Cbfa1 Gene Research Articles

R.T.R® promotes bone marrow mesenchymal stem cells osteogenic differentiation by upregulating BMPs/SMAD induced cbfa1 expression.

Bone marrow mesenchymal stem cells (BMSCs) of rats were isolated and Bio-Oss® and R.T.R® materials were used in this study.Alkaline phosphatase (ALP) activity in each group was calculated. The ability of adhesion and proliferation of BMSCs on Bio-Oss® and R.T.R® increased with time, but they were significantly higher on R.T.R® than that of Bio-Oss® at all time points (p<0.05). Compared with Bio-Oss®, R.T.R® could promote the expression and activity of ALP in BMSCs, and the expression of bone formation related transcription factors bone morphogenetic protein-1 (BMP-1), Cbfa1 and osteoblast marker genes ALP, collagen I, osteopontin, osseomucin and osteocalcin. The expression levels of cbfa1, ALP, collagen I, osteopontin, osseomucin and osteocalcin were inhibited after downregulated expression of BMP-1 in BMSCs and inoculation with R.T.R®. R.T.R® could up-regulate BMP-1 expression and cbfa1 expression through BMPs/SMAD signaling pathway, thereby promoting the expression of ALP, collagen I, osteopontin, osseomucin and osteocalcin and promoting osteoblast differentiation.

Cleidocranial Dysplasia-A Case Report

Cleidocranial dysplasia is a rare congenital disease. It is characterized by autosomal dominant inheritance pattern which is caused due to mutations in the Cbfa1 gene (Runx2) located on chromosome 6p21. It primarily affects bones which are formedby intra-membranous ossification and have equal sex distribution. It is also known as Marie and Sainton disease, Mutational dysostosis and cleidocranialdysostosis. The skeletal deformities of cleidocranial dysplasia are characterized by partial or complete absence of clavicles, late closure of the fontanels, presence of open skull sutures and multiple wormian bones. This rare syndrome is of utmost importance in dentistry due to presence of multiple supernumerary teeth, facial bones deformities and deranged eruption patterns. We are reporting a classical case of cleidocranial dysplasia in 20 year old patient.

Abstract 529: Cbfa1 (Runx2) is a Mediator of Aortic Stiffness and Hypertension in a Murine Model of Diabetes Mellitus Type 2

Accelerated arterial stiffening is a complication of diabetes mellitus and associated with the development of hypertension. Arterial stiffening results from extensive extracellular matrix remodeling (elastin breakdown, collagen accumulation). The osteogenic transcription factor Cbfa1 (Runx2) has been identified as a mediator of aortic calcification and regulator of matrix protein expression. However, its impact on aortic stiffness is unclear. This study was designed to elucidate the temporal relation between aortic stiffening and the development of arterial hypertension in a murine model of diabetes mellitus type 2. Moreover we aimed to investigate the role of Cbfa1 as potential mediator diabetic aortic stiffening. Serial ex vivo mechanical testing of the thoracic aorta and volume-pressure recording (VPR) based tail-cuff blood pressure measurements revealed that aortic stiffening precedes blood (pulse) pressure elevations in diabetic db/db mice. Vascular stiffening was accompanied by increased medial collagen deposition Picrosirius Red staining). qRT-PCR and immunohistochemistry revealed enhanced expression of Cbfa1 and target genes (Col1a1, Col1a2, FN1, Spp1) in db/db mice compared to controls. Moreover, overexpression of Cbfa1 in vascular smooth muscle (Cbfa1-smTg mice) results in increased medial collagen deposition, aortic stiffness and augmented pulse pressure. Interestingly, Cbfa1-smTg mice did not exhibit enhanced vascular calcification (by von Kossa and Alizarin Red staining). In conclusion we demonstrated that aortic stiffening precedes the onset of hypertension in db/db mice and identified Cbfa1 as mediator of aortic stiffening - presumably via pro-fibrotic mechanisms.

