Exercise-derived irisin prevents bone loss via Nrf2 activation and inhibition of STING/NF-κB signaling.

Regulatory effect of Traditional Chinese Medicinal Formula Zuo-Gui-Wan on the Th17/Treg paradigm in mice with bone loss induced by estrogen deficiency

Deletion of SIRT3 inhibits osteoclastogenesis and alleviates aging or estrogen deficiency-induced bone loss in female mice.

Postmenopausal osteoporosis (PMOP) is a severe health issue faced by postmenopausal women. microRNA-128 (miR-128) is associated with aging, inflammatory signaling, and inflammatory diseases, such as PMOP. It has also been reported to modulate in vitro osteogenic/adipogenic differentiation. However, its function in osteoclast formation is unknown.Methods: First, the expression of miR-128 and nuclear factor of activated T cells 1 (Nfatc1, bone resorption master marker) was investigated in bone tissues derived from PMOP patients, while their correlation to each other was also investigated. The levels of miR-128 and Nfatc1 in bone specimens and bone marrow-derived macrophages (BMMs) from mice subjected to ovariectomy (OVX) were also assayed. Next, we employed mice BMMs modified for overexpression and inhibition of miR-128 levels to determine its effect on osteoclast differentiation. Moreover, we generated osteoclastic miR-128 conditional knockout (miR-128Oc-/-) mice and isolated miR-128 deletion-BMMs to observe its biological function on bone phenotype and osteoclastogenesis in vivo, respectively. The miR-128Oc-/- BMMs were used to explore the downstream regulatory mechanisms using pull-down, luciferase reporter, and western-blotting assays. Finally, the impact of miR-128 deficiency on OVX-induced bone loss in mice was evaluated.Results: The miR-128 level was found to be positively correlated with the increase in Nfatc1 level in mouse/human bone specimens and mouse primary BMMs. In vitro experiments demonstrated miR-128 levels that were dependent on activity of osteoclast differentiation and miR-128 overexpression or inhibition in BMMs significantly increased or decreased osteoclastogenesis, respectively. In vivo, we revealed that osteoclastic miR-128 deletion remarkedly increased bone mass through the inhibition of osteoclastogenesis. Mechanistically, we identified sirtuin 1 (SIRT1) as the direct target of miR-128 at the post-transcriptional level during osteoclast differentiation. Increased levels of SIRT1 reduced nuclear factor κB (NF-κB) activity by decreasing the level of acetylation of Lysine 310, as well as inhibiting tumor necrosis factor-α (Tnf-α) and interleukin 1 (IL-1) expressions. Lastly, osteoclastic deletion of miR-128 significantly suppressed OVX-triggered osteoclastogenesis and exerted a protective effect against bone loss in mice.Conclusions: Our findings reveal a critical mechanism for osteoclastogenesis that is mediated by the miR-128/SIRT1/NF-κB signaling axis, highlighting a possible avenue for the further exploration of diagnostic and therapeutic target molecules in PMOP.

We determined the bone mineral density (BMD) and the expression of serum bone formation marker (procollagen type I N-terminal propeptide: PINP) and bone resorption marker (C-terminal telopeptide of collagen: CTX) by ELISA to evaluate ovariectomy-induced osteoporosis in ovariectomized (OVX) mice. The intestinal microbiota of the mice was assessed using 16S rRNA gene sequencing. OVX mice exhibited a lower BMD of 87% with higher serum levels of CTX and PINP compared to sham-operated (sham) mice. The cecum microbiome of OVX mice showed lower bacterial diversity than that of sham mice. TNFα mRNA levels in the colon were 1.6 times higher, and zonula occludens-1 mRNA and protein expression were lower in OVX mice than in sham mice, suggesting that ovariectomy induced inflammation and increased intestinal permeability. Next, we used antibiotic treatment followed by fecal microbiota transplantation (FMT) to remodel the gut microbiota in the OVX mice. A decrease in PINP was observed in antibiotic-treated mice, while there was no change in BMD or CTX between mice with and without antibiotic treatment. Oral transplantation of the luminal cecal content of OVX or sham mice to antibiotic-treated mice did not affect the BMD or PINP and CTX expression. Additionally, transplantation of the luminal contents of OVX or sham mice to antibiotic-treated OVX mice had similar effects on BMD, PINP, and CTX. In conclusion, although ovariectomy induces dysbiosis in the colon, the changes in the gut microbiota may only have a minor role in ovariectomy-induced osteoporosis.

