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TheScientificWorldJournal Apr 2010Bone tissue renovation is a dynamic event in which osteoblasts and osteoclasts are responsible for the turnover between bone formation and bone resorption, respectively.... (Review)
Review
Bone tissue renovation is a dynamic event in which osteoblasts and osteoclasts are responsible for the turnover between bone formation and bone resorption, respectively. During bone development, extracellular matrix remodeling is required for osteoblast differentiation and the process is largely mediated by the proteolytic activity of extracellular matrix metalloproteinases (MMPs), which play a fundamental role in osteoblast migration, unmineralized matrix degradation, and cell invasion. The recent advances towards investigation in osteogenesis have provided significant information about the transcriptional regulation of several genes, including MMPs, by the expression of crucial transcription factors like NFAT, ATF4, osterix, TAZ, and Cbfa-1-responsive elements. Evidence from gene knock-out studies have shown that bone formation is, at least in part, mediated by nitric oxide (NO), since mice deficient in endothelial nitric oxide synthase (eNOS) and mice deficient in the eNOS downstream effector (cGMP)-dependent protein kinase (PKG) show bone abnormalities, while inducible NOS (iNOS) null mice also show imbalances in bone osteogenesis and abnormalities in bone healing. Recently, in vitro data showed that Cbfa-1 and the MAPK pathways were crucial for osteoblastic cell differentiation, and NO was found to play a significant role. This article sheds light on some of the mechanisms that may influence NO-mediated actions in bone development.
Topics: Animals; Bone Development; Cell Differentiation; Cell Proliferation; Mice; Nitric Oxide; Osteoblasts; Transcription Factors
PubMed: 20419275
DOI: 10.1100/tsw.2010.58 -
Biomaterials Aug 2004Aseptic loosening and osteolysis are currently the most common causes of failure of total joint replacements. Osteolysis is initiated by a macrophage response to wear... (Comparative Study)
Comparative Study
Aseptic loosening and osteolysis are currently the most common causes of failure of total joint replacements. Osteolysis is initiated by a macrophage response to wear debris, resulting in localized, osteoclastic peri-implant bone loss. We have previously inhibited osteoclast-mediated bone resorption in a canine total hip arthroplasty model using oral bisphosphonate therapy. Based on serendipitous observations from our canine study, we hypothesized that bisphosphonates have an anabolic effect on osteoblasts, in a manner distinct from their inhibitory effect on osteoclastic bone resorption. We studied the anabolic effects of two FDA-approved bisphosphonates (alendronate and risedronate) on two in vitro models: a primary human trabecular bone cell culture and the MG-63 osteoblast-like cell line. Following treatment with bisphosphonates at varying concentrations and time periods, cells were assayed for proliferation effects and results were quantified using the methods of direct cell count, and the colorimetric MTT (3-dimethylthiazol-2,5-diphenyltetrazolium bromide) assay at 24, 48, and 72 h. The effect of bisphosphonates on the maturation of osteoblasts were tested with alkaline phosphatase bioassay and reverse transcription-polymerase chain reaction for markers of osteoblast differentiation. Results from both the primary human trabecular bone cell culture and the MG-63 osteoblast-like cell line showed that both bisphosphonates significantly increased the cell number over controls, attaining peak levels at a concentration of 10(-8)M. Alkaline phosphatase activity was also increased, representing earlier commitment of osteoprogenitor cells towards the osteoblastic phenotype. Bisphosphonates also enhanced gene expression of BMP-2, Type I collagen and osteocalcin. In summary, bisphosphonates, aside from their role as inhibitors of osteoclastic bone resorption, are promoters of osteoblast proliferation and maturation.
Topics: Adaptation, Physiological; Alendronate; Cell Differentiation; Cell Division; Cell Line; Cell Survival; Cells, Cultured; Diphosphonates; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Etidronic Acid; Extracellular Matrix Proteins; Humans; Osteoblasts; Risedronic Acid
PubMed: 15046901
DOI: 10.1016/j.biomaterials.2003.11.024 -
Journal of Materials Science. Materials... Mar 2019Robust cell adhesion is known to be necessary to promote cell colonization of biomaterials and differentiation of progenitors. In this paper, we propose the...
