Berberine inhibits RANKL-induced osteoclast formation and survival through suppressing the NF-kappaB and Akt pathways

Herbal medicine Ninjinyoeito inhibits RANKL-induced osteoclast differentiation and bone resorption activity by regulating NF-κB and MAPK pathway

OBJECTIVES

Osteoporosis is a systemic bone metabolism disorder characterized by decreased bone mass and strength. Osteoclasts (OCs) are giant multinucleated cells that regulate bone homeostasis by degrading bone matrix. Excessive OC differentiation and activity can lead to serious bone metabolic disorders including osteoporosis. Current treatments, including antiresorptive drugs, exert considerable adverse effects, including jaw osteonecrosis. Herbal medicines, such as Ninjinyoeito (NYT), may also offer efficacy, but with fewer adverse effects. In this study, we investigated NYT's effects on osteoclastogenesis.

METHODS

Tartrate-resistant acid phosphatase (TRAP) staining and bone resorption assays were performed to examine NYT's effects on OC differentiation and function. OC-related gene expression at mRNA and protein levels was investigated to confirm NYT's inhibitory action against osteoclastogenesis. We also demonstrated involvement of signaling pathways mediated by IκBα and mitogen-activated protein kinases (MAPK) [extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38] and showed nuclear translocation of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) and nuclear factor kappa B (NF-κB) p65 during osteoclastogenesis.

RESULTS

TRAP staining and bone resorption assays confirmed that NYT significantly inhibited OC differentiation and function. Western blot and RT-PCR results showed that NYT ameliorated osteoclastogenesis by suppressing mRNA and protein level expression of OC-related genes. Moreover, blots and immunocytochemistry (ICC) data clarified that NYT abrogates signaling pathways mediated by IκBα and MAPK (ERK, JNK, p38), and demonstrated nuclear translocation of NFATc1 and NF-κB p65 during OC differentiation.

CONCLUSIONS

These findings suggest NYT is an alternative therapeutic candidate for treating osteoporosis.

Berberine-Encapsulated Poly(lactic-co-glycolic acid)-Hydroxyapatite (PLGA/HA) Microspheres Synergistically Promote Bone Regeneration with DOPA-IGF-1 via the IGF-1R/PI3K/AKT/mTOR Pathway

Polymer microspheres have recently shown outstanding potential for bone tissue engineering due to their large specific surface area, good porosity, injectable property, good biocompatibility, and biodegradability. Their good load-release function and surface modifiability make them useful as a carrier of drugs or growth factors for the repair of bone defects in irregularly injured or complex microenvironments, such as skull defects. In this study, berberine (BBR)-encapsulated poly(lactic-co-glycolic acid) (PLGA)/hydroxyapatite (HA) microspheres were fabricated using electrified liquid jets and a phase-separation technique, followed by modification with the 3,4-hydroxyphenalyalanine-containing recombinant insulin-like growth-factor-1 (DOPA-IGF-1). Both the BBR and the IGF-1 exhibited sustained release from the IGF-1@PLGA/HA-BBR microspheres, and the composite microspheres exhibited good biocompatibility. The results of the alkaline phosphatase (ALP) activity assays showed that the BBR and IGF-1 in the composite microspheres synergistically promoted the osteogenic differentiation of MC3T3-E1 cells. Furthermore, it was confirmed that immobilized IGF-1 enhances the mRNA expression of an osteogenic-related extracellular matrix and that BBR accelerates the mRNA expression of IGF-1-mediated osteogenic differentiation and cell mineralization. Further cellular studies demonstrate that IGF-1 could further synergistically activate the IGF-1R/PI3K/AKT/mTOR pathway using BBR, thereby enhancing IGF-1-mediated osteogenesis. Rat calvarial defect repair experiments show that IGF-1@PLGA/HA-BBR microspheres can effectively promote the complete bony connection required to cover the defect site and enhance bone defect repair. These findings suggest that IGF-1@PLGA/HA-BBR composite microspheres show a great potential for bone regeneration.

Isopsoralen suppresses receptor activator of nuclear factor kappa-β ligand-induced osteoclastogenesis by inhibiting the NF-κB signaling

Osteoporosis is a serious systemic metabolic bone system disease.This study aimed to identify the target genes of isopsoralen and the signaling pathways involved in the differential expression of the genes involved in osteoclast differentiation. We hypothesized that isopsoralen may inhibit osteoclast differentiation by blocking the nuclear factor kappa-B (NF-κB) signaling pathway and verified our hypothesis through basic experiments. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to detect the effect of isopsoralen on the proliferation and viability of primary mouse bone marrow monocytes (BMMCs). The effect of isopsoralen on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast differentiation was determined by using tartrate-resistant acid phosphatase (TRAP) staining. Quantitative real-time PCR (qRT-PCR) and Western blot were used to detect the expression of the related genes and proteins. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of isopsoralen target genes were obtained through comprehensive analysis using the STITCH database, Cytoscape 3.8.2, and R-Studio software. Differentially expressed genes (DEGs) were found in osteoclasts induced by RANKL before and after 3 days using R-Studio, following which KEGG analysis was performed. Next, enrichment analysis was performed on the KEGG pathway shared by the target genes of isopsoralen and the differentially expressed genes during osteoclast differentiation to predict the signaling pathway underlying the inhibition of osteoclast differentiation by isopsoralen. Finally, Western blot was used to detect the effect of isopsoralen on the activation of signaling pathways to verify the results of our bioinformatics analysis. Based on the enrichment analysis of isopsoralen target genes and differentially expressed genes during osteoclastogenesis, we believe that isopsoralen can inhibit RANKL-induced osteoclastogenesis by inhibiting the NF-κB signaling pathway.

Effects and mechanisms of natural alkaloids for prevention and treatment of osteoporosis

Natural alkaloids are polycyclic, nitrogen-containing, and basic compounds obtained from plants. In this review, the advances in bioactive alkaloids with respect to their chemical structures, herbal sources, and effects for the prevention and treatment of osteoporosis are discussed. Anti-osteoporosis alkaloids are classified into six categories based on the chemical structure, namely, isoquinoline alkaloids, quinolizidine alkaloids, piperidine alkaloids, indole alkaloids, pyrrolizidine alkaloids and steroidal alkaloids. They promote mesenchymal stem cells differentiation, improve osteoblast proliferation, stimulate osteoblast autophagy and suppress osteoclast formation. These natural alkaloids can regulate multiple signaling pathways, including interrupting the tumor necrosis factor receptor associated factor 6- receptor activator of nuclear factor kappa B interaction, inhibiting the nuclear factor kappa B pathway in osteoclasts, activating the p38 mitogen-activated protein kinases pathway in osteoblasts, and triggering the wingless and int-1 pathway in mesenchymal stem cells. This review provides evidence and support for novel drug and clinical treatment of osteoporosis using natural alkaloids.

