Ugonin K-stimulated osteogenesis involves estrogen receptor-dependent activation of non-classical Src signaling pathway and classical pathway

Evaluation of the effect of co-transplantation of collagen-hydroxyapatite bio-scaffold containing nanolycopene and human endometrial mesenchymal stem cell derived exosomes to regenerate bone in rat critical size calvarial defect

This study aimed to evaluate the effect of nanoparticles based on the PLGA and biomolecule of lycopene (i.e. NLcp) and exosomes loaded on hydroxyapatite/collagen-based scaffolds (HA/Coll), on human endometrial MSCs (hEnMSCs) differentiation into osteoblast cells. To this end, after synthesizing NLcp and isolating hEnMSC-derived exosomes, and studying their characterizations, HA/Coll scaffold with/without NLcp and exosome was fabricated. In following, the rat skull-defect model was created on 54 male Sprague-Dawley rats (12 weeks old) which were classified into 6 groups [control group (4 healthy rats), negative control group: bone defect without grafting (10 rats), and experimental groups including bone defect grafted with HA/Coll scaffold (10 rats), HA/Coll/NLcp scaffold (10 rats), HA/Coll scaffold + exosome (10 rats), and HA/Coll-NLcp scaffold + exosome (10 rats)]. Finally, the grafted membrane along with its surrounding tissues was removed at 90 days after surgery, to assess the amount of defect repair by Hematoxylin and eosin staining. Moreover, immunohistochemical and X-ray Micro-Computed Tomography (Micro-CT) analyses were performed to assess osteocalcin and mean bone volume fraction (BVF). Based on the results, although, the existence of the exosome in the scaffold network can significantly increase mean BVF compared to HA/Coll scaffold and HA/Coll-NLcp scaffold (2.25-fold and 1.5-fold, respectively). However, the combination of NLcp and exosome indicated more effect on mean BVF; so that the HA/Coll-NLcp scaffold + exosome led to a 15.95 % increase in mean BVF than the HA/Coll scaffold + exosome. Hence, synthesized NLcp in this study can act as a suitable bioactive to stimulate the osteogenic, promotion of cell proliferation and its differentiation when used in the polymer scaffold structure or loaded into polymeric carriers containing the exosome.

Ugonin L inhibits osteoclast formation and promotes osteoclast apoptosis by inhibiting the MAPK and NF-κB pathways

Bone loss is a major issue for patients with osteoporosis, arthritis, periodontitis, and bone metastasis; however, anti-resorption drugs used to treat bone loss have been linked to a variety of adverse effects. Helminthostachys zeylanica (L.) Hook, belonging to the family Ophioglossaceae, is commonly used in traditional Chinese medicine to treat inflammation and liver problems. In the current study, ugonin L extracted from H. zeylanica was shown to reduce the receptor activator of nuclear factor kappa beta ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells in a concentration-dependent manner. Ugonin L treatment also inhibited the mRNA expression of osteoclast markers. Ugonin L was also shown to promote cell apoptosis in mature osteoclasts and suppress RANKL-induced ERK, p38, JNK, and NF-κB activation. Taken together, ugonin L appears to be a promising candidate for the development of novel anti-resorption therapies.

Effect of the traditional Chinese herb Helminthostachys zeylanica on postsurgical recovery in patients with ankle fracture: A double-blinded randomized controlled clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Helminthostachys zeylanica (HZ), which is also called "Dao-Di-U-Gon" in Taiwan, has anti-inflammatory and antiedema effects and is commonly used to treat edema in patients with fractures. The ugonin K component of HZ can induce osteogenesis and promote bone mineralization, its therapeutic effect, however, its therapeutic effect remains unclear. Therefore, the purpose of the present study was to investigate the effect of HZ on functional recovery in patients with ankle fractures requiring surgical treatment.

METHODS

A double-blinded, randomized, controlled study was conducted. A total of 45 patients with ankle fractures requiring surgical treatment were assigned to either the control group (n = 23 patients), which received the oral administration of HZ placebo 1.0 g t.i.d. for 42 days continuously, or to the treatment group (22 patients), which received HZ for 42 days.

