Alpha-adrenergic blocker mediated osteoblastic stem cell differentiation

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Choi, Yoon Jung [Craniomaxillofacial Reconstructive Sciences Major, College of Dentistry, Seoul National University, Seoul 110-749 (Korea, Republic of); Lee, Jue Yeon [Craniomaxillofacial Reconstructive Sciences Major, College of Dentistry, Seoul National University, Seoul 110-749 (Korea, Republic of); Research Center, Nano Intelligent Biomedical Engineering Corporation (NIBEC), Seoul (Korea, Republic of); Lee, Seung Jin [Department of Industrial Pharmacy, College of Pharmacy, Ewha Womans University, Seoul (Korea, Republic of); Research Center, Nano Intelligent Biomedical Engineering Corporation (NIBEC), Seoul (Korea, Republic of); Chung, Chong-Pyoung [Department of Periodontology, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Research Center, Nano Intelligent Biomedical Engineering Corporation (NIBEC), Seoul (Korea, Republic of); Park, Yoon Jeong, E-mail: parkyj@snu.ac.kr [Craniomaxillofacial Reconstructive Sciences Major, College of Dentistry, Seoul National University, Seoul 110-749 (Korea, Republic of); Research Center, Nano Intelligent Biomedical Engineering Corporation (NIBEC), Seoul (Korea, Republic of)

2011-12-16

Highlights: Black-Right-Pointing-Pointer Doxazocin directly up-regulated bone metabolism at a low dose. Black-Right-Pointing-Pointer Doxazocin induced osteoblastic stem cell differentiation without affecting cell proliferation. Black-Right-Pointing-Pointer This osteogenic stem cell differentiation is mediated by ERK-signal dependent pathway. -- Abstract: Recent researches have indicated a role for antihypertensive drugs including alpha- or beta-blockers in the prevention of bone loss. Some epidemiological studies reported the protective effects of those agents on fracture risk. However, there is limited information on the association with those agents especially at the mechanism of action. In the present study, we investigated the effects of doxazosin, an alpha-blocker that is clinically used for the treatment of benign prostatic hyperplasia (BPH) along with antihypertensive medication, on the osteogenic stem cell differentiation. We found that doxazosin increased osteogenic differentiation of human mesenchymal stem cells, detected by Alizarin red S staining and calcein. Doxazosin not only induced expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin, it also resulted in increased phosphorylation of extracellular signal-regulated kinase (ERK1/2), a MAP kinase involved in osteoblastic differentiation. Treatment with U0126, a MAP kinase inhibitor, significantly blocked doxazosin-induced osteoblastic differentiation. Unrelated to activation of osteogenic differentiation by doxazosin, we found that there were no significant changes in adipogenic differentiation or in the expression of adipose-specific genes, including peroxisome proliferator-activated receptor {gamma}, aP2, or LPL. In this report, we suggest that doxazosin has the ability to increase osteogenic cell differentiation via ERK1/2 activation in osteogenic differentiation of adult stem cells, which supports the protective effects of antihypertensive drug on fracture risk and

Alpha-adrenergic blocker mediated osteoblastic stem cell differentiation

International Nuclear Information System (INIS)

Choi, Yoon Jung; Lee, Jue Yeon; Lee, Seung Jin; Chung, Chong-Pyoung; Park, Yoon Jeong

2011-01-01

Highlights: ► Doxazocin directly up-regulated bone metabolism at a low dose. ► Doxazocin induced osteoblastic stem cell differentiation without affecting cell proliferation. ► This osteogenic stem cell differentiation is mediated by ERK-signal dependent pathway. -- Abstract: Recent researches have indicated a role for antihypertensive drugs including alpha- or beta-blockers in the prevention of bone loss. Some epidemiological studies reported the protective effects of those agents on fracture risk. However, there is limited information on the association with those agents especially at the mechanism of action. In the present study, we investigated the effects of doxazosin, an alpha-blocker that is clinically used for the treatment of benign prostatic hyperplasia (BPH) along with antihypertensive medication, on the osteogenic stem cell differentiation. We found that doxazosin increased osteogenic differentiation of human mesenchymal stem cells, detected by Alizarin red S staining and calcein. Doxazosin not only induced expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin, it also resulted in increased phosphorylation of extracellular signal-regulated kinase (ERK1/2), a MAP kinase involved in osteoblastic differentiation. Treatment with U0126, a MAP kinase inhibitor, significantly blocked doxazosin-induced osteoblastic differentiation. Unrelated to activation of osteogenic differentiation by doxazosin, we found that there were no significant changes in adipogenic differentiation or in the expression of adipose-specific genes, including peroxisome proliferator-activated receptor γ, aP2, or LPL. In this report, we suggest that doxazosin has the ability to increase osteogenic cell differentiation via ERK1/2 activation in osteogenic differentiation of adult stem cells, which supports the protective effects of antihypertensive drug on fracture risk and according to our data doxazosin might be useful for application in the field of bone

Water soluble bioactives of nacre mediate antioxidant activity and osteoblast differentiation.

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Ratna Chaturvedi

Full Text Available The water soluble matrix of nacre is a proven osteoinductive material. In spite of the differences in the biomolecular compositions of nacre obtained from multiple species of oysters, the common biochemical properties of those principles substantiate their biological activity. However, the mechanism by which nacre stimulates bone differentiation remains largely unknown. Since the positive impact of antioxidants on bone metabolism is well acknowledged, in this study we investigated the antioxidant potential of a water soluble matrix (WSM obtained from the nacre of the marine oyster Pinctada fucata, which could regulate its osteoblast differentiation activity. Enhanced levels of ALP activity observed in pre-osteoblast cells upon treatment with WSM, suggested the induction of bone differentiation events. Furthermore, bone nodule formation and up-regulation of bone differentiation marker transcripts, i.e. collagen type-1 and osteocalcin by WSM confirmed its ability to induce differentiation of the pre-osteoblasts into mature osteoblasts. Remarkably, same WSM fraction upon pre-treatment lowered the H2O2 and UV-B induced oxidative damages in keratinocytes, thus indicating the antioxidant potential of WSM. This was further confirmed from the in vitro scavenging of ABTS and DPPH free radicals and inhibition of lipid peroxidation by WSM. Together, these results indicate that WSM poses both antioxidant potential and osteoblast differentiation property. Thus, bioactivities associated with nacre holds potential in the development of therapeutics for bone regeneration and against oxidative stress induced damages in cells.

Dysregulated gene expression in the primary osteoblasts and osteocytes isolated from hypophosphatemic Hyp mice.

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Kazuaki Miyagawa

Full Text Available Osteocytes express multiple genes involved in mineral metabolism including PHEX, FGF23, DMP1 and FAM20C. In Hyp mice, a murine model for X-linked hypophosphatemia (XLH, Phex deficiency results in the overproduction of FGF23 in osteocytes, which leads to hypophosphatemia and impaired vitamin D metabolism. In this study, to further clarify the abnormality in osteocytes of Hyp mice, we obtained detailed gene expression profiles in osteoblasts and osteocytes isolated from the long bones of 20-week-old Hyp mice and wild-type (WT control mice. The expression of Fgf23, Dmp1, and Fam20c was higher in osteocytic cells than in osteoblastic cells in both genotypes, and was up-regulated in Hyp cells. Interestingly, the up-regulation of these genes in Hyp bones began before birth. On the other hand, the expression of Slc20a1 encoding the sodium/phosphate (Na+/Pi co-transporter Pit1 was increased in osteoblasts and osteocytes from adult Hyp mice, but not in Hyp fetal bones. The direct effects of extracellular Pi and 1,25-dihydroxyvitamin D3 [1,25(OH2D3] on isolated osteoblastic and osteocytic cells were also investigated. Twenty-four-hour treatment with 10-8 M 1,25(OH2D3 increased the expression of Fgf23 in WT osteoblastic cells but not in osteocytic cells. Dmp1 expression in osteocytic cells was increased due to the 24-hour treatment with 10 mM Pi and was suppressed by 10-8 M 1,25(OH2D3 in WT osteocytic cells. We also found the up-regulation of the genes for FGF1, FGF2, their receptors, and Egr-1 which is a target of FGF signaling, in Hyp osteocytic cells, suggesting the activation of FGF/FGFR signaling. These results implicate the complex gene dysregulation in osteoblasts and osteocytes of Hyp mice, which might contribute to the pathogenesis.

Adipose energy stores, physical work, and the metabolic syndrome: lessons from hummingbirds

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Hargrove, James L

2005-01-01

Abstract Hummingbirds and other nectar-feeding, migratory birds possess unusual adaptive traits that offer important lessons concerning obesity, diabetes and the metabolic syndrome. Hummingbirds consume a high sugar diet and have fasting glucose levels that would be severely hyperglycemic in humans, yet these nectar-fed birds recover most glucose that is filtered into the urine. Hummingbirds accumulate over 40% body fat shortly before migrations in the spring and autumn. Despite hyperglycemia...

Peroxisomes in Different Skeletal Cell Types during Intramembranous and Endochondral Ossification and Their Regulation during Osteoblast Differentiation by Distinct Peroxisome Proliferator-Activated Receptors.

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Guofeng Qian

Full Text Available Ossification defects leading to craniofacial dysmorphism or rhizomelia are typical phenotypes in patients and corresponding knockout mouse models with distinct peroxisomal disorders. Despite these obvious skeletal pathologies, to date no careful analysis exists on the distribution and function of peroxisomes in skeletal tissues and their alterations during ossification. Therefore, we analyzed the peroxisomal compartment in different cell types of mouse cartilage and bone as well as in primary cultures of calvarial osteoblasts. The peroxisome number and metabolism strongly increased in chondrocytes during endochondral ossification from the reserve to the hypertrophic zone, whereas in bone, metabolically active osteoblasts contained a higher numerical abundance of this organelle than osteocytes. The high abundance of peroxisomes in these skeletal cell types is reflected by high levels of Pex11β gene expression. During culture, calvarial pre-osteoblasts differentiated into secretory osteoblasts accompanied by peroxisome proliferation and increased levels of peroxisomal genes and proteins. Since many peroxisomal genes contain a PPAR-responsive element, we analyzed the gene expression of PPARɑ/ß/ɣ in calvarial osteoblasts and MC3T3-E1 cells, revealing higher levels for PPARß than for PPARɑ and PPARɣ. Treatment with different PPAR agonists and antagonists not only changed the peroxisomal compartment and associated gene expression, but also induced complex alterations of the gene expression patterns of the other PPAR family members. Studies in M3CT3-E1 cells showed that the PPARß agonist GW0742 activated the PPRE-mediated luciferase expression and up-regulated peroxisomal gene transcription (Pex11, Pex13, Pex14, Acox1 and Cat, whereas the PPARß antagonist GSK0660 led to repression of the PPRE and a decrease of the corresponding mRNA levels. In the same way, treatment of calvarial osteoblasts with GW0742 increased in peroxisome number and

Short time administration of antirheumatic drugs - Methotrexate as a strong inhibitor of osteoblast's proliferation in vitro

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Annussek Tobias

2012-09-01

Full Text Available Abstract Introduction Due to increasing use of disease modifying antirheumatic drugs (DMARDs as first line therapy in rheumatic diseases, dental and maxillofacial practitioner should be aware of drug related adverse events. Especially effects on bone-metabolism and its cells are discussed controversially. Therefore we investigate the in vitro effect of short time administration of low dose methotrexate (MTX on osteoblasts as essential part of bone remodelling cells. Methods Primary bovine osteoblasts (OBs were incubated with various concentrations of MTX, related to tissue concentrations, over a period of fourteen days by using a previously established standard protocol. The effect on cell proliferation as well as mitochondrial activity was assessed by using 3-(4, 5-dimethylthiazol-2-yl 2, 5-diphenyltetrazolium bromide (MTT assay, imaging and counting of living cells. Additionally, immunostaining of extracellular matrix proteins was used to survey osteogenic differentiation. Results All methods indicate a strong inhibition of osteoblast`s proliferation by short time administration of low dose MTX within therapeutically relevant concentrations of 1 to 1000nM, without affecting cell differentiation of middle-stage differentiated OBs in general. More over a significant decrease of cell numbers and mitochondrial activity was found at these MTX concentrations. The most sensitive method seems to be the MTT-assay. MTX-concentration of 0,01nM and concentrations below had no inhibitory effects anymore. Conclusion Even low dose methotrexate acts as a potent inhibitor of osteoblast’s proliferation and mitochondrial metabolism in vitro, without affecting main differentiation of pre-differentiated osteoblasts. These results suggest possible negative effects of DMARDs concerning bone healing and for example osseointegration of dental implants. Especially the specifics of the jaw bone with its high vascularisation and physiological high tissue metabolism

Osteoblast role in osteoarthritis pathogenesis.

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Maruotti, Nicola; Corrado, Addolorata; Cantatore, Francesco P

2017-11-01

Even if osteoarthritis pathogenesis is still poorly understood, numerous evidences suggest that osteoblasts dysregulation plays a key role in osteoarthritis pathogenesis. An abnormal expression of OPG and RANKL has been described in osteoarthritis osteoblasts, which is responsible for abnormal bone remodeling and decreased mineralization. Alterations in genes expression are involved in dysregulation of osteoblast function, bone remodeling, and mineralization, leading to osteoarthritis development. Moreover, osteoblasts produce numerous transcription factors, growth factors, and other proteic molecules which are involved in osteoarthritis pathogenesis. © 2017 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

Extracellular Vesicles from Adipose-Derived Mesenchymal Stem Cells Downregulate Senescence Features in Osteoarthritic Osteoblasts

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Miguel Tofiño-Vian

2017-01-01

Full Text Available Osteoarthritis (OA affects all articular tissues leading to pain and disability. The dysregulation of bone metabolism may contribute to the progression of this condition. Adipose-derived mesenchymal stem cells (ASC are attractive candidates in the search of novel strategies for OA treatment and exert anti-inflammatory and cytoprotective effects on cartilage. Chronic inflammation in OA is a relevant factor in the development of cellular senescence and joint degradation. In this study, we extend our previous observations of ASC paracrine effects to study the influence of conditioned medium and extracellular vesicles from ASC on senescence induced by inflammatory stress in OA osteoblasts. Our results in cells stimulated with interleukin- (IL- 1β indicate that conditioned medium, microvesicles, and exosomes from ASC downregulate senescence-associated β-galactosidase activity and the accumulation of γH2AX foci. In addition, they reduced the production of inflammatory mediators, with the highest effect on IL-6 and prostaglandin E2. The control of mitochondrial membrane alterations and oxidative stress may provide a mechanism for the protective effects of ASC in OA osteoblasts. We have also shown that microvesicles and exosomes mediate the paracrine effects of ASC. Our study suggests that correction of abnormal osteoblast metabolism by ASC products may contribute to their protective effects.

Effects of imatinib and nilotinib on the whole transcriptome of cultured murine osteoblasts.

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Kirschner, Gyöngyi; Balla, Bernadett; Horváth, Péter; Kövesdi, Andrea; Lakatos, Gergely; Takács, István; Nagy, Zsolt; Tóbiás, Bálint; Árvai, Kristóf; Kósa, János Pál; Lakatos, Péter

2016-09-01

Numerous clinical observations have confirmed that breakpoint cluster region-abelson fusion oncoprotein tyrosine kinase inhibitors used in leukemia treatment alter bone physiology in a complex manner. The aim of the present study was to analyze the whole transcriptome of cultured murine osteoblasts and determine the changes following treatment with imatinib and nilotinib using Sequencing by Oligonucleotide Ligation and Detection next generation RNA sequencing. This study also aimed to identify candidate signaling pathways and network regulators by multivariate Ingenuity Pathway Analysis. Based on the right-tailed Fisher's exact test, significantly altered pathways including upstream regulators were defined for each drug. The correlation between these pathways and bone metabolism was also examined. The preliminary results suggest the two drugs have different mechanisms of action on osteoblasts, and imatinib was shown to have a greater effect on gene expression. Data also indicated the potential role of a number of genes and signaling cascades that may contribute to identifying novel targets for the treatment of metabolic bone diseases.

Osteoblast-specific transcription factor Osterix increases vitamin D receptor gene expression in osteoblasts.

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Chi Zhang

Full Text Available Osterix (Osx is an osteoblast-specific transcription factor required for osteoblast differentiation from mesenchymal stem cells. In Osx knock-out mice, no bone formation occurs. The vitamin D receptor (VDR is a member of the nuclear hormone receptor superfamily that regulates target gene transcription to ensure appropriate control of calcium homeostasis and bone development. Here, we provide several lines of evidence that show that the VDR gene is a target for transcriptional regulation by Osx in osteoblasts. For example, calvaria obtained from Osx-null embryos displayed dramatic reductions in VDR expression compared to wild-type calvaria. Stable overexpression of Osx stimulated VDR expression in C2C12 mesenchymal cells. Inhibition of Osx expression by siRNA led to downregulation of VDR. In contrast, Osx levels remained unchanged in osteoblasts in VDR-null mice. Mechanistic approaches using transient transfection assays showed that Osx directly activated a 1 kb fragment of the VDR promoter in a dose-dependent manner. To define the region of the VDR promoter that was responsive to Osx, a series of VDR promoter deletion mutants were examined and the minimal Osx-responsive region was refined to the proximal 120 bp of the VDR promoter. Additional point mutants were used to identify two GC-rich regions that were responsible for VDR promoter activation by Osx. Chromatin immunoprecipitation assays demonstrated that endogenous Osx was associated with the native VDR promoter in primary osteoblasts in vivo. Cumulatively, these data strongly support a direct regulatory role for Osx in VDR gene expression. They further provide new insight into potential mechanisms and pathways that Osx controls in osteoblasts and during the process of osteoblastic cell differentiation.

Osteoblastic cells: differentiation and trans-differentiation

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Kassem, Moustapha; Abdallah, Basem; Saeed, Hamid

2008-01-01

The osteoblast is the bone forming cell and is derived from mesenchymal stem cells (MSC) present among the bone marrow stroma. MSC are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts and adipocytes. Understanding the mechanisms underlying osteoblast different...

Estrogen/ERα signaling axis participates in osteoblast maturation via upregulating chromosomal and mitochondrial complex gene expressions

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Lin, Pei-I; Tai, Yu-Ting; Chan, Wing P.; Lin, Yi-Ling; Liao, Mei-Hsiu; Chen, Ruei-Ming

2018-01-01

Estrogen deficiency usually leads to bone loss and osteoporosis in postmenopausal women. Osteoblasts play crucial roles in bone formation. However, osteoblast functions are influenced by mitochondrial bioenergetic conditions. In this study, we investigated the roles of the estrogen and estrogen receptor alpha (ERα) axis in mitochondrial energy metabolism and subsequent osteoblast mineralization. Exposure of rat calvarial osteoblasts to estradiol caused substantial improvements in alkaline phosphatase activities and cell calcification. In parallel, treatment of human osteoblast-like U2OS cells, derived from a female osteosarcoma patient, with estradiol specifically augmented ERα levels. Sequentially, estradiol stimulated translocation of ERα to nuclei in human osteoblasts and induced expressions of genomic respiratory chain complex NDUFA10, UQCRC1, cytochrome c oxidase (COX)8A, COX6A2, COX8C, COX6C, COX6B2, COX412, and ATP12A genes. Concurrently, estradiol stimulated translocation of ERα to mitochondria from the cytoplasm. A bioinformatic search found the existence of four estrogen response elements in the 5’-promoter region of the mitochondrial cox i gene. Interestingly, estradiol induced COX I mRNA and protein expressions in human osteoblasts or rat calvarial osteoblasts. Knocking-down ERα translation concurrently downregulated estradiol-induced COX I mRNA expression. Consequently, exposure to estradiol led to successive increases in the mitochondrial membrane potential, the mitochondrial enzyme activity, and cellular adenosine triphosphate levels. Taken together, this study showed the roles of the estradiol/ERα signaling axis in improving osteoblast maturation through upregulating the mitochondrial bioenergetic system due to induction of definite chromosomal and mitochondrial complex gene expressions. Our results provide novel insights elucidating the roles of the estrogen/ERα alliance in regulating bone formation. PMID:29416685

MiR-637 maintains the balance between adipocytes and osteoblasts by directly targeting Osterix.

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Zhang, Jin-fang; Fu, Wei-ming; He, Ming-liang; Wang, Hua; Wang, Wei-mao; Yu, Shi-cang; Bian, Xiu-Wu; Zhou, Jin; Lin, Marie C M; Lu, Gang; Poon, Wai-sang; Kung, Hsiang-fu

2011-11-01

Bone development is dynamically regulated by homeostasis, in which a balance between adipocytes and osteoblasts is maintained. Disruption of this differentiation balance leads to various bone-related metabolic diseases, including osteoporosis. In the present study, a primate-specific microRNA (miR-637) was found to be involved in the differentiation of human mesenchymal stem cells (hMSCs). Our preliminary data indicated that miR-637 suppressed the growth of hMSCs and induced S-phase arrest. Expression of miR-637 was increased during adipocyte differentiation (AD), whereas it was decreased during osteoblast differentiation (OS), which suggests miR-637 could act as a mediator of adipoosteogenic differentiation. Osterix (Osx), a significant transcription factor of osteoblasts, was shown to be a direct target of miR-637, which significantly enhanced AD and suppressed OS in hMSCs through direct suppression of Osx expression. Furthermore, miR-637 also significantly enhanced de novo adipogenesis in nude mice. In conclusion, our data indicated that the expression of miR-637 was indispensable for maintaining the balance of adipocytes and osteoblasts. Disruption of miR-637 expression patterns leads to irreversible damage to the balance of differentiation in bone marrow.

Omentin-1 Stimulates Human Osteoblast Proliferation through PI3K/Akt Signal Pathway

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Shan-Shan Wu

2013-01-01

Full Text Available It has been presumed that adipokines deriving from adipose tissue may play important roles in bone metabolism. Omentin-1, a novel adipokine, which is selectively expressed in visceral adipose tissue, has been reported to stimulate proliferation and inhibit differentiation of mouse osteoblast. However, little information refers to the effect of omentin-1 on human osteoblast (hOB proliferation. The current study examined the potential effects of omentin-1 on proliferation in hOB and the signal pathway involved. Omentin-1 promoted hOB proliferation in a dose-dependent manner as determined by [3H]thymidine incorporation. Western blot analysis revealed that omentin-1 induced activation of Akt (phosphatidylinositol-3 kinase downstream effector and such effect was impeded by transfection of hOB with Akt-siRNA. Furthermore, LY294002 (a selective PI3K inhibitor and HIMO (a selective Akt inhibitor abolished the omentin-1-induced hOB proliferation. These findings indicate that omentin-1 induces hOB proliferation via the PI3K/Akt signaling pathway and suggest that osteoblast is a direct target of omentin-1.

Physical activity and hypocaloric diet recovers osteoblasts homeostasis in women affected by abdominal obesity.

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Bimonte, Viviana M; Fittipaldi, Simona; Marocco, Chiara; Emerenziani, Gian Pietro; Fornari, Rachele; Guidetti, Laura; Poggiogalle, Eleonora; Nicolai, Emanuele; Di Luigi, Luigi; Donini, Lorenzo M; Baldari, Carlo; Lenzi, Andrea; Greco, Emanuela A; Migliaccio, Silvia

2017-11-01

Obesity is a multifactorial disease linked to metabolic chronic disorders such as diabetes, and hypertension. Also, it has recently been associated with skeletal alterations and low bone mineral density. We previously demonstrated that exposure of osteoblasts to sera of sedentary subjects affected by obesity alters cell homeostasis in vitro, leading to disruption of intracellular differentiation pathways and cellular activity. Thus, the purpose of the present study has been to evaluate whether sera of sedentary obese women, subjected to physical activity and hypocaloric diet, could recover osteoblast homeostasis in vitro as compared to the sera of same patients before intervention protocol. To this aim, obese women were evaluated at time 0 and after 4, 6, and 12 months of individualized prescribed physical activity and hypocaloric diet. Dual-energy-X-ray absorptiometry measurements were performed at each time point, as well as blood was collected at the same points. Cells were incubated with sera of subjects before and after physical activity as described: obese at baseline and after for 4, 6, and 12 months of physical activity and nutritional protocol intervention. Osteoblasts exposed to sera of patients, who displayed increased lean and decreased fat mass (from 55.5 ± 6.5 to 57.1 ± 5.6% p ≤ 0.05; from 44.5 ± 1.1 to 40.9 ± 2.6% p ≤ 0.01 respectively), showed a time-dependent increase of Wnt/β-catenin signaling, versus cells exposed to sera of obese patients before intervention protocol, suggesting recovery of osteoblast homeostasis upon improvement of body composition. An increase in β-catenin nuclear accumulation and nuclear translocation was also observed, accompanied by an increase in Adiponectin receptor 1 protein expression, suggesting positive effect on cell differentiation program. Furthermore, a decrease in sclerostin amount and an increase of type 1 procollagen amino-terminal-propeptide were depicted as compared to

Palmitic Acid Reduces Circulating Bone Formation Markers in Obese Animals and Impairs Osteoblast Activity via C16-Ceramide Accumulation.

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Alsahli, Ahmad; Kiefhaber, Kathryn; Gold, Tziporah; Muluke, Munira; Jiang, Hongfeng; Cremers, Serge; Schulze-Späte, Ulrike

2016-05-01

Obesity and impaired lipid metabolism increase circulating and local fatty acid (FA) levels. Our previous studies showed that a high high-saturated -fat diet induced greater bone loss in mice than a high high-unsaturated-fat diet due to increased osteoclast numbers and activity. The impact of elevated FA levels on osteoblasts is not yet clear. We induced obesity in 4 week old male mice using a palmitic acid (PA)- or oleic acid (OA)-enriched high fat high-fat diet (HFD) (20 % of calories from FA), and compared them to mice on a normal (R) caloric diet (10 % of calories from FA). We collected serum to determine FA and bone metabolism marker levels. Primary osteoblasts were isolated; cultured in PA, OA, or control (C) medium; and assessed for mineralization activity, gene expression, and ceramide levels. Obese animals in the PA and OA groups had significantly lower serum levels of bone formation markers P1NP and OC compared to normal weight animals (*p < 0.001), with the lowest marker levels in animals on an PA-enriched HFD (*p < 0.001). Accordingly, elevated levels of PA significantly reduced osteoblast mineralization activity in vitro (*p < 0.05). Elevated PA intake significantly increased C16 ceramide accumulation. This accumulation was preventable through inhibition of SPT2 (serine palmitoyl transferase 2) using myriocin. Elevated levels of PA reduce osteoblast function in vitro and bone formation markers in vivo. Our findings suggest that saturated PA can compromise bone health by affecting osteoblasts, and identify a potential mechanism through which obesity promotes bone loss.

Impaired osteoblast function in osteoporosis: comparison between calcium balance and dynamic histomorphometry.

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Arlot, M; Edouard, C; Meunier, P J; Neer, R M; Reeve, J

1984-09-01

Osteoblast function was investigated in 27 patients with idiopathic osteoporosis. Transiliac bone biopsy specimens were taken after double labelling with tetracycline, and metabolic calcium balance was studied almost simultaneously. Many of the patients showed poor double labelling of their otherwise unremarkable trabecular osteoid, suggesting impaired formation of bone at many of these surfaces. This phenomenon was not accompanied by increased width of osteoid seams (as seen in osteomalacia), indicating that formation of the matrix and its mineralisation were in equilibrium. For the first time, highly significant positive correlations (p less than 0.01) were found between indices of bone formation, determined by labelling with tetracycline, and calcium balance. Thus some patients with osteoporosis who are rapidly losing bone have low rates of formation of trabecular bone both by individual osteoblasts and in relation to available bone surfaces. As histological indices of bone resorption also independently correlated strongly and inversely (p less than 0.01) with calcium balance the rate of initiation of new basic multicellular units by osteoclastic resorption of trabecular surfaces (or the depth of resorption at these surfaces) also appears to be an important determinant of mineral balance. The mechanisms that regulate the effective life span of mature osteoblasts require further investigation, particularly as some promising treatments that can increase trabecular bone volume in osteoporosis, such as parathyroid peptide hPTH (1-34) and sodium fluoride, must work through a reversal of osteoblastic depression.

Serotonin regulates osteoblast proliferation and function in vitro

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Dai, S.Q.; Yu, L.P. [Department of Orthopedic Surgery, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu (China); Shi, X. [Department of Obstetrics and Gynecology, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu (China); Wu, H. [Emergency Department, The First Affiliated Hospital, Soochow University, Suzhou (China); Shao, P.; Yin, G.Y.; Wei, Y.Z. [Department of Orthopedic Surgery, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu (China)

2014-08-01

The monoamine serotonin (5-hydroxytryptamine, 5-HT), a well-known neurotransmitter, also has important functions outside the central nervous system. The objective of this study was to investigate the role of 5-HT in the proliferation, differentiation, and function of osteoblasts in vitro. We treated rat primary calvarial osteoblasts with various concentrations of 5-HT (1 nM to 10 µM) and assessed the rate of osteoblast proliferation, expression levels of osteoblast-specific proteins and genes, and the ability to form mineralized nodules. Next, we detected which 5-HT receptor subtypes were expressed in rat osteoblasts at different stages of osteoblast differentiation. We found that 5-HT could inhibit osteoblast proliferation, differentiation, and mineralization at low concentrations, but this inhibitory effect was mitigated at relatively high concentrations. Six of the 5-HT receptor subtypes (5-HT{sub 1A}, 5-HT{sub 1B}, 5-HT{sub 1D}, 5-HT{sub 2A}, 5-HT{sub 2B}, and 5-HT{sub 2C}) were found to exist in rat osteoblasts. Of these, 5-HT{sub 2A} and 5-HT{sub 1B} receptors had the highest expression levels, at both early and late stages of differentiation. Our results indicated that 5-HT can regulate osteoblast proliferation and function in vitro.

Ginsenoside Re Promotes Osteoblast Differentiation in Mouse Osteoblast Precursor MC3T3-E1 Cells and a Zebrafish Model

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Hye-Min Kim

2016-12-01

Full Text Available Bone homeostasis is tightly regulated to balance bone formation and bone resorption. Many anabolic drugs are used as bone-targeted therapeutic agents for the promotion of osteoblast-mediated bone formation or inhibition of osteoclast-mediated bone resorption. Previous studies showed that ginsenoside Re has the effect of the suppression of osteoclast differentiation in mouse bone-marrow derived macrophages and zebrafish. Herein, we investigated whether ginsenoside Re affects osteoblast differentiation and mineralization in in vitro and in vivo models. Mouse osteoblast precursor MC3T3-E1 cells were used to investigate cell viability, alkaline phosphatase (ALP activity, and mineralization. In addition, we examined osteoblastic signaling pathways. Ginsenoside Re affected ALP activity without cytotoxicity, and we also observed the stimulation of osteoblast differentiation through the activation of osteoblast markers including runt-related transcription factor 2, type 1 collagen, ALP, and osteocalcin in MC3T3-E1 cells. Moreover, Alizarin red S staining indicated that ginsenoside Re increased osteoblast mineralization in MC3T3-E1 cells and zebrafish scales compared to controls. These results suggest that ginsenoside Re promotes osteoblast differentiation as well as inhibits osteoclast differentiation, and it could be a potential therapeutic agent for bone diseases.

Impaired osteoblast function in osteoporosis: comparison between calcium balance and dynamic histomorphometry.

OpenAIRE

Arlot, M; Edouard, C; Meunier, P J; Neer, R M; Reeve, J

1984-01-01

Osteoblast function was investigated in 27 patients with idiopathic osteoporosis. Transiliac bone biopsy specimens were taken after double labelling with tetracycline, and metabolic calcium balance was studied almost simultaneously. Many of the patients showed poor double labelling of their otherwise unremarkable trabecular osteoid, suggesting impaired formation of bone at many of these surfaces. This phenomenon was not accompanied by increased width of osteoid seams (as seen in osteomalacia)...

Dual Effect of Chrysanthemum indicum Extract to Stimulate Osteoblast Differentiation and Inhibit Osteoclast Formation and Resorption In Vitro

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Jong Min Baek

2014-01-01

Full Text Available The risk of bone-related diseases increases due to the imbalance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively. The goal in the development of antiosteoporotic treatments is an agent that will improve bone through simultaneous osteoblast stimulation and osteoclast inhibition without undesirable side effects. To achieve this goal, numerous studies have been performed to identify novel approaches using natural oriental herbs to treat bone metabolic diseases. In the present study, we investigated the effect of Chrysanthemum indicum extract (CIE on the differentiation of osteoclastic and osteoblastic cells. CIE inhibited the formation of TRAP-positive mature osteoclasts and of filamentous-actin rings and disrupted the bone-resorbing activity of mature osteoclasts in a dose-dependent manner. CIE strongly inhibited Akt, GSK3β, and IκB phosphorylation in RANKL-stimulated bone marrow macrophages and did not show any effects on MAP kinases, including p38, ERK, and JNK. Interestingly, CIE also enhanced primary osteoblast differentiation via upregulation of the expression of alkaline phosphatase and the level of extracellular calcium concentrations during the early and terminal stages of differentiation, respectively. Our results revealed that CIE could have a potential therapeutic role in bone-related disorders through its dual effects on osteoclast and osteoblast differentiation.

Transcriptional Regulation of Frizzled-1 in Human Osteoblasts by Sp1.

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Shibing Yu

Full Text Available The wingless pathway has a powerful influence on bone metabolism and is a therapeutic target in skeletal disorders. Wingless signaling is mediated in part through the Frizzled (FZD receptor family. FZD transcriptional regulation is poorly understood. Herein we tested the hypothesis that Sp1 plays an important role in the transcriptional regulation of FZD1 expression in osteoblasts and osteoblast mineralization. To test this hypothesis, we conducted FZD1 promoter assays in Saos2 cells with and without Sp1 overexpression. We found that Sp1 significantly up-regulates FZD1 promoter activity in Saos2 cells. Chromatin immunoprecipitation (ChIP and electrophoretic mobility shift (EMSA assays identified a novel and functional Sp1 binding site at -44 to -40 from the translation start site in the FZD1 promoter. The Sp1-dependent activation of the FZD1 promoter was abolished by mithramycin A (MMA, an antibiotic affecting both Sp1 binding and Sp1 protein levels in Saos2 cells. Similarly, down-regulation of Sp1 in hFOB cells resulted in less FZD1 expression and lower alkaline phosphatase activity. Moreover, over-expression of Sp1 increased FZD1 expression and Saos2 cell mineralization while MMA decreased Sp1 and FZD1 expression and Saos2 cell mineralization. Knockdown of FZD1 prior to Sp1 overexpression partially abolished Sp1 stimulation of osteoblast differentiation markers. Taken together, our results suggest that Sp1 plays a role in human osteoblast differentiation and mineralization, which is at least partially mediated by Sp1-dependent transactivation of FZD1.

Inhibition of prostate cancer osteoblastic progression with VEGF121/rGel, a single agent targeting osteoblasts, osteoclasts, and tumor neovasculature.

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Mohamedali, Khalid A; Li, Zhi Gang; Starbuck, Michael W; Wan, Xinhai; Yang, Jun; Kim, Sehoon; Zhang, Wendy; Rosenblum, Michael G; Navone, Nora M

2011-04-15

A hallmark of prostate cancer (PCa) progression is the development of osteoblastic bone metastases, which respond poorly to available therapies. We previously reported that VEGF(121)/rGel targets osteoclast precursors and tumor neovasculature. Here we tested the hypothesis that targeting nontumor cells expressing these receptors can inhibit tumor progression in a clinically relevant model of osteoblastic PCa. Cells from MDA PCa 118b, a PCa xenograft obtained from a bone metastasis in a patient with castrate-resistant PCa, were injected into the femurs of mice. Osteoblastic progression was monitored following systemic administration of VEGF(121)/rGel. VEGF(121)/rGel was cytotoxic in vitro to osteoblast precursor cells. This cytotoxicity was specific as VEGF(121)/rGel internalization into osteoblasts was VEGF(121) receptor driven. Furthermore, VEGF(121)/rGel significantly inhibited PCa-induced bone formation in a mouse calvaria culture assay. In vivo, VEGF(121)/rGel significantly inhibited the osteoblastic progression of PCa cells in the femurs of nude mice. Microcomputed tomographic analysis revealed that VEGF(121)/rGel restored the bone volume fraction of tumor-bearing femurs to values similar to those of the contralateral (non-tumor-bearing) femurs. VEGF(121)/rGel significantly reduced the number of tumor-associated osteoclasts but did not change the numbers of peritumoral osteoblasts. Importantly, VEGF(121)/rGel-treated mice had significantly less tumor burden than control mice. Our results thus indicate that VEGF(121)/rGel inhibits osteoblastic tumor progression by targeting angiogenesis, osteoclastogenesis, and bone formation. Targeting VEGF receptor (VEGFR)-1- or VEGFR-2-expressing cells is effective in controlling the osteoblastic progression of PCa in bone. These findings provide the basis for an effective multitargeted approach for metastatic PCa. ©2011 AACR.

Inhibition of prostate cancer osteoblastic progression with VEGF121/rGel, a single agent targeting osteoblasts, osteoclasts, and tumor neovasculature

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Mohamedali, Khalid A.; Li, Zhi Gang; Starbuck, Michael W.; Wan, Xinhai; Yang, Jun; Kim, Sehoon; Zhang, Wendy; Rosenblum, Michael G.; Navone, Nora M.

2011-01-01

Purpose A hallmark of prostate cancer (PCa) progression is the development of osteoblastic bone metastases, which respond poorly to available therapies. We previously reported that VEGF121/rGel targets osteoclast precursors and tumor neovasculature. Here we tested the hypothesis that targeting non-tumor cells expressing these receptors can inhibit tumor progression in a clinically relevant model of osteoblastic PCa. Experimental Design Cells from MDA PCa 118b, a PCa xenograft obtained from a bone metastasis in a patient with castrate-resistant PCa, were injected into the femurs of mice. Osteoblastic progression was monitored following systemic administration of VEGF121/rGel. Results VEGF121/rGel was cytotoxic in vitro to osteoblast precursor cells. This cytotoxicity was specific as VEGF121/rGel internalization into osteoblasts was VEGF121 receptor driven. Furthermore, VEGF121/rGel significantly inhibited PCa-induced bone formation in a mouse calvaria culture assay. In vivo, VEGF121/rGel significantly inhibited the osteoblastic progression of PCa cells in the femurs of nude mice. Microcomputed tomography analysis revealed that VEGF121/rGel restored the bone volume fraction of tumor-bearing femurs to values similar to those of the contralateral (non–tumor bearing) femurs. VEGF121/rGel significantly reduced the number of tumor-associated osteoclasts but did not change the numbers of peritumoral osteoblasts. Importantly, VEGF121/rGel-treated mice had significantly less tumor burden than control mice. Our results thus indicate that VEGF121/rGel inhibits osteoblastic tumor progression by targeting angiogenesis, osteoclastogenesis, and bone formation. Conclusions Targeting VEGFR-1 – or VEGFR-2–expressing cells is effective in controlling the osteoblastic progression of PCa in bone. These findings provide the basis for an effective multitargeted approach for metastatic PCa. PMID:21343372

Zoledronic acid at subtoxic dose extends osteoblastic stage span of primary human osteoblasts.

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Zara, Susi; De Colli, Marianna; di Giacomo, Viviana; Zizzari, Vincenzo Luca; Di Nisio, Chiara; Di Tore, Umberto; Salini, Vincenzo; Gallorini, Marialucia; Tetè, Stefano; Cataldi, Amelia

2015-04-01

This study aimed to check the effect of zoledronic acid (ZA) at subtoxic dose on human osteoblasts (HOs) in terms of cell viability, apoptosis occurrence, and differentiation induction. ZA belongs to the family of bisphosphonates (BPs), largely used in the clinical practice for the treatment of bone diseases, often associated with jaw osteonecrosis onset. Their pharmacological action consists in the direct block of the osteoclast-mediated bone resorption along with indirect action on osteoblasts. HOs were treated choosing the highest limit concentration (10(-5) M) which does not induce toxic effects. Live/dead staining, flow cytometry, mitochondrial membrane potential assay, osteocalcin western blotting, gp38 RT-PCR, collagen type I, PGE2, and IL-6 ELISA assays were performed. Similar viability level between control and ZA-treated samples is found along with no significant increase of apoptotic and necrotic cells in ZA-treated sample. To establish if an early apoptotic pathway was triggered, Bax expression and mitochondrial membrane potential were evaluated finding a higher protein expression in control sample and a good integrity of mitochondrial membrane in both experimental points. Type I collagen secretion and alkaline phosphatase (ALP) activity appear increased in ZA-treated sample, osteocalcin expression level is reduced in ZA-treated cells, whereas no modifications of gp38 mRNA level are evidenced. No statistical differences are identified in PGE2 secretion level whereas IL-6 secretion is lower in ZA-treated HOs with respect to control ones. These results highlight that ZA, delaying the osteoblastic differentiation process versus the osteocytic lineage, strengthens its pharmacological activity enhancing bone density. The knowledge of ZA effects on osteoblasts at subtoxic dose allows to improve therapeutic protocols in order to strengthen drug pharmacological activity through a combined action on both osteoclastic and osteoblastic cells.

Time-lapse Raman imaging of osteoblast differentiation

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Hashimoto, Aya; Yamaguchi, Yoshinori; Chiu, Liang-Da; Morimoto, Chiaki; Fujita, Katsumasa; Takedachi, Masahide; Kawata, Satoshi; Murakami, Shinya; Tamiya, Eiichi

2015-07-01

Osteoblastic mineralization occurs during the early stages of bone formation. During this mineralization, hydroxyapatite (HA), a major component of bone, is synthesized, generating hard tissue. Many of the mechanisms driving biomineralization remain unclear because the traditional biochemical assays used to investigate them are destructive techniques incompatible with viable cells. To determine the temporal changes in mineralization-related biomolecules at mineralization spots, we performed time-lapse Raman imaging of mouse osteoblasts at a subcellular resolution throughout the mineralization process. Raman imaging enabled us to analyze the dynamics of the related biomolecules at mineralization spots throughout the entire process of mineralization. Here, we stimulated KUSA-A1 cells to differentiate into osteoblasts and conducted time-lapse Raman imaging on them every 4 hours for 24 hours, beginning 5 days after the stimulation. The HA and cytochrome c Raman bands were used as markers for osteoblastic mineralization and apoptosis. From the Raman images successfully acquired throughout the mineralization process, we found that β-carotene acts as a biomarker that indicates the initiation of osteoblastic mineralization. A fluctuation of cytochrome c concentration, which indicates cell apoptosis, was also observed during mineralization. We expect time-lapse Raman imaging to help us to further elucidate osteoblastic mineralization mechanisms that have previously been unobservable.

Mycobacterium leprae downregulates the expression of PHEX in Schwann cells and osteoblasts

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Sandra R Boiça Silva

2010-08-01

Full Text Available Neuropathy and bone deformities, lifelong sequelae of leprosy that persist after treatment, result in significant impairment to patients and compromise their social rehabilitation. Phosphate-regulating gene with homologies to endopeptidase on the X chromosome (PHEX is a Zn-metalloendopeptidase, which is abundantly expressed in osteoblasts and many other cell types, such as Schwann cells, and has been implicated in phosphate metabolism and X-linked rickets. Here, we demonstrate that Mycobacterium leprae stimulation downregulates PHEX transcription and protein expression in a human schwannoma cell line (ST88-14 and human osteoblast lineage. Modulation of PHEX expression was observed to a lesser extent in cells stimulated with other species of mycobacteria, but was not observed in cultures treated with latex beads or with the facultative intracellular bacterium Salmonella typhimurium. Direct downregulation of PHEX by M. leprae could be involved in the bone resorption observed in leprosy patients. This is the first report to describe PHEX modulation by an infectious agent.

The Src inhibitor dasatinib accelerates the differentiation of human bone marrow-derived mesenchymal stromal cells into osteoblasts

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Id Boufker, Hichame; Lagneaux, Laurence; Najar, Mehdi; Piccart, Martine; Ghanem, Ghanem; Body, Jean-Jacques; Journé, Fabrice

2010-01-01

The proto-oncogene Src is an important non-receptor protein tyrosine kinase involved in signaling pathways that control cell adhesion, growth, migration and differentiation. It negatively regulates osteoblast activity, and, as such, its inhibition is a potential means to prevent bone loss. Dasatinib is a new dual Src/Bcr-Abl tyrosine kinase inhibitor initially developed for the treatment of chronic myeloid leukemia. It has also shown promising results in preclinical studies in various solid tumors. However, its effects on the differentiation of human osteoblasts have never been examined. We evaluated the effects of dasatinib on bone marrow-derived mesenchymal stromal cells (MSC) differentiation into osteoblasts, in the presence or absence of a mixture of dexamethasone, ascorbic acid and β-glycerophosphate (DAG) for up to 21 days. The differentiation kinetics was assessed by evaluating mineralization of the extracellular matrix, alkaline phosphatase (ALP) activity, and expression of osteoblastic markers (receptor activator of nuclear factor kappa B ligand [RANKL], bone sialoprotein [BSP], osteopontin [OPN]). Dasatinib significantly increased the activity of ALP and the level of calcium deposition in MSC cultured with DAG after, respectively, 7 and 14 days; it upregulated the expression of BSP and OPN genes independently of DAG; and it markedly downregulated the expression of RANKL gene and protein (decrease in RANKL/OPG ratio), the key factor that stimulates osteoclast differentiation and activity. Our results suggest a dual role for dasatinib in both (i) stimulating osteoblast differentiation leading to a direct increase in bone formation, and (ii) downregulating RANKL synthesis by osteoblasts leading to an indirect inhibition of osteoclastogenesis. Thus, dasatinib is a potentially interesting candidate drug for the treatment of osteolysis through its dual effect on bone metabolism

Bidirectional communication between sensory neurons and osteoblasts in an in vitro coculture system.

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Kodama, Daisuke; Hirai, Takao; Kondo, Hisataka; Hamamura, Kazunori; Togari, Akifumi

2017-02-01

Recent studies have revealed that the sensory nervous system is involved in bone metabolism. However, the mechanism of communication between neurons and osteoblasts is yet to be elucidated. In this study, we investigated the signaling pathways between sensory neurons of the dorsal root ganglion (DRG) and the osteoblast-like MC3T3-E1 cells using an in vitro coculture system. Our findings indicate that signal transduction from DRG-derived neurons to MC3T3-E1 cells is suppressed by antagonists of the AMPA receptor and the NK 1 receptor. Conversely, signal transduction from MC3T3-E1 cells to DRG-derived neurons is suppressed by a P2X 7 receptor antagonist. Our results suggest that these cells communicate with each other by exocytosis of glutamate, substance P in the efferent signal, and ATP in the afferent signal. © 2017 Federation of European Biochemical Societies.

Hedgehog signaling in tumor cells facilitates osteoblast-enhanced osteolytic metastases.

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Shamik Das

Full Text Available The remodeling process in bone yields numerous cytokines and chemokines that mediate crosstalk between osteoblasts and osteoclasts and also serve to attract and support metastatic tumor cells. The metastatic tumor cells disturb the equilibrium in bone that manifests as skeletal complications. The Hedgehog (Hh pathway plays an important role in skeletogenesis. We hypothesized that the Hh pathway mediates an interaction between tumor cells and osteoblasts and influences osteoblast differentiation in response to tumor cells. We have determined that breast tumor cells have an activated Hh pathway characterized by upregulation of the ligand, IHH and transcription factor GLI1. Breast cancer cells interact with osteoblasts and cause an enhanced differentiation of pre-osteoblasts to osteoblasts that express increased levels of the osteoclastogenesis factors, RANKL and PTHrP. There is sustained expression of osteoclast-promoting factors, RANKL and PTHrP, even after the osteoblast differentiation ceases and apoptosis sets in. Moreover, tumor cells that are deficient in Hh signaling are compromised in their ability to induce osteoblast differentiation and consequently are inefficient in causing osteolysis. The stimulation of osteoblast differentiation sets the stage for osteoclast differentiation and overall promotes osteolysis. Thus, in the process of developing newer therapeutic strategies against breast cancer metastasis to bone it would worthwhile to keep in mind the role of the Hh pathway in osteoblast differentiation in an otherwise predominant osteolytic phenomenon.

Therapeutic Doses of Nonsteroidal Anti-Inflammatory Drugs Inhibit Osteosarcoma MG-63 Osteoblast-Like Cells Maturation, Viability, and Biomineralization Potential

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E. De Luna-Bertos

2013-01-01

Full Text Available Nonsteroidal anti-inflammatory drugs (NSAIDs are frequently used to reduce pain and inflammation. However, their effect on bone metabolisms is not well known, and results in the literature are contradictory. The present study focusses on the effect of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid, at therapeutic doses, on different biochemical and phenotypic pathways in human osteoblast-like cells. Osteoblasts (MG-63 cell line were incubated in culture medium with 1–10 μM of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid. Flow cytometry was used to study antigenic profile and phagocytic activity. The osteoblastic differentiation was evaluated by mineralization and synthesis of collagen fibers by microscopy and alkaline phosphatase activity (ALP by spectrophotometric assay. Short-term treatment with therapeutic doses of NSAIDs modulated differentiation, antigenic profile, and phagocyte activity of osteoblast-like cells. The treatment reduced ALP synthesis and matrix mineralization. However, nonsignificant differences were observed on collagen syntheses after treatments. The percentage of CD54 expression was increased with all treatments. CD80, CD86, and HLA-DR showed a decreased expression, which depended on NSAID and the dose applied. The treatments also decreased phagocyte activity in this cellular population. The results of this paper provide evidences that NSAIDs inhibit the osteoblast differentiation process thus reducing their ability to produce new bone mineralized extracellular matrix.

Therapeutic Doses of Nonsteroidal Anti-Inflammatory Drugs Inhibit Osteosarcoma MG-63 Osteoblast-Like Cells Maturation, Viability, and Biomineralization Potential

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De Luna-Bertos, E.; Ramos-Torrecillas, J.; García-Martínez, O.; Guildford, A.; Santin, M.; Ruiz, C.

2013-01-01

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used to reduce pain and inflammation. However, their effect on bone metabolisms is not well known, and results in the literature are contradictory. The present study focusses on the effect of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid, at therapeutic doses, on different biochemical and phenotypic pathways in human osteoblast-like cells. Osteoblasts (MG-63 cell line) were incubated in culture medium with 1–10 μM of dexketoprofen, ketorolac, metamizole, and acetylsalicylic acid. Flow cytometry was used to study antigenic profile and phagocytic activity. The osteoblastic differentiation was evaluated by mineralization and synthesis of collagen fibers by microscopy and alkaline phosphatase activity (ALP) by spectrophotometric assay. Short-term treatment with therapeutic doses of NSAIDs modulated differentiation, antigenic profile, and phagocyte activity of osteoblast-like cells. The treatment reduced ALP synthesis and matrix mineralization. However, nonsignificant differences were observed on collagen syntheses after treatments. The percentage of CD54 expression was increased with all treatments. CD80, CD86, and HLA-DR showed a decreased expression, which depended on NSAID and the dose applied. The treatments also decreased phagocyte activity in this cellular population. The results of this paper provide evidences that NSAIDs inhibit the osteoblast differentiation process thus reducing their ability to produce new bone mineralized extracellular matrix. PMID:24170983

Effects of interfacial micromotions on vitality and differentiation of human osteoblasts.

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Ziebart, J; Fan, S; Schulze, C; Kämmerer, P W; Bader, R; Jonitz-Heincke, A

2018-02-01

Enhanced micromotions between the implant and surrounding bone can impair osseointegration, resulting in fibrous encapsulation and aseptic loosening of the implant. Since the effect of micromotions on human bone cells is sparsely investigated, an in vitro system, which allows application of micromotions on bone cells and subsequent investigation of bone cell activity, was developed. Micromotions ranging from 25 µm to 100 µm were applied as sine or triangle signal with 1 Hz frequency to human osteoblasts seeded on collagen scaffolds. Micromotions were applied for six hours per day over three days. During the micromotions, a static pressure of 527 Pa was exerted on the cells by Ti6Al4V cylinders. Osteoblasts loaded with Ti6Al4V cylinders and unloaded osteoblasts without micromotions served as controls. Subsequently, cell viability, expression of the osteogenic markers collagen type I, alkaline phosphatase, and osteocalcin, as well as gene expression of osteoprotegerin, receptor activator of NF-κB ligand, matrix metalloproteinase-1, and tissue inhibitor of metalloproteinase-1, were investigated. Live and dead cell numbers were higher after 25 µm sine and 50 µm triangle micromotions compared with loaded controls. Collagen type I synthesis was downregulated in respective samples. The metabolic activity and osteocalcin expression level were higher in samples treated with 25 µm micromotions compared with the loaded controls. Furthermore, static loading and micromotions decreased the osteoprotegerin/receptor activator of NF-κB ligand ratio. Our system enables investigation of the behaviour of bone cells at the bone-implant interface under shear stress induced by micromotions. We could demonstrate that micromotions applied under static pressure conditions have a significant impact on the activity of osteoblasts seeded on collagen scaffolds. In future studies, higher mechanical stress will be applied and different implant surface structures will be

Tridax procumbens flavonoids promote osteoblast differentiation and bone formation

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Md. Abdullah Al Mamun

Full Text Available BACKGROUND: Tridaxprocumbens flavonoids (TPFs are well known for their medicinal properties among local natives. Besides traditionally used for dropsy, anemia, arthritis, gout, asthma, ulcer, piles, and urinary problems, it is also used in treating gastric problems, body pain, and rheumatic pains of joints. TPFs have been reported to increase osteogenic functioning in mesenchymal stem cells. Our previous study showed that TPFs were significantly suppressed the RANKL-induced differentiation of osteoclasts and bone resorption. However, the effects of TPFs to promote osteoblasts differentiation and bone formation remain unclear. TPFs were isolated from Tridax procumbens and investigated for their effects on osteoblasts differentiation and bone formation by using primary mouse calvarial osteoblasts RESULTS: TPFs promoted osteoblast differentiation in a dose-dependent manner demonstrated by up-regulation of alkaline phosphatase and osteocalcin. TPFs also upregulated osteoblast differentiation related genes, including osteocalcin, osterix, and Runx2 in primary osteoblasts. TPFs treated primary osteoblast cells showed significant upregulation of bone morphogenetic proteins (BMPs including Bmp-2, Bmp-4, and Bmp-7. Addition of noggin, a BMP specific-antagonist, inhibited TPFs induced upregulation of the osteocalcin, osterix, and Runx2 CONCLUSION: Our findings point towards the induction of osteoblast differentiation by TPFs and suggested that TPFs could be a potential anabolic agent to treat patients with bone loss-associated diseases such as osteoporosis

The effect of a new direct Factor Xa inhibitor on human osteoblasts: an in-vitro study comparing the effect of rivaroxaban with enoxaparin

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Solayar, Gandhi N

2011-10-28

Abstract Background Current treatments for the prevention of thromboembolism include heparin and low-molecular weight heparins (LMWHs). A number of studies have suggested that long term administration of these drugs may adversely affect osteoblasts and therefore, bone metabolism. Xarelto™ (Rivaroxaban) is a new anti-thrombotic drug for the prevention of venous thromboembolism in adult patients undergoing elective hip and knee replacement surgery. The aim of this in vitro study was to investigate the possible effects of rivaroxaban on osteoblast viability, function and gene expression compared to enoxaparin, a commonly used LMWH. Methods Primary human osteoblast cultures were treated with varying concentrations of rivaroxaban (0.013, 0.13, 1.3 and 13 μg\\/ml) or enoxaparin (1, 10 and 100 μg\\/ml). The effect of each drug on osteoblast function was evaluated by measuring alkaline phosphatase activity. The MTS assay was used to assess the effect of drug treatments on cell proliferation. Changes in osteocalcin, Runx2 and BMP-2 messenger RNA (mRNA) expression following drug treatments were measured by real-time polymerase chain reaction (PCR). Results Rivaroxaban and enoxaparin treatment did not adversely affect osteoblast viability. However, both drugs caused a significant reduction in osteoblast function, as measured by alkaline phosphatase activity. This reduction in osteoblast function was associated with a reduction in the mRNA expression of the bone marker, osteocalcin, the transcription factor, Runx2, and the osteogenic factor, BMP-2. Conclusions These data show that rivaroxaban treatment may negatively affect bone through a reduction in osteoblast function.

Nanoceramics on osteoblast proliferation and differentiation in bone tissue engineering.

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Sethu, Sai Nievethitha; Namashivayam, Subhapradha; Devendran, Saravanan; Nagarajan, Selvamurugan; Tsai, Wei-Bor; Narashiman, Srinivasan; Ramachandran, Murugesan; Ambigapathi, Moorthi

2017-05-01

Bone, a highly dynamic connective tissue, consist of a bioorganic phase comprising osteogenic cells and proteins which lies over an inorganic phase predominantly made of CaPO 4 (biological apatite). Injury to bone can be due to mechanical, metabolic or inflammatory agents also owing pathological conditions like fractures, osteomyelitis, osteolysis or cysts may arise in enameloid, chondroid, cementum, or chondroid bone which forms the intermediate tissues of the body. Bone tissue engineering (BTE) applies bioactive scaffolds, host cells and osteogenic signals for restoring damaged or diseased tissues. Various bioceramics used in BTE can be bioactive (like glass ceramics and hydroxyapatite bioactive glass), bioresorbable (like tricalcium phosphates) or bioinert (like zirconia and alumina). Limiting the size of these materials to nano-scale has resulted in a higher surface area to volume ratio thereby improving multi-functionality, solubility, surface catalytic activity, high heat and electrical conductivity. Nanoceramics have been found to induce osteoconduction, osteointegration, osteogenesis and osteoinduction. The present review aims at summarizing the interactions of nanoceramics and osteoblast/stem cells for promoting the proliferation and differentiation of the osteoblast cells by nanoceramics as superior bone substitutes in bone tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Building strong bones: molecular regulation of the osteoblast lineage.

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Long, Fanxin

2011-12-22

The past 15 years have witnessed tremendous progress in the molecular understanding of osteoblasts, the main bone-forming cells in the vertebrate skeleton. In particular, all of the major developmental signals (including WNT and Notch signalling), along with an increasing number of transcription factors (such as RUNX2 and osterix), have been shown to regulate the differentiation and/or function of osteoblasts. As evidence indicates that osteoblasts may also regulate the behaviour of other cell types, a clear understanding of the molecular identity and regulation of osteoblasts is important beyond the field of bone biology.

The role of osteoblasts in peri-prosthetic osteolysis.

LENUS (Irish Health Repository)

O'Neill, S C

2013-08-01

Peri-prosthetic osteolysis and subsequent aseptic loosening is the most common reason for revising total hip replacements. Wear particles originating from the prosthetic components interact with multiple cell types in the peri-prosthetic region resulting in an inflammatory process that ultimately leads to peri-prosthetic bone loss. These cells include macrophages, osteoclasts, osteoblasts and fibroblasts. The majority of research in peri-prosthetic osteolysis has concentrated on the role played by osteoclasts and macrophages. The purpose of this review is to assess the role of the osteoblast in peri-prosthetic osteolysis. In peri-prosthetic osteolysis, wear particles may affect osteoblasts and contribute to the osteolytic process by two mechanisms. First, particles and metallic ions have been shown to inhibit the osteoblast in terms of its ability to secrete mineralised bone matrix, by reducing calcium deposition, alkaline phosphatase activity and its ability to proliferate. Secondly, particles and metallic ions have been shown to stimulate osteoblasts to produce pro inflammatory mediators in vitro. In vivo, these mediators have the potential to attract pro-inflammatory cells to the peri-prosthetic area and stimulate osteoclasts to absorb bone. Further research is needed to fully define the role of the osteoblast in peri-prosthetic osteolysis and to explore its potential role as a therapeutic target in this condition.

Apoptosis may determine the release of skeletal alkaline phosphatase activity from human osteoblast-line cells.

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Farley, J R; Stilt-Coffing, B

2001-01-01

Although quantitative measurement of skeletal alkaline phosphatase (sALP) activity in serum can provide an index of the rate of bone formation, the metabolic process that determines the release of sALP - from the surface of osteoblasts, into circulation-is unknown. The current studies were intended to examine the hypothesis that the release of sALP from human osteoblasts is a consequence of apoptotic cell death. We measured the release of sALP activity from human osteosarcoma (SaOS-2) cells and normal human bone cells, under basal conditions and in response to agents that increased apoptosis (TNF-a, okadiac acid) and agents that inhibit apoptosis (IGF-I, calpain, and caspase inhibitors). Apoptosis was determined by the presence of nucleosomes (histone-associated DNA) in the cytoplasm of the cells by using a commercial kit. The results of these studies showed that TNF-a and okadiac acid caused dose- and time-dependent increases in apoptosis in the SaOS-2 cells (r = 0.78 for doses of TNF-a and r = 0.93 for doses of okadiac acid, P sALP activity (e.g., r = 0.89 for TNF-a and r = 0.75 for okadiac acid, P sALP activity (P sALP activity (P sALP release. The associations between apoptosis and sALP release were not unique to osteosarcoma (i.e., SaOS-2) cells, but also seen with osteoblast-line cells derived from normal human bone. Together, these data demonstrate that the release of sALP activity from human osteoblast-line cells in vitro is associated with, and may be a consequence of, apoptotic cell death. These findings are consistent with the general hypothesis that the appearance of sALP activity in serum may reflect the turnover of osteoblast-line cells.

Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

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Ho, Ming-Hua; Liao, Mei-Hsiu; Lin, Yi-Ling; Lai, Chien-Hao; Lin, Pei-I; Chen, Ruei-Ming

2014-01-01

Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP) messenger (m)RNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses showed that chitosan nanofibers improved osteoblast mineralization. Taken together, results of this study demonstrate that chitosan nanofibers can stimulate osteoblast proliferation and maturation via runt-related transcription factor 2-mediated regulation of osteoblast-associated osteopontin, osteocalcin, and ALP gene expression. PMID:25246786

Differentiation of Bone Marrow Mesenchymal Stem Cells in Osteoblasts and Adipocytes and its Role in Treatment of Osteoporosis.

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Wang, Cheng; Meng, Haoye; Wang, Xin; Zhao, Chenyang; Peng, Jing; Wang, Yu

2016-01-21

Osteoporosis is a systemic metabolic bone disorder characterized by a decrease in bone mass and degradation of the bone microstructure, leaving bones that are fragile and prone to fracture. Most osteoporosis treatments improve symptoms, but to date there is no quick and effective therapy. Bone marrow mesenchymal stem cells (BMMSCs) have pluripotent potential. In adults, BMMSCs differentiate mainly into osteoblasts and adipocytes in the skeleton. However, if this differentiation is unbalanced, it may lead to a decrease in bone mass. If the number of adipocyte cells increases and that of osteoblast cells decreases, osteoporosis can result. A variety of hormones and cytokines play an important role in the regulation of BMMSCs bidirectional differentiation. Therefore, a greater understanding of the regulation mechanism of BMMSC differentiation may provide new methods to prevent and treat osteoporosis. In addition, autologous, allogeneic BMMSCs or genetically modified BMMSC transplantation can effectively increase bone mass and density, increase bone mechanical strength, correct the imbalance in bone metabolism, and increase bone formation, and is expected to provide a new strategy and method for the treatment of osteoporosis.

Mechanisms of palmitate-induced cell death in human osteoblasts

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Gunaratnam, Krishanthi; Vidal, Christopher; Boadle, Ross; Thekkedam, Chris; Duque, Gustavo

2013-01-01

Summary Lipotoxicity is an overload of lipids in non-adipose tissues that affects function and induces cell death. Lipotoxicity has been demonstrated in bone cells in vitro using osteoblasts and adipocytes in coculture. In this condition, lipotoxicity was induced by high levels of saturated fatty acids (mostly palmitate) secreted by cultured adipocytes acting in a paracrine manner. In the present study, we aimed to identify the underlying mechanisms of lipotoxicity in human osteoblasts. Palmitate induced autophagy in cultured osteoblasts, which was preceded by the activation of autophagosomes that surround palmitate droplets. Palmitate also induced apoptosis though the activation of the Fas/Jun kinase (JNK) apoptotic pathway. In addition, osteoblasts could be protected from lipotoxicity by inhibiting autophagy with the phosphoinositide kinase inhibitor 3-methyladenine or by inhibiting apoptosis with the JNK inhibitor SP600125. In summary, we have identified two major molecular mechanisms of lipotoxicity in osteoblasts and in doing so we have identified a new potential therapeutic approach to prevent osteoblast dysfunction and death, which are common features of age-related bone loss and osteoporosis. PMID:24285710

Effects of extracellular magnesium extract on the proliferation and differentiation of human osteoblasts and osteoclasts in coculture.

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Wu, Lili; Feyerabend, Frank; Schilling, Arndt F; Willumeit-Römer, Regine; Luthringer, Bérengère J C

2015-11-01

Coculture of osteoblasts and osteoclasts is a subject of interest in the understanding of how magnesium (Mg)-based implants influence the bone metabolism and remodeling upon degradation. Human telomerase reverse transcriptase (hTERT) transduced mesenchymal stem cells (SCP-1) were first differentiated into osteoblasts with osteogenic supplements and then further cocultured with peripheral blood mononucleated cells (PBMC) without the addition of osteoclastogenesis promoting factors. Concomitantly, the cultures were exposed to variable Mg extract dilutions (0, 30×, 10×, 5×, 3×, 2× and 1×). Phenotype characterization documented that while 2× dilution of Mg extract was extremely toxic to osteoclast monoculture, monocytes in coculture with osteoblasts exhibited a greater tolerance to higher Mg extract concentration. The dense growth of osteoblasts in cultures with 1× dilution of Mg extract suggested that high concentration of Mg extract promoted osteoblast proliferation/differentiation behavior. The results of intracellular alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) activities as well as protein and gene expressions of receptor activator of nuclear factor kappa-B ligand (RANKL), macrophage colony-stimulating factor (M-CSF), and osteoclast-associated receptor (OSCAR) revealed significantly enhanced formation of osteoblasts whereas decreased osteoclastogenesis in the cultures with high concentrations of Mg extract (2× and 1× dilutions). In conclusion, while an increased osteoinductivity has been demonstrated, the impact of potentially decreased osteoclastogenesis around the Mg-based implants should be also taken into account. Cocultures containing both bone-forming osteoblasts and bone-resorbing osteoclasts should be preferentially performed for in vitro cytocompatibility assessment of Mg-based implants as they more closely mimic the in vivo environment. An attractive human osteoblasts and osteoclasts cocultivation regime was

Nano rough micron patterned titanium for directing osteoblast morphology and adhesion

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Sabrina Puckett

2008-06-01

Full Text Available Sabrina Puckett, Rajesh Pareta, Thomas J WebsterDivision of Engineering, Brown University, Providence, RI, USAAbstract: Previous studies have demonstrated greater functions of osteoblasts (bone-forming cells on nanophase compared with conventional metals. Nanophase metals possess a biologically inspired nanostructured surface that mimics the dimensions of constituent components in bone, including collagen and hydroxyapatite. Not only do these components possess dimensions on the nanoscale, they are aligned in a parallel manner creating a defined orientation in bone. To date, research has yet to evaluate the effect that organized nanosurface features can have on the interaction of osteoblasts with material surfaces. Therefore, to determine if surface orientation of features can mediate osteoblast adhesion and morphology, this study investigated osteoblast function on patterned titanium substrates containing alternating regions of micron rough and nano rough surfaces prepared by novel electron beam evaporation techniques. This study was also interested in determining whether or not the size of the patterned regions had an effect on osteoblast behavior and alignment. Results indicated early controlled osteoblast alignment on these patterned materials as well as greater osteoblast adhesion on the nano rough regions of these patterned substrates. Interestingly, decreasing the width of the nano rough regions (from 80 µm to 22 µm on these patterned substrates resulted in a decreased number of osteoblasts adhering to these areas. Changes in the width of the nano rough regions also resulted in changes in osteoblast morphology, thus, suggesting there is an optimal pattern dimension that osteoblasts prefer. In summary, results of this study provided evidence that aligned nanophase metal features on the surface of titanium improved early osteoblast functions (morphology and adhesion promising for their long term functions, criteria necessary to improve

Improving effects of chitosan nanofiber scaffolds on osteoblast proliferation and maturation

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Ho MH

2014-09-01

Full Text Available Ming-Hua Ho,1,2 Mei-Hsiu Liao,3 Yi-Ling Lin,2 Chien-Hao Lai,3 Pei-I Lin,3 Ruei-Ming Chen2–4 1Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 2Cell Physiology and Molecular Image Research Center and Department of Anesthesiology, Wan Fang Hospital, 3Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan; 4Anesthetics and Toxicology Research Center, Taipei Medical University Hospital, Taipei, Taiwan Abstract: Osteoblast maturation plays a key role in regulating osteogenesis. Electrospun nanofibrous products were reported to possess a high surface area and porosity. In this study, we developed chitosan nanofibers and examined the effects of nanofibrous scaffolds on osteoblast maturation and the possible mechanisms. Macro- and micro observations of the chitosan nanofibers revealed that these nanoproducts had a flat surface and well-distributed fibers with nanoscale diameters. Mouse osteoblasts were able to attach onto the chitosan nanofiber scaffolds, and the scaffolds degraded in a time-dependent manner. Analysis by scanning electron microscopy further showed mouse osteoblasts adhered onto the scaffolds along the nanofibers, and cell–cell communication was also detected. Mouse osteoblasts grew much better on chitosan nanofiber scaffolds than on chitosan films. In addition, human osteoblasts were able to adhere and grow on the chitosan nanofiber scaffolds. Interestingly, culturing human osteoblasts on chitosan nanofiber scaffolds time-dependently increased DNA replication and cell proliferation. In parallel, administration of human osteoblasts onto chitosan nanofibers significantly induced osteopontin, osteocalcin, and alkaline phosphatase (ALP messenger (mRNA expression. As to the mechanism, chitosan nanofibers triggered runt-related transcription factor 2 mRNA and protein syntheses. Consequently, results of ALP-, alizarin red-, and von Kossa-staining analyses

Osteoblast recruitment routes in human cancellous bone remodeling

DEFF Research Database (Denmark)

Kristensen, Helene Bjørg; Andersen, Thomas Levin; Marcussen, Niels

2014-01-01

It is commonly proposed that bone forming osteoblasts recruited during bone remodeling originate from bone marrow perivascular cells, bone remodeling compartment canopy cells, or bone lining cells. However, an assessment of osteoblast recruitment during adult human cancellous bone remodeling...... is lacking. We addressed this question by quantifying cell densities, cell proliferation, osteoblast differentiation markers, and capillaries in human iliac crest biopsy specimens. We found that recruitment occurs on both reversal and bone-forming surfaces, as shown by the cell density and osterix levels...

Platelet-rich plasma stimulates osteoblastic differentiation in the presence of BMPs

International Nuclear Information System (INIS)

Tomoyasu, Akihiro; Higashio, Kanji; Kanomata, Kazuhiro; Goto, Masaaki; Kodaira, Kunihiko; Serizawa, Hiroko; Suda, Tatsuo; Nakamura, Atsushi; Nojima, Junya; Fukuda, Toru; Katagiri, Takenobu

2007-01-01

Platelet-rich plasma (PRP) is clinically used as an autologous blood product to stimulate bone formation in vivo. In the present study, we examined the effects of PRP on proliferation and osteoblast differentiation in vitro in the presence of bone morphogenetic proteins (BMPs). PRP and its soluble fraction stimulated osteoblastic differentiation of myoblasts and osteoblastic cells in the presence of BMP-2, BMP-4, BMP-6 or BMP-7. The soluble PRP fraction stimulated osteoblastic differentiation in 3D cultures using scaffolds made of collagen or hydroxyapatite. Moreover, heparin-binding fractions obtained from serum also stimulated osteoblastic differentiation in the presence of BMP-4. These results suggested that platelets contain not only growth factors for proliferation but also novel potentiator(s) for BMP-dependent osteoblastic differentiation

Biglycan deficiency increases osteoclast differentiation and activity due to defective osteoblasts

DEFF Research Database (Denmark)

Bi, Yanming; Nielsen, Karina L; Kilts, Tina M

2006-01-01

to be independent of the differential production of soluble RANKL and OPG and, instead, due to a decrease in osteoblast maturation accompanied by increase in osteoblastic proliferation. In addition to the imbalance between differentiation and proliferation, there was a differential decrease in secretory leukocyte......Bone mass is maintained by a fine balance between bone formation by osteoblasts and bone resorption by osteoclasts. Although osteoblasts and osteoclasts have different developmental origins, it is generally believed that the differentiation, function, and survival of osteoclasts are regulated...... by osteogenic cells. We have previously shown that the extracellular matrix protein, biglycan (Bgn), plays an important role in the differentiation of osteoblast precursors. In this paper, we showed that Bgn is involved in regulating osteoclast differentiation through its effect on osteoblasts...

Toxicity of iron oxide nanoparticles against osteoblasts

International Nuclear Information System (INIS)

Shi Sifeng; Jia Jingfu; Guo Xiaokui; Zhao Yaping; Liu Boyu; Chen Desheng; Guo Yongyuan; Zhang Xianlong

2012-01-01

Magnetic nanoparticles have been widely used for tissue repair, magnetic resonance imaging, immunoassays and drug delivery. They are very promising in orthopaedic applications and several magnetic nanoparticles have been exploited for the treatment of orthopaedic disease. Here, we conducted an in vitro study to examine the interaction of magnetic iron oxide nanoparticles with human osteoblasts to evaluate the dose-related toxicity of the nanoparticles on osteoblasts. A transmission electron microscope was used to visualise the internalised magnetic nanoparticles in osteoblasts. The CCK-8 results revealed increased cell viability (107.5 % vitality compared with the control group) when co-cultured at a low concentration (20 μg/mL) and decreased cell viability (59.5 % vitality in a concentration of 300 μg/mL and 25.9 % in 500 μg/mL) when co-cultured in high concentrations. The flow cytometric detection revealed similar results with 5.48 % of apoptosis in a concentration of 20 μg/mL, 23.40 % of apoptosis in a concentration of 300 μg/mL and 28.49 % in a concentration of 500 μg/mL. The disrupted cytoskeleton of osteoblasts was also revealed using a laser scanning confocal microscope. We concluded that use of a low concentration of magnetic iron oxide nanoparticles is important to avoid damage to osteoblasts.

Toxicity of iron oxide nanoparticles against osteoblasts

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Shi Sifeng [Shanghai Jiao Tong University, Department of Orthopaedic Surgery, Shanghai Sixth People' s Hospital (China); Jia Jingfu [Shanghai Jiao Tong University, School of Chemistry and Chemical Technology (China); Guo Xiaokui [Shanghai Jiao Tong University School of Medicine, Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences (China); Zhao Yaping [Shanghai Jiao Tong University, School of Chemistry and Chemical Technology (China); Liu Boyu [Shanghai Jiao Tong University School of Medicine, Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences (China); Chen Desheng; Guo Yongyuan; Zhang Xianlong, E-mail: zhangxianlong20101@163.com [Shanghai Jiao Tong University, Department of Orthopaedic Surgery, Shanghai Sixth People' s Hospital (China)

2012-09-15

Magnetic nanoparticles have been widely used for tissue repair, magnetic resonance imaging, immunoassays and drug delivery. They are very promising in orthopaedic applications and several magnetic nanoparticles have been exploited for the treatment of orthopaedic disease. Here, we conducted an in vitro study to examine the interaction of magnetic iron oxide nanoparticles with human osteoblasts to evaluate the dose-related toxicity of the nanoparticles on osteoblasts. A transmission electron microscope was used to visualise the internalised magnetic nanoparticles in osteoblasts. The CCK-8 results revealed increased cell viability (107.5 % vitality compared with the control group) when co-cultured at a low concentration (20 {mu}g/mL) and decreased cell viability (59.5 % vitality in a concentration of 300 {mu}g/mL and 25.9 % in 500 {mu}g/mL) when co-cultured in high concentrations. The flow cytometric detection revealed similar results with 5.48 % of apoptosis in a concentration of 20 {mu}g/mL, 23.40 % of apoptosis in a concentration of 300 {mu}g/mL and 28.49 % in a concentration of 500 {mu}g/mL. The disrupted cytoskeleton of osteoblasts was also revealed using a laser scanning confocal microscope. We concluded that use of a low concentration of magnetic iron oxide nanoparticles is important to avoid damage to osteoblasts.

Cancer Metastases to Bone: Concepts, Mechanisms, and Interactions with Bone Osteoblasts

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Alison B. Shupp

2018-06-01

Full Text Available The skeleton is a unique structure capable of providing support for the body. Bone resorption and deposition are controlled in a tightly regulated balance between osteoblasts and osteoclasts with no net bone gain or loss. However, under conditions of disease, the balance between bone resorption and deposition is upset. Osteoblasts play an important role in bone homeostasis by depositing new bone osteoid into resorption pits. It is becoming increasingly evident that osteoblasts additionally play key roles in cancer cell dissemination to bone and subsequent metastasis. Our laboratory has evidence that when osteoblasts come into contact with disseminated breast cancer cells, the osteoblasts produce factors that initially reduce breast cancer cell proliferation, yet promote cancer cell survival in bone. Other laboratories have demonstrated that osteoblasts both directly and indirectly contribute to dormant cancer cell reactivation in bone. Moreover, we have demonstrated that osteoblasts undergo an inflammatory stress response in late stages of breast cancer, and produce inflammatory cytokines that are maintenance and survival factors for breast cancer cells and osteoclasts. Advances in understanding interactions between osteoblasts, osteoclasts, and bone metastatic cancer cells will aid in controlling and ultimately preventing cancer cell metastasis to bone.

Different Expression and Localization of Phosphoinositide Specific Phospholipases C in Human Osteoblasts, Osteosarcoma Cell Lines, Ewing Sarcoma and Synovial Sarcoma

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V.Vasco

2017-06-01

Full Text Available Background: Bone hardness and strength depends on mineralization, which involves a complex process in which calcium phosphate, produced by bone-forming cells, was shed around the fibrous matrix. This process is strictly regulated, and a number of signal transduction systems were interested in calcium metabolism, such as the phosphoinositide (PI pathway and related phospholipase C (PLC enzymes. Objectives: Our aim was to search for common patterns of expression in osteoblasts, as well as in ES and SS. Methods: We analysed the PLC enzymes in human osteoblasts and osteosarcoma cell lines MG-63 and SaOS-2. We compared the obtained results to the expression of PLCs in samples of patients affected with Ewing sarcoma (ES and synovial sarcoma (SS. Results: In osteoblasts, MG-63 cells and SaOS-2 significant differences were identified in the expression of PLC δ4 and PLC η subfamily isoforms. Differences were also identified regarding the expression of PLCs in ES and SS. Most ES and SS did not express PLCB1, which was expressed in most osteoblasts, MG-63 and SaOS-2 cells. Conversely, PLCB2, unexpressed in the cell lines, was expressed in some ES and SS. However, PLCH1 was expressed in SaOS-2 and inconstantly expressed in osteoblasts, while it was expressed in ES and unexpressed in SS. The most relevant difference observed in ES compared to SS regarded PLC ε and PLC η isoforms. Conclusion: MG-63 and SaOS-2 osteosarcoma cell lines might represent an inappropriate experimental model for studies about the analysis of signal transduction in osteoblasts

Osteoblast Production by Reserved Progenitor Cells in Zebrafish Bone Regeneration and Maintenance.

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Ando, Kazunori; Shibata, Eri; Hans, Stefan; Brand, Michael; Kawakami, Atsushi

2017-12-04

Mammals cannot re-form heavily damaged bones as in large fracture gaps, whereas zebrafish efficiently regenerate bones even after amputation of appendages. However, the source of osteoblasts that mediate appendage regeneration is controversial. Several studies in zebrafish have shown that osteoblasts are generated by dedifferentiation of existing osteoblasts at injured sites, but other observations suggest that de novo production of osteoblasts also occurs. In this study, we found from cell-lineage tracing and ablation experiments that a group of cells reserved in niches serves as osteoblast progenitor cells (OPCs) and has a significant role in fin ray regeneration. Besides regeneration, OPCs also supply osteoblasts for normal bone maintenance. We further showed that OPCs are derived from embryonic somites, as is the case with embryonic osteoblasts, and are replenished from mesenchymal precursors in adult zebrafish. Our findings reveal that reserved progenitors are a significant and complementary source of osteoblasts for zebrafish bone regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Estradiol influences the mechanical properties of human fetal osteoblasts through cytoskeletal changes

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Muthukumaran, Padmalosini [Department of Bioengineering, National University of Singapore (Singapore); Lim, Chwee Teck [Department of Bioengineering, National University of Singapore (Singapore); Department of Mechanical Engineering, National University of Singapore (Singapore); Mechanobiology Institute, National University of Singapore (Singapore); Singapore-MIT Alliance for Research and Technology (SMART), National University of Singapore (Singapore); Lee, Taeyong, E-mail: bielt@nus.edu.sg [Department of Bioengineering, National University of Singapore (Singapore)

2012-07-06

Highlights: Black-Right-Pointing-Pointer Estradiol induced stiffness changes of osteoblasts were quantified using AFM. Black-Right-Pointing-Pointer Estradiol causes significant decrease in the stiffness of osteoblasts. Black-Right-Pointing-Pointer Decreased stiffness was caused by decreased density of f-actin network. Black-Right-Pointing-Pointer Stiffness changes were not associated with mineralized matrix of osteoblasts. Black-Right-Pointing-Pointer Estradiol increases inherent alkaline phosphatase activity of osteoblasts. -- Abstract: Estrogen is known to have a direct effect on bone forming osteoblasts and bone resorbing osteoclasts. The cellular and molecular effects of estrogen on osteoblasts and osteoblasts-like cells have been extensively studied. However, the effect of estrogen on the mechanical property of osteoblasts has not been studied yet. It is important since mechanical property of the mechanosensory osteoblasts could be pivotal to its functionality in bone remodeling. This is the first study aimed to assess the direct effect of estradiol on the apparent elastic modulus (E{sup Asterisk-Operator }) and corresponding cytoskeletal changes of human fetal osteoblasts (hFOB 1.19). The cells were cultured in either medium alone or medium supplemented with {beta}-estradiol and then subjected to Atomic Force Microscopy indentation (AFM) to determine E{sup Asterisk-Operator }. The underlying changes in cytoskeleton were studied by staining the cells with TRITC-Phalloidin. Following estradiol treatment, the cells were also tested for proliferation, alkaline phosphatase activity and mineralization. With estradiol treatment, E{sup Asterisk-Operator} of osteoblasts significantly decreased by 43-46%. The confocal images showed that the changes in f-actin network observed in estradiol treated cells can give rise to the changes in the stiffness of the cells. Estradiol also increases the inherent alkaline phosphatase activity of the cells. Estradiol induced stiffness

Estradiol influences the mechanical properties of human fetal osteoblasts through cytoskeletal changes

International Nuclear Information System (INIS)

Muthukumaran, Padmalosini; Lim, Chwee Teck; Lee, Taeyong

2012-01-01

Highlights: ► Estradiol induced stiffness changes of osteoblasts were quantified using AFM. ► Estradiol causes significant decrease in the stiffness of osteoblasts. ► Decreased stiffness was caused by decreased density of f-actin network. ► Stiffness changes were not associated with mineralized matrix of osteoblasts. ► Estradiol increases inherent alkaline phosphatase activity of osteoblasts. -- Abstract: Estrogen is known to have a direct effect on bone forming osteoblasts and bone resorbing osteoclasts. The cellular and molecular effects of estrogen on osteoblasts and osteoblasts-like cells have been extensively studied. However, the effect of estrogen on the mechanical property of osteoblasts has not been studied yet. It is important since mechanical property of the mechanosensory osteoblasts could be pivotal to its functionality in bone remodeling. This is the first study aimed to assess the direct effect of estradiol on the apparent elastic modulus (E ∗ ) and corresponding cytoskeletal changes of human fetal osteoblasts (hFOB 1.19). The cells were cultured in either medium alone or medium supplemented with β-estradiol and then subjected to Atomic Force Microscopy indentation (AFM) to determine E ∗ . The underlying changes in cytoskeleton were studied by staining the cells with TRITC-Phalloidin. Following estradiol treatment, the cells were also tested for proliferation, alkaline phosphatase activity and mineralization. With estradiol treatment, E ∗ of osteoblasts significantly decreased by 43–46%. The confocal images showed that the changes in f-actin network observed in estradiol treated cells can give rise to the changes in the stiffness of the cells. Estradiol also increases the inherent alkaline phosphatase activity of the cells. Estradiol induced stiffness changes of osteoblasts were not associated with changes in the synthesized mineralized matrix of the cells. Thus, a decrease in osteoblast stiffness with estrogen treatment was

Osteoblast-like MC3T3-E1 Cells Prefer Glycolysis for ATP Production but Adipocyte-like 3T3-L1 Cells Prefer Oxidative Phosphorylation.

