scholarly journals Decreased C-Src Expression Enhances Osteoblast Differentiation and Bone Formation

2000 ◽  
Vol 151 (2) ◽  
pp. 311-320 ◽  
Author(s):  
Marilena Marzia ◽  
Natalie A. Sims ◽  
Susanne Voit ◽  
Silvia Migliaccio ◽  
Anna Taranta ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Matrix Protein ◽  
Bone Matrix ◽  
Osteogenic Cells ◽  
Alp Activity ◽  
Pthrp Receptor ◽  
Bone Matrix Protein

c-src deletion in mice leads to osteopetrosis as a result of reduced bone resorption due to an alteration of the osteoclast. We report that deletion/reduction of Src expression enhances osteoblast differentiation and bone formation, contributing to the increase in bone mass. Bone histomorphometry showed that bone formation was increased in Src null compared with wild-type mice. In vitro, alkaline phosphatase (ALP) activity and nodule mineralization were increased in primary calvarial cells and in SV40-immortalized osteoblasts from Src−/− relative to Src+/+ mice. Src-antisense oligodeoxynucleotides (AS-src) reduced Src levels by ∼60% and caused a similar increase in ALP activity and nodule mineralization in primary osteoblasts in vitro. Reduction in cell proliferation was observed in primary and immortalized Src−/− osteoblasts and in normal osteoblasts incubated with the AS-src. Semiquantitative reverse transcriptase-PCR revealed upregulation of ALP, Osf2/Cbfa1 transcription factor, PTH/PTHrP receptor, osteocalcin, and pro-alpha 2(I) collagen in Src-deficient osteoblasts. The expression of the bone matrix protein osteopontin remained unchanged. Based on these results, we conclude that the reduction of Src expression not only inhibits bone resorption, but also stimulates osteoblast differentiation and bone formation, suggesting that the osteogenic cells may contribute to the development of the osteopetrotic phenotype in Src-deficient mice.

scholarly journals Regulation of Proliferation, Differentiation and Functions of Osteoblasts by Runx2

2019 ◽  
Vol 20 (7) ◽  
pp. 1694 ◽  
Author(s):  
Toshihisa Komori
Keyword(s):  
Osteoblast Differentiation ◽  
Matrix Protein ◽  
Gene Dosage ◽  
Bone Matrix ◽  
Mesenchymal Cells ◽  
Heterozygous Mutation ◽  
Chondrocyte Maturation ◽  
Osteoblast Progenitors

Runx2 is essential for osteoblast differentiation and chondrocyte maturation. During osteoblast differentiation, Runx2 is weakly expressed in uncommitted mesenchymal cells, and its expression is upregulated in preosteoblasts, reaches the maximal level in immature osteoblasts, and is down-regulated in mature osteoblasts. Runx2 enhances the proliferation of osteoblast progenitors by directly regulating Fgfr2 and Fgfr3. Runx2 enhances the proliferation of suture mesenchymal cells and induces their commitment into osteoblast lineage cells through the direct regulation of hedgehog (Ihh, Gli1, and Ptch1), Fgf (Fgfr2 and Fgfr3), Wnt (Tcf7, Wnt10b, and Wnt1), and Pthlh (Pthr1) signaling pathway genes, and Dlx5. Runx2 heterozygous mutation causes open fontanelle and sutures because more than half of the Runx2 gene dosage is required for the induction of these genes in suture mesenchymal cells. Runx2 regulates the proliferation of osteoblast progenitors and their differentiation into osteoblasts via reciprocal regulation with hedgehog, Fgf, Wnt, and Pthlh signaling molecules, and transcription factors, including Dlx5 and Sp7. Runx2 induces the expression of major bone matrix protein genes, including Col1a1, Spp1, Ibsp, Bglap2, and Fn1, in vitro. However, the functions of Runx2 in differentiated osteoblasts in the expression of these genes in vivo require further investigation.

