Shengu granules ameliorate ovariectomy-induced osteoporosis by the gut-bone-immune axis

Introduction

Postmenopausal osteoporosis (PMOP) is a common chronic disease, and the loss of bone density and bone strength after menopause are its main symptoms. Effective treatments for PMOP are still uncertain, but Chinese medicine has some advantages in slowing down bone loss. Shengu granules are often used clinically to treat PMOP. It has been shown to be an effective prescription for the treatment of PMOP, and there is evidence that gut flora may play an important role. However, whether Shengu granules attenuate PMOP by modulating gut flora and related mechanisms remains unclear.

Methods

In this study, we mainly examined the bone strength of the femur, the structure of the intestinal microbiota, SCFAs in the feces and the level of FOXP3 cells in the colon. To further learn about the inflammation response, the condition of the mucosa and the level of cytokines in the serum also included in the testing. In addition, to get the information of the protein expression, the protein expression of OPG and RANKL in the femur and the protein expression of ZO-1 and Occludin in the colon were taken into account.

Results

The osteoporosis was significantly improved in the SG group compared with the OVX group, and the diversity of intestinal flora, the secretion level of SCFAs and the expression level of FOXP3 were significantly increased compared with the OVX group. In terms of inflammatory indicators, the intestinal inflammation scores of the SG group was significantly lower than those in the OVX group. Additionally, the serum expression levels of IL-10 and TGF-β in the SG group were significantly increased compared with the OVX group, and the expression levels of IL-17 and TNF-α were significantly decreased compared with the OVX group. In terms of protein expression, the expression levels of ZO-1, Occluding and OPG were significantly increased in the SG group compared with the OVX group, and the expression level of RANKL was significantly decreased compared with the OVX group.

Discussion

Shengu granules treatment can improve the imbalance of intestinal flora, increase the secretion of SCFAs and the expression of FOXP3, which reduces the inflammatory response and repairs the intestinal barrier, as well as regulates the expression of OPG/RANKL signaling axis. Overall, Shengu granules ameliorate ovariectomy-induced osteoporosis by the gut-bone-immune axis.

Carnosol inhibits osteoclastogenesis in vivo and in vitro by blocking the RANKL‑induced NF‑κB signaling pathway

Bone homeostasis is maintained by osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Disruption of bone homeostasis due to excessive osteoclastogenesis or reduced osteogenesis results in various disorders, such as postmenopausal osteoporosis. Receptor activator of NF-κB ligand (RANKL) stimulation of the NF-κB signaling pathway is essential in osteoclastogenesis. The aim of the present study was to investigate the novel effects of carnosol, an active compound found in Rosmarinus officinalis, on RANKL-induced osteoclastogenesis both in vitro and in vivo. TRAP staining showed that carnosol significantly inhibited osteoclasts differentiation of bone marrow monocytes and RAW264.7 cells. Western blot results showed that the protein expression levels of osteoclastogenesis-associated genes, including cathepsin K, tartrate-resistant acid phosphatase and MMP-9, were markedly inhibited by carnosol, which may have suppressed osteoclast function. Furthermore, western blot and immunofluorescent staining results revealed that carnosol markedly suppressed the phosphorylation of p65 induced by RANKL and blocked its nuclear translocation, indicating the suppression of NF-κB signaling pathway. H&E staining and micro-CT results showed that in vivo treatment with carnosol significantly attenuated ovariectomy-induced bone loss in mice. In conclusion, the present study indicated that carnosol may suppress osteoclastogenesis both in vivo and in vitro by inhibiting the activation of the NF-κB signaling pathway. Carnosol may therefore be a potential novel therapeutic candidate for the clinical treatment of osteoclast-related disorders.

Naringin promotes osteogenesis and ameliorates osteoporosis development by targeting JAK2/STAT3 signalling

