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Bone Nov 2016Advancing our understanding of osteoblast biology and differentiation is critical to elucidate the pathological mechanisms responsible for skeletal diseases such as... (Review)
Review
Advancing our understanding of osteoblast biology and differentiation is critical to elucidate the pathological mechanisms responsible for skeletal diseases such as osteoporosis. Histology and histomorphometry, the classical methods to study osteoblast biology, identify osteoblasts based on their location and morphology and ability to mineralize matrix, but do not clearly define their stage of differentiation. Introduction of visual transgenes into the cells of osteoblast lineage has revolutionized the field and resulted in a paradigm shift that allowed for specific identification and isolation of subpopulations within the osteoblast lineage. Knowledge acquired from the studies based on GFP transgenes has allowed for more precise interpretation of studies analyzing targeted overexpression or deletion of genes in the osteoblast lineage. Here, we provide a condensed overview of the currently available promoter-fluorescent reporter transgenic mice that have been generated and evaluated to varying extents. We cover different stages of the lineage as transgenes have been utilized to identify osteoprogenitors, pre-osteoblasts, osteoblasts, or osteocytes. We show that each of these promoters present with advantages and disadvantages. The studies based on the use of these reporter mice have improved our understanding of bone biology. They constitute attractive models to target osteoblasts and help to understand their cell biology.
Topics: Animals; Cell Differentiation; Cell Lineage; Green Fluorescent Proteins; Humans; Luminescent Proteins; Osteoblasts; Osteocytes; Transgenes
PubMed: 27616604
DOI: 10.1016/j.bone.2016.09.004 -
Frontiers in Endocrinology 2020The skeleton is a dynamic and metabolically active organ with the capacity to influence whole body metabolism. This newly recognized function has propagated interest in... (Review)
Review
The skeleton is a dynamic and metabolically active organ with the capacity to influence whole body metabolism. This newly recognized function has propagated interest in the connection between bone health and metabolic dysfunction. Osteoblasts, the specialized mesenchymal cells responsible for the production of bone matrix and mineralization, rely on multiple fuel sources. The utilization of glucose by osteoblasts has long been a focus of research, however, lipids and their derivatives, are increasingly recognized as a vital energy source. Osteoblasts possess the necessary receptors and catabolic enzymes for internalization and utilization of circulating lipids. Disruption of these processes can impair osteoblast function, resulting in skeletal deficits while simultaneously altering whole body lipid homeostasis. This article provides an overview of the metabolism of postprandial and stored lipids and the osteoblast's ability to acquire and utilize these molecules. We focus on the requirement for fatty acid oxidation and the pathways regulating this function as well as the negative impact of dyslipidemia on the osteoblast and skeletal health. These findings provide key insights into the nuances of lipid metabolism in influencing skeletal homeostasis which are critical to appreciate the extent of the osteoblast's role in metabolic homeostasis.
Topics: Animals; Homeostasis; Humans; Lipids; Osteoblasts
PubMed: 33071983
DOI: 10.3389/fendo.2020.578194 -
Journal of Biomedical Materials... Aug 2020Bisphosphonates (BPs) target osteoclasts, slowing bone resorption thus providing rationale to support osseointegration. However, BPs may negatively affect osteoblasts,...
Bisphosphonates (BPs) target osteoclasts, slowing bone resorption thus providing rationale to support osseointegration. However, BPs may negatively affect osteoblasts, impairing peri-implant bone formation. The goal of this study was to assess the effects BPs have on surface-mediated osteogenesis of osteoblasts. MG63 cells were cultured on 15-mm grade 2 titanium disks: smooth, hydrophobic-microrough, or hydrophilic-microrough (Institut Straumann AG, Basel, Switzerland). Tissue culture polystyrene (TCPS) was used as a control. At confluence, cells were treated with 0, 10 , 10 , and 10 M of alendronate, zoledronate, or ibandronate for 24 hr. Sprague Dawley rats were also treated with 1 μg/kg/day ibandronate or phosphate-buffered saline control for 5 weeks. Calvarial osteoblasts (rat osteoblasts [rOBs]) were isolated, characterized, and cultured on surfaces. Osteogenic markers in the media were quantified using ELISAs. BP treatment reduced osteocalcin, osteoprotegerin, osteopontin, bone morphogenetic protein-2, prostaglandin E , transforming growth factor β1, interleukin 10, and vascular endothelial growth factor in MG63 cells. The effect was more robust on rough surfaces, and higher concentrations of BPs stunted production to TCPS/PT levels. Ibandronate conditioned rOBs produced less osteogenic markers similar to direct BP treatment. These results suggest that BP exposure jeopardizes the pro-osteogenic response osteoblasts have to microstructured surfaces. Their effects persist in vivo and negatively condition osteoblast response in vitro. Clinically, BPs could compromise osseointegration.
