Jolkinolide B inhibits RANKL-induced osteoclastogenesis by suppressing the activation NF-κB and MAPK signaling pathways

Sirtuins in intervertebral disc degeneration: current understanding

BACKGROUND

Intervertebral disc degeneration (IVDD) is one of the etiologic factors of degenerative spinal diseases, which can lead to a variety of pathological spinal conditions such as disc herniation, spinal stenosis, and scoliosis. IVDD is a leading cause of lower back pain, the prevalence of which increases with age. Recently, Sirtuins/SIRTs and their related activators have received attention for their activity in the treatment of IVDD. In this paper, a comprehensive systematic review of the literature on the role of SIRTs and their activators on IVDD in recent years is presented. The molecular pathways involved in the regulation of IVDD by SIRTs are summarized, and the effects of SIRTs on senescence, inflammatory responses, oxidative stress, and mitochondrial dysfunction in myeloid cells are discussed with a view to suggesting possible solutions for the current treatment of IVDD.

PURPOSE

This paper focuses on the molecular mechanisms by which SIRTs and their activators act on IVDD.

METHODS

A literature search was conducted in Pubmed and Web of Science databases over a 13-year period from 2011 to 2024 for the terms "SIRT", "Sirtuin", "IVDD", "IDD", "IVD", "NP", "Intervertebral disc degeneration", "Intervertebral disc" and "Nucleus pulposus".

RESULTS

According to the results, SIRTs and a large number of activators showed positive effects against IVDD.SIRTs modulate autophagy, myeloid apoptosis, oxidative stress and extracellular matrix degradation. In addition, they attenuate inflammatory factor-induced disc damage and maintain homeostasis during disc degeneration. Several clinical studies have reported the protective effects of some SIRTs activators (e.g., resveratrol, melatonin, honokiol, and 1,4-dihydropyridine) against IVDD.

CONCLUSION

The fact that SIRTs and their activators play a hundred different roles in IVDD helps to better understand their potential to develop further treatments for IVDD.

NOVELTY

This review summarizes current information on the mechanisms of action of SIRTs in IVDD and the challenges and limitations of translating their basic research into therapy.

Regulatory Effects of Quercetin on Bone Homeostasis: Research Updates and Future Perspectives

The imbalance of bone homeostasis has become a major public medical problem amid the background of an aging population, which is closely related to the occurrence of osteoporosis, osteoarthritis, and fractures. Presently, most drugs used in the clinical treatment of bone homeostasis imbalance are bisphosphonates, calcitonin, estrogen receptor modulators, and biological agents that inhibit bone resorption or parathyroid hormone analogs that promote bone formation. However, there are many adverse reactions. Therefore, it is necessary to explore potential drugs. Quercetin, as a flavonol compound with various biological activities, is widely distributed in plants. Studies have found that quercetin can regulate bone homeostasis through multiple pathways and targets. An in-depth exploration of the pharmacological mechanism of quercetin is of great significance for the development of new drugs. This review discusses the therapeutic mechanisms of quercetin on bone homeostasis, such as regulating the expression of long non-coding RNA, signaling pathways of bone metabolism, various types of programmed cell death, bone nutrients supply pathways, anti-oxidative stress, anti-inflammation, and activation of Sirtuins. We also summarize recent progress in improving quercetin bioavailability and propose some issues worth paying attention to, which may help guide future research efforts.

Jolkinolide B: A comprehensive review of its physicochemical properties, analytical methods, synthesis and pharmacological activity

Jolkinolide B is a typical ent-abietane-type diterpenoid, which is first found in Euphorbia jolkini. It is one of the most important active components in many toxic Euphorbia plants. In recent years, jolkinolide B has garnered increasing attention due to its high potent and multiple pharmacological activities. In order to better understand the research status of jolkinolide B, relevant information about jolkinolide B was collected from scientific databases (SciFinder Scholar, PubMed, ACS website, Elsevier, Web of Science, Google Scholar, Science Direct, and CNKI). There are few studies on chemical synthesis and biosynthesis of jolkinolide B. In addition, researchers on the activities of jolkinolide B are mostly concentrated at the cellular level, and there is a lack of research on the mechanism. In this review, the possible applications of jolkinolide B were systematically illustrated for the first time, from plant sources, physicochemical properties, analytical methods, synthesis and pharmacological activities. Jolkinolide B exhibits extensive pharmacological properties, including anticancer, anti-inflammatory, anti-osteoporosis, and anti-tuberculosis activities. Pharmacological activities of jolkinolide B were mainly focused on anticancer and anti-inflammatory activities, and the mechanism of action may be related with inhibition of JAK/STAT pathway, NF-κB pathway and PI3K/Akt/mTOR pathway. In addition, the extraction methods and analytical methods discussed in this review, will facilitate the development of novel herbal products for better healthcare solutions.

