Effects of astragaloside IV on glucocorticoid-induced avascular necrosis of the femoral head via regulating Akt-related pathways.

We investigated the role of astragaloside IV (AS-IV) in preventing glucocorticoid-induced avascular necrosis of the femoral head (ANFH) and the underlying molecular mechanisms. Network pharmacology was used to predict the molecular targets of AS-IV. Molecular dynamic simulations were performed to explore the binding mechanism and interaction mode between AS-IV and Akt. Rat models of glucocorticoid-induced ANFH with AS-IV intervention were established, and osteogenesis, angiogenesis, apoptosis and oxidative stress were evaluated before and after blocking the PI3K/Akt pathway with LY294002. The effects of glucocorticoid and AS-IV on bone marrow mesenchymal stem cells and human umbilical vein endothelial cells incubated with and without LY294002 were determined. Downregulated p-Akt expression could be detected in the femoral heads of glucocorticoid-induced ANFH patients and rats. AS-IV increased trabecular bone integrity and vessel density of the femoral head in the model rats. AS-IV increased Akt phosphorylation and upregulated osteogenesis-, angiogenesis-, apoptosis- and oxidative stress-related proteins and mRNA and downregulated Bax, cleaved caspase-3 and cytochrome c levels. AS-IV promoted human umbilical vein endothelial cell migration, proliferation and tube formation ability; bone marrow mesenchymal stem cell proliferation; and osteogenic differentiation under glucocorticoid influence. AS-IV inhibited apoptosis. LY294002 inhibited these effects. AS-IV prevented glucocorticoid-induced ANFH by promoting osteogenesis and angiogenesis via the Akt/Runx2 and Akt/HIF-1α/VEGF pathways, respectively, and suppressing apoptosis and oxidative stress via the Akt/Bad/Bcl-2 and Akt/Nrf2/HO-1 pathways, respectively.

Merlin functions as a critical regulator in Staphylococcus aureus-induced osteomyelitis.

Merlin is known as a tumor suppressor, while its role in osteomyelitis remains unclear. This study aimed to investigate the role of Merlin in Staphylococcus aureus-induced osteomyelitis and its underlying mechanisms. S. aureus-induced osteomyelitis mouse model was established in Merlinfl/fl Lyz2cre/+ and Merlinfl/fl Lyz2+/+ mice. Bone marrow-derived macrophages (BMDMs) were isolated and stimulated by lipopolysaccharide (LPS). Bioassays, including quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blot analysis, and enzyme-linked immunosorbent assays, were conducted to determine the levels of target genes or proteins. Immunoprecipitation was applied to determine the interactions between proteins. DCAF1fl/fl mice were further crossed with Lyz2-Cre mice to establish myeloid cell conditional knockout mice (DCAF1fl/fl Lyz2cre/+ ). It was found that the level of Merlin was elevated in patients with osteomyelitis and S. aureus-infected BMDMs. Merlin deficiency in macrophages suppressed the production of inflammatory cytokines and ameliorated the symptoms of osteomyelitis induced by S. aureus. Merlin deficiency in macrophages also suppressed the production of proinflammatory cytokines in BMDMs induced by LPS. The inhibitory effects of Merlin deficiency on the inflammatory response were associated with DDB1-Cul4-associated factor 1 (DCAF1). In summary, Merlin deficiency ameliorates S. aureus-induced osteomyelitis through the regulation of DCAF1.

Astragaloside IV ameliorates steroid-induced osteonecrosis of the femoral head by repolarizing the phenotype of pro-inflammatory macrophages.

