Search Results (1,414)

Triphenyl phosphate (TPhP) is a widely used organophosphate flame retardant and plasticizer, raising concerns over its health impacts. This study examined the effects of embryonic TPhP exposure on axial skeletal development and metabolism in medaka (Oryzias latipes), a vertebrate fish model relevant to human bone biology. Medaka embryos were exposed to 1 µM TPhP and assessed through early larval stages. TPhP impaired vertebral ossification, causing shortened centra and reduced cartilage in the caudal complex, alongside disrupted distribution of osteoblast-lineage cells. Key osteogenic genes were significantly downregulated at 14 days post fertilization, and transcriptomic analysis revealed altered mitochondrial pathways linked to skeletal disorders. Functionally, TPhP-exposed larvae showed reduced caudal fin regeneration and decreased metabolic rate and oxygen consumption, consistent with mitochondrial dysfunction. These findings indicate that TPhP disrupts bone development and metabolism by affecting osteoblast differentiation and mitochondrial regulation, highlighting the value of small fish models for studying environmental toxicants and bone metabolic disease risk. Full article

Xylosyltransferase-I (XT-I) plays a crucial role in skeletal development and cartilage integrity. An XT-I deficiency is linked to severe bone disorders, such as Desbuquois dysplasia type 2. While animal models have provided insights into XT-I’s role during skeletal development, its specific effects on adult bone homeostasis, particularly in human mesenchymal stem cell (hMSC) differentiation, remain unclear. This study investigates how XT-I deficiency impacts the differentiation of hMSCs into chondrocytes, osteoblasts, and adipocytes—key processes in bone formation and repair. The aim of this study was to elucidate for the first time the molecular mechanisms by which XT-I deficiency leads to impaired bone homeostasis. Using CRISPR-Cas9-mediated gene editing, we generated XYLT1 knockdown (KD) hMSCs to assess their differentiation potential. Our findings revealed significant disruption in the chondrogenic differentiation in KD hMSCs, characterized by the altered expression of regulatory factors and extracellular matrix components, suggesting premature chondrocyte hypertrophy. Despite the presence of perilipin-coated lipid droplets in the adipogenic pathway, the overall leptin mRNA and protein expression was reduced in KD hMSCs, indicating a compromised lipid metabolism. Conversely, osteogenic differentiation was largely unaffected, with KD and wild-type hMSCs exhibiting comparable mineralization processes, indicating that critical aspects of osteogenesis were preserved despite the XYLT1 deficiency. In summary, these results underscore XT-I’s pivotal role in regulating differentiation pathways within the bone marrow niche, influencing cellular functions critical for skeletal health. A deeper insight into bone biology may pave the way for the development of innovative therapeutic approaches to improve bone health and treat skeletal disorders. Full article

Osteoclastogenesis—the activation and differentiation of osteoclasts—is one of the pivotal processes of bone remodeling and is regulated by RANKL/RANK signaling, the decoy function of osteoprotegerin (OPG), and a cascade of pro- and anti-inflammatory cytokines. The disruption of this balance leads to pathological bone loss in diseases such as osteoporosis and rheumatoid arthritis. FFAR4 (Free Fatty Acid Receptor 4), a G protein-coupled receptor for long-chain omega-3 fatty acids, has been confirmed as a key mediator of metabolic and anti-inflammatory effects. This review focuses on how FFAR4 acts as the selective receptor for the omega-3 fatty acid docosahexaenoic acid (DHA). It activates two divergent signaling pathways. The Gαq-dependent cascade facilitates intracellular calcium mobilization and ERK1/2 activation. Meanwhile, β-arrestin-2 recruitment inhibits NF-κB. These collective actions reshape the cytokine environment. In macrophages, DHA–FFAR4 signaling lowers the levels of TNF-α, interleukin-6 (IL-6), and IL-1β while increasing IL-10 secretion. Consequently, the activation of NFATc1 and NF-κB p65 is profoundly suppressed under TNF-α or RANKL stimulation. Additionally, DHA modulates the RANKL/OPG axis in osteoblastic cells by suppressing RANKL expression, thereby reducing osteoclast differentiation in an inflammatory mouse model. Full article