12-Deoxyphorbol-13-Hexadecanoate Abrogates OVX-Induced Bone Loss in Mice and Osteoclastogenesis via Inhibiting ROS Level and Regulating RANKL-Mediated NFATc1 Activation

Osteoporosis is a major health problem in the elderly. Almost every bone can fracture due to the increased bone fragility in osteoporosis, posing a major challenge to public health. 12-Deoxyphorbol-13-hexadecanoate (DHD), one of the main bioactive components of Stellera chamaejasme L. (Lang Du), is considered to have antitumor, antibacterial, and antifungal properties. However, the role of DHD in osteoporosis is still elusive. In this study, we demonstrated for the first time that DHD inhibits the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis and bone resorption in a dose- and time-dependent manner without exhibiting cytotoxicity in vitro. Mechanistically, we found that DHD not only represses the expression of osteoclasts marker genes by suppressing RANKL-induced mitogen-activated protein kinase (MAPK) and calcium signaling pathways but also scavenges reactive oxygen species (ROS) through enhancing cytoprotective enzymes expression. Furthermore, DHD inhibits the activation of nuclear factor of activated T cells 1 (NFATc1) during RANKL-induced osteoclasts formation. Preclinical studies revealed that DHD protects against bone loss in ovariectomy (OVX) mice. In sum, our data confirmed that DHD could potentially inhibit osteoclastogenesis by abrogating RANKL-induced MAPK, calcium, and NFATc1 signaling pathways and promoting the expression of ROS scavenging enzymes, thereby preventing OVX-induced bone loss. Thus, DHD may act as a novel therapeutic agent to manage osteoporosis.

Jolkinolide B alleviates renal fibrosis via anti-inflammation and inhibition of epithelial-mesenchymal transition in unilateral ureteral obstruction mice

Renal fibrosis is a critical pathological process lead to a progressive loss of renal function. Jolkinolide B (JB) is a natural compound with anti-inflammatory activity from Euphorbia fischeriana Steud. The study evaluated the effect of JB on renal fibrosis in mice with unilateral ureteral obstruction (UUO). The results showed that JB could decrease renal fibrotic area, reduce phosphorylation of NF-κB p65 and the release of TNF-α, IL-6 and IL-1β, restore the expression of vementin, α-SMA and E-cadherin, as well as TGF-β1 and p-smad2/3. In conclusion, JB might reduce renal fibrosis by inhibiting inflammation induced by NF-κB pathway and EMT mediated by TGF-β1/Smad pathway.

Effects and mechanisms of natural plant active compounds for the treatment of osteoclast-mediated bone destructive diseases

Bone-destructive diseases, caused by overdifferentiation of osteoclasts, reduce bone mass and quality, and disrupt bone microstructure, thereby causes osteoporosis, Paget's disease, osteolytic bone metastases, and rheumatoid arthritis. Osteoclasts, the only multinucleated cells with bone resorption function, are derived from haematopoietic progenitors of the monocyte/macrophage lineage. The regulation of osteoclast differentiation is considered an effective target for the treatment of bone-destructive diseases. Natural plant-derived products have received increasing attention in recent years due to their good safety profile, the preference of natural compounds over synthetic drugs, and their potential therapeutic and preventive activity against osteoclast-mediated bone-destructive diseases. In this study, we reviewed the research progress of the potential antiosteoclast active compounds extracted from medicinal plants and their molecular mechanisms. Active compounds from natural plants that inhibit osteoclast differentiation and functions include flavonoids, terpenoids, quinones, glucosides, polyphenols, alkaloids, coumarins, lignans, and limonoids. They inhibit bone destruction by downregulating the expression of osteoclast-specific marker genes (CTSK, MMP-9, TRAP, OSCAR, DC-STAMP, V-ATPase d2, and integrin av3) and transcription factors (c-Fos, NFATc1, and c-Src), prevent the effects of local factors (ROS, LPS, and NO), and suppress the activation of various signalling pathways (MAPK, NF-κB, Akt, and Ca²⁺). Therefore, osteoclast-targeting natural products are of great value in the prevention and treatment of bone destructive diseases.