Osteonecrosis of the femoral head (ON-FH) is a common complication of steroid use. Pro-inflammatory macrophages play a crucial role in the apoptosis of osteocytes. The objective of the study was to evaluate a plant extract astragaloside IV (AS-IV) in treating ON-FN. Bone-marrow-derived macrophages (BMDMs) were treated with lipopolysaccharides (LPS), IFN-γ or IL-4 to induce M1 and M2-like phenotypes. Quantitative real-time PCR and Western blot were used to examine M1 and M2 phenotypic markers. Flow cytometry was used to analyze MHC II, CD206, F4/80, and CD11b levels and cell apoptosis. Glucocorticoid was used to induce ON-FN in mice. TNF-α and IL-1ß levels in femoral head were determined using enzyme-linked immunosorbent assay. AS-IV repolarized macrophages from M1 to M2 phenotypes. Culture medium from AS-IV treated M1 macrophages induced less cell apoptosis osteocytes compared to that from untreated M1 macrophages. In ON-FH mice, the ratio of M1 macrophages was decreased in the femoral head by AS-IV, concomitant with a decrease in TNF-α and IL-1ß levels. AS-IV is effective in alleviating ON-FH through its effects in repolarizing macrophages from M1-like phenotype to M2-like phenotype, promoting survival of osteocytes, reducing arthritic symptoms, and decreasing inflammatory cytokines.

Tumor necrosis factor-α promotes Staphylococcus aureus-induced osteomyelitis through downregulating endothelial nitric oxide synthase.

BACKGROUND: Infections of Staphylococcus aureus (S. aureus) often result in osteomyelitis, which is the acute or chronic infections of the bone marrow or bones. TNF-α is long recognized as a key factor contributing to the pathogenesis of osteomyelitis, but little is known about the underlying molecular mechanism. METHODS: Expression levels of TNF-α, and several candidate genes, including endothelial nitric oxide synthase (eNOS), known to be downregulated by TNF-α were analysed in MC3T3-E1 cells with S. aureus infection and osteomyelitis patient blood. MicroRNA(miR)-129-5p was predicted and experimentally verified to target eNOS. Alizarin red sulfate (ARS) and alkaline phosphatase (ALP) staining assays were conducted on MC3T3-E1 cells with S. aureus infection to assess the role of TNF-α/miR-129-5p/eNOS on mineralization defect. RESULTS: TNF-α and miR-129-5p were upregulated while eNOS was downregulated in MC3T3-E1 cells with S. aureus infection and osteomyelitis patients, showing inversely correlated expression profiles. MiR-129-5p directly binds to the 3'-UTR of eNOS mRNA to suppress eNOS expression in MC3T3-E1 cells. TNF-α blocker inhibited miR-129-5p and elevated eNOS expression, likely contributing to rescued mineralization defect in S. aureus-infected MC3T3-E1 cells. During S. aureus infection, upregulated TNF-α increases endogenous miR-129-5p expression, which in turn inhibits eNOS, contributing to osteomyelitis. CONCLUSION: Our study thereby proposes a novel signalling cascade involving TNF-α/miR-129-5p/eNOS in the pathogenesis of osteomyelitis, which may also serve as therapeutic targets.

Involvement of mechanosensitive ion channels in the effects of mechanical stretch induces osteogenic differentiation in mouse bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (BMSCs) can be induced to process osteogenic differentiation with appropriate mechanical and/or chemical stimuli. The present study described the successful culture of murine BMSCs under mechanical strain. BMSCs were subjected to 0%, 3%, 8%, 13%, and 18% cyclic tensile strain at 0.5 Hz for 8 hr/day for 3 days. The expression of osteogenic markers and mechanosensitive ion channels was evaluated with real-time reverse transcription-polymerase chain reaction (RT-PCR) and western blot. The expression of alkaline phosphatase (ALP) and matrix mineralization were evaluated with histochemical staining. To investigate the effects of mechanosensitive ion channel expression on cyclic tensile strain-induced osteogenic differentiation, the expression of osteogenic markers was evaluated with real-time RT-PCR in the cells without mechanosensitive ion channel expression. This study revealed a significant augment in osteogenic marker in BMSC strained at 8% compared to other treatments; therefore, an 8% strain was used for further investigations. The ALP expression and matrix mineralization were enhanced in osteogenic induced BMSCs subjected to 8% strain after 7 and 14 days, respectively. Under the same conditions, the osteogenic marker and mechanosensitive ion channel expression were significantly promoted. However, the loss function of mechanosensitive ion channels resulted in the inhibition of osteogenic marker expression. This study demonstrated that strain alone can successfully induce osteogenic differentiation in BMSCs and the expression of mechanosensitive ion channels was involved in the process. The current findings suggest that mechanical stretch could function as efficient stimuli to induce the osteogenic differentiation of BMSCs via the activation of mechanosensitive ion channels.

