Systemic Inflammatory Regulators Associated with Osteoporosis: A Bidirectional Mendelian Randomization Study.

To elucidate the precise upstream and downstream regulatory mechanisms of inflammatory factors in osteoporosis (OP) progression and to establish a causal relationship between inflammatory factors and OP. We conducted bidirectional Mendelian randomization (MR) analyses using data for 41 cytokines obtained from three independent cohorts comprising 8293 Finnish individuals. Estimated bone mineral density (eBMD) data were derived from 426,824 UK Biobank White British individuals (55% female) and fracture data from 416,795 UK Biobank participants of European ancestry. The inverse variance-weighted method was the primary MR analysis approach. We employed other methods as complementary approaches for mutual corroboration. To test for pleiotropy and heterogeneity, we used the MR-Egger regression, MR-pleiotropy residual sum and outlier global test, and the Cochrane Q test. Macrophage inflammatory protein (MIP)-1α and interleukin (IL)-12p70 expression associated negatively and causally with eBMD (ß = -0.017 [MIP-1α], ß = -0.011 [IL-12p70]). Conversely, tumor necrosis factor-related apoptosis-inducing ligand was associated with a decreased risk of fractures (Odds Ratio: 0.980). Additionally, OP influenced the expression of multiple inflammatory factors, including growth-regulated oncogene-α, interferon-gamma, IL-6, beta nerve growth factor, and IL-2. Finally, we discovered complex bidirectional causal relationships between IL-8, IL-10, and OP. Specific inflammatory factors may contribute to OP development or may be causally affected by OP. We identified a bidirectional causal relationship between certain inflammatory factors and OP. These findings provide new perspectives for early prediction and targeted treatment of OP. Larger cohort studies are necessary in the future to further validate these findings.

Corynoline Suppresses Osteoclastogenesis and Attenuates ROS Activities by Regulating NF-κB/MAPKs and Nrf2 Signaling Pathways.

Declining estrogen production in postmenopausal females causes osteoporosis in which the resorption of bone exceeds the increase in bone formation. Although clinical drugs are currently available for the treatment of osteoporosis, sustained medication use is accompanied by serious side effects. Corydalis bungeana Herba, a famous traditional Chinese herb listed in the Chinese Pharmacopoeia Commission, constitutes various traditional Chinese Medicine prescriptions, which date back to thousands of years. One of the primary active components of C. bungeana Turcz. is Corynoline (Cor), a plant isoquinoline alkaloid derived from the Corydalis species, which possesses bone metabolism disease therapeutic potential. The study aimed at exploring the effects as well as mechanisms of Cor on osteoclast formation and bone resorption. TRAcP staining, F-actin belt formation, and pit formation were employed for assessing the osteoclast function. Western blot, qPCR, network pharmacology, and docking analyses were used for analyzing the expression of osteoclast-associated genes and related signaling pathways. The study focused on investigating how Cor affected OVX-induced trabecular bone loss by using a mouse model. Cor could weaken osteoclast formation and function by affecting the biological receptor activators of NF-κB and its ligand at various concentrations. Mechanistically, Cor inhibited the NF-κB activation, and the MAPKs pathway stimulated by RANKL. Besides, Cor enhanced the protein stability of the Nrf2, which effectively abolished the RANKL-stimulated ROS generation. According to an OVX mouse model, Cor functions in restoring bone mass, improving microarchitecture, and reducing the ROS levels in the distal femurs, which corroborated with its in vitro antiosteoclastogenic effect. The present study indicates that Cor may restrain osteoclast formation and bone loss by modulating NF-κB/MAPKs and Nrf2 signaling pathways. Cor was shown to be a potential drug candidate that can be utilized for the treatment of osteoporosis.

Carnitine functions as an enhancer of NRF2 to inhibit osteoclastogenesis via regulating macrophage polarization in osteoporosis.

Osteoporosis, which manifests as reduced bone mass and deteriorated bone quality, is common in the elderly population. It is characterized by persistent elevation of macrophage-associated inflammation and active osteoclast bone resorption. Currently, the roles of intracellular metabolism in regulating these processes remain unclear. In this study, we initially performed bioinformatics analysis and observed a significant increase in the proportion of M1 macrophages in bone marrow with aging. Further metabolomics analysis demonstrated a notable reduction in the expression of carnitine metabolites in aged macrophages, while carnitine was not detected in osteoclasts. During the differentiation process, osteoclasts took up carnitine synthesized by macrophages to regulate their own activity. Mechanistically, carnitine enhanced the function of Nrf2 by inhibiting the Keap1-Nrf2 interaction, reducing the proteasome-dependent ubiquitination and degradation of Nrf2. In silico molecular ligand docking analysis of the interaction between carnitine and Keap1 showed that carnitine binds to Keap1 to stabilize Nrf2 and enhance its function. In this study, we found that the decrease in carnitine levels in aging macrophages causes overactivation of osteoclasts, ultimately leading to osteoporosis. A decrease in serum carnitine levels in patients with osteoporosis was found to have good diagnostic and predictive value. Moreover, supplementation with carnitine was shown to be effective in the treatment of osteoporosis.