Stimulation of Osteogenic Differentiation in Stromal Cells of Giant Cell Tumour of Bone by Zoledronic Acid

Therapeutic effects of zoledronic acid (ZOL) on giant cell tumour of bone (GCT) have been proven. Apoptosis induction was considered to be one of the mechanisms of ZOL tumour inhibition. In this study, we presented the possibility of an osteogenic differentiation stimulation mechanism of ZOL and further investigated dosage and time effects. We treated stromal cells of GCT (GCTSC) with ZOL for 48 hours at different concentrations (0 μM, 0.01 μM, 0.1 μM, 1 μM, 5 μM, 30 μM) and assessed apoptotic and osteogenic differentiation markers with immunohistochemical techniques and real-time quantitative RT-PCR. Our results suggested that ZOL enhanced mRNA expression of Cbfa-1, osterix and osteocalcin genes with a maximum effect at 1 μM in GCTSC. Time course experiments indicated a time dependent osteogenic differentiation effect. In conclusion, ZOL may be considered as an adjuvant in the treatment of GCT not only by inducing apoptosis but also by stimulating osteogenic differentiation of remaining tumor stromal cells after surgery.

Insulin facilitates osteoblast differentiation

Tissue engineering of bone has been increasingly used in the bone defect repair. To generate osteoblasts is a major approach, and here we have examined ways of improving the efficiency of producing osteoblasts. Adipose stem cells (ADSC) were prepared from rat mesentery tissue, and transfected with Cbfa1 gene vector or/and IGF-1R gene vector. The cells were stimulated with insulin. Osteocalcin expression by the ADSCs was assessed by quantitative RT-PCR (qRT-PCR), Western blotting and enzyme-linked immunobosorbent assay. Both genes Cbfa1 and IGF-1R were transfected in ADSCs, as shown by qRT-PCR and Western blotting. Stimulation by insulin in the culture increased osteocalcin expression in ADSCs transfected by both Cbfa1 and IGF-1R, but not in those transfected with only one of these two genes. Osteocalcin in the culture supernatant was also increased by stimulation with insulin. Thus IGF-1R gene transfer together with insulin stimulation can markedly increase the efficiency of generation of osteoblasts.

The use of carbon nanotubes to induce osteogenic differentiation of human adipose-derived MSCs in vitro and ectopic bone formation in vivo

Carbon nanotubes (CNTs), one of the most concerned nanomaterials, with unique electrical, mechanical and surface properties, have been shown suitable for biomedical application. In this study, we evaluated attachment, proliferation, osteogenic gene expression, ALP/DNA, protein/DNA and mineralization of human adipose-derived stem cells cultured in vitro on multi-walled carbon nanotubes (MWNTs) and graphite (GP) compacts with the same dimension. Moreover, we assessed the effect of these two kinds of compacts on ectopic bone formation in vivo. First of all, higher ability of the MWNTs compacts to adsorb proteins, comparing with the GP compacts, was shown. During the conventional culture, it was shown that MWNTs could induce the expression of ALP, cbfa1 and COLIA1 genes while GP could not. Furthermore, alkaline phosphatase (ALP)/DNA and protein/DNA of the cell on the MWNTs compacts, was significantly higher than those of the cells on the GP compacts. With the adsorption of the proteins in culture medium with 50% fetal bovine serum (FBS) in advance, the increments of the ALP/DNA and protein/DNA for the MWNTs compacts were found respectively significantly more than the increments of those for the GP compacts, suggesting that the larger amount of protein adsorbed on the MWNTs was crucial. More results showed that ALP/DNA and protein/DNA of the cells on the two kinds of compacts pre-soaked in culture medium having additional rhBMP-2 were both higher than those of the cells on the samples re-soaked in culture medium with 50% FBS, and that those values for the MWNTs compacts increased much more. Larger mineral content was found on the MWNTs compacts than on the GP compacts at day 7. In vivo experiment showed that the MWNTs could induce ectopic bone formation in the dorsal musculature of ddy mice while GP could not. The results indicated that MWNTs might stimulate inducible cells in soft tissues to form inductive bone by concentrating more proteins, including bone-inducing proteins.

