scholarly journals Zfp521 antagonizes Runx2, delays osteoblast differentiation in vitro, and promotes bone formation in vivo

Bone ◽  
2009 ◽  
Vol 44 (4) ◽  
pp. 528-536 ◽  
Author(s):  
Meilin Wu ◽  
Eric Hesse ◽  
Frederic Morvan ◽  
Jian-Ping Zhang ◽  
Diego Correa ◽  
...  
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation

scholarly journals Hedgehog Signaling Inhibition by Smoothened Antagonist BMS-833923 Reduces Osteoblast Differentiation and Ectopic Bone Formation of Human Skeletal (Mesenchymal) Stem Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Nihal AlMuraikhi ◽  
Nuha Almasoud ◽  
Sarah Binhamdan ◽  
Ghaydaa Younis ◽  
Dalia Ali ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Global Gene Expression ◽  
Ectopic Bone Formation ◽  
Ectopic Bone ◽  
In Vitro Mineralization ◽  
Global Gene Expression Profiling

Background. Hedgehog (Hh) signaling is essential for osteoblast differentiation of mesenchymal progenitors during endochondral bone formation. However, the critical role of Hh signaling during adult bone remodeling remains to be elucidated. Methods. A Smoothened (SMO) antagonist/Hedgehog inhibitor, BMS-833923, identified during a functional screening of a stem cell signaling small molecule library, was investigated for its effects on the osteoblast differentiation of human skeletal (mesenchymal) stem cells (hMSC). Alkaline phosphatase (ALP) activity and Alizarin red staining were employed as markers for osteoblast differentiation and in vitro mineralization capacity, respectively. Global gene expression profiling was performed using the Agilent® microarray platform. Effects on in vivo ectopic bone formation were assessed by implanting hMSC mixed with hydroxyapatite-tricalcium phosphate granules subcutaneously in 8-week-old female nude mice, and the amount of bone formed was assessed using quantitative histology. Results. BMS-833923, a SMO antagonist/Hedgehog inhibitor, exhibited significant inhibitory effects on osteoblast differentiation of hMSCs reflected by decreased ALP activity, in vitro mineralization, and downregulation of osteoblast-related gene expression. Similarly, we observed decreased in vivo ectopic bone formation. Global gene expression profiling of BMS-833923-treated compared to vehicle-treated control cells, identified 348 upregulated and 540 downregulated genes with significant effects on multiple signaling pathways, including GPCR, endochondral ossification, RANK-RANKL, insulin, TNF alpha, IL6, and inflammatory response. Further bioinformatic analysis employing Ingenuity Pathway Analysis revealed significant enrichment in BMS-833923-treated cells for a number of functional categories and networks involved in connective and skeletal tissue development and disorders, e.g., NFκB and STAT signaling. Conclusions. We identified SMO/Hedgehog antagonist (BMS-833923) as a powerful inhibitor of osteoblastic differentiation of hMSC that may be useful as a therapeutic option for treating conditions associated with high heterotopic bone formation and mineralization.

ONO-1301 Enhances in vitro Osteoblast Differentiation and in vivo Bone Formation Induced by Bone Morphogenetic Protein

Spine ◽  
2018 ◽  
Vol 43 (11) ◽  
pp. E616-E624 ◽  
Author(s):  
Sadaaki Kanayama ◽  
Takashi Kaito ◽  
Kazuma Kitaguchi ◽  
Hiroyuki Ishiguro ◽  
Kunihiko Hashimoto ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Morphogenetic Protein ◽  
Osteoblast Differentiation ◽  
Morphogenetic Protein ◽  
In Vivo Bone Formation

scholarly journals Porcine Collagen–Bone Composite Induced Osteoblast Differentiation and Bone Regeneration In Vitro and In Vivo

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 93 ◽  
Author(s):  
Eisner Salamanca ◽  
Chia Chen Hsu ◽  
Wan Ling Yao ◽  
Cheuk Sing Choy ◽  
Yu Hwa Pan ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Regeneration ◽  
Osteoblast Differentiation ◽  
Critical Size ◽  
Guided Bone Regeneration ◽  
Autogenous Bone ◽  
Critical Size Defects ◽  
Bone Formation Markers