Science.gov (United States)

Guntur, Anyonya R; Gerencser, Akos A; Le, Phuong T; DeMambro, Victoria E; Bornstein, Sheila A; Mookerjee, Shona A; Maridas, David E; Clemmons, David E; Brand, Martin D; Rosen, Clifford J

2018-06-01

Mesenchymal stromal cells (MSCs) are early progenitors that can differentiate into osteoblasts, chondrocytes, and adipocytes. We hypothesized that osteoblasts and adipocytes utilize distinct bioenergetic pathways during MSC differentiation. To test this hypothesis, we compared the bioenergetic profiles of preosteoblast MC3T3-E1 cells and calvarial osteoblasts with preadipocyte 3T3L1 cells, before and after differentiation. Differentiated MC3T3-E1 osteoblasts met adenosine triphosphate (ATP) demand mainly by glycolysis with minimal reserve glycolytic capacity, whereas nondifferentiated cells generated ATP through oxidative phosphorylation. A marked Crabtree effect (acute suppression of respiration by addition of glucose, observed in both MC3T3-E1 and calvarial osteoblasts) and smaller mitochondrial membrane potential in the differentiated osteoblasts, particularly those incubated at high glucose concentrations, indicated a suppression of oxidative phosphorylation compared with nondifferentiated osteoblasts. In contrast, both nondifferentiated and differentiated 3T3-L1 adipocytes met ATP demand primarily by oxidative phosphorylation despite a large unused reserve glycolytic capacity. In sum, we show that nondifferentiated precursor cells prefer to use oxidative phosphorylation to generate ATP; when they differentiate to osteoblasts, they gain a strong preference for glycolytic ATP generation, but when they differentiate to adipocytes, they retain the strong preference for oxidative phosphorylation. Unique metabolic programming in mesenchymal progenitor cells may influence cell fate and ultimately determine the degree of bone formation and/or the development of marrow adiposity. © 2018 American Society for Bone and Mineral Research. © 2018 American Society for Bone and Mineral Research.

Evolution of the osteoblast: skeletogenesis in gar and zebrafish

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Eames B Frank

2012-03-01

Full Text Available Abstract Background Although the vertebrate skeleton arose in the sea 500 million years ago, our understanding of the molecular fingerprints of chondrocytes and osteoblasts may be biased because it is informed mainly by research on land animals. In fact, the molecular fingerprint of teleost osteoblasts differs in key ways from that of tetrapods, but we do not know the origin of these novel gene functions. They either arose as neofunctionalization events after the teleost genome duplication (TGD, or they represent preserved ancestral functions that pre-date the TGD. Here, we provide evolutionary perspective to the molecular fingerprints of skeletal cells and assess the role of genome duplication in generating novel gene functions. We compared the molecular fingerprints of skeletogenic cells in two ray-finned fish: zebrafish (Danio rerio--a teleost--and the spotted gar (Lepisosteus oculatus--a "living fossil" representative of a lineage that diverged from the teleost lineage prior to the TGD (i.e., the teleost sister group. We analyzed developing embryos for expression of the structural collagen genes col1a2, col2a1, col10a1, and col11a2 in well-formed cartilage and bone, and studied expression of skeletal regulators, including the transcription factor genes sox9 and runx2, during mesenchymal condensation. Results Results provided no evidence for the evolution of novel functions among gene duplicates in zebrafish compared to the gar outgroup, but our findings shed light on the evolution of the osteoblast. Zebrafish and gar chondrocytes both expressed col10a1 as they matured, but both species' osteoblasts also expressed col10a1, which tetrapod osteoblasts do not express. This novel finding, along with sox9 and col2a1 expression in developing osteoblasts of both zebrafish and gar, demonstrates that osteoblasts of both a teleost and a basally diverging ray-fin fish express components of the supposed chondrocyte molecular fingerprint. Conclusions Our

Matrix metalloproteinases (MMPs) safeguard osteoblasts from apoptosis during transdifferentiation into osteocytes

DEFF Research Database (Denmark)

Karsdal, M A; Levin Andersen, Thomas; Bonewald, L

2004-01-01

of osteoblasts forced to transdifferentiate into osteocytes in 3D type I collagen gels were inhibited by more than 50% when exposed to 10 microM GM6001 and to Tissue Inhibitor of Metalloproteinase-2 (TIMP-2), a natural MT1-MMP inhibitor. This shows the importance of MMPs in safeguarding osteoblasts from......Osteoblasts undergo apoptosis or differentiate into either osteocytes or bone-lining cells after termination of bone matrix synthesis. In this study, we investigated the role of matrix metalloproteinases (MMPs) in differentiation of osteoblasts, bone formation, transdifferentiation into osteocytes......, and osteocyte apoptosis. This was accomplished by using calvarial sections from the MT1-MMP-deficient mouse and by culture of the mouse osteoblast cell line MC3T3-E1 and primary mouse calvarial osteoblasts. We found that a synthetic matrix metalloprotease inhibitor, GM6001, strongly inhibited bone formation...

Identification and proteomic analysis of osteoblast-derived exosomes

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Ge, Min; Ke, Ronghu; Cai, Tianyi; Yang, Junyi; Mu, Xiongzheng, E-mail: cranio@vip.163.com

2015-11-06

Exosomes are nanometer-sized vesicles with the function of intercellular communication, and they are released by various cell types. To reveal the knowledge about the exosomes from osteoblast, and explore the potential functions of osteogenesis, we isolated microvesicles from supernatants of mouse Mc3t3 by ultracentrifugation, characterized exosomes by electron microscopy and immunoblotting and presented the protein profile by proteomic analysis. The result demonstrated that microvesicles were between 30 and 100 nm in diameter, round shape with cup-like concavity and expressed exosomal marker tumor susceptibility gene (TSG) 101 and flotillin (Flot) 1. We identified a total number of 1069 proteins among which 786 proteins overlap with ExoCarta database. Gene Oncology analysis indicated that exosomes mostly derived from plasma membrane and mainly involved in protein localization and intracellular signaling. The Ingenuity Pathway Analysis showed pathways are mostly involved in exosome biogenesis, formation, uptake and osteogenesis. Among the pathways, eukaryotic initiation factor 2 pathways played an important role in osteogenesis. Our study identified osteoblast-derived exosomes, unveiled the content of them, presented potential osteogenesis-related proteins and pathways and provided a rich proteomics data resource that will be valuable for further studies of the functions of individual proteins in bone diseases. - Highlights: • We for the first time identified exosomes from mouse osteoblast. • Osteoblasts-derived exosomes contain osteoblast peculiar proteins. • Proteins from osteoblasts-derived exosomes are intently involved in EIF2 pathway. • EIF2α from the EIF2 pathway plays an important role in osteogenesis.

Rotary culture enhances pre-osteoblast aggregation and mineralization.

Science.gov (United States)

Facer, S R; Zaharias, R S; Andracki, M E; Lafoon, J; Hunter, S K; Schneider, G B

2005-06-01

Three-dimensional environments have been shown to enhance cell aggregation and osteoblast differentiation. Thus, we hypothesized that three-dimensional (3D) growth environments would enhance the mineralization rate of human embryonic palatal mesenchymal (HEPM) pre-osteoblasts. The objective of this study was to investigate the potential use of rotary cell culture systems (RCCS) as a means to enhance the osteogenic potential of pre-osteoblast cells. HEPM cells were cultured in a RCCS to create 3D enviroments. Tissue culture plastic (2D) cultures served as our control. 3D environments promoted three-dimensional aggregate formations. Increased calcium and phosphorus deposition was significantly enhanced three- to 18-fold (P < 0.001) in 3D cultures as compared with 2D environments. 3D cultures mineralized in 1 wk as compared with the 2D cultures, which took 4 wks, a decrease in time of nearly 75%. In conclusion, our studies demonstrated that 3D environments enhanced osteoblast cell aggregation and mineralization.

Osteocytes subjected to pulsating fluid flow regulate osteoblast proliferation and differentiation

International Nuclear Information System (INIS)

Vezeridis, Peter S.; Semeins, Cornelis M.; Chen Qian; Klein-Nulend, Jenneke

2006-01-01

Osteocytes are thought to orchestrate bone remodeling, but it is unclear exactly how osteocytes influence neighboring bone cells. Here, we tested whether osteocytes, osteoblasts, and periosteal fibroblasts subjected to pulsating fluid flow (PFF) produce soluble factors that modulate the proliferation and differentiation of cultured osteoblasts and periosteal fibroblasts. We found that osteocyte PFF conditioned medium (CM) inhibited bone cell proliferation, and osteocytes produced the strongest inhibition of proliferation compared to osteoblasts and periosteal fibroblasts. The nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) attenuated the inhibitory effects of osteocyte PFF CM, suggesting that a change in NO release is at least partially responsible for the inhibitory effects of osteocyte PFF CM. Furthermore, osteocyte PFF CM stimulated osteoblast differentiation measured as increased alkaline phosphatase activity, and L-NAME decreased the stimulatory effects of osteocyte PFF CM on osteoblast differentiation. We conclude that osteocytes subjected to PFF inhibit proliferation but stimulate differentiation of osteoblasts in vitro via soluble factors and that the release of these soluble factors was at least partially dependent on the activation of a NO pathway in osteocytes in response to PFF. Thus, the osteocyte appears to be more responsive to PFF than the osteoblast or periosteal fibroblast with respect to the production of soluble signaling molecules affecting osteoblast proliferation and differentiation

Edaravone protects osteoblastic cells from dexamethasone through inhibiting oxidative stress and mPTP opening.

Science.gov (United States)

Sun, Wen-xiao; Zheng, Hai-ya; Lan, Jun

2015-11-01

Existing evidences have emphasized an important role of oxidative stress in dexamethasone (Dex)-induced osteoblastic cell damages. Here, we investigated the possible anti-Dex activity of edaravone in osteoblastic cells, and studied the underlying mechanisms. We showed that edaravone dose-dependently attenuated Dex-induced death and apoptosis of established human or murine osteoblastic cells. Further, Dex-mediated damages to primary murine osteoblasts were also alleviated by edaravone. In osteoblastic cells/osteoblasts, Dex induced significant oxidative stresses, tested by increased levels of reactive oxygen species and lipid peroxidation, which were remarkably inhibited by edaravone. Meanwhile, edaravone repressed Dex-induced mitochondrial permeability transition pore (mPTP) opening, or mitochondrial membrane potential reduction, in osteoblastic cells/osteoblasts. Significantly, edaravone-induced osteoblast-protective activity against Dex was alleviated with mPTP inhibition through cyclosporin A or cyclophilin-D siRNA. Together, we demonstrate that edaravone protects osteoblasts from Dex-induced damages probably through inhibiting oxidative stresses and following mPTP opening.

Direct conversion of human fibroblasts into functional osteoblasts by defined factors.

Science.gov (United States)

Yamamoto, Kenta; Kishida, Tsunao; Sato, Yoshiki; Nishioka, Keisuke; Ejima, Akika; Fujiwara, Hiroyoshi; Kubo, Toshikazu; Yamamoto, Toshiro; Kanamura, Narisato; Mazda, Osam

2015-05-12

Osteoblasts produce calcified bone matrix and contribute to bone formation and remodeling. In this study, we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some defined factors and culturing in osteogenic medium. Osteoblast-specific transcription factors, Runt-related transcription factor 2 (Runx2), and Osterix, in combination with Octamer-binding transcription factor 3/4 (Oct4) and L-Myc (RXOL) transduction, converted ∼ 80% of the fibroblasts into osteocalcin-producing cells. The directly converted osteoblasts (dOBs) induced by RXOL displayed a similar gene expression profile as normal human osteoblasts and contributed to bone repair after transplantation into immunodeficient mice at artificial bone defect lesions. The dOBs expressed endogenous Runx2 and Osterix, and did not require continuous expression of the exogenous genes to maintain their phenotype. Another combination, Oct4 plus L-Myc (OL), also induced fibroblasts to produce bone matrix, but the OL-transduced cells did not express Osterix and exhibited a more distant gene expression profile to osteoblasts compared with RXOL-transduced cells. These findings strongly suggest successful direct reprogramming of fibroblasts into functional osteoblasts by RXOL, a technology that may provide bone regeneration therapy against bone disorders.

Arsenic induces cell apoptosis in cultured osteoblasts through endoplasmic reticulum stress

International Nuclear Information System (INIS)

Tang, C.-H.; Chiu, Y.-C.; Huang, C.-F.; Chen, Y.-W.; Chen, P.-C.

2009-01-01

Osteoporosis is characterized by low bone mass resulting from an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts. Therefore, decreased bone formation by osteoblasts may lead to the development of osteoporosis, and rate of apoptosis is responsible for the regulation of bone formation. Arsenic (As) exists ubiquitously in our environment and increases the risk of neurotoxicity, liver injury, peripheral vascular disease and cancer. However, the effect of As on apoptosis of osteoblasts is mostly unknown. Here, we found that As induced cell apoptosis in osteoblastic cell lines (including hFOB, MC3T3-E1 and MG-63) and mouse bone marrow stromal cells (M2-10B4). As also induced upregulation of Bax and Bak, downregulation of Bcl-2 and dysfunction of mitochondria in osteoblasts. As also triggered endoplasmic reticulum (ER) stress, as indicated by changes in cytosolic-calcium levels. We found that As increased the expression and activities of glucose-regulated protein 78 (GRP78) and calpain. Transfection of cells with GRP78 or calpain siRNA reduced As-mediated cell apoptosis in osteoblasts. Therefore, our results suggest that As increased cell apoptosis in cultured osteoblasts and increased the risk of osteoporosis.

Mechanisms regulating osteoblast response to surface microtopography and vitamin D

Science.gov (United States)

Bell, Bryan Frederick, Jr.

A comprehensive understanding of the interactions between orthopaedic and dental implant surfaces with the surrounding host tissue is essential in the design of advanced biomaterials that better promote bone growth and osseointegration of implants. Dental implants with roughened surfaces and high surface energy are well known to promote osteoblast differentiation in vitro and promote increased bone-to-implant contact in vivo. In addition, increased surface roughness increases osteoblasts response to the vitamin D metabolite 1alpha,25(OH)2D3. However, the exact mechanisms mediating cell response to surface properties and 1alpha,25(OH)2D3 are still being elucidated. The central aim of the thesis is to investigate whether integrin signaling in response to rough surface microtopography enhances osteoblast differentiation and responsiveness to 1alpha,25(OH)2D3. The hypothesis is that the integrin alpha5beta1 plays a role in osteoblast response to surface microtopography and that 1alpha,25(OH) 2D3 acts through VDR-independent pathways involving caveolae to synergistically enhance osteoblast response to surface roughness and 1alpha,25(OH) 2D3. To test this hypothesis the objectives of the studies performed in this thesis were: (1) to determine if alpha5beta 1 signaling is required for osteoblast response to surface microstructure; (2) to determine if increased responsiveness to 1alpha,25(OH)2D 3 requires the vitamin D receptor, (3) to determine if rough titanium surfaces functionalized with the peptides targeting integrins (RGD) and transmembrane proteoglycans (KRSR) will enhance both osteoblast proliferation and differentiation, and (4) to determine whether caveolae, which are associated with integrin and 1alpha,25(OH)2D3 signaling, are required for enhance osteogenic response to surface microstructure and 1alpha,25(OH)2D 3. The results demonstrate that integrins, VDR, and caveolae play important roles in mediating osteoblast response to surface properties and 1alpha,25

Establishment of a new model for culturing rabbit osteoblasts in vitro

International Nuclear Information System (INIS)

Cao Xianying; Yin Meizhen; Zhang Lina; Li Shipu; Cao Yang

2006-01-01

To establish an experimental model for culturing rabbit osteoblasts in vitro, the osteoblasts were isolated from the calvarial bone of a 15-day old rabbit using a method of culturing the bone pieces in a medium after they had been digested by an enzyme for 15 min. The acquired cells were assayed by cell morphology, alkaline phosphatase activity and production of a mineralized matrix. The results showed that the cells had the morphologic characteristics and some biological behaviours of osteoblasts. Based on the primary isolation of osteoblasts from bone and combining digestion with explants, a novel model for culturing rabbit osteoblasts in vitro was established, which is easy, efficient and effective. This model can be used in many studies of osteogenesis mechanisms and bone replacement materials. (communication)

Immortalization and characterization of mouse floxed Bmp2/4 osteoblasts

International Nuclear Information System (INIS)

Wu, Li-An; Yuan, Guohua; Yang, Guobin; Ortiz-Gonzalez, Iris; Yang, Wuchen; Cui, Yong; MacDougall, Mary; Donly, Kevin J.; Harris, Stephen; Chen, Shuo

2009-01-01

Generation of a floxed Bmp2/4 osteoblast cell line is a valuable tool for studying the modulatory effects of Bmp2 and Bmp4 on osteoblast differentiation as well as relevant molecular events. In this study, primary floxed Bmp2/4 mouse osteoblasts were cultured and transfected with simian virus 40 large T-antigen. Transfection was verified by polymerase chain reaction (PCR) and immunohistochemistry. To examine the characteristics of the transfected cells, morphology, proliferation and mineralization were analyzed, expression of cell-specific genes including Runx2, ATF4, Dlx3, Osx, dentin matrix protein 1, bone sialoprotein, osteopontin, osteocalcin, osteonectin and collagen type I was detected. These results show that transfected floxed Bmp2/4 osteoblasts bypassed senescence with a higher proliferation rate, but retain the genotypic and phenotypic characteristics similar to the primary cells. Thus, we for the first time demonstrate the establishment of an immortalized mouse floxed Bmp2/4 osteoblast cell line.

Immortalization and characterization of mouse floxed Bmp2/4 osteoblasts

Energy Technology Data Exchange (ETDEWEB)

Wu, Li-An [Department of Pediatric Dentistry, The University of Texas Health Science Center at San Antonio, TX (United States); Department of Pediatric Dentistry, School of Stomatology, The Fourth Military Medical University, Xi-an (China); Yuan, Guohua; Yang, Guobin [Department of Pediatric Dentistry, The University of Texas Health Science Center at San Antonio, TX (United States); Key Laboratory of Oral Biomedical Engineering Ministry of Education, Wuhan (China); Ortiz-Gonzalez, Iris [Department of Pediatric Dentistry, The University of Texas Health Science Center at San Antonio, TX (United States); Yang, Wuchen; Cui, Yong [Department of Periodontics, Dental School, The University of Texas Health Science Center at San Antonio, TX (United States); MacDougall, Mary [Department of Oral/Maxillofacial Surgery, University of Alabama, Birmingham, AL (United States); Donly, Kevin J. [Department of Pediatric Dentistry, The University of Texas Health Science Center at San Antonio, TX (United States); Harris, Stephen [Department of Periodontics, Dental School, The University of Texas Health Science Center at San Antonio, TX (United States); Chen, Shuo, E-mail: chens0@uthscsa.edu [Department of Pediatric Dentistry, The University of Texas Health Science Center at San Antonio, TX (United States)

2009-08-14

Generation of a floxed Bmp2/4 osteoblast cell line is a valuable tool for studying the modulatory effects of Bmp2 and Bmp4 on osteoblast differentiation as well as relevant molecular events. In this study, primary floxed Bmp2/4 mouse osteoblasts were cultured and transfected with simian virus 40 large T-antigen. Transfection was verified by polymerase chain reaction (PCR) and immunohistochemistry. To examine the characteristics of the transfected cells, morphology, proliferation and mineralization were analyzed, expression of cell-specific genes including Runx2, ATF4, Dlx3, Osx, dentin matrix protein 1, bone sialoprotein, osteopontin, osteocalcin, osteonectin and collagen type I was detected. These results show that transfected floxed Bmp2/4 osteoblasts bypassed senescence with a higher proliferation rate, but retain the genotypic and phenotypic characteristics similar to the primary cells. Thus, we for the first time demonstrate the establishment of an immortalized mouse floxed Bmp2/4 osteoblast cell line.

Stimulatory effect of undecylenic acid on mouse osteoblast differentiation.

Science.gov (United States)

Kim, Myung Hee; Shim, Ki Shuk; Lee, Su-Ui; Kim, Young Sup; Min, Yong Ki; Kim, Seong Hwan

2010-04-01

Natural compounds with bone-forming (or anabolic) activity have been recently focused on in bone research. The present study investigated the effect of undecylenic acid (UA) on osteoblast differentiation in mouse osteoblastic MC3T3-E1 subclone 4 cells and primary mouse calvarial cells. Low concentrations of UA (up to 5 microM) exhibited no cytotoxicity and significantly increased the expression and activity of alkaline phosphatase (early differentiation marker of osteoblast) and calcium deposition with the induction of expression of the osteocalcin gene in both cells. Interestingly, at low concentration of UA, the induction of NF-kappaB p65 translocation into nucleus and the up-regulation of AP-1 and NFATc1 transcript levels were also observed, suggesting that the stimulatory effect of UA on osteoblast differentiation could be mediated through the activation of transcription factors. Additionally, although the patterns of UA-induced activation of MAP kinases (JNK and p38) were not completely consistent with the increase of both ALP activity and calcium deposition by UA, MAP kinases might be partially involved in the biological function of UA during the early and late stages of osteoblast differentiation. Copyright (c) 2009 John Wiley & Sons, Ltd.

Adhesion of osteoblasts to a nanorough titanium implant surface

Directory of Open Access Journals (Sweden)

Gongadze E

2011-08-01

Full Text Available Ekaterina Gongadze1, Doron Kabaso2, Sebastian Bauer3, Tomaž Slivnik2, Patrik Schmuki3, Ursula van Rienen1, Aleš Iglič21Institute of General Electrical Engineering, University of Rostock, Rostock, Germany; 2Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia; 3Department of Materials Science, Friedrich-Alexander University of Erlangen-Nurenberg, Erlangen, GermanyAbstract: This work considers the adhesion of cells to a nanorough titanium implant surface with sharp edges. The basic assumption was that the attraction between the negatively charged titanium surface and a negatively charged osteoblast is mediated by charged proteins with a distinctive quadrupolar internal charge distribution. Similarly, cation-mediated attraction between fibronectin molecules and the titanium surface is expected to be more efficient for a high surface charge density, resulting in facilitated integrin mediated osteoblast adhesion. We suggest that osteoblasts are most strongly bound along the sharp convex edges or spikes of nanorough titanium surfaces where the magnitude of the negative surface charge density is the highest. It is therefore plausible that nanorough regions of titanium surfaces with sharp edges and spikes promote the adhesion of osteoblasts.Keywords: osteoblasts, nanostructures, adhesion, titanium implants, osteointegration

Receptor for advanced glycation end products inhibits proliferation in osteoblast through suppression of Wnt, PI3K and ERK signaling

International Nuclear Information System (INIS)

Li, Guofeng; Xu, Jingren; Li, Zengchun

2012-01-01

Highlights: ► RAGE overexpression suppresses cell proliferation in MC3T3-E1 cells. ► RAGE overexpression decreases Wnt/β-catenin signaling. ► RAGE overexpression decreases ERK and PI3K signaling. ► Inhibition of Wnt signaling abolishes PI3K signaling restored by RAGE blockade. ► Inhibition of Wnt signaling abolishes ERK signaling restored by RAGE blockade. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a crucial role in bone metabolism. However, the role of RAGE in the control of osteoblast proliferation is not yet evaluated. In the present study, we demonstrate that RAGE overexpression inhibits osteoblast proliferation in vitro. The negative regulation of RAGE on cell proliferation results from suppression of Wnt, PI3K and ERK signaling, and is restored by RAGE neutralizing antibody. Prevention of Wnt signaling using Sfrp1 or DKK1 rescues RAGE-decreased PI3K and ERK signaling and cell proliferation, indicating that the altered cell growth in RAGE overexpressing cells is in part secondary to alterations in Wnt signaling. Consistently, RAGE overexpression inhibits the expression of Wnt targets cyclin D1 and c-myc, which is partially reversed by RAGE blockade. Overall, these results suggest that RAGE inhibits osteoblast proliferation via suppression of Wnt, PI3K and ERK signaling, which provides novel mechanisms by which RAGE regulates osteoblast growth.

Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation

International Nuclear Information System (INIS)

Sato, Chieri; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sano, Hajime

2012-01-01

Highlights: ► We investigated the role of S1P signaling for osteoblast differentiation. ► Both S1P and FTY enhanced BMP-2-stimulated osteoblast differentiation by C2C12 cells. ► S1P signaling enhanced BMP-2-stimulated Smad and ERK phosphorylation by C2C12 cells. ► MEK/ERK signaling is a pathway underlying S1P signaling for osteoblast differentiation. -- Abstract: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P receptor-mediated signaling plays a crucial role for osteoblast differentiation.

Canonical Wnt signaling in differentiated osteoblasts controls osteoclast differentiation.

NARCIS (Netherlands)

Glass, D.A.; Bialek, P.; Ahn, J.D.; Starbuck, M.; Patel, M.S.; Clevers, J.C.; Taketo, M.M.; Long, F.; McMahon, A.P.; Lang, R.A.; Karsenty, G.

2005-01-01

Inactivation of beta-catenin in mesenchymal progenitors prevents osteoblast differentiation; inactivation of Lrp5, a gene encoding a likely Wnt coreceptor, results in low bone mass (osteopenia) by decreasing bone formation. These observations indicate that Wnt signaling controls osteoblast

Understanding magnetic nanoparticle osteoblast receptor-mediated endocytosis using experiments and modeling

International Nuclear Information System (INIS)

Tran, Nhiem; Webster, Thomas J

2013-01-01

Iron oxide nanoparticles are promising candidates for controlling drug delivery through an external magnetic force to treat a wide range of diseases, including osteoporosis. Previous studies have demonstrated that in the presence of hydroxyapatite coated magnetite (Fe 3 O 4 ) nanoparticles, osteoblast (or bone forming cell) proliferation and long-term functions (such as calcium deposition) were significantly enhanced. Hydroxyapatite is the major inorganic component of bone. As a further attempt to understand why, in the current study, the uptake of such nanoparticles into osteoblasts was experimentally investigated and mathematically modeled. Magnetite nanoparticles were synthesized using a co-precipitation method and were coated with hydroxyapatite. A cellular uptake experiment at low temperatures indicated that receptor-mediated endocytosis contributed to the internalization of the magnetic nanoparticles into osteoblasts. A model was further developed to explain the uptake of magnetic nanoparticles into osteoblasts using receptor-mediated endocytosis. This model may explain the internalization of hydroxyapatite into osteoblasts to elevate intracellular calcium levels necessary to promote osteoblast functions to treat a wide range of orthopedic problems, including osteoporosis. (paper)

Calcium homestasis markers of bone metabolism in feline hyperthyroidism - A review

OpenAIRE

Cardoso, M. J L; Muniz, L. M R [UNESP; Gasparini, T. J.; Melussi, M.

2007-01-01

Hyperthyroidism is the most frequent endocrine disease in old-aged cats. It is a illness provoked by the excess of circulating thyroid hormones. Hyperthyroidism causes alteration in bone metabolism with predominance of activity resorption. The evaluation of bone metabolism can be made by measuring serum and urinary markers of bone metabolism or bone mineral densitometry. Osteoblasts are responsible cells for bone formation while the osteoclasts are for resorption. In physiological situation o...

Curcumin induces osteoblast differentiation through mild-endoplasmic reticulum stress-mediated such as BMP2 on osteoblast cells.

Science.gov (United States)

Son, Hyo-Eun; Kim, Eun-Jung; Jang, Won-Gu

2018-01-15

Curcumin (diferuloylmethane or [1E,6E]-1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6heptadiene-3,5-dione) is a phenolic natural product derived from the rhizomes of the turmeric plant, Curcuma longa. It is reported to have various biological actions such as anti-oxidative, anti-inflammatory, and anti-cancer effects. However, the molecular mechanism of osteoblast differentiation by curcumin has not yet been reported. The cytotoxicity of curcumin was identified using the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of osteogenic markers and endoplasmic reticulum (ER) stress markers in C3H1-T1/2 cells were measured using reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blotting. Alkaline phosphatase (ALP) staining was performed to assess ALP activity in C3H10T1/2 cells. Transcriptional activity was detected using a luciferase reporter assay. Curcumin increased the expression of genes such as distal-less homeobox 5 (Dlx5), runt-related transcription factor 2 (Runx2), ALP, and osteocalcin (OC), which subsequently induced osteoblast differentiation in C3H10T1/2 cells. In addition, ALP activity and mineralization was found to be increased by curcumin treatment. Curcumin also induced mild ER stress similar to bone morphogenetic protein 2 (BMP2) function in osteoblast cells. Next, we confirmed that curcumin increased mild ER stress and osteoblast differentiation similar to BMP2 in C3H10T1/2 mesenchymal stem cells. Transient transfection studies also showed that curcumin increased ATF6-Luc activity, while decreasing the activities of CREBH-Luc and SMILE-Luc. In addition, similar to BMP2, curcumin induced the phosphorylation of Smad 1/5/9. Overall, these results demonstrate that curcumin-induced mild ER stress increases osteoblast differentiation via ATF6 expression in C3H10T1/2 cells. Copyright © 2017. Published by Elsevier Inc.

Integrin αv in the mechanical response of osteoblast lineage cells

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Keiko [Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511 (Japan); Ito, Masako [Medical Work-Life-Balance Center, Nagasaki University Hospital, Nagasaki 852-8501 (Japan); Naoe, Yoshinori [Department of Mechanism of Aging, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511 (Japan); Lacy-Hulbert, Adam [Department of Pediatrics, Massachusetts General Hospital, Boston, MA 02114 (United States); Ikeda, Kyoji, E-mail: kikeda@ncgg.go.jp [Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Aichi 474-8511 (Japan)

2014-05-02

Highlights: • Deletion of integrin αv in osteoblast lineage results in an impaired SOST response to loading in vivo. • c-Src–p130Cas–JNK–YAP/TAZ is activated via integrin αv on osteoblasts in response to FSS. • Deletion of integrin αv in osteoblasts results in impaired responses to mechanical stimulation. • Integrin αv is a key component of the mechanosensing machinery in bone. - Abstract: Although osteoblast lineage cells, especially osteocytes, are thought to be a primary mechanosensory cell in bone, the identity of the mechano-receptor and downstream mechano-signaling pathways remain largely unknown. Here we show using osteoblastic cell model of mechanical stimulation with fluid shear stress that in the absence of integrin αv, phosphorylation of the Src substrate p130Cas and JNK was impaired, culminating in an inhibition of nuclear translocation of YAP/TAZ and subsequent transcriptional activation of target genes. Targeted deletion of the integrin αv in osteoblast lineage cells results in an attenuated response to mechanical loading in terms of Sost gene expression, indicative of a role for integrin αv in mechanoreception in vivo. Thus, integrin αv may be integral to a mechanosensing machinery in osteoblastic cells and involved in activation of a Src–JNK–YAP/TAZ pathway in response to mechanical stimulation.

Integrin αv in the mechanical response of osteoblast lineage cells

International Nuclear Information System (INIS)

Kaneko, Keiko; Ito, Masako; Naoe, Yoshinori; Lacy-Hulbert, Adam; Ikeda, Kyoji

2014-01-01

Highlights: • Deletion of integrin αv in osteoblast lineage results in an impaired SOST response to loading in vivo. • c-Src–p130Cas–JNK–YAP/TAZ is activated via integrin αv on osteoblasts in response to FSS. • Deletion of integrin αv in osteoblasts results in impaired responses to mechanical stimulation. • Integrin αv is a key component of the mechanosensing machinery in bone. - Abstract: Although osteoblast lineage cells, especially osteocytes, are thought to be a primary mechanosensory cell in bone, the identity of the mechano-receptor and downstream mechano-signaling pathways remain largely unknown. Here we show using osteoblastic cell model of mechanical stimulation with fluid shear stress that in the absence of integrin αv, phosphorylation of the Src substrate p130Cas and JNK was impaired, culminating in an inhibition of nuclear translocation of YAP/TAZ and subsequent transcriptional activation of target genes. Targeted deletion of the integrin αv in osteoblast lineage cells results in an attenuated response to mechanical loading in terms of Sost gene expression, indicative of a role for integrin αv in mechanoreception in vivo. Thus, integrin αv may be integral to a mechanosensing machinery in osteoblastic cells and involved in activation of a Src–JNK–YAP/TAZ pathway in response to mechanical stimulation

Reduced proliferation and osteocalcin expression in osteoblasts of male idiopathic osteoporosis.

Science.gov (United States)

Ruiz-Gaspà, Sílvia; Blanch-Rubió, Josep; Ciria-Recasens, Manuel; Monfort, Jordi; Tío, Laura; Garcia-Giralt, Natàlia; Nogués, Xavier; Monllau, Joan C; Carbonell-Abelló, Jordi; Pérez-Edo, Lluis

2010-03-01

Osteoporosis is characterized by low bone mineral density (BMD), resulting in increasing susceptibility to bone fractures. In men, it has been related to some diseases and toxic habits, but in some instances the cause of the primary--or idiopathic--osteoporosis is not apparent. In a previous study, our group compared histomorphometric measurements in cortical and cancellous bones from male idiopathic osteoporosis (MIO) patients to those of control subjects and found reduced bone formation without major differences in bone resorption. To confirm these results, this study analyzed the etiology of this pathology, examining the osteoblast behavior in vitro. We compared two parameters of osteoblast activity in MIO patients and controls: osteoblastic proliferation and gene expression of COL1A1 and osteocalcin, in basal conditions and with vitamin D(3) added. All these experiments were performed from a first-passage osteoblastic culture, obtained from osteoblasts that had migrated from the transiliac explants to the plate. The results suggested that the MIO osteoblast has a slower proliferation rate and decreased expression of genes related to matrix formation, probably due to a lesser or slower response to some stimulus. We concluded that, contrary to female osteoporosis, in which loss of BMD is predominantly due to increased resorption, low BMD in MIO seems to be due to an osteoblastic defect.

MSM enhances GH signaling via the Jak2/STAT5b pathway in osteoblast-like cells and osteoblast differentiation through the activation of STAT5b in MSCs.

Directory of Open Access Journals (Sweden)

Youn Hee Joung

Full Text Available Methylsulfonylmethane (MSM is a naturally occurring sulfur compound with well-known anti-oxidant properties and anti-inflammatory activities. But, its effects on bone are unknown. Growth hormone (GH is regulator of bone growth and bone metabolism. GH activates several signaling pathways such as the Janus kinase (Jak/signal transducers and activators of transcription (STAT pathway, thereby regulating expression of genes including insulin-like growth factor (IGF-1. GH exerts effects both directly and via IGF-1, which signals by activating the IGF-1 receptor (IGF-1R. In this study, we investigated the effects of MSM on the GH signaling via the Jak/STAT pathway in osteoblasts and the differentiation of primary bone marrow mesenchymal stem cells (MSCs. MSM was not toxic to osteoblastic cells and MSCs. MSM increased the expression of GH-related proteins including IGF-1R, p-IGF-1R, STAT5b, p-STAT5b, and Jak2 in osteoblastic cells and MSCs. MSM increased IGF-1R and GHR mRNA expression in osteoblastic cells. The expression of MSM-induced IGF-1R and GHR was inhibited by AG490, a Jak2 kinase inhibitor. MSM induced binding of STAT5 to the IGF-1R and increased IGF-1 and IGF-1R promoter activities. Analysis of cell extracts by immunoprecipitation and Western blot showed that MSM enhanced GH-induced activation of Jak2/STAT5b. We found that MSM and GH, separately or in combination, activated GH signaling via the Jak2/STAT5b pathway in UMR-106 cells. Using siRNA analysis, we found that STAT5b plays an essential role in GH signaling activation in C3H10T1/2 cells. Osteogenic marker genes (ALP, ON, OCN, BSP, OSX, and Runx2 were activated by MSM, and siRNA-mediated STAT5b knockdown inhibited MSM-induced expression of osteogenic markers. Furthermore, MSM increased ALP activity and the mineralization of MSCs. Taken together, these results indicated that MSM can promote osteogenic differentiation of MSCs through activation of STAT5b.

ADA-deficient SCID is associated with a specific microenvironment and bone phenotype characterized by RANKL/OPG imbalance and osteoblast insufficiency.

Science.gov (United States)

Sauer, Aisha V; Mrak, Emanuela; Hernandez, Raisa Jofra; Zacchi, Elena; Cavani, Francesco; Casiraghi, Miriam; Grunebaum, Eyal; Roifman, Chaim M; Cervi, Maria C; Ambrosi, Alessandro; Carlucci, Filippo; Roncarolo, Maria Grazia; Villa, Anna; Rubinacci, Alessandro; Aiuti, Alessandro

2009-10-08

Adenosine deaminase (ADA) deficiency is a disorder of the purine metabolism leading to combined immunodeficiency and systemic alterations, including skeletal abnormalities. We report that ADA deficiency in mice causes a specific bone phenotype characterized by alterations of structural properties and impaired mechanical competence. These alterations are the combined result of an imbalanced receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoprotegerin axis, causing decreased osteoclastogenesis and an intrinsic defect of osteoblast function with subsequent low bone formation. In vitro, osteoblasts lacking ADA displayed an altered transcriptional profile and growth reduction. Furthermore, the bone marrow microenvironment of ADA-deficient mice showed a reduced capacity to support in vitro and in vivo hematopoiesis. Treatment of ADA-deficient neonatal mice with enzyme replacement therapy, bone marrow transplantation, or gene therapy resulted in full recovery of the altered bone parameters. Remarkably, untreated ADA-severe combined immunodeficiency patients showed a similar imbalance in RANKL/osteoprotegerin levels alongside severe growth retardation. Gene therapy with ADA-transduced hematopoietic stem cells increased serum RANKL levels and children's growth. Our results indicate that the ADA metabolism represents a crucial modulatory factor of bone cell activities and remodeling.

Sphingosine 1-phosphate receptor activation enhances BMP-2-induced osteoblast differentiation

Energy Technology Data Exchange (ETDEWEB)

Sato, Chieri [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Iwasaki, Tsuyoshi, E-mail: tsuyo-i@huhs.ac.jp [Division of Pharmacotherapy, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, 1-3-6 Minatojima, Chuo-ku, Kobe 650-8530 (Japan); Kitano, Sachie; Tsunemi, Sachi; Sano, Hajime [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan)

2012-06-22

Highlights: Black-Right-Pointing-Pointer We investigated the role of S1P signaling for osteoblast differentiation. Black-Right-Pointing-Pointer Both S1P and FTY enhanced BMP-2-stimulated osteoblast differentiation by C2C12 cells. Black-Right-Pointing-Pointer S1P signaling enhanced BMP-2-stimulated Smad and ERK phosphorylation by C2C12 cells. Black-Right-Pointing-Pointer MEK/ERK signaling is a pathway underlying S1P signaling for osteoblast differentiation. -- Abstract: We previously demonstrated that sphingosine 1-phosphate (S1P) receptor-mediated signaling induced proliferation and prostaglandin productions by synovial cells from rheumatoid arthritis (RA) patients. In the present study we investigated the role of S1P receptor-mediated signaling for osteoblast differentiation. We investigated osteoblast differentiation using C2C12 myoblasts, a cell line derived from murine satellite cells. Osteoblast differentiation was induced by the treatment of bone morphogenic protein (BMP)-2 in the presence or absence of either S1P or FTY720 (FTY), a high-affinity agonist of S1P receptors. Osteoblast differentiation was determined by osteoblast-specific transcription factor, Runx2 mRNA expression, alkaline phosphatase (ALP) activity and osteocalcin production by the cells. Smad1/5/8 and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation was examined by Western blotting. Osteocalcin production by C2C12 cells were determined by ELISA. Runx2 expression and ALP activity by BMP-2-stimulated C2C12 cells were enhanced by addition of either S1P or FTY. Both S1P and FTY enhanced BMP-2-induced ERK1/2 and Smad1/5/8 phosphorylation. The effect of FTY was stronger than that of S1P. S1P receptor-mediated signaling on osteoblast differentiation was inhibited by addition of mitogen-activated protein kinase/ERK kinase (MEK) 1/2 inhibitor, indicating that the S1P receptor-mediated MEK1/2-ERK1/2 signaling pathway enhanced BMP-2-Smad signaling. These results indicate that S1P

Seawater Polluted with Highly Concentrated Polycyclic Aromatic Hydrocarbons Suppresses Osteoblastic Activity in the Scales of Goldfish, Carassius auratus.

Science.gov (United States)

Suzuki, Nobuo; Sato, Masayuki; Nassar, Hossam F; Abdel-Gawad, Fagr Kh; Bassem, Samah M; Yachiguchi, Koji; Tabuchi, Yoshiaki; Endo, Masato; Sekiguchi, Toshio; Urata, Makoto; Hattori, Atsuhiko; Mishima, Hiroyuki; Shimasaki, Youhei; Oshima, Yuji; Hong, Chun-Sang; Makino, Fumiya; Tang, Ning; Toriba, Akira; Hayakawa, Kazuichi

2016-08-01

We have developed an original in vitro bioassay using teleost scale, that has osteoclasts, osteoblasts, and bone matrix as each marker: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Using this scale in vitro bioassay, we examined the effects of seawater polluted with highly concentrated polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) on osteoblastic and osteoclastic activities in the present study. Polluted seawater was collected from two sites (the Alexandria site on the Mediterranean Sea and the Suez Canal site on the Red Sea). Total levels of PAHs in the seawater from the Alexandria and Suez Canal sites were 1364.59 and 992.56 ng/l, respectively. We were able to detect NPAHs in both seawater samples. Total levels of NPAHs were detected in the seawater of the Alexandria site (12.749 ng/l) and the Suez Canal site (3.914 ng/l). Each sample of polluted seawater was added to culture medium at dilution rates of 50, 100, and 500, and incubated with the goldfish scales for 6 hrs. Thereafter, ALP and TRAP activities were measured. ALP activity was significantly suppressed by both polluted seawater samples diluted at least 500 times, but TRAP activity did not change. In addition, mRNA expressions of osteoblastic markers (ALP, osteocalcin, and the receptor activator of the NF-κB ligand) decreased significantly, as did the ALP enzyme activity. In fact, ALP activity decreased on treatment with PAHs and NPAHs. We conclude that seawater polluted with highly concentrated PAHs and NPAHs influences bone metabolism in teleosts.

Transdifferentiation of adipocytes to osteoblasts: potential for orthopaedic treatment.

Science.gov (United States)

Lin, Daphne P L; Dass, Crispin R

2018-03-01

As both adipocytes and osteoblasts originate from the same pool of mesenchymal stem cells, increasing clinical evidence has emerged of the plasticity between the two lineages. For instance, the downregulation of osteoblast differentiation and upregulation of adipogenesis are common features of conditions such as multiple myeloma, obesity and drug-induced bone loss in diabetes mellitus. However, despite in-vitro and in-vivo observations of adipocyte transdifferentiation into osteoblasts, little is known of the underlying mechanisms. This review summarises the current knowledge of this particular transdifferentiation process whereby the Wnt/β-catenin signalling pathway and Runx2 overexpression have been postulated to play a critical role. Furthermore, due to the possibility of a novel therapy in the treatment of bone conditions, a number of agents with the potential to induce adipo-to-osteoblast transdifferentiation have been investigated such as all-trans retinoic acid, bone morphogenetic protein-9 and vascular endothelial growth factor. © 2018 Royal Pharmaceutical Society.

Osteoblast-targeted overexpression of TAZ increases bone mass in vivo.

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Jae-Yeon Yang

Full Text Available Osteoblasts are derived from mesenchymal progenitors. Differentiation to osteoblasts and adipocytes is reciprocally regulated. Transcriptional coactivator with a PDZ-binding motif (TAZ is a transcriptional coactivator that induces differentiation of mesenchymal cells into osteoblasts while blocking differentiation into adipocytes. To investigate the role of TAZ on bone metabolism in vivo, we generated transgenic mice that overexpress TAZ under the control of the procollagen type 1 promoter (Col1-TAZ. Whole body bone mineral density (BMD of 6- to 19-week-old Col-TAZ mice was 4% to 7% higher than that of their wild-type (WT littermates, whereas no difference was noticed in Col.1-TAZ female mice. Microcomputed tomography analyses of proximal tibiae at 16 weeks of age demonstrated a significant increase in trabecular bone volume (26.7% and trabecular number (26.6% with a reciprocal decrease in trabecular spacing (14.2% in Col1-TAZ mice compared with their WT littermates. In addition, dynamic histomorphometric analysis of the lumbar spine revealed increased mineral apposition rate (42.8% and the serum P1NP level was also significantly increased (53% in Col.1-TAZ mice. When primary calvaria cells were cultured in osteogenic medium, alkaline phosphatase (ALP activity was significantly increased and adipogenesis was significantly suppressed in Col1-TAZ mice compared with their WT littermates. Quantitative real-time polymerase chain reaction analyses showed that expression of collagen type 1, bone sialoprotein, osteocalcin, ALP, osterix, and Runx2 was significantly increased in calvaria cells from Col1-TAZ mice compared to their WT littermates. In vitro, TAZ enhanced Runx2-mediated transcriptional activity while suppressing the peroxisome proliferator-activated receptor gamma signaling pathway. TAZ also enhanced transcriptional activity from 3TP-Lux, which reflects transforming growth factor-beta (TGF-β-mediated signaling. In addition, TAZ enhanced TGF

Factors circulating in the blood of type 2 diabetes mellitus patients affect osteoblast maturation – Description of a novel in vitro model

International Nuclear Information System (INIS)

Ehnert, Sabrina; Freude, Thomas; Ihle, Christoph; Mayer, Larissa; Braun, Bianca; Graeser, Jessica; Flesch, Ingo

2015-01-01

Type 2 diabetes mellitus (T2DM) is one of the most frequent metabolic disorders in industrialized countries. Among other complications, T2DM patients have an increased fracture risk and delayed fracture healing. We have demonstrated that supraphysiological glucose and insulin levels inhibit primary human osteoblasts' maturation. We aimed at developing a more physiologically relevant in vitro model to analyze T2DM-mediated osteoblast changes. Therefore, SCP-1-immortalized pre-osteoblasts were differentiated with T2DM or control (non-obese and obese) sera. Between both control groups, no significant changes were observed. Proliferation was significantly increased (1.69-fold), while AP activity and matrix mineralization was significantly reduced in the T2DM group. Expression levels of osteogenic marker genes and transcription factors were altered, e.g. down-regulation of RUNX2 and SP-7 or up-regulation of STAT1, in the T2DM group. Active TGF-β levels were significantly increased (1.46-fold) in T2DM patients' sera. SCP-1 cells treated with these sera showed significantly increased TGF-β signaling (2.47-fold). Signaling inhibition effectively restored osteoblast maturation in the T2DM group. Summarizing our data, SCP-1 cells differentiated in the presence of T2DM patients' serum exhibit reduced osteoblast function. Thus, this model has a high physiological impact, as it can identify circulating factors in T2DM patients' blood that may affect bone function, e.g. TGF-β. - Highlights: • We present here a physiologically relevant in vitro model for diabetic osteopathy. • Blood of T2DM patients contains factors that affect osteoblasts' function. • The model developed here can be used to identify these factors, e.g. TGF-β. • Blocking TGF-β signaling partly rescues the osteoblasts' function in the T2DM group. • The model is useful to demonstrate the role of single factors in diabetic osteopathy

Factors circulating in the blood of type 2 diabetes mellitus patients affect osteoblast maturation – Description of a novel in vitro model

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Ehnert, Sabrina, E-mail: sabrina.ehnert@gmail.com [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Freude, Thomas, E-mail: tfreude@bgu-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Ihle, Christoph, E-mail: cihle@bgu-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Mayer, Larissa, E-mail: lara.nk@gmail.com [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Braun, Bianca, E-mail: bianca.braun@med.uni-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Graeser, Jessica, E-mail: jessica.graeser@student.reutlingen-university.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); Flesch, Ingo, E-mail: iflesch@bgu-tuebingen.de [BG Trauma Center, Eberhard Karls Universität Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen (Germany); and others

2015-03-15

Type 2 diabetes mellitus (T2DM) is one of the most frequent metabolic disorders in industrialized countries. Among other complications, T2DM patients have an increased fracture risk and delayed fracture healing. We have demonstrated that supraphysiological glucose and insulin levels inhibit primary human osteoblasts' maturation. We aimed at developing a more physiologically relevant in vitro model to analyze T2DM-mediated osteoblast changes. Therefore, SCP-1-immortalized pre-osteoblasts were differentiated with T2DM or control (non-obese and obese) sera. Between both control groups, no significant changes were observed. Proliferation was significantly increased (1.69-fold), while AP activity and matrix mineralization was significantly reduced in the T2DM group. Expression levels of osteogenic marker genes and transcription factors were altered, e.g. down-regulation of RUNX2 and SP-7 or up-regulation of STAT1, in the T2DM group. Active TGF-β levels were significantly increased (1.46-fold) in T2DM patients' sera. SCP-1 cells treated with these sera showed significantly increased TGF-β signaling (2.47-fold). Signaling inhibition effectively restored osteoblast maturation in the T2DM group. Summarizing our data, SCP-1 cells differentiated in the presence of T2DM patients' serum exhibit reduced osteoblast function. Thus, this model has a high physiological impact, as it can identify circulating factors in T2DM patients' blood that may affect bone function, e.g. TGF-β. - Highlights: • We present here a physiologically relevant in vitro model for diabetic osteopathy. • Blood of T2DM patients contains factors that affect osteoblasts' function. • The model developed here can be used to identify these factors, e.g. TGF-β. • Blocking TGF-β signaling partly rescues the osteoblasts' function in the T2DM group. • The model is useful to demonstrate the role of single factors in diabetic osteopathy.

Responses of human normal osteoblast cells and osteoblast-like cell line, MG-63 cells, to pulse electromagnetic field (PEMF

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Suttatip Kamolmatyakul

2008-01-01

Full Text Available The objective of this in vitro study is to investigate the effect of pulsed electromagnetic field (PEMF on cellular proliferation and osteocalcin production of osteoblast-like cell line, MG-63 cells, and human normal osteoblast cells (NHOC obtained from surgical bone specimens. The cells were placed in 24-well culture plates in the amount of 3x104 cell/wells with 2 ml αMEM media supplemented with 10% FBS. The experimental plates were placed between a pair of Helmoltz coils powered by a pulse generator (PEMF, 50 Hz, 1.5 mV/cm in the upper compartment of a dual incubator (Forma. The control plates were placed in the lower compartment of the incubator without Helmotz coils. After three days, the cell proliferation was measured by the method modified from Mossman (J. Immunol Methods 1983; 65: 55-63. Other sets of plates were used for osteocalcin production assessment. Media from these sets were collected after 6 days and assessed for osteocalcin production using ELISA kits. The data were analyzed using a one-way analysis of variance (ANOVA. The results showed that MG-63 cells from the experimental group proliferated significantly more than those from the control group (20% increase, p<0.05. No significant difference in osteocalcin production was detected between the two groups. On the other hand, NHOC from the experimental group produced larger amount of osteocalcin (25% increase, p<0.05 and proliferated significantly more than those from the control group (100% increase, p<0.05. In conclusion, PEMF effect on osteoblasts might depend on their cell type of origin. For osteoblast-like cell line, MG-63 cells, PEMF increased proliferation rate but not osteocalcin production of the cells. However, PEMF stimulation effect on human normal osteoblast cells was most likely associated with enhancement of both osteocalcin production and cell proliferation.

Phenolic Compounds in Extra Virgin Olive Oil Stimulate Human Osteoblastic Cell Proliferation.

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García-Martínez, Olga; De Luna-Bertos, Elvira; Ramos-Torrecillas, Javier; Ruiz, Concepción; Milia, Egle; Lorenzo, María Luisa; Jimenez, Brigida; Sánchez-Ortiz, Araceli; Rivas, Ana

2016-01-01

In this study, we aimed to clarify the effects of phenolic compounds and extracts from different extra virgin olive oil (EVOO) varieties obtained from fruits of different ripening stages on osteoblast cells (MG-63) proliferation. Cell proliferation was increased by hydroxytyrosol, luteolin, apigenin, p-coumaric, caffeic, and ferulic acids by approximately 11-16%, as compared with controls that were treated with one vehicle alone, while (+)-pinoresinol, oleuropein, sinapic, vanillic acid and derivative (vanillin) did not affect cell proliferation. All phenolic extracts stimulated MG-63 cell growth, and they induced higher cell proliferation rates than individual compounds. The most effective EVOO phenolic extracts were those obtained from the Picual variety, as they significantly increased cell proliferation by 18-22%. Conversely, Arbequina phenolic extracts increased cell proliferation by 9-13%. A decline in osteoblast proliferation was observed in oils obtained from olive fruits collected at the end of the harvest period, as their total phenolic content decreases at this late stage. Further research on the signaling pathways of olive oil phenolic compounds involved in the processes and their metabolism should be carried out to develop new interventions and adjuvant therapies using EVOO for bone health (i.e.osteoporosis) in adulthood and the elderly.

Phenolic Compounds in Extra Virgin Olive Oil Stimulate Human Osteoblastic Cell Proliferation

Science.gov (United States)

García-Martínez, Olga; De Luna-Bertos, Elvira; Ramos-Torrecillas, Javier; Ruiz, Concepción; Milia, Egle; Lorenzo, María Luisa; Jimenez, Brigida; Sánchez-Ortiz, Araceli; Rivas, Ana

2016-01-01

In this study, we aimed to clarify the effects of phenolic compounds and extracts from different extra virgin olive oil (EVOO) varieties obtained from fruits of different ripening stages on osteoblast cells (MG-63) proliferation. Cell proliferation was increased by hydroxytyrosol, luteolin, apigenin, p-coumaric, caffeic, and ferulic acids by approximately 11–16%, as compared with controls that were treated with one vehicle alone, while (+)-pinoresinol, oleuropein, sinapic, vanillic acid and derivative (vanillin) did not affect cell proliferation. All phenolic extracts stimulated MG-63 cell growth, and they induced higher cell proliferation rates than individual compounds. The most effective EVOO phenolic extracts were those obtained from the Picual variety, as they significantly increased cell proliferation by 18–22%. Conversely, Arbequina phenolic extracts increased cell proliferation by 9–13%. A decline in osteoblast proliferation was observed in oils obtained from olive fruits collected at the end of the harvest period, as their total phenolic content decreases at this late stage. Further research on the signaling pathways of olive oil phenolic compounds involved in the processes and their metabolism should be carried out to develop new interventions and adjuvant therapies using EVOO for bone health (i.e.osteoporosis) in adulthood and the elderly. PMID:26930190

Gene profile analysis of osteoblast genes differentially regulated by histone deacetylase inhibitors

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Lamblin Anne-Francoise

2007-10-01

Full Text Available Abstract Background Osteoblast differentiation requires the coordinated stepwise expression of multiple genes. Histone deacetylase inhibitors (HDIs accelerate the osteoblast differentiation process by blocking the activity of histone deacetylases (HDACs, which alter gene expression by modifying chromatin structure. We previously demonstrated that HDIs and HDAC3 shRNAs accelerate matrix mineralization and the expression of osteoblast maturation genes (e.g. alkaline phosphatase, osteocalcin. Identifying other genes that are differentially regulated by HDIs might identify new pathways that contribute to osteoblast differentiation. Results To identify other osteoblast genes that are altered early by HDIs, we incubated MC3T3-E1 preosteoblasts with HDIs (trichostatin A, MS-275, or valproic acid for 18 hours in osteogenic conditions. The promotion of osteoblast differentiation by HDIs in this experiment was confirmed by osteogenic assays. Gene expression profiles relative to vehicle-treated cells were assessed by microarray analysis with Affymetrix GeneChip 430 2.0 arrays. The regulation of several genes by HDIs in MC3T3-E1 cells and primary osteoblasts was verified by quantitative real-time PCR. Nine genes were differentially regulated by at least two-fold after exposure to each of the three HDIs and six were verified by PCR in osteoblasts. Four of the verified genes (solute carrier family 9 isoform 3 regulator 1 (Slc9a3r1, sorbitol dehydrogenase 1, a kinase anchor protein, and glutathione S-transferase alpha 4 were induced. Two genes (proteasome subunit, beta type 10 and adaptor-related protein complex AP-4 sigma 1 were suppressed. We also identified eight growth factors and growth factor receptor genes that are significantly altered by each of the HDIs, including Frizzled related proteins 1 and 4, which modulate the Wnt signaling pathway. Conclusion This study identifies osteoblast genes that are regulated early by HDIs and indicates pathways that

Effects of space-relevant radiation on pre-osteoblasts

International Nuclear Information System (INIS)

Hu, Yueyuan

2014-01-01

Until now limited research has been conducted to address the mechanisms leading ionizing radiation exposure induced bone loss. This is relevant for cancer radiotherapy and human spaceflight. Exposure to radiation can result in elevated bone fracture risk in patients receiving cancer radiotherapy. In human spaceflight, astronauts are exposed to space radiation which is a very complex mixture consisting primarily of high-energy charged particles. Osteoblasts are of mesenchymal origin and responsible for creating and maintaining skeletal architecture; these cells produce extracellular matrix proteins and regulators of matrix mineralization during initial bone formation and later bone remodeling. The aim of this work was to investigate the effects of ionizing radiation on pre-osteoblasts including cellular survival, cell cycle regulation and differentiation modification. Experiments with the pre-osteoblast cell line OCT-1 and the mesenchymal stem cell line C3H10T1/2 showed that radiation cell killing depends on dose and linear energy transfer (LET) and is most effective at an LET of ∝150 keV/μm. High-LET radiation has a much more pronounced ability to induce cell cycle arrest in the G2/M phase. After both X-rays and heavy ions exposure, expression of the cell cycle regulator CDKN1A was significantly up-regulated in a dose-dependent manner. The findings suggest that cell cycle regulation is more sensitive to high-LET radiation than cell survival, which is not solely regulated through elevated CDKN1A expression. Radiation exposure enhances osteoblastic differentiation and maturation, and mediates Runx2 and TGF-β1 expression during early differentiation of pre-osteoblasts. Osteogenic differentiation did not alter cellular radiosensitivity, DNA repair of radiation-induced damages and the effects of radiation on proliferation. Further experiments are needed to elucidate possible synergistic effects of microgravity and radiation on osteoblast differentiation. This may

Effects of space-relevant radiation on pre-osteoblasts

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Hu, Yueyuan

2014-02-12

Until now limited research has been conducted to address the mechanisms leading ionizing radiation exposure induced bone loss. This is relevant for cancer radiotherapy and human spaceflight. Exposure to radiation can result in elevated bone fracture risk in patients receiving cancer radiotherapy. In human spaceflight, astronauts are exposed to space radiation which is a very complex mixture consisting primarily of high-energy charged particles. Osteoblasts are of mesenchymal origin and responsible for creating and maintaining skeletal architecture; these cells produce extracellular matrix proteins and regulators of matrix mineralization during initial bone formation and later bone remodeling. The aim of this work was to investigate the effects of ionizing radiation on pre-osteoblasts including cellular survival, cell cycle regulation and differentiation modification. Experiments with the pre-osteoblast cell line OCT-1 and the mesenchymal stem cell line C3H10T1/2 showed that radiation cell killing depends on dose and linear energy transfer (LET) and is most effective at an LET of ∝150 keV/μm. High-LET radiation has a much more pronounced ability to induce cell cycle arrest in the G2/M phase. After both X-rays and heavy ions exposure, expression of the cell cycle regulator CDKN1A was significantly up-regulated in a dose-dependent manner. The findings suggest that cell cycle regulation is more sensitive to high-LET radiation than cell survival, which is not solely regulated through elevated CDKN1A expression. Radiation exposure enhances osteoblastic differentiation and maturation, and mediates Runx2 and TGF-β1 expression during early differentiation of pre-osteoblasts. Osteogenic differentiation did not alter cellular radiosensitivity, DNA repair of radiation-induced damages and the effects of radiation on proliferation. Further experiments are needed to elucidate possible synergistic effects of microgravity and radiation on osteoblast differentiation. This may

Adiponectin stimulates human osteoblasts proliferation and differentiation via the MAPK signaling pathway

International Nuclear Information System (INIS)

Luo Xianghang; Guo Lijuan; Yuan Lingqing; Xie Hui; Zhou Houde; Wu Xianping; Liao Eryuan

2005-01-01

Adipocytes can highly and specifically express adiponectin, and the adiponectin receptor (AdipoR) has been detected in bone-forming cells. The present study was undertaken to investigate the action of adiponectin on osteoblast proliferation and differentiation. AdipoR1 protein was detected in human osteoblasts. Adiponectin promoted osteoblast proliferation and resulted in a dose- and time-dependent increase in alkaline phosphatase (ALP) activity, osteocalcin and type I collagen production, and an increase in mineralized matrix. Suppression of AdipoR1 with small-interfering RNA (siRNA) abolished the adiponectin-induced cell proliferation and ALP expression. Adiponectin induces activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal Kinase (JNK), but not ERK1/2 in osteoblasts, and these effects were blocked by suppression of AdipoR1 with siRNA. Furthermore, pretreatment of osteoblasts with the JNK inhibitor SP600125 abolished the adiponectin-induced cell proliferation. p38 inhibitor SB203580 blocked the adiponectin-induced ALP activity. These data indicate that adiponectin induces human osteoblast proliferation and differentiation, and the proliferation response is mediated by the AdipoR/JNK pathway, while the differentiation response is mediated via the AdipoR/p38 pathway. These findings suggest that osteoblasts are the direct targets of adiponectin

Receptor for advanced glycation end products inhibits proliferation in osteoblast through suppression of Wnt, PI3K and ERK signaling

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Li, Guofeng [Department of Emergency Surgery, East Hospital, Tongji University School of Medicine, Shanghai 200120 (China); Xu, Jingren [Department of Traditional Chinese Orthopaedics, East Hospital, Tongji University School of Medicine, Shanghai 200120 (China); Li, Zengchun, E-mail: lizc.2007@yahoo.com.cn [Department of Emergency Surgery, East Hospital, Tongji University School of Medicine, Shanghai 200120 (China)

2012-07-13

Highlights: Black-Right-Pointing-Pointer RAGE overexpression suppresses cell proliferation in MC3T3-E1 cells. Black-Right-Pointing-Pointer RAGE overexpression decreases Wnt/{beta}-catenin signaling. Black-Right-Pointing-Pointer RAGE overexpression decreases ERK and PI3K signaling. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes PI3K signaling restored by RAGE blockade. Black-Right-Pointing-Pointer Inhibition of Wnt signaling abolishes ERK signaling restored by RAGE blockade. -- Abstract: Expression of receptor for advanced glycation end products (RAGE) plays a crucial role in bone metabolism. However, the role of RAGE in the control of osteoblast proliferation is not yet evaluated. In the present study, we demonstrate that RAGE overexpression inhibits osteoblast proliferation in vitro. The negative regulation of RAGE on cell proliferation results from suppression of Wnt, PI3K and ERK signaling, and is restored by RAGE neutralizing antibody. Prevention of Wnt signaling using Sfrp1 or DKK1 rescues RAGE-decreased PI3K and ERK signaling and cell proliferation, indicating that the altered cell growth in RAGE overexpressing cells is in part secondary to alterations in Wnt signaling. Consistently, RAGE overexpression inhibits the expression of Wnt targets cyclin D1 and c-myc, which is partially reversed by RAGE blockade. Overall, these results suggest that RAGE inhibits osteoblast proliferation via suppression of Wnt, PI3K and ERK signaling, which provides novel mechanisms by which RAGE regulates osteoblast growth.

Expression and Dynamics of Podoplanin in Cultured Osteoblasts with Mechanostress and Mineralization Stimulus.

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Takenawa, Tomohiro; Kanai, Takenori; Kitamura, Tetsuya; Yoshimura, Yoshitaka; Sawa, Yoshihiko; Iida, Junichiro

2018-02-27

This study investigates the significance of the expression and dynamics of podoplanin in mechanostress and mineralization in cultured murine osteoblasts. Podoplanin increased in osteoblasts subjected to straining in non-mineralization medium, suggesting that the mechanostress alone is a podoplanin induction factor. In osteoblasts subjected to vertical elongation straining in the mineralization medium, the mRNA amounts of podoplanin, osteopontin, and osteocalcin were significantly larger than those in cells not subjected to straining, suggesting that mechanostress is the cause of a synergistic effect in the expression of these proteins. In osteoblasts in the mineralization medium, significant increases in osteocalcin mRNA occurred earlier in cells subjected to straining than in the cells not subjected to straining, suggesting that the mechanostress is a critical factor to enhance the expression of osteocalcin. Western blot and ELISA analysis showed increased podoplanin production in osteoblasts with longer durations of straining. There was significantly less mineralization product in osteoblasts with antibodies for podoplanin, osteopontin, and osteocalcin. There was also less osteopontin and osteocalcin produced in osteoblasts with anti-podoplanin. These findings suggest that mechanostress induces the production of podoplanin in osteoblasts and that podoplanin may play a role in mineralization in cooperation with bone-associated proteins.

Osteoblast Differentiation and Bone Matrix Formation In Vivo and In Vitro.

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Blair, Harry C; Larrouture, Quitterie C; Li, Yanan; Lin, Hang; Beer-Stoltz, Donna; Liu, Li; Tuan, Rocky S; Robinson, Lisa J; Schlesinger, Paul H; Nelson, Deborah J

2017-06-01

We review the characteristics of osteoblast differentiation and bone matrix synthesis. Bone in air breathing vertebrates is a specialized tissue that developmentally replaces simpler solid tissues, usually cartilage. Bone is a living organ bounded by a layer of osteoblasts that, because of transport and compartmentalization requirements, produce bone matrix exclusively as an organized tight epithelium. With matrix growth, osteoblasts are reorganized and incorporated into the matrix as living cells, osteocytes, which communicate with each other and surface epithelium by cell processes within canaliculi in the matrix. The osteoblasts secrete the organic matrix, which are dense collagen layers that alternate parallel and orthogonal to the axis of stress loading. Into this matrix is deposited extremely dense hydroxyapatite-based mineral driven by both active and passive transport and pH control. As the matrix matures, hydroxyapatite microcrystals are organized into a sophisticated composite in the collagen layer by nucleation in the protein lattice. Recent studies on differentiating osteoblast precursors revealed a sophisticated proton export network driving mineralization, a gene expression program organized with the compartmentalization of the osteoblast epithelium that produces the mature bone matrix composite, despite varying serum calcium and phosphate. Key issues not well defined include how new osteoblasts are incorporated in the epithelial layer, replacing those incorporated in the accumulating matrix. Development of bone in vitro is the subject of numerous projects using various matrices and mesenchymal stem cell-derived preparations in bioreactors. These preparations reflect the structure of bone to variable extents, and include cells at many different stages of differentiation. Major challenges are production of bone matrix approaching the in vivo density and support for trabecular bone formation. In vitro differentiation is limited by the organization and

Nanostructured magnesium has fewer detrimental effects on osteoblast function

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Weng L

2013-05-01

Full Text Available Lucy Weng, Thomas J Webster School of Engineering and Department of Orthopedics, Brown University, Providence, RI, USA Abstract: Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells. Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications. Keywords: nanostructured magnesium, degradation, detrimental effects, osteoblasts

Effects of different magnitudes of mechanical strain on Osteoblasts in vitro

International Nuclear Information System (INIS)

Tang Lin; Lin Zhu; Li Yongming

2006-01-01

In addition to systemic and local factors, mechanical strain plays a crucial role in bone remodeling during growth, development, and fracture healing, and especially in orthodontic tooth movement. Although many papers have been published on the effects of mechanical stress on osteoblasts or osteoblastic cells, little is known about the effects of different magnitudes of mechanical strain on such cells. In the present study, we investigated how different magnitudes of cyclic tensile strain affected osteoblasts. MC3T3-E1 osteoblastic cells were subjected to 0%, 6%, 12% or 18% elongation for 24 h using a Flexercell Strain Unit, and then the mRNA and protein expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) were examined. The results showed that cyclic tensile strain induced a magnitude-dependent increase (0%, 6%, 12%, and 18%) in OPG synthesis and a concomitant decrease in RANKL mRNA expression and sRANKL release from the osteoblasts. Furthermore, the induction of OPG mRNA expression by stretching was inhibited by indomethacin or genistein, and the stretch-induced reduction of RANKL mRNA was inhibited by PD098059. These results indicate that different magnitudes of cyclic tensile strain influence the biological behavior of osteoblasts, which profoundly affects bone remodeling

Adiponectin and AMP kinase activator stimulate proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells

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Yamauchi Mika

2007-11-01

Full Text Available Abstract Background Adiponectin is a key mediator of the metabolic syndrome that is caused by visceral fat accumulation. Adiponectin and its receptors are known to be expressed in osteoblasts, but their actions with regard to bone metabolism are still unclear. In this study, we investigated the effects of adiponectin on the proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells. Results Adiponectin receptor type 1 (AdipoR1 mRNA was detected in the cells by RT-PCR. The adenosine monophosphate-activated protein kinase (AMP kinase was phosphorylated by both adiponectin and a pharmacological AMP kinase activator, 5-amino-imidazole-4-carboxamide-riboside (AICAR, in the cells. AdipoR1 small interfering RNA (siRNA transfection potently knocked down the receptor mRNA, and the effect of this knockdown persisted for as long as 10 days after the transfection. The transfected cells showed decreased expressions of type I collagen and osteocalcin mRNA, as determined by real-time PCR, and reduced ALP activity and mineralization, as determined by von Kossa and Alizarin red stainings. In contrast, AMP kinase activation by AICAR (0.01–0.5 mM in wild-type MC3T3-E1 cells augmented their proliferation, differentiation, and mineralization. BrdU assay showed that the addition of adiponectin (0.01–1.0 μg/ml also promoted their proliferation. Osterix, but not Runx-2, appeared to be involved in these processes because AdipoR1 siRNA transfection and AICAR treatments suppressed and enhanced osterix mRNA expression, respectively. Conclusion Taken together, this study suggests that adiponectin stimulates the proliferation, differentiation, and mineralization of osteoblasts via the AdipoR1 and AMP kinase signaling pathways in autocrine and/or paracrine fashions.

Smurf1 Inhibits Osteoblast Differentiation, Bone Formation, and Glucose Homeostasis through Serine 148

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Junko Shimazu

2016-04-01

Full Text Available The E3 ubiquitin ligase Smurf1 targets the master regulator of osteoblast differentiation, Runx2, for degradation, yet the function of Smurf1, if any, during osteoblast differentiation in vivo is ill defined. Here, we show that Smurf1 prevents osteoblast differentiation by decreasing Runx2 accumulation in osteoblasts. Remarkably, mice harboring a substitution mutation at serine 148 (S148 in Smurf1 that prevents its phosphorylation by AMPK (Smurf1ki/ki display a premature osteoblast differentiation phenotype that is equally severe as that of Smurf1−/− mice, as well as a high bone mass, and are also hyperinsulinemic and hypoglycemic. Consistent with the fact that Smurf1 targets the insulin receptor for degradation, there is, in Smurf1ki/ki mice, an increase in insulin signaling in osteoblasts that triggers a rise in the circulating levels of osteocalcin, a hormone that favors insulin secretion. These results identify Smurf1 as a determinant of osteoblast differentiation during the development of bone formation and glucose homeostasis post-natally and demonstrate the necessity of S148 for these functions.

Notch Signaling in Prostate Cancer Cells Promotes Osteoblastic Metastasis

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2017-06-01

information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this...function and number while inducing osteoblast proliferation. Our results suggest that Notch signaling from cancer cells promotes osteoblastic...Participants and other collaborating organizations: I initiated collaboration with Dr. Evan Keller at University of Michigan to interrogate PCa bone

Osteoblasts Protect AML Cells from SDF-1-Induced Apoptosis

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Kremer, Kimberly N.; Dudakovic, Amel; McGee-Lawrence, Meghan E.; Philips, Rachael L.; Hess, Allan D.; Smith, B. Douglas; van Wijnen, Andre J.; Karp, Judith E.; Kaufmann, Scott H.; Westendorf, Jennifer J.; Hedin, Karen E.

2014-01-01

The bone marrow provides a protective environment for acute myeloid leukemia (AML) cells that often allows leukemic stem cells to survive standard chemotherapeutic regimens. Targeting these leukemic stem cells within the bone marrow is critical for preventing relapse. We recently demonstrated that SDF-1, a chemokine abundant in the bone marrow, induces apoptosis in AML cell lines and in patient samples expressing high levels of its receptor, CXCR4. Here we show that a subset of osteoblast lineage cells within the bone marrow can protect AML cells from undergoing apoptosis in response to the SDF-1 naturally present in that location. In co-culture systems, osteoblasts at various stages of differentiation protected AML cell lines and patient isolates from SDF-1-induced apoptosis. The differentiation of the osteoblast cell lines, MC3T3 and W-20-17, mediated this protection via a cell contact-independent mechanism. In contrast, bone marrow-derived mesenchymal cells, the precursors of osteoblasts, induced apoptosis in AML cells via a CXCR4-dependent mechanism and failed to protect AML cells from exogenously added SDF-1. These results indicate that osteoblasts in the process of differentiation potently inhibit the SDF-1-driven apoptotic pathway of CXCR4-expressing AML cells residing in the bone marrow. Drugs targeting this protective mechanism could potentially provide a new approach to treating AML by enhancing the SDF-1-induced apoptosis of AML cells residing within the bone marrow microenvironment. PMID:24851270

Induction of a program gene expression during osteoblast differentiation with strontium ranelate

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Zhu Lingling; Zaidi, Samir; Peng Yuanzhen; Zhou Hang; Moonga, Baljit S.; Blesius, Alexia; Dupin-Roger, Isabelle; Zaidi, Mone; Sun Li

2007-01-01

Strontium ranelate, a new agent for the treatment of osteoporosis, has been shown stimulate bone formation in various experimental models. This study examines the effect of strontium ranelate on gene expression in osteoblasts, as well as the formation of mineralized (von Kossa-positive) colony-forming unit-osteoblasts (CFU-obs). Bone marrow-derived stromal cells cultured for 21 days under differentiating conditions, when exposed to strontium ranelate, displayed a significant time- and concentration-dependent increase in the expression of the master gene, Runx2, as well as bone sialoprotein (BSP), but interestingly without effects on osteocalcin. This was associated with a significant increase in the formation of CFU-obs at day 21 of culture. In U-33 pre-osteoblastic cells, strontium ranelate significantly enhanced the expression of Runx2 and osteocalcin, but not BSP. Late, more mature osteoblastic OB-6 cells showed significant elevations in BSP and osteocalcin, but with only minimal effects on Runx2. In conclusion, strontium ranelate stimulates osteoblast differentiation, but the induction of the program of gene expression appears to be cell type-specific. The increased osteoblastic differentiation is the likely basis underlying the therapeutic bone-forming actions of strontium ranelate

The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells.

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Ahmad Agha, Nezha; Willumeit-Römer, Regine; Laipple, Daniel; Luthringer, Bérengère; Feyerabend, Frank

2016-01-01

Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys) is studied for up to 14 days. Several parameters such as composition of the degradation interface (directly beneath the cells) are analysed with a scanning electron microscope equipped with energy dispersive X-ray and focused ion beam. Furthermore, influence of the materials on cell metabolism is examined via different parameters like active mineralisation process. The results are highlighting the influences of the selected alloying element on the initial cells metabolic activity.

Vitamins D3 and K2 may partially counterbalance the detrimental effects of pentosidine in ex vivo human osteoblasts.

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Sanguineti, R; Monacelli, F; Parodi, A; Furfaro, A L; Borghi, R; Pacini, D; Pronzato, M A; Odetti, P; Molfetta, L; Traverso, N

2016-01-01

Osteoporosis is a metabolic multifaceted disorder, characterized by insufficient bone strength. It has been recently shown that advanced glycation end products (AGEs) play a role in senile osteoporosis, through bone cell impairment and altered biomechanical properties. Pentosidine (PENT), a wellcharacterized AGE, is also considered a biomarker of bone fracture. Adequate responses to various hormones, such as 1,25-dihydroxyvitamin D 3 , are prerequisites for optimal osteoblasts functioning. Vitamin K 2 is known to enhance in vitro and in vitro vitamin D-induced bone formation. The aim of the study was to assess the effects of Vitamins D 3 and K 2 and PENT on in vitro osteoblast activity, to convey a possible translational clinical message. Ex vivo human osteoblasts cultured, for 3 weeks, with vitamin D 3 and vitamin K 2 were exposed to PENT, a well-known advanced glycoxidation end product for the last 72 hours. Experiments with PENT alone were also carried out. Gene expression of specific markers of bone osteoblast maturation [alkaline phosphatase, ALP; collagen I, COL Iα1; and osteocalcin (bone-Gla-protein) BGP] was measured, together with the receptor activator of nuclear factor kappa-B ligand/osteoproteregin (RANKL/OPG) ratio to assess bone remodeling. Expression of RAGE, a well-characterized receptor of AGEs, was also assessed. PENT+vitamins slightly inhibited ALP secretion while not affecting gene expression, indicating hampered osteoblast functional activity. PENT+vitamins up-regulated collagen gene expression, while protein secretion was unchanged. Intracellular collagen levels were partially decreased, and a significant reduction in BGP gene expression and intracellular protein concentration were both reported after PENT exposure. The RANKL/OPG ratio was increased, favouring bone reabsorption. RAGE gene expression significantly decreased. These results were confirmed by a lower mineralization rate. We provided in vitro evidence that glycoxidation might

Reprogramming of Mouse Calvarial Osteoblasts into Induced Pluripotent Stem Cells

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Yinxiang Wang

2018-01-01

Full Text Available Previous studies have demonstrated the ability of reprogramming endochondral bone into induced pluripotent stem (iPS cells, but whether similar phenomenon occurs in intramembranous bone remains to be determined. Here we adopted fluorescence-activated cell sorting-based strategy to isolate homogenous population of intramembranous calvarial osteoblasts from newborn transgenic mice carrying both Osx1-GFP::Cre and Oct4-EGFP transgenes. Following retroviral transduction of Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc, enriched population of osteoblasts underwent silencing of Osx1-GFP::Cre expression at early stage of reprogramming followed by late activation of Oct4-EGFP expression in the resulting iPS cells. These osteoblast-derived iPS cells exhibited gene expression profiles akin to embryonic stem cells and were pluripotent as demonstrated by their ability to form teratomas comprising tissues from all germ layers and also contribute to tail tissue in chimera embryos. These data demonstrate that iPS cells can be generated from intramembranous osteoblasts.

Hypoxia inhibits the growth, differentiation and bone-forming capacity of rat osteoblasts

International Nuclear Information System (INIS)

Utting, J.C.; Robins, S.P.; Brandao-Burch, A.; Orriss, I.R.; Behar, J.; Arnett, T.R.

