Sesamin stimulates osteoblast differentiation through p38 and ERK1/2 MAPK signaling pathways

Daily supplement of sesame oil prevents postmenopausal osteoporosis via maintaining serum estrogen and aromatase levels in rats

Estrogen deficiency is one of the main causes of postmenopausal osteoporosis in elderly women. Hormone replacement therapy has been employed to manage postmenopausal osteoporosis; however, it has raised concerns related to heart attacks and breast cancer. Sesame oil has been reported to affect sex hormone status. The aim of the present study is to evaluate the effect of sesame oil supplement on postmenopausal osteoporosis in rats. We used female Sprague Dawley rats that underwent bilaterally ovariectomy (OVX) as an experimental postmenopausal osteoporosis animal model. These rats were orally administrated sesame oil (0.25 or 0.5 mL/kg/day) for four months as the therapeutic group. We assessed bone mineral density (BMD) and the levels of osteocalcin, procollagen-I C-terminal propeptide (PICP), collagen cross-linked N-telopeptide (NTx), estradiol, and aromatase in the sera. The daily supplementation of sesame oil significantly increased BMD, serum osteocalcin levels, and trabecular areas in the OVX-treated rats. Sesame oil also elevated serum PICP levels and decreased NTx levels in these rats. Furthermore, sesame oil effectively maintained serum estradiol and aromatase levels in the OVX-induced osteoporosis rats. In conclusion, daily supplementation of sesame oil prevents postmenopausal osteoporosis by maintaining serum estrogen and aromatase levels, while also modulating the imbalance between bone formation and resorption in osteoporosis rats.

Sesamin inhibits RANKL-induced osteoclastogenesis and attenuates LPS-induced osteolysis via suppression of ERK and NF-κB signalling pathways

Infection by bacterial products in the implant and endotoxin introduced by wear particles activate immune cells, enhance pro-inflammatory cytokines production, and ultimately promote osteoclast recruitment and activity. These factors are known to play an important role in osteolysis as well as potential targets for the treatment of osteolysis. Sesamin has been shown to have a variety of biological functions, such as inhibiting inflammation, anti-tumour and involvement in the regulation of fatty acid and cholesterol metabolism. However, the therapeutic effect of sesamin on osteolysis and its mechanism remain unclear. Present studies shown that in the condition of in vitro, sesamin could inhibit osteoclastogenesis and bone resorption, as well as suppressing the expression of osteoclast-specific genes. Further studies on the mechanism suggest that the effect of sesamin on human osteoclasts was mediated by blocking the ERK and NF-κB signalling pathways. Besides, sesamin was found to be effective in treating LPS-induced osteolysis by decreasing the production of pro-inflammatory cytokines and inhibiting osteoclastogenesis in vivo. Sesamin was non-toxic to heart, liver, kidney, lung and spleen. Therefore, sesamin is a promising phytochemical agent for the therapy of osteolysis-related diseases caused by inflammation and excessive osteoclast activation.

The What and Who of Dietary Lignans in Human Health: Special Attention to Estrogen Effects and Safety Evaluation

Lignans are a group of phenolic compounds found in plant-based diets. The human body can obtain lignans through diet, which are then metabolized into enterolignans. The enterolignans have been linked to several health benefits, including anticancer, anti-inflammatory, antioxidant effects, and estrogen effects. This review explores the relationship between the estrogenic effects of lignans and health. This review not only considers the estrogen-like activity of lignans but also discusses the safe dosage of lignans at different life stages. In addition, this review also identified other types of bioactive compounds that can act synergistically with lignans to promote health. Studies have shown that lignan administration during pregnancy and lactation reduces the risk of breast cancer in offspring. Further studies are needed to investigate the estrogenic safety effects of lignan on pregnant women and children. Whether lignans combine with other nutrients in complex food substrates to produce synergistic effects remains to be investigated. This review provides a basis for future studies on the safe dose of lignan and recommended dietary intake of lignan. We believe that the acquired as discussed here has implications for developing dietary therapies that can promote host nutrition and modulate estrogenic diseases.

Electroacupuncture stimulating Zusanli (ST36), Sanyinjiao (SP6) in mice with collagen-induced arthritis leads to adenosine A2A receptor-mediated alteration of p38α mitogen-activated protein kinase signaling and inhibition of osteoclastogenesis

OBJECTIVE

To observe the effect of electroacupuncture (EA) stimulating Zusanli (ST36), Sanyinjiao (SP6) on inhibition of osteoclastogenesis and the role of the adenosine A2A receptor (A2AR) and the p38α Mitogen-Activated Protein Kinase (MAPK) signaling pathway in mediating this effect.

METHODS

Mice with collagen induced arthritis (CIA) received different treatments. Immunohistochemistry and western blotting were used to determine the levels of multiple signaling molecules in these joints [receptor activator of nuclear transcription factor-κB (NF-κB) ligand (RANKL), receptor activator of NF-κB (RANK), tumor necrosis factor receptor associated factor 6 (TRAF6), p38α, NF-κB, and nuclear factor of activated T cells C1 (NFATc1)]. Osteoclasts were identified using tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

The immunohistochemistry results indicated upregulation of p38α, NF-κB, and NFATc1 in the CIA-control and CIA-EA-SCH58261 groups, but reduced levels in the CIA-EA group. Western blotting indicated upregulation of RANKL, RANK, TRAF6, p38α, NF-κB, and NFATc1 in the CIA-control and CIA-EA-SCH58261 groups, but reduced expression in the CIA-EA group. Osteoclasts were more abundant in the CIA-control and CIA-EA-SCH58261 groups than in the CIA-EA group.

CONCLUSIONS

EA treatment enhanced the A2AR activity and inhibited osteoclast formation by inhibition of RANKL, RANK, TRAF6, p38α, NF-κB, and NFATc1. SCH58261 reversed the effect of EA. These results suggest that EA regulated p38α-MAPK signaling by increasing A2AR activity, which inhibited osteoclastogenesis.

Human Mesenchymal Stem Cells-Derived Exosome Mimetic Vesicles Regulation of the MAPK Pathway and ROS Levels Inhibits Glucocorticoid-Induced Apoptosis in Osteoblasts

Background

Long-term extensive use of glucocorticoids will lead to hormonal necrosis of the femoral head, and osteoblasts play an important role in the prevention of osteonecrosis. However, there is no complete cure for necrosis of the femoral head. Mesenchymal stem cell- (MSCs-) derived exosomes are widely used for the repair of various tissue lesions. Therefore, the aim of this study was to investigate the mechanism of dexamethasone- (DEX-) induced osteoblast apoptosis and the therapeutic effect of human umbilical cord MSC- (hucMSC-) derived exosome mimetic vesicles (EMVs) on osteoblast-induced apoptosis by DEX.

Methods

The viability and apoptosis of primary MC3T3-E1 cells were determined by the Cell Counting Kit-8 (CCK-8), FITC-Annexin V/PI staining and immunoblot. The intracellular levels of reactive oxygen species (ROS) after DEX treatment were measured by 2', 7' -dichlorodihydrofluorescein diacetate (DCFH-DA) staining. In this study, hucMSC-EMVs and N-acetyl-l-cysteine (NAC) were used as therapeutic measures. The expression of B-cell lymphoma 2-associated X, Bcl 2, HO-1, and nuclear factor erythroid-derived 2-like 2 and MAPK- signaling pathway in osteogenic cell MC3T3-E1 cells treated with Dex was analyzed by the immunoblotting.

Results

DEX significantly induced osteoblasts MC3T3-E1 apoptosis and ROS accumulation. MAPK-signaling pathway was activated in MC3T3-E1 after DEX treatment. hucMSC-EMVs intervention significantly downregulated DEX-induced MAPK-signaling pathway activation and ROS accumulation. In addition, hucMSC-EMVs can reduce the apoptosis levels in osteoblast MC3T3-E1 cells induced by DEX.

Conclusions

Our study confirmed that hucMSC-EMVs regulates MAPK-signaling pathway and ROS levels to inhibit DEX-induced osteoblast apoptosis.

The Effect of Apple-Derived Nanovesicles on the Osteoblastogenesis of Osteoblastic MC3T3-E1 Cells

Osteoporosis is characterized by low bone mass and elevated structural deterioration of the bone tissue, resulting in bone weakness with an increased risk of fracture. Considering biological activities of various phytochemicals extracted from apples, we herein demonstrated the potential antiosteoporotic effects of apple-derived nanovesicles (apple NVs) using osteoblastic MC3T3-E1 cells. Apple NVs significantly stimulated the growth of MC3T3-E1 cells. The cellular alkaline phosphatase (ALP) activity was significantly upregulated in the 5 μg/mL apple NVs-treated group. In addition, the concentrarion of mineralized nodules was significantly increased in the apple NVs-treated groups. Furthermore, apple NVs increased the expression of the genes and proteins associated with osteoblast growth and differentiation, such as Runx2, ALP, OPN, and BMP2/4, which further activated ERK- and JNK-related mitogen-activated protein kinase signaling. These results demonstrate that apple NVs have a potential to prevent osteoporosis by promoting osteoblastogenesis in osteoblastic MC3T3-E1 cells through regulating the BMP2/Smad1 pathways.