RESULTS

The serum amino-terminal propeptide of type 1 procollagen (PINP) levels were similar in the first assessment (V1) between the control (45.90 ± 16.31 ng/mL) and treatment groups (52.61 ± 21.02 ng/mL; p = 0.240); the differences in PINP level between the third assessment (V3) and V1 were greater in the treatment group (35.84 ± 24.56 ng/mL) than in the control group (16.34 ± 11.97 ng/mL; p = 0.002). Radiographic healing time (RHT) was 9.09 ± 1.15 weeks in the treatment group, which was shorter than the 9.91 ± 0.79 weeks (p = 0.012) in the control group.

CONCLUSION

Oral administration of HZ for 42 days can increase serum PINP level and reduce the RHT. Therefore, HZ can be used to treat patients with ankle fractures requiring surgical treatment. However, a larger sample size is needed in future studies.

Research Progress of Natural Small-Molecule Compounds Related to Tumor Differentiation

Tumor differentiation is a therapeutic strategy aimed at reactivating the endogenous differentiation program of cancer cells and inducing cancer cells to mature and differentiate into other types of cells. It has been found that a variety of natural small-molecule drugs can induce tumor cell differentiation both in vitro and in vivo. Relevant molecules involved in the differentiation process may be potential therapeutic targets for tumor cells. Compared with synthetic drugs, natural small-molecule antitumor compounds have the characteristics of wide sources, structural diversity and low toxicity. In addition, natural drugs with structural modification and transformation have relatively concentrated targets and enhanced efficacy. Therefore, using natural small-molecule compounds to induce malignant cell differentiation represents a more targeted and potential low-toxicity means of tumor treatment. In this review, we focus on natural small-molecule compounds that induce differentiation of myeloid leukemia cells, osteoblasts and other malignant cells into functional cells by regulating signaling pathways and the expression of specific genes. We provide a reference for the subsequent development of natural small molecules for antitumor applications and promote the development of differentiation therapy.

PDGFRα reporter activity identifies periosteal progenitor cells critical for bone formation and fracture repair

The outer coverings of the skeleton, which is also known as the periosteum, are arranged in concentric layers and act as a reservoir for tissue-specific bone progenitors. The cellular heterogeneity within this tissue depot is being increasingly recognized. Here, inducible PDGFRα reporter animals were found to mark a population of cells within the periosteum that act as a stem cell reservoir for periosteal appositional bone formation and fracture repair. During these processes, PDGFRα reporter⁺ progenitors give rise to Nestin⁺ periosteal cells before becoming osteoblasts and osteocytes. The diphtheria toxin-mediated ablation of PDGFRα reporter⁺ cells led to deficits in cortical bone formation during homeostasis and a diminutive hard callus during fracture repair. After ossicle transplantation, both mouse PDGFRα reporter⁺ periosteal cells and human Pdgfrα⁺ periosteal progenitors expand, ossify, and recruit marrow to a greater extent than their counterpart periosteal cells, whereas PDGFRα reporter⁻ periosteal cells exhibit a predisposition to chondrogenesis in vitro. Total RNA sequencing identified enrichment of the secreted factors Fermt3 and Ptpn6 within PDGFRα reporter⁺ periosteal cells, which partly underlie the osteoblastogenic features of this cell population.

Helminthostachys zeylanica alleviates hepatic steatosis and insulin resistance in diet-induced obese mice

Background

Obesity and its associated health conditions, type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD), are worldwide health problems. It has been shown that insulin resistance is associated with increased hepatic lipid and causes hepatic steatosis through a myriad of mechanisms, including inflammatory signaling.

Methods

Helminthostachys zeylanica (HZ) is used widely as a common herbal medicine to relieve fever symptoms and inflammatory diseases in Asia. In the present study, we evaluated whether HZ has therapeutic effects on obesity, NAFLD and insulin resistance. The protective effects of HZ extract were examined using free fatty acid-induced steatosis in human HuS-E/2 cells and a high-fat diet-induced NAFLD in mice.

