Tatarinan O, a lignin-like compound from the roots of Acorus tatarinowii Schott inhibits osteoclast differentiation through suppressing the expression of c-Fos and NFATc1

Acorus tatarinowii Schott: A Review of Its Botany, Traditional Uses, Phytochemistry, and Pharmacology

Acorus tatarinowii Schott (A. tatarinowii) is a natural medicinal plant. It plays an indispensable role in the treatment of diseases by the empirical medicine system and has achieved remarkable curative effects. A. tatarinowii is often used to treat various diseases, such as depression, epilepsy, fever, dizziness, heartache, stomachache, etc. More than 160 compounds of different structural types have been identified in A. tatarinowii, including phenylpropanoids, terpenoids, lignans, flavonoids, alkaloids, amides, and organic acids. These bioactive ingredients make A. tatarinowii remarkable for its pharmacological effects, including antidepressant, antiepileptic, anticonvulsant, antianxiety, neuroprotective, antifatigue, and antifungal effects, improving Alzheimer's disease, and so on. It is noteworthy that A. tatarinowii has been widely used in the treatment of brain diseases and nervous system diseases and has achieved satisfactory therapeutic effects. This review focused on the research publications of A. tatarinowii and aimed to summarize the advances in the botany, traditional uses, phytochemistry, and pharmacology, which will provide a reference for further studies and applications of A. tatarinowii.

Acorus calamus var. angustatus Besser: Insight into current research on ethnopharmacological use, phytochemistry, pharmacology, toxicology, and pharmacokinetics

A. calamus var. angustatus Besser is an important traditional medicinal herb commonly used in China and other Asian countries. This study is the first systematic review of the literature to thoroughly analyze the ethnopharmacological application, phytochemistry, pharmacology, toxicology and pharmacokinetic properties of A. calamus var. angustatus Besser and provides a rationale for future research and prospects for application in clinical treatment. Information on relevant studies investigating A. calamus var. angustatus Besser was collected from SciFinder, the Web of Science, PubMed, CNKI, Elsevier, ResearchGate, ACS, Flora of China, and Baidu Scholar, etc. up to December 2022. In addition, information was also obtained from Pharmacopeias, books on Chinese herbal classics, local books, as well as PhD and MS dissertations. A. calamus var. angustatus Besser has played an important role in the herbal treatment of coma, convulsion, amnesia, and dementia for thousands of years. Studies investigating the chemical constituents of A. calamus var. angustatus Besser have isolated and identified 234 small-molecule compounds and a few polysaccharides. Among them, simple phenylpropanoids represented by asarone analogues and lignans are the two main active ingredients, which can be considered characteristic chemotaxonomic markers of this herb. In vitro and in vivo pharmacological studies indicated that crude extracts and active compounds from A. calamus var. angustatus Besser display a wide range of pharmacological activities, especially as treatment for Alzheimer's disease (AD), and anticonvulsant, antidepressant-like, anxiolytic-like, anti-fatigue, anti-Parkinson, neuroprotection, and brain protection properties, providing more evidence to explain the traditional medicinal uses and ethnopharmacology. The clinical therapeutic dose of A. calamus var. angustatus Besser does not present any toxic effects, but its main active ingredients α-asarone and β-asarone at excessive dose may lead to toxicity, and in particular, their respective epoxide metabolites may exert potential toxicity to the liver. This review provides a reference and further information for the future development and clinical application of A. calamus var. angustatus Besser.

Sustainable lignin and lignin-derived compounds as potential therapeutic agents for degenerative orthopaedic diseases: A systemic review

