Calycosin-7-O-β-d-glucopyranoside stimulates osteoblast differentiation through regulating the BMP/WNT signaling pathways

Qi-Gu capsule alleviates osteoporosis by inhibiting mesenchymal stem cell senescence via the HIF-1α/AMPK axis

BACKGROUND

Osteoporosis (OP) represents a systemic disease causing reduced bone mass and fragility fractures. Qigu Capsule (QGC), a traditional Chinese medicine, shows potential in alleviating human OP, but its precise mechanisms remain unclear, limiting clinical application.

METHODS

The bioactive components of QGC were analyzed using high-performance liquid chromatography (HPLC). An ovariectomy (OVX)-provoked OP rat model was established to evaluate QGC's effects on bone mass, trabecular architecture, and mechanical strength using micro-CT, histological staining, and biomechanical testing. RNA-seq analysis of human OP-derived mesenchymal stem cell (MSC) samples was performed to identify oxidative stress (OxS)- and senescence-associated gene changes. OxS-induced MSC senescence was modeled in vitro using H₂O₂, and QGC's effects on MSC proliferation, migration, and osteogenic differentiation were assessed. Network pharmacology (NP) was deployed to predict the key mechanisms behind the QGC treatment of OP. Further mechanistic studies utilized pharmacological inhibitors and siRNA-mediated gene knockdown to confirm the involvement of critical signaling pathways.

RESULTS

HPLC-MS analysis identified 505 unique bioactive compounds in QGC. In vivo, QGC significantly improved BMD, enhanced trabecular microarchitecture, and restored mechanical properties in OVX rats. ELISA, histological, and immunohistochemical analyses confirmed that QGC primarily enhanced osteoblast activity. RNA-seq analysis of GEO datasets revealed upregulation of senescence and OxS markers (P53, CDKN1A, and INOS) in human OP-derived MSCs. Both in vivo and in vitro QGC alleviated OxS-induced MSC senescence, reduced reactive oxygen species (ROS) levels, suppressed senescence and OxS marker, and promoted MSC proliferation, migration, and osteogenic differentiation. Moreover, NP predicted HIF-1α signaling as critical in QGC's regulation of MSC function during OP. Mechanistic studies demonstrated that QGC activated the HIF-1α/AMPK axis, and inhibition of either HIF-1α or AMPK abolished its therapeutic effects.

CONCLUSION

QGC mitigates OxS-induced MSC senescence and promotes osteogenesis through the HIF-1α/AMPK axis, highlighting its mechanistic basis in treating OP. These findings show QGC's potential as a therapeutic agent, not only by promoting osteogenesis but also by complementing or serving as an alternative to current OP treatments, offering valuable prospects for enhanced clinical management.

Sanqi oral solution alleviates podocyte apoptosis in experimental membranous nephropathy by mediating EMT through the ERK/CK2-α/β-catenin pathway

Introduction

Sanqi oral solution (SQ) is a Chinese medicine that has been used well to treat idiopathic membranous nephropathy (IMN). It has been demonstrated to mitigate IMN proteinuria by inhibiting podocyte apoptosis. however, the precise mechanism has not been fully elucidated.

Methods

A passive Heymann nephropathy (PHN) rat model was used to mimic the in vivo disease characteristics of IMN. The PHN rats were intragastrically administered SQ (12.6/6.3 mL/kg) or tacrolimus (0.315 mg/kg) for 21 days. SQ was applied to ADR-induced podocytes in vitro. The effects of SQ on IMN and its underlying mechanisms were determined by measuring biochemical indices, pathomorphological characteristics, membrane attack complex (MAC), cell morphology, and protein levels.

Results

The SQ ingredients found in rat serum underscored their successful absorption in rats. In PHN rats, SQ induced a significant reduction in proteinuria, MAC, C5b-9, and glomerular basement membrane thickness, along with a drop in apoptotic podocytes. Similarly, SQ exerted a protective effect against ADR-induced podocyte injury by inhibiting apoptosis. Furthermore, inhibition of the ERK/CK2-α/β-catenin pathway-mediated epithelial-to-mesenchymal transition (EMT) was found to be involved in the anti-apoptotic effect of SQ in PHN rats and podocytes, marked by the reduction in vimentin and α-SMA and the induction of Synaptopodin and Podocin protein levels.

Conclusion

Inhibition of EMT via the ERK/CK2-α/β-catenin pathway may be the main mechanism by which SQ suppresses podocyte apoptosis in IMN.

New-QiangGuYin-Containing Serum Inhibits Osteoclast-Derived Exosome Secretion and Down-Regulates Notum to Promote Osteoblast Differentiation

New-QiangGuYin (N-QGY), the addition of sea buckthorn on the basis of QGY formula, is herbal formula widely used clinically in China for the treatment of osteoporosis (OP), but its mechanism warrants further exploration. The mechanisms of QGY and N-QGY in the treatment of OP are probed from the perspective of osteoclast-osteoblast balance. Thirty Sprague-Dawley rats are randomly divided into N-QGY group, QGY group, and Control group. Beyond control rats that orally took normal saline, other rats are orally administered with isometric N-QGY or QGY twice every day for 3 days. The drug-containing serum and control serum are prepared and their effects on osteoclast-derived exosome secretion are determined by bicinchoninic acid assay (BCA), nanoparticle tracking analysis, and Western blot. GW4869 and Interleukin-1β (IL-1β) are adopted as the exosome inhibitor and inducer, respectively. Exosome uptake, cell counting kit-8, alkaline phosphatase (ALP) staining, alizarin red staining, enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, and Western blot are performed to examine the effects of altered osteoclast exosome content on osteogenic differentiation of mesenchymal stem cells (MSCs). N-QGY, QGY, and GW4869 inhibit osteoclast-derived exosome secretion and exosome uptake by MSCs, whereas IL-1β exerted the opposite effects (p < 0.05). Different from IL-1β, N-QGY, QGY, and GW4869 partially elevated MSC viability, osteocalcin secretion, ALP, RUNX Family Transcription Factor 2 (RUNX2) and Osteopontin (OPN) expressions, and calcium deposition in the osteoclast-MSCs coculture system (p < 0.05). Mechanically, osteoclasts increased Notum protein level but decreased β-catenin level, which is enhanced by IL-1β but is reversed by GW4869, QGY, and N-QGY (p < 0.05). And the effect of N-QGY is more conspicuous than that of QGY (P<0.05). N-QGY-containing serum inhibits exosome levels in osteoclasts, thereby enhancing osteogenic differentiation of MSCs via inhibition of Notum protein and promotion of β-catenin protein.