Results

The major components of the HZ extract are ugonins J and K, confirmed by HPLC. Incubation of human hepatocytes, HuS-E/2 cells, with palmitate markedly increased lipid accumulation and treatment with the HZ extract significantly decreased lipid deposition and facilitated AMPK and ACC activation. After 12 weeks of a high-fat diet with HZ extract treatment, the HFD mice were protected from hyperlipidemia and hyperglycemia. HZ extract prevented body weight gain, adipose tissue expansion and adipocyte hypertrophy in the HFD mice. In addition, fat accumulation was reduced in mice livers. Moreover, the insulin sensitivity-associated index, which evaluates insulin function, was also significantly restored.

Conclusions

These results suggest that HZ has a promising pharmacological effect on high-fat diet-induced obesity, hepatic steatosis and insulin resistance, which may have the potential for clinical application.

Advances in differentiation therapy for osteosarcoma

Differentiation therapy involves the use of agents that can induce differentiation in cancer cells, with the irreversible loss of tumour phenotype. The application of differentiation therapy in osteosarcoma has made progress because of a better understanding of the potential links between differentiation defects and tumorigenesis. Here, we review recent studies on differentiation therapy for osteosarcoma, describing a variety of differentiation inducers. By highlighting these examples of drug-induced osteosarcoma cell differentiation, we can acquire unique insights into not only osteosarcoma treatment, but also novel approaches to transform differentiating drugs into more effective therapies for other solid tumours.

Isolated Compounds from Turpinia formosana Nakai Induce Ossification

Bone metabolism is a homeostatic process, imbalance in which leads to the onset of diseases such as osteoporosis and osteopenia. Although several drugs are currently available to treat such conditions, they are associated with severe side effects and do not enhance bone formation. Thus, identifying alternative treatment strategies that focus on enhancing bone formation is essential. Herein, we explored the osteogenic potential of Turpinia formosana Nakai using human osteoblast (HOb) cells. The plant extract was subjected to various chromatographic techniques to obtain six compounds, including one new compound: 3,3′-di-O-methylellagic acid-4-O-α-l-arabinofuranoside (1). Compounds 3,3′-di-O-methylellagic acid-4-O-α-l-arabinofuranoside (1), gentisic acid 5-O-β-d-(6′-O-galloyl) glucopyranoside (2), strictinin (3), and (-)-epicatechin-3-O-β-d-allopyranoside (6) displayed no significant cytotoxicity toward HOb cells, and thus their effects on various osteogenic markers were analyzed. Results showed that 1–3 and 6 significantly increased alkaline phosphatase (ALP) activity up to 120.0, 121.3, 116.4, and 125.1%, respectively. Furthermore, 1, 2, and 6 also markedly enhanced the mineralization process with respective values of up to 136.4, 118.9, and 134.6%. In addition, the new compound, 1, significantly increased expression levels of estrogen receptor-α (133.4%) and osteogenesis-related genes of Runt-related transcription factor 2 (Runx2), osteopontin (OPN), bone morphogenetic protein (BMP)-2, bone sialoprotein (BSP), type I collagen (Col-1), and brain-derived neurotropic factor (BDNF) by at least 1.5-fold. Our results demonstrated that compounds isolated from T. formosana possess robust osteogenic potential, with the new compound, 1, also exhibiting the potential to enhance the bone formation process. We suggest that T. formosana and its isolated active compounds deserve further evaluation for development as anti-osteoporotic agents.

Hepatoprotective Effect of Ugonin M, A Helminthostachyszeylanica Constituent, on Acetaminophen-Induced Acute Liver Injury in Mice

