OBJECTIVE: To investigate the effects of the Arg-Gly-Asp polypeptedes (RGD) peptides-modified porous tantalum surface on osteoblasts morphology and expressions of osteogenesis factors, and to evaluate RGD peptides promotes junctura ossium of tantalum-bone interface in vivo. METHODS: RGD peptides of different concentrations (1 g/L, 5 g/L, and 10 g/L) were loaded to porous tantalum slices with a diameter of 10 mm and a thickness of 3 mm by physical absorption. The 3rd generation of MG63 cells were co-cultured with tantalum and divided into 4 groups: Ta-cells (control) group, 1 g/L cells/Ta/RGD group, 5 g/L cells/Ta/RGD group, and 10 g/L cells/Ta/RGD group. Porous tantalum compo-sites and osteoblasts-tantalum interface were observed by scanning electron microscopy. The adhesion rate of osteoblasts was detected and immunocytochemistry was used to detect the expressions of filamentous actin (F-actin), osteocalcin (OC) and fibronectin (FN). RESULTS: The scanning electron microscope (SEM) revealed that osteoblasts distributed on the surface of porous tantalum and secreted extracellular matrix on outside and inner of micro-pores. The osteoblasts adhesion rate on porous tantalum modified with RGD was higher than that in the unmodified porous tantalum at the end of 24, 48, and 72 hours. The best adhesion effect was got in 5 g/L cells/Ta/RGD group at hour 48 [(68.07±3.80) vs. (23.40±4.39), P<0.05]. The results of immunocytochemistry showed that the expressions intensity of F-actin, OC and FN in osteoblasts on porous tantalum modified groups with RGD were stronger than that in the unmodified groups, and the expressions of 5 g/L cells/Ta/RGD group were significantly higher than those in the 10 g/L group and 1 g/L group [OC: (18.08±0.08) vs. (15.14±0.19), P<0.05; (18.08±0.08) vs. (14.04±0.61), P<0.05. FN: (24.60±0.98) vs. (15.90±0.53), P<0.05; (24.60±0.98) vs. (15.30±0.42), P<0.05. F-actin: (29.20±1.31) vs. (24.50±1.51), P<0.05; (29.20±1.31) vs. (16.92±0.40), P<0.05]. Correspondingly F-actin in osteoblasts was showed in longitudinal arrangement, and the expressions intensity was stronger than those OC and FN. CONCLUSION The RGD peptides is beneficial to enhance adhesion of osteoblast, spreading and reorganization of cytoskeleton on porous tantalum surface and improve the interface morphology, further promoting osteoblasts-tantalum conjunctive interface osseointegration.
Cell Adhesion ; Oligopeptides ; Osteoblasts/physiology* ; Osteogenesis ; Tantalum

Peroxisome proliferator activated receptor gamma interacts with bone morphogenetic protein, Wnt, TAZ, and insulin-like growth factor-I, which are required for the process of osteoblast differentiation, regulating the mesenchymal stem cells (MSCs) into adipocytes and osteoblasts differentiation, thus impact on the osteoblast-mediated bone formation in bone remodeling, and, through RANKL and other factors directly or indirectly, regulate osteoclast-mediated bone resorption. This article reviews new researches for the influence of peroxisome proliferator activated receptor gamma on osteoblast and osteoclast function in bone remodeling.
Bone Remodeling ; physiology ; Humans ; Osteoblasts ; physiology ; Osteoclasts ; physiology ; PPAR gamma ; physiology

Weight-bearing bone is constantly adapting its structure and function to mechanical environments. Loading through routine exercises stimulates bone formation and prevents bone loss, but unloading through bed rest and cast immobilization as well as exposure to weightlessness during spaceflight reduces its mass and strength. In order to elucidate the mechanism underlying unloading-driven bone adaptation, ground-based in vitro and in vivo analyses have been conducted using rotating cell culturing and hindlimb suspension. Focusing on gene expression studies in osteoblasts and hindlimb suspension studies, this minireview introduces our recent understanding on bone homeostasis under weightlessness in space. Most of the existing data indicate that unloading has the opposite effects to loading through common signaling pathways. However, a question remains as to whether any pathway unique to unloading (and not to loading) may exist.
Adaptation, Physiological ; Animals ; Bone and Bones ; cytology ; physiology ; Hindlimb Suspension ; physiology ; Humans ; Osteoblasts ; physiology ; Weightlessness