Topics: Alendronate; Animals; Bone Density Conservation Agents; Cell Count; Cell Line; Cells, Cultured; Diphosphonates; Female; Humans; Ibandronic Acid; Osteoblasts; Osteogenesis; Rats, Sprague-Dawley; Zoledronic Acid
PubMed: 32276287
DOI: 10.1002/jbm.a.36944 -
International Journal of Molecular... Dec 2016Cell death in skeletal component cells, including chondrocytes, osteoblasts, and osteocytes, plays roles in skeletal development, maintenance, and repair as well as in... (Review)
Review
Cell death in skeletal component cells, including chondrocytes, osteoblasts, and osteocytes, plays roles in skeletal development, maintenance, and repair as well as in the pathogenesis of osteoarthritis and osteoporosis. Chondrocyte proliferation, differentiation, and apoptosis are important steps for endochondral ossification. Although the inactivation of and is involved in the pathogenesis of osteosarcomas, the deletion of and inactivation of Rb are insufficient to enhance chondrocyte proliferation, indicating the presence of multiple inhibitory mechanisms against sarcomagenesis in chondrocytes. The inflammatory processes induced by mechanical injury and chondrocyte death through the release of danger-associated molecular patterns (DAMPs) are involved in the pathogenesis of posttraumatic osteoarthritis. The overexpression of increases bone volume with a normal structure and maintains bone during aging by inhibiting osteoblast apoptosis. p53 inhibits osteoblast proliferation and enhances osteoblast apoptosis, thereby reducing bone formation, but also exerts positive effects on osteoblast differentiation through the Akt-FoxOs pathway. Apoptotic osteocytes release ATP, which induces the receptor activator of nuclear factor κ-B ligand (Rankl) expression and osteoclastogenesis, from pannexin 1 channels. Osteocyte death ultimately results in necrosis; DAMPs are released to the bone surface and promote the production of proinflammatory cytokines, which induce Rankl expression, and osteoclastogenesis is further enhanced.
Topics: Alarmins; Animals; Apoptosis; Chondrocytes; Humans; Osteoblasts; Osteocytes
PubMed: 27929439
DOI: 10.3390/ijms17122045 -
Nutrients Apr 2023Osteoblasts and osteoclasts play crucial roles in bone formation and bone resorption. We found that plum-derived exosome-like nanovesicles (PENVs) suppressed osteoclast...
Osteoblasts and osteoclasts play crucial roles in bone formation and bone resorption. We found that plum-derived exosome-like nanovesicles (PENVs) suppressed osteoclast activation and modulated osteoblast differentiation. PENVs increased the proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells and osteoblasts from mouse bone marrow cultures. Notably, PENVs elevated the expression of osteoblastic transcription factors and osteoblast differentiation marker proteins in MC3T3-E1 cells. Higher levels of phosphorylated BMP-2, p38, JNK, and smad1 proteins were detected in PENV-treated MC3T3-E1 cells. Additionally, the number of TRAP-positive cells was significantly decreased in PENV-treated osteoclasts isolated from osteoblasts from mouse bone marrow cultures. Importantly, osteoclastogenesis of marker proteins such as PPAR-gamma, NFATc1, and c-Fos were suppressed by treatment with PENVs (50 μg/mL). Taken together, these results demonstrate that PENVs can be used as therapeutic targets for treating bone-related diseases by improving osteoblast differentiation and inhibiting osteoclast activation for the first time.
Topics: Animals; Mice; Osteoclasts; Prunus domestica; Exosomes; Osteoblasts; Cell Differentiation; Bone Diseases
PubMed: 37432256
DOI: 10.3390/nu15092107 -
Bone May 2023FBXO11 is the substrate-recognition component of a ubiquitin ligase complex called SKP1-cullin-F-boxes. The role of FBXO11 in bone development is unexplored. In this...
FBXO11 is the substrate-recognition component of a ubiquitin ligase complex called SKP1-cullin-F-boxes. The role of FBXO11 in bone development is unexplored. In this study, we reported a novel mechanism of how bone development is regulated by FBXO11. FBXO11 gene knockdown by lentiviral transduction in mouse pre-osteoblast MC3T3-E1 cells leads to reduced osteogenic differentiation, while overexpressing FBXO11 accelerates their osteogenic differentiation in vitro. Furthermore, we generated two osteoblastic-specific FBXO11 conditional knockout mouse models, Col1a1-ERT2-FBXO11KO and Bglap2-FBXO11KO mice. In both conditional FBXO11KO mouse models, we found FBXO11 deficiency inhibits normal bone growth, in which the osteogenic activity in FBXO11cKO mice is reduced, while osteoclastic activity is not significantly changed. Mechanistically, we found FBXO11 deficiency leads to Snail1 protein accumulation in osteoblasts, leading to suppression of osteogenic activity and inhibition of bone matrix mineralization. FBXO11 knockdown in MC3T3-E1 cells reduced Snail1 protein ubiquitination and increased Snail1 protein accumulation in the cells, which eventually inhibited osteogenic differentiation. In conclusion, FBXO11 deficiency in osteoblasts inhibits bone formation through Snail1 accumulation, inhibiting osteogenic activity and bone mineralization.