Network pharmacology based virtual screening of active constituents of Prunella vulgaris L. and the molecular mechanism against breast cancer.

Prunella vulgaris L, a perennial herb widely used in Asia in the treatment of various diseases including cancer. In vitro studies have demonstrated the therapeutic effect of Prunella vulgaris L. against breast cancer through multiple pathways. However, the nature of the biological mechanisms remains unclear. In this study, a Network pharmacology based approach was used to explore active constituents and potential molecular mechanisms of Prunella vulgaris L. for the treatment of breast cancer. The methods adopted included active constituents prescreening, target prediction, GO and KEGG pathway enrichment analysis. Molecular docking experiments were used to further validate network pharmacology results. The predicted results showed that there were 19 active ingredients in Prunella vulgaris L. and 31 potential gene targets including AKT1, EGFR, MYC, and VEGFA. Further, analysis of the potential biological mechanisms of Prunella vulgaris L. against breast cancer was performed by investigating the relationship between the active constituents, target genes and pathways. Network analysis showed that Prunella vulgaris L. exerted a promising preventive effect on breast cancer by acting on tumor-associated signaling pathways. This provides a basis to understand the mechanism of the anti-breast cancer activity of Prunella vulgaris L.

The promotion of bone regeneration through CS/GP-CTH/antagomir-133a/b sustained release system.

Few studies reported the application of miRNA in bone regeneration. In this study, the expression of miR133a and miR133b in murine BMSCs was inhibited via antagomiR-133a/b and the osteogenic differentiation in murine BMSCs was evaluated. The RT-PCR, flow cytometry, cell counting kit-8, and annexin V-FITC/PI double staining assays were performed. Double knockdown miR133a and miR133b can promote BMSC osteogenic differentiation. At optimum N/P ration (15:1), the loading efficiency can reach over 90%. CTH-antagomiR-133a/b showed no cytotoxicity to BMSCs and diminished miR133a and miR133b expression in BMSCs. Furthermore, chitosan-based sustained delivery system can facilitate continuous dosing of antagomiR-133a/b, which enhanced calcium deposition and osteogenic specific gene expression in vitro. The new bone formation was enhanced after the sustained delivery system containing CTH-antagomiR-133a/b nanoparticles was used in mouse calvarial bone defect model. Our results demonstrate that CTH nanoparticles could facilitate continuous dosing of antagomiR133a/b, which can promote osteogenic differentiation.

Inhibition of microRNA-222 up-regulates TIMP3 to promotes osteogenic differentiation of MSCs from fracture rats with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is the most common diabetes and has numerous complications. Recent studies demonstrated that T2DM compromises bone fracture healing in which miR-222 might be involved. Furthermore, tissue inhibitor of metalloproteinase 3 (TIMP-3) that is the target of miR-222 accelerates fracture healing. Therefore, we assume that miR-222 could inhibit TIMP-3 expression. Eight-week-old rats were operated femoral fracture or sham, following the injection of streptozotocin (STZ) to induce diabetes one week later in fractured rats, and then, new generated tissues were collected for measuring the expression of miR-222 and TIMP-3. Rat mesenchymal stem cells (MSCs) were isolated and treated with miR-222 mimic or inhibitor to analyse osteogenic differentiation. MiR-222 was increased in fractured rats and further induced in diabetic rats. In contrast, TIMP-3 was reduced in fractured and further down-regulated in diabetic rats. Luciferase report assay indicated miR-222 directly binds and mediated TIMP-3. Furthermore, osteogenic differentiation was suppressed by miR-222 mimic and promoted by miR-222 inhibitor. miR-222 is a key regulator that is promoted in STZ-induced diabetic rats, and it binds to TIMP3 to reduce TIMP-3 expression and suppressed MSCs' differentiation.

