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Bone Jun 2024Tmem119 was identified as a bone anabolic factor in osteoblast, however the roles of Tmem119 on bone repair have remained unknown. Therefore, we herein investigated the...
Tmem119 was identified as a bone anabolic factor in osteoblast, however the roles of Tmem119 on bone repair have remained unknown. Therefore, we herein investigated the roles of Tmem119 on bone repair by examining the bone repair process after a femoral bone defect using Tmem119-deficient mice. In Tmem119-deficient mice, bone repair after a femoral bone defect was significantly delayed 10 and 14 days after bone injury in female and male mice with 3-dimensional micro-computed tomography analyses, respectively. The number of alkaline phosphatase-positive cells at the damaged sites was significantly decreased 7 days after bone injury in Tmem119-deficient mice, although the number of Osterix-positive cells was not significantly different 4 days after bone injury. The number of tartrate-resistant acid phosphatase-positive multinucleated cells as well as the number and luminal area of CD31-positive vessels at the damaged sites were not significantly different between Tmem119-deficient and wild-type mice. The present study first showed that Tmem119 deficiency delayed bone repair partly through a decrease in the osteoblastic bone formation of differentiated osteoblasts.
PubMed: 38942344
DOI: 10.1016/j.bone.2024.117177 -
Journal of Oral Biosciences Jun 2024This study aimed to elucidate whether the administration of parathyroid hormone (PTH) results in remodeling- or modeling-based bone formation in different regions of the...
Regional difference in the distribution of alkaline phosphatase, PHOSPHO1, and calcein labeling in the femoral metaphyseal trabeculae in parathyroid hormone-administered mice.
OBJECTIVES
This study aimed to elucidate whether the administration of parathyroid hormone (PTH) results in remodeling- or modeling-based bone formation in different regions of the murine femora, and whether the PTH-driven bone formation would facilitate osteoblastic differentiation into osteocytes.
METHODS
Six-week-old male C57BL/6J mice were employed to examine the distribution of alkaline phosphatase (ALP), PHOSPHO1, podoplanin, and calcein labeling in two distinct long bone regions: the metaphyseal trabeculae close to the chondro-osseous junction (COJ) and those distant from the COJ in three mouse groups, a control group receiving a vehicle (Sham group) and groups receiving hPTH (1-34) twice a day (PTH BID group) or four times a day (PTH QID group) for two weeks.
RESULTS
The Sham group showed PHOSPHO1-reactive mature osteoblasts localized primarily at the COJ, whereas the PTH BID/QID groups exhibited extended lines of PHOSPHO1-reactive osteoblasts even in regions distant from the COJ. The PTH QID group displayed fragmented calcein labeling in trabeculae close to the COJ, whereas continuous labeling was observed in trabeculae distant from the COJ. Osteoblasts tended to express podoplanin and PHOSPHO1 independently in the close and distant regions of the Sham group, while osteoblasts in the PTH-administered groups showed immunoreactivity of podoplanin and PHOSPHO1 together in the close and distant regions.
CONCLUSIONS
Administration of PTH may accelerate remodeling-based bone formation in regions close to the COJ while predominantly inducing modeling-based bone formation in distant regions. PTH appeared to simultaneously facilitate osteoblastic bone mineralization and differentiation into osteocytes in both remodeling- and modeling-based bone formation.
PubMed: 38942193
DOI: 10.1016/j.job.2024.06.007 -
International Journal of Pharmaceutics Jun 2024This paper focuses on the preparation and characterization of antibacterial alginate microparticles containing silver@hydroxyapatite functionalized calcium carbonate...
