Kaempferide Prevents Titanium Particle Induced Osteolysis by Suppressing JNK Activation during Osteoclast Formation

Six new phenylpropanoids from Kaempferia galanga L. and their anti-inflammatory activity

Kaempferia galanga L. is an aromatic medicinal plant belonging to the Zingiberaceae family. Its rhizome has been widely used as traditional Chinese medicine and a flavor spice for a long time. In this study, six previously undescribed phenylpropanoids, including four [2+2]-cycloaddition-derived cyclobutane natural products (1-4), and two phenylpropanoids (5-6) were isolated from the rhizomes of K. galanga L. Their structures were elucidated by spectroscopic methods, single-crystal X-ray diffraction, NMR calculation, and ECD spectra calculation. These cyclobutane derivatives were isolated from K. galanga for the first time. Furthermore, compounds 1-6 were evaluated for the potential inhibitory activities on NO production and NF-κB nuclear translocation in LPS-triggered RAW 264.7 macrophages. The results showed that the isolated compounds have a moderate anti-inflammatory activity measured on their potency to inhibit NO production and the expression of iNOS and COX-2. Additionally, compound 2 effectively suppressed NF-κB nuclear translocation at a concentration of 40 μM.

Dlk2 interacts with Syap1 to activate Akt signaling pathway during osteoclast formation

Excessive osteoclast formation and bone resorption are related to osteolytic diseases. Delta drosophila homolog-like 2 (Dlk2), a member of the epidermal growth factor (EGF)-like superfamily, reportedly regulates adipocyte differentiation, but its roles in bone homeostasis are unclear. In this study, we demonstrated that Dlk2 deletion in osteoclasts significantly inhibited osteoclast formation in vitro and contributed to a high-bone-mass phenotype in vivo. Importantly, Dlk2 was shown to interact with synapse-associated protein 1 (Syap1), which regulates Akt phosphorylation at Ser473. Dlk2 deletion inhibited Syap1-mediated activation of the AktSer473, ERK1/2 and p38 signaling cascades. Additionally, Dlk2 deficiency exhibits increased bone mass in ovariectomized mice. Our results reveal the important roles of the Dlk2-Syap1 signaling pathway in osteoclast differentiation and osteoclast-related bone disorders.

Transcriptome analysis of hydrogen inhibits osteoclastogenesis of mouse bone marrow mononuclear cells

Hydrogen (H2) is a major biodegradation product of implanted magnesium (Mg) alloys that are commonly used in the healing of bone fractures. Our earlier study showed that H2 can inhibit mouse bone marrow mononuclear cell (BMMC) osteoclastogenesis during the differentiation of these cells into osteoclasts, thereby facilitating fracture healing. However, the way by which H2 inhibits osteoclastogenesis remains to be elucidated. The present study used RNA-sequencing to study the transcriptome of H2-exposed BMMCs in an osteoclast-induced environment and identified the target genes and signaling pathways through which H2 exerts its biological effects. Several upregulated genes were identified: Fos, Dusp1, Cxcl1, Reln, Itga2b, Plin2, Lif, Thbs1, Vegfa and Gadd45a. Several downregulated genes were also revealed: Hspa1b, Gm4951, F830016B08Rik, Fads2, Hspa1a, Slc27a6, Cacna1b, Scd2, Lama3 and Col4a5. These differentially expressed genes were mainly involved in osteoclast differentiation cascades, as well as PI3K-AKT, Forkhead box O (FoxO), MAPK, peroxisome proliferator-activated receptor (PPAR), TNF, TGF-β, JAK-STAT, RAS, VEGF, hypoxia-inducible factor (HIF-1) and AMPK signaling pathways. In summary, the present study revealed the key genes and signaling pathways involved in the H2-mediated inhibition of osteoclastogenesis, thereby providing a theoretical basis for the significance of H2 and an experimental basis for the application of Mg alloys in the treatment of osteoporosis.

https://elsevier.proofcentral.com/en-us/landing-page.html?token=baf280639f2773e07701834b1c13daInhibition of spermatogenesis by hypoxia is mediated by V-ATPase via the JNK/c-Jun pathway in mice

