference was found between 1 mmol/L magnesium intervention group and high phosphorus group. There were no significant differences in the ALP activity and Cbfα1 mRNA expression between intervention groups (2 and 3 mmol/L) and control group (P<0.05). The ALP activity and the expression of Cbfα1 mRNA were gradually decreased with the increased magnesium ion concentration in the inter-vention group, and which were lower than those of high phosphorus group (P<0.05). Conclusion Magnesium can reduce calcification and osteoblastic transdifferentiation, which may be achieved by reducing the expression of Cbfα1 in VSMCs.
ABSTRACT
BACKGROUND: Chinese medicine Gukang prescription has a clear effect on clinical treatment of osteoporosis, but the therapeutic pathway is stil unclear. OBJECTIVE:To investigate the effects of Chinese medicine Gukang on the expression of receptor activator of nuclear factor kappa B ligand and osteoprotegerin by regulating core binding factor alpha 1 expression to control the growth and development of osteoblasts. METHODS:Sprague-Dawley neonatal rats within 24 hours after delivery were used for the separation and culture of osteoblasts. Adult Sprague-Dawley rats were used to prepare drug-containing serum, and then divided into two groups randomly:normal control group and Gukang group. Rats in the normal control and Gukang groups were intragastrical y administrated with extract of Gukang prescription and normal saline based on rat’s body surface area, for 1 consecutive week. Two hours after the last administration, blood samples were taken from the heart. Then the serum was col ected. Osteoblasts at passage 3 were confirmed with alkaline phosphatase assay and digested. After counting and planting, al osteoblasts were divided into two groups and treated with col ected serum for 72 hours. Proliferative rate of osteoblasts was detected by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test. Secretion of alkaline phosphatase was detected by using enzyme linked immunosorbent assay and corrected with the corresponding absorbance value. mRNA expression of core binding factor alpha 1, receptor activator of nuclear factor kappa B ligand and osteoprotegerin were detected by using reverse transcription-PCR in al groups. RESULTS AND CONCLUSION:mRNA expression of osteoprotegerin and core binding factor alpha 1 in the Gukang group was significantly higher than that in the normal control group, but protein and mRNA expression of receptor activator of nuclear factor kappa B ligand were dramatical y lower in the Gukang group compared with the normal control group (Pcore binding factor alpha 1, thereby adjusting the expression of receptor activator of nuclear factor kappa B ligand and osteoprotegerin, which may be one of the mechanisms underlying Gukang treatment for osteoporosis.
ABSTRACT
Objective To study the relationship between the medial artery calcification and expression of core-binding factor alpha 1 (Cbf α-1) and collagen Ⅱ (Col Ⅱ) in chronic kidney disease (CKD) stage 5 patients.Methods Pieces of radial arteries were taken from 40 patients with CKD stage 5 during internal arteriovenous fistula operation.Ten patients with subtotal gastrectomy and normal renal function were chosen as control.The vessels were examined for calcification by von Kossa stain and for the presence of Cbfα-1 and Col Ⅱ by immunohistochemistry.According to von Kossa stain,CKD stage 5 patients were divided into no calcification group,mild-moderate calcification group and severe calcification group.Other related factors including serum calcium,phosphate,intact parathyroid hormone (iPTH),C-reactive protein (CRP),triglyceride(TG),cholesterol(TC) and lowdensity lipoproteins(LDL) were also detected.Results Seventeen (42.5％) of CKD Stage 5 patients showed vascular calcification,while calcification was not found in controls.Most calcification occurred in medial layer.Positive immunohistochemical staining of core-binding factor and Col Ⅱ was found in the smooth muscular cell plasma of medial layer in the vessels with calcification.However,above positive staining was also observed in 78.3％ of no calcification group.But there was little staining in control group.Positive staining score of Cbfα-1 and Col Ⅱ in severe calcification group was significantly higher than that in no calcification group.Same findings were obtained in mild-moderate calcification group,but the difference between them was not statistically significant.CRP and Ca × P were positively correlated with staining score of Cbfα-1 and Col Ⅱ.Serum phosphate was positively correlated with Cbfα-1 (r=0.786,P＜0.01) and Col Ⅱ (r=0.785,P＜0.01) respectively.Conclusions 42.5％ of CKD stage 5 patients in our group shows vascular calcification,which occurrs mainly in medial layer.High expression of Cbfα-1 and Col Ⅱ can be observed in vascular calcification of radial arteries,which is earlier than vascular histological changes.Cbfα-1 and Col Ⅱ may be involved in the development of vascular calcification.