This paper focuses on the preparation and characterization of antibacterial alginate microparticles containing silver@hydroxyapatite functionalized calcium carbonate composites for tissue engineering. Microparticles were prepared by cross-linking a silver@composite sodium alginate dispersion with CaCl. This method showed a very good silver efficiency loading and the presence of silver chloride nanoparticles was detected. Silver free microparticles, containing hydroxyapatite functionalized calcium carbonates and neat alginate microparticles were prepared as well. All microparticles were characterized for water absorption and for in vitro bioactivity by immersion in simulated body fluid (SBF). Finally, antimicrobial and antibiofilm activities as well as cytotoxicity were evaluated. Microparticles containing silver@composites exhibited good antimicrobial and antibiofilm activities against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Candida albicans, but exerted a certain cytotoxicity against the tested cell models (fibroblasts and osteoblasts). Microparticles containing hydroxyapatite functionalized calcium carbonates were found to be always less cytotoxic, also in comparison to neat alginate microparticles, proving that the presence of the inorganic matrices exerts a protective effect on microparticle cytotoxicity.
PubMed: 38942183
DOI: 10.1016/j.ijpharm.2024.124393 -
Biomedicine & Pharmacotherapy =... Jun 2024In cell-based bone augmentation, transplanted cell dysfunction and apoptosis can occur due to oxidative stress caused by the overproduction of reactive oxygen species...
In cell-based bone augmentation, transplanted cell dysfunction and apoptosis can occur due to oxidative stress caused by the overproduction of reactive oxygen species (ROS). Edaravone (EDA) is a potent free radical scavenger with potential medical applications. This study aimed to investigate the effect of controlling oxidative stress on bone regeneration using EDA. Bone marrow-derived cells were collected from 4-week-old rats, and EDA effects on cell viability and osteogenic differentiation were evaluated. Collagen gels containing PKH26-prelabeled cells were implanted into the calvarial defects of 12-week-old rats, followed by daily subcutaneous injections of normal saline or 500 μM EDA for 4 d. Bone formation was examined using micro-computed tomography and histological staining. Immunofluorescence staining was performed for markers of oxidative stress, macrophages, osteogenesis, and angiogenesis. EDA suppressed ROS production and hydrogen peroxide-induced apoptosis, recovering cell viability and osteoblast differentiation. EDA treatment in vivo increased new bone formation. EDA induced the transition of the macrophage population toward the M2 phenotype. The EDA group also exhibited stronger immunofluorescence for vascular endothelial growth factor and CD31. In addition, more PKH26-positive and PKH26-osteocalcin-double-positive cells were observed in the EDA group, indicating that transplanted cell survival was prolonged, and they differentiated into bone-forming cells. This could be attributed to oxidative stress suppression at the transplantation site by EDA. Collectively, local administration using EDA facilitates bone regeneration by improving the local environment and angiogenesis, prolonging survival, and enhancing the osteogenic capabilities of transplanted cells.
PubMed: 38941894
DOI: 10.1016/j.biopha.2024.117032 -
Alternative Therapies in Health and... Jun 2024Osteoporosis (OP) is a chronic skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue, resulting in increased bone...
Study on the Mechanism of Xianling Gubao Capsule Regulating Runt-Related Transcription Factor 2 (RUNX2) and Promoting Osteoblast Differentiation by N6-Methyladenosine (m6A) Methyltransferase-Like 3 (METTL3).
BACKGROUND
Osteoporosis (OP) is a chronic skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue, resulting in increased bone fragility and a higher risk of fractures. It is a significant public health concern, particularly among postmenopausal women and older adults. The imbalance between bone formation and resorption is the fundamental cause of OP. Current clinical drugs for OP have limited efficacy and can cause side effects. Therefore, there is a need to explore alternative treatments and investigate their mechanisms to improve OP management. The Xianling Gubao capsule, a traditional Chinese medicine, is commonly used to treat OP by tonifying the kidney. However, the specific mechanism of action of the Xianling Gubao capsule in improving OP remains unclear, necessitating further research in this area.