Spermatocyte apoptosis is the primary cause of a poor outcome after hypoxia-triggered spermatogenesis reduction (HSR). Vacuolar H⁺-ATPase (V-ATPase) is involved in the regulation of hypoxia-induced spermatocyte apoptosis; however, the underlying mechanism remains to be elucidated. The aim of this study was to investigate the effect of V-ATPase deficiency on spermatocyte apoptosis and the relationship between c-Jun and apoptosis in primary spermatocytes induced by hypoxia. We found that mice under hypoxia exposure for 30 days demonstrated a marked spermatogenesis reduction and downregulation of V-ATPase expression, which were assessed by a TUNEL assay and western blotting, respectively. V-ATPase deficiency resulted in more severe spermatogenesis reduction and spermatocyte apoptosis after hypoxia exposure. We also observed that silencing V-ATPase expression enhanced JNK/c-Jun activation and death receptor-mediated apoptosis in primary spermatocytes. However, inhibition of c-Jun attenuated V-ATPase deficiency-induced spermatocyte apoptosis in primary spermatocytes. In conclusion, the data in this study suggest that V-ATPase deficiency aggravated hypoxia-induced spermatogenesis reduction by promoting spermatocyte apoptosis in mice via the JNK/c-Jun pathway.

The potential role of herbal extract Wedelolactone for treating particle-induced osteolysis: an in vivo study

Background

Osteolysis is one of the most prevalent clinical complications affecting people who undergo total joint replacement (TJR). Wedelolactone (WDL) is a coumestan compound derived from the Wedelia chinensis plant and has been demonstrated to exhibit anti-inflammatory properties. This study aimed to investigate the oral administration of WDL as a potential treatment for particle-induced osteolysis using a well-established mice calvarial disease model.

Methods

Thirty-two C57BL/6 J mice were randomized into four groups: Sham, vehicle, osteolysis group with oral WDL treatment for 4 weeks (WDL 4w), and osteolysis group treated for 8 weeks (WDL 8w). Micro-CT was used to quantitatively analyze the bone mineral density (BMD), bone volume/tissue volume (BV/TV) and trabecular bone thickness (Tb.Th). Osteoclast numbers were also measured from histological slides by two investigators who were blind to the treatment used.

Results

The results from micro-CT observation showed that BMD in the WDL 8w group improved significantly over the vehicle group (p < 0.05), but there was no significant difference between WDL 4w and 8w for BV/TV and Tb.Th. Osteoclast numbers in the WDL 4w group were also lower than the vehicle group (p < 0.05), but the difference between WDL 8w and 4w groups was not significant.

Conclusions

Particle-induced osteolysis is an inevitable long-term complication after TJR. The results of this animal study indicate that an oral administration of WDL can help reduce the severity of osteolysis without adverse effects.

Metabolic Division in an Escherichia coli Coculture System for Efficient Production of Kaempferide

Kaempferide, a plant-derived natural flavonoid, exhibits excellent pharmacological activities with nutraceutical and medicinal applications in human healthcare. Efficient microbial production of complex flavonoids suffers from metabolic crosstalk and burden, which is a big challenge for synthetic biology. Herein, we identified 4'-O-methyltransferases and divided the artificial biosynthetic pathway of kaempferide into upstream, midstream, and downstream modules. By combining heterologous genes from different sources and fine-tuning the expression, we optimized each module for the production of kaempferide. Furthermore, we designed and evaluated four division patterns of synthetic labor in coculture systems by plug-and-play modularity. The linear division of three modules in a three-strain coculture showed higher productivity of kaempferide than that in two-strain cocultures. The U-shaped division by co-distributing the upstream and downstream modules in one strain led to the best performance of the coculture system, which produced 116.0 ± 3.9 mg/L kaempferide, which was 510, 140, and 50% higher than that produced by the monoculture, two-strain coculture, and three-strain coculture with the linear division, respectively. This is the first report of efficient de novo production of kaempferide in a robust Escherichia coli coculture. The strategy of U-shaped pathway division in the coculture provides a promising way for improving the productivity of valuable and complex natural products.