Due to autogenous bone limitations, some substitute bone grafts were developed. Collagenated porcine graft (CPG) is able to regenerate new bone, although the number of studies is insufficient, highlighting the need for future studies to better understand the biomaterial. In order to understand better CPG′s possible dental guided bone regeneration indications, the aim of this work was to determine CPG′s biological capacity to induce osteoblast differentiation in vitro and guided bone regeneration in vivo, whilst being compared with commercial hydroxyapatite and beta tricalcium phosphate (HA/β-TCP) and porcine graft alone. Cell cytotoxicity (WST-1), alkaline phosphatase activity (ALP), and real-time polymerase chain reaction (qPCR) were assessed in vitro. Critical size defects of New Zealand white rabbits were used for the in vivo part, with critical size defect closures and histological analyses. WST-1 and ALP indicated that CPG directly stimulated a greater proliferation and confluency of cells with osteoblastic differentiation in vitro. Gene sequencing indicated stable bone formation markers, decreased resorption makers, and bone remodeling coupling factors, making the transition from osteoclast to osteoblast expression at the end of seven days. CPG resulted in the highest new bone regeneration by osteoconduction in critical size defects of rabbit calvaria at eight weeks. Nonetheless, all biomaterials achieved nearly complete calvaria defect closure. CPG was found to be osteoconductive, like porcine graft and HA/β-TCP, but with higher new bone formation in critical size defects of rabbit calvaria at eight weeks. CPG can be used for different dental guided bone regeneration procedures; however, further studies are necessary.

scholarly journals ER stress arm XBP1s plays a pivotal role in proteasome inhibition-induced bone formation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Dan Zhang ◽  
Kim De Veirman ◽  
Rong Fan ◽  
Qiang Jian ◽  
Yuchen Zhang ◽  
...  
Keyword(s):  
Bone Formation ◽  
Er Stress ◽  
Osteogenic Differentiation ◽  
Osteoblast Differentiation ◽  
Bone Destruction ◽  
Proteasome Inhibition ◽  
Stress Signaling ◽  
Alizarin Red

Abstract Background Bone destruction is a hallmark of multiple myeloma (MM). It has been reported that proteasome inhibitors (PIs) can reduce bone resorption and increase bone formation in MM patients, but the underlying mechanisms remain unclear. Methods Mesenchymal stem cells (MSCs) were treated with various doses of PIs, and the effects of bortezomib or carfilzomib on endoplasmic reticulum (ER) stress signaling pathways were analyzed by western blotting and real-time PCR. Alizarin red S (ARS) and alkaline phosphatase (ALP) staining were used to determine the osteogenic differentiation in vitro. Specific inhibitors targeting different ER stress signaling and a Tet-on inducible overexpressing system were used to validate the roles of key ER stress components in regulating osteogenic differentiation of MSCs. Chromatin immunoprecipitation (ChIP) assay was used to evaluate transcription factor-promoter interaction. MicroCT was applied to measure the microarchitecture of bone in model mice in vivo. Results We found that both PERK-ATF4 and IRE1α-XBP1s ER stress branches are activated during PI-induced osteogenic differentiation. Inhibition of ATF4 or XBP1s signaling can significantly impair PI-induced osteogenic differentiation. Furthermore, we demonstrated that XBP1s can transcriptionally upregulate ATF4 expression and overexpressing XBP1s can induce the expression of ATF4 and other osteogenic differentiation-related genes and therefore drive osteoblast differentiation. MicroCT analysis further demonstrated that inhibition of XBP1s can strikingly abolish bortezomib-induced bone formation in mouse. Conclusions These results demonstrated that XBP1s is a master regulator of PI-induced osteoblast differentiation. Activation of IRE1α-XBP1s ER stress signaling can promote osteogenesis, thus providing a novel strategy for the treatment of myeloma bone disease.

Targeted disruption of nuclear factor erythroid-derived 2-like 1 in osteoblasts reduces bone size and bone formation in mice

2010 ◽  
Vol 40 (2) ◽  
pp. 100-110 ◽  
Author(s):  
Jonghyun Kim ◽  
Weirong Xing ◽  
Jon Wergedal ◽  
Jefferson Y. Chan ◽  
Subburaman Mohan
Keyword(s):  
Ascorbic Acid ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Quantitative Computed Tomography ◽  
Antioxidant Response ◽  
Peripheral Quantitative Computed Tomography ◽  
Bone Size ◽  
Nuclear Factor