scholarly journals Freeze-Dried Secretome (Lyosecretome) from Mesenchymal Stem/Stromal Cells Promotes the Osteoinductive and Osteoconductive Properties of Titanium Cages

2021 ◽  
Vol 22 (16) ◽  
pp. 8445
Author(s):  
Elia Bari ◽  
Fulvio Tartara ◽  
Fabio Cofano ◽  
Giuseppe di Perna ◽  
Diego Garbossa ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Bone Matrix ◽  
In Vitro Tests ◽  
Alizarin Red ◽  
Cellular Processes ◽  
Freeze Dried ◽  
Good Biocompatibility ◽  
Titanium Cages ◽  
Bone Matrix Protein

Titanium is one of the most frequently used materials in bone regeneration due to its good biocompatibility, excellent mechanical properties, and great osteogenic performance. However, osseointegration with host tissue is often not definite, which may cause implant failure at times. The present study investigates the capacity of the mesenchymal stem cell (MSC)-secretome, formulated as a ready-to-use and freeze-dried medicinal product (the Lyosecretome), to promote the osteoinductive and osteoconductive properties of titanium cages. In vitro tests were conducted using adipose tissue-derived MSCs seeded on titanium cages with or without Lyosecretome. After 14 days, in the presence of Lyosecretome, significant cell proliferation improvement was observed. Scanning electron microscopy revealed the cytocompatibility of titanium cages: the seeded MSCs showed a spread morphology and an initial formation of filopodia. After 7 days, in the presence of Lyosecretome, more frequent and complex cellular processes forming bridges across the porous surface of the scaffold were revealed. Also, after 14 and 28 days of culturing in osteogenic medium, the amount of mineralized matrix detected by alizarin red was significantly higher when Lyosecretome was used. Finally, improved osteogenesis with Lyosecretome was confirmed by confocal analysis after 28 and 56 days of treatment, and demonstrating the production by osteoblast-differentiated MSCs of osteocalcin, a specific bone matrix protein.

scholarly journals Osteoblastic Responses to TGF-β during Bone Remodeling

1998 ◽  
Vol 9 (7) ◽  
pp. 1903-1918 ◽  
Author(s):  
Adrian Erlebacher ◽  
Ellen H. Filvaroff ◽  
Jian-Qin Ye ◽  
Rik Derynck
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Transgenic Mice ◽  
Bone Remodeling ◽  
Osteoblast Differentiation ◽  
Bone Matrix ◽  
Physiological Role ◽  
Dominant Negative ◽  
Central Component ◽  
Physiological Regulator

Bone remodeling depends on the spatial and temporal coupling of bone formation by osteoblasts and bone resorption by osteoclasts; however, the molecular basis of these inductive interactions is unknown. We have previously shown that osteoblastic overexpression of TGF-β2 in transgenic mice deregulates bone remodeling and leads to an age-dependent loss of bone mass that resembles high-turnover osteoporosis in humans. This phenotype implicates TGF-β2 as a physiological regulator of bone remodeling and raises the question of how this single secreted factor regulates the functions of osteoblasts and osteoclasts and coordinates their opposing activities in vivo. To gain insight into the physiological role of TGF-β in bone remodeling, we have now characterized the responses of osteoblasts to TGF-β in these transgenic mice. We took advantage of the ability of alendronate to specifically inhibit bone resorption, the lack of osteoclast activity in c-fos −/− mice, and a new transgenic mouse line that expresses a dominant-negative form of the type II TGF-β receptor in osteoblasts. Our results show that TGF-β directly increases the steady-state rate of osteoblastic differentiation from osteoprogenitor cell to terminally differentiated osteocyte and thereby increases the final density of osteocytes embedded within bone matrix. Mice overexpressing TGF-β2 also have increased rates of bone matrix formation; however, this activity does not result from a direct effect of TGF-β on osteoblasts, but is more likely a homeostatic response to the increase in bone resorption caused by TGF-β. Lastly, we find that osteoclastic activity contributes to the TGF-β–induced increase in osteoblast differentiation at sites of bone resorption. These results suggest that TGF-β is a physiological regulator of osteoblast differentiation and acts as a central component of the coupling of bone formation to resorption during bone remodeling.