Ginsenoside Rb2 exhibits therapeutic value for male osteoporosis in orchiectomy mice by suppressing osteoclastogenesis and modulating NF-κB/MAPK signaling pathways.

Osteoporosis (OP) is a systemic disorder characterized by decreased bone mass as well as deteriorated microarchitecture. Although OP in men is common, it has received much less attention than that in women. Ginseng, a famous traditional herb in Asia, is used to strengthen and repair bones by invigorating vital bioenergy and maintaining body homeostasis in dietary intake and clinical applications. However, there is currently no study investigating the impact of ginseng and its active compounds on male osteoporosis. In this study, RNA sequencing and bioinformatic analysis were conducted to reveal the influence of Ginsenoside-Rb2 on RAW264.7 cells and its underlying signaling pathways. The potential anti-osteoporosis effects of Rb2 as well as its molecular mechanisms were elucidated in RAW264.7 cells and BMMs by TRAP staining, F-actin belt staining, qRT-PCR and WB. Moreover, orchiectomy (ORX) was utilized to demonstrate the influence of Rb2 on bone mass loss in vivo by micro-CT scanning, and H&E, TRAP, and IHC staining. The results suggested that Rb2 suppressed osteoclastogenesis and mitigated bone loss in orchiectomy mice through NF-κB/MAPK signaling pathways. These findings indicate that ginseng as well as its active component Rb2 have potential therapeutic value in the management of osteoporosis in men.

Identifying the effective combination of acupuncture and traditional Chinese medicinal herbs for postmenopausal osteoporosis therapy through studies of their molecular regulation of bone homeostasis.

Worldwide, as the population age, osteoporosis is becoming increasingly common, and osteoporotic fractures have a significant economic burden. Postmenopausal women are the most susceptible to developing osteoporosis and the most critical time to prevent it is during the perimenopausal and early menopausal years. In this regard, we hypothesize rational combination of acupuncture and Traditional Chinese Medicine (TCM) in the form of herbal extract could prevent osteoporosis in women. Estrogen deficiency during menopause causes low-level inflammation that stimulates the formation of osteoclasts, the bone-resorbing cells, and simultaneously inhibits the viability and function of osteoblasts, the bone-forming cells. The most potent inflammatory cytokine in skeletal homeostasis is the receptor activator of nuclear factor kappa B ligand (RANKL) that stimulates osteoclast function. Conversely, the canonical Wnt pathway is essential for osteoblastogenesis and bone formation, and estrogen deficiency leads to diminished functioning of this pathway. TCM and acupuncture could target the RANKL and the Wnt pathway in favorable ways to prevent the accelerated bone loss experienced during the early menopausal stage and promote the gain in bone mass in postmenopausal women. In this review, we propose a rational combination of specific TCM and acupuncture targeting those signaling molecules/pathways by the drugs that are in clinical use for the treatment of postmenopausal osteoporosis. Our rational approach revealed that Danshen (Radix Salviae Miltiorrhizae) could exert a synergistic effect with acupuncture. We then propose a translational path for developing the putative combination in women with postmenopausal osteoporosis to curtail the risk of osteoporotic fractures.

The potential pharmacological mechanism of prunetin against osteoporosis: transcriptome analysis, molecular docking, and experimental approaches.

