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BMB Reports Jul 2019Kruppel-like factor 2 (KLF2) has been implicated in the regulation of cell proliferation, differentiation, and survival in a variety of cells. Recently, it has been...
Kruppel-like factor 2 (KLF2) has been implicated in the regulation of cell proliferation, differentiation, and survival in a variety of cells. Recently, it has been reported that KLF2 regulates the p65-mediated transactivation of NF-κB. Although the NF-κB pathway plays an important role in the differentiation of osteoclasts and osteoblasts, the role of KLF2 in these bone cells has not yet been fully elucidated. In this study, we demonstrated that KLF2 regulates osteoclast and osteoblast differentiation. The overexpression of KLF2 in osteoclast precursor cells inhibited osteoclast differentiation by downregulating c-Fos, NFATc1, and TRAP expression, while KLF2 overexpression in osteoblasts enhanced osteoblast differentiation and function by upregulating Runx2, ALP, and BSP expression. Conversely, the downregulation of KLF2 with KLF2-specific siRNA increased osteoclast differentiation and inhibited osteoblast differentiation. Moreover, the overexpression of interferon regulatory protein 2-binding protein 2 (IRF2BP2), a regulator of KLF2, suppressed osteoclast differentiation and enhanced osteoblast differentiation and function. These effects were reversed by downregulating KLF2. Collectively, our data provide new insights and evidence to suggest that the IRF2BP2/KLF2 axis mediates osteoclast and osteoblast differentiation, thereby affecting bone homeostasis. [BMB Reports 2019; 52(7): 469-474].
Topics: Cell Differentiation; DNA-Binding Proteins; Homeostasis; Humans; Kruppel-Like Transcription Factors; Osteoblasts; Osteoclasts; Transcription Factors
PubMed: 31186082
DOI: 10.5483/BMBRep.2019.52.7.104 -
Cell Reports Sep 2020Osteoprotegerin (OPG) is a circulating decoy receptor for RANKL, a multifunctional cytokine essential for the differentiation of tissue-specific cells in bone and immune...
Osteoprotegerin (OPG) is a circulating decoy receptor for RANKL, a multifunctional cytokine essential for the differentiation of tissue-specific cells in bone and immune systems such as osteoclasts, medullary thymic epithelial cells (mTECs), and intestinal microfold cells (M cells). However, it is unknown whether OPG functions only at the production site or circulates to other tissues acting in an endocrine fashion. Here we explore the cellular source of OPG by generating OPG-floxed mice and show that locally produced OPG, rather than circulating OPG, is crucial for bone and immune homeostasis. Deletion of OPG in osteoblastic cells leads to severe osteopenia without affecting serum OPG. Deletion of locally produced OPG increases mTEC and M cell numbers while retaining the normal serum OPG level. This study shows that OPG limits its functions within the tissue where it was produced, illuminating the importance of local regulation of the RANKL system.
Topics: Animals; Mice; Osteoblasts; Osteoclasts; Osteoprotegerin
PubMed: 32905763
DOI: 10.1016/j.celrep.2020.108124 -
Cellular and Molecular Life Sciences :... Apr 2015Several metabolic, genetic and oncogenic bone diseases are characterized by defective or excessive bone formation. These abnormalities are caused by dysfunctions in the... (Review)
Review
Several metabolic, genetic and oncogenic bone diseases are characterized by defective or excessive bone formation. These abnormalities are caused by dysfunctions in the commitment, differentiation or survival of cells of the osteoblast lineage. During the recent years, significant advances have been made in our understanding of the cellular and molecular mechanisms underlying the osteoblast dysfunctions in osteoporosis, skeletal dysplasias and primary bone tumors. This led to suggest novel therapeutic approaches to correct these abnormalities such as the modulation of WNT signaling, the pharmacological modulation of proteasome-mediated protein degradation, the induction of osteoprogenitor cell differentiation, the repression of cancer cell proliferation and the manipulation of epigenetic mechanisms. This article reviews our current understanding of the major cellular and molecular mechanisms inducing osteoblastic cell abnormalities in age-related bone loss, genetic skeletal dysplasias and primary bone tumors, and discusses emerging therapeutic strategies to counteract the osteoblast abnormalities in these disorders of bone formation.