Craniotubular Dysplasia Ikegawa Type: Further Delineation of the Phenotype

Craniotubular Dysplasia Ikegawa type is a sclerosing bone disorder recently identified in five patients from four independent Indian families. It is caused by homozygous or compound heterozygous mutations in TMEM53. Deficient TMEM53 leads to overactive BMP signaling which promotes bone formation. Here, we present another three siblings with intronic mutations in TMEM53, identified by exome sequencing, from a Caucasian family. All three siblings displayed skeletal and radiographic features, similar to the earlier described individuals. All our patients had additional features such as cardiac and urogenital anomalies. Our results confirm the phenotype of CTDI. We discuss whether the additional features in our patients are separate from CTDI or reflect a broader spectrum of the syndrome.

Unraveling the mechanism in l-Caldesmon regulating the osteogenic differentiation of PDLSCs: An innovative perspective

Maxillofacial bone defect is one of the common symptoms in maxillofacial, which affects the function and aesthetics of maxillofacial region. Periodontal ligament stem cells (PDLSCs) are extensively used in bone tissue engineering. The mechanism that regulates the osteogenic differentiation of PDLSCs remains not fully elucidated. Previous studies demonstrated that l-Caldesmon (l-CALD, or CALD1) might be involved in the osteogenic differentiation of PDLSCs. Here, the mechanism by which CALD1 regulates the osteogenic differentiation of PDLSCs is investigated. The osteogenic differentiation of PDLSCs is enhanced with Cald1 knockdown. Whole transcriptome sequencing (RNA-seq) analysis shows that bone morphogenetic proteins (BMP) signaling pathway and Wingless type (Wnt) pathway have significant change with Cald1 knockdown, and the expressions of Wnt-induced secreted protein 1 (WISP1), BMP2, Smad1/5/9, and p-Smad1/5/9 are significantly upregulated, while Glycogen synthase kinase 3β (GSK3β) and p-GSK3β are downregulated. In addition, subcutaneous implantation in nude mice shows that knockdown of Cald1 enhances the osteogenic differentiation of PDLSCs in vivo. Taken together, this study demonstrates that knockdown of Cald1 enhances the osteogenic differentiation of PDLSCs by BMP and Wnt signaling pathways, and provides a novel approach for subsequent clinical treatment.

Isoflavones isolated from chickpea sprouts alleviate ovariectomy-induced osteoporosis in rats by dual regulation of bone remodeling

Osteoporosis is a common systemic skeletal disease and a predominant underlying factor in the increased occurrence of fractures. The structure of isoflavones resembles that of estrogen and can confer similar but weaker effects. This study investigated the potential inhibitory effects of isoflavones from chickpea sprouts (ICS) on ovariectomy (OVX)-induced osteoporosis in vitro and in vivo. Notably, we found that ICS treatment could attenuate bone loss and improve trabecular microarchitecture and biomechanical properties of the fourth lumbar vertebra in OVX-induced osteoporotic rats and could also inhibit the development of a hyperosteometabolic state in this model. The osteogenic differentiation of bone marrow stem cells (BMSCs) was significantly enhanced by ICS intervention in vitro, and we confirmed that estrogen receptor α signaling was required for this increased osteogenic differentiation. Additionally, ICS has been shown to inhibit bone resorption via ERa modulation of the OPG/RANKL pathway. RANKL-induced osteoclastogenesis was reduced under ICS treatment, supporting that NF-κB signaling was inhibited by ICS. Thus, ICS attenuates osteoporosis progression by promoting osteogenic differentiation and inhibiting osteoclastic resorption. These results support the further exploration and development of ICS as a pharmacological agent for the treatment and prevention of osteoporosis.

Efficacy and Possible Mechanisms of Astragali Radix and its Ingredients in Animal Models of Osteoporosis: A Preclinical Review and Metaanalysis

BACKGROUND

Astragali Radix (AR) has a long history as a traditional Chinese medicine for anti-osteoporosis (OP) treatment. The aim of the study was to explore the effect and optimal regimens of AR and its main ingredients (IAR) in OP treatment.

METHODS

Eligible animal studies were searched in seven databases (PubMed, Web of Science, MEDLINE, SciELO Citation Index, Cochrane Library, China National Knowledge Infrastructure and Wanfang). The primary outcomes were bone metabolic indices. The secondary outcome measure was the anti-OP mechanism of IAR.

RESULTS

21 studies were enrolled in the study. The primary findings of the present article illustrated that IAR could significantly increase the bone mineral density (BMD), bone volume over the total volume, trabecular number, trabecular thickness, bone maximum load and serum calcium, while trabecular separation and serum C-terminal telopeptide of type 1 collagen were remarkably decreased (P < 0.05). In subgroup analysis, the BMD in the long treatment group (≥ 10 weeks) showed better effect size than the short treatment group (< 10 weeks) (P < 0.05). Modeling methods and animal sex were factors affecting serum alkaline phosphatase and osteocalcin levels.