Biochemometry-Based Discovery of Phenylpropanoids from Azadirachta indica Fruits as Inhibitors of In Vitro Osteoclast Formation

(1) Background: Inhibition of osteoclast differentiation is the key approach in treating osteoporosis. However, using state-of-the-art treatments such as bisphosphonates and estrogen-based therapy is usually accompanied by many side effects. As opposed to this, the use of natural products as an osteoporotic remedy delivers promising outcomes with minimal side effects. (2) Methods: In the present study, we implemented a biochemometric workflow comprising (i) chemometric approaches using NMR and mass spectrometry and (ii) cell biological approaches using an osteoclast cytochemical marker (TRAP). The workflow serves as a screening tool to pursue potential in vitro osteoclast inhibitors. (3) Results: The workflow allowed for the selective isolation of two phenylpropanoids (coniferyl alcohol and sinapyl alcohol) from the fruits of neem tree (Azadirachta indica). These two isolated phenylpropanoids showed a very promising dose-dependent inhibition of osteoclast differentiation with negligible effects in terms of cell viability. (4) Conclusion: The presented workflow is an effective tool in the discovery of potential candidates for osteoclast inhibition from complex extracts. The used biochemometric approach saves time, effort and costs while delivering precise hints to selectively isolate bioactive constituents.

Enhanced Antibacterial and Osteogenic Properties of Graphene Oxide Loaded with Berberine on Biomedical Titanium

Internal implants are widely used in most orthopedic surgeries, of which titanium and its alloys are most widely used owing to the excellent corrosiveness resistance, low elastic modulus and good biocompatibility. However, implant failure still occurs for that titanium and its alloys themselves do not own antibacterial and osteogenic properties. In this work, we successfully fabricated berberine-loaded graphene oxide (GO) on the surface of biomedical titanium and systematically investigated its capabilities of antibacteria and osteogenesis. In vitro results showed that berberine had low antibacterial activity, but GO loaded with berberine on titanium (Ber&GO@Ti) exhibited superior antibacterial activity against Staphylococcus aureus (S. aureus) with the synergistic effect of GO and berberine. Meanwhile, Ber&GO@Ti performed satisfactory cytocompatibility and was capable of promoting osteogenic differentiation of MC3T3-E1 cells. In the vivo experiment, Ber&GO@Ti showed excellent antibacterial properties and inflammatory cells e.g., neutrophils had seldom been found. No visceral toxicity had been found. This multifunctional coating showed great potential in orthopedic implants.

Dihydroartemisinin attenuates osteoclast formation and bone resorption via inhibiting the NF‑κB, MAPK and NFATc1 signaling pathways and alleviates osteoarthritis

Osteoarthritis (OA) is a chronic, progressive and degenerative disease, and its incidence is increasing on a yearly basis. However, the pathological mechanism of OA at each stage is still unclear. The present study aimed to explore the underlying mechanism of dihydroartemisinin (DHA) in terms of its ability to inhibit osteoclast activation, and to determine its effects on OA in rats. Bone marrow‑derived macrophages were isolated as osteoclast precursors. In the presence or absence of DHA, osteoclast formation was assessed by tartrate‑resistant acid phosphatase (TRAP) staining, cell viability was assessed by Cell Counting Kit‑8 assay, the presence of F‑actin rings was assessed by immunofluorescence, bone resorption was determined by bone slices, luciferase activities of NF‑κB and nuclear factor of activated T cell cytoplasmic 1 (NFATc1) were determined using luciferase assay kits, the protein levels of biomolecules associated with the NF‑κB, MAPK and NFATc1 signaling pathways were determined using western blotting, and the expression of genes involved in osteoclastogenesis were measured using reverse transcription‑quantitative PCR. A knee OA rat model was designed by destabilizing the medial meniscus (DMM). A total of 36 rats were assigned to three groups, namely the sham‑operated, DMM + vehicle and DMM + DHA groups, and the rats were administered DHA or DMSO. At 4 and 8 weeks postoperatively, the microarchitecture of the subchondral bone was analyzed using micro‑CT, the thickness of the cartilage layers was calculated using H&E staining, the extent of cartilage degeneration was scored using Safranin O‑Fast Green staining, TRAP‑stained osteoclasts were counted, and the levels of receptor activator of NF‑κB ligand (RANKL), C‑X‑C‑motif chemokine ligand 12 (CXCL12) and NFATc1 were measured using immunohistochemistry. DHA was found to inhibit osteoclast formation without cytotoxicity, and furthermore, it did not affect bone formation. In addition, DHA suppressed the expression levels of NF‑κB, MAPK, NFATc1 and genes involved in osteoclastogenesis. Progressive cartilage loss was observed at 8 weeks postoperatively. Subchondral bone remodeling was found to be dominated by bone resorption accompanied by increases in the levels of RANKL, CXCL12 and NFATc1 during the first 4 weeks. DHA was found to delay OA progression by inhibiting osteoclast formation and bone resorption during the early phase of OA. Taken together, the results of the present study demonstrated that the mechanism through which DHA could inhibit osteoclast activation may be associated with the NF‑κB, MAPK and NFATc1 signaling pathways, thereby indicating a potential novel strategy for OA treatment.

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

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

New Monoterpenoid Indoles with Osteoclast Activities from Gelsemium elegans

The well-known toxic medicine Gelsemium elegans is widely and historically used to treat bone fracture and skin ulcers by the folk people of China. Two new monoterpenoid indole alkaloids, gelselegandines D and E, together with the known analogue gelegamine A were isolated from G. elegans. Their structures were elucidated by means of spectroscopic techniques and quantum chemical calculations. All isolated compounds were tested for the effects on RANKL-induced osteoclast formation. Interestingly, gelselegandine E and gelegamine A, respectively, showed significant promoting and inhibitory activities on osteoclastogenesis, while gelselegandine D had no activity under the same concentration. This work suggested the different configurations for the carbons near the C-19/20 oxygen rings of the isolated compounds may be the key active groups on osteoclast formation and provided the evidence for the rationality as the traditional treatment for bone-related diseases of G. elegans.