Robust cell adhesion is known to be necessary to promote cell colonization of biomaterials and differentiation of progenitors. In this paper, we propose the functionalization of Silicon Oxycarbide (SiOC) nanowires (NWs) with 3-mercaptopropyltrimethoxysilane (MPTMS), a molecule containing a terminal -SH group. The aim of this functionalization was to develop a surface capable to adsorb proteins and promote cell adhesion, proliferation and a better deposition of extracellular matrix. This functionalization can be used to anchor other structures such as nanoparticles, proteins or aptamers. It was observed that surface functionalization markedly affected the pattern of protein adsorption, as well as the in vitro proliferation of murine osteoblastic cells MC3T3-E1, which was increased on functionalized nanowires (MPTMS-NWs) compared to bare NWs (control) (pā<ā0.0001) after 48āh. The cells showed a better adhesion on MPTMS-NWs than on bare NWs, as confirmed by immunofluorescence studies on the cytoskeleton, which showed a more homogeneous vinculin distribution. Gene expression analysis showed higher expression levels for alkaline phosphatase and collagen I, putative markers of the osteoblast initial differentiation stage. These results suggest that functionalization of SiOC nanowires with MPTMS enhances cell growth and the expression of an osteoblastic phenotype, providing a promising strategy to improve the biocompatibility of SiOC nanowires for biomedical applications.
Topics: Animals; Cell Adhesion; Cell Differentiation; Cell Proliferation; Cell Survival; Cells, Cultured; Materials Testing; Mice; Nanowires; Organosilicon Compounds; Osteoblasts; Osteogenesis; Photoelectron Spectroscopy; Silanes; Silicon Compounds; Sulfhydryl Compounds; Surface Properties; Tissue Scaffolds
PubMed: 30929122
DOI: 10.1007/s10856-019-6241-y -
Bio-medical Materials and Engineering 2008Porous polyethylene (PP or Medpor) is an alloplastic material worldwide used for craniofacial reconstruction. Although several clinical studies are available, there is a...
Porous polyethylene (PP or Medpor) is an alloplastic material worldwide used for craniofacial reconstruction. Although several clinical studies are available, there is a lack as regard the genetic effects. Because PP is always fixed on bone and the mechanism by which PP acts on osteoblasts is unknown, we therefore attempted to address this question by using microRNA microarray techniques to investigate the translation regulation in osteoblasts exposed to PP. The miRNA oligonucleotide microarray provides a novel method to carry out genome-wide microRNA profiling in human samples. By using miRNA microarrays containing 329 probe designed from Human miRNA sequence, we identified in osteoblast-like cells line (MG-63) cultured with Medpor (Porex Corporation, Fairburn, Georgia, USA) several miRNA which expression is significantly modified. We identified 16 up-regulated miRNA (i.e. mir-337, mir-515-3p, mir-377, mir-153, mir-367, mir-152, let-7b, mir-92, mir-155, mir-424, mir-148b, mir-368, mir-18b, mir-520d, mir-20b, mir-128a) and 2 down-regulated miRNA (i.e. mir-143, mir-32). The data reported are, to our knowledge, the first study on translation regulation in osteoblasts exposed to PP. They can be relevant to better understand the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.
Topics: Absorbable Implants; Biocompatible Materials; Bone Remodeling; Cells, Cultured; Gene Expression Profiling; Gene Expression Regulation; Humans; MicroRNAs; Oligonucleotide Array Sequence Analysis; Osteoblasts; Polyethylenes
PubMed: 18408260
DOI: No ID Found -
Clinical and Experimental Pharmacology... Jan 2018Non-steroidal anti-inflammatory drugs (NSAIDs) exert their effects primarily by inhibiting the activity of cyclooxygenase (COX), thus suppressing prostaglandin...
Non-steroidal anti-inflammatory drugs (NSAIDs) exert their effects primarily by inhibiting the activity of cyclooxygenase (COX), thus suppressing prostaglandin synthesis. Some NSAIDs are known to perform functions other than pain control, such as suppressing tumour cell growth, independent of their COX-inhibiting activity. To identify NSAIDs with COX-independent activity, we examined various NSAIDs for their ability to inhibit osteoblastic differentiation using the mouse pre-osteoblast cell line MC3T3-E1. Only celecoxib and valdecoxib strongly inhibited osteoblastic differentiation, and this effect was not correlated with COX-inhibiting activity. Moreover, 2,5-dimethyl (DM)-celecoxib, a celecoxib analogue that does not inhibit COX activity, also inhibited osteoblastic differentiation. Celecoxib and DM-celecoxib inhibited osteoblastic differentiation induced by bone morphogenetic protein (BMP)-2 in C2C12 mouse myoblast cell line. Although celecoxib suppresses the growth of some tumour cells, the viability and proliferation of MC3T3-E1 cells were not affected by celecoxib or DM-celecoxib. Instead, celecoxib and DM-celecoxib suppressed BMP-2-induced phosphorylation of Smad1/5, a major downstream target of BMP receptor. Although it is well known that COX plays important roles in osteoblastic differentiation, these results suggest that some NSAIDs, such as celecoxib, have targets other than COX and regulate phospho-dependent intracellular signalling, thereby modifying bone remodelling.
Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Bone Morphogenetic Protein 2; Celecoxib; Cell Differentiation; Cell Proliferation; Cell Survival; Cyclooxygenase 2; Mice; Osteoblasts; Signal Transduction
PubMed: 28815657
DOI: 10.1111/1440-1681.12846 -
Journal of Cellular Biochemistry Nov 1994The cells of bone are of two lineages, the osteoblasts arising from pluripotential mesenchymal cells and osteoclasts from hemopoietic precursors of the... (Review)
Review
The cells of bone are of two lineages, the osteoblasts arising from pluripotential mesenchymal cells and osteoclasts from hemopoietic precursors of the monocyte-macrophage series. Resorption of bone by the multinucleate osteoclast requires the generation of new osteoclasts and their activation. Many hormones and cytokines are able to promote bone resorption by influencing these processes, but they achieve this without acting directly on osteoclasts. Most evidence indicates that their actions are mediated by cells of the osteoblast lineage. Evidence for hormone- and cytokine-induced activation of osteoclasts requiring the mediation of osteoblasts comes from studies of resorption by isolated osteoclasts. However, consistent evidence for a specific "activating factor" is lacking, and the argument is presented that the isolated osteoclast resorption assays have not been shown convincingly to be assays of osteoclast activation. The view is presented that osteoblast-mediated osteoclast activation is the result of several events in the microenvironment without necessarily requiring the existence of a specific, essential osteoclast activator. On the other hand, a specific promoter of osteoclast differentiation does seem likely to be a product of cells of the stromal/osteoblast series. Evidence in favour of this comes from studies of osteoclast generation in co-cultures of osteoblast/stromal cells with hemopoietic cells. Conflicting views, maintaining that osteoclasts can develop from hemopoietic cells without stromal intervention, might be explained by varying criteria used in identification of osteoclasts. Osteoblastic and osteoclastic renewal, and the interactions of these lineages, are central to the process of bone remodeling.
Topics: Animals; Bone Resorption; Cell Differentiation; Cytokines; Hormones; Humans; Models, Biological; Osteoblasts; Osteoclasts; Osteogenesis
PubMed: 7876329
DOI: 10.1002/jcb.240560312 -
Mayo Clinic Proceedings Jan 2000The relative contributions of androgens and estrogen to bone metabolism are still being defined. To directly assess androgen effects on bone cells, we have developed... (Review)
Review
The relative contributions of androgens and estrogen to bone metabolism are still being defined. To directly assess androgen effects on bone cells, we have developed human osteoblastic cell models expressing the androgen receptor. This approach is distinct from studies that have used a variety of transformed cell lines, in that the latter studies showed variability in the results. Investigation into androgen effects on bone has been overshadowed by interest in estrogen effects.
Topics: Androgens; Animals; Cell Differentiation; Cell Division; Cell Line; Cytokines; Estrogens; Growth Substances; Humans; Osteoblasts; Rats; Receptors, Androgen; Receptors, Estrogen
PubMed: 10959217
DOI: No ID Found -
Cell Proliferation Jun 2017Stiffness of bone tissue differs response to its physiological or pathological status, such as osteoporosis or osteosclerosis. Consequently, the function of cells...
OBJECTIVES
Stiffness of bone tissue differs response to its physiological or pathological status, such as osteoporosis or osteosclerosis. Consequently, the function of cells residing in bone tissue including osteoblasts (OBs), osteoclasts and osteocytes will be affected. However, to the best of our knowledge, the detailed mechanism of how extracellular matrix stiffness affects OB function remains unclear.
MATERIALS AND METHODS
We conducted a study that exposed rat primary OBs to polydimethylsiloxane substrates with varied stiffness to investigate the alterations of cell morphology, osteoblastic differentiation and its potential mechanism in mechanotransduction.
RESULTS
Distinctive differences of cell shapes and vinculin expression in rat osteoblasts were detected on different PDMS substrates. As representatives for OB function, expression of alkaline phosphatase, Runx2 and osteocalcin were identified and showed a decrease trend as substrates become soft, which is associated with the Rho/ROCK signalling pathway.