CONCLUSION

The findings suggest the possibility of developing IAR as a drug for the treatment of OP. IAR with longer treatment time may achieve better effects regardless of animal strain and age.

Synthetic Calcium-Phosphate Materials for Bone Grafting

Synthetic bone grafting materials play a significant role in various medical applications involving bone regeneration and repair. Their ability to mimic the properties of natural bone and promote the healing process has contributed to their growing relevance. While calcium-phosphates and their composites with various polymers and biopolymers are widely used in clinical and experimental research, the diverse range of available polymer-based materials poses challenges in selecting the most suitable grafts for successful bone repair. This review aims to address the fundamental issues of bone biology and regeneration while providing a clear perspective on the principles guiding the development of synthetic materials. In this study, we delve into the basic principles underlying the creation of synthetic bone composites and explore the mechanisms of formation for biologically important complexes and structures associated with the various constituent parts of these materials. Additionally, we offer comprehensive information on the application of biologically active substances to enhance the properties and bioactivity of synthetic bone grafting materials. By presenting these insights, our review enables a deeper understanding of the regeneration processes facilitated by the application of synthetic bone composites.

Selenomethionine against titanium particle-induced osteolysis by regulating the ROS-dependent NLRP3 inflammasome activation via the β-catenin signaling pathway

Wear debris-induced osteolysis, especially titanium (Ti) particles-induced osteolysis, is the most common cause of arthroplasty failure with no effective therapy. Previous studies have suggested that inflammation and impaired osteogenesis are associated with Ti particles -induced osteolysis. Selenium (Se) is an essential trace element in the human body, which forms selenomethionine (Se-Met) in nature, and selenoproteins has strong anti-inflammatory and antioxidant stress effects. In this study, the effects of Se-Met on Ti particles-induced osteolysis were observed and the potential mechanism was explored. We found that exogenous Se-Met relieved osteolysis induced by Ti particles in two animal models and MC3T3-E1 cells. We found that the addition of Se-Met effectively inhibited Ti particle-induced inflammation by regulating reactive oxygen species-dependent (ROS-dependent) NOD-like receptor protein 3 (NLRP3) inflammasome activation. These therapeutic effects were abrogated in MC3T3-E1 cells that had received a β-catenin antagonist, suggesting that Se-Met alleviates inflammatory osteolysis via the β-catenin signaling pathway. Collectively, these findings indicated that Se-Met may serve as a potential therapeutic agent for treating Ti particle-induced osteolysis.

Nanoplatforms for Promoting Osteogenesis in Ovariectomy-Induced Osteoporosis in the Experimental Model

Background:

Osteoporosis is a debilitating bone ailment characterized by the obvious loss of bone mass and bone microarchitecture impairment.

Objective:

This study aimed to illuminate the in vivo usefulness of nanotechnology as a treatment for osteoporosis via analyzing the effectiveness of nano-hydroxyapatite (nHa), nano-hydroxy- apatite/chitosan (nHa/C), and nano-hydroxyapatite/silver (nHa/S) in mitigation of osteoporosis in ovariectomized rats.

Method:

The characterization of the nHa, nHa/C, and nHa/S was carried out using TEM, SEM, FTIR, and Zeta potential measurements. This in vivo study included 48 adult female rats that were randomized into six groups (8 rats/group): (1) Sham-operated control, (2) osteoporotic, (3) nHa, (4) nHa/C, (5) nHa/S, and (6) Fosamax®. Serum osterix level was quantified using ELISA. Femur bone morphogenetic protein 2 and SMAD1 mRNA levels were evaluated by qPCR. The femur bones were scanned by DEXA for measurement of bone mineral density and bone mineral content. In ad-dition, a histopathological examination of femur bones was performed.

Results:

The present approach denoted that the treatment with nHa, nHa/C, or nHa/S yields a signif-icant rise in serum level of osterix and mRNA levels of bone morphogenetic protein 2 and SMAD1 as well as significant enhancements of bone tissue minerals.

Conclusion:

The findings affirmed the potency of nHa, nHa/C, and nHa/S as auspicious nanoplat-forms for repairing bone defects in the osteoporotic rat model. The positive effect of the inspected nanoformulations arose from bone formation indicators in serum and tissue, and additionally, the reinforcement of bone density and content, which were verified by the histopathological description of bone tissue sections.

Fluoride induces hypomethylation of BMP2 and activates osteoblasts through the Wnt/β-catenin signaling pathway

BACKGROUND

Skeletal fluorosis has become a public health issue in recent years as its serious impact on patients' life expectancy. Bone morphogenetic protein 2 (BMP2) plays a key role in promoting osteogenesis. However, the mechanism of BMP2-Wnt/β-catenin axis in skeletal fluorosis needs further exploration.

METHODS

The RT-qPCR and western blot assay were carried out to examine the mRNA and protein levels. Cell viability was measured by MTT assay. A commercial ALP assay kit was used to detect ALP activities. Alizarin Red staining was performed to measure the formation of mineralized nodules. Methylation-specific PCR (MSP) was performed to measure the methylation level of BMP2.

RESULTS

Fluoride promoted the expression of osteogenic marker genes (OPN, OCN, OSX and RUNX2) and induced the proliferation and differentiation of MC3T3-E1 cells. Fluoride induced hypomethylation and high expression of BMP2. Furthermore, knockdown of BMP2 reversed the promoting effect of fluoride on osteogenic differentiation of MC3T3-E1. The expression of β-catenin, glycogen synthase kinase 3β (GSK3β), wingless/integrated 3α (Wnt3α), low-density lipoprotein receptor-related protein 5 (LRP5) and dishevelled 1 (Dv1) were increased in osteoblasts treated with fluoride, however, knockdown of BMP2 reversed this phenomenon. Simultaneous knockdown of BMP2 and β-catenin significantly inhibited the differentiation of osteoblasts induced by fluoride.

