Osteoclast Activity Research Articles

Morphological characterization and transcriptome analysis of opercular deformity in golden pompano (Trachinotus ovatus)

Skeletal deformity is one of the major threats to aquaculture because of its negative effects in important economic losses. Recently, a high rate of opercular deformities was observed in farmed golden pompano (Trachinotus ovatus), which is a key species for marine cage culture in the South China Sea. In the present study, a structural, histological, and biochemical analysis of the deformed opercular complex in T. ovatus was carried out using micro-CT, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), paraffin section, and staining. A 3D reconstruction of the deformed and normal opercular complex has revealed an inward folding of both opercle and subopercle, and frequently affected branchiostegal rays being coated by the deformed opercle and subopercle. In addition, an increased Ca, P, and Mg content was identified in the deformed opercle. The Hematoxylin-eosin (HE) and tartrate resistant acid phosphatase (TRAP) staining of the deformed opercle have shown a higher osteoclast activity and increased bone resorption area. Further analyses on the difference of gene expression between the deformed and normal opercle have been performed using Illumina sequencing platform. As a result, a total of 1220 DEGs (including 508 up-regulated and 712 down-regulated genes) were identified. DEGs related to osteoblast and osteoclast differentiation revealed an important role of bone metabolism in opercular deformity. Moreover, GO and KEGG analysis of these DEGs showed that they were significantly enriched in functions and pathways related to muscle form, development and contraction. Additionally affected pathways including ion homeostasis suggested that functions of gills such as breathing and osmoregulation might be affected by the deformed opercle.

Titanium dioxide nanoparticles oral exposure induce osteoblast apoptosis, inhibit osteogenic ability and increase lipogenesis in mouse

Titanium dioxide nanoparticles (TiO2-NPs) are widely used in food, paint, coating, cosmetic, and composite orthodontic material. As a common food additive, TiO2-NPs can accumulate in various organs of human body, but the effect and underlying mechanism of bone remain unclear. Here mice were exposed to TiO2-NPs by oral gavage, and histological staining of femoral sections showed that TiO2-NPs reduced bone formation and enhanced osteoclast activity and lipogenesis, contributing to decreased trabecula bone. Transmission electron microscope (TEM) as well as biochemical and flow cytometry analysis of osteoblast exhibited that TiO2-NPs accumulated in osteoblast cytoplasm and impaired mitochondria ultrastructure with increased reactive oxygen species (ROS) and lipid hyperoxide, resulting in osteoblast apoptosis. In terms of mechanism, TiO2-NPs treatment inhibited expression of AKT and then increased pro-apoptotic protein Bax expression which was failure to form heterodimers with decreased anti-apoptotic Bcl-2, activating downstream Caspase-9 and Caspase-3 and inducing apoptosis. Additionally, TiO2-NPs suppressed Wnt3a level and then activated anti-Glycogen synthesis kinase (GSK-3β) phosphorylation, and ultimately resulted in degradation of β-catenin which down-regulated Runt-related transcription factor 2 (Runx2) and Osterix, inhibiting expression of osteogenic related proteins. Together, these results revealed that exposure of TiO2-NPs induced apoptosis and inhibited osteoblast differentiation through suppressing PI3K/AKT and Wnt/β-catenin signaling pathways, resulting in reduction of trabecula bone.

Angiopoietin 1 Relieves Osteolysis by Promoting Macrophage Mitophagy Through the TBK1-SQSTM1 Pathway to Inhibit AIM2 Inflammasome-Mediated Pyroptosis.