Lignin, the most abundant natural and sustainable phenolic compound in biomass, has exhibited medicinal values due to its biological activities decided by physicochemical properties. Recently, the lignin and its derivatives (such as lignosulfonates and lignosulfonate) have been proven efficient in regulating cellular process and the extracellular microenvironment, which has been regarded as the key factor in disease progression. In orthopaedic diseases, especially the degenerative diseases represented by osteoarthritis and osteoporosis, excessive activated inflammation has been proven as a key stage in the pathological process. Due to the excellent biocompatibility, antibacterial and antioxidative activities of lignin and its derivatives, they have been applied to stimulate cells and restore the uncoupling bone remodeling in the degenerative orthopaedic diseases. However, there is a lack of a systemic review to state the current research actuality of lignin and lignin-derived compounds in treating degenerative orthopaedic diseases. Herein, we summarized the current application of lignin and lignin-derived compounds in orthopaedic diseases and proposed their possible therapeutic mechanism in treating degenerative orthopaedic diseases. It is hoped this work could guide the future preparation of lignin/lignin-derived drugs and implants as available therapeutic strategies for clinically degenerative orthopaedic diseases.

Porphyromonas gingivalis Induces Bisphosphonate-Related Osteonecrosis of the Femur in Mice

One of the most prominent characteristics of bisphosphonate-related osteonecrosis of the jaw(BRONJ) is its site-specificity. Osteonecrosis tends to occur specifically in maxillofacial bones, in spite of a systemic administration of the medicine. Previous studies suggested rich blood supply and fast bone turnover might be reasons for BRONJ. Yet, a sound scientific basis explaining its occurrence is still lacking. The present study aimed to explore the role of Porphyromonas gingivalis (P. gingivalis), an important oral pathogen, on the site-specificity of bisphosphonate-induced osteonecrosis and to elucidate its underlying mechanism. Mice were intraperitoneally injected with zoledronic acid (ZA) or saline for 3 weeks. In the third week, the right mandibular first molars were extracted and circular bone defects with a diameter of 1 mm were created in right femurs. After the operation, drug administration was continued, and P. gingivalis suspension was applied to the oral cavities and femur defects. The mice were killed after four or eight weeks postoperatively. The right mandibles and femurs were harvested for micro-CT and histological analyses. A poor healing of bone defects of both jaws and femurs was noted in mice injected with both ZA and P. gingivalis. Micro-CT analysis showed a decreased bone volume, and histological staining showed an increased number of empty osteocyte lacunae, a decreased collagen regeneration, an increased inflammatory infiltration and a decreased number of osteoclasts. In addition, the left femurs were collected for isolation of osteoclast precursors (OCPs). The osteoclastogenesis potential of OCPs was analyzed in vitro. OCPs extracted from mice of ZA-treated groups were shown to have a lower osteoclast differentiation potential and the expression level of related genes and proteins was declined. In conclusion, we established a mouse model of bisphosphonate-related osteonecrosis of both the jaw and femur. P. gingivalis could inhibit the healing of femur defects under the administration of ZA. These findings suggest that P. gingivalis in the oral cavity might be one of the steering compounds for BRONJ to occur.

α-Asarone Attenuates Osteoclastogenesis and Prevents Against Oestrogen-Deficiency Induced Osteoporosis

Osteoporosis (OP) is defined as low bone mineral density which features over activated osteoclasts (OCs) and bone resorption. Targeting excessive OCs activity is thought to be an effective therapeutic approach for OP treatment. α-asarone (ASA), a compound from the traditional Chinese medicinal herb Acorus tatarinowii, has been widely used as a therapeutic agent against several diseases such as epilepsy, cough, bronchitis and asthma for many years. Recently, it was reported that ASA-derived lignins which were purified from Acorus tatarinowii root tissues effectively suppressed both RANKL-induced osteoclastogenesis and bone resorption. Besides, a classic Chinese formulation Bajitianwan (BJTW) which consisted of root and rhizome of Acorus tatarinowii Schott also showed positive effects on age-related bone loss. In the present study, we aimed to study the effects of ASA on osteoclastogenesis in vitro and in vivo. As illustrated by TRAP staining, ASA was capable of inhibiting RANKL-induced osteoclastogenesis in a dose-dependent manner, not only at an early-stage, but also in the late-stage. Besides, it also effectively suppressed bone resorption of mature OCs in a pit resorption assay. The formation of F-actin ring during osteoclastogenesis, which was important in OCs bone-resorption, was impaired as well. Subsequent mechanism experiments exposed that ASA inhibited osteoclastogenesis related genes in a time-dependent manner through AKT, p38 and NF-κB, followed by NFATc1/c-fos signaling pathway. Notably, our in vivo study uncovered that ASA was capable of improving the bone microstructure in oestrogen-deficiency induced OP models. Thus, our current work highlighted the important role of an old drug ASA in bone metabolism especially in OCs differentiation. ASA may find its potential as a lead compound to treat excessive OCs activity-induced bone loss diseases and more structure optimization is further needed.