Cleidocranial dysplasia presenting with retained deciduous teeth in a 15-year-old girl: a case report

IntroductionCleidocranial dysplasia is a rare congenital defect of autosomal dominant inheritance caused by mutations in the Cbfa1 gene, also called Runx2, located on the short arm of chromosome 6. It primarily affects bones which undergo intramembranous ossification. This condition is of clinical significance to dentistry due to the involvement of the facial bones, altered eruption patterns and multiple supernumerary teeth.Case presentationOur patient, a 15-year-old Indian girl, presented with the typical features of prolonged retention of deciduous dentition and delayed eruption of permanent teeth, that is, mandibular prognathism along with other skeletal abnormalities like shrugged shoulder and the absence of clavicles. A multidisciplinary approach was followed, comprising orthodontic, surgical and pedodontic teams for management.ConclusionSuccessful treatment of such a case lies in a holistic approach that takes care of all aspects, including the primary pathology, the deformity itself and even the psychological angle.

Integrin‐associated tyrosine kinase FAK affects Cbfa1 expression

Following cell adhesion, focal adhesion kinase (FAK) autophosphorylates on tyrosine and regulates intracellular signaling cascades that regulate cell growth and differentiation. The hypothesis of this study was FAK mediates osteoblast differentiation dependent Cbfa1 expression. Slowly mineralizing UI and rapidly mineralizing UMR-106-01 BSP osteoblasts formed focal adhesions; however, the level of FAK in UI focal adhesions was less than that seen in BSP cells. UI cultures had less FAK expression (p < 0.05) along with elevated levels of FAK phosphotyrosine in comparison to rapidly mineralizing BSP cultures. Mineralization decreased in a dose-dependent manner in response to Herbimycin A, a tyrosine kinase inhibitor. Overexpression of FAK in UI cells led to a fourfold increase in Cbfa1 gene expression (p < 0.02), and an increase in Cbfa1 protein expression. These results suggest that the integrin-associated tyrosine kinase FAK contributes to the regulation of the osteoblast differentiation in part through the regulation of Cbfa1 expression.

Chemical modification of an implant surface increases osteogenesis and simultaneously reduces osteoclastogenesis: an in vitro study

The present study investigated the effect of a chemical modification of the SLA surface (SLActive surface) on human periodontal ligament (hPDL) cell (1) adhesion, (2) proliferation, (3) osteogenic differentiation (core binding factor α-1 [Cbfa-1], bone morphogenetic protein-7 [BMP-7] gene expression and alkaline phosphatase [ALP] activity) and (4) osteoclast formation and activity (osteoprotegerin [OPG] and receptor activator of nuclear factor-κ B ligand [RANKL] gene expression). The above activities were based on the hypothesis that the expression of such molecules might be dependent on the characteristics of the implant surface. hPDL cells were isolated and characterized for their mesenchymal origin, fibroblastic and osteoblastic phenotype. hPDL cells were cultured on smooth, SLA and SLActive implant surfaces (chemically modified). Cell attachment and proliferation were assessed for 5, 24, 72 h, 5 and 7 days. Cbfa-1, BMP-7, OPG and RANKL gene expression was assessed by RT-PCR and a colorimetric assay for ALP activity was applied. hPDL cells grown on SLActive surfaces demonstrated increased proliferation rates (24 h, 5 and 7 days of the incubation period), and ALP activity was found to be significantly upregulated (5, 72 h and 7 days) as compared with the SLA surfaces. After 7 days of culture, the gene expression of BMP-7, Cbfa-1 and OPG by hPDL cells was significantly upregulated, while RANKL gene expression was significantly downregulated in response to the SLActive surface. Chemical modification of a previously roughened implant surface increases hPDL proliferation and upregulates osteoblastic differentiation. It can also suppress osteoclastogenesis regulating the RANKL-RANK-OPG axis. Hence, an osteoprotective microenvironment is created around chemically modified implants that may enhance osseointegration.