CONCLUSION

Fluoride contributed to proliferation and differentiation of osteoblasts through BMP2-Wnt/β-catenin axis, providing a feasible theoretical basis for the treatment of skeletal fluorosis.

Astragalus polysaccharide alleviates alveolar bone destruction by regulating local osteoclastogenesis during periodontitis

Inflammatory imbalance of bone formation/resorption leads to alveolar bone destruction. Astragalus polysaccharide has been confirmed to have anti-inflammatory effects. We sought to disclose the protective effect and its potential mechanisms of astragalus polysaccharide in the periodontitis model. Experimental periodontitis was induced by cotton ligatures for this study. We measured the alveolar bone damage rate, periodontal osteoclasts, proportion of CD4+Foxp3+, CD4+IL-10+, CD4+TGF-β+ subsets in the gingiva, and RANKL, OPG, TGF-β+, and IL-10+ level in the gingiva. We also cultured osteoclast precursor cells in the presence of RANKL and astragalus polysaccharide. Osteoclasto-like cells were identified by TRAP staining, mRNA of RANK, TRAP, and TRAF6 were evaluated by real time PCR. We found that astragalus polysaccharide caused significant protection of the alveolar bone via reducing local osteoclasts. It also decreased the proportion of CD4+Foxp3+ cells and upregulated the level of CD4+IL-10+ cells, reduced RANKL, and remedied IL-10 levels. In cell culture experiments, astragalus polysaccharide prohibited the RANKL mediated osteoclast differentiation. The findings of this study disclose the functions and possible mechanisms of astragalus polysaccharide engaged in local osteoclastogenesis, and reveal the considerable effect of astragalus polysaccharide in alveolar bone homeostasis and its likely contribution to host immuno-regulation in periodontitis.

Gentiopicroside promotes the osteogenesis of bone mesenchymal stem cells by modulation of β-catenin-BMP2 signalling pathway

Osteoporosis is characterized by increased bone fragility, and the drugs used at present to treat osteoporosis can cause adverse reactions. Gentiopicroside (GEN), a class of natural compounds with numerous biological activities such as anti‐resorptive properties and protective effects against bone loss. Therefore, the aim of this work was to explore the effect of GEN on bone mesenchymal stem cells (BMSCs) osteogenesis for a potential osteoporosis therapy. In vitro, BMSCs were exposed to GEN at different doses for 2 weeks, whereas in vivo, ovariectomized osteoporosis was established in mice and the therapeutic effect of GEN was evaluated for 3 months. Our results in vitro showed that GEN promoted the activity of alkaline phosphatase, increased the calcified nodules in BMSCs and up‐regulated the osteogenic factors (Runx2, OSX, OCN, OPN and BMP2). In vivo, GEN promoted the expression of Runx2, OCN and BMP2, increased the level of osteogenic parameters, and accelerated the osteogenesis of BMSCs by activating the BMP pathway and Wnt/β‐catenin pathway, effect that was inhibited using the BMP inhibitor Noggin and Wnt/β‐catenin inhibitor DKK1. Silencing the β‐catenin gene and BMP2 gene blocked the osteogenic differentiation induced by GEN in BMSCs. This block was also observed when only β‐catenin was silenced, although the knockout of BMP2 did not affect β‐catenin expression induced by GEN. Therefore, GEN promotes BMSC osteogenesis by regulating β‐catenin‐BMP signalling, providing a novel strategy in the treatment of osteoporosis.

Aesculetin Accelerates Osteoblast Differentiation and Matrix-Vesicle-Mediated Mineralization

The imbalance between bone resorption and bone formation in favor of resorption results in bone loss and deterioration of bone architecture. Osteoblast differentiation is a sequential event accompanying biogenesis of matrix vesicles and mineralization of collagen matrix with hydroxyapatite crystals. Considerable efforts have been made in developing naturally-occurring plant compounds, preventing bone pathologies, or enhancing bone regeneration. Coumarin aesculetin inhibits osteoporosis through hampering the ruffled border formation of mature osteoclasts. However, little is known regarding the effects of aesculetin on the impairment of matrix vesicle biogenesis. MC3T3-E1 cells were cultured in differentiation media with 1–10 μM aesculetin for up to 21 days. Aesculetin boosted the bone morphogenetic protein-2 expression, and alkaline phosphatase activation of differentiating MC3T3-E1 cells. The presence of aesculetin strengthened the expression of collagen type 1 and osteoprotegerin and transcription of Runt-related transcription factor 2 in differentiating osteoblasts for 9 days. When ≥1–5 μM aesculetin was added to differentiating cells for 15–18 days, the induction of non-collagenous proteins of bone sialoprotein II, osteopontin, osteocalcin, and osteonectin was markedly enhanced, facilitating the formation of hydroxyapatite crystals and mineralized collagen matrix. The induction of annexin V and PHOSPHO 1 was further augmented in ≥5 μM aesculetin-treated differentiating osteoblasts for 21 days. In addition, the levels of tissue-nonspecific alkaline phosphatase and collagen type 1 were further enhanced within the extracellular space and on matrix vesicles of mature osteoblasts treated with aesculetin, indicating matrix vesicle-mediated bone mineralization. Finally, aesculetin markedly accelerated the production of thrombospondin-1 and tenascin C in mature osteoblasts, leading to their adhesion to preformed collagen matrix. Therefore, aesculetin enhanced osteoblast differentiation, and matrix vesicle biogenesis and mineralization. These findings suggest that aesculetin may be a potential osteo-inductive agent preventing bone pathologies or enhancing bone regeneration.