2006-01-01

We investigated the effect of hypoxia on rat osteoblast function in long-term primary cultures. Reduction of pO 2 from 20% to 5% and 2% decreased formation of mineralized bone nodules 1.7-fold and 11-fold, respectively. When pO 2 was reduced further to 0.2%, bone nodule formation was almost abolished. The inhibitory effect of hypoxia on bone formation was partly due to decreased osteoblast proliferation, as measured by 3 H-thymidine incorporation. Hypoxia also sharply reduced osteoblast alkaline phosphatase (ALP) activity and expression of mRNAs for ALP and osteocalcin, suggesting inhibition of differentiation to the osteogenic phenotype. Hypoxia did not increase the apoptosis of osteoblasts but induced a reversible state of quiescence. Transmission electron microscopy revealed that collagen fibrils deposited by osteoblasts cultured in 2% O 2 were less organized and much less abundant than in 20% O 2 cultures. Furthermore, collagen produced by hypoxic osteoblasts contained a lower percentage of hydroxylysine residues and exhibited an increased sensitivity to pepsin degradation. These data demonstrate the absolute oxygen requirement of osteoblasts for successful bone formation and emphasize the importance of the vasculature in maintaining bone health. We recently showed that hypoxia also acts in a reciprocal manner as a powerful stimulator of osteoclast formation. Considered together, our results help to explain the bone loss that occurs at the sites of fracture, tumors, inflammation and infection, and in individuals with vascular disease or anemia

Quantification of carbon nanotube induced adhesion of osteoblast on hydroxyapatite using nano-scratch technique

International Nuclear Information System (INIS)

Lahiri, Debrupa; Agarwal, Arvind; Benaduce, Ana Paula; Kos, Lidia

2011-01-01

This paper explores the nano-scratch technique for measuring the adhesion strength of a single osteoblast cell on a hydroxyapatite (HA) surface reinforced with carbon nanotubes (CNTs). This technique efficiently separates out the contribution of the environment (culture medium and substrate) from the measured adhesion force of the cell, which is a major limitation of the existing techniques. Nano-scratches were performed on plasma sprayed hydroxyapatite (HA) and HA-CNT coatings to quantify the adhesion of the osteoblast. The presence of CNTs in HA coating promotes an increase in the adhesion of osteoblasts. The adhesion force and energy of an osteoblast on a HA-CNT surface are 17 ± 2 μN/cell and 78 ± 14 pJ/cell respectively, as compared to 11 ± 2 μN/cell and 45 ± 10 pJ/cell on a HA surface after 1 day of incubation. The adhesion force and energy of the osteoblasts increase on both the surfaces with culture periods of up to 5 days. This increase is more pronounced for osteoblasts cultured on HA-CNT. Staining of actin filaments revealed a higher spreading and attachment of osteoblasts on a surface containing CNTs. The affinity of CNTs to conjugate with integrin and other proteins is responsible for the enhanced attachment of osteoblasts. Our results suggest that the addition of CNTs to surfaces used in medical applications may be beneficial when stronger adhesion of osteoblasts is desired.

Estrogen and estrogen receptor alpha promotes malignancy and osteoblastic tumorigenesis in prostate cancer.

Science.gov (United States)

Mishra, Sweta; Tai, Qin; Gu, Xiang; Schmitz, James; Poullard, Ashley; Fajardo, Roberto J; Mahalingam, Devalingam; Chen, Xiaodong; Zhu, Xueqiong; Sun, Lu-Zhe

2015-12-29

The role of estrogen signaling in regulating prostate tumorigenesis is relatively underexplored. Although, an increasing body of evidence has linked estrogen receptor beta (ERß) to prostate cancer, the function of estrogen receptor alpha (ERα) in prostate cancer is not very well studied. We have discovered a novel role of ERα in the pathogenesis of prostate tumors. Here, we show that prostate cancer cells express ERα and estrogen induces oncogenic properties in prostate cancer cells through ERα. Importantly, ERα knockdown in the human prostate cancer PacMetUT1 cells as well as pharmacological inhibition of ERα with ICI 182,780 inhibited osteoblastic lesion formation and lung metastasis in vivo. Co-culture of pre-osteoblasts with cancer cells showed a significant induction of osteogenic markers in the pre-osteoblasts, which was attenuated by knockdown of ERα in cancer cells suggesting that estrogen/ERα signaling promotes crosstalk between cancer and osteoblastic progenitors to stimulate osteoblastic tumorigenesis. These results suggest that ERα expression in prostate cancer cells is essential for osteoblastic lesion formation and lung metastasis. Thus, inhibition of ERα signaling in prostate cancer cells may be a novel therapeutic strategy to inhibit the osteoblastic lesion development as well as lung metastasis in patients with advanced prostate cancer.

Actionable Metabolic Pathways in Heart Failure and Cancer—Lessons From Cancer Cell Metabolism

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Anja Karlstaedt

2018-06-01

Full Text Available Recent advances in cancer cell metabolism provide unprecedented opportunities for a new understanding of heart metabolism and may offer new approaches for the treatment of heart failure. Key questions driving the cancer field to understand how tumor cells reprogram metabolism and to benefit tumorigenesis are also applicable to the heart. Recent experimental and conceptual advances in cancer cell metabolism provide the cardiovascular field with the unique opportunity to target metabolism. This review compares cancer cell metabolism and cardiac metabolism with an emphasis on strategies of cellular adaptation, and how to exploit metabolic changes for therapeutic benefit.

Vitamin a is a negative regulator of osteoblast mineralization.

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Thomas Lind

Full Text Available An excessive intake of vitamin A has been associated with an increased risk of fractures in humans. In animals, a high vitamin A intake leads to a reduction of long bone diameter and spontaneous fractures. Studies in rodents indicate that the bone thinning is due to increased periosteal bone resorption and reduced radial growth. Whether the latter is a consequence of direct effects on bone or indirect effects on appetite and general growth is unknown. In this study we therefore used pair-feeding and dynamic histomorphometry to investigate the direct effect of a high intake of vitamin A on bone formation in rats. Although there were no differences in body weight or femur length compared to controls, there was an approximately halved bone formation and mineral apposition rate at the femur diaphysis of rats fed vitamin A. To try to clarify the mechanism(s behind this reduction, we treated primary human osteoblasts and a murine preosteoblastic cell line (MC3T3-E1 with the active metabolite of vitamin A; retinoic acid (RA, a retinoic acid receptor (RAR antagonist (AGN194310, and a Cyp26 inhibitor (R115866 which blocks endogenous RA catabolism. We found that RA, via RARs, suppressed in vitro mineralization. This was independent of a negative effect on osteoblast proliferation. Alkaline phosphatase and bone gamma carboxyglutamate protein (Bglap, Osteocalcin were drastically reduced in RA treated cells and RA also reduced the protein levels of Runx2 and Osterix, key transcription factors for progression to a mature osteoblast. Normal osteoblast differentiation involved up regulation of Cyp26b1, the major enzyme responsible for RA degradation, suggesting that a drop in RA signaling is required for osteogenesis analogous to what has been found for chondrogenesis. In addition, RA decreased Phex, an osteoblast/osteocyte protein necessary for mineralization. Taken together, our data indicate that vitamin A is a negative regulator of osteoblast mineralization.

A trans-acting enhancer modulates estrogen-mediated transcription of reporter genes in osteoblasts.

Science.gov (United States)

Sasaki-Iwaoka, H; Maruyama, K; Endoh, H; Komori, T; Kato, S; Kawashima, H

1999-02-01

The presence of bone-specific estrogen agonists and discovery of the osteoblast-specific transcription factor (TF), Cbfa1, together with the discovery of synergism between a TF Pit-1 and estrogen receptor alpha (ERalpha) on rat prolactin gene, led to investigation of Cbfa1 in the modulation of osteoblast-specific actions of estrogen. Reverse transcribed-polymerase chain reaction demonstrated expression of Cbfa1 in the osteoblastic cell lines, MG63, ROS17/2.8, and MC3T3E1, but not in nonosteoblastic cell lines, MCF7, C3H10T1/2, and HeLa. An ER expression vector and a series of luciferase (Luc) reporter plasmids harboring the Cbfa1 binding site OSE2 (the osteoblast-specific cis element in the osteocalcin promoter) and palindromic estrogen response elements (EREs) were cotransfected into both osteoblastic and nonosteoblastic cells. OSE2 worked as a cis- acting element in osteoblastic cells but not nonosteoblastic cells, whereas EREs were cis- acting in all cell lines. Synergistic transactivation was observed in osteoblastic cells only when both ERE and OSE2 were placed in juxtaposition to the promoter. Forced expression of Cbfa1 in C3H10T1/2 cells also induced synergism. Tamoxifen, a partial agonist/antagonist of estrogen, acted as an osteoblast-specific agonist in cells transfected with a promoter containing ERE and acted synergistically with a promoter containing the ERE-OSE2 enhancer combination. These results support the idea that bone-specific TFs modulate the actions of estrogen in a tissue-specific manner.

Epigenetic Library Screen Identifies Abexinostat as Novel Regulator of Adipocytic and Osteoblastic Differentiation of Human Skeletal (Mesenchymal) Stem Cells

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Ali, Dalia; Hamam, Rimi; Alfayez, Musaed; Kassem, Moustapha; Aldahmash, Abdullah

2016-01-01

inhibitors, transcription factors, and differentiation pathways controlling adipocyte and osteoblast differentiation of hMSCs. Manipulating such pathways allows a novel use for epigenetic compounds in hMSC-based therapies for tissue engineering, bone disease, obesity, and metabolic-disorders. PMID:27194745

Expression of POEM, a positive regulator of osteoblast differentiation, is suppressed by TNF-α

International Nuclear Information System (INIS)

Tsukasaki, Masayuki; Yamada, Atsushi; Suzuki, Dai; Aizawa, Ryo; Miyazono, Agasa; Miyamoto, Yoichi; Suzawa, Tetsuo; Takami, Masamichi; Yoshimura, Kentaro; Morimura, Naoko; Yamamoto, Matsuo; Kamijo, Ryutaro

2011-01-01

Highlights: → TNF-α inhibits POEM gene expression. → Inhibition of POEM gene expression is caused by NF-κB activation by TNF-α. → Over-expression of POEM recovers inhibition of osteoblast differentiation by TNF-α. -- Abstract: POEM, also known as nephronectin, is an extracellular matrix protein considered to be a positive regulator of osteoblast differentiation. In the present study, we found that tumor necrosis factor-α (TNF-α), a key regulator of bone matrix properties and composition that also inhibits terminal osteoblast differentiation, strongly inhibited POEM expression in the mouse osteoblastic cell line MC3T3-E1. TNF-α-induced down-regulation of POEM gene expression occurred in both time- and dose-dependent manners through the nuclear factor kappa B (NF-κB) pathway. In addition, expressions of marker genes in differentiated osteoblasts were down-regulated by TNF-α in a manner consistent with our findings for POEM, while over-expression of POEM recovered TNF-α-induced inhibition of osteoblast differentiation. These results suggest that TNF-α inhibits POEM expression through the NF-κB signaling pathway and down-regulation of POEM influences the inhibition of osteoblast differentiation by TNF-α.

Expression of POEM, a positive regulator of osteoblast differentiation, is suppressed by TNF-{alpha}

Energy Technology Data Exchange (ETDEWEB)

Tsukasaki, Masayuki [Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Yamada, Atsushi, E-mail: yamadaa@dent.showa-u.ac.jp [Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Suzuki, Dai [Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Aizawa, Ryo [Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Department of Periodontology, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ohta, Tokyo 145-8515 (Japan); Miyazono, Agasa [Department of Periodontology, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ohta, Tokyo 145-8515 (Japan); Miyamoto, Yoichi; Suzawa, Tetsuo; Takami, Masamichi; Yoshimura, Kentaro [Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Morimura, Naoko [Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Yamamoto, Matsuo [Department of Periodontology, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ohta, Tokyo 145-8515 (Japan); Kamijo, Ryutaro [Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan)

2011-07-15

Highlights: {yields} TNF-{alpha} inhibits POEM gene expression. {yields} Inhibition of POEM gene expression is caused by NF-{kappa}B activation by TNF-{alpha}. {yields} Over-expression of POEM recovers inhibition of osteoblast differentiation by TNF-{alpha}. -- Abstract: POEM, also known as nephronectin, is an extracellular matrix protein considered to be a positive regulator of osteoblast differentiation. In the present study, we found that tumor necrosis factor-{alpha} (TNF-{alpha}), a key regulator of bone matrix properties and composition that also inhibits terminal osteoblast differentiation, strongly inhibited POEM expression in the mouse osteoblastic cell line MC3T3-E1. TNF-{alpha}-induced down-regulation of POEM gene expression occurred in both time- and dose-dependent manners through the nuclear factor kappa B (NF-{kappa}B) pathway. In addition, expressions of marker genes in differentiated osteoblasts were down-regulated by TNF-{alpha} in a manner consistent with our findings for POEM, while over-expression of POEM recovered TNF-{alpha}-induced inhibition of osteoblast differentiation. These results suggest that TNF-{alpha} inhibits POEM expression through the NF-{kappa}B signaling pathway and down-regulation of POEM influences the inhibition of osteoblast differentiation by TNF-{alpha}.

Biocompatibility of chitosan-coated iron oxide nanoparticles with osteoblast cells

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Shi S

2012-10-01

Full Text Available Si-Feng Shi,1 Jing-Fu Jia,2 Xiao-Kui Guo,3 Ya-Ping Zhao,2 De-Sheng Chen,1 Yong-Yuan Guo,1 Tao Cheng,1 Xian-Long Zhang11Department of Orthopedic Surgery, Shanghai Sixth People’s Hospital, School of Medicine, 2School of Chemistry and Chemical Technology, 3Department of Medical Microbiology and Parasitology, School of Medicine, Shanghai Jiao Tong University Shanghai, ChinaBackground: Bone disorders (including osteoporosis, loosening of a prosthesis, and bone infections are of great concern to the medical community and are difficult to cure. Therapies are available to treat such diseases, but all have drawbacks and are not specifically targeted to the site of disease. Chitosan is widely used in the biomedical community, including for orthopedic applications. The aim of the present study was to coat chitosan onto iron oxide nanoparticles and to determine its effect on the proliferation and differentiation of osteoblasts.Methods: Nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, x-ray diffraction, zeta potential, and vibrating sample magnetometry. Uptake of nanoparticles by osteoblasts was studied by transmission electron microscopy and Prussian blue staining. Viability and proliferation of osteoblasts were measured in the presence of uncoated iron oxide magnetic nanoparticles or those coated with chitosan. Lactate dehydrogenase, alkaline phosphatase, total protein synthesis, and extracellular calcium deposition was studied in the presence of the nanoparticles.Results: Chitosan-coated iron oxide nanoparticles enhanced osteoblast proliferation, decreased cell membrane damage, and promoted cell differentiation, as indicated by an increase in alkaline phosphatase and extracellular calcium deposition. Chitosan-coated iron oxide nanoparticles showed good compatibility with osteoblasts.Conclusion: Further research is necessary to optimize magnetic nanoparticles for the treatment of bone disease

Notch Inhibits Osteoblast Differentiation and Causes Osteopenia

Science.gov (United States)

Zanotti, Stefano; Smerdel-Ramoya, Anna; Stadmeyer, Lisa; Durant, Deena; Radtke, Freddy; Canalis, Ernesto

2008-01-01

Notch receptors are determinants of cell fate decisions. To define the role of Notch in the adult skeleton, we created transgenic mice overexpressing the Notch intracellular domain (NICD) under the control of the type I collagen promoter. First-generation transgenics were small and osteopenic. Bone histomorphometry revealed that NICD caused a decrease in bone volume, secondary to a reduction in trabecular number; osteoblast and osteoclast number were decreased. Low fertility of founder mice and lethality of young pups did not allow the complete establishment of transgenic lines. To characterize the effect of Notch overexpression in vitro, NICD was induced in osteoblasts and stromal cells from Rosanotch mice, in which a STOP cassette flanked by loxP sites is upstream of NICD, by transduction with an adenoviral vector expressing Cre recombinase (Cre) under the control of the cytomegalovirus (CMV) promoter (Ad-CMV-Cre). NICD impaired osteoblastogenesis and inhibited Wnt/β-catenin signaling. To determine the effects of notch1 deletion in vivo, mice in which notch1 was flanked by loxP sequences (notch1loxP/loxP) were mated with mice expressing Cre recombinase under the control of the osteocalcin promoter. Conditional null notch1 mice had no obvious skeletal phenotype, possibly because of rescue by notch2; however, 1-month-old females exhibited a modest increase in osteoclast surface and eroded surface. Osteoblasts from notch1loxP/loxP mice, transduced with Ad-CMV-Cre and transfected with Notch2 small interfering RNA, displayed increased alkaline phosphatase activity. In conclusion, Notch signaling in osteoblasts causes osteopenia and impairs osteo-blastogenesis by inhibiting the Wnt/β-catenin pathway. PMID:18420737

Vinpocetine Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells.

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Yun-Yun Ma

Full Text Available Vascular calcification is an active process of osteoblastic differentiation of vascular smooth muscle cells; however, its definite mechanism remains unknown. Vinpocetine, a derivative of the alkaloid vincamine, has been demonstrated to inhibit the high glucose-induced proliferation of vascular smooth muscle cells; however, it remains unknown whether vinpocetine can affect the osteoblastic differentiation of vascular smooth muscle cells. We hereby investigated the effect of vinpocetine on vascular calcification using a beta-glycerophosphate-induced cell model. Our results showed that vinpocetine significantly reduced the osteoblast-like phenotypes of vascular smooth muscle cells including ALP activity, osteocalcin, collagen type I, Runx2 and BMP-2 expression as well as the formation of mineralized nodule. Vinpocetine, binding to translocation protein, induced phosphorylation of extracellular signal-related kinase and Akt and thus inhibited the translocation of nuclear factor-kappa B into the nucleus. Silencing of translocator protein significantly attenuated the inhibitory effect of vinpocetine on osteoblastic differentiation of vascular smooth muscle cells. Taken together, vinpocetine may be a promising candidate for the clinical therapy of vascular calcification.

Celecoxib inhibits osteoblast maturation by suppressing the expression of Wnt target genes

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Akihiro Nagano

2017-01-01

Full Text Available Non-steroidal anti-inflammatory drugs (NSAIDs have been shown to impair bone healing. We previously reported that in colon cancer cells, celecoxib, a COX-2-selective NSAID, inhibited the canonical Wnt/β-catenin signaling pathway. Since this pathway also plays an important role in osteoblast growth and differentiation, we examined the effect of celecoxib on maturation of osteoblast-like cell line MC3T3-E1. Celecoxib induced degradation of transcription factor 7-like 2, a key transcription factor of the canonical Wnt pathway. Subsequently, we analyzed the effect of celecoxib on two osteoblast differentiation markers; runt-related transcription factor 2 (RUNX2 and alkaline phosphatase (ALP, both of which are the products of the canonical Wnt pathway target genes. Celecoxib inhibited the expression of both RUNX2 and ALP by suppressing their promoter activity. Consistent with these observations, celecoxib also strongly inhibited osteoblast-mediated mineralization. These results suggest that celecoxib inhibits osteoblast maturation by suppressing Wnt target genes, and this could be the mechanism that NSAIDs inhibit bone formation and fracture healing.

The Degradation Interface of Magnesium Based Alloys in Direct Contact with Human Primary Osteoblast Cells.

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Nezha Ahmad Agha

Full Text Available Magnesium alloys have been identified as a new generation material of orthopaedic implants. In vitro setups mimicking physiological conditions are promising for material / degradation analysis prior to in vivo studies however the direct influence of cell on the degradation mechanism has never been investigated. For the first time, the direct, active, influence of human primary osteoblasts on magnesium-based materials (pure magnesium, Mg-2Ag and Mg-10Gd alloys is studied for up to 14 days. Several parameters such as composition of the degradation interface (directly beneath the cells are analysed with a scanning electron microscope equipped with energy dispersive X-ray and focused ion beam. Furthermore, influence of the materials on cell metabolism is examined via different parameters like active mineralisation process. The results are highlighting the influences of the selected alloying element on the initial cells metabolic activity.

Osteoblast growth behavior on porous-structure titanium surface

Energy Technology Data Exchange (ETDEWEB)

Tian Yuan; Ding Siyang; Peng Hui; Lu Shanming; Wang Guoping [Research Institute of Stomatology, Nanjing Medical University, Nanjing 210029 (China); Xia Lu, E-mail: shelueia@yahoo.com.cn [Research Institute of Stomatology, Nanjing Medical University, Nanjing 210029 (China); Wang Peizhi, E-mail: wangpzi@sina.com [Research Institute of Stomatology, Nanjing Medical University, Nanjing 210029 (China)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Micro-arc oxidation technology formed a porous feature on titanium surface. Black-Right-Pointing-Pointer This porous surface accelerated adhesion, proliferation and differentiation compared with smooth surface. Black-Right-Pointing-Pointer Osteogenesis-related proteins and genes were up regulated by this porous surface. Black-Right-Pointing-Pointer It is anticipated that micro-arc oxidation surface could enhance osteoblastic activity and bone regeneration. - Abstract: A bioavailable surface generated by nano-technology could accelerate implant osteointegration, reduce healing time and enable implants to bear early loading. In this study, a nano-porous surface of titanium wafers was modified using micro-arc oxidation technique; surface of smooth titanium was used as control group. Surface characteristic was evaluated by investigating morphology, roughness and hydrophilicity of titanium wafers. In vitro studies, osteoblastic adhesion, proliferation and ALP activity, as well as gene and protein expressions relative to mineralization were assayed. Our results showed that a crater-liked nano-porous surface with greater roughness and better hydrophilicity were fabricated by micro-arc oxidation. It was further indicated that nano-porous surface could enhance adhesion, proliferation and ALP activity of osteoblasts compared with smooth surfaces. In addition, gene and protein expression of collagen-I, osteocalcin and osteopontin were also obviously increased. In summary, micro-arc oxidized techniques could form an irregular nano-porous morphology on implant surface which is favorable to improve osteoblastic function and prospected to be a potent modification of dental implant.

Osteoblast growth behavior on porous-structure titanium surface

International Nuclear Information System (INIS)

Tian Yuan; Ding Siyang; Peng Hui; Lu Shanming; Wang Guoping; Xia Lu; Wang Peizhi

2012-01-01

Highlights: ► Micro-arc oxidation technology formed a porous feature on titanium surface. ► This porous surface accelerated adhesion, proliferation and differentiation compared with smooth surface. ► Osteogenesis-related proteins and genes were up regulated by this porous surface. ► It is anticipated that micro-arc oxidation surface could enhance osteoblastic activity and bone regeneration. - Abstract: A bioavailable surface generated by nano-technology could accelerate implant osteointegration, reduce healing time and enable implants to bear early loading. In this study, a nano-porous surface of titanium wafers was modified using micro-arc oxidation technique; surface of smooth titanium was used as control group. Surface characteristic was evaluated by investigating morphology, roughness and hydrophilicity of titanium wafers. In vitro studies, osteoblastic adhesion, proliferation and ALP activity, as well as gene and protein expressions relative to mineralization were assayed. Our results showed that a crater-liked nano-porous surface with greater roughness and better hydrophilicity were fabricated by micro-arc oxidation. It was further indicated that nano-porous surface could enhance adhesion, proliferation and ALP activity of osteoblasts compared with smooth surfaces. In addition, gene and protein expression of collagen-I, osteocalcin and osteopontin were also obviously increased. In summary, micro-arc oxidized techniques could form an irregular nano-porous morphology on implant surface which is favorable to improve osteoblastic function and prospected to be a potent modification of dental implant.

Nanostructured magnesium has fewer detrimental effects on osteoblast function

Science.gov (United States)

Weng, Lucy; Webster, Thomas J

2013-01-01

Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells). Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications. PMID:23674891

Nanostructured magnesium has fewer detrimental effects on osteoblast function.

Science.gov (United States)

Weng, Lucy; Webster, Thomas J

2013-01-01

Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells). Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications.

Osteogenic differentiation of immature osteoblasts: Interplay of cell culture media and supplements.

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Brauer, A; Pohlemann, T; Metzger, W

2016-01-01

Differentiation of immature osteoblasts to mature osteoblasts in vitro initially was induced by supplementing the medium with β-gylcerophosphate and dexamethasone. Later, ascorbic acid, vitamin D3, vitamin K3 and TGFβ1 were used in varying concentrations as supplements to generate a mature osteoblast phenotype. We tested the effects of several combinations of cell culture media, seeding protocols and osteogenic supplements on osteogenic differentiation of human primary osteoblasts. Osteogenic differentiation was analyzed by staining alkaline phosphatase (ALP) with 5-bromo-4-chloro-3-indolyl-phosphate/nitro blue tetrazolium (BCIP/NBT) and by von Kossa staining of deposited calcium phosphate. The combinations of culture media and supplements significantly influenced osteogenic differentiation, but the seeding protocol did not. Staining of ALP and calcium phosphate could be achieved only if our own mix of osteogenic supplements was used in combination with Dulbecco's modified Eagle medium or if a commercial mix of osteogenic supplements was used in combination with osteoblast growth medium. Especially for von Kossa, we observed great variations in the staining intensity. Because osteogenic differentiation is a complex process, the origin of the osteoblasts, cell culture media and osteogenic supplements should be established by preliminary experiments to achieve optimal differentiation. Staining of ALP or deposited calcium phosphate should be supplemented with qRT-PCR studies to learn more about the influence of specific supplements on osteogenic markers.

The flavonoid fisetin promotes osteoblasts differentiation through Runx2 transcriptional activity.

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Léotoing, Laurent; Davicco, Marie-Jeanne; Lebecque, Patrice; Wittrant, Yohann; Coxam, Véronique

2014-06-01

Flavonoids represent a group of polyphenolic compounds commonly found in daily nutrition with proven health benefits. Among this group, the flavonol fisetin has been previously shown to protect bone by repressing osteoclast differentiation. In the present study, we investigated the role of fisetin in regulating osteoblasts physiology. In vivo mice treated with LPSs exhibited osteoporosis features associated with a dramatic repression of osteoblast marker expression. In this model, inhibition of osteocalcin and type I collagen alpha 1 transcription was partially countered by a daily consumption of fisetin. Interestingly, in vitro, fisetin promoted both osteoblast alkaline phosphatase activity and mineralization process. To decipher how fisetin may exert its positive effect on osteoblastogenesis, we analyzed its ability to control the runt-related transcription factor 2 (Runx2), a key organizer in developing and maturing osteoblasts. While fisetin did not impact Runx2 mRNA and protein levels, it upregulated its transcriptional activity. Actually, fisetin stimulated the luciferase activity of a reporter plasmid driven by the osteocalcin gene promoter that contains Runx2 binding sites and promoted the mRNA expression of osteocalcin and type I collagen alpha 1 targets. Bone sparing properties of fisetin also rely on its positive influence on osteoblast differentiation and activity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanotransductive Regulation of Gap-Junction Activity Between MLO-Y4 Osteocyte-Like and MC3T3-E1 Osteoblast-Like Cells in Three-Dimensional Co-Culture.

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Juran, C. M.; Blaber, E. A.; Almeida, E. A. C.

2016-01-01

Cell and animal studies conducted onboard the International Space Station and formerly on Shuttle flights have provided groundbreaking data illuminating the deleterious biological response of bone to mechanical unloading. However the intercellular communicative mechanisms associated with the regulation of bone synthesis and bone resorption cells are still largely unknown. Connexin-43 (CX43), a gap junction protein, is hypothesized to play a significant role in osteoblast and osteocyte signaling. The purpose of this investigation was to evaluate within a novel three-dimensional microenvironment how the osteocyte-osteoblast gap-junction expression changes when cultures are exposed to exaggerated mechanical load. MLO-Y4 osteocyte-like cells were cultured on a 3D-Biotek polystyrene insert and placed in direct contact with an MC3T3-E1 pre-osteoblast co-cultured monolayer and exposed to 48 h of mechanical stimulation (pulsatile fluid flow (PFF) or monolayer cyclic stretch (MCS)) then evaluated for viability, proliferation, metabolism, and CX43 expression. Mono-cultured MLO-Y4 and MC3T3-E1 control experiments were conducted under PFF and MCS stimulation to observe how strain application stimuli (PFF cell membrane shear or MCS cell focal adhesion/attachment loading) initiates different signaling pathways or downstream regulatory controls. TotalLive cell count, viability and metabolic reduction (Trypan Blue, LIVEDead and Alamar Blue analysis respectively) indicate that mechanical activation of MC3T3-E1 cells inhibits proliferation while maintaining an average 1.04E4 reductioncell metabolic rate, *p0.05 n4. MLO-Y4s in monolayer culture increase in number when exposed to MCS loading but the percent of live cells within the population is low (46.3 total count, *p0.05 n4), these results may indicate an apoptotic signaling cascade. PFF stimulation of the three-dimensional co-cultures elicits a universal increase in CX43 in MLO-Y4 and MC3T3-E1 cells, illustrated by

Mechanical unloading reduces microtubule actin crosslinking factor 1 expression to inhibit β-catenin signaling and osteoblast proliferation.

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Yin, Chong; Zhang, Yan; Hu, Lifang; Tian, Ye; Chen, Zhihao; Li, Dijie; Zhao, Fan; Su, Peihong; Ma, Xiaoli; Zhang, Ge; Miao, Zhiping; Wang, Liping; Qian, Airong; Xian, Cory J

2018-07-01

Mechanical unloading was considered a major threat to bone homeostasis, and has been shown to decrease osteoblast proliferation although the underlying mechanism is unclear. Microtubule actin crosslinking factor 1 (MACF1) is a cytoskeletal protein that regulates cellular processes and Wnt/β-catenin pathway, an essential signaling pathway for osteoblasts. However, the relationship between MACF1 expression and mechanical unloading, and the function and the associated mechanisms of MACF1 in regulating osteoblast proliferation are unclear. This study investigated effects of mechanical unloading on MACF1 expression levels in cultured MC3T3-E1 osteoblastic cells and in femurs of mice with hind limb unloading; and it also examined the role and potential action mechanisms of MACF1 in osteoblast proliferation in MACF1-knockdown, overexpressed or control MC3T3-E1 cells treated with or without the mechanical unloading condition. Results showed that the mechanical unloading condition inhibited osteoblast proliferation and MACF1 expression in MC3T3-E1 osteoblastic cells and mouse femurs. MACF1 knockdown decreased osteoblast proliferation, while MACF1 overexpression increased it. The inhibitory effect of mechanical unloading on osteoblast proliferation also changed with MACF1 expression levels. Furthermore, MACF1 was found to enhance β-catenin expression and activity, and mechanical unloading decreased β-catenin expression through MACF1. Moreover, β-catenin was found an important regulator of osteoblast proliferation, as its preservation by treatment with its agonist lithium attenuated the inhibitory effects of MACF1-knockdown or mechanical unloading on osteoblast proliferation. Taken together, mechanical unloading decreases MACF1 expression, and MACF1 up-regulates osteoblast proliferation through enhancing β-catenin signaling. This study has thus provided a mechanism for mechanical unloading-induced inhibited osteoblast proliferation. © 2017 Wiley Periodicals, Inc.

Repression of osteoblast maturation by ERRα accounts for bone loss induced by estrogen deficiency.

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Marlène Gallet

Full Text Available ERRα is an orphan member of the nuclear receptor family, the complete inactivation of which confers resistance to bone loss induced by ageing and estrogen withdrawal to female mice in correlation with increased bone formation in vivo. Furthermore ERRα negatively regulates the commitment of mesenchymal cells to the osteoblast lineage ex vivo as well as later steps of osteoblast maturation. We searched to determine whether the activities of ERRα on osteoblast maturation are responsible for one or both types of in vivo induced bone loss. To this end we have generated conditional knock out mice in which the receptor is normally present during early osteoblast differentiation but inactivated upon osteoblast maturation. Bone ageing in these animals was similar to that observed for control animals. In contrast conditional ERRαKO mice were completely resistant to bone loss induced by ovariectomy. We conclude that the late (maturation, but not early (commitment, negative effects of ERRα on the osteoblast lineage contribute to the reduced bone mineral density observed upon estrogen deficiency.

Repression of osteoblast maturation by ERRα accounts for bone loss induced by estrogen deficiency.

Science.gov (United States)

Gallet, Marlène; Saïdi, Soraya; Haÿ, Eric; Photsavang, Johann; Marty, Caroline; Sailland, Juliette; Carnesecchi, Julie; Tribollet, Violaine; Barenton, Bruno; Forcet, Christelle; Birling, Marie-Christine; Sorg, Tania; Chassande, Olivier; Cohen-Solal, Martine; Vanacker, Jean-Marc

2013-01-01

ERRα is an orphan member of the nuclear receptor family, the complete inactivation of which confers resistance to bone loss induced by ageing and estrogen withdrawal to female mice in correlation with increased bone formation in vivo. Furthermore ERRα negatively regulates the commitment of mesenchymal cells to the osteoblast lineage ex vivo as well as later steps of osteoblast maturation. We searched to determine whether the activities of ERRα on osteoblast maturation are responsible for one or both types of in vivo induced bone loss. To this end we have generated conditional knock out mice in which the receptor is normally present during early osteoblast differentiation but inactivated upon osteoblast maturation. Bone ageing in these animals was similar to that observed for control animals. In contrast conditional ERRαKO mice were completely resistant to bone loss induced by ovariectomy. We conclude that the late (maturation), but not early (commitment), negative effects of ERRα on the osteoblast lineage contribute to the reduced bone mineral density observed upon estrogen deficiency.

Morphology and Differentiation of MG63 Osteoblast Cells on Saliva Contaminated Implant Surfaces

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Neda Shams

2015-11-01

Full Text Available Objectives: Osteoblasts are the most important cells in the osseointegration process. Despite years of study on dental Implants, limited studies have discussed the effect of saliva on the adhesion process of osteoblasts to implant surfaces. The aim of this in vitro study was to evaluate the effect of saliva on morphology and differentiation of osteoblasts attached to implant surfaces.Materials and Methods: Twelve Axiom dental implants were divided into two groups. Implants of the case group were placed in containers, containing saliva, for 40 minutes. Then, all the implants were separately stored in a medium containing MG63 human osteoblasts for a week. Cell morphology and differentiation were assessed using a scanning electron microscope and their alkaline phosphatase (ALP activity was determined. The t-test was used to compare the two groups.Results: Scanning electron microscopic observation of osteoblasts revealed round or square cells with fewer and shorter cellular processes in saliva contaminated samples, whereas elongated, fusiform and well-defined cell processes were seen in the control group. ALP level was significantly lower in case compared to control group (P<0.05.Conclusion: Saliva contamination alters osteoblast morphology and differentiation and may subsequently interfere with successful osseointegration. Thus, saliva contamination of bone and implant must be prevented or minimized.

Cytotoxicity of Titanate-Calcium Complexes to MC3T3 Osteoblast-Like Cells

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Drury, Jeanie L.; Moussi, Joelle; Taylor-Pashow, Kathryn M. L.

2016-01-01

Monosodium titanates (MST) are a relatively novel form of particulate titanium dioxide that have been proposed for biological use as metal sorbents or delivery agents, most recently calcium (II). In these roles, the toxicity of the titanate or its metal complex is crucial to its biological utility. The aim of this study was to determine the cytotoxicity of MST and MST-calcium complexes with MC3T3 osteoblast-like cells; MST-Ca(II) complexes could be useful to promote bone formation in various hard tissue applications. MC3T3 cells were exposed to native MST or MST-Ca(II) complexes for 24–72 h. A CellTiter-Blue® assay was employed to assess the metabolic activity of the cells. The results showed that MST and MST-Ca(II) suppressed MC3T3 metabolic activity significantly in a dose-, time-, and cell-density-dependent fashion. MST-Ca(II) suppressed MC3T3 metabolism in a statistically identical manner as native MST at all concentrations. We concluded that MST and MST-Ca(II) are significantly cytotoxic to MC3T3 cells through a mechanism yet unknown; this is a potential problem to the biological utility of these complexes. PMID:28044136

Cytotoxicity of Titanate-Calcium Complexes to MC3T3 Osteoblast-Like Cells

Directory of Open Access Journals (Sweden)

Yen-Wei Chen

2016-01-01

Full Text Available Monosodium titanates (MST are a relatively novel form of particulate titanium dioxide that have been proposed for biological use as metal sorbents or delivery agents, most recently calcium (II. In these roles, the toxicity of the titanate or its metal complex is crucial to its biological utility. The aim of this study was to determine the cytotoxicity of MST and MST-calcium complexes with MC3T3 osteoblast-like cells; MST-Ca(II complexes could be useful to promote bone formation in various hard tissue applications. MC3T3 cells were exposed to native MST or MST-Ca(II complexes for 24–72 h. A CellTiter-Blue® assay was employed to assess the metabolic activity of the cells. The results showed that MST and MST-Ca(II suppressed MC3T3 metabolic activity significantly in a dose-, time-, and cell-density-dependent fashion. MST-Ca(II suppressed MC3T3 metabolism in a statistically identical manner as native MST at all concentrations. We concluded that MST and MST-Ca(II are significantly cytotoxic to MC3T3 cells through a mechanism yet unknown; this is a potential problem to the biological utility of these complexes.

Identification of Rorβ targets in cultured osteoblasts and in human bone

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Roforth, Matthew M., E-mail: roforth.matthew@mayo.edu; Khosla, Sundeep, E-mail: khosla.sundeep@mayo.edu; Monroe, David G., E-mail: monroe.david@mayo.edu

2013-11-01

Highlights: •We examine the gene expression patterns controlled by Rorβ in osteoblasts. •Genes involved in extracellular matrix regulation and proliferation are affected. •Rorβ mRNA levels increase in aged, human bone biopsies. •Rorβ may affect osteoblast activity by modulation of these pathways. -- Abstract: Control of osteoblastic bone formation involves the cumulative action of numerous transcription factors, including both activating and repressive functions that are important during specific stages of differentiation. The nuclear receptor retinoic acid receptor-related orphan receptor β (Rorβ) has been recently shown to suppress the osteogenic phenotype in cultured osteoblasts, and is highly upregulated in bone marrow-derived osteogenic precursors isolated from aged osteoporotic mice, suggesting Rorβ is an important regulator of osteoblast function. However the specific gene expression patterns elicited by Rorβ are unknown. Using microarray analysis, we identified 281 genes regulated by Rorβ in an MC3T3-E1 mouse osteoblast cell model (MC3T3-Rorβ-GFP). Pathway analysis revealed alterations in genes involved in MAPK signaling, genes involved in extracellular matrix (ECM) regulation, and cytokine-receptor interactions. Whereas the identified Rorβ-regulated ECM genes normally decline during osteoblastic differentiation, they were highly upregulated in this non-mineralizing MC3T3-Rorβ-GFP model system, suggesting that Rorβ may exert its anti-osteogenic effects through ECM disruption. Consistent with these in vitro findings, the expression of both RORβ and a subset of RORβ-regulated genes were increased in bone biopsies from postmenopausal women (73 ± 7 years old) compared to premenopausal women (30 ± 5 years old), suggesting a role for RORβ in human age-related bone loss. Collectively, these data demonstrate that Rorβ regulates known osteogenic pathways, and may represent a novel therapeutic target for age-associated bone loss.

The Sox2 high mobility group transcription factor inhibits mature osteoblast function in transgenic mice

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Holmes, Greg; Bromage, Timothy G.; Basilico, Claudio

2011-01-01

We have previously shown that in osteoblasts Sox2 expression can be induced by Fgfs, and can inhibit Wnt signaling and differentiation. Furthermore, in mice in which Sox2 is conditionally deleted in the osteoblastic lineage, bones are osteopenic, and Sox2 inactivation in cultured osteoblasts leads to a loss of proliferative ability with a senescent phenotype. To help understand the role of Sox2 in osteoblast development we have specifically expressed Sox2 in bone from a Col1α1 promoter, which extended Sox2 expression into more mature osteoblasts. In long bones, trabecular cartilage remodeling was delayed and the transition from endochondral to cortical bone was disrupted, resulting in porous and undermineralized cortical bone. Collagen deposition was disorganized, and patterns of osteoclast activity were altered. Calvarial bones were thinner and parietal bones failed to develop the diploic space. Microarray analysis showed significant up- or downregulation of a variety of genes coding for non-collagenous extracellular matrix proteins, with a number of genes typical of mature osteoblasts being downregulated. Our results position Sox2 as a negative regulator of osteoblast maturation in vivo. PMID:21703370

Effect of nanocoating with rhamnogalacturonan-I on surface properties and osteoblasts response

DEFF Research Database (Denmark)

Gurzawska, Katarzyna Aleksandra; Svava, Rikke; Syberg, Susanne

2012-01-01

-I) on surface properties and osteoblasts response. Three different RG-Is from apple and lupin pectins were modified and coated on amino-functionalized tissue culture polystyrene plates (aminated TCPS). Surface properties were evaluated by scanning electron microscopy, contact angle measurement, atomic force...... microscopy, and X-ray photoelectron spectroscopy. The effects of nanocoating on proliferation, matrix formation and mineralization, and expression of genes (real-time PCR) related to osteoblast differentiation and activity were tested using human osteoblast-like SaOS-2 cells. It was shown that RG-I coatings...

Interaction of Protein Phosphatase 1δ with Nucleophosmin in Human Osteoblastic Cells

International Nuclear Information System (INIS)

Haneji, Tatsuji; Teramachi, Jumpei; Hirashima, Kanji; Kimura, Koji; Morimoto, Hiroyuki

2012-01-01

Protein phosphorylation and dephosphorylation has been recognized as an essential mechanism in the regulation of cellular metabolism and function in various tissues. Serine and threonine protein phosphatases (PP) are divided into four categories: PP1, PP2A, PP2B, and PP2C. At least four isoforms of PP1 catalytic subunit in rat, PP1α, PP1γ1, PP1γ2, and PP1δ, were isolated. In the present study, we examined the localization and expression of PP1δ in human osteoblastic Saos-2 cells. Anti-PP1δ antibody recognized a protein present in the nucleolar regions in Saos-2 cells. Cellular fractionation revealed that PP1δ is a 37 kDa protein localized in the nucleolus. Nucleophosmin is a nucleolar phosphoprotein and located mainly in the nucleolus. Staining pattern of nucleophosmin in Saos-2 cells was similar to that of PP1δ. PP1δ and nucleophosmin were specifically stained as dots in the nucleus. Dual fluorescence images revealed that PP1δ and nucleophosmin were localized in the same regions in the nucleolus. Similar distribution patterns of PP1δ and nucleophosmin were observed in osteoblastic MG63 cells. The interaction of PP1δ and nucleophosmin was also shown by immunoprecipitation and Western analysis. These results indicated that PP1δ associate with nucleophosmin directly in the nucleolus and suggested that nucleophosmin is one of the candidate substrate for PP1δ

Ihh/Gli2 signaling promotes osteoblast differentiation by regulating Runx2 expression and function.

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Shimoyama, Atsuko; Wada, Masahiro; Ikeda, Fumiyo; Hata, Kenji; Matsubara, Takuma; Nifuji, Akira; Noda, Masaki; Amano, Katsuhiko; Yamaguchi, Akira; Nishimura, Riko; Yoneda, Toshiyuki

2007-07-01

Genetic and cell biological studies have indicated that Indian hedgehog (Ihh) plays an important role in bone development and osteoblast differentiation. However, the molecular mechanism by which Ihh regulates osteoblast differentiation is complex and remains to be fully elucidated. In this study, we investigated the role of Ihh signaling in osteoblast differentiation using mesenchymal cells and primary osteoblasts. We observed that Ihh stimulated alkaline phosphatase (ALP) activity, osteocalcin expression, and calcification. Overexpression of Gli2- but not Gli3-induced ALP, osteocalcin expression, and calcification of these cells. In contrast, dominant-negative Gli2 markedly inhibited Ihh-dependent osteoblast differentiation. Ihh treatment or Gli2 overexpression also up-regulated the expression of Runx2, an essential transcription factor for osteoblastogenesis, and enhanced the transcriptional activity and osteogenic action of Runx2. Coimmunoprecipitation analysis demonstrated a physical interaction between Gli2 and Runx2. Moreover, Ihh or Gli2 overexpression failed to increase ALP activity in Runx2-deficient mesenchymal cells. Collectively, these results suggest that Ihh regulates osteoblast differentiation of mesenchymal cells through up-regulation of the expression and function of Runx2 by Gli2.

Direct effects of casein phosphopeptides on growth and differentiation of in vitro cultured osteoblastic cells (MC3T3-E1).

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Tulipano, Giovanni; Bulgari, Omar; Chessa, Stefania; Nardone, Alessandro; Cocchi, Daniela; Caroli, Anna

2010-02-25

Casein phosphopeptides (CPPs) obtained by enzymatic hydrolysis in vitro of caseins, have been shown to enhance calcium solubility and to increase the calcification of embryonic rat bones in their diaphyseal area. Little is known about the direct effects of CPPs on cultured osteoblastic cells. Calcium in the microenvironment surrounding bone cells is not only important for the mineralization of the extracellular matrix, but it is believed to provide preosteblasts with a signal that modulates their proliferation and differentiation. The aim of the present study was to investigate the direct effects of four selected casein phosphopeptides on osteoblastic cell (MC3T3-E1 cells) viability and differentiation. The selected peptides have been obtained by chemical synthesis and differed in the number of phosphorylated sites and in the amino acid spacing out two phosphorylated sites, in order to further characterize the relationship between structure and function. The results obtained in this work demonstrated that CPPs may directly affect osteoblast-like cell growth, calcium uptake and ultimately calcium deposition in the extracellular matrix. The effects exerted by distinct CPPs on osteogenesis in vitro can be either stimulatory or inhibitory. Differential short amino acid sequences in their molecules, like the -SpEE- and the -SpTSpEE-motifs, are likely the molecular determinants for their biological activities on osteoblastic cells. Moreover, two genetic variants of CPPs showing one amino acid change in their sequence may profoundly differ in their biological activities. Finally, our data may also suggest important clues about the role of intrinsic phosphorylated peptides derived from endogenous phosphorylated proteins in bone metabolism, apart from extrinsic CPPs. Copyright 2009 Elsevier B.V. All rights reserved.

Inhibition of osteoclastogenesis by osteoblast-like cells genetically engineered to produce interleukin-10.

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Fujioka, Kazuki; Kishida, Tsunao; Ejima, Akika; Yamamoto, Kenta; Fujii, Wataru; Murakami, Ken; Seno, Takahiro; Yamamoto, Aihiro; Kohno, Masataka; Oda, Ryo; Yamamoto, Toshiro; Fujiwara, Hiroyoshi; Kawahito, Yutaka; Mazda, Osam

2015-01-16

Bone destruction at inflamed joints is an important complication associated with rheumatoid arthritis (RA). Interleukin-10 (IL-10) may suppress not only inflammation but also induction of osteoclasts that play key roles in the bone destruction. If IL-10-producing osteoblast-like cells are induced from patient somatic cells and transplanted back into the destructive bone lesion, such therapy may promote bone remodeling by the cooperative effects of IL-10 and osteoblasts. We transduced mouse fibroblasts with genes for IL-10 and Runx2 that is a crucial transcription factor for osteoblast differentiation. The IL-10-producing induced osteoblast-like cells (IL-10-iOBs) strongly expressed osteoblast-specific genes and massively produced bone matrix that were mineralized by calcium phosphate in vitro and in vivo. Culture supernatant of IL-10-iOBs significantly suppressed induction of osteoclast from RANKL-stimulated Raw264.7 cells as well as LPS-induced production of inflammatory cytokine by macrophages. The IL-10-iOBs may be applicable to novel cell-based therapy against bone destruction associated with RA. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of silica and calcium levels in nanobioglass ceramic particles on osteoblast proliferation

International Nuclear Information System (INIS)

Moorthi, A.; Parihar, P.R.; Saravanan, S.; Vairamani, M.; Selvamurugan, N.

2014-01-01

At nanoscale, bioglass ceramic (nBGC) particles containing calcium oxide (lime), silica and phosphorus pentoxide promote osteoblast proliferation. However, the role of varied amounts of calcium and silica present in nBGC particles on osteoblast proliferation is not yet completely known. Hence, the current work was aimed at synthesizing two different nBGC particles with varied amounts of calcium oxide and silica, nBGC-1: SiO 2 :CaO:P 2 O 5 ; mol% ∼ 70:25:5 and nBGC-2: SiO 2 :CaO:P 2 O 5 ; mol% ∼ 64:31:5, and investigating their role on osteoblast proliferation. The synthesized nBGC particles were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies. They exhibited their size at nanoscale and were non-toxic to human osteoblastic cells (MG-63). The nBGC-2 particles were found to have more effect on stimulation of osteoblast proliferation and promoted entering of more cells into G2/M cell cycle phase compared to nBGC-1 particles. There was a differential expression of cyclin proteins in MG-63 cells by nBGC-1 and nBGC-2 treatments, and the expression of cyclin B1 and E proteins was found to be more by nBGC-2 treatment. Thus, these results provide us a new insight in understanding the design of various nBGC particles by altering their ionic constituents with desirable biological properties thereby supporting bone augmentation. - Highlights: • nBGC particles with varied amounts of calcium and silica were synthesized. • They were non-toxic to human osteoblastic cells. • nBGC-2 particles had more effect on stimulation of osteoblast proliferation. • nBGC-2 particles promoted entering of osteoblasts into G2/M cell cycle phase. • Expression of cyclin B1 and E proteins was found to be more by nBGC-2 treatment

Effects of silica and calcium levels in nanobioglass ceramic particles on osteoblast proliferation

Energy Technology Data Exchange (ETDEWEB)

Moorthi, A.; Parihar, P.R.; Saravanan, S.; Vairamani, M.; Selvamurugan, N., E-mail: selvamurugan.n@ktr.srmuniv.ac.in

2014-10-01

At nanoscale, bioglass ceramic (nBGC) particles containing calcium oxide (lime), silica and phosphorus pentoxide promote osteoblast proliferation. However, the role of varied amounts of calcium and silica present in nBGC particles on osteoblast proliferation is not yet completely known. Hence, the current work was aimed at synthesizing two different nBGC particles with varied amounts of calcium oxide and silica, nBGC-1: SiO{sub 2}:CaO:P{sub 2}O{sub 5}; mol% ∼ 70:25:5 and nBGC-2: SiO{sub 2}:CaO:P{sub 2}O{sub 5}; mol% ∼ 64:31:5, and investigating their role on osteoblast proliferation. The synthesized nBGC particles were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies. They exhibited their size at nanoscale and were non-toxic to human osteoblastic cells (MG-63). The nBGC-2 particles were found to have more effect on stimulation of osteoblast proliferation and promoted entering of more cells into G2/M cell cycle phase compared to nBGC-1 particles. There was a differential expression of cyclin proteins in MG-63 cells by nBGC-1 and nBGC-2 treatments, and the expression of cyclin B1 and E proteins was found to be more by nBGC-2 treatment. Thus, these results provide us a new insight in understanding the design of various nBGC particles by altering their ionic constituents with desirable biological properties thereby supporting bone augmentation. - Highlights: • nBGC particles with varied amounts of calcium and silica were synthesized. • They were non-toxic to human osteoblastic cells. • nBGC-2 particles had more effect on stimulation of osteoblast proliferation. • nBGC-2 particles promoted entering of osteoblasts into G2/M cell cycle phase. • Expression of cyclin B1 and E proteins was found to be more by nBGC-2 treatment.

Collagen films with stabilized liquid crystalline phases and concerns on osteoblast behaviors

Energy Technology Data Exchange (ETDEWEB)

Tang, Minjian; Ding, Shan; Min, Xiang; Jiao, Yanpeng, E-mail: tjiaoyp@jnu.edu.cn; Li, Lihua; Li, Hong; Zhou, Changren, E-mail: tcrz9@jnu.edu.cn

2016-01-01

To duplicate collagen's in vivo liquid crystalline (LC) phase and investigate the relationship between the morphology of LC collagen and osteoblast behavior, a self-assembly method was introduced for preparing collagen films with a stabilized LC phase. The LC texture and topological structure of the films before and after stabilization were observed with polarizing optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The relationship between the collagen films and osteoblast behavior was studied with the 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide method, proliferation index detection, alkaline phosphatase measurements, osteocalcin assay, inverted microscopy, SEM observation, AFM observation, and cytoskeleton fluorescence staining. The results showed that the LC collagen film had continuously twisting orientations in the cholesteric phase with a typical series of arced patterns. The collagen fibers assembled in a well-organized orientation in the LC film. Compared to the non-LC film, the LC collagen film can promote cell proliferation, and increase ALP and osteocalcin expression, revealing a contact guide effect on osteoblasts. - Highlights: • Collagen film with liquid crystalline (LC) phase was observed by POM, SEM and AFM. • The effect of LC collagen film on osteoblasts behaviors was studied in detail. • LC collagen film promoted osteoblast proliferation and osteogenesis activity.

Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 is Expressed inOsteoblasts and Regulated by PTH

International Nuclear Information System (INIS)

Sharma, Sonali; Mahalingam, Chandrika D.; Das, Varsha; Jamal, Shazia; Levi, Edi; Rishi, Arun K.; Datta, Nabanita S.

2013-01-01

Highlights: •CARP-1 is identified for the first time in bone cells. •PTH downregulates CARP-1 expression in differentiated osteoblasts. •PTH displaces CARP-1 from nucleus to the cytoplasm in differentiated osteoblasts. •Downregulation of CARP-1 by PTH involves PKA, PKC and P-p38 MAPK pathways. -- Abstract: Bone mass is dependent on osteoblast proliferation, differentiation and life-span of osteoblasts. Parathyroid hormone (PTH) controls osteoblast cell cycle regulatory proteins and suppresses mature osteoblasts apoptosis. Intermittent administration of PTH increases bone mass but the mechanism of action are complex and incompletely understood. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 (aka CCAR1) is a novel transducer of signaling by diverse agents including cell growth and differentiation factors. To gain further insight into the molecular mechanism, we investigated involvement of CARP-1 in PTH signaling in osteoblasts. Immunostaining studies revealed presence of CARP-1 in osteoblasts and osteocytes, while a minimal to absent levels were noted in the chondrocytes of femora from 10 to 12-week old mice. Treatment of 7-day differentiated MC3T3-E1 clone-4 (MC-4) mouse osteoblastic cells and primary calvarial osteoblasts with PTH for 30 min to 5 h followed by Western blot analysis showed 2- to 3-fold down-regulation of CARP-1 protein expression in a dose- and time-dependent manner compared to the respective vehicle treated control cells. H-89, a Protein Kinase A (PKA) inhibitor, suppressed PTH action on CARP-1 protein expression indicating PKA-dependent mechanism. PMA, a Protein Kinase C (PKC) agonist, mimicked PTH action, and the PKC inhibitor, GF109203X, partially blocked PTH-dependent downregulation of CARP-1, implying involvement of PKC. U0126, a Mitogen-Activated Protein Kinase (MAPK) Kinase (MEK) inhibitor, failed to interfere with CARP-1 suppression by PTH. In contrast, SB203580, p38 inhibitor, attenuated PTH down-regulation of CARP-1

Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 is Expressed inOsteoblasts and Regulated by PTH

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Sharma, Sonali; Mahalingam, Chandrika D.; Das, Varsha [Department of Internal Medicine/Endocrinology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Jamal, Shazia [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Levi, Edi [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Rishi, Arun K. [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States); VA Medical Center, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Datta, Nabanita S., E-mail: ndatta@med.wayne.edu [Department of Internal Medicine/Endocrinology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States)

2013-07-12

Highlights: •CARP-1 is identified for the first time in bone cells. •PTH downregulates CARP-1 expression in differentiated osteoblasts. •PTH displaces CARP-1 from nucleus to the cytoplasm in differentiated osteoblasts. •Downregulation of CARP-1 by PTH involves PKA, PKC and P-p38 MAPK pathways. -- Abstract: Bone mass is dependent on osteoblast proliferation, differentiation and life-span of osteoblasts. Parathyroid hormone (PTH) controls osteoblast cell cycle regulatory proteins and suppresses mature osteoblasts apoptosis. Intermittent administration of PTH increases bone mass but the mechanism of action are complex and incompletely understood. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 (aka CCAR1) is a novel transducer of signaling by diverse agents including cell growth and differentiation factors. To gain further insight into the molecular mechanism, we investigated involvement of CARP-1 in PTH signaling in osteoblasts. Immunostaining studies revealed presence of CARP-1 in osteoblasts and osteocytes, while a minimal to absent levels were noted in the chondrocytes of femora from 10 to 12-week old mice. Treatment of 7-day differentiated MC3T3-E1 clone-4 (MC-4) mouse osteoblastic cells and primary calvarial osteoblasts with PTH for 30 min to 5 h followed by Western blot analysis showed 2- to 3-fold down-regulation of CARP-1 protein expression in a dose- and time-dependent manner compared to the respective vehicle treated control cells. H-89, a Protein Kinase A (PKA) inhibitor, suppressed PTH action on CARP-1 protein expression indicating PKA-dependent mechanism. PMA, a Protein Kinase C (PKC) agonist, mimicked PTH action, and the PKC inhibitor, GF109203X, partially blocked PTH-dependent downregulation of CARP-1, implying involvement of PKC. U0126, a Mitogen-Activated Protein Kinase (MAPK) Kinase (MEK) inhibitor, failed to interfere with CARP-1 suppression by PTH. In contrast, SB203580, p38 inhibitor, attenuated PTH down-regulation of CARP-1

Treatment with 1,25-dihydroxyvitamin D3 reduces impairment of human osteoblast functions during cellular aging in culture

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Kveiborg, M.; Rattan, Suresh; Eriksen, E.F.

2001-01-01

is due to impaired responsiveness to calcitriol known to be important for the regulation of biological activities of the osteoblasts. Thus, we examined changes in vitamin D receptor (VDR) system and the osteoblastic responses to calcitriol treatment during in vitro osteoblast aging. We found no change...... in the amount of VDR at either steady state mRNA level or protein level with increasing in vitro osteoblast age and examination of VDR localization, nuclear translocation and DNA binding activity revealed no in vitro age-related changes. Furthermore, calcitriol (10(-8)M) treatment of early-passage osteoblastic......Adequate responses to various hormones, such as 1,25-dihydroxyvitamin D(3) (calcitriol) are a prerequisite for optimal osteoblast functions. We have previously characterized several human diploid osteoblastic cell lines that exhibit typical in vitro aging characteristics during long...

Biocompatibility evaluation of HDPE-UHMWPE reinforced β-TCP nanocomposites using highly purified human osteoblast cells.

Science.gov (United States)

Shokrgozar, M A; Farokhi, M; Rajaei, F; Bagheri, M H A; Azari, Sh; Ghasemi, I; Mottaghitalab, F; Azadmanesh, K; Radfar, J

2010-12-15

Biocompatibility of β-TCP/HDPE-UHMWPE nanocomposite as a new bone substitute material was evaluated by using highly purified human osteoblast cells. Human osteoblast cells were isolated from bone tissue and characterized by immunofluorescence Staining before and after purification using magnetic bead system. Moreover, proliferation, alkaline phosphatase production, cell attachment, calcium deposition, gene expression, and morphology of osteoblast cells on β-TCP/HDPE-UHMWPE nanocomposites were evaluated. The results have shown that the human osteoblast cells were successfully purified and were suitable for subsequent cell culturing process. The high proliferation rate of osteoblast cells on β-TCP/HDPE-UHMWPE nanocomposite confirmed the great biocompatibility of the scaffold. Expression of bone-specific genes was taken place after the cells were incubated in composite extract solutions. Furthermore, osteoblast cells were able to mineralize the matrix next to composite samples. Scanning electron microscopy demonstrated that cells had normal morphology on the scaffold. Thus, these results indicated that the nanosized β-TCP/HDPE-UHMWPE blend composites could be potential scaffold, which is used in bone tissue engineering. Copyright © 2010 Wiley Periodicals, Inc.

Basic reactions of osteoblasts on structured material surfaces

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U. Meyer

2005-04-01

Full Text Available In order to assess how bone substitute materials determine bone formation in vivo it is useful to understand the mechanisms of the material surface/tissue interaction on a cellular level. Artificial materials are used in two applications, as biomaterials alone or as a scaffold for osteoblasts in a tissue engineering approach. Recently, many efforts have been undertaken to improve bone regeneration by the use of structured material surfaces. In vitro studies of bone cell responses to artificial materials are the basic tool to determine these interactions. Surface properties of materials surfaces as well as biophysical constraints at the biomaterial surface are of major importance since these features will direct the cell responses. Studies on osteoblast-like cell reactivity towards materials will have to focus on the different steps of protein and cell reactions towards defined surface properties. The introduction of new techniques allows nowadays the fabrication of materials with ordered surface structures. This paper gives a review of present knowledge on the various stages of osteoblast reactions on material surfaces, focused on basic cell events under in vitro conditions. Special emphasis is given to cellular reactions towards ordered nano-sized topographies.

Biocompatibility and Inflammatory Potential of Titanium Alloys Cultivated with Human Osteoblasts, Fibroblasts and Macrophages

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Markhoff, Jana; Krogull, Martin; Schulze, Christian; Rotsch, Christian; Hunger, Sandra; Bader, Rainer

2017-01-01

The biomaterials used to maintain or replace functions in the human body consist mainly of metals, ceramics or polymers. In orthopedic surgery, metallic materials, especially titanium and its alloys, are the most common, due to their excellent mechanical properties, corrosion resistance, and biocompatibility. Aside from the established Ti6Al4V alloy, shape memory materials such as nickel-titanium (NiTi) have risen in importance, but are also discussed because of the adverse effects of nickel ions. These might be reduced by specific surface modifications. In the present in vitro study, the osteoblastic cell line MG-63 as well as primary human osteoblasts, fibroblasts, and macrophages were cultured on titanium alloys (forged Ti6Al4V, additive manufactured Ti6Al4V, NiTi, and Diamond-Like-Carbon (DLC)-coated NiTi) to verify their specific biocompatibility and inflammatory potential. Additive manufactured Ti6Al4V and NiTi revealed the highest levels of metabolic cell activity. DLC-coated NiTi appeared as a suitable surface for cell growth, showing the highest collagen production. None of the implant materials caused a strong inflammatory response. In general, no distinct cell-specific response could be observed for the materials and surface coating used. In summary, all tested titanium alloys seem to be biologically appropriate for application in orthopedic surgery. PMID:28772412

Biocompatibility and Inflammatory Potential of Titanium Alloys Cultivated with Human Osteoblasts, Fibroblasts and Macrophages

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Jana Markhoff

2017-01-01

Full Text Available The biomaterials used to maintain or replace functions in the human body consist mainly of metals, ceramics or polymers. In orthopedic surgery, metallic materials, especially titanium and its alloys, are the most common, due to their excellent mechanical properties, corrosion resistance, and biocompatibility. Aside from the established Ti6Al4V alloy, shape memory materials such as nickel-titanium (NiTi have risen in importance, but are also discussed because of the adverse effects of nickel ions. These might be reduced by specific surface modifications. In the present in vitro study, the osteoblastic cell line MG-63 as well as primary human osteoblasts, fibroblasts, and macrophages were cultured on titanium alloys (forged Ti6Al4V, additive manufactured Ti6Al4V, NiTi, and Diamond-Like-Carbon (DLC-coated NiTi to verify their specific biocompatibility and inflammatory potential. Additive manufactured Ti6Al4V and NiTi revealed the highest levels of metabolic cell activity. DLC-coated NiTi appeared as a suitable surface for cell growth, showing the highest collagen production. None of the implant materials caused a strong inflammatory response. In general, no distinct cell-specific response could be observed for the materials and surface coating used. In summary, all tested titanium alloys seem to be biologically appropriate for application in orthopedic surgery.

BMP-2 Induced Expression of Alx3 That Is a Positive Regulator of Osteoblast Differentiation.

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Takashi Matsumoto

Full Text Available Bone morphogenetic proteins (BMPs regulate many aspects of skeletal development, including osteoblast and chondrocyte differentiation, cartilage and bone formation, and cranial and limb development. Among them, BMP-2, one of the most potent osteogenic signaling molecules, stimulates osteoblast differentiation, while it inhibits myogenic differentiation in C2C12 cells. To evaluate genes involved in BMP-2-induced osteoblast differentiation, we performed cDNA microarray analyses to compare BMP-2-treated and -untreated C2C12 cells. We focused on Alx3 (aristaless-like homeobox 3 which was clearly induced during osteoblast differentiation. Alx3, a homeobox gene related to the Drosophilaaristaless gene, has been linked to developmental functions in craniofacial structures and limb development. However, little is known about its direct relationship with bone formation. In the present study, we focused on the mechanisms of Alx3 gene expression and function during osteoblast differentiation induced by BMP-2. In C2C12 cells, BMP-2 induced increase of Alx3 gene expression in both time- and dose-dependent manners through the BMP receptors-mediated SMAD signaling pathway. In addition, silencing of Alx3 by siRNA inhibited osteoblast differentiation induced by BMP-2, as showed by the expressions of alkaline phosphatase (Alp, Osteocalcin, and Osterix, while over-expression of Alx3 enhanced osteoblast differentiation induced by BMP-2. These results indicate that Alx3 expression is enhanced by BMP-2 via the BMP receptors mediated-Smad signaling and that Alx3 is a positive regulator of osteoblast differentiation induced by BMP-2.

Monosodium urate monohydrate crystals inhibit osteoblast viability and function: implications for development of bone erosion in gout.

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Chhana, Ashika; Callon, Karen E; Pool, Bregina; Naot, Dorit; Watson, Maureen; Gamble, Greg D; McQueen, Fiona M; Cornish, Jillian; Dalbeth, Nicola

2011-09-01

Bone erosion is a common manifestation of chronic tophaceous gout. To investigate the effects of monosodium urate monohydrate (MSU) crystals on osteoblast viability and function. The MTT assay and flow cytometry were used to assess osteoblast cell viability in the MC3T3-E1 and ST2 osteoblast-like cell lines, and primary rat and primary human osteoblasts cultured with MSU crystals. Quantitative real-time PCR and von Kossa stained mineralised bone formation assays were used to assess the effects of MSU crystals on osteoblast differentiation using MC3T3-E1 cells. The numbers of osteoblasts and bone lining cells were quantified in bone samples from patients with gout. MSU crystals rapidly reduced viability in all cell types in a dose-dependent manner. The inhibitory effect on cell viability was independent of crystal phagocytosis and was not influenced by differing crystal length or addition of serum. Long-term culture of MC3T3-E1 cells with MSU crystals showed a reduction in mineralisation and decreased mRNA expression of genes related to osteoblast differentiation such as Runx2, Sp7 (osterix), Ibsp (bone sialoprotein), and Bglap (osteocalcin). Fewer osteoblast and lining cells were present on bone directly adjacent to gouty tophus than bone unaffected by tophus in patients with gout. MSU crystals have profound inhibitory effects on osteoblast viability and differentiation. These data suggest that bone erosion in gout occurs at the tophus-bone interface through alteration of physiological bone turnover, with both excessive osteoclast formation, and reduced osteoblast differentiation from mesenchymal stem cells.

UV-killed Staphylococcus aureus enhances adhesion and differentiation of osteoblasts on bone-associated biomaterials.

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Somayaji, Shankari N; Huet, Yvette M; Gruber, Helen E; Hudson, Michael C

2010-11-01

Titanium alloys (Ti) are the preferred material for orthopedic applications. However, very often, these metallic implants loosen over a long period and mandate revision surgery. For implant success, osteoblasts must adhere to the implant surface and deposit a mineralized extracellular matrix (ECM). Here, we utilized UV-killed Staphylococcus aureus as a novel osteoconductive coating for Ti surfaces. S. aureus expresses surface adhesins capable of binding to bone and biomaterials directly. Furthermore, interaction of S. aureus with osteoblasts activates growth factor-related pathways that potentiate osteogenesis. Although UV-killed S. aureus cells retain their bone-adhesive ability, they do not stimulate significant immune modulator expression. All of the abovementioned properties were utilized for a novel implant coating so as to promote osteoblast recruitment and subsequent cell functions on the bone-implant interface. In this study, osteoblast adhesion, proliferation, and mineralized ECM synthesis were measured on Ti surfaces coated with fibronectin with and without UV-killed bacteria. Osteoblast adhesion was enhanced on Ti alloy surfaces coated with bacteria compared to uncoated surfaces, while cell proliferation was sustained comparably on both surfaces. Osteoblast markers such as collagen, osteocalcin, alkaline phosphatase activity, and mineralized nodule formation were increased on Ti alloy coated with bacteria compared to uncoated surfaces.

The Effects of Orbital Spaceflight on Human Osteoblastic Cell Physiology and Gene Expression

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Turner, R. T.

1999-01-01

The purpose of the proposed study is to establish whether changes in gravitational loading have a direct effect on osteoblasts to regulate TGF-6 expression. The effects of spaceflight and reloading on TGF-B MRNA and peptide levels will be studied in a newly developed line of immortalized human fetal osteoblasts (HFOB) transfected with an SV-40 temperature dependent mutant to generate proliferating, undifferentiated hFOB cells at 33-34 C and a non-proliferating, differentiated HFOB cells at 37-39'C. Unlike previous cell culture models, HFOB cells have unlimited proliferative capacity yet can be precisely regulated to differentiate into mature cells which express mature osteoblast function. If isolated osteoblasts respond to changes in mechanical loading in a manner similar to their response in animals, the cell system could provide a powerful model to investigate the signal transduction pathway for gravitational loading.

Electrical Polarization of Titanium Surfaces for the Enhancement of Osteoblast Differentiation

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Gittens, Rolando A.; Olivares-Navarrete, Rene; Rettew, Robert; Butera, Robert J.; Alamgir, Faisal M.; Boyan, Barbara D.; Schwartz, Zvi

2014-01-01

Electrical stimulation has been used clinically to promote bone regeneration in cases of fractures with delayed union or nonunion, with several in vitro and in vivo reports suggesting its beneficial effects on bone formation. However, the use of electrical stimulation of titanium (Ti) implants to enhance osseointegration is less understood, in part because of the few in vitro models that attempt to represent the in vivo environment. In this article, the design of a new in vitro system that allows direct electrical stimulation of osteoblasts through their Ti substrates without the flow of exogenous currents through the media is presented, and the effect of applied electrical polarization on osteoblast differentiation and local factor production was evaluated. A custom-made polycarbonate tissue culture plate was designed to allow electrical connections directly underneath Ti disks placed inside the wells, which were supplied with electrical polarization ranging from 100 to 500 mV to stimulate MG63 osteoblasts. Our results show that electrical polarization applied directly through Ti substrates on which the cells are growing in the absence of applied electrical currents may increase osteoblast differentiation and local factor production in a voltage-dependent manner. PMID:23996899

Enhanced osteoblast adhesion to drug-coated anodized nanotubular titanium surfaces

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George E Aninwene II

2008-06-01

Full Text Available George E Aninwene II1, Chang Yao2, Thomas J Webster21Department of Biochemical Engineering, University of Maryland, Baltimore, MD; 2Division of Engineering, Brown University, Providence, RI, USAAbstract: Current orthopedic implants have functional lifetimes of only 10–15 years due to a variety of reasons including infection, extensive inflammation, and overall poor osseointegration (or a lack of prolonged bonding of the implant to juxtaposed bone. To improve properties of titanium for orthopedic applications, this study anodized and subsequently coated titanium with drugs known to reduce infection (penicillin/streptomycin and inflammation (dexamethasone using simple physical adsorption and the deposition of such drugs from simulated body fluid (SBF. Results showed improved drug elution from anodized nanotubular titanium when drugs were coated in the presence of SBF for up to 3 days. For the first time, results also showed that the simple physical adsorption of both penicillin/streptomycin and dexamethasone on anodized nanotubular titanium improved osteoblast numbers after 2 days of culture compared to uncoated unanodized titanium. In addition, results showed that depositing such drugs in SBF on anodized titanium was a more efficient method to promote osteoblast numbers compared to physical adsorption for up to 2 days of culture. In addition, osteoblast numbers increased on anodized titanium coated with drugs in SBF for up to 2 days of culture compared to unanodized titanium. In summary, compared to unanodized titanium, this preliminary study provided unexpected evidence of greater osteoblast numbers on anodized titanium coated with either penicillin/streptomycin or dexamethasone using simple physical adsorption or when coated with SBF; results which suggest the need for further research on anodized titanium orthopedic implants possessing drug-eluting nanotubes.Keywords: anodization, titanium, adhesion, simulated body fluid, nanotubes

Chondrocytic Atf4 regulates osteoblast differentiation and function via Ihh.

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Wang, Weiguang; Lian, Na; Ma, Yun; Li, Lingzhen; Gallant, Richard C; Elefteriou, Florent; Yang, Xiangli

2012-02-01

Atf4 is a leucine zipper-containing transcription factor that activates osteocalcin (Ocn) in osteoblasts and indian hedgehog (Ihh) in chondrocytes. The relative contribution of Atf4 in chondrocytes and osteoblasts to the regulation of skeletal development and bone formation is poorly understood. Investigations of the Atf4(-/-);Col2a1-Atf4 mouse model, in which Atf4 is selectively overexpressed in chondrocytes in an Atf4-null background, demonstrate that chondrocyte-derived Atf4 regulates osteogenesis during development and bone remodeling postnatally. Atf4 overexpression in chondrocytes of the Atf4(-/-);Col2a1-Atf4 double mutants corrects the reduction in stature and limb in Atf4(-/-) embryos and rectifies the decrease in Ihh expression, Hh signaling, proliferation and accelerated hypertrophy that characterize the Atf4(-/-) developing growth plate cartilages. Unexpectedly, this genetic manipulation also restores the expression of osteoblastic marker genes, namely Ocn and bone sialoprotein, in Atf4(-/-) developing bones. In Atf4(-/-);Col2a1-Atf4 adult mice, all the defective bone parameters found in Atf4(-/-) mice, including bone volume, trabecular number and thickness, and bone formation rate, are rescued. In addition, the conditioned media of ex vivo cultures from wild-type or Atf4(-/-);Col2a1-Atf4, but not Atf4(-/-) cartilage, corrects the differentiation defects of Atf4(-/-) bone marrow stromal cells and Ihh-blocking antibody eliminates this effect. Together, these data indicate that Atf4 in chondrocytes is required for normal Ihh expression and for its paracrine effect on osteoblast differentiation. Therefore, the cell-autonomous role of Atf4 in chondrocytes dominates the role of Atf4 in osteoblasts during development for the control of early osteogenesis and skeletal growth.

Activating AMP-activated protein kinase by an α1 selective activator compound 13 attenuates dexamethasone-induced osteoblast cell death

International Nuclear Information System (INIS)

Guo, Shiguang; Mao, Li; Ji, Feng; Wang, Shouguo; Xie, Yue; Fei, Haodong; Wang, Xiao-dong

2016-01-01

Excessive glucocorticoid (GC) usage may lead to non-traumatic femoral head osteonecrosis. Dexamethasone (Dex) exerts cytotoxic effect to cultured osteoblasts. Here, we investigated the potential activity of Compound 13 (C13), a novel α1 selective AMP-activated protein kinase (AMPK) activator, against the process. Our data revealed that C13 pretreatment significantly attenuated Dex-induced apoptosis and necrosis in both osteoblastic-like MC3T3-E1 cells and primary murine osteoblasts. AMPK activation mediated C13′ cytoprotective effect in osteoblasts. The AMPK inhibitor Compound C, shRNA-mediated knockdown of AMPKα1, or dominant negative mutation of AMPKα1 (T172A) almost abolished C13-induced AMPK activation and its pro-survival effect in osteoblasts. On the other hand, forced AMPK activation by adding AMPK activator A-769662 or exogenous expression a constitutively-active (ca) AMPKα1 (T172D) mimicked C13's actions and inhibited Dex-induced osteoblast cell death. Meanwhile, A-769662 or ca-AMPKα1 almost nullified C13's activity in osteoblast. Further studies showed that C13 activated AMPK-dependent nicotinamide adenine dinucleotide phosphate (NADPH) pathway to inhibit Dex-induced reactive oxygen species (ROS) production in MC3T3-E1 cells and primary murine osteoblasts. Such effects by C13 were almost reversed by Compound C or AMPKα1 depletion/mutation. Together, these results suggest that C13 alleviates Dex-induced osteoblast cell death via activating AMPK signaling pathway. - Highlights: • Compound 13 (C13) attenuates dexamethasone (Dex)-induced osteoblast cell death. • C13-induced cytoprotective effect against Dex in osteoblasts requires AMPK activation. • Forced AMPK activation protects osteoblasts from Dex, nullifying C13's activities. • C13 increases NADPH activity and inhibits Dex-induced oxidative stress in osteoblasts.

Activating AMP-activated protein kinase by an α1 selective activator compound 13 attenuates dexamethasone-induced osteoblast cell death

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Guo, Shiguang [Department of Intensive Care Unit, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an (China); Mao, Li [Department of Endocrinology, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an (China); Ji, Feng, E-mail: huaiaifengjidr@163.com [Department of Orthopedics, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an (China); Wang, Shouguo; Xie, Yue; Fei, Haodong [Department of Orthopedics, Huai' an First People' s Hospital, Nanjing Medical University, Huai' an (China); Wang, Xiao-dong, E-mail: xiaodongwangsz@163.com [The Center of Diagnosis and Treatment for Children' s Bone Diseases, The Children' s Hospital Affiliated to Soochow University, Suzhou (China)

2016-03-18

Excessive glucocorticoid (GC) usage may lead to non-traumatic femoral head osteonecrosis. Dexamethasone (Dex) exerts cytotoxic effect to cultured osteoblasts. Here, we investigated the potential activity of Compound 13 (C13), a novel α1 selective AMP-activated protein kinase (AMPK) activator, against the process. Our data revealed that C13 pretreatment significantly attenuated Dex-induced apoptosis and necrosis in both osteoblastic-like MC3T3-E1 cells and primary murine osteoblasts. AMPK activation mediated C13′ cytoprotective effect in osteoblasts. The AMPK inhibitor Compound C, shRNA-mediated knockdown of AMPKα1, or dominant negative mutation of AMPKα1 (T172A) almost abolished C13-induced AMPK activation and its pro-survival effect in osteoblasts. On the other hand, forced AMPK activation by adding AMPK activator A-769662 or exogenous expression a constitutively-active (ca) AMPKα1 (T172D) mimicked C13's actions and inhibited Dex-induced osteoblast cell death. Meanwhile, A-769662 or ca-AMPKα1 almost nullified C13's activity in osteoblast. Further studies showed that C13 activated AMPK-dependent nicotinamide adenine dinucleotide phosphate (NADPH) pathway to inhibit Dex-induced reactive oxygen species (ROS) production in MC3T3-E1 cells and primary murine osteoblasts. Such effects by C13 were almost reversed by Compound C or AMPKα1 depletion/mutation. Together, these results suggest that C13 alleviates Dex-induced osteoblast cell death via activating AMPK signaling pathway. - Highlights: • Compound 13 (C13) attenuates dexamethasone (Dex)-induced osteoblast cell death. • C13-induced cytoprotective effect against Dex in osteoblasts requires AMPK activation. • Forced AMPK activation protects osteoblasts from Dex, nullifying C13's activities. • C13 increases NADPH activity and inhibits Dex-induced oxidative stress in osteoblasts.

Blockade of Drp1 rescues oxidative stress-induced osteoblast dysfunction

Energy Technology Data Exchange (ETDEWEB)

Gan, Xueqi; Huang, Shengbin; Yu, Qing [Department of Pharmacology and Toxicology and Higuchi Bioscience Center, University of Kansas, Lawrence, KS, 66047 (United States); State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041 (China); Yu, Haiyang [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041 (China); Yan, Shirley ShiDu, E-mail: shidu@ku.edu [Department of Pharmacology and Toxicology and Higuchi Bioscience Center, University of Kansas, Lawrence, KS, 66047 (United States)

2015-12-25

Osteoblast dysfunction, induced by oxidative stress, plays a critical role in the pathophysiology of osteoporosis. However, the underlying mechanisms remain unclarified. Imbalance of mitochondrial dynamics has been closely linked to oxidative stress. Here, we reveal an unexplored role of dynamic related protein 1(Drp1), the major regulator in mitochondrial fission, in the oxidative stress-induced osteoblast injury model. We demonstrate that levels of phosphorylation and expression of Drp1 significantly increased under oxidative stress. Blockade of Drp1, through pharmaceutical inhibitor or gene knockdown, significantly protected against H{sub 2}O{sub 2}-induced osteoblast dysfunction, as shown by increased cell viability, improved cellular alkaline phosphatase (ALP) activity and mineralization and restored mitochondrial function. The protective effects of blocking Drp1 in H{sub 2}O{sub 2}-induced osteoblast dysfunction were evidenced by increased mitochondrial function and suppressed production of reactive oxygen species (ROS). These findings provide new insights into the role of the Drp1-dependent mitochondrial pathway in the pathology of osteoporosis, indicating that the Drp1 pathway may be targetable for the development of new therapeutic approaches in the prevention and the treatment of osteoporosis. - Highlights: • Oxidative stress is an early pathological event in osteoporosis. • Imbalance of mitochondrial dynamics are linked to oxidative stress in osteoporosis. • The role of the Drp1-dependent mitochondrial pathway in osteoporosis.

Sodium nitroprusside induces autophagic cell death in glutathione-depleted osteoblasts.

Science.gov (United States)

Son, Min Jeong; Lee, Seong-Beom; Byun, Yu Jeong; Lee, Hwa Ok; Kim, Ho-Shik; Kwon, Oh-Joo; Jeong, Seong-Whan

2010-01-01

Previous studies reported that high levels of nitric oxide (NO) induce apoptotic cell death in osteoblasts. We examined molecular mechanisms of cytotoxic injury induced by sodium nitroprusside (SNP), a NO donor, in both glutathione (GSH)-depleted and control U2-OS osteoblasts. Cell viability was reduced by much lower effective concentrations of SNP in GSH-depleted cells compared to normal cells. The data suggest that the level of intracellular GSH is critical in SNP-induced cell death processes of osteoblasts. The level of oxidative stress due to SNP treatments doubled in GSH-depleted cells when measured with fluorochrome H2DCFDA. Pretreatment with the NO scavenger PTIO preserved the viability of cells treated with SNP. Viability of cells treated with SNP was recovered by pretreatment with Wortmannin, an autophagy inhibitor, but not by pretreatment with zVAD-fmk, a pan-specific caspase inhibitor. Large increases of LC3-II were shown by immunoblot analysis of the SNP-treated cells, and the increase was blocked by pretreatment with PTIO or Wortmannin; this implies that under GSH-depleted conditions SNP induces different molecular signaling that lead to autophagic cell death. The ultrastructural morphology of SNP-treated cells in transmission electron microscopy showed numerous autophagic vacuoles. These data suggest NO produces oxidative stress and cellular damage that culminate in autophagic cell death of GSH-depleted osteoblasts. Copyright 2010 Wiley Periodicals, Inc.

Differentiation of bovine spermatogonial stem cells into osteoblasts.