Identification of Berbamine, Oxyacanthine and Rutin from Berberis asiatica as anti-SARS-CoV-2 compounds: An in silico study

Owing to the shortage of specific medicines, the global pandemic of COVID-19 caused by SARS-CoV-2 has been the greatest challenge for the science community. Researchers from all over the world developed some drugs which failed to completely suppress the contiguous disease. SARS-CoV-2 main protease (Mpro), an important component in viral pathogenesis, is considered as a prospective drug target to stop SARS-CoV-2 infection. Since identification of phytochemicals with anti-Mpro activity has been carried out to develop the potential drugs against SARS-CoV-2. Therefore, the present study was conducted to screen phytochemicals of Berberis asiatica for anti-SARS-CoV-2 activity. Through text mining, thirty phytochemicals were reported from B. asiatica, of which, three phytochemicals (Berbamine, Oxyacanthine, and Rutin) show high affinity with the SARS-CoV-2 Mpro and exhibited favorable intermolecular interactions with the catalytic residues (His41 and Cys145) and other essential residues. The molecular dynamics simulation showed that Mpro-phytochemical complexes are more stable, less fluctuating, more compact, and moderately extended than the Mpro-X77 (Reference) complex. The number of H-bonds and MMPBSA results also demonstrates that Berbamine, Oxyacanthine, and Rutin are potent Mpro inhibitors having free energy of -20.79, -33.35, and -31.12 kcal mol-1 respectively. The toxicity risk prediction supports all phytochemicals for drug-like and non-toxic nature. From the result, we propose that binding of these phytochemicals could hamper the function of Mpro. This work suggests that selected phytochemicals could be used as novel anti-COVID-19 drug candidates, and might act as novel compounds for in vitro and in vivo study.

Berberine for bone regeneration: Therapeutic potential and molecular mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Berberine is a quaternary ammonium isoquinoline alkaloid, mainly extracted from plants berberaceae, papaveraceae, ranunculaceae and rutaceae such as coptis chinensis Franch, Phellodendron chinense, and berberis pruinosa. The plants are extensively used in traditional medicine for treating infection, diabetes, arrhythmia, tumor, osteoporosis et al. Pharmacological studies showed berberine has effects of anti-inflammation, anti-tumor, lower blood lipid, lower blood glucose, anti-osteoporosis, anti-osteoarthritis et al. AIM OF THE STUDY: This review aims to summarize the application of natural herbs that contain berberine, the further use and development of berberine, the effects as well as mechanism of berberine on osteoblasts and osteoclasts, the recent advances of in vivo studies, in order to provide a scientific basis for its traditional uses and to prospect of the potential applications of berberine in clinics.

METHOD

The research was achieved by retrieving from the online electronic database, including PubMed, Web of Science, Google Scholar and China national knowledge infrastructure (CNKI). Patents, doctoral dissertations and master dissertations are also searched.

RESULTS

Berberine has a long history of medicinal use to treat various diseases including bone disease in China. Recent studies have defined its function in promoting bone regeneration and great potential in developing new drugs. But the systemic mechanism of berberine on bone regeneration still needs more research to clarify.

CONCLUSION

This review has systematically summarized the application, pharmacological effects, mechanism as well as in vivo studies of berberine and herbs which contain berberine. Berberine has a definite effect in promoting the proliferation and differentiation of osteoblasts as well as inhibiting the production of osteoclasts to promote bone regeneration. However, the present studies about the system mechanisms and pharmacological activity of berberine were incomplete. Applying berberine for new drug development remains an exciting and promising alternative to bone regeneration engineering, with broad potential for therapeutic and clinical practice.

Protective effects of berberine on senile osteoporosis in mice

INTRODUCTION

The incidence of osteoporosis is positively correlated with age. Berberine has been reported to treat osteoporosis due to its beneficial actions on bone formation. However, the direct effects of berberine on senile osteoporosis remain unclear. The present study investigated the protective effects of berberine on senile osteoporosis in mice and preliminarily evaluated its potential mechanism.

MATERIALS AND METHODS

20-month-old male C57BL/6 J mice were used as senile osteoporosis mouse model and treated with strontium ranelate (SR) or berberine or solvent control by daily gavage for 2 months. Thereafter, bone mass and microstructure parameters were assessed. Histological staining was performed to identify the osteogenic, adipogenic and osteoclastic activity of bone tissue. Moreover, role of cAMP/PKA/CREB signaling pathway in berberine affecting bone marrow mesenchymal stem cells (BMSCs) differentiation was clarified by enzyme-linked immunosorbent assay and western blot analysis.

RESULTS

The results showed that the SR-treated group displayed a high trabecular bone mass phenotype. For mice administrated with berberine, cancellous bone mass was upregulated in a dose-dependent manner, as indicated by gradually increased bone mass, trabecular bone volume fraction and trabecular number. Furthermore, berberine promotes osteogenic and inhibits adipogenic differentiation of BMSCs via cAMP/PKA/CREB signaling. Also, bone resorption effect becomes more obvious with increasing dose of berberine in vitro.

CONCLUSION

The present results suggest that berberine exerts potent bone protective effects by promoting bone formation, inhibiting marrow fat accumulation and bone resorption. This effect may be achieved through cAMP/PKA/CREB signaling pathway.

The emerging role of Interleukin 37 in bone homeostasis and inflammatory bone diseases

Interleukin 37 (IL-37) is a newly identified cytokine that belongs to the IL-1 family. Unlike other members of the IL-1 family, it has been demonstrated that IL-37 possesses anti-inflammatory characteristics in both innate and acquired immune responses. Recently, significant progress has been made in understanding the role of IL-37 in inflammatory signaling pathways. Meanwhile, IL-37 has also attracted more and more attention in bone homeostasis and inflammatory bone diseases. The latest studies have revealed that IL-37 palys an essential role in the regulation of osteoclastogenesis and osteoblastogenesis. The levels of IL-37 are abnormal in patients with inflammatory bone diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), and periodontitis. In addition, in vivo studies have further confirmed that recombinant IL-37 treatment displayed therapeutic potential in these diseases. The present review article aims to provide an overview describing the biological functions of IL-37 in bone homeostasis and inflammatory bone diseases, thus shedding new light on a novel therapeutic strategy in the future.

Efficacy of berberine in treatment of rheumatoid arthritis: From multiple targets to therapeutic potential

Rheumatoid arthritis is a systemic autoimmune disorder involved in persistent synovial inflammation. Berberine is a nature-derived alkaloid compound with multiple pharmacological activities in different pathologies, including RA. Recent experimental studies have clarified several determinant cellular and molecular targets of BBR in RA, and provided novel evidence supporting the promising therapeutic potential of BBR to combat RA. In this review, we recapitulate the therapeutic potential of BBR and its mechanism of action in ameliorating RA, and discuss the modulation of gut microbiota by BBR during RA. Collectively, BBR might be a promising lead drug with multi-functional activities for the therapeutic strategy of RA.