ABSTRACT
OBJECTIVE To investigate the effect of tacrolimus on cell proliferation and osteoblastic differentiation of primary human bone marrow-derived mesenchymal stem cells (hBMSCs). METHODS hBMSCs were cultured with tacrolimus 0.001-5 μmol·L-1. BrdU incorporation was used to assess the cell proliferation while cellular alkaline phosphatase (ALP) activity and calcium deposition were measured to evaluate the osteoblastic differentiation of hBMSCs cultures. The calcineurin (CaN) activity was also examined using commercial CaN assay kit, and core binding factor 1 alpha subunit (Cbfα1) protein level was determined by Western blotting. RESULTSTacrolimus 0.001-0.1 μmol·L-1 promoted BrdU incorporation but had no effect on ALP activity and calcium deposition, whereas tacrolimus 0.5-5 μmol·L-1 resulted in significant decrease in both cell proliferation and osteoblastic maturation, by reducing BrdU incorporation, ALP activity, and calcium deposition of hBMSCs cultures in a concentration-dependent manner. In addition, tacrolimus 0.5-5 μmol·L-1 led to concentration-dependent decrement in CaN activity, which was consistent with down-regulated Cbfα1 protein in the tacrolimus treated cells. CONCLUSION High concentration of tacrolimus might inhibit the cell proliferation and osteoblastic differentiation of hBMSCs cultures through a CaN/Cbfα1 pathway.
ABSTRACT
OBJETIVOS: A proposta deste estudo foi avaliar a expressão de proteínas que participam da fase de osteoindução (VEGF, BMP-2 e CBFA1) durante o processo de regeneração óssea de defeitos criados em calvária de ratos e preenchidos com enxerto autógeno em bloco. MATERIAIS E MÉTODOS: Para o presente estudo foram utilizados 10 ratos adultos machos (Rattus norvegicus albinus, Wistar) que receberam dois defeitos ósseos de 5 mm cada, em calvária. Os defeitos ósseos constituiram dois grupos experimentais (n=10): Grupo controle (CONT) (defeitos preenchidos com o próprio coágulo); Grupo enxerto (ENX) (defeitos preenchidos com osso autógeno removido do defeito contralateral). Os animais foram submetidos a eutanásia nos períodos de 7 e 30 dias pós-operatórios. RESULTADOS: A análise quantitativa demonstrou formação óssea significativamente maior no Grupo ENX, no entanto, a presença das proteínas estudadas foi significativamente maior no Grupo CONT em ambos os períodos de observação. CONCLUSÃO: O enxerto ósseo autógeno cortical em bloco não expressou de forma significativa as proteínas osteoindutoras estudadas durante o processo de reparo
AIMS: The proposal of this study was to evaluate the expression of proteins that act in osteoinduction (VEGF, BMP-2, CBFA1) phase during the bone defects regeneration created in rat calvaria and filled with autogenous bone graft in block. METHODS: For the present study, 10 adult male rats (Rattus norvegicus albinus, Wistar) had two 5mm- bone defects in calvaria. Bone defects constituted two experimental groups: CONTROL Group (defects filled with blood clot); GRAFT Group (defects filled with bone graft). Animals were sacrificed at 7 and 30 days post operative. RESULTS: Quantitative analysis showed significantly higher bone formation in Graft Group, however, the presence of studied proteins was significantly higher in Control Group in both observation periods. CONCLUSION: Autogenous cortical bone graft in block did not express the studied osteoinductive proteins during bone repair
Subject(s)
Animals , Rats , Bone Regeneration , Bone Transplantation , Core Binding Factor Alpha 1 Subunit , Vascular Endothelial Growth Factor A , ImmunohistochemistryABSTRACT