METHODS
The N6-methyladenosine (m6A) content was evaluated by dot blot and m6A ribonucleic acid (RNA) methylation assay kit. The contents of methyltransferase-like 3 (METTL3), runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), and bone gamma-carboxyglutamate protein (BGLAP) were appraised by quantitative Reverse Transcription polymerase chain reaction (qRT-PCR) and western blot. The bilateral ovariectomy (OVX) method was used to establish an animal model of OP. OP bone marrow mesenchymal stem cells (OP-BMSCs) were extracted from mice in the OVX group by the whole bone marrow method. METTL3 overexpression and control vectors were transfected to OP-BMSCs using X-tremeGENE HP DNA Transfection Reagent. The ALP activity in OP-BMSCs was assessed by ALP staining. The calcium nodules in OP-BMSCs were detected by Alizarin Red S (ARS) assay. The Xianling Gubao capsule solution was employed to gavage mice, and the drug-containing serum was used to treat OP-BMSCs. Dot blot allows for the assessment of relative levels of m6A modification. The m6A RNA methylation assay kit is a specialized kit designed to quantitatively measure m6A levels in RNA samples. qRT-PCR allows for the measurement of mRNA levels of target genes. Western blot is used to detect and quantify specific proteins in a sample, and provides information about protein expression levels. OVX mimics the hormonal changes occurring in postmenopausal women and leads to bone loss and osteoporotic conditions in animals. This model allows for the investigation of the effects of the Xianling Gubao capsule on OP in a controlled experimental setting.
RESULTS
The m6A modification and METTL3, RUNX2, ALP, and BGLAP levels were reduced in bone samples of patients with OP and OVX mice compared with the corresponding control groups. Upregulated METTL3 enhanced the osteogenic ability of OP-BMSCs. METTL3 overexpression obviously increased m6A modification and METTL3, RUNX2, ALP, and BGLAP levels in OP-BMSCs. Xianling Gubao capsule treatment could weaken the impact of OP in mice by regulating the m6A modification and METTL3, RUNX2, ALP, and BGLAP levels. Serum containing Xianling Gubao capsule could enhance the osteogenic capability of OP-BMSCs and boost METTL3, RUNX2, ALP, and BGLAP levels. Treatment with the Xianling Gubao capsule shows promising effects in attenuating the impact of OP. The capsule is found to regulate m6A modification and increase the levels of METTL3, RUNX2, ALP, and BGLAP in OP-BMSCs. This indicates that the Xianling Gubao capsule may rescue the diminished osteogenic capability of OP-BMSCs by modulating METTL3. These findings suggest that the Xianling Gubao capsule has the potential to be an effective drug for the treatment of OP.
CONCLUSION
Taken together, the m6A modification and contents of osteogenic-related factors were reduced in OP. Upregulated METTL3 improved the osteogenic ability, m6A modification, and osteogenic-related factor abundances in OP-BMSCs. Xianling Gubao capsule rescued the diminished osteogenic capability of OP-BMSCs by modulating METTL3 and might serve as an effective drug for OP. The Xianling Gubao capsule, as a traditional Chinese medicine, could potentially complement existing therapeutic approaches for OP. By targeting the m6A modification pathway and promoting osteogenic differentiation, the capsule may help to expedite bone formation and repair, which are critical for managing OP and reducing the risk of fractures.
PubMed: 38940781
DOI: No ID Found -
International Journal of Molecular... Aug 2024The ubiquitin (Ub)‑proteasome system (UPS) plays a pivotal role in maintaining protein homeostasis and function to modulate various cellular processes including... (Review)
Review
The ubiquitin (Ub)‑proteasome system (UPS) plays a pivotal role in maintaining protein homeostasis and function to modulate various cellular processes including skeletal cell differentiation and bone homeostasis. The Ub ligase E3 promotes the transfer of Ub to the target protein, especially transcription factors, to regulate the proliferation, differentiation and survival of bone cells, as well as bone formation. In turn, the deubiquitinating enzyme removes Ub from modified substrate proteins to orchestrate bone remodeling. As a result of abnormal regulation of ubiquitination, bone cell differentiation exhibits disorder and then bone homeostasis is affected, consequently leading to osteoporosis. The present review discussed the role and mechanism of UPS in bone remodeling. However, the specific mechanism of UPS in the process of bone remodeling is still not fully understood and further research is required. The study of the mechanism of action of UPS can provide new ideas and methods for the prevention and treatment of osteoporosis. In addition, the most commonly used osteoporosis drugs that target ubiquitination processes in the clinic are discussed in the current review.