The present study aimed to discover the possible effectiveness of Ugonin M, a unique flavonoid isolated from Helminthostachys zeylanica-a traditional Chinese medicine used as anti-inflammatory medicine-and to elucidate the potential mechanisms of Ugonin M in the acute liver injury induced by acetaminophen (APAP). In this study, Ugonin M significantly ameliorated APAP-induced histopathological changes and the typical liver function biomarkers (i.e., alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (T-Bil)). It also affected APAP-induced abnormal lipid metabolism including total cholesterol (TC) and triglyceride (TG) in the serum. In inflammatory pharmacological action, Ugonin M suppressed the pro-inflammatory mediators such as nitric oxide (NO) and the lipid peroxidation indicator malondialdehyde (MDA). In addition, Ugonin M reinforced hemeoxygenase-1 (HO-1) protein expression and the production of antioxidant enzymes viz superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). Furthermore, inflammation-associated cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β as well as proteins such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were decreased by the pretreatment of Ugonin M. Moreover, this study found that pretreatment of Ugonin M apparently decreased nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) activation via inhibition of the degradation of NF-κB, inhibitory κB-α (IκB-α), extracellular regulated kinase (ERK), c-Jun-N-terminal (JNK), and p38 active phosphorylation. In conclusion, Ugonin M significantly showed a protective effect against APAP-induced liver injury by reducing oxidative stress and inflammation. Thus, Ugonin M could be one of the effective components of H. zeylanica that plays a major role in the treatment of inflammatory disorders.

Icaritin induces MC3T3-E1 subclone14 cell differentiation through estrogen receptor-mediated ERK1/2 and p38 signaling activation

Icaritin (ICT), a hydrolytic product of icariin from the genus Epimedium, has many indicated pharmacological and biological activities. Several studies have shown that ICT has potential osteoprotective effects, including stimulation of osteoblast differentiation and inhibition of osteoclast differentiation. However, the molecular mechanism for this anabolic action of ICT remains largely unknown. Here, we found that ICT could enhance MC3T3-E1 subclone 14 preosteoblastic cell differentiation associated with increased mRNA levels and protein expression of the differentiation markers alkaline phosphatase (ALP), type 1 collagen (COL1), osteocalcin (OC), osteoponin (OPN) and runt-related transcription factor 2 (RUNX2), and improved mineralization, confirmed by bone nodule formation and collagen synthesis. To characterize the underlying mechanisms, we examined the effect of ICT on estrogen receptor (ER) and mitogen-activated protein kinase (MAPK) signaling. ICT treatment induced p38 kinase and extracellular signal-regulated kinase 1/2 (ERK1/2) activation, but it demonstrated at the same time point no effect on activation of c-Jun N-terminal kinase (JNK). ER antagonist ICI182780, p38 antagonist SB203580 and ERK1/2 antagonist PD98059 markedly inhibited the ICT-induced the mRNA expression of ALP, COL1, OC and OPN. ICI182780 attenuated the ICT-induced phosphorylation of p38 and ERK1/2. These observations indicate a potential mechanism of osteogenic effects of ICT involving the ERK1/2 and p38 pathway activation through the ER.

Quality Control of the Root and Rhizome of Helminthostachys zeylanica (Daodi-Ugon) by HPLC Using Quercetin and Ugonins as Markers

Daodi-Ugon is the dried root and rhizome of Helminthostachys zeylanica (L.) Hook. and has been used for centuries in the treatment of inflammation, fever, pneumonia, burns, and various disorders. However, the chromatographic methods to determine the phytochemical composition of H. zeylanica have never been reported. This study not only aims to develop a valid high-performance liquid chromatography (HPLC) method and to establish a chromatographic fingerprint for the quality control of H. zeylanica, it also establish the proposed content limits of Quercetin, Ugonin J, and Ugonin M. An HPLC method with a RP₁₈ column (250 × 4.6 mm, 5 μm) was developed for the quantitative analysis of Quercetin, Ugonin J, and Ugonin M in H. zeylanica. A simple gradient of (A) methanol/(B) phosphoric acid in water (5–45 min, 70–80% A; 50–55 min, 80–70% A) was used and 360 nm was selected as the detection wavelength. The average contents and proposed content limits for H. zeylanica were calculated with a t-test and a measurement uncertainty test based on 20 batches of authentic H. zeylanica samples. Limits of detection (LOD), quantification (LOQ), linearity, precision, repeatability, stability, and recovery of the developed method were validated. All of the validation results of quantitative determination and fingerprinting methods were satisfactory. The developed method was then applied to assay the contents of Quercetin, Ugonin J, and Ugonin M and to acquire the fingerprints of all of the collected H. zeylanica samples. At the 99% confidence level, the calculated content limits were 56.45, 112.15, and 277.98 mg/kg for Quercetin, Ugonin J, and Ugonin M, respectively. Those validated HPLC quantitative method, fingerprinting profile, and the proposed content limits of three chemical markers that could be used in the quality control of H. zeylanica in the market.