Berberine ameliorates the LPS-induced imbalance of osteogenic and adipogenic differentiation in rat bone marrow-derived mesenchymal stem cells

Lipopolysaccharide (LPS) from oral pathogenic bacteria is an important factor leading to alveolar bone absorption and the implant failure. The present study aimed to evaluate the modulation of berberine hydrochloride (BBR) on the LPS-mediated osteogenesis and adipogenesis imbalance in rat bone marrow-derived mesenchymal stem cells (BMSCs). Cell viability, osteoblastic and adipogenic differentiation levels were measured using the Cell Counting Kit-8 assay, alkaline phosphatase (ALP) staining and content assay, and oil red O staining, respectively. Reverse transcription-quantitative PCR and immunoblotting were used to detect the related gene and protein expression levels. In undifferentiated cells, BBR increased the mRNA expression levels of the osteoblastic genes (Alp, RUNX family transcription factor 2, osteocalcin and secreted phosphoprotein 1) but not the adipogenic genes (fatty acid binding protein 4, Adipsin and peroxisome proliferator-activated receptorγ). LPS-induced osteoblastic gene downregulation, adipogenic gene enhancement and NF-κB activation were reversed by BBR treatment. In osteoblastic differentiated cells, decreased ALP production by LPS treatment was recovered with BBR co-incubation. In adipogenic differentiated cells, LPS-mediated lipid accumulation was decreased by BBR administration. The mRNA expression levels of the pro-inflammatory factors (MCP-1, TNF-α, IL-6 and IL-1β) were increased by LPS under both adipogenic and osteoblastic conditions, which were effectively ameliorated by BBR. The actions of BBR were attenuated by compound C, suggesting that the role of BBR may be partly due to AMP-activated protein kinase activation. The results demonstrated notable pro-osteogenic and anti-adipogenic actions of BBR in a LPS-stimulated inflammatory environment. This indicated a potential role of BBR for bacterial infected-related peri-implantitis medication.

Immunomodulatory effects of berberine on the inflamed joint reveal new therapeutic targets for rheumatoid arthritis management

Rheumatoid arthritis (RA) is a chronic inflammatory syndrome designated by synovial joint inflammation leading to cartilage degradation and bone damage as well as progressive disability. Synovial inflammation is promoted through the infiltration of mononuclear immune cells, dominated by CD4+ T cells, macrophages and dendritic cells (DCs), together with fibroblast-like synoviocytes (FLS), into the synovial compartment. Berberine is a bioactive isoquinoline alkaloid compound showing various pharmacological properties that are mainly attributed to immunomodulatory and anti-inflammatory effects. Several lines of experimental study have recently investigated the therapeutic potential of berberine and its underlying mechanisms in treating RA condition. The present review aimed to clarify determinant cellular and molecular targets of berberine in RA and found that berberine through modulating several signalling pathways involved in the joint inflammation, including PI3K/Akt, Wnt1/β-catenin, AMPK/lipogenesis and LPA/LPA1 /ERK/p38 MAPK can inhibit inflammatory proliferation of FLS cells, suppress DC activation and modulate Th17/Treg balance and thus prevent cartilage and bone destruction. Importantly, these molecular targets may explore new therapeutic targets for RA treatment.

Rab11A Functions as a Negative Regulator of Osteoclastogenesis through Dictating Lysosome-Induced Proteolysis of c-fms and RANK Surface Receptors

Osteoclast differentiation and activity are controlled by two essential cytokines, macrophage colony-stimulating factor (M-CSF) and the receptor activator of nuclear factor-κB ligand (RANKL). Rab11A GTPase, belonging to Rab11 subfamily representing the largest branch of Ras superfamily of small GTPases, has been identified as one of the crucial regulators of cell surface receptor recycling. Nevertheless, the regulatory role of Rab11A in osteoclast differentiation has been completely unknown. In this study, we found that Rab11A was strongly upregulated at a late stage of osteoclast differentiation derived from bone marrow-derived macrophages (BMMs) or RAW-D murine osteoclast precursor cells. Rab11A silencing promoted osteoclast formation and significantly increased the surface levels of c-fms and receptor activator of nuclear factor-κB (RANK) while its overexpression attenuated osteoclast formation and the surface levels of c-fms and RANK. Using immunocytochemical staining for tracking Rab11A vesicular localization, we observed that Rab11A was localized in early and late endosomes, but not lysosomes. Intriguingly, Rab11A overexpression caused the enhancement of fluorescent intensity and size-based enlargement of early endosomes. Besides, Rab11A overexpression promoted lysosomal activity via elevating the endogenous levels of a specific lysosomal protein, LAMP1, and two key lysosomal enzymes, cathepsins B and D in osteoclasts. More importantly, inhibition of the lysosomal activity by chloroquine, we found that the endogenous levels of c-fms and RANK proteins were enhanced in osteoclasts. From these observations, we suggest a novel function of Rab11A as a negative regulator of osteoclastogenesis mainly through (i) abolishing the surface abundance of c-fms and RANK receptors, and (ii) upregulating lysosomal activity, subsequently augmenting the degradation of c-fms and RANK receptors, probably via the axis of early endosomes-late endosomes-lysosomes in osteoclasts.

Effect of Orento, a Traditional Japanese Medicine, on IL-6, IL-8 Secretion, Type 1 Collagen Production and Alkaline Phosphatase Secretion in the Human Osteosarcoma Cell Line Saos-2

Background: Orento, a traditional Japanese medicine, is known as Kampo medicine in Japan. We investigated the possible efficacy of Kampo medicine for periodontal disease. In this study, we examined the in vitro effects of orento on the proliferation of the inflammatory cytokines interleukin (IL)-6 and IL-8, the production of type 1 collagen, and the secretion of alkaline phosphatase (ALP) in the human osteosarcoma cell line Saos-2 (Saos-2 cells). Methods: The proliferation of Saos-2 cells was assessed by MTT assay. IL-6 and IL-8 levels, type 1 collagen production and ALP secretion were evaluated using enzyme-linked immunosorbent assay and ALP assays. Saos-2 cells were treated with or without 0.1, 1, 10, 100 and 1000 μg/mL of orento for 24 h. Results: Orento (10 μg/mL) significantly induced the proliferation of Saos-2 cells. At this concentration, orento suppressed IL-6 and IL-8 and enhanced type 1 collagen production and ALP secretion. Conclusions: These results indicate that orento controls the IL-6 and IL-8 secretion and cellular metabolism of osteoblasts, resulting in the secretion of early bone-related biomarkers.