Zoledronate promotes osteoblast differentiation in high-glucose conditions via the p38MAPK pathway

Zoledronate (ZOL) were found to inhibit bone resorption in an animal model of diabetes, high glucose concentrations have been shown to decreased the osteogenesis-related gene expression. But the molecular mechanism by which high glucose levels affect osteoblasts and the effects of ZOL on osteoblast differentiation in a high-glucose environment remain unclear. Therefore, we aimed to investigate the effect of ZOL on osteoblast differentiation in a high-glucose environment and determine the responsible mechanism. Cell proliferation was detected by MTT assay, and cell differentiation was evaluated by immunofluorescence staining for alkaline phosphatase expression, alizarin red staining, cytoskeletal arrangement, and actin fiber formation. Real-time PCR and western blot analyses were performed to detect the mRNA and protein expression of p38MAPK, phosphorylated (p)-p38MAPK, CREB, p-CREB, collagen (COL) I, osteoprotegerin (OPG), and RANKL. The results showed that cell proliferation activity did not differ among the groups. But high glucose inhibited osteoblast differentiation; actin fiber formation; and p38MAPK, p-p38MAPK, CREB, p-CREB, COL I, and OPG expression, while promoting RANKL expression. However, we found that treatment with ZOL reversed these effects of high glucose. And further addition of a p38MAPK inhibitor led to inhibition of osteoblast differentiation and actin fiber formation, and lower p38MAPK, p-p38MAPK, CREB, p-CREB, COL I, and OPG expression than in the high glucose +ZOL group with higher RANKL expression than in the high glucose +ZOL group. Collectively, this study demonstrates that high glucose inhibits the differentiation of osteoblasts, and ZOL could partly overcome these effects by regulating p38MAPK pathway activity.

Synergistic Effect of Sesamin and γ-Tocotrienol on Promoting Osteoblast Differentiation via AMPK Signaling

Background: Sesamin is a rich phytochemical found in sesame seed oil that can promote osteoblast differentiation of rat BMSCs and improve rat bone structure by regulating Wnt/-Catenin pathway. Combined sesamin and γ-Tocotrienol (γ-T3) have been clarified to inhibit the proliferation of breast cancer cells, but their role in osteoporosis has not been explored. This paper aimed to discuss the synergistic effect of sesamin and γ-T3 in osteoporosis and disclose the underlying mechanism.

Materials and methods: CCK-8 assay was to appraise the proliferation of hBMSCs after treated with sesamin and γ-T3. Moreover, the proteins in AMPK signaling in osteoblasts pretreated with AMPK inhibitor compound C (CC) were detected after the induction of sesamin and γ-T3. Then, CCK-8, ALP assay and ARS staining were used to analyze whether the proliferation and osteoblast differentiation of hBMSCs was via APMK pathway. RT-qPCR and western blot were conducted to quantify the levels of markers in osteoblasts.

Results: It was determined that 5 g/mL sesamin and 1 μM γ-T3 exerted obvious influences on the viability of hBMSCs. Moreover, the co-treatment of sesamin and γ-T3 elevated the protein levels of related factors in AMPK pathway, which was reversed by CC. Furthermore, The proliferation and osteoblast differentiation exhibited remarkable increments upon exposure to both sesamin and γ-T3, whereas CC abolished these effects.

Conclusion: In conclusion, the present study presented the first line of evidence to verify the synergystic effects of sesamin and γ-T3 on alleviating osteoporosis, and revealed their effects were realized by modulating the AMPK pathway. This paper has indicated the great potential of combined sesamin and γ-T3 in osteoporosis treatment.

DANCR Mediates the Rescuing Effects of Sesamin on Postmenopausal Osteoporosis Treatment via Orchestrating Osteogenesis and Osteoclastogenesis

As one of the leading causes of bone fracture in postmenopausal women and in older men, osteoporosis worldwide is attracting more attention in recent decades. Osteoporosis is a common disease mainly resulting from an imbalance of bone formation and bone resorption. Pharmaceutically active compounds that both activate osteogenesis, while repressing osteoclastogenesis hold the potential of being therapeutic medications for osteoporosis treatment. In the present study, sesamin, a bioactive ingredient derived from the seed of Sesamum Indicum, was screened out from a bioactive compound library and shown to exhibit dual-regulating functions on these two processes. Sesamin was demonstrated to promote osteogenesis by upregulating Wnt/β-catenin, while repressing osteoclastogenesis via downregulating NF-κB signaling . Furthermore, DANCR was found to be the key regulator in sesamin-mediated bone formation and resorption . In an ovariectomy (OVX)-induced osteoporotic mouse model, sesamin could rescue OVX-induced bone loss and impairment. The increased serum level of DANCR caused by OVX was also downregulated upon sesamin treatment. In conclusion, our results demonstrate that sesamin plays a dual-functional role in both osteogenesis activation and osteoclastogenesis de-activation in a DANCR-dependent manner, suggesting that it may be a possible medication candidate for osteoporotic patients with elevated DNACR expression levels.

Integrating genome-wide association and transcriptome prediction model identifies novel target genes for osteoporosis

In this study, we integrated large-scale GWAS summary data and used the predicted transcriptome-wide association study method to discover novel genes associated with osteoporosis. We identified 204 candidate genes, which provide novel clues for understanding the genetic mechanism of osteoporosis and indicate potential therapeutic targets.

INTRODUCTION

Osteoporosis is a highly polygenetic disease characterized by low bone mass and deterioration of the bone microarchitecture. Our objective was to discover novel candidate genes associated with osteoporosis.

METHODS

To identify potential causal genes of the associated loci, we investigated trait-gene expression associations using the transcriptome-wide association study (TWAS) method. This method directly imputes gene expression effects from genome-wide association study (GWAS) data using a statistical prediction model trained on GTEx reference transcriptome data. We then performed a colocalization analysis to evaluate the posterior probability of biological patterns: associations characterized by a single causal variant or multiple distinct causal variants. Finally, a functional enrichment analysis of gene sets was performed using the VarElect and CluePedia tools, which assess the causal relationships between genes and a disease and search for potential gene's functional pathways. The osteoporosis-associated genes were further confirmed based on the differentially expressed genes profiled from mRNA expression data of bone tissue.

RESULTS

Our analysis identified 204 candidate genes, including 154 genes that have been previously associated with osteoporosis, 50 genes that have not been previously discovered. A biological function analysis found that 20 of the candidate genes were directly associated with osteoporosis. Further analysis of multiple gene expression profiles showed that 15 genes were differentially expressed in patients with osteoporosis. Among these, SLC11A2, MAP2K5, NFATC4, and HSP90B1 were enriched in four pathways, namely, mineral absorption pathway, MAPK signaling pathway, Wnt signaling pathway, and PI3K-Akt signaling pathway, which indicates a causal relationship with the occurrence of osteoporosis.

CONCLUSIONS

We demonstrated that transcriptome fine-mapping identifies more osteoporosis-related genes and provides key insight into the development of novel targeted therapeutics for the treatment of osteoporosis.

CRISPR-Cas9-Mediated Genome Editing Confirms EPDR1 as an Effector Gene at the BMD GWAS-Implicated 'STARD3NL' Locus

Genome-wide-association studies (GWASs) have discovered genetic signals robustly associated with BMD, but typically not the precise localization of effector genes. By intersecting genome-wide promoter-focused Capture C and assay for transposase-accessible chromatin using sequencing (ATAC-seq) data generated in human mesenchymal progenitor cell (hMSC)-derived osteoblasts, consistent contacts were previously predicted between the EPDR1 promoter and multiple BMD-associated candidate causal variants at the 'STARD3NL' locus. RNAi knockdown of EPDR1 expression in hMSC-derived osteoblasts was shown to lead to inhibition of osteoblastogenesis. To fully characterize the physical connection between these putative noncoding causal variants at this locus and the EPDR1 gene, clustered regularly interspaced short-palindromic repeat Cas9 endonuclease (CRISPR-Cas9) genome editing was conducted in hFOB1.19 cells across the single open-chromatin region harboring candidates for the underlying causal variant, rs1524068, rs6975644, and rs940347, all in close proximity to each other. RT-qPCR and immunoblotting revealed dramatic and consistent downregulation of EPDR1 specifically in the edited differentiated osteoblast cells. Consistent with EPDR1 expression changes, alkaline phosphatase staining was also markedly reduced in the edited differentiated cells. Collectively, CRISPR-Cas9 genome editing in the hFOB1.19 cell model supports previous observations, where this regulatory region harboring GWAS-implicated variation operates through direct long-distance physical contact, further implicating a key role for EPDR1 in osteoblastogenesis and BMD determination. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Cytochalasin D Promotes Osteogenic Differentiation of MC3T3-E1 Cells via p38-MAPK Signaling Pathway

BACKGROUND

Bone defect caused by trauma, tumor resection, infection or congenital malformation is a common clinical disease. Bone tissue engineering is regarded as a promising way of bone defect reconstruction. Thus, agents that can promote osteogenesis have received great attention. Cytochalasin D (Cyto D), a metabolite derived from molds, proves to be able to modify actin, reorganize cytoskeleton, and then promote the osteogenic differentiation.