Science.gov (United States)

Qasemi-Panahi, Babak; Tajik, Parviz; Movahedin, Mansoureh; Moghaddam, Gholamali; Barzgar, Younes; Heidari-Vala, Hamed

2011-07-01

Spermatogonial Stem Cell (SSC) technologies provide multiple opportunities for research in the field of biotechnology and regenerative medicine. The therapeutic use of Embryonic Stem Cells (ESCs) is restricted due to severe ethical and immunological concerns. Therefore, we need a new pluripotent cell type. Despite well-known role of germ cells in the gametogenesis, some facts apparently show their multipotentiality. In the present study, bovine SSCs were co-cultured with Sertoli cell for 7 days. Sertoli cells and SSCs were identified by Vimentin and Oct-4 immunocytochemical staining method, respectively. In order to differentiate SSCs into osteoblasts, we used consecutive inducer media without separation of the colonies. We characterized osteoblasts using Alizarin red staining.

Lysophosphatidic acid induces chemotaxis in MC3T3-E1 osteoblastic cells

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Masiello, Lisa M.; Fotos, Joseph S.; Galileo, Deni S.; Karin, Norm J.

2006-07-01

Lysophosphatidic acid (LPA) is a bioactive lipid that has pleiotropic effects on a variety of cell types and enhances the migration of endothelial and cancer cells, but it is not known if this lipid can alter osteoblast motility. We performed transwell migration assays using MC3T3-E1 osteoblastic cells and found LPA to be a potent chemotactic agent. Quantitative time-lapse video analysis of osteoblast migration after wounds were introduced into cell monolayers indicated that LPA stimulated both migration velocity and the average migration distance per cell. LPA also elicited substantial changes in cell shape and actin cytoskeletal structure; lipid-treated cells contained fewer stress fibers and displayed long membrane processes that were enriched in F-actin. Quantitative RT-PCR analysis showed that MC3T3-E1 cells express all four known LPA-specific G protein-coupled receptors (LPA1-LPA4) with a relative mRNA abundance of LPA1 > LPA4 > LPA2 >> LPA3. LPA-induced changes in osteoblast motility and morphology were antagonized by both pertussis toxin and Ki16425, a subtype-specific blocker of LPA1 and LPA3 receptor function. Cell migration in many cell types is linked to changes in intracellular Ca2+. Ki16425 also inhibited LPA-induced Ca2+ signaling in a dose-dependent manner, suggesting a link between LPA-induced Ca2+ transients and osteoblast chemotaxis. Our data show that LPA stimulates MC3T3-E1 osteoblast motility via a mechanism that is linked primarily to the G protein-coupled receptor LPA1.

Low bone mass and changes in the osteocyte network in mice lacking autophagy in the osteoblast lineage.

Science.gov (United States)

Piemontese, Marilina; Onal, Melda; Xiong, Jinhu; Han, Li; Thostenson, Jeff D; Almeida, Maria; O'Brien, Charles A

2016-04-11

Autophagy maintains cell function and homeostasis by recycling intracellular components. This process is also required for morphological changes associated with maturation of some cell types. Osteoblasts are bone forming cells some of which become embedded in bone and differentiate into osteocytes. This transformation includes development of long cellular projections and a reduction in endoplasmic reticulum and mitochondria. We examined the role of autophagy in osteoblasts by deleting Atg7 using an Osterix1-Cre transgene, which causes recombination in osteoblast progenitors and their descendants. Mice lacking Atg7 in the entire osteoblast lineage had low bone mass and fractures associated with reduced numbers of osteoclasts and osteoblasts. Suppression of autophagy also reduced the amount of osteocyte cellular projections and led to retention of endoplasmic reticulum and mitochondria in osteocytes. These results demonstrate that autophagy in osteoblasts contributes to skeletal homeostasis and to the morphological changes associated with osteocyte formation.

Wnt3a induces the expression of acetylcholinesterase during osteoblast differentiation via the Runx2 transcription factor.

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Xu, Miranda L; Bi, Cathy W C; Liu, Etta Y L; Dong, Tina T X; Tsim, Karl W K

2017-07-28

Acetylcholinesterase (AChE) hydrolyzes acetylcholine to terminate cholinergic transmission in neurons. Apart from this AChE activity, emerging evidence suggests that AChE could also function in other, non-neuronal cells. For instance, in bone, AChE exists as a proline-rich membrane anchor (PRiMA)-linked globular form in osteoblasts, in which it is proposed to play a noncholinergic role in differentiation. However, this hypothesis is untested. Here, we found that in cultured rat osteoblasts, AChE expression was increased in parallel with osteoblastic differentiation. Because several lines of evidence indicate that AChE activity in osteoblast could be triggered by Wnt/β-catenin signaling, we added recombinant human Wnt3a to cultured osteoblasts and found that this addition induced expression of the ACHE gene and protein product. This Wnt3a-induced AChE expression was blocked by the Wnt-signaling inhibitor Dickkopf protein-1 (DKK-1). We hypothesized that the Runt-related transcription factor 2 (Runx2), a downstream transcription factor in Wnt/β-catenin signaling, is involved in AChE regulation in osteoblasts, confirmed by the identification of a Runx2-binding site in the ACHE gene promoter, further corroborated by ChIP. Of note, Runx2 overexpression in osteoblasts induced AChE expression and activity of the ACHE promoter tagged with the luciferase gene. Moreover, deletion of the Runx2-binding site in the ACHE promoter reduced its activity during osteoblastic differentiation, and addition of 5-azacytidine and trichostatin A to differentiating osteoblasts affected AChE expression, suggesting epigenetic regulation of the ACHE gene. We conclude that AChE plays a role in osteoblastic differentiation and is regulated by both Wnt3a and Runx2. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Acerogenin A, a natural compound isolated from Acer nikoense Maxim, stimulates osteoblast differentiation through bone morphogenetic protein action

International Nuclear Information System (INIS)

Kihara, Tasuku; Ichikawa, Saki; Yonezawa, Takayuki; Lee, Ji-Won; Akihisa, Toshihiro; Woo, Je Tae; Michi, Yasuyuki; Amagasa, Teruo; Yamaguchi, Akira

2011-01-01

Research highlights: → Acerogenin A stimulated osteoblast differentiation in osteogenic cells. → Acerogenin A-induced osteoblast differentiation was inhibited by noggin. → Acerogenin A increased Bmp-2, Bmp-4 and Bmp-7 mRNA expression in MC3T3-E1 cells. → Acerogenin A is a candidate agent for stimulating bone formation. -- Abstract: We investigated the effects of acerogenin A, a natural compound isolated from Acer nikoense Maxim, on osteoblast differentiation by using osteoblastic cells. Acerogenin A stimulated the cell proliferation of MC3T3-E1 osteoblastic cells and RD-C6 osteoblastic cells (Runx2-deficient cell line). It also increased alkaline phosphatase activity in MC3T3-E1 and RD-C6 cells and calvarial osteoblastic cells isolated from the calvariae of newborn mice. Acerogenin A also increased the expression of mRNAs related to osteoblast differentiation, including Osteocalcin, Osterix and Runx2 in MC3T3-E1 cells and primary osteoblasts: it also stimulated Osteocalcin and Osterix mRNA expression in RD-C6 cells. The acerogenin A treatment for 3 days increased Bmp-2, Bmp-4, and Bmp-7 mRNA expression levels in MC3T3-E1 cells. Adding noggin, a BMP specific-antagonist, inhibited the acerogenin A-induced increase in the Osteocalcin, Osterix and Runx2 mRNA expression levels. These results indicated that acerogenin A stimulates osteoblast differentiation through BMP action, which is mediated by Runx2-dependent and Runx2-independent pathways.

Bone sialoprotein II synthesized by cultured osteoblasts contains tyrosine sulfate

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Ecarot-Charrier, B.; Bouchard, F.; Delloye, C.

1989-01-01

Isolated mouse osteoblasts that retain their osteogenic activity in culture were incubated with [35S] sulfate. Two radiolabeled proteins, in addition to proteoglycans, were extracted from the calcified matrix of osteoblast cultures. All the sulfate label in both proteins was in the form of tyrosine sulfate as assessed by amino acid analysis and thin layer chromatography following alkaline hydrolysis. The elution behavior on DEAE-Sephacel of the major sulfated protein and the apparent Mr on sodium dodecyl sulfate gels were characteristic of bone sialoprotein II extracted from rat. This protein was shown to cross-react with an antiserum raised against bovine bone sialoprotein II, indicating that bone sialoprotein II synthesized by cultured mouse osteoblasts is a tyrosine-sulfated protein. The minor sulfated protein was tentatively identified as bone sialoprotein I or osteopontin based on its elution properties on DEAE-Sephacel and anomalous behavior on sodium dodecyl sulfate gels similar to those reported for rat bone sialoprotein I

Human osteoblast cells: isolation, characterization, and growth on polymers for musculoskeletal tissue engineering.

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El-Amin, Saadiq F; Botchwey, Edward; Tuli, Richard; Kofron, Michelle D; Mesfin, Addisu; Sethuraman, Swaminathan; Tuan, Rocky S; Laurencin, Cato T

2006-03-01

We performed a detailed examination of the isolation, characterization, and growth of human osteoblast cells derived from trabecular bone. We further examined the morphology, phenotypic gene expression, mineralization,and growth of these human osteoblasts on polyester polymers used for musculoskeletal tissue engineering. Polylactic-co-glycolic acid [PLAGA (85:15, 50:50, 75:25)], and poly-lactic acid (L-PLA, D,L-PLA) were examined. The osteoblastic expression of key phenotypic markers osteocalcin, alkaline phosphatase, collagen, and bone sialoprotein at 4 and 8 weeks was examined. Reverse transcription-polymerase chain reaction studies revealed that trabecular-derived osteoblasts were positive for all markers evaluated with higher levels expressed over long-term culture. These cells also revealed mineralization and maturation as evidenced by energy dispersive X-ray analysis and scanning electron microscopy. Growth studies on PLAGA at 50:50,75:25, and 85:15 ratios and PLA in the L and DL isoforms revealed that human osteoblasts actively grew, with significantly higher cell numbers attached to scaffolds composed of PLAGA 50:50 in the short term and PLAGA 85:15 in the long term compared with PLA (p < 0.05). We believe human cell adhesion among these polymeric materials may be dependent on differences in cellular integrin expression and extracellular matrix protein elaboration. (c) 2005 Wiley Periodicals, Inc.

Osteoblast CFTR inactivation reduces differentiation and osteoprotegerin expression in a mouse model of cystic fibrosis-related bone disease.

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Michael S Stalvey

Full Text Available Low bone mass and increased fracture risk are recognized complications of cystic fibrosis (CF. CF-related bone disease (CFBD is characterized by uncoupled bone turnover--impaired osteoblastic bone formation and enhanced osteoclastic bone resorption. Intestinal malabsorption, vitamin D deficiency and inflammatory cytokines contribute to CFBD. However, epidemiological investigations and animal models also support a direct causal link between inactivation of skeletal cystic fibrosis transmembrane regulator (CFTR, the gene that when mutated causes CF, and CFBD. The objective of this study was to examine the direct actions of CFTR on bone. Expression analyses revealed that CFTR mRNA and protein were expressed in murine osteoblasts, but not in osteoclasts. Functional studies were then performed to investigate the direct actions of CFTR on osteoblasts using a CFTR knockout (Cftr-/- mouse model. In the murine calvarial organ culture assay, Cftr-/- calvariae displayed significantly less bone formation and osteoblast numbers than calvariae harvested from wildtype (Cftr+/+ littermates. CFTR inactivation also reduced alkaline phosphatase expression in cultured murine calvarial osteoblasts. Although CFTR was not expressed in murine osteoclasts, significantly more osteoclasts formed in Cftr-/- compared to Cftr+/+ bone marrow cultures. Indirect regulation of osteoclastogenesis by the osteoblast through RANK/RANKL/OPG signaling was next examined. Although no difference in receptor activator of NF-κB ligand (Rankl mRNA was detected, significantly less osteoprotegerin (Opg was expressed in Cftr-/- compared to Cftr+/+ osteoblasts. Together, the Rankl:Opg ratio was significantly higher in Cftr-/- murine calvarial osteoblasts contributing to a higher osteoclastogenesis potential. The combined findings of reduced osteoblast differentiation and lower Opg expression suggested a possible defect in canonical Wnt signaling. In fact, Wnt3a and PTH-stimulated canonical Wnt

Gold nanoparticles stimulate differentiation and mineralization of primary osteoblasts through the ERK/MAPK signaling pathway

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Zhang, Dawei; Liu, Dandan; Zhang, Jinchao; Fong, Chichun; Yang, Mengsu

2014-01-01

Gold nanoparticles (AuNPs) have shown great promise for a variety of applications, including chemistry, biology, and medicine. Recently, AuNPs have found promising applications in cartilage and bone repair. However, to realize the above promised applications, more work needs to be carried out to clarify the interactions between biological systems and AuNPs. In the present study, primary osteoblasts were used to evaluate the biocompatibility of 20-nm and 40-nm AuNPs, including morphology, proliferation, differentiation, gene and protein expression, and the underlying mechanisms. The results demonstrated that AuNPs were taken up by osteoblasts and aggregated in perinuclear compartment and vescular structures, but no morphological changes were observed. AuNPs could significantly promote the proliferation of osteoblasts, enhance the ALP activities, and increase the number of bone nodules and calcium content in vitro. In addition, the expression of BMP-2, Runx-2, OCN and Col-1 was remarkably up-regulated in the presence of AuNPs. It is noteworthy that 20-nm AuNPs are more potent than 40-nm AuNPs in regulating osteoblast activities. Besides, AuNPs increased the level of ERK phosphorylation/total ERK, suggesting the activation of ERK/MAPK pathway is involved in above activities. In conclusion, AuNPs exhibited great biocompatibility with osteoblasts, and have tremendous potential to be used as drug and/or gene delivery carrier for bone and tissue engineering in the future. - Highlights: • AuNPs aggregated in perinuclear compartment and vescular structures of osteoblasts. • AuNPs up-regulated the expression of Runx-2, BMP-2, OCN and Col I of osteoblasts. • AuNPs enhanced osteoblast differentiation by activating the ERK/MAPK pathway. • The size of nanoparticles may be important to exhibit their biological effects. • AuNPs have tremendous potential in bone and tissue engineering in future

Osteoblast and osteoclast behaviors in the turnover of attachment bones during medaka tooth replacement.

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Mantoku, Akiko; Chatani, Masahiro; Aono, Kazushi; Inohaya, Keiji; Kudo, Akira

2016-01-15

Tooth replacement in polyphyodont is a well-organized system for maintenance of homeostasis of teeth, containing the dynamic structural change in skeletal tissues such as the attachment bone, which is the supporting element of teeth. Histological analyses have revealed the character of tooth replacement, however, the cellular mechanism of how skeletal tissues are modified during tooth replacement is largely unknown. Here, we showed the important role of osteoblasts for controlling osteoclasts to modify the attachment bone during tooth replacement in medaka pharyngeal teeth, coupled with an osterix-DsRed/TRAP-GFP transgenic line to visualize osteoblasts and osteoclasts. In the turnover of the row of attachment bones, these bones were resorbed at the posterior side where most developed functional teeth were located, and generated at the anterior side where teeth were newly erupted, which caused continuous tooth replacement. In the cellular analysis, osteoclasts and osteoblasts were located at attachment bones separately, since mature osteoclasts were localized at the resorbing side and osteoblasts gathered at the generating side. To demonstrate the role of osteoclasts in tooth replacement, we established medaka made deficient in c-fms-a by TALEN. c-fms-a deficient medaka showed hyperplasia of attachment bones along with reduced bone resorption accompanied by a low number of TRAP-positive osteoclasts, indicating an important role of osteoclasts in the turnover of attachment bones. Furthermore, nitroreductase-mediated osteoblast-specific ablation induced disappearance of osteoclasts, indicating that osteoblasts were essential for maintenance of osteoclasts for the proper turnover. Taken together, our results suggested that the medaka attachment bone provides the model to understand the cellular mechanism for tooth replacement, and that osteoblasts act in the coordination of bone morphology by supporting osteoclasts. Copyright © 2015 Elsevier Inc. All rights reserved.

Mechanism involved in enhancement of osteoblast differentiation by hyaluronic acid

International Nuclear Information System (INIS)

Kawano, Michinao; Ariyoshi, Wataru; Iwanaga, Kenjiro; Okinaga, Toshinori; Habu, Manabu; Yoshioka, Izumi; Tominaga, Kazuhiro; Nishihara, Tatsuji

2011-01-01

Research highlights: → In this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. → MG63 cells were incubated with BMP-2 and HA for various time periods. → Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. → HA enhanced BMP-2 induces osteoblastic differentiation in MG63 cells via down-regulation of BMP-2 antagonists and ERK phosphorylation. -- Abstract: Objectives: Bone morphogenetic protein-2 (BMP-2) is expected to be utilized to fill bone defects and promote healing of fractures. However, it is unable to generate an adequate clinical response for use in bone regeneration. Recently, it was reported that glycosaminoglycans, including heparin, heparan sulfate, keratan sulfate, dermatan sulfate, chondroitin-4-sulfate, chondroitin-6-sulfate, and hyaluronic acid (HA), regulate BMP-2 activity, though the mechanism by which HA regulates osteogenic activities has not been fully elucidated. The aim of this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. Materials and methods: Monolayer cultures of osteoblastic lineage MG63 cells were incubated with BMP-2 and HA for various time periods. To determine osteoblastic differentiation, alkaline phosphatase (ALP) activity in the cell lysates was quantified. Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by Western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. To further elucidate the role of HA in enhancement of BMP-2-induced Smad signaling, mRNA expressions of the BMP-2 receptor antagonists noggin and follistatin were detected using real-time RT-PCR. Results: BMP-2-induced ALP activation, Smad 1/5/8 phosphorylation, and nuclear translocation

Mechanism involved in enhancement of osteoblast differentiation by hyaluronic acid

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Kawano, Michinao [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Ariyoshi, Wataru [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Iwanaga, Kenjiro [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Okinaga, Toshinori [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Habu, Manabu [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Yoshioka, Izumi [Division of Oral and Maxillofacial Surgery, Department of Medicine of Sensory and Motor Organs, University of Miyazaki, Kiyotake, Miyazaki 889-1692 (Japan); Tominaga, Kazuhiro [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Nishihara, Tatsuji, E-mail: tatsujin@kyu-dent.ac.jp [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, Kitakyushu 803-8580 (Japan)

2011-02-25

Research highlights: {yields} In this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. {yields} MG63 cells were incubated with BMP-2 and HA for various time periods. {yields} Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. {yields} HA enhanced BMP-2 induces osteoblastic differentiation in MG63 cells via down-regulation of BMP-2 antagonists and ERK phosphorylation. -- Abstract: Objectives: Bone morphogenetic protein-2 (BMP-2) is expected to be utilized to fill bone defects and promote healing of fractures. However, it is unable to generate an adequate clinical response for use in bone regeneration. Recently, it was reported that glycosaminoglycans, including heparin, heparan sulfate, keratan sulfate, dermatan sulfate, chondroitin-4-sulfate, chondroitin-6-sulfate, and hyaluronic acid (HA), regulate BMP-2 activity, though the mechanism by which HA regulates osteogenic activities has not been fully elucidated. The aim of this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. Materials and methods: Monolayer cultures of osteoblastic lineage MG63 cells were incubated with BMP-2 and HA for various time periods. To determine osteoblastic differentiation, alkaline phosphatase (ALP) activity in the cell lysates was quantified. Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by Western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. To further elucidate the role of HA in enhancement of BMP-2-induced Smad signaling, mRNA expressions of the BMP-2 receptor antagonists noggin and follistatin were detected using real-time RT-PCR. Results: BMP-2-induced ALP activation, Smad 1/5/8 phosphorylation, and

Palmitic Acid Induces Osteoblastic Differentiation in Vascular Smooth Muscle Cells through ACSL3 and NF-κB, Novel Targets of Eicosapentaenoic Acid

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Kageyama, Aiko; Matsui, Hiroki; Ohta, Masahiko; Sambuichi, Keisuke; Kawano, Hiroyuki; Notsu, Tatsuto; Imada, Kazunori; Yokoyama, Tomoyuki; Kurabayashi, Masahiko

2013-01-01

Free fatty acids (FFAs), elevated in metabolic syndrome and diabetes, play a crucial role in the development of atherosclerotic cardiovascular disease, and eicosapentaenoic acid (EPA) counteracts many aspects of FFA-induced vascular pathology. Although vascular calcification is invariably associated with atherosclerosis, the mechanisms involved are not completely elucidated. In this study, we tested the hypothesis that EPA prevents the osteoblastic differentiation and mineralization of vascular smooth muscle cells (VSMC) induced by palmitic acid (PA), the most abundant long-chain saturated fatty acid in plasma. PA increased and EPA abolished the expression of the genes for bone-related proteins, including bone morphogenetic protein (BMP)-2, Msx2 and osteopontin in human aortic smooth muscle cells (HASMC). Among the long-chain acyl-CoA synthetase (ACSL) subfamily, ACSL3 expression was predominant in HASMC, and PA robustly increased and EPA efficiently inhibited ACSL3 expression. Importantly, PA-induced osteoblastic differentiation was mediated, at least in part, by ACSL3 activation because acyl-CoA synthetase (ACS) inhibitor or siRNA targeted to ACSL3 completely prevented the PA induction of both BMP-2 and Msx2. Conversely, adenovirus-mediated ACSL3 overexpression enhanced PA-induced BMP-2 and Msx2 expression. In addition, EPA, ACSL3 siRNA and ACS inhibitor attenuated calcium deposition and caspase activation induced by PA. Notably, PA induced activation of NF-κB, and NF-κB inhibitor prevented PA-induction of osteoblastic gene expression and calcium deposition. Immunohistochemistry revealed the prominent expression of ACSL3 in VSMC and macrophages in human non-calcifying and calcifying atherosclerotic plaques from the carotid arteries. These results identify ACSL3 and NF-κB as mediators of PA-induced osteoblastic differentiation and calcium deposition in VSMC and suggest that EPA prevents vascular calcification by inhibiting such a new molecular pathway elicited

Ihh signaling is directly required for the osteoblast lineage in the endochondral skeleton.

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Long, Fanxin; Chung, Ung-il; Ohba, Shinsuke; McMahon, Jill; Kronenberg, Henry M; McMahon, Andrew P

2004-03-01

Indian hedgehog (Ihh) is indispensable for development of the osteoblast lineage in the endochondral skeleton. In order to determine whether Ihh is directly required for osteoblast differentiation, we have genetically manipulated smoothened (Smo), which encodes a transmembrane protein that is essential for transducing all Hedgehog (Hh) signals. Removal of Smo from perichondrial cells by the Cre-LoxP approach prevents formation of a normal bone collar and also abolishes development of the primary spongiosa. Analysis of chimeric embryos composed of wild-type and Smo(n/n) cells indicates that Smo(n/n) cells fail to contribute to osteoblasts in either the bone collar or the primary spongiosa but generate ectopic chondrocytes. In order to assess whether Ihh is sufficient to induce bone formation in vivo, we have analyzed the bone collar in the long bones of embryos in which Ihh was artificially expressed in all chondrocytes by the UAS-GAL4 bigenic system. Although ectopic Ihh does not induce overt ossification along the entire cartilage anlage, it promotes progression of the bone collar toward the epiphysis, suggesting a synergistic effect between ectopic Ihh and endogenous factors such as the bone morphogenetic proteins (BMPs). In keeping with this model, Hh signaling is further found to be required in BMP-induced osteogenesis in cultures of a limb-bud cell line. Taken together, these results demonstrate that Ihh signaling is directly required for the osteoblast lineage in the developing long bones and that Ihh functions in conjunction with other factors such as BMPs to induce osteoblast differentiation. We suggest that Ihh acts in vivo on a potential progenitor cell to promote osteoblast and prevent chondrocyte differentiation.

Asporin and transforming growth factor-beta gene expression in osteoblasts from subchondral bone and osteophytes in osteoarthritis.

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Sakao, Kei; Takahashi, Kenji A; Arai, Yuji; Saito, Masazumi; Honjyo, Kuniaki; Hiraoka, Nobuyuki; Kishida, Tsunao; Mazda, Osam; Imanishi, Jiro; Kubo, Toshikazu

2009-11-01

To clarify the significance of subchondral bone and osteophytes in the pathology of osteoarthritis (OA), we investigated the expression of asporin (ASPN), transforming growth factor-beta1 (TGF-beta1), TGF-beta2, TGF-beta3, and runt-related transcription factor-2 (Runx2) genes involved in bone metabolism. Osteoblasts were isolated from 19 patients diagnosed with knee OA and from 4 patients diagnosed with femoral neck fracture. Osteoblast expression of mRNA encoding ASPN, TGF-beta1, TGF-beta2, TGF-beta3, and Runx2 was analyzed using real-time RT-PCR. Expression of ASPN, TGF-beta1, and TGF-beta3 mRNA in the subchondral bone and osteophytes of OA patients increased compared with that of non-OA patients. The ratio of ASPN to TGF-beta1 mRNA in patients with severe cartilage damage was higher than that in patients with mild cartilage damage. The increased ratio of ASPN mRNA to TGF-beta1 mRNA in patients with severe relative to mild cartilage damage indicates that increased ASPN mRNA expression was significantly associated with the severity of cartilage degeneration. This finding suggests that ASPN may regulate TGF-beta1-mediated factors in the development of OA, which may provide clues as to the underlying pathology of OA.

Interaction of osteoblast-like cells with serum and fibronectin: effects on cell motility and proliferation in vitro

International Nuclear Information System (INIS)

Zuk, A.

1986-01-01

Osteoblast migration and proliferation are believed to occur during bone remodelling, in particular after osteoclastic bone resorption and prior to osteoblastic bone formation. In order to study migration and proliferation in vitro, the model of Alessandri et al. (1983) was modified. The model entailed seeding osteoblast-like cells into wells cut in agar and quantifying migration and proliferation peripheral to the well. Cell morphology also was described. The data indicated that on growth surfaces enriched with varying concentrations of fetal calf serum (FSC), the quantification of migration and proliferation was related both to percent cell attachment and to FCS-concentration. Because few osteoblast-like cells incorporated ( 3 H-TdR), it was concluded that the appearance of cells peripheral to the well was due to migration, and not to proliferation. Cell morphology and myosin distribution and organization indicated that osteoblast-like cells at the periphery of the cell culture (i.e. leading edge) may have been directionally migrating whereas cells behind the leading edge may have been engaged in non-directional migration. The migration, proliferation, and morphology of osteoblast-like cells cultured on fibronectin (FN) enriched growth surfaces also was examined. The quantification of migration and proliferation was related to the FN-concentration applied to the growth surface. Because few osteoblast-like cells incorporated 3 H-TdR and cell morphology indicated migration, it was concluded that osteoblast-like cells on FN-enriched growth surfaces are specialized, in part, for migration

Intracortical osteoblastic osteosarcoma with oncogenic rickets

International Nuclear Information System (INIS)

Hasegawa, T.; Hirohashi, Setsuo; Shimoda, Tadakazu; Yokoyama, Ryohei; Beppu, Yasuo; Maeda, Shotaro

1999-01-01

Intracortical osteosarcoma is the rarest variant of osteosarcoma, occurring within, and usually confined to, the cortical bone. Oncogenic osteomalacia, or rickets, is an unusual clinicopathologic entity in which vitamin D-resistant osteomalacia, or rickets, occurs in association with some tumors of soft tissue or bone. We present a case of oncogenic rickets associated with intracortical osteosarcoma of the tibia in a 9-year-old boy, whose roentgenographic abnormalities of rickets disappeared and pertinent laboratory data except for serum alkaline phosphatase became normal after surgical resection of the tumor. Histologically, the tumor was an osteosarcoma with a prominent osteoblastic pattern. An unusual microscopic feature was the presence of matrix mineralization showing rounded calcified structures (calcified spherules). Benign osteoblastic tumors, such as osteoid osteoma and osteoblastoma, must be considered in the differential diagnosis because of the relatively low cellular atypia and mitotic activity of this tumor. The infiltrating pattern with destruction or engulfment of normal bone is a major clue to the correct diagnosis of intracortical osteosarcoma. The co-existing radiographic changes of rickets were due to the intracortical osteosarcoma. (orig.)

Lysophosphatidic acid-functionalised titanium as a superior surface for supporting human osteoblast (MG63 maturation

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JP Mansell

2012-05-01

Full Text Available Covalent modifications of titanium with small molecules known to promote human osteoblast maturation are especially attractive in developing superior biomaterials. An important step in securing competent bone formation at implant sites is promoting the formation of mature osteoblasts, either from committed pre-osteoblasts or from their mesenchymal progenitors. To this end our research has focussed on identifying molecules that enhance human osteoblast formation and maturation and to develop ways of covalently attaching these molecules to implant surfaces so that they are more likely to withstand the rigors of the implantation process whilst still retaining their bioactivity. Herein we report the novel production of lipid-functionalised titanium using lysophosphatidic acid or a related compound, (3S 1-fluoro-3-hydroxy-4-butyl-1-phosphonate. Both lipids were especially effective at co-operating with calcitriol to promote human osteoblast maturation at these modified Ti surfaces in vitro. The novel findings presented offer enticing new developments towards the fabrication of next-generation implant devices with the potential to significantly enhance the osseointegration process and with it improvements in future prosthesis performance and longevity.

DNA–PKcs–SIN1 complexation mediates low-dose X-ray irradiation (LDI)-induced Akt activation and osteoblast differentiation

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Xu, Yong; Fang, Shi-ji [The Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou 215000 (China); Zhu, Li-juan [Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215021 (China); Zhu, Lun-qing, E-mail: xiaodongwangsz@163.com [The Center of Diagnosis and Treatment for Children’s Bone Diseases, The Children’s Hospital Affiliated to Soochow University, Suzhou, Jiangsu 215000 (China); Zhou, Xiao-zhong, E-mail: zhouxz@suda.edu.cn [The Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou 215000 (China)

2014-10-24

Highlights: • LDI increases ALP activity, promotes type I collagen (Col I)/Runx2 mRNA expression. • LDI induces DNA–PKcs activation, which is required for osteoblast differentiation. • Akt activation mediates LDI-induced ALP activity and Col I/Runx2 mRNA increase. • DNA–PKcs–SIN1 complexation mediates LDI-induced Akt Ser-473 phosphorylation. • DNA–PKcs–SIN1 complexation is important for osteoblast differentiation. - Abstract: Low-dose irradiation (LDI) induces osteoblast differentiation, however the underlying mechanisms are not fully understood. In this study, we explored the potential role of DNA-dependent protein kinase catalytic subunit (DNA–PKcs)–Akt signaling in LDI-induced osteoblast differentiation. We confirmed that LDI promoted mouse calvarial osteoblast differentiation, which was detected by increased alkaline phosphatase (ALP) activity as well as mRNA expression of type I collagen (Col I) and runt-related transcription factor 2 (Runx2). In mouse osteoblasts, LDI (1 Gy) induced phosphorylation of DNA–PKcs and Akt (mainly at Ser-473). The kinase inhibitors against DNA–PKcs (NU-7026 and NU-7441) or Akt (LY294002, perifosine and MK-2206), as well as partial depletion of DNA–PKcs or Akt1 by targeted-shRNA, dramatically inhibited LDI-induced Akt activation and mouse osteoblast differentiation. Further, siRNA-knockdown of SIN1, a key component of mTOR complex 2 (mTORC2), also inhibited LDI-induced Akt Ser-473 phosphorylation as well as ALP activity increase and Col I/Runx2 expression in mouse osteoblasts. Co-immunoprecipitation (Co-IP) assay results demonstrated that LDI-induced DNA–PKcs–SIN1 complexation, which was inhibited by NU-7441 or SIN1 siRNA-knockdown in mouse osteoblasts. In summary, our data suggest that DNA–PKcs–SIN1 complexation-mediated Akt activation (Ser-473 phosphorylation) is required for mouse osteoblast differentiation.

Nano hydroxyapatite-blasted titanium surface affects pre-osteoblast morphology by modulating critical intracellular pathways.

Science.gov (United States)

Bezerra, Fábio; Ferreira, Marcel R; Fontes, Giselle N; da Costa Fernandes, Célio Jr; Andia, Denise C; Cruz, Nilson C; da Silva, Rodrigo A; Zambuzzi, Willian F

2017-08-01

Although, intracellular signaling pathways are proposed to predict the quality of cell-surface relationship, this study addressed pre-osteoblast behavior in response to nano hydroxyapatite (HA)-blasted titanium (Ti) surface by exploring critical intracellular pathways and pre-osteoblast morphological change. Physicochemical properties were evaluated by atomic force microscopy (AFM) and wettability considering water contact angle of three differently texturized Ti surfaces: Machined (Mac), Dual acid-etching (DAE), and nano hydroxyapatite-blasted (nHA). The results revealed critical differences in surface topography, impacting the water contact angle and later the osteoblast performance. In order to evaluate the effect of those topographical characteristics on biological responses, we have seeded pre-osteoblast cells on the Ti discs for up to 4 h and subjected the cultures to biological analysis. First, we have observed pre-osteoblasts morphological changes resulting from the interaction with the Ti texturized surfaces whereas the cells cultured on nHA presented a more advanced spreading process when compared with the cells cultured on the other surfaces. These results argued us for analyzing the molecular machinery and thus, we have shown that nHA promoted a lower Bax/Bcl2 ratio, suggesting an interesting anti-apoptotic effect, maybe explained by the fact that HA is a natural element present in bone composition. Thereafter, we investigated the potential effect of those surfaces on promoting pre-osteoblast adhesion and survival signaling by performing crystal violet and immunoblotting approaches, respectively. Our results showed that nHA promoted a higher pre-osteoblast adhesion supported by up-modulating FAK and Src activations, both signaling transducers involved during eukaryotic cell adhesion. Also, we have shown Ras-Erk stimulation by the all evaluated surfaces. Finally, we showed that all Ti-texturing surfaces were able to promote osteoblast differentiation

The aryl hydrocarbon receptor suppresses osteoblast proliferation and differentiation through the activation of the ERK signaling pathway

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Yu, Haitao; Du, Yuxuan; Zhang, Xulong; Sun, Ying; Li, Shentao; Dou, Yunpeng [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Li, Zhanguo [Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People' s Hospital, No. 11 Xizhimen South Street, Beijing 100044 (China); Yuan, Huihui, E-mail: huihui_yuan@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Zhao, Wenming, E-mail: zhao-wenming@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China)

2014-11-01

Ahr activation is known to be associated with synovitis and exacerbated rheumatoid arthritis (RA), but its contributions to bone loss have not been completely elucidated. Osteoblast proliferation and differentiation are abnormal at the erosion site in RA. Here, we reported that the expression of Ahr was increased in the hind paws' bone upon collagen-induced arthritis (CIA) in mice, and the levels of Ahr were negatively correlated with bone mineral density (BMD). In addition, immunofluorescent staining showed that the high expression of Ahr was mainly localized in osteoblasts from the CIA mice compared to normal controls. Moreover, the luciferase intensity of Ahr in the nucleus increased by 12.5% in CIA osteoblasts compared to that in normal controls. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) activation of the Ahr inhibited pre-osteoblast MC3T3-E1 cellular proliferation and differentiation in a dose-dependent manner. Interestingly, the levels of alkaline phosphatase (ALP) mRNA expression in the osteoblasts of CIA mice were reduced compared to normal controls. In contrast, decreased ALP expression by activated Ahr was completely reversed after pretreatment with an Ahr inhibitor (CH-223191) in MC3T3-E1 cell lines and primary osteoblasts on day 5. Our data further showed that activation of Ahr promoted the phosphorylation of ERK after 5 days. Moreover, Ahr-dependent activation of the ERK signaling pathway decreased the levels of proliferation cells and inhibited ALP activity in MC3T3-E1 cells. These results demonstrated that the high expression of Ahr may suppress osteoblast proliferation and differentiation through activation of the ERK signaling pathway, further enabling bone erosion in CIA mice. - Highlights: • The upregulation of Ahr was localized in osteoblasts of CIA mice. • The overexpression of Ahr suppressed osteoblast development. • The Ahr activated ERK signaling pathway to exacerbate bone erosion.

Generation of Directly Converted Human Osteoblasts That Are Free of Exogenous Gene and Xenogenic Protein.

Science.gov (United States)

Yamamoto, Kenta; Sato, Yoshiki; Honjo, Kenichi; Ichioka, Hiroaki; Oseko, Fumishige; Sowa, Yoshihiro; Yamamoto, Toshiro; Kanamura, Narisato; Kishida, Tsunao; Mazda, Osam

2016-11-01

Generation of osteoblasts from human somatic cells may be applicable in an effective transplantation therapy against bone diseases. Recently we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some transcription factor genes via retroviral vectors. However, retroviral vector-mediated transduction may potentially cause tumor formation from the infected cells, thus a non-viral gene transfection method may be more preferable for preparation of osteoblasts to be used for transplantation therapy. Here, we constructed a plasmid vector encoding Oct4, Osterix, and L-Myc that were an appropriate combination of transcription factors for this purpose. Osteoblast-like phenotypes including high alkaline phosphatase (ALP) activity, bone matrix production and osteoblast-specific gene expression were induced in normal human fibroblasts that were transfected with the plasmid followed by culturing in osteogenic medium. The plasmid-driven directly converted osteoblasts (p-dOBs) were obtained even in the absence of a xenogenic protein. The plasmid vector sequence had fallen out of the p-dOBs. The cells formed deposition of calcified bodies in situ after transplantation into mice. These results strongly suggest that p-dOBs can be put into practical use for a novel cell-based therapy against bone diseases. J. Cell. Biochem. 117: 2538-2545, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Lactoferrin promote primary rat osteoblast proliferation and differentiation via up-regulation of insulin-like growth factor-1 expression.

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Hou, Jian-ming; Wu, Man; Lin, Qing-ming; Lin, Fan; Xue, Ying; Lan, Xu-hua; Chen, En-yu; Wang, Mei-li; Yang, Hai-yan; Wang, Feng-xiong

2014-08-01

The aim of this study was to explore the effect of lactoferrin (LF) in primary fetal rat osteoblasts proliferation and differentiation and investigate the underlying molecular mechanisms. Primary rat osteoblasts were obtained from the calvarias of neonatal rats. Osteoblasts were treated with LF (0.1-1000 μg/mL), or OSI-906 [a selective inhibitor of insulin-like growth factor 1 (IGF-1) receptor and insulin receptor]. The IGF-1 was then knocked down by small hairpin RNA (shRNA) technology and then was treated with recombinant human IGF-1 or LF. Cell proliferation and differentiation were measured by MTT assay and alkaline phosphatase (ALP) assay, respectively. The expression of IGF-1 and IGF binding protein 2 (IGFBP2) mRNA were analyzed using real-time PCR. LF promotes the proliferation and differentiation of osteoblasts in a certain range (1-100 μg/mL) in time- and dose-dependent manner. The mRNA level of IGF-1 was significantly increased, while the expression of IGFBP2 was suppressed by LF treatment. Knockdown of IGF-1 by shRNA in primary rat osteoblast dramatically decreased the abilities of proliferation and differentiation of osteoblasts and blocked the proliferation and differentiation effect of LF in osteoblasts. OSI906 (5 μM) blocked the mitogenic and differentiation of LF in osteoblasts. Proliferation and differentiation of primary rat osteoblasts in response to LF are mediated in part by stimulating of IGF-1 gene expression and alterations in the gene expression of IGFBP2.

Human immunodeficiency virus envelope protein Gp120 induces proliferation but not apoptosis in osteoblasts at physiologic concentrations.

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Nathan W Cummins

Full Text Available Patients with HIV infection have decreased numbers of osteoblasts, decreased bone mineral density and increased risk of fracture compared to uninfected patients; however, the molecular mechanisms behind these associations remain unclear. We questioned whether Gp120, a component of the envelope protein of HIV capable of inducing apoptosis in many cell types, is able to induce cell death in bone-forming osteoblasts. We show that treatment of immortalized osteoblast-like cells and primary human osteoblasts with exogenous Gp120 in vitro at physiologic concentrations does not result in apoptosis. Instead, in the osteoblast-like U2OS cell line, cells expressing CXCR4, a receptor for Gp120, had increased proliferation when treated with Gp120 compared to control (P<0.05, which was inhibited by pretreatment with a CXCR4 inhibitor and a G-protein inhibitor. This suggests that Gp120 is not an inducer of apoptosis in human osteoblasts and likely does not directly contribute to osteoporosis in infected patients by this mechanism.

Bioactive treatment promotes osteoblast differentiation on titanium materials fabricated by selective laser melting technology.

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Tsukanaka, Masako; Fujibayashi, Shunsuke; Takemoto, Mitsuru; Matsushita, Tomiharu; Kokubo, Tadashi; Nakamura, Takashi; Sasaki, Kiyoyuki; Matsuda, Shuichi

2016-01-01

Selective laser melting (SLM) technology is useful for the fabrication of porous titanium implants with complex shapes and structures. The materials fabricated by SLM characteristically have a very rough surface (average surface roughness, Ra=24.58 µm). In this study, we evaluated morphologically and biochemically the specific effects of this very rough surface and the additional effects of a bioactive treatment on osteoblast proliferation and differentiation. Flat-rolled titanium materials (Ra=1.02 µm) were used as the controls. On the treated materials fabricated by SLM, we observed enhanced osteoblast differentiation compared with the flat-rolled materials and the untreated materials fabricated by SLM. No significant differences were observed between the flat-rolled materials and the untreated materials fabricated by SLM in their effects on osteoblast differentiation. We concluded that the very rough surface fabricated by SLM had to undergo a bioactive treatment to obtain a positive effect on osteoblast differentiation.

Slight changes in the mechanical stimulation affects osteoblast- and osteoclast-like cells in co-culture.

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Kadow-Romacker, Anke; Duda, Georg N; Bormann, Nicole; Schmidmaier, Gerhard; Wildemann, Britt

2013-12-01

Osteoblast- and osteoclast-like cells are responsible for coordinated bone maintenance, illustrated by a balanced formation and resorption. Both parameters appear to be influenced by mechanical constrains acting on each of these cell types individually. We hypothesized that the interactions between both cell types are also influenced by mechanical stimulation. Co-cultures of osteoblast- and osteoclast-like cells were stimulated with 1,100 µstrain, 0.1 or 0.3 Hz for 1-5 min/day over 5 days. Two different setups depending on the differentiation of the osteoclast-like cells were used: i) differentiation assay for the fusion of pre-osteoclasts to osteoclasts, ii) resorption assay to determine the activity level of osteoclast-like cells. In the differentiation assay (co-culture of osteoblasts with unfused osteoclast precursor cells) the mechanical stimulation resulted in a significant decrease of collagen-1 and osteocalcin produced by osteoblast-like cells. Significantly more TRAP-iso5b was measured after stimulation for 3 min with 0.1 Hz, indicating enhanced osteoclastogenesis. In the resorption assay (co-culture of osteoblasts with fused osteoclasts) the stimulation for 3 min with 0.3 Hz significantly increased the resorption activity of osteoclasts measured by the pit formation and the collagen resorption. The same mechanical stimulation resulted in an increased collagen-1 production by the osteoblast-like cells. The ratio of RANKL/OPG was not different between the groups. These findings demonstrate that already small changes in duration or frequency of mechanical stimulation had significant consequences for the behavior of osteoblast- and osteoclast-like cells in co-culture, which partially depend on the differentiation status of the osteoclast-like cells.

Influences of magnetized hydroxyapatite on the growth behaviors of osteoblasts and the mechanism from molecular dynamics simulation

International Nuclear Information System (INIS)

Yang, Weihu; Xi, Xingfeng; Fang, Jiajia; Liu, Peng; Cai, Kaiyong

2013-01-01

To investigate the influence of magnetized hydroxyapatite on the growth and differentiation of osteoblasts, hydroxyapatite (HA) and magnetized hydroxyapatite (mHA) were synthesized and characterized. The cell viability, differentiation, and morphologies of osteoblasts were investigated in vitro, respectively. The results showed that compared to HA, cells cultured with mHA had better cell viability, and both HA and mHA were beneficial to the early differentiation of osteoblasts. Furthermore, the interaction mechanism between mHA and osteoblasts was elucidated using a molecular dynamics simulation. The simulation results indicated that when cultured with osteoblasts, HA adsorbed bovine serum protein onto its surface from the medium immediately, which was beneficial to the adhesion and proliferation of osteoblasts. The main driving force for the adsorption of bovine serum was the electronic properties of HA crystal faces. The (211) crystal face of HA had the highest electron density among its all crystal faces, thus mainly contributing to the protein adsorption of HA. Nevertheless, the (211) crystal face of mHA still had a relatively higher electron density than that of HA, thus possessing better protein adsorption than that of HA, and in turn promoting the biological functions of osteoblasts. - Highlights: • Both HA and magnetized HA were beneficial for the early osteogenesis of osteoblasts. • Magnetized HA had better cell viability than HA. • The HA–protein interaction mechanism was investigated by computation simulation. • The main driving force for protein adsorption came from the electronic properties. • The (211) face of mHA has higher electron density and better biological functions

Involvement of the G-protein-coupled receptor 4 in RANKL expression by osteoblasts in an acidic environment

Energy Technology Data Exchange (ETDEWEB)

Okito, Asuka [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan); Department of Orthodontic Science, Tokyo Medical and Dental University, Tokyo (Japan); Nakahama, Ken-ichi, E-mail: nakacell@tmd.ac.jp [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan); Akiyama, Masako [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan); Ono, Takashi [Department of Orthodontic Science, Tokyo Medical and Dental University, Tokyo (Japan); Morita, Ikuo [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan)

2015-03-06

Osteoclast activity is enhanced in acidic environments following systemic or local inflammation. However, the regulatory mechanism of receptor activator of NF-κB ligand (RANKL) expression in osteoblasts under acidic conditions is not fully understood. In the present paper, we detected the mRNA expression of the G-protein-coupled receptor (GPR) proton sensors GPR4 and GPR65 (T-cell death-associated gene 8, TDAG8), in osteoblasts. RANKL expression and the cyclic AMP (cAMP) level in osteoblasts were up-regulated under acidic culture conditions. Acidosis-induced up-regulation of RANKL was abolished by the protein kinase A inhibitor H89. To clarify the role of GPR4 in RANKL expression, GPR4 gain and loss of function experiments were performed. Gene knockdown and forced expression of GPR4 caused reduction and induction of RANKL expression, respectively. These results suggested that, at least in part, RANKL expression by osteoblasts in an acidic environment was mediated by cAMP/PKA signaling resulting from GPR4 activation. A comprehensive microarray analysis of gene expression of osteoblasts revealed that, under acidic conditions, the phenotype of osteoblasts was that of an osteoclast supporting cell rather than that of a mineralizing cell. These findings will contribute to a molecular understanding of bone disruption in an acidic environment. - Highlights: • RANKL expression was increased in osteoblasts under acidosis via cAMP/PKA pathway. • GRP4 knockdown resulted in decrease of RANKL expression. • GRP4 overexpression resulted in increase of RANKL expression. • Osteoblast mineralization was reduced under acidic condition.

Potential of Resveratrol Analogues as Antagonists of Osteoclasts and Promoters of Osteoblasts

DEFF Research Database (Denmark)

Kupisiewicz, Katarzyna; Boissy, Patrice; Abdallah, Basem M

2010-01-01

The plant phytoalexin resveratrol was previously demonstrated to inhibit the differentiation and bone resorbing activity of osteoclasts, to promote the formation of osteoblasts from mesenchymal precursors in cultures, and inhibit myeloma cell proliferation, when used at high concentrations....... In the current study, we screened five structurally modified resveratrol analogues for their ability to modify the differentiation of osteoclasts and osteoblasts and proliferation of myeloma cells. Compared to resveratrol, analogues showed an up to 5,000-fold increased potency to inhibit osteoclast...... differentiation. To a lesser extent, resveratrol analogues also promoted osteoblast maturation. However, they did not antagonize the proliferation of myeloma cells. The potency of the best-performing candidate in vitro was tested in vivo in an ovariectomy-induced model of osteoporosis, but an effect on bone loss...

Does collagen trigger the recruitment of osteoblasts into vacated bone resorption lacunae during bone remodeling?

DEFF Research Database (Denmark)

Abdelgawad, Mohamed Essameldin; Søe, Kent; Andersen, Thomas Levin

2014-01-01

matrix molecules, collagen's potency was superior and only equaled by fibronectin. Next, the majority of the newly recruited osteoblast lineage cells positioned immediately next to the osteoclasts exhibit uPARAP/Endo180, an endocytic collagen receptor reported to be involved in collagen internalization......Osteoblast recruitment during bone remodeling is obligatory to re-construct the bone resorbed by the osteoclast. This recruitment is believed to be triggered by osteoclast products and is therefore likely to start early during the remodeling cycle. Several osteoclast products with osteoblast...... recruitment potential are already known. Here we draw the attention on the osteoblast recruitment potential of the collagen that is freshly demineralized by the osteoclast. Our evidence is based on observations on adult human cancellous bone, combined with in vitro assays. First, freshly eroded surfaces where...

Effects of platelet rich plasma (PRP) on human gingival fibroblast, osteoblast and periodontal ligament cell behaviour.

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Kobayashi, Eizaburo; Fujioka-Kobayashi, Masako; Sculean, Anton; Chappuis, Vivianne; Buser, Daniel; Schaller, Benoit; Dőri, Ferenc; Miron, Richard J

2017-06-02

The use of platelet rich plasma (PRP, GLO) has been used as an adjunct to various regenerative dental procedures. The aim of the present study was to characterize the influence of PRP on human gingival fibroblasts, periodontal ligament (PDL) cells and osteoblast cell behavior in vitro. Human gingival fibroblasts, PDL cells and osteoblasts were cultured with conditioned media from PRP and investigated for cell migration, proliferation and collagen1 (COL1) immunostaining. Furthermore, gingival fibroblasts were tested for genes encoding TGF-β, PDGF and COL1a whereas PDL cells and osteoblasts were additionally tested for alkaline phosphatase (ALP) activity, alizarin red staining and mRNA levels of osteoblast differentiation markers including Runx2, COL1a2, ALP and osteocalcin (OCN). It was first found that PRP significantly increased cell migration of all cells up to 4 fold. Furthermore, PRP increased cell proliferation at 3 and 5 days of gingival fibroblasts, and at 3 days for PDL cells, whereas no effect was observed on osteoblasts. Gingival fibroblasts cultured with PRP increased TGF-β, PDGF-B and COL1 mRNA levels at 7 days and further increased over 3-fold COL1 staining at 14 days. PDL cells cultured with PRP increased Runx2 mRNA levels but significantly down-regulated OCN mRNA levels at 3 days. No differences in COL1 staining or ALP staining were observed in PDL cells. Furthermore, PRP decreased mineralization of PDL cells at 14 days post seeding as assessed by alizarin red staining. In osteoblasts, PRP increased COL1 staining at 14 days, increased COL1 and ALP at 3 days, as well as increased ALP staining at 14 days. No significant differences were observed for alizarin red staining of osteoblasts following culture with PRP. The results demonstrate that PRP promoted gingival fibroblast migration, proliferation and mRNA expression of pro-wound healing molecules. While PRP induced PDL cells and osteoblast migration and proliferation, it tended to have

In vitro studies of osteoblasts response onto zinc aluminate ceramic films

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Marco Antonio Alvarez-Pérez

2009-01-01

Full Text Available Zinc based or doped ceramics have shown to be capable of increasing osteoblasts proliferation, biomineralization and bone formation. However, studies regarding the biological applications processes in ZnAl2O4 ceramic films are very scarce. For this reason, the objective of this in vitro study was to investigate the response of osteoblasts cells cultured onto ZnAl2O4 films. Our results showed a good biological response related to attachment and viability, with good cell morphology attached to the semi-spherical grains of the ceramic and the analysis of mineral-like tissue showed a high quantity of mineral deposited and organized as tiny spherical-like nodules attached to nanostructure surface of ZnAl2O4 material films. Based in our results, ZnAl2O4 films stimulated the bioactivity of osteoblasts cells and provide a microenvironment that favors cell differentiation and mineralization processes, suggesting their potential use as osteoconductive coating onto currently orthopedic and dental implants.

Conditional deletion of Hdac3 in osteoprogenitor cells attenuates diet-induced systemic metabolic dysfunction

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McGee-Lawrence, Meghan E.; White, Thomas A.; LeBrasseur, Nathan K.; Westendorf, Jennifer J.

2015-01-01

Obesity is a major health epidemic in the United States and a leading cause of preventable diseases including type 2 diabetes. A growing body of evidence indicates that the skeleton influences whole body metabolism and suggests a new avenue for developing novel therapeutic agents, but the underlying mechanisms are not well understood. Here, it is demonstrated that conditional deletion of an epigenetic regulator, Hdac3, in osteoblast progenitor cells abrogates high fat diet-induced insulin resistance and hepatic steatosis. These Hdac3-deficient mice have reduced bone formation and lower circulating levels of total and undercarboxylated osteocalcin, coupled with decreased bone resorption activity. They also maintain lower body fat and fasting glucose levels on normal and high fat chow diets. The mechanisms by which Hdac3 controls systemic energy homeostasis from within osteoblasts have not yet been fully realized, but the current study suggests that it does not involve elevated levels of circulating osteocalcin. Thus, Hdac3 is a new player in the emerging paradigm that the skeleton influences systemic energy metabolism. PMID:25666992

Knockdown of Indian hedgehog protein induces an inhibition of cell growth and differentiation in osteoblast MC3T3-E1 cells

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Deng, Ang; Zhang, Hongqi; Hu, Minyu; Liu, Shaohua; Gao, Qile; Wang, Yuxiang; Guo, Chaofeng

2017-01-01

Indian hedgehog protein (Ihh) is evolutionarily conserved and serves important roles in controlling the differentiation of progenitor cells into osteoblasts. Ihh null mutant mice exhibit a failure of osteoblast development in endochondral bone. Although studies have demonstrated that Ihh signaling is a potent local factor that regulates osteoblast differentiation, the specific transcription factors that determine osteoblast differentiation remain unclear. Further studies are required to determine the precise mechanism through which Ihh regulates osteoblast differentiation. In the present study, Ihh was knocked down in osteoblast MC3T3-E1 cells using short hairpin RNA, to investigate the function of Ihh in osteoblast proliferation and differentiation and to examine the potential mechanism through which Ihh induces osteoblast apoptosis and cell cycle arrest. It was observed that the knockdown of Ihh induced a marked inhibition of cell growth and increased the apoptosis rate compared with the negative control osteoblasts. Downregulation of Ihh resulted in a cell cycle arrest at the G1 to S phase boundary in osteoblasts. In addition, the knockdown of Ihh decreased the alkaline phosphatase activity and mineral deposition of osteoblasts. The inhibitory roles of Ihh downregulation in osteoblast growth and differentiation may be associated with the transforming growth factor-β/mothers against decapentaplegic homolog and tumor necrosis factor receptor superfamily member 11B/tumor necrosis factor ligand superfamily member 11 signaling pathways. Manipulating either Ihh expression or its signaling components may be of benefit for the treatment of skeletal diseases. PMID:28990069

Microcracks induce osteoblast alignment and maturation on hydroxyapatite scaffolds

Science.gov (United States)

Shu, Yutian

Physiological bone tissue is a mineral/collagen composite with a hierarchical structure. The features in bone, such as mineral crystals, fibers, and pores can range from the nanometer to the centimeter in size. Currently available bone tissue scaffolds primarily address the chemical composition, pore size, and pore size distribution. While these design parameters are extensively investigated for mimicking bone function and inducing bone regeneration, little is known about microcracks, which is a prevalent feature found in fractured bone in vivo and associated with fracture healing and repair. Since the purpose of bone tissue engineering scaffold is to enhance bone regeneration, the coincidence of microcracks and bone densification should not be neglected but rather be considered as a potential parameter in bone tissue engineering scaffold design. The purpose of this study is to test the hypothesis that microcracks enhance bone healing. In vitro studies were designed to investigate the osteoblast (bone forming cells) response to microcracks in dense (94%) hydroxyapatite substrates. Microcracks were introduced using a well-established Vickers indentation technique. The results of our study showed that microcracks induced osteoblast alignment, enhanced osteoblast attachment and more rapid maturation. These findings may provide insight into fracture healing mechanism(s) as well as improve the design of bone tissue engineering orthopedic scaffolds for more rapid bone regeneration.

Cytokine expression in human osteoblasts after antiseptic treatment: a comparative study between polyhexanide and chlorhexidine.

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Röhner, Eric; Hoff, Paula; Gaber, Timo; Lang, Annemarie; Vörös, Pauline; Buttgereit, Frank; Perka, Carsten; Windisch, Christoph; Matziolis, Georg

2015-02-01

Chlorhexidine and polyhexanide are frequently used antiseptics in clinical practice and have a broad antimicrobial range. Both antiseptics are helpful medical agents for septic wound treatment with a high potential for defeating joint infections. Their effect on human osteoblasts has, so far, not been sufficiently evaluated. The aim of this study was to investigate the activating potential of polyhexanide and chlorhexidine on inflammatory cytokines/chemokines in human osteoblasts in vitro. Human osteoblasts were isolated and cultivated in vitro and then treated separately with 0.1% and 2% chlorhexidine and 0.04% polyhexanide as commonly applied concentrations in clinical practice. Detection of cell structure and cell morphology was performed by light microscopic inspection. Cytokine and chemokine secretion was determined by using a multiplex suspension array. Cell shrinking, defective cell membrane, and the loss of cell adhesion indicated cell damage of human osteoblasts after treatment with both antiseptics was evaluated by using light microscopy. Polyhexanide, but not chlorhexidine, caused human osteoblasts to secrete various interleukins (1β, 6, and 7), interferon γ, tumor necrosis factor α, vascular endothelial growth factor, eotaxin, fibroblast growth factor basic, and granulocyte macrophage colony-stimulating factor as quantified by multiplex suspension array. Both antiseptics induced morphological cell damage at an optimum exposure between 1 and 10 min. But only polyhexanide mediated a pronounced secretion of inflammatory cytokines and chemokines in human osteoblasts. Therefore, we recommend a preferred usage of chlorhexidine in septic surgery to avoid the induction of an inflammatory reaction.

Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

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Zhang Lingli; Fan Hongsong; Zhang Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, Sichuan 610064 (China); Hanagata, Nobutaka; Ikoma, Toshiyuki [Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Maeda, Megumi; Minowa, Takashi, E-mail: HANAGATA.Nobutaka@nims.go.j [Nanotechnology Innovation Center, National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan)

2009-04-15

Because calcium phosphate (Ca-P) ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca-P ceramics with different Ca-P ratios, i.e. hydroxyapatite (HA), beta-tricalcium phosphate ({beta}-TCP), and biphasic calcium phosphate (BCP) ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca-P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca-P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker) in tissue grown in pores was also higher in hydroxyapatite and BCP than in {beta}-TCP. In the pores of any Ca-P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca-P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than {beta}-TCP.

Pulsed electromagnetic fields promote the proliferation and differentiation of osteoblasts by reinforcing intracellular calcium transients.

Science.gov (United States)

Tong, Jie; Sun, Lijun; Zhu, Bin; Fan, Yun; Ma, Xingfeng; Yu, Liyin; Zhang, Jianbao

2017-10-01

Pulsed electromagnetic fields (PEMF) can be used to treat bone-related diseases, but the underlying mechanism remains unclear, especially the process by which PEMFs initiate biological effects. In this study, we demonstrated the effects of PEMF on proliferation and differentiation of osteoblasts using the model of calcium transients induced by high extracellular calcium. Our results showed that PEMF can increase both the percentage of responding cells and amplitude of intracellular calcium transients induced by high extracellular calcium stimulation. Compared with corresponding extracellular calcium levels, PEMF stimulation increased proliferation and differentiation of osteoblasts and related gene expressions, such as insulin-like growth factor 1 (IGF-1), alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), which can be completely abolished by BAPTA-AM. Moreover, PEMF did not affect proliferation and differentiation of osteoblasts if no intracellular calcium transient was present in osteoblasts during PEMF exposure. Our results revealed that PEMF affects osteoblast proliferation and differentiation through enhanced intracellular calcium transients, which provided a cue to treat bone-related diseases with PEMF. Bioelectromagnetics. 38:541-549, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

LIF inhibits osteoblast differentiation at least in part by regulation of HAS2 and its product hyaluronan.

Science.gov (United States)

Falconi, Dominic; Aubin, Jane E

2007-08-01

LIF arrests osteogenesis in fetal rat calvaria cells in a differentiation stage-specific manner. Differential display identified HAS2 as a LIF-induced gene and its product, HA, modulated osteoblast differentiation similarly to LIF. Our data suggest that LIF arrests osteoblast differentiation by altering HA content of the extracellular matrix. Leukemia inhibitory factor (LIF) elicits both anabolic and catabolic effects on bone. We previously showed in the fetal rat calvaria (RC) cell system that LIF inhibits osteoblast differentiation at the late osteoprogenitor/early osteoblast stage. To uncover potential molecular mediators of this inhibitory activity, we used a positive-negative genome-wide differential display screen to identify LIF-induced changes in the developing osteoblast transcriptome. Although LIF signaling is active throughout the RC cell proliferation-differentiation sequence, only a relatively small number of genes, in several different functional clusters, are modulated by LIF specifically during the LIF-sensitive inhibitory time window. Based on their known and predicted functions, most of the LIF-regulated genes identified are plausible candidates to be involved in the LIF-induced arrest of osteoprogenitor differentiation. To test this hypothesis, we further analyzed the function of one of the genes identified, hyaluronan synthase 2 (HAS2), in the LIF-induced inhibition. Synthesis of hyaluronan (HA), the product of HAS enzymatic activity, was stimulated by LIF and mimicked the HAS2 expression profile, with highest expression in early/proliferative and late/maturing cultures and lowest levels in intermediate/late osteoprogenitor-early osteoblast cultures. Exogenously added high molecular weight HA, the product of HAS2, dose-dependently inhibited osteoblast differentiation, with pulse-treatment effective in the same differentiation stage-specific inhibitory window as seen with LIF. In addition, however, pulse treatment with HA in early cultures

Measurement of oxygen consumption rate of osteoblasts from ...

African Journals Online (AJOL)

Jane

2011-05-10

May 10, 2011 ... E-mail: kedongsong@dlut.edu.cn. Tel: +86 411 ... the experiments, including inverted phase contrast microscope. (IX70-Olympus ... The pictures showed that the osteoblasts still had very high cellular viability. consumption of ...

Engraftment Outcomes after HPC Co-Culture with Mesenchymal Stromal Cells and Osteoblasts

Directory of Open Access Journals (Sweden)

Matthew M. Cook

2013-09-01

Full Text Available Haematopoietic stem cell (HSC transplantation is an established cell-based therapy for a number of haematological diseases. To enhance this therapy, there is considerable interest in expanding HSCs in artificial niches prior to transplantation. This study compared murine HSC expansion supported through co-culture on monolayers of either undifferentiated mesenchymal stromal cells (MSCs or osteoblasts. Sorted Lineage− Sca-1+ c-kit+ (LSK haematopoietic stem/progenitor cells (HPC demonstrated proliferative capacity on both stromal monolayers with the greatest expansion of LSK shown in cultures supported by osteoblast monolayers. After transplantation, both types of bulk-expanded cultures were capable of engrafting and repopulating lethally irradiated primary and secondary murine recipients. LSKs co-cultured on MSCs showed comparable, but not superior, reconstitution ability to that of freshly isolated LSKs. Surprisingly, however, osteoblast co-cultured LSKs showed significantly poorer haematopoietic reconstitution compared to LSKs co-cultured on MSCs, likely due to a delay in short-term reconstitution. We demonstrated that stromal monolayers can be used to maintain, but not expand, functional HSCs without a need for additional haematopoietic growth factors. We also demonstrated that despite apparently superior in vitro performance, co-injection of bulk cultures of osteoblasts and LSKs in vivo was detrimental to recipient survival and should be avoided in translation to clinical practice.

Activation of L-type calcium channels is required for gap junction-mediated intercellular calcium signaling in osteoblastic cells

DEFF Research Database (Denmark)

Jørgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne

2003-01-01

The propagation of mechanically induced intercellular calcium waves (ICW) among osteoblastic cells occurs both by activation of P2Y (purinergic) receptors by extracellular nucleotides, resulting in "fast" ICW, and by gap junctional communication in cells that express connexin43 (Cx43), resulting...... in "slow" ICW. Human osteoblastic cells transmit intercellular calcium signals by both of these mechanisms. In the current studies we have examined the mechanism of slow gap junction-dependent ICW in osteoblastic cells. In ROS rat osteoblastic cells, gap junction-dependent ICW were inhibited by removal...... of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx...

Skeletal (stromal) stem cells: an update on intracellular signaling pathways controlling osteoblast differentiation.

Science.gov (United States)

Abdallah, Basem M; Jafari, Abbas; Zaher, Walid; Qiu, Weimin; Kassem, Moustapha

2015-01-01

Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy for identifying druggable targets for enhancing bone formation. This review will discuss the functions and the molecular mechanisms of action on osteoblast differentiation and bone formation; of a number of recently identified regulatory molecules: the non-canonical Notch signaling molecule Delta-like 1/preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of metabolic and respiratory acidosis on intracellular calcium in osteoblasts.

Science.gov (United States)

Frick, Kevin K; Bushinsky, David A

2010-08-01

In vivo, metabolic acidosis {decreased pH from decreased bicarbonate concentration ([HCO(3)(-)])} increases urine calcium (Ca) without increased intestinal Ca absorption, resulting in a loss of bone Ca. Conversely, respiratory acidosis [decreased pH from increased partial pressure of carbon dioxide (Pco(2))] does not appreciably alter Ca homeostasis. In cultured bone, chronic metabolic acidosis (Met) significantly increases cell-mediated net Ca efflux while isohydric respiratory acidosis (Resp) does not. The proton receptor, OGR1, appears critical for cell-mediated, metabolic acid-induced bone resorption. Perfusion of primary bone cells or OGR1-transfected Chinese hamster ovary (CHO) cells with Met induces transient peaks of intracellular Ca (Ca(i)). To determine whether Resp increases Ca(i), as does Met, we imaged Ca(i) in primary cultures of bone cells. pH for Met = 7.07 ([HCO(3)(-)] = 11.8 mM) and for Resp = 7.13 (Pco(2) = 88.4 mmHg) were similar and lower than neutral (7.41). Both Met and Resp induced a marked, transient increase in Ca(i) in individual bone cells; however, Met stimulated Ca(i) to a greater extent than Resp. We used OGR1-transfected CHO cells to determine whether OGR1 was responsible for the greater increase in Ca(i) in Met than Resp. Both Met and Resp induced a marked, transient increase in Ca(i) in OGR1-transfected CHO cells; however, in these cells Met was not different than Resp. Thus, the greater induction of Ca(i) by Met in primary bone cells is not a function of OGR1 alone, but must involve H(+) receptors other than OGR1, or pathways sensitive to Pco(2), HCO(3)(-), or total CO(2) that modify the effect of H(+) in primary bone cells.

The effects of 6-gingerol on proliferation, differentiation, and maturation of osteoblast-like MG-63 cells

Energy Technology Data Exchange (ETDEWEB)

Fan, J.Z.; Yang, X.; Bi, Z.G. [Department of Orthopedic Surgery, First Affiliated Hospital, Harbin Medicine University, Harbin (China)

2015-04-28

We investigated whether 6-gingerol affects the maturation and proliferation of osteoblast-like MG63 cells in vitro. Osteoblast-like MG63 cells were treated with 6-gingerol under control conditions, and experimental inflammation was induced by tumor necrosis factor-α (TNF-α). Expression of different osteogenic markers and cytokines was analyzed by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay. In addition, alkaline phosphatase (ALP) enzyme activity and biomineralization as markers for differentiation were measured. Treatment with 6-gingerol resulted in insignificant effects on the proliferation rate. 6-Gingerol induced the differentiation of osteoblast-like cells with increased transcription levels of osteogenic markers, upregulated ALP enzyme activity, and enhanced mineralized nodule formation. Stimulation with TNF-α led to enhanced interleukin-6 and nuclear factor-κB expression and downregulated markers of osteoblastic differentiation. 6-Gingerol reduced the degree of inflammation in TNF-α-treated MG-63 cells. In conclusion, 6-gingerol stimulated osteoblast differentiation in normal physiological and inflammatory settings, and therefore, 6-gingerol represents a promising agent for treating osteoporosis or bone inflammation.

Intracortical osteoblastic osteosarcoma with oncogenic rickets

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, T.; Hirohashi, Setsuo [Pathology Division, National Cancer Center Research Institute, Tokyo (Japan); Shimoda, Tadakazu [Clinical Laboratory Division, National Cancer Center Hospital, Tokyo (Japan); Yokoyama, Ryohei; Beppu, Yasuo [Orthopedic Division, National Cancer Center Hospital, Tokyo (Japan); Maeda, Shotaro [Department of Pathology, Nippon Medical School Hospital, Tokyo (Japan)

1999-01-01

Intracortical osteosarcoma is the rarest variant of osteosarcoma, occurring within, and usually confined to, the cortical bone. Oncogenic osteomalacia, or rickets, is an unusual clinicopathologic entity in which vitamin D-resistant osteomalacia, or rickets, occurs in association with some tumors of soft tissue or bone. We present a case of oncogenic rickets associated with intracortical osteosarcoma of the tibia in a 9-year-old boy, whose roentgenographic abnormalities of rickets disappeared and pertinent laboratory data except for serum alkaline phosphatase became normal after surgical resection of the tumor. Histologically, the tumor was an osteosarcoma with a prominent osteoblastic pattern. An unusual microscopic feature was the presence of matrix mineralization showing rounded calcified structures (calcified spherules). Benign osteoblastic tumors, such as osteoid osteoma and osteoblastoma, must be considered in the differential diagnosis because of the relatively low cellular atypia and mitotic activity of this tumor. The infiltrating pattern with destruction or engulfment of normal bone is a major clue to the correct diagnosis of intracortical osteosarcoma. The co-existing radiographic changes of rickets were due to the intracortical osteosarcoma. (orig.) With 8 figs., 25 refs.

Bmp2 in osteoblasts of periosteum and trabecular bone links bone formation to vascularization and mesenchymal stem cells

Science.gov (United States)

Yang, Wuchen; Guo, Dayong; Harris, Marie A.; Cui, Yong; Gluhak-Heinrich, Jelica; Wu, Junjie; Chen, Xiao-Dong; Skinner, Charles; Nyman, Jeffry S.; Edwards, James R.; Mundy, Gregory R.; Lichtler, Alex; Kream, Barbara E.; Rowe, David W.; Kalajzic, Ivo; David, Val; Quarles, Darryl L.; Villareal, Demetri; Scott, Greg; Ray, Manas; Liu, S.; Martin, James F.; Mishina, Yuji; Harris, Stephen E.

2013-01-01

Summary We generated a new Bmp2 conditional-knockout allele without a neo cassette that removes the Bmp2 gene from osteoblasts (Bmp2-cKOob) using the 3.6Col1a1-Cre transgenic model. Bones of Bmp2-cKOob mice are thinner, with increased brittleness. Osteoblast activity is reduced as reflected in a reduced bone formation rate and failure to differentiate to a mature mineralizing stage. Bmp2 in osteoblasts also indirectly controls angiogenesis in the periosteum and bone marrow. VegfA production is reduced in Bmp2-cKOob osteoblasts. Deletion of Bmp2 in osteoblasts also leads to defective mesenchymal stem cells (MSCs), which correlates with the reduced microvascular bed in the periosteum and trabecular bones. Expression of several MSC marker genes (α-SMA, CD146 and Angiopoietin-1) in vivo, in vitro CFU assays and deletion of Bmp2 in vitro in α-SMA+ MSCs support our conclusions. Critical roles of Bmp2 in osteoblasts and MSCs are a vital link between bone formation, vascularization and mesenchymal stem cells. PMID:23843612

Magnetic nanohydroxyapatite/PVA composite hydrogels for promoted osteoblast adhesion and proliferation.

Science.gov (United States)

Hou, Ruixia; Zhang, Guohua; Du, Gaolai; Zhan, Danxia; Cong, Yang; Cheng, Yajun; Fu, Jun

2013-03-01

This paper reports on the systematic investigation of novel magnetic nano-hydroxyapatite/PVA composite hydrogels through cyclic freeze-thawing with controllable structure, mechanical properties, and cell adhesion and proliferation properties. The content of the magnetic nano-hydroxyapatite-coated γ-Fe(2)O(3) (m-nHAP) particles exhibited remarkable influence on the porous structures and compressive strength of the nanocomposite hydrogels. The average pore diameter of the nanocomposite hydrogels exhibited a minimum of 1.6 ± 0.3 μm whereas the compressive strength reached a maximum of about 29.6 ± 6.5 MPa with the m-nHAP content of around 10 wt% in the nanocomposite hydrogels. In order to elucidate the influence of the composite m-nHAP on the cell adhesion and proliferation on the composite hydrogels, the PVA, γ-Fe(2)O(3)/PVA, nHAP/PVA and m-nHAP/PVA hydrogels were seeded and cultured with osteoblasts. The results demonstrated that the osteoblasts preferentially adhered to and proliferated on the m-nHAP/PVA hydrogels, in comparison to the PVA and nHAP/PVA hydrogels, whereas the γ-Fe(2)O(3)/PVA hydrogels appeared most favorable to the osteoblasts. Moreover, with the increasing m-nHAP content in the composite hydrogels, the adhesion density and proliferation of the osteoblasts were significantly promoted, especially at the content of around 50 wt%. Copyright © 2012 Elsevier B.V. All rights reserved.

Transdifferentiation of myoblasts into osteoblasts - possible use for bone therapy.

Science.gov (United States)

Lin, Daphne P L; Carnagarin, Revathy; Dharmarajan, Arun; Dass, Crispin R

2017-12-01

Transdifferentiation is defined as the conversion of one cell type to another and is an ever-expanding field with a growing number of cells found to be capable of such a process. To date, the fact remains that there are limited treatment options for fracture healing, osteoporosis and bone repair post-destruction by bone tumours. Hence, this review focuses on the transdifferentiation of myoblast to osteoblast as a means to further understand the transdifferentiation process and to investigate a potential therapeutic option if successful. The potent osteoinductive effects of the bone morphogenetic protein-2 are largely implicated in the transdifferentiation of myoblast to osteoblast. Bone morphogenetic protein-2-induced activation of the Smad1 protein ultimately results in JunB synthesis, the first transcriptional step in myoblast dedifferentiation. The upregulation of the activating protein-1 binding activity triggers the transcription of the runt-related transcription factor 2 gene, a transcription factor that plays a major role in osteoblast differentiation. This potential transdifferentiation treatment may be utilised for dental implants, fracture healing, osteoporosis and bone repair post-destruction by bone tumours. © 2017 Royal Pharmaceutical Society.

Does methamphetamine affect bone metabolism?

International Nuclear Information System (INIS)

Tomita, Masafumi; Katsuyama, Hironobu; Watanabe, Yoko; Okuyama, Toshiko; Fushimi, Shigeko; Ishikawa, Takaki; Nata, Masayuki; Miyamoto, Osamu

2014-01-01

There is a close relationship between the central nervous system activity and bone metabolism. Therefore, methamphetamine (METH), which stimulates the central nervous system, is expected to affect bone turnover. The aim of this study was to investigate the role of METH in bone metabolism. Mice were divided into 3 groups, the control group receiving saline injections, and the 5 and 10 mg/kg METH groups (n = 6 in each group). All groups received an injection of saline or METH every other day for 8 weeks. Bone mineral density (BMD) was assessed by X-ray computed tomography. We examined biochemical markers and histomorphometric changes in the second cancellous bone of the left femoral distal end. The animals that were administered 5 mg/kg METH showed an increased locomotor activity, whereas those receiving 10 mg/kg displayed an abnormal and stereotyped behavior. Serum calcium and phosphorus concentrations were normal compared to the controls, whereas the serum protein concentration was lower in the METH groups. BMD was unchanged in all groups. Bone formation markers such as alkaline phosphatase and osteocalcin significantly increased in the 5 mg/kg METH group, but not in the 10 mg/kg METH group. In contrast, bone resorption markers such as C-terminal telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b did not change in any of the METH groups. Histomorphometric analyses were consistent with the biochemical markers data. A significant increase in osteoblasts, especially in type III osteoblasts, was observed in the 5 mg/kg METH group, whereas other parameters of bone resorption and mineralization remained unchanged. These results indicate that bone remodeling in this group was unbalanced. In contrast, in the 10 mg/kg METH group, some parameters of bone formation were significantly or slightly decreased, suggesting a low turnover metabolism. Taken together, our results suggest that METH had distinct dose-dependent effects on bone turnover and that

Does methamphetamine affect bone metabolism?

Science.gov (United States)

Tomita, Masafumi; Katsuyama, Hironobu; Watanabe, Yoko; Okuyama, Toshiko; Fushimi, Shigeko; Ishikawa, Takaki; Nata, Masayuki; Miyamoto, Osamu

2014-05-07

There is a close relationship between the central nervous system activity and bone metabolism. Therefore, methamphetamine (METH), which stimulates the central nervous system, is expected to affect bone turnover. The aim of this study was to investigate the role of METH in bone metabolism. Mice were divided into 3 groups, the control group receiving saline injections, and the 5 and 10mg/kg METH groups (n=6 in each group). All groups received an injection of saline or METH every other day for 8 weeks. Bone mineral density (BMD) was assessed by X-ray computed tomography. We examined biochemical markers and histomorphometric changes in the second cancellous bone of the left femoral distal end. The animals that were administered 5mg/kg METH showed an increased locomotor activity, whereas those receiving 10mg/kg displayed an abnormal and stereotyped behavior. Serum calcium and phosphorus concentrations were normal compared to the controls, whereas the serum protein concentration was lower in the METH groups. BMD was unchanged in all groups. Bone formation markers such as alkaline phosphatase and osteocalcin significantly increased in the 5mg/kg METH group, but not in the 10mg/kg METH group. In contrast, bone resorption markers such as C-terminal telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b did not change in any of the METH groups. Histomorphometric analyses were consistent with the biochemical markers data. A significant increase in osteoblasts, especially in type III osteoblasts, was observed in the 5mg/kg METH group, whereas other parameters of bone resorption and mineralization remained unchanged. These results indicate that bone remodeling in this group was unbalanced. In contrast, in the 10mg/kg METH group, some parameters of bone formation were significantly or slightly decreased, suggesting a low turnover metabolism. Taken together, our results suggest that METH had distinct dose-dependent effects on bone turnover and that METH might

Periostin inhibits mechanical stretch-induced apoptosis in osteoblast-like MG-63 cells.

Science.gov (United States)

Yu, Kai-Wen; Yao, Chung-Chen; Jeng, Jiiang-Huei; Shieh, Hao-Ying; Chen, Yi-Jane

2018-04-01

Appropriate mechanical stress plays an important role in regulating the proliferation and differentiation of osteoblasts, whereas high-level mechanical stress may be harmful and compromise cell survival. Periostin, a matricellular protein, is essential in maintaining functional integrity of bone and collagen-rich connective tissue in response to mechanical stress. This study investigated whether or not high-level mechanical stretch induces cell apoptosis and the regulatory role of periostin in mechanical stretch-induced apoptosis in osteoblastic cells. Osteoblast-like MG-63 cells were seeded onto Bio-Flex I culture plates and subjected to cyclic mechanical stretching (15% elongation, 0.1 Hz) in a Flexercell tension plus system-5000. The same process was applied to cells pre-treated with exogenous human recombinant periostin before mechanical stretching. We used a chromatin condensation and membrane permeability dead cell apoptosis kit to evaluate the stretch-induced cell responses. Expression of caspase-3 and cPARP was examined by immunofluorescent stain and flow cytometry. The expression of periostin in MG-63 cells is involved in the TGF-β signaling pathway. High-level cyclic mechanical stretch induced apoptotic responses in MG-63 osteoblastic cells. The percentages of apoptotic cells and cells expressing cPARP protein increased in the groups of cells subjected to mechanical stretch, but these responses were absent in the presence of exogenous periostin. Our study revealed that high-level mechanical stretch induces apoptotic cell death, and that periostin plays a protective role against mechanical stretch-induced apoptosis in osteoblastic cells. Copyright © 2017. Published by Elsevier B.V.

Static and dynamic hypergravity responses of osteoblasts and osteoclasts in medaka scales

OpenAIRE

Yano, Sachiko; Kitamura, Kei-ichiro; Satoh, Yusuke; Nakano, Masaki; Hattori, Atsuhiko; Sekiguchi, Toshio; Ikegame, Mika; Nakashima, Hiroshi; Omori, Katsunori; Hayakawa, Kazuichi; Chiba, Atsuhiko; Sasayama, Yuichi; Ejiri, Sadakazu; Mikuni-Takagaki, Yuko; Mishima, Hiroyuki

2013-01-01

Fish scales are a form of calcified tissue similar to that found in human bone. In medaka scales, we detected both osteoblasts and osteoclasts and subsequently developed a new scale assay system. Using this system, we analyzed the osteoblastic and osteoclastic responses under 2-, 3-, and 4-gravity (G) loading by both centrifugation and vibration. After loading for 10 min, the scales from centrifugal and vibration loading were incubated for 6 and 24 hrs, respectively, after which the osteoblas...

Knockdown of Indian hedgehog protein induces an inhibition of cell growth and differentiation in osteoblast MC3T3‑E1 cells.

Science.gov (United States)

Deng, Ang; Zhang, Hongqi; Hu, Minyu; Liu, Shaohua; Gao, Qile; Wang, Yuxiang; Guo, Chaofeng

2017-12-01

Indian hedgehog protein (Ihh) is evolutionarily conserved and serves important roles in controlling the differentiation of progenitor cells into osteoblasts. Ihh null mutant mice exhibit a failure of osteoblast development in endochondral bone. Although studies have demonstrated that Ihh signaling is a potent local factor that regulates osteoblast differentiation, the specific transcription factors that determine osteoblast differentiation remain unclear. Further studies are required to determine the precise mechanism through which Ihh regulates osteoblast differentiation. In the present study, Ihh was knocked down in osteoblast MC3T3‑E1 cells using short hairpin RNA, to investigate the function of Ihh in osteoblast proliferation and differentiation and to examine the potential mechanism through which Ihh induces osteoblast apoptosis and cell cycle arrest. It was observed that the knockdown of Ihh induced a marked inhibition of cell growth and increased the apoptosis rate compared with the negative control osteoblasts. Downregulation of Ihh resulted in a cell cycle arrest at the G1 to S phase boundary in osteoblasts. In addition, the knockdown of Ihh decreased the alkaline phosphatase activity and mineral deposition of osteoblasts. The inhibitory roles of Ihh downregulation in osteoblast growth and differentiation may be associated with the transforming growth factor‑β/mothers against decapentaplegic homolog and tumor necrosis factor receptor superfamily member 11B/tumor necrosis factor ligand superfamily member 11 signaling pathways. Manipulating either Ihh expression or its signaling components may be of benefit for the treatment of skeletal diseases.