Zoledronic acid inhibits osteoclastogenesis and bone resorptive function by suppressing RANKL‑mediated NF‑κB and JNK and their downstream signalling pathways

Targeting excessive osteoclast differentiation and activity is considered a valid therapeutic approach for osteoporosis. Zoledronic acid (ZOL) plays a pivotal role in regulating bone mineral density. However, the exact molecular mechanisms responsible for the inhibitory effects of ZOL on receptor activator of nuclear factor (NF)-κB ligand (RANKL)-induced osteoclast formation are not entirely clear. The present study aimed to investigate the role of ZOL in osteoclast differentiation and function, and to determine whether NF-κB and mitogen-activated protein kinase, and their downstream signalling pathways, are involved in this process. RAW264.7 cells were cultured with RANKL for differentiation into osteoclasts, in either the presence or absence of ZOL. Osteoclast formation was observed by tartrate-resistant acid phosphatase staining and bone resorption pit assays using dentine slices. The expression of osteoclast-specific molecules was analysed using reverse transcription-quantitative polymerase chain reaction and western blotting assays to deduce the molecular mechanisms underlying the role of ZOL in osteoclastogenesis. The results showed that ZOL significantly attenuated osteoclastogenesis and bone resorptive capacity in vitro. ZOL also suppressed the activation of NF-κB and the phosphorylation of c-Jun N-terminal kinase. Furthermore, it inhibited the expression of the downstream factors c-Jun, c-Fos and nuclear factor of activated T cells c1, thereby decreasing the expression of dendritic cell-specific transmembrane protein and other osteoclast-specific markers. In conclusion, ZOL may have therapeutic potential for osteoporosis.

Kaempferia galanga L.: Progresses in Phytochemistry, Pharmacology, Toxicology and Ethnomedicinal Uses

K. galanga is an aromatic medicinal herb. It is locally to India and distributed in China, Myanmar, Indonesia, Malaysia, and Thailand. K. galanga is a Traditional Chinese Herb Medicine (TCHM), which has been applied to treat cold, dry cough, toothaches, rheumatism, hypertension and so on. In addition, it has been used widely as spices since its highly aromas. The aim of this review is to compile and update the current progresses of ethnomedicinal uses, phytochemistry, pharmacology and toxicology of K. galanga. All the data on K. galanga were based on different classical literary works, multiple electronic databases including SciFinder, Web of Science, PubMed, etc. The results showed that ninety-seven compounds have been identified from rhizome of K. galanga, including terpenoids, phenolics, cyclic dipeptides, flavonoids, diarylheptanoids, fatty acids and esters. Modern pharmacology studies revealed that extracts or secondary metabolites of the herb possessed anti-inflammatory, anti-oxidant, anti-tumorous, anti-bacterial, and anti-angiogenesis effects, which were closely related to its abundant ethnomedicinal uses. In conclusion, although previous research works have provided various information of K. galanga, more in-depth studies are still necessary to systemically evaluate phytochemistry, pharmacological activities, toxicity and quality control of this herb.

Activation of mitochondrial TUFM ameliorates metabolic dysregulation through coordinating autophagy induction

Disorders of autophagy, a key regulator of cellular homeostasis, cause a number of human diseases. Due to the role of autophagy in metabolic dysregulation, there is a need to identify autophagy regulators as therapeutic targets. To address this need, we conducted an autophagy phenotype-based screen and identified the natural compound kaempferide (Kaem) as an autophagy enhancer. Kaem promoted autophagy through translocation of transcription factor EB (TFEB) without MTOR perturbation, suggesting it is safe for administration. Moreover, Kaem accelerated lipid droplet degradation in a lysosomal activity-dependent manner in vitro and ameliorated metabolic dysregulation in a diet-induced obesity mouse model. To elucidate the mechanism underlying Kaem’s biological activity, the target protein was identified via combined drug affinity responsive target stability and LC–MS/MS analyses. Kaem directly interacted with the mitochondrial elongation factor TUFM, and TUFM absence reversed Kaem-induced autophagy and lipid degradation. Kaem also induced mitochondrial reactive oxygen species (mtROS) to sequentially promote lysosomal Ca²⁺ efflux, TFEB translocation and autophagy induction, suggesting a role of TUFM in mtROS regulation. Collectively, these results demonstrate that Kaem is a potential therapeutic candidate/chemical tool for treating metabolic dysregulation and reveal a role for TUFM in autophagy for metabolic regulation with lipid overload.