Comparison of the osteogenic potential of equine mesenchymal stem cells from bone marrow, adipose tissue, umbilical cord blood, and umbilical cord tissue

To determine the optimal osteogenic source of equine mesenchymal stem cells (eMSCs) and optimize collection of and expansion conditions for those cells. 10 adult Quarter Horses and 8 newborn Thoroughbred foals. eMSCs were isolated from bone marrow (BM), adipose tissue, and umbilical cord blood and tissue, and the osteogenic potential of each type was assessed. Effects of anatomic site, aspiration volume, and serum type on eMSC yield from BM were investigated. BM-eMSCs had the highest overall expression of the osteogenic genes Cbfa1, Osx, and Omd and staining for ALP activity and calcium deposition. There was no significant difference in BM-eMSC yield from the tuber coxae or sternum, but yield was significantly greater from the first 60-mL aspirate than from subsequent aspirates. The BM-eMSC expansion rate was significantly higher when cells were cultured in fetal bovine serum instead of autologous serum (AS). eMSCs from BM possessed the highest in vitro osteogenic potential; eMSCs from adipose tissue also had robust osteogenic potential. The tuber coxae and the sternum were viable sources of BM-eMSCs in yearlings, and 60 mL of BM aspirate was sufficient for culture and expansion. Expanding BM-eMSCs in AS to avoid potential immunologic reactions decreased the total yield because BM-eMSCs grew significantly slower in AS than in fetal bovine serum. Additional studies are needed to determine optimal ex vivo eMSC culture and expansion conditions, including the timing and use of growth factor—supplemented AS.

Bone Regeneration Using an Acellular Extracellular Matrix and Bone Marrow Mesenchymal Stem Cells Expressing Cbfa1

To treat bone defects, tissue-engineering methods combine an appropriate scaffold with cells and osteogenic signals to stimulate bone repair. Mesenchymal stem cells (MSCs) derived from adult bone marrow are an ideal source of cells for tissue engineering, in particular for applications in skeletal and hard tissue repair. Core binding factor alpha1 (Cbfa1) is an essential transcription factor for osteoblast differentiation. However, the effects of Cbfa1 on MSCs in vitro and in vivo have not been well characterized. In this study, we found that MSCs modified genetically to express Cbfa1 promoted the healing of segmental defects of the radius in rabbits. First, osteogenic differentiation of MSCs transfected with an adenovirus encoding Cbfa1 was demonstrated. Expression of mRNA from a number of osteoblastic marker genes, including osteocalcin, osteopontin, and type I collagen, was detected. In addition, alkaline phosphatase activity and increased osteocalcin content were observed. The cells expressing the Cbfa1 gene were then combined with acellular bone extracellular matrix in a flow perfusion culture system. Finally, the cell-matrix constructs were implanted into radius defects in the rabbit model. After 12 weeks, radiographic, histological, and biomechanical analyses showed that MSCs modified with the Cbfa1 gene resulted in a significantly higher amount of newly-formed bone and rebuilding of the marrow cavity than control cell-matrix constructs. This study indicates that MSCs modified with the Cbfa1 gene can act as suitable seed cells for the regeneration of bone defects.