Ugonin M, a Helminthostachys zeylanica Constituent, Prevents LPS-Induced Acute Lung Injury through TLR4-Mediated MAPK and NF-κB Signaling Pathways

Helminthostachys zeylanica (L.) Hook. is plant that has been used in traditional Chinese medicine for centuries for the treatment of inflammation, fever, pneumonia, and various disorders. The aims of the present study are to figure out the possible effectiveness of the component Ugonin M, a unique flavonoid isolated from H. zeylanica, and to elucidate the mechanism(s) by which it works in the LPS-induced ALI model. In this study, Ugonin M not only inhibited the production of pro-inflammatory mediators such as NO, TNF-α, IL-1β, and IL-6, as well as infiltrated cellular counts and protein content in the bronchoalveolar lavage fluid (BALF) of lipopolysaccharides (LPS)-induced acute lung injury (ALI) mice, but also ameliorated the severity of pulmonary edemas through the score of a histological examination and the ratio of wet to dry weight of lung. Moreover, Ugonin M was observed to significantly suppress LPS-stimulated protein levels of iNOS and COX-2. In addition, we found that Ugonin M not only obviously suppressed NF-κB and MAPK activation via the degradation of NF-κB and IκB-α as well as ERK and p38MAPK active phosphorylation but also inhibited the protein expression level of TLR4. Further, Ugonin M treatment also suppressed the protein levels of MPO and enhanced the protein expressions of HO-1 and antioxidant enzymes (SOD, GPx, and CAT) in lung tissue of LPS-induced ALI mice. It is anticipated that through our findings, there is strong evidence that Ugonin M may exert a potential effect against LPS-induced ALI mice. Hence, Ugonin M could be one of the major effective components of H. zeylanica in the treatment of inflammatory disorders.

Anti-inflammatory and Antiosteoporosis Flavonoids from the Rhizomes of Helminthostachys zeylanica

Chemical investigation of the rhizomes of Helminthostachys zeylanica led to the isolation of eight new flavonoids including six cyclized geranylflavonoids, ugonins V-X (1-3), (10R,11S)-ugonin N (4), (10R,11S)-ugonin S (5), and ugonin Y (6), as well as two quercetin glucosides, quercetin-4'-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (7) and quercetin-3-O-β-d-glucopyranosyl-4'-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (8). The structures of these compounds were established by spectroscopic analyses and acid hydrolysis of the sugar moiety. Among the isolated compounds, 1, 2, 5, 6, ugonins J-S (9-13), ugonstilbene A (14), and ugonin L (23) were evaluated for their anti-inflammatory activity on lipopolysaccharide-induced nitric oxide (NO) production in microglial cells. Except for 1, 5, and 13, all other compounds inhibited NO production with IC₅₀ values of 6.2-10.1 μM and were more potent than the positive control, pyrrolidine dithiocarbamate. Compounds 1, 2, 5, 6, and 10-13 were tested for antiosteoporotic activities, and ugonin K (10) exhibited the highest inhibitory activity against RANKL-induced osteoclast differentiation in RAW264.7 cells with an IC₅₀ value of 1.8 ± 0.2 μM.