Kim, Hwang et al. use in vitro and in vivo models of autophagy disorder/metabolic dysfunction to show that in this context, the natural compound kaempferide is an autophagy enhancer and reveal that one of the underlying mechanisms governing this is mediated by the mitochondrial elongation factor TUFM. This insight may have therapeutic value in the treatment of metabolic disorders.

6'-O-Galloylpaeoniflorin Attenuates Osteoclasto-genesis and Relieves Ovariectomy-Induced Osteoporosis by Inhibiting Reactive Oxygen Species and MAPKs/c-Fos/NFATc1 Signaling Pathway

Emerging evidence suggests bright prospects of some natural antioxidants in the treatment of osteoporosis. 6'-O-Galloylpaeoniflorin (GPF), an antioxidant isolated from peony roots (one of very widely used Oriental medicines, with various anti-inflammatory, antitumor, and antioxidant activities), shows a series of potential clinical applications. However, its effects on osteoporosis remain poorly investigated. The current study aimed to explore whether GPF can attenuate osteoclastogenesis and relieve ovariectomy-induced osteoporosis via attenuating reactive oxygen species (ROS), and investigate the possible mechanism. After the culture of primary murine bone marrow-derived macrophages/monocytes were induced by the use of macrophage colony-stimulating factor (M-CSF) and the receptor activator of NF-κB ligand (RANKL) and then treated with GPF. Cell proliferation and viability were assessed by Cell Counting Kit-8 (CCK-8) assay. Thereafter, the role of GPF in the production of osteoclasts and the osteogenic resorption of mature osteoclasts were evaluated by tartrate-resistant acid phosphatase (TRAP) staining, podosome belt formation, and resorption pit assay. Western blotting and qRT-PCR examination were performed to evaluate proteins' generation and osteoclast-specific gene levels, respectively. The ROS generation in cells was measured in vitro by 2',7'-Dichlorodi-hydrofluorescein diacetate (DCFH-DA). Ovariectomy-induced osteoporosis mouse administered with GPF or vehicle was performed to explore the in vivo potential of GPF, then a micro-CT scan was performed in combination with histological examination for further analysis. GPF suppressed the formation of osteoclasts and podosome belts, as well as bone resorption when induced by RANKL through affecting intracellular ROS activity, MAPKs signaling pathway, and subsequent NFATc1 translocation and expression, as well as osteoclast-specific gene expression in vitro. In vivo study suggested that exposure to GPF prevented osteoporosis-related bone loss in the ovariectomized mice. These findings indicate that GPF attenuates osteoclastogenesis and relieves ovariectomy-induced osteoporosis by inhibiting ROS and MAPKs/c-Fos/NFATc1 signaling pathway. This suggested that GPF may be potentially used to treat bone diseases like periodontitis, rheumatoid arthritis, and osteoporosis associated with osteoclasts.

Low dose IL-2 suppress osteoclastogenesis in collagen-induced arthritis via JNK dependent pathway

Background

Rheumatoid arthritis (RA) is one of the most common chronic immune joint diseases, mainly involving blood vessels and small joints. The complex pathogenesis of RA greatly increases the difficulty of treatment. At present, the common hormone and immunosuppressive therapy are not effective, while low‐dose interleukin‐2 (IL‐2) recently has been found to possess some advantages for immunotherapy. However, its related signal pathway remains to be elucidated.

Methods

We fabricated the model of arthritis in mice, and then low‐dose IL‐2 was injected at a fixed time point to observe the changes of related vascular and organ pathology, inflammatory factors, and signal pathway proteins, which were verified by statistical analysis.