Existing knowledge on Euphorbia fischeriana Steud. (Euphorbiaceae): Traditional uses, clinical applications, phytochemistry, pharmacology and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia fischeriana Steud. (Euphorbiaceae) is a perennial herb distributed in grassland, hill slopes or gravel hillside, with average altitude of 100-600 m. The whole grass of E. fischeriana is toxic with roots used as folk medicine to treat Zhushui, dyspepsia, abdominal distension, abdominal pain, cough, as well as external applications such as cure of scabies and tuberculosis of lymph nodes.

AIM OF THE REVIEW

This systematic review aims to provide a detailed and in-depth summary about the reported advances in traditional uses, clinical applications, phytochemistry, pharmacology and toxicity of E. fischeriana, so as to offer fresh ideas and broader vision and insights for subsequent studies.

MATERIALS AND METHODS

Various scientific data bases such as CNKI, Elsevier, Google Scholar, Pubmed, Science Direct, SciFinder Scholar and Web of Science were searched to collect information about E. fischeriana. Other relevant literatures were searched in 'Flora of China Editorial Committee', ancient books, Ph.D and Masters' Dissertation to get more data of E. fischeriana.

RESULTS

A total of 241 chemical constituents have been identified from the roots of E. fischeriana, including diterpenoids, triterpenoids, meroterpenoids, acetophenones, flavonoids, coumarins, steroids, phenolic acids, tannins, etc. Various pharmacological activities have been demonstrated, especially anti-tumor, antibacterial, anti-inflammatory, antiviral and anti-leukemia activities. Moreover, different investigations about clinical uses and toxicology of E. fischeriana indicated that attention should be paid to its usage and dosage.

CONCLUSION

The researches of E. fischeriana are excellent, but gap still remains. As a poisonous traditional Chinese medicine, there are not enough studies on the toxicity of E. fischeriana. In addition, scholars' research on the pharmacological mechanism of E. fischeriana focuses more on the anti-tumor activity, which can be broadened in the future. Presumably, chemical constituents and biological activities of diterpenoids and trace meroterpenoids in E. fischeriana deserve further research in-depth in the future, in order to provide low toxicity and high efficiency lead compounds. Meanwhile, further studies on other medicinal aspects may lay a foundation for the comprehensive development and utilization of E. fischeriana.

Jolkinolide B targets thioredoxin and glutathione systems to induce ROS-mediated paraptosis and apoptosis in bladder cancer cells

Bladder cancer is a clinically heterogeneous disease with a poor prognosis. In the current study, anti-proliferation assay of a Euphorbiaceae diterpenoid library led to the identification of an anti-bladder cancer agent Jolkinolide B (JB). JB showed significant cytotoxicity against a panel of bladder cancer cell lines and suppressed the growth of cisplatin (CDDP)-resistant bladder cancer xenografts in single or combination treatments. Mechanistic study revealed that, besides inducing mitogen-activated protein kinase (MAPK)-related apoptosis, JB could trigger the paraptosis via activation of reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress and extracellular signal-regulated kinase (ERK) pathway. The excessive production of ROS could be induced by JB via inhibition of thioredoxin reductase 1 (TrxR1) and depletion of glutathione (GSH). Collectively, JB that targets thioredoxin and GSH systems to induce two distinct cell death modes may serve as a promising candidate in future anti-bladder cancer drug development.