Functional nano-vector boost anti-atherosclerosis efficacy of berberine in Apoe (-/-) mice

Atherosclerosis (AS) is the leading cause of heart attacks, stroke, and peripheral vascular disease. Berberine (BBR), a botanical medicine, has diversified anti-atherosclerotic effects but with poor absorption. The aim of this study was to develop an effective BBR-entrapped nano-system for treating AS in high-fat diet (HFD)-fed Apoe ^(-/-) mice, and also explore the possible underlying mechanisms involved. Three d-α-tocopherol polyethylene glycol (PEG) succinate (TPGS) analogues with different PEG chain lengths were synthesized to formulate BBR-entrapped micelles. HFD-fed Apoe ^(-/-) mice were administered with optimized formula (BBR, 100 mg/kg/day) orally for 5 months. The artery plaque onset and related metabolic disorders were evaluated, and the underlying mechanisms were studied. Our data showed that, BT₁₅₀₀M increased BBR deposition in liver and adipose by 107.6% and 172.3%, respectively. In the Apoe ^(-/-) mice, BT₁₅₀₀M ameliorated HFD-induced hyperlipidemia and lipid accumulation in liver and adipose. BT₁₅₀₀M also suppressed HFD-induced chronic inflammation as evidenced by the reduced liver and adipose levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β); and decreased plasma level of TNF-α, IL-6, IL-1β, interferon-γ (IFN-γ), monocyte chemotactic protein (MCP), and macrophage inflammatory factor (MIP). The mechanism study showed that BT₁₅₀₀M changed Ampk and Nf-κb gene expression, and interrupted a crosstalk process between adipocytes and macrophages. Further investigation proved that BT₁₅₀₀M decreased endothelial lesion and subsequent macrophage activation, cytokines release, as well as cholesteryl ester gathering in the aortic arch, resulting in ameliorated artery plaque build-up. Our results provide a practical strategy for treating AS using a BBR-entrapped nano-system.

Berberine and musculoskeletal disorders: The therapeutic potential and underlying molecular mechanisms

BACKGROUND

Musculoskeletal disorders are a group of disorders that affect the joints, bones, and muscles, causing long-term disability. Berberine, an isoquinoline alkaloid, has been previously established to exhibit beneficial properties in preventing various diseases, including musculoskeletal disorders.

PURPOSE

This review article aims to recapitulate the therapeutic potential of berberine and its mechanism of action in treating musculoskeletal disorders.

METHODS

A wide range of literature illustrating the effects of berberine in ameliorating musculoskeletal disorders was retrieved from online electronic databases (PubMed and Medline) and reviewed.

RESULTS

Berberine may potentially retard the progression of osteoporosis, osteoarthritis and rheumatoid arthritis. Limited studies reported the effects of berberine in suppressing the proliferation of osteosarcoma cells. These beneficial properties of berberine are mediated in part through its ability to target multiple signaling pathways, including PKA, p38 MAPK, Wnt/β-catenin, AMPK, RANK/RANKL/OPG, PI3K/Akt, NFAT, NF-κB, Hedgehog, and oxidative stress signaling. In addition, berberine exhibited anti-apoptotic, anti-inflammatory, and immunosuppressive properties.

CONCLUSION

The current evidence indicates that berberine may be effective in preventing musculoskeletal disorders. However, findings from in vitro and in vivo investigations await further validation from human clinical trial.

A natural compound (LCA) isolated from Litsea cubeba inhibits RANKL-induced osteoclast differentiation by suppressing Akt and MAPK pathways in mouse bone marrow macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Litsea cubeba (Lour.) Pers. has been traditionally used as a folk prescription for treating rheumatic diseases in China.

AIM OF THE STUDY

This study aimed to investigate the effects and underlying mechanism of LCA, a new type of dibenzyl butane lignin compound extracted from L. cubeba, on macrophage colony stimulating factor (M-CSF) plus receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation in mouse-derived bone marrow macrophages (BMMs).

MATERIAL AND METHODS

TRAP staining, TRAP enzyme activity assay and actin ring staining were applied to identify the effects of LCA on osteoclast differentiation. Protein expression of NFATc1, c-Fos and MMP-9, and phosphorylation of p65, Akt, JNK, ERK and p38 in RANKL-induced osteoclasts was determined using western blotting to investigate the underlying mechanism.

RESULTS

LCA significantly suppressed RANKL-induced osteoclast differentiation by inhibiting TRAP activity, decreasing the number of TRAP⁺ multinuclear osteoclasts and reducing the formation of F-actin ring without obvious cytotoxicity in BMMs. Moreover, LCA treatment strongly reduced protein expression of NFATc1, c-Fos and MMP-9, and attenuated the phosphorylation of p65, Akt, JNK, ERK and p38 in RANKL-stimulated BMMs.

CONCLUSIONS

LCA ameliorated RANKL-induced osteoclast differentiation via inhibition of Akt and MAPK signalings in BMMs, and may serve as a potential pro-drug for bone destruction prevention.

Artemisinin inhibits breast cancer-induced osteolysis by inhibiting osteoclast formation and breast cancer cell proliferation

In addition to being used to treat malaria, artemisinin (Art) can be used as an anti-inflammatory and antitumor agent. In this study, we evaluated the effects of Art on osteoclast formation and activation and on the development of breast cancer cells in bone. To evaluate the effect of Art on osteoclast differentiation in vitro, we treated bone marrow-derived macrophages (BMMs) with various concentrations of Art and evaluated the expression of genes and proteins involved in osteoclast formation. We also performed cell counting kit-8 assays to evaluate the toxicity of Art in BMMs and MDA-MB-231 cells. We also performed Transwell assays, wound-healing assays, colony formation assays, and cell apoptosis assays to evaluate the effect of Art in MDA-MB-231 cells. We also evaluated the effect of Art in an in vivo osteoclast bone resorption assay using a nude mouse model. We demonstrated that Art inhibits the differentiation and establishment of osteoclasts even though Art is not toxic to osteoclasts. In addition, Art reduced expression of genes involved in osteoclast formation and inhibited osteoclast bone resorption in a concentration-dependent manner. Based on our data, we believe that Art can inhibit proliferation of breast cancer cells by activating apoptosis pathways, and inhibit osteoclast formation and differentiation by inhibiting activation of cathepsin K, ATPase H+ transporting V0 subunit D2, nuclear factor of activated T cells 1, calcitonin receptor, and tartrate-resistant acid phosphatase and by inhibiting nuclear factor-κB activation.