Osteoporosis is a systemic bone metabolism disorder, which increases the risk of fractures, and in severe cases it may cause disability or even death. An important factor contributing to osteoporosis is the imbalance between bone formation and resorption. Naringin was reported to promote osteoblast differentiation, thus enhancing bone formation and alleviating osteoporosis development. However, the signalling pathways related to the regulatory mechanism of naringin in osteoporosis development are not clear. Proliferation of bone mesenchymal stem cells (BMSCs) treated with naringin in vitro was detected by CCK-8. An osteogenesis differentiation medium supplemented with naringin was applied to explore the effects of naringin on BMSC osteogenic differentiation, as detected by Alizarin red staining. Ovariectomy (OVX)-induced postmenopausal osteoporosis (PMOP) rats were orally administered with naringin. Dual-energy X-ray absorptiometry (DEXA) and micro-CT were applied to measure bone mineral density (BMD), bone volume/total volume (BV/TV), trabecula thickness (Tb.Th), trabecula number (Tb.N), trabecular separation (Tb.Sp) and bone surface/bone volume (BS/BV). H&E staining was performed to show pathological changes of the femur in PMOP rats after naringin treatment. Bone metabolism indicators were assessed by ELISA. We found that naringin suppressed the activation of the JAK2/STAT3 pathway. Naringin promoted BMSC proliferation and osteogenic differentiation. Furthermore, naringin alleviates bone loss and improves abnormal bone metabolism of PMOP rats. Collectively, naringin promotes BMSC osteogenic differentiation to ameliorate osteoporosis development by targeting JAK2/STAT3 signalling.

Iron accumulation regulates osteoblast apoptosis through lncRNA XIST/miR-758-3p/caspase 3 axis leading to osteoporosis

Postmenopausal osteoporosis (PMOP) is mainly caused by multiple factors. Recent studies have suggested that iron accumulation (IA) was closely related to PMOP. However, the detailed molecular mechanisms have not been well demonstrated. We constructed the IA mouse model by intraperitoneal injections of ferric ammonium citrate (FAC) and cell model by culturing with the medium containing FAC. Osteoporosis was confirmed in mouse bone tissues using H&E staining, and the level of serum ferritin, alkaline phosphatase (ALP), procollagen-1 N-terminal peptide (P1NP), and osteocalcin in mice was examined by ELISA. The expressions of XIST and miR-758-3p were detected by qRT-PCR. Cell proliferation and apoptosis were measured by CCK-8, TUNEL, and flow cytometry. The expression levels of apoptotic-related proteins were evaluated by western blot. Dual luciferase reporter assay was used to examine the molecular interaction. The expressions of ALP, P1NP, and osteocalcin, and the H&E staining of bone tissues in mice were analyzed to confirm the biological function of XIST and miR-758-3p in vivo. XIST was up-regulated while miR-758-3p was down-regulated in IA mouse and cell models. XIST knockdown significantly reduced FAC-induced osteoblast apoptosis, which was mimicked by transfection with miR-758-3p mimics. XIST acted as a sponge of miR-758-3p, which targeted caspase 3. IA led to the high expression of XIST and promoted osteoblast apoptosis through miR-758-3p/caspase 3. Transfection with shXIST or miR-758-3p mimics alleviated IA-induced mouse osteoporosis. IA regulated osteoblast apoptosis through XIST/miR-758-3p/caspase 3 axis, which might provide alternative targets for the treatment of osteoporosis.

Overall adjustment acupuncture for postmenopausal osteoporosis (PMOP): a study protocol for a randomized sham-controlled trial

BACKGROUND

Osteoporosis is becoming more prevalent in aging societies worldwide, and the economic burden attributable to osteoporotic fractures is substantial. The medications presently available to treat osteoporosis have side effects. Acupuncture is widely used for treating osteoporotic postmenopausal women because it is non-invasive and has fewer side effects, but the powerful clinical evidence for its efficacy remains insufficient. Our study intends to explore the effect of overall adjustment acupuncture (OA) in the treatment of postmenopausal osteoporosis (PMOP).

METHODS/DESIGN

This study is a randomized, sham-controlled, patient- and assessor-blinded trial and aims to evaluate the effect of OA in women with PMOP. We will recruit 104 women aged 45-70 years with a diagnosis of PMOP. Participants will be randomly allocated in a 1:1 ratio to the OA group and the sham acupuncture (SA) group. Both groups will receive real herbal medicine treatment as a basic treatment twice a day for 3 months, the OA group receives real acupuncture treatment and the SA group receives placebo acupuncture treatment (non-penetrating, sham skin-needle therapy, sham cupping). All patients will receive acupuncture treatment twice per week for 3 months. The primary outcome is bone mineral density (BMD) and the secondary outcomes include estradiol (E2), follicle-stimulating hormone (FSH), bone gla protein (BGP), bone alkaline phosphatase (BALP), total antioxidant capacity (TAC), advanced oxidation protein products (AOPP), PPARγ, β-catenin, FoxO3a levels, visual analog pain scale score (VAS), Traditional Chinese medicine (TCM) syndrome scores and quality of daily life score (QOL). Outcome measures will be collected at baseline, middle of the treatment (1.5 months), the end of treatment (3 months). The present protocol followed the SPIRIT guidelines and fulfills the SPIRIT Checklist.