OBJETIVOS: A proposta deste estudo foi avaliar a expressão de proteínas que participam da fase de osteoindução (VEGF, BMP-2 e CBFA1) durante o processo de regeneração óssea de defeitos criados em calvária de ratos e preenchidos com enxerto autógeno em bloco. MATERIAIS E MÉTODOS: Para o presente estudo foram utilizados 10 ratos adultos machos (Rattus norvegicus albinus, Wistar) que receberam dois defeitos ósseos de 5 mm cada, em calvária. Os defeitos ósseos constituiram dois grupos experimentais (n=10): Grupo controle (CONT) (defeitos preenchidos com o próprio coágulo); Grupo enxerto (ENX) (defeitos preenchidos com osso autógeno removido do defeito contralateral). Os animais foram submetidos a eutanásia nos períodos de 7 e 30 dias pós-operatórios. RESULTADOS: A análise quantitativa demonstrou formação óssea significativamente maior no Grupo ENX, no entanto, a presença das proteínas estudadas foi significativamente maior no Grupo CONT em ambos os períodos de observação. CONCLUSÃO: O enxerto ósseo autógeno cortical em bloco não expressou de forma significativa as proteínas osteoindutoras estudadas durante o processo de reparo
AIMS: The proposal of this study was to evaluate the expression of proteins that act in osteoinduction (VEGF, BMP-2, CBFA1) phase during the bone defects regeneration created in rat calvaria and filled with autogenous bone graft in block. METHODS: For the present study, 10 adult male rats (Rattus norvegicus albinus, Wistar) had two 5mm- bone defects in calvaria. Bone defects constituted two experimental groups: CONTROL Group (defects filled with blood clot); GRAFT Group (defects filled with bone graft). Animals were sacrificed at 7 and 30 days post operative. RESULTS: Quantitative analysis showed significantly higher bone formation in Graft Group, however, the presence of studied proteins was significantly higher in Control Group in both observation periods. CONCLUSION: Autogenous cortical bone graft in block did not express the studied osteoinductive proteins during bone repair
Subject(s)
Animals , Rats , Bone Regeneration , Bone Transplantation , Core Binding Factor Alpha 1 Subunit , Vascular Endothelial Growth Factor A , ImmunohistochemistryABSTRACT
PURPOSE: Bone tissues for clinical application can be improved by studies on osteoblast differentiation. Runx2 is known to be an important transcription factor for osteoblast differentiation. However, bone morphogenetic protein (BMP)-2 treatment to stimulate Runx2 is not sufficient to acquire enough bone formation in osteoblasts. Therefore, it is necessary to find other regulatory factors which can improve the transcriptional activity of Runx2. The erythroblast transformation-specific (ETS) transcription factor family is reported to be involved in various aspects of cellular proliferation and differentiation. METHODS: We have noticed that the promoters of osteoblast differentiation markers such as alkaline phosphatase (Alp), osteopontin (Opn), and osteocalcin (Oc) contain Ets binding sequences which are also close to Runx2 binding elements. Luciferase assays were performed to measure the promoter activities of these osteoblast differentiation markers after the transfection of Runx2, myeloid Elf-1-like factor (MEF), and Runxs+MEF. Reverse-transcription polymerase chain reaction was also done to check the mRNA levels of Opn after Runx2 and MEF transfection into rat osteoblast (ROS) cells. RESULTS: We have found that MEF, an Ets transcription factor, increased the transcriptional activities of Alp, Opn, and Oc. The addition of Runx2 resulted in the 2- to 6-fold increase of the activities. This means that these two transcription factors have a synergistic effect on the osteoblast differentiation markers. Furthermore, early introduction of these two Runx2 and MEF factors significantly elevated the expression of the Opn mRNA levels in ROS cells. We also showed that Runx2 and MEF proteins physically interact with each other. CONCLUSIONS: Runx2 interacts with MEF proteins and binds to the promoters of the osteoblast markers such as Opn nearby MEF to increase its transcriptional activity. Our results also imply that osteoblast differentiation and bone formation can be increased by activating MEF to elicit the synergistic effect of Runx2 and MEF.