Results

Low dose IL‐2 can reduce the severity of vascular and bone lesions in collagen‐induced arthritis immune model, and inhibit osteoclast formation in vitro by phosphorylation of nuclear factor‐κB (NF‐κB), which inhibits the receptor activator of NF‐κB ligand effect through c‐Jun N‐terminal kinase (JNK) pathway, and its immunotherapeutic effect depends on the activation of JNK.

Conclusion

It is the first time for us to prove that low dose IL‐2 can inhibit osteoclast formation in collagen‐induced arthritis through the JNK dependent pathway, which will provide the angle and theoretical basis for future immunotherapy of IL‐2.

Kaempferide Induces G0/G1 Phase Arrest and Apoptosis via ROS-Mediated Signaling Pathways in A549 Human Lung Cancer Cells

Kaempferide is an O-methylated flavonol that has received much attention due to its various biological activities. In this study, we explored the underlying mechanisms of kaempferide in human lung cancer A549 cells. The Cell Counting Kit-8 (CCK-8) assay, Hoechst 33342/propidium iodide double staining, flow cytometry, scratch wound healing assay, and Western blot analysis were used to measure cell apoptosis, the cell cycle, reactive oxygen species (ROS) levels, and cell migration of human lung cancer cells. Kaempferide significantly inhibited human lung cancer cell proliferation, and its toxic effects on normal cells were significantly lower than those of 5-fluorouracil. Kaempferide induced A549 cell apoptosis by decreasing the mitochondrial membrane potential and the expression level of B-cell lymphoma 2, and by increasing the expression levels of Bcl-2-associated X protein and caspase-3. It also regulated mitogen-activated protein kinase (MAPK), signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) signaling pathways by increasing the expression levels of phosphorylated c-Jun N-terminal kinase, p-p38, I kappa B, and by decreasing the expression levels of phosphorylated extracellular signal-regulated kinase, p-STAT3, and NF-κB. Kaempferide induced cell cycle arrest in the G0/G1 phase in A549 cells by downregulating the expression levels of p-AKT, cyclin D1, and cyclin-dependent kinase 2. Furthermore, kaempferide blocked A549 cell migration by downregulating the expression levels of transforming growth factor beta 1 (TGF-β1), p-β-catenin, p-glycogen synthase kinase 3 beta, N-cadherin, and vimentin, and by upregulating the expression level of E-cadherin. Kaempferide enhanced the accumulation of ROS, and N-acetyl-l-cysteine (a ROS inhibitor) decreased the regulation of MAPK, NF-κB, AKT, and TGF-β signaling pathways by kaempferide, inhibited cell apoptosis, and reversed cell cycle arrest. Our results showed that kaempferide induced apoptosis via ROS-mediated MAPK, NF-κB, AKT, and TGF-β signaling pathways in A549 cells. Thus, kaempferide may be a novel drug candidate for lung cancer.

Phytochemistry, pharmacological activities and uses of traditional medicinal plant Kaempferia galanga L. - An overview

ETHNOPHARMACOLOGICAL RELEVANCE

Kaempferia galanga L. is a stemless, rhizomatous, aromatic, perennial and indigenous herb. It is native to India and distributed in China, Bangladesh, Myanmar, Sri Lanka, Japan, Thailand, Indonesia, Malaysia, Vietnam, Laos, Sudan, Nigeria and South Africa. It is an important Indian medicinal herb that has a long history of use in the treatment of several kinds of human ailments including vata ailments like cough and cold, fever, headache, pains disorders, skin diseases, rheumatic diseases, arthritis, joint fractures, vertigo, wounds, gastritis, antidote for snake venoms, inflammation, blood vomiting, mouth sores and tongue blisters in infants. Moreover, the rhizomes of this plant are highly aromatic and have been used widely as spices, in food flavoring, pickles, cosmetics and in perfumery products.

AIM OF THE REVIEW

This paper aimed to provide a critical review of current scenario on K. galanga. This review provides a current data on diversity, phytochemistry, pharmacological activities and traditional uses of K. galanga.

MATERIALS AND METHODS

The information and data on K. galanga were collated from various resources like ethnobotanical textbooks and literature databases such as PubMed, Science Direct, Wiley, Springer, Tailor and Francis, Scopus, Inflibnet, Google and Google Scholar.

