-
Bone Jan 2015Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes... (Review)
Review
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.
Topics: Animals; Bone and Bones; Cell Differentiation; Humans; Intracellular Space; Osteoblasts; Signal Transduction; Stem Cells; Stromal Cells
PubMed: 25138551
DOI: 10.1016/j.bone.2014.07.028 -
Journal of Inorganic Biochemistry Jan 2018In this work we developed new antibacterial composite materials using polydopamine (PDA) to trigger the deposition of silver nanoparticles (AgNPs) onto calcium...
In this work we developed new antibacterial composite materials using polydopamine (PDA) to trigger the deposition of silver nanoparticles (AgNPs) onto calcium phosphates, namely octacalcium phosphate (OCP) and α-tricalcium phosphate (αTCP). Functionalization of OCP and αTCP with a self-polymerized polydopamine layer was obtained by soaking the calcium phosphates in dopamine solution. The PDA surface of functionalized calcium phosphates (OCPd and αTCPd) promoted the deposition of AgNPs by reducing silver ions when soaked in a silver nitrate solution. The amount of deposited AgNPs can be modulated by varying the concentration of silver nitrate solution and the type of substrate. The results of in vitro tests carried out with osteoblast-like MG63 cells indicate that the combination of AgNPs with OCP provides more biocompatible materials than those obtained using αTCP as substrate. In particular, the study of osteoblast activity and differentiation was focused on the samples OCPdAg5 (silver content=8.2wt%) and αTCPdAg5 (silver content=4.7wt%), which did not show any cytotoxicity, and compared with those obtained on pure OCP and αTCP. The results demonstrate that the AgNPs loaded materials support osteoblast viability and differentiation, whereas they significantly inhibit the growth of relevant antibiotic-resistant pathogenic bacteria.
Topics: Anti-Bacterial Agents; Biomimetics; Calcium Phosphates; Cell Line; Cell Survival; Coated Materials, Biocompatible; Humans; Indoles; Nanoparticles; Osteoblasts; Polymerase Chain Reaction; Polymers; Silver; Surface Properties
PubMed: 29049953
DOI: 10.1016/j.jinorgbio.2017.10.004 -
Molecular Medicine Reports May 2017It is widely accepted that mechanical stress is an important factor in bone associated cell differentiation, including that of mesenchymal stem cells, osteoblasts and...
It is widely accepted that mechanical stress is an important factor in bone associated cell differentiation, including that of mesenchymal stem cells, osteoblasts and osteocytes. The present study aimed to determine the effect of mechanical cyclic compressive load on osteoblast differentiation, and whether this was associated with activation of the wingless‑type (Wnt)/β-catenin signaling pathway. Using a 3D scaffold model, MC3T3‑E1 cells were exposed to cyclic compressive loading via the Flexcell‑5000C™ Compression system. Sinusoidal wave magnitudes of 0.33, 0.5 and 1 MPa were applied for 4, 6 and 8 h, at 1 Hz frequency. Expression levels of genes associated with osteoblast differentiation were enhanced following compression, including alkaline phosphatase, osteocalcin, runt‑related transcription factor 2 and osterix. Optimal compression was observed using a magnitude of 0.5 MPa for 6 h, whereas a magnitude of 1 MPa had no effect on osteoblast differentiation, and had a negative effect when applied for prolonged time periods. Compressive loading additionally enhanced the mRNA expression levels of the Wnt/β‑catenin signaling pathway component, low density lipoprotein receptor‑related protein 5, and the protein expression levels of Wnt1, disheveled segment polarity protein‑2 (DVL2) and β-catenin. By contrast, mRNA expression levels of sclerostin and the inactive form of β-catenin (phosphorylated at Ser33/37/Thr41) were reduced following compressive loading. Following compressive loading of cells, dickkopf-related protein 1 (DKK‑1), an inhibitor of the Wnt signaling pathway, increased protein expression levels of the inactive form of the Wnt‑associated protein, phosphorylated‑β‑catenin, compared with compression alone. However, DVL2 and Wnt1 protein expression levels were unaffected, suggesting that the loading‑induced activation of Wnt/β‑catenin signaling decreased however, it was not prevented by DKK‑1 treatment. In conclusion, the present study demonstrated that cyclic compressive load promoted osteoblast differentiation and may be dependent on the Wnt/β-catenin signaling pathway in regard to magnitude and duration.