Pharmacological inhibition of protein S-palmitoylation suppresses osteoclastogenesis and ameliorates ovariectomy-induced bone loss

Postmenopausal osteoporosis (PMOP) is the most common type of osteoporosis. Numerous studies have shown that static magnetic fields (SMFs) can inhibit bone loss by regulating bone remodeling. However, there are currently no clinical studies on the treatment of osteoporosis with SMFs. This study aims to investigate the clinical therapeutic effects of moderate static magnetic fields (MMFs) on PMOP. In this paper, we constructed MMF device using neodymium-iron-boron (NdFeB) materials. At the animal level, the effect of MMF exposure for 8 weeks on estrogen deficiency-induced bone loss was investigated by evaluating bone microstructure, mechanical properties, and bone conversion using ovariectomized (OVX) mice. Clinically, a single-blind randomized controlled study in patients with PMOP was designed. PMOP patients aged 55-70 years were recruited and randomized into the control and MMF treatment groups. Clinical assessments of bone mineral density (BMD), bone turnover markers (BTMs) and VAS scores were performed at baseline and day 90, respectively. The results showed that MMF exposure significantly improved BMD, bone mineral content (BMC), bone microarchitecture and bone strength in OVX mice. For bone turnover, MMF increased the number of osteoblasts on the bone surface of OVX mice as well as the level of serum bone formation marker P1NP, while decreasing the number of osteoclasts and the level of serum bone resorption marker β-CTX. The clinical trial's results showed that MMF treatment had a positive effect on the improvement of BMD in the lumbar spine and increased serum P1NP levels while decreased β-CTX levels. In addition, MMF treatment decreased participants' VAS scores for low back pain. The results of both animal and clinical studies demonstrated that MMF treatment improved bone turnover and have a positive effect on BMD improvement, as well as alleviated low back pain in PMOP patients. This study will promote the translational research and clinical application of SMF treatment for osteoporosis. Intervention study of moderate static magnetic field on osteoporosis and iron metabolism in postmenopausal women, ChiCTR2100048604.

Safflower bud inhibits RANKL-induced osteoclast differentiation and prevents bone loss in ovariectomized mice

Effects of (R)-ketamine on reduced bone mineral density in ovariectomized mice: A role of gut microbiota

Osteoporosis is a widespread condition among the elderly, with a particularly high incidence in postmenopausal women aged 50 and above. This disease significantly increases the risk of fractures, adversely affecting the quality of life. Epimedium, a traditional Chinese medicinal herb, has been widely used in the treatment of osteoporosis due to its diverse therapeutic properties. However, Epimedium contains a complex mixture of compounds, including both beneficial and potentially harmful constituents. Therefore, there is a critical need to identify and isolate active monomeric compounds that can effectively treat osteoporosis, thereby enhancing the specificity and efficacy of treatment while reducing the intake of harmful substances. Through an integrated approach utilizing network pharmacology and extensive literature review, we identified five previously unreported anti-osteoporotic monomeric compounds from various traditional agents: Epimedin A (EA), Epimedin B (EB), Epimedoside A (EPA), 4-Hydroxybenzaldehyde (PHBA), and Baohuoside VI. We subsequently evaluated the effects of these compounds on bone marrow-derived macrophages (BMMs) and cranial preosteoblasts. Results from tartrate-resistant acid phosphatase (TRAP) staining and quantitative polymerase chain reaction (qPCR) demonstrated that EA, EB, and EPA significantly inhibited BMM differentiation into osteoclasts in a dose-dependent manner. In contrast, alkaline phosphatase (ALP) staining, Alizarin Red staining, and qPCR results showed that EA and EB promoted the differentiation of cranial preosteoblasts into osteoblasts in a dose-dependent fashion. Furthermore, intraperitoneal administration of EA and EB at doses of 5mg/kg, 10mg/kg, and 20mg/kg in ovariectomized (OVX) mice resulted in a significant increase in bone mineral density and trabecular bone number compared to the OVX group (P < 0.05 compared to OVX group). These findings suggest that EA and EB may mitigate bone loss in OVX mice. Importantly, high doses of EA and EB did not exhibit pharmacological toxicity in various organs, as confirmed by hematoxylin and eosin (HE) staining. In exploring the underlying mechanisms, we found that EA and EB do not modulate the NF-κB signaling pathway, as indicated by the NFKB luciferase reporter assay. Western blot analysis further revealed that EA and EB might not affect osteoporosis progression via the MAPK (ERK and JNK) or NF-κB (P65 and IκBα) pathways. To elucidate the molecular targets, we utilized PharmMapper, Similarity Ensemble Approach, SwissTargetPrediction, and SuperPred to predict potential targets of EA and EB. Intersection analysis using the Ingenuity Pathway Analysis (IPA) database indicated that EA and EB regulate the focal adhesion kinase (FAK) signaling pathway. Molecular docking studies using Autodock confirmed the binding of EA and EB to FAK1 (binding free energy: -13.012kJ/mol and -14.0164kJ/mol) and FAK2 (binding free energy: -5.815kJ/mol and -6.4852kJ/mol). qPCR analysis further demonstrated that EA and EB significantly inhibited FAK1 and FAK2 gene expression in osteoclasts while promoting their expression in osteoblasts at very high doses. In conclusion, EA and EB, identified as active monomeric compounds in Epimedium, may exert their anti-osteoporotic effects by modulating the FAK signaling pathway, thereby enhancing bone mineral density and improving the quality of life for patients with osteoporosis. This study provides new insights into the pathogenesis of osteoporosis and the development of targeted anti-osteoporosis therapies. Further research is warranted to validate the role of EA and EB in modulating osteoporosis progression via the FAK signaling pathway.