OBJECTIVE

The purpose of this study was to explore the effect and mechanism of Cyto D on osteogenic differentiation of mouse pre-osteoblast MC3T3-E1 cells.

METHODS

The optimum concentration of Cyto D was explored. The osteogenic differentiation of MC3T3-E1 cells induced by Cyto D was assessed by alkaline phosphatase (ALP) staining, Alizarin Red S (ARS) staining, western blotting and quantitative real-time polymerase chain reaction (RT-qPCR). In addition, a specific pathway inhibitor was utilized to explore whether MAPK pathways were involved in this process.

RESULTS

The results showed that the optimized concentration of action was 10-2µg/ml. The expression of Runx2, OCN and OSX was up-regulated by the supplement of Cyto D. ALP activity, calcium deposition, and phosphorylation level of p38 protein were also improved. Inhibition of the pathway significantly reduced the activation of p38, and the expression of osteogenic-related genes.

CONCLUSION

Cyto D can promote the osteogenic differentiation of MC3T3 cells via the p38-MAPK signaling pathway, but not the ERK1/2 or JNK, and it is a potential agent to improve the osteogenesis of MC3T3 cells.

Anti-Osteoporotic Effects of Antioxidant Peptides PIISVYWK and FSVVPSPK from Mytilus edulis on Ovariectomized Mice

Numerous amounts of evidence suggest that bioactive peptides with diverse physiological activities can be nutraceuticals or potential drug candidates. In this study, blue mussel-derived antioxidant peptides PIISVYWK and FSVVPSPK were subjected to evaluate their osteogenic effect in mouse bone marrow mesenchymal stem cells (mBMMSCs) followed by an in vivo anti-osteoporotic effect. Treatment of PIISVYWK and FSVVPSPK on mBMMSCs stimulated alkaline phosphatase activity and calcification. Western blot results revealed that PIISVYWK and FSVVPSPK increased the expression of bone morphogenetic protein-2/4 (BMP-2/4) followed by upregulating p-Smad1/5, type I collagen, and transcription factors including Runx2 and osterix in mBMMSCs. Two peptides also activated the phosphorylation of MAPKs (p-p38, p-ERK, and p-JNK). Treatment of MAPK inhibitors significantly inhibited the BMP signaling pathway, indicating that PIISVYWK and FSVVPSPK stimulated osteoblast differentiation of mBMMSCs through the MAPK-dependent BMP signaling pathway. The anti-osteoporotic effect of PIISVYWK and FSVVPSPK in ovariectomized (OVX) mice was investigated. Treatment of PIISVYWK and FSVVPSPK for ten weeks showed a notable anti-osteoporotic effect in OVX mice via increasing bone mineral density and other bone parameters compared to OVX mice without peptides. Serum analysis also showed that treatment of PIISVYWK and FSVVPSPK completely reduced osteocalcin and ALP (alkAline phosphatase) activity. Taken together, these results suggest that PIISVYWK and FSVVPSPK could be health-promoting functional food ingredients against osteoporosis.

Simultaneous and rapid determination of sesamin and sesamolin in sesame oils using excitation-emission matrix fluorescence coupled with self-weighted alternating trilinear decomposition

BACKGROUND

Sesamin and sesamolin are two typical and important lignans isolated from sesame oil. Various studies have shown the bioactivity, physiological activity, and potential health benefits of the two components. In this study, a rapid method for the simultaneous determination of sesamin and sesamolin in sesame oils was proposed. The excitation-emission fluorescence spectra of the oils were obtained after a simple pretreatment, then self-weighted alternating trilinear decomposition was used to extract the quantitative information from the very overlapping spectra.

RESULTS

It was found that reasonable quantification results could be obtained with the limits of detection for the two lignans. These limits were 0.05 mg/g and 0.24 mg/g, and the limits of quantitation were 0.14 mg/g and 0.74 mg/g, respectively. The average recoveries for sesamin and sesamolin were 99.05% and 94.97%.

CONCLUSION

The results indicate that, with simple sample pretreatment, the application for combining excitation-emission fluorescence spectra and self-weighted alternating trilinear decomposition can be a useful and sensitive tool for the determination of lignans in sesame oil. © 2020 Society of Chemical Industry.

Butein Promotes Lineage Commitment of Bone Marrow-Derived Stem Cells into Osteoblasts via Modulating ERK1/2 Signaling Pathways

Butein is a phytochemical that belongs to the chalcone family of flavonoids and has antitumor, anti-inflammatory, and anti-osteoclastic bone resorption activities. This study aims to investigate the effects of butein on the differentiation potential of mouse primary bone marrow-derived mesenchymal stem cells (mBMSCs) into osteoblast and adipocyte lineages. Primary cultures of mBMSCs are treated with different doses of butein during its differentiation. Osteoblast differentiation is assessed by alkaline phosphatase (ALP) activity quantification and Alizarin red staining for matrix mineralization, while adipogenesis is assessed by quantification of lipid accumulation using Oil Red O staining. Osteoblastic and adipocytic gene expression markers are determined by quantitative real-time PCR (qPCR). Western blot analysis is used to study the activation of extracellular signal-regulated kinase (ERK1/2). Interestingly, butein promotes the lineage commitment of mBMSCs into osteoblasts, while suppressing their differentiation into adipocytes in a dose-dependent manner. A similar effect of butein is confirmed in human (h) primary BMSCs. Occurring at the molecular level, butein significantly upregulates the mRNA expression of osteoblast-related genes, while downregulating the expression of adipocyte-related genes. The mechanism of butein-induced osteogenesis is found to be mediated by activating the ERK1/2 signaling pathway. To conclude, we identify butein as a novel nutraceutical compound with an osteo-anabolic activity to promote the lineage commitment of BMSCs into osteoblast versus adipocyte. Thus, butein can be a plausible therapeutic drug for enhancing bone formation in osteoporotic patients.

Sesamum indicum L. Oil and Sesamin Induce Auditory-Protective Effects Through Changes in Hearing Loss-Related Gene Expression

Changing consumption patterns and increasing health awareness, especially in Europe, are resulting in an increased demand for sesame seeds. In 2016, Asia imported the highest quantity of sesame seeds, followed by Europe and North America. We examined, for the first time, the effects of treatment with sesame oil and sesamin in hearing impairment models. Sesame oil exhibited an ameliorative effect on auditory impairment in a hair cell line in zebrafish and mice. In ototoxic zebrafish larvae, neuromasts and otic cells increased in numbers because of sesame oil. Furthermore, auditory function in noise-induced hearing loss (NIHL) was studied through auditory brainstem response to evaluate the therapeutic effects of sesame oil. Sesame oil reduced the hearing threshold shift in response to clicks and 8, 16-kHz tone bursts in NIHL mice. Auditory-protective effect of sesame oil was seen in zebrafish and mice; therefore, we used chromatographic analysis to study sesamin, which is the major effective factor in sesame oil. To investigate its effects related to auditory function, we studied the hearing-related gene, Tecta, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) assay. Auditory cell proliferation was induced by treatment with sesame oil and sesamin using Tecta (Tectorin Alpha) regulation. The expression of Tecta increases in the apex area of the cochlear hair cells as they grow, and their activity is enhanced by sesame oil and sesamin. These results provide a novel mechanistic insight into the sesame oil activities and suggest that sesamin, the key constituent in sesame oil, is responsible for its auditory function related benefits, including protection of auditory cells and reversal of their impairments.

A Network Pharmacology Approach to Estimate the Active Ingredients and Potential Targets of Cuscutae semen in the Treatment of Osteoporosis

Background

Osteoporosis is a metabolic osteopathy characterized by abnormal bone mass and microstructure that has become a public health problem worldwide. Cuscutae semen (CS) is a traditional Chinese medicine (TCM) that has a positive effect on the prevention and treatment of osteoporosis. However, the mechanism of CS is unclear. Therefore, this study aimed to reveal the possible molecular mechanism involved in the effects of CS on osteoporosis based on a network pharmacology approach.