Topics: Apoptosis; Bone Diseases, Developmental; Bone Neoplasms; Cell Differentiation; Humans; Models, Biological; Osteoblasts; Osteoporosis; Signal Transduction
PubMed: 25487608
DOI: 10.1007/s00018-014-1801-2 -
International Journal of Molecular... Jan 2020As the population of western societies on average ages, the number of people affected by bone remodeling-associated diseases such as osteoporosis continues to increase.... (Review)
Review
As the population of western societies on average ages, the number of people affected by bone remodeling-associated diseases such as osteoporosis continues to increase. The development of new therapeutics is hampered by the high failure rates of drug candidates during clinical testing, which is in part due to the poor predictive character of animal models during preclinical drug testing. Co-culture models of osteoblasts and osteoclasts offer an alternative to animal testing and are considered to have the potential to improve drug development processes in the future. However, a robust, scalable, and reproducible 3D model combining osteoblasts and osteoclasts for preclinical drug testing purposes has not been developed to date. Here we review various types of osteoblast-osteoclast co-culture models and outline the remaining obstacles that must be overcome for their successful translation.
Topics: Animals; Bone Density Conservation Agents; Bone Remodeling; Coculture Techniques; Drug Evaluation, Preclinical; Humans; Osteoblasts; Osteoclasts; Osteoporosis
PubMed: 32019244
DOI: 10.3390/ijms21030912 -
International Journal of Biological... 2020The roles of long non-coding RNAs (lncRNAs) and micro RNAs (miRNAs) as regulators of mRNA expression in various diseases have recently been reported. Osteoblast...
The roles of long non-coding RNAs (lncRNAs) and micro RNAs (miRNAs) as regulators of mRNA expression in various diseases have recently been reported. Osteoblast differentiation is the vital process which mediates bone formation and fracture healing. In present study, we found microRNA-6979-5p (miR-6979-5p) to be the most differentially expressed miRNA between normal bone and calluses of mice, and overexpression of miR-6979-5p was negatively associated with osteoblast differentiation. Through luciferase assays, we found evidence that bone morphogenetic protein 2 (BMP2) is a miR-6979-5p target gene that positively regulates osteoblast differentiation. We further identified the lncRNA Rhno1 as a competing endogenous RNA (ceRNA) of miR-6979-5p, and we verified that it was able to influence osteoblast differentiation both and . In summary, our data indicates that the lncRNA Rhno1/miR-6979-5p/BMP2 axis is a significant regulatory mechanism controlling osteoblast differentiation, and it may thus offer a novel therapeutic strategy for fracture healing.
Topics: Animals; Bone Morphogenetic Protein 2; Cell Differentiation; Fracture Healing; Gene Expression Regulation; Male; Mice, Inbred C57BL; Osteoblasts; RNA, Long Noncoding
PubMed: 32226305
DOI: 10.7150/ijbs.38930 -
Anatomical Science International Sep 2023Osteoblasts alignment and migration are involved in the directional formation of bone matrix and bone remodeling. Many studies have demonstrated that mechanical...
Osteoblasts alignment and migration are involved in the directional formation of bone matrix and bone remodeling. Many studies have demonstrated that mechanical stretching controls osteoblast morphology and alignment. However, little is known about its effects on osteoblast migration. Here, we investigated changes in the morphology and migration of preosteoblastic MC3T3-E1 cells after the removal of continuous or cyclic stretching. Actin staining and time-lapse recording were performed after stretching removal. The continuous and cyclic groups showed parallel and perpendicular alignment to the stretch direction, respectively. A more elongated cell morphology was observed in the cyclic group than in the continuous group. In both stretch groups, the cells migrated in a direction roughly consistent with the cell alignment. Compared to the other groups, the cells in the cyclic group showed an increased migration velocity and were almost divided in the same direction as the alignment. To summarize, our study showed that mechanical stretching changed cell alignment and morphology in osteoblasts, which affected the direction of migration and cell division, and velocity of migration. These results suggest that mechanical stimulation may modulate the direction of bone tissue formation by inducing the directional migration and cell division of osteoblasts.