Osteolforte, a compound with potential bone-regenerative properties, was investigated for its effects on human bone marrow stromal cells (hBMSCs). This study aimed to evaluate its impact on cell viability, osteogenic differentiation, and both gene and protein expression using a combination of assays, including CCK-8, Alizarin Red S staining, Quantitative Real-Time PCR (qRT-PCR), and Western blot analysis. The results demonstrated that Osteolforte significantly enhanced osteogenic differentiation in hBMSCs. Alizarin Red S staining revealed increased mineralization, indicating elevated calcium deposition. Gene expression analysis showed an upregulation of key osteogenic markers, including runt-related transcription factor-2 (RUNX-2), collagen type I (COL-1), and bone morphogenetic protein-2 (BMP-2), supporting the role of Osteolforte in promoting osteoblastic activity. In particular, the elevated expression of RUNX-2—a master transcription factor in osteoblast differentiation along with COL-1, a major bone matrix component, and BMP-2, a key bone morphogenetic protein—highlights the compound’s osteogenic potential. In conclusion, Osteolforte enhances early-stage osteogenesis and mineralization in hBMSCs and represents a promising candidate for bone regeneration. Full article

Senescent cells secrete pro-inflammatory cytokines, collectively referred to as the senescence-associated secretory phenotype (SASP). Certain pro-inflammatory SASP factors are known to inhibit the differentiation of bone-forming osteoblast while promoting the differentiation of bone-resorbing osteoclasts, thereby causing osteoporosis. In this study, we screened cabozantinib, a tyrosine kinase inhibitor used to treat medullary thyroid cancer, for its ability to reduce doxorubicin-induced cellular senescence in both osteoblast and osteoclast progenitors. This non-cytotoxic agent suppressed the secretion of SASP factors (e.g., TNFα, IL1α, IL1β, IL6, and CCL2) from senescent osteoblast and osteoclast progenitors, resulting in enhanced osteoblast differentiation and reduced osteoclast differentiation. Furthermore, intraperitoneal administration of cabozantinib to age-related estrogen-deficient mice subjected to ovariectomy prevented bone loss without apparent side effects, increasing osteoblast numbers and reducing osteoclast numbers along the surface of the trabecular bone. In summary, our findings suggest that anti-aging cabozantinib has potential as a preventive anti-osteoporotic agent by promoting osteogenesis and inhibiting osteoclastogenesis through the repression of SASP. Full article

Tea is one of the most consumed beverages in the world, belonging to the category of compounds known as tannins and flavonoids. One of the polyphenols found in large amounts in green tea leaves (Camellia sinensis) is epigallocatechin-3-O-gallate (EGCG). Though EGCG has shown some pharmacological effects, to date, it has not been utilised as a therapeutic agent. This is attributed to the fact that EGCG lacks adequate stability, and it is known to degrade through epimerization or auto-oxidation processes, especially when it is exposed to light, temperature fluctuations, some pH values, or the presence of oxygen. Consuming green tea with EGCG can alleviate the effects of bone diseases, such as osteoporosis, and support faster bone regeneration in the case of fractures. Therefore, this review focuses on the current state of research, highlighting the effects of EGCG on bone biology, such as enhancing osteoblast differentiation, promoting bone mineralisation, improving bone microarchitecture, and inhibiting osteoclastogenesis through the modulation of the RANK/RANKL/OPG pathway. Additionally, EGCG exerts antioxidant, anti-inflammatory, and dose-dependent effects on bone cells. It also downregulates inflammatory markers (TNF-α, IL-1β, and COX-2) and reduces oxidative stress via the inhibition of reactive oxygen species generation and the activation of protective signalling pathways (e.g., MAPK and NF-κB). Studies in animal models confirm that EGCG supplementation leads to increased bone mass and strength. These findings collectively support the further exploration of EGCG as an adjunct in the treatment and prevention of metabolic bone diseases. The authors aim to present the relationship between EGCG and bone health, highlighting issues for future research and clinical applications. Full article