Cuscuta chinensis extract promotes osteoblast differentiation and mineralization in human osteoblast-like MG-63 cells.

Science.gov (United States)

Yang, Hyun Mo; Shin, Hyun-Kyung; Kang, Young-Hee; Kim, Jin-Kyung

2009-02-01

The aim of the present study was to investigate whether the aqueous extract of To-Sa-Za (TSZ-AE), the seed of Cuscuta chinensis Lam., which is a traditional medicinal herb commonly used in Korea and other oriental countries, could induce osteogenic activity in human osteoblast-like MG-63 cells. TSZ-AE treatment mildly promoted the proliferation of MG-63 cells at doses of 500 and 1,000 microg/mL in the 24-hour culture period. Dose-dependent increases in alkaline phosphatase (ALP) activity and collagen synthesis were shown at 48 and 72 hours of incubation. The release of bone morphogenetic protein (BMP)-2 but not osteocalcin in the MG-63 cells was induced by TSZ-AE at 72 hours (100-1,000 microg/mL). In addition, TSZ-AE markedly increased mRNA expression of ALP, collagen, and BMP-2 in the MG-63 cells in a dose-dependent manner. Mineralization in the culture of MG-63 cells was significantly induced at 500 and 1,000 microg/mL TSZ-AE treatment. In conclusion, this study shows that TSZ-AE enhanced ALP activity, collagen synthesis, BMP-2 expression, and mineralization in MG-63 cells. These results strongly suggest that C. chinensis can play an important role in osteoblastic bone formation and may possibly lead to the development of bone-forming drugs.

Retinoic acid receptor signalling directly regulates osteoblast and adipocyte differentiation from mesenchymal progenitor cells

Energy Technology Data Exchange (ETDEWEB)

Green, A.C. [St Vincent' s Institute, Fitzroy, Victoria 3065 (Australia); Department of Medicine at St. Vincent' s Hospital, The University of Melbourne, Victoria 3065 (Australia); Kocovski, P.; Jovic, T.; Walia, M.K. [St Vincent' s Institute, Fitzroy, Victoria 3065 (Australia); Chandraratna, R.A.S. [IO Therapeutics, Inc., Santa Ana, CA 92705 (United States); Martin, T.J.; Baker, E.K. [St Vincent' s Institute, Fitzroy, Victoria 3065 (Australia); Department of Medicine at St. Vincent' s Hospital, The University of Melbourne, Victoria 3065 (Australia); Purton, L.E., E-mail: lpurton@svi.edu.au [St Vincent' s Institute, Fitzroy, Victoria 3065 (Australia); Department of Medicine at St. Vincent' s Hospital, The University of Melbourne, Victoria 3065 (Australia)

2017-01-01

Low and high serum retinol levels are associated with increased fracture risk and poor bone health. We recently showed retinoic acid receptors (RARs) are negative regulators of osteoclastogenesis. Here we show RARs are also negative regulators of osteoblast and adipocyte differentiation. The pan-RAR agonist, all-trans retinoic acid (ATRA), directly inhibited differentiation and mineralisation of early osteoprogenitors and impaired the differentiation of more mature osteoblast populations. In contrast, the pan-RAR antagonist, IRX4310, accelerated differentiation of early osteoprogenitors. These effects predominantly occurred via RARγ and were further enhanced by an RARα agonist or antagonist, respectively. RAR agonists similarly impaired adipogenesis in osteogenic cultures. RAR agonist treatment resulted in significant upregulation of the Wnt antagonist, Sfrp4. This accompanied reduced nuclear and cytosolic β-catenin protein and reduced expression of the Wnt target gene Axin2, suggesting impaired Wnt/β-catenin signalling. To determine the effect of RAR inhibition in post-natal mice, IRX4310 was administered to male mice for 10 days and bones were assessed by µCT. No change to trabecular bone volume was observed, however, radial bone growth was impaired. These studies show RARs directly influence osteoblast and adipocyte formation from mesenchymal cells, and inhibition of RAR signalling in vivo impairs radial bone growth in post-natal mice. - Graphical abstract: Schematic shows RAR ligand regulation of osteoblast differentiation in vitro. RARγ antagonists±RARα antagonists promote osteoblast differentiation. RARγ and RARα agonists alone or in combination block osteoblast differentiation, which correlates with upregulation of Sfrp4, and downregulation of nuclear and cytosolic β-catenin and reduced expression of the Wnt target gene Axin2. Red arrows indicate effects of RAR agonists on mediators of Wnt signalling.

Osteoblastic response to pectin nanocoating on titanium surfaces

DEFF Research Database (Denmark)

Gurzawska, Katarzyna; Svava, Rikke; Yihua, Yu

2014-01-01

with respect to surface properties and osteogenic response in osteoblastic cells. Nanocoatings on titanium surfaces were evaluated by scanning electron microscopy, contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy. The effect of coated RG-Is on cell adhesion, cell...

Differences in responses to X-ray exposure between osteoclast and osteoblast cells

International Nuclear Information System (INIS)

Zhang, Jian; Wang, Ziyang; Wu, Anqing; Nie, Jing; Pei, Hailong; Hu, Wentao; Wang, Bing; Shang, Peng; Li, Bingyan; Zhou, Guangming

2017-01-01

Radiation-induced bone loss is a potential health concern for cancer patients undergoing radiotherapy. Enhanced bone resorption by osteoclasts and decreased bone formation by osteoblasts were thought to be the main reasons. In this study, we showed that both pre-differentiating and differentiating osteoclasts were relatively sensitive to X-rays compared with osteoblasts. X-rays decreased cell viability to a greater degree in RAW264.7 cells and in differentiating cells than than in osteoblastic MC3T3-E1 cells. X-rays at up to 8 Gy had little effects on osteoblast mineralization. In contrast, X-rays at 1 Gy induced enhanced osteoclastogenesis by enhanced cell fusion, but had no effects on bone resorption. A higher dose of X-rays at 8 Gy, however, had an inhibitory effect on bone resorption. In addition, actin ring formation was disrupted by 8 Gy of X-rays and reorganized into clusters. An increased activity of Caspase 3 was found after X-ray exposure. Actin disorganization and increased apoptosis may be the potential effects of X-rays at high doses, by inhibiting osteoclast differentiation. Taken together, our data indicate high radiosensitivity of osteoclasts. X-ray irradiation at relatively low doses can activate osteoclastogenesis, but not osteogenic differentiation. The radiosensitive osteoclasts are the potentially responsive cells for X-ray-induced bone loss.

Low-intensity pulsed ultrasound regulates proliferation and differentiation of osteoblasts through osteocytes

International Nuclear Information System (INIS)

Li, Lei; Yang, Zheng; Zhang, Hai; Chen, Wenchuan; Chen, Mengshi; Zhu, Zhimin

2012-01-01

Highlights: ► CM from LIPUS-stimulated osteocytes inhibits proliferation of osteoblasts. ► CM from LIPUS-stimulated osteocytes enhances differentiation of osteoblasts. ► LIPUS stimulates MLO-Y4 cells to secrete PGE 2 and NO. -- Abstract: Low-intensity pulsed ultrasound (LIPUS) has been used as a safe and effective modality to enhance fracture healing. As the most abundant cells in bone, osteocytes orchestrate biological activities of effector cells via direct cell-to-cell contacts and by soluble factors. In this study, we have used the osteocytic MLO-Y4 cells to study the effects of conditioned medium from LIPUS-stimulated MLO-Y4 cells on proliferation and differentiation of osteoblastic MC3T3-E1 cells. Conditioned media from LIPUS-stimulated MLO-Y4 cells (LIPUS-Osteocyte-CM) were collected and added on MC3T3-E1 cell cultures. MC3T3-E1 cells cultured in LIPUS-Osteocyte-CM demonstrated a significant inhibition of proliferation and an increased alkaline phosphatase activity. The results of PGE 2 and NO assay showed that LIPUS could enhance PGE 2 and NO secretion from MLO-Y4 cells at all time points within 24 h after LIPUS stimulation. We conclude that LIPUS regulates proliferation and differentiation of osteoblasts through osteocytes in vitro. Increased secretion of PGE 2 from osteocytes may play a role in this effect.

In vitro response of pre-osteoblastic cells to laser microgrooved PEEK

International Nuclear Information System (INIS)

Cordero, D; López-Álvarez, M; Rodríguez-Valencia, C; Serra, J; Chiussi, S; González, P

2013-01-01

Polyetheretherketone (PEEK) is currently being used in implants as an alternative to titanium, due to its mechanical properties, cytocompatibility and inertness. Several studies have demonstrated that certain patterning on the implants promotes the oriented cell growth of osteoblasts, favouring the formation of bone tissue. This patterning improves the implant's osteointegration in the bone and its mechanical stability. Therefore, the objective of this work is to micro-structure PEEK by laser radiation and to carry out an exhaustive study of the orientation of pre-osteoblast cells that grow on this material. Parallel microgrooves were obtained using an ArF excimer laser coupled with a mask projection unit with distances of 25, 50, 75 and 100 µm between grooves. The cell growth on these PEEK surfaces was studied, in order to compare the effect of different distances between grooves on the biological response of MC3T3-E1 pre-osteoblastic cells. Preferential cell orientation was observed for all studied distances, which was more pronounced in the 25 and 50 µm ones. (paper)

Cell fusion in osteoclasts plays a critical role in controlling bone mass and osteoblastic activity

International Nuclear Information System (INIS)

Iwasaki, Ryotaro; Ninomiya, Ken; Miyamoto, Kana; Suzuki, Toru; Sato, Yuiko

2008-01-01

The balance between osteoclast and osteoblast activity is central for maintaining the integrity of bone homeostasis. Here we show that mice lacking dendritic cell specific transmembrane protein (DC-STAMP), an essential molecule for osteoclast cell-cell fusion, exhibited impaired bone resorption and upregulation of bone formation by osteoblasts, which do not express DC-STAMP, which led to increased bone mass. On the contrary, DC-STAMP over-expressing transgenic (DC-STAMP-Tg) mice under the control of an actin promoter showed significantly accelerated cell-cell fusion of osteoclasts and bone resorption, with decreased osteoblastic activity and bone mass. Bone resorption and formation are known to be regulated in a coupled manner, whereas DC-STAMP regulates bone homeostasis in an un-coupled manner. Thus our results indicate that inhibition of a single molecule provides both decreased osteoclast activity and increased bone formation by osteoblasts, thereby increasing bone mass in an un-coupled and a tissue specific manner.

Effects of nano-emulsion preparations of tocopherols and tocotrienols on oxidative stress and osteoblast differentiation

Directory of Open Access Journals (Sweden)

Song Liang-Song

2017-01-01

Full Text Available Tocopherols and tocotrienols are two groups of compounds in the vitamin E family, of which the tocopherols are widely used as antioxidant dietary supplements. Recent studies have shown mixed observations for tocopherol functions in bone homeostasis. We have evaluated the potency of suspension- and nano-emulsion formulation-based delivery of different vitamin E family members in lipopolysaccharide (LPS-induced oxidative stress and osteoblast differentiation. Our results showed the both tocopherols and tocotrienols could reduce oxidative stress as evaluated by the levels of reactive oxygen species (ROS. Their effects were enhanced when applied in the nano-emulsion mode of delivery due to increased bioavailability. In addition, our results showed that tocotrienols increased osteoblast differentiation, while tocopherols showed reduced osteoblast differentiation, which may be due to their differential effects on SMAD and p65 signaling. Together, these findings indicate that tocotrienols delivered through nano-emulsion exhibit superior antioxidant properties and osteoblast differentiation, and could serve as a better alternative to tocopherol-based vitamin E supplements.

New peptides players in metabolic disorders

Directory of Open Access Journals (Sweden)

Agata Mierzwicka

2016-08-01

Full Text Available Among new peptides responsible for the pathogenesis of metabolic disorders and carbohydrate metabolism, adipokines are of great importance. Adipokines are substances of hormonal character, secreted by adipose tissue. Apart from the well-known adipokines, adropin and preptin are relatively newly discovered, hence their function is not fully understood. They are peptides not secreted by adipose tissue but their role in the metabolic regulations seems to be significant. Preptin is a 34-amino acid peptide, a derivative of proinsulin growth factor II (pro-IGF-II, secreted by pancreatic β cells, considered to be a physiological enhancer of insulin secretion. Additionally, preptin has a stimulating effect on osteoblasts, inducing their proliferation, differentiation and survival. Adropin is a 76-amino acid peptide, encoded by the energy homeostasis associated gene (Enho, mainly in liver and brain, and its expression is dependent on a diet. Adropin is believed to play an important role in metabolic homeostasis, fatty acids metabolism control, insulin resistance prevention, dyslipidemia, and impaired glucose tolerance. The results of studies conducted so far show that the diseases resulting from metabolic syndrome, such as obesity, type 2 diabetes mellitus, polycystic ovary syndrome, non-alcoholic fatty liver disease, or cardiovascular disease are accompanied by significant changes in the concentration of these peptides. It is also important to note that preptin has an anabolic effect on bone tissue, which might be preventive in osteoporosis.

Distribution of type VI collagen in association with osteoblast lineages in the groove of Ranvier during rat postnatal development.

Science.gov (United States)

Kohara, Yukihiro; Soeta, Satoshi; Izu, Yayoi; Arai, Kiyotaka; Amasaki, Hajime

2016-11-01

In the groove of Ranvier (GOR), osteoblast lineages form bone bark, which develops into endosteal cortical bone. This ossification process is thought to be regulated by the microenvironment in the GOR. Type VI collagen (Col VI), an extracellular matrix (ECM) protein found in the periosteum/perichondrium, mediates osteoblast differentiation via the cell-surface receptor neural/glial antigen 2 (NG2) chondroitin sulfate proteoglycan. In order to clarify the function of Col VI during osteoblast differentiation in the GOR, in the present study, we examined the distribution of Col VI and osteoblast lineages expressing NG2 in the rat tibia proximal end during postnatal growing periods by immunohistochemistry. Our data revealed that Col VI accumulated in the ECM of the GOR middle layer and that Col VI accumulation was reduced and disappeared in the inner and middle lower regions. Runt-related transcription factor 2-immunoreactive pre-osteoblasts expressed NG2 in Col VI-immunopositive areas. However, Osterix-immunoreactive mature osteoblasts were only found in the Col VI-immunonegative area. These findings indicate that Col VI provided a characteristic microenvironment in the GOR and that NG2-Col VI interactions may regulate the differentiation of osteoblast lineages prior to terminal maturation. Copyright © 2016 Elsevier GmbH. All rights reserved.

Osteoblastic Metastases Mimickers on Contrast Enhanced CT

Directory of Open Access Journals (Sweden)

Fahad Al-Lhedan

2017-01-01

Full Text Available Secondary osseous involvement in lymphoma is more common compared to primary bone lymphoma. The finding of osseous lesion can be incidentally discovered during the course of the disease. However, osseous metastases are infrequently silent. Detection of osseous metastases is crucial for accurate staging and optimal treatment planning of lymphoma. The aim of imaging is to identify the presence and extent of osseous disease and to assess for possible complications such as pathological fracture of the load-bearing bones and cord compression if the lesion is spinal. We are presenting two patients with treated lymphoma who were in complete remission. On routine follow-up contrast enhanced CT, there were new osteoblastic lesions in the spine worrisome for metastases. Additional studies were performed for further evaluation of both of them which did not demonstrate any corresponding suspicious osseous lesion. The patients have a prior history of chronic venous occlusive thrombosis that resulted in collaterals formation. Contrast enhancement of the vertebral body marrow secondary to collaterals formation and venous flow through the vertebral venous plexus can mimic the appearance of spinal osteoblastic metastases.

Integrin expression by human osteoblasts cultured on degradable polymeric materials applicable for tissue engineered bone.

Science.gov (United States)

El-Amin, Saadiq F; Attawia, Mohamed; Lu, Helen H; Shah, Asist K; Chang, Richard; Hickok, Noreen J; Tuan, Rocky S; Laurencin, Cato T

2002-01-01

The use of biodegradable polymers in the field of orthopaedic surgery has gained increased popularity, as surgical pins and screws, and as potential biological scaffolds for repairing cartilage and bone defects. One such group of polymers that has gained considerable attention are the polyesters, poly(lactide-co-glycolide) (PLAGA) and polylactic acid (PLA), because of their minimal tissue inflammatory response, favorable biocompatibility and degradation characteristics. The objective of this study was to evaluate human osteoblastic cell adherence and growth on PLAGA and PLA scaffolds by examining integrin receptor (alpha2, alpha3, alpha4, alpha5, alpha6 and beta1) expression. Primary human osteoblastic cells isolated from trabecular bone adhered efficiently to both PLAGA and PLA, with the rate of adherence on PLAGA comparable to that of control tissue culture polystyrene (TCPS), and significantly higher than on PLA polymers at 3, 6 and 12 h. Human osteoblastic phenotypic expression, alkaline phosphatase (ALP) activity was positive on both degradable matrices, whereas osteocalcin levels were significantly higher on cells grown on PLAGA than on PLA composites. Interestingly, the integrin subunits, alpha2, alpha3, alpha4, alpha5, alpha6 and beta1 were all expressed at higher levels by osteoblasts cultured on PLAGA than those on PLA as analyzed by westerns blots and by flow cytometry. Among the integrins, alpha2, beta5 and beta1 showed the greatest difference in levels between the two surfaces. Thus, both PLA and PLAGA support osteoblastic adhesion and its accompanying engagement of integrin receptor and expression of osteocalcin and ALP. However PLAGA consistently appeared to be a better substrate for osteoblastic cells based on these parameters. This study is one of the first to investigate the ability of primary human osteoblastic cells isolated from trabecular bone to adhere to the biodegradable polymers PLAGA and PLA, and to examine the expression of their key

Nanoparticles prepared from the water extract of Gusuibu (Drynaria fortunei J. Sm. protects osteoblasts against insults and promotes cell maturation

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Hsu C-K

2011-07-01

Full Text Available Chung-King Hsu1,2, Mei-Hsiu Liao3, Yu-Tyng Tai4, Shing-Hwa Liu5, Keng-Liang Ou6, Hsu-Wei Fang7, I-Jung Lee8, Ruei-Ming Chen2,31Institute of Materials Science and Engineering, National Taipei University of Technology, 2Cell Physiology and Molecular Image Research Center, Taipei Medical University-Wan Fang Medical Center, 3Graduate Institute of Medical Sciences, Taipei Medical University, 4Department of Anesthesiology, Taipei Medical University-Wan Fang Medical Center, 5Institute of Toxicology, College of Medicine, National Taiwan University, 6Graduate Institute of Biomedical Materials and Engineering, Taipei Medical University, 7Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, 8Division of Information and Herbarium, National Research Institute of Chinese Medicine, Taipei, TaiwanAbstract: Our previous study showed that Gusuibu (Drynaria fortunei J. Sm. can stimulate osteoblast maturation. This study was further designed to evaluate the effects of nanoparticles prepared from the water extract of Gusuibu (WEG on osteoblast survival and maturation. Primary osteoblasts were exposed to 1, 10, 100, and 1000 µg/mL nanoparticles of WEG (nWEG for 24, 48, and 72 hours did not affect morphologies, viability, or apoptosis of osteoblasts. In comparison, treatment of osteoblasts with 1000 µg/mL WEG for 72 hours decreased cell viability and induced DNA fragmentation and cell apoptosis. nWEG had better antioxidant bioactivity in protecting osteoblasts from oxidative and nitrosative stress-induced apoptosis than WEG. In addition, nWEG stimulated greater osteoblast maturation than did WEG. Therefore, this study shows that WEG nanoparticles are safer to primary osteoblasts than are normal-sized products, and may promote better bone healing by protecting osteoblasts from apoptotic insults, and by promoting osteogenic maturation.Keywords: Gusuibu, nanoparticles, cell protection, osteoblast maturation

Rebamipide delivered by brushite cement enhances osteoblast and macrophage proliferation.

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Michael Pujari-Palmer

Full Text Available Many of the bioactive agents capable of stimulating osseous regeneration, such as bone morphogenetic protein-2 (BMP-2 or prostaglandin E2 (PGE2, are limited by rapid degradation, a short bioactive half-life at the target site in vivo, or are prohibitively expensive to obtain in large quantities. Rebamipide, an amino acid modified hydroxylquinoline, can alter the expression of key mediators of bone anabolism, cyclo-oxygenase 2 (COX-2, BMP-2 and vascular endothelial growth factor (VEGF, in diverse cell types such as mucosal and endothelial cells or chondrocytes. The present study investigates whether Rebamipide enhances proliferation and differentiation of osteoblasts when delivered from brushite cement. The reactive oxygen species (ROS quenching ability of Rebampide was tested in macrophages as a measure of bioactivity following drug release incubation times, up to 14 days. Rebamipide release from brushite occurs via non-fickian diffusion, with a rapid linear release of 9.70% ± 0.37% of drug per day for the first 5 days, and an average of 0.5%-1% per day thereafter for 30 days. Rebamipide slows the initial and final cement setting time by up to 3 and 1 minute, respectively, but does not significantly reduce the mechanical strength below 4% (weight percentage. Pre-osteoblast proliferation increases by 24% upon exposure to 0.4 uM Rebamipide, and by up to 73% when Rebamipide is delivered via brushite cement. Low doses of Rebamipide do not adversely affect peak alkaline phosphatase activity in differentiating pre-osteoblasts. Rebamipide weakly stimulates proliferation in macrophages at low concentrations (118 ± 7.4% at 1 uM, and quenches ROS by 40-60%. This is the first investigation of Rebamipide in osteoblasts.

Linarin isolated from Buddleja officinalis prevents hydrogen peroxide-induced dysfunction in osteoblastic MC3T3-E1 cells.

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Kim, Young Ho; Lee, Young Soon; Choi, Eun Mi

2011-01-01

The flowers and leaves buds of Buddleja officinalis MAXIM (Buddlejaceae) are used to treat eye troubles, hernia, gonorrhea and liver troubles in Asia. To elucidate the protective effects of linarin isolated from B. officinalis on the response of osteoblast to oxidative stress, osteoblastic MC3T3-E1 cells were pre-incubated with linarin for 1h before treatment with 0.3mM H(2)O(2) for 48h, and markers of osteoblast function and oxidative damage were examined. Linarin significantly (P<0.05) increased cell survival, alkaline phosphatase (ALP) activity, collagen content, calcium deposition, and osteocalcin secretion and decreased the production of receptor activator of nuclear factor-kB ligand (RANKL), protein carbonyl (PCO), and malondialdehyde (MDA) of osteoblastic MC3T3-E1 cells in the presence of hydrogen peroxide. These results demonstrate that linarin can protect osteoblasts against hydrogen peroxide-induced osteoblastic dysfunction and may exert anti-resorptive actions, at least in part, via the reduction of RANKL and oxidative damage. 2011 Elsevier Inc. All rights reserved.

Enhancement of osteoblastic differentiation in alginate gel beads with bioactive octacalcium phosphate particles

International Nuclear Information System (INIS)

Endo, Kosei; Anada, Takahisa; Suzuki, Osamu; Yamada, Masumi; Seki, Minoru; Sasaki, Keiichi

2015-01-01

The present study investigated whether alginate (Alg) hydrogel microbeads have a role in maintaining mouse bone marrow stromal ST-2 cells and release the cells after being stimulated by synthetic octacalcium phosphate (OCP), which is a mineral crystal capable of stimulating osteoblastic differentiation during a conversion process to hydroxyapatite (HA). The ST-2 cell suspension in the alginate solution, which contained various concentrations of OCP granules with diameters less than 53 μm, was extruded drop-wise into a stirred gelation solution containing BaCl 2 using an encapsulator with nitrogen gas stream. The Alg-microbeads (Alg/OCP · ST-2 microbeads) that were generated, which had a diameter of approximately 400 μm, were incubated for up to 14 d and then assessed for osteoblastic differentiation. Alg-microbeads with cells were also incubated to identify the possible conversion from OCP to HA. Osteoblast differentiation markers in ST-2 cells, alkaline phosphatase (ALP) and collagen type I, were up-regulated in the presence of higher amounts of OCP. X-ray diffraction analysis and Fourier transform infrared spectroscopy confirmed that the OCP tended to convert to HA over time, suggesting that the OCP in Alg-microbeads interacts three-dimensionally with ST-2 cells and stimulates its osteoblastic differentiation. The release of ST-2 cells from the microbeads was also estimated. ST-2 cells were identified outside of the microbeads, although the cell number tended to decrease with increasing OCP. These results suggest that Alg/OCP microbeads could be used as a vehicle to activate osteoblastic cells and deliver them to sites where bone regeneration is needed. (paper)

Zirconium ions up-regulate the BMP/SMAD signaling pathway and promote the proliferation and differentiation of human osteoblasts.

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Yongjuan Chen

Full Text Available Zirconium (Zr is an element commonly used in dental and orthopedic implants either as zirconia (ZrO2 or in metal alloys. It can also be incorporated into calcium silicate-based ceramics. However, the effects of in vitro culture of human osteoblasts (HOBs with soluble ionic forms of Zr have not been determined. In this study, primary culture of human osteoblasts was conducted in the presence of medium containing either ZrCl4 or Zirconium (IV oxynitrate (ZrO(NO32 at concentrations of 0, 5, 50 and 500 µM, and osteoblast proliferation, differentiation and calcium deposition were assessed. Incubation of human osteoblast cultures with Zr ions increased the proliferation of human osteoblasts and also gene expression of genetic markers of osteoblast differentiation. In 21 and 28 day cultures, Zr ions at concentrations of 50 and 500 µM increased the deposition of calcium phosphate. In addition, the gene expression of BMP2 and BMP receptors was increased in response to culture with Zr ions and this was associated with increased phosphorylation of SMAD1/5. Moreover, Noggin suppressed osteogenic gene expression in HOBs co-treated with Zr ions. In conclusion, Zr ions appear able to induce both the proliferation and the differentiation of primary human osteoblasts. This is associated with up-regulation of BMP2 expression and activation of BMP signaling suggesting this action is, at least in part, mediated by BMP signaling.

Zirconium Ions Up-Regulate the BMP/SMAD Signaling Pathway and Promote the Proliferation and Differentiation of Human Osteoblasts

Science.gov (United States)

Chen, Yongjuan; Roohani-Esfahani, Seyed-Iman; Lu, ZuFu; Zreiqat, Hala; Dunstan, Colin R.

2015-01-01

Zirconium (Zr) is an element commonly used in dental and orthopedic implants either as zirconia (ZrO2) or in metal alloys. It can also be incorporated into calcium silicate-based ceramics. However, the effects of in vitro culture of human osteoblasts (HOBs) with soluble ionic forms of Zr have not been determined. In this study, primary culture of human osteoblasts was conducted in the presence of medium containing either ZrCl4 or Zirconium (IV) oxynitrate (ZrO(NO3)2) at concentrations of 0, 5, 50 and 500 µM, and osteoblast proliferation, differentiation and calcium deposition were assessed. Incubation of human osteoblast cultures with Zr ions increased the proliferation of human osteoblasts and also gene expression of genetic markers of osteoblast differentiation. In 21 and 28 day cultures, Zr ions at concentrations of 50 and 500 µM increased the deposition of calcium phosphate. In addition, the gene expression of BMP2 and BMP receptors was increased in response to culture with Zr ions and this was associated with increased phosphorylation of SMAD1/5. Moreover, Noggin suppressed osteogenic gene expression in HOBs co-treated with Zr ions. In conclusion, Zr ions appear able to induce both the proliferation and the differentiation of primary human osteoblasts. This is associated with up-regulation of BMP2 expression and activation of BMP signaling suggesting this action is, at least in part, mediated by BMP signaling. PMID:25602473

Short communication: selective cytotoxicity of curcumin on osteosarcoma cells compared to healthy osteoblasts

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Chang R

2014-01-01

Full Text Available Run Chang,1 Linlin Sun,1 Thomas J Webster1,21Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 2Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi ArabiaAbstract: Curcumin is a natural phenolic compound extracted from the plant Curcuma longa L. In previous studies, curcumin has been shown to have anticancer, antioxidant, and anti-inflammatory effects. In this study, the cytotoxicity of different concentrations (5, 10, 25, 50, 75, and 100 µM of curcumin dissolved in dimethyl sulfoxide was compared between MG-63 osteosarcoma and healthy human osteoblast cells. Consequently, the viability of osteosarcoma cells was less than 50% at a concentration of 10 µM compared to the control sample without curcumin, but healthy osteoblast cells had at least 80% viability throughout all the concentrations tested. The results demonstrated that MG-63 osteosarcoma cells were much more sensitive in terms of cytotoxicity to curcumin, while the healthy human osteoblasts exhibited a higher healthy viability after 24 hours of curcumin treatment. Therefore, this study showed that at the right concentrations (5 µM to 25 µM, curcumin, along with a proper nanoparticle drug delivery carrier, may selectively kill bone cancer cells over healthy bone cells.Keywords: curcumin, osteosarcoma, human osteoblast, viability, bone cancer

Receptors and effects of gut hormones in three osteoblastic cell lines

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Wilson Peter JM

2011-07-01

Full Text Available Abstract Background In recent years the interest on the relationship of gut hormones to bone processes has increased and represents one of the most interesting aspects in skeletal research. The proportion of bone mass to soft tissue is a relationship that seems to be controlled by delicate and subtle regulations that imply "cross-talks" between the nutrient intake and tissues like fat. Thus, recognition of the mechanisms that integrate a gastrointestinal-fat-bone axis and its application to several aspects of human health is vital for improving treatments related to bone diseases. This work analysed the effects of gut hormones in cell cultures of three osteoblastic cell lines which represent different stages in osteoblastic development. Also, this is the first time that there is a report on the direct effects of glucagon-like peptide 2, and obestatin on osteoblast-like cells. Methods mRNA expression levels of five gut hormone receptors (glucose-dependent insulinotropic peptide [GIP], glucagon-like peptide 1 [GLP-1], glucagon-like peptide 2 [GLP-2], ghrelin [GHR] and obestatin [OB] were analysed in three osteoblastic cell lines (Saos-2, TE-85 and MG-63 showing different stages of osteoblast development using reverse transcription and real time polymerase chain reaction. The responses to the gut peptides were studied using assays for cell viability, and biochemical bone markers: alkaline phosphatase (ALP, procollagen type 1 amino-terminal propeptides (P1NP, and osteocalcin production. Results The gut hormone receptor mRNA displayed the highest levels for GIP in Saos-2 and the lowest levels in MG-63, whereas GHR and GPR39 (the putative obestatin receptor expression was higher in TE-85 and MG-63 and lower in Saos-2. GLP-1 and GLP-2 were expressed only in MG-63 and TE-85. Treatment of gut hormones to cell lines showed differential responses: higher levels in cell viability in Saos-2 after GIP, in TE-85 and MG-63 after GLP-1, GLP-2, ghrelin and

Evaluation of World Wide Web-based Lessons for a First Year Dental Biochemistry Course

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Dr. Alan E. Levine

2002-11-01

Full Text Available First year dental students at The University of Texas Dental Branch at Houston (Dental Branch are required to take a basic biochemistry course. To facilitate learning and allow student self-assessment of their progress, WWW-based lessons covering intermediary metabolism were developed as a supplement to traditional lectures. Lesson design combined text, graphics, and animations and included learner control, links to other learning resources, and practice exercises and exams with immediate feedback. Results from an on-line questionnaire completed by students in two different classes showed that they completed 50% of the lessons and spent an average of 4 hrs. on-line. A majority of the students either agreed or strongly agreed that practice exercises were helpful, that the ability to control the pace of the lessons was important, that the lesson structure and presentation was easy to follow, that the illustrations, animations, and hyperlinks were helpful, and that the lessons were effective as a review. The very positive response to the WWW-based lessons indicates the usefulness of this approach as a study aid for dental students.

Changes in the insulin-like growth factor-system may contribute to in vitro age-related impaired osteoblast functions

DEFF Research Database (Denmark)

Kveiborg, M.; Rattan, Suresh; Clark, B.F.C.

2000-01-01

Age-related bone loss is thought to be due to impaired osteoblast functions. Insulin-like growth factors (IGFs) have been shown to be important stimulators of bone formation and osteoblast activities in vitro and in vivo. We tested the hypothesis that in vitro osteoblast senescence is associated ...

Estrogen binding, receptor mRNA, and biologic response in osteoblast-like osteosarcoma cells

International Nuclear Information System (INIS)

Komm, B.S.; Terpening, C.M.; Benz, D.J.; Graeme, K.A.; Gallegos, A.; Korc, M.; Greene, G.L.; O'Malley, B.W.; Haussler, M.R.

1988-01-01

High specific activity estradiol labeled with iodine-125 was used to detect approximately 200 saturable, high-affinity (dissociation constant approximately equal to 1.0 nM) nuclear binding sites in rat (ROS 17/2.8) and human (HOS TE85) clonal osteoblast-like osteosarcoma cells. Of the steroids tested, only testosterone exhibited significant cross-reactivity with estrogen binding. RNA blot analysis with a complementary DNA probe to the human estrogen receptor revealed putative receptor transcripts of 6 to 6.2 kilobases in both rat and human osteosarcoma cells. Type I procollagen and transforming growth factor-beta messenger RNA levels were enhanced in cultured human osteoblast-like cells treated with 1 nM estradiol. Thus, estrogen can act directly on osteoblasts by a receptor-mediated mechanism and thereby modulate the extracellular matrix and other proteins involved in the maintenance of skeletal mineralization and remodeling

Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive G{sub s}–G protein signaling in osteoblasts

Energy Technology Data Exchange (ETDEWEB)

Wattanachanya, Lalita, E-mail: lalita_md@yahoo.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok (Thailand); Wang, Liping, E-mail: lipingwang05@yahoo.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Millard, Susan M., E-mail: susan.millard@mater.uq.edu.au [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Lu, Wei-Dar, E-mail: weidar_lu@yahoo.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); O’Carroll, Dylan, E-mail: dylancocarroll@gmail.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Hsiao, Edward C., E-mail: Edward.Hsiao@ucsf.edu [Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA (United States); Conklin, Bruce R., E-mail: bconklin@gladstone.ucsf.edu [Gladstone Institute of Cardiovascular Disease, San Francisco, CA (United States); Department of Medicine, University of California, San Francisco, CA (United States); Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA (United States); Nissenson, Robert A., E-mail: Robert.Nissenson@ucsf.edu [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States)

2015-05-01

G protein-coupled receptor (GPCR) signaling in osteoblasts (OBs) is an important regulator of bone formation. We previously described a mouse model expressing Rs1, an engineered constitutively active G{sub s}-coupled GPCR, under the control of the 2.3 kb Col I promoter. These mice showed a dramatic age-dependent increase in trabecular bone of femurs. Here, we further evaluated the effects of enhanced G{sub s} signaling in OBs on intramembranous bone formation by examining calvariae of 1- and 9-week-old Col1(2.3)/Rs1 mice and characterized the in vivo gene expression specifically occurring in osteoblasts with activated G{sub s} G protein-coupled receptor signaling, at the cellular level rather than in a whole bone. Rs1 calvariae displayed a dramatic increase in bone volume with partial loss of cortical structure. By immunohistochemistry, Osterix was detected in cells throughout the inter-trabecular space while Osteocalcin was expressed predominantly in cells along bone surfaces, suggesting the role of paracrine mediators secreted from OBs driven by 2.3 kb Col I promoter could influence early OB commitment, differentiation, and/or proliferation. Gene expression analysis of calvarial OBs revealed that genes affected by Rs1 signaling include those encoding proteins important for cell differentiation, cytokines and growth factors, angiogenesis, coagulation, and energy metabolism. The set of G{sub s}-GPCRs and other GPCRs that may contribute to the observed skeletal phenotype and candidate paracrine mediators of the effect of G{sub s} signaling in OBs were also determined. Our results identify novel detailed in vivo cellular changes of the anabolic response of the skeleton to G{sub s} signaling in mature OBs. - Highlights: • OB expression of an engineered G{sub s}-coupled receptor dramatically increases bone mass. • We investigated the changes in gene expression in vivo in enhanced OB G{sub s} signaling. • Genes in cell cycle and transcription were increased in

Smart biomaterials: Surfaces functionalized with proteolytically stable osteoblast-adhesive peptides

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Annj Zamuner

2017-09-01

Full Text Available Engineered scaffolds for bone tissue regeneration are designed to promote cell adhesion, growth, proliferation and differentiation. Recently, covalent and selective functionalization of glass and titanium surfaces with an adhesive peptide (HVP mapped on [351–359] sequence of human Vitronectin allowed to selectively increase osteoblast attachment and adhesion strength in in vitro assays, and to promote osseointegration in in vivo studies. For the first time to our knowledge, in this study we investigated the resistance of adhesion sequences to proteolytic digestion: HVP was completely cleaved after 5 h. In order to overcome the enzymatic degradation of the native peptide under physiological conditions we synthetized three analogues of HVP sequence. A retro-inverted peptide D-2HVP, composed of D amino acids, was completely stable in serum-containing medium. In addition, glass surfaces functionalized with D-2HVP increased human osteoblast adhesion as compared to the native peptide and maintained deposition of calcium. Interestingly, D-2HVP increased expression of IBSP, VTN and SPP1 genes as compared to HVP functionalized surfaces. Total internal reflection fluorescence microscope analysis showed cells with numerous filopodia spread on D-2HVP-functionalized surfaces. Therefore, the D-2HVP sequence is proposed as new osteoblast adhesive peptide with increased bioactivity and high proteolytic resistance.

Smart biomaterials: Surfaces functionalized with proteolytically stable osteoblast-adhesive peptides.

Science.gov (United States)

Zamuner, Annj; Brun, Paola; Scorzeto, Michele; Sica, Giuseppe; Castagliuolo, Ignazio; Dettin, Monica

2017-09-01

Engineered scaffolds for bone tissue regeneration are designed to promote cell adhesion, growth, proliferation and differentiation. Recently, covalent and selective functionalization of glass and titanium surfaces with an adhesive peptide (HVP) mapped on [351-359] sequence of human Vitronectin allowed to selectively increase osteoblast attachment and adhesion strength in in vitro assays, and to promote osseointegration in in vivo studies. For the first time to our knowledge, in this study we investigated the resistance of adhesion sequences to proteolytic digestion: HVP was completely cleaved after 5 h. In order to overcome the enzymatic degradation of the native peptide under physiological conditions we synthetized three analogues of HVP sequence. A retro-inverted peptide D-2HVP, composed of D amino acids, was completely stable in serum-containing medium. In addition, glass surfaces functionalized with D-2HVP increased human osteoblast adhesion as compared to the native peptide and maintained deposition of calcium. Interestingly, D-2HVP increased expression of IBSP, VTN and SPP1 genes as compared to HVP functionalized surfaces. Total internal reflection fluorescence microscope analysis showed cells with numerous filopodia spread on D-2HVP-functionalized surfaces. Therefore, the D-2HVP sequence is proposed as new osteoblast adhesive peptide with increased bioactivity and high proteolytic resistance.

Osteoblast Differentiation Decreases Hypergravity-Stimulated Release of PGE(sub 2)

Science.gov (United States)

Searby, Nancy D.; Steele, Charles R.; Globus, Ruth K.

2002-01-01

We determined if progressive differentiation of osteoblasts influences their sensitivity to gravitational loading. Osteoblasts were cultured for 4 days (confluent monolayer), 6 days (prenodules), 9 days (nodules) and 19 days (mineralized nodules), then centrifuged at 10 times gravity (g) or 50-g for 3 hours using the NASA Ames 1-ft. Diameter Centrifuge. Stationary controls were placed in an adjacent incubator. Following centrifugation, conditioned media were collected and analyzed for PGE, by ELISA. Microtubules were fluorescently labeled and analyzed by confocal microscopy to determine microtubule network morphology and height. Centrifugation at 10-g reduced microtubule network height by 15% on d4 and 10% on d6, with variable changes in more mature cultures. No major changes in microtubule morphology were observed. PGE(sub 2) release by d4 cultures increased in a dose-dependent fashion (3-fold at 10-g and 6-fold at 50-g relative to controls). D6 cultures produced a 5-fold increase for both 10-g and 50-g. PGE(sub 2) increased only 1.5-fold by d9, and by d19, PGE(sub 2) was not delectable in either the control or hypergravity-stimulated cells. Thus, as osteoblasts differentiate in culture, responsiveness of the microtubule cytoskeleton and the PGE(sub 2) pathway to hypergravity declines.

Measurement of oxygen consumption rate of osteoblasts from ...

African Journals Online (AJOL)

The cells were evaluated through live/dead assay, hematoxylin-eosin (HE) and alkaline phosphatase (ALP) staining. Moreover, Von-Kossa staining and Alizarin Red S staining were carried out for mineralized nodule formation. Following this, the oxygen consumption rates of osteoblasts in the earlier mentioned different ...

Construction of Zn-incorporated multilayer films to promote osteoblasts growth and reduce bacterial adhesion

Energy Technology Data Exchange (ETDEWEB)

Liu, Peng, E-mail: liupeng79@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433 (China); Zhao, Yongchun; Yuan, Zhang [Key Laboratory of Biorheological Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Ding, Hongyan [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huaian, Jiangsu Province 223003 (China); Hu, Yan; Yang, Weihu [Key Laboratory of Biorheological Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Cai, Kaiyong, E-mail: kaiyong_cai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China)

2017-06-01

To improve the biological performance of titanium substrates, a bioactive multilayered structure of chitosan/gelatin pair, containing zinc ions, was constructed via a layer-by-layer self-assembly technique. The successful preparation of zinc ions incorporated multilayer films was demonstrated by scanning electron microscopy, X-ray photoelectron spectroscopy, and contact angle measurements, respectively. The biological behaviors of osteoblasts adhered to modified Ti substrates were investigated in vitro via cytoskeleton observation, cell viability measurement, and alkaline phosphatase activity assay. The cytocompatibility evaluation verified that the present system was capable of promoting the growth of osteoblasts. In addition, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria were used to evaluate antibacterial property of modified Ti substrates. Bacterial adhesion and viability assay confirmed that Zn-loaded multilayer films were able to inhibit the adhesion and growth of bacteria. The approach presented here affords an alternative to reduce bacterial infection and promote osteoblast growth for titanium-based implants. - Highlights: • Polyelectrolyte multilayer films containing Zn ions were fabricated on Ti substrate. • Modified Ti substrate stimulated the biological responses of osteoblast. • Antibacterial property of Ti substrate was significantly improved. • The resulting material thus has potential application in orthopedic field.

Osteoclasts but not osteoblasts are affected by a calcified surface treated with zoledronic acid in vitro

International Nuclear Information System (INIS)

Schindeler, Aaron; Little, David G.

2005-01-01

Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption. Recent interest has centered on the effects of bisphosphonates on osteoblasts. Chronic dosing of osteoblasts with solubilized bisphosphonates has been reported to enhance osteogenesis and mineralization in vitro. However, this methodology poorly reflects the in vivo situation, where free bisphosphonate becomes rapidly bound to mineralized bone surfaces. To establish a more clinically relevant cell culture model, we cultured bone cells on calcium phosphate coated quartz discs pre-treated with the potent nitrogen-containing bisphosphonate, zoledronic acid (ZA). Binding studies utilizing [ 14 C]-labeled ZA confirmed that the bisphosphonate bound in a concentration-dependent manner over the 1-50 μM dose range. When grown on ZA-treated discs, the viability of bone-marrow derived osteoclasts was greatly reduced, while the viability and mineralization of the osteoblastic MC3T3-E1 cell line were largely unaffected. This suggests that only bone resorbing cells are affected by bound bisphosphonate. However, this system does not account for transient exposure to unbound bisphosphonate in the hours following a clinical dosing. To model this event, we transiently treated osteoblasts with ZA in the absence of a calcified surface. Osteoblasts proved highly resistant to all transitory treatment regimes, even when utilizing ZA concentrations that prevented mineralization and/or induced cell death when dosed chronically. This study represents a pharmacologically more relevant approach to modeling bisphosphonate treatment on cultured bone cells and implies that bisphosphonate therapies may not directly affect osteoblasts at bone surfaces

SATB2 participates in regulation of menadione-induced apoptotic insults to osteoblasts.

Science.gov (United States)

Wei, Jyh-Ding; Lin, Yi-Ling; Tsai, Cheng-Hsiu; Shieh, Hui-Shan; Lin, Pei-I; Ho, Wei-Pin; Chen, Ruei-Ming

2012-07-01

Special AT-rich sequence binding protein 2 (SATB2), a nuclear matrix attachment region-binding protein, can regulate embryonic development, cell differentiation, and cell survival. Previous studies showed that SATB2 is involved in osteoblast differentiation and skeletal development. In this study, we evaluated the role of SATB2 in oxidative stress-induced apoptotic insults to human osteoblast-like MG63 cells and mouse MC3T3-E1 cells. Exposure of MG63 cells to menadione increased intracellular reactive oxygen species levels in a concentration- and time-dependent manner. Simultaneously, menadione-induced oxidative stress triggered cell shrinkage and decreased cell viability. In addition, treatment of MG63 cells with menadione time-dependently decreased the mitochondrial membrane potential but enhanced caspase-3 activity. As a result, menadione-induced DNA fragmentation and cell apoptosis. As to the mechanism, exposure of MG63 cells to menadione amplified SATB2 messenger (m)RNA and protein expression in a time-dependent manner. Knockdown of translation of SATB2 mRNA using RNA interference led to chromatin disruption and nuclear damage. When MG63 cells and MC3T3-E1 cells were treated with SATB2 small interfering RNA, menadione-induced cell apoptosis was increased. We conclude that menadione causes oxidative stress in human osteoblasts and induces cellular apoptosis via a mitochondrion-caspase protease pathway. In addition, SATB2 may play a crucial role in protecting against oxidative stress-induced osteoblast apoptosis. Copyright © 2012 Orthopaedic Research Society.

Low-intensity pulsed ultrasound regulates proliferation and differentiation of osteoblasts through osteocytes

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Li, Lei, E-mail: geraldleelei@163.com [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu (China); Yang, Zheng [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu (China); Zhang, Hai [Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA (United States); Chen, Wenchuan [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu (China); Chen, Mengshi [Department of Biomechanics, Sichuan University, Chengdu (China); Zhu, Zhimin, E-mail: hxzhimin@163.com [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu (China)

2012-02-10

Highlights: Black-Right-Pointing-Pointer CM from LIPUS-stimulated osteocytes inhibits proliferation of osteoblasts. Black-Right-Pointing-Pointer CM from LIPUS-stimulated osteocytes enhances differentiation of osteoblasts. Black-Right-Pointing-Pointer LIPUS stimulates MLO-Y4 cells to secrete PGE{sub 2} and NO. -- Abstract: Low-intensity pulsed ultrasound (LIPUS) has been used as a safe and effective modality to enhance fracture healing. As the most abundant cells in bone, osteocytes orchestrate biological activities of effector cells via direct cell-to-cell contacts and by soluble factors. In this study, we have used the osteocytic MLO-Y4 cells to study the effects of conditioned medium from LIPUS-stimulated MLO-Y4 cells on proliferation and differentiation of osteoblastic MC3T3-E1 cells. Conditioned media from LIPUS-stimulated MLO-Y4 cells (LIPUS-Osteocyte-CM) were collected and added on MC3T3-E1 cell cultures. MC3T3-E1 cells cultured in LIPUS-Osteocyte-CM demonstrated a significant inhibition of proliferation and an increased alkaline phosphatase activity. The results of PGE{sub 2} and NO assay showed that LIPUS could enhance PGE{sub 2} and NO secretion from MLO-Y4 cells at all time points within 24 h after LIPUS stimulation. We conclude that LIPUS regulates proliferation and differentiation of osteoblasts through osteocytes in vitro. Increased secretion of PGE{sub 2} from osteocytes may play a role in this effect.

Osteoblasts generate an osteogenic microenvironment when grown on surfaces with rough microtopographies

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Boyan B. D.

2003-10-01

Full Text Available Osteoblasts respond to microarchitectural features of their substrate. On smooth surfaces (tissue culture plastic, tissue culture glass, and titanium, the cells attach and proliferate but they exhibit relatively low expression of differentiation markers in monolayer cultures, even when confluent. When grown on microrough Ti surfaces with an average roughness (Ra of 4-7 µm, proliferation is reduced but differentiation is enhanced and in some cases, is synergistic with the effects of surface microtopography. In addition, cells on microrough Ti substrates form hydroxyapatite in a manner that is more typical of bone than do cells cultured on smooth surfaces. Osteoblasts also respond to growth factors and cytokines in a surface-dependent manner. On rougher surfaces, the effects of regulatory factors like 1alpha,25(OH2D3 or 17beta-estradiol are enhanced. The response to the surface is mediated by integrins, which signal to the cell through many of the same mechanisms used by growth factors and hormones. Studies using PEG-modified surfaces indicate that increased differentiation may be related to altered attachment to the surface. When osteoblasts are grown on surfaces with chemistries or microarchitectures that reduce cell attachment and proliferation, and enhance differentiation, the cells tend to increase production of factors like TGF-beta1 that promote osteogenesis while decreasing osteoclastic activity. Thus, on microrough Ti surface, osteoblasts create a microenvironment conducive to new bone formation.

Effect of fibronectin adsorption on osteoblastic cellular responses to hydroxyapatite and alumina

International Nuclear Information System (INIS)

Kawashita, Masakazu; Hasegawa, Maki; Kudo, Tada-aki; Kanetaka, Hiroyasu; Miyazaki, Toshiki; Hashimoto, Masami

2016-01-01

Initial cellular responses following implantation are important for inducing osteoconduction. We investigated cell adhesion, spreading, proliferation and differentiation of mouse MC3T3-E1 osteoblastic cells on untreated or fibronectin (Fn)-coated discs of hydroxyapatite (HAp) or alpha-type alumina (α-Al 2 O 3 ). Fn coating significantly enhanced adhesion and spreading of MC3T3-E1 cells on HAp, but did not affect MC3T3-E1 cell proliferation and differentiation on HAp or α-Al 2 O 3 . Fn-coated HAp likely does not stimulate pre-osteoblast cells to initiate the process of osteoconduction; however, Fn adsorption might affect the response of inflammatory cells to the implanted material or, in conjunction with other serum proteins, stimulate pre-osteoblast cell proliferation and differentiation. Further studies on the effect of serum proteins in cell culture and the efficacy of Fn-coated HAp and α-Al 2 O 3 in vivo are warranted. - Highlights: • We studied osteoblast-like MC3T3-E1 cell responses on fibronectin (Fn)-coated discs (HAp/α-Al 2 O 3 ). • Fn adsorption enhanced adhesion and spreading of MC3T3-E1 cells on HAp but not on α-Al 2 O 3 . • Fn adsorption hardly affected proliferation and differentiation of MC3T3-E1 cells on HAp and α-Al 2 O 3 . • Fn adsorption might stimulate osteoconduction on HAp along with other serum proteins.

Knockdown of Indian hedgehog protein induces an inhibition of cell growth and differentiation in osteoblast MC3T3-E1 cells

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Deng, Ang; Zhang, Hongqi; Hu, Minyu; Liu, Shaohua; Gao, Qile; Wang, Yuxiang; Guo, Chaofeng

2017-01-01

Indian hedgehog protein (Ihh) is evolutionarily conserved and serves important roles in controlling the differentiation of progenitor cells into osteoblasts. Ihh null mutant mice exhibit a failure of osteoblast development in endochondral bone. Although studies have demonstrated that Ihh signaling is a potent local factor that regulates osteoblast differentiation, the specific transcription factors that determine osteoblast differentiation remain unclear. Further studies are required to deter...

Transduction of Oct6 or Oct9 gene concomitant with Myc family gene induced osteoblast-like phenotypic conversion in normal human fibroblasts

International Nuclear Information System (INIS)

Mizoshiri, N.; Kishida, T.; Yamamoto, K.; Shirai, T.; Terauchi, R.; Tsuchida, S.; Mori, Y.; Ejima, A.; Sato, Y.; Arai, Y.; Fujiwara, H.; Yamamoto, T.; Kanamura, N.; Mazda, O.; Kubo, T.

2015-01-01

Introduction: Osteoblasts play essential roles in bone formation and regeneration, while they have low proliferation potential. Recently we established a procedure to directly convert human fibroblasts into osteoblasts (dOBs). Transduction of Runx2 (R), Osterix (X), Oct3/4 (O) and L-myc (L) genes followed by culturing under osteogenic conditions induced normal human fibroblasts to express osteoblast-specific genes and produce calcified bone matrix both in vitro and in vivo Intriguingly, a combination of only two factors, Oct3/4 and L-myc, significantly induced osteoblast-like phenotype in fibroblasts, but the mechanisms underlying the direct conversion remains to be unveiled. Materials and Methods: We examined which Oct family genes and Myc family genes are capable of inducing osteoblast-like phenotypic conversion. Results: As result Oct3/4, Oct6 and Oct9, among other Oct family members, had the capability, while N-myc was the most effective Myc family gene. The Oct9 plus N-myc was the best combination to induce direct conversion of human fibroblasts into osteoblast-like cells. Discussion: The present findings may greatly contribute to the elucidation of the roles of the Oct and Myc proteins in osteoblast direct reprogramming. The results may also lead to establishment of novel regenerative therapy for various bone resorption diseases. - Highlights: • Introducing L-myc in a combination with either Oct3/4, Oct6 or Oct9 enables the conversion of fibroblasts to osteoblasts. • A combination of L-myc with Oct3/4 or Oct9 can induce the cells to a phenotype closer to normal osteoblasts. • N-myc was considered the most appropriate Myc family gene for induction of osteoblast-like phenotype in fibroblasts. • The combination of Oct9 plus N-myc has the strongest capability of inducing osteoblast-like phenotype.

Transduction of Oct6 or Oct9 gene concomitant with Myc family gene induced osteoblast-like phenotypic conversion in normal human fibroblasts

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Mizoshiri, N. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Kishida, T. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Yamamoto, K. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Dental Medicine, Kyoto Prefectural University of Medicine, Kyoto (Japan); Shirai, T.; Terauchi, R.; Tsuchida, S. [Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Mori, Y. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Ejima, A. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Sato, Y. [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Department of Dental Medicine, Kyoto Prefectural University of Medicine, Kyoto (Japan); Arai, Y.; Fujiwara, H. [Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan); Yamamoto, T.; Kanamura, N. [Department of Dental Medicine, Kyoto Prefectural University of Medicine, Kyoto (Japan); Mazda, O., E-mail: mazda@koto.kpu-m.ac.jp [Department of Immunology, Kyoto Prefectural University of Medicine, Kyoto (Japan); Kubo, T. [Department of Orthopaedics, Kyoto Prefectural University of Medicine, Kyoto (Japan)

2015-11-27

Introduction: Osteoblasts play essential roles in bone formation and regeneration, while they have low proliferation potential. Recently we established a procedure to directly convert human fibroblasts into osteoblasts (dOBs). Transduction of Runx2 (R), Osterix (X), Oct3/4 (O) and L-myc (L) genes followed by culturing under osteogenic conditions induced normal human fibroblasts to express osteoblast-specific genes and produce calcified bone matrix both in vitro and in vivo Intriguingly, a combination of only two factors, Oct3/4 and L-myc, significantly induced osteoblast-like phenotype in fibroblasts, but the mechanisms underlying the direct conversion remains to be unveiled. Materials and Methods: We examined which Oct family genes and Myc family genes are capable of inducing osteoblast-like phenotypic conversion. Results: As result Oct3/4, Oct6 and Oct9, among other Oct family members, had the capability, while N-myc was the most effective Myc family gene. The Oct9 plus N-myc was the best combination to induce direct conversion of human fibroblasts into osteoblast-like cells. Discussion: The present findings may greatly contribute to the elucidation of the roles of the Oct and Myc proteins in osteoblast direct reprogramming. The results may also lead to establishment of novel regenerative therapy for various bone resorption diseases. - Highlights: • Introducing L-myc in a combination with either Oct3/4, Oct6 or Oct9 enables the conversion of fibroblasts to osteoblasts. • A combination of L-myc with Oct3/4 or Oct9 can induce the cells to a phenotype closer to normal osteoblasts. • N-myc was considered the most appropriate Myc family gene for induction of osteoblast-like phenotype in fibroblasts. • The combination of Oct9 plus N-myc has the strongest capability of inducing osteoblast-like phenotype.

Hypergravity Stimulates the Extracellular Matrix/Integrin-Signaling Axis and Proliferation in Primary Osteoblasts

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Parra, M.; Vercoutere, W.; Roden, C.; Banerjee, I.; Krauser, W.; Holton, E.; Searby, N.; Globus, R.; Almeida, E.

2003-01-01

We set out to determine the molecular mechanisms involved in the proliferative response of primary rat osteoblasts to mechanical stimulation using cell culture centrifugation as a model for hypergravity. We hypothesized that this proliferative response is mediated by specific integrin/Extracellular Matrix (ECM) interactions. To investigate this question we developed a cell culture centrifuge and an automated system that performs cell fixation during hypergravity loading. We generated expression vectors for various focal adhesion and cytoskeletal proteins fused to GFP or dsRed and visualized these structures in transfected (or infected) osteoblasts. The actin cytoskeleton was also visualized using rhodamine-phalloidin staining and Focal Adhesion Kinase (FAK) levels were assessed biochemically. We observed that a 24 hour exposure to 50-g stimulated proliferation compared to the 1-g control when cells were plated on fibronectin, collagen Type I , and collagen Type IV, but not on uncoated tissue culture plastic surfaces. This proliferative response was greatest for osteoblasts grown on fibronectin (2-fold increase over 1-g control) and collagen Type I (1.4 fold increase over 1-g control), suggesting that specific matrices and integrins are involved in the signaling pathways required for proliferation. Exposing osteoblasts grown on different matrices to 10-g or 25-g showed that effects on proliferation depended on both matrix type and loading level. We found that osteoblasts exposed to a short pulse of hypergravity during adhesion spread further and had more GFP-FAK containing focal adhesions compared to their 1-g controls. While overall levels of FAK did not change, more FAK was in the active (phosphorylated) form under hypergravity than in the 1-g controls. Cytoskeletal F-actin organization into filaments was also more prominent after brief exposures to hypergravity during the first five minutes of adhesion. These results suggest that specific integrins sense

Osteogenic differentiation of mesenchymal stem cells is regulated by osteocyte and osteoblast cells in a simplified bone niche

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LM McNamara

2012-01-01

Full Text Available Mesenchymal stem cells (MSCs within their native environment of the stem cell niche in bone receive biochemical stimuli from surrounding cells. These stimuli likely influence how MSCs differentiate to become bone precursors. The ability of MSCs to undergo osteogenic differentiation is well established in vitro;however, the role of the natural cues from bone’s regulatory cells, osteocytes and osteoblasts in regulating the osteogenic differentiation of MSCs in vivo are unclear. In this study we delineate the role of biochemical signalling from osteocytes and osteoblasts, using conditioned media and co-culture experiments, to understand how they direct osteogenic differentiation of MSCs. Furthermore, the synergistic relationship between osteocytes and osteoblasts is examined by transwell co-culturing of MSCs with both simultaneously. Osteogenic differentiation of MSCs was quantified by monitoring alkaline phosphatase (ALP activity, calcium deposition and cell number. Intracellular ALP was found to peak earlier and there was greater calcium deposition when MSCs were co-cultured with osteocytes rather than osteoblasts, suggesting that osteocytes are more influential than osteoblasts in stimulating osteogenesis in MSCs. Osteoblasts initially stimulated an increase in the number of MSCs, but ultimately regulated MSC differentiation down the same pathway. Our novel co-culture system confirmed a synergistic relationship between osteocytes and osteoblasts in producing biochemical signals to stimulate the osteogenic differentiation of MSCs. This study provides important insights into the mechanisms at work within the native stem cell niche to stimulate osteogenic differentiation and outlines a possible role for the use of co-culture or conditioned media methodologies for tissue engineering applications.

Wnt/β-catenin signaling activates nephronectin expression in osteoblasts

International Nuclear Information System (INIS)

Ikehata, Mikiko; Yamada, Atsushi; Morimura, Naoko; Itose, Masakatsu; Suzawa, Tetsuo; Shirota, Tatsuo; Chikazu, Daichi; Kamijo, Ryutaro

2017-01-01

Nephronectin (Npnt), an extracellular matrix protein, is considered to play critical roles as an adhesion molecule in the development and functions of various organs and tissues, such as the kidneys and bone. In the present study, we found that Wnt3a strongly enhanced Npnt mRNA expression in osteoblast-like MC3T3-E1 cells, while it also induced an increase in Npnt gene expression in both time- and dose-dependent manners via the Wnt/β-catenin signaling pathway. These results suggest novel mechanisms for Wnt3a-induced osteoblast proliferation and cell survival via Npnt gene expression. - Highlights: • Wnt3a enhances nephronectin gene expression. • Nephronectin gene induction by Wnt3a is occurred by time- and dose-dependent manner. • Expression of nephronectin is regulated via β-catenin activation.

Lithium doped calcium phosphate cement maintains physical mechanical properties and promotes osteoblast proliferation and differentiation.

Science.gov (United States)

Li, Li; Wang, Renchong; Li, Baichuan; Liang, Wei; Pan, Haobo; Cui, Xu; Tang, Jingli; Li, Bing

2017-07-01

Calcium phosphate cement (CPC) has been widely used in bone tissue repairing due to its physical mechanical properties and biocompatibility. Addition of trace element to CPC has shown promising evidence to improve the physical properties and biological activities of CPC. Lithium (Li) has effect on osteoblast proliferation and differentiation. In this study, we incorporated Li to CPC and examined the physical properties of Li/CPC and its effect on osteoblast proliferation and differentiation. We found that Li doped CPC maintained similar setting time, pore size distribution, compressive strength, composition, and morphology as CPC without Li. Additionally, Li doped CPC improved osteoblast proliferation and differentiation significantly compared to CPC without Li. To our knowledge, our results, for the first time, show that Li doped CPC has beneficial effect on osteoblast in cell culture while keeps the excellent physical-mechanical properties of CPC. This study will lead to potential application of Li doped CPC in bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 944-952, 2017. © 2016 Wiley Periodicals, Inc.

Stepwise Differentiation of Pluripotent Stem Cells into Osteoblasts Using Four Small Molecules under Serum-free and Feeder-free Conditions

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Kosuke Kanke

2014-06-01

Full Text Available Pluripotent stem cells are a promising tool for mechanistic studies of tissue development, drug screening, and cell-based therapies. Here, we report an effective and mass-producing strategy for the stepwise differentiation of mouse embryonic stem cells (mESCs and mouse and human induced pluripotent stem cells (miPSCs and hiPSCs, respectively into osteoblasts using four small molecules (CHIR99021 [CHIR], cyclopamine [Cyc], smoothened agonist [SAG], and a helioxanthin-derivative 4-(4-methoxyphenylpyrido[4′,3′:4,5]thieno[2,3-b]pyridine-2-carboxamide [TH] under serum-free and feeder-free conditions. The strategy, which consists of mesoderm induction, osteoblast induction, and osteoblast maturation phases, significantly induced expressions of osteoblast-related genes and proteins in mESCs, miPSCs, and hiPSCs. In addition, when mESCs defective in runt-related transcription factor 2 (Runx2, a master regulator of osteogenesis, were cultured by the strategy, they molecularly recapitulated osteoblast phenotypes of Runx2 null mice. The present strategy will be a platform for biological and pathological studies of osteoblast development, screening of bone-augmentation drugs, and skeletal regeneration.

Influence of radiation on initial attachment of osteoblast-like cells on titanium plate

International Nuclear Information System (INIS)

Kakuta, Saburo; Hamazaki, Miki; Mitsumoto, Kazuyo; Itabashi, Yuto; Fujimori, Shinya; Miyazaki, Takashi; Nagumo, Masao

1996-01-01

Radiotherapy is a useful and convenient therapy for oral cancer. However, there are many side effects such as stomatitis and radionecrosis of jaws. Radionecrosis may cause loosing or infection of biomaterials used for reconstruction of jaws. In this experiment, in vitro investigation was performed to clarify the influence of radiation on initial attachment of osteoblast-like cells to the titanium plate. UMR-106 and MC3T3-E1 cells were used as osteoblast-like cells. Cell attachment was evaluated by alkaline phosphatase activity and staining attached cells with crystal violet. The results revealed that initial attachment of osteoblast-like cells to the titanium plate was dose-dependently decreased by radiation and that radiosensitivity of each cell was different respectively. Furthermore, the participation of active oxygen was suggested because of partial recovery of cell attachment by addition of superoxide dismutase and/or an antioxidant such as ascorbic acid. (author)

The roles of P2Y2 purinergic receptors in osteoblasts and mechanotransduction.

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Yanghui Xing

Full Text Available We previously demonstrated, using osteoblastic MC3T3-E1 cells, that P2Y2 purinergic receptors are involved in osteoblast mechanotransduction. In this study, our objective was to further investigate, using a knockout mouse model, the roles of P2Y2 receptors in bone mechanobiology. We first examined bone structure with micro-CT and measured bone mechanical properties with three point bending experiments in both wild type mice and P2Y2 knockout mice. We found that bones from P2Y2 knockout mice have significantly decreased bone volume, bone thickness, bone stiffness and bone ultimate breaking force at 17 week old age. In order to elucidate the mechanisms by which P2Y2 receptors contribute to bone biology, we examined differentiation and mineralization of bone marrow cells from wild type and P2Y2 knockout mice. We found that P2Y2 receptor deficiency reduces the differentiation and mineralization of bone marrow cells. Next, we compared the response of primary osteoblasts, from both wild type and P2Y2 knockout mice, to ATP and mechanical stimulation (oscillatory fluid flow, and found that osteoblasts from wild type mice have a stronger response, in terms of ERK1/2 phosphorylation, to both ATP and fluid flow, relative to P2Y2 knockout mice. However, we did not detect any difference in ATP release in response to fluid flow between wild type and P2Y2 knock out osteoblasts. Our findings suggest that P2Y2 receptors play important roles in bone marrow cell differentiation and mineralization as well as in bone cell mechanotransduction, leading to an osteopenic phenotype in P2Y2 knockout mice.

Behaviour of moderately differentiated osteoblast-like cells cultured in contact with bioactive glasses

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Hattar S.

2002-12-01

Full Text Available Bioactive glasses have been shown to stimulate osteogenesis both in vivo and in vitro. However, the molecular mechanisms underlying this process are still poorly understood. In this study, we have investigated the behaviour of osteoblast-like cells (MG63, cultured in the presence of bioglass particles. Three types of granules were used: 45S5registered bioactive glass, 45S5registered granules preincubated in tris buffer and 60S non-reactive glass, used as control. Phase contrast microscopy permitted step-by-step visualization of cell cultures in contact with the particles. Ultrastructural observations of undecalcified sections revealed direct contacts of the cells and an electron-dense layer located at the periphery of the material. Protein synthesis was evaluated biochemically and showed a gradual increase throughout the culture time in the three types of cultures. Alkaline phosphatase was detected in situ, in clusters of packed cells either in contact with the material or in the background cell layer. Semi-quantitative RT-PCR analysis of the main osteoblastic markers showed that gene expression was maintained in all three cultures. The fact that osteocalcin was not detected, supports the fact that the MG63 cell line is composed of less differentiated osteogenic cells rather than mature osteoblasts. We also demonstrated for the first time in this cell line, the expression of Msx-2, Dlx-3 and Dlx-7 homeogenes, known to regulate in vivo foetal skeletogenesis as well as adult skeletal regeneration. However, no significant differences could be recognised in the expression pattern of bone markers between the three types of cultures. Yet these preliminary results indicate that bioactive glasses provided a suitable environment for the growth and proliferation of osteoblasts in vitro, since no drastic changes in phenotype expression of pre-osteoblasts was noted.

Real-time observations of mechanical stimulus-induced enhancements of mechanical properties in osteoblast cells

International Nuclear Information System (INIS)

Zhang Xu; Liu Xiaoli; Sun Jialun; He Shuojie; Lee, Imshik; Pak, Hyuk Kyu

2008-01-01

Osteoblast, playing a key role in the pathophysiology of osteoporosis, is one of the mechanical stress sensitive cells. The effects of mechanical load-induced changes of mechanical properties in osteoblast cells were studied at real-time. Osteoblasts obtained from young Wister rats were exposed to mechanical loads in different frequencies and resting intervals generated by atomic force microscopy (AFM) probe tip and simultaneously measured the changes of the mechanical properties by AFM. The enhancement of the mechanical properties was observed and quantified by the increment of the apparent Young's modulus, E * . The observed mechanical property depended on the frequency of applied tapping loads. For the resting interval is 50 s, the mechanical load-induced enhancement of E * -values disappears. It seems that the enhanced mechanical property was recover able under no additional mechanical stimulus

Bone marrow-derived osteoblast progenitor cells in circulating blood contribute to ectopic bone formation in mice

International Nuclear Information System (INIS)

Otsuru, Satoru; Tamai, Katsuto; Yamazaki, Takehiko; Yoshikawa, Hideki; Kaneda, Yasufumi

2007-01-01

Recent studies have suggested the existence of osteoblastic cells in the circulation, but the origin and role of these cells in vivo are not clear. Here, we examined how these cells contribute to osteogenesis in a bone morphogenetic protein (BMP)-induced model of ectopic bone formation. Following lethal dose-irradiation and subsequent green fluorescent protein-transgenic bone marrow cell-transplantation (GFP-BMT) in mice, a BMP-2-containing collagen pellet was implanted into muscle. Three weeks later, a significant number of GFP-positive osteoblastic cells were present in the newly generated ectopic bone. Moreover, peripheral blood mononuclear cells (PBMNCs) from the BMP-2-implanted mouse were then shown to include osteoblast progenitor cells (OPCs) in culture. Passive transfer of the PBMNCs isolated from the BMP-2-implanted GFP-mouse to the BMP-2-implanted nude mouse led to GFP-positive osteoblast accumulation in the ectopic bone. These data provide new insight into the mechanism of ectopic bone formation involving bone marrow-derived OPCs in circulating blood

Histone Deacetylase Inhibition Promotes Osteoblast Maturation by Altering the Histone H4 Epigenome and Reduces Akt Phosphorylation*

Science.gov (United States)

Dudakovic, Amel; Evans, Jared M.; Li, Ying; Middha, Sumit; McGee-Lawrence, Meghan E.; van Wijnen, Andre J.; Westendorf, Jennifer J.

2013-01-01

Bone has remarkable regenerative capacity, but this ability diminishes during aging. Histone deacetylase inhibitors (HDIs) promote terminal osteoblast differentiation and extracellular matrix production in culture. The epigenetic events altered by HDIs in osteoblasts may hold clues for the development of new anabolic treatments for osteoporosis and other conditions of low bone mass. To assess how HDIs affect the epigenome of committed osteoblasts, MC3T3 cells were treated with suberoylanilide hydroxamic acid (SAHA) and subjected to microarray gene expression profiling and high-throughput ChIP-Seq analysis. As expected, SAHA induced differentiation and matrix calcification of osteoblasts in vitro. ChIP-Seq analysis revealed that SAHA increased histone H4 acetylation genome-wide and in differentially regulated genes, except for the 500 bp upstream of transcriptional start sites. Pathway analysis indicated that SAHA increased the expression of insulin signaling modulators, including Slc9a3r1. SAHA decreased phosphorylation of insulin receptor β, Akt, and the Akt substrate FoxO1, resulting in FoxO1 stabilization. Thus, SAHA induces genome-wide H4 acetylation and modulates the insulin/Akt/FoxO1 signaling axis, whereas it promotes terminal osteoblast differentiation in vitro. PMID:23940046

Induction of osteoblast differentiation by selective activation of kinase-mediated actions of the estrogen receptor.

Science.gov (United States)

Kousteni, Stavroula; Almeida, Maria; Han, Li; Bellido, Teresita; Jilka, Robert L; Manolagas, Stavros C

2007-02-01

Estrogens control gene transcription by cis or trans interactions of the estrogen receptor (ER) with target DNA or via the activation of cytoplasmic kinases. We report that selective activation of kinase-mediated actions of the ER with 4-estren-3alpha,17beta-diol (estren) or an estradiol-dendrimer conjugate, each a synthetic compound that stimulates kinase-mediated ER actions 1,000 to 10,000 times more potently than direct DNA interactions, induced osteoblastic differentiation in established cell lines of uncommitted osteoblast precursors and primary cultures of osteoblast progenitors by stimulating Wnt and BMP-2 signaling in a kinase-dependent manner. In sharp contrast, 17beta-estradiol (E(2)) suppressed BMP-2-induced osteoblast progenitor commitment and differentiation. Consistent with the in vitro findings, estren, but not E(2), stimulated Wnt/beta-catenin-mediated transcription in T-cell factor-lacZ transgenic mice. Moreover, E(2) stimulated BMP signaling in mice in which ERalpha lacks DNA binding activity and classical estrogen response element-mediated transcription (ERalpha(NERKI/-)) but not in wild-type controls. This evidence reveals for the first time the existence of a large signalosome in which inputs from the ER, kinases, bone morphogenetic proteins, and Wnt signaling converge to induce differentiation of osteoblast precursors. ER can either induce it or repress it, depending on whether the activating ligand (and presumably the resulting conformation of the receptor protein) precludes or accommodates ERE-mediated transcription.

CBFA1 and topoisomerase I mRNA levels decline during cellular aging of human trabecular osteoblasts

DEFF Research Database (Denmark)

Christiansen, Mette; Kveiborg, M.; Kassem, M.

2000-01-01

In order to understand the reasons for age-related impairment of the function of bone forming osteoblasts, we have examined the steady-state mRNA levels of the transcription factor CBFA1 and topoisomerase I during cellular aging of normal human trabecular osteoblasts, by the use of semiquantitati...

Melatonin regulates CRE-dependent gene transcription underlying osteoblast proliferation by activating Src and PKA in parallel.

Science.gov (United States)

Tao, Lin; Zhu, Yue

2018-01-01

Several studies have indicated a relationship between melatonin and idiopathic scoliosis, including our previous work which demonstrated that melatonin can inhibit osteoblast proliferation; however, the mechanism remains unclear. Here, we utilized a MTT assay to show that melatonin significantly reduces osteoblast proliferation in a concentration-and time-dependent manner. Through a combination of techniques, including real-time PCR, MTT assays, immunofluorescence, and luciferase assays, we confirmed that melatonin-induced changes in phosphorylated cAMP response element-binding protein (CREB) reduced transcriptional activity in a melatonin receptor-dependent manner. Surprisingly, treatment of osteoblasts with the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) inhibitor PD98059 up-regulated other cascades upstream of CREB. We next treated cells with PKA and Src inhibitors and observed that melatonin can also activate the protein kinase A (PKA) and Src pathways. To examine whether Src is upstream from the cAMP-PKA pathway, we measured cAMP levels in response to melatonin with and without a Src inhibitor (PP2) and found that PP2 had no additional effect. Therefore, the transcription-dependent mechanisms involved in CREB phosphorylation, along with melatonin, activated Src via a parallel signaling pathway that was separate from that of PKA. Finally, we transfected osteoblasts with lentiviral CREB short hairpin (sh) RNAs and found a decrease in the expression of proliferating cell nuclear antigen (PCNA) and osteoblast proliferation. These results suggest that CREB and PCNA are downstream targets of melatonin signaling, and that the down-regulation of CREB, which is regulated via PKA and Src pathways, contributes to the melatonin-induced inhibition of osteoblast proliferation.

Feeding blueberry diets in early life prevent senescence of osteoblasts and bone loss in ovariectomized adult female rats.

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Jian Zhang

Full Text Available Appropriate nutrition during early development is essential for maximal bone mass accretion; however, linkage between early nutrition, childhood bone mass, peak bone mass in adulthood, and prevention of bone loss later in life has not been studied.In this report, we show that feeding a high quality diet supplemented with blueberries (BB to pre-pubertal rats throughout development or only between postnatal day 20 (PND20 and PND34 prevented ovariectomy (OVX-induced bone loss in adult life. This protective effect of BB is due to suppression of osteoblastic cell senescence associated with acute loss of myosin expression after OVX. Early exposure of pre-osteoblasts to serum from BB-fed rats was found to consistently increase myosin expression. This led to maintenance osteoblastic cell development and differentiation and delay of cellular entrance into senescence through regulation of the Runx2 gene. High bone turnover after OVX results in insufficient collagenous matrix support for new osteoblasts and their precursors to express myosin and other cytoskeletal elements required for osteoblast activity and differentiation.These results indicate: 1 a significant prevention of OVX-induced bone loss from adult rats can occur with only 14 days consumption of a BB-containing diet immediately prior to puberty; and 2 the molecular mechanisms underlying these effects involves increased myosin production which stimulates osteoblast differentiation and reduces mesenchymal stromal cell senescence.

Effect of fibronectin adsorption on osteoblastic cellular responses to hydroxyapatite and alumina

Energy Technology Data Exchange (ETDEWEB)

Kawashita, Masakazu, E-mail: m-kawa@ecei.tohoku.ac.jp [Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579 (Japan); Hasegawa, Maki [Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8579 (Japan); Kudo, Tada-aki; Kanetaka, Hiroyasu [Graduate School of Dentistry, Tohoku University, Sendai 980-8575 (Japan); Miyazaki, Toshiki [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu 808-0196 (Japan); Hashimoto, Masami [Japan Fine Ceramics Center, Nagoya 456-8587 (Japan)

2016-12-01

Initial cellular responses following implantation are important for inducing osteoconduction. We investigated cell adhesion, spreading, proliferation and differentiation of mouse MC3T3-E1 osteoblastic cells on untreated or fibronectin (Fn)-coated discs of hydroxyapatite (HAp) or alpha-type alumina (α-Al{sub 2}O{sub 3}). Fn coating significantly enhanced adhesion and spreading of MC3T3-E1 cells on HAp, but did not affect MC3T3-E1 cell proliferation and differentiation on HAp or α-Al{sub 2}O{sub 3}. Fn-coated HAp likely does not stimulate pre-osteoblast cells to initiate the process of osteoconduction; however, Fn adsorption might affect the response of inflammatory cells to the implanted material or, in conjunction with other serum proteins, stimulate pre-osteoblast cell proliferation and differentiation. Further studies on the effect of serum proteins in cell culture and the efficacy of Fn-coated HAp and α-Al{sub 2}O{sub 3}in vivo are warranted. - Highlights: • We studied osteoblast-like MC3T3-E1 cell responses on fibronectin (Fn)-coated discs (HAp/α-Al{sub 2}O{sub 3}). • Fn adsorption enhanced adhesion and spreading of MC3T3-E1 cells on HAp but not on α-Al{sub 2}O{sub 3}. • Fn adsorption hardly affected proliferation and differentiation of MC3T3-E1 cells on HAp and α-Al{sub 2}O{sub 3}. • Fn adsorption might stimulate osteoconduction on HAp along with other serum proteins.

Effect of porous titanium coating thickness on in vitro osteoblast phenotype expression

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Antonio Canabarro

2011-03-01

Full Text Available Aim: This study aimed at determining the effect of different thickness of porous titanium (Ti coating, 0.5, 1.0 and 1.5 mm thick (PC-0.5, PC-1.0 and PC-1.5, on osteoblast phenotype expression. Materials and methods: Dense Ti discs coated with 0.5, 1.0 and 1.5 mm of porous Ti (PC-0.5, PC-1.0 and PC-1.5, respectively were fabricated by powder metallurgy process with pore size typically between 50 and 400 μm and porosity of 60%. Osteoblastic cells obtained from human alveolar bone were cultured on dense Ti (D-Ti and PC-Ti discs for periods of up to 17 days. Results: Cultures grown on PC-Ti exhibited higher cell proliferation rate than on D-Ti. By comparing PC-Ti groups, it was observed statistical differences on culture grown only at day 10 (PC-0.5osteoblastic cell proliferation. In addition, they increased gene expression of osteoblastic markers and higher content of mineralized matrix was observed on the thicker PC-Ti coating (PC-1.5. Therefore, further in vivo evaluations should be done in order to investigate whether this structure should be considered for clinical implant applications.

Improving the Osteoblast Cell Adhesion on Electron Beam Controlled TiO2 Nanotubes

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Sung Wook Yoon

2014-01-01

Full Text Available Here we investigate the osteogenesis and synostosis processes on the surface-modified TiO2 nanotubes via electron beam irradiation. The TiO2 nanotubes studied were synthesized by anodization process under different anodizing voltage. For the anodization voltage of 15, 20, and 25 V, TiO2 nanotubes with diameters of 59, 82, and 105 nm and length of 115, 276, and 310 nm were obtained, respectively. MC3T3-E1 osteoblast cell line was incubated on the TiO2 nanotubes to monitor the change in the cell adhesion before and after the electron beam irradiation. We observe that the electron beam irradiation affects the number of surviving osteoblast cells as well as the cultivation time. In particular, the high adhesion rate of 155% was obtained when the osteoblast cells were cultivated for 2 hours on the TiO2 nanotube, anodized under 20 V, and irradiated with 5,000 kGy of electron beam.

Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function

DEFF Research Database (Denmark)

Furlan, Federico; Galbiati, Clara; Jørgensen, Niklas R

2007-01-01

PAR and produce urokinase (uPA). The purpose of this study was to investigate the role of uPAR in bone remodeling. MATERIALS AND METHODS: In vivo studies were performed in uPAR knockout (KO) and wildtype (WT) mice on a C57Bl6/SV129 (75:25) background. Bone mass was analyzed by pQCT. Excised tibias were subjected......The uPAR and its ligand uPA are expressed by both osteoblasts and osteoclasts. Their function in bone remodeling is unknown. We report that uPAR-lacking mice display increased BMD, increased osteogenic potential of osteoblasts, decreased osteoclasts formation, and altered cytoskeletal...... of macrophage-colony stimulating factor (M-CSF) and RANKL. Phalloidin staining in osteoclasts served to study actin ring and podosome formation. RESULTS: pQCT revealed increased bone mass in uPAR-null mice. Mechanical tests showed reduced load-sustaining capability in uPAR KO tibias. uPAR KO osteoblasts showed...