scholarly journals Aesculetin Promotes Osteoblastogenic Bone Formation Through Enhancing Osteoblast Differentiation and Mineralization

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 350-350
Author(s):  
WooJin Na ◽  
Young-Hee Kang
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Osteoblastic Differentiation ◽  
Alizarin Red S ◽  
Type I ◽  
Mineral Density ◽  
Alizarin Red ◽  
Alp Activity ◽  
Cellular Expression

Abstract Objectives Osteoporosis is a common chronic disease elicited by imbalance between osteoblastic bone formation and osteoclastic bone resorption. Marked increase in bone resorption leads to the aberrant fall in bone mineral density. With increasing age, there is also a significant reduction in bone formation. Aesculetin, a derivative of coumarin, possesses anti-inflammatory and antioxidant effects. The purpose of this study was to identify that aesculetin accelerated bone formation through increased osteoblastic differentiation and mineralization. Methods MC3T3-E1 cells were cultured with 1–10 μM aesculetin in α-MEM supplemented with 10 mM β-glycerophosphate, 50 μg/ml ascorbic acid and 10 μM dexamethasone for up to 21 days. Alkaline phosphatase (ALP) activity and staining, Alizarin red S staining, and Western blotting for induction of target proteins were conducted for the measurement of osteoblastic differentiation and mineralization. Results Aesculetin further enhanced the ALP activity of differentiated MC3T3-E1 cells, showing that aesculetin stimulated the osteoblast differentiation. Alizarin red S staining revealed that calcium deposits highly increased in 1–10 μM aesculetin-treated osteoblasts. In addition, aesculetin further increased cellular expression of the bone-forming markers of bone morphogenetic protein-2, osteopontin and collagen type I in osteoblasts. Conclusions Aesculetin was effective in enhancing osteoblast differentiation and bone mineralization for bone formation, indicating that this compound may be a potential agent for the treatment of osteoporosis. Funding Sources This work was supported by the BK21 FOUR(Fostering Outstanding Universities for Research, 4220200913807) funded by the National Research Foundation of Korea (NRF).

Alterations of Bone Matrix Protein mRNA Expression in Rat Aorta In Vitro

1995 ◽  
Vol 15 (9) ◽  
pp. 1474-1480 ◽  
Author(s):  
Hiroyuki Hao ◽  
Seiichi Hirota ◽  
Yoshitane Tsukamoto ◽  
Masami Imakita ◽  
Hatsue Ishibashi-Ueda ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Matrix Protein ◽  
Bone Matrix ◽  
Rat Aorta ◽  
Bone Matrix Protein

scholarly journals A novel gelatin/chitooligosaccharide/demineralized bone matrix composite scaffold and periosteum-derived mesenchymal stem cells for bone tissue engineering

2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Thakoon Thitiset ◽  
Siriporn Damrongsakkul ◽  
Supansa Yodmuang ◽  
Wilairat Leeanansaksiri ◽  
Jirun Apinun ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Bone Formation ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Alp Activity