Osteolysis resulting from wear particles and subsequent aseptic loosening is a leading cause of revision surgery of artificial joints. The underlying pathogenesis of particle-induced osteolysis (PPO) has remained largely uncertain. Addressing how to mitigate osteolysis caused by wear particles presents a significant challenge for orthopedic surgeons. This study aimed to explore the molecular mechanism by which Angiopoietin (Ang-1) inhibits osteoclast activation to alleviate osteolysis. RAW264.7 mouse macrophages were stimulated with LPS or RANKL to induce osteoclast formation. Additionally, titanium (Ti) particles (50mg) were subperiosteally implanted around the cranial suture of mice to establish a calvarial osteolysis model. Ang-1, a member of the pro-angiogenic factor protein family and an important inflammatory regulator molecule, was utilized in this model. TRAP staining was utilized to detect osteoclast activation, while a western blot was conducted to identify key proteins associated with mitophagy and pyroptosis. Scanning electron microscopy was employed to observe the morphology and dimensions of Ti particles. Additionally, a combination of micro-CT, H&E, Masson's trichrome, and immunohistochemical staining techniques were applied to analyze the calvarial samples. Results indicated that Ang-1 could inhibit LPS- or RANKL-induced osteoclastogenesis and alleviate Ti particle-induced calvarial osteolysis in mice. TBK-1, a key signaling molecule involved in initiating mitophagy, was found to be mechanistically enhanced by Ang-1 through promoting TBK-1 phosphorylation in macrophages. This process inhibited AIM2 inflammasome-mediated pyroptosis and impeded osteoclastogenesis. Overall, this research uncovers a novel mechanism by which Ang-1 can attenuate inflammatory osteolysis, potentially offering a new therapeutic approach for PPO.

Patient-Reported Outcomes in Autosomal Dominant Osteopetrosis: Findings from the Osteopetrosis Registry Study.

Autosomal dominant osteopetrosis (ADO) is a rare sclerotic bone disease characterized by impaired osteoclast activity, resulting in high bone mineral density and skeletal fragility. The full phenotype and disease burden on patients' daily lives has not been systematically measured. We developed an online registry to ascertain population-based data on the spectrum and rate of progression of disease and to identify relevant patient centered outcomes that could be used to measure treatment effects and guide the design of future clinical trials. Cross-sectional data from participants with osteopetrosis were collected using an online REDCap-based database. Thirty-four participants with a confirmed diagnosis of ADO, aged 4-84 years. Participants aged 18 years and older completed the PROMIS 57, participants aged 8 to 17 years completed the PROMIS Pediatric 49, and parents of participants aged <18 years completed the PROMIS Parent Proxy 49. Based on the PROMIS 57, relative to the general population, adults with ADO reported low physical function and low ability to participate in social roles and activities, and high levels of anxiety, fatigue, sleep problems, and pain interference. Daily pain medications were reported by 24% of the adult population. In contrast, neither pediatric participants, nor their parent proxy reported a negative impact on health-related quality of life. Data from this registry demonstrate the broad spectrum of ADO disease severity and high impact on health-related quality of life in adults with ADO.

Suppression of bone resorption by Mori Radicis Cortex through NFATc1 and c-Fos signaling-mediated inhibition of osteoclast differentiation.

Mori Radicis Cortex (MRC) is the root bark of the mulberry family as Morus alba L. In Korea, it is known as "Sangbaegpi". Although MRC has demonstrated anti-inflammatory and antioxidant effects, its specific mechanisms of action and impact on osteoporosis remain poorly understood. To investigate the antiosteoporosis effect of MRC, we examined the level of osteoclast differentiation inhibition in receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced-RAW 264.7 cells and animal models of ovariectomy (OVX) with MRC. Serum analysis in OVX animals was investigated by enzyme-linked immunosorbent assay (ELISA), and bone density analysis was confirmed by micro-computed tomography (micro-CT). The expression analysis of nuclear factor of activated T cells 1 (NFATc1) was confirmed by immunohistochemistry (IHC) in femur tissue. In addition, osteoclast differentiation inhibition was measured using tartrate-resistant acid phosphatase (TRAP). mRNA analysis was performed using reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression analysis was investigated by western blot. Micro-CT analysis showed that MRC effectively inhibited bone loss in the OVX-induced rat model. MRC also inhibited the expression of alkaline phosphatase (ALP) and TRAP in serum. Histological analysis showed that MRC treatment increased bone density and IHC analysis showed that MRC significantly inhibited the expression of NFATc1. In RANKL-induced-RAW 264.7 cells, MRC significantly reduced TRAP activity and actin ring formation. In addition, MRC significantly inhibited the expression of NFATc1 and c-Fos, and suppressed the mRNA expression. Based on micro-CT, serum and histological analysis, MRC effectively inhibited bone loss in an OVX-induced rat model. In addition, MRC treatment suppressed the expression of osteoclast differentiation, fusion, and bone resorption markers through inhibition of NFATc1/c-Fos expression in RANKL-induced RAW 264.7 cells, ultimately resulting in a decrease in osteoclast activity. These results demonstrate that MRC is effective in preventing bone loss through inhibiting osteoclast differentiation and activity.