Topics: Humans; Osteoporosis; Ubiquitination; Animals; Ubiquitin; Proteasome Endopeptidase Complex; Bone Remodeling; Ubiquitin-Protein Ligases
PubMed: 38940355
DOI: 10.3892/ijmm.2024.5392 -
Frontiers in Pharmacology 2024Although caffeine generally offers benefits to human health, its impact on bone metabolism remains unclear. This study aimed to systematically evaluate the long-term...
Although caffeine generally offers benefits to human health, its impact on bone metabolism remains unclear. This study aimed to systematically evaluate the long-term effects of caffeine administration on osteoclasts, osteoblasts, and ovariectomy-induced postmenopausal osteoporosis (OP). Our findings revealed that 3.125 and 12.5 μg/mL caffeine inhibited RANKL-mediated osteoclastogenesis in RAW 264.7 cells through the MAPK and NF-κB pathways, accompanied by the inactivation of nuclear translocation of nuclear factor NFATc1. Similarly, 3.125 and 12.5 μg/mL of caffeine modulated MC3T3-E1 osteogenesis via the AKT, MAPK, and NF-κB pathways. However, 50 μg/mL of caffeine promoted the phosphorylation of IκBα, P65, JNK, P38, and AKT, followed by the activation of NFATc1 and the inactivation of Runx2 and Osterix, ultimately disrupting the balance between osteoblastogenesis and osteoclastogenesis. studies showed that gavage with 55.44 mg/kg caffeine inhibited osteoclastogenesis, promoted osteogenesis, and ameliorated bone loss in ovariectomized mice. Conversely, long-term intake of high-dose caffeine (110.88 mg/kg) disrupted osteogenesis activity and promoted osteoclastogenesis, thereby disturbing bone homeostasis. Collectively, these findings suggest that a moderate caffeine intake (approximately 400 mg in humans) can regulate bone homeostasis by influencing both osteoclasts and osteoblasts. However, long-term high-dose caffeine consumption (approximately 800 mg in humans) could have detrimental effects on the skeletal system.
PubMed: 38939843
DOI: 10.3389/fphar.2024.1405173 -
European Journal of Endocrinology Jun 2024Osteoanabolic agents are used as a first line treatment in patients at high fracture risk. The PTH receptor 1 (PTH1R) agonists teriparatide (TPTD) and abaloparatide...
Osteoanabolic agents are used as a first line treatment in patients at high fracture risk. The PTH receptor 1 (PTH1R) agonists teriparatide (TPTD) and abaloparatide (ABL) increase bone formation, bone mineral density (BMD), and bone strength by activating PTH receptors on osteoblasts. Romosozumab (ROMO), a humanized monoclonal antibody against sclerostin, dramatically but transiently stimulates bone formation and persistently reduces bone resorption. Osteoanabolic agents increase BMD and bone strength while being more effective than antiresorptives in reducing fracture risk in postmenopausal women. However, direct comparisons of the antifracture benefits of osteoanabolic therapies are limited. In a direct comparison of TPTD and ABL, the latter resulted in greater BMD increases at the hip. While no differences in vertebral or non-vertebral fracture risk were observed between the two drugs, ABL led to a greater reduction of major osteoporotic fractures. Adverse event profiles were similar between the two agents except for hypercalcemia, which occurred more often with TPTD. No direct comparisons of fracture risk reduction between ROMO and the PTH1R agonists exist. Individual studies have shown greater increases in BMD and bone strength with ROMO compared to TPTD in treatment-naïve women and in women previously treated with bisphosphonates. Some safety aspects, such as a history of tumor precluding the use of PTH1R agonists, and a history of major cardiovascular events precluding the use of ROMO, should also be considered when choosing between these agents. Lastly, convenience of administration, reimbursement by national health systems and length of clinical experience may influence patient choice.