Subject(s)
Animals , Humans , Rats , Alkaline Phosphatase , Antigens, Differentiation , Bone and Bones , Bone Morphogenetic Proteins , Cell Differentiation , Cell Proliferation , Core Binding Factor Alpha 1 Subunit , Erythroblasts , Luciferases , Osteoblasts , Osteocalcin , Osteogenesis , Osteopontin , Polymerase Chain Reaction , Proteins , RNA, Messenger , Transcription Factors , TransfectionABSTRACT
Objective To investigate the role of recombinant human interleukin 6 (rhlL-6) in calcification and osteogenic transition of cultured human umbilical artery smooth muscle cells (HUASMC), and the possible cell signal transduction way. Methods HUASMCs were isolated by the explant method. HUASMCs were treated with (treatment groups) or without (control group) rhIL-6. Alizarin Red S stain was applied for calcium deposition in extracellular matrix of control ceils and the cells treated with rhIL-6 50 μg/L at day 12. Calcium concentration in cell layer of control group and treatment group (treated with rhIL-6 10 μg/L and 50 μg/L, respectively) was determined calorimetrically by the o-cresolphthalein complexone method at day 3, 6, 9 and 12, and corrected by total cell proteins. The mRNA expressions of bone-specific alkaline phosphatase (BAP), osteopontin (OPN), bone morphogenetic protein-2 (BMP2) and osteoprotegerin (OPG) were estimated by real-time PCR in 12, 24 and 72 hours. OPN, BMP2 and OPG expressions were assessed by Western blotting and the BAP concentration at the same time was checked by fluorometry method . Electrophoretie mobility shift assays (EMSA) was used to detect the binding activity of transcription factor Cbfα1 with or without inhibitors of p38-MAPK (SB203580) and PKC (DHC) after 6 hours stimulation by rhIL-6 10 μg/L. Results rhIL-6 induced a positive Alizarin Red S stain and a time-dose-dependent increasing of cell layer calcium deposition.Compared with control group, rhIL-6 10 μg/L enhanced gene expression and protein levels of BAP and BMP2 at the early time (12 and 24 hours), and of OPN and OPG at later hours (24 and 72 hours). RhIL-6 still induced an increasing of binding activity of Cbfα1, which could be partially blocked by DHC but not SB203580. Conclusions rhIL-6 induces HUASMCs calcification and osteogenie transition in vitro, which may be one of the mechanism involved in IL-6 associated vascular calcification as observed in clinical studies. The role of IL-6 in HUASMCs may partially achieved through the PKC cell signal transduction way.
ABSTRACT
Objective To investigate the effects of 17?-estradiol (E2) on the gene expression of typeⅠA bone morphogenetic protein receptor (BMPR-ⅠA) and core-binding factor alpha 1 (Cbf?1) in rat bone marrow stromal cells exposed to the differentiation medium and to elucidate the effects of E2 on osteoblastogenesis. Methods Adherent bone marrow stromal cells were cultured in differentiation medium containing DEX (10 -7 mol/L), 1,25-(OH)2D3 (10 -9 mol/L) and different concentrations of E2. Effects of different concentrations of E2 on the gene expression of BMPR-ⅠA and Cbf?1 was quantified by RT-PCR based on the comparison with an internal reference, ?-actin expression, and identified by Northern blotting. Alkaline phosphatase (ALP) activity of cells was detected. Contents of type Ⅰ collagen were determined by Van Gieson staining. Results E2 could evidently inhibit the expression of BMPR-ⅠA and Cbf?1 mRNA during the differentiation process of bone marrow stromal cells into osteoblasts in a dose-dependent manner. These were confirmed by Northern blotting. The ALP activity increased in a concentration-dependent manner, but the amount of type Ⅰ collagen decreased in a concentration-dependent manner. Conclusion E2 can significantly inhibit the gene expression of BMPR-ⅠA and Cbf?1 in bone marrow stromal cells and inhibit osteoblastogenesis in vitro.