BACKGROUND: Prunetin is an O-methylated isoflavone, known for its beneficial properties. However, its specific pharmacological effects in the treatment of osteoporosis (OP) remain poorly understood. This study aims to elucidate the mechanisms underlying the antiosteoporotic effects of prunetin through a combination of bioinformatics analysis and cell experiments. METHODS: We gathered predicted targets of prunetin from various online platforms. Differential expression analysis of mRNAs in patients with OP was conducted using the Limma package, based on the GSE35959 dataset. A PPI network diagram was visualized and analyzed using Cytoscape 3.7.2 software. Molecular docking was employed to assess the binding affinity between ligands and receptors, and selected key genes were further validated through cell experiments. RESULTS: A total of 4062 differentially expressed genes (DEGs) were identified from the GSE35959 dataset. Among these, 58 genes were found to overlap with the targets of prunetin, indicating their potential as therapeutic targets. The enrichment analysis indicated these targets were mainly enriched in MAPK, FoxO, and mTOR signaling pathways. The molecular docking analysis demonstrated that prunetin exhibited strong binding activity with the core targets. Furthermore, cell experiments revealed that prunetin effectively reversed the expression levels of ALB, ESR1, PTGS2, and FGFR1 mRNA in MC3T3-E1 cells treated with dexamethasone (DEX). CONCLUSION: Our research revealed the multi-pathway and multi-target features of prunetin in treating OP, shedding light on the potential mechanisms underlying the effectiveness of prunetin against OP. These findings serve as a theoretical foundation for future drug development in this field.

Causal Effect of Selenium Levels on Osteoporosis: A Mendelian Randomization Study.

Prior research has demonstrated equivocal associations between selenium (Se) concentrations and osteoporosis (OP), yielding inconclusive findings. The purpose of the current study was to examine the potential correlation between Se levels and the risk of OP by using the Mendelian randomization (MR) study design. The genetic variants related to Se levels were obtained from a meta-analysis of a Genome-Wide Association Study (GWAS) conducted on toenail Se levels (n = 4162) and blood Se levels (n = 5477). The data summary for OP and bone mineral density (BMD) was obtained by utilizing the GWAS database. To examine the association between Se levels and BMD and OP, we employed three statistical methods: inverse variance weighted, weighted median, and MR-Egger. The reliability of the analysis was verified by sensitivity testing. All three methods of MR analysis revealed that Se levels had no effect on OP risk. In addition, the sensitivity analysis revealed no heterogeneity or pleiotropy, and the significance of the overall effect remained unaffected by single-nucleotide polymorphisms (SNPs), as determined by the leave-one-out analysis, indicating that our findings are relatively reliable. The results of our study indicate that there is no causal association between Se levels and the risk of OP. However, additional investigation is necessary to ascertain whether there is a potential association between these variables.

Decoding the mechanism of Eleutheroside E in treating osteoporosis via network pharmacological analysis and molecular docking of osteoclast-related genes and gut microbiota.

Objective: Eleutheroside E (EE) is an anti-inflammatory natural compound derived from the edible medicinal herb Acanthopanax senticosus. This study aims to investigate the underlying mechanism of the anti-osteoporosis action of EE through network pharmacology, molecular docking and gut microbiota. Materials and methods: Network pharmacology was used to explore the potential core targets and main pathways mediated by EE in osteoporosis (OP) treatment. Molecular docking was exploited to investigate the interactions between the active anti-OP compounds in EE and the potential downstream targets. Following the multi-approach bioinformatics analysis, ovariectomy (OVX) model was also established to investigate the in vivo anti-OP effects of EE. Results: The top 10 core targets in PPI network were TP53, AKT1, JUN, CTNNB1, STAT3, HIF1A, EP300, CREB1, IL1B and ESR1. Molecular docking results that the binding energy of target proteins and the active compounds was approximately between -5.0 and -7.0 kcal/mol, which EE has the lowest docking binding energy with HIF1A. Enrichment analysis of GO and KEGG pathways of target proteins indicated that EE treatment could potentially alter numerous biological processes and cellular pathways. In vivo experiments demonstrated the protective effect of EE treatment against accelerated bone loss, where reduced serum levels of TRAP, CTX, TNF-α, LPS, and IL-6 and increased bone volume and serum levels of P1NP were observed in EE-treated mice. In addition, changes in gut microbiota were spotted by 16S rRNA gene sequencing, showing that EE treatment increased the relative abundance of Lactobacillus and decreased the relative abundance of Clostridiaceae. Conclusion: In summary, these findings suggested that the characteristics of multi-target and multi-pathway of EE against OP. In vivo, EE prevents the onset of OP by regulating gut microbiota and inflammatory response and is therefore a potential OP drug.

Diet-derived antioxidants and osteoporosis: A Mendelian randomization study.