Effects and Mechanisms of Rhus chinensis Mill. Fruits on Suppressing RANKL-Induced Osteoclastogenesis by Network Pharmacology and Validation in RAW264.7 Cells

Rhus chinensis Mill. fruits are a kind of widely distributed edible seasoning, which have been documented to possess a variety of biological activities. However, its inhibitory effect on osteoclast formation has not been determined. The objective of this study was to evaluate the effect of the fruits on osteoclast differentiation of RAW264.7 cells, induced by receptor activator of nuclear factor-κB ligand (RANKL) and to illuminate the potential mechanisms using network pharmacology and western blots. Results showed that the extract containing two organic acids and twelve phenolic substances could effectively inhibit osteoclast differentiation in RANKL-induced RAW264.7 cells. Network pharmacology examination and western blot investigation showed that the concentrate essentially decreased the expression levels of osteoclast-specific proteins, chiefly through nuclear factor kappa-B, protein kinase B, and mitogen-activated protein kinase signaling pathways, particularly protein kinase B α and mitogen-activated protein kinase 1 targets. Moreover, the extract likewise directly down regulated the expression of cellular oncogene Fos and nuclear factor of activated T-cells cytoplasmic 1 proteins. Citric acid, quercetin, myricetin-3-O-galactoside, and quercetin-3-O-rhamnoside were considered as the predominant bioactive ingredients. Results of this work may provide a scientific basis for the development and utilization of R. chinensis fruits as a natural edible material to prevent and/or alleviate osteoporosis-related diseases.

Phospholipase Cγ Signaling in Bone Marrow Stem Cell and Relevant Natural Compounds Therapy

Excessive bone resorption has been recognized play a major role in the development of bone-related diseases such as osteoporosis, rheumatoid arthritis, Paget's disease of bone, and cancer. Phospholipase Cγ (PLCγ) family members PLCγ1 and PLCγ2 are critical regulators of signaling pathways downstream of growth factor receptors, integrins, and immune complexes and play a crucial role in osteoclast. Ca2+ signaling has been recognized as an essential pathway to the differentiation of osteoclasts. With growing attention and research about natural occurring compounds, the therapeutic use of natural active plant-derived products has been widely recognized in recent years. In this review, we summarized the recent research on PLCγ signaling in bone marrow stem cells and the use of several natural compounds that were proven to inhibit RANKL-mediated osteoclastogenesis via modulating PLCγ signaling pathways.

ASP2-1, a polysaccharide from Acorus tatarinowii Schott, inhibits osteoclastogenesis via modulation of NFATc1 and attenuates LPS-induced bone loss in mice

Spectroscopic analysis of HPLC-purified 7.3-kD Acorus tatarinowii Schott root polysaccharide ASP2-1 (FT-IR, NMR) revealed respective monosaccharide proportions of glucose: galactose: arabinose: xylose: galacturonic acid: mannose: rhamnose: glucuronic acid:fucose of 49.1:16.0:11.6:10.2:5.3:2.9:2.2:1.7:0.8. In vitro, ASP2-1 inhibited osteoclastogenesis-associated bone resorption, RANKL-induced osteoclastogenesis and F-actin ring formation and suppressed osteoclastogenesis-associated gene expression (e.g., TRAP, OSCAR, Atp6v0d2, αV, β3, MMP9 and CtsK) as shown via RT-PCR. ASP2-1-treated RANKL-stimulated bone marrow-derived macrophages exhibited decreased levels of NFATc1 and c-Fos mRNAs and corresponding transcription factor proteins, elevated expression of negative NFATc1 regulators (Mafb, IRF8, Bcl6) and reduced their upstream negative regulator (Blimp1) expression. ASP2-1 inhibition of NFATc1 expression involved PLCγ2-Ca²⁺ oscillation-calcineurin axis suppression, reflecting suppression of RANKL-induced PLCγ2 activation (and associated Ca²⁺ oscillation) and calcineurin catalytic subunit PP2BAα expression without inhibiting NF-κB and MAPKs activation or phosphorylation. Staining (H&E, TRAP) and micro-CT assays revealed ASP2-1 attenuated bone destruction and osteoclast over-activation and improved tibia micro-architecture in a murine LPS-induced bone loss model. Thus, ASP2-1 may alleviate inflammatory bone loss-associated diseases.