Material/Methods

The inactive and active ingredients of CS were identified by searching the pharmacology analysis platform of the Chinese medicine system (TCMSP), and the targets of osteoporosis were screened in the relevant databases, such as GeneCards, PubMed, and the Comparative Toxicogenomics Database (CTD). The network of “medicine-ingredients-disease-targets (M-I-D-T)” was established by means of network pharmacology, and the key targets and core pathways were determined by R analysis. Molecular docking methods were used to evaluate the binding activity between the target and the active ingredients of CS.

Results

Eleven active ingredients were identified in CS, and 175 potential targets of the active ingredients were also identified from the TCMSP. Moreover, we revealed 22 539 targets related to osteoporosis in the 3 well-established databases, and we determined the intersection of the disease targets and the potential targets of the active ingredients; 107 common targets were identified and used in further analysis. Additionally, biological processes and signaling pathways involved in target action, such as fluid shear stress, atherosclerosis, cancer pathways, and the TNF signaling pathway, were determined. Finally, we chose the top 5 common targets, CCND1, EGFR, IL6, MAPK8, and VEGFA, for molecular docking with the 11 active ingredients of CS.

Conclusions

This study suggested that CS has multiple ingredients and multiple targets relevant to the treatment of osteoporosis. We determined that the active ingredient, sesamin, may be the most crucial ingredient of CS for the treatment of osteoporosis. Additionally, the network pharmacology method provided a novel research approach to analyze the function of complex ingredients.

BMSC-derived exosomes carrying microRNA-122-5p promote proliferation of osteoblasts in osteonecrosis of the femoral head

Mesenchymal stem cells (MSCs) with multipotential differentiation capacity can differentiate into bone cells under specific conditions and can be used to treat osteonecrosis (ON) of the femoral head (ONFH) through cell transplantation. The current study aims to explore the role of bone marrow (BM) MSCs (BMSCs)-derived exosomes carrying microRNA-122-5p (miR-122-5p) in ONFH rabbit models.First, rabbit models with ONFH were established. ONFH-related miRNAs were screened using the Gene Expression Omnibus (GEO) database. A gain-of-function study was performed to investigate the effect of miR-122-5p on osteoblasts and BMSCs and effects of exosomes carrying miR-122-5p on ONFH. Co-culture experiments for osteoblasts and BMSCs were performed to examine the role of exosomal miR-122-5p in osteoblast proliferation and osteogenesis. The target relationship between miR-122-5p and Sprouty2 (SPRY2) was tested.MiR-122, significantly decreased in ONFH in the GSE89587 expression profile, was screened. MiR-122-5p negatively regulated SPRY2 and elevated the activity of receptor tyrosine kinase (RTK), thereby promoting the proliferation and differentiation of osteoblasts. In vivo experiments indicated that bone mineral density (BMD), trabecular bone volume (TBV), and mean trabecular plate thickness (MTPT) of femoral head were increased after over-expressing miR-122-5p in exosomes. Significant healing of necrotic femoral head was also observed.Exosomes carrying over-expressed miR-122-5p attenuated ONFH development by down-regulating SPRY2 via the RTK/Ras/mitogen-activated protein kinase (MAPK) signaling pathway. Findings in the present study may provide miR-122-5p as a novel biomarker for ONFH treatment.

Sesamin Promotes Osteoblastic Differentiation and Protects Rats from Osteoporosis

Background

Osteoporosis is a common osteopathy, resulting in fractures, especially in elder people. Sesamin has many pharmacological effects, including supplying calcium. However, how sesamin might prevent osteoporosis is still under study.

Material/Methods

Bone marrow stromal cells (BMSCs) extracted from rat femur were induced for osteoblastic differentiation. Cell proliferation, alkaline phosphatase (ALP), osterix (OSX), SRY-box 9 (SOX9), runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), β-catenin, low density lipoprotein receptor-related protein 5 (LRP5), and glycogen synthase kinase-3β (GSK-3β) levels in BMSCs were detected in the presence or absence of sesamin (1 μM or 10 μM). In addition, FH535 (1 μM) was used to silence Wnt/β-catenin in vitro. Ovariectomized (OVX) rats were established and intragastrically administrated sesamin (80 mg/kg), and then the rat bones were analyzed by micro-computed tomography. Osteocalcin and collagen type I were measured in the rat femurs.

Results

Sesamin had no influence on BMSC proliferation. Higher sesamin concentration promoted Wnt/β-catenin activity and enhanced more expressions of ALP, OSX, SOX9, RUNX2, and OCN, gradually and significantly (P<0.05). Silencing Wnt/β-catenin weakened the enhancement on RUNX2 and OCN expression. Sesamin (80 mg/kg) promoted bone structure in ovariectomized rats, and significantly enhanced osteocalcin and collage type I expression (P<0.05).

Conclusions

Sesamin promoted osteoblastic differentiation of rat BMSCs by regulating the Wnt/β-catenin pathway, and improved rat bone structure. Sesamin could have therapeutic and preventive effects on osteoporosis.

The interactions of dendritic cells with osteoblasts on titanium surfaces: an in vitro investigation

OBJECTIVES

Osteoimmune interactions possess a critical part in the integration of materials and hosts. Dendritic cells (DCs) are the most common members of osteoimmune cells family. The titanium surfaces of dental implants tend to promote a mature dendritic cell phenotype with increased proinflammatory secretion. However, very little is known to the effects of this microenvironment on the behaviors of cells around implants, especially osteoblasts, and how the tissue integrations take place on such biomaterial surfaces. Therefore, the present study was to investigate the interactions of DCs with osteoblasts on titanium surfaces. DCs seeded on PT and SLA titanium surfaces were compared by assays for the proliferations, surface markers, and inflammatory genes expressions.

MATERIALS AND METHODS

DCs seeded on PT and SLA titanium surfaces were compared by assays for the proliferations, surface markers, and inflammatory genes expressions. Next, we harvested the dendritic cell-conditioned medium (CM) and investigated the effects of CM on MC3T3-E1.

RESULTS

The results showed an increase in CD86 and proinflammatory expressions of DCs seeded on PT and SLA surfaces, as well as a decrease in anti-inflammatory cytokines. The CM from titanium surfaces inhibited the osteoblast differentiation with reduced expression of osteogenic genes RUNX2, COL1, ALP, and OCN and decreased ALP activity as well as Alizarin red staining.

CONCLUSION

These findings suggested that titanium surfaces switch DCs toward maturation phenotypes and thus inhibit the differentiation and mineralization of osteoblasts.

CLINICAL RELEVANCE

Knowing the significant impact of immune cells on osteogenesis behaviors, some efforts to decrease the immune reaction might be of clinical significance. Favorable immune environments can increase the dental implants survival rate in patients.

Vitamin C Activates Osteoblastogenesis and Inhibits Osteoclastogenesis via Wnt/β-Catenin/ATF4 Signaling Pathways

This study evaluated the effects of vitamin C on osteogenic differentiation and osteoclast formation, and the effects of vitamin C concentration on bone microstructure in ovariectomized (OVX) Wistar rats. Micro-computed tomography analysis revealed the recovery of bone mineral density and bone separation in OVX rats treated with vitamin C. Histomorphometrical analysis revealed improvements in the number of osteoblasts, osteoclasts, and osteocytes; the osteoblast and osteoclast surface per bone surface; and bone volume in vitamin C-treated OVX rats. The vitamin C-treated group additionally displayed an increase in the expression of osteoblast differentiation genes, including bone morphogenetic protein-2, small mothers against decapentaplegic 1/5/8, runt-related transcription factor 2, osteocalcin, and type I collagen. Vitamin C reduced the expression of osteoclast differentiation genes, such as receptor activator of nuclear factor kappa-B, receptor activator of nuclear factor kappa-B ligand, tartrate-resistant acid phosphatase, and cathepsin K. This study is the first to show that vitamin C can inhibit osteoporosis by promoting osteoblast formation and blocking osteoclastogenesis through the activation of wingless-type MMTV integration site family/β-catenin/activating transcription factor 4 signaling, which is achieved through the serine/threonine kinase and mitogen-activated protein kinase signaling pathways. Therefore, our results suggest that vitamin C improves bone regeneration.

Sesamin Protects the Femoral Head From Osteonecrosis by Inhibiting ROS-Induced Osteoblast Apoptosis in Rat Model

Glucocorticoids intake has become the most common pathogenic factor for osteonecrosis of the femoral head (ONFH). Annually, tens of millions of patients suffer from pain related to ONFH. Researchers have proposed several underlying mechanisms of ONFH, including osteocyte apoptosis, cell differentiation disorder, and angiogenesis hindrance. Sesamin, isolated from Sesamum indicum seeds, was reported could affect osteocyte inflammation and differentiation in osteoarthritis and osteoporosis. We investigated the underlying influence of sesamin on ONFH rat model. Fifteen male Sprague-Dawley rats were randomly divided into three groups. The ONFH model group only received the methylprednisolone (MPS) and lipopolysaccharide (LPS) injection to promote the development of ONFH. The sesamin treatment group was injected with sesamin, MPS, and LPS. The control group was untreated. Rats from above groups were sacrificed 4 weeks later. The effect of sesamin on ONFH rats was validated by H&E staining. TUNEL staining showed that femoral head necrosis was attenuated by sesamin. Furthermore, the phosphorylation of Akt was increased and the downstream cellular apoptosis signal pathway was inhibited. Intracellular ROS level was decreased after sesamin treatment. In conclusion, our findings suggest that sesamin protects the femoral head from osteonecrosis by inhibiting ROS-induced osteoblast apoptosis.

