The Mechanism of Action and Experimental Verification of Narenmandula in the Treatment of Postmenopausal Osteoporosis.

BACKGROUND: Narenmandula is a classic ancient remedy in Inner Mongolia, historically used for gastrointestinal diseases. In recent decades, Inner Mongolia Medical University found that it has a significant effect in promoting fracture healing and increasing bone density, and has been used to treat postmenopausal osteoporosis (PMOP), but its mechanism is unclear. OBJECTIVE: Identify the mechanism of action of Narenmandula for PMOP treatment. METHODS: Network pharmacology, molecular docking and ovarian departing rat models were used to verify the relevant mechanism of Narenmandula in the treatment of PMOP. RESULTS: We confirmed that NRMDL prescription can improve OVX-induced bone loss, improve trabecular density, and relieve osteoporosis. Upon screening of network pharmacology, we obtained 238 overlapping genes of Narenmandula and PMOP, and analyzed AKT, IL1B, and IL6 as key genes by network topology. Among the 1143 target genes that interact with PMOP, 107 NRMDL active compounds correspond to 345 target genes and 238 overlapping genes. Network topology analysis showed the top 8 active ingredients, such as quercetin and kaempferol, and the top 20 key genes, such as AKT, IL1B, IL6, INS, JUN, STAT3, TNF, TP53, etc. Enrichment analysis revealed involvement of PI3K-Akt, HIF-1, FoxO, MAPK, and TNF signaling pathways. In addition, we found the most important active compounds bind tightly to core proteins, which were verified by molecular docking analysis. The AKT-related pathway had good binding energy, and the pathway was verified by cell and animal experiments. CONCLUSION: The potential mechanism and efficacy of Narenmandula against PMOP may be related to the PI3K-AKT pathway.

Morroniside Inhibits Inflammatory Bone Loss through the TRAF6-Mediated NF-κB/MAPK Signalling Pathway.

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, IL1ß, 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 IL1ß 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.

Quercetin Attenuates Osteoporosis in Orchiectomy Mice by Regulating Glucose and Lipid Metabolism via the GPRC6A/AMPK/mTOR Signaling Pathway.

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.

Current status and development trend of miRNAs in osteoporosis-related research: A bibliometric analysis.

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.