ATP6V1H facilitates osteogenic differentiation in MC3T3-E1 cells via Akt/GSK3ß signaling pathway.

Type 2 diabetes mellitus (T2DM) accounts for approximately 90% of all diabetic patients, and osteoporosis is one of the complications during T2DM process. ATP6V1H (V-type proton ATPase subunit H) displays crucial roles in inhibiting bone loss, but its role in osteogenic differentiation remains unknown. Therefore in this study, we aimed to explore the biological role of ATP6V1H in osteogenic differentiation. OM (osteogenic medium) and HG (high glucose and free fatty acids) were used to induce the MC3T3-E1 cells into osteogenic differentiation in a T2DM simulating environment. CCK8 assay was used to detect cell viability. Alizarin Red staining was used to detect the influence of ATP6V1H on osteogenic differentiation. ATP6V1H expression increased in OM-MC3T3-E1 cells, while decreased in OM+HG-MC3T3-E1 cells. ATP6V1H promoted osteogenic differentiation of OM+HG-MC3T3-E1 cells. Overexpression of ATP6V1H inhibited Akt/GSK3ß signaling pathway, while knockdown of ATP6V1H promoted Akt/GSK3ß signaling pathway. ATP6V1H overexpression promoted osteogenic differentiation of OM+HG-MC3T3-E1 cells. The role of ATP6V1H in osteogenic differentiation in a T2DM simulating environment involved in Akt/GSK3ß signaling pathway. These data demonstrated that ATP6V1H could serve as a potential target for osteogenic differentiation in a T2DM simulating environment.

A high-fat diet aggravates osteonecrosis through a macrophage-derived IL-6 pathway.

Inflammation plays an important role in osteonecrosis. Obesity, a risk factor for osteonecrosis, leads to a chronic inflammatory status. We hypothesized that inflammation mediated the effects of obesity on osteonecrosis and tested our hypothesis in a mouse model of osteonecrosis. We fed mice with a high-fat diet (HFD) for 12 weeks before osteonecrosis induction by methylprednisolone and examined bone structure and IL-6 expression. Then we investigated the effects of IL-6 deletion in mice with osteonecrosis on the HFD. Next, we isolated bone marrow cells and determined the cell types responsible for HFD-induced IL-6 secretion. Finally, we investigated the roles of macrophages and macrophage-driven IL-6 in HFD-mediated effects on osteonecrosis and osteogenesis of bone marrow stromal cells (BMSCs). The HFD lead to exacerbated destruction of the femoral head in mice with osteonecrosis and increased IL-6 expression in macrophages. Il-6 knockout or macrophage depletion suppressed the effects of the HFD on bone damage. When co-cultured with macrophages isolated from HFD-fed mice with osteonecrosis, BMSCs showed reduced viability and suppressed osteogenic differentiation. Our results suggest that macrophage-driven IL-6 bridges obesity and osteonecrosis and inhibition of IL-6 or depletion of macrophage may represent a therapeutic strategy for obesity-associated osteonecrosis.

Coatings as the useful drug delivery system for the prevention of implant-related infections.

Implant-related infections (IRIs) which led to a large amount of medical expenditure were caused by bacteria and fungi that involve the implants in the operation or in ward. Traditional treatments of IRIs were comprised of repeated radical debridement, replacement of internal fixators, and intravenous antibiotics. It needed a long time and numbers of surgeries to cure, which meant a catastrophe to patients. So how to prevent it was more important than to cure it. As an excellent local release system, coating is a good idea by its local drug infusion and barrier effect on resisting biofilms which were the main cause of IRIs. So in this review, materials used for coatings and evidences of prevention were elaborated.

Lithium-containing biomaterials inhibit osteoclastogenesis of macrophages in vitro and osteolysis in vivo.