Topics: Actins; Osteoblasts; Bone and Bones; Cell Division
PubMed: 37022568
DOI: 10.1007/s12565-023-00716-8 -
PloS One 2018MicroRNAs (miRNAs) are important regulators of many cellular processes, including the differentiation and activity of osteoblasts, and therefore, of bone turnover....
MicroRNAs (miRNAs) are important regulators of many cellular processes, including the differentiation and activity of osteoblasts, and therefore, of bone turnover. MiR-320a is overexpressed in osteoporotic bone tissue but its role in osteoblast function is unknown. In the present study, functional assays were performed with the aim to elucidate the mechanism of miR-320a action in osteoblastic cells. MiR-320a was either overexpressed or inhibited in human primary osteoblasts (hOB) and gene expression changes were evaluated through microarray analysis. In addition, the effect of miR-320a on cell proliferation, viability, and oxidative stress in hOB was evaluated. Finally, matrix mineralization and alkaline phosphatase activity were assessed in order to evaluate osteoblast functionality. Microarray results showed miR-320a regulation of a number of key osteoblast genes and of genes involved in oxidative stress. Regulation of osteoblast differentiation and ossification appeared as the best significant biological processes (PANTHER P value = 3.74E-05; and P value = 3.06E-04, respectively). The other enriched pathway was that of the cellular response to cadmium and zinc ions, mostly by the overexpression of metallothioneins. In hOBs, overexpression of miR-320a increased cell proliferation and oxidative stress levels whereas mineralization capacity was reduced. In conclusion, overexpression of miR-320a increased stress oxidation levels and was associated with reduced osteoblast differentiation and functionality, which could trigger an osteoporotic phenotype.
Topics: Cell Differentiation; Cell Proliferation; Cells, Cultured; Gene Expression Regulation; Humans; MicroRNAs; Osteoblasts; Osteoporosis; Oxidative Stress; Up-Regulation
PubMed: 30485349
DOI: 10.1371/journal.pone.0208131 -
Scientific Reports Jul 2020Current research on surface modifications has yielded advanced implant biomaterials. Various implant surface modifications have been shown to be promising in improving...
Current research on surface modifications has yielded advanced implant biomaterials. Various implant surface modifications have been shown to be promising in improving bone target cell response, but more comprehensive studies whether certain implant surface modifications can directly target cell behavioural features such as morphogenesis and proliferation are needed. Here, we studied the response of primary alveolar bone cells on various implant surface modifications in terms of osteoblast morphology and proliferation in vitro. Analyses of surface modifications led to surface-related test parameters including the topographical parameters micro-roughness, texture aspect and surface enlargement as well as the physicochemical parameter surface wettability. We compared osteoblast morphology and proliferation towards the above-mentioned parameters and found that texture aspect and surface enlargement but not surface roughness or wettability exhibited significant impact on osteoblast morphology and proliferation. Detailed analysis revealed osteoblast proliferation as a function of cell morphology, substantiated by an osteoblast size- and morphology-dependent increase in mitotic activity. These findings show that implant surface topography controls cell behavioural morphology and subsequently cell proliferation, thereby opening the road for cell instructive biomaterials.
Topics: Alveolar Process; Biocompatible Materials; Cell Proliferation; Cell Size; Cells, Cultured; Humans; Mitosis; Osteoblasts; Prostheses and Implants; Surface Properties; Wettability
PubMed: 32732908
DOI: 10.1038/s41598-020-69685-6 -
Aging Cell Feb 2021Impaired osteoblast function is involved in osteoporosis, and microRNA (miRNA) dysregulation may cause abnormal osteoblast osteogenic activity. However, the influence of...