Topics: Animals; Mice; Osteogenesis; Cell Differentiation; Calcification, Physiologic; Osteoclasts; Osteoblasts
PubMed: 36863499
DOI: 10.1016/j.bone.2023.116709 -
Frontiers in Cellular and Infection... 2015Bone cells, namely osteoblasts and osteoclasts work in concert and are responsible for bone extracellular matrix formation and resorption. This homeostasis is, in part,... (Review)
Review
Bone cells, namely osteoblasts and osteoclasts work in concert and are responsible for bone extracellular matrix formation and resorption. This homeostasis is, in part, altered during infections by Staphylococcus aureus through the induction of various responses from the osteoblasts. This includes the over-production of chemokines, cytokines and growth factors, thus suggesting a role for these cells in both innate and adaptive immunity. S. aureus decreases the activity and viability of osteoblasts, by induction of apoptosis-dependent and independent mechanisms. The tight relationship between osteoclasts and osteoblasts is also modulated by S. aureus infection. The present review provides a survey of the relevant literature discussing the important aspects of S. aureus and osteoblast interaction as well as the ability for antimicrobial peptides to kill intra-osteoblastic S. aureus, hence emphasizing the necessity for new anti-infectious therapeutics.
Topics: Animals; Antimicrobial Cationic Peptides; Apoptosis; Cell Survival; Host-Pathogen Interactions; Humans; Immunity, Innate; Microbial Viability; Osteoblasts; Osteoclasts; Osteomyelitis; Staphylococcal Infections; Staphylococcus aureus
PubMed: 26636047
DOI: 10.3389/fcimb.2015.00085 -
STAR Protocols Jun 2021Mesenchymal-derived osteoblasts play a key role in bone formation via synthesis and mineralization of the bone and bone remodeling. Osteoclasts are multinucleated cells...
Mesenchymal-derived osteoblasts play a key role in bone formation via synthesis and mineralization of the bone and bone remodeling. Osteoclasts are multinucleated cells of hematopoietic origin with a role in bone resorption. Here, we describe a protocol for generating primary cultures of these two cell types from bone tissue including the femur, tibia, and humerus of young mice. We describe methods for addressing their activity and/or differentiation, enabling studying the effects of various treatments during or following differentiation . For further practical example of using these protocols, please refer to Chevalier et al. (2020).
Topics: Animals; Mice; Osteoblasts; Osteoclasts; Primary Cell Culture
PubMed: 33912848
DOI: 10.1016/j.xpro.2021.100452 -
International Journal of Molecular... Jan 2021Notch1-4 receptors and their signaling pathways are expressed in almost all organ systems and play a pivotal role in cell fate decision by coordinating cell... (Review)
Review
Notch1-4 receptors and their signaling pathways are expressed in almost all organ systems and play a pivotal role in cell fate decision by coordinating cell proliferation, differentiation and apoptosis. Differential expression and activation of Notch signaling pathways has been observed in a variety of organs and tissues under physiological and pathological conditions. Bone tissue represents a dynamic system, which is constantly remodeled throughout life. In bone, Notch receptors have been shown to control remodeling and regeneration. Numerous functions have been assigned to Notch receptors and ligands, including osteoblast differentiation and matrix mineralization, osteoclast recruitment and cell fusion and osteoblast/osteoclast progenitor cell proliferation. The expression and function of Notch1-4 in the skeleton are distinct and closely depend on the temporal expression at different differentiation stages. This review addresses the current knowledge on Notch signaling in adult bone with emphasis on metabolism, bone regeneration and degenerative skeletal disorders, as well as congenital disorders associated with mutant Notch genes. Moreover, the crosstalk between Notch signaling and other important pathways involved in bone turnover, including Wnt/β-catenin, BMP and RANKL/OPG, are outlined.
Topics: Animals; Bone Regeneration; Bone and Bones; Humans; Osteoblasts; Osteoclasts; Osteocytes; Receptors, Notch; Signal Transduction
PubMed: 33572704
DOI: 10.3390/ijms22031325 -
International Journal of Molecular... May 2021Gut microbiota has emerged as an important regulator of bone homeostasis. In particular, the modulation of innate immunity and bone homeostasis is mediated through the... (Review)
Review
Gut microbiota has emerged as an important regulator of bone homeostasis. In particular, the modulation of innate immunity and bone homeostasis is mediated through the interaction between microbe-associated molecular patterns (MAMPs) and the host pattern recognition receptors including Toll-like receptors and nucleotide-binding oligomerization domains. Pathogenic bacteria such as and tend to induce bone destruction and cause various inflammatory bone diseases including periodontal diseases, osteomyelitis, and septic arthritis. On the other hand, probiotic bacteria such as and species can prevent bone loss. In addition, bacterial metabolites and various secretory molecules such as short chain fatty acids and cyclic nucleotides can also affect bone homeostasis. This review focuses on the regulation of osteoclast and osteoblast by MAMPs including cell wall components and secretory microbial molecules under in vitro and in vivo conditions. MAMPs could be used as potential molecular targets for treating bone-related diseases such as osteoporosis and periodontal diseases.
Topics: Animals; Cell Differentiation; Gastrointestinal Microbiome; Homeostasis; Humans; Osteoblasts; Osteoclasts; Osteocytes; Receptors, Pattern Recognition; Toll-Like Receptors
PubMed: 34071605
DOI: 10.3390/ijms22115805