Berberine improves advanced glycation end products‑induced osteogenic differentiation responses in human periodontal ligament stem cells through the canonical Wnt/β‑catenin pathway

The aim of the present study was to investigate the effects of advanced glycation end products (AGEs) and berberine hydrochloride (BBR) on the osteogenic differentiation ability of human periodontal ligament stem cells (hPDLSCs) in vitro, and their underlying mechanisms. hPDLSCs were subjected to osteogenic induction and were treated with AGEs or AGEs + BBR. Following varying numbers of days in culture, alkaline phosphatase (ALP) activity assays, ALP staining, alizarin red staining, ELISAs, and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analyses were performed to determine the osteogenic differentiation ability of hPDLSCs; RT‑qPCR, western blot analysis, and immunofluorescence staining were conducted to investigate the underlying mechanisms. The canonical Wnt/β‑catenin pathway inhibitor XAV‑939 and agonist CHIR‑99021 were used to determine the contribution of the canonical Wnt/β‑catenin pathway to differentiation. Treatment with AGEs resulted in reduced ALP activity and Collagen I protein levels, decreased ALP staining, fewer mineralized nodules, and downregulated expression of osteogenic‑specific genes [Runt‑related transcription factor 2 (Runx2), Osterix, ALP, osteopontin (OPN), Collagen I and osteocalcin (OCN)] and proteins (Runx2, OPN, BSP and OCN); however, BBR partially rescued the AGE‑induced decrease in the osteogenic potential of hPDLSCs. Furthermore, AGEs activated the canonical Wnt/β‑catenin signaling pathway and promoted the nuclear translocation of β‑catenin; BBR partially attenuated this effect. In addition, XAV‑939 partially rescued the AGE‑induced reduction in the osteogenic potential of hPDLSCs, whereas CHIR‑99021 suppressed the BBR‑induced increase in the osteogenic potential of hPDLSCs. The present study indicated that AGEs attenuated the osteogenic differentiation ability of hPDLSCs, in part by activating the canonical Wnt/β‑catenin pathway; however, BBR attenuated these effects by inhibiting the canonical Wnt/β‑catenin pathway. These findings suggest a role for BBR in periodontal regeneration induced by hPDLSCs in patients with diabetes mellitus.

Grapefruit juice exerts anti-osteoporotic activities in a prednisolone-induced osteoporosis rat femoral fracture model, possibly via the RANKL/OPG axis

This study aimed to shed light on the protective and therapeutic anti-osteoporotic effects and mechanisms of action of grapefruit juice (GFJ) on prednisolone-induced osteoporosis a rat femoral fracture model. We found that treating rats with GFJ before and/or after prednisolone-induced osteoporosis resulted in increased bone density, total mineral content, and calcium content to counteract the osteoporotic effects of prednisolone. In parallel, the histological and ultrastructural results of the GFJ-treated groups correlated well with enhanced breaking strength of femurs subjected to a constant load. Furthermore, GFJ treatment before and after prednisolone-induced osteoporosis decreased plasma alkaline phosphatase and tartrate-resistant acid phosphatase activities and increased the level of insulin-like growth factor 1. Mechanistically, our immunohistochemistry study showed that GFJ ameliorated prednisolone-induced osteocalcin depletion, decreased receptor activator of nuclear factor kappa-B ligand (RANKL) expression, and increased osteoprotegerin (OPG) expression. GFJ showed a beneficial anti-osteoporotic effect against prednisolone-induced osteoporosis in rats, possibly via the RANKL/OPG axis, suggesting that GFJ might be a good candidate for developing anti-osteoporotic drugs.

Berberine Accelerates Odontoblast Differentiation by Wnt/β-Catenin Activation

Berberine, a Chinese medical herbal extract, plays a key role in antidiabetic, antiangiogenesis, anti-inflammatory, antimicrobial, anticancer, and antihypercholesterolemic. Our previous studies revealed that berberine exerted odontoprotective effect by increasing odontoblast differentiation. However, the mechanisms involved in the odontoprotective effect of berberine have not been fully explored. The Wnt/β-catenin pathway is involved in odontoblast differentiation of dental pulp stem cells (DPSCs). If β-catenin is nuclear translocation, the Wnt/β-catenin pathway is activation. In this study, DPSCs were treated with or without berberine. Then, we examined the accelerative effects of berberine on odontoblast differentiation and mineralized nodules formation by real-time polymerase chain reaction, alizarin red S staining, and alkaline phosphatase staining. In addition, while treated with berberine, β-catenin translocated to the nucleus evaluated by western blot and immunofluorescent staining. Our results revealed that berberine functions as a promoter of odontoblast differentiation by promoting Wnt/β-catenin pathway, suggesting that it may be useful in guiding therapeutic strategies for the treatment of dental caries.

Berberine Suppresses RANKL-Induced Osteoclast Differentiation by Inhibiting c-Fos and NFATc1 Expression

Osteoporosis is a common disorder of bone remodeling, marked by excessive osteoclast formation. Recent studies indicated that berberine (BBR) is a potential natural drug for the treatment of various bone diseases. However, it still needs to be further studied for the treatment of osteoporosis. The current study investigated the inhibitory effects of BBR on receptor activator of nuclear factor- κ B ligand (RANKL)-induced osteoclast differentiation in vitro and in vivo. Cell-based assays were performed using osteoclasts generated in cultures of murine bone marrow-derived macrophages (BMMs) treated with RANKL and M-CSF. The effects of BBR on in vivo lipopolysaccharide (LPS)-mediated bone loss were evaluated using ICR mice. BBR significantly inhibited TRAP-positive osteoclast formation induced by RANKL. BBR also inhibited RANKL-induced Akt, p38 and ERK phosphorylation and I κ B degradation, and suppressed RANKL-induced expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1), which is a key transcription factors for osteoclast formation. BBR reduced the mRNA levels of osteoclast markers, including TRAP, osteoclast-associated receptor (OSCAR), cathepsin K, and ATPase H + transporting V0 subunit d2 (ATP6v0d2). Moreover, BBR prevented LPS-mediated bone loss in vivo. We suggest BBR as a natural compound that can be a potential therapeutic agent for osteoclast-related bone diseases.

Berberine promotes osteogenic differentiation of mesenchymal stem cells with therapeutic potential in periodontal regeneration

Periodontal disease is a bacterial infection-associated disease of the periodontal tissues characterized by the destruction of tooth-supporting structures, including alveolar bone. The ideal goal of periodontal therapy is the complete regeneration of alveolar bone in a healthy microenvironment free of infection. In this study, we found that berberine, a benzylisoquinoline plant alkaloid from Coptidis Rhizoma, strongly inhibited the growth of Porphyromonas gingivalis. Gingipain is the most important virulence factor of Porphyromonas gingivalis in the process of periodontal tissue destruction. Berberine also had an inhibitory effect on gingipain activity in a concentration dependent manner. Remarkably, berberine restored the downregulation of osteogenesis-related genes expression in bone mesenchymal stem cells (BMSCs) induced by Porphyromonas gingivalis infection, and significantly increased the expression of osteogenesis-related genes such as OSX, COLI, ALP, OCN and OPN compared to the control group. This results suggested that berberine may directly promote osteogenesis. Further in-vitro studies demonstrated that berberine statistically significantly promoted the osteogenic differentiation of BMSCs at concentrations of 1-10 μM. In the research on the mechanisms, we found that both total β-catenin and nuclear β-catenin accumulation were statistically significantly increased by berberine. And the transcriptional activity of β-catenin/TCF was about 2 folds higher than the control group. Furthermore, Wnt signalling specific inhibitor DKK-1 blocked the above effects of berberine. These demonstrated that Wnt/β-catenin signalling pathway was involved in the osteogenic differentiation induced by berberine. The antibacterial actions in combination with the promotion role in osteogenic differentiation position berberine as a prospective drug for periodontal tissue regeneration.