CONCLUSIONS
Our results indicated substrate elasticity as a potent regulator in OBs functionalization, which may pave a way for further understanding of bone diseases as well as a potential therapeutic alternative in tissue regeneration.
Topics: Animals; Cell Differentiation; Cells, Cultured; Extracellular Matrix; Osteoblasts; Rats
PubMed: 28205330
DOI: 10.1111/cpr.12338 -
Journal of Cell Science Jun 1996The extracellular matrix protein tenascin is secreted by osteoblasts but absent from mineralized bone matrix. The current study was undertaken to test the hypothesis...
The extracellular matrix protein tenascin is secreted by osteoblasts but absent from mineralized bone matrix. The current study was undertaken to test the hypothesis that tenascin regulates osteoblast behaviour. Three osteoblast-like cell lines UMR-106, ROS-17/2.8 (rat) and SAOS-2 (human) were used to investigate the role of tenascin in osteoblast morphology, differentiation and proliferation. Two of three cell lines adhered specifically to tenascin, remaining round and failing to spread. Tenascin as a substratum stimulated alkaline phosphatase activity (a marker of osteoblast differentiation) in two of three cell lines. Moreover, anti-tenascin in the medium caused a reduction in alkaline phosphatase levels in all three cell lines. Anti-tenascin also inhibited collagen synthesis, an important osteoblast function. Since it seemed possible that tenascin may exert its effects on cell function through its ability to cause cell rounding, the ability of cell shape change alone to influence alkaline phosphatase levels was investigated. Cells were incubated in the presence of cytochalasin D and alkaline phosphatase levels assayed. Alkaline phosphatase activity was not elevated by cytochalasin D treatment, indicating that cell rounding alone is insufficient to mimic the effect of tenascin. Anti-tenascin caused a slight increase in proliferation of SAOS-2 cells, indicating that tenascin is itself inhibitory. In ROS 17/2.8 and UMR-106 cells, in contrast, proliferation was inhibited by anti-tenascin. The results presented here indicate that tenascin is able to stimulate osteoblastic differentiation and that endogenous tenascin helps to maintain the functional state of cultured osteoblast-like cells.
Topics: Alkaline Phosphatase; Animals; Antibodies; Cell Adhesion; Cell Differentiation; Cell Division; Cell Line; Cell Size; Cytochalasin D; Humans; Kinetics; Nucleic Acid Synthesis Inhibitors; Osteoblasts; Rats; Tenascin
PubMed: 8799846
DOI: 10.1242/jcs.109.6.1597 -
PloS One 2018MicroRNAs (miRNAs) are important regulators of many cellular processes, including the differentiation and activity of osteoblasts, and therefore, of bone turnover....
MicroRNAs (miRNAs) are important regulators of many cellular processes, including the differentiation and activity of osteoblasts, and therefore, of bone turnover. MiR-320a is overexpressed in osteoporotic bone tissue but its role in osteoblast function is unknown. In the present study, functional assays were performed with the aim to elucidate the mechanism of miR-320a action in osteoblastic cells. MiR-320a was either overexpressed or inhibited in human primary osteoblasts (hOB) and gene expression changes were evaluated through microarray analysis. In addition, the effect of miR-320a on cell proliferation, viability, and oxidative stress in hOB was evaluated. Finally, matrix mineralization and alkaline phosphatase activity were assessed in order to evaluate osteoblast functionality. Microarray results showed miR-320a regulation of a number of key osteoblast genes and of genes involved in oxidative stress. Regulation of osteoblast differentiation and ossification appeared as the best significant biological processes (PANTHER P value = 3.74E-05; and P value = 3.06E-04, respectively). The other enriched pathway was that of the cellular response to cadmium and zinc ions, mostly by the overexpression of metallothioneins. In hOBs, overexpression of miR-320a increased cell proliferation and oxidative stress levels whereas mineralization capacity was reduced. In conclusion, overexpression of miR-320a increased stress oxidation levels and was associated with reduced osteoblast differentiation and functionality, which could trigger an osteoporotic phenotype.
Topics: Cell Differentiation; Cell Proliferation; Cells, Cultured; Gene Expression Regulation; Humans; MicroRNAs; Osteoblasts; Osteoporosis; Oxidative Stress; Up-Regulation
PubMed: 30485349
DOI: 10.1371/journal.pone.0208131