Calycosin-7-O-β-Glucoside Isolated from Astragalus membranaceus Promotes Osteogenesis and Mineralization in Human Mesenchymal Stem Cells

Stem cells have received attention in various diseases, such as inflammatory, cancer, and bone diseases. Mesenchymal stem cells (MSCs) are multipotent stem cells that are critical for forming and repairing bone tissues. Herein, we isolated calycosin-7-O-β-glucoside (Caly) from the roots of Astragalus membranaceus, which is one of the most famous medicinal herbs, and investigated the osteogenic activities of Caly in MSCs. Caly did not affect cytotoxicity against MSCs, whereas Caly enhanced cell migration during the osteogenesis of MSCs. Caly increased the expression and enzymatic activities of ALP and the formation of mineralized nodules during the osteogenesis of MSCs. The osteogenesis and bone-forming activities of Caly are mediated by bone morphogenetic protein 2 (BMP2), phospho-Smad1/5/8, Wnt3a, phospho-GSK3β, and phospho-AKT, inducing the expression of runt-related transcription factor 2 (RUNX2). In addition, Caly-mediated osteogenesis and RUNX2 expression were attenuated by noggin and wortmannin. Moreover, the effects were validated in pre-osteoblasts committed to the osteoblast lineages from MSCs. Overall, our results provide novel evidence that Caly stimulates osteoblast lineage commitment of MSCs by triggering RUNX2 expression, suggesting Caly as a potential anabolic drug to prevent bone diseases.

Flavonoids in Bone Erosive Diseases: Perspectives in Osteoporosis Treatment

Imbalance of bone homeostasis, with excessive bone resorption compared with bone formation, leads to the development of progressive osteopenia leading to lower bone resistance to load, with consequent pain and functional limitations. Phytochemicals with therapeutic and preventive effects against bone resorption have recently received increasing attention since they are potentially more suitable for long-term use than traditional therapeutic chemical compounds. In this systematic review of the literature of the past 5 years, comprehensive information is provided on flavonoids with potential antiresorption and pro-osteogenic effects. It aims to highlight the molecular mechanisms of these molecules, often epigenetic, and their possible pharmacological use, which is of great importance for the prevention and treatment of osteoporosis (OP).

Protective effect of hyperoside against hydrogen peroxide-induced dysfunction and oxidative stress in osteoblastic MC3T3-E1 cells

Oxidative stress can induce apoptosis and decrease activities of osteoblasts. Hyperoside (HYP) is a potent antioxidant derived from Chinese herb. This study aims to evaluate the protective effects provided by HYP to osteoblastic MC3T3-E1 cells. MC3T3-E1 cells were pre-treated with HYP for 24 h before being treated with 0.3 mM hydrogen peroxide (H₂O₂) for 24 h. Cell viability, flow cytometric analysis and mRNA expression of alkaline phosphatase (ALP), collagen I (COL-I) and osteocalcin (OCN) in MC3T3-E1 cells were examined. We next examined apoptosis-related and mitogen-activated protein kinase (MAPK) related proteins in HYP and H₂O₂ groups. HYP over the dose of 40 μmol/L could obviously increase the MC3T3-E1 cell viability at 24 h and 48 h (p < .05). HYP significantly (p < .05) increased mRNA expression of ALP, COL-I and OCN than H₂O₂ group. Moreover, HYP decreased the apoptosis rate and apoptosis-related proteins that induced by H₂O₂. In addition, HYP decreased the production of phosphorylated Jun N-terminal kinase (JNK) and p38 levels of osteoblastic MC3T3-E1 cells induced by H₂O₂. These results demonstrated that the protective effect provided by HYP to osteoblastic MC3T3-E1 cells was mediated, at least in part, via inhibition of MAPK signalling pathway and oxidative damage of the cells.

Biomimetic mineralization of novel hydroxyethyl cellulose/soy protein isolate scaffolds promote bone regeneration in vitro and in vivo

Although various strategies have been utilized to accelerate bone regeneration in bone tissue engineering (BTE), the treatment and repair of large bone defects remains a clinical challenge worldwide. Inspired by the natural extracellular matrix of bone tissue, organic-inorganic composite scaffolds with three-dimensional (3D) porous structures, sufficient mechanical properties, excellent cytocompatibility, osteoconductivity, and osteogenic potential have received considerable attention within the field of bone engineering. In this work, a novel epichlorohydrin (ECH)-crosslinked hydroxyethyl cellulose (HEC)/soy protein isolate (SPI) porous bi-component scaffold (EHSS) with hydroxyapatite (HAp) functionalization (EHSS/HAp) was constructed for bone defect repair via the combination of lyophilization and in situ biomimetic mineralization. Systematic characterization experiments were performed to assess the morphology, HAp-forming properties, mechanical properties and degradation rate of the scaffold. The results indicated that the prepared scaffolds exhibited an interconnected porous structure, a biomimetic HAp coating on their surfaces, improved mechanical properties in compression and a controllable degradation rate. In particular, semiquantitative analysis showed that the calcium/phosphorus (Ca/P) ratio of EHSS/HAp with 70% SPI content (1.65) was similar to that of natural bone tissue (1.67) according to energy dispersive X-ray spectroscopy analysis. In vitro cell culture experiments indicated that the EHSS/HAp with 70% SPI content showed improved cytocompatibility and was suitable for MC3T3-E1 cell attachment, proliferation and growth. Consistently, in vitro osteogenic differentiation studies showed that EHSS/HAp with 70% SPI content can significantly accelerate the expression of osteogenesis-related genes (Col-1, Runx2, OPN, and OCN) during osteogenic differentiation of MC3T3-E1 cells. Furthermore, when applied to the repair of critical-sized cranial defects in a rat model, EHSS/HAp with 70% SPI was capable of significantly promoting tissue regeneration and integration with native bone tissue. Microscopic computed tomography (micro-CT) results demonstrated that the bone defect site was nearly occupied with newly formed bone at 12 weeks after implantation of EHSS/HAp with 70% SPI content into the defect. Hematoxylin and eosin (H&E) staining and Masson's trichrome staining of histological sections further confirmed that EHSS/HAp with 70% SPI markedly promoted new bone formation and maturation. Collectively, our results demonstrate the potential of EHSS/HAp scaffolds with 70% SPI for successful bone defect repair and regeneration.