Efficacy of proline in the treatment of menopause

The amino acids in the placenta have multiple functions; however, the therapeutic effects of proline remain poorly for relief postmenopausal symptoms. The aim of present study was to evaluate the effects of proline in the treatment of menopause using in vitro and in vivo models. We assessed the therapeutic effects and regulatory mechanisms of proline by using MCF-7 estrogen-dependent cells, MG63 osteoblast cells, and ovariectomized mice model. An in vivo study was carried out in eight-week-old sham and ovariectomized group. The ovariectomized mouse was further subdivided into two groups administered orally with 17β-estradiol or proline (10 mg/kg/day) for eight weeks. Proline significantly increased cell proliferation and Ki-67 levels in MCF-7 cells and enhanced cell proliferation, alkaline phosphatase activity, extracellular signal-regulated kinase phosphorylation, and glutamyl-prolyl-tRNA synthetase activation in MG63 cells. The estrogen receptor-β and estrogen-response elements luciferase activity were significantly increased by proline in MCF-7 and MG63 cells. In ovariectomized mice, oral administration of proline (10 mg/kg/day) for eight weeks significantly reduced body and vaginal weights. Proline also significantly increased serum estradiol and alkaline phosphatase levels, whereas serum luteinizing hormone was decreased by proline. In addition, detailed microcomputed tomography analysis showed that the proline notably enhanced bone mineral density, trabecular bone volume, and trabecular number in ovariectomized mice. Those findings implied that proline can be a promising candidate for the treatment of menopause.

Evaluation of Anti-Inflammatory Effects of Helminthostachys zeylanica Extracts via Inhibiting Bradykinin-Induced MMP-9 Expression in Brain Astrocytes

Phytochemicals present in vegetables, fruits, and herbs are believed to reduce the risk of several major diseases including cardiovascular or neurodegenerative disorders. The roots of the fern Helminthostachys zeylanica (L.) Hook. (Ophioglossaceae) have been used for centuries in the treatment of inflammation and as a folk medicine in several countries. The plant has been shown to possess an array of medicinal properties, including antioxidants and anti-inflammatory activities. Moreover, a rising level of matrix metalloproteinase-9 (MMP-9) has been found in blood fluid of these patients suffering from brain inflammatory diseases, which may be considered an inflammatory biomarker in several inflammatory diseases including the central nervous system (CNS) inflammation. Previously, we have demonstrated the signaling mechanisms of bradykinin (BK)-induced MMP-9 expression in brain astrocytes. Herein, we evaluate the effects of H. zeylanica extracts on BK-induced MMP-9 expression in brain astrocytes and its influencing mechanism. The results showed that H. zeylanica extracts, including E0, E1, and E2 significantly reduce MMP-9 induced by BK in brain astrocytes (RBA-1 cells). These H. zeylanica extracts can inhibit BK-stimulated phosphorylation of c-Src, Pyk2, and PKC(α/δ). Moreover, BK-stimulated NADPH oxidase (Nox)-derived reactive oxygen species (ROS) generation has also been attenuated by pretreatment with these extracts, suggesting that the H. zeylanica extracts have an antioxidative activity. We further demonstrated that the H. zeylanica extracts blocked activation of MAPKs (e.g., ERK1/2 and p38 MAPK) by BK. These data indicated that the H. zeylanica extracts may be has anti-inflammatory activity by reducing BK-induced ROS-dependent MMP-9 expression via these related pathways in brain astrocytes.

Src enhances osteogenic differentiation through phosphorylation of Osterix

Osterix, a zinc-finger transcription factor, is required for osteoblast differentiation and new bone formation during embryonic development. The c-Src of tyrosine kinase is involved in a variety of cellular signaling pathways, leading to the induction of DNA synthesis, cell proliferation, and cytoskeletal reorganization. Src activity is tightly regulated and its dysregulation leads to constitutive activation and cellular transformation. The function of Osterix can be also modulated by post-translational modification. But the precise molecular signaling mechanisms between Osterix and c-Src are not known. In this study we investigated the potential regulation of Osterix function by c-Src in osteoblast differentiation. We found that c-Src activation increases protein stability, osteogenic activity and transcriptional activity of Osterix. The siRNA-mediated knockdown of c-Src decreased the protein levels and transcriptional activity of Osterix. Conversely, Src specific inhibitor, SU6656, decreased the protein levels and transcriptional activity of Osterix. The c-Src interacts with and phosphorylates Osterix. These results suggest that c-Src signaling modulates osteoblast differentiation at least in part through Osterix.