THE BENEFICIAL EFFECTS OF PROPOLIS ON OSTEOBLAST DIFFERENTIATION: A LITERATURE REVIEW

Introduction: Optimal bone regeneration is contingent upon the activities of osteoblasts, which are modulated by signalling molecules. Propolis, an abundantly beneficial natural substance, has the potential to induce the release of signalling molecules. Review: Four essential elements required for tissue regeneration via tissue engineering: scaffolds, signalling molecules, stem cells, and vascularization. Subsequently, osteoblast differentiation and activity are enhanced by signalling molecules induced by propolis. Propolis contains active ingredients that influence every stage of osteoblast differentiation. Propolis-induced increases in the release of signalling molecules (BMP, FGF, TGF) and the transcription factor RUNX2 stimulate the expression of diverse osteoblastogenic markers at each stage of differentiation: type I alpha 1 collagen during proliferation, alkaline phosphatase during maturation, and osteocalcin during mineralization. Conclusion: Propolis has the capacity to promote bone regeneration through its involvement in all phases of osteoblast differentiation (inducing the release of signalling molecules, increasing the transcription factor, and increasing the expression of osteoblastogenic markers). Additional research is required to determine how propolis influences the equilibrium between osteoblast and osteoclast activities in order to maintain optimal bone homeostasis and remodelling. The prolonged duration of bone regeneration necessitates the use of a carrier for propolis to remain on bone defects for an extended period of time.

6-O-angeloylplenolin inhibits osteoclastogenesis in vitro via suppressing c-Src/NF-κB/NFATc1 pathways and ameliorates bone resorption in collagen-induced arthritis mouse model

One of the effective therapeutic strategies to treat rheumatoid arthritis (RA)-related bone resorption is to target excessive activation of osteoclasts. We discovered that 6-O-angeloylplenolin (6-OAP), a pseudoguaianolide from Euphorbia thymifolia Linn widely used for the treatment of RA in traditional Chinese medicine, could inhibit RANKL-induced osteoclastogenesis and bone resorption in both RAW264.7 cells and BMMs from 1 μM and protect a collagen-induced arthritis (CIA) mouse model from bone destruction in vivo. The severity of arthritis and bone erosion observed in paw joints and the femurs of the CIA model were attenuated by 6-OAP administered at both dosages (1 or 5 mg/kg, i.g.). BMD, Tb.N and BV/TV were also improved by 6-OAP treatment. Histological analysis and TRAP staining of femurs further confirmed the protective effects of 6-OAP on bone erosion, which is mainly due to reduced osteoclasts. Molecular docking indicated that c-Src might be a target of 6-OAP and phosphorylation of c-Src was suppressed by 6-OAP treatment. CETSA and SPR assay further confirmed the potential interaction between 6-OAP and c-Src. Three signaling molecules downstream of c-Src that are vital to the differentiation and function of osteoclasts, NF-κB, c-Fos and NFATc1, were also suppressed by 6-OAP in vitro. In summary, the results demonstrated that the function of c-Src was disrupted by 6-OAP, which led to the suppression of downstream signaling vital to osteoclast differentiation and function. In conclusion, 6-OAP has the potential to be further developed for the treatment of RA-related bone erosion.

Chitosan modified with PAP as a promising delivery system for melatonin in the treatment of osteoporosis: targeting the divalent metal transporter 1.