Bone tissue regeneration is a complex process that takes place at the level of osteoblasts derived from mesenchymal cells and occurs under the action of multiple signaling pathways and through the expression of osteoregenerative markers. The leaf extract of Juglans regia L. (JR) is rich in polyphenols with demonstrated osteoregeneration effects. In the present study, we investigated the extract’s effects on three types of cells with various stages of differentiation: adult mesenchymal stem cells (MSCs), osteoblasts at low passage (O6) and osteoblasts at advanced passage (O10). To assess the efficacy of the walnut leaf extract, in vitro treatments were performed in comparison with ellagic acid (EA) and catechin (CAT). The osteoregenerative properties of the leaf extract were evaluated in terms of cell viability, bone mineralization (by staining with alizarin red) and the expression of osteogenesis markers such as osteocalcin (OC), osteopontin (OPN), dentin matrix acidic phosphoprotein 1 (DMP1) and collagen type 1A. Another compound implicated in oxidative stress response, but also a bone homeostasis regulator, nuclear factor erythroid 2-related factor 2 (NRF2), was studied by immunocytochemistry. Together with collagen amount, alkaline phosphatase (ALP) activity and NF-kB levels were measured in cell lysates and supernatants. The obtained results demonstrate that JR treatment induced osteogenic differentiation and bone mineralization, and it showed protective effects against oxidative stress. Full article

β-catenin is a key regulator of osteoblast differentiation, proliferation, and bone homeostasis. Through its interaction with transcription factors such as TCF/LEF, Runx2, and Osx, it coordinates gene expression essential for osteogenesis. The aim of this review is to demonstrate how β-catenin signaling is modulated by various physiological and pathological factors, including mechanical loading, oxidative stress, HIV-1 gp120, fluoride, implant topography, and microRNAs. These factors influence Wnt/β-catenin signaling through different mechanisms, often exerting opposing effects on osteoblast function. By integrating these modulators, we provide a comprehensive view of the dynamic regulation of β-catenin in bone biology. Understanding this complexity may provide insight into novel therapeutic strategies targeting β-catenin in bone regeneration, metabolic bone diseases, and pathologies such as HIV-associated bone loss or osteosarcoma. Full article

This study investigated the effects of local fibroblast growth factor (FGF)-2 application on periodontal healing in an osteoporotic model, both in vivo and in vitro. Wistar rats were divided into the ovariectomy (OVX) and Control groups. Periodontal defects were created 8 weeks post-OVX and treated with hydroxypropylcellulose (HPC) or FGF-2 + HPC. Healing was evaluated through micro-computed tomography and histological analyses at 2 and 4 weeks. In vitro, bone marrow mesenchymal stromal cells (BMSCs) were cultured with/without FGF-2 and assessed for cell morphology, viability/proliferation, and osteoblastic marker expression. Alkaline phosphatase (ALP) staining was also performed. FGF-2-treated defects in both groups showed significantly greater bone volume fraction, trabecular number, and thickness compared to HPC only. Histologically, FGF-2 enhanced new bone formation, with the greatest levels in the Control group. In vitro, OVX BMSCs showed reduced actin staining versus controls. FGF-2 increased cell viability/proliferation and protrusions in both groups while downregulating Alpl and Bglap expression levels and reducing ALP-positive cells. FGF-2 increased new bone formation in the OVX group, stimulated proliferation of OVX BMSCs, and modulated their differentiation. FGF-2 could enhance periodontal healing even under osteoporotic conditions, albeit to a lesser extent. Full article