Identification of novel osteogenic compounds by an ex-vivo sp7:luciferase zebrafish scale assay

Tight interactions among different cell types contributing to bone formation are of key importance in the maintenance of bone homeostasis. Based on the high similarity in responses to (anti)osteogenic signals between zebrafish scales and mammalian bone, we developed and validated a model to screen large numbers of compounds using ex-vivo cultured scales of a sp7:luciferase transgenic zebrafish. This model combines the high predictive value of explant cultures with quick, sensitive, and quantifiable readout converging the effects via various pathways including WNT-signaling, to SP7/osterix promoter activity. Sp7 is pivotal in osteoblast differentiation and activity and its promoter activity provides an excellent surrogate for sp7 expression. Bmp-2a was shown to dose-dependently increase sp7-driven luciferase activity ex vivo. Next, we identified novel effects on bone for 51.7% of the compounds from a small library of WNT-signaling modulators, including a strong osteogenic effect for niclosamide. From all previously characterized compounds, the effect on bone was correctly predicted for 70% of compounds, resulting in a 7% false positive- and 21% false negative rate. The proposed sp7:luciferase zebrafish scale model is unique, powerful and efficient new tool to assess compounds with osteogenic effects, prior to further testing in rodents.

5,7-Dihydroxy-4'-methoxyisoflavone induces apoptosis by inhibiting the ERK and Akt pathways in human osteosarcoma cells

Phytoestrogens are known to prevent tumor progression by inhibiting proliferation and inducing apoptosis in cancer cells. In this study we determine the effect of 5,7-dihydroxy-4'-methoxyisoflavone, a phytoestrogen, on proliferation and apoptosis in the human osteosarcoma (OS) cell line U2OS. 5,7-Dihydroxy-4'-methoxyisoflavone dose-dependently inhibited proliferation in U2OS cells, which was accompanied by an increase of early apoptotic cells. However, 5,7-dihydroxy-4'-methoxyisoflavone had little effect on the growth and apoptosis of normal human skin fibroblast (HSF) cells. This may indicate that 5,7-dihydroxy-4'-methoxyisoflavone can selectively inhibit the proliferation of cancerous cells. Meanwhile, 5,7-dihydroxy-4'-methoxyisoflavone decreased the protein levels of phosphorylated ERK and Akt. Inactivation of these pathways was confirmed by upregulation of Bax expression and downregulation of Bcl-2 expression. Phosphorylated Akt protein levels were decreased in HSF cells only at a high concentration (80 μM) of 5,7-dihydroxy-4'-methoxyisoflavone. Together, we suggest that 5,7-dihydroxy-4'-methoxyisoflavone promotes cell death of human OS cells U2OS by induction of apoptosis, which is associated with the inhibition of ERK and Akt signaling. Thus, 5,7-dihydroxy-4'-methoxyisoflavone may have less toxicity compared to normal tissue and could be a potential therapy for OS.

A novel immunomodulatory effect of ugonin U in human neutrophils via stimulation of phospholipase C

Neutrophils have a crucial role in the immune system and are the first line of defense against pathogenic invaders. Neutrophil activation is required for their defensive function and can be induced by diverse stimuli, through either binding to cell surface receptors or direct intracellular target molecule stimulation. In this study, we found that 4″a,5″,6″,7″,8″,8″a-hexahydro-5,3',4'-trihydroxy-5″,5″,8″a-trimethyl-4H-chromeno [2″,3″:7,6]flavone (ugonin U), a flavonoid isolated from Helminthostachys zeylanica (L) Hook, significantly induced superoxide production and release in a time- and concentration-dependent manner. A series of experiments was performed to dissect the mechanism of ugonin U-induced respiratory burst in human neutrophils. Our results demonstrated that ugonin U induced a slow increase in intracellular Ca(2+), which was necessary for ugonin U-stimulated superoxide release. Use of a formyl peptide receptor (FPR) blocker, G protein inhibitor, and protein tyrosine kinase (PTK) inhibitor proved that FPR, G proteins, and PTKs were not associated with ugonin U-induced respiratory burst. Additionally, immunoblotting results revealed that ugonin U did not affect the phosphorylation of mitogen-activated protein kinases and protein tyrosine. Nevertheless, a phospholipase C (PLC) inhibitor and an inositol triphosphate (IP3) receptor antagonist considerably suppressed ugonin U-stimulated Ca(2+) mobilization and subsequent superoxide release. Ugonin U also induced an increase in intracellular IP3 formation, which could be blocked using a PLC inhibitor. In conclusion, our study reveals that ugonin U represents the first identified natural flavonoid compound to directly stimulate PLC. Moreover, ugonin U induces respiratory burst via the PLC/IP3/Ca(2+) pathway in human neutrophils.