Targeting autophagy by natural product Ursolic acid for prevention and treatment of osteoporosis

With the growth of the aging population, osteoporosis is becoming a global health problem. Ursolic acid (UA) is an active ingredient existed in a variety of foods and nature plants and owns plenty of pharmacological effects especially in treating metabolic disease. Our predication from network pharmacology hinted that UA has potential for ameliorating osteoporosis. Firstly through in vivo experiment, we confirmed that UA administration obviously protected against ovariectomy (OVX)-induced osteoporosis in rats by improving microarchitectural deterioration of trabecular bone (P < 0.001), decreasing numbers of TRAP positive osteoclast in vertebra (P < 0.001), as well as decreasing serum osteoclast-specific cytokines release (P < 0.001). Besides, UA ameliorated kidney damage secondary to OVX-induced osteoporosis by ameliorating glomerular atrophy, decreasing BUN and creatinine levels in OVX rats. In vitro, UA noticeably decreased osteoclastic-special marker proteins c-Fos and NFATc1 expressions (P < 0.001) in response to RANKL stimulation in macrophagy. Importantly, autophagy pathway was activated in the process of osteoclast differentiation and blocked by UA pretreatment. Furthermore, autophagy inhibitors suppressed osteoclast differentiation (P < 0.001). Collectively, UA may ameliorate osteoporosis by suppressing osteoclast differentiation mediated by autophagy. Our research provides scientific support for UA treating osteoporosis and offers an optimal dose for daily intake of UA safely to prevent bone diseases.

Bajitianwan attenuates D-galactose-induced memory impairment and bone loss through suppression of oxidative stress in aging rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoporosis and Alzheimer's disease (AD) are both senile diseases, which are closely related to oxidative stress. Bajitianwan (BJTW) is a classic Chinese formulation consisting of seven herbal drugs: the root of Morinda officinalis F.C.How., root and rhizome of Acorus tatarinowii Schott, the root bark of Lycium chinense Mill., the sclerotium of Poria cocos (Schw.) Wolf, the root of Polygala tenuifolia Willd., sclerotium with host wood of Poria cocos (Schw.) Wolf and root and rhizome of Panax ginseng C. A. Mey. BJTW has been used for the treatment of osteoporosis and AD for hundreds of years.

AIM OF THE STUDY

This study aimed to investigate the protective effects of BJTW in the amelioration of memory impairment and bone loss induced by D-galactose and to explore the underlying mechanism.

MATERIALS AND METHODS

The aging model was established in male Wistar rats by subcutaneous injection of D-galactose (100 mg/kg), and the rats were treated with huperzine-A, alendronate sodium, or the aqueous extract of BJTW for 4 months. Cognitive performance was evaluated with the Morris water maze. Rat femurs were scanned using microcomputed tomography to obtain three-dimensional imagery of bone microstructure. The impact of D-galactose on the expression of Forkhead box O1 and superoxide dismutase 2 in femur tissue was also evaluated.

RESULTS

For the model group, BJTW treatment significantly reduced the latency time for finding the target platform in the directional swimming test and increased time spent swimming in the target quadrant with the probe test. Additionally, BJTW treatment alleviated D-galactose-induced bone loss through regulation of levels of alkaline phosphatase, osteocalcin, osteoprotegerin, and receptor activator of nuclear factor kappa B ligand. Furthermore, BJTW treatment increased catalase and glutathione peroxidase levels in serum, reduced malondialdehyde content in hippocampus, and upregulated expression of Forkhead O1, which upregulated superoxide dismutase 2 in the femur.