RESULTS

The forty-nine phytochemicals including esters, terpenoids, flavonoids, thiourea derivatives, polysaccharides, diarylheptanoids, phenolic acids, phenolic glycoside and cyclic lipodepsipeptide have been hitherto isolated and characterized. The major bioactive compounds extracted from the rhizome of K. galanga were ethyl p-methoxycinnamate, ethyl cinnamate, kaempferol, kaempferide, kaempsulfonic acids, kaemgalangol A, xylose, cystargamide B and 3-caren-5-one. Various studies demonstrated that the K. galanga and its constituents possess several pharmacological activities like antimicrobial, antioxidant, amebicidal, analgesic, anti-inflammatory, anti-tuberculosis, anti-dengue, anti-nociceptive, anti-angiogenic, anticancer, hyperlipidemic, hypopigmentary, osteolysis, larvicidal, insecticidal and mosquito repellent, nematocidal, sedative, sniffing, vasorelaxant and wound healing.

CONCLUSION

Kaempferia galanga L. is a valuable medicinal plant which is used traditionally in India to treat a wide variety of ailments. A number of bioactive phytochemicals like esters, terpenoids, flavonoids, polysaccharides, diarylheptanoids, cyclic lipodepsipeptide, phenolic acids and glucoside have been isolated from the rhizomes of K. galanga by several researchers. These phytochemicals are highly bioactive and exhibit various pharmacological activities.

Pregnenolone Inhibits Osteoclast Differentiation and Protects Against Lipopolysaccharide-Induced Inflammatory Bone Destruction and Ovariectomy-Induced Bone Loss

Osteolytic bone disease is characterized by excessive osteoclast bone resorption leading to increased skeletal fragility and fracture risk. Multinucleated osteoclasts formed through the fusion of mononuclear precursors are the principle cell capable of bone resorption. Pregnenolone (Preg) is the grand precursor of most if not all steroid hormones and have been suggested to be a novel anti-osteoporotic agent. However, the effects of Preg on osteoclast biology and function has yet to be shown. Here we examined the effect of Preg on receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast formation and bone resorption in vitro, and potential therapeutic application in inflammatory bone destruction and bone loss in vivo. Our in vitro cellular assays demonstrated that Preg can inhibit the formation of TRAP^+ve osteoclast formation as well as mature osteoclast bone resorption in a dose-dependent manner. The expression of osteoclast marker genes CTSK, TRAP, DC-STAMP, ATP6V0d2, and NFATc1 were markedly attenuated. Biochemical analyses of RANKL-induced signaling pathways showed that Preg inhibited the early activation of extracellular regulated protein kinases (ERK) mitogen-activated protein kinase (MAPK) and nuclear factor-κB, which consequently impaired the downstream induction of c-Fos and NFATc1. Using reactive oxygen species (ROS) detection assays, we found that Preg exhibits anti-oxidant properties inhibiting the generation of intracellular ROS following RANKL stimulation. Consistent with these in vitro results, we confirmed that Preg protected mice against local Lipopolysaccharide (LPS)-induced inflammatory bone destruction in vivo by suppressing osteoclast formation. Furthermore, we did not find any observable effect of Preg on osteoblastogenesis and mineralization in vitro. Finally Preg was administered to ovariectomy (OVX)-induced bone loss and demonstrated that Preg prevented systemic OVX-induced osteoporosis. Collectively, our observations provide strong evidence for the use of Preg as anti-osteoclastogenic and anti-resorptive agent for the potential treatment of osteolytic bone conditions.

Bone-targeted PAMAM nanoparticle to treat bone metastases of lung cancer

Aim: To prepare pH-sensitive nanoparticle composed of alendronate (ALN) and poly(amidoamine) (PAMAM) to treat bone metastases of lung cancer. Methods: The solvent evaporation method was used to prepare docetaxel (DTX)-loaded ALN-PAMAM nanoparticles (DTX@ALN-PAMAM). Results: The in vitro results showed DTX@ALN-PAMAM significantly enhanced the anticancer activity of DTX and inhibited the formation of osteoclasts. DTX@ALN-PAMAM concentrated at bone metastasis site in mice, which resulted in the suppression of bone resorption, pain response and growth of bone metastases. Eventually, the therapeutic effect of DTX on bone metastases of lung cancer was obviously improved. Conclusion: ALN modified PAMAM nanoparticle could be an effective platform for the treatment of bone metastases of lung cancer.