The demands for novel and efficient therapies have gradually increased with the rising concerns of osteoporosis (OP). The most popular method in promoting bone regeneration during osteoporotic conditions consists of loading bioactive materials with different drugs to treat osteoporotic bones by either promoting the process of osteogenesis, or by inhibiting the activity of osteoclasts. By analyzing single cell sequencing results, we found that divalent metal transporter 1 (DMT1) played a role in OP. Based on our previous results, we found that melatonin (MT) suppressed expression of DMT1 induced by high glucose during OP, so we determined the efficacy of MT for the treatment of OP. However, the clinical effects of MT on OP were unsatisfactory. To enhance its biological efficacy, we combined MT with porous gelatin chitosan (chitosan) and the conductive material, PLA-b-AP-b-PLA (PAP), then determined how MT incorporation in chitosan@PAP nanoparticles affected the ability to promote MC3T3-E1 osteogenesis and mineralization, both in vitro and in vivo. The results confirmed the effect of MT on DMT1. We then prepared and characterized composites prepared as nanofibers, and determined the efficacy of MT combined with chitosan-PAP modified hydrogels as a slow-release system in a femur model of osteoporosis mice, with associated properties suitable for bone tissue engineering. The results indicated that MT-loaded chitosan@PAP nanospheres showed favorable osteogenic functions, both in vivo and in vitro, providing a practical solution for bone regeneration for OP patients.

Isobavachin attenuates osteoclastogenesis and periodontitis-induced bone loss by inhibiting cellular iron accumulation and mitochondrial biogenesis

As bone-resorbing cells rich in mitochondria, osteoclasts require high iron uptake to promote mitochondrial biogenesis and maintain a high-energy metabolic state for active bone resorption. Given that abnormal osteoclast formation and activation leads to imbalanced bone remodeling and osteolytic bone loss, osteoclasts may be crucial targets for treating osteolytic diseases such as periodontitis. Isobavachin (IBA), a natural flavonoid compound, has been confirmed to be an inhibitor of receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation from bone marrow-derived macrophages (BMMs). However, its effects on periodontitis-induced bone loss and the potential mechanism of its anti-osteoclastogenesis effect remain unclear. Our study demonstrated that IBA suppressed RANKL-induced osteoclastogenesis in BMMs and RAW264.7 cells and inhibited osteoclast-mediated bone resorption in vitro. Transcriptomic analysis indicated that iron homeostasis and reactive oxygen species (ROS) metabolic process were enriched among the differentially expressed genes following IBA treatment. IBA exerted its anti-osteoclastogenesis effect by inhibiting iron accumulation in osteoclasts. Mechanistically, IBA attenuated iron accumulation in RANKL-induced osteoclasts by inhibiting the mitogen-activated protein kinase (MAPK) pathway to upregulate ferroportin1 (Fpn1) expression and promote Fpn1-mediated intracellular iron efflux. We also found that IBA inhibited mitochondrial biogenesis and function, and reduced RANKL-induced ROS generation in osteoclasts. Furthermore, IBA attenuated periodontitis-induced bone loss by reducing osteoclastogenesis in vivo. Overall, these results suggest that IBA may serve as a promising therapeutic strategy for bone diseases characterized by osteoclastic bone resorption.

A bone adhesive enhances osteoporotic fracture repair by regulating bone homeostasis

Patients suffering from osteoporotic fractures often require effective fixation and subsequent bone repair. However, the currently available materials are functionally limited and often fail to improve outcomes in this patient population. In this study, we developed orthopedic adhesives doped with romosozumab-loaded mesoporous bioactive glass nanoparticles to aid in osteoporotic fracture fixation and restore dysregulated bone homeostasis. These adhesives were designed to promote osteoblast formation while simultaneously inhibiting osteoclastic bone-resorbing activity, thus working synergistically to promote the healing of osteoporotic fractures. Orthopedic adhesives exhibit injectability, reversible adhesiveness, and malleability, enhancing their adaptability to complex clinical scenarios. Furthermore, the release of romosozumab from mesoporous bioactive glass nanoparticles accelerated osteogenesis and inhibited osteoclastogenesis, delaying the bone resorption process. This dual action contributes to the regulation of bone regeneration and remodeling. Notably, our orthopedic adhesive could restore the disrupted bone homeostasis associated with osteoporotic fractures.