Analysis of anti-osteoporosis function of chlorogenic acid by gene microarray profiling in ovariectomy rat model

The aim of the present study was to clarify the effect of chlorogenic acid (CGA) on estrogen deficiency-induced osteoporosis based on micro-computed tomography (micro-CT) and potential mechanism of gene regulation via microarray profiling. Eighteen female Sprague–Dawley rats were divided randomly into sham-operated group, ovariectomy (OVX) plus saline vehicle group, and OVX plus CGA treatment group (CGA at 45 mg/kg/day). The loss of bone mass of the femoral metaphysis was evaluated by micro-CT to represent. Gene expression profiling was analyzed for bone marrow mesenchymal stem cells (BMSCs) of OVX and OVXT groups. Bioinformatics analysis was used to find the potential pathways regulated by CGA. OVX-induced osteoporosis could decrease femur bone mineral density (BMD), bone volume/tissue volume (BV/TV), trabecula number (Tb.N), and trabecular thickness (Tb.Th) and increased the trabecular separation (Tb.Sp) and structure model index (SMI) in the rats. Gene microarray profiling showed 121 differentially expressed genes in collected BMSCs between OVX and OVXT groups were identified with a threshold of a two-fold change and P<0.05. Kyoto Encyclopedia of Genes and Genomes (KEGG) was used to analyze the potential mechanism of CGA and we observed that many mitogen-activated protein kinase (MAPK) pathway associtated genes were altered, suggesting this pathway may play an important role. CGA improved bone quality by modifying the BMD and trabecular microarchitecture. Differential expression genes were screened by gene microarray profile and the results suggested MAPK pathway might participate in the process of OVX-induced bone remodeling.

A flavonoids compound inhibits osteoclast differentiation by attenuating RANKL induced NFATc-1/c-Fos induction

Function studies of pectolinarigenin demonstrated that, as a natural product, it possesses the regulatory effects on transcription factors (TFs) such as: signal transducer and activator of transcription 3 (STAT3). Herein, we aimed to identify the regulatroy effects of pectolinarigenin on the osteoclastogenesis TFs such as: NFATc1 and c-Fos, and further identify the relevant up-stream signals activity. We initially found pectolinarigenin inhibited receptor activator of nuclear factor-kappa B ligand (RANKL) induced osteoclast formation during the bone marrow-derived macrophages (BMMs) cultures, suggesting that this natural product could act on osteoclast precursors by inhibiting the down signaling cascades of RANKL signaling. Moreover, mechanistical investigation showed pectolinarigenin inhibits RANKL-mediated osteoclastogenesis by attenuating the nuclear factor of activated T cells cytoplasmic 1 (NFATc-1) and c-Fos following the Akt and mitogen activated protein kinases (MAPKs) signaling costimulatory. These findings identify that pectolinarigenin may act as an anti-resorption agent by blocking osteoclast activation.

Identification of Nutritional Components in Black Sesame Determined by Widely Targeted Metabolomics and Traditional Chinese Medicines

Chemical composition of secondary metabolites is of great importance for quality control of agricultural products. Black sesame seeds are significantly more expensive than white sesame seeds, because it is thought that black sesame seeds are more beneficial to human health than white sesame seeds. However, the differences in nutrient composition between black sesame seeds and white sesame seeds are still unknown. The current study examined the levels of different metabolites in black and white sesame seeds via the use of a novel metabolomics strategy. Using widely targeted metabolomics data, we obtained the structure and content of 557 metabolites, out of which 217 metabolites were identified, and discovered 30 metabolic pathways activated by the secondary metabolites in both black and white sesame seeds. Our results demonstrated that the main pathways that were differentially activated included: phenylpropanoid biosynthesis, tyrosine metabolism, and riboflavin metabolism. More importantly, the biomarkers that were significantly different between black seeds and white sesame seeds are highly related to the functions recorded in traditional Chinese medicine. The results of this study may serve as a new theoretical reference for breeding experts to promote the genetic improvement of sesame seeds, and therefore the cultivation of higher quality sesame varieties.

The Role of Semipurified Fractions Isolated from Quercus infectoria on Bone Metabolism by Using hFOB 1.19 Human Fetal Osteoblast Cell Model

Background. Quercus infectoria (QI) is a plant used in traditional medicines in Asia. The plant was reported to contain various active phytochemical compounds that have potential to stimulate bone formation. However, the precise mechanism of the stimulation effect of QI on osteoblast has not been elucidated. The present study was carried out to isolate QI semipurified fractions from aqueous QI extract and to delineate the molecular mechanism of QI semipurified fraction that enhanced bone formation by using hFOB1.19 human fetal osteoblast cell model. Methods. Isolation of QI semipurified fractions was established by means of column chromatography and thin layer chromatography. Established QI semipurified fractions were identified using Liquid Chromatography-Mass Spectrometry (LC-MS). Cells were treated with derived QI semipurified fractions and investigated for mineralization deposition and protein expression level of BMP-2, Runx2, and OPN by ELISA followed gene expression analysis of BMP-2 and Runx2 by RT-PCR. Results. Column chromatography isolation and purification yield Fractions A, B, and C. LC-MS analysis reveals the presence of polyphenols in each fraction. Results show that QI semipurified fractions increased the activity and upregulated the gene expression of BMP-2 and Runx2 at day 1, day 3, and day 7. OPN activity increased in cells treated with QI semipurified fractions at day 1 and day 3. Meanwhile, at day 7, expression of OPN decreased in activity. Furthermore, the study showed that combination of Fractions A, B, and C with osteoporotic drug (pamidronate) further increased the activity and upregulated the gene expression of BMP-2 and Runx2. Conclusions. These findings demonstrated that polyphenols from semipurified fractions of QI enhanced bone formation through expression of the investigated bone-related marker that is its potential role when combined with readily available osteoporotic drug.

Calcium Supplement Derived from Gallus gallus domesticus Promotes BMP-2/RUNX2/SMAD5 and Suppresses TRAP/RANK Expression through MAPK Signaling Activation

The present study evaluated the effects of a calcium (Ca) supplement derived from Gallus gallus domesticus (GD) on breaking force, microarchitecture, osteogenic differentiation and osteoclast differentiation factor expression in vivo in Ca-deficient ovariectomized (OVX) rats. One percent of Ca supplement significantly improved Ca content and bone strength of the tibia. In micro-computed tomography analysis, 1% Ca supplement attenuated OVX- and low Ca-associated changes in bone mineral density, trabecular thickness, spacing and number. Moreover, 1% Ca-supplemented diet increased the expression of osteoblast differentiation marker genes, such as bone morphogenetic protein-2, Wnt3a, small mothers against decapentaplegic 1/5/8, runt-related transcription factor 2, osteocalcin and collagenase-1, while it decreased the expression of osteoclast differentiation genes, such as thrombospondin-related anonymous protein, cathepsin K and receptor activator of nuclear factor kappa B. Furthermore, 1% Ca-supplemented diet increased the levels of phosphorylated extracellular signal-regulated kinase and c-Jun N-terminal kinase. The increased expression of osteoblast differentiation marker genes and activation of mitogen-activated protein kinase signaling were associated with significant increases in trabecular bone volume, which plays an important role in the overall skeletal strength. Our results demonstrated that 1% Ca supplement inhibited osteoclastogenesis, stimulated osteoblastogenesis and restored bone loss in OVX rats.

Estrogenic activity of osthole and imperatorin in MCF-7 cells and their osteoblastic effects in Saos-2 cells

There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy (HRT). The present study was designed to investigate the in vitro effects of estrogen-like activities of two widespread coumarins, osthole and imperatorin, using the MCF-7 cell proliferation assay and their alkaline phosphatase (ALP) activities in osteoblasts Saos-2 cells. The two compounds were found to strongly stimulate the proliferation of MCF-7 cells. The estrogen receptor-regulated ERα, progesterone receptor (PR) and PS2 mRNA levels were increased by treatment with osthole and imperatorin. All these effects were significantly inhibited by the specific estrogen receptor antagonist ICI182, 780. Cell cycle analysis revealed that their proliferation stimulatory effect was associated with a marked increase in the number of MCF-7 cells in S phase, which was similar to that observed with estradiol. It was also observed that they significantly increased ALP activity, which was reversed by ICI182,780. These results suggested that osthole and imperatorin could stimulate osteoblastic activity by displaying estrogenic properties or through the ER pathway. In conclusion, osthole and imperatorin may represent new pharmacological tools for the treatment of osteoporosis.