This study was aimed to investigate the biological characteristics of osteoblasts and their hematopoietic supportive function by using human fetal osteoblastic cell line 1.19 (hFOBs) as a model. The pluripotency markers (Oct-4, Rex-1, hTERT) of hFOBs were analyzed by RT-PCR, the multilineage differentiation experiments were conducted in vitro. Flow cytometry (FCM) was used to identify the surface markers of hFOBs, and RT-PCR was used to analyze their hematopoietic cytokine expression in comparison with bone marrow mesenchymal stem cell (BM-MSC). The results showed that hFOBs expressed several ESC pluripotency markers including Oct-4 and Rex-1, except hTERT. Moreover, hFOBs could also undergo multilineage differentiation into the mesodermal lineages of adipocytic cell types in addition to its predetermined pathway, the mature osteoblast. Both hFOBs and BM-MSC expressed CD44, CD73 (SH3), CD105 (SH2) and CD90 (Thy1), and lack expression of CD34, CD45, or HLA-DR surface molecules. In addition, both hFOBs and BM-MSC expressed SCF, IL-6, and SDF-1alpha mRNA, but only hFOBs could express GM-CSF and G-CSF. It is concluded that human fetal osteoblastic cell line 1.19 may provide a good model to study the osteoblastic regulation role in hematopoiesis in vitro.
Cell Differentiation ; physiology ; Cell Line ; Fetus ; Hematopoiesis ; physiology ; Humans ; Mesenchymal Stromal Cells ; cytology ; physiology ; Models, Biological ; Osteoblasts ; cytology ; physiology

Bidirectional Eph-Ephrin signaling as a focal point of research in cell-cell communications is critical for generation of nerves and vesssels as well as invation and metastasis of tumor cells. The roles for Ephrin-Eph bidirectional signaling in bone remodeling were important. EphrinB2 is expressed on osteoblasts and EphB4 is expressed on osteoclasts. Forward signaling through the EphB4 receptor into mesenchymal precursors promotes osteoblast differentiation, while reverse signaling through the EphrinB2 ligand into osteoclast suppresses differentiation. Signaling between the ligand EphrinB2 and the receptors EphB4 explains bidirectional signaling between osteoblasts and osteoclasts,bone absorption and remodeling, which may lay a theoretical foundation for identifying drug targeting and preventing and treating bone loss.
Animals ; Bone Remodeling ; physiology ; Ephrin-B2 ; physiology ; Humans ; Osteoblasts ; cytology ; Osteoclasts ; cytology ; Receptor, EphB4 ; physiology ; Signal Transduction ; physiology

OBJECTIVETo explore the effects and mechanism of mesangial cell (MC) on proliferation and function of osteoblast in vitro from growth factors.

METHODSOsteoblast cultured in vitro were divided into normal blood serum group and MC group and cultured supernatant fluid by 10% serum culture medium and 20% MC culture medium. MTF was used to checked the proliferation of osteoblast at the end of 24, 48, 72, 120 h; Expression of BGP and OPN were tested 72 h and 144 h after culture; Expression of IGF-alpha and TGF-beta were tested 144 h after culture.

RESULTSThe proliferation of osteoblast in MC group was obviously higher than normal blood serum group in different times (P < 0.05); The level of BGP and OPN of osteoblast was obviously higher than normal blood serum group (11.3%, 16.4%, 55.0% and 39.6%); and the level of IGF-alpha and TGF-beta of osteoblast was obviously higher than normal blood serum group (10.1% and 47.7%).

CONCLUSIONMC can directly act on osteoblast, promote the proliferation and function of osteoblast by promoting secretion of TGF-beta.