The Fungal Metabolite (+)-Terrein Abrogates Ovariectomy-Induced Bone Loss and Receptor Activator of Nuclear Factor-κB Ligand-Induced Osteoclastogenesis by Suppressing Protein Kinase-C α/βII Phosphorylation

Osteoporosis is a common disease characterized by a systemic impairment of bone mass and microarchitecture that results in fragility fractures. Severe bone loss due to osteoporosis triggers pathological fractures and consequently decreases the daily life activity and quality of life. Therefore, prevention of osteoporosis has become an important issue to be addressed. We have reported that the fungal secondary metabolite (+)-terrein (TER), a natural compound derived from Aspergillus terreus, has shown receptor activator of nuclear factor-κB ligand (RANKL)–induced osteoclast differentiation by suppressing nuclear factor of activated T-cell 1 (NFATc1) expression, a master regulator of osteoclastogenesis. TER has been shown to possess extensive biological and pharmacological benefits; however, its effects on bone metabolism remain unclear. In this study, we investigated the effects of TER on the femoral bone metabolism using a mouse-ovariectomized osteoporosis model (OVX mice) and then on RANKL signal transduction using mouse bone marrow macrophages (mBMMs). In vivo administration of TER significantly improved bone density, bone mass, and trabecular number in OVX mice (p < 0.01). In addition, TER suppressed TRAP and cathepsin-K expression in the tissue sections of OVX mice (p < 0.01). In an in vitro study, TER suppressed RANKL-induced phosphorylation of PKCα/βII, which is involved in the expression of NFATc1 (p < 0.05). The PKC inhibitor, GF109203X, also inhibited RANKL-induced osteoclastogenesis in mBMMs as well as TER. In addition, TER suppressed the expression of osteoclastogenesis-related genes, such as Ocstamp, Dcstamp, Calcr, Atp6v0d2, Oscar, and Itgb3 (p < 0.01). These results provide promising evidence for the potential therapeutic application of TER as a novel treatment compound against osteoporosis.

19-(Benzyloxy)-19-oxojolkinolide B (19-BJB), an ent-abietane diterpene diepoxide, inhibits the growth of bladder cancer T24 cells through DNA damage

Diterpenoids jolkinolide A and B, were first isolated from Euphorbia fischeriana. In our previous research, 19-(Benzyloxy)-19-oxojolkinolide B (19-BJB), a derivative of jolkinolides, was synthesized as a novel ent -abietane diterpene diepoxide. In this study, 19-BJB showed strong in vitro activity against bladder cancer cell lines. DNA damage which was observed through the interaction of 19-BJB with nucleotide chains and affected DNA repair resulted in the activation of checkpoint kinase 1 (Chk1) and checkpoint kinase 2 (Chk2) in bladder cancer cell lines. In vivo testing in nude mice also proved that 19-BJB revealed a potential inhibitory effect on tumor growth. Additionally, the 3D-QSAR models of jolkinolides were established. Briefly, we proved that 19-BJB could potentially be used as a drug to inhibit the growth of bladder tumor.

Functional metabolomics innovates therapeutic discovery of traditional Chinese medicine derived functional compounds

Traditional Chinese medicines (TCMs) produce chemically diverse functional compounds that are importantly chemical resource for facilitating new drug discovery and development against a diversity of diseases. However, modern exploration of TCM derived functional compounds is significantly hindered by the inefficient elucidation of pharmacological functions over past decades, because conventional research methods are incapable of efficiently elucidating therapeutic potential of TCM conferred by multiple functional compounds. Functional metabolomics has the priority-capacity to characterize systems therapeutic actions of TCM by precisely capturing molecular interactions between disease response metabolite biomarkers (DRMB) and functional compounds (secondary metabolites), which underline pharmacological efficiency and associated therapeutic mechanisms. In this critical review, we innovatively summarize systems therapeutic feature of TCM derived functional compounds from a functional-metabolism perspective, then systems metabolic targets (SMT) identified by functional metabolomics method are strategically proposed to better understanding of therapeutic discovery of TCM derived functional compounds. In addition, we propose the perspective strategy as Spatial Temporal Operative Real Metabolomics (STORM) to considerably improve analytical capacity of functional metabolomics method by selectively incorporating the cutting edge technologies of mass spectrometry imaging, isotope-metabolic fluxomics, synthetic and biosynthetic chemistry, which could considerably enhance the precision and resolution of elucidating pharmacological efficiency and associated therapeutic mechanisms of TCM derived functional compounds. Collectively, such critical review is expected to provide novel perspective-strategy that could significantly improve modern exploration and exploitation of TCM derived functional compounds that further promote new drug discovery and development against the complex diseases.