Substrate Stiffness Controls Osteoblastic and Chondrocytic Differentiation of Mesenchymal Stem Cells without Exogenous Stimuli.

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Rene Olivares-Navarrete

Full Text Available Stem cell fate has been linked to the mechanical properties of their underlying substrate, affecting mechanoreceptors and ultimately leading to downstream biological response. Studies have used polymers to mimic the stiffness of extracellular matrix as well as of individual tissues and shown mesenchymal stem cells (MSCs could be directed along specific lineages. In this study, we examined the role of stiffness in MSC differentiation to two closely related cell phenotypes: osteoblast and chondrocyte. We prepared four methyl acrylate/methyl methacrylate (MA/MMA polymer surfaces with elastic moduli ranging from 0.1 MPa to 310 MPa by altering monomer concentration. MSCs were cultured in media without exogenous growth factors and their biological responses were compared to committed chondrocytes and osteoblasts. Both chondrogenic and osteogenic markers were elevated when MSCs were grown on substrates with stiffness <10 MPa. Like chondrocytes, MSCs on lower stiffness substrates showed elevated expression of ACAN, SOX9, and COL2 and proteoglycan content; COMP was elevated in MSCs but reduced in chondrocytes. Substrate stiffness altered levels of RUNX2 mRNA, alkaline phosphatase specific activity, osteocalcin, and osteoprotegerin in osteoblasts, decreasing levels on the least stiff substrate. Expression of integrin subunits α1, α2, α5, αv, β1, and β3 changed in a stiffness- and cell type-dependent manner. Silencing of integrin subunit beta 1 (ITGB1 in MSCs abolished both osteoblastic and chondrogenic differentiation in response to substrate stiffness. Our results suggest that substrate stiffness is an important mediator of osteoblastic and chondrogenic differentiation, and integrin β1 plays a pivotal role in this process.

Mechanisms underlying the attachment and spreading of human osteoblasts: from transient interactions to focal adhesions on vitronectin-grafted bioactive surfaces.

Science.gov (United States)

Brun, Paola; Scorzeto, Michele; Vassanelli, Stefano; Castagliuolo, Ignazio; Palù, Giorgio; Ghezzo, Francesca; Messina, Grazia M L; Iucci, Giovanna; Battaglia, Valentina; Sivolella, Stefano; Bagno, Andrea; Polzonetti, Giovanni; Marletta, Giovanni; Dettin, Monica

2013-04-01

The features of implant devices and the reactions of bone-derived cells to foreign surfaces determine implant success during osseointegration. In an attempt to better understand the mechanisms underlying osteoblasts attachment and spreading, in this study adhesive peptides containing the fibronectin sequence motif for integrin binding (Arg-Gly-Asp, RGD) or mapping the human vitronectin protein (HVP) were grafted on glass and titanium surfaces with or without chemically induced controlled immobilization. As shown by total internal reflection fluorescence microscopy, human osteoblasts develop adhesion patches only on specifically immobilized peptides. Indeed, cells quickly develop focal adhesions on RGD-grafted surfaces, while HVP peptide promotes filopodia, structures involved in cellular spreading. As indicated by immunocytochemistry and quantitative polymerase chain reaction, focal adhesions kinase activation is delayed on HVP peptides with respect to RGD while an osteogenic phenotypic response appears within 24h on osteoblasts cultured on both peptides. Cellular pathways underlying osteoblasts attachment are, however, different. As demonstrated by adhesion blocking assays, integrins are mainly involved in osteoblast adhesion to RGD peptide, while HVP selects osteoblasts for attachment through proteoglycan-mediated interactions. Thus an interfacial layer of an endosseous device grafted with specifically immobilized HVP peptide not only selects the attachment and supports differentiation of osteoblasts but also promotes cellular migration. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Avenanthramides Prevent Osteoblast and Osteocyte Apoptosis and Induce Osteoclast Apoptosis in Vitro in an Nrf2-Independent Manner

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Gretel G. Pellegrini

2016-07-01

Full Text Available Oats contain unique bioactive compounds known as avenanthramides (AVAs with antioxidant properties. AVAs might enhance the endogenous antioxidant cellular response by activation of the transcription factor Nrf2. Accumulation of reactive oxygen species plays a critical role in many chronic and degenerative diseases, including osteoporosis. In this disease, there is an imbalance between bone formation by osteoblasts and bone resorption by osteoclasts, which is accompanied by increased osteoblast/osteocyte apoptosis and decreased osteoclast apoptosis. We investigated the ability of the synthethic AVAs 2c, 2f and 2p, to 1-regulate gene expression in bone cells, 2-affect the viability of osteoblasts, osteocytes and osteoclasts, and the generation of osteoclasts from their precursors, and 3-examine the potential involvement of the transcription factor Nrf2 in these actions. All doses of AVA 2c and 1 and 5 µM dose of 2p up-regulated collagen 1A expression. Lower doses of AVAs up-regulated OPG (osteoprotegerin in OB-6 osteoblastic cells, whereas 100 μM dose of 2f and all concentrations of 2c down-regulated RANKL gene expression in MLO-Y4 osteocytic cells. AVAs did not affect apoptosis of OB-6 osteoblastic cells or MLO-Y4 osteocytic cells; however, they prevented apoptosis induced by the DNA topoisomerase inhibitor etoposide, the glucocorticoid dexamethasone, and hydrogen peroxide. AVAs prevented apoptosis of both wild type (WT and Nrf2 Knockout (KO osteoblasts, demonstrating that AVAs-induced survival does not require Nrf2 expression. Further, KO osteoclast precursors produced more mature osteoclasts than WT; and KO cultures exhibited less apoptotic osteoclasts than WT cultures. Although AVAs did not affect WT osteoclasts, AVA 2p reversed the low apoptosis of KO osteoclasts. These in vitro results demonstrate that AVAs regulate, in part, the function of osteoblasts and osteocytes and prevent osteoblast/osteocyte apoptosis and increase osteoclast

Effects of bioglass powders with and without mesoporous structures on fibroblast and osteoblast responses

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Shih, Chi-Jen, E-mail: cjshih@kmu.edu.tw [Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Lu, Pei-Shan [Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, 100 Shi-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Hsieh, Chih-Hsin [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Chen, Wen-Cheng [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Chen, Jian-Chih [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China)

2014-09-30

Highlights: • Fluorescent microscopy images show that BG-M has excellent cellular affinity. • Both the BG and BG-M substrates had positive effects on the proliferation of the osteoblastic cells. • Cells cultured on BG-M had approximately 1.4 times higher proliferation activity. - Abstract: The main objective of this study was to compare the responses of fibroblasts and osteoblasts to bioglass (BG) and bioglass-containing mesoporous structure (BG-M) powders. The BG-M powders exhibited specific surface areas approximately three times larger than those of the BG powders. The formation of a hysteresis loop also signified the presence of mesoporous structures in the BG-M samples; however, a hysteresis loop was not observed for the BG samples, resulting in 1/5 the pore volume of the BG-M samples. The viabilities of the fibroblasts and osteoblasts cultured in media containing the BG-M powders for 1, 2, and 3 days were greater than 90%. Importantly, the results of fluorescent microscopy images show that BG-M has excellent cellular affinity. Both the BG and BG-M substrates had positive effects on the proliferation of the osteoblastic cells. However, cells cultured on BG-M had approximately 1.4 times higher proliferation activity.

Effects of bioglass powders with and without mesoporous structures on fibroblast and osteoblast responses

International Nuclear Information System (INIS)

Shih, Chi-Jen; Lu, Pei-Shan; Hsieh, Chih-Hsin; Chen, Wen-Cheng; Chen, Jian-Chih

2014-01-01

Highlights: • Fluorescent microscopy images show that BG-M has excellent cellular affinity. • Both the BG and BG-M substrates had positive effects on the proliferation of the osteoblastic cells. • Cells cultured on BG-M had approximately 1.4 times higher proliferation activity. - Abstract: The main objective of this study was to compare the responses of fibroblasts and osteoblasts to bioglass (BG) and bioglass-containing mesoporous structure (BG-M) powders. The BG-M powders exhibited specific surface areas approximately three times larger than those of the BG powders. The formation of a hysteresis loop also signified the presence of mesoporous structures in the BG-M samples; however, a hysteresis loop was not observed for the BG samples, resulting in 1/5 the pore volume of the BG-M samples. The viabilities of the fibroblasts and osteoblasts cultured in media containing the BG-M powders for 1, 2, and 3 days were greater than 90%. Importantly, the results of fluorescent microscopy images show that BG-M has excellent cellular affinity. Both the BG and BG-M substrates had positive effects on the proliferation of the osteoblastic cells. However, cells cultured on BG-M had approximately 1.4 times higher proliferation activity

A 3D printed nano bone matrix for characterization of breast cancer cell and osteoblast interactions

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Zhu, Wei; Castro, Nathan J.; Cui, Haitao; Zhou, Xuan; Boualam, Benchaa; McGrane, Robert; Glazer, Robert I.; Zhang, Lijie Grace

2016-08-01

Bone metastasis is one of the most prevalent complications of late-stage breast cancer, in which the native bone matrix components, including osteoblasts, are intimately involved in tumor progression. The development of a successful in vitro model would greatly facilitate understanding the underlying mechanism of breast cancer bone invasion as well as provide a tool for effective discovery of novel therapeutic strategies. In the current study, we fabricated a series of in vitro bone matrices composed of a polyethylene glycol hydrogel and nanocrystalline hydroxyapatite of varying concentrations to mimic the native bone microenvironment for the investigation of breast cancer bone metastasis. A stereolithography-based three-dimensional (3D) printer was used to fabricate the bone matrices with precisely controlled architecture. The interaction between breast cancer cells and osteoblasts was investigated in the optimized bone matrix. Using a Transwell® system to separate the two cell lines, breast cancer cells inhibited osteoblast proliferation, while osteoblasts stimulated breast cancer cell growth, whereas, both cell lines increased IL-8 secretion. Breast cancer cells co-cultured with osteoblasts within the 3D bone matrix formed multi-cellular spheroids in comparison to two-dimensional monolayers. These findings validate the use of our 3D printed bone matrices as an in vitro metastasis model, and highlights their potential for investigating breast cancer bone metastasis.

Post-transcriptional regulation of osteoblastic platelet-derived growth factor receptor-alpha expression by co-cultured primary endothelial cells

DEFF Research Database (Denmark)

Finkenzeller, Günter; Mehlhorn, Alexander T; Schmal, Hagen

2010-01-01

-alpha downregulation is dependent on time and cell number. This effect was specific to endothelial cells and was not observed when hOBs were co-cultured with human primary chondrocytes or fibroblasts. Likewise, HUVEC-mediated suppression of PDGFR-alpha expression was only seen in hOBs and mesenchymal stem cells......Platelet-derived growth factor receptor (PDGFR) signaling plays an important role in osteoblast function. Inhibition of PDGFR activity leads to a suppression of osteoblast proliferation, whereas mineralized matrix production is enhanced. In previous experiments, we showed that co......-cultivation of human primary endothelial cells and human primary osteoblasts (hOBs) leads to a cell contact-dependent downregulation of PDGFR-alpha expression in the osteoblasts. In this study, we investigated this effect in more detail, revealing that human umbilical vein endothelial cell (HUVEC)-mediated PDGFR...

Secreted Clusterin protein inhibits osteoblast differentiation of bone marrow mesenchymal stem cells by suppressing ERK1/2 signaling pathway.

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Abdallah, Basem M; Alzahrani, Abdullah M; Kassem, Moustapha

2018-05-01

Secreted Clusterin (sCLU, also known as Apolipoprotein J) is an anti-apoptotic glycoprotein involved in the regulation of cell proliferation, lipid transport, extracellular tissue remodeling and apoptosis. sCLU is expressed and secreted by mouse bone marrow-derived skeletal (stromal or mesenchymal) stem cells (mBMSCs), but its functional role in MSC biology is not known. In this study, we demonstrated that Clusterin mRNA expression and protein secretion in conditioned medium increased during adipocyte differentiation and decreased during osteoblast differentiation of mBMSCs. Treatment of mBMSC cultures with recombinant sCLU protein increased cell proliferation and exerted an inhibitory effect on the osteoblast differentiation while stimulated adipocyte differentiation in a dose-dependent manner. siRNA-mediated silencing of Clu expression in mBMSCs reduced adipocyte differentiation and stimulated osteoblast differentiation of mBMSCs. Furthermore, the inhibitory effect of sCLU on the osteoblast differentiation of mBMSCs was mediated by the suppression of extracellular signal-regulated kinase (ERK1/2) phosphorylation. In conclusion, we identified sCLU as a regulator of mBMSCs lineage commitment to osteoblasts versus adipocytes through a mechanism mediated by ERK1/2 signaling. Inhibiting sCLU is a possible therapeutic approach for enhancing osteoblast differentiation and consequently bone formation. Copyright © 2018 Elsevier Inc. All rights reserved.

Expression of osterix Is Regulated by FGF and Wnt/β-Catenin Signalling during Osteoblast Differentiation.

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Katharina Felber

Full Text Available Osteoblast differentiation from mesenchymal cells is regulated by multiple signalling pathways. Here we have analysed the roles of Fibroblast Growth Factor (FGF and canonical Wingless-type MMTV integration site (Wnt/β-Catenin signalling pathways on zebrafish osteogenesis. We have used transgenic and chemical interference approaches to manipulate these pathways and have found that both pathways are required for osteoblast differentiation in vivo. Our analysis of bone markers suggests that these pathways act at the same stage of differentiation to initiate expression of the osteoblast master regulatory gene osterix (osx. We use two independent approaches that suggest that osx is a direct target of these pathways. Firstly, we manipulate signalling and show that osx gene expression responds with similar kinetics to that of known transcriptional targets of the FGF and Wnt pathways. Secondly, we have performed ChIP with transcription factors for both pathways and our data suggest that a genomic region in the first intron of osx mediates transcriptional activation. Based upon these data, we propose that FGF and Wnt/β-Catenin pathways act in part by directing transcription of osx to promote osteoblast differentiation at sites of bone formation.

The impact of doped silicon quantum dots on human osteoblasts

Czech Academy of Sciences Publication Activity Database

Ostrovská, L.; Brož, Antonín; Fučíková, A.; Bělinová, T.; Sugimoto, H.; Kanno, T.; Fujii, M.; Valenta, J.; Kalbáčová, M.H.

2016-01-01

Roč. 6, č. 68 (2016), s. 63403-63413 ISSN 2046-2069 Institutional support: RVO:67985823 Keywords : silicon quantum dots * osteoblasts * cytotoxicity * photoluminiscence bioimaging Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.108, year: 2016

Osteoblast-specific deletion of Pkd2 leads to low-turnover osteopenia and reduced bone marrow adiposity.

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Zhousheng Xiao

Full Text Available Polycystin-1 (Pkd1 interacts with polycystin-2 (Pkd2 to form an interdependent signaling complex. Selective deletion of Pkd1 in the osteoblast lineage reciprocally regulates osteoblastogenesis and adipogenesis. The role of Pkd2 in skeletal development has not been defined. To this end, we conditionally inactivated Pkd2 in mature osteoblasts by crossing Osteocalcin (Oc-Cre;Pkd2+/null mice with floxed Pkd2 (Pkd2flox/flox mice. Oc-Cre;Pkd2flox/null (Pkd2Oc-cKO mice exhibited decreased bone mineral density, trabecular bone volume, cortical thickness, mineral apposition rate and impaired biomechanical properties of bone. Pkd2 deficiency resulted in diminished Runt-related transcription factor 2 (Runx2 expressions in bone and impaired osteoblastic differentiation ex vivo. Expression of osteoblast-related genes, including, Osteocalcin, Osteopontin, Bone sialoprotein (Bsp, Phosphate-regulating gene with homologies to endopeptidases on the X chromosome (Phex, Dentin matrix protein 1 (Dmp1, Sclerostin (Sost, and Fibroblast growth factor 23 (FGF23 were reduced proportionate to the reduction of Pkd2 gene dose in bone of Oc-Cre;Pkd2flox/+ and Oc-Cre;Pkd2flox/null mice. Loss of Pkd2 also resulted in diminished peroxisome proliferator-activated receptor γ (PPARγ expression and reduced bone marrow fat in vivo and reduced adipogenesis in osteoblast culture ex vivo. Transcriptional co-activator with PDZ-binding motif (TAZ and Yes-associated protein (YAP, reciprocally acting as co-activators and co-repressors of Runx2 and PPARγ, were decreased in bone of Oc-Cre;Pkd2flox/null mice. Thus, Pkd1 and Pkd2 have coordinate effects on osteoblast differentiation and opposite effects on adipogenesis, suggesting that Pkd1 and Pkd2 signaling pathways can have independent effects on mesenchymal lineage commitment in bone.

The role of surface microtopography in the modulation of osteoblast differentiation

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JS Hayes

2010-07-01

Full Text Available The osteoinductive and conductive capabilities of commercially pure titanium and its alloys is well documented, as is their ability to provide long-term stability for permanent implantable devices. Fracture fixation in paediatric and trauma patients generally requires transient fixation after which the implant becomes redundant and requires removal. Removal can be complicated due to excessive bony over-growth which is encouraged by the standard micro-rough implant surface. We have shown in vivo that removal related morbidity can be significantly reduced with surface polishing, a technique which reduces the micro-roughness of clinically available materials. However, tissue integration at the bone-implant interface requires activation of key regulatory pathways which influences osteoblastic differentiation and maturation therefore we do not believe this effect to be purely mechanical. To elucidate potential mechanisms by which surface polishing exerts its effect on bone regeneration this study assessed in vitro the effect of surface polishing commercially pure titanium on cell growth, morphology and on the regulation of core binding factor 1, osterix, collagen I, alkaline phosphatase, bone sialoprotein and osteocalcin for primary rat calvarial osteoblasts. Results indicate that polishing differentially influences osteoblast differentiation in a surface dependent manner and that these changes are potentially linked to surface dependent morphology, but not to differences in cell proliferation.

Hypergravity Loading the Cultured Osteoblasts: Modeling and Experimental Analysis of Cellular Morphology and the Cytoskeleton

Science.gov (United States)

Searby, N. D.; Steele, C. R.; Globus, R. K.; Dalton, Bonnie P. (Technical Monitor)

2001-01-01

Bone forming cells, osteoblasts, respond to various mechanical forces, including mechanical strain and fluid-induced shear stress. This study examined whether osteoblasts detect changes in gravity as a mechanical force, as assessed by cellular morphology and dimensions of the cytoskeletal network. We used modeling to evaluate how gravity influences cell morphology given theoretical differences in densities between the surrounding medium, cytoplasm, and nucleus. A mechanical model was built based on analysis of axisymmetric shell structures (Fast4 software) to study the effects of 10 times gravity (10G) on cell height. The model indicated 0.02% decrease in overall cell height when the medium was 10% denser than the nucleus or cytoplasm, 5.9 x 10(exp-5)% decrease when the nucleus was 10% denser than the cytoplasm or medium, and 1.3 x 10(exp-5)% decrease when the cell cytoplasm was 10% denser than the nucleus or medium. To experimentally evaluate the influence of gravity, cultured primary fetal rat osteoblasts were grown to near confluence and centrifuged at 10G for 3 hours. Actin, microtubules, and nuclei were fluorescently labeled and analyzed by confocal microscopy to determine overall microtubule and actin network height. Centrifugation led to an apparent reduction in height of both the microtubule (-16%) and the actin (-20%) networks relative to stationary controls. Thus, both modeling and experiments indicate that hypergravity reduces the height of the osteoblast cell layer and their microtubule and actin networks. This combination of modeling and experimental analyses will help us to better understand the mechanical loading of osteoblasts.

Cord blood-derived macrophage-lineage cells rapidly stimulate osteoblastic maturation in mesenchymal stem cells in a glycoprotein-130 dependent manner.

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Tania J Fernandes

Full Text Available In bone, depletion of osteoclasts reduces bone formation in vivo, as does osteal macrophage depletion. How osteoclasts and macrophages promote the action of bone forming osteoblasts is, however, unclear. Since recruitment and differentiation of multi-potential stromal cells/mesenchymal stem cells (MSC generates new active osteoblasts, we investigated whether human osteoclasts and macrophages (generated from cord blood-derived hematopoietic progenitors induce osteoblastic maturation in adipose tissue-derived MSC. When treated with an osteogenic stimulus (ascorbate, dexamethasone and β-glycerophosphate these MSC form matrix-mineralising, alkaline phosphatase-expressing osteoblastic cells. Cord blood-derived progenitors were treated with macrophage colony stimulating factor (M-CSF to form immature proliferating macrophages, or with M-CSF plus receptor activator of NFκB ligand (RANKL to form osteoclasts; culture medium was conditioned for 3 days by these cells to study their production of osteoblastic factors. Both osteoclast- and macrophage-conditioned medium (CM greatly enhanced MSC osteoblastic differentiation in both the presence and absence of osteogenic medium, evident by increased alkaline phosphatase levels within 4 days and increased mineralisation within 14 days. These CM effects were completely ablated by antibodies blocking gp130 or oncostatin M (OSM, and OSM was detectable in both CM. Recombinant OSM very potently stimulated osteoblastic maturation of these MSC and enhanced bone morphogenetic protein-2 (BMP-2 actions on MSC. To determine the influence of macrophage activation on this OSM-dependent activity, CM was collected from macrophage populations treated with M-CSF plus IL-4 (to induce alternative activation or with GM-CSF, IFNγ and LPS to cause classical activation. CM from IL-4 treated macrophages stimulated osteoblastic maturation in MSC, while CM from classically-activated macrophages did not. Thus, macrophage-lineage cells

Deduction of Novel Genes Potentially Involved in Osteoblasts of Rheumatoid Arthritis Using Next-Generation Sequencing and Bioinformatic Approaches

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Yi-Jen Chen

2017-11-01

Full Text Available The role of osteoblasts in peri-articular bone loss and bone erosion in rheumatoid arthritis (RA has gained much attention, and microRNAs are hypothesized to play critical roles in the regulation of osteoblast function in RA. The aim of this study is to explore novel microRNAs differentially expressed in RA osteoblasts and to identify genes potentially involved in the dysregulated bone homeostasis in RA. RNAs were extracted from cultured normal and RA osteoblasts for sequencing. Using the next generation sequencing and bioinformatics approaches, we identified 35 differentially expressed microRNAs and 13 differentially expressed genes with potential microRNA–mRNA interactions in RA osteoblasts. The 13 candidate genes were involved mainly in cell–matrix adhesion, as classified by the Gene Ontology. Two genes of interest identified from RA osteoblasts, A-kinase anchoring protein 12 (AKAP12 and leucin rich repeat containing 15 (LRRC15, were found to express more consistently in the related RA synovial tissue arrays in the Gene Expression Omnibus database, with the predicted interactions with miR-183-5p and miR-146a-5p, respectively. The Ingenuity Pathway Analysis identified AKAP12 as one of the genes involved in protein kinase A signaling and the function of chemotaxis, interconnecting with molecules related to neovascularization. The findings indicate new candidate genes as the potential indicators in evaluating therapies targeting chemotaxis and neovascularization to control joint destruction in RA.

The In-Vitro Effects of Sea Cucumber (Stichopus sp1 Extract on Human Osteoblast Cell Line

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A Shahrulazua

2013-03-01

Full Text Available Despite its claimed therapeutic effects, the action of sea cucumber (known as gamat in the Malay language on human osteoblast cells is still unknown. We performed in vitro studies utilising extract of Stichopus sp1 (gamat to elucidate its effects on cell viability and functional activity. We found an inverse relationship between gamat concentration and its effect on osteoblast cell viability (p<0.001. Only gamat concentration at 1mg/ml significantly promoted cell viability at day 3 of incubation. There was a trend towards increased osteoblast cell function in the presence of gamat at 5mg/ml and 10mg/ml but this observation was not consistent at different incubation periods.

The predominant mechanism of intercellular calcium wave propagation changes during long-term culture of human osteoblast-like cells

DEFF Research Database (Denmark)

Henriksen, Zanne; Hiken, Jeffrey F; Steinberg, Thomas H

2006-01-01

cells still responded to addition of ATP, but P2Y desensitization did not inhibit ICW propagation. Our data indicate that the relative role of P2Y-mediated and gap junction-mediated ICW changes during osteoblast differentiation in vitro. In less differentiated cells, P2Y-mediated ICW predominate......Intercellular calcium waves (ICW) are calcium transients that spread from cell to cell in response to different stimuli. We previously demonstrated that human osteoblast-like cells in culture propagate ICW in response to mechanical stimulation by two mechanisms. One mechanism involves autocrine...... activation of P2Y receptors, and the other requires gap junctional communication. In the current work we ask whether long-term culture of osteoblast-like cells affects the propagation of ICW by these two mechanisms. Human osteoblast-like cells were isolated from bone marrow. Mechanically induced ICW were...

The increased number of osteoblasts and capillaries in orthodontic tooth movement post-administration of Robusta coffee extract

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H. Herniyati

2017-06-01

Full Text Available Background: The application of orthodontic forces subjects blood capillaries to considerable pressure, resulting in hypoxia on the pressure side. Vascular endothelial growth factor (VEGF, expressed in osteoblasts represents an important mitogen that induces angiogenesis. Osteoblasts and blood capillaries play an important role in bone formation. Robusta coffee contains chlorogenic acid and caffeic acid both of which produce antioxidant effects capable of reducing oxidative stress in osteoblasts. Purpose: The aim of this study was to analyze the effects of Robusta coffee extract on the number of osteoblasts and blood capillaries in orthodontic tooth movement. Methods: This research constituted a laboratory-based experimental study involving the use of sixteen male rodents divided into two groups, namely; control group (C consisting of eight mice given orthodontic mechanical force (OMF and a treatment group (T containing eight mice administered OMF and dried Robusta coffee extract at a dose of 20mg/ 100 g BW. The OMF was performed by installing a ligature wire on the maxillary right first molar and both maxillary incisors. In the following stage, the maxillary right first molar was moved to the mesial using Tension Gauze with a Nickel Titanium Orthodontic closed coil spring. Observation was subsequently undertaken on the 15th day by extracting the maxillary right first and second molar with their periodontal tissues. Thereafter, histological examination was performed using hematoxylin-eosin (HE staining technique to measure the number of osteoblasts and blood capillaries on the mesial and distal periodontal ligaments of the maxillary right first molar. Results: The administration of Robusta coffee extract increases the number of blood capillaries and osteoblasts on both the pressure and tension sides were found to be significantly higher in the T group compared to the C group (p<0,05. Conclusion: Robusta coffee extract increase the number of

SIRT1 is a positive regulator of the master osteoblast transcription factor, RUNX2.

Directory of Open Access Journals (Sweden)

Kayvan Zainabadi

Full Text Available Activation of SIRT1 has previously been shown to protect mice against osteoporosis through yet ill-defined mechanisms. In this study, we outline a role for SIRT1 as a positive regulator of the master osteoblast transcription factor, RUNX2. We find that ex vivo deletion of sirt1 leads to decreased expression of runx2 downstream targets, but not runx2 itself, along with reduced osteoblast differentiation. Reciprocally, treatment with a SIRT1 agonist promotes osteoblast differentiation, as well as the expression of runx2 downstream targets, in a SIRT1-dependent manner. Biochemical and luciferase reporter assays demonstrate that SIRT1 interacts with and promotes the transactivation potential of RUNX2. Intriguingly, mice treated with the SIRT1 agonist, resveratrol, show similar increases in the expression of RUNX2 targets in their calvaria (bone tissue, validating SIRT1 as a physiologically relevant regulator of RUNX2.

Biocompatibility of Poly-ε-caprolactone-hydroxyapatite composite on mouse bone marrow-derived osteoblasts and endothelial cells

Directory of Open Access Journals (Sweden)

Wooley Paul H

2009-02-01

Full Text Available Abstract Background Tissue-engineered bone may be developed by seeding the cells capable of both osteogenesis and vascularization on biocompatible composite scaffolds. The current study investigated the performance of mice bone marrow-derived osteogenic cells and endothelial cells as seeded on hydroxyapatite (HA and poly-ε-caprolactone (PCL composite scaffolds. Methods Mononuclear cells were induced to osteoblasts and endothelial cells respectively, which were defined by the expression of osteocalcin, alkaline phosphatase (ALP, and deposits of calcium-containing crystal for osteoblasts, or by the expression of vascular endothelial growth factor receptor-2 (VEGFR-2 and von Willebrand factor (vWF, and the formation of a capillary network in Matrigel™ for endothelial cells. Both types of cell were seeded respectively on PCL-HA scaffolds at HA to PCL weight ratio of 1:1, 1:4, or 0:1 and were evaluated using scanning electron microscopy, ALP activity (of osteoblasts and nitric oxide production (of endothelial cells plus the assessment of cell viability. Results The results indicated that HA led to a positive stimulation of osteoblasts viability and ALP activity, while HA showed less influence on endothelial cells viability. An elevated nitric oxide production of endothelial cells was observed in HA-containing group. Conclusion Supplement of HA into PCL improved biocompatible for bone marrow-derived osteoblasts and endothelial cells. The PCL-HA composite integrating with two types of cells may provide a useful system for tissue-engineered bone grafts with vascularization.

Tissue transglutaminase (TG2 activity regulates osteoblast differentiation and mineralization in the SAOS-2 cell line

Directory of Open Access Journals (Sweden)

Xiaoxue Yin

2012-08-01

Full Text Available Tissue transglutaminase (type II, TG2 has long been postulated to directly promote skeletal matrix calcification and play an important role in ossification. However, limited information is available on the expression, function and modulating mechanism of TG2 during osteoblast differentiation and mineralization. To address these issues, we cultured the well-established human osteosarcoma cell line SAOS-2 with osteo-inductive conditioned medium and set up three time points (culture days 4, 7, and 14 to represent different stages of SAOS-2 differentiation. Osteoblast markers, mineralization, as well as TG2 expression and activity, were then assayed in each stage. Furthermore, we inhibited TG activity with cystamine and then checked SAOS-2 differentiation and mineralization in each stage. The results showed that during the progression of osteoblast differentiation SAOS-2 cells presented significantly high levels of osteocalcin (OC mRNA, bone morphogenetic protein-2 (BMP-2 and collagen I, significantly high alkaline phosphatase (ALP activity, and the increased formation of calcified matrix. With the same tendency, TG2 expression and activity were up-regulated. Furthermore, inhibition of TG activity resulted in a significant decrease of OC, collagen I, and BMP-2 mRNA and of ALP activity and mineralization. This study demonstrated that TG2 is involved in osteoblast differentiation and may play a role in the initiation and regulation of the mineralization processes. Moreover, the modulating effects of TG2 on osteoblasts may be related to BMP-2.

Myeloma cells suppress osteoblasts through sclerostin secretion

Energy Technology Data Exchange (ETDEWEB)

Colucci, S; Brunetti, G; Oranger, A [Department of Human Anatomy and Histology, University of Bari Medical School, Bari (Italy); Mori, G [Department of Biomedical Science, University of Foggia, Foggia (Italy); Sardone, F [Department of Human Anatomy and Histology, University of Bari Medical School, Bari (Italy); Specchia, G; Rinaldi, E; Curci, P; Liso, V [Department of Emergency and Organ Transplantation, Hematology Section, Bari University Medical School, Bari (Italy); Passeri, G [Department of Internal Medicine and Biomedical Sciences, Center for Metabolic Bone Diseases, University of Parma, Parma (Italy); Zallone, A [Department of Human Anatomy and Histology, University of Bari Medical School, Bari (Italy); Rizzi, R [Department of Emergency and Organ Transplantation, Hematology Section, Bari University Medical School, Bari (Italy); Grano, M [Department of Human Anatomy and Histology, University of Bari Medical School, Bari (Italy)

2011-06-01

Wingless-type (Wnt) signaling through the secretion of Wnt inhibitors Dickkopf1, soluble frizzled-related protein-2 and -3 has a key role in the decreased osteoblast (OB) activity associated with multiple myeloma (MM) bone disease. We provide evidence that another Wnt antagonist, sclerostin, an osteocyte-expressed negative regulator of bone formation, is expressed by myeloma cells, that is, human myeloma cell lines (HMCLs) and plasma cells (CD138+ cells) obtained from the bone marrow (BM) of a large number of MM patients with bone disease. We demonstrated that BM stromal cells (BMSCs), differentiated into OBs and co-cultured with HMCLs showed, compared with BMSCs alone, reduced expression of major osteoblastic-specific proteins, decreased mineralized nodule formation and attenuated the expression of members of the activator protein 1 transcription factor family (Fra-1, Fra-2 and Jun-D). Moreover, in the same co-culture system, the addition of neutralizing anti-sclerostin antibodies restored OB functions by inducing nuclear accumulation of β-catenin. We further demonstrated that the upregulation of receptor activator of nuclear factor κ-B ligand and the downregulation of osteoprotegerin in OBs were also sclerostin mediated. Our data indicated that sclerostin secretion by myeloma cells contribute to the suppression of bone formation in the osteolytic bone disease associated to MM.

Study of the viability and adhesion of osteoblast cells to bone cements mixed with hydroxyapatite at different concentrations to use in vertebral augmentation techniques.

Science.gov (United States)

Pino-Mínguez, J; Jorge-Mora, A; Couceiro-Otero, R; García-Santiago, C

2015-01-01

The purpose of this study is to compare the biocompatibility and the effect in osteoblasts of polymethyl methacrylate alone, and mixed with hydroxyapatite in different concentrations of 5, 10, 15 and 20%, without exceeding 20%, as it can alter mechanical properties of the composite. Experimental study comparing osteoblast response to Polymethyl methacrylate alone and with hydroxyapatite in different concentrations. Composites at 15 and 20% obtained better osteoblast response, with higher osteoblastic activity markers, and lower apoptosis markers. Electron microscopy images show improved adhesion of osteoblasts. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

Electrochemical & osteoblast adhesion study of engineered TiO2 nanotubular surfaces on titanium alloys

International Nuclear Information System (INIS)

Rahman, Zia Ur; Haider, Waseem; Pompa, Luis; Deen, K.M.

2016-01-01

TiO 2 nanotubes were grafted on the surface of cpTi, Ti6Al4V and Ti6Al4V-ELI with the aim to provide a new podium for human pre-osteoblast cell (MC3T3) adhesion and proliferation. The surface morphology and chemistry of these alloys were examined with scanning electron microscopy and energy dispersive x-ray spectroscopy. TiO 2 nanotubes were further characterized by cyclic potentiodynamic polarization tests and electrochemical impedance spectroscopy. The vertically aligned nanotubes were subjected to pre-osteoblast cell proliferation in order to better understand cell–material interaction. The study demonstrated that these cells interact differently with nanotubes of different titanium alloys. The significant acceleration in the growth rate of pre-osteoblast cell adhesion and proliferation is also witnessed. Additionally, the cytotoxicity of the leached metal ions was evaluated by using a tetrazolium-based bio-assay, MTS. Each group of data was operated for p < 0.05, concluded one way ANOVA to investigate the significance difference. - Highlights: • TiO 2 nanotubes were grafted on cpTi, Ti6Al4V and Ti6Al4V-ELI via anodization. • MC3T3 cells interact differently with nanotubes of different titanium alloys. • TiO 2 nanotubes have a positive impact on the osteoblast cell viability.

Telomerase activity promotes osteoblast differentiation by modulating IGF-signaling pathway

DEFF Research Database (Denmark)

Saeed, Hamid; Qiu, Weimin; Li, Chen

2015-01-01

-regulation of several components of insulin-like growth factor (IGF) signaling. Specifically, a significant increase in IGF-induced AKT phosphorylation and alkaline phosphatase (ALP) activity were observed in hMSC-TERT. Enhanced ALP activity was reduced in presence of IGF1 receptor inhibitor: picropodophyllin....... In addition, telomerase deficiency caused significant reduction in IGF signaling proteins in osteoblastic cells cultured from telomerase deficient mice (Terc (-/-)). The low bone mass exhibited by Terc (-/-) mice was associated with significant reduction in serum levels of IGF1 and IGFBP3 as well as reduced...... skeletal mRNA expression of Igf1, Igf2, Igf2r, Igfbp5 and Igfbp6. IGF1-induced osteoblast differentiation was also impaired in Terc (-/-) MSC. In conclusion, our data demonstrate that impaired IGF/AKT signaling contributes to the observed decreased bone mass and bone formation exhibited by telomerase...

Proliferation and osteoblastic differentiation of hMSCs on cellulose-based hydrogels.

Science.gov (United States)

Raucci, Maria Grazia; Alvarez-Perez, Marco Antonio; Demitri, Christian; Sannino, Alessandro; Ambrosio, Luigi

2012-01-01

The aim of this project was to study the proliferation and differentiation of human Mesenchymal Stem Cells (hMSCs) onto a cellulose-based hydrogel for bone tissue engineering. Modified-cellulose hydrogel was prepared via double esterification crosslinking using citric acid. The response of human Mesenchymal Stem Cells (hMSCs) in terms of cell proliferation and differentiation into osteoblastic phenotype was evaluated by using Alamar blue assay and Alkaline phosphatase activity. The results showed that CMCNa and CMCNa_CA have no negative effect on hMSC, adhesion and proliferation. Moreover, the increase of the ALP expression for CMCNa_CA confirms the ability of the hydrogels to support the osteoblastic differentiation. The cellulose-based hydrogels have a potential application as filler in bone tissue regeneration.

Effect of nanometer scale surface roughness of titanium for osteoblast function

Directory of Open Access Journals (Sweden)

Satoshi Migita

2017-02-01

Full Text Available Surface roughness is an important property for metallic materials used in medical implants or other devices. The present study investigated the effects of surface roughness on cellular function, namely cell attachment, proliferation, and differentiation potential. Titanium (Ti discs, with a hundred nanometer- or nanometer-scale surface roughness (rough and smooth Ti surface, respectively were prepared by polishing with silicon carbide paper. MC3T3-E1 mouse osteoblast-like cells were cultured on the discs, and their attachment, spreading area, proliferation, and calcification were analyzed. Cells cultured on rough Ti discs showed reduced attachment, proliferation, and calcification ability suggesting that the surface inhibited osteoblast function. The findings can provide a basis for improving the biocompatibility of medical devices.

Osteoblast-Prostate Cancer Cell Interaction in Prostate Cancer Bone Metastases

National Research Council Canada - National Science Library

Navone, Nora

2001-01-01

.... This suggests that prostate cancer cells interact with cells from the osteoblastic lineage. To understand the molecular bases of prostatic bone metastases, we established two prostate cancer cell lines, MDA PCa 2a and MDA PCa 2b (1...

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells

Energy Technology Data Exchange (ETDEWEB)

Yeh, Lee-Chuan C.; Ford, Jeffery J. [Department of Biochemistry, The University of Texas Health Science Center at San Antonio, TX (United States); Lee, John C. [Department of Biochemistry, The University of Texas Health Science Center at San Antonio, TX (United States); The Sam and Ann Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, TX (United States); Adamo, Martin L., E-mail: adamo@biochem.uthscsa.edu [Department of Biochemistry, The University of Texas Health Science Center at San Antonio, TX (United States); The Sam and Ann Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, TX (United States)

2014-07-18

Highlights: • Palmitate inhibits osteoblast differentiation. • Fatty acid synthase. • PPARγ. • Acetyl Co-A carboxylase inhibitor TOFA. • Fetal rat calvarial cell culture. - Abstract: Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects.

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells

International Nuclear Information System (INIS)

Yeh, Lee-Chuan C.; Ford, Jeffery J.; Lee, John C.; Adamo, Martin L.

2014-01-01

Highlights: • Palmitate inhibits osteoblast differentiation. • Fatty acid synthase. • PPARγ. • Acetyl Co-A carboxylase inhibitor TOFA. • Fetal rat calvarial cell culture. - Abstract: Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects

Ihh controls cartilage development by antagonizing Gli3, but requires additional effectors to regulate osteoblast and vascular development.

Science.gov (United States)

Hilton, Matthew J; Tu, Xiaolin; Cook, Julie; Hu, Hongliang; Long, Fanxin

2005-10-01

Indian hedgehog (Ihh) controls multiple aspects of endochondral skeletal development, including proliferation and maturation of chondrocytes, osteoblast development and cartilage vascularization. Although it is known that Gli transcription factors are key effectors of hedgehog signaling, it has not been established which Gli protein mediates Ihh activity in skeletal development. Here, we show that removal of Gli3 in Ihh-null mouse embryos restored normal proliferation and maturation of chondrocytes, but only partially rescued the defects in osteoblast development and cartilage vascularization. Remarkably, in both Ihh-/- and Ihh-/-; Gli3-/- embryos, vascularization promoted osteoblast development in perichondrial progenitor cells. Our results not only establish Gli3 as a critical effector for Ihh activity in the developing skeleton, but also identify an osteogenic role for a vasculature-derived signal, which integrates with Ihh and Wnt signals to determine the osteoblast versus chondrocyte fate in the mesenchymal progenitors.

Functional response of osteoblasts in functionally gradient titanium alloy mesh arrays processed by 3D additive manufacturing.

Science.gov (United States)

Nune, K C; Kumar, A; Misra, R D K; Li, S J; Hao, Y L; Yang, R

2017-02-01

We elucidate here the osteoblasts functions and cellular activity in 3D printed interconnected porous architecture of functionally gradient Ti-6Al-4V alloy mesh structures in terms of cell proliferation and growth, distribution of cell nuclei, synthesis of proteins (actin, vinculin, and fibronectin), and calcium deposition. Cell culture studies with pre-osteoblasts indicated that the interconnected porous architecture of functionally gradient mesh arrays was conducive to osteoblast functions. However, there were statistically significant differences in the cellular response depending on the pore size in the functionally gradient structure. The interconnected porous architecture contributed to the distribution of cells from the large pore size (G1) to the small pore size (G3), with consequent synthesis of extracellular matrix and calcium precipitation. The gradient mesh structure significantly impacted cell adhesion and influenced the proliferation stage, such that there was high distribution of cells on struts of the gradient mesh structure. Actin and vinculin showed a significant difference in normalized expression level of protein per cell, which was absent in the case of fibronectin. Osteoblasts present on mesh struts formed a confluent sheet, bridging the pores through numerous cytoplasmic extensions. The gradient mesh structure fabricated by electron beam melting was explored to obtain fundamental insights on cellular activity with respect to osteoblast functions. Copyright © 2016 Elsevier B.V. All rights reserved.

Expression of LRP1 by human osteoblasts: a mechanism for the delivery of lipoproteins and vitamin K1 to bone

DEFF Research Database (Denmark)

Niemeier, Andreas; Kassem, Moustapha; Toedter, Klaus

2005-01-01

Accumulating clinical and experimental data show the importance of dietary lipids and lipophilic vitamins, such as vitamin K1, for bone formation. The molecular mechanism of how they enter the osteoblast is unknown. Here we describe the expression of the multifunctional LRP1 by human osteoblasts...... in vitro and in vivo. We provide evidence that LRP1 plays an important role in the uptake of postprandial lipoproteins and vitamin K1 by human osteoblasts....

Differentiation and cytokine synthesis of human alveolar osteoblasts compared to osteoblast-like cells (MG63) in response to titanium surfaces.

Science.gov (United States)

Rausch-fan, Xiaohui; Qu, Zhe; Wieland, Marco; Matejka, Michael; Schedle, Andreas

2008-01-01

The aim of this study was to investigate the influence of different implant surface topographies and chemistries on the expression of differentiation/proliferation markers on MG63 cells and primary human alveolar osteoblasts. Hydrophobic acid-etched (A) and hydrophobic coarse-grit-blasted, acid-etched (SLA) surfaces and hydrophilic acid-etched (modA) and hydrophilic coarse-grit-blasted (modSLA) surfaces were produced. Thereby, modA and modSLA surfaces were rinsed under nitrogen protection and stored in a sealed glass tube containing isotonic NaCl solution at pH 4-6. Tissue culture plates without specimens served as controls. The behavior of MG63 cells and primary human alveolar osteoblasts (AOB) grown on all surfaces was compared through determination of alkaline phosphatase (ALP) activity, cell proliferation ((3)H-thymidin incorporation, MTT colorimetric assay) and expression of osteocalcin (OC), osteoprotegerin (OPG), transforming growth factor-beta1 (TGF-beta(1)) and vascular endothelial growth factor (VEGF), detected with commercial available test kits. Proliferation of MG63 and primary cells was highest on controls, followed by A surfaces, modA and SLA surfaces being almost on the same level and lowest on modSLA surfaces. modSLA surfaces exhibited highest ALP and OC production, followed by SLA, modA and A surfaces. Proliferation and OC production were comparable for MG63 cells and AOB. OPG, TGF-beta(1) and VEGF produced on primary cells showed a slightly different rank order on different surfaces compared to MG63 cells. modSLA still showed the highest production of OPG, TGF-beta(1) and VEGF, but was followed by modA, SLA and A. Statistical significance was checked by ANOVA (pmodA surfaces showed enhanced expression of OPG, TGF-beta(1) and VEGF on MG63 cells compared to primary human alveolar osteoblasts. Overall, the lowest proliferation rates and the highest expressions of differentiation markers and growth factor productions were observed on modSLA.

Osteoblasts derived from osteophytes produce interleukin-6, interleukin-8, and matrix metalloproteinase-13 in osteoarthritis.

Science.gov (United States)

Sakao, Kei; Takahashi, Kenji A; Arai, Yuji; Saito, Masazumi; Honjo, Kuniaki; Hiraoka, Nobuyuki; Asada, Hidetsugu; Shin-Ya, Masaharu; Imanishi, Jiro; Mazda, Osam; Kubo, Toshikazu

2009-01-01

To clarify the significance of the osteophytes that appear during the progression of osteoarthritis (OA), we investigated the expression of inflammatory cytokines and proteases in osteoblasts from osteophytes. We also examined the influence of mechanical stress loading on osteoblasts on the expression of inflammatory cytokines and proteases. Osteoblasts were isolated from osteophytes in 19 patients diagnosed with knee OA and from subchondral bone in 4 patients diagnosed with femoral neck fracture. Messenger RNA expression and protein production of inflammatory cytokines and proteases were analyzed using real-time RT-PCR and ELISA, respectively. To examine the effects of mechanical loading, continuous hydrostatic pressure was applied to the osteoblasts. We determined the mRNA expression and protein production of IL-6, IL-8, and MMP-13, which are involved in the progression of OA, were increased in the osteophytes. Additionally, when OA pathological conditions were simulated by applying a nonphysiological mechanical stress load, the gene expression of IL-6 and IL-8 increased. Our results suggested that nonphysiological mechanical stress may induce the expression of biological factors in the osteophytes and is involved in OA progression. By controlling the expression of these genes in the osteophytes, the progression of cartilage degeneration in OA may be reduced, suggesting a new treatment strategy for OA.

Alternative splicing and expression of the insulin-like growth factor (IGF-1) gene in osteoblasts under mechanical stretch

Institute of Scientific and Technical Information of China (English)

XIAN Chengyu; WANG Yuanliang; ZHANG Bingbing; TANG Liling; PAN Jun; LUO Yanfeng; JIANG Peng; LI Dajun

2006-01-01

Insulin-like growth factor 1 (IGF-1) promotes osteoblasts differentiation and bone formation,and its expression is induced by mechanical stretch,thus IGF-1 has been considered an effector molecule that links mechanical stimulation and local tissue responses. In this study, a mechanical stretching device was designed to apply physiological level static or cyclic stretching stimulation to osteoblasts.Different isoforms of IGF-1 mRNA were amplified by RT-PCR from the cells using respective primers and these amplified products were sequenced. An isoform of IGF-1 splicing product was found to be selectively produced by osteoblasts under stretching stimulation. This IGF-1 isoform had identical sequence with the mechano growth factor (MGF) which was originally identified in muscle cells. Regulations of the expression of the liver-type IGF (L.IGF-1) and MGF in osteoblasts under stretch stimulation were further studied using semi-quantitative RT-PCR.Stretch stimulation was found to promot the expression of IGF-1 (L.IGF-1 and MGF), and for both isoforms expression was more effectively stimulated by cyclic stretch than static stretch. MGF was detected only in osteoblasts subjected to mechanical stretch,suggesting MGF was a stretch sensitive growth factor.Expression of MGF peaked earlier than that of L.IGF-1, which was similar to their regulation in muscie and suggested similar roles of MGF and L.IGF-1in bone as in muscle cells. The functions of MGF and L.IGF-1 in osteoblasts shall be established by further experimental studies.

Effects of fluoridation of porcine hydroxyapatite on osteoblastic activity of human MG63 cells

International Nuclear Information System (INIS)

Li, Zhipeng; Huang, Baoxin; Mai, Sui; Wu, Xiayi; Zhang, Hanqing; Qiao, Wei; Luo, Xin; Chen, Zhuofan

2015-01-01

Biological hydroxyapatite, derived from animal bones, is the most widely used bone substitute in orthopedic and dental treatments. Fluorine is the trace element involved in bone remodeling and has been confirmed to promote osteogenesis when administered at the appropriate dose. To take advantage of this knowledge, fluorinated porcine hydroxyapatite (FPHA) incorporating increasing levels of fluoride was derived from cancellous porcine bone through straightforward chemical and thermal treatments. Physiochemical characteristics, including crystalline phases, functional groups and dissolution behavior, were investigated on this novel FPHA. Human osteoblast-like MG63 cells were cultured on the FPHA to examine cell attachment, cytoskeleton, proliferation and osteoblastic differentiation for in vitro cellular evaluation. Results suggest that fluoride ions released from the FPHA play a significant role in stimulating osteoblastic activity in vitro, and appropriate level of fluoridation (1.5 to 3.1 atomic percents of fluorine) for the FPHA could be selected with high potential for use as a bone substitute. (paper)

Expression of osteoblast and osteoclast regulatory genes in the bone marrow microenvironment in multiple myeloma

DEFF Research Database (Denmark)

Kristensen, Ida B; Christensen, Jacob Haaber; Lyng, Maria Bibi

2014-01-01

Multiple myeloma (MM) lytic bone disease (LBD) is caused by osteoclast activation and osteoblast inhibition. RANK/RANKL/OPG play central roles in osteoclast activation and Wnt inhibitor DKK1 in osteoblast inhibition. The role of other Wnt inhibitors is less clear. We evaluated gene expression...... of osteoclast regulators (RANK, RANKL, OPG, TRAIL, MIP1A), Wnt inhibitors (DKK1, SFRP2, SFRP3, sclerostin, WIF1) and osteoblast transcription factors (RUNX2, osterix) by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in the bone marrow (BM) microenvironment using snap-frozen BM biopsies...... radiographs and the bone resorption marker CTX-1. Protein levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. Among Wnt inhibitors, only SFRP3 and DKK1 were significantly overexpressed in advanced LBD, correlating with protein levels. SFRP3 correlated with CTX-1. Our...

ent-Kaurane diterpenoids from Croton tonkinensis stimulate osteoblast differentiation

DEFF Research Database (Denmark)

Dao, Trong-Tuan; Lee, Kwang-Youl; Jeong, Hyung-Min

2011-01-01

Four new ent-kaurane diterpenoids (1-4) were isolated from the leaves of Croton tonkinensis by bioactivity-guided fractionation using an in vitro osteoblast differentiation assay. Their structures were identified as ent-11β-acetoxykaur-16-en-18-ol (1), ent-11α-hydroxy-18-acetoxykaur-16-ene (2), e...

The effects of low dose X-irradiation on osteoblastic MC3T3-E1 cells in vitro

Directory of Open Access Journals (Sweden)

Xu Wei

2012-06-01

Full Text Available Abstract Background It has been indicated that moderate or high dose of X-irradiation could delay fracture union and cause osteoradionecrosis, in part, mediated by its effect on proliferation and differentiation of osteoblasts. However, whether low dose irradiation (LDI has similar roles on osteoblasts is still unknown. In this study, we investigated whether and to what extent LDI could affect the proliferation, differentiation and mineralization of osteoblasts in vitro. Methods The MC3T3-E1 cells were exposed to single dose of X-irradiation with 0, 0.1, 0.5, 1.0 Gy respectively. Cell proliferation, apoptosis, alkaline phosphatase (ALP activity, and mineralization was evaluated by methylthiazoletetrazolium (MTT and bromodeoxyuridine (BrdU assay, flow cytometry, ALP viability kit and von Kossa staining, respectively. Osteocalcin (OCN and core-binding factor α1 (Cbfα1 expressions were measured by real time-PCR and western blot, respectively. Results The proliferation of the cells exposed to 2.0 Gy was significantly lower than those exposed to ≤1.0 Gy (p  Conclusions LDI have different effects on proliferation and differentiation of osteoblasts from those of high dose of X-irradiation, which might suggest that LDI could lead to promotion of frature healing through enhancing the differentiation and mineralization of osteoblasts.

Specific proliferation rates of human osteoblasts on calcium phosphate surfaces with variable concentrations of α-TCP

International Nuclear Information System (INIS)

Santos, Euler A. dos; Farina, Marcos; Soares, Gloria A.

2007-01-01

Ideally, ceramics used in the repair of bone defects need to be resorbed and replaced by newly formed bone in vivo. Tricalcium phosphate (TCP) has been widely used in association with hydroxyapatite (HA) due to its higher resorption kinetics when compared with HA alone. The aim of our study was to quantitatively investigate the effect of α-tricalcium phosphate (α-TCP) on human osteoblasts' adhesion and proliferation. Ceramic samples with variable concentrations of α-TCP and HA were produced by the calcination of calcium-deficient and stoichiometric HA. Human osteoblasts were cultured on the materials in three distinct experiments with different concentrations of cells. Numerical evaluation of cellular growth along time in culture was performed for each condition. The quantity of cells seeded onto the ceramics seems to influence the osteoblast behavior once proliferation was lower when more cells were seeded onto the samples. However, a smaller content of α-TCP in relation to that of HA did not significantly modify the specific proliferation rates of the osteoblasts. Only after a long time in culture, the increasing of the α-TCP content seems to change the cells' behavior

Maturation of osteoblast-like SaoS2 induced by carbon nanotubes

International Nuclear Information System (INIS)

Li Xiaoming; Uo, Motohiro; Akasaka, Tsukasa; Abe, Shigeaki; Watari, Fumio; Gao Hong; Sato, Yoshinori; Feng Qingling; Cui Fuzhai

2009-01-01

Osteogenic maturation of the osteoblast is crucial for bone formation. In this study, multi-walled carbon nanotubes (MWCNTs) and graphite (GP) were pressed as compacts. The greater ability of carbon nanotubes to adsorb proteins, compared with graphite, was shown. Human osteoblast-like SaoS2 cells were cultured and the cell response to the two kinds of compacts was compared in vitro. Meanwhile, we used cell culture on the culture plate as a control. Assays for osteonectin, osteopontin and osteocalcin gene expression, total protein (TP) amount, alkaline phosphatase activity (ALP) and DNA of cells cultured on the samples were done. During the conventional culture, significantly higher osteonectin, osteopontin and osteocalcin gene expression level, ALP/DNA and TP/DNA on carbon nanotubes were found. To confirm the hypothesis that the larger amount of specific proteins adsorbed on the carbon nanotubes was crucial for this, the compacts were pre-soaked in culture medium having additional recombinant human bone morphogenetic protein-2 (rhBMP-2) before cell culture. Compared with GP, osteonectin, osteopontin and osteocalcin gene expression level, ALP/DNA and TP/DNA of the cells tested increased more on the MWCNTs after the compacts were pre-soaked in the culture medium with rhBMP-2. The results indicated that the carbon nanotubes might induce osteogenic maturation of the osteoblast by adsorbing more specific proteins.

Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function

DEFF Research Database (Denmark)

Furlan, Federico; Galbiati, Clara; Jørgensen, Niklas R

2007-01-01

of macrophage-colony stimulating factor (M-CSF) and RANKL. Phalloidin staining in osteoclasts served to study actin ring and podosome formation. RESULTS: pQCT revealed increased bone mass in uPAR-null mice. Mechanical tests showed reduced load-sustaining capability in uPAR KO tibias. uPAR KO osteoblasts showed...... a proliferative advantage with no difference in apoptosis, higher matrix mineralization, and earlier appearance of alkaline phosphatase (ALP). Surface RANKL expression at different stages of differentiation was not altered. AP-1 components, such as JunB and Fra-1, were upregulated in uPAR KO osteoblasts, along...

Recql4 haploinsufficiency in mice leads to defects in osteoblast progenitors: Implications for low bone mass phenotype

International Nuclear Information System (INIS)

Yang Jieping; Murthy, Sreemala; Winata, Therry; Werner, Sean; Abe, Masumi; Prahalad, Agasanur K.; Hock, Janet M.

2006-01-01

The cellular and molecular mechanisms that underlie skeletal abnormalities in defective Recql4-related syndromes are poorly understood. Our objective in this study was to explore the function of Recql4 in osteoblast biology both in vitro and in vivo. Immunohistochemistry on adult mouse bone showed Recql4 protein localization in active osteoblasts around growth plate, but not in fully differentiated osteocytes. Consistent with this finding, Recql4 gene expression was high in proliferating mouse osteoblastic MC3T3.E1 cells and decreased as cells progressively lost their proliferation activity during differentiation. Recql4 overexpression in osteoblastic cells exhibited higher proliferation activity, while its depletion impeded cell growth. In addition, bone marrow stromal cells from male Recql4+/- mice had fewer progenitor cells, including osteoprogenitors, indicated by reduced total fibroblast colony forming units (CFU-f) and alkaline phosphatase-positive CFU-f colonies concomitant with reduced bone mass. These findings provide evidence that Recql4 functions as a regulatory protein during osteoprogenitor proliferation, a critical cellular event during skeleton development

Plasma membrane factor XIIIA transglutaminase activity regulates osteoblast matrix secretion and deposition by affecting microtubule dynamics.

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Hadil F Al-Jallad

2011-01-01

Full Text Available Transglutaminase activity, arising potentially from transglutaminase 2 (TG2 and Factor XIIIA (FXIIIA, has been linked to osteoblast differentiation where it is required for type I collagen and fibronectin matrix deposition. In this study we have used an irreversible TG-inhibitor to 'block -and-track' enzyme(s targeted during osteoblast differentiation. We show that the irreversible TG-inhibitor is highly potent in inhibiting osteoblast differentiation and mineralization and reduces secretion of both fibronectin and type I collagen and their release from the cell surface. Tracking of the dansyl probe by Western blotting and immunofluorescence microscopy demonstrated that the inhibitor targets plasma membrane-associated FXIIIA. TG2 appears not to contribute to crosslinking activity on the osteoblast surface. Inhibition of FXIIIA with NC9 resulted in defective secretory vesicle delivery to the plasma membrane which was attributable to a disorganized microtubule network and decreased microtubule association with the plasma membrane. NC9 inhibition of FXIIIA resulted in destabilization of microtubules as assessed by cellular Glu-tubulin levels. Furthermore, NC9 blocked modification of Glu-tubulin into 150 kDa high-molecular weight Glu-tubulin form which was specifically localized to the plasma membrane. FXIIIA enzyme and its crosslinking activity were colocalized with plasma membrane-associated tubulin, and thus, it appears that FXIIIA crosslinking activity is directed towards stabilizing the interaction of microtubules with the plasma membrane. Our work provides the first mechanistic cues as to how transglutaminase activity could affect protein secretion and matrix deposition in osteoblasts and suggests a novel function for plasma membrane FXIIIA in microtubule dynamics.

Biphasic Response to Luteolin in MG-63 Osteoblast-Like Cells under High Glucose‑Induced Oxidative Stress

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Naser Abbasi

2016-03-01

Full Text Available Background: Clinical evidence indicates the diabetes-induced impairment of osteogenesis caused by a decrease in osteoblast activity. Flavonoids can increase the differentiation and mineralization of osteoblasts in a high-glucose state. However, some flavonoids such as luteolin may have the potential to induce cytotoxicity in osteoblast-like cells. This study was performed to investigate whether a cytoprotective concentration range of luteolin could be separated from a cytotoxic concentration range in human MG-63 osteoblast-like cells in high-glucose condition. Methods: Cells were cultured in a normal- or high-glucose medium. Cell viability was determined with the MTT assay. The formation of intracellular reactive oxygen species (ROS was measured using probe 2’,7’ -dichlorofluorescein diacetate, and osteogenic differentiation was evaluated with an alkaline phosphatase bioassay. Results: ROS generation, reduction in alkaline phosphatase activity, and cell death induced by high glucose were inhibited by lower concentrations of luteolin (EC50, 1.29±0.23 µM. Oxidative stress mediated by high glucose was also overcome by N-acetyl-L-cysteine. At high concentrations, luteolin caused osteoblast cell death in normal- and high-glucose states (IC50, 34±2.33 and 27±2.42 µM, respectively, as represented by increased ROS and decreased alkaline phosphatase activity. Conclusion: Our results indicated that the cytoprotective action of luteolin in glucotoxic condition was manifested in much lower concentrations, by a factor of approximately 26 and 20, than was its cytotoxic activity, which occurred under normal or glucotoxic condition, respectively.

The shunt from the cyclooxygenase to lipoxygenase pathway in human osteoarthritic subchondral osteoblasts is linked with a variable expression of the 5-lipoxygenase-activating protein.

Science.gov (United States)

Maxis, Kelitha; Delalandre, Aline; Martel-Pelletier, Johanne; Pelletier, Jean-Pierre; Duval, Nicolas; Lajeunesse, Daniel

2006-01-01

Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic bone changes with osteophyte formation and abnormal bone remodeling. Two groups of OA patients were identified via the production of variable and opposite levels of prostaglandin E2 (PGE2) or leukotriene B4 (LTB4) by subchondral osteoblasts, PGE2 levels discriminating between low and high subgroups. We studied whether the expression of 5-lipoxygenase (5-LO) or 5-LO-activating protein (FLAP) is responsible for the shunt from prostaglandins to leukotrienes. FLAP mRNA levels varied in low and high OA groups compared with normal, whereas mRNA levels of 5-LO were similar in all osteoblasts. Selective inhibition of cyclooxygenase-2 (COX-2) with NS-398-stimulated FLAP expression in the high OA osteoblasts subgroup, whereas it was without effect in the low OA osteoblasts subgroup. The addition of PGE2 to the low OA osteoblasts subgroup decreased FLAP expression but failed to affect it in the high OA osteoblasts subgroup. LTB4 levels in OA osteoblasts were stimulated about twofold by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plus transforming growth factor-beta (TGF-beta), a situation corresponding to their effect on FLAP mRNA levels. Treatments with 1,25(OH)2D3 and TGF-beta also modulated PGE2 production. TGF-beta stimulated PGE2 production in both OA osteoblast groups, whereas 1,25(OH)2D3 alone had a limited effect but decreased the effect of TGF-beta in the low OA osteoblasts subgroup. This modulation of PGE2 production was mirrored by the synthesis of COX-2. IL-18 levels were only slightly increased in a subgroup of OA osteoblasts compared with normal; however, no relationship was observed overall between IL-18 and PGE2 levels in normal and OA osteoblasts. These results suggest that the shunt from the production of PGE2 to LTB4 is through regulation of the expression of FLAP, not 5-LO, in OA osteoblasts. The expression of FLAP in OA osteoblasts is also modulated differently by 1,25(OH

Transduction of Oct6 or Oct9 gene concomitant with Myc family gene induced osteoblast-like phenotypic conversion in normal human fibroblasts.

Science.gov (United States)

Mizoshiri, N; Kishida, T; Yamamoto, K; Shirai, T; Terauchi, R; Tsuchida, S; Mori, Y; Ejima, A; Sato, Y; Arai, Y; Fujiwara, H; Yamamoto, T; Kanamura, N; Mazda, O; Kubo, T

2015-11-27

Osteoblasts play essential roles in bone formation and regeneration, while they have low proliferation potential. Recently we established a procedure to directly convert human fibroblasts into osteoblasts (dOBs). Transduction of Runx2 (R), Osterix (X), Oct3/4 (O) and L-myc (L) genes followed by culturing under osteogenic conditions induced normal human fibroblasts to express osteoblast-specific genes and produce calcified bone matrix both in vitro and in vivo Intriguingly, a combination of only two factors, Oct3/4 and L-myc, significantly induced osteoblast-like phenotype in fibroblasts, but the mechanisms underlying the direct conversion remains to be unveiled. We examined which Oct family genes and Myc family genes are capable of inducing osteoblast-like phenotypic conversion. As result Oct3/4, Oct6 and Oct9, among other Oct family members, had the capability, while N-myc was the most effective Myc family gene. The Oct9 plus N-myc was the best combination to induce direct conversion of human fibroblasts into osteoblast-like cells. The present findings may greatly contribute to the elucidation of the roles of the Oct and Myc proteins in osteoblast direct reprogramming. The results may also lead to establishment of novel regenerative therapy for various bone resorption diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

Monitoring Bone Tissue Engineered (BTE) Constructs Based on the Shifting Metabolism of Differentiating Stem Cells.

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Simmons, Aaron D; Sikavitsas, Vassilios I

2018-01-01

Ever-increasing demand for bone grafts necessitates the realization of clinical implementation of bone tissue engineered constructs. The predominant hurdle to implementation remains to be securing FDA approval, based on the lack of viable methods for the rigorous monitoring of said constructs. The study presented herein details a method for such monitoring based on the shifting metabolism of mesenchymal stem cells (MSCs) as they differentiate into osteoblasts. To that end, rat MSCs seeded on 85% porous spunbonded poly(L-lactic acid) scaffolds were cultured in flow perfusion bioreactors with baseline or osteoinductive media, and levels of key physio-metabolic markers (oxygen, glucose, osteoprotegerin, and osteocalcin) were monitored throughout culture. Comparison of these non-destructively obtained values and current standard destructive analyses demonstrated key trends useful for the concurrent real-time monitoring of construct cellularity and maturation. Principle among these is the elucidation of the ratio of the rates of oxygen uptake to glucose consumption as a powerful quality marker. This ratio, supported on a physiological basis, has been shown herein to be reliable in the determination of both construct maturation (defined as osteoblastic differentiation and accompanying mineralization) and construct cellularity. Supplementary monitoring of OPG and OCN are shown to provide further validation of such metrics.

Osteoblast Differentiation and Bone Formation Gene Expression in Strontium-inducing Bone Marrow Mesenchymal Stem Cell

OpenAIRE

SILA-ASNA, MONNIPHA; BUNYARATVEJ, AHNOND; Maeda, Sakan; Kitaguchi, Hiromichi; BUNYARATAVEJ, NARONG

2007-01-01

Osteoblastic differentiation from human mesenchymal stem cell (hMSCs) is animportant step of bone formation. We studied the in vitro induction of hMSCs byusing strontium ranelate, a natural trace amount in water, food and human skeleton.The mRNA synthesis of various osteoblast specific genes was assessed by means ofreverse transcription polymerase chain reaction (RT-PCR). In the hMSCs culture,strontium ranelate could enhance the induction of hMSCs to differentiate intoosteoblasts. Cbfa1 gene ...

Three-dimensional spheroid culture promotes odonto/osteoblastic differentiation of dental pulp cells.

Science.gov (United States)

Yamamoto, Mioko; Kawashima, Nobuyuki; Takashino, Nami; Koizumi, Yu; Takimoto, Koyo; Suzuki, Noriyuki; Saito, Masahiro; Suda, Hideaki

2014-03-01

Three-dimensional (3D) spheroid culture is a method for creating 3D aggregations of cells and their extracellular matrix without a scaffold mimicking the actual tissues. The aim of this study was to evaluate the effects of 3D spheroid culture on the phenotype of immortalized mouse dental papilla cells (MDPs) that have the ability to differentiate into odontoblasts. We cultured MDPs for 1, 3, 7, and 14 days in 96-well low-attachment culture plates for 3D spheroid culture or flat-bottomed plates for two-dimensional (2D) monolayer culture. Cell proliferation and apoptosis were detected by immunohistochemical staining of Ki67 and cleaved caspase-3, respectively. Hypoxia was measured by the hypoxia probe LOX-1. Odonto/osteoblastic differentiation marker gene expression was evaluated by quantitative PCR. We also determined mineralized nodule formation, alkaline phosphatase (ALP) activity, and dentine matrix protein-1 (DMP1) expression. Vinculin and integrin signalling-related proteins were detected immunohistochemically. Odonto/osteoblastic marker gene expression and mineralized nodule formation were significantly up-regulated in 3D spheroid-cultured MDPs compared with those in 2D monolayer-cultured MDPs (podonto/osteoblastic differentiation of MDPs, which may be mediated by integrin signalling. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mechanical stress activates Smad pathway through PKCδ to enhance interleukin-11 gene transcription in osteoblasts.

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Shinsuke Kido

Full Text Available BACKGROUND: Mechanical stress rapidly induces ΔFosB expression in osteoblasts, which binds to interleukin (IL-11 gene promoter to enhance IL-11 expression, and IL-11 enhances osteoblast differentiation. Because bone morphogenetic proteins (BMPs also stimulate IL-11 expression in osteoblasts, there is a possibility that BMP-Smad signaling is involved in the enhancement of osteoblast differentiation by mechanical stress. The present study was undertaken to clarify whether mechanical stress affects BMP-Smad signaling, and if so, to elucidate the role of Smad signaling in mechanical stress-induced enhancement of IL-11 gene transcription. METHODOLOGY/PRINCIPAL FINDINGS: Mechanical loading by fluid shear stress (FSS induced phosphorylation of BMP-specific receptor-regulated Smads (BR-Smads, Smad1/5, in murine primary osteoblasts (mPOBs. FSS rapidly phosphorylated Y311 of protein kinase C (PKCδ, and phosphorylated PKCδ interacted with BR-Smads to phosphorylate BR-Smads. Transfection of PKCδ siRNA or Y311F mutant PKCδ abrogated BR-Smads phosphorylation and suppressed IL-11 gene transcription enhanced by FSS. Activated BR-Smads bound to the Smad-binding element (SBE of IL-11 gene promoter and formed complex with ΔFosB/JunD heterodimer via binding to the C-terminal region of JunD. Site-directed mutagenesis in the SBE and the AP-1 site revealed that both SBE and AP-1 sites were required for full activation of IL-11 gene promoter by FSS. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that PKCδ-BR-Smads pathway plays an important role in the intracellular signaling in response to mechanical stress, and that a cross-talk between PKCδ-BR-Smads and ΔFosB/JunD pathways synergistically stimulates IL-11 gene transcription in response to mechanical stress.

Pharmacological activation of aldehyde dehydrogenase 2 promotes osteoblast differentiation via bone morphogenetic protein-2 and induces bone anabolic effect

Energy Technology Data Exchange (ETDEWEB)

Mittal, Monika; Pal, Subhashis; China, Shyamsundar Pal; Porwal, Konica [Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226031 (India); Dev, Kapil [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Shrivastava, Richa [Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Raju, Kanumuri Siva Rama; Rashid, Mamunur [Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Trivedi, Arun Kumar; Sanyal, Sabyasachi [Biochemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Wahajuddin, Muhammad [Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Bhaduria, Smrati [Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Maurya, Rakesh [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Chattopadhyay, Naibedya, E-mail: n_chattopadhyay@cdri.res.in [Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226031 (India)

2017-02-01

Aldehyde dehydrogenases (ALDHs) are a family of enzymes involved in detoxifying aldehydes. Previously, we reported that an ALDH inhibitor, disulfiram caused bone loss in rats and among ALDHs, osteoblast expressed only ALDH2. Loss-of-function mutation in ALDH2 gene is reported to cause bone loss in humans which suggested its importance in skeletal homeostasis. We thus studied whether activating ALDH2 by N-(1, 3-benzodioxol-5-ylmethyl)-2, 6-dichlorobenzamide (alda-1) had osteogenic effect. We found that alda-1 increased and acetaldehyde decreased the differentiation of rat primary osteoblasts and expressions of ALDH2 and bone morphogenetic protein-2 (BMP-2). Silencing ALDH2 in osteoblasts abolished the alda-1 effects. Further, alda-1 attenuated the acetaldehyde-induced lipid-peroxidation and oxidative stress. BMP-2 is essential for bone regeneration and alda-1 increased its expression in osteoblasts. We then showed that alda-1 (40 mg/kg dose) augmented bone regeneration at the fracture site with concomitant increase in BMP-2 protein compared with control. The osteogenic dose (40 mg/kg) of alda-1 attained a bone marrow concentration that was stimulatory for osteoblast differentiation, suggesting that the tissue concentration of alda-1 matched its pharmacologic effect. In addition, alda-1 promoted modeling-directed bone growth and peak bone mass achievement, and increased bone mass in adult rats which reiterated its osteogenic effect. In osteopenic ovariectomized (OVX) rats, alda-1 reversed trabecular osteopenia with attendant increase in serum osteogenic marker (procollagen type I N-terminal peptide) and decrease in oxidative stress. Alda-1 has no effect on liver and kidney function. We conclude that activating ALDH2 by alda-1 had an osteoanabolic effect involving increased osteoblastic BMP-2 production and decreased OVX-induced oxidative stress. - Highlights: • Alda-1 induced osteoblast differentiation that involved upregulation of ALDH2 and BMP-2 • Alda-1

Osteoblastic cells trigger gate currents on nanocrystalline diamond transistor

Czech Academy of Sciences Publication Activity Database

Ižák, Tibor; Krátká, Marie; Kromka, Alexander; Rezek, Bohuslav

2015-01-01

Roč. 129, May (2015), 95-99 ISSN 0927-7765 R&D Projects: GA ČR GAP108/12/0996 Grant - others:AVČR(CZ) M100101209 Institutional support: RVO:68378271 Keywords : field-effect transistors * nanocrystalline diamond * osteoblastic cells * leakage currents Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.902, year: 2015

Biochemical markers of bone metabolism reflect osteoclastic and osteoblastic activity in multiple myeloma

DEFF Research Database (Denmark)

Abildgaard, N; Glerup, H; Rungby, Jørgen

2000-01-01

In order to evaluate the use of recently developed assays of bone metabolism in multiple myeloma we performed a histomorphometric study of bone biopsies in 16 myeloma patients. Furthermore, we measured the levels of interleukin-6 (IL-6), soluble IL-6 receptor (IL-6sR), IL-1beta, tumour necrosis f...

Human mesenchymal stem cell osteoblast differentiation, ECM deposition, and biomineralization on PAH/PAA polyelectrolyte multilayers.

Science.gov (United States)

Pattabhi, Sudhakara Rao; Lehaf, Ali M; Schlenoff, Joseph B; Keller, Thomas C S

2015-05-01

Polyelectrolyte multilayer (PEMU) coatings built layer by layer with alternating pairs of polyelectrolytes can be tuned to improve cell interactions with surfaces and may be useful as biocompatible coatings to improve fixation between implants and tissues. Here, we show that human mesenchymal stromal cells (hMSCs) induced with bone differentiation medium (BDM) to become osteoblasts biomineralize crosslinked PEMUs built with the polycation poly(allylamine hydrochloride) (PAH) and the polyanion poly(acrylic acid) (PAA). Degrees of hMSC osteoblast differentiation and surface biomineralization on the smooth PAH-terminated PEMUs (PAH-PEMUs) and microstructured PAA-terminated PEMUs (PAA-PEMUs) reflect differences in cell-deposited extracellular matrix (ECM). BDM-induced hMSCs expressed higher levels of the early osteoblast differentiation marker alkaline phosphatase and collagen 1 (COL1) sooner on PAA-PEMUs than on PAH-PEMUs. Cells on both types of PEMUs proceeded to express the later stage osteoblast differentiation marker bone sialoprotein (BSP), but the BDM-induced cells organized a more amorphous Collagen I and denser BSP localization on PAA-PEMUs than on PAH-PEMUs. These ECM properties correlated with greater biomineralization on the PAA-PEMUs than on PAH-PEMUs. Together, these results confirm the suitability of PAH/PAA PEMUs as a substrate for hMSC osteogenesis and highlight the importance of substrate effects on ECM organization and BSP presentation on biomineralization. © 2014 Wiley Periodicals, Inc.

The effect of caffeine on osteoblast proliferation after tooth extraction in Wistar rats

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Budi Yuwono

2006-03-01

Full Text Available Caffeine is the most well-known substance which consumed by most people daily. Behind its popularity as favorable drinks and food, this substance also known can inhibit the post extraction wound healing by decreasing the proliferation of osteoblast cells through the increase of intracellular cyclic Adenosine Mono Phosphate (cAMP. The objective of this study was done to observe the effect of caffeine intake toward the number of osteoblast cells during the wound healing of post dental extraction in Wistar’s rats. This study was an experimental laboratory research and the post test-only control group design was used for the statistical evaluation. The samples used were 24 healthy 3 months old male Wistar’s rats, with approximately 200 grams of body weight and devided into 4 groups. Three groups were taken and represented as a treated group (P and the rest of one group was used as a control group (KO. Caffeine diet with a dosage of 3.78 mg/100 ml grams of body weight/cc was given for 7 days in group P1, P2 for 14 days, and 21 days in group P3 and the diet was given orally using an oral sonde. Teeth extractions of the right first molar in the lower jaw were done in all groups according to the interval time had been scheduled. Seven days of post-extraction time was waiting in all groups before the sample being decapitated for further histological examination in the post extracted sites. A Hematoxillin and Eosin staining was used and the number of osteoblast cells were counted under light microscopy with 400 times magnification. One-way ANOVA and Least Significant Difference (LSD test were used for the statistical evaluation. The result of the study shown a significant decrease of the number of osteoblast cells in caffeine consumed group of 7, 14, and 21 days observed (p < 0.05. This study conclude that the duration time of caffeine consumed had been interfered significantly with the osteoblast cell proliferation during the wound healing after

Use of green fluorescent fusion protein to track activation of the transcription factor osterix during early osteoblast differentiation

International Nuclear Information System (INIS)

Tai Guangping; Christodoulou, Ioannis; Bishop, Anne E.; Polak, Julia M.

2005-01-01

Osterix (Osx) is a transcription factor required for the differentiation of preosteoblasts into fully functioning osteoblasts. However, the pattern of Osx activation during preosteoblast differentiation and maturation has not been clearly defined. Our aim was to study Osx activation during these processes in osteoblasts differentiating from murine and human embryonic stem cells (ESC). To do this, we constructed an Osx-GFP fusion protein reporter system to track Osx translocation within the cells. The distribution of Osx-GFP at representative stages of differentiation was also investigated by screening primary osteoblasts, mesenchymal stem cells, synoviocytes, and pre-adipocytes. Our experiments revealed that Osx-GFP protein was detectable in the cytoplasm of cultured, differentiated ESC 4 days after plating of enzymatically dispersed embryoid bodies. Osterix-GFP protein became translocated into the nucleus on day 7 following transfer of differentiated ESC to osteogenic medium. After 14 days of differentiation, cells showing nuclear translocation of Osx-GFP formed rudimentary bone nodules that continued to increase in number over the following weeks (through day 21). We also found that Osx translocated into the nuclei of mesenchymal stem cells (C3H10T1/2) and pre-osteoblasts (MC3T3-E1) and showed partial activation in pre-adipocytes (MC3T3-L1). These data suggest that Osx activation occurs at a very early point in the differentiation of the mesenchymal-osteoblastic lineage

The effect of globin scaffold on osteoblast adhesion and phenotype expression in vitro.

Science.gov (United States)

Hamdan, Ahmad A; Loty, Sabine; Isaac, Juliane; Tayot, Jean-Louis; Bouchard, Philippe; Khraisat, Ameen; Bedral, Ariane; Sautier, Jean-Michel

2012-01-01

Different synthetic and natural biomaterials have been used in bone tissue regeneration. However, several limitations are associated with the use of synthetic as well as allogenous or xenogenous natural materials. This study evaluated, in an in vitro model, the behavior of rat osteoblastic cells cultured on a human globin scaffold. Rat osteoblastic cells were isolated from the calvaria of 21-day-old fetal Sprague-Dawley rats. They were then grown in the presence of globin. Real-time polymerase chain reaction (RT-PCR) was performed to study the expression of cyclin D1, integrin Β1, Msx2, Dlx5, Runx2, and osteocalcin on days 1, 5, and 9. Moreover, alkaline phosphatase activity was measured on days 1, 3, 5, and 7. Alizarin red staining was performed on day 9 to observe calcium deposition. Cells were able to adhere, proliferate, and differentiate on globin scaffolds. Moreover, RT-PCR showed that globin may stimulate some key genes of osteoblastic differentiation (Runx2, osteocalcin, Dlx5). Globin had an inhibitory effect on alkaline phosphatase activity. Calcium deposits were seen after 9 days of culture. These results indicate that purified human globin might be a suitable scaffold for bone tissue regeneration.

Beneficial Effects of Concentrated Growth Factors and Resveratrol on Human Osteoblasts In Vitro Treated with Bisphosphonates

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Elisa Borsani

2018-01-01

Full Text Available Bisphosphonates are primary pharmacological agents against osteoclast-mediated bone loss and widely used in the clinical practice for prevention and treatment of a variety of skeletal conditions, such as low bone density and osteogenesis imperfecta, and pathologies, such as osteoporosis, malignancies metastatic to bone, Paget disease of bone, multiple myeloma, and hypercalcemia of malignancy. However, long-term bisphosphonate treatment is associated with pathologic conditions including osteonecrosis of the jaw, named BRONJ, which impaired bone regeneration process. Clinical management of BRONJ is controversy and one recent approach is the use of platelet concentrates, such as Concentrated Growth Factors, alone or together with biomaterials or antioxidants molecules, such as resveratrol. The aim of the present study was to investigate the in vitro effects of Concentrated Growth Factors and/or resveratrol on the proliferation and differentiation of human osteoblasts, treated or not with bisphosphonates. Human osteoblasts were stimulated for 3 days in complete medium and for 21 days in mineralization medium. At the end of the experimental period, the in vitro effect on osteoblast proliferation and differentiation was evaluated using different techniques such as MTT, ELISA for the quantification/detection of osteoprotegerin and bone morphogenetic protein-2, immunohistochemistry for sirtuin 1 and collagen type I, and the Alizarin Red S staining for the rate of mineralization. Results obtained showed that Concentrated Growth Factors and/or resveratrol significantly increased osteoblast proliferation and differentiation and that the cotreatment with Concentrated Growth Factors and resveratrol had a protective role on osteoblasts treated with bisphosphonates. In conclusion, these data suggest that this approach could be promised in the clinical management of BRONJ.