CONCLUSIONS

BJTW had positive effects on age-related memory impairments and bone loss. It may be a promising antioxidant candidate for treatment of Alzheimer's disease and osteoporosis.

Anemonin Attenuates RANKL-Induced Osteoclastogenesis and Ameliorates LPS-Induced Inflammatory Bone Loss in Mice via Modulation of NFATc1

Osteoporosis is a metabolic bone disease characterized by insufficient osteoblastic function and/or excessive osteoclastic activity. One promising strategy for treating osteoporosis is inhibiting excessive osteoclast resorbing activity. Previous studies have revealed that anemonin (ANE), isolated from various types of Chinese natural herbs, has anti-inflammatory and anti-oxidative properties. However, whether ANE regulates osteoclastogenesis is unknown. This study aimed to investigate the potential effect of ANE on osteoclastogenesis and inflammatory bone loss in mice. In in vitro studies, ANE suppressed RANKL-stimulated osteoclast differentiation and function by downregulating the expression of osteoclast master transcriptor NFATc1, as well as its upstream transcriptor c-Fos, by decreasing NF-κB and ERK1/2 signaling. Interestingly, ANE did not change the phosphorylation and degradation of IκB-α and activation of JNK and p38 MAPKs. However, ANE repressed the phosphorylation of MSK-1 which is the downstream target of ERK1/2 and p38 MAPK and can phosphorylate NF-κB p65 subunit. These results implicated that ANE might suppress NF-κB activity via modulation of ERK1/2 mediated NF-κB phosphorylation. In addition, ANE directly suppressed NFATc1 transcription by inhibiting Blimp-1 expression, and the subsequent enhancement of the expression of NFATc1 negative regulators, Bcl-6 and IRF-8. Moreover, in vivo studies were conducted using an LPS-induced inflammatory bone loss mice model. Micro-CT and histology analysis showed that ANE treatment significantly improved trabecular bone parameters and bone destruction. These data indicate that ANE can attenuate RANKL-induced osteoclastogenesis and ameliorate LPS-induced inflammatory bone loss in mice through modulation of NFATc1 via ERK1/2-mediated NF-κB phosphorylation and Blimp1 signal pathways. ANE may provide new treatment options for osteoclast-related diseases.

Tatarinan T, an α-asarone-derived lignin, attenuates osteoclastogenesis induced by RANKL via the inhibition of NFATc1/c-Fos expression

We have previously reported that the lignin-like compounds, Tatarinan O (TO) and Tatarinan N (TN), extracted from the roots of Acorus tatarinowii Schott, inhibit receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis. In the present study, the potential function of the α-asarone-derived lignins, Tatarinan T (TT) and Tatarinan A (TA), to regulate RANKL-induced osteoclastogenesis was investigated, and it was found that only early treatment with TT may inhibit RANKL-triggered formation of osteoclasts and resorption. The results revealed repressed expression levels of several osteoclast marker genes, including ATPase H⁺ -transporting V0 subunit d2 (Atp6v0d2), αvβ3 integrin, and osteoclast-associated receptor (OSCAR), following TT treatment during osteoclastogenesis. Moreover, TT reduced the expression levels of the core transcription elements, nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) and c-Fos. However, western blotting analysis showed that TT treatment did not alter nuclear factor-κΒ (NF-κB) activation or mitogen-activated protein kinase (MAPK) or Syk/Btk/phospholipase Cγ2 (PLCγ2) phosphorylation. Taken together, these results suggest the potential of TT in the treatment of diseases of increased bone resorption.