Macrolactin A protects against LPS-induced bone loss by regulation of bone remodeling

An imbalance between bone resorption and bone formation leads to several kinds of bone diseases such as rheumatoid arthritis, osteoporosis and Paget's disease. The imbalance between bone formations relative to bone resorption is responsible in bone remodeling. Several studies have suggested that macrolactin A (MA) has potent anti-inflammatory, anti-cancer and anti-angiogenic effects in various cell types. We investigate whether macrolactin A (MA) could inhibit bone loss and enhance bone formation. We used bone marrow monocytes/macrophages (BMMs) cells to study osteoclast activity and MC3T3-E1 cells to study osteoblast activity. MA suppressed tartrate resistant acid phosphatase (TRAP) positive multinucleated cells in a concentration-dependent manner, as well as at a specific time point. MA markedly reduced bone resorption activity and F-actin ring formation. Moreover, MA markedly suppressed receptor activator of nuclear factor k-B ligand (RANKL)-induced osteoclastogenic marker genes and transcription factors in-vitro. MA repressed osteoclast differentiation via activation of the phosphoinositide kinase-3/Akt, extracellular signal-regulated kinase 1/2 (ERK 1/2), c-Jun N-terminal kinase (JNK), nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) and c-Fos signaling pathways. MA enhanced pre-osteoblast cell differentiation on mineralization activity, alkaline phosphatase (ALP) activity, and the expression of osteoblastogenic markers including osterix, RUNX-2, SMAD4, BMP-2, and ALP. Importantly, MA repressed lipopolysaccharide (LPS)-induced inflammatory bone loss in mice as shown by TRAP staining of femurs and μCT analysis. Therefore, MA could be a promising candidate for the inhibition and management of osteoporosis, arthritis, and bone lytic diseases.

Biocatalytic Synthesis of Calycosin-7-O-β-D-Glucoside with Uridine Diphosphate–Glucose Regeneration System

Calycosin-7-O-β-D-glucoside (Cy7G) is one of the principal components of Radix astragali. This isoflavonoid glucoside is regarded as an indicator to assess the quality of R. astragali and exhibits diverse pharmacological activities. In this study, uridine diphosphate-dependent glucosyltransferase (UGT) UGT88E18 was isolated from Glycine max and expressed in Escherichia coli. Recombinant UGT88E18 could selectively and effectively glucosylate the C7 hydroxyl group of calycosin to synthesize Cy7G. A one-pot reaction by coupling UGT88E18 to sucrose synthase (SuSy) from G. max was developed. The UGT88E18–SuSy cascade reaction could recycle the costly uridine diphosphate glucose (UDPG) from cheap sucrose and catalytic amounts of uridine diphosphate (UDP). The important factors for UGT88E18–SuSy cascade reaction, including UGT88E18/SuSy ratios, different temperatures, and pH values, different concentrations of dimethyl sulfoxide (DMSO), UDP, sucrose, and calycosin, were optimized. We produced 10.5 g L−1 Cy7G in the optimal reaction conditions by the stepwise addition of calycosin. The molar conversion of calycosin was 97.5%, with a space–time yield of 747 mg L−1 h−1 and a UDPG recycle of 78 times. The present study provides a new avenue for the efficient and cost-effective semisynthesis of Cy7G and other valuable isoflavonoid glucosides by UGT–SuSy cascade reaction.

Recombinant Irisin Prevents the Reduction of Osteoblast Differentiation Induced by Stimulated Microgravity through Increasing β-Catenin Expression

Background: Irisin, a novel exercise-induced myokine, was shown to mediate beneficial effects of exercise in osteoporosis. Microgravity is a major threat to bone homeostasis of astronauts during long-term spaceflight, which results in decreased bone formation. Methods: The hind-limb unloading mice model and a random position machine are respectively used to simulate microgravity in vivo and in vitro. Results: We demonstrate that not only are bone formation and osteoblast differentiation decreased, but the expression of fibronectin type III domain-containing 5 (Fdnc5; irisin precursor) is also downregulated under simulated microgravity. Moreover, a lower dose of recombinant irisin (r-irisin) (1 nM) promotes osteogenic marker gene (alkaline phosphatase (Alp), collagen type 1 alpha-1(ColIα1)) expressions, ALP activity, and calcium deposition in primary osteoblasts, with no significant effect on osteoblast proliferation. Furthermore, r-irisin could recover the decrease in osteoblast differentiation induced by simulated microgravity. We also find that r-irisin increases β-catenin expression and partly neutralizes the decrease in β-catenin expression induced by simulated microgravity. In addition, β-catenin overexpression could also in part attenuate osteoblast differentiation reduction induced by simulated microgravity. Conclusions: The present study is the first to show that r-irisin positively regulates osteoblast differentiation under simulated microgravity through increasing β-catenin expression, which may reveal a novel mechanism, and it provides a prevention strategy for bone loss and muscle atrophy induced by microgravity.

Stilbene glycoside protects osteoblasts against oxidative damage via Nrf2/HO-1 and NF-κB signaling pathways

INTRODUCTION

Oxidative stress is currently proposed as a risk factor associated with the development and progression of osteoporosis. Here, the effect of 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glycoside (THSG) on oxidative damage was investigated in an osteoblast-like MC3T3-E1 cell model.