Nano-hydroxyapatite modulates osteoblast lineage commitment by stimulation of DNA methylation and regulation of gene expression

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Ha, Shin-Woo; Jang, Hae Lin; Nam, Ki Tae; Beck, George R.

2015-01-01

Hydroxyapatite (HA) is the primary structural component of the skeleton and dentition. Under biological conditions, HA does not occur spontaneously and therefore must be actively synthesized by mineralizing cells such as osteoblasts. The mechanism(s) by which HA is actively synthesized by cells and deposited to create a mineralized matrix are not fully understood and the consequences of mineralization on cell function are even less well understood. HA can be chemically synthesized (HAp) and is therefore currently being investigated as a promising therapeutic biomaterial for use as a functional scaffold and implant coating for skeletal repair and dental applications. Here we investigated the biological effects of nano-HAp (10×100 nm) on the lineage commitment and differentiation of bone forming osteoblasts. Exposure of early stage differentiating osteoblasts resulted in dramatic and sustained changes in gene expression, both increased and decreased, whereas later stage osteoblasts were much less responsive. Analysis of the promoter region one of the most responsive genes, alkaline phosphatase, identified the stimulation of DNA methylation following cell exposure to nano-HAp. Collectively, the results reveal the novel epigenetic regulation of cell function by nano-HAp which has significant implication on lineage determination as well as identifying a novel potential therapeutic use of nanomaterials. PMID:26141836

Expression Profiles of TGF-β and TLR Pathways in Porphyromonas gingivalis and Prevotella intermedia Challenged Osteoblasts.

Science.gov (United States)

Aydin, Kubra; Ekinci, Fatma Yesim; Korachi, May

2015-04-01

The presence of certain oral pathogens at implant sites can hinder the osseointegration process. However, it is unclear how and by what microorganisms it happens. This study investigated whether the presence of oral pathogens of Porphyromonas gingivalis and Prevotella intermedia individually, play a role in the failure of bone formation by determining the expression profiles of Transforming Growth Factor Beta (TGF-β/Bone Morphogenic Protein (BMP) and Toll-Like Receptor (TLR) pathways in challenged osteoblasts. Cell viability of P. gingivalis and P. intermedia challenged osteoblasts were determined by WST assay. Changes in osteoblast morphology and inhibition of mineralization were observed by Scanning Electron Microscopy (SEM) and Von Kossa staining, respectively. Expression of TGF-β and TLR pathway genes on challenged cells were identified by RT profiler array. Both P. gingivalis and P. intermedia challenges resulted in reduced viability and mineralization of osteoblasts. Viability was reduced to 56.8% (P. gingivalis) and 52.75% (P. intermedia) at 1000 multiplicity. Amongst 48 genes examined, expressions of BMPER, SMAD1, IL8 and NFRKB were found to be highly upregulated by both bacterial challenges (Fold Change > 4). P. gingivalis and P. intermedia could play a role in implant failure by changing the expression profiles of genes related to bone formation and resorption.

Thin films of single-walled carbon nanotubes promote human osteoblastic cells (Saos-2) proliferation in low serum concentrations

International Nuclear Information System (INIS)

Akasaka, Tsukasa; Yokoyama, Atsuro; Matsuoka, Makoto; Hashimoto, Takeshi; Watari, Fumio

2010-01-01

One strategy used for the regeneration of bone is the development of cell culture substrates and scaffolds that can control osteoblast proliferation and differentiation. In recent investigations, carbon nanotubes (CNTs) have been utilized as scaffolds for osteoblastic cell cultures; however, there are only a few reports describing the proliferation of osteoblastic cells on thin CNT films; in particular, the effects of serum concentration on cell proliferation have not been studied. In the present study, we prepared culture dishes with homogeneous thin or thick films of non-modified CNTs and examined the effect of serum concentrations on human osteoblastic cells (Saos-2) proliferation in these culture dishes. We demonstrated that the ratio of cell proliferation was strongly affected by the concentration of serum. Interestingly, single-walled carbon nanotube (SWNT) thin films were found to be the most effective substrate for the proliferation of Saos-2 cells in low concentrations of serum. Thus, thin SWNT films may be used as an effective biomaterial for the culture of Saos-2 cells in low serum concentrations.

In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics

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Sun, Dao-Cai [Department of Implant Dentistry, School of Stomatology, Fourth Military Medical University, Xi' an (China); Department of Stomatology, The 291st Hospital of P.L.A, Baotou (China); Li, De-Hua [Department of Implant Dentistry, School of Stomatology, Fourth Military Medical University, Xi' an (China); Ji, Hui-Cang [Military Sanatorium of Retired Cadres, Baotou (China); Rao, Guo-Zhou [Center of Laboratory, School of Stomatology, Xi' an Jiaotong University, Xi' an (China); Liang, Li-Hua [Department of Implant Dentistry, School of Stomatology, Fourth Military Medical University, Xi' an (China); Ma, Ai-Jie [Xi' an Technology University, Xi' an (China); Xie, Chao; Zou, Gui-Ke; Song, Ying-Liang [Department of Implant Dentistry, School of Stomatology, Fourth Military Medical University, Xi' an (China)

2012-04-05

In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones.

In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics

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Sun, Dao-Cai; Li, De-Hua; Ji, Hui-Cang; Rao, Guo-Zhou; Liang, Li-Hua; Ma, Ai-Jie; Xie, Chao; Zou, Gui-Ke; Song, Ying-Liang

2012-01-01

In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones

The Impact of Metal Ion Exposure on the Cellular Behavior of Human Osteoblasts and PBMCs: In Vitro Analyses of Osteolytic Processes

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Anika Jonitz-Heincke

2017-07-01

Full Text Available Osteolysis in the periprosthetic tissue can be caused by metallic wear particles and ions that can originate from implant surface corrosion. These products influence cellular behavior and stimulate the expression of proinflammatory cytokines. The purpose of this study was to evaluate the impact of CoCr29Mo6 ions on cell survival, differentiation, and cytokine expression in human osteoblasts and peripheral blood mononuclear cells (PBMCs. Thus, we exposed cells with a mixture of 200 µg/L ion solution and determined cell viability and apoptosis/necrosis. Gene expression analyses of osteoblastic and osteoclastic differentiation markers as well as pro-osteolytic mediators (IL-6, IL-8, TNF-α, MCP-1, MMP1, TIMP1 were performed. These markers were also investigated in mixed cultures of adherent and non-adherent PBMCs as well as in co-cultures of human osteoblasts and PBMCs. The ion solution induced necrosis in osteoblasts and PBMCs in single cultures. All examined mediators were highly expressed in the co-culture of osteoblasts and PBMCs whereas in the single cell cultures only IL-6, IL-8, and MMP1 were found to be stimulated. While the applied concentration of the CoCr29Mo6 ion solutions had only marginal effects on human osteoblasts and PBMCs alone, the co-culture may provide a comprehensive model to study osteolytic processes in response to Co and Cr ions.

The Central Nervous System and Bone Metabolism: An Evolving Story.

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Dimitri, Paul; Rosen, Cliff

2017-05-01

Our understanding of the control of skeletal metabolism has undergone a dynamic shift in the last two decades, primarily driven by our understanding of energy metabolism. Evidence demonstrating that leptin not only influences bone cells directly, but that it also plays a pivotal role in controlling bone mass centrally, opened up an investigative process that has changed the way in which skeletal metabolism is now perceived. Other central regulators of bone metabolism have since been identified including neuropeptide Y (NPY), serotonin, endocannabinoids, cocaine- and amphetamine-regulated transcript (CART), adiponectin, melatonin and neuromedin U, controlling osteoblast and osteoclast differentiation, proliferation and function. The sympathetic nervous system was originally identified as the predominant efferent pathway mediating central signalling to control skeleton metabolism, in part regulated through circadian genes. More recent evidence points to a role of the parasympathetic nervous system in the control of skeletal metabolism either through muscarinic influence of sympathetic nerves in the brain or directly via nicotinic receptors on osteoclasts, thus providing evidence for broader autonomic skeletal regulation. Sensory innervation of bone has also received focus again widening our understanding of the complex neuronal regulation of bone mass. Whilst scientific advance in this field of bone metabolism has been rapid, progress is still required to understand how these model systems work in relation to the multiple confounders influencing skeletal metabolism, and the relative balance in these neuronal systems required for skeletal growth and development in childhood and maintaining skeletal integrity in adulthood.

Activity of the rat osteocalcin basal promoter in osteoblastic cells is dependent upon homeodomain and CP1 binding motifs.

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Towler, D A; Bennett, C D; Rodan, G A

1994-05-01

A detailed analysis of the transcriptional machinery responsible for osteoblast-specific gene expression should provide tools useful for understanding osteoblast commitment and differentiation. We have defined three cis-elements important for basal activity of the rat osteocalcin (OC) promoter, located at about -200 to -180, -170 to -138, and -121 to -64 relative to the transcription initiation site. A motif (TCTGATTGTGT) present in the region between -200 and -170 that binds a multisubunit CP1/NFY/CBF-like CAAT factor complex contributes significantly to high level basal activity and presumably functions as the CAAT box for the rat OC promoter. We show that the region -121 to 32 is sufficient to confer osteoblastic cell type specificity in transient transfection assays of cultured cell lines using luciferase as a reporter. The basal promoter is active in rodent osteoblastic cell lines, but not in rodent fibroblastic or muscle cell lines. Although the rat OC box (-100 to -74) contains a CAAT motif, we could not detect CP1-like CAAT factor binding to this region. In fact, we demonstrate that a Msx-1 (Hox 7.1) homeodomain binding motif (ACTAATTG; bottom strand) in the 3'-end of the rat OC box is necessary for high level activity of the rat OC basal promoter in osteoblastic cells. A nuclear factor that recognizes this motif appears to be present in osteoblastic ROS 17/2.8 cells, which produce OC, but not in fibroblastic ROS 25/1 cells, which fail to express OC. This ROS 17/2.8 nuclear factor also recognizes the A/T-rich DNA cognates of the homeodomain-containing POU family of transcription factors. Taken together, these data suggest that a ubiquitous CP1-like CAAT factor and a cell type-restricted homeodomain containing (Msx or POU family) transcription factor interact with the proximal rat OC promoter to direct appropriate basal OC transcription in osteoblastic cells.

Osteoblast response to zirconia surfaces with different topographies

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Herath, H.M.T.U. [Department of Medical Laboratory Science, Faculty of Allied Health Sciences, University of Peradeniya (Sri Lanka); Di Silvio, L. [Guy' s, King' s and St Thomas' Medical and Dental Institute, King' s College London, London SE1 9RT (United Kingdom); Evans, J.R.G., E-mail: j.r.g.evans@ucl.ac.uk [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

2015-12-01

Zirconia-3 mol% yttria ceramics were prepared with as-sintered, abraded, polished, and porous surfaces in order to explore the attachment, proliferation and differentiation of osteoblast-like cells. After modification, all surfaces were heated to 600 °C to extinguish traces of organic contamination. All surfaces supported cell attachment, proliferation and differentiation but the surfaces with grain boundary grooves or abraded grooves provided conditions for enhanced initial cell attachment. Nevertheless, overall cell proliferation and total DNA were highest on the polished surface. Zirconia sintered at a lower temperature (1300 °C vs. 1450 °C) had open porosity and presented reduced proliferation as assessed by alamarBlue™ assay, possibly because the openness of the pores prevented cells developing a local microenvironment. All cells retained the typical polygonal morphology of osteoblast-like cells with variations attributable to the underlying surface notably alignment along the grooves of the abraded surface. - Highlights: • Biocompatibility of chemically identical, topologically different ZrO{sub 2} was tested. • ZrO{sub 2} promoted cell adhesion, proliferation, differentiation and nodule formation. • Proliferation was high on polished ZrO{sub 2} but initial recruitment was high on abraded ZrO{sub 2}. • With open porosity, proliferation was low; cells cannot establish a microenvironment.

Normal hematopoiesis and lack of β-catenin activation in osteoblasts of patients and mice harboring Lrp5 gain-of-function mutations.

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Galán-Díez, Marta; Isa, Adiba; Ponzetti, Marco; Nielsen, Morten Frost; Kassem, Moustapha; Kousteni, Stavroula

2016-03-01

Osteoblasts are emerging regulators of myeloid malignancies since genetic alterations in them, such as constitutive activation of β-catenin, instigate their appearance. The LDL receptor-related protein 5 (LRP5), initially proposed to be a co-receptor for Wnt proteins, in fact favors bone formation by suppressing gut-serotonin synthesis. This function of Lrp5 occurring in the gut is independent of β-catenin activation in osteoblasts. However, it is unknown whether Lrp5 can act directly in osteoblast to influence other functions that require β-catenin signaling, particularly, the deregulation of hematopoiesis and leukemogenic properties of β-catenin activation in osteoblasts, that lead to development of acute myeloid leukemia (AML). Using mice with gain-of-function (GOF) Lrp5 alleles (Lrp5(A214V)) that recapitulate the human high bone mass (HBM) phenotype, as well as patients with the T253I HBM Lrp5 mutation, we show here that Lrp5 GOF mutations in both humans and mice do not activate β-catenin signaling in osteoblasts. Consistent with a lack of β-catenin activation in their osteoblasts, Lrp5(A214V) mice have normal trilinear hematopoiesis. In contrast to leukemic mice with constitutive activation of β-catenin in osteoblasts (Ctnnb1(CAosb)), accumulation of early myeloid progenitors, a characteristic of AML, myeloid-blasts in blood, and segmented neutrophils or dysplastic megakaryocytes in the bone marrow, are not observed in Lrp5(A214V) mice. Likewise, peripheral blood count analysis in HBM patients showed normal hematopoiesis, normal percentage of myeloid cells, and lack of anemia. We conclude that Lrp5 GOF mutations do not activate β-catenin signaling in osteoblasts. As a result, myeloid lineage differentiation is normal in HBM patients and mice. This article is part of a Special Issue entitled: Tumor Microenvironment Regulation of Cancer Cell Survival, Metastasis, Inflammation, and Immune Surveillance edited by Peter Ruvolo and Gregg L. Semenza. Published

Osteocalcin, a marker of differentiated function during calcification of cultured chick osteoblasts

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Lian, J.; Chipman, S.; Glowacki, J.; Gerstenfeld, L.

1986-01-01

The expression of differentiated function was examined in cultured osteoblasts isolated from 17-day embryonic chicken calvarie. Cell cultures grown in the absence (control) or presence of 10 mM β-Glycerol Phosphate (βGP) (stimulus for calcification) were analyzed at 6-day intervals over a 30-day period for total mineral, alkaline phosphatase (AP) activity, osteocalcin levels and collagen. AP was first detected in both cultures between days 6 and 9 when cells became crowded. Control cultures maintained high levels of enzyme activity (30-50 fold) while β GPO 4 culture activity declined after day 18 when extensive mineralization occurred. Osteocalcin, the vitamin K-dependent, bone-specific, calcium-binding protein showed a similar pattern of induction as AP with at 50-100-fold increase in both cultures. Collagen accumulated through out the 30-day experimental period for both β GPO 4 and control cultures while collagen synthesis ( 3 H-proline pulse) peaked at day 15 in culture. These results suggest that with time in culture, osteoblast differentiation may be occurring. The increased mineralization of β GPO 4 cultures appeared to down regulate the enzyme activity of AP in comparison to control culture, while osteocalcin synthesis was enhanced. In conclusion, the chick osteoblast system offers a model to study bone cell differentiation, protein synthesis and matrix calcification

Osteomacs interact with megakaryocytes and osteoblasts to regulate murine hematopoietic stem cell function.

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Mohamad, Safa F; Xu, Linlin; Ghosh, Joydeep; Childress, Paul J; Abeysekera, Irushi; Himes, Evan R; Wu, Hao; Alvarez, Marta B; Davis, Korbin M; Aguilar-Perez, Alexandra; Hong, Jung Min; Bruzzaniti, Angela; Kacena, Melissa A; Srour, Edward F

2017-12-12

Networking between hematopoietic stem cells (HSCs) and cells of the hematopoietic niche is critical for stem cell function and maintenance of the stem cell pool. We characterized calvariae-resident osteomacs (OMs) and their interaction with megakaryocytes to sustain HSC function and identified distinguishing properties between OMs and bone marrow (BM)-derived macrophages. OMs, identified as CD45 + F4/80 + cells, were easily detectable (3%-5%) in neonatal calvarial cells. Coculture of neonatal calvarial cells with megakaryocytes for 7 days increased OM three- to sixfold, demonstrating that megakaryocytes regulate OM proliferation. OMs were required for the hematopoiesis-enhancing activity of osteoblasts, and this activity was augmented by megakaryocytes. Serial transplantation demonstrated that HSC repopulating potential was best maintained by in vitro cultures containing osteoblasts, OMs, and megakaryocytes. With or without megakaryocytes, BM-derived macrophages were unable to functionally substitute for neonatal calvarial cell-associated OMs. In addition, OMs differentiated into multinucleated, tartrate resistant acid phosphatase-positive osteoclasts capable of bone resorption. Nine-color flow cytometric analysis revealed that although BM-derived macrophages and OMs share many cell surface phenotypic similarities (CD45, F4/80, CD68, CD11b, Mac2, and Gr-1), only a subgroup of OMs coexpressed M-CSFR and CD166, thus providing a unique profile for OMs. CD169 was expressed by both OMs and BM-derived macrophages and therefore was not a distinguishing marker between these 2 cell types. These results demonstrate that OMs support HSC function and illustrate that megakaryocytes significantly augment the synergistic activity of osteoblasts and OMs. Furthermore, this report establishes for the first time that the crosstalk between OMs, osteoblasts, and megakaryocytes is a novel network supporting HSC function.

Increased osteoblast density in the presence of novel calcium phosphate coated magnetic nanoparticles

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Pareta, Rajesh A; Webster, Thomas J; Taylor, Erik

2008-01-01

Bone diseases (including osteoporosis, osteoarthritis and bone cancer) are of great concern to the medical world. Drugs are available to treat such diseases, but often these drugs are not specifically targeted to the site of the disease and, thus, lack an immediate directed therapeutic effect. The optimal drug delivery system should enhance healthy bone growth with high specificity to the site of bone disease. It has been previously shown that magnetic nanoparticles can be directed in the presence of a magnetic field to any part of the body, allowing for site-specific drug delivery and possibly an immediate increase in bone density. The objective of the present study was to build off of this evidence and determine the density of osteoblasts (bone forming cells) in the presence of various uncoated and coated magnetic nanoparticles that could eventually be used in drug delivery applications. Results showed that some magnetic nanoparticles (specifically, γ-Fe 2 O 3 ) significantly promoted osteoblast density (that is, cells per well) after 5 and 8 days of culture compared to controls (no particles). These magnetic nanoparticles were further coated with calcium phosphate (CaP; the main inorganic component of bone) to tailor them for treating various bone diseases. The coatings were conducted in the presence of either bovine serum albumin (BSA) or citric acid (CA) to reduce magnetic nanoparticle agglomeration, a common problem resulting from the use of nanoparticles which decreases their effectiveness. Results with these coatings showed that magnetic nanoparticles, specifically (γ-Fe 2 O 3 ), coated in the presence of BSA significantly increased osteoblast density compared to controls after 1 day. In this manner, this study provided unexpected evidence that CaP-coated γ-Fe 2 O 3 magnetic nanoparticles increased osteoblast density (compared to no particles) and, thus, should be further studied to treat numerous bone diseases

Leptin promotes osteoblast differentiation and mineralization of primary cultures of vascular smooth muscle cells by inhibiting glycogen synthase kinase (GSK)-3{beta}

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Zeadin, Melec G.; Butcher, Martin K.; Shaughnessy, Stephen G. [Department of Medicine, McMaster University, Hamilton, ON (Canada); Thrombosis and Atherosclerosis Research Institute, Hamilton, ON (Canada); Werstuck, Geoff H., E-mail: Geoff.Werstuck@taari.ca [Department of Medicine, McMaster University, Hamilton, ON (Canada); Thrombosis and Atherosclerosis Research Institute, Hamilton, ON (Canada)

2012-09-07

Highlights: Black-Right-Pointing-Pointer Leptin promotes osteoblast differentiation of primary smooth muscle cells. Black-Right-Pointing-Pointer Leptin regulates the expression of genes involved in osteoblast differentiation. Black-Right-Pointing-Pointer Constitutively active GSK-3{beta} attenuates leptin-induced osteoblast differentiation. Black-Right-Pointing-Pointer This suggests that leptin signals through GSK-3{beta} to promote osteoblast differentiation. -- Abstract: In this study, we begin to investigate the underlying mechanism of leptin-induced vascular calcification. We found that treatment of cultured bovine aortic smooth muscle cells (BASMCs) with leptin (0.5-4 {mu}g/ml) induced osteoblast differentiation in a dose-dependent manner. Furthermore, we found that leptin significantly increased the mRNA expression of osteopontin and bone sialoprotein, while down-regulating matrix gla protein (MGP) expression in BASMCs. Key factors implicated in osteoblast differentiation, including members of the Wnt signaling pathway, were examined. Exposure to leptin enhanced phosphorylation of GSK-3{beta} on serine-9 thereby inhibiting activity and promoting the nuclear accumulation of {beta}-catenin. Transfection of BASMCs with an adenovirus that expressed constitutively active GSK-3{beta} (Ad-GSK-3{beta} S9A) resulted in a >2-fold increase in GSK-3{beta} activity and a significant decrease in leptin-induced alkaline phosphatase (ALP) activity. In addition, qRT-PCR analysis showed that GSK-3{beta} activation resulted in a significant decrease in the expression of osteopontin and bone sialoprotein, but a marked increase in MGP mRNA expression. When taken together, our results suggest a mechanism by which leptin promotes osteoblast differentiation and vascular calcification in vivo.

Porphyromonas gingivalis decreases osteoblast proliferation through IL-6-RANKL/OPG and MMP-9/TIMPs pathways

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Le Xuan

2009-01-01

Full Text Available Background: Porphyromonas gingivalis, an important periodontal pathogen, is closely associated with inflammatory alveolar bone resorption. This bacterium exerts its pathogenic effect indirectly through multiple virulence factors, such as lipopolysaccharides, fimbriae, and proteases. Another possible pathogenic path may be through a direct interaction with the host′s soft and hard tissues (e.g., alveolar bone, which could lead to periodontitis. Aims and Objectives: The aim of the present study was to investigate the direct effect of live and heat-inactivated P gingivalis on bone resorption, using an in vitro osteoblast culture model. Results: Optical microscopy and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide MTT assay revealed that live P gingivalis induced osteoblast detachment and reduced their proliferation. This effect was specific to live bacteria and was dependent on their concentration. Live P gingivalis increased IL-6 mRNA expression and protein production and downregulated RANKL and OPG mRNA expression. The effect of live P gingivalis on bone resorption was strengthened by an increase in MMP-9 expression and its activity. This increase was accompanied by an increase in TIMP-1 and TIMP-2 mRNA expression and protein production by osteoblasts infected with live P gingivalis. Conclusion: Overall, the results suggest that direct contact of P gingivalis with osteoblasts induces bone resorption through an inflammatory pathway that involves IL-6, RANKL/OPG, and MMP-9/TIMPs.

Four-point bending protocols to study the effects of dynamic strain in osteoblastic cells in vitro.

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Galea, Gabriel L; Price, Joanna S

2015-01-01

Strain engendered within bone tissue by mechanical loading of the skeleton is a major influence on the processes of bone modeling and remodeling and so a critical determinant of bone mass and architecture. The cells best placed to respond to strain in bone tissue are the resident osteocytes and osteoblasts. To address the mechanisms of strain-related responses in osteoblast-like cells, our group uses both in vivo and in vitro approaches, including a system of four-point bending of the substrate on which cells are cultured. A range of cell lines can be studied using this system but we routinely compare their responses to those in primary cultures of osteoblast-like cells derived from explants of mouse long bones. These cells show a range of well-characterized responses to physiological levels of strain, including increased proliferation, which in vivo is a feature of the osteogenic response.

Non-enzymatic glycosylation of a type I collagen matrix: effects on osteoblastic development and oxidative stress

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Barrio Daniel A

2001-08-01

Full Text Available Abstract Background The tissue accumulation of protein-bound advanced glycation endproducts (AGE may be involved in the etiology of diabetic chronic complications, including osteopenia. The aim of this study was to investigate the effect of an AGE-modified type I collagen substratum on the adhesion, spreading, proliferation and differentiation of rat osteosarcoma UMR106 and mouse non-transformed MC3T3E1 osteoblastic cells. We also studied the role of reactive oxygen species (ROS and nitric oxide synthase (NOS expression on these AGE-collagen mediated effects. Results AGE-collagen decreased the adhesion of UMR106 cells, but had no effect on the attachment of MC3T3E1 cells. In the UMR106 cell line, AGE-collagen also inhibited cellular proliferation, spreading and alkaline phosphatase (ALP activity. In preosteoblastic MC3T3E1 cells (24-hour culture, proliferation and spreading were significantly increased by AGE-collagen. After one week of culture (differentiated MC3T3E1 osteoblasts AGE-collagen inhibited ALP activity, but had no effect on cell number. In mineralizing MC3T3E1 cells (3-week culture AGE-collagen induced a decrease in the number of surviving cells and of extracellular nodules of mineralization, without modifying their ALP activity. Intracellular ROS production, measured after a 48-hour culture, was decreased by AGE-collagen in MC3T3E1 cells, but was increased by AGE-collagen in UMR106 cells. After a 24-hour culture, AGE-collagen increased the expression of endothelial and inducible NOS, in both osteoblastic cell lines. Conclusions These results suggest that the accumulation of AGE on bone extracellular matrix could regulate the proliferation and differentiation of osteoblastic cells. These effects appear to depend on the stage of osteoblastic development, and possibly involve the modulation of NOS expression and intracellular ROS pathways.

Effect of acetaminophen on osteoblastic differentiation and migration of MC3T3-E1 cells.

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Nakatsu, Yoshihiro; Nakagawa, Fumio; Higashi, Sen; Ohsumi, Tomoko; Shiiba, Shunji; Watanabe, Seiji; Takeuchi, Hiroshi

2018-02-01

N-acetyl-p-aminophenol (APAP, acetaminophen, paracetamol) is a widely used analgesic/antipyretic with weak inhibitory effects on cyclooxygenase (COX) compared to non-steroidal anti-inflammatory drugs (NSAIDs). The mechanism of action of APAP is mediated by its metabolite that activates transient receptor potential channels, including transient receptor potential vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) or the cannabinoid receptor type 1 (CB1). However, the exact molecular mechanism and target underlying the cellular actions of APAP remain unclear. Therefore, we investigated the effect of APAP on osteoblastic differentiation and cell migration, with a particular focus on TRP channels and CB1. Effects of APAP on osteoblastic differentiation and cell migration of MC3T3-E1, a mouse pre-osteoblast cell line, were assessed by the increase in alkaline phosphatase (ALP) activity, and both wound-healing and transwell-migration assays, respectively. APAP dose-dependently inhibited osteoblastic differentiation, which was well correlated with the effects on COX activity compared with other NSAIDs. In contrast, cell migration was promoted by APAP, and this effect was not correlated with COX inhibition. None of the agonists or antagonists of TRP channels and the CB receptor affected the APAP-induced cell migration, while the effect of APAP on cell migration was abolished by down-regulating TRPV4 gene expression. APAP inhibited osteoblastic differentiation via COX inactivation while it promoted cell migration independently of previously known targets such as COX, TRPV1, TRPA1 channels, and CB receptors, but through the mechanism involving TRPV4. APAP may have still unidentified molecular targets that modify cellular functions. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier B.V. All rights reserved.

An osteoblast-derived proteinase controls tumor cell survival via TGF-beta activation in the bone microenvironment.

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Thiolloy, Sophie; Edwards, James R; Fingleton, Barbara; Rifkin, Daniel B; Matrisian, Lynn M; Lynch, Conor C

2012-01-01

Breast to bone metastases frequently induce a "vicious cycle" in which osteoclast mediated bone resorption and proteolysis results in the release of bone matrix sequestered factors that drive tumor growth. While osteoclasts express numerous proteinases, analysis of human breast to bone metastases unexpectedly revealed that bone forming osteoblasts were consistently positive for the proteinase, MMP-2. Given the role of MMP-2 in extracellular matrix degradation and growth factor/cytokine processing, we tested whether osteoblast derived MMP-2 contributed to the vicious cycle of tumor progression in the bone microenvironment. To test our hypothesis, we utilized murine models of the osteolytic tumor-bone microenvironment in immunocompetent wild type and MMP-2 null mice. In longitudinal studies, we found that host MMP-2 significantly contributed to tumor progression in bone by protecting against apoptosis and promoting cancer cell survival (caspase-3; immunohistochemistry). Our data also indicate that host MMP-2 contributes to tumor induced osteolysis (μCT, histomorphometry). Further ex vivo/in vitro experiments with wild type and MMP-2 null osteoclast and osteoblast cultures identified that 1) the absence of MMP-2 did not have a deleterious effect on osteoclast function (cd11B isolation, osteoclast differentiation, transwell migration and dentin resorption assay); and 2) that osteoblast derived MMP-2 promoted tumor survival by regulating the bioavailability of TGFβ, a factor critical for cell-cell communication in the bone (ELISA, immunoblot assay, clonal and soft agar assays). Collectively, these studies identify a novel "mini-vicious cycle" between the osteoblast and metastatic cancer cells that is key for initial tumor survival in the bone microenvironment. In conclusion, the findings of our study suggest that the targeted inhibition of MMP-2 and/or TGFβ would be beneficial for the treatment of bone metastases.

An osteoblast-derived proteinase controls tumor cell survival via TGF-beta activation in the bone microenvironment.

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Sophie Thiolloy

Full Text Available Breast to bone metastases frequently induce a "vicious cycle" in which osteoclast mediated bone resorption and proteolysis results in the release of bone matrix sequestered factors that drive tumor growth. While osteoclasts express numerous proteinases, analysis of human breast to bone metastases unexpectedly revealed that bone forming osteoblasts were consistently positive for the proteinase, MMP-2. Given the role of MMP-2 in extracellular matrix degradation and growth factor/cytokine processing, we tested whether osteoblast derived MMP-2 contributed to the vicious cycle of tumor progression in the bone microenvironment.To test our hypothesis, we utilized murine models of the osteolytic tumor-bone microenvironment in immunocompetent wild type and MMP-2 null mice. In longitudinal studies, we found that host MMP-2 significantly contributed to tumor progression in bone by protecting against apoptosis and promoting cancer cell survival (caspase-3; immunohistochemistry. Our data also indicate that host MMP-2 contributes to tumor induced osteolysis (μCT, histomorphometry. Further ex vivo/in vitro experiments with wild type and MMP-2 null osteoclast and osteoblast cultures identified that 1 the absence of MMP-2 did not have a deleterious effect on osteoclast function (cd11B isolation, osteoclast differentiation, transwell migration and dentin resorption assay; and 2 that osteoblast derived MMP-2 promoted tumor survival by regulating the bioavailability of TGFβ, a factor critical for cell-cell communication in the bone (ELISA, immunoblot assay, clonal and soft agar assays.Collectively, these studies identify a novel "mini-vicious cycle" between the osteoblast and metastatic cancer cells that is key for initial tumor survival in the bone microenvironment. In conclusion, the findings of our study suggest that the targeted inhibition of MMP-2 and/or TGFβ would be beneficial for the treatment of bone metastases.

Mechanisms involved in regulation of osteoclastic differentiation by mechanical stress-loaded osteoblasts

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Kaneuji, Takeshi; Ariyoshi, Wataru; Okinaga, Toshinori; Toshinaga, Akihiro; Takahashi, Tetsu; Nishihara, Tatsuji

2011-01-01

Highlights: → Effect of compressive force on osteoblasts were examined. → Compressive force induced OPG expression and suppressed osteoclastogenesis. → This enhancement of OPG is dependent on Wnt/Ca2+ signal pathway. -- Abstract: Mechanical stress is known to be important for regulation of bone turnover, though the detailed mechanisms are not fully understood. In the present study, we examined the effect of mechanical stress on osteoblasts using a novel compression model. Mouse osteoblastic MC3T3-E1 cells were embedded in three-dimensional (3D) gels and cultured with continuous compressive force (0-10.0 g/cm 2 ) for 48 h, and the conditioned medium were collected. RAW264.7 cells were then incubated with the conditioned medium for various times in the presence of receptor activator of nuclear factor-κB ligand (RANKL). Conditioned medium was found to inhibit the differentiation of RAW264.7 cells into osteoclasts induced by RANKL via down-regulation of the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), phosphorylation of IκBα, and nuclear translocation of p50 and p65. Interestingly, the conditioned medium also had a high level of binding activity to RANKL and blocked the binding of RANK to RANKL. Furthermore, the binding activity of conditioned medium to RANKL was reduced when the 3D gel was supplemented with KN-93, an inhibitor of non-canonical Wnt/Ca 2+ pathway. In addition, expression level of osteoprotegerin (OPG) mRNA was increased in time- and force-dependent manners, and remarkably suppressed by KN-93. These results indicate that osteoblastic cells subjected to mechanical stress produce OPG, which binds to RANKL. Furthermore, this binding activity strongly inhibited osteoclastogenesis through suppression of TRAF6 and the nuclear factor-kappa B (NF-κB) signaling pathway, suggesting that enhancement of OPG expression induced by mechanical stress is dependent on non-canonical Wnt/Ca 2+ pathway.

Mechanisms involved in regulation of osteoclastic differentiation by mechanical stress-loaded osteoblasts

Energy Technology Data Exchange (ETDEWEB)

Kaneuji, Takeshi [Division of Oral and Maxillofacial Reconstructive Surgery, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Ariyoshi, Wataru; Okinaga, Toshinori; Toshinaga, Akihiro [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Takahashi, Tetsu [Division of Oral and Maxillofacial Reconstructive Surgery, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Nishihara, Tatsuji, E-mail: tatsujin@kyu-dent.ac.jp [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan)

2011-04-29

Highlights: {yields} Effect of compressive force on osteoblasts were examined. {yields} Compressive force induced OPG expression and suppressed osteoclastogenesis. {yields} This enhancement of OPG is dependent on Wnt/Ca2+ signal pathway. -- Abstract: Mechanical stress is known to be important for regulation of bone turnover, though the detailed mechanisms are not fully understood. In the present study, we examined the effect of mechanical stress on osteoblasts using a novel compression model. Mouse osteoblastic MC3T3-E1 cells were embedded in three-dimensional (3D) gels and cultured with continuous compressive force (0-10.0 g/cm{sup 2}) for 48 h, and the conditioned medium were collected. RAW264.7 cells were then incubated with the conditioned medium for various times in the presence of receptor activator of nuclear factor-{kappa}B ligand (RANKL). Conditioned medium was found to inhibit the differentiation of RAW264.7 cells into osteoclasts induced by RANKL via down-regulation of the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), phosphorylation of I{kappa}B{alpha}, and nuclear translocation of p50 and p65. Interestingly, the conditioned medium also had a high level of binding activity to RANKL and blocked the binding of RANK to RANKL. Furthermore, the binding activity of conditioned medium to RANKL was reduced when the 3D gel was supplemented with KN-93, an inhibitor of non-canonical Wnt/Ca{sup 2+} pathway. In addition, expression level of osteoprotegerin (OPG) mRNA was increased in time- and force-dependent manners, and remarkably suppressed by KN-93. These results indicate that osteoblastic cells subjected to mechanical stress produce OPG, which binds to RANKL. Furthermore, this binding activity strongly inhibited osteoclastogenesis through suppression of TRAF6 and the nuclear factor-kappa B (NF-{kappa}B) signaling pathway, suggesting that enhancement of OPG expression induced by mechanical stress is dependent on non-canonical Wnt

Culture conditions for equine bone marrow mesenchymal stem cells and expression of key transcription factors during their differentiation into osteoblasts

Science.gov (United States)

2013-01-01

Background The use of equine bone marrow mesenchymal stem cells (BMSC) is a novel method to improve fracture healing in horses. However, additional research is needed to identify optimal culture conditions and to determine the mechanisms involved in regulating BMSC differentiation into osteoblasts. The objectives of the experiments were to determine: 1) if autologous or commercial serum is better for proliferation and differentiation of equine BMSC into osteoblasts, and 2) the expression of key transcription factors during the differentiation of equine BMSC into osteoblasts. Equine BMSC were isolated from the sterna of 3 horses, treated with purchased fetal bovine serum (FBS) or autologous horse serum (HS), and cell proliferation determined. To induce osteoblast differentiation, cells were incubated with L-ascorbic acid-2-phosphate and glycerol-2-phosphate in the presence or absence of human bone morphogenetic protein2 (BMP2), dexamethasone (DEX), or combination of the two. Alkaline phosphatase (ALP) activity, a marker of osteoblast differentiation, was determined by ELISA. Total RNA was isolated from differentiating BMSC between d 0 to 18 to determine expression of runt-related transcription factor2 (Runx2), osterix (Osx), and T-box3 (Tbx3). Data were analyzed by ANOVA. Results Relative to control, FBS and HS increased cell number (133 ± 5 and 116 ± 5%, respectively; P  0.8). Runt-related transcription factor2 expression increased 3-fold (P equine BMSC into osteoblasts. In addition, expression of Runx2 and osterix increased and expression of Tbx3 is reduced during differentiation. PMID:24169030

Sumoylation of the Tumor Suppressor Promyelocytic Leukemia Protein Regulates Arsenic Trioxide-Induced Collagen Synthesis in Osteoblasts.

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Xu, Wen-Xiao; Liu, Sheng-Zhi; Wu, Di; Qiao, Guo-Fen; Yan, Jinglong

2015-01-01

Promyelocytic leukemia (PML) protein is a tumor suppressor that fuses with retinoic acid receptor-α (PML-RARα) to contribute to the initiation of acute promyelocytic leukemia (APL). Arsenic trioxide (ATO) upregulates expression of TGF-β1, promoting collagen synthesis in osteoblasts, and ATO binds directly to PML to induce oligomerization, sumoylation, and ubiquitination. However, how ATO upregulates TGF-β1 expression is uncertain. Thus, we suggested that PML sumoylation is responsible for regulation of TGF-β1 protein expression. Kunming mice were treated with ATO, and osteoblasts were counted under scanning electron microscopy. Masson's staining was used to quantify collagen content. hFOB1.19 cells were transfected with siRNA against UBC9 or RNF4, and then treated with ATO or FBS. TGF-β1, PML expression, and sumoylation were quantified with Western blot, and collagen quantified via immunocytochemistry. ATO enhanced osteoblast accumulation, collagen synthesis, and PML-NB formation in vivo. Knocking down UBC9 in hFOB1.19 cells inhibited ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. Conversely, knocking down RNF4 enhanced ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. These data suggest that PML sumoylation is required for ATO-induced collagen synthesis in osteoblasts. © 2015 S. Karger AG, Basel.

Targeting of Mesenchymal Stromal Cells by Cre-Recombinase Transgenes Commonly Used to Target Osteoblast Lineage Cells.

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Zhang, Jingzhu; Link, Daniel C

2016-11-01

The targeting specificity of tissue-specific Cre-recombinase transgenes is a key to interpreting phenotypes associated with their use. The Ocn-Cre and Dmp1-Cre transgenes are widely used to target osteoblasts and osteocytes, respectively. Here, we used high-resolution microscopy of bone sections and flow cytometry to carefully define the targeting specificity of these transgenes. These transgenes were crossed with Cxcl12 gfp mice to identify Cxcl12-abundant reticular (CAR) cells, which are a perivascular mesenchymal stromal population implicated in hematopoietic stem/progenitor cell maintenance. We show that in addition to osteoblasts, Ocn-Cre targets a majority of CAR cells and arteriolar pericytes. Surprisingly, Dmp1-Cre also targets a subset of CAR cells, in which expression of osteoblast-lineage genes is enriched. Finally, we introduce a new tissue-specific Cre-recombinase, Tagln-Cre, which efficiently targets osteoblasts, a majority of CAR cells, and both venous sinusoidal and arteriolar pericytes. These data show that Ocn-Cre and Dmp1-Cre target broader stromal cell populations than previously appreciated and may aid in the design of future studies. Moreover, these data highlight the heterogeneity of mesenchymal stromal cells in the bone marrow and provide tools to interrogate this heterogeneity. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

Chronic alcohol abuse and endosseous implants: Linkage of in vitro osteoblast dysfunction to titanium osseointegration rate

International Nuclear Information System (INIS)

Torricelli, Paola; Fini, Milena; Giavaresi, Gianluca; Rimondini, Lia; Tschon, Matilde; Rimondini, Roberto; Carrassi, Antonio; Giardino, Roberto

2008-01-01

Chronic alcohol consumption is associated with pathological effects on bone, and it is correlated with the increasing risk of osteoporosis and fractures. The negative effects of alcohol intake also influence bone repair processes and the osseointegration of implants. The aim of the present in vitro study was to investigate the proliferation and synthetic activity of osteoblasts isolated from the trabecular bone of rats previously exposed to 7-week intermittent exposure to ethanol vapour (EE-OB), and sham-aged rats (SA-OB), when cultured on standard commercially pure Ti (cpTi). Osteoblast proliferation (WST-1), alkaline phosphatase (ALP), osteocalcin (OC), collagen type I (CICP), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and transforming growth factor-β1 (TGF-β1) were measured at 1, 7, and 14 days of culture. Our results showed a decrease in the cell viability and synthetic activity of osteoblasts exposed to ethanol when cultured on cpTi. Moreover, the release of local regulatory factors from osteoblasts was imbalanced: TGF-β1 production was reduced and TNF-α and IL-6 were up-regulated. These in vitro data suggest that alcohol abuse affects bone repair and decreases the ability to form bone around standard cpTi. Innovative surfaces and adjuvant therapies could be useful when implants are required in alcoholics

[Impact of different degree pulpitis on cell proliferation and osteoblastic differentiation of dental pulp stem cell in Beagle immature premolars].

Science.gov (United States)

Ling, L; Zhao, Y M; Ge, L H

2016-10-18

To compare the proliferation and osteoblastic differentiation of dental pulp stem cell (DPSC) isolated from normal and inflamed pulps of different degrees in Beagle immature premolars, and provide evidence for the use of inflammatory DPSC (IDPSC). This study evaluated 14 Beagle's young premolars (21 roots). In the experiment group, irreversible pulpitis was induced by pulp exposure and the inflamed pulps were extracted 2 weeks and 6 weeks after the pulp chamber opening.For the control group, normal pulps were extracted immediately after the exposure. HE staining and real-time PCR were performed to confirm the inflammation. The cells were isolated from the inflamed and normal pulps (IDPSC and DPSC). Cell proliferation and osteoblastic differentiation potentials of the two cells were compared. Inflammation cells infiltration was observed in the inflamed pulps by HE staining. The expression of inflammatory factor was much higher in the 6 week inflamed pulp. IDPSC had higher potential of cell proliferation and osteoblastic differentiation potentials. Furthermore, the osteoblastic differentiation potentials of IDPSC from 2 week inflamed pulp were higher than those from 6 week inflamed pulp. The potential of cell proliferation and osteoblastic differentiation of DPSC was enhanced at early stage of irreversible pulpitis, and reduced at late stage in Beagle immature premolars.

Tailoring nanocrystalline diamond coated on titanium for osteoblast adhesion.

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Pareta, Rajesh; Yang, Lei; Kothari, Abhishek; Sirinrath, Sirivisoot; Xiao, Xingcheng; Sheldon, Brian W; Webster, Thomas J

2010-10-01

Diamond coatings with superior chemical stability, antiwear, and cytocompatibility properties have been considered for lengthening the lifetime of metallic orthopedic implants for over a decade. In this study, an attempt to tailor the surface properties of diamond films on titanium to promote osteoblast (bone forming cell) adhesion was reported. The surface properties investigated here included the size of diamond surface features, topography, wettability, and surface chemistry, all of which were controlled during microwave plasma enhanced chemical-vapor-deposition (MPCVD) processes using CH4-Ar-H2 gas mixtures. The hardness and elastic modulus of the diamond films were also determined. H2 concentration in the plasma was altered to control the crystallinity, grain size, and topography of the diamond coatings, and specific plasma gases (O2 and NH3) were introduced to change the surface chemistry of the diamond coatings. To understand the impact of the altered surface properties on osteoblast responses, cell adhesion tests were performed on the various diamond-coated titanium. The results revealed that nanocrystalline diamond (grain sizes diamond and, thus, should be further studied for improving orthopedic applications. Copyright 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

The effect of oscillatory mechanical stimulation on osteoblast attachment and proliferation

International Nuclear Information System (INIS)

Aryaei, Ashkan; Jayasuriya, Ambalangodage C.

2015-01-01

The aim of this paper is to investigate the effect of the magnitude and duration of oscillatory mechanical stimulation on osteoblast attachment and proliferation as well as the time gap between seeding and applying the stimulation. Cells were exposed to three levels of speed at two different conditions. For the first group, mechanical shear stress was applied after 20 min of cell seeding. For the second group there was no time gap between cell seeding and applying mechanical stimulation. The total area subjected to shear stress was divided into three parts and for each part a comparative study was conducted at defined time points. Our results showed that both shear stress magnitude and the time gap between cell seeding and applying shear stress, are important in further cell proliferation and attachment. The effect of shear stress was not significant at lower speeds for both groups at earlier time points. However, a higher percentage of area was covered by cells at later time points under shear stress. In addition, the time gap can also improve osteoblast attachment. For the best rate of cell attachment and proliferation, the magnitude of shear stress and time gap should be optimized. The results of this paper can be utilized to improve cell attachment and proliferation in bioreactors. - Highlights: • The effect of oscillatory mechanical stimulation on osteoblast functions was studied. • Cells were exposed at three levels of speed to attach cells. • Shear stress magnitude and time gap are important for cell functions. • Cells start developing extracellular components at the early stage of seeding

Cooperative effects in differentiation and proliferation between PDGF-BB and matrix derived synthetic peptides in human osteoblasts

Directory of Open Access Journals (Sweden)

Vordemvenne Thomas

2011-11-01

Full Text Available Abstract Background Enhancing osteogenic capabilities of bone matrix for the treatment of fractures and segmental defects using growth factors is an active area of research. Recently, synthetic peptides like AC- 100, TP508 or p-15 corresponding to biologically active sequences of matrix proteins have been proven to stimulate bone formation. The platelet-derived growth factor (PDGF BB has been identified as an important paracrine factor in early bone healing. We hypothesized that the combined use of PDGF-BB with synthetic peptides could result in an increase in proliferation and calcification of osteoblast-like cells. Methods Osteoblast-like cell cultures were treated with PDGF and synthetic peptides, singly and as combinations, and compared to non-treated control cell cultures. The cultures were evaluated at days 2, 5, and 10 in terms of cell proliferation, calcification and gene expression of alkaline phosphate, collagen I and osteocalcin. Results Experimental findings revealed that the addition of PDGF, p-15 and TP508 and combinations of PDGF/AC-100, PDGF/p-15 and PDGF/TP508 resulted in an increase in proliferating osteoblasts, especially in the first 5 days of cultivation. Proliferation did not significantly differ between single factors and factor combinations (p > 0.05. The onset of calcification in osteoblasts occurred earlier and was more distinct compared to the corresponding control or PDGF stimulation alone. Significant difference was found for the combined use of PDGF/p-15 and PDGF/AC-100 (p Conclusions Our findings indicate that PDGF exhibits cooperative effects with synthetic peptides in differentiation and proliferation. These cooperative effects cause a significant early calcification of osteoblast-like cells (p

Production and action of transforming growth factor-beta in human osteoblast cultures: dependence on cell differentiation and modulation by calcitriol

DEFF Research Database (Denmark)

Kassem, M; Kveiborg, Marie; Eriksen, E F

2000-01-01

Transforming growth factor beta (TGF-beta) plays an important role in skeletal remodelling. However, few studies have examined its effects on cultured human osteoblasts. Our aim is to characterise the biological effects of TGF-beta1 on human osteoblasts and to examine the interaction between TGF-...

Megakaryocytes promote murine osteoblastic HSC niche expansion and stem cell engraftment after radioablative conditioning.

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Olson, Timothy S; Caselli, Anna; Otsuru, Satoru; Hofmann, Ted J; Williams, Richard; Paolucci, Paolo; Dominici, Massimo; Horwitz, Edwin M

2013-06-27

Successful hematopoietic stem cell (HSC) transplantation requires donor HSC engraftment within specialized bone marrow microenvironments known as HSC niches. We have previously reported a profound remodeling of the endosteal osteoblastic HSC niche after total body irradiation (TBI), defined as relocalization of surviving megakaryocytes to the niche site and marked expansion of endosteal osteoblasts. We now demonstrate that host megakaryocytes function critically in expansion of the endosteal niche after preparative radioablation and in the engraftment of donor HSC. We show that TBI-induced migration of megakaryocytes to the endosteal niche depends on thrombopoietin signaling through the c-MPL receptor on megakaryocytes, as well as CD41 integrin-mediated adhesion. Moreover, niche osteoblast proliferation post-TBI required megakaryocyte-secreted platelet-derived growth factor-BB. Furthermore, blockade of c-MPL-dependent megakaryocyte migration and function after TBI resulted in a significant decrease in donor HSC engraftment in primary and competitive secondary transplantation assays. Finally, we administered thrombopoietin to mice beginning 5 days before marrow radioablation and ending 24 hours before transplant to enhance megakaryocyte function post-TBI, and found that this strategy significantly enhanced donor HSC engraftment, providing a rationale for improving hematopoietic recovery and perhaps overall outcome after clinical HSC transplantation.

Vertically aligned carbon nanotubes as cytocompatible material for enhanced adhesion and proliferation of osteoblast-like cells.

Science.gov (United States)

Giannona, Suna; Firkowska, Izabela; Rojas-Chapana, José; Giersig, Michael

2007-01-01

In this study, we describe the spatial organization of CAL-72 osteoblast-like cells on arrays of vertically aligned multi-walled carbon nanotubes (VACNTs). It was observed that, unlike cell growth on non-patterned surfaces, the cell attachment and spreading process on VACNTs was significantly enhanced. Additionally, since carbon nanotubes are known to possess resilient mechanical properties and are chemically stable, the effect of periodic arrays of VACNTs on CAL-72 osteoblast-like cells was also studied. The periodicity and alignment of VACNTs considerably influenced growth, shape and orientation of the cells by steering toward the nanopattern. This situation is of great interest for the potential application of VACNTs in bone bioenginnering. This data provides evidence that CAL-72 osteoblast-like cells can sense physical features at the nanoscale. These results give a fascinating insight into the ways in which cell growth can be influenced by man-made nanostructures and could provide a framework for achieving controlled cell guidance with controlled organization and special physical properties.

Collagen-derived dipeptide prolyl-hydroxyproline promotes differentiation of MC3T3-E1 osteoblastic cells

International Nuclear Information System (INIS)

Kimira, Yoshifumi; Ogura, Kana; Taniuchi, Yuri; Kataoka, Aya; Inoue, Naoki; Sugihara, Fumihito; Nakatani, Sachie; Shimizu, Jun; Wada, Masahiro; Mano, Hiroshi

2014-01-01

Highlights: • Pro-Hyp did not affect MC3T3-E1 cell proliferation and matrix mineralization. • Pro-Hyp significantly increased alkaline phosphatase activity. • Pro-Hyp significantly upregulated gene expression of Runx2, Osterix, and Col1α1. - Abstract: Prolyl-hydroxyproline (Pro-Hyp) is one of the major constituents of collagen-derived dipeptides. The objective of this study was to investigate the effects of Pro-Hyp on the proliferation and differentiation of MC3T3-E1 osteoblastic cells. Addition of Pro-Hyp did not affect MC3T3-E1 cell proliferation and matrix mineralization but alkaline phosphatase activity was significantly increased. Furthermore, cells treated with Pro-Hyp significantly upregulated gene expression of Runx2, Osterix, and Col1α1. These results indicate that Pro-Hyp promotes osteoblast differentiation. This study demonstrates for the first time that Pro-Hyp has a positive effect on osteoblast differentiation with upregulation of Runx2, Osterix, and Collα1 gene expression

Genetic Manipulations of PPARs: Effects on Obesity and Metabolic Disease

Directory of Open Access Journals (Sweden)

Yaacov Barak

2007-01-01

Full Text Available The interest in genetic manipulations of PPARs is as old as their discovery as receptors of ligands with beneficial clinical activities. Considering the effects of PPAR ligands on critical aspects of systemic physiology, including obesity, lipid metabolism, insulin resistance, and diabetes, gene knockout (KO in mice is the ideal platform for both hypothesis testing and discovery of new PPAR functions in vivo. With the fervent pursuit of the magic bullet to eradicate the obesity epidemic, special emphasis has been placed on the impacts of PPARs on obesity and its associated diseases. As detailed in this review, understanding how PPARs regulate gene expression and basic metabolic pathways is a necessary intermediate en route to deciphering their effects on obesity. Over a decade and dozens of genetic modifications of PPARs into this effort, valuable lessons have been learned, but we are left with more questions to be answered. These lessons and future prospects are the subject of this review.

Lessons learned bulletin

International Nuclear Information System (INIS)

1994-05-01

During the past four years, the Department of Energy -- Savannah River Operations Office and the Westinghouse Savannah River Company (WSRC) Environmental Restoration (ER) Program completed various activities ranging from waste site investigations to closure and post closure projects. Critiques for lessons learned regarding project activities are performed at the completion of each project milestone, and this critique interval allows for frequent recognition of lessons learned. In addition to project related lessons learned, ER also performs lessons learned critiques. T'he Savannah River Site (SRS) also obtains lessons learned information from general industry, commercial nuclear industry, naval nuclear programs, and other DOE sites within the complex. Procedures are approved to administer the lessons learned program, and a database is available to catalog applicable lessons learned regarding environmental remediation, restoration, and administrative activities. ER will continue to use this database as a source of information available to SRS personnel

Resveratrol inhibits myeloma cell growth, prevents osteoclast formation, and promotes osteoblast differentiation

DEFF Research Database (Denmark)

Boissy, Patrice; Andersen, Thomas L; Abdallah, Basem M

2005-01-01

, a challenge for treating multiple myeloma is discovering drugs targeting not only myeloma cells but also osteoclasts and osteoblasts. Because resveratrol (trans-3,4',5-trihydroxystilbene) is reported to display antitumor activities on a variety of human cancer cells, we investigated the effects...... of this natural compound on myeloma and bone cells. We found that resveratrol reduces dose-dependently the growth of myeloma cell lines (RPMI 8226 and OPM-2) by a mechanism involving cell apoptosis. In cultures of human primary monocytes, resveratrol inhibits dose-dependently receptor activator of nuclear factor......RNA and cell surface protein levels and a decrease of NFATc1 stimulation and NF-kappaB nuclear translocation, whereas the gene expression of c-fms, CD14, and CD11a is up-regulated. Finally, resveratrol promotes dose-dependently the expression of osteoblast markers like osteocalcin and osteopontin in human bone...

Potential of Osteoblastic Cells Derived from Bone Marrow and Adipose Tissue Associated with a Polymer/Ceramic Composite to Repair Bone Tissue.

Science.gov (United States)

Freitas, Gileade P; Lopes, Helena B; Almeida, Adriana L G; Abuna, Rodrigo P F; Gimenes, Rossano; Souza, Lucas E B; Covas, Dimas T; Beloti, Marcio M; Rosa, Adalberto L

2017-09-01

One of the tissue engineering strategies to promote bone regeneration is the association of cells and biomaterials. In this context, the aim of this study was to evaluate if cell source, either from bone marrow or adipose tissue, affects bone repair induced by osteoblastic cells associated with a membrane of poly(vinylidene-trifluoroethylene)/barium titanate (PVDF-TrFE/BT). Mesenchymal stem cells (MSC) were isolated from rat bone marrow and adipose tissue and characterized by detection of several surface markers. Also, both cell populations were cultured under osteogenic conditions and it was observed that MSC from bone marrow were more osteogenic than MSC from adipose tissue. The bone repair was evaluated in rat calvarial defects implanted with PVDF-TrFE/BT membrane and locally injected with (1) osteoblastic cells differentiated from MSC from bone marrow, (2) osteoblastic cells differentiated from MSC from adipose tissue or (3) phosphate-buffered saline. Luciferase-expressing osteoblastic cells derived from bone marrow and adipose tissue were detected in bone defects after cell injection during 25 days without difference in luciferin signal between cells from both sources. Corroborating the in vitro findings, osteoblastic cells from bone marrow combined with the PVDF-TrFE/BT membrane increased the bone formation, whereas osteoblastic cells from adipose tissue did not enhance the bone repair induced by the membrane itself. Based on these findings, it is possible to conclude that, by combining a membrane with cells in this rat model, cell source matters and that bone marrow could be a more suitable source of cells for therapies to engineer bone.

Silver oxide-containing hydroxyapatite coating supports osteoblast function and enhances implant anchorage strength in rat femur.

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Eto, Shuichi; Miyamoto, Hiroshi; Shobuike, Takeo; Noda, Iwao; Akiyama, Takayuki; Tsukamoto, Masatsugu; Ueno, Masaya; Someya, Shinsuke; Kawano, Shunsuke; Sonohata, Motoki; Mawatari, Masaaki

2015-09-01

Antibacterial silver with hydroxyapatite (Ag-HA) is a promising coating material for imparting antibacterial properties to implants. We previously reported that 3% (w/w) silver with HA (3% Ag-HA) has both antibacterial activity and osteoconductivity. In this study, we investigated the effects of Ag-HA on the in vitro osteoblast function and the in vivo anchorage strength and osteoconductivity of implants. Production of the osteoblast marker alkaline phosphatase, but not cytotoxicity, was observed in cells of the osteoblast cell line MC3T3-E1 cultured on the 3% Ag-HA-coated surface. These results were similar to those observed with silver-free HA coating. In contrast, a significant high level of cytotoxicity was observed when the cells were cultured on a 50% Ag-HA-coated surface. The anchorage strength of implants inserted into the femur of Sprague-Dawley (SD) rats was enhanced by coating the implants with 3% Ag-HA. On the 3% Ag-HA-coated surface, both metaphyseal and diaphyseal areas were largely covered with new bone and had adequate osteoconductivity. These results suggest that 3% Ag-HA, like conventional HA, promotes osteogenesis by supporting osteoblast viability and function and thereby contributes to sufficient anchorage strength of implants. Application of 3% Ag-HA, which combines the osteoconductivity of HA and the antibacterial activity of silver, to prosthetic joints will help prevent postoperative infections. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats.

Science.gov (United States)

Hosokawa, Yoichiro; Sakakura, Yasunori; Irie, Kazuharu; Kudo, Kohsei; Kashiwakura, Ikuo

2010-01-01

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing.

Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats

International Nuclear Information System (INIS)

Hosokawa, Yoichiro; Kudo, Kohsei; Kashiwakura, Ikuo; Sakakura, Yasunori; Irie, Kazuharu

2010-01-01

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing. (author)

Caffeine Induces Cell Death via Activation of Apoptotic Signal and Inactivation of Survival Signal in Human Osteoblasts

Directory of Open Access Journals (Sweden)

Wen-Hsiung Chan

2008-05-01

Full Text Available Caffeine consumption is a risk factor for osteoporosis, but the precise regulatory mechanisms are currently unknown. Here, we show that cell viability decreases in osteoblasts treated with caffeine in a dose-dependent manner. This cell death is attributed primarily to apoptosis and to a smaller extent, necrosis. Moreover, caffeine directly stimulates intracellular oxidative stress. Our data support caffeine-induced apoptosis in osteoblasts via a mitochondria-dependent pathway. The apoptotic biochemical changes were effectively prevented upon pretreatment with ROS scavengers, indicating that ROS plays a critical role as an upstream controller in the caffeine-induced apoptotic cascade. Additionally, p21-activated protein kinase 2 (PAK2 and c-Jun N-terminal kinase (JNK were activated in caffeine-treated osteoblasts. Experiments further found that PAK2 activity is required for caffeine-induced JNK activation and apoptosis. Importantly, our data also show that caffeine triggers cell death via inactivation of the survival signal, including the ERK- and Akt-mediated anti-apoptotic pathways. Finally, exposure of rats to dietary water containing 10~20 μM caffeine led to bone mineral density loss. These results demonstrate for the first time that caffeine triggers apoptosis in osteoblasts via activation of mitochondria-dependent cell death signaling and inactivation of the survival signal, and causes bone mineral density loss in vivo.

[Low-frequency pulsed electromagnetic fields promotes rat osteoblast differentiation in vitro through cAMP/PKA signal pathway].

Science.gov (United States)

Fang, Qing-Qing; Li, Zhi-Zhong; Zhou, Jian; Shi, Wen-Gui; Yan, Juan-Li; Xie, Yan-Fang; Chen, Ke-Ming

2016-11-20

To study whether low-frequency pulsed electromagnetic fields promotes the differentiation of cultured rat osteoblasts through the cAMP/PKA signal pathway. Rat calvarial osteoblasts isolated by enzyme digestion were exposed to 50 Hz 0.6 mT low-frequency pulsed electromagnetic field for varying lengths of time, and the concentration of cAMP and levels of phosphorylated PKA in the cells were assayed. In cells treated with DDA to inhibit the activity of adenylate cyclase, the changes of ALP activity and transcription of osteogenic gene were detected after exposure to low-frequency pulsed electromagnetic field. The changes of osteogenic gene transcription and protein expression were tested in the osteoblasts pretreated with KT5720 in response to low-frequency pulsed electromagnetic field exposure. The intracellular cAMP concentration in the cells increased significantly at 20 min during exposure to low-frequency pulsed electromagnetic field, began to decrease at 40 min during the exposure, and increased again after a 2-h exposure; the same pattern of variation was also observed in p-PKA level. Application of DDA and KT5720 pretreatment both suppressed the increase in ALP activity and osteogenic gene transcription induced by electromagnetic field exposure. Low- frequency pulsed electromagnetic field exposure improves the differentiation of cultured rat osteoblasts by activating cAMP/PKA signal pathway.

Normal hematopoiesis and lack of β-catenin activation in osteoblasts of patients and mice harboring Lrp5 gain of function mutations

DEFF Research Database (Denmark)

Galan-Diez, Marta; Isa, Adiba; Ponzetti, Marco

2016-01-01

of hematopoiesis and leukemogenic properties of β-catenin activation in osteoblasts, that lead to development of acute myeloid leukemia (AML). Using mice with gain-of-function (GOF) Lrp5 alleles (Lrp5(A214V)) that recapitulate the human high bone mass (HBM) phenotype, as well as patients with the T253I HBM Lrp5...... mutation, we show here that Lrp5 GOF mutations in both humans and mice do not activate β-catenin signaling in osteoblasts. Consistent with a lack of β-catenin activation in their osteoblasts, Lrp5(A214V) mice have normal trilinear hematopoiesis. In contrast to leukemic mice with constitutive activation...... of β-catenin in osteoblasts (Ctnnb1(CAosb)), accumulation of early myeloid progenitors, a characteristic of AML, myeloid-blasts in blood, and segmented neutrophils or dysplastic megakaryocytes in the bone marrow, are not observed in Lrp5(A214V) mice. Likewise, peripheral blood count analysis in HBM...

Effect of thorium, cerium and lanthanium metals on the radiosensitivity of human osteoblasts

International Nuclear Information System (INIS)

Iwahara, Lucas Kiyoshi da Fonseca

2016-01-01

This work analyzed the effects of Th, Ce and La combinations on the human osteoblast proliferation. Due to the osteotropic potential of actinides and lanthanides, a human osteoblast cell line was used to evaluate the effects of metals on cell radiosensitivity using cell proliferation and total proteins as indicators. Assays were performed using cultures exposed to metal alone and in combination and to ionising radiation. It was not observed effects on proliferation for cultures exposed to the metals alone. Concerning the influence of the three elements on the radiosensitivity, it was seen that all three metals were able to interfere on this indicator, in a concentration dependent manner. Evaluating cultures exposed to binary mixtures (Th-Ce and Th-La) and a ternary mixture (Th-Ce-La), it was verified that there were chemical interactions between the metals, for the combinations tested. The results showed very strong antagonism on the inhibition of cell proliferation in cultures exposed to Th-La and Th- Ce-La combinations. Regarding the osteoblasts exposed to mixtures and to radiation it was seen an antagonistic effect on the cell proliferation in all tested combinations, and the Th-Ce combination with a higher degree. These results show that metal mixtures containing thorium, in association with ionising radiation, induced different effects on cell proliferation, regarding the exposure to the metals alone, suggesting the possibility that the combinations interfere on osteoblast radiosensitivity expressing the increase of the occupational hazard among workers involved with monazite sands. The results also indicate that the analysis of the effects of metal mixtures on human cells is a more realistic risk assessment in comparison with the analysis of risk for single elements. The work displays the need to development of risk assessment models that include the study of mixtures obtained in the work environment for the evaluation of cytotoxic and radiotoxic effects in

Overexpression of α-catenin increases osteoblastic differentiation in mouse mesenchymal C3H10T1/2 cells

International Nuclear Information System (INIS)

Kim, Dohee; Yang, Jae-Yeon; Shin, Chan Soo

2009-01-01

α- and β-Catenin link cadherins to the actin-based cytoskeleton at adherens junctions and regulate cell-cell adhesion. Although roles of cadherins and canonical Wnt-/β-catenin-signaling in osteoblastic differentiation have been extensively studied, the role of α-catenin is not known. Murine embryonic mesenchymal stem cells, C3H10T1/2 cells, were transduced with retrovirus encoding α-catenin (MSCV-α-catenin-HA-GFP). In the presence of Wnt-3A conditioned medium or osteogenic medium (β-glycerol phosphate and ascorbic acid), cells overexpressing α-catenin showed enhanced osteoblastic differentiation as measured by alkaline phosphatase (ALP) staining and ALP activity assay compared to cells transduced with empty virus (MSCV-GFP). In addition, mRNA expression of osteocalcin and Runx2 was significantly increased compared to control. Cell aggregation assay revealed that α-catenin overexpression has significantly increased cell-cell aggregation. However, cellular β-catenin levels (total, cytoplasmic-nuclear ratio) and β-catenin-TCF/LEF transcriptional activity did not change by overexpression of α-catenin. Knock-down of α-catenin using siRNA decreased osteoblastic differentiation as measured by ALP assay. These results suggest that α-catenin overexpression increases osteoblastic differentiation by increasing cell-cell adhesion rather than Wnt-/β-catenin-signaling.

The protective effect of platelet released growth factors and bone augmentation (Bio-Oss®) on ethanol impaired osteoblasts.

Science.gov (United States)

Sönmez, Tolga Taha; Bayer, Andreas; Cremer, Tillman; Hock, Jennifer Vanessa Phi; Lethaus, Bernd; Kweider, Nisreen; Wruck, Christoph Jan; Drescher, Wolf; Jahr, Holger; Lippross, Sebastian; Pufe, Thomas; Tohidnezhad, Mersedeh

2017-11-01

Chronic alcohol consumption is a known limiting factor for bone healing. One promising strategy to improve bone augmentation techniques with Bio-Oss ® in oral and maxillofacial surgery might be the supportive application of platelet-concentrated biomaterials as platelet-released growth factor (PRGF). To address this matter, we performed an in vitro study investigating the protective effects of PRGF and Bio-Oss ® in ethanol (EtOH) treated osteoblasts. The SAOS-2 osteosarcoma cell line, with and without EtOH pretreatment was used. The cell viability, proliferation and alkali phosphatase activity (ALP) after application of 0%, 5% and 10% PRGF and Bio-Oss ® were assessed. The application of PRGF and Bio-Oss ® in EtOH impaired osteoblasts showed a significant beneficial influence increasing the viability of the osteoblasts in cell culture. The synergistic effect of Bio-Oss ® and 5% PRGF on the proliferation of osteoblasts was also demonstrated. Bio-Oss ® only in combination with PRGF increases the alkaline phosphatase (ALP) activity in EtOH pretreated cells. These results indicate that the simultaneous application of PRGF and Bio-Oss ® inhibits EtOH induced bone healing impairment. Furthermore, in the cells, PRGF induced a protective mechanism which might promote bone regeneration. Copyright © 2017 Elsevier GmbH. All rights reserved.

In vitro evaluation of osteoblastic cells on bacterial cellulose modified with multi-walled carbon nanotubes as scaffold for bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Gutiérrez-Hernández, José Manuel [Coordination for Innovation and Application of Science and Technology, Autonomous University San Luis Potosi, 78000 San Luis Potosi (Mexico); Department of Wood, Cellulose and Paper Research, University Guadalajara, 45110 Guadalajara (Mexico); Escobar-García, Diana María [Laboratory of Basic Sciences, Faculty of Dentistry, Autonomous University San Luis Potosi, 78000 San Luis Potosi (Mexico); Escalante, Alfredo [Department of Wood, Cellulose and Paper Research, University Guadalajara, 45110 Guadalajara (Mexico); Flores, Hector [Laboratory of Basic Sciences, Faculty of Dentistry, Autonomous University San Luis Potosi, 78000 San Luis Potosi (Mexico); González, Francisco Javier [Coordination for Innovation and Application of Science and Technology, Autonomous University San Luis Potosi, 78000 San Luis Potosi (Mexico); Gatenholm, Paul [Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Biopolymer Technology, SE-412 96 Göteborg (Sweden); Toriz, Guillermo, E-mail: gtoriz@dmcyp.cucei.udg.mx [Department of Wood, Cellulose and Paper Research, University Guadalajara, 45110 Guadalajara (Mexico); Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Biopolymer Technology, SE-412 96 Göteborg (Sweden)

2017-06-01

In this paper we explore the use of native bacterial cellulose (BC) in combination with functionalized multi-walled carbon nanotubes (MWNTs) as an original biomaterial, suitable three-dimensional (3D) scaffold for osteoblastic cell culture. Functionalized MWNTs were mixed with native BC (secreted by Gluconacetobacter xylinus) with the aim of reinforcing the mechanical properties of BC. The results indicate that BC-MWNTs scaffolds support osteoblast viability, adhesion and proliferation at higher levels as compared to traditional culture substrates. Chemically functionalized MWNTs are also an excellent material to be used as scaffold because these did not affect cell viability and showed an enhanced osteoblast adhesion. These results suggest the potential for this combination of biomaterials, i.e. BC and carbon nanomaterials, as scaffolds for bone regeneration. - Highlights: • Functionalization of multiwalled carbon nanotubes with carboxyl groups for reduces their toxicity against osteoblastic cells. • Use of native bacterial cellulose with functionalized multi-walled carbon nanotubes as scaffolds for tissue engineering. • Bacterial cellulose with multi-walled carbon nanotubes as scaffolds give an excellent option to be used in bone regeneration.

In vitro evaluation of osteoblastic cells on bacterial cellulose modified with multi-walled carbon nanotubes as scaffold for bone regeneration

International Nuclear Information System (INIS)

Gutiérrez-Hernández, José Manuel; Escobar-García, Diana María; Escalante, Alfredo; Flores, Hector; González, Francisco Javier; Gatenholm, Paul; Toriz, Guillermo

2017-01-01

In this paper we explore the use of native bacterial cellulose (BC) in combination with functionalized multi-walled carbon nanotubes (MWNTs) as an original biomaterial, suitable three-dimensional (3D) scaffold for osteoblastic cell culture. Functionalized MWNTs were mixed with native BC (secreted by Gluconacetobacter xylinus) with the aim of reinforcing the mechanical properties of BC. The results indicate that BC-MWNTs scaffolds support osteoblast viability, adhesion and proliferation at higher levels as compared to traditional culture substrates. Chemically functionalized MWNTs are also an excellent material to be used as scaffold because these did not affect cell viability and showed an enhanced osteoblast adhesion. These results suggest the potential for this combination of biomaterials, i.e. BC and carbon nanomaterials, as scaffolds for bone regeneration. - Highlights: • Functionalization of multiwalled carbon nanotubes with carboxyl groups for reduces their toxicity against osteoblastic cells. • Use of native bacterial cellulose with functionalized multi-walled carbon nanotubes as scaffolds for tissue engineering. • Bacterial cellulose with multi-walled carbon nanotubes as scaffolds give an excellent option to be used in bone regeneration.

Boron nitride nanotube reinforced polylactide-polycaprolactone copolymer composite: mechanical properties and cytocompatibility with osteoblasts and macrophages in vitro.

Science.gov (United States)

Lahiri, Debrupa; Rouzaud, Francois; Richard, Tanisha; Keshri, Anup K; Bakshi, Srinivasa R; Kos, Lidia; Agarwal, Arvind

2010-09-01

Biodegradable polylactide-polycaprolactone copolymer (PLC) has been reinforced with 0, 2 and 5wt.% boron nitride nanotubes (BNNTs) for orthopedic scaffold application. Elastic modulus of the PLC-5wt.% BNNT composite, evaluated through nanoindentation technique, shows a 1370% increase. The same amount of BNNT addition to PLC enhances the tensile strength by 109%, without any adverse effect on the ductility up to 240% elongation. Interactions of the osteoblasts and macrophages with bare BNNTs prove them to be non-cytotoxic. PLC-BNNT composites displayed increased osteoblast cell viability as compared to the PLC matrix. The addition of BNNTs also resulted in an increase in the expression levels of the Runx2 gene, the main regulator of osteoblast differentiation. These results indicate that BNNT is a potential reinforcement for composites for orthopedic applications. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Polycythemia is associated with bone loss and reduced osteoblast activity in mice

NARCIS (Netherlands)

Oikonomidou, P R; Casu, C; Yang, Z; Crielaard, B; Shim, J H; Rivella, S; Vogiatzi, M G

2015-01-01

Increased fragility has been described in humans with polycythemia vera (PV). Herein, we describe an osteoporotic phenotype associated with decreased osteoblast activity in a mouse model of PV and another mouse of polycythemia and elevated circulating erythropoietin (EPO). Our results are important

A specific subtype of osteoclasts secretes factors inducing nodule formation by osteoblasts

DEFF Research Database (Denmark)

Henriksen, Kim; Andreassen, Kim V; Thudium, Christian S

2012-01-01

Osteoclasts are known to be important for the coupling process between bone resorption and formation. The aim of this study was to address when osteoclasts are anabolically active. Human monocytes were differentiated into mature osteoclasts by treatment with M-CSF and RANKL. Conditioned medium wa...... dependent and independent of their resorptive activity, secrete factors stimulating osteoblastic bone formation.......Osteoclasts are known to be important for the coupling process between bone resorption and formation. The aim of this study was to address when osteoclasts are anabolically active. Human monocytes were differentiated into mature osteoclasts by treatment with M-CSF and RANKL. Conditioned medium...... release. The osteoblastic cell line 2T3 was treated with 50% of CM or non-CM for 12days. Bone formation was assessed by Alizarin Red extraction. CM from mature osteoclasts induced bone formation, while CM from macrophages did not. Non-resorbing osteoclasts generated from osteopetrosis patients showed...

Sr-substituted bone cements direct mesenchymal stem cells, osteoblasts and osteoclasts fate.

Directory of Open Access Journals (Sweden)

Monica Montesi

Full Text Available Strontium-substituted apatitic bone cements enriched with sodium alginate were developed as a potential modulator of bone cells fate. The biological impact of the bone cement were investigated in vitro through the study of the effect of the nanostructured apatitic composition and the doping of strontium on mesenchymal stem cells, pre-osteoblasts and osteoclasts behaviours. Up to 14 days of culture the bone cells viability, proliferation, morphology and gene expression profiles were evaluated. The results showed that different concentrations of strontium were able to evoke a cell-specific response, in fact an inductive effect on mesenchymal stem cells differentiation and pre-osteoblasts proliferation and an inhibitory effect on osteoclasts activity were observed. Moreover, the apatitic structure of the cements provided a biomimetic environment suitable for bone cells growth. Therefore, the combination of biological features of this bone cement makes it as promising biomaterials for tissue regeneration.

Breathing Life into Engineering: A Lesson Study Life Science Lesson

Science.gov (United States)

Lawrence, Maria; Yang, Li-Ling; Briggs, May; Hession, Alicia; Koussa, Anita; Wagoner, Lisa

2016-01-01

A fifth grade life science lesson was implemented through a lesson study approach in two fifth grade classrooms. The research lesson was designed by a team of four elementary school teachers with the goal of emphasizing engineering practices consistent with the "Next Generation Science Standards" (NGSS) (Achieve Inc. 2013). The fifth…

[Effect of lipopolysaccharides extracted from Porphyromonas endodontalis on the expression of CD14 in osteoblast].

Science.gov (United States)

Jia, Ge; Qiu, Li-hong; Li, Ren; Yang, Di; Guo, Yan

2010-10-01

To investigate the effect of lipopolysaccharides(LPS) extracted from Porphyromonas endodontalis(P.e) on the expression of CD14 in osteoblast. Under the condition with or without serum, MC3T3-E1 cells were stimulated with 10 μg/mL P.e-LPS for 24 hours, then the expression of CD14 was measured using flow cytometry; the membrane CD14 mRNA was detected at different time point (0, 1, 3, 6, 12, 24 h) by RT-PCR. Statistical analysis was performed using two-sample t test, one-way ANOVA and Dunnett t test with SPSS13.0 software package. Flow cytometry showed that CD14 protein increased after the stimulation of P.e-LPS for 24 h, while the non-serum group demonstrated more increase; the membrane CD14 mRNA level was up-regulated by 10 μg/mL P.e-LPS at 1 hour, and reached the maximum at 3 h and declined after 6 h. P.e-LPS can induce the expression of CD14 in osteoblast MC3T3-E1, which indicates that P.e-LPS may play an important role in osteoblast through CD14.

Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

Energy Technology Data Exchange (ETDEWEB)

Nirmala, R. [Bio-nano System Engineering, College of Engineering, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of); Park, Hye-Min [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Navamathavan, R. [School of Advanced Materials Engineering, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); Kang, Hyung-Sub [Department of Pharmacology and Toxicology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561 756 (Korea, Republic of); El-Newehy, Mohamed H. [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Kim, Hak Yong, E-mail: khy@jbnu.ac.kr [Petrochemical Research Chair, Department of Chemistry, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Center for Healthcare Technology and Development, Chonbuk National University, Jeonju, 561 756 (Korea, Republic of)

2011-03-12

In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

Lecithin blended polyamide-6 high aspect ratio nanofiber scaffolds via electrospinning for human osteoblast cell culture

International Nuclear Information System (INIS)

Nirmala, R.; Park, Hye-Min; Navamathavan, R.; Kang, Hyung-Sub; El-Newehy, Mohamed H.; Kim, Hak Yong

2011-01-01

In this study, we focused on the preparation and characterization of lecithin blended polyamide-6 nanofibers via an electrospinning process for human osteoblastic (HOB) cell culture applications. The morphological, structural characterizations and thermal properties of polyamide-6/lecithin nanofibers were determined by using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA). SEM images revealed that the nanofibers were well-oriented with good incorporation of lecithin. FT-IR results indicated the presence of amino groups of lecithin in the blended nanofibers. TGA analysis revealed that the onset degradation temperature decreased with increasing lecithin content in the blended nanofibers. The morphological features of cells attached on polyamide-6/lecithin nanofibers were confirmed by SEM. The adhesion, viability and proliferation properties of osteoblast cells on the polyamide-6/lecithin blended nanofibers were analyzed by in vitro cell compatibility test. This study demonstrated the non-cytotoxic behavior of electrospun polyamide-6/lecithin nanofibers for the osteoblast cell culture.

Biocompatibility of the titanium-based implant surfaces: Effect of the calcium dihydrogen phosphate on osteoblast cells

Directory of Open Access Journals (Sweden)

Kaluđerović Milena R.

2016-01-01

Full Text Available The influence of the presence of calcium dihydrogen phosphate in acid media on titanium-based implant surfaces, Ticer, employed in clinics, and its white form (Ticer white, on osteoblast cells was investigated. Novel surfaces M1 and M2 were obtained by immersing Ticer and Ticer white surfaces in calcium dihydrogen phosphate solution at pH 3.5. The surfaces were characterized by SEM, EDS and X-ray diffraction. The results related to interaction of investigated surfaces and human osteoblast cells from indirect biocompatibility (MTT and SRB assays, proliferation (DAPI assay and mode of cell death (acridine orange/ethidium bromide (AO/EB double staining were found to be in good agreement, as well as findings from osteocalcin (OC and bone sialoprotein (BSP expression. Surfaces were obtained by employing anodic plasma-electrochemical oxidation with spark discharges without subsequent surface modifications were found to be more compatible. Soaking of Ticer and Ticer white in phosphate solution gave toxic materials (M1 and M2 which induced apoptosis and secondary necrosis in osteoblast cells.

Osteoblast Adhesion on Cathodic Arc Plasma Deposited Nano-Multilayered TiCrAlSiN Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun Kyu [University of Ulsan, Ulsan (Korea, Republic of); Pham, Vuong Hung [Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam)

2014-03-15

Adhesion of osteoblast cells to TiCrAlSiN thin films was evaluated in vitro. Ti and TiCrAlSiN thin films were deposited on glass substrates by cathodic arc deposition. Surface roughness and chemistry of the TiCrAlSiN thin films was characterized by AFM and EPMA, respectively. Ti and TiCrAlSiN thin films and glass coverslips were cultured with human osteoblast cells (hFOB 1.19). The cell cytoskeleton was analyzed by observing the organization of actin stress fibers and microtubules. Cell proliferation was investigated by MTT assay and visualization. Focal contact adhesion was studied by observing the vinculin density. The results indicated that the TiCrAlSiN coating significantly influenced the actin cytoskeleton and microtubule organization. Human osteoblasts hFOB attached and proliferated better on TiCrAlSiN thin films with more focal contact adhesions than on Ti thin films or glass surfaces. These results suggest that TiCrAlSiN thin films can be an implantable material where the maximum cell adhesion is required.