Zoledronic acid inhibits osteoclast differentiation and function through the regulation of NF-κB and JNK signalling pathways

It is well known that extensive osteoclast formation plays a key role in osteoporosis in post‑menopausal women and the elderly. The suppression of extensive osteoclastogenesis and bone resorption may be an effective preventive strategy for osteoporosis. Zoledronic acid (ZOL) has been indicated to play an essential role in regulating bone mineral density and has already been used in large clinical trials. However, the effects of ZOL on osteoclastogenesis remain to be fully elucidated. Therefore, the present study aimed to determine the effects of ZOL on osteoclastogenesis, and to explore the corresponding signalling pathways. By using a cell viability assay, as well as in vitro osteoclastogenesis, immunofluorescence and resorption pit assays, we demonstrated that ZOL (0.1‑5 µM) suppressed receptor activator of nuclear factor‑κB ligand (RANKL)‑induced osteoclast differentiation and bone resorptive activity. Furthermore, western blot analysis and reverse transcription‑quantitative PCR indicated that ZOL inhibited the RANKL‑induced activation of NF‑κB and the phosphorylation of JNK in RAW264.7 cells, and subsequently decreased the expression of osteoclastogenesis‑associated genes, including calcitonin receptor, tartrate‑resistant acid phosphatase and dendritic cell‑specific transmembrane protein. ZOL inhibited osteoclast formation and resorption in vitro by specifically suppressing NF‑κB and JNK signalling. On the whole, the findings of this study indicate that ZOL may serve as a potential agent for the treatment of osteoclast‑associated diseases, including osteoporosis.

Tatarinan N inhibits osteoclast differentiation through attenuating NF-κB, MAPKs and Ca2+-dependent signaling

Osteoclasts are multinucleated cells that originate from hemopoietic stem cells. Targeting over activated osteoclasts is thought to be an effective therapeutic approach to osteoporosis. In a previous study, we reported that Tatarinan O, a lignin-like compound, suppressed RANKL-induced osteoclastogenesis. In this study, we further examined the effects on osteoclast formation of three lignin-like compounds including Tatarinan N (TN), Tatarinan U (TU) and Tatarinan V (TV), all containing a common structure of asarone. We found that only TN suppressed RANKL-induced osteoclast differentiation, bone resorption pit formation and F-acting ring formation. TU and TV did not influence RANKL-induced osteoclastogenesis. We also found that TN dose-dependently inhibited the expression of osteoclastogenesis-associated genes, including TRAP, cathepsin K and MMP-9. Furthermore, we found that TN down-regulated the key transcription factor NFATc1 and c-Fos by preventing the activation of NF-κB and phosphorylation of MAPKs including ERK1/2 and p38 but not JNK. TN attenuated calcineurin expression via suppression of the Btk-PLCγ2 cascade and reduction of intracellular Ca²⁺, modulating NFATc1 activation. Taking together, our results indicated that TN might have therapeutic potential for osteoporosis.

Vγ9Vδ2 T cells inhibit immature dendritic cell transdifferentiation into osteoclasts through downregulation of RANK, c‑Fos and ATP6V0D2

Osteoimmunological studies have revealed that T cells exert a powerful impact on the formation and activity of osteoclasts and bone remodeling. Evidence demonstrates that immature dendritic cells (iDCs) are more efficient transdifferentiating into osteoclasts (OCs) than monocytes. However, whether Vγ9Vδ2 T (γδ T) cells stimulate or inhibit iDC transdifferentiation into OCs has never been reported. The aim of the present study was to investigate the effects of γδ T cells on this transdifferentiation process. γδ T cells and iDCs were isolated from the peripheral blood of healthy volunteers separately and were co-cultured with Transwelll inserts, with γδ T cells in the upper chamber and iDCs in the lower chamber. IDCs were treated with macrophage-colony stimulating factor and receptor activator of nuclear factor-κB (RANK) ligand. Tartrate resistant acid phosphatase (TRAP) assay and dentine resorption assay were performed to detect OC formation and their resorption capacity, respectively. The mRNA expression of OCs was examined using a micro-array and real time-quantitative polymerase chain reaction to trace the changes during iDC transdifferentiation into OCs. The results demonstrated that γδ T cells significantly inhibited the generation of the TRAP-positive OCs from iDCs and their resorption capacity. The microarray analysis identified decreased expression level of Fos proto-oncogene AP-1 transcription factor subunit (c-Fos), ATPase H⁺ transporting V0 subunit d (ATP6V0D2) and cathepsin K when iDCs were co-cultured with γδ T cells. These genes are associated with OC differentiation, indicating that γδ T cells suppressed iDCs osteoclastogenesis by downregulation of the RANK/c-Fos/ATP6V0D2 signaling pathway. The present findings provide novel insights into the interactions between human γδ T cells and iDCs, and demonstrate that γδ T cells are capable of inhibiting OC formation and their activity via downregulation of genes associated with OC differentiation.