BACKGROUND: Antioxidants can prevent osteoporosis, but the association between serum antioxidants and the cause of osteoporosis remains unknown. We aimed to utilize Mendelian randomization (MR) to determine whether genetically predicted serum levels of diet-derived antioxidants can affect the risk of osteoporosis, to determine the effect of dietary supplementation of antioxidants. METHODS: Genetic variants associated with diet-derived antioxidants were selected from the genome-wide association studies. A total of 12,946 osteoporosis cases and 506,624 healthy controls were obtained from UK Biobank (UKB) and Genetic Factors of Osteoporosis (GEFOS) consortia. We implemented a two-sample MR design and performed several sensitivity analyses to evaluate the causal relationship. RESULTS: In UKB, the genetically predicted higher ß-carotene (OR = 0.863, p = 7.37 × 10-6, power = 100%) and γ-tocopherol (OR = 0.701, p = 0.021, power = 5%) had an inverse relationship with osteoporosis. However, only the association of serum ß-carotene passed FDR correction. In GEFOS, there were no significant diet-derived antioxidants. The direction of the association of ß-carotene with osteoporosis (OR = 0.844, p = 0.106, power = 87%) was consistent with that in the UKB dataset. A fixed-effects meta-analysis confirmed that ß-carotene (OR = 0.862, p = 2.21 × 10-6) and γ-tocopherol (OR = 0.701, p = 2.31 × 10-2) could decrease the risk of osteoporosis. To reduce exclusion limit bias, we used total body bone mineral density, lumbar spine bone mineral density and femoral neck bone mineral density as surrogates and found that the genetically elevated circulating ß-carotene level could increase total body BMD (beta = 0.043, p-value = 8.26 x 10-5, power = 100%), lumbar spine BMD (beta = 0.226, p-value = 0.001, power = 100%) and femoral neck BMD(beta = 0.118, p-value = 0.016, power = 100%). CONCLUSIONS: We observed that genetically predicted serum ß-carotene could elevate BMD and prevent osteoporosis.

Zuogui Wan alleviates ovariectomy-induced osteoporosis by maintaining FoxO3 and increasing NK1R.

Sixty Sprague-Dawley female rats were randomly divided into sham-operated groups and five ovariectomy (OVX) subgroups. Rats subjected to sham and OVX were treated with the vehicle, alendronate, and Zuogui Wan (ZGW) at the doses of low, medium and high lyophilized powder daily for 3 months, respectively. The gene or protein expression of NK1R, PPAR γ, and OSX were assayed by either quantitative polymerase chain reaction or Western blot analysis. The results showed that compared with the OVX group, ZGW could reduce the level of PPARγ and increase the levels of OSX and. Meanwhile, ZGW could prevent bone loss. In addition, we found ZGW upregulated for the NK1R mRNA or protein expression by promoting the expression level of transcription factor FoxO3 and increasing its binding to the NK1R promoter region -700/-200 sequence. These results suggest that the regulation of FoxO3 and NK1R played a role and contributed to the mechanism of ZGW underlying the increase in bone mass in the OVX rat model.

To investigate the mechanism of Yiwei Decoction in the treatment of premature ovarian insufficiency-related osteoporosis using transcriptomics, network pharmacology and molecular docking techniques.

To investigate the molecular mechanism of Yiwei Decoction (YWD) in preventing Premature ovarian insufficiency (POI)-related osteoporosis from the hypothalamic perspective , and to screen for the key active and acting molecules in YWD. Cyclophosphamide was used to create the POI rat model. Groups A, B, and C were established. The Model + YWD group was group A, the model control group was group B, and the normal control group was group C. ELISA was used to determine serum GnRH and FSH levels after gavage. The transcription levels of mRNAs in each group's hypothalamus tissues were examined using RNA-seq sequencing technology. The GSEA method was used to enrich pathways based on the gene expression levels of each group. The TCM-active ingredient-target-disease network map was created using differentially expressed mRNAs (DEmRNAs) and network pharmacology. The molecular docking method was employed to investigate the affinity of the active ingredient with key targets. GnRH and FSH levels in POI rats' serum were reduced by YWD. Between groups A and B, there were 638 DEmRNAs (P < 0.05) and 55 high-significance DEmRNAs (P-adjust < 0.01). The MAPK, Hedgehog, Calcium, and B cell receptor pathways are primarily enriched in DEmRNAs from Group A and Group B. The GSEA pathway enrichment analysis indicates that YWD may regulate Long-term potentiation, Amphetamine addiction, and the Renin-angiotensin system and play a role in preventing osteoporosis. The Chinese herbal medicine (CHM)-Active ingredient-Target-disease network map includes 137 targets, 4 CHMs, and 22 active ingredients. The result of docking indicated that Stigmasterol, interacts well with the core proteins ALB, VCL and KAT5. Following the screening, we identified the targets, active components, and key pathways associated with YWD osteoporosis prevention. Most of these key targets and pathways are associated with osteoporosis, but further experimental validation is required.