Tanshinones are a class of lipophilic diterpenoid quinones extracted from Salvia miltiorrhiza (Dan shen), a widely used herb in traditional Chinese medicine. These compounds, particularly tanshinone IIA (T-IIA) and sodium tanshinone sulfonate (STS), have been acknowledged for their broad spectrum of biological activities, including anti-inflammatory, antioxidant, anti-tumor, antiresorptive, and antimicrobial effects. Recent studies have highlighted the potential of tanshinones in the treatment of osteolytic diseases, characterized by excessive bone resorption, such as osteoporosis, rheumatoid arthritis, and periodontitis. The therapeutic effects of tanshinones in these diseases are primarily attributed to their ability to inhibit osteoclast differentiation and activity, suppress inflammatory cytokine production (e.g., tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6), and modulate critical signaling pathways, including NF-kB, MAPK, PI3K/Akt, and the RANKL/RANK/OPG axis. Additionally, tanshinones promote osteoblast differentiation and mineralization by enhancing the expression of osteogenic markers such as Runx2, ALP, and OCN. Preclinical models have demonstrated that T-IIA and STS can significantly reduce bone destruction and inflammatory cell infiltration in arthritic joints and periodontal tissues while also enhancing bone microarchitecture in osteoporotic conditions. This review aims to provide a comprehensive overview of the pharmacological actions of tanshinones in osteolytic diseases, summarizing current experimental findings, elucidating underlying molecular mechanisms, and discussing the challenges and future directions for their clinical application as novel therapeutic agents in bone-related disorders, especially periodontitis. Despite promising in vitro and in vivo findings, clinical evidence remains limited, and further investigations are necessary to validate the efficacy, safety, and pharmacokinetics of tanshinones in human populations. Full article

Glehnia littoralis Fr. Schmidt ex Miq. has been cultivated in China for a long time and used as a medicinal plant called “Beishashen” in traditional Chinese medicine and has been traditionally known to have antibacterial and anti-inflammatory effects, but its direct role in periodontitis has not been known. Currently used periodontal treatments require long-term administration, which causes many side effects. Therefore, in this study, we evaluated the effects of G. littoralis extract (GLE) on periodontitis in an experimental periodontitis-induced in vitro and vivo model and understood its potential molecular mechanism. The effect of GLE on periodontitis in vitro was investigated using human periodontal ligament (HPDL) cells mediated by PG-LPS. Additionally, a ligature-induced periodontitis model and a PG-LPS-induced periodontal inflammation model were used to investigate the effect of GLE in vivo. In vitro study results showed that GLE down-regulated the increased inflammatory cytokines and mediators in HPDL cells stimulated with PG-LPS, and simultaneously down-regulated the levels of 11β-HSD1 and glucocorticoid receptor (GR), thereby alleviating periodontal inflammation. At the same time, it restored the lost osteoblast differentiation potential of HPDL cells. In addition, in an in vivo model representatively used for periodontitis research, the periodontal inflammation-alleviating effect and the effect of restoring or protecting damaged periodontal tissue were confirmed. GLE can be considered as a new periodontitis treatment agent through regulating 11β-HSD1. Full article

Bone is a preferred site for disseminated tumor cells, yet the molecular mechanisms that prepare the skeletal microenvironment for metastatic colonization are only beginning to be understood. At the heart of this process are extracellular vesicles (EVs), nano-sized, lipid-encapsulated particles secreted by cancer cells and stromal components. This review consolidates current findings that position EVs as key architects of the bone-metastatic niche. We detail the biogenesis of EVs and their organotropic distribution, focusing on how integrin patterns and bone-specific ligands guide vesicle homing to mineralized tissues. We then outline the sequential establishment of the pre-metastatic niche, driven by EV-mediated processes including fibronectin deposition, stromal cell reprogramming, angiogenesis, neurogenesis, metabolic reconfiguration, and immune modulation, specifically, the expansion of myeloid-derived suppressor cells and impaired lymphocyte function. Within the bone microenvironment, tumor-derived EVs carrying microRNAs and proteins shift the balance toward osteoclastogenesis, inhibit osteoblast differentiation, and disrupt osteocyte signaling. These alterations promote osteolytic destruction or aberrant bone formation depending on tumor type. We also highlight cutting-edge imaging modalities and single-EV omics technologies that resolve EV heterogeneity and identify potential biomarkers detectable in plasma and urine. Finally, we explore therapeutic approaches targeting EVs, such as inhibition of nSMase2 or Rab27A, extracorporeal EV clearance, and delivery of engineered, bone-targeted vesicles, while addressing translational challenges and regulatory considerations. This review offers a roadmap for leveraging EV biology in predicting, preventing, and treating skeletal metastases by integrating advances across basic biology, bioengineering, and translational science. Full article