Circular RNA atlas in osteoclast differentiation with and without alendronate treatment

BACKGROUND

Alendronate (AL) is the most widely used bisphosphonate in the treatment of osteoporosis (OP). However, the role of circular RNAs (circRNAs) in the treatment of OP with AL remains unclear.

METHODS

In this study, we showed that osteoclast (OC) precursors (OPCSs) could be induced into OCs with macrophage colony-stimulating factor (MCSF) and receptor activator of nuclear factor-κB ligand (RANKL) treatment. Subsequently, the OCs were treated with AL. OC differentiation-related biomarkers including RANK, tartrate-resistant acid phosphatase (TRAP), and cathepsin K (CTSK) were analyzed with TRAP staining, quantitative real-time (qPCR), and western blotting. Differentially expressed circRNAs (DECs) were identified among the OPCS, OC, and OC + AL groups. In addition, the expression levels of 10 DECs related to OC differentiation were verified by qPCR.

RESULTS

TRAP staining showed that MCSF and RANKL treatment effectively induced OPCSs to differentiate into OCs. In addition, qPCR and western blot analysis revealed that the three biomarkers of OC (RANK, TRAP, and CTSK) were expressed significantly more in the OC group than those in the OPCS group. In contrast, the mRNA and protein expression levels of these three biomarkers decreased significantly in OCs treated with AL compared with those non-treated OCs. GO analysis of the DECs in the OPCS group vs. the OC group revealed that their functions were mainly related to cell, cell part, binding, and single-organism terms. KEGG analysis of the top 20 DECs in a comparison between the OPCS and OC groups showed that genes involved in mitogen-activated protein kinase signaling were the most common. Results of functional analyses of DECs in an OC vs. OC + AL comparison were similar to those in the OPCS vs. OC comparison. Finally, qPCR showed that, in the OC + AL vs. OC group comparison, the expression levels of seven and three DECs significantly decreased and increased, respectively.

CONCLUSIONS

Having successfully induced OPCSs to differentiate into OCs, we showed that AL suppresses the differentiation of OPCS into OC and that 10 DECs were involved in the regulation of this process. This indicates that these DECs might be important to the treatment of OP.

Optimization of extraction for diterpenoids from Euphorbia fischeriana Steud using response surface methodology and structure identification by UPLC-Q-TOF-MS

Jolkinolide A, jolkinolide B, 17-hydroxyjolkinolide A and 17-hydroxyjolkinolide B are abundant constitutes in Euphorbia Fischeriana Steud and exhibit profound bioactivities. In this study, they were selected as quality control to optimize the extraction of E. fischeriana. Response surface methodology employing Box-Behnken design was applied to test the optimal conditions for the extraction. The optimized conditions for the simultaneous extraction of four diterpenoids from E. fischeriana were: ethanol concentration 100%, extraction temperature 74 °C and extraction time 2.0 h. The extraction contents for jolkinolide A, jolkinolide B, 17-hydroxyjolkinolide A and 17-hydroxyjolkinolide B were 0.1763, 0.9643, 0.4245 and 2.8189 mg/g. The extract obtained under the optimal conditions was injected into UPLC-Q-TOF-MS system. Fifty-one peaks were identified. Two peaks were tentatively identified as new compounds. The compounds were diterpenoids, fatty oil, phenolics and others.

Herbal compounds for rheumatoid arthritis: Literatures review and cheminformatics prediction

Rheumatoid arthritis (RA) is a systemic disease characterized by autoimmunity, joint inflammation, and cartilage destruction, which affects 0.5-1% of the population. Many compounds from herbal medicines show the potentials to treat RA. On this basis, the compounds with good pharmacokinetic behaviors and drug-likeness properties will be further studied and developed. Therefore, the herbal compounds with anti-RA activities were reviewed in this paper, and the cheminformatics tools were used to predict their drug-likeness properties and pharmacokinetic parameters. A total of 90 herbal compounds were analyzed, which were reported to be effective on RA models through anti-inflammation, chondroprotection, immunoregulation, antiangiogenesis, and antioxidation. Most of the herbal compounds have good drug-likeness properties. Most of the compounds can be an alternative and valuable source for anti-RA drug discovery.