Dioscin promotes osteoblastic proliferation and differentiation via Lrp5 and ER pathway in mouse and human osteoblast-like cell lines

Background

Dioscin, a typical steroid saponin, is isolated from Dioscorea nipponica Makino and Dioscorea zingiberensis Wright. It has estrogenic activity and many studies have also reported that dioscorea plants have an effect in preventing and treating osteoporosis. However, the molecular mechanisms underlying their effect on osteoporosis treatment are poorly understood. Therefore, the present study aims to investigate the mechanism (s) by which dioscin promotes osteoblastic proliferation and differentiation in mouse pre-osteoblast like MC3T3-E1 cells and human osteoblast-like MG-63 cells.

Results

We found that dioscin (0.25 μg/ml, 0.5 μg/ml, and 1.0 μg/ml) promoted MC3T3-E1 cells and MG-63 cells proliferation and differentiation dose dependently. Western blot analysis results showed that estrogen receptor α (ER-α), estrogen receptor β (ER-β), β-catenin and Bcl-2 protein expression increased after MC3T3-E1 cells were treated with dioscin. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis indicated that dioscin could increase the ratio of osteoprotegerin (OPG)/receptor activator of NF-κB ligand (RANKL) and up-regulate the level of Lrp5 and β-catenin. And by RNA interference analysis, we proved that the effect of dioscin increasing the ratio of OPG/RANKL was dependent on Lrp5 pathway. In addition, we also found that these effects of dioscin were abolished by ICI 182, 780 (100 nM), an antagonist of ER, indicating that an ER signaling pathway was also involved. We also found that dioscin (0.25 μg/ml, 0.5 μg/ml, and 1.0 μg/ml) induced MG-63 cells proliferation and differentiation in a dose-dependent manner. Western blot analysis results indicated that ER-α, ER-β and β-catenin protein expression increased after MG-63 cells were treated with dioscin.

Conclusions

The current study is the first to reveal that dioscin can promote osteoblasts proliferation and differentiation via Lrp5 and ER pathway.

A Special Ingredient (VtR) Containing Oligostilbenes Isolated from Vitis thunbergii Prevents Bone Loss in Ovariectomized Mice: In Vitro and In Vivo Study

Vitis thunbergii is used in Taiwan as a botanical supplement for inflammatory bone diseases. This study aims to examine its direct effect on bone metabolism. Three-month-old female mice were randomly divided into ovariectomized control (OVX), sham operated (SHAM), and ovariectomy treated with either 17 β -estradiol or a special ingredient (VtR) fractionated from an ethanol extract of V. thunbergii started two weeks after ovariectomy. VtR treatment for 8 weeks significantly ameliorated the deterioration of bone mineral density and reversed all the ovariectomy-induced changes in   μ -CT parameters. The antiosteoporotic effect of VtR accompanied decrease in serum levels of C-terminal telopeptides of type I collagen (CTx), interleukin-7, and ration of RANKL/osteoprotegerin (OPG) but rise in osteocalcin concentration. Sparse calcified microarchitecture and less alkaline-phosphatase- (ALP-) positive cells were observed at the femur and vertebral sites in OVX mice while VtR remarkably restored such variation. HPLC analysis showed (+)-vitisin-A, (-)-vitisin-B, and ampelopsin C predominated in VtR. Both (-)-vitisin B and ampelopsin C increased ALP activity and bone nodule formation in cultured osteoblasts. Instead of stimulating osteoblastogenesis, (+)-vitisin A dramatically repressed osteoclasts differentiation and bone resorption. The results suggested VtR composed of diverse components to reciprocally drive osteoblastogenesis and interdict osteoclastogenesis may serve as a potential botanic drug for osteoporosis therapy.