Previous in vitro studies found that nuclear factor erythroid-derived 2-like 1 (NFE2L1) was involved in mediating ascorbic acid-induced osterix expression and osteoblast differentiation via binding to the antioxidant response element of the osterix promoter. To test the role of NFE2L1 in regulating bone formation in vivo, we disrupted NFE2L1 specifically in osteoblasts. Mice expressing Cre under the control of Col1α2 promoter were crossed with NFE2L1 loxP mice to generate Cre+ knockout (KO) and Cre− wild-type (WT) mice. Skeletal measurements by DEXA revealed 8–10% and 9–11% reduction in total body BMC and bone area in the KO mice from 3 to 8 wk of age. Peripheral quantitative computed tomography analyses found both periosteal and endosteal circumferences were reduced by 6% at the middiaphysis of the femurs from 8 wk old KO mice. Histomorphometric analyses revealed reduced bone formation was a cause for reduced bone size in the KO mice. Microcomputed tomography analysis of the metaphysis of the femur revealed that trabecular bone volume/total volume, and trabecular numbers were decreased by 30 and 53% in the NFE2L1 KO mice. Expression of osterix was decreased by 57% in the bones of NFE2L1 KO mice. In vitro nodule assay demonstrated that mineralized nodule area was reduced by 68% in the cultures of bone marrow stromal cells from NFE2L1 KO mice. Treatment of primary osteoblasts with ascorbic acid increased osterix expression by fourfold, whereas loss of NFE2L1 in osteoblasts diminished ascorbic acid stimulation of osterix expression by 50%. Our data provide the first in vivo experimental evidence that NFE2L1 produced by osteoblasts is involved in regulating osterix expression, osteoblast differentiation, and bone formation.

scholarly journals Recombinant Irisin Prevents the Reduction of Osteoblast Differentiation Induced by Stimulated Microgravity through Increasing β-Catenin Expression

2020 ◽  
Vol 21 (4) ◽  
pp. 1259 ◽  
Author(s):  
Zhihao Chen ◽  
Yan Zhang ◽  
Fan Zhao ◽  
Chong Yin ◽  
Chaofei Yang ◽  
...  
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Simulated Microgravity ◽  
Marker Gene ◽  
Calcium Deposition ◽  
Bone Homeostasis ◽  
Mice Model ◽  
Beneficial Effects

Background: Irisin, a novel exercise-induced myokine, was shown to mediate beneficial effects of exercise in osteoporosis. Microgravity is a major threat to bone homeostasis of astronauts during long-term spaceflight, which results in decreased bone formation. Methods: The hind-limb unloading mice model and a random position machine are respectively used to simulate microgravity in vivo and in vitro. Results: We demonstrate that not only are bone formation and osteoblast differentiation decreased, but the expression of fibronectin type III domain-containing 5 (Fdnc5; irisin precursor) is also downregulated under simulated microgravity. Moreover, a lower dose of recombinant irisin (r-irisin) (1 nM) promotes osteogenic marker gene (alkaline phosphatase (Alp), collagen type 1 alpha-1(ColIα1)) expressions, ALP activity, and calcium deposition in primary osteoblasts, with no significant effect on osteoblast proliferation. Furthermore, r-irisin could recover the decrease in osteoblast differentiation induced by simulated microgravity. We also find that r-irisin increases β-catenin expression and partly neutralizes the decrease in β-catenin expression induced by simulated microgravity. In addition, β-catenin overexpression could also in part attenuate osteoblast differentiation reduction induced by simulated microgravity. Conclusions: The present study is the first to show that r-irisin positively regulates osteoblast differentiation under simulated microgravity through increasing β-catenin expression, which may reveal a novel mechanism, and it provides a prevention strategy for bone loss and muscle atrophy induced by microgravity.

scholarly journals The Type 2 Cannabinoid Receptor Regulates Bone Mass and Ovariectomy-Induced Bone Loss by Affecting Osteoblast Differentiation and Bone Formation

Endocrinology ◽  
2011 ◽  
Vol 152 (6) ◽  
pp. 2141-2149 ◽  
Author(s):  
Antonia Sophocleous ◽  
Euphemie Landao-Bassonga ◽  
Robert J. van‘t Hof ◽  
Aymen I. Idris ◽  
Stuart H. Ralston
Keyword(s):  
Bone Loss ◽  
Bone Formation ◽  
Bone Mass ◽  
Osteoblast Differentiation ◽  
Cannabinoid Receptor ◽  
Nodule Formation ◽  
Wild Type

The type 2 cannabinoid receptor (CB2) has been reported to regulate bone mass and bone turnover but the mechanisms responsible are incompletely understood. In this study we investigated the role that the CB2 pathway plays in bone metabolism using a combination of genetic and pharmacological approaches. Bone mass and turnover were normal in young mice with targeted inactivation of CB2 receptor (CB2−/−), but by 12 months of age, they had developed high-turnover osteoporosis with relative uncoupling of bone resorption from bone formation. Primary osteoblasts from CB2−/− mice had a reduced capacity to form bone nodules in vitro when compared with cells from wild-type littermates and also had impaired PTH-induced alkaline phosphatase (ALP) activity. The CB2-selective agonist HU308 stimulated bone nodule formation in wild-type osteoblasts but had no effect in CB2−/− osteoblasts. Further studies in MC3T3-E1 osteoblast like cells showed that HU308 promoted cell migration and activated ERK phosphorylation, and these effects were blocked by the CB2 selective inverse agonist AM630. Finally, HU308 partially protected against ovariectomy induced bone loss in wild-type mice in vivo, primarily by stimulating bone formation, whereas no protective effects were observed in ovariectomized CB2−/− mice. These studies indicate that the CB2 regulates osteoblast differentiation in vitro and bone formation in vivo.