MATERIAL AND METHODS

In this study, MC3T3-E1 cells were treated with hydrogen peroxide (H₂O₂) (100 µM) and THSG (20, 50 and 100 μM), and alkaline phosphatase (ALP). ROS and MDA levels were measured using specific kits. Meanwhile, cell viability and apoptosis were also assessed using MTT methods and flow cytometry, respectively. Then, expression levels of Nrf2 and its downstream targets were determined using real-time PCR and western blotting, as well as the apoptosis related factors, including Bax, Bcl-2, caspase-3, and caspase-9.

RESULTS

Upon H₂O₂ treatment, cell viability was significantly decreased, while THSG clearly attenuated this decrease in a dose-dependent manner. Compared with the negative control, H₂O₂ significantly decreased ALP and increased the levels of MDA, ROS and apoptosis, while THSG markedly reversed these effects in a dose-dependent manner. Moreover, THSG was identified to reverse the elevation of caspase-3, caspase-9 and Bax and the reduction of Bcl-2 induced by H₂O₂. For the Nrf2 signaling pathway, THSG was also observed to attenuate the up-regulation of Nrf2, HO-1, and NQO1, and the down-regulation of NF-κB induced by H₂O₂.

CONCLUSIONS

THSG could significantly attenuate oxidative damage induced by H₂O₂ via the Nrf2/NF-κB signaling pathway, providing new insights for treatments of osteoporosis induced by oxidative injury.

Sialoglycoprotein from Gadous morhua eggs improve high bone turnover activity via down-regulating BMP-2/Smads and Wnt/β-catenin signal pathways

Abstract

The effect of sialoglycoprotein isolated from Gadous morhua eggs (Gm-SGP) on ovariectomized (OVX) induced osteoporosis, which is characterized by high bone turnover activity was investigated. Results revealed that Gm-SGP significantly increased bone mineral density, enhanced bone biomechanical properties and repaired the microstructure of the trabecular bone. Also, the treatment with Gm-SGP remarkably decreased biochemical marker contents or activities, such as serum BALP, PICP, BMP-2, TrACP, Cath-K, urine Ca and P, leading to the reduction in bone turnover. The elevation in the rate of bone formative process contributed in the increase of bone turnover. Both BMP-2/Smads and Wnt/β-catenin signaling pathways played an important role in osteogenesis. Gm-SGP suppressed the key factors expression in these two pathways such as BMP-2, Smad1, Smad4, Lrp-5b, Runx2, Osx, ALP, Col1, OCN and β-catenin. These findings might provide some theoretical basis for the application of Gm-SGP as a potential anti-osteoporotic drug or as functional food.

Graphical Abstract

GDF11/BMP11 activates both smad1/5/8 and smad2/3 signals but shows no significant effect on proliferation and migration of human umbilical vein endothelial cells

GDF11/BMP11, a member of TGF-β superfamily, was reported to rejuvenate heart, skeletal muscle and blood vessel architecture in aged mice. However, the rejuvenative effects of GDF11 were questioned recently. Here, we investigated the effects of GDF11 on smad and non-smad signals in human umbilical vein endothelial cells (HUVECs) and the effects of GDF11 on proliferation and migration of HUVECs and primary rat aortic endothelial cells (RAECs). GDF11 factor purchased from two different companies (PeproTech and R&D Systems) was comparatively studied. Western blot was used to detect the protein expressions. The cell viability and migration were examined by using MTT and wound healing assays. Results showed that GDF11 activated both smad1/5/8 and smad2/3 signals in HUVECs. GDF11 increased protein expression of NADPH oxidase 4(NOX4) in HUVECs. GDF11 showed no significant effect on the protein level of p38, p-p38, ERK, p-ERK, Akt, p-Akt (Ser473) and p-Akt(Thr308), but increased the protein level of p-JNK and p-AMPK in HUVECs, and these increases were inhibited by antioxidant mitoTEMPO treatment. GDF11 slightly increased cell viability after short-term treatment and slightly decreased cell viability after long-term treatment. GDF11 showed no significant effect on cell proliferation and migration. These data indicated that the notion of GDF11 as a rejuvenation-related factor for endothelial cells needs to be cautious.

Hypermethylation of the CHRDL1 promoter induces proliferation and metastasis by activating Akt and Erk in gastric cancer

CHRDL1 (Chordin-like 1) is a secreted protein that acts as an antagonist of bone morphogenetic protein (BMP). BMP plays a role as an activator of BMP receptor II (BMPR II), which mediates extracellular to intracellular signal transmission and is involved in carcinogenesis and metastasis. Herein, we report that CHRDL1 expression was significantly down-regulated in gastric cancer tissues and associated with poor survival. Clinic-pathological parameters demonstrated a close relationship between low CHRDL1 expression and metastasis. In vitro, CHRDL1 knockdown promoted tumor cell proliferation and migration through BMPR II by activating Akt, Erk and β-catenin. Furthermore, we observed the hypermethylation of the CHRDL1 promoter in gastric cancer, which induced low expression of CHRDL1 and decreased its secretion to the supernatant. Finally, in vivo experiments confirmed that CHRDL1 acted as a tumor suppressor gene in suppressing tumor growth and metastasis.