The associations of alcoholic liver disease and nonalcoholic fatty liver disease with bone mineral density and the mediation of serum 25-Hydroxyvitamin D: A bidirectional and two-step Mendelian randomization.

BACKGROUND: Reduced bone mineral density (BMD) and osteoporosis are common in chronic liver diseases. However, the causal effect of alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) on BMD remains uncertain. OBJECTIVES: This study uses a two-sample Mendelian randomization (MR) design to evaluate the genetically predicted effect of ALD and NAFLD on BMDs using summary data from publically available genome-wide association studies (GWASs). METHODS: The GWAS summary statistics of ALD (1416 cases and 213,592 controls) and NAFLD (894 cases and 217,898 controls) were obtained from the FinnGen consortium. BMDs of four sites (total body, n = 56,284; femoral neck, n = 32,735; lumbar spine, n = 28,498; forearm, n = 8143) were from the GEnetic Factors for OSteoporosis Consortium. Data for alcohol consumption (n = 112,117) and smoking (n = 33,299) and serum 25-Hydroxyvitamin D (25-OHD) level (n = 417,580) were from UK-biobank. We first performed univariate MR analysis with the Inverse Variance Weighted (IVW) method as the primary analysis to investigate the genetically predicted effect of ALD or NAFLD on BMD. Then, multivariate MR and mediation analysis were performed to identify whether the effect was mediated by alcohol consumption, smoking, or serum 25-OHD level. RESULTS: The MR results suggested a robust genetically predicted effect of ALD on reduced BMD in the femoral neck (FN-BMD) (IVW beta = -0.0288; 95% CI: -0.0488, -0.00871; P = 0.00494) but not the other three sites. Serum 25-OHD level exhibited a significant mediating effect on the association between ALD and reduced FN-BMD albeit the proportion of mediation was mild (2.21%). No significant effects of NAFLD, alcohol consumption, or smoking on BMD in four sites, or reverse effect of BMD on ALD or NAFLD were detected. CONCLUSION: Our findings confirm the genetically predicted effect of ALD on reduced FN-BMD, and highlight the importance of periodic BMD and serum 25-OHD monitoring and vitamin D supplementation as needed in patients with ALD. Future research is required to validate our results and investigate the probable underlying mechanisms.

Differences in bone microarchitecture between genetic and secondary iron-overload mouse models suggest a role for hepcidin deficiency in iron-related osteoporosis.

Iron overload is one of the secondary osteoporosis etiologies. Cellular and molecular mechanisms involved in iron-related osteoporosis are not fully understood. AIM: The aim of the study was to investigate the respective roles of iron excess and hepcidin, the systemic iron regulator, in the development of iron-related osteoporosis. MATERIAL AND METHODS: We used mice models with genetic iron overload (GIO) related to hepcidin deficiency (Hfe-/- and Bmp6-/- ) and secondary iron overload (SIO) exhibiting a hepcidin increase secondary to iron excess. Iron concentration and transferrin saturation levels were evaluated in serum and hepatic, spleen, and bone iron concentrations were assessed by ICP-MS and Perl's staining. Gene expression was evaluated by quantitative RT-PCR. Bone micro-architecture was evaluated by micro-CT. The osteoblastic MC3T3 murine cells that are able to mineralize were exposed to iron and/or hepcidin. RESULTS: Despite an increase of bone iron concentration in all overloaded mice models, bone volume/total volume (BV/TV) and trabecular thickness (Tb.Th) only decreased significantly in GIO, at 12 months for Hfe-/- and from 6 months for Bmp6-/- . Alterations in bone microarchitecture in the Bmp6-/- model were positively correlated with hepcidin levels (BV/TV (ρ = +.481, p < .05) and Tb.Th (ρ = +.690, p < .05). Iron deposits were detected in the bone trabeculae of Hfe-/- and Bmp6-/- mice, while iron deposits were mainly visible in bone marrow macrophages in secondary iron overload. In cell cultures, ferric ammonium citrate exposure abolished the mineralization process for concentrations above 5 µM, with a parallel decrease in osteocalcin, collagen 1, and alkaline phosphatase mRNA levels. Hepcidin supplementation of cells had a rescue effect on the collagen 1 and alkaline phosphatase expression level decrease. CONCLUSION: Together, these data suggest that iron in excess alone is not sufficient to induce osteoporosis and that low hepcidin levels also contribute to the development of osteoporosis.