A 70% Ethanol Neorhodomela munita Extract Attenuates RANKL-Induced Osteoclast Activation and H2O2-Induced Osteoblast Apoptosis In Vitro.

The rapid aging of the population worldwide presents a significant social and economic challenge, particularly due to osteoporotic fractures, primarily resulting from an imbalance between osteoclast-mediated bone resorption and osteoblast-mediated bone formation. While conventional therapies offer benefits, they also present limitations and a range of adverse effects. This study explores the protective impact of Neorhodomela munita ethanol extract (EN) on osteoporosis by modulating critical pathways in osteoclastogenesis and apoptosis. Raw264.7 cells and Saos-2 cells were used for in vitro osteoclast and osteoblast models, respectively. By utilizing various in vitro methods to detect osteoclast differentiation/activation and osteoblast death, it was demonstrated that the EN's potential to inhibit RANKL induced osteoclast formation and activation by targeting the MAPKs-NFATc1/c-Fos pathway and reducing H2O2-induced cell death through the downregulation of apoptotic signals. This study highlights the potential benefits of EN for osteoporosis and suggests that EN is a promising natural alternative to traditional treatments.

Hydroxypropyl methylcellulose/sodium alginate/hydroxyapatite nano biomaterial enriched with zinc to promote bone tissue augmentation

Bone is a dynamic connective tissue that provides structural support and locomotion to human physiology. Severe bone degeneration can occur in cases of trauma, infections, genetic disorders, tumors, and hormonal imbalances. This leads to a demand for scaffolds and composites to enhance bone tissue regeneration. The present study aimed to develop a composite material using hydroxypropyl methylcellulose and sodium alginate in combination with hydroxyapatite. The composite was doped with zinc and developed into a nanocomposite using ionic gelation and solvent precipitation methods. The prepared nanocomposite was characterized by scanning electron microscopy, atomic force microscopy, dynamic light scattering, FTIR, and XRD studies. In vivo pharmacological studies were conducted to establish the bone targeting and bone tissue regeneration efficacy of the developed nanocomposite. The nanocomposite was checked for cell toxicity by performing an MTT assay using MG63 cell line and the molecular mechanism of targeting efficiency was assessed by an in silico evaluation method. The results of the study confirmed the polymeric interlinking in the nanocomposite and the successful preparation of a composite material using biodegradable excipients. SEM and AFM studies indicated that the nanocomposite was within the 80–200 nm size range. MTT assay indicated that the developed nanocomposite was not cytotoxic and well tolerated by the MG63 cell line. In vivo, studies in validation with molecular docking evaluation suggested that the nanocomposite was effectively targeted to the bone and enhanced the bone density by blocking Farnesyl Diphosphate Synthetase (FDPS) in the mevalonate pathway which is essential for inhibiting the osteoclastic activity and promoting osteogenesis.

Akkermansia muciniphila Promotes Bone Development and Improves Eggshell Quality during the Sexual Maturity Period of Laying Hens by Increasing Osteogenesis

Adequate bone development is imperative for maintaining the health and productivity of laying hens. Probiotics play a pivotal role in promoting bone formation and preventing osteoporosis. This study aimed to explore the effect of Akkermansia muciniphila (Akk) on the bone development and eggshell quality of laying hens during the rearing period. A total of 300 1-day-old Jingfen NO. 6 commercial pullets were categorized into two groups, one of which was fed a conventional diet for 20 weeks (Control group), the other group was fed a conventional diet with lyophilized Akk powder for 20 weeks (Akk group). During the first two weeks, pullets in the Akk group received live Akk inoculation, while birds in the Control group received normal saline administration. Micro-computed tomography analysis was employed to evaluate three bone microarchitectures: cortical bone (Cb), trabecular bone (Tb), and medullary bone (Mb). Our findings revealed that supplementation with Akk powder increased the thickness and bone mineral content of Cb and Tb, while simultaneously reducing the volume and bone surface area of Mb. The increased activity of alkaline phosphatase, a marker of osteogenesis, and the decreased activity of tartrate-resistant acid phosphatase, a marker of osteoclastic activity, were observed in the Akk group. Dietary supplementation of Akk powder improved the immune microenvironment in the bone marrow by increasing osteogenic-related CD8+ T cells and decreasing osteoclastogenesis-related CD4+ T cells. Additionally, Akk powder supplementation significantly enriched the Lactobacillaceae family in cecum. The enhancement of bone development by Akk contributed to increased eggshell strength and thickness. These findings demonstrate the osteomodulatory effects of Akk in laying hens and the connections between bone physiology and eggshell quality, highlighting the importance of gut–bone communications in laying hens.