Topics: Animals; Cell Differentiation; Cell Line; Mice; Osteoblasts; Stress, Mechanical; Wnt Signaling Pathway; beta Catenin
PubMed: 28447744
DOI: 10.3892/mmr.2017.6327 -
Biochemical and Biophysical Research... May 2017Bone mass is controlled by a balance between bone resorption and formation by osteoclasts and osteoblasts, respectively. An imbalance between osteoblasts and osteoclasts...
Bone mass is controlled by a balance between bone resorption and formation by osteoclasts and osteoblasts, respectively. An imbalance between osteoblasts and osteoclasts increases the risk of osteoporosis and fractures. Although inhibition of osteoclasts is beneficial for preventing and treating osteoporosis, enhanced bone formation through activation of osteoblast differentiation can be a more promising therapeutic approach. In this study, we attempted to isolate small molecules that promote osteoblast differentiation and found that IBIP (3-(2,3-dimethoxyphenyl)-1-[9-methyl-2-phenyl-9H-imidazo[1,2-a]benzimidazol-3-yl]-2-propen-1-one) was a potent activator of osteoblast differentiation. Upon bone morphogenetic protein-2 (BMP2) stimulation, IBIP promoted osteoblast differentiation and increased the expression of osteoblast-specific gene markers, such as osterix and alkaline phosphatase, in a dose-dependent manner. The phosphorylation of SMADs and extracellular signal-regulated kinase (ERK) increased after IBIP treatment. While enhanced SMAD phosphorylation by IBIP was abolished by a BMP inhibitor, IBIP-induced ERK phosphorylation was sustained in the presence of this inhibitor, but was decreased by an ERK kinase inhibitor. Suppression of IBIP-induced SMAD and ERK phosphorylation diminished osteoblast differentiation. Most importantly, IBIP enhanced bone formation and calcification in a BMP2-independent manner in vitro and advanced the skeletal development of zebrafish larvae in vivo. Collectively, IBIP may have beneficial effects on bone loss through potentiation of bone formation.
Topics: 3T3 Cells; Animals; Benzimidazoles; Bone Development; Cell Differentiation; Cell Line; Cells, Cultured; Dose-Response Relationship, Drug; Imidazoles; Mice; Osteoblasts; Osteogenesis; Zebrafish
PubMed: 28419840
DOI: 10.1016/j.bbrc.2017.04.075 -
Biotechnology and Applied Biochemistry Jul 2019Osteoporosis is one of the clinical complications of long-term treatment with glucocorticoids (GCs), characterized by systemic damage of bone mass and osteoblast...
Osteoporosis is one of the clinical complications of long-term treatment with glucocorticoids (GCs), characterized by systemic damage of bone mass and osteoblast dysfunction. Hydrogen sulfide was found to be involved in GCs-induced osteoblast dysfunction. Osteoblastic MC3T3-E1 cell and mitochondrial function were determined by cell viability, M-CSF level, and ALP activity and superoxide production, membrane potential, and ATP level, respectively. The purpose of this research was to explore the impact of NaHS on osteoblastic MC3T3-E1 cell function as well as on Sirt1 and PGC1α expression in dexamethasone (DEX)-treated osteoblast cells. DEX-treated MC3T3-E1 cells exhibited decreased cell viability and ALP activity, as well as increased M-CSF level; all these changes were dramatically attenuated by NaHS. DEX-treated cells also displayed mitochondrial dysfunction, namely decreased mitochondrial membrane potential and ATP generation and increased superoxide generation, which were partly reversed by NaHS. We confirmed decreased Sirt1 and PGC1α protein expression in DEX-treated MC3T3-E1 cells by Western blot, which was also partly reversed by NaHS. Silencing of Sirt1 abrogated the protective effect of NaHS against DEX-induced cell damage and mitochondrial dysfunction. NaHS alleviates DEX-induced osteoblastic MC3T3-E1 cell injury by improving mitochondrial function.
Topics: 3T3 Cells; Animals; Cell Survival; Cells, Cultured; Dexamethasone; Mice; Mitochondria; Osteoblasts; Sulfides
PubMed: 31173404
DOI: 10.1002/bab.1786 -
Journal of Cellular Physiology Jun 2019Osteoblasts are terminally differentiated cells with mesenchymal origins, known to possess pivotal roles in sustaining bone microstructure and homeostasis. These cells... (Review)
Review
Interplay between microRNAs and Wnt, transforming growth factor-β, and bone morphogenic protein signaling pathways promote osteoblastic differentiation of mesenchymal stem cells.