Osteoporosis is characterized by decreased bone mass and disrupted microarchitecture. Gut microbiota-derived factors may regulate bone homeostasis. This study investigated the effects and mechanisms of Lacticaseibacillus rhamnosus LGG, conditioned medium (LCM) on osteoclastogenesis and bone loss. RANKL-induced osteoclast differentiation in bone marrow-derived macrophages (BMMs) was assessed by TRAP staining, F-actin ring imaging, resorption pit assay, qRT-PCR, and Western blotting. Ovariectomized (OVX) mice received oral LCM for 8weeks. Bone architecture was analyzed by micro-CT and histology (H&E, TRAP, immunohistochemistry). Serum bone turnover markers and toxicity indicators were measured by ELISA. Transcriptome sequencing was performed on LCM-treated BMMs, followed by differential expression and KEGG enrichment analyses. Pathway involvement was validated via pharmacological inhibition. LCM demonstrated favorable biocompatibility while significantly reducing TRAP-positive cell number, F-actin ring formation, and bone resorption area in RANKL-treated BMMs. The expression of osteoclastogenic markers was markedly downregulated. In OVX mice, LCM treatment preserved the trabecular microarchitecture of lumbar vertebrae and femur, increased BV/TV, Tb.Th, and Tb.N, and reduced osteoclast number. Serum bone resorption marker (β-CTx) decreased, while bone formation markers (BALP and P1NP) showed no significant change. No adverse effects were observed in body weight or liver and kidney function indices. Transcriptome analysis revealed NF-κB pathway suppression. Western blotting confirmed that LCM reduced phosphorylation of IKKα, IκBα, and p65. Regulation of TLR6 can restore NF-κB activation and osteoclast function. LCM alleviates bone loss by inhibiting osteoclastogenesis mediated via the TLR6/NF-κB signaling pathway. LGG shows promise as a potential therapeutic agent, warranting further clinical investigation.

Isonardosinone suppresses osteoclastogenesis through TRAF2/TRAF6-mediated disruption of calcium signaling and coordinate inhibition of MAPK/NF-κB pathways

This study was conducted to investigate the inhibitory effects of the cell-free culture supernatant of Lactobacillus curvatus Wikim 38 (LC38-CS) on RANKL-induced osteoclast differentiation and bone loss in a mice model of ovariectomy-induced post-menopausal osteoporosis. LC38-CS inhibited the RANKL-induced differentiation of bone marrow-derived macrophages (BMDMs) into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by LC38-CS treatment of RANKL-treated BMDMs. In addition, LC38-CS decreased the RANKL-induced activation of the TRAF6/NF-κB/MAPKs axis at the early stage and the expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. PRMT1 and ADMA levels, new biomarkers for osteoclastogenesis, were decreased by LC38-CS treatment. The administration of LC38-CS increased bone volume and bone mineral density in ovariectomized mice in μ-CT analysis. These findings suggest that LC38-CS inhibited RANKL-induced osteoclast differentiation by the downregulation of molecular mechanisms and exerted anti-osteoporotic effects.

AimDepression is a common symptom in people with osteoporosis. (R)‐ketamine produced greater potency and longer‐lasting antidepressant‐like actions than (S)‐ketamine in rodents. Here, we examined the effects of two ketamine enantiomers on the reduced bone mineral density (BMD) in the ovariectomized (OVX) mice which is an animal model of postmenopausal osteoporosis.MethodsFemale ddY mice were OVX or sham‐operated. Subsequently, saline (10 mL/kg/d, twice weekly), (R)‐ketamine (10 mg/kg/d, twice weekly), or (S)‐ketamine (10 mg/kg/d, twice weekly) was administered intraperitoneally into OVX or sham mice for the 6 weeks. The femur from all mice was collected 3 days after the final injection, and BMD in the femur was measured.ResultsThe reduction of cortical BMD and total BMD in the OVX mice was significantly ameliorated after subsequent repeated intermittent administration of (R)‐ketamine, but not (S)‐ketamine.ConclusionThe study shows that (R)‐ketamine can ameliorate the reduced cortical BMD and total BMD in OVX mice. Therefore, (R)‐ketamine would be a novel therapeutic drug for women with osteoporosis.

Foxf1 knockdown promotes BMSC osteogenesis in part by activating the Wnt/β-catenin signalling pathway and prevents ovariectomy-induced bone loss

Bisabolangelone targets CSF1R to impede osteoclastogenesis and attenuate estrogen-deficiency bone loss.