Features and outcomes of drugs for combination therapy as multi-targets strategy to combat Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD), a deleterious neurodegenerative disorder that impairs memory, cognitive functions and may lead to dementia in late stage of life. The pathogenic cause of AD remains incompletely understood and FDA approved drugs are partial inhibitors rather than curative. Most of drugs are synthetic or natural products as galanthamine is an alkaloid obtained from Galanthus spp. Huperzine A, an alkaloid found in Huperzia spp., gingkolides a diterpenoids from Gingko biloba and many ethnobotanicals like Withania somnifera (L.) Dunal., Physostigma venenosum Balf., Bacopa monnieri (L.) Wettst., Centella asiatica (L.) Urb. have been used by traditional Indian, Chinese, and European system of medicines in AD. Clinical significance opioid alkaloid in Papaver somniferum has shown another dimension to this study. Over exploitation of medicinal plants with limited bioactive principles has provided templates to design synthetic drugs in AD e.g. rivastigmine, phenserine, eptastigmine based on chemical structure of physostigmine of Physostigma venenosum Balf. Even ZT-1 a prodrug of Hup A and memogain a prodrug of galantamine has achieved new direction in drug development in AD. All these first-line cholinesterase-inhibitors are used as symptomatic treatments in AD. Single modality of "One-molecule-one-target" strategy for treating AD has failed and so future therapies on "Combination-drugs-multi-targets" strategy (CDMT) will need to address multiple aspects to block the progression of pathogenesis of AD. Besides, cholinergic and amyloid drugs, in this article we summarize proteinopathy-based drugs as AD therapeutics from a variety of biological sources. In this review, an attempt has been made to elucidate the molecular mode of action of various plant products, and synthetic drugs investigated in various preclinical and clinical tests in AD. It also discusses current attempts to formulate a comprehensive CDMT strategy to counter complex pathogenesis in AD.

MATERIALS AND METHODS

Information were collected from classical books on medicinal plants, pharmacopoeias and scientific databases like PubMed, Scopus, GoogleScholar, Web of Science and electronic searches were performed using Cochrane Library, Medline and EMBASE. Also published scientific literatures from Elsevier, Taylor and Francis, Springer, ACS, Wiley publishers and reports by government bodies and documentations were assessed.

RESULTS

60 no. of natural and synthetic drugs have been studied with their significant bioactivities. A decision matrix designed for evaluation of drugs for considering to the hypothetic "CDMT" strategy in AD. We have introduced the scoring pattern of individual drugs and based on scoring pattern, drugs that fall within the scoring range of 18-25 are considered in the proposed CDMT. It also highlights the importance of available natural products and in future those drugs may be considered in CDMT along with the qualified synthetic drugs.

CONCLUSION

A successful validation of the CDMT strategy may open up a debate on health care reform to explore other possibilities of combination therapy. In doing so, it should focus on clinical and molecular relationships between AD and CDMT. A better understanding of these relationships could inform and impact future development of AD-directed treatment strategies. This strategy also involves in reducing costs in treatment phases which will be affordable to a common man suffering from AD.

The promotion function of Berberine for osteogenic differentiation of human periodontal ligament stem cells via ERK-FOS pathway mediated by EGFR

Coptidis Rhizoma binds to the membrane receptors on hPDLSC/CMC, and the active ingredient Berberine (BER) that can be extracted from it may promote the proliferation and osteogenesis of periodontal ligament stem cells (hPDLSC). The membrane receptor that binds with BER on the cell surface of hPDLSC, the mechanism of direct interaction between BER and hPDLSC, and the related signal pathway are not yet clear. In this research, EGFR was screened as the affinity membrane receptor between BER and hPDLSC, through retention on CMC, competition with BER and by using a molecular docking simulation score. At the same time, the MAPK PCR Array was selected to screen the target genes that changed when hPDLSC was simulated by BER. In conclusion, BER may bind to EGFR on the cell membrane of hPDLSC so the intracellular ERK signalling pathways activate, and nuclear-related genes of FOS change, resulting in the effect of osteogenesis on PDLSC.

BCAP promotes osteoclast differentiation through regulation of the p38-dependent CREB signaling pathway

Many studies have determined that PI3K-Akt signaling pathways play important roles in osteoclast differentiation and function. In the present study, we investigated the roles of B-cell adaptor for PI3K (BCAP), which is a PI3K binding molecule, in osteoclasts. Overexpression of BCAP in osteoclast precursor cells enhanced osteoclast differentiation induced by tumor necrosis factor alpha (TNF-α) as well as receptor activator of nuclear factor-κB ligand (RANKL). Conversely, osteoclast differentiation mediated by both cytokines was attenuated when BCAP expression was downregulated using small interfering RNA. Notably, BCAP induced Akt activation only upon stimulation by RANKL, but not by TNF-α. However, BCAP activated p38-dependent cAMP response element-binding protein (CREB) phosphorylation induced by both RANKL and TNF-α. Collectively, we showed that BCAP plays an important role in osteoclast differentiation by regulating the p38-dependent CREB signaling pathway, and that BCAP might be a new therapeutic target for bone diseases.

Proinflammatory and osteolysis-inducing effects of 3D printing Ti6Al4V particles in vitro and in vivo

Ti6Al4V printing particles have been recently used for fabricating orthopedic implants. Removing these particles completely from fabricated implants is challenging. Furthermore, recycled particles are commonly used in fabrication without additional analysis. Ti6Al4V wear particles derived from orthopedic implants are known to induce inflammatory responses and osteolysis. However, the biosafety of printing particles remains unknown. Here, we investigated the proinflammatory and osteolysis-inducing effects of commonly used original and recycled Ti6Al4V printing particles in vitro and in vivo. Our results indicated that although less serious effects were induced compared to wear particles, inflammatory responses and osteoclast-mediated bone resorption were induced by the original printing particles in a particle size-dependent manner. Recycled particles were found to more strongly stimulate bone resorption and inflammatory responses than the original particles; the in vivo effect was enhanced with an increase in particle concentration. Furthermore, the results of our in vitro experiments verified that the printing particles activate macrophages to secrete inflammatory cytokines and promote osteoclastogenesis, which is closely related to particle size and concentration. Taken together, our findings provide a valuable reference for the use of raw printing materials and examination of recycling procedures for implant fabrication.