Liraglutide attenuates the osteoblastic differentiation of MC3T3‑E1 cells by modulating AMPK/mTOR signaling

Liraglutide, a synthetic analogue of glucagon-like peptide-1, is utilized in the treatment of type 2 diabetes and obesity. Liraglutide has been previously demonstrated to prevent osteoblastic differentiation of human vascular smooth muscle cells, resulting in the slowing of arterial calcification, however, its effect on bone formation remains unclear. The present study investigated the effect of liraglutide on osteoblastic differentiation using Alizarin Red S staining, and examined the molecular mechanisms underlying the regulatory effect by western blot analysis. The present study demonstrated that protein expression levels of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) were downregulated in MC3T3-E1 cells during osteoblastic differentiation in commercial osteogenic differentiation medium, whereas protein expression levels of transforming growth factor-β (TGF-β) and phosphorylated mammalian target of rapamycin (p-mTOR) increased. Liraglutide was subsequently demonstrated to dose-dependently attenuate the osteoblastic differentiation of MC3T3-E1 cells, to upregulate p-AMPK, and downregulate p-mTOR and TGF-β protein expression levels. Treatment with an AMPK-specific inhibitor, Compound C, eradicated the effect of liraglutide on osteoblastic differentiation, and p-mTOR and TGF-β downregulation. An mTOR activator, MHY1485, also abolished the inhibitory effect of liraglutide on osteoblastic differentiation, and resulted in p-mTOR and TGF-β downregulation, but did not attenuate the liraglutide-induced increase in p-AMPK protein expression levels. The results of the present study demonstrate that liraglutide attenuates osteoblastic differentiation of MC3T3-E1 cells via modulation of AMPK/mTOR signaling. The present study revealed a novel function of liraglutide, which contributes to the understanding of its pharmacological and physiological effects in clinical settings.

Stimulatory effects of the degradation products from Mg-Ca-Sr alloy on the osteogenesis through regulating ERK signaling pathway

The influence of Mg-1Ca-xwt.% Sr (x = 0.2, 0.5, 1.0, 2.0) alloys on the osteogenic differentiation and mineralization of pre-osteoblast MC3T3-E1 were studied through typical differentiation markers, such as intracellular alkaline phosphatase (ALP) activity, extracellular collagen secretion and calcium nodule formation. It was shown that Mg-1Ca alloys with different content of Sr promoted cell viability and enhanced the differentiation and mineralization levels of osteoblasts, and Mg-1Ca-2.0Sr alloy had the most remarkable and significant effect among all. To further investigate the underlying mechanisms, RT-PCR and Western Blotting assays were taken to analyze the mRNA expression level of osteogenesis-related genes and intracellular signaling pathways involved in osteogenesis, respectively. RT-PCR results showed that Mg-1Ca-2.0Sr alloy significantly up-regulated the expressions of the transcription factors of Runt-related transcription factor 2 (RUNX2) and Osterix (OSX), Integrin subunits, as well as alkaline phosphatase (ALP), Bone sialoprotein (BSP), Collagen I (COL I), Osteocalcin (OCN) and Osteopontin (OPN). Western Blotting results suggested that Mg-1Ca-2.0Sr alloy rapidly induced extracellular signal-regulated kinase (ERK) activation but showed no obvious effects on c-Jun N terminal kinase (JNK) and p38 kinase of MAPK. Taken together, our results demonstrated that Mg-1Ca-2.0Sr alloy had excellent biocompatibility and osteogenesis via the ERK pathway and is expected to be promising as orthopedic implants and bone repair materials.

Effects of electromagnetic fields on osteoporosis: A systematic literature review

Electromagnetic fields (EMFs) as a safe, effective and noninvasive treatment have been researched and used for many years in orthopedics, and the common use clinically is to promote fracture healing. The effects of EMFs on osteoporosis have not been well concerned. The balance between osteoblast and osteoclast activity as well as the balance between osteogenic differentiation and adipogenic differentiation of bone marrow mesenchymal stem cells plays an important role in the process of osteoporosis. A number of recent reports suggest that EMFs have a positive impact on the balances. In this review, we discuss the recent advances of EMFs in the treatment of osteoporosis from basic research to clinical study and introduce the possible mechanism. In addition, we presented future perspectives of application of EMFs for osteoporosis.

p38 MAPK Signaling in Osteoblast Differentiation

The skeleton is a highly dynamic tissue whose structure relies on the balance between bone deposition and resorption. This equilibrium, which depends on osteoblast and osteoclast functions, is controlled by multiple factors that can be modulated post-translationally. Some of the modulators are Mitogen-activated kinases (MAPKs), whose role has been studied in vivo and in vitro. p38-MAPK modifies the transactivation ability of some key transcription factors in chondrocytes, osteoblasts and osteoclasts, which affects their differentiation and function. Several commercially available inhibitors have helped to determine p38 action on these processes. Although it is frequently mentioned in the literature, this chemical approach is not always as accurate as it should be. Conditional knockouts are a useful genetic tool that could unravel the role of p38 in shaping the skeleton. In this review, we will summarize the state of the art on p38 activity during osteoblast differentiation and function, and emphasize the triggers of this MAPK.

Enterococcus faecalis attenuates osteogenesis through activation of p38 and ERK1/2 pathways in MC3T3-E1 cells

AIM

To explore the role of Enterococcus faecalis in the proliferation, apoptosis and differentiation of osteoblasts.

METHODOLOGY

Pre-osteoblastic MC3T3-E1 cells were treated with heat-killed E. faecalis ATCC 29212 and clinical E. faecalis P25RC strains, respectively. Cell proliferation, mineralized calcium deposition, alkaline phosphatase (ALP) activity and apoptosis were assessed at various time-points. The expression levels of osteogenic-related genes including ALP, osteocalcin (OC), runt-related protein 2 (Runx2) and collagen type 1 (COL1) were also analysed throughout the duration of the experiment. Additionally, the involvement of mitogen-activated protein kinases (MAPKs) signalling pathways was analysed by Western blotting. In the presence of culture supernatant from E. faecalis-treated murine macrophages, apoptosis of MC3T3-E1 cells was detected with flow cytometry. Data were analysed using analysis of variance (anova), and P < 0.05 was considered significantly different.

RESULTS

E. faecalis significantly inhibited proliferation (P < 0.05) and also significantly induced apoptosis of MC3T3-E1 cells (P < 0.05), whilst differentiation seemed to be unaffected after 7 days of E. faecalis treatment. However, osteogenic differentiation was significantly inhibited with 21-day E. faecalis treatment (P < 0.05). The p38 and ERK1/2 phosphorylation pathways associated with mineral deposition and apoptosis were significantly activated in MC3T3-E1 cells. The culture supernatants from E. faecalis-treated macrophages induced osteoblast apoptosis.

CONCLUSIONS

E. faecalis exerted an inhibitory effect on osteogenesis in pre-osteoblastic MC3T3-E1 cells via phosphorylation of p38 and ERK1/2.

Sesamol decreases melanin biosynthesis in melanocyte cells and zebrafish: Possible involvement of MITF via the intracellular cAMP and p38/JNK signalling pathways

The development of antimelanogenic agents is important for the prevention of serious aesthetic problems such as melasma, freckles, age spots and chloasma. The aim of this study was to investigate the antimelanogenic effect of sesamol, an active lignan isolated from Sesamum indicum, in melan-a cells. Sesamol strongly inhibited melanin biosynthesis and the activity of intracellular tyrosinase by decreasing cyclic adenosine monophosphate (cAMP) accumulation. Sesamol significantly decreased the expression of melanogenesis-related genes, such as tyrosinase, tyrosinase-related protein-1,2 (TRP-1,2), microphthalmia-associated transcription factor (MITF) and melanocortin 1 receptor (MC1R). In addition, sesamol also induces phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK). Moreover, sesamol dose-dependently decreased zebrafish pigment formation, tyrosinase activity and expression of melanogenesis-related genes. These findings indicate that sesamol inhibited melanin biosynthesis by down-regulating tyrosinase activity and melanin production via regulation of gene expression of melanogenesis-related proteins through modulation of MITF activity, which promoted phosphorylation of p38 and JNK in melan-a cells. Together, these results suggest that sesamol strongly inhibits melanin biosynthesis, and therefore, sesamol represents a new skin-whitening agent for use in cosmetics.