CONCLUSION

This study will be conducted to compare the efficacy of OA versus SA. This trial should help to evaluate whether OA can effectively prevent and treat PMOP by improving the estrogen levels of postmenopausal women. The mechanism is to improve the imbalance of osteogenic differentiation and lipogenesis of bone-marrow cells under oxidative stress.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ID: ChiCTR1800017581. Registered on 5 August 2018. URL: http://www.chictr.org.cn.

miR-128 plays a critical role in murine osteoclastogenesis and estrogen deficiency-induced bone loss

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-128^Oc-/-) mice and isolated miR-128 deletion-BMMs to observe its biological function on bone phenotype and osteoclastogenesis in vivo, respectively. The miR-128^Oc-/- 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.

H19 and Foxc2 synergistically promotes osteogenic differentiation of BMSCs via Wnt-β-catenin pathway

OBJECTIVE

To investigate the mechanism of H19 on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

METHODS

Ovariectomized (OVX) mouse model was established. RNA immunoprecipitation and RNA pull-down assays were performed to determine the correlation between H19 and forkhead box C2 (Foxc2). Chromatin immunoprecipitation assay was used to identify whether Foxc2 binds to the Wnt4 promoter region. Molecules expressions were measured by quantitative real-time polymerase chain reaction and western blot.

RESULTS

We found that H19 expression was reduced in the serum of patients with postmenopausal osteoporosis and BMSCs of OVX mice, and overexpression of H19 promoted osteogenic differentiation of BMSCs. Additionally, Foxc2 could bind to the Wnt4 promoter and promote its transcription. We also showed that H19 could bind to Foxc2, and H19/Foxc2 regulated Wnt promoter expression in a synergistic fashion, and H19/Foxc2 regulated osteogenic differentiation of BMSCs through Wnt-β-catenin pathway.

CONCLUSION

H19 and Foxc2 synergistically promoted osteogenic differentiation of BMSCs via Wnt-β-catenin pathway.

DGCR5 induces osteogenic differentiation by up-regulating Runx2 through miR-30d-5p

BACKGROUND

Postmenopausal osteoporosis (PMOP) is a metabolic bone disease caused by unbalance between osteoblast bone formation and osteoclast bone resorption. In this study, the moderating effect of DGCR5 on osteogenic differentiation and its role in PMOP was assessed.

METHODS

The expression levels of DGCR5, miR-30d-5p, and Runt-related transcription factor 2 (Runx2) mRNA and protein were determined by qRT-PCR and western blot, separately. The bone marrow human mesenchymal stem cells (hMSCs) were isolated from bone marrow of patients with PMOP or the healthy control. ALP activity and bone mineral density (BMD) were detected to reflect the osteogenic differentiation status. RIP and RNA pull-down assay were performed to explore the combination and interaction between DGCR5 and miR-30d-5p.

RESULTS

Compared with the healthy control group (n = 20), DGCR5 was down-regulated in hMSCs from patients with PMOP (n = 20). Overexpression of DGCR5 induced osteogenic differentiation of hMSCs. DGCR5 up-regulated the expression of Runx2 through miR-30d-5p. DGCR5 up-regulated the expression of Runx2 through miR-30d-5p to induce osteogenic differentiation of hMSCs.

CONCLUSION

DGCR5 negatively regulates miR-30d-5p, and it up-regulates Runx2 through miR-30d-5p, thereby inducing osteogenic differentiation of hMSCs, which may help to delay PMOP development.

Effects of pulsed electromagnetic fields on postmenopausal osteoporosis

Postmenopausal osteoporosis (PMOP) is considered to be a well-defined subject that has caused high morbidity and mortality. In elderly women diagnosed with PMOP, low bone mass and fragile bone strength have been proven to significantly increase risk of fragility fractures. Currently, various anabolic and anti-resorptive therapies have been employed in an attempt to retain healthy bone mass and strength. Pulsed electromagnetic fields (PEMFs), first applied in treating patients with delayed fracture healing and nonunions, may turn out to be another potential and effective therapy for PMOP. PEMFs can enhance osteoblastogenesis and inhibit osteoclastogenesis, thus contributing to an increase in bone mass and strength. However, accurate mechanisms of the positive effects of PEMFs on PMOP remain to be further elucidated. This review attempts to summarize recent advances of PEMFs in treating PMOP based on clinical trials, and animal and cellular studies. Possible mechanisms are also introduced, and the future possibility of application of PEMFs on PMOP are further explored and discussed. Bioelectromagnetics. 38:406-424, 2017. © 2017 Wiley Periodicals, Inc.