Effects of deficiency of Kelch-like ECH-associated protein 1 on skeletal organization: a mechanism for diminished nuclear factor of activated T cells cytoplasmic 1 during osteoclastogenesis

Kelch-like ECH-associated protein 1 (Keap1) binds to nuclear factor E2 p45-related factor 2 (Nrf2), a transcription factor for antioxidant enzymes, to suppress Nrf2 activation. The role of oxidative stress in many diseases supports the possibility that processes that are associated with Nrf2 activation might offer therapeutic potential. Nrf2 deficiency induces osteoclastogenesis, which is responsible for bone loss, by activating receptor activator of NF-κB ligand (RANKL)-mediated signaling; however, the effects of Keap1 deficiency remain unclear. By using Keap1-deficient newborn mice, we observed that talus and calcaneus bone formation was partially retarded and that osteoclast number was reduced in vivo without severe gross abnormalities. In addition, Keap1-deficient macrophages were unable to differentiate into osteoclasts in vitrovia attenuation of RANKL-mediated signaling and expression of nuclear factor of activated T cells cytoplasmic 1 (NFATc1), a key transcription factor that is involved in osteoclastogenesis. Furthermore, Keap1 deficiency up-regulated the expression of Mafb, a negative regulator of NFATc1. RANKL-induced mitochondrial gene expression is required for down-regulation of IFN regulatory factor 8 (IRF-8), a negative transcriptional regulator of NFATc1. Our results indicate that Keap1 deficiency down-regulated peroxisome proliferator-activated receptor-γ coactivator 1β and mitochondrial gene expression and up-regulated Irf8 expression. These results suggest that the Keap1/Nrf2 axis plays a critical role in NFATc1 expression and osteoclastogenic progression.-Sakai, E., Morita, M., Ohuchi, M., Kido, M. A., Fukuma, Y., Nishishita, K., Okamoto, K., Itoh, K., Yamamoto, M., Tsukuba, T. Effects of deficiency of Kelch-like ECH-associated protein 1 on skeletal organization: a mechanism for diminished nuclear factor of activated T cells cytoplasmic 1 during osteoclastogenesis.

Beneficial Effects of Berberine on Oxidized LDL-Induced Cytotoxicity to Human Retinal Müller Cells

Purpose

Limited mechanistic understanding of diabetic retinopathy (DR) has hindered therapeutic advances. Berberine, an isoquinolone alkaloid, has shown favorable effects on glucose and lipid metabolism in animal and human studies, but effects on DR are unknown. We previously demonstrated intraretinal extravasation and modification of LDL in human diabetes, and toxicity of modified LDL to human retinal Müller cells. We now explore pathogenic effects of modified LDL on Müller cells, and the efficacy of berberine in mitigating this cytotoxicity.

Methods

Confluent human Müller cells were exposed to in vitro–modified ‘highly oxidized, glycated (HOG-) LDL versus native-LDL (N-LDL; 200 mg protein/L) for 6 or 24 hours, with/without pretreatment with berberine (5 μM, 1 hour) and/or the adenosine monophosphate (AMP)-activated protein kinase (AMPK) inhibitor, Compound C (5 μM, 1 hour). Using techniques including Western blots, reactive oxygen species (ROS) detection assay, and quantitative real-time PCR, the following outcomes were assessed: cell viability (CCK-8 assay), autophagy (LC3, Beclin-1, ATG-5), apoptosis (cleaved caspase 3, cleaved poly-ADP ribose polymerase), oxidative stress (ROS, nuclear factor erythroid 2-related factor 2, glutathione peroxidase 1, NADPH oxidase 4), angiogenesis (VEGF, pigment epithelium-derived factor), inflammation (inducible nitric oxide synthase, intercellular adhesion molecule 1, IL-6, IL-8, TNF-α), and glial cell activation (glial fibrillary acidic protein).

Results

Native-LDL had no effect on cultured human Müller cells, but HOG-LDL exhibited marked toxicity, significantly decreasing viability and inducing autophagy, apoptosis, oxidative stress, expression of angiogenic factors, inflammation, and glial cell activation. Berberine attenuated all the effects of HOG-LDL (all P < 0.05), and its effects were mitigated by AMPK inhibition (P < 0.05).

Conclusions

Berberine inhibits modified LDL-induced Müller cell injury by activating the AMPK pathway, and merits further study as an agent for preventing and/or treating DR.

Regulation of Osteoclast Growth and Fusion by mTOR/raptor and mTOR/rictor/Akt

Osteoclasts are giant bone cells formed by fusion from monocytes and uniquely capable of a complete destruction of mineralized tissues. Previously, we have demonstrated that in energy-rich environment not only osteoclast fusion index (the number of nuclei each osteoclast contains), but also cytoplasm volume per single nucleus was increased. The goal of this study was to investigate the regulation of metabolic sensor mTOR during osteoclast differentiation in energy-rich environment simulated by addition of pyruvate. We have found that in the presence of pyruvate, the proportion of mTOR associated with raptor increased, while mTOR-rictor-mediated Akt phosphorylation decreased. Inhibition of mTOR with rapamycin (10 nM) significantly interfered with all aspects of osteoclastogenesis. However, rapamycin at 1 nM, which preferentially targets mTOR-raptor complex, was only effective in control cultures, while in the presence of pyruvate osteoclast fusion index was successfully increased. Inhibition of Akt drastically reduced osteoclast fusion, however in energy-rich environment, osteoclasts of comparable size were formed through increased cytoplasm growth. These data suggest that mTOR-rictor mediated Akt signaling regulates osteoclast fusion, while mTOR-raptor regulation of protein translation contributes to fusion-independent cytoplasm growth. We demonstrate that depending on the bioenergetics microenvironment osteoclastogenesis can adjust to occur through preferential multinucleation or through cell growth, implying that attaining large cell size is part of the osteoclast differentiation program.

Sialoglycoproteins prepared from the eggs of Carassius auratus prevent bone loss by inhibiting the NF-κB pathway in ovariectomized rats

In this study, we investigated the improvement of osteoporosis by sialoglycoproteins isolated from the eggs of Carassius auratus (Ca-SGP) in ovariectomized rats. Ca-SGP was supplemented to ovariectomized Sprague-Dawley rats for 90 days. The results showed that Ca-SGP treatment remarkably prevented the reduction of bone mass, improved cancellous bone structure and biochemical properties. Ca-SGP also significantly decreased the serum contents of TRAP, Cath-K, MMP-9, DPD, CTX-1, Ca, and P. Mechanism investigation revealed that Ca-SGP significantly increased the OPG/RANKL ratio in mRNA expression, protein expression and serum content. Further research suggested that NF-κB signaling pathways were inhibited by suppressing the mRNA and protein expressions of NFATc1 and TRAF6, diminishing the mRNA expression and phosphorylation of NF-κB p65, three key transcription factors in NF-κB pathways. These results suggest that Ca-SGP can improve osteoporosis by inhibiting bone resorption via suppressing the activation of osteoclastogenesis related NF-κB pathways.