Tatanan A from the Acorus calamus L. root inhibited dengue virus proliferation and infections

BACKGROUND

Acorus calamus l. (Acoraceae) is a well-known traditional Chinese medicinal plant, whose root are historically mainly used to treat neurodegenerative diseases, and for cholera treatment. This datum strongly indicates the antimicrobial activity of A. calamus.

PURPOSE

Our goal is to find the active constituents of A. calamus to treat dengue virus (DENV) infections, and to study the effects and mechanisms of these active substances.

METHODS

The root of A. calamus was extracted by ethanol. Mosquito larva C6/36 cells were used for DENV2 replication and transfection host. Mouse kidney fibroblast cells (BHK-21) were used as a host cell to study the infection ability of the virus. DENV2-induced cytopathic effect (CPE) and plaque assay were used to evaluate the inhibitory effect of A. calamus extracts on DENV2 infectivity inhibition. The levels of E and NS1 protein expression were measured by real-time PCR and western blot assays.

RESULTS

12 compounds were isolated from ethanol extract of A. calamus root, tatanan A showed the best anti-DENV ability among these 12 compounds, which significantly alleviated DENV2-induced CPE and cytotoxicity effects, with an EC₅₀ of 3.9 µM. In addition, RNA replication assay further confirmed the antivirus ability of tatanan A. Time-addition assay showed that tatanan A affected the early stage of viral RNA replication, which in turn inhibited mRNA and protein levels of DENV2.

CONCLUSIONS

These results demonstrated the anti-DENV2 effect of tatanan A, in inhibiting DENV2 RNA replication and infections. In summary, tatanan A was found to be a novel natural DENV inhibitor and a potential candidate for the treatment of DENV infectious disease.

Platelet-rich plasma inhibits RANKL-induced osteoclast differentiation through activation of Wnt pathway during bone remodeling

Platelet-rich plasma (PRP) is used in the clinic as an autologous blood product to stimulate bone regeneration and chondrogenesis. Numerous studies have demonstrated that PRP affects bone remodeling by accelerating osteoblast formation. With the research perspective focusing on osteoclasts, the present study established a mouse model of mandibular advancement to examine the effect of PRP on osteoclast differentiation induced by modification of the dynamics of the temporomandibular joint (TMJ). The lower incisors of the mice were trimmed by 1 mm and the resultant change in mandibular position during the process of eating induced condylar adaptation to this change. PRP significantly increased the bone mass and decreased osteoclastic activity, in vitro as well as in vivo. Mechanistically, the reduced expression of receptor activator of nuclear factor-κB ligand (RANKL)-induced differentiation marker genes, including nuclear factor of activated T-cells, cytoplasmic 1, c-fos and tartrate-resistant acid phosphatase, and that of the resorptive activity marker genes such as cathepsin k, carbonic anhydrase 2 and matrix metalloproteinase 9, indicated that PRP suppresses RANKL-induced osteoclast differentiation. A microarray analysis revealed that several genes associated with the Wnt pathway were differentially expressed, which indicated the involvement of this pathway in osteoclast differentiation. Furthermore, the activation of the Wnt pathway was verified by reverse transcription-quantitative polymerase chain reaction and immunoblot analysis of Dickkopf-related protein 1 and β-catenin. The results of the present study indicated that PRP inhibits osteoclast differentiation through activation of the Wnt pathway.