Impaired osteoblast function is involved in osteoporosis, and microRNA (miRNA) dysregulation may cause abnormal osteoblast osteogenic activity. However, the influence of miRNA on osteoblast activity and the underlying mechanisms remain elusive. In this study, miR-103-3p was found to be negatively correlated with bone formation in bone specimens from elderly women with fractures and ovariectomized (OVX) mice. Additionally, miR-103-3p directly targeted Mettl14 to inhibit osteoblast activity, and METTL14-dependent N -methyladenosine (m A) methylation inhibited miR-103-3p processing by the microprocessor protein DGCR8 and promoted osteoblast activity. Moreover, miR-103-3p inhibited bone formation in vivo, and therapeutic inhibition of miR-103-3p counteracted the decreased bone formation in OVX mice. Further, METTL14 was negatively correlated with miR-103-3p but positively correlated with bone formation in bone specimens from elderly women with fractures and OVX mice. Collectively, our results highlight the critical roles of the miR-103-3p/METTL14/m A signaling axis in osteoblast activity, identifying this axis as a potential target for ameliorating osteoporosis.
Topics: Animals; Bone Resorption; Methyltransferases; Mice; MicroRNAs; Osteoblasts
PubMed: 33440070
DOI: 10.1111/acel.13298 -
International Journal of Molecular... Feb 2023The surface topography of titanium dental implants has a great influence on osseointegration. In this work, we try to determine the osteoblastic behavior and gene...
The surface topography of titanium dental implants has a great influence on osseointegration. In this work, we try to determine the osteoblastic behavior and gene expression of cells with different titanium surfaces and relate them to the physicochemical properties of the surface. For this purpose, we have used commercial titanium discs of grade 3: as-received corresponds to machined titanium without any surface treatment (MA), chemically acid etched (AE), treated via sand blasting with AlO particles (SB) and a sand-blasting treatment with acid etching (SB+AE). The surfaces have been observed using scanning electron microscopy (SEM) and the roughness, wettability and surface energy with dispersive and polar components have been characterized. Osteoblastic cultures were performed with SaOS-2 osteoblastic cells determining cell viability as well as alkaline phosphatase levels for 3 and 21 days, and osteoblastic gene expression was determined. The roughness values of the MA discs was 0.02 μm, which increases to 0.3 μm with acid attack and becomes the maximum for the sand-blasted samples, reaching values of 1.2 μm for SB and SB+AE. The hydrophilic behavior of the MA and AE samples with contact angles of 63° and 65° is superior to that of the rougher samples, being 75° for SB and 82° for SB+AE. In all cases, they show good hydrophilicity. GB and GB+AE surfaces present a higher polar component in the surface energy values, 11.96 and 13.18 mJ/m, respectively, than AE and MA, 6.64 and 9.79 mJ/m, respectively. The osteoblastic cell viability values at three days do not show statistically significant differences between the four surfaces. However, the viability of the SB and SB+AE surfaces at 21 days is much higher than that of the AE and MA samples. From the alkaline phosphatase studies, higher values were observed for those treated with sand blasting with and without acid etching compared to the other two surfaces, indicating a greater activity in osteoblastic differentiation. In all cases except in the Osterix (Ostx) -osteoblast-specific transcription factor-a decrease in gene expression is observed in relation to the MA samples (control). The most important increase was observed for the SB+AE condition. A decrease in the gene expression of Osteoprotegerine (OPG), Runt-related transcription factor 2 (Runx2), Receptor Activator of NF-κB Ligand (RANKL) and Alkaline Phosphatase (Alp) genes was observed in the AE surface.
Topics: Alkaline Phosphatase; Cell Differentiation; Cell Proliferation; Gene Expression; Microscopy, Electron, Scanning; Osteoblasts; Surface Properties; Titanium; Bone and Bones
PubMed: 36834936
DOI: 10.3390/ijms24043523