Mendelian randomization to evaluate the causal relationship between liver enzymes and the risk of six specific bone and joint-related diseases.

Background: Studies of liver dysfunction in relation to bone and joint-related diseases are scarce, and its causality remains unclear. Our objective was to investigate whether serum liver enzymes are causally associated with bone and joint-related diseases using Mendelian randomization (MR) designs. Methods: Genetic data on serum liver enzymes (alkaline phosphatase (ALP); alanine transaminase (ALT); gamma-glutamyl transferase (GGT)) and six common bone and joint-related diseases (rheumatoid arthritis (RA), osteoporosis, osteoarthritis (OA), ankylosing spondylitis, psoriatic arthritis, and gout) were derived from independent genome-wide association studies of European ancestry. The inverse variance-weighted (IVW) method was applied for the main causal estimate. Complementary sensitivity analyses and reverse causal analyses were utilized to confirm the robustness of the results. Results: Using the IVW method, the positive causality between ALP and the risk of osteoporosis diagnosed by bone mineral density (BMD) at different sites was indicated (femoral neck, lumbar spine, and total body BMD, odds ratio (OR) [95% CI], 0.40 [0.23-0.69], 0.35 [0.19-0.67], and 0.33 [0.22-0.51], respectively). ALP was also linked to a higher risk of RA (OR [95% CI], 6.26 [1.69-23.51]). Evidence of potential harmful effects of higher levels of ALT on the risk of hip and knee OA was acquired (OR [95% CI], 2.48 [1.39-4.41] and 3.07 [1.49-6.30], respectively). No causal relationship was observed between GGT and these bone and joint-related diseases. The study also found that BMD were all negatively linked to ALP levels (OR [95% CI] for TBMD, FN-BMD, and LS-BMD: 0.993 [0.991-0.995], 0.993 [0.988-0.998], and 0.993 [0.989, 0.998], respectively) in the reverse causal analysis. The results were replicated via sensitivity analysis in the validation process. Conclusions: Our study revealed a significant association between liver function and bone and joint-related diseases.

Role of lifestyle factors in mediating the effect of educational attainment on bone mineral density: a Mendelian randomization study.

We performed two-step multivariable Mendelian randomization analysis to explore the mediating role of lifestyle factors in educational attainment (EA) and bone mineral density (BMD). Summary statistics from genome-wide association studies of European lineages were used. Coffee intake and processed-meat intake mediated the association between EA and BMD. PURPOSE: This study aimed to explore the causal relationship between educational attainment (EA) and bone mineral density (BMD), as well as the potential mediating roles of lifestyle factors in the expected EA-BMD relationship. By identifying modifiable lifestyle factors, we hope to provide relevant information to prevent osteoporosis or low BMD in the less educated population. METHODS: Using summary statistics from genome-wide association studies (GWAS) of major European lineages, one- and two-sample Mendelian randomization (MR) analyses were performed to estimate the association between EA (in the social sciences genetic association consortium (SSGAC) involving 766,345 individuals and in the UK Biobank (UKB) involving 293,723 individuals) and BMD (in the Genetic Factors for Osteoporosis Consortium involving 426,824 individuals selected from the UKB). The EA variable in both consortia were expressed by years of schooling completed. Two-step multivariable MR was used to assess the mediating roles of eight lifestyle-related factors (moderate-to-vigorous physical activity, watching television, computer using, smoking initiation, coffee intake, alcohol intake frequency, tea intake, and processed-meat intake) in the EA and BMD association, and the corresponding mediating proportion was calculated. Meta-analysis was used to present a pooled estimate. RESULTS: A total of 317 and 73 independent single-nucleotide polymorphisms (SNPs) of GWAS significance (P < 5.0 × 10-8) were selected as instrumental variables (IVs) for EA in the SSGAC and UKB, respectively. A total of 513 SNPs were selected as IVs for the BMD. The results of one- and two-sample MR revealed that the genetically predicted BMD increased by 0.094 and 0.047 g/cm2, respectively, in response to each SD increment of genetically predicted schooling years. Among the eight candidate mediators, coffee intake and processed-meat intake were potential mediators revealed by the two-step multivariable MR analysis, mediating 26.87% and 23.92% of EA's effect on BMD, respectively. Meta-analysis showed consistent findings. Results of sensitivity analysis indicated the robustness of our findings. CONCLUSION: We elucidated the causal protective effect of EA on BMD and the mediating roles of coffee intake and processed-meat intake. Intervening with these factors can potentially reduce the burden of bone density loss or osteoporotic fractures among the less educated population.