Similar healthy osteoclast and osteoblast activity on nanocrystalline hydroxyapatite and nanoparticles of tri-calcium phosphate compared to natural bone

Directory of Open Access Journals (Sweden)

MacMillan AK

2014-12-01

Full Text Available Adam K MacMillan,1 Francis V Lamberti,1 Julia N Moulton,2 Benjamin M Geilich,2 Thomas J Webster2,3 1RTI Surgical, Alachua, FL, USA; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 3Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: While there have been numerous studies to determine osteoblast (bone forming cell functions on nanocrystalline compared to micron crystalline ceramics, there have been few studies which have examined osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and receptor activator of nuclear factor κB [RANK]. This is despite the fact that osteoclasts are an important part of maintaining healthy bone since they resorb bone during the bone remodeling process. Moreover, while it is now well documented that bone formation is enhanced on nanoceramics compared to micron ceramics, some have pondered whether osteoblast functions (such as osteoprotegerin and RANK ligand [RANKL] are normal (ie, non-diseased on such materials compared to natural bone. For these reasons, the objective of the present in vitro study was to determine various functions of osteoclasts and osteoblasts on nanocrystalline and micron crystalline hydroxyapatite as well as tri-calcium phosphate materials and compare such results to cortical and cancellous bone. Results showed for the first time similar osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and RANK and osteoblast activity (osteoprotegerin and RANKL on nanocrystalline hydroxyapatite compared to natural bone, whereas osteoclast and osteoblast functions on micron crystalline versions of these ceramics were much different than natural bone. In this manner, this study provides additional evidence that nanocrystalline calcium phosphates can serve as suitable synthetic

Alteration in Bone Mineral Metabolism in Children with Acute Lymphoblastic Leukemia (ALL: A Review

Directory of Open Access Journals (Sweden)

Chowdhury Yakub Jamal

2009-11-01

Full Text Available In recent years there has been a significant increase in event free survival (EFS and overall survival in children with cancer. As survival rates for childhood cancer have radically improved, late effects associated with the successful but highly intensive chemotherapy and/or radiotherapy have dramatically increased. Many possible late effects of cancer treatment are recognized in pediatric cancer patients as infertility, endocrine deficiency, renal failure, pulmonary and cardiac toxicity, obesity and osteopenia/osteoporosis. Decreased bone mineral density (BMD and bone metabolism disturbances have been recognized and reported in literature. Osteopenia/osteoporosis skeletal abnormalities, osteonecrosis and pathological fractures are known to occur frequently in childhood acute lymphoblastic leukemia (ALL at diagnosis, during and after treatment with chemotherapy. Various studies have revealed different metabolic alterations related to ALL. Some suggestions have been made about their relationship with the disease process. Various metabolic abnormalities may be encountered in the newly diagnosed ALL patients. It includes decreased and increased serum levels of calcium and phosphate. Hypercalcemia may result from leukemic infiltrations of bone and release of parathormone like substance from lymphoblast. Elevated serum phosphate can occur as a result of leukemic cell lysis and may induce hypocalcemia. It has been postulated by other authors that leukemic cells may directly infiltrate bone and produce parathroid hormone related peptides, prostaglandin E and osteoblast inhibiting factors. Hypomagnesemia, hypocalcaemia and hypothyroidisum have been demonstrated in patients with ALL. Some patients may have poor nutrition and decreased physical activities during treatment. However postulations have also been made that chemotherapy may play a role in creating metabolic alterations in children with ALL. Corticosteroid, methotraxate and cranial irradiations

Effect of Irradiation on Apoptosis, Cell Cycle Arrest and Calcified Nodule Formation of Rat Calvarial Osteoblast

International Nuclear Information System (INIS)

Lee, Young Mi; Choi, Hang Moon; Heo, Min Suk; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won

2000-01-01

The study was aimed to detect the induction of apoptosis, cell cycle arrest and calcified nodule formation after irradiation on primarily cultured osteoblasts. Using rat calvarial osteoblasts, the effects of irradiation on apoptosis, cell cycle arrest, and calcified nodule formation were studied. The single irradiation of 10, 20 Gy was done with 5.38 Gy/min dose rate using the 137 Cs cell irradiator at 4th and 14th day of culture. Apoptosis induction and cell cycle arrest were assayed by the flow cytometry at 1, 2, 3, and 4 days after irradiation. The formation of calcified nodules was observed by alizarin red staining at 1, 3, 10, 14 days after irradiation at 4th day of culture, and at 1, 4, 5 days after irradiation at 14th day of culture. Apoptosis was not induced by 10 or 20 Gy independent of irradiation and culture period. Irradiation did not induced G1 arrest in post-irradiated osteoblasts. After irradiation at 4th-day of culture, G2 arrest was induced but it was not statistically significant after irradiation at 14th-day of culture. In the case of irradiated cells at 4th day of culture, calcified nodules were not formed and at 14th-day of culture after irradiation, calcified nodule formation did not affected. Taken together, these results suggest that irradiation at the dose of 10-20 Gy would not affect apoptosis induction of osteoblasts. Cell cycle and calcified nodule formation were influenced by the level of differentiation of osteblasts.

Platelet-poor plasma stimulates the proliferation but inhibits the differentiation of rat osteoblastic cells in vitro.

Science.gov (United States)

Hamdan, Ahmad Abdel-Salam; Loty, Sabine; Isaac, Juliane; Bouchard, Philippe; Berdal, Ariane; Sautier, Jean-Michel

2009-06-01

Recent studies have shown that the use of platelet preparations in bone and implant surgery might stimulate bone formation. However, the biological mechanisms are not well understood. Moreover, few studies have attempted to evaluate the effect of platelet-poor plasma (PPP), which is a product of the platelet-rich plasma preparation process. Thus, this study investigated the behavior of osteoblasts isolated from fetal rat calvaria cultivated in the presence of homologous PPP. PPP was obtained by centrifugation of the rat mother's blood and used in replacement of fetal calf serum, which is classically used in primary culture procedures. Proliferation was measured by an MTT assay at 24, 48, and 72 h. Real-time PCR was performed to study the expression of Runx2, Dlx5, and osteocalcin (OC) on days 0 (4 h), 1, 3, 7, and 12. Alkaline phosphatase (ALP) biochemical activity was evaluated on days 0 (4 h), 1, 3, 7, and 12. Observations by phase-contrast microscopy showed that osteoblasts were able to differentiate until the mineralization of the matrix in the presence of PPP. PPP enhanced the proliferation significantly compared with the control group (Pexpressed by cells in the experimental group at lower levels compared with the control group. Biochemical assay of ALP showed a lower activity in the experimental group compared with the control group (P<0.001). These results suggest that, in the presence of homologous PPP, rat osteoblastic cells are able to maintain their phenotype, with a higher rate of proliferation. However, PPP seems to inhibit osteoblastic differentiation.

Effect of human vascular endothelial growth factor gene transfer on endogenous vascular endothelial growth factor mRNA expression in a rat fibroblast and osteoblast culture model.

Science.gov (United States)

Li, Ru; Li, Claire H; Nauth, Aaron; McKee, Michael D; Schemitsch, Emil H

2010-09-01

Vascular endothelial growth factor (VEGF) plays an important role in promoting angiogenesis and osteogenesis during fracture repair. Our previous studies have shown that cell-based VEGF gene therapy enhances bone healing of a rabbit tibia segmental bone defect in vivo. The aim of this project was to examine the effect of exogenous human VEGF on the endogenous rat VEGF messenger RNA (mRNA) expression in a cell-based gene transfer model. Rat fibroblasts and osteoblasts were harvested from the dermal tissue and periosteum, respectively, of Fisher 344 rats. The cells were then cultured and transfected with pcDNA-human VEGF using Superfect reagent (Qiagen). Four experimental groups were created: 1) fibroblast-VEGF; 2) osteoblast-VEGF; 3) nontransfected fibroblast controls; and 4) nontransfected osteoblast controls. The cultured cells were harvested at 1, 3, and 7 days after the gene transfection. The total mRNA was extracted (Trizol; Invitrogen); both human VEGF and rat VEGF mRNA were measured by reverse transcriptase-polymerase chain reaction and quantified by VisionWorksLS. The human VEGF165 mRNA was detected by reverse transcriptase-polymerase chain reaction from transfected fibroblasts and osteoblasts at 1, 3, and 7 days after gene transfection. The human VEGF165 levels peaked at Day 1 and then gradually reduced expression in both transfected fibroblasts and osteoblasts. Two endogenous rat VEGF isoforms were detected in this cell culture model: rat VEGF120 and rat VEGF164. We compared the rat VEGF120 and rat VEGF164 expression level of the fibroblasts or osteoblasts that were transfected with human VEGF165, with nontransfected control cells. Both the transfected fibroblasts and osteoblasts showed greater expression of rat VEGF164 than nontransfected controls at Day 1 (peak level) and Day 3, but not at Day 7. The expression of rat VEGF120 was lower in transfected fibroblasts, but higher in transfected osteoblasts, than the relevant control groups at any time point

Effects of Apatite Cement Containing Atelocollagen on Attachment to and Proliferation and Differentiation of MC3T3-E1 Osteoblastic Cells

Directory of Open Access Journals (Sweden)

Masaaki Takechi

2016-04-01

Full Text Available To improve the osteoconductivity of apatite cement (AC for reconstruction of bone defects after oral maxillofacial surgery, we previously fabricated AC containing atelocollagen (AC(ate. In the present study, we examined the initial attachment, proliferation and differentiation of mouse osteoblastic cells (MC3T3-E1 cells on the surface of conventional AC (c-AC, AC(ate and a plastic cell dish. The number of osteoblastic cells showing initial attachment to AC(ate was greater than those attached to c-AC and similar to the number attached to the plastic cell wells. We also found that osteoblastic cells were well spread and increased their number on AC(ate in comparison with c-AC and the wells without specimens, while the amount of procollagen type I carboxy-terminal peptide (PIPC produced in osteoblastic cells after three days on AC(ate was greater as compared to the others. There was no significant difference in regard to alkaline phosphatase (ALP activity and osteocalcin production by osteoblastic cells among the three surface types after three and six days. However, after 12 days, ALP activity and the produced osteocalcin were greater with AC(ate. In conclusion, AC(ate may be a useful material with high osteoconductivity for reconstruction of bone defects after oral maxillofacial surgery.

Pulsed Electromagnetic Field Regulates MicroRNA 21 Expression to Activate TGF-β Signaling in Human Bone Marrow Stromal Cells to Enhance Osteoblast Differentiation

Directory of Open Access Journals (Sweden)

Nagarajan Selvamurugan

2017-01-01

Full Text Available Pulsed electromagnetic fields (PEMFs have been documented to promote bone fracture healing in nonunions and increase lumbar spinal fusion rates. However, the molecular mechanisms by which PEMF stimulates differentiation of human bone marrow stromal cells (hBMSCs into osteoblasts are not well understood. In this study the PEMF effects on hBMSCs were studied by microarray analysis. PEMF stimulation of hBMSCs’ cell numbers mainly affected genes of cell cycle regulation, cell structure, and growth receptors or kinase pathways. In the differentiation and mineralization stages, PEMF regulated preosteoblast gene expression and notably, the transforming growth factor-beta (TGF-β signaling pathway and microRNA 21 (miR21 were most highly regulated. PEMF stimulated activation of Smad2 and miR21-5p expression in differentiated osteoblasts, and TGF-β signaling was essential for PEMF stimulation of alkaline phosphatase mRNA expression. Smad7, an antagonist of the TGF-β signaling pathway, was found to be miR21-5p’s putative target gene and PEMF caused a decrease in Smad7 expression. Expression of Runx2 was increased by PEMF treatment and the miR21-5p inhibitor prevented the PEMF stimulation of Runx2 expression in differentiating cells. Thus, PEMF could mediate its effects on bone metabolism by activation of the TGF-β signaling pathway and stimulation of expression of miR21-5p in hBMSCs.

The Knitting Lesson.

Science.gov (United States)

Smith, Pamela

1987-01-01

Based on Jean-Francois Millet's 1869 painting, "The Knitting Lesson," this lesson's goal is to introduce students in grades seven through nine to genre (everyday life) painting the nineteenth century. The lesson is also designed to show that some aspects of genre may be timeless. (BSR)

Intrinsically superparamagnetic Fe-hydroxyapatite nanoparticles positively influence osteoblast-like cell behaviour

Science.gov (United States)

2012-01-01

Background Superparamagnetic nanoparticles (MNPs) have been progressively explored for their potential in biomedical applications and in particular as a contrast agent for diagnostic imaging, for magnetic drug delivery and more recently for tissue engineering applications. Considering the importance of having safe MNPs for such applications, and the essential role of iron in bone remodelling, this study developed and analysed novel biocompatible and bioreabsorbable superparamagnetic nanoparticles, that avoid the use of poorly tolerated magnetite based nanoparticles, for bone tissue engineering applications. Results MNPs were obtained by doping hydroxyapatite (HA) with Fe ions, by directly substituting Fe2+ and Fe3+ into the HA structure yielding superparamagnetic bioactive phase. In the current study, we have investigated the effects of increasing concentrations (2000 μg/ml; 1000 μg/ml; 500 μg/ml; 200 μg/ml) of FeHA MNPs in vitro using Saos-2 human osteoblast-like cells cultured for 1, 3 and 7 days with and without the exposure to a static magnetic field of 320 mT. Results demonstrated not only a comparable osteoblast viability and morphology, but increased in cell proliferation, when compared to a commercially available Ha nanoparticles, even with the highest dose used. Furthermore, FeHA MNPs exposure to the static magnetic field resulted in a significant increase in cell proliferation throughout the experimental period, and higher osteoblast activity. In vivo preliminary results demonstrated good biocompatibility of FeHA superparamagnetic material four weeks after implantation into a critical size lesion of the rabbit condyle. Conclusions The results of the current study suggest that these novel FeHA MNPs may be particularly relevant for strategies of bone tissue regeneration and open new perspectives for the application of a static magnetic field in a clinical setting of bone replacement, either for diagnostic imaging or magnetic drug delivery

Microscopic observations of osteoblast growth on micro-arc oxidized β titanium

Science.gov (United States)

Chen, Hsien-Te; Chung, Chi-Jen; Yang, Tsai-Ching; Tang, Chin-Hsin; He, Ju-Liang

2013-02-01

Titanium alloys are widely used in orthopedic and dental implants, owing to their excellent physical properties and biocompatibility. By using the micro-arc oxidation (MAO), we generated anatase-rich (A-TiO2) and rutile-rich (R-TiO2) titanium dioxide coatings, individually on β-Ti alloy, in which the latter achieved an enhanced in vitro and in vivo performance. Thoroughly elucidating how the osteoblasts interact with TiO2 coatings is of worthwhile interest. This study adopts the focused ion beam (FIB) to section off the TiO2 coated samples for further scanning electron microscope (SEM) and transmission electron microscope (TEM) observation. The detailed crystal structures of the TiO2 coated specimens are also characterized. Experimental results indicate osteoblasts adhered more tenaciously and grew conformably with more lamellipodia extent on the R-TiO2 specimen than on the A-TiO2 and raw β-Ti specimens. FIB/SEM cross-sectional images of the cell/TiO2 interface revealed micro gaps between the cell membrane and contact surface of A-TiO2 specimen, while it was not found on the R-TiO2 specimen. Additionally, the number of adhered and proliferated cells on the R-TiO2 specimen was visually greater than the others. Closely examining EDS line scans and elemental mappings of the FIB/TEM cross-sectional images of the cell/TiO2 interface reveals both the cell body and interior space of the TiO2 coating contain nitrogen and sulfur (the biological elements in cell). This finding supports the assumption that osteoblast can grow into the porous structure of TiO2 coatings and demonstrating that the R-TiO2 coating formed by MAO serves the best for β-Ti alloys as orthopedic and dental implants.

Zirconia coated titanium for implants and their interactions with osteoblast cells

International Nuclear Information System (INIS)

Kaluđerović, Milena R.; Schreckenbach, Joachim P.; Graf, Hans-Ludwig

2014-01-01

The anodic plasma-electrochemical oxidation in aqueous electrolytes of Zr(SO 4 ) 2 was used to prepare new zirconia/titania-based surfaces M1 (Ti, Zr and O: 7–10, 22–27 and 65–69 at.%) and M2 (Ti, Zr and O: 11–13, 20–23 and 64–69 at.%). The chemical composition and the microstructure of these coatings were characterized by surface and solid state techniques such as scanning electron microscopy, electron probe microanalysis, Raman spectroscopy and X-ray diffraction. These mixed oxides of ZrO 2 /TiO 2 surfaces consist up to 84% (m/m) of ZrO 2 and 16% (m/m) of TiO 2 . Monoclinic zirconia was detected as the dominant microcrystalline phase. In vitro studies were conducted on primary human osteoblast cells. MTT and DAPI assays were used for assessment on cell proliferation. Immunohistochemical analyses of morphology, cell cluster formation and expression of bone sialoprotein (BSP) and osteocalcin (OC) were performed. Novel surfaces M1 and M2 induced proliferation and expression of OC and BSP similarly to Ticer, used in clinical practice. Furthermore, the presence of zirconia on titanium surface has a higher beneficial effect on the osteoblast morphological changes and cell cluster formation. - Highlights: • Surfaces M1 and M2 (up to 84% (m/m) ZrO 2 and 16% (m/m) TiO 2 ) were prepared. • Novel materials promote proliferation of human osteoblasts similarly to Ticer. • Morphological changes and cell cluster formation are induced faster on M1 and M2. • Higher expression of OC and BSP is caused by M1 and M2. • M1 and M2 may influence the rate of bone formation

Demonstration of the presence of independent pre-osteoblastic and pre-adipocytic cell populations in bone marrow-derived mesenchymal stem cells

DEFF Research Database (Denmark)

Post, S; Abdallah, B M; Bentzon, J F

2008-01-01

differentiation into one particular lineage. However, this inverse relationship between bone and fat is not consistent and under certain in vivo conditions, bone and fat can change independently suggesting separate precursor cell populations. In order to test for this hypothesis, we extensively characterized two...... of mature adipocytes visualized by Oil Red O staining. On the other hand, mMSC2 and not mMSC1 differentiated to osteoblast lineage as demonstrated by up-regulation of osteoblastic makers (CBFA1/RUNX2, Osterix, alkaline phosphatase, bone sialoprotein and osteopontin) and formation of alizarin red stained...... that are committed to either osteoblast or adipocyte lineage. These cell populations may undergo independent changes during aging and in bone diseases and thus represent important targets for therapy....

Calcite as a bone substitute. Comparison with hydroxyapatite and tricalcium phosphate with regard to the osteoblastic activity

Energy Technology Data Exchange (ETDEWEB)

Monchau, F., E-mail: Francine.monchau@univ-artois.fr [Laboratoire Genie Civil et geo-Environnement (EA 4515, Universite Lille Nord de France), Equipe Biomateriaux Artois (Universite d' Artois), IUT/GMP, 1230, rue de l' Universite, BP 819, 62408 Bethune cedex (France); Hivart, Ph.; Genestie, B. [Laboratoire Genie Civil et geo-Environnement (EA 4515, Universite Lille Nord de France), Equipe Biomateriaux Artois (Universite d' Artois), IUT/GMP, 1230, rue de l' Universite, BP 819, 62408 Bethune cedex (France); Chai, F. [Laboratoire Medicaments et Biomateriaux a Liberation Controlee (INSERM U 1008, Universite Lille Nord de France), Groupe de Recherche sur les Biomateriaux (Universite Lille-2), Faculte de Medecine, 1, place de Verdun, 59045 Lille cedex (France); and others

2013-01-01

Close to the bone mineral phase, the calcic bioceramics, such as hydroxyapatite (HA) and {beta}-tricalcium phosphate ({beta}-TCP), are commonly used as substitutes or filling materials in bone surgery. Besides, calcium carbonate (CaCO{sub 3}) is also used for their excellent biocompatibility and bioactivity. However, the problem with the animal-origin aragonite demands the new technique to synthesize pure calcite capable of forming 3D bone implant. This study aims to manufacture and evaluate a highly-pure synthetic crystalline calcite with good cytocompatibility regarding to the osteoblasts, comparing to that of HA and {beta}-TCP. After the manufacture of macroporous bioceramic scaffolds with the identical internal architecture, their cytocompatibility is studied through MC3T3-E1 osteoblasts with the tests of cell viability, proliferation, vitality, etc. The results confirmed that the studied process is able to form a macroporous material with a controlled internal architecture, and this synthesized calcite is non-cytotoxic and facilitate the cell proliferation. Indeed requiring further improvement, the studied calcite is definitely an interesting alternative not only to coralline aragonite but also to calcium phosphate ceramics, particularly in bone sites with the large bone remodelling. Highlights: Black-Right-Pointing-Pointer Macroporous calcite manufacturing with controlled architecture as bone substitute Black-Right-Pointing-Pointer Cytotoxicity: adaptation of the colony-forming method with the target cells: MC3T3-E1 osteoblasts Black-Right-Pointing-Pointer Study of osteoblast proliferation and activity on calcite, HA and TCP.

Effect of heparin and alendronate coating on titanium surfaces on inhibition of osteoclast and enhancement of osteoblast function

Energy Technology Data Exchange (ETDEWEB)

Moon, Ho-Jin; Yun, Young-Pil [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Han, Choong-Wan; Kim, Min Sung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Sung Eun; Bae, Min Soo [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Gyu-Tae; Choi, Yong-Suk; Hwang, Eui-Hwan [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Lee, Joon Woo [Department of Technology Commercialization Information, Korea Institute of Science and Technology Information (KISTI), 66, Hoegi-ro, Dongdaemun-gu, Seoul 130-741 (Korea, Republic of); Lee, Jin-Moo; Lee, Chang-Hoon [Department of Oriental Gynecology, College of Oriental Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Duck-Su [Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kwon, Il Keun, E-mail: kwoni@khu.ac.kr [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

2011-09-23

Highlights: {yields} We examine bone metabolism of engineered alendronate attached to Ti surfaces. {yields} Alendronate-immobilized Ti enhances activation of osteoblast differentiation. {yields} Alendronate-immobilized Ti inhibits osteoclast differentiation. {yields} Alendronate-immobilized Ti may be a bioactive implant with dual functions. -- Abstract: The failure of orthopedic and dental implants has been attributed mainly to loosening of the implant from host bone, which may be due to weak bonding of the implant material to bone tissue. Titanium (Ti) is used in the field of orthopedic and dental implants because of its excellent biocompatibility and outstanding mechanical properties. Therefore, in the field of materials science and tissue engineering, there has been extensive research to immobilize bioactive molecules on the surface of implant materials in order to provide the implants with improved adhesion to the host bone tissue. In this study, chemically active functional groups were introduced on the surface of Ti by a grafting reaction with heparin and then the Ti was functionalized by immobilizing alendronate onto the heparin-grafted surface. In the MC3T3-E1 cell osteogenic differentiation study, the alendronate-immobilized Ti substrates significantly enhanced alkaline phosphatase activity (ALP) and calcium content. Additionally, nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation of RAW264.7 cells was inhibited with the alendronate-immobilized Ti as confirmed by TRAP analysis. Real time PCR analysis showed that mRNA expressions of osteocalcin and osteopontin, which are markers for osteogenesis, were upregulated in MC3T3-E1 cells cultured on alendronate-immobilized Ti. The mRNA expressions of TRAP and Cathepsin K, markers for osteoclastogenesis, in RAW264.7 cells cultured on alendronate-immobilized Ti were down-regulated. Our study suggests that alendronate-immobilized Ti may be a bioactive implant with dual functions to enhance

Pathogenesis of the Metabolic Syndrome: Insights from Monogenic Disorders

Directory of Open Access Journals (Sweden)

Rinki Murphy

2013-01-01

Full Text Available Identifying rare human metabolic disorders that result from a single-gene defect has not only enabled improved diagnostic and clinical management of such patients, but also has resulted in key biological insights into the pathophysiology of the increasingly prevalent metabolic syndrome. Insulin resistance and type 2 diabetes are linked to obesity and driven by excess caloric intake and reduced physical activity. However, key events in the causation of the metabolic syndrome are difficult to disentangle from compensatory effects and epiphenomena. This review provides an overview of three types of human monogenic disorders that result in (1 severe, non-syndromic obesity, (2 pancreatic beta cell forms of early-onset diabetes, and (3 severe insulin resistance. In these patients with single-gene defects causing their exaggerated metabolic disorder, the primary defect is known. The lessons they provide for current understanding of the molecular pathogenesis of the common metabolic syndrome are highlighted.

Proteolytic regulation of metabolic enzymes by E3 ubiquitin ligase complexes: lessons from yeast.

Science.gov (United States)

Nakatsukasa, Kunio; Okumura, Fumihiko; Kamura, Takumi

2015-01-01

Eukaryotic organisms use diverse mechanisms to control metabolic rates in response to changes in the internal and/or external environment. Fine metabolic control is a highly responsive, energy-saving process that is mediated by allosteric inhibition/activation and/or reversible modification of preexisting metabolic enzymes. In contrast, coarse metabolic control is a relatively long-term and expensive process that involves modulating the level of metabolic enzymes. Coarse metabolic control can be achieved through the degradation of metabolic enzymes by the ubiquitin-proteasome system (UPS), in which substrates are specifically ubiquitinated by an E3 ubiquitin ligase and targeted for proteasomal degradation. Here, we review select multi-protein E3 ligase complexes that directly regulate metabolic enzymes in Saccharomyces cerevisiae. The first part of the review focuses on the endoplasmic reticulum (ER) membrane-associated Hrd1 and Doa10 E3 ligase complexes. In addition to their primary roles in the ER-associated degradation pathway that eliminates misfolded proteins, recent quantitative proteomic analyses identified native substrates of Hrd1 and Doa10 in the sterol synthesis pathway. The second part focuses on the SCF (Skp1-Cul1-F-box protein) complex, an abundant prototypical multi-protein E3 ligase complex. While the best-known roles of the SCF complex are in the regulation of the cell cycle and transcription, accumulating evidence indicates that the SCF complex also modulates carbon metabolism pathways. The increasing number of metabolic enzymes whose stability is directly regulated by the UPS underscores the importance of the proteolytic regulation of metabolic processes for the acclimation of cells to environmental changes.

Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

International Nuclear Information System (INIS)

Godoy-Gallardo, Maria; Guillem-Marti, Jordi; Sevilla, Pablo; Manero, José M.; Gil, Francisco J.

2016-01-01

Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

Anhydride-functional silane immobilized onto titanium surfaces induces osteoblast cell differentiation and reduces bacterial adhesion and biofilm formation

Energy Technology Data Exchange (ETDEWEB)

Godoy-Gallardo, Maria, E-mail: maria.godoy.gallardo@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Guillem-Marti, Jordi, E-mail: jordi.guillem.marti@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Sevilla, Pablo, E-mail: psevilla@euss.es [Department of Mechanics, Escola Universitària Salesiana de Sarrià (EUSS), C/ Passeig de Sant Bosco, 42, 08017 Barcelona (Spain); Manero, José M., E-mail: jose.maria.manero@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); Gil, Francisco J., E-mail: francesc.xavier.gil@upc.edu [Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgy, Technical University of Catalonia (UPC), ETSEIB, Av. Diagonal 647, 08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE) — UPC, C/ Pascual i Vila 15, 08028 Barcelona (Spain); and others

2016-02-01

Bacterial infection in dental implants along with osseointegration failure usually leads to loss of the device. Bioactive molecules with antibacterial properties can be attached to titanium surfaces with anchoring molecules such as silanes, preventing biofilm formation and improving osseointegration. Properties of silanes as molecular binders have been thoroughly studied, but research on the biological effects of these coatings is scarce. The aim of the present study was to determine the in vitro cell response and antibacterial effects of triethoxysilypropyl succinic anhydride (TESPSA) silane anchored on titanium surfaces. X-ray photoelectron spectroscopy confirmed a successful silanization. The silanized surfaces showed no cytotoxic effects. Gene expression analyses of Sarcoma Osteogenic (SaOS-2) osteoblast-like cells cultured on TESPSA silanized surfaces reported a remarkable increase of biochemical markers related to induction of osteoblastic cell differentiation. A manifest decrease of bacterial adhesion and biofilm formation at early stages was observed on treated substrates, while favoring cell adhesion and spreading in bacteria–cell co-cultures. Surfaces treated with TESPSA could enhance a biological sealing on implant surfaces against bacteria colonization of underlying tissues. Furthermore, it can be an effective anchoring platform of biomolecules on titanium surfaces with improved osteoblastic differentiation and antibacterial properties. - Highlights: • TESPSA silane induces osteoblast differentiation. • TESPSA reduces bacterial adhesion and biofilm formation. • TESPSA is a promising anchoring platform of biomolecules onto titanium.

Porphyromonas endodontalis lipopolysaccharides induce RANKL by mouse osteoblast in a way different from that of Escherichia coli lipopolysaccharide.

Science.gov (United States)

Tang, Yin; Sun, Feifei; Li, Xiaoting; Zhou, Yuan; Yin, Shihai; Zhou, Xuedong

2011-12-01

Porphyromonas endodontalis lipopolysaccharide (LPS) has been shown to have a high positive rate in infected root canals and symptomatic apical periodontitis. It may play an integral role as a potent stimulator of inflammatory cytokines involved in apical lesions. The receptor activator of nuclear factor-κB ligand (RANKL) has been proven to be the key regulator of bone remodeling. This study investigated P. endodontalis LPS-induced RANKL production and LPS signaling in mouse osteoblasts. LPS-induced RANKL production in mouse osteoblast MC3T3-E1 cells was measured by Western blot and real-time polymerase chain reaction, and the Toll-like receptors (TLRs) were determined by the blocking test using anti-TLRs antibodies. In addition, specific inhibitors were used to analyze the intracellular signaling pathways. Escherichia coli LPS was used as the control. Both of the anti-TLR2 and anti-TLR4 antibodies significantly (P endodontalis LPS; only anti-TLR2 antibody had a significant (P endodontalis LPS-infected osteoblasts (P endodontalis LPS has the ability to promote the expression of RANKL in mouse osteoblasts, and this induction was mainly through the TLR2/4-JNK signaling pathway, a situation quite different from that of typical bacterial endotoxin (E. coli LPS). Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The role of nanocrystalline titania coating on nanostructured austenitic stainless steel in enhancing osteoblasts functions for regeneration of tissue

Energy Technology Data Exchange (ETDEWEB)

Shah, J.S.; Venkatsurya, P.K.C.; Thein-Han, W.W. [Biomaterials and Biomedical Engineering Research Laboratory, Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504 (United States); Misra, R.D.K., E-mail: dmisra@louisiana.edu [Biomaterials and Biomedical Engineering Research Laboratory, Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504 (United States); Pesacreta, T.C. [Department of Biology, University of Louisiana at Lafayette, P.O. Box 42451, Lafayette, LA 70504 (United States); Somani, M.C.; Karjalainen, L.P. [Department of Mechanical Engineering, University of Oulu, P.O. Box 4200, 90014 Oulu (Finland)

2011-03-12

In the context of osseointegration of metallic implants, while nanostructuring the surface favorably modulates cellular response, the disinfective attributes required during the healing process are not available. Thus, in the present study, we demonstrate that nanocrystalline titania provides cumulative benefit of enhancing osteoblasts functions to promote the efficacy of metal implants together with the disinfective attributes. To this end, the primary objective here is to examine the select functions of bone forming cells (osteoblasts) on electrocrystallized nanonodular titania-coated nanograined/ultrafine grained (NG/UFG) austenitic stainless steel. The accompanying objective is to study the disinfective/antimicrobial activity. To the best of our understanding this is the first study of nanophase titania on a non-titanium substrate. The osteoblasts functions were investigated in terms of cell attachment, proliferation, and quantitative analysis of proteins, actin and vinculin. In comparison to the bare NG/UFG substrate, the nanophase titania-coated substrate exhibited higher degree of cell attachment and proliferation which are regulated via cellular and molecular interactions with proteins, actin and vinculin. The enhanced functions of osteoblasts suggest that nanophase titania adsorbs extracellular matrix proteins, fibronectin and vitronectin from serum enhancing protein, with subsequent binding of integrins and osteoblasts precursor to titania. The antimicrobial attributes assessed in terms of degradation of methyl orange and effectiveness in killing E. coli supports the viewpoint that large surface area of titania would be instrumental in reducing the detrimental effect of biologically reactive oxygen species produced by macrophages in the vicinity of the metal bone/implant interface. In summary, the study provides some new insights concerning nanostructuring of metallic substrates with specific physical and surface properties for medical devices with

The effects of BIG-3 on osteoblast differentiation are not dependent upon endogenously produced BMPs

International Nuclear Information System (INIS)

Gori, Francesca; Demay, Marie B.

2005-01-01

BMPs play an important role in both intramembranous and endochondral ossification. BIG-3, BMP-2-induced gene 3 kb, encodes a WD-40 repeat protein that accelerates the program of osteoblastic differentiation in vitro. To examine the potential interactions between BIG-3 and the BMP-2 pathway during osteoblastic differentiation, MC3T3-E1 cells stably transfected with BIG-3 (MC3T3E1-BIG-3), or with the empty vector (MC3T3E1-EV), were treated with noggin. Noggin treatment of pooled MC3T3E1-EV clones inhibited the differentiation-dependent increase in AP activity observed in the untreated MC3T3E1-EV clones but did not affect the increase in AP activity in the MC3T3E1-BIG-3 clones. Noggin treatment decreased the expression of Runx2 and type I collagen mRNAs and impaired mineralized matrix formation in MC3T3E1-EV clones but not in MC3T3E1-BIG-3 clones. To determine whether the actions of BIG-3 on osteoblast differentiation converged upon the BMP pathway or involved an alternate signaling pathway, Smad1 phosphorylation was examined. Basal phosphorylation of Smad1 was not altered in the MC3T3E1-BIG-3 clones. However, these clones did not exhibit the noggin-dependent decrease in phosphoSmad1 observed in the MC3T3E1-EV clones, nor did it decrease nuclear localization of phosphoSmad1. These observations suggest that BIG-3 accelerates osteoblast differentiation in MC3T3-E1 cells by inducing phosphorylation and nuclear translocation of Smad1 independently of endogenously produced BMPs

Abnormal arrangement of a collagen/apatite extracellular matrix orthogonal to osteoblast alignment is constructed by a nanoscale periodic surface structure.

Science.gov (United States)

Matsugaki, Aira; Aramoto, Gento; Ninomiya, Takafumi; Sawada, Hiroshi; Hata, Satoshi; Nakano, Takayoshi

2015-01-01

Morphological and directional alteration of cells is essential for structurally appropriate construction of tissues and organs. In particular, osteoblast alignment is crucial for the realization of anisotropic bone tissue microstructure. In this article, the orientation of a collagen/apatite extracellular matrix (ECM) was established by controlling osteoblast alignment using a surface geometry with nanometer-sized periodicity induced by laser ablation. Laser irradiation induced self-organized periodic structures (laser-induced periodic surface structures; LIPSS) with a spatial period equal to the wavelength of the incident laser on the surface of biomedical alloys of Ti-6Al-4V and Co-Cr-Mo. Osteoblast orientation was successfully induced parallel to the grating structure. Notably, both the fibrous orientation of the secreted collagen matrix and the c-axis of the produced apatite crystals were orientated orthogonal to the cell direction. To the best of our knowledge, this is the first report demonstrating that bone tissue anisotropy is controllable, including the characteristic organization of a collagen/apatite composite orthogonal to the osteoblast orientation, by controlling the cell alignment using periodic surface geometry. Copyright © 2014 Elsevier Ltd. All rights reserved.

The history of a lesson

DEFF Research Database (Denmark)

Rasmussen, Mikkel Vedby

2003-01-01

and emphasises the need to study the history of lessons rather than the lessons of history. This approach shows that Munich is the end point of a constitutive history that begins in the failure of the Versailles treaty to create a durable European order following the First World War. The Munich lesson is thus......The article investigates the concept of lessons in IR. By means of a constructivist critique of the 'lessons literature', the article analyses one of the most important of IR lessons: that of Munich. Examining how the Munich lesson came about, the article shows the praxeological nature of lessons...... one element of the lesson of Versailles, which is a praxeology that defines how the West is to make peace, and against whom peace must be defended. The lesson of Versailles has been, at least in part, constitutive of the outbreak of the Cold War, and it continues to define the Western conception...

SPILANTHES ACMELLA AND PHYSICAL EXERCISE INCREASED TESTOSTERONE LEVELS AND OSTEOBLAST CELLS IN GLUCOCORTICOID-INDUCED OSTEOPOROSIS MALE MICE

Directory of Open Access Journals (Sweden)

Hening Laswati

2015-08-01

Full Text Available Background: Glucocorticoid-induced osteoporosis is leading cause of secondary osteoporosis by decreasing formation activity and increasing resorption activity. Spilanthes acmella, is one of Indonesia medicinal plants that contain of polyphenol and flavonoids. Previously in vitro study showed that buthanol and water fraction from this plant have increased alkaline phosphatase that known as marker of bone formation. The objective of this study to analyze the effect of Spilanthes acmella  and physical exercise in increasing testosterone and  osteoblast cells of femoral’s trabecular glucocorticoid-induced osteoporosis male mice. Method: This study using a posttest control group design, 36 male healthy mice (5 months old  were randomizely devided into 6 groups, there are : 1.Healthy control group (without induction dexamethaxone, 2.Osteoporosis groups (induction with dexamethaxone without treatment, 3.Positive control receive suspension alendronat, 4.70% Ethanol extract of Spilanthes acmella group, 5.Combination group of 70% extract ethanol of Spilanthes acmella and exercise, and 6.Exercise group  (walking using mice treadmill 10m/minute, 5-12 minutes 3 times a week. All of the intervention were given for 4 weeks. The serum levels of testosterone were determined using  immunoserology (ELISA and osteoblast cells were determined histomorphometry by light microscopy.  All statistical test were carried out using SPSS 23 and statistical significance was  set at p<0.05 for all analysis. The testosterone levels  between group were compared using Mann-Whitney test and osteoblast cells between group were compared with multiple comparison. Results: It showed that the alendronate group, combination group and the exercise group increasing testosterone level (p<0.05 from that osteoporotic group. There were also increasing osteoblast cells (p<0.05 in the alendronate group and combination group. There was no correlation between testosterone level and

Lesson Learning at JPL

Science.gov (United States)

Oberhettinger, David

2011-01-01

A lessons learned system is a hallmark of a mature engineering organization A formal lessons learned process can help assure that valuable lessons get written and published, that they are well-written, and that the essential information is "infused" into institutional practice. Requires high-level institutional commitment, and everyone's participation in gathering, disseminating, and using the lessons

A role for the retinoblastoma protein as a regulator of mouse osteoblast cell adhesion: implications for osteogenesis and osteosarcoma formation.

Directory of Open Access Journals (Sweden)

Bernadette Sosa-García

2010-11-01

Full Text Available The retinoblastoma protein (pRb is a cell cycle regulator inactivated in most human cancers. Loss of pRb function results from mutations in the gene coding for pRb or for any of its upstream regulators. Although pRb is predominantly known as a cell cycle repressor, our data point to additional pRb functions in cell adhesion. Our data show that pRb regulates the expression of a wide repertoire of cell adhesion genes and regulates the assembly of the adherens junctions required for cell adhesion. We conducted our studies in osteoblasts, which depend on both pRb and on cell-to-cell contacts for their differentiation and function. We generated knockout mice in which the RB gene was excised specifically in osteoblasts using the cre-lox P system and found that osteoblasts from pRb knockout mice did not assemble adherens junction at their membranes. pRb depletion in wild type osteoblasts using RNAi also disrupted adherens junctions. Microarrays comparing pRb-expressing and pRb-deficient osteoblasts showed that pRb controls the expression of a number of cell adhesion genes, including cadherins. Furthermore, pRb knockout mice showed bone abnormalities consistent with osteoblast adhesion defects. We also found that pRb controls the function of merlin, a well-known regulator of adherens junction assembly, by repressing Rac1 and its effector Pak1. Using qRT-PCR, immunoblots, co-immunoprecipitation assays, and immunofluorescent labeling, we observed that pRb loss resulted in Rac1 and Pak1 overexpression concomitant with merlin inactivation by Pak1, merlin detachment from the membrane, and adherens junction loss. Our data support a pRb function in cell adhesion while elucidating the mechanism for this function. Our work suggests that in some tumor types pRb inactivation results in both a loss of cell cycle control that promotes initial tumor growth as well as in a loss of cell-to-cell contacts, which contributes to later stages of metastasis.

Neuropeptide Y, substance P, and human bone morphogenetic protein 2 stimulate human osteoblast osteogenic activity by enhancing gap junction intercellular communication

Energy Technology Data Exchange (ETDEWEB)

Ma, W.H.; Liu, Y.J.; Wang, W.; Zhang, Y.Z. [The Third Hospital of Hebei Medical University, The Provincial Key Laboratory for Orthopedic Biomechanics of Hebei, Shijiazhuang, Hebei Province (China)

2015-02-13

Bone homeostasis seems to be controlled by delicate and subtle “cross talk” between the nervous system and “osteo-neuromediators” that control bone remodeling. The purpose of this study was to evaluate the effect of interactions between neuropeptides and human bone morphogenetic protein 2 (hBMP2) on human osteoblasts. We also investigated the effects of neuropeptides and hBMP2 on gap junction intercellular communication (GJIC). Osteoblasts were treated with neuropeptide Y (NPY), substance P (SP), or hBMP2 at three concentrations. At various intervals after treatment, cell viability was measured by the MTT assay. In addition, cellular alkaline phosphatase (ALP) activity and osteocalcin were determined by colorimetric assay and radioimmunoassay, respectively. The effects of NPY, SP and hBMP on GJIC were determined by laser scanning confocal microscopy. The viability of cells treated with neuropeptides and hBMP2 increased significantly in a time-dependent manner, but was inversely associated with the concentration of the treatments. ALP activity and osteocalcin were both reduced in osteoblasts exposed to the combination of neuropeptides and hBMP2. The GJIC of osteoblasts was significantly increased by the neuropeptides and hBMP2. These results suggest that osteoblast activity is increased by neuropeptides and hBMP2 through increased GJIC. Identification of the GJIC-mediated signal transduction capable of modulating the cellular activities of bone cells represents a novel approach to studying the biology of skeletal innervation.

Neuropeptide Y, substance P, and human bone morphogenetic protein 2 stimulate human osteoblast osteogenic activity by enhancing gap junction intercellular communication

International Nuclear Information System (INIS)

Ma, W.H.; Liu, Y.J.; Wang, W.; Zhang, Y.Z.

2015-01-01

Bone homeostasis seems to be controlled by delicate and subtle “cross talk” between the nervous system and “osteo-neuromediators” that control bone remodeling. The purpose of this study was to evaluate the effect of interactions between neuropeptides and human bone morphogenetic protein 2 (hBMP2) on human osteoblasts. We also investigated the effects of neuropeptides and hBMP2 on gap junction intercellular communication (GJIC). Osteoblasts were treated with neuropeptide Y (NPY), substance P (SP), or hBMP2 at three concentrations. At various intervals after treatment, cell viability was measured by the MTT assay. In addition, cellular alkaline phosphatase (ALP) activity and osteocalcin were determined by colorimetric assay and radioimmunoassay, respectively. The effects of NPY, SP and hBMP on GJIC were determined by laser scanning confocal microscopy. The viability of cells treated with neuropeptides and hBMP2 increased significantly in a time-dependent manner, but was inversely associated with the concentration of the treatments. ALP activity and osteocalcin were both reduced in osteoblasts exposed to the combination of neuropeptides and hBMP2. The GJIC of osteoblasts was significantly increased by the neuropeptides and hBMP2. These results suggest that osteoblast activity is increased by neuropeptides and hBMP2 through increased GJIC. Identification of the GJIC-mediated signal transduction capable of modulating the cellular activities of bone cells represents a novel approach to studying the biology of skeletal innervation

Reconstruction of rat calvarial defects with human mesenchymal stem cells and osteoblast-like cells in poly-lactic-co-glycolic acid scaffolds

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C Zong

2010-09-01

Full Text Available Human mesenchymal stem cells (hMSCs can be used for xenogenic transplantation due to their low immunogenicity, high proliferation rate, and multi-differentiation potentials. Therefore, hMSCs are an ideal seeding source for tissue engineering. The present study evaluates the reconstruction effects of hMSCs and osteoblast-like cells differentiated from hMSCs in poly-lactic-co-glycolic acid (PLGA scaffolds on the calvarial defect of rats. Two bilateral full-thickness defects (5mm in diameter were created in the calvarium of nonimmunosuppressed Sprague-Dawley rats. The defects were filled by PLGA scaffolds with hMSCs (hMSC Construct or with osteoblast-like cells differentiated from hMSCs (Osteoblast Construct. The defects without any graft (Blank Defect or filled with PLGA scaffold without any cells (Blank Scaffold were used as controls. Evaluation was performed using macroscopic view, histology and immunohistochemical analysis respectively at 10 and 20 weeks after transplantation. In addition, fluorescent carbocyanine CM-Dil was used to track the implanted cells in vivo during transplantation. The results showed that while both hMSC Construct and Osteoblast Construct led to an effective reconstruction of critical-size calvarial defects, the bone reconstruction potential of hMSC Construct was superior to that of Osteoblast Construct in non-autogenous applications. Our findings verify the feasibility of the use of xenogenic MSCs for tissue engineering and demonstrate that undifferentiated hMSCs are more suitable for bone reconstruction in xenotransplantation models.

The role of osteoblast cells in the pathogenesis of unicameral bone cysts.

Science.gov (United States)

Aarvold, Alexander; Smith, James O; Tayton, Edward R; Edwards, Caroline J; Fowler, Darren J; Gent, Edward D; Oreffo, Richard O C

2012-08-01

The pathogenesis of unicameral bone cysts (UBCs) remains largely unknown. Osteoclasts have been implicated, but the role of osteoblastic cells has, to date, not been explored. This study investigated the pathophysiology of UBCs by examining the interactions between the cyst fluid and human bone marrow stromal cells (hBMSCs) and the effect of the fluid on osteogenesis. Fluid was aspirated from two UBCs and analysed for protein, electrolyte and cytokine levels. Graded concentrations of the fluid were used as culture media for hBMSCs to determine the effects of the fluid on hBMSC proliferation and osteogenic differentiation. The fibrocellular lining was analysed histologically and by electron microscopy. Alkaline phosphatase (ALP) staining of hBMSCs that were cultured in cyst fluid demonstrated increased cell proliferation and osteogenic differentiation compared to basal media controls. Biochemical analysis of these hBMSCs compared to basal controls confirmed a marked increase in DNA content (as a marker of proliferation) and ALP activity (as a marker of osteogenic differentiation) which was highly significant (p < 0.001). Osteoclasts were demonstrated in abundance in the cyst lining. The cyst fluid cytokine profile revealed levels of the pro-osteoclast cytokines IL-6, MIP-1α and MCP-1 that were 19×, 31× and 35× greater than those in reference serum. Cyst fluid promoted osteoblastic growth and differentiation. Despite appearing paradoxical that the cyst fluid promoted osteogenesis, osteoblastic cells are required for osteoclastogenesis through RANKL signalling. Three key cytokines in this pathway (IL-6, MIP-1α, MCP-1) were highly elevated in cyst fluid. These findings may hold the key to the pathogenesis of UBCs, with implications for treatment methods.

Pulsed electromagnetic fields increased the anti-inflammatory effect of A₂A and A₃ adenosine receptors in human T/C-28a2 chondrocytes and hFOB 1.19 osteoblasts.

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Fabrizio Vincenzi

Full Text Available Adenosine receptors (ARs have an important role in the regulation of inflammation and their activation is involved in the inhibition of pro-inflammatory cytokine release. The effects of pulsed electromagnetic fields (PEMFs on inflammation have been reported and we have demonstrated that PEMFs increased A2A and A3AR density and functionality in different cell lines. Chondrocytes and osteoblasts are two key cell types in the skeletal system that play important role in cartilage and bone metabolism representing an interesting target to study the effect of PEMFs. The primary aim of the present study was to evaluate if PEMF exposure potentiated the anti-inflammatory effect of A2A and/or A3ARs in T/C-28a2 chondrocytes and hFOB 1.19 osteoblasts. Immunofluorescence, mRNA analysis and saturation binding assays revealed that PEMF exposure up-regulated A2A and A3AR expression. A2A and A3ARs were able to modulate cAMP production and cell proliferation. The activation of A2A and A3ARs resulted in the decrease of some of the most relevant pro-inflammatory cytokine release such as interleukin (IL-6 and IL-8, following the treatment with IL-1β as an inflammatory stimuli. In human chondrocyte and osteoblast cell lines, the inhibitory effect of A2A and A3AR stimulation on the release of prostaglandin E2 (PGE2, an important lipid inflammatory mediator, was observed. In addition, in T/C-28a2 cells, the activation of A2A or A3ARs elicited an inhibition of vascular endothelial growth factor (VEGF secretion. In hFOB 1.19 osteoblasts, PEMF exposure determined an increase of osteoprotegerin (OPG production. The effect of the A2A or A3AR agonists in the examined cells was enhanced in the presence of PEMFs and completely blocked by using well-known selective antagonists. These results demonstrated that PEMF exposure significantly increase the anti-inflammatory effect of A2A or A3ARs suggesting their potential therapeutic use in the therapy of inflammatory bone and joint

In the trail of a new bio-sensor for measuring strain in bone: osteoblastic biocompatibility.

Science.gov (United States)

Carvalho, Lídia; Alberto, Nélia J; Gomes, Pedro S; Nogueira, Rogério N; Pinto, João L; Fernandes, Maria H

2011-06-15

Fibre Bragg Grating (FBG) is an optical sensor recorded within the core of a standard optical fibre, which responds faithfully to strain and temperature. FBG sensors are a promising alternative to other sensing methodologies to assess bone mechanics in vivo. However, response of bone cells/bone tissue to FBGs and its sensing capability in this environment have not been recorded yet. The present study addressed these issues in long-term human osteoblastic cell cultures. Results showed that osteoblastic cells were able to adhere and proliferate over the fibre and, also, the protective polymer coating. RT-PCR analysis showed the expression of Col I, ALP, BMP-2, M-CSF, RANKL and OPG. In addition, cultures presented high ALP activity and the formation of a calcium phosphate mineralized extracellular matrix. Cell behavior over the fibre without and with the coating polymer was similar to that found in cultures grown in standard tissue culture plates (control). In addition to the excellent osteoblastic cytocompatibility, FBGs maintained the physical integrity and functionality, as its sensing capability was not affected through the culture period. Results suggest the possibility of in vivo osseointegration of the optical fibre/FBGs anticipating a variety of applications in bone mechanical dynamics. Copyright © 2011 Elsevier B.V. All rights reserved.

Temporal Profiling and Pulsed SILAC Labeling Identify Novel Secreted Proteins during ex vivo Osteoblast Differentiation of Human Stromal Stem Cells

DEFF Research Database (Denmark)

Kristensen, Lars P; Chen, Li; Nielsen, Maria Overbeck

2012-01-01

, is not fully established. To address these questions, we quantified the temporal dynamics of the human stromal (mesenchymal, skeletal) stem cell (hMSC) secretome during ex vivo OB differentiation using stable isotope labeling by amino acids in cell culture (SILAC). In addition, we employed pulsed SILAC...... the identification of novel factors produced by hMSC with potential role in OB differentiation. Our study demonstrates that the secretome of osteoblastic cells is more complex than previously reported and supports the emerging evidence that osteoblastic cells secrete proteins with endocrine functions and regulate...... regulators of OB differentiation. Furthermore, we studied the biological effects of one of these proteins, the hormone stanniocalcin 2 (STC2) and demonstrated its autocrine effects in enhancing osteoblastic differentiation of hMSC. In conclusion, combining complete and pulsed SILAC labeling facilitated...

Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability

International Nuclear Information System (INIS)

Yang, Seung Yun; Kim, Eung-Sam; Jeon, Gumhye; Choi, Kwan Yong; Kim, Jin Kon

2013-01-01

We independently controlled surface topography and wettability of polystyrene (PS) films by CF 4 and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF 4 plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ∼ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering. Highlights: ► New approach based on plasma treatment to independently control the surface topography and wettability ► The adhesion of human fetal osteoblast (hFOB) was enhanced on a surface with an average roughness of ∼ 11 nm. ► The adhesion and proliferation of hFOB was maximized when nanotextured surface became highly hydrophilic

Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability

Energy Technology Data Exchange (ETDEWEB)

Yang, Seung Yun [National Creative Research Center for Block Copolymer Self-Assembly, Departments of Environmental Science and Engineering and Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Kim, Eung-Sam [School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Jeon, Gumhye [National Creative Research Center for Block Copolymer Self-Assembly, Departments of Environmental Science and Engineering and Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Choi, Kwan Yong, E-mail: kchoi@postech.ac.kr [School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); Kim, Jin Kon, E-mail: jkkim@postech.ac.kr [National Creative Research Center for Block Copolymer Self-Assembly, Departments of Environmental Science and Engineering and Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

2013-04-01

We independently controlled surface topography and wettability of polystyrene (PS) films by CF{sub 4} and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF{sub 4} plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ∼ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering. Highlights: ► New approach based on plasma treatment to independently control the surface topography and wettability ► The adhesion of human fetal osteoblast (hFOB) was enhanced on a surface with an average roughness of ∼ 11 nm. ► The adhesion and proliferation of hFOB was maximized when nanotextured surface became highly hydrophilic.

Quantitative metabolic imaging using endogenous fluorescence to detect stem cell differentiation

Science.gov (United States)

Quinn, Kyle P.; Sridharan, Gautham V.; Hayden, Rebecca S.; Kaplan, David L.; Lee, Kyongbum; Georgakoudi, Irene

2013-12-01

The non-invasive high-resolution spatial mapping of cell metabolism within tissues could provide substantial advancements in assessing the efficacy of stem cell therapy and understanding tissue development. Here, using two-photon excited fluorescence microscopy, we elucidate the relationships among endogenous cell fluorescence, cell redox state, and the differentiation of human mesenchymal stem cells into adipogenic and osteoblastic lineages. Using liquid chromatography/mass spectrometry and quantitative PCR, we evaluate the sensitivity of an optical redox ratio of FAD/(NADH + FAD) to metabolic changes associated with stem cell differentiation. Furthermore, we probe the underlying physiological mechanisms, which relate a decrease in the redox ratio to the onset of differentiation. Because traditional assessments of stem cells and engineered tissues are destructive, time consuming, and logistically intensive, the development and validation of a non-invasive, label-free approach to defining the spatiotemporal patterns of cell differentiation can offer a powerful tool for rapid, high-content characterization of cell and tissue cultures.

Ca uptake and its influence by growth hormone in osteoblasts of fetal rat calvaria

International Nuclear Information System (INIS)

Wang Hongfu; Jin Weifang; Sekimoto Haku

1994-01-01

Uptake and release of Ca 2+ are important functions of osteoblasts. In the paper we studied the uptake of calcium and influence by Growth Hormone in osteoblasts of fetal rat calvaria by liquid scintillation spectrometry of 45 Ca 2+ . In short-term cultures of the bone derived cells, the uptake of 45 Ca 2+ increased steadily. The activity of 45 Ca 2+ in the cells of 15 minute cultures was 2∼3 times of that in the 0 minute cultures. It continued to increase in the cells of 30 minute cultures. Exposure of the bone cells to GH at 55.3 ng/ml increased the uptake of 45 Ca 2+ by 2.3 times in the 30 minute cultures and 1.5 times in the 60 minute cultures than those of the control

Bone conditioned media (BCM) improves osteoblast adhesion and differentiation on collagen barrier membranes.

Science.gov (United States)

Fujioka-Kobayashi, Masako; Caballé-Serrano, Jordi; Bosshardt, Dieter D; Gruber, Reinhard; Buser, Daniel; Miron, Richard J

2016-07-04

The use of autogenous bone chips during guided bone regeneration procedures has remained the gold standard for bone grafting due to its excellent combination of osteoconduction, osteoinduction and osteogenesis. Recent protocols established by our group have characterized specific growth factors and cytokines released from autogenous bone that have the potential to be harvested and isolated into bone conditioned media (BCM). Due to the advantageous osteo-promotive properties of BCM, the aims of the present study was to pre-coat collagen barrier membranes with BCM and investigate its effect on osteoblast adhesion, proliferation and differentiation for possible future clinical use. Scanning electron microscopy (SEM) was first used to qualitative assess BCM protein accumulation on the surface of collagen membranes. Thereafter, undifferentiated mouse ST2 stromal bone marrow cells were seeded onto BioGide porcine derived collagen barrier membranes (control) or barrier membranes pre-coated with BCM (test group). Control and BCM samples were compared for cell adhesion at 8 h, cell proliferation at 1, 3 and 5 days and real-time PCR at 5 days for osteoblast differentiation markers including Runx2, alkaline phosphatase (ALP), osteocalcin (OCN) and bone sialoprotein (BSP). Mineralization was further assessed with alizarin red staining at 14 days post seeding. SEM images demonstrated evidence of accumulated proteins found on the surface of collagen membranes following coating with BCM. Analysis of total cell numbers revealed that the additional pre-coating with BCM markedly increased cell attachment over 4 fold when compared to cells seeded on barrier membranes alone. No significant difference could be observed for cell proliferation at all time points. BCM significantly increased mRNA levels of osteoblast differentiation markers including ALP, OCN and BSP at 5 days post seeding. Furthermore, barrier membranes pre-coated with BCM demonstrated a 5-fold increase in alizarin

Further studies on the intermediary metabolism of bone in vitro and a monoclonal cell line (MMB-1) derived from bone: effects of parathyroid hormone and acetazolamide

International Nuclear Information System (INIS)

Nichols, F.C.

1981-01-01

The mechanism/mechanisms by which PTH affects Ca homeostasis between blood and bone have not been clearly established. Most studies of metabolic acid production in bone took place during the late 1950s and early 1960s. Since that time, assay techniques for metabolic acid production have been improved for greater sensitivity, more has been learned as to how PTH mediates its cellular responses, and techniques for cell isolation and culture have dramatically improved. These improvements have made possible new approaches to the study of short term effects of PTH on metabolic acid production in bone. Chapter 1 explores the potential of bone to utilize substrates other than glucose for metabolic energy transfer. Chapter 2 characterizes glucose metabolism in mouse calvaria in vitro and explores effects of PTH, acetazolamide, and C1 13,850 on calvaria oxidative metabolism. Chapter 3 describes PTH effects on glucose metabolism of MMB-1 cells, a monoclonal cell line reported to possess osteoblast-like characteristics

Osteoblastic response to pectin nanocoating on titanium surfaces

Energy Technology Data Exchange (ETDEWEB)

Gurzawska, Katarzyna, E-mail: kagu@sund.ku.dk [Research Center for Ageing and Osteoporosis, Departments of Medicine and Diagnostics, Copenhagen University Hospital Glostrup, Ndr. Ringvej 57, 2600 Glostrup (Denmark); Institute of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen, Nørre Allé 20, 2200 Copenhagen N (Denmark); Svava, Rikke [Department of Plant Environment Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Copenhagen Center for Glycomics, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N (Denmark); Yihua, Yu; Haugshøj, Kenneth Brian [Microtechnology and Surface Analysis, Danish Technological Institute, Gregersensvej 8, 2630 Taastrup (Denmark); Dirscherl, Kai [Dansk Fundamental Metrologi A/S, Matematiktorvet 307, 2800 Lyngby (Denmark); Levery, Steven B. [Copenhagen Center for Glycomics, Institute for Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N (Denmark); Byg, Inge [Department of Plant Environment Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Damager, Iben [Novozymes A/S, Krogshoejvej 36, 2880 Bagsvaerd (Denmark); Nielsen, Martin W. [Department of Systems Biology, Technical University of Denmark, Matematiktorvet, Building 301, Kgs. Lyngby DK-2800 (Denmark); Jørgensen, Bodil [Department of Plant Environment Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Jørgensen, Niklas Rye [Research Center for Ageing and Osteoporosis, Departments of Medicine and Diagnostics, Copenhagen University Hospital Glostrup, Ndr. Ringvej 57, 2600 Glostrup (Denmark); and others

2014-10-01

Osseointegration of titanium implants can be improved by organic and inorganic nanocoating of the surface. The aim of our study was to evaluate the effect of organic nanocoating of titanium surface with unmodified and modified pectin Rhamnogalacturonan-Is (RG-Is) isolated from potato and apple with respect to surface properties and osteogenic response in osteoblastic cells. Nanocoatings on titanium surfaces were evaluated by scanning electron microscopy, contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy. The effect of coated RG-Is on cell adhesion, cell viability, bone matrix formation and mineralization was tested using SaOS-2 cells. Nanocoating with pectin RG-Is affected surface properties and in consequence changed the environment for cellular response. The cells cultured on surfaces coated with RG-Is from potato with high content of linear 1.4-linked galactose produced higher level of mineralized matrix compared with control surfaces and surfaces coated with RG-I with low content of linear 1.4-linked galactose. The study showed that the pectin RG-Is nanocoating not only changed chemical and physical titanium surface properties, but also specific coating with RG-Is containing high amount of galactan increased mineralized matrix formation of osteoblastic cells in vitro. - Highlights: • Surface nanocoating with plant-derived Rhamnogalacturonan-I (RG-I) is proposed. • Titanium surface became more hydrophilic after RG-Is nanocoating. • RG-Is with high galactose content resulted in high level of mineralized matrix. • RG-I is a new candidate for improvement of bone healing and osseointegration.

Influence of sterilization methods on cell behavior and functionality of osteoblasts cultured on TiO2 nanotubes

International Nuclear Information System (INIS)

Oh, Seunghan; Brammer, Karla S.; Moon, Kyung-Suk; Bae, Ji-Myung; Jin, Sungho

2011-01-01

We investigated the adhesion, proliferation and osteogenic functionality of osteoblasts cultured on titanium dioxide (TiO 2 ) nanotubes in response to different sterilization methods (dry autoclaving vs. wet autoclaving). We prepared various sizes (30-100 nm diameter) of TiO 2 nanotubes on titanium substrates by anodization, sterilized nanotubes by different conditions, and seeded osteoblast cells onto the nanotube surfaces with two different cell seeding densities (10,000 vs. 50,000 cells/well in 12-culture well). The result of this study indicates that the adhesion, proliferation and alkaline phosphatase activity of osteoblasts cultured on only the larger 70 and 100 nm TiO 2 nanotube arrays were dramatically changed by the different sterilization conditions at a low cell seeding density. However, with a higher cell seeding density (50,000 cells/well in 12-cell culture well), the results revealed no significant difference among altered nanotube geometry, 30-100 nm diameters, nor sterilization methods. Next, it was revealed that the nanofeatures of proteins adhered on nanotubular TiO 2 morphology are altered by the sterilization method. It was determined that this protein adhesion effect, in combination with the cell density of osteoblasts seeded onto such TiO 2 nanotube surfaces, has profound effects on cell behavior. This study clearly shows that these are some of the important in vitro culture factors that need to be taken into consideration, as well as TiO 2 nanotube diameters which play an important role in the improvement of cell behavior and functionality.

Osteoblast interaction with DLC-coated Si substrates.

Science.gov (United States)

Chai, Feng; Mathis, Nicolas; Blanchemain, Nicolas; Meunier, Cathy; Hildebrand, Hartmut F

2008-09-01

Diamond-like carbon (DLC) coating is a convenient means of modifying material surfaces that are sensitive to wear, such as titanium and silica substrates. This work aims to evaluate the osteoblast-like cells' response to DLC-coated Si (Si-DLC), which was treated under different conditions. DLC and deuterated DLC films were deposited by plasma-enhanced chemical vapor deposition to obtain a 200-nm-thick layer on all the samples. Three types of precursor gas were applied for deposition: pure methane (CH(4)), pure deuterated methane (CD(4)) and their half/half mixture. All surface treatments were performed under two different self-bias voltages (V(sb)): -400 and -600V. The modified surfaces were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, Rutherford backscattering spectroscopy, elastic recoil detection analysis, X-ray reflectometry and the sessile-drop method. MC3T3-E1 osteoblasts were cultured on the Si-DLC wafers for 3 and 6 days. Biological tests to measure cell proliferation, cell vitality, cell morphology and cell adhesion were performed. All DLC coatings produced a slightly more hydrophobic state than non-treated Si. Certain types of amorphous DLC coating, such as the surface treated under the V(sb) of -600V in pure methane (600CH(4)) or in pure deuterated methane (600CD(4)), offered a significantly higher cell proliferation rate to Si substrate. Scanning electron microscopy observations confirmed that the optimal cell adhesion behavior, among all the treated surfaces, occurred on the surface of the 600CH(4) and 600CD(4) groups, which showed increased amounts of filopodia and microvilli to enhance cell-environment exchange. In conclusion, DLC coating on Si could produce better surface stability and improved cellular responses.

Myostatin inhibits osteoblastic differentiation by suppressing osteocyte-derived exosomal microRNA-218: A novel mechanism in muscle-bone communication.

Science.gov (United States)

Qin, Yiwen; Peng, Yuanzhen; Zhao, Wei; Pan, Jianping; Ksiezak-Reding, Hanna; Cardozo, Christopher; Wu, Yingjie; Divieti Pajevic, Paola; Bonewald, Lynda F; Bauman, William A; Qin, Weiping

2017-06-30

Muscle and bone are closely associated in both anatomy and function, but the mechanisms that coordinate their synergistic action remain poorly defined. Myostatin, a myokine secreted by muscles, has been shown to inhibit muscle growth, and the disruption of the myostatin gene has been reported to cause muscle hypertrophy and increase bone mass. Extracellular vesicle-exosomes that carry microRNA (miRNA), mRNA, and proteins are known to perform an important role in cell-cell communication. We hypothesized that myostatin may play a crucial role in muscle-bone interactions and may promote direct effects on osteocytes and on osteocyte-derived exosomal miRNAs, thereby indirectly influencing the function of other bone cells. We report herein that myostatin promotes expression of several bone regulators such as sclerostin (SOST), DKK1, and RANKL in cultured osteocytic (Ocy454) cells, concomitant with the suppression of miR-218 in both parent Ocy454 cells and derived exosomes. Exosomes produced by Ocy454 cells that had been pretreated with myostatin could be taken up by osteoblastic MC3T3 cells, resulting in a marked reduction of Runx2, a key regulator of osteoblastic differentiation, and in decreased osteoblastic differentiation via the down-regulation of the Wnt signaling pathway. Importantly, the inhibitory effect of myostatin-modified osteocytic exosomes on osteoblast differentiation is completely reversed by expression of exogenous miR-218, through a mechanism involving miR-218-mediated inhibition of SOST. Together, our findings indicate that myostatin directly influences osteocyte function and thereby inhibits osteoblastic differentiation, at least in part, through the suppression of osteocyte-derived exosomal miR-218, suggesting a novel mechanism in muscle-bone communication. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

The Role of Osteoblast-Derived Cytokines in Bone Metastatic Breast Cancer

Science.gov (United States)

2009-01-01

transform infrared microspectroscopy [34]. The MC3T3-E1 cultures, however, contained material of an unknown origin that represented dystrophic...x- ray densitometer (GE Medical Systems, Fitchburg, WI) and scanned via a Dual Energy X- ray Absorptiometry (DEXA) scan. Company-provided software...including osteoporosis, rheumatoid arthritis , and skeletal metastases, resulting in osteoclast activity in excess of bone deposition by osteoblasts with

The Role of Parathyroid Hormone-Related Protein (PTHrP in Osteoblast Response to Microgravity: Mechanistic Implications for Osteoporosis Development.

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Anne Camirand

Full Text Available Prolonged skeletal unloading through bedrest results in bone loss similar to that observed in elderly osteoporotic patients, but with an accelerated timeframe. This rapid effect on weight-bearing bones is also observed in astronauts who can lose up to 2% of their bone mass per month spent in Space. Despite the important implications for Spaceflight travelers and bedridden patients, the exact mechanisms involved in disuse osteoporosis have not been elucidated. Parathyroid hormone-related protein (PTHrP regulates many physiological processes including skeletal development, and has been proposed as a mechanosensor. To investigate the role of PTHrP in microgravity-induced bone loss, trabecular and calvarial osteoblasts (TOs and COs from Pthrp +/+ and -/- mice were subjected to actual Spaceflight for 6 days (Foton M3 satellite. Pthrp +/+, +/- and -/- osteoblasts were also exposed to simulated microgravity for periods varying from 6 days to 6 weeks. While COs displayed little change in viability in 0g, viability of all TOs rapidly decreased in inverse proportion to PTHrP expression levels. Furthermore, Pthrp+/+ TOs displayed a sharp viability decline after 2 weeks at 0g. Microarray analysis of Pthrp+/+ TOs after 6 days in simulated 0g revealed expression changes in genes encoding prolactins, apoptosis/survival molecules, bone metabolism and extra-cellular matrix composition proteins, chemokines, insulin-like growth factor family members and Wnt-related signalling molecules. 88% of 0g-induced expression changes in Pthrp+/+ cells overlapped those caused by Pthrp ablation in normal gravity, and pulsatile treatment with PTHrP1-36 not only reversed a large proportion of 0g-induced effects in Pthrp+/+ TOs but maintained viability over 6-week exposure to microgravity. Our results confirm PTHrP efficacy as an anabolic agent to prevent microgravity-induced cell death in TOs.

Establishment of 3D culture and induction of osteogenic differentiation of pre-osteoblasts using wet-collected aligned scaffolds

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Ding, Huifen [Hubei-MOSTKLOS & KLOBM, School and Hospital of Stomatology, Wuhan University, Wuhan 430079 (China); Chongqing Affiliated Hospital of Stomatology, Chongqing University of Medical Sciences, Chongqing 400015 (China); Zhong, Junwen [Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Xu, Fei; Song, Fangfang; Yin, Miao; Wu, Yanru; Hu, Qiyi [Hubei-MOSTKLOS & KLOBM, School and Hospital of Stomatology, Wuhan University, Wuhan 430079 (China); Wang, Jiawei, E-mail: wangjwei@hotmail.com [Hubei-MOSTKLOS & KLOBM, School and Hospital of Stomatology, Wuhan University, Wuhan 430079 (China)

2017-02-01

Aligned fibrous scaffolds have attracted much interest in bone tissue engineering, because they are supposed to induce osteogenic differentiation. For the first time, aligned silk fibroin nanofibres were loosely packed using a novel wet-collection electrospinning method. Moreover, three-dimensional (3D) culture of MC3T3-E1 pre-osteoblasts was established on these fibrous scaffolds. Physicochemical properties of the scaffolds and the behaviour of MC3T3-E1 pre-osteoblasts on the scaffolds were analysed and compared with scaffolds obtained using traditional method. Ethanol bath improved the uniformity and alignment of the fibres and increased the thickness and porosity of the scaffolds. Structures of the fibres were well maintained after immediate crosslinking in ethanol. Cells on the wet-collected scaffolds exhibited more ordered arrangement and elongated morphology as well as faster and deeper infiltration. The ordered infiltration resulted in the establishment of the 3D culture of cells, promoting proliferation and osteogenic differentiation of the pre-osteoblasts. Thus, the wet-collected aligned scaffolds with improved topographical and physicochemical properties presents significant potential application in bone regeneration. - Highlights: • Aligned silk fibroin nanofibres were loosely packed using a novel wet-collection electrospinning method. • Structural properties of the aligned nanofibres were improved. • Three-dimensional culture of MC3T3-E1 pre-osteoblasts was established. • The arrangement, morphology, infiltration, proliferation and osteogenic differentiation of cells were enhanced.

Functional expression of 5-HT{sub 2A} receptor in osteoblastic MC3T3-E1 cells

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Hirai, Takao; Kaneshige, Kota; Kurosaki, Teruko [Department of Molecular Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 1 Gakuen-cho, Fukuyama, Hiroshima 729-0292 (Japan); Nishio, Hiroaki, E-mail: nishio@fupharm.fukuyama-u.ac.jp [Department of Molecular Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, 1 Gakuen-cho, Fukuyama, Hiroshima 729-0292 (Japan)

2010-05-28

In the previous study, we reported the gene expression for proteins related to the function of 5-hydroxytryptamine (5-HT, serotonin) and elucidated the expression patterns of 5-HT{sub 2} receptor subtypes in mouse osteoblasts. In the present study, we evaluated the possible involvement of 5-HT receptor subtypes and its inactivation system in MC3T3-E1 cells, an osteoblast cell line. DOI, a 5-HT{sub 2A} and 5-HT{sub 2C} receptor selective agonist, as well as 5-HT concentration-dependently increased proliferative activities of MC3T3-E1 cells in their premature period. This effect of 5-HT on cell proliferation were inhibited by ketanserin, a 5-HT{sub 2A} receptor specific antagonist. Moreover, both DOI-induced cell proliferation and phosphorylation of ERK1 and 2 proteins were inhibited by PD98059 and U0126, selective inhibitors of MEK in a concentration-dependent manner. Furthermore, treatment with fluoxetine, a 5-HT specific re-uptake inhibitor which inactivate the function of extracellular 5-HT, significantly increased the proliferative activities of MC3T3-E1 cells in a concentration-dependent manner. Our data indicate that 5-HT fill the role for proliferation of osteoblast cells in their premature period. Notably, 5-HT{sub 2A} receptor may be functionally expressed to regulate mechanisms underlying osteoblast cell proliferation, at least in part, through activation of ERK/MAPK pathways in MC3T3-E1 cells.

Effect of dual delivery of antibiotics (vancomycin and cefazolin) and BMP-7 from chitosan microparticles on Staphylococcus epidermidis and pre-osteoblasts in vitro

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Mantripragada, Venkata P. [Biomedical Engineering Program, The University of Toledo, Toledo, OH 43614-5807 (United States); Jayasuriya, Ambalangodage C., E-mail: a.jayasuriya@utoledo.edu [Biomedical Engineering Program, The University of Toledo, Toledo, OH 43614-5807 (United States); Department of Orthopaedic Surgery, The University of Toledo, Toledo, OH 43614-5807 (United States)

2016-10-01

The main aims of this manuscript are to: i) determine the effect of commonly used antibiotics to treat osteoarticular infections on osteoblast viability, ii) study the dual release of the growth factor (BMP-7) and antibiotics (vancomycin and cefazolin) from chitosan microparticles iii) demonstrate the bioactivity of the antibiotics released in vitro on Staphylococcus epidermidis. The novelty of this work is dual delivery of growth factor and antibiotic from the chitosan microparticles in a controlled manner without affecting their bioactivity. Cefazolin and vancomycin have different therapeutic concentrations for their action in vivo and therefore, two different concentrations of the drugs were used. Osteoblast cytotoxicity test concluded that cefazolin concentrations of 50 and 100 μg/ml were found to have positive influence on osteoblast proliferation. A significant increase in osteoblast proliferation was observed in the presence of cefazolin and BMP-7 in comparison with BMP-7 alone group; indicating cefazolin might play a role in osteoblast proliferation. On the other hand, vancomycin concentration of 1000 μg/ml was found to significantly reduce (p < 0.01) osteoblast proliferation in comparison with controls. The microbial study indicated that cefazolin at a minimum concentration of 21.5 μg/ml could inhibit ~ 85% growth of S. epidermidis, whereas vancomycin at a concentration of 30 μg/ml was found to inhibit ~ 80% bacterial growth. - Highlights: • Bacterial infections involve the inflammatory destruction of joint and bone. • Vancomycin and cefazolin half-life is limited to a few hours. • Dual delivery of growth factor and antibiotic from the chitosan microparticles. • Bioactivity of antibiotics released by the microparticles was protected.

Effect of dual delivery of antibiotics (vancomycin and cefazolin) and BMP-7 from chitosan microparticles on Staphylococcus epidermidis and pre-osteoblasts in vitro

International Nuclear Information System (INIS)

Mantripragada, Venkata P.; Jayasuriya, Ambalangodage C.

2016-01-01

The main aims of this manuscript are to: i) determine the effect of commonly used antibiotics to treat osteoarticular infections on osteoblast viability, ii) study the dual release of the growth factor (BMP-7) and antibiotics (vancomycin and cefazolin) from chitosan microparticles iii) demonstrate the bioactivity of the antibiotics released in vitro on Staphylococcus epidermidis. The novelty of this work is dual delivery of growth factor and antibiotic from the chitosan microparticles in a controlled manner without affecting their bioactivity. Cefazolin and vancomycin have different therapeutic concentrations for their action in vivo and therefore, two different concentrations of the drugs were used. Osteoblast cytotoxicity test concluded that cefazolin concentrations of 50 and 100 μg/ml were found to have positive influence on osteoblast proliferation. A significant increase in osteoblast proliferation was observed in the presence of cefazolin and BMP-7 in comparison with BMP-7 alone group; indicating cefazolin might play a role in osteoblast proliferation. On the other hand, vancomycin concentration of 1000 μg/ml was found to significantly reduce (p < 0.01) osteoblast proliferation in comparison with controls. The microbial study indicated that cefazolin at a minimum concentration of 21.5 μg/ml could inhibit ~ 85% growth of S. epidermidis, whereas vancomycin at a concentration of 30 μg/ml was found to inhibit ~ 80% bacterial growth. - Highlights: • Bacterial infections involve the inflammatory destruction of joint and bone. • Vancomycin and cefazolin half-life is limited to a few hours. • Dual delivery of growth factor and antibiotic from the chitosan microparticles. • Bioactivity of antibiotics released by the microparticles was protected.

Temporal Profiling and Pulsed SILAC Labeling Identify Novel Secreted Proteins During Ex Vivo Osteoblast Differentiation of Human Stromal Stem Cells*

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Kristensen, Lars P.; Chen, Li; Nielsen, Maria Overbeck; Qanie, Diyako W.; Kratchmarova, Irina; Kassem, Moustapha; Andersen, Jens S.

2012-01-01

It is well established that bone forming cells (osteoblasts) secrete proteins with autocrine, paracrine, and endocrine function. However, the identity and functional role for the majority of these secreted and differentially expressed proteins during the osteoblast (OB) differentiation process, is not fully established. To address these questions, we quantified the temporal dynamics of the human stromal (mesenchymal, skeletal) stem cell (hMSC) secretome during ex vivo OB differentiation using stable isotope labeling by amino acids in cell culture (SILAC). In addition, we employed pulsed SILAC labeling to distinguish genuine secreted proteins from intracellular contaminants. We identified 466 potentially secreted proteins that were quantified at 5 time-points during 14-days ex vivo OB differentiation including 41 proteins known to be involved in OB functions. Among these, 315 proteins exhibited more than 2-fold up or down-regulation. The pulsed SILAC method revealed a strong correlation between the fraction of isotope labeling and the subset of proteins known to be secreted and involved in OB differentiation. We verified SILAC data using qRT-PCR analysis of 9 identified potential novel regulators of OB differentiation. Furthermore, we studied the biological effects of one of these proteins, the hormone stanniocalcin 2 (STC2) and demonstrated its autocrine effects in enhancing osteoblastic differentiation of hMSC. In conclusion, combining complete and pulsed SILAC labeling facilitated the identification of novel factors produced by hMSC with potential role in OB differentiation. Our study demonstrates that the secretome of osteoblastic cells is more complex than previously reported and supports the emerging evidence that osteoblastic cells secrete proteins with endocrine functions and regulate cellular processes beyond bone formation. PMID:22801418

Effect of soybean extract after tooth extraction on osteoblast numbers

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Rosa Sharon Suhono

2011-06-01

Full Text Available Background: Many researches were done to find natural materials that may increase and promote bone healing processes after trauma and surgery. One of natural material that had been studied was soybean extract which contains phytoestrogen, a non-steroidal compounds found in plants that may binds to estrogen receptors and have estrogen-like activity. Purpose: The aim of this study was to investigate the effect of soybean extract feeding on the number of osteoblast cells in alveolar bone socket after mandibular tooth extraction. Methods: This study was studied on male Rattus norvegicus strain Wistar. Seventeen rats divided into three groups were used in this study. Group 1 fed with carboxy methyl cellulose (CMC solution 0,2% for seven days, and the left mandibular central incisivus was extracted; group 2 fed with soybean extract for seven days and the left mandibular central incisives was extracted; group 3 received the left mandibular central incisives extraction followed by soybean extract feeding for seven days after the extraction. All groups were sacrificed on the seventh day post-extraction, and the alveolar bone sockets were taken for histopathological observation. The tissues were processed and stained using hematoxylin and eosin to identify the amount of osteoblast cells. The number of osteoblast cells was counted using an Image Tool program. The data was analyzed statistically using the One-Way ANOVA test. Results: Significant differences were found on the number of osteoblast cells in alveolar bone after tooth extraction between groups. Group 2 (fed with soybean extract is higher than group 1 (fed with CMC and group 3 (fed with soybean extract after extraction. Conclusion: Soybean extract feeding that given for seven days pre-tooth extraction can increase the number of osteoblast cells compared with the group that were not given soybean extract feeding and also with the group that were given soybean extract feeding for seven days post

In Vitro Proliferation and Anti-Apoptosis of the Papain-Generated Casein and Soy Protein Hydrolysates towards Osteoblastic Cells (hFOB1.19).

Science.gov (United States)

Pan, Xiao-Wen; Zhao, Xin-Huai

2015-06-17

Casein and soy protein were digested by papain to three degrees of hydrolysis (DH) 7.3%-13.3%, to obtain respective six casein and soy protein hydrolysates, aiming to clarify their in vitro proliferation and anti-apoptosis towards a human osteoblastic cell line (hFOB1.19 cells). Six casein and soy protein hydrolysates at five levels (0.01-0.2 mg/mL) mostly showed proliferation as positive 17β-estradiol did, because they conferred the osteoblasts with cell viability of 100%-114% and 104%-123%, respectively. The hydrolysates of higher DH values had stronger proliferation. Casein and soy protein hydrolysates of the highest DH values altered cell cycle progression, and enhanced cell proportion of S-phase from 50.5% to 56.5% and 60.5%. The two also antagonized etoposide- and NaF-induced osteoblast apoptosis. In apoptotic prevention, apoptotic cells were decreased from 31.6% to 22.6% and 15.6% (etoposide treatment), or from 19.5% to 17.7% and 12.4% (NaF treatment), respectively. In apoptotic reversal, soy protein hydrolysate decreased apoptotic cells from 13.3% to 11.7% (etoposide treatment), or from 14.5% to 11.0% (NaF treatment), but casein hydrolysate showed no reversal effect. It is concluded that the hydrolysates of two kinds had estradiol-like action on the osteoblasts, and soy protein hydrolysates had stronger proliferation and anti-apoptosis on the osteoblasts than casein hydrolysates.

Surface modification of TiO{sub 2} nanotubes with osteogenic growth peptide to enhance osteoblast differentiation

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Lai, Min, E-mail: minlai@jsnu.edu.cn [School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China); Jin, Ziyang [School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116 (China); Su, Zhiguo [Department of Pharmacy, The Affiliated hospital of Qingdao University, Qingdao, Shandong 266555 (China)