Modulatory interactions of T-2 and deoxynivalenol mycotoxins on murine femoral development and osteological integrity

In this study, we conducted a systematic assessment of the effectsof deoxynivalenol (DON) and T-2 mycotoxins (T-2) on the developmental processes and structural integrity of murine femurs, considering both the isolated and synergistic effects of these toxins. To this end, we divided 72 male mice into nine groups, each subjected to varying dosages of T-2, DON, or their combinations. Over a four-week experimental period, meticulous monitoring was undertaken regarding the mice's body weight, biochemical markers of bone formation and resorption, and the activity of relevant cells. To comprehensively evaluate alterations in bone structure, we employed biomechanical analysis, micro-computed tomography (micro-CT), and transmission electron microscopy.Our findings unveiled a significant revelation: the mice exhibited a dose-dependent decrease in body weight upon exposure to individual mycotoxins, while the combined use of these toxins manifested an atypical antagonistic effect. Furthermore, we observed variations in the levels of calcium, phosphorus, and vitamin D, as well as adjustments in the activities of osteoblasts and osteoclasts, all intricately linked to the dosage and ratio of the toxins. Alterations in biomechanical properties were also noted to correlate with the dosage and combination of toxins. Analyses via micro-CT and transmission electron microscopy further corroborated the substantial impact of toxin dosage and combinations on both cortical and trabecular bone structures.In summation, our research unequivocally demonstrates the dose- and ratio-dependent detrimental effects of DON and T-2 mycotoxins on the growth and structural integrity of murine femurs. These insights accentuate the importance of a profound understanding of the potential risks these toxins pose to bone health, offering pivotal guidance for future toxicological research and public health preventative strategies.

The Effects of Local Treatment of PTH(1-34) and Whitlockite and Hydroxyapatite Graft to the Calvarial Defect in a Rat Osteoporosis Model.

With the aging population, there is a rising incidence of senile diseases, notably osteoporosis, marked by fractures, prolonged recovery, and elevated mortality rates, underscoring the urgency for effective treatments. In this study, we applied the method of absorbing parathyroid hormone (PTH), a treatment for osteoporosis, into graft materials. Two types of graft materials with different properties, whitlockite (WH) and hydroxyapatite (HAP), were used. After forming calvarial defects in osteoporotic rats, WH and HAP grafts were implanted, with PTH applied directly to the graft sites. Micro-CT analysis was employed to assess bone regeneration, while tissue sections were stained to elucidate the regeneration process and bone cell dynamics. The results showed that bone regeneration was higher in the grafts that were actively degraded by osteoclasts in the early stage of regeneration. When PTH was applied, osteoclast activity increased, leading to enhanced bone regeneration. Furthermore, the activation of osteoclasts resulted in the penetration and formation of new bone within the degraded graft, which exhibited higher osseointegration. Therefore, for osteoporotic bone defects, bone grafts that can be easily degraded by osteoclasts are more suitable. Additionally, treatment with PTH can activate osteoclasts around the bone graft in the early stages of regeneration, inducing higher bone regeneration and improving osseointegration.