Osteoblasts are terminally differentiated cells with mesenchymal origins, known to possess pivotal roles in sustaining bone microstructure and homeostasis. These cells are implicated in the pathophysiology of various bone disorders, especially osteoporosis. Over the last few decades, strategies to impede bone resorption, principally by bisphosphonates, have been mainstay of treatment of osteoporosis; however, in recent years more attention has been drawn on bone-forming approaches for managing osteoporosis. MicroRNAs (miRNAs) are a broad category of noncoding short sequence RNA fragments that posttranscriptionally regulate the expression of diverse functional and structural genes in a negative manner. An accumulating body of evidence signifies that miRNAs direct mesenchymal stem cells toward osteoblast differentiation and bone formation through bone morphogenic protein, transforming growth factor-β, and Wnt signaling pathways. MiRNAs are regarded as excellent future therapeutic candidates because of their small size and ease of delivery into the cells. Considering their novel therapeutic significance, this review discusses the main miRNAs contributing to the anabolic aspects of bone formation and illustrates their interactions with corresponding signaling pathways involved in osteoblastic differentiation.
Topics: Bone Morphogenetic Proteins; Cell Differentiation; Humans; Mesenchymal Stem Cells; MicroRNAs; Osteoblasts; Osteogenesis; Osteoporosis; Signal Transduction; Transforming Growth Factor beta; Wnt Proteins
PubMed: 30548580
DOI: 10.1002/jcp.27582 -
Biotechnology Letters Feb 2020Mesoporous bioactive glass (MBG) has good biocompatibility without immune reaction after implanting into tissue as biomaterial which was used in the treatment of bone...
OBJECTIVE
Mesoporous bioactive glass (MBG) has good biocompatibility without immune reaction after implanting into tissue as biomaterial which was used in the treatment of bone defect. Genistein (G), a phytoestrogen, could be used in the treatment of osteoporosis in postmenopausal women.
RESULTS
Here, we report that MBG with large pores (MBG-L) and MBG-L adsorbed with G (MBG-L/G) sustained-release G could enhance osteoblast differentiation and matrix mineralization. Interestingly, we observed that MBG-L enhanced the formation of bone-like deposit and Ca deposition in vitro. In the other side, we also found that MBG-L/G substrate could promote osteoblast differentiation and matrix mineralization through Erk activated Runx2 pathway. Interestingly, the expression of osteoblast-specific marker gene Osteopontin (Opn) was also increased in MC3T3-E1 cells cultured on MBG-L/G substrate.
CONCLUSIONS
We conclude that MBG-L/G is a potential biomaterial for the treatment of bone defect.
Topics: Adsorption; Animals; Cell Differentiation; Cell Line; Core Binding Factor Alpha 1 Subunit; Genistein; Glass; Mice; Osteoblasts; Osteogenesis; Osteopontin; Porosity
PubMed: 31776752
DOI: 10.1007/s10529-019-02773-4 -
Experimental & Molecular Medicine Sep 2016Regulation of osteoblast and osteocyte viability is essential for bone homeostasis. Smad4, a major transducer of bone morphogenetic protein and transforming growth...
Regulation of osteoblast and osteocyte viability is essential for bone homeostasis. Smad4, a major transducer of bone morphogenetic protein and transforming growth factor-β signaling pathways, regulates apoptosis in various cell types through a mitochondrial pathway. However, it remains poorly understood whether Smad4 is necessary for the regulation of osteoblast and osteocyte viability. In this study, we analyzed Smad4Δ(Os) mice, in which Smad4 was subjected to tissue-specific disruption under the control of the 2.3-kb Col1a1 promoter, to understand the functional significance of Smad4 in regulating osteoblast/osteocyte viability during bone formation and remodeling. Smad4Δ(Os) mice showed a significant increase in osteoblast number and osteocyte density in the trabecular and cortical regions of the femur, whereas osteoclast activity was significantly decreased. The proliferation of osteoblasts/osteocytes did not alter, as shown by measuring 5'-bromo-2'deoxyuridine incorporation. By contrast, the percentage of TUNEL-positive cells decreased, together with a decrease in the Bax/Bcl-2 ratio and in the proteolytic cleavage of caspase 3, in Smad4Δ(Os) mice. Apoptosis in isolated calvaria cells from Smad4Δ(Os) mice decreased after differentiation, which was consistent with the results of the TUNEL assay and western blotting in Smad4Δ(Os) mice. Conversely, osteoblast cells overexpressing Smad4 showed increased apoptosis. In an apoptosis induction model of Smad4Δ(Os) mice, osteoblasts/osteocytes were more resistant to apoptosis than were control cells, and, consequently, bone remodeling was attenuated. These findings indicate that Smad4 has a significant role in regulating osteoblast/osteocyte viability and therefore controls bone homeostasis.
