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Background: Senile osteoporosis (SOP) is an age-related metabolic bone disease that currently lacks specific therapeutic interventions. Thus, this study aimed to investigate the effect of Astragaloside IV (AS-IV) on macrophage senescence, bone marrow mesenchymal stem cell (BMSC) osteogenesis, and SOP progression., Methods: A senescent macrophage model was established and treated with varying concentrations of AS-IV. Cell activity was measured using the CCK8 assay. The senescence levels of macrophages were evaluated through β-galactosidase staining, PCR, and immunofluorescence. Macrophage mitochondrial function was assessed using ROS and JC-1 staining. Macrophage polarization was evaluated through PCR, Western blot, and immunofluorescence. The inhibitory effects of AS-IV on macrophage senescence were investigated using Western blot analysis. Furthermore, the effects of macrophage conditioned medium (CM) on BMSCs osteogenic were detected using ALP, alizarin red, and PCR., Results: AS-IV inhibited macrophage senescence and M1 polarization, alleviated mitochondrial dysfunction, and promoted M2 polarization. Mechanistically, it suppressed the STING/NF-κB pathway in H2O2-activated macrophages. Conversely, the STING agonist c-di-GMP reversed the effects of AS-IV on macrophage senescence. Additionally, AS-IV-induced macrophage CM promoted BMSC osteogenic differentiation. In vivo, AS-IV treatment ameliorated aberrant bone microstructure and bone mass loss in the SOP mouse model, inhibited macrophage senescence, and promoted M2 polarization., Conclusions: By modulating the STING/NF-κB signaling pathway, AS-IV potentially inhibited macrophage senescence and stimulated osteogenic differentiation of BMSCs, thus exerting an anti-osteoporotic effect. Consequently, AS-IV may serve as an effective therapeutic candidate for the treatment of osteoporosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Mitochondria plays a role in cell differentiation and apoptosis processes. Maintaining mitochondrial function is critical, and this involves various aspects of mitochondrial quality control such as protein homeostasis, biogenesis, dynamics, and mitophagy. Osteoporosis, a metabolic bone disorder, primarily arises from two factors: the dysregulation between lipogenic and osteogenic differentiation of aging bone marrow mesenchymal stem cells, and the imbalance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Mitochondrial quality control has the potential to mitigate or even reverse the effects. Among the Sirtuin family, consisting of seven Sirtuins (SIRT1-7), SIRT1-SIRT6 play a crucial role in maintaining mitochondrial quality control. Additionally, SIRT1, SIRT3, SIRT6, and SIRT7 are directly involved in normal bone development and homeostasis by modulating bone cells. However, the precise mechanism by which these Sirtuins exert their effects remains unclear. This article reviews the impact of various aspects of mitochondrial quality control on osteoporosis, focusing on how SIRT1, SIRT3, and SIRT6 can improve osteoporosis by regulating mitochondrial protein homeostasis, biogenesis, and mitophagy. Furthermore, we provide an overview of the current state of clinical and preclinical drugs that can activate Sirtuins to improve osteoporosis. Specific Sirtuin-activating compounds are effective, but further studies are needed. The findings of this study may offer valuable insights for future research on osteoporosis and the development of clinical prevention and therapeutic target strategies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhang, Wang, Duan, Niu, Li, Yun, Sun, Ma and Guo.)

Background: Osteoporosis is a systemic bone disease characterized by decreased bone density and quality, destruction of bone microstructure, and increased bone fragility. Extracellular vesicles are lipid bilayer nanoparticles that participate in intercellular communication. Extracellular vesicles are becoming popular in the study of osteoporosis and the bone cell microenvironment. Extracellular vesicles can transmit cell signals and regulate bone homeostasis. Our previous studies revealed that the Chinese herbal medicine Guilu Erxian Glue promotes type I collagen synthesis and osteoprotegerin secretion by osteoblasts in rats, reverses the imbalance of bone homeostasis, and alleviates osteoporosis., Objective: We investigated how osteoblast-derived extracellular vesicles treated with Guilu Erxian Glue affected osteoclasts in vitro., Methods: We quantified osteoclast differentiation of RAW 264.7 using TRAP staining, cell apoptosis using flow cytometry, extracellular vesicle uptake by fluorescence tracing, bone absorption functions by bone resorption lacuna , and transcription of key genes by quantitative real-time PCR., Results: Fluorescently labeled mouse preosteoblastic MC3T3-E1 cells secreted nanoscale substances less than 1 μm in diameter. Mouse macrophage RAW 264.7 cells adsorbed these nanoparticles and PKH26-labeled extracellular vesicles derived from MC3T3-E1 cells on the cell membrane surface. Extracellular vesicles from MC3T3-E1 cells treated with Guilu Erxian Glue inhibited the differentiation of osteoclasts induced by receptor activator of nuclear factor-κB ligand and macrophage colony-stimulating factor and reduced the number of lacunae formed by osteoclasts in vitro compared with controls. Extracellular vesicles from MC3T3-E1 cells treated with Guilu Erxian Glue downregulated the relative messenger RNA expression of c-Fos, cathepsin K, nuclear factor of activated T cells 1, and tartrate-resistant acid phosphatase in osteoclasts, which may be part of the mechanism by which they regulate osteoclasts., Conclusions: Our results demonstrate that extracellular vesicles are essential for signal exchange between osteoblasts and osteoclasts. Although we do not know how Guilu Erxian Glue affects the signaling molecules carried by extracellular vesicles, we have shown for the first time, to our knowledge, that Guilu Erxian Glue can inhibit osteoclast differentiation and function via osteoblast-derived extracellular vesicles. Our findings are conducive to providing a new target for the development of osteoporosis drugs.