In vitro and in vivo Biological Responses to Graphene and Graphene Oxide: A Murine Calvarial Animal Study

BACKGROUND

Graphene and its derivatives have recently gained popularity in the biomedical field. Previous studies have confirmed that both the mechanical strength and wear resistance of graphene-containing polyethylene have been greatly improved. Therefore, it is being considered as an alternative for artificial joint replacement liners. Based on the literature, the wear debris generated from the traditional polymers used for orthopedic liners could lead to particle-induced osteolysis and, consequently, failure of joint replacement. However, the biological response of this novel graphene-based polymer is still unclear. Therefore, the current study aimed to investigate the in vitro and in vivo biological effects of graphene and graphene oxide (GO) particles on bone.

MATERIALS AND METHODS

The biological responses of graphene and GO particles were tested via in vitro and murine calvarial in vivo models. In the in vitro model, murine macrophage cells were mixed with particles and hydrogel and printed into two differently designed scaffolds; the induced proinflammatory cytokines were then tested. In the murine in vivo model, the particle size distribution was measured via SEM, and these particles were then administrated in the calvarial area, referring to our established model. A micro-CT and histological analysis were performed to examine the biological effects of the particles on bone health. The data were analyzed via the one-way analysis of variance to determine the differences between the groups.

RESULTS

Both graphene and GO induced significantly higher TNF-α and IL-6 secretion compared with the control in the three-dimensional in vitro model. In the murine calvarial in vivo test, the graphene and GO particles increased the bone mass compared with the sham groups in the micro-CT analysis. Bone formation was also observed in the histological analysis.

CONCLUSION

In these in vivo and in vitro studies, the graphene and GO wear debris did not seem to induce harmful biological response effect to bone. Bone formation around the skull was observed in the calvarial model instead. Graphene-containing biomaterials could be a suitable new material for application in orthopedic prostheses due to their benefit of eliminating the risk of particle-induce osteolysis.

PP121 suppresses RANKL-Induced osteoclast formation in vitro and LPS-Induced bone resorption in vivo

Bone resorption, caused by osteoclasts (OCs), is important to bone homeostasis. The abnormalities of bone resorption may induce a series of diseases, including osteoarthritis, osteoporosis and aseptic peri-implant loosening. The latest research developed,a novel tyrosine and phosphoinositide kinase dual inhibitor, named PP121, inhibited Src in anaplastic thyroid carcinoma cell. However, the therapeutic function of PP121 on abnormal bone resorption is still uncertain. In the present study, we showed that PP121 could potently suppress osteoclast differentiation, osteoclast-specific gene expression and bone resorption via suppressing Src/MAPK (ERK and p38)/Akt-mediated NFATc1 induction in vitro. \It was found that PP121 could suppress the formation of osteoclasts from bone marrow macrophages (BMMs) without causing cytotoxicity, inhibit bone resorption and downregulate the mRNA level of osteoclast-specific markers, including calcitonin receptor (CTR), tartrate resistant acid phosphatase (TRAP), cathepsin K (CTSK), matrix metalloproteinase 3 (MMP3), Cellular oncogene fos (C-Fos) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1). Consistent with in vitro observation, we found that PP121 greatly ameliorated LPS-induced bone resorption. Our results provide promising evidence of the therapeutic potential of PP121 for osteolytic diseases related to excessive osteoclast-mediated bone resorption.