PubMed: 38938063
DOI: 10.1093/ejendo/lvae076 -
Cell Biology International Jun 2024Type 2 diabetic osteoporosis (T2DOP) is a skeletal metabolic syndrome characterized by impaired bone remodeling due to type 2 diabetes mellitus, and there are drawbacks...
Type 2 diabetic osteoporosis (T2DOP) is a skeletal metabolic syndrome characterized by impaired bone remodeling due to type 2 diabetes mellitus, and there are drawbacks in the present treatment. Osteoking (OK) is widely used for treating fractures and femoral head necrosis. However, OK is seldom reported in the field of T2DOP, and its role and mechanism of action need to be elucidated. Consequently, this study investigated whether OK improves bone remodeling and the mechanisms of diabetes-induced injury. We used db/db mice as a T2DOP model and stimulated MC3T3-E1 cells (osteoblast cell line) with high glucose (HG, 50 mM) and advanced glycation end products (AGEs, 100 µg/mL), respectively. The effect of OK on T2DOP was assessed using a combined 3-point mechanical bending test, hematoxylin and eosin staining, and enzyme-linked immunosorbent assay. The effect of OK on enhancing MC3T3-E1 cell differentiation and mineralization under HG and AGEs conditions was assessed by an alkaline phosphatase activity assay and alizarin red S staining. The AGEs/insulin-like growth factor-1(IGF-1)/β-catenin/osteoprotegerin (OPG) pathway-associated protein levels were assayed by western blot analysis and immunohistochemical staining. We found that OK reduced hyperglycemia, attenuated bone damage, repaired bone remodeling, increased tibial and femoral IGF-1, β-catenin, and OPG expression, and decreased receptor activator of nuclear kappa B ligand and receptor activator of nuclear kappa B expression in db/db mice. Moreover, OK promoted the differentiation and mineralization of MC3T3-E1 cells under HG and AGEs conditions, respectively, and regulated the levels of AGEs/IGF-1/β-catenin/OPG pathway-associated proteins. In conclusion, our results suggest that OK may lower blood glucose, alleviate bone damage, and attenuate T2DOP, in part through activation of the AGEs/IGF-1/β-catenin/OPG pathway.
PubMed: 38937979
DOI: 10.1002/cbin.12215 -
Molecular Therapy : the Journal of the... Jun 2024Alveolar bone loss in elderly populations is highly prevalent and increases the risk of tooth loss, gum disease susceptibility, and facial deformity. Unfortunately,...
Alveolar bone loss in elderly populations is highly prevalent and increases the risk of tooth loss, gum disease susceptibility, and facial deformity. Unfortunately, there are very limited treatment options available. Here, we developed a bone-targeted gene therapy that reverses alveolar bone loss in patients with osteoporosis by targeting the adaptor protein Schnurri-3 (SHN3). SHN3 is a promising therapeutic target for alveolar bone regeneration, because SHN3 expression is elevated in human and mouse mandible tissues with osteoporosis while deletion of SHN3 in mice greatly increases alveolar bone and tooth dentin mass. We used a bone-targeted recombinant adeno-associated virus (rAAV) carrying an artificial microRNA (miRNA) that silences SHN3 expression to restore alveolar bone loss in mouse models of both postmenopausal and senile osteoporosis by enhancing WNT signaling and osteoblast function. Additionally, rAAV-mediated silencing of SHN3 enhanced bone formation and collagen production of human skeletal organoids in xenograft mice. Finally, rAAV expression in the mandible was tightly controlled via liver- and heart-specific miRNA-mediated repression or via a vibration-inducible mechanism. Collectively, our results demonstrate that AAV-based bone anabolic gene therapy is a promising strategy to treat alveolar bone loss in osteoporosis.
PubMed: 38937970
DOI: 10.1016/j.ymthe.2024.06.036