Transcriptomic analysis the mechanisms of anti-osteoporosis of desert-living Cistanche herb in ovariectomized rats of postmenopausal osteoporosis.

Desert-living Cistanche herb (DC), as a traditional Chinese medicine for tonifying kidney yang, is often used to treat postmenopausal osteoporosis (PMOP). Total phenylethanoid glycosides are instruction ingredients for discrimination and assay according to the China pharmacopoeia for DC. This research aimed to reveal the anti-osteoporosis mechanism of total phenylethanoid glycosides of DC (PGC) by transcriptomic analysis of ovariectomized rats. Serum levels of BGP were evaluated by ELISA, the bone weight was measured, and transmission electron microscopy was used to examine the ultrastructure of osteoblasts in rats. In addition, micro-CT was used to detect the bone volume (Tb.BS/BV), bone mineral density (Tb.BMD), and bone mineral content (Tb.BMC) in trabecular bone, and the ratio of cortical bone area to total area (Ct.ar/Tt.ar), and the level of bone mineral content (Ct.BMC) in cortical bone. Differential expressed genes (DEGs) after PGC treatment were analyzed by transcriptomics. Then, a bioinformatics analysis of DEGs was carried out through GO enrichment, KEGG enrichment, and selection of the nucleus gene through the protein-protein interaction network. Through qRT-PCR analysis, the DEGs were verified. The analysis results indicated that PGC increased the secretion of osteogenic markers, and ultrastructural characterization of osteoblasts and bone morphology were improved in ovariectomized rats. A total of 269 genes were differentially expressed, including 201 genes that were downregulated and 68 genes that were upregulated between the model group and the PGC group. Bioinformation analysis results prompt the conclusion that PGC could promote the bone metabolism by muscle cell development, myofibril assembly, etc. In addition, our study also found that PGC has a good effect on osteoporosis complicated with cardiomyopathy, and it also provided evidence for the correlation between sarcopenia and osteoporosis.

Icariin promotes the proliferation and osteogenic differentiation of bone-derived mesenchymal stem cells in patients with osteoporosis and T2DM by upregulating GLI-1.

BACKGROUND: The function of mesenchymal stem cells (MSCs) from patients with osteoporosis (OP) is impaired and worsens in patients with type 2 diabetes mellitus (T2DM). Icariin (ICA) is the major active flavonoid glucoside isolated from traditional Chinese herbal Epimedium pubescens, and confirmed able to improve bone mass of OP patients. OBJECTIVE: To investigate the effect of ICA on the proliferation and osteogenic differentiation of bone-derived MSCs (BMSCs) from patients with OP and T2DM and uncover the potential mechanism. METHODS: BMSCs were treated with ICA, and proliferation and osteogenic potency were evaluated using the 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and detection of osteogenic markers (ALP, RUNX2, SPP1, COL1A1, and mineralized nodules) was performed. RNA sequencing and bioinformatic analysis were performed to identify differentially expressed genes (DEGs) after ICA treatment and screen proliferation- and osteogenic differentiation-related processes. Gene gain and loss were performed to confirm the role of the key candidate gene. RESULTS: ICA significantly promoted the proliferation and osteogenic differentiation of BMSCs. A total of 173 DEGs were identified after ICA treatment. Six DEGs (GLI-1, IGF2, BMP6, WNT5A, PTHLH, and MAPK14) enriched in both proliferation- and osteogenic differentiation-related processes were screened; GLI-1 had the highest validated |log2FC| value. Overexpression of GLI-1 enhanced the proliferation and osteogenic differentiation of BMSCs, and knockdown of GLI-1 weakened the positive effect of ICA on BMSCs. CONCLUSION: ICA promoted the proliferation and osteogenic differentiation of impaired BMSCs by upregulating GLI-1.

The genetically predicted causal relationship of inflammatory bowel disease with bone mineral density and osteoporosis: evidence from two-sample Mendelian randomization.