Quercetin, a flavonoid found in natural medicines, has shown a role in disease prevention and health promotion. Moreover, because of its recently identified contribution in regulating bone homeostasis, quercetin may be considered a promising agent for improving bone health.   This study aimed to elucidate the role of quercetin in androgen deprivation therapy-induced osteoporosis in mice. C57BL/6 mice were subjected to orchiectomy, followed by quercetin treatment (75 and 150 mg/kg/d) for 8 weeks. Bone microstructure was then assessed by micro-computed tomography, and a three-point bending test was used to evaluate the biomechanical parameters. Hematoxylin and eosin (H&E) staining was used to examine the shape of the distal femur, gastrocnemius muscle, and liver. The balance motion ability in mice was evaluated by gait analysis, and changes in the gastrocnemius muscle were observed via Oil red O and Masson's staining. ELISA and biochemical analyses were used to assess markers of the bone, glucose, and lipid metabolism. Western blotting analyses of glucose and lipid metabolism-related protein expression was performed, and expression of the GPCR6A/AMPK/mTOR signaling pathway-related proteins was also assessed. After 8 weeks of quercetin intervention, quercetin-treated mice showed increased bone mass, bone strength, and improved bone microstructure. Additionally, gait analysis, including stride length and frequency, were significantly increased, whereas a reduction of the stride length and gait symmetry was observed. H&E staining of the gastrocnemius muscle showed that the cross-sectional area of the myofibers had increased significantly, suggesting that quercetin improves balance, motion ability, and muscle mass. Bone metabolism improvement was defined by a reduction of serum levels of insulin, triglycerides, total cholesterol, and low-density lipoprotein, whereas levels of insulin-like growth factor-1 and high-density lipoprotein were increased after quercetin treatment. Expression of proteins involved in glucose uptake was increased, whereas that of proteins involved in lipid production was decreased. Moreover, the GPRC6A and the phospho-AMPK/AMPK expression ratio was elevated in the liver and tibia tissues. In contrast, the phospho-mTOR/mTOR ratio was reduced in the quercetin group. Our findings indicate that quercetin can reduce the osteoporosis induced by testosterone deficiency, and its beneficial effects might be associated with the regulation of glucose metabolism and inhibition of lipid metabolism via the GPCR6A/AMPK/mTOR signaling pathway., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sun, Pan, Li, Wang, Liu, Tu, Wu, Xiao, Han, Da, Ma and Guo.)

Introduction: The occurrence of osteoporosis (OP) has drawn considerable attention from scholars around the world due to the significant impacts thereof on the social economy and the quality of human life. OP research has been rapidly expanding since the inclusion of microRNAs (miRNAs) as critical regulators of gene-expression. However, despite the ability to evaluate miRNA gene therapy in OP being enhanced, there has been a scarcity of updated citation analyses that reflect such developments. In the present study, through bibliometric analysis, the global research activity and trends in regard to the relationship between OP and miRNAs were reviewed., Methods: Publications related to miRNA and OP from 2000 to 2021 were retrieved via Web of Science (WoS). The data included publication years, countries, journals, institutions, authors and keywords, and were sorted and summarized by bibliometrics, before being visually analyzed through VOS Viewer., Results: In the past five years, 599 articles have been published, with said studies accounting for 79.11% of all relevant documents, indicating the increased interest in the present research topic. The country with the highest contribution rate was China, and the publication rate of Journal of Bone and Mineral Research was the highest, followed by Bone. The institutions with the highest contribution rate were Nanjing Medical University. The most frequently occurring keywords were clustered into five groups. The research area of the first group described that circulating miRNA would be a potential biomarker for postmenopausal osteoporosis (PMOP). The remaining four groups involved the influences of miRNAs and exosomes on the osteogenic and adipogenic differentiation of mesenchymal stem cells (MSCs), and the interactions of lncRNA and miRNA with OP., Conclusions: The results of the present study will expand the research on miRNAs and OP. The research direction with the highest frequency was the miRNAs acting on osteoblasts and osteoclasts. The influence of miRNAs carried by exosomes on the differentiation of MSCs might become an effective method for OP cell-free treatment.