Animals ; Cell Proliferation ; Male ; Mesangial Cells ; physiology ; Osteoblasts ; physiology ; Osteopontin ; physiology ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta ; physiology

Bone tissure engineering plays an important role in tissure engineering. It typically uses an osteoblasts, artificial extracellular matrix (scaffold), and osteoinductive factors which promote cell attachment, differentiation, and mineralized bone formation. So it contents three problems at least: osteoblasts culture in vivo and in vitro, scaffold studies and regulation factors. Bone defect caused by trauma, tumor and inflammation is a frequent and formidable problem in clinical orthopedics. It appears that artificial bone produced by bone tissure engineering can save the problem well. With the development of tissue engineering, bone tissue engineering is developing rapidly. However, seldom experiments are on human body, and fewer productions of bone tissure engineering are used in clinic.
Animals ; Bone and Bones ; physiology ; Cell Differentiation ; Humans ; Osteoblasts ; physiology ; Osteogenesis ; Tissue Engineering ; trends ; Tissue Scaffolds

Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that microRNAs (miRNAs), known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression, and growing numbers of novel miRNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis, and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of miRNAs in regulating bone remodeling as well as novel applications for miRNAs in biomaterials for therapeutic purposes.
Animals ; Bone Remodeling ; physiology ; Cell Lineage ; Humans ; MicroRNAs ; physiology ; Osteoblasts ; cytology ; Transcription, Genetic

Nephronectin (NPNT) is a novel extracellular matrix protein and a new ligand of integrin α8β1. Recent studies showed that NPNT is highly expressed in kidney, lung, thyroid, etc, and it may play an important role in many pathological conditions. NPNT is involved in the process of kidney development and acute kidney injury, regulates proliferation and differentiation of osteoblast, and induces the vasculogenesis in vitro. NPNT may play a key role in pathological osteoporosis and therefore be a new therapeutic target of bone diseases. NPNT gene variants are not only associated with lung function, but also potentially implicated in chronic airway diseases development. Moreover, NPNT is also an important factor that mediates pathology of cardiac, epidermis, breast, liver and teeth diseases. In this paper, we reviewed some research progresses on the structure, distribution, physiological and pathophysiological functions of NPNT.
Cell Differentiation ; Cell Proliferation ; Extracellular Matrix Proteins ; physiology ; Humans ; Kidney ; physiology ; Osteoblasts ; cytology ; Osteoporosis

OBJECTIVE: This study aimed to investigate the effect of calcium ion (Ca²⁺) on the migration and osteogenic differentiation of human osteoblasts and explore the proper concentration and correlation mechanism. METHODS: A series of Ca²⁺ solutions with different concentrations was prepared. Osteoblast migration was assessed by Transwell assay, and proliferation was studied via the CCK-8 colorimetric assay. The mRNA expression of osteogenic genes was examined via reverse transcription-polymerase chain reaction (RT-PCR), and the mineralized nodule was examined by alizarin red-S method. After calcium sensitive receptor (CaSR) antagonism, Ca²⁺-induced migration and osteogenic differentiation were analyzed. RESULTS: In the migration experiment, 2, 4, and 6 mmol·L⁻¹ Ca²⁺ could promoted osteoblast migration at three timepoints (8, 16, and 24 h), whereas 10 mmol·L⁻¹ Ca²⁺ considerably inhibited migration at 8 h. The Ca²⁺ concentration range of 2-10 mmol·L⁻¹ could promote proliferation, osteogenic differentiation, and mineralization of human osteoblasts. Moreover, mineralization was predominantly induced by 8 and 10 mmol·L⁻¹ Ca²⁺. CaSR antagonism could reduce Ca²⁺-induced migration and osteogenic differentiation of human osteoblasts. CONCLUSIONS Low Ca²⁺ concentration favored osteoblast migration, whereas high Ca²⁺ concentration favored osteogenic differentiation. The Ca²⁺ concentrations of 4 and 6 mmol·L⁻¹ could substantially induce osteoblast migration and osteogenic differentiation, and the Ca²⁺-CaSR pathway participated in signal transduction.
Calcium ; physiology ; Cell Differentiation ; Cell Movement ; Cell Proliferation ; Humans ; Osteoblasts ; Osteogenesis ; physiology ; Signal Transduction