Putative heterotopic ossification progenitor cells derived from traumatized muscle

Heterotopic ossification (HO) is a frequent complication following combat-related trauma, but the pathogenesis of traumatic HO is poorly understood. Building on our recent identification of mesenchymal progenitor cells (MPCs) in traumatically injured muscle, the goal of this study was to evaluate the osteogenic potential of the MPCs in order to assess the role of these cells in HO formation. Compared to bone marrow-derived mesenchymal stem cells (MSCs), a well-characterized population of osteoprogenitor cells, the MPCs exhibited several significant differences during osteogenic differentiation and in the expression of genes related to osteogenesis. Upon osteogenic induction, MPCs showed increased alkaline phosphatase activity, production of a mineralized matrix, and up-regulated expression of the osteoblast-associated genes CBFA1 and alkaline phosphatase. However, MPCs did not appear to reach terminal differentiation as the expression of osteocalcin was not substantially up-regulated. With the exception of a few genes, the osteogenic gene expression profile of traumatized muscle-derived MPCs was comparable to that of the MSCs after osteogenic induction. These findings indicate that traumatized muscle-derived MPCs have the potential to function as osteoprogenitor cells when exposed to the appropriate biochemical environment and are the putative osteoprogenitor cells that initiate ectopic bone formation in HO.

Orthodontic Treatment in a Patient with Cleidocranial Dysostosis

Cleidocranial dysostosis is a rare congenital skeletal disorder, associated with clavicular hypoplasia or aplasia, delayed closure of cranial fontanels, brachycephalic skull, delayed exfoliation of primary dentition, eruption of permanent teeth, and multiple supernumerary and morphologic abnormalities of the maxilla and mandible. The disorder is caused by mutation in the CBFA1 gene, on the short arm of chromosome 6p21. The prevalence of cleidocranial dysostosis is estimated one per million, without sex or ethnic group predilection. The purpose of this paper is to describe the orthodontic treatment in a patient with cleidocranial dysostosis. Therapy may include removal of supernumerary teeth, surgical exposure of impacted teeth, and orthodontic treatment.

RNA interference of the BMPR‐IB gene blocks BMP‐2‐induced osteogenic gene expression in human bone cells

We have previously shown that human bone cells express bone morphogenetic protein receptor-IB (BMPR-IB). However, little is known about the precise role of this receptor in the response of osteoblastic genes to the BMP in these cells. To determine BMPR-IB-dependent osteoblastic gene expression, the present study examined the effects of BMPR-IB knockdown on BMP-induced osteoblast-associated genes. BMPR-IB mRNA and protein were markedly suppressed by transfection of cells with BMPR-IB siRNA. Using three different bone cell samples, BMP-2 stimulation of alkaline phosphatase (ALP), osteocalcin (OC), distal-less homeobox-5 (Dlx5) and core binding factor alpha-1 (Cbfa1) was found to be specifically and significantly reduced in the BMPR-IB siRNA-transfected cultures compared with that of control cultures. Our study has provided evidence that BMPR-IB-dependent signaling plays a crucial role in BMP-2 up-regulation of the ALP, OC, Dlx5 and Cbfa1 genes in bone cells, suggesting a pivotal role of this receptor in BMP-2-induced osteoblast differentiation in vitro. These findings thus suggest the possibility that BMPR-IB could be a therapeutic target for enhancing bone regeneration in vivo.

Craniofacial and temporal bone CT findings in cleidocranial dysplasia

Cleidocranial dysplasia (CCD) is a multistructural polyostotic genetic disorder that results from mutation of the CBFA1 gene. Hearing loss is a frequent finding in CCD. We describe the CT craniofacial findings in CCD and provide a comprehensive discussion of the CT temporal bone findings in these patients.