An 8-O-4' norlignan exerts oestrogen-like actions in osteoblastic cells via rapid nongenomic ER signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Sambucus williamsii Hance (SWH), which belongs to the Caprifoliaceae family distributed in various regions of China, Korea and Japan, has been used as a folk medicine for treatment of bone and joint diseases in China for thousands of years. In previous studies, SWH was shown to possess anti-osteoporosis, healing fracture, anti-inflammatory and analgesic activities. Our previous studies showed that SWH extract effectively suppressed ovariectomy-induced increase in bone turnover and improved bone mineral density and bone biomechanical strength in rats as well as in mice. An 8-O-4' norlignan, (7R,8S)-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol (PPD) was previously isolated and identified as the bioactive ingredient in SWH. The present study aimed to characterize the bone protective effects as well as its mechanism of actions in osteoblasts.

MATERIALS AND METHODS

Bone protective actions of PPD on different cells were determined by proliferation assay, alkaline phosphatase (ALP) activity assay, calcium deposition as well as real-time reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, estrogen receptor (ER) antagonist ICI182,780 and mitogen-activated protein kinase kinase (MEK) inhibitor U0126 blocking assays, competitive ER radioligand binding assay, ERE-dependent luciferase reporter assay and immunoblotting were used to determine if PPD activated ER and if the effects of PPD on osteoblastic functions were ER dependent.

RESULTS

PPD exerted anabolic effects in osteoblasts and its effects were abolished by co-incubation with ICI182,780 or U0126. PPD induced mRNA expressions of Runx2, ALP, osteocalcin, and increased the ratio of osteoprotegerin/receptor activator of nuclear factor κB (OPG/RANKL). PPD failed to bind to either ERα or ERβ and did not activate ERE-luciferase activity via ER. PPD induced the phosphorylation of extracellular regulated kinases (ERK) and its effect was completely abolished by U0126. It also induced the phosphorylation of ERα at serine 118.

CONCLUSION

These data show that PPD is a bioactive compound in SWH that exerts oestrogen-like actions in osteoblast-like cells via ligand-independent, estrogen response element (ERE)-independent and mitogen-activated protein (MAP) Kinase-mediated rapid nongenomic ER signaling pathway.

The Effect of Quercetin on the Osteogenesic Differentiation and Angiogenic Factor Expression of Bone Marrow-Derived Mesenchymal Stem Cells

Bone marrow-derived mesenchymal stem cells (BMSCs) are widely used in regenerative medicine in light of their ability to differentiate along the chondrogenic and osteogenic lineages. As a type of traditional Chinese medicine, quercetin has been preliminarily reported to promote osteogenic differentiation in osteoblasts. In the present study, the effects of quercetin on the proliferation, viability, cellular morphology, osteogenic differentiation and angiogenic factor secretion of rat BMSCs (rBMSCs) were examined by MTT assay, fluorescence activated cell sorter (FACS) analysis, real-time quantitative PCR (RT-PCR) analysis, alkaline phosphatase (ALP) activity and calcium deposition assays, and Enzyme-linked immunosorbent assay (ELISA). Moreover, whether mitogen-activated protein kinase (MAPK) signaling pathways were involved in these processes was also explored. The results showed that quercetin significantly enhanced the cell proliferation, osteogenic differentiation and angiogenic factor secretion of rBMSCs in a dose-dependent manner, with a concentration of 2 μM achieving the greatest stimulatory effect. Moreover, the activation of the extracellular signal-regulated protein kinases (ERK) and p38 pathways was observed in quercetin-treated rBMSCs. Furthermore, these induction effects could be repressed by either the ERK inhibitor PD98059 or the p38 inhibitor SB202190, respectively. These data indicated that quercetin could promote the proliferation, osteogenic differentiation and angiogenic factor secretion of rBMSCs in vitro, partially through the ERK and p38 signaling pathways.

Human myeloma cell lines induce osteoblast downregulation of CD99 which is involved in osteoblast formation and activity

CD99 is a transmembrane glycoprotein expressed in physiological conditions by cells of different tissues, including osteoblasts (OBs). High or low CD99 levels have been detected in various pathological conditions, and the supernatant of some carcinoma cell lines can modulate CD99 expression in OB-like cells. In the present work we demonstrate for the first time that two different human myeloma cell lines (H929 and U266) and, in a less degree, their conditioned media significantly downregulate CD99 expression in normal human OBs during the differentiation process. In the same experimental conditions the OBs display a less differentiated phenotype as demonstrated by the decreased expression of RUNX2 and Collagen I. On the contrary, when CD99 was activated by using a specific agonist antibody, the OBs become more active as demonstrated by the upregulation of Alkaline Phosphatase, Collagen I, RUNX2, and JUND expression. Furthermore, we demonstrate that the activation of CD99 is able to induce the phosphorylation of ERK 1/2 and AKT intracellular signal transduction molecules in the OBs.

Whole body vibration improves osseointegration by up-regulating osteoblastic activity but down-regulating osteoblast-mediated osteoclastogenesis via ERK1/2 pathway

Due to the reduction in bone mass and deterioration in bone microarchitecture, osteoporosis is an important risk factor for impairing implant osseointegration. Recently, low-magnitude, high-frequency (LMHF) vibration (LM: <1×g; HF: 20-90Hz) has been shown to exhibit anabolic, but anti-resorptive effects on skeletal homeostasis. Therefore, we hypothesized that LMHF loading, in terms of whole body vibration (WBV), may improve implant fixation under osteoporotic status. In the in vivo study, WBV treatment (magnitude: 0.3g, frequency: 40Hz, time: 30min/12h, 5days/week) was applied after hydroxyapatite-coated titanium implants were inserted in the bilateral tibiae of ovariectomized rats. The bone mass and the osteospecific gene expressions were measured at 12weeks post implantation. In the in vitro study, the cellular and molecular mechanisms underlying osteoblastic and osteoclastic activities were fully investigated using various experimental assays. Micro-CT examination showed that WBV could enhance osseointegration by improving microstructure parameters surrounding implants. WBV-regulated gene levels in favor of bone formation over resorption may be the reason for the favorable adaptive bone remolding on bone-implant surface. The in vitro study showed that vibration (magnitude: 0.3g, frequency: 40Hz, time: 30min/12h) up-regulated osteoblast differentiation, matrix synthesis and mineralization. However, mechanically regulated osteoclastic activity was mainly through the effect on osteoblastic cells producing osteoclastogenesis-associated key soluble factors, including RANKL and M-CSF. Osteoblasts were therefore the direct target cells during the mechanotransduction process. The ERK1/2 pathway was demonstrated to play an essential role in vibration-induced enhancement of bone formation and decreased bone resorption. Our data suggests that WBV was a helpful non-pharmacological intervention for improving osseointegration under osteoporosis.

Quercus infectoria Gall Extract Enhanced the Proliferation and Activity of Human Fetal Osteoblast Cell Line (hFOB 1.19)

BACKGROUND

The present study investigated the effects of Quercus infectoria (QI) gall extract on the proliferation, alkaline phosphatase (ALP), osteocalcin, and the morphology of a human fetal osteoblast cell line (hFOB 1.19).

METHODS

The cells were cultured in Dulbecco's modified eagle medium F12 supplemented with a 10% fetal bovine serum, a 1% penicillin/streptomycin and were treated with QI at various concentrations (0.1 to 99.0 μg/mL) for 72 hours. The levels of ALP and osteocalcin were measured at day 1, 3, 7, 10, and 14 and were compared among the negative control, pamidronate and QI groups.

RESULTS

The median effective concentration (EC50) of hFOB 1.19 treated with QI was 10.30 μg/mL. This concentration was more effective compared to the control drug, pamidronate (EC50 at 16.09 μg/mL). The ALP and osteocalcin levels of hFOB 1.19 treated with QI from day 7 and onwards were significantly increased in a time and concentration-dependent manner. Interestingly, from day 7 until day 14, the ALP and osteocalcin levels were highest in the cells treated with QI compared to the other two groups. The morphology of cells treated with QI was uniformly elongated, higher in number and over-confluent.

CONCLUSION

After treatment with QI, cell proliferation enhanced and ALP and osteocalcin levels increased.

A comprehensive review on the role of various materials in the osteogenic differentiation of mesenchymal stem cells with a special focus on the association of heat shock proteins and nanoparticles

Mesenchymal stem cells (MSCs) have important roles in the area of regenerative medicine and clinical applications due to their pluripotent nature. Osteogenic differentiation of MSCs has been studied extensively using various stimulants to develop models of bone repair. There are several factors that enhance the differentiation of MSCs into bone tissues. This review focuses on the effects of various inducers on the osteoblast differentiation of MSCs at different stages of cellular development. We discuss the various growth factors, hormones, vitamins, cytokines, chemical stimulants, and mechanical forces applied in bioreactors that play an essential role in the proliferation, differentiation, and matrix mineralization of stem cells during osteogenesis. Various nanoparticles have also been used recently for the same purpose and the results are promising. Moreover, we review the role of various stresses, including thermal stress, and the subsequent involvement of heat shock proteins as inducers of the proliferation and differentiation of osteoblasts. We also report how various proteasome inhibitors have been shown to induce proliferation and osteogenic differentiation of MSCs in a number of cases. In this communication, the role of peptide-based scaffolds in osteoblast proliferation and differentiation is also reviewed. Based on the reviewed information, this article proposes novel possibilities for the enhancement of proliferation, differentiation, and migration of osteoblasts from MSCs. © 2014 S. Karger AG, Basel.