Osteolysis, which is caused by aging, neoplasia, infection, or trauma, is a type of intractable systemic or local syndrome of bone destruction (e.g., peri-implant osteolysis (PIO)). The activation of osteoclasts differentiated from macrophages plays a decisive role in such diseases. To conquer this challenge, herein, a biomaterial capable of inhibiting osteoclastogenesis and osteolysis was designed. Recent research has shown that lithium (Li) can inhibit pro-inflammatory cytokine release in vitro via affecting the pharmacotherapy of psychiatric illnesses. Therefore, we synthesized a pure-phase lithium-calcium-silicate (Li2Ca2Si2O7, LCS) bioceramic and further prepared extracts to assess the effect of LCS on RANKL-induced osteoclastogenesis in vitro and Ti particle-induced osteolysis in vivo as well as the corresponding mechanism. The results demonstrated that LCS inhibited RANKL-induced osteoclastogenesis of macrophages, bone resorption area, and F-actin ring formation in a dose-dependent manner. The mechanism is related to the suppression of the NF-kB signaling pathways mediating the inhibitory effects of LCS. Moreover, LCS was found to be able to inhibit calvarial osteolysis in a mouse model through micro-CT and histological analysis. These findings suggest that LCS may be a promising biomaterial for suppressing osteolysis, thus paving the way for the treatment of osteoporosis using bioactive inorganic materials.

Release of vancomycin and tobramycin from polymethylmethacrylate cements impregnated with calcium polyphosphate hydrogel.

The influence of calcium polyphosphate (CPP) gel incorporation on the release of vancomycin and tobramycin from polymethyl methacrylate (PMMA) cement (Simplex P, SP) has been studied. Adding 10% CPP gel to SP led to a much lower burst release of vancomycin and considerably extended release of both vancomycin and tobramycin up to 24 weeks. Antibiotics released from this new material retain their bactericidal activity for up to 15 weeks. The improvement in the antibiotic release is mainly due to the molecular interactions of antibiotics with embedded CPP polyphosphate chains as confirmed by Raman spectroscopy analysis. The inclusion of CPP hydrogel also increased the SP surface roughness and pore sizes, leading to a higher release rate of antibiotics. The new material is biocompatible and has similar handling properties and mechanical strength as compared to SP cements. We believe that incorporating CPP gel provides a better and usable drug carrier for PMMA cement. © 2017 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2827-2840, 2018.

Muscone exerts protective roles on alcohol-induced osteonecrosis of the femoral head.

Long-term alcohol abuse causes musculoskeletal disorders, among of which, alcohol-induced osteonecrosis of the femoral head (ONFH) is of concern due to its significant and severe complications. A variety of methods have been attempted to prevent alcohol-induced ONFH, and monomers extracted from Chinese herbs might benefit the disease profoundly. In the current study, muscone, the main ingredient of musk, was used to prevent alcohol-induced ONFH. In vitro, ethanol was used to affect the potential of osteogenesis and proliferation of human bone mesenchymal stem cells (hBMSCs), and beneficial role of muscone was investigated on hBMSCs. In vivo, following the establishment of alcohol-induced ONFH, muscone was employed to treat the diseased rats, which were analyzed by micro-CT scanning and a series of histologic staining. As a result, we found ethanol could significantly suppress osteogenic differentiation of hBMSCs, while muscone held the potential to promote ALP activity and mRNA expressions of COL1 and OCN under ethanol treatment. Meanwhile, imaging analysis revealed muscone could restore BV/TV ratio and bone mineral density of the necrotic femoral head, and the protective role of muscone on alcohol-induced ONFH was further confirmed by histologic examinations. Our study confirmed the protective effect of muscone against alcohol-induced ONFH both in vitro and in vivo. Therefore, muscone may be considered as a valuable therapeutic natural drug for alcohol-induced ONFH in humans.

Combination of Erythromycin and Curcumin Alleviates Staphylococcus aureus Induced Osteomyelitis in Rats.