Abstract Background A novel biodegradable scaffold including gelatin (G), chitooligosaccharide (COS), and demineralized bone matrix (DBM) could play a significant part in bone tissue engineering. The present study aimed to investigate the biological characteristics of composite scaffolds in combination of G, COS, and DBM for in vitro cell culture and in vivo animal bioassays. Methods Three-dimensional scaffolds from the mixture of G, COS, and DBM were fabricated into 3 groups, namely, G, GC, and GCD using a lyophilization technique. The scaffolds were cultured with mesenchymal stem cells (MSCs) for 4 weeks to determine biological responses such as cell attachment and cell proliferation, alkaline phosphatase (ALP) activity, calcium deposition, cell morphology, and cell surface elemental composition. For the in vivo bioassay, G, GC, and GCD, acellular scaffolds were implanted subcutaneously in 8-week-old male Wistar rats for 4 weeks and 8 weeks. The explants were assessed for new bone formation using hematoxylin and eosin (H&E) staining and von Kossa staining. Results The MSCs could attach and proliferate on all three groups of scaffolds. Interestingly, the ALP activity of MSCs reached the greatest value on day 7 after cultured on the scaffolds, whereas the calcium assay displayed the highest level of calcium in MSCs on day 28. Furthermore, weight percentages of calcium and phosphorus on the surface of MSCs after cultivation on the GCD scaffolds increased when compared to those on other scaffolds. The scanning electron microscopy images showed that MSCs attached and proliferated on the scaffold surface thoroughly over the cultivation time. Mineral crystal aggregation was evident in GC and greatly in GCD scaffolds. H&E staining illustrated that G, GC, and GCD scaffolds displayed osteoid after 4 weeks of implantation and von Kossa staining confirmed the mineralization at 8 weeks in G, GC, and GCD scaffolds. Conclusion The MSCs cultured in GCD scaffolds revealed greater osteogenic differentiation than those cultured in G and GC scaffolds. Additionally, the G, GC, and GCD scaffolds could promote in vivo ectopic bone formation in rat model. The GCD scaffolds exhibited maximum osteoinductive capability compared with others and may be potentially used for bone regeneration.

scholarly journals Lumican Inhibits Osteoclastogenesis and Bone Resorption by Suppressing Akt Activity

2021 ◽  
Vol 22 (9) ◽  
pp. 4717
Author(s):  
Jin-Young Lee ◽  
Da-Ae Kim ◽  
Eun-Young Kim ◽  
Eun-Ju Chang ◽  
So-Jeong Park ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Map Kinases ◽  
Osteoclast Differentiation ◽  
Dependent Manner ◽  
Dual Action ◽  
Dose Dependent ◽  
Resorptive Activity

Lumican, a ubiquitously expressed small leucine-rich proteoglycan, has been utilized in diverse biological functions. Recent experiments demonstrated that lumican stimulates preosteoblast viability and differentiation, leading to bone formation. To further understand the role of lumican in bone metabolism, we investigated its effects on osteoclast biology. Lumican inhibited both osteoclast differentiation and in vitro bone resorption in a dose-dependent manner. Consistent with this, lumican markedly decreased the expression of osteoclastogenesis markers. Moreover, the migration and fusion of preosteoclasts and the resorptive activity per osteoclast were significantly reduced in the presence of lumican, indicating that this protein affects most stages of osteoclastogenesis. Among RANKL-dependent pathways, lumican inhibited Akt but not MAP kinases such as JNK, p38, and ERK. Importantly, co-treatment with an Akt activator almost completely reversed the effect of lumican on osteoclast differentiation. Taken together, our findings revealed that lumican inhibits osteoclastogenesis by suppressing Akt activity. Thus, lumican plays an osteoprotective role by simultaneously increasing bone formation and decreasing bone resorption, suggesting that it represents a dual-action therapeutic target for osteoporosis.

scholarly journals The Bromodomain Inhibitor N-Methyl pyrrolidone Prevents Osteoporosis and BMP-Triggered Sclerostin Expression in Osteocytes

2018 ◽  
Vol 19 (11) ◽  
pp. 3332 ◽  
Author(s):  
Barbara Siegenthaler ◽  
Chafik Ghayor ◽  
Bebeka Gjoksi-Cosandey ◽  
Nisarat Ruangsawasdi ◽  
Franz Weber
Keyword(s):  
Bone Resorption ◽  
Bone Formation ◽  
Osteoporosis Treatment ◽  
Estrogen Deficiency ◽  
Bone Morphogenetic Protein 2 ◽  
Protein Levels ◽  
Osteoporosis Management ◽  
Promising Target