Expression and Function of Cbfa-1/Runx2 in Thyroid Papillary Carcinoma Cells

Development of calcifying foci is a common finding in human thyroid papillary carcinoma, but its mechanisms remain unknown. We therefore investigated whether osteocalcin and/or Cbfa-1 genes are expressed in malignant thyroid epithelial cells. We also studied the effects of Cbfa-1 on the expression of osteoblast-specific and thyrotropin receptor genes in thyrocytes. The human thyroid papillary carcinoma cell line BHP18-21 expresses bone-type osteocalcin mRNA at higher levels than in MG63 osteosarcoma cells. Northern blot analysis and EMSA using nuclear extracts from BHP18-21 cells and FRTL-5 cells demonstrated that cells of thyroid epithelial origin expressed Cbfa-1/Runx2, the main transcription factor for the expression of osteocalcin. When we transfected pcDNA3.1-human Cbfa-1 into FRTL-5 cells, Cbfa-1 increased the gene expression of alkaline phosphatase, type I collagen, and osteocalcin but suppressed the expression of thyrotropin receptor. We then stained the calcified regions of human papillary thyroid carcinoma tissues with antiosteocalcin antibody and found that malignant cells, as well as follicular epithelial cells, were immunopositive for osteocalcin. Northern blot analysis revealed that the Cbfa-1/Runx2 gene was strongly expressed in tissues from four cases of surgically resected papillary carcinoma. Thyrocytes share characteristics with osteoblasts. Cbfa-1 may play a role in calcification processes in human thyroid papillary carcinoma tissues.

Bone regeneration induced by adenoviral vectors carryingtil-1/Cbfa1 genes implanted with biodegradable porous materials in animal models of osteonecrosis of the femoral head

A new approach for bone regeneration is needed for idiopathic osteonecrosis of the femoral head (ION). Core binding factor alpha1 (Cbfa1) was reported in 1997 as the most important transcription factor for osteoblastic differentiation. The transgenics of transcription factors affecting bone formation might be useful tools for the bone regeneration. The purpose of this study was to investigate the effects of the implantation of adenoviral vectors carrying Cbfa1 genes implanted with biodegradable porous materials on bone formation in an animal model of ION. Robust and rapid bone regeneration in large bone defects was achieved with the implantation of adenoviral vectors carrying Cbfa1 genes. These results suggest that the Cbfa1 genes induce a rapid osteoblastic differentiation and the biodegradable scaffold successfully functioned as a delivery vehicle for the Cbfa1 gene, as they induced osteogenic repair in vivo, even in necrotic bone.

Experimental study of core binding factor a1 gene-modified rabbit skin fibroblasts enhance bone defect repair

To investigate bone defect healing by true bone ceramic complex carrying core binding factor a1 (Cbfa1) gene modified rabbit skin fibroblasts. Transfect rabbit skin fibroblasts (RSF) with both eukaryotic expression vector pSG5 which could express Cbfa1 gene and pSG5. After being cultured for 48 h, the transfected RSF were seeded into true bone ceramic (TBC) of 2 cm in length and 4 mm in diameter to construct pSG5-Cbfa1/RSF/TBC complex and pSG5/RSF/TBC complex. Forty-eight bone defect model rabbits were randomized into four groups, each has 6 rabbits (12 radius), due to different treatment. group I: with pSG5-Cbfa1/RSF/TBC complex, group II: with pSG5/RSF/TBC complex, group III: with TBC, Group IV: empty control. After being seeded and cultured for about 24 h the complexes were implanted into 2 cm long bone defects in the middle of bilateral radius of rabbits. The radius were inspected by X-ray and then the specimens were collected at the end of the fourth and twelfth weeks after operation. Then, the specimens were decalcified and histologically investigated with Hematoxylin eosin staining and Masson staining methods. Newly synthesized trabecular bone was inspected by image analysis system and the strength of bone defect area treated with graft-implantation was tested with biomechanical method-three point bending test. In group I, trabecular bone was actively synthesized to generate a great amount of trabecular bone and osteon. Preliminary union and bone defect healing were completed with good biomechanical characteristics. There were no newly synthesized trabecular in the other three groups, and bone defect healing were not discovered. The amount of newly synthesized trabecular bone and the results of biomechanical testing differed significantly between group I and the other three (P < 0.01). The efficacy of group I was significantly better than that of the other three groups. True bone ceramic complex composed with Cbfa1 gene modified rabbit skin fibroblasts can effectively heal bone defect in rabbits.