Smart osteoclasts targeted nanomedicine based on amorphous CaCO3 for effective osteoporosis reversal

BackgroundOsteoporosis is characterized by an imbalance in bone homeostasis, resulting in the excessive dissolution of bone minerals due to the acidified microenvironment mediated by overactive osteoclasts. Oroxylin A (ORO), a natural flavonoid, has shown potential in reversing osteoporosis by inhibiting osteoclast-mediated bone resorption. The limited water solubility and lack of targeting specificity hinder the effective accumulation of Oroxylin A within the pathological environment of osteoporosis.ResultsOsteoclasts’ microenvironment-responsive nanoparticles are prepared by incorporating Oroxylin A with amorphous calcium carbonate (ACC) and coated with glutamic acid hexapeptide-modified phospholipids, aiming at reinforcing the drug delivery efficiency as well as therapeutic effect. The obtained smart nanoparticles, coined as OAPLG, could instantly neutralize acid and release Oroxylin A in the extracellular microenvironment of osteoclasts. The combination of Oroxylin A and ACC synergistically inhibits osteoclast formation and activity, leading to a significant reversal of systemic bone loss in the ovariectomized mice model.ConclusionThe work highlights an intelligent nanoplatform based on ACC for spatiotemporally controlled release of lipophilic drugs, and illustrates prominent therapeutic promise against osteoporosis.

Equisetum arvense standardized dried extract hinders age-related osteosarcopenia

Age-associated osteosarcopenia is an unresolved syndrome characterized by the concomitant loss of bone (osteopenia) and skeletal muscle (sarcopenia) tissues increasing falls, immobility, morbidity, and mortality. Unbalanced resorption of bone in the remodeling process and excessive protein breakdown, especially fast type II myosin heavy chain (MyHC-II) isoform and myofiber metabolic shift, are the leading causes of bone and muscle deterioration in the elderly, respectively. Equisetum arvense (EQ) is a plant traditionally recommended for many pathological conditions due to its anti-inflammatory properties. Thus, considering that a chronic low-grade inflammatory state predisposes to both osteoporosis and sarcopenia, we tested a standardized hydroalcoholic extract of EQ in in vitro models of muscle atrophy [C2C12 myotubes treated with proinflammatory cytokines (TNFα/IFNγ), excess glucocorticoids (dexamethasone), or the osteokine, receptor activator of nuclear factor kappa-B ligand (RANKL)] and osteoclastogenesis (RAW 264.7 cells treated with RANKL). We found that EQ counteracted myotube atrophy, blunting the activity of several pathways depending on the applied stimulus, and reduced osteoclast formation and activity. By in silico target fishing, IKKB-dependent nuclear factor kappa-B (NF-κB) inhibition emerges as a potential common mechanism underlying EQ′s anti-atrophic effects. Consumption of EQ (500 mg/kg/day) by pre-geriatric C57BL/6 mice for 3 months translated into: i) maintenance of muscle mass and performance; ii) restrained myofiber oxidative shift; iii) slowed down age-related modifications in osteoporotic bone, significantly preserving trabecular connectivity density; iv) reduced muscle- and spleen-related inflammation. EQ can preserve muscle functionality and bone remodeling during aging, potentially valuable as a natural treatment for osteosarcopenia.

Small extracellular vesicles derived from lipopolysaccharide-preconditioned dental follicle cells inhibit cell apoptosis and alveolar bone loss in periodontitis