Background: Many existing studies indicated that patients with inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), tend to have the risk of low total body bone mineral density (BMD), and are more likely to have osteoporosis (OS). To determine the causal relationship between IBD and bone metabolic disorders, we herein performed a two-sample Mendelian randomization analysis (TSMR) using publicly available summary statistics. Methods: Summary statistics of total body BMD, OS and IBD were downloaded from the Open Genome-Wide Association Study (GWAS), FinnGen consortium and International Inflammatory Bowel Disease Genetics Consortium (IIBDGC). The European and East Asian populations have consisted in this Mendelian Randomization (MR) work. A range of quality control procedures were taken to select eligible instrument SNPs closely associated with total body BMD, OS and IBD. To make the conclusions more reliable, we applied five robust analytical methods, among which the inverse variance weighting (IVW) method acted as the major method. Besides, heterogeneity, pleiotropy and sensitivity were evaluated. Results: In the European population, the genetic association of UC on total body BMD (OR=0.97, 95%CI=0.96,0.99, P<0.001) and overall IBD on total body BMD (OR=0.98, 95%CI=0.97,1.00, P=0.013) were significant, while the effect of CD on total body BMD was not significant enough (OR=0.99, 95%CI=0.98,1.00, P=0.085). All of UC, CD and overall IBD can be the genetic risk factor of having OS with pathological fracture (UC: OR=1.13, 95%CI=1.02,1.26, P=0.024, CD: OR=1.14, 95%CI=1.05,1.25, P=0.003, overall IBD: OR=1.13, 95%CI=1.02,1.24, P=0.015). In East Asian groups, only CD had a causal relationship with OS (OR=1.04, 95% CI=1.01,1.07, P=0.019). Conclusion: Our study revealed genetically predicted associations between IBD on total body BMD and OS in European and East Asian populations. This work supplemented the results of previous retrospective studies and demonstrated the necessity of BMD monitoring in patients with IBD.

A study on the anti-osteoporosis mechanism of isopsoralen based on network pharmacology and molecular experiments.

OBJECTIVE: Osteoporosis (OP) is a disease caused by multiple factors. Studies have pointed out that isopsoralen (IPRN) is one of the most effective drugs for the treatment of OP. Based on network pharmacological and molecular experimental analysis, the molecular mechanism of IPRN in osteoporosis is clarified. METHODS: IPRN target genes and OP-related genes were predicted from the databases. Intersections were obtained and visualized. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on target genes, which was confirmed by experiments internal and external experiments. Molecular docking was used to verify the binding between IPRN and target proteins. Molecular dynamics (MD) simulates the binding affinity of protein targets and active compounds. RESULTS: 87 IPRN target genes and 242 disease-related targets were predicted. The protein-protein interaction (PPI) network identified 18 IPRN target proteins for the treatment of OP. GO analysis indicated that target genes were involved in biological processes. KEGG analysis showed that pathways such as PI3K/AKT/mTOR were associated with OP. Cell experiments (qPCR and WB) found that the expressions of PI3K, AKT, and mTOR in MC3T3-E1 cells at 10 µM, 20 µM, and 50 µM IPRN concentrations, especially at 20 µM IPRN treatment, were higher than those in the control group at 48 h. Animal experiments also showed that compared with the control group, 40 mg/kg/time IPRN could promote the expression of the PI3K gene in chondrocytes of SD rats. CONCLUSIONS: This study predicted the target genes of IPRN in the treatment of OP and preliminarily verified that IPRN plays an anti-OP role through the PI3K/AKT/mTOR pathway, which provides a new drug for the treatment of OP.

Lack of causal association between heart failure and osteoporosis: a Mendelian randomization study.

OBJECTIVES: Heart failure (HF) has been implicated in osteoporosis. However, causality remains unestablished. Here, we sought to assess causal associations of genetic liability to HF with osteoporosis using Mendelian randomization (MR) analyses. METHODS: Independent single nucleotide polymorphisms associated with HF at genome-wide significance were derived from a large genome-wide association study (GWAS) (including up to 977,323 individuals). We obtained summary statistics for forearm (FA) bone mineral density (BMD) (n = 8,143), femoral neck (FN) BMD (n = 32,735), lumbar spine (LS) BMD (n = 28,498), heel (HE) BMD (n = 426,824), and fracture (n = 1,214,434) from other GWAS meta-analyses. Inverse variance weighted (IVW) and several supplementary methods were performed to calculate the MR estimates. RESULTS: Genetically determined HF has no causal effect on FA-BMD (odds ratio (OR) 1.17; 95% confidence interval (CI) 0.82, 1.66; P = 0.389), FN-BMD (OR 1.01; 95% CI 0.85, 1.19; P = 0.936), LS-BMD (OR 0.96; 95% CI 0.80, 1.17; P = 0.705), HE-BMD (OR 1.01; 95% CI 0.90, 1.13; P = 0.884), and fracture risk (OR 1.00; 95% CI 0.92, 1.10; P = 0.927). Complementary analyses returned broadly consistent results. CONCLUSION: This MR study provides genetic evidence that HF may not lead to an increased risk of reduced BMDs or fracture.