Neutralisation of Dkk-1 protects from systemic bone loss during inflammation and reduces sclerostin expression

2010 ◽  
Vol 69 (12) ◽  
pp. 2152-2159 ◽  
Author(s):  
Gisela Ruiz Heiland ◽  
Karin Zwerina ◽  
Wolfgang Baum ◽  
Trayana Kireva ◽  
Jörg H Distler ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Bone Architecture ◽  
Bone Homeostasis ◽  
Osteocyte Death ◽  
Primary Osteoblasts ◽  
Systemic Bone Loss

IntroductionInflammation is a major risk factor for systemic bone loss. Proinflammatory cytokines like tumour necrosis factor (TNF) affect bone homeostasis and induce bone loss. It was hypothesised that impaired bone formation is a key component in inflammatory bone loss and that Dkk-1, a Wnt antagonist, is a strong inhibitor of osteoblast-mediated bone formation.MethodsTNF transgenic (hTNFtg) mice were treated with neutralising antibodies against TNF, Dkk-1 or a combination of both agents. Systemic bone architecture was analysed by bone histomorphometry. The expression of β-catenin, osteoprotegerin and osteocalcin was analysed. In vitro, primary osteoblasts were stimulated with TNF and analysed for their metabolic activity and expression of Dkk-1 and sclerostin. Sclerostin expression and osteocyte death upon Dkk-1 blockade were analysed in vivo.ResultsNeutralisation of Dkk-1 completely protected hTNFtg mice from inflammatory bone loss by preventing TNF-mediated impaired osteoblast function and enhanced osteoclast activity. These findings were accompanied by enhanced skeletal expression of β-catenin, osteocalcin and osteoprotegerin. In vitro, TNF rapidly increased Dkk-1 expression in primary osteoblasts and effectively blocked osteoblast differentiation. Moreover, blockade of Dkk-1 not only rescued impaired osteoblastogenesis but also neutralised TNF-mediated sclerostin expression in fully differentiated osteoblasts in vitro and in vivo.ConclusionsThese findings indicate that low bone formation and expression of Dkk-1 trigger inflammatory bone loss. Dkk-1 blocks osteoblast differentiation, induces sclerostin expression and leads to osteocyte death. Inhibition of Dkk-1 may thus be considered as a potent strategy to protect bone from inflammatory damage.

scholarly journals Inhibition of BMP2-Induced Bone Formation by the p65 Subunit of NF-κB via an Interaction With Smad4

2014 ◽  
Vol 28 (9) ◽  
pp. 1460-1470 ◽  
Author(s):  
Shizu Hirata-Tsuchiya ◽  
Hidefumi Fukushima ◽  
Takenobu Katagiri ◽  
Satoshi Ohte ◽  
Masashi Shin ◽  
...  
Keyword(s):  
Dna Binding ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Bone Diseases ◽  
Bmp Signaling ◽  
Wild Type ◽  
Smad Pathway ◽  
Wild Type Mefs

Bone morphogenic proteins (BMPs) stimulate bone formation in vivo and osteoblast differentiation in vitro via a Smad signaling pathway. Recent findings revealed that the activation of nuclear factor-κB (NF-κB) inhibits BMP-induced osteoblast differentiation. Here, we show that NF-κB inhibits BMP signaling by directly targeting the Smad pathway. A selective inhibitor of the classic NF-κB pathway, BAY11–770682, enhanced BMP2-induced ectopic bone formation in vivo. In mouse embryonic fibroblasts (MEFs) prepared from mice deficient in p65, the main subunit of NF-κB, BMP2, induced osteoblastic differentiation via the Smad complex to a greater extent than that in wild-type MEFs. In p65−/− MEFs, the BMP2-activated Smad complex bound much more stably to the target element than that in wild-type MEFs without affecting the phosphorylation levels of Smad1/5/8. Overexpression of p65 inhibited BMP2 activity by decreasing the DNA binding of the Smad complex. The C-terminal region, including the TA2 domain, of p65 was essential for inhibiting the BMP-Smad pathway. The C-terminal TA2 domain of p65 associated with the MH1 domain of Smad4 but not Smad1. Taken together, our results suggest that p65 inhibits BMP signaling by blocking the DNA binding of the Smad complex via an interaction with Smad4. Our study also suggests that targeting the association between p65 and Smad4 may help to promote bone regeneration in the treatment of bone diseases.

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