Magnesium lithospermate B inhibits titanium particles-induced osteoclast formation by c-fos and inhibiting NFATc1 expression

Purpose: Titanium particle-induced osteolysis is one of the important causes of aseptic loosening of artificial joints. Previous studies have shown the potential of natural compounds in preventing Ti particle-induced bone resorption. In this study, we observed the effects of magnesium lithospermate B (MLB) on titanium particle-induced osteoclast activity in vitro. Materials and Methods: RAW264.7 cells were treated with titanium particles (0.1 mg/mL) in the presence or absence of MLB (200 nmol/L). We evaluated the osteoclast formation, bone pits formation and tartrate-resistant acid phosphatase 5b (Tracp5b) levels. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot were used to evaluate osteoclast differentiation-related genes (TRAF6, NFATc1, and c-fos) and protein expression. Results: The number of osteoclasts, pit formation and Tracp5b levels were all the group treated with titanium particles compared to the control group (all p < 0.05). Titanium particles also promoted the expression of the TRAF6, NFATc1 and c-fos genes and protein expression. MLB significantly abolished the titanium particle-enhanced osteoclast and pits formation, and Traf6, NFATc1, and c-fos expression. Conclusions: Our data demonstrated that MLB can suppress titanium-induced osteoclast activity via inhibiting c-fos and NFATc1 expression.

Anti-Osteoporotic and Anti-Adipogenic Effects of the Water Extract of Drynaria roosii Nakaike in Ovariectomized Mice Fed a High-Fat Diet

In traditional oriental medicine, Drynaria roosii Nakaike is widely used in treating bone diseases. Postmenopausal women are strongly associated with osteoporosis and obesity. This study aimed to investigate the effects of the water extract of D. roosii (WDR) on bone loss and obesity in ovariectomized (OVX) mice fed a high-fat diet (HFD). Body weight, gonadal fat weight, histological findings, and morphometric parameters in trabecular bone were evaluated after OVX mice were treated with WDR and HFD for four weeks. The receptor activator of nuclear κ-B ligand (RANKL)-induced osteoclast differentiation in bone marrow-derived macrophages (BMMs) was examined. Phytochemical identification of WDR using ultrahigh-performance liquid chromatography-tandem mass spectrometry was performed. WDR reversed the changes in body weight gain, gonadal fat mass, and trabecular bone parameters by ovariectomy. However, ovariectomy-induced uterine atrophy was not affected by WDR. WDR decreased adipocyte size and pro-inflammatory cytokines (interleukin (IL)-1β and IL-6) in gonadal fats and lipid accumulation in the bone marrow, which were induced by ovariectomy. WDR significantly decreased RANKL-induced osteoclast differentiation in BMMs. Fifteen phytochemicals were identified in WDR: Seven and nine with anti-osteoporotic and anti-adipogenic activities, respectively. Our findings suggest that WDR may have beneficial effects on postmenopausal osteoporosis and obesity.

Nirogacestat suppresses RANKL-Induced osteoclast formation in vitro and attenuates LPS-Induced bone resorption in vivo

Bone resorption, initiated by osteoclasts (OCs), plays an essential role in bone homeostasis. The abnormalities of bone resorption may induce a series of diseases, including osteoarthritis, osteoporosis and aseptic peri-implant loosening. Nirogacestat (PF-03084014, PF), a novel gamma-secretase inhibitor, has been used in phase II clinical trial for treatment of desmoid tumor. However, whether it has the therapeutic effect on abnormal bone resorption remains to be evaluated. In this study, we investigated the role of PF in the regulation of receptor activator of nuclear factor-kB ligand (RANKL)-induced osteoclastogenesis in vitro, and the lipopolysaccharide (LPS)-induced bone resorption in vivo. It was found that PF could suppress the formation of osteoclasts from bone marrow macrophages (BMMs) without causing cytotoxicity, inhibit bone resorption and downregulate the mRNA level of osteoclast-specific markers, including calcitonin receptor (CTR), tartrate resistant acid phosphatase (TRAP), cathepsin K (CTSK), dendritic cell-specific transmembrane protein (Dc-stamp), Atp6v0d2 (V-ATPase d2) and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1). Furthermore, Notch2 signaling, as well as RANKL-induced AKT signaling was significantly inhibited in BMMs. Consistent with in vitro observation, we found that PF greatly ameliorated LPS-induced bone resorption. Taken together, our study demonstrated that PF has a great potential to be used in management of osteolytic diseases.