Differentiation therapy: sesamin as an effective agent in targeting cancer stem-like side population cells of human gallbladder carcinoma

BACKGROUND

Recent studies have demonstrated that side population (SP) cells isolated from various cancer cell lines and primary tumors possess stem cell-like properties. Sesamin, a food-derived agent, possesses anti-cancer activities both in vitro and in vivo. The present study was designed to determine whether sesamin also have effects on cancer stem-like SP cells from gallbladder cancer (GBC).

METHODS

In this study, we sorted SP cells by flow cytometry. SP cells were cultured and treated with sesamin. Tumor-sphere formation, colony formation, Matrigel invasion and tumorigenic potential were determined. Expression of nuclear NF-κB, IL-6, p-Stat3, Twist, E-cadherin and Vimentin was measured by Western blot, immunofluorescence staining or RT-PCR analysis. Nuclear NF-κB activity and IL-6 protein level were assessed with ELISA. Xenograft tumors were generated in nude mice.

RESULTS

After treated with sesamin, SP cells differentiated into cells expressing the epithelial marker (E-cadherin). Sesamin effectively affected SP cells stem cell-like characteristics (i.e., tumor-sphere formation, colony-formation, Matrigel invasion), weakened the drug-resistance of SP cells and inhibited tumor growth both in vitro and in vivo. Treatment with sesamin significantly reduced the expression of nuclear NF-κB, IL-6, p-Stat3, Twist and Vimentin (a mesenchymal marker) in SP cells. Nuclear NF-κB activity and IL-6 level were also decreased after treatment with sesamin.

CONCLUSION

Food-derived sesamin directs the epithelial differentiation of cancer stem-like SP cells from GBC, which is associated with attenuation of NF-κB-IL-6-Stat3-Twist signal pathway.

Effects of 6-Hydroxyflavone on Osteoblast Differentiation in MC3T3-E1 Cells

Osteoblast differentiation plays an essential role in bone integrity. Isoflavones and some flavonoids are reported to have osteogenic activity and potentially possess the ability to treat osteoporosis. However, limited information concerning the osteogenic characteristics of hydroxyflavones is available. This study investigates the effects of various hydroxyflavones on osteoblast differentiation in MC3T3-E1 cells. The results showed that 6-hydroxyflavone (6-OH-F) and 7-hydroxyflavone (7-OH-F) stimulated ALP activity. However, baicalein and luteolin inhibited ALP activity and flavone showed no effect. Up to 50 μM of each compound was used for cytotoxic effects study; flavone, 6-OH-F, and 7-OH-F had no cytotoxicity on MC3T3-E1 cells. Moreover, 6-OH-F activated AKT and serine/threonine kinases (also known as protein kinase B or PKB), extracellular signal-regulated kinases (ERK 1/2), and the c-Jun N-terminal kinase (JNK) signaling pathways. On the other hand, 7-OH-F promoted osteoblast differentiation mainly by activating ERK 1/ 2 signaling pathways. Finally, after 5 weeks of 6-OH-F induction, MC3T3-E1 cells showed a significant increase in the calcein staining intensity relative to merely visible mineralization observed in cells cultured in the osteogenic medium only. These results suggested that 6-OH-F could activate AKT, ERK 1/2, and JNK signaling pathways to effectively promote osteoblastic differentiation.

Angiopoietin-1 peptide QHREDGS promotes osteoblast differentiation, bone matrix deposition and mineralization on biomedical materials

Bone loss occurs as a consequence of a variety of diseases as well as from traumatic injuries, and often requires therapeutic intervention. Strategies for repairing and replacing damaged and/or lost bone tissue include the use of biomaterials and medical implant devices with and without osteoinductive coatings. The soluble growth factor angiopoietin-1 (Ang-1) has been found to promote cell adhesion and survival in a range of cell types including cardiac myocytes, endothelial cells and fibroblasts through an integrin-dependent mechanism. Furthermore, the short sequence QHREDGS has been identified as the integrin-binding sequence of Ang-1 and as a synthetic peptide has been found to possess similar integrin-dependent effects as Ang-1 in the aforementioned cell types. Integrins have been implicated in osteoblast differentiation and bone mineralization, processes critical to bone regeneration. By binding integrins on the osteoblast surface, QHREDGS could promote cell survival and adhesion, as well as conceivably osteoblast differentiation and bone mineralization. Here we immobilized QHREDGS onto polyacrylate (PA)-coated titanium (Ti) plates and polyethylene glycol (PEG) hydrogels. The osteoblast differentiation marker, alkaline phosphatase, peaked in activity 4-12 days earlier on the QHREDGS-immobilized PA-coated Ti plates than on the unimmobilized, DGQESHR (scrambled)- and RGDS-immobilized surfaces. Significantly more bone matrix was deposited on the QHREDGS-immobilized Ti surface than on the other surfaces as determined by atomic force microscopy. The QHREDGS-immobilized hydrogels also had a significantly higher mineral-to-matrix (M/M) ratio determined by Fourier transform infrared spectroscopy. Alizarin Red S and von Kossa staining and quantification, and environmental scanning electron microscopy showed that while both the QHREDGS- and RGDS-immobilized surfaces had extensive mineralization relative to the unimmobilized and DGQESHR-immobilized surfaces, the mineralization was more considerable on the QHREDGS-immobilized surface, both with and without the induction of osteoblast differentiation. Finally, treatment of cell monolayers with soluble QHREDGS was demonstrated to upregulate osteogenic gene expression. Taken together, these results demonstrate that the QHREDGS peptide is osteoinductive, inducing osteoblast differentiation, bone matrix deposition and mineralization.

Involvement of MAPK signaling pathway in the osteogenic gene expressions of Cervi Pantotrichum Cornu in MG-63 human osteoblast-like cells

AIMS

The purposes of this study were to determine whether Cervi Pantotrichum Cornu (CPC) has osteogenic activities in human osteoblastic MG-63 cells and to investigate the underlying molecular mechanism.

MAIN METHODS

The effects of CPC on alkaline phosphatase activity, collagen synthesis, and calcium deposits were measured. The COL1A1, ALPL, BGLAP, and SPP1 expressions were measured by real-time PCR. Phosphorylated MAP kinases (ERK1/2, JNK1/2, p38, ELK1, and cJUN) were studied by western blot analysis. The involvement of MAPK pathway in osteogenic gene expressions was determined by using each selective MAPK inhibitor (PD98059, SP600125, and SB203580).

KEY FINDINGS

CPC increased alkaline phosphatase activity, collagen synthesis, and calcium deposits. CPC activated ERK1/2, JNK1/2, p38, and ELK1 phosphorylation except cJUN. CPC increased the COL1A1, ALPL, BGLAP, and SPP1 gene expressions. The elevated COL1A1 and BGLAP expressions were inhibited by PD98059, SP600125 or SB203580. The elevated ALPL expression was blocked by SB203580. The elevated SPP1 expression was inhibited by SP600125 or SB203580. CPC increased COL1A1 and BGLAP expressions via ERK1/2, JNK1/2, and p38 MAPKs pathways and SPP1 expression via JNK1/2 and p38 pathways. p38 pathway is needed for ALPL expression.

SIGNIFICANCE

These results imply that MAPK signaling pathway is an indispensable factor for bone matrix genes expression of CPC in MG-63 human osteoblast-like cells.

The roles of bone morphogenetic proteins and their signaling in the osteogenesis of adipose-derived stem cells

Large-size bone defects can severely compromise both aesthetics and musculoskeletal functions. Adipose-derived stem cells (ASCs)-based bone tissue engineering has recently become a promising treatment strategy for the above situation. As robust osteoinductive cytokines, bone morphogenetic proteins (BMPs) are commonly used to promote the osteogenesis of ASCs. In this process, BMP signaling plays a pivotal role. However, it remains ambiguous how the pleiotrophic BMPs are involved in the commitment of ASCs along osteogenesis instead of other lineages, such as adipogenesis. BMP receptor type-IB, extracellular signal-regulated kinase, and Wnt5a appear to be the main switches controlling the in vitro osteogenic commitment of ASCs. Tumor necrosis factor-alpha, an acute inflammatory cytokine, is reported to play an important role in mediating osteogenic commitment of ASCs in vivo. In addition, various active agents and methods have been used to enhance and accelerate the osteogenesis of ASCs through promoting BMP signaling. In this review, we summarize the current knowledge on the roles of BMPs and their signaling in the osteogenesis of ASCs in vitro and in vivo.