Osteomyelitis is commonly caused by Staphylococcus aureus. Both erythromycin and curcumin can suppress S. aureus growth, but their roles in osteomyelitis are barely studied. We aim to explore the activities of erythromycin and curcumin against chronical osteomyelitis induced by methicillin-resistant S. aureus (MRSA). Chronicle implant-induced osteomyelitis was established by MRSA infection in male Wistar rats. Four weeks after bacterial inoculation, rats received no treatment, erythromycin monotherapy, curcumin monotherapy, or erythromycin plus curcumin twice daily for 2 weeks. Bacterial levels, bone infection status, inflammatory signals and side effects were evaluated. Rats tolerated all treatments well, with no death or side effects such as, diarrhea and weight loss. Two days after treatment completion, erythromycin monotherapy did not suppress bacterial growth and had no effect in bone infection, although it reduced serum pro-inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6. Curcumin monotherapy slightly suppressed bacterial growth, alleviated bone infection and reduced TNF-α and IL-6. Erythromycin and curcumin combined treatment markedly suppressed bacterial growth, substantially alleviated bone infection and reduced TNF-α and IL-6. Combination of erythromycin and curcumin lead a much stronger efficiency against MRSA induced osteomyelitis in rats than monotherapy. Our study suggests that erythromycin and curcumin could be a new combination for treating MRSA induced osteomyelitis.

Solanum Muricatum Promotes Osteogenic Differentiation of Rat Bone Marrow Stromal Cells.

Solanum muricatum (SM), also known as pepino, is known for its antioxidative and anti-inflammatory effects. The aim of this study was to evaluate the effects of SM extract in promoting osteogenic differentiation and regulating the Wnt and bone morphogenetic protein (BMP) signaling pathways. Ingredients of pepino were extracted and identified. SM extracts were used to treat rat bone marrow stromal cells (BMSCs), followed by evaluating alkaline phosphatase activities and mineralization levels. The mRNA levels of osteogenic biomarkers, including OPN and Collagen I, were also evaluated with real-time polymerase chain reaction. After treatment with SM extracts, the expressions of key proteins in the Wnt and BMP signaling pathways were assessed. DKK-1 and noggin, which are Wnt and BMP inhibitors, respectively, were added with SM extracts to investigate the role of Wnt and BMP pathways in the ameliorating effects of SM extract in osteogenesis. Treatment of BMSCs with SM extract promoted osteogenesis. Meanwhile, upregulations in the Wnt and BMP pathways were also observed. However, inhibiting both pathways compromised the effects of SM extract in promoting osteogenic differentiation. SM extract promotes osteogenic differentiation in BMSCs via promoting the Wnt and BMP signaling pathways.

ß-Carotene suppresses osteoclastogenesis and bone resorption by suppressing NF-κB signaling pathway.

AIMS: ß-Carotene is a natural anti-oxidant, which has been used for treatment of cancer and cardiovascular diseases. Recently, the ameliorating function of ß-carotene in osteoporosis has been implicated. However, the precise mechanism of ß-carotene in prevention and treatment of osteoporosis is largely unknown. In the present study, we aimed to elucidate how ß-carotene affects osteoclast formation and bone resorption. MAIN METHODS: Bone marrow-derived monocytes/-macrophages (BMM) were exposed to 0.05, 0.1, 0.2, 0.4 and 0.6µM ß-carotene, followed by evaluation of cell viability, lactate dehydrogenase (LDH) release, receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis and resorption pits formation. Key factors in nuclear factor kappa B (NF-ĸB) and mitogen-activated protein kinases (MAPK) pathways were evaluated with western blot after BMM cells were exposed to RANKL and ß-carotene. The effects of ß-carotene in nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), c-Fos and cathepsin K (CTSK) expression were also evaluated. KEY FINDINGS: ß-Carotene significantly inhibited BMM viability and promoted LDH release at concentrations of 0.4 and 0.6µM. A decrease in RANKL-induced osteoclastogenesis and resorption was also observed after ß-carotene treatment. ß-Carotene attenuated the NF-ĸB pathway activation by RANKL, with no effect on MAPK pathway. ß-Carotene suppressed the upregulation of NFATc1 and c-Fos by RANKL. SIGNIFICANCE: We clarified the anti-osteoclastogenic role of ß-carotene, which is mediated by NF-κB signaling.