Topics: Animals; Apoptosis; Bone Resorption; Cell Survival; Cells, Cultured; Female; Homeostasis; Mice; Osteoblasts; Osteocytes; Osteogenesis; Smad4 Protein
PubMed: 27585718
DOI: 10.1038/emm.2016.75 -
Journal of Bone and Mineral Research :... Oct 2020Osteoporosis is an aging-associated disease that is attributed to excessive osteoblast apoptosis. It is known that the accumulation of advanced glycation end products...
Osteoporosis is an aging-associated disease that is attributed to excessive osteoblast apoptosis. It is known that the accumulation of advanced glycation end products (AGEs) in bone extracellular matrix deteriorates osteoblast functions. However, little is known about the interaction between intracellular AGE accumulation and the induction of osteoblast apoptosis. In this study, we investigated the effect of intracellular AGE accumulation on osteoblast apoptosis in vitro and in vivo. In vitro, murine osteoblastic MC3T3-E1 cells were treated with glycolaldehyde (GA), an AGE precursor. GA-induced intracellular AGE accumulation progressed in time- and dose-dependent manners, followed by apoptosis induction. Intracellular AGE formation also activated endoplasmic reticulum (ER) stress-related proteins (such as glucose-regulated protein 78, inositol-requiring protein-1α (IRE1α), and c-Jun N-terminal kinase) and induced apoptosis. In agreement, treatment with the ER stress inhibitor 4-phenylbutyric acid and knocking down IRE1α expression ameliorated osteoblast apoptosis. Furthermore, the ratio between AGE- and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive osteoblasts in human vertebral bodies was significantly higher in an elderly group than in a younger group. A positive linear correlation between the ratio of AGE-positive and TUNEL-positive osteoblasts (r = 0.72) was also observed. Collectively, these results indicate that AGEs accumulated in osteoblasts with age and that intracellular AGE accumulation induces apoptosis via ER stress. These findings offer new insight into the mechanisms of osteoblast apoptosis and age-related osteoporosis. © 2020 American Society for Bone and Mineral Research.
Topics: 3T3 Cells; Animals; Apoptosis; Endoplasmic Reticulum Stress; Endoribonucleases; Glycation End Products, Advanced; Humans; Mice; Osteoblasts; Protein Serine-Threonine Kinases
PubMed: 32427355
DOI: 10.1002/jbmr.4053 -
Endocrine Journal Apr 2024Lipopolysaccharide (LPS) and Receptor Activator of Nuclear Factor-κB Ligand (RANKL) are the two important factors causing bone loss, which is an important pathogenesis...
Lipopolysaccharide (LPS) and Receptor Activator of Nuclear Factor-κB Ligand (RANKL) are the two important factors causing bone loss, which is an important pathogenesis for osteoporosis. However, the relationship between LPS and RANKL is not yet clear. LPS can be involved in the weakened osteoblast formation as an autophagy regulator, and osteoblasts and their precursors are the source cells for RANKL production. Our study aimed to explore the relationship between autophagy changes and RANKL production during LPS-regulated osteoblasts. Our results showed that LPS inhibited autophagy (LC3 conversion and autophagosome formation) and enhanced the protein and mRNA expression of RANKL in MC3T3-E1 osteoblast precursor line. Autophagy upregulation with Rapamycin over BECN1 overexpression rescued LPS-inhibited osteoblast formation and -promoted RANKL protein production in MC3T3-E1 cells. In vivo experiments supported that damaged bone mass, bone microstructure, osteoblastic activity (ALP and P1NP production by ELISA assays) and enhanced RANKL production by LPS administration were partially rescued by Rapamycin application. In conclusion, LPS can inhibit autophagy in osteoblast precursors, thereby inhibiting osteoblast formation and RANKL autophagic degradation.
Topics: Lipopolysaccharides; Osteoblasts; Animals; Autophagy; RANK Ligand; Mice; Cell Line; Osteogenesis; Cell Differentiation; Sirolimus; Male; Beclin-1
PubMed: 38355125
DOI: 10.1507/endocrj.EJ23-0484