(1) Background: In an adult skeleton, bone is constantly renewed in a cycle of bone resorption, followed by bone formation. This coupling process, called bone remodeling, adjusts the quality and quantity of bone to the local needs. It is generally accepted that osteoporosis develops when bone resorption surpasses bone formation. Osteoclasts and osteoblasts, bone resorbing and bone forming cells respectively, are the major target in osteoporosis treatment. Inside bone and forming a complex network, the third and most abundant cells, the osteocytes, have long remained a mystery. Osteocytes are responsible for mechano-sensation and -transduction. Increased expression of the osteocyte-derived bone inhibitor sclerostin has been linked to estrogen deficiency-induced osteoporosis and is therefore a promising target for osteoporosis management. (2) Methods: Recently we showed in vitro and in vivo that NMP (N-Methyl-2-pyrrolidone) is a bioactive drug enhancing the BMP-2 (Bone Morphogenetic Protein 2) induced effect on bone formation while blocking bone resorption. Here we tested the effect of NMP on the expression of osteocyte-derived sclerostin. (3) Results: We found that NMP significantly decreased sclerostin mRNA and protein levels. In an animal model of osteoporosis, NMP prevented the estrogen deficiency-induced increased expression of sclerostin. (4) Conclusions: These results support the potential of NMP as a novel therapeutic compound for osteoporosis management, since it preserves bone by a direct interference with osteoblasts and osteoclasts and an indirect one via a decrease in sclerostin expression by osteocytes.

scholarly journals Effects of Farnesyl Pyrophosphate Accumulation on Calvarial Osteoblast Differentiation

Endocrinology ◽  
2011 ◽  
Vol 152 (8) ◽  
pp. 3113-3122 ◽  
Author(s):  
Megan M. Weivoda ◽  
Raymond J. Hohl
Keyword(s):  
Bone Formation ◽  
Osteoblast Differentiation ◽  
Biosynthetic Pathway ◽  
Squalene Synthase ◽  
Farnesyl Pyrophosphate ◽  
Matrix Mineralization ◽  
Lower Serum Cholesterol ◽  
Calvarial Osteoblast ◽  
Isoprenoid Biosynthetic Pathway

Statins, drugs commonly used to lower serum cholesterol, have been shown to stimulate osteoblast differentiation and bone formation. Statins inhibit 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A reductase (HMGCR), the first step of the isoprenoid biosynthetic pathway, leading to the depletion of the isoprenoids farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). The effects of statins on bone have previously been attributed to the depletion of GGPP, because the addition of exogenous GGPP prevented statin-stimulated osteoblast differentiation in vitro. However, in a recent report, we demonstrated that the specific depletion of GGPP did not stimulate but, in fact, inhibited osteoblast differentiation. This led us to hypothesize that isoprenoids upstream of GGPP play a role in the regulation of osteoblast differentiation. We demonstrate here that the expression of HMGCR and FPP synthase decreased during primary calvarial osteoblast differentiation, correlating with decreased FPP and GGPP levels during differentiation. Zaragozic acid (ZGA) inhibits the isoprenoid biosynthetic pathway enzyme squalene synthase, leading to an accumulation of the squalene synthase substrate FPP. ZGA treatment of calvarial osteoblasts led to a significant increase in intracellular FPP and resulted in inhibition of osteoblast differentiation as measured by osteoblastic gene expression, alkaline phosphatase activity, and matrix mineralization. Simultaneous HMGCR inhibition prevented the accumulation of FPP and restored osteoblast differentiation. In contrast, specifically inhibiting GGPPS to lower the ZGA-induced increase in GGPP did not restore osteoblast differentiation. The specificity of HMGCR inhibition to restore osteoblast differentiation of ZGA-treated cultures through the reduction in isoprenoid accumulation was confirmed with the addition of exogenous mevalonate. Similar to ZGA treatment, exogenous FPP inhibited the mineralization of primary calvarial osteoblasts. Interestingly, the effects of FPP accumulation on osteoblasts were found to be independent of protein farnesylation. Our findings are the first to demonstrate that the accumulation of FPP impairs osteoblast differentiation and suggests that the depletion of this isoprenoid may be necessary for normal and statin-induced bone formation.

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