ObjectiveThis study aimed to explore the effects of small extracellular vesicles derived from lipopolysaccharide-preconditioned dental follicle cells (L-D-sEV) on periodontal ligament cells from periodontitis affected teeth (p-PDLCs) in vitro and experimental periodontitis in mice. DesignIn vitro, the biological function of p-PDLCs and the underlying molecular mechanism were investigated by flow cytometry, Western blot, and quantitative real-time PCR (qRT-PCR) analysis. Eighteen-eight-week-old male C57BL/6 mice were randomly divided into three groups: control (Con), periodontitis (Peri), and L-D-sEV groups. Mice periodontitis model was induced by placing the 5–0 silk thread (around the maxillary second molar) and P.gingivalis (1 ×107 CFUs per mouse). In vivo, the alveolar bone loss, osteoclast activity, and macrophage polarization were measured by micro-computed tomography and histological analysis. ResultsIn vitro, the RANKL/OPG ratio and phosphorylation of JNK and P38 protein levels of p-PDLCs were significantly decreased after L-D-sEV administration. Besides, flow cytometry and qRT-PCR analysis showed that L-D-sEV reduced apoptosis of p-PDLCs, down-regulated apoptosis-related genes Caspase-3 and BCL-2-Associated X expression, and up-regulated B-cell lymphoma-2 gene levels. In vivo, L-D-sEV administration significantly reduced alveolar bone loss, inhibited osteoclast activity, and induced M2 polarization. The histological analysis showed that iNOS/CD206, RANKL/OPG, p-JNK/JNK, and p-P38/P38 ratios were significantly lower in the L-D-sEV group than in the Peri group. ConclusionsL-D-sEV administration alleviated alveolar bone loss by mediating RANKL/OPG-related osteoclast activity and M2 macrophage polarization, alleviating p-PDLCs apoptosis and proliferation via the JNK and P38 pathways.

Cinnamaldehyde attenuates streptozocin-induced diabetic osteoporosis in a rat model by modulating netrin-1/DCC-UNC5B signal transduction.

Background: Cinnamaldehyde (CMD) is a major functional component of Cinnamomum verum and has shown treatment effects against diverse bone diseases. This study aimed to assess the anti-diabetic osteoporosis (DOP) potential of diabetes mellitus (DM) and to explore the underlying mechanism driving the activity of CMD. Methods: A DOP model was induced via an intraperitoneal injection of streptozocin (STZ) into Sprague-Dawley rats, and then two different doses of CMD were administered to the rats. The effects of CMD on the strength, remodeling activity, and histological structure of the bones were assessed. Changes in the netrin-1 related pathways also were detected to elucidate the mechanism of the anti-DOP activity by CMD. Results: CMD had no significant effect on the body weight or blood glucose level of the model rats. However, the data showed that CMD improved the bone strength and bone remodeling activity as well as attenuating the bone structure destruction in the DOP rats in a dose-dependent manner. The expression of netrin-1, DCC, UNC5B, RANKL, and OPG was suppressed, while the expression of TGF-β1, cathepsin K, TRAP, and RANK was induced by the STZ injection. CMD administration restored the expression of all of these indicators at both the mRNA and protein levels, indicating that the osteoclast activity was inhibited by CMD. Conclusion: The current study demonstrated that CMD effectively attenuated bone impairments associated with DM in a STZ-induced DOP rat model, and the anti-DOP effects of CMD were associated with the modulation of netrin-1/DCC/UNC5B signal transduction.

Increased Circulating CD14+ Monocytes in Patients with Psoriatic Arthritis Presenting Impaired Apoptosis Activity.

Psoriatic arthritis (PsA) is a chronic inflammatory arthritis primarily affecting peripheral and axial joints. The osteolytic effect in the damaged joint is mediated by osteoclast activation. We aimed to investigate differential gene expression in peripheral CD14+ monocytes between patients with psoriatic arthritis (n = 15) and healthy controls (HCs; n = 15). Circulating CD14+ monocytes were isolated from peripheral blood mononuclear cells using CD14+ magnetic beads. Cell apoptosis was measured via Annexin V using flow cytometry. The gene expression profiling was analyzed via microarray (available in the NCBI GEO database; accession number GSE261765), and the candidate genes were validated using PCR. The results showed a higher number of peripheral CD14+ monocytes in patients with PsA than in the HCs. By analyzing the microarray data, identifying the differentially expressed genes, and conducting pathway enrichment analysis, we found that the apoptosis signaling pathway in CD14+ cells was significantly impaired in patients with PsA compared to the HCs. Among the candidate genes in the apoptotic signaling pathway, the relative expression level of cathepsin L was confirmed to be significantly lower in the PsAs than in the HCs. We concluded that the numbers of peripheral CD14+ monocytes increased, and their apoptosis activity was impaired in patients with PsA, which could lead to enhanced macrophage maturation and osteoclast activation. The resistance of apoptotic death in peripheral CD14+ monocytes may contribute to active joint inflammation in PsA.