Curcumin protects human adipose-derived mesenchymal stem cells against oxidative stress-induced inhibition of osteogenesis.

The detrimental effects of oxidative stress on the skeletal system have been documented, and understanding the mechanisms is important to design a therapeutic strategy. As an antioxidant and anti-inflammatory agent, the active ingredient of turmeric curcumin has been used as medication for numerous complications including bone loss. However, it is unclear if curcumin could influence the osteogenic potential of mesenchymal stem cells (MSCs), particularly in oxidative injuries. Here we demonstrate that curcumin treatment protects cell death caused by hydrogen peroxide (H2O2) exposure in human adipose-derived MSCs in vitro. Importantly, curcumin is able to enhance the osteoblast differentiation of human adipose-derived MSCs that is inhibited by H2O2. Notably, both oxidative stress and the inhibition of Wnt/ß-catenin signaling are attenuated by curcumin treatment. These results suggest that curcumin can promote osteoblast differentiation of MSCs and protect the inhibitory effect elicited by oxidative injury. The findings support potential use of curcumin or related antioxidants in MSC-based bone regeneration for disease related with oxidative stress-induced bone loss.

New strategy to rescue the inhibition of osteogenesis of human bone marrow-derived mesenchymal stem cells under oxidative stress: combination of vitamin C and graphene foams.

To rescue the oxidative stress induced inhibition of osteogenesis, vitamin C (VC) was chemically modified onto three-dimensional graphene foams (3D GFs), then their regulation on osteogenesis of human bone marrow-derived mesenchymal stem cells (BM-MSCs) was studied. Combined action of VC + GF significantly decreased H2O2-induced oxidative stress, and rescued H2O2-inhibited cell viability, differentiation and osteogenesis of BM-MSCs in vitro. Further studies revealed that Wnt pathway may be involved in this protection of osteogenesis. Furthermore, an in vivo mouse model of BM-MSCs transplantation showed that VC + GF remarkably rescued oxidative stress inhibited calcium content and bone formation. The combination of VC and GF exhibited more pronounced protective effects against oxidative stress induced inhibition of osteogenesis, compared to monotherapy of VC or GF. Our study proposed a new strategy in stem cell-based therapies for treating bone diseases.

TNF-α-induced NF-κB activation upregulates microRNA-150-3p and inhibits osteogenesis of mesenchymal stem cells by targeting ß-catenin.

Although systemic or local inflammation, commonly featured by cytokine activation, is implicated in patients with bone loss, the underlying mechanisms are still elusive. As microRNAs (miR), a class of small non-coding RNAs involved in essential physiological processes, have been found in bone cells, we aimed to investigate the role of miR for modulating osteogenesis in inflammatory milieu using human bone marrow mesenchymal stem cells (hBM-MSCs). Induced by proinflammatory cytokine TNF-α, miR-150-3p was identified as a key player in suppressing osteogenic differentiation through downregulating ß-catenin, a transcriptional co-activator promoting bone formation. TNF-α treatment increased the levels of miR-150-3p, which directly targeted the 3'-UTR of ß-catenin mRNA and in turn repressed its expression. In addition, we observed that miR-150-3p expression was increased by TNF-α via IKK-dependent NF-κB signalling. There are three putative NF-κB binding sites in the promoter region of miR-150, and we identified -686 region as the major NF-κB binding site for stimulation of miR-150 expression by TNF-α. Finally, the osteogenic differentiation of hBM-MSCs was inhibited by either miR-150-3p overexpression or TNF-α treatment, which was prevented by anti-miR-150-3p oligonucleotides. Taken together, our data suggested that miR-150-3p integrated inflammation signalling and osteogenic differentiation and may contribute to the inhibition effects of inflammation on bone formation, thus expanding the pathophysiological functions of microRNAs in bone diseases.