Osthole (OST), a derivative of Fructus Cnidii, has been proved to have potential anti-osteoporosis effects in our recent studies. However, its pharmacological effects are limited in the human body because of poor solubility and bioavailability. Under the guidance of the classical theory of Chinese medicine, Osthole-loaded N-octyl-O-sulfonyl chitosan micelles (NSC-OST), which has not previously been reported in the literature, was synthesized in order to overcome the defects and obtain better efficacy. In this study, we found that NSC-OST inhibited on the formation and resorption activity of osteoclasts through using a bone marrow macrophage (BMM)-derived osteoclast culture system in vitro, rather than affecting the viability of cells. We also found that NSC-OST inhibited osteoclast formation, hydroxyapatite resorption and RANKL-induced osteoclast marker protein expression. In terms of mechanism, NSC-OST suppressed the NFATc1 transcriptional activity and the activation of NF-κB signalling pathway. In vivo, ovariectomized (OVX) rat models were established for further research. We found that NSC-OST can attenuate bone loss in OVX rats through inhibiting osteoclastogenesis. Consistent with our hypothesis, NSC-OST is more effective than OST in parts of the results. Taken together, our findings suggest that NSC-OST can suppress RANKL-induced osteoclastogenesis and prevents ovariectomy-induced bone loss in rats and could be considered a safe and more effective anti-osteoporosis drug than OST., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Wen-Shen-Tong-Luo-Zhi-Tong (WSTLZT) Decoction is a Chinese prescription with antiosteoporosis effects, especially in patients with abnormal lipid metabolism. To explore the effect and mechanism of WSTLZT on osteoporosis (OP) through adipocyte-derived exosomes. Adipocyte-derived exosomes with or without WSTLZT treated were identified by transmission electron microscopy, nanoparticle tracking analysis (NTA) and western blotting (WB). Co-culture experiments for bone marrow mesenchymal stem cells (BMSCs) and exosomes were performed to examine the uptake and effect of exosome in osteogenesis and adipogenic differentiation of BMSC. MicroRNA profiles, luciferase and IP were used for exploring specific mechanisms of exosome on BMSC. In vivo, 80 Balb/c mice were randomly divided into four groups: Sham, Ovx, Exo (30 μg exosomes), Exo-WSTLZT (30 μg WSTLZT-exosomes), tail vein injection every week. After 12 weeks, the bone microstructure and marrow fat distribution were analysed by micro-CT. ALP, Alizarin red and Oil red staining showed that WSTLZT-induced exosomes from adipocyte can regulate osteoblastic and adipogenic differentiation of BMSC. MicroRNA profiles observed that WSTLZT treatment resulted in 87 differentially expressed miRNAs (p < 0.05). MiR-122-5p with the greatest difference was screened by q-PCR (p < 0.01). The target relationship between miR-122-5p and SPRY2 was tested by luciferase and IP. MiR-122-5p negatively regulated SPRY2 and elevated the activity of MAPK signalling pathway, thereby regulating the osteoblastic and adipogenic differentiation of BMSC. In vivo, exosomes can not only improve bone microarchitecture but also significantly reduce accumulation of bone marrow adipose. WSTLZT can exert anti-OP effect through SPRY2 via the MAKP signalling by miR-122-5p carried by adipocyte-derived exosomes. [ABSTRACT FROM AUTHOR]

Osteoporosis is a chronic inflammatory disease that severely affects quality of life. Cornus officinalis is a Chinese herbal medicine with various bioactive ingredients, among which morroniside is its signature ingredient. Although anti-bone resorption drugs are the main treatment for bone loss, promoting bone anabolism is more suitable for increasing bone mass. Therefore, identifying changes in bone formation induced by morroniside may be conducive to developing effective intervention methods. In this study, morroniside was found to promote the osteogenic differentiation of bone marrow stem cells (BMSCs) and inhibit inflammation-induced bone loss in an in vivo mouse model of inflammatory bone loss. Morroniside enhanced bone density and bone microstructure, and inhibited the expression of IL6, IL1β, and ALP in serum (p < 0.05). Furthermore, in in vitro experiments, BMSCs exposed to 0–256 μM morroniside did not show cytotoxicity. Morroniside inhibited the expression of IL6 and IL1β and promoted the expression of the osteogenic transcription factors Runx2 and OCN. Furthermore, morroniside promoted osteocalcin and Runx2 expression and inhibited TRAF6-mediated NF-κB and MAPK signaling, as well as osteoblast growth and NF-κB nuclear transposition. Thus, morroniside promoted osteogenic differentiation of BMSCs, slowed the occurrence of the inflammatory response, and inhibited bone loss in mice with inflammatory bone loss. [ABSTRACT FROM AUTHOR]