HTERT Transcription Is Repressed by Cbfa1 in Human Mesenchymal Stem Cell Populations

Human BMSSCs lose telomerase activity in vitro, which leads to chromosomal instability and cellular senescence. We observed an inverse expression pattern between the osteogenic master regulatory gene, CBFA1, and the stem cell-associated gene, hTERT. We showed that Cbfa1 acts as a partial repressor of TERT, which may facilitate cellular differentiation. The absence of telomerase activity by cultured human bone marrow stromal stem cells (BMSSCs) causes critical shortening of chromosomal telomeres, leading eventually to cellular senescence. Ex vivo expansion of BMSSCs correlates to an increase in osteogenic lineage associated markers such as alkaline phosphatase, bone sialoprotein, and osteocalcin that are regulated by the master regulatory transcription factor, Cbfa1 (Runx2). This study examined whether Cbfa1 was capable of regulating the promoter of the early stem cell-associated gene, telomerase reverse transcriptase (TERT). Human BMSSCs were isolated by fluorescence-activated cell sorting. Telomerase activity was determined using the telometric repeat amplification protocol. CBFA1 and TERT gene expression was assessed by real-time PCR. The functional capacity of Cbfa1 to bind to the hTERT promoter was performed using a modified electrophoretic mobility shift assay (EMSA). Chromatin immunoprecipitation (ChIP) analysis was used to examine Cbfa1 binding to the hTERT promoter in vivo. Functional analysis of CBFA-1 wildtype and mutant DNA binding sites on TERT promoter fragments was assessed using the promoterless green fluorescence protein (GFP) reporter vector, pEGFP-1, after transfection into HOS cells. This study showed an inverse expression pattern between the osteogenic master regulatory gene, CBFA1, and the stem cell-associated gene, hTERT. The data showed that BMSSCs undergo osteogenic commitment after the loss of hTERT expression, with concomitant elevated levels of CBFA1 transcripts. In addition, two unique Cbfa1 DNA binding sites were identified on the hTERT proximal promoter by EMSA supershift assay. Mutated forms of the putative Cbfa1 binding sites, created by site-directed mutagenesis, were able to abolish this interaction. ChIP analysis showed that Cbfa1 interacted directly with the hTERT promoter in vivo. Functional studies using GFP reporter constructs, driven by 2- and 3-kbp hTERT proximal promoter fragments, showed significantly lower levels of transcriptional activity compared with corresponding constructs with mutated Cbfa1 binding site Oligo 2. These studies suggest that Cbfa1 may act as a repressor of early stem cell markers such as hTERT as one possible mechanism for facilitating cellular differentiation.

Quantitative Analysis of Core Binding Factor 1 (Cbfa1) and Osteocalcin in C2C12 Cells Induced by Ca/P Ceramics In Vitro

The mRNA expression of Cbfa1 and osteocalcin gene induced by calcium phosphate ceramics (Ca/P) were quantitative analyzed according to real-time RT-PCR method in this work. C2C12 cells were co-culture with four kinds of porous Ca/P ceramics for 2 and 5d without adding other growth factors. The four kinds of Ca/P ceramics were pure hydroxyapatite (HA) sintered at 1250°C and HA/TCP with a ratio of 60/40 sintered at 1100°C (HT1), 1200°C (HT2) and 1250°C (HT3) respectively. Real-time RT-PCR analysis found the Ca/P ceramics induced positive expression of Cbfa1 and osteocalcin in C2C12 cells, After 5 days culture, Cbfa1 and osteocalcin showed obvious higher expression compared with that in 2 days. Cbfa1 and osteocalcin expression in BCP was much higher than HA, and the expression level of osteocalcin was HT1&gt;HT2&gt;HT3&gt;HA. Our results showed that Ca/P ceramics alone were sufficient to induce C2C12 cells to osteoblastic differentiation and the sinter temperature and phase composition of Ca/P ceramics could affect their osteoindctive capacity significantly.