Autophagy is a cellular process that recycles intracellular macromolecules and degrades toxic cytoplasmic material to provide the cell with nutrients and facilitate survival. Although autophagy and its role in the differentiation of osteoblasts, osteoclasts, and odontoblasts has been described, the importance of autophagy during matrix mineralization remains unaddressed. This review aims to characterize the autophagy/matrix mineralization relationship and elucidate the significance of autophagy during matrix mineralization. During the mineralization process, autophagy is important for cell survival and promotes the differentiation of osteoblasts and odontoblasts, the key cells that facilitate bone and dentin formation. Differentiation of these cells results in the synthesis of an organic proteinaceous matrix which subsequently forms the template for the deposition of calcium and phosphate to ultimately form crystalline hydroxyapatite. In bone, autophagy influences osteoblastic/osteoclastic activity and bone remodeling. In dentin, autophagy participates in odontogenic differentiation and facilitates odontoblastic secretion of dentin matrix proteins. This review aims to show that autophagy is critical for bone mineralization and tooth formation by supporting intracellular signaling pathways required for cell differentiation and subsequent matrix mineralization. Full article

Mechanical stresses affect a variety of cellular events in relation to the frequency, magnitude, and duration of the stimuli applied. Embryonic stem cell (ESC)-derived embryoid bodies (EBs) are pluripotent stem cell aggregates and comprise all somatic cells. Numerous studies have highlighted the effects of mechanosignals on stem cells, whereas their impact on EBs has been barely investigated. Here, we examined how cyclic tensile stress affects the behavior of EBs to differentiate into mineralized osteocytes by applying 2% elongation at 0.5 Hz frequency for 1 h once or 1 h every other day for 5 or 14 days in osteogenic medium. EBs that expressed undifferentiated markers, Oct4 and Sox2, were differentiated into mineralized cells, along with the accumulation of runt-related transcription factor 2 (RUNX2) and β-catenin in osteogenic medium. The application of tensile force inhibited EB’ mineralization via the downregulation of bone sialoprotein, osteocalcin, osterix, and RUNX2. While the transfection with si-β-catenin did not affect the osteogenic potency of EBs at a significant level, treatment with 10 μM of PD98059, but not of SP600125 or SB203580, diminished the mineralization of EBs and the expression of RUNX2 and RUNX2-regulated osteoblastic genes. The level of phosphorylated extracellular signal-regulated kinase-1 (p-ERK1) rather than p-ERK2 was more apparently diminished in tension-applied EBs. The transfection with si-ERK1, but not with si-ERK2, suppressed the mineralization of osteogenic medium-supplied EBs and the expression of osteoblast-specific genes. Collectively, this study demonstrates that tensile stress inhibits osteogenic potency of EBs by downregulating ERK1-mediated signaling and osteogenic gene expression. Full article

This study aimed to develop polylactic acid (PLA)-based membranes incorporating tramadol (TMD) using air jet spinning (AJS), ensuring stable physicochemical properties and biocompatibility. Two groups were fabricated: 10% PLA membranes (control) and 10% PLA membranes loaded with TMD in an 80:1 ratio (experimental). Characterization included scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-VIS), and biocompatibility assays with human osteoblasts using resazurin, crystal violet staining, and 5-chloromethylfluorescein diacetate for fluorescence microscopy. SEM revealed a homogeneous, randomly distributed fiber pattern, with diameters under 5 µm and no structural voids. DSC and TGA indicated that TMD was uniformly incorporated, increased the thermal capacity, and slightly lowered the onset and inflection degradation temperatures. FT-IR confirmed the chemical compatibility of TMD with PLA, showing no structural alterations. UV-VIS detected sustained TMD release over 72 h. Biocompatibility tests showed no cytotoxic effects; cell viability and proliferation in TMD-loaded membranes were comparable to controls. Statistical analysis used ANOVA and Wilcoxon tests. 10% PLA membranes loaded with TMD at an 80:1 ratio exhibited stable physicochemical characteristics and favorable biocompatibility, supporting their potential use in drug delivery systems. Full article