Macrolactin F inhibits RANKL-mediated osteoclastogenesis by suppressing Akt, MAPK and NFATc1 pathways and promotes osteoblastogenesis through a BMP-2/smad/Akt/Runx2 signaling pathway

The balance between bone formation and bone resorption is maintained by osteoblasts and osteoclasts. In the current study, macrolactin F (MF) was investigated for novel biological activity on the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclastogenesis in primary bone marrow-derived macrophages (BMMs). We found that RANKL-induced osteoclast formation and differentiation from BMMs was significantly inhibited by MF in a dose-dependent manner without cytotoxicity. RANKL-induced F-actin ring formation and bone resorption activity in BMMs which was attenuated by MF. In addition, MF suppressed the expression of osteoclast-related genes, including c-myc, RANK, tartrate-resistant acid phosphatase (TRAP), nuclear factor of activated T cells c1 (NFATc1), cathepsin K and matrix metalloproteinase 9 (MMP9). Furthermore, the protein expression NFATc1, c-Fos, MMP9, cathepsin K and phosphorylation of Jun N-terminal kinase (JNK), p38 and Akt were also down-regulated by MF treatment. Interestingly, MF promoted pre-osteoblast cell differentiation on Alizarin Red-mineralization activity, alkaline phosphatase (ALP) activity, and the expression of osteoblastogenic markers including Runx2, Osterix, Smad4, ALP, type I collagen alpha 1 (Col1α), osteopontin (OPN), and osteocalcin (OCN) via activation of the BMP-2/smad/Akt/Runx2 pathway on MC3T3-E1. Taken together, these results indicate that MF may be useful as a therapeutic agent to enhance bone health and treat osteoporosis.

Gene expression and pathway analysis of CTNNB1 in cancer and stem cells

AIM

To investigate β-catenin (CTNNB1) signaling in cancer and stem cells, the gene expression and pathway were analyzed using bioinformatics.

METHODS

The expression of the catenin β 1 (CTNNB1) gene, which codes for β-catenin, was analyzed in mesenchymal stem cells (MSCs) and gastric cancer (GC) cells. Beta-catenin signaling and the mutation of related proteins were also analyzed using the cBioPortal for Cancer Genomics and HOMology modeling of Complex Structure (HOMCOS) databases.

RESULTS

The expression of the CTNNB1 gene was up-regulated in GC cells compared to MSCs. The expression of EPH receptor A8 (EPHA8), synovial sarcoma translocation chromosome 18 (SS18), interactor of little elongation complex ELL subunit 1 (ICE1), patched 1 (PTCH1), mutS homolog 3 (MSH3) and caspase recruitment domain family member 11 (CARD11) were also shown to be altered in GC cells in the cBioPortal for Cancer Genomics analysis. 3D complex structures were reported for E-cadherin 1 (CDH1), lymphoid enhancer binding factor 1 (LEF1), transcription factor 7 like 2 (TCF7L2) and adenomatous polyposis coli protein (APC) with β-catenin.

CONCLUSION

The results indicate that the epithelial-mesenchymal transition (EMT)-related gene CTNNB1 plays an important role in the regulation of stem cell pluripotency and cancer signaling.

Regulation of CTNNB1 signaling in gastric cancer and stem cells

Recent research has shown that the alteration of combinations in gene expression contributes to cellular phenotypic changes. Previously, it has been demonstrated that the combination of cadherin 1 and cadherin 2 expression can identify the diffuse-type and intestinal-type gastric cancers. Although the diffuse-type gastric cancer has been resistant to treatment, the precise mechanism and phenotypic involvement has not been revealed. It may be possible that stem cells transform into gastric cancer cells, possibly through the involvement of a molecule alteration and signaling mechanism. In this review article, we focus on the role of catenin beta 1 (CTNNB1 or β-catenin) and describe the regulation of CTNNB1 signaling in gastric cancer and stem cells.

Traditional Chinese medicine formulas for the treatment of osteoporosis: Implication for antiosteoporotic drug discovery

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoporosis is a chronic epidemic which can leads to enhanced bone fragility and consequent an increase in fracture risk. Traditional Chinese medicine (TCM) formulas have a long history of use in the prevention and treatment of osteoporosis. Antiosteoporotic TCM formulas have conspicuous advantage over single drugs. Systematic data mining of the existing antiosteoporotic TCM formulas database can certainly help the drug discovery processes and help the identification of safe candidates with synergistic formulations. In this review, the authors summarize the clinical use and animal experiments of TCM formulas and their mechanism of action, and discuss the potential antiosteoporotic activity and the active constituents of commonly used herbs in TCM formulas for the therapy of osteoporosis.

MATERIALS AND METHODS

The literature was searched from Medline, Pubmed, ScienceDirect, Spring Link, Web of Science, CNKI and VIP database from 1989 to 2015, and also collected from Chinese traditional books and Chinese Pharmacopoeia with key words such as osteoporosis, osteoblast, osteoclast, traditional Chinese medicine formulas to identify studies on the antiosteoporotic effects of TCM formulas, herbs and chemical constituents, and also their possible mechanisms.

RESULTS

Thirty-three TCM formulas were commonly used to treat osteoporosis, and showed significant antiosteoporotic effects in human and animal. The herb medicines and their chemical constituents in TCM formulas were summarized, the pharmacological effects and chemical constituents of commonly used herbs in TCM formulas were described in detail. The action mechanisms of TCM formulas and their chemical constituents were described. Finally, the implication for the discovery of antiosteoporotic leads and combinatory ingredients from TCM formulas were prospectively discussed.

CONCLUSIONS

Clinical practice and animal experiments indicate that TCM formulas provide a definite therapeutic effect on osteoporosis. The active constituents in TCM formulas are diverse in chemical structure, and include flavonoids, lignans, saponins and iridoid glycosides. Antiosteoporotic mechanism of TCM formulas and herbs involves multi regulatory pathways, such as Wnt/β-catenin, BMP/Smad, MAPK pathway and RANKL/OPG system. Phytochemicals from TCM formulas and their compositional herb medicines offer great potential for the development of novel antiosteoporotic drugs. The active ingredients in TCM formulas can be developed in combination as potent drugs, which may exhibit better antiosteoporotic effects compared to the individual compound.