Cryptotanshinone inhibits RANKL-induced osteoclastogenesis by regulating ERK and NF-κB signaling pathways

Osteoporosis (OS) is one of the most common healthy problems characterized by low bone mass. Osteoclast, the primary bone-resorbing cell, is responsible for destructive bone diseases including osteoporosis (OS). Cryptotanshinone (CTS), an active component extracted from the root of Salvia miltiorrhiza bunge, has been shown to prevent the destruction of cartilage and the thickening of subchondral bone in mice osteoarthritis models. However, its molecular mechanism in osteoclastogenesis needs to be determined. The aim of the current study was to explore the effect of CTS on osteoclastogenesis and further evaluate the underlying mechanism. Our results showed that CTS inhibited receptor activator of NF-κB ligand (RANKL)-induced the increase in tartrate-resistant acid phosphatase (TRAP) activity in bone marrow-derived macrophages (BMMs). In addition, the expressions of osteoclastogenesis-related marker proteins and nuclear factor of activated T-cells (NFAT) activation were suppressed by CTS treatment in BMMs. Furthermore, CTS attenuated RANKL-induced ERK phosphorylation and NF-κB activation in BMMs. These findings indicated that CTS inhibited RANKL-induced osteoclastogenesis by inhibiting ERK phosphorylation and NF-κB activation in BMMs. Thus, CTS may function as an inhibitor of osteoclastogenesis and may be considered as an alternative medicine for the prevention and treatment of OS.

Terpenes as possible drugs for the mitigation of arthritic symptoms - A systematic review

BACKGROUND

Arthritis is a syndrome associated with exacerbated inflammation, joint destruction and chronic pain and disability. Chronic treatment of arthritis is associated with several side effects and high abandonment. Therefore, there has been an ongoing search for alternative treatments to overcome these problems.

PURPOSE

Natural products, which are already widely used for their biological, cosmetic and pharmacotechnic properties, are a possible source for new drugs. Terpenes, a large class of organic compounds produced mainly by plants and trees, are a promising natural product and have already been shown to be effective in treating chronic pain, particularly of an inflammatory origin.

STUDY DESIGN AND METHODS

This review identifies the main terpenes with anti-arthritic activity reported in the last 10 years. A survey was conducted between December 2017 and June 2018 in the PUBMED, SCOPUS and Science Direct databases using combinations of the descriptors terpenes, arthritis and inflammation.

RESULTS

The results showed that terpenes have promising biological effects in relation to the treatment of arthritis, with the 24 terpenes identified in our survey being effective in the modulation of inflammatory mediators important to the physiopathology of arthritis, such as IL-6, IL-17, TNF-α, NFκB, and COX-2, among others. It is important to note that most of the studies used animal models, which limits, at least in part, the direct translation to humans of the experimental evidence produced by the studies.

CONCLUSION

Together, our finds suggest that terpenes can modulate the immuno-regulatory and destructive tissue events that underlie the clinical presentation and the progression of arthritis and are worthy of further clinical investigation.

Inhibitory effect of Cudratricusxanthone A on osteoclast differentiation and function

BACKGROUND

Cudratricusxanthone A (CTXA) was isolated from Cudrania tricuspidata and its anti-inflammatory, hepatoprotective, and anti-proliferative activities have previously been studied in vitro. However, effects of CTXA on osteoclast differentiation have not been investigated.

PURPOSE

In this study, the effect of CTXA from C. tricuspidata on in vitro osteoclastogenesis was studied.

DESIGN/METHODS

CTXA was isolated from the roots of C. tricuspidata. The effects of CTXA on the RANKL-induced osteoclastogenesis, actin ring formation, and bone resorption were tested by using the RAW 264.7 cells and mouse bone marrow monocytes (BMMs).

RESULTS

The structure of CTXA was identified by comparison with spectral data in the literature. We also checked the effect of CTXA on in vitro osteoclastogenesis. CTXA significantly inhibited the JNK/MAPK signaling pathway without affecting ERK and p38 signaling in RANKL-stimulated RAW 264.7 cells and BMMs. Moreover, it inhibited RANKL-induced expression of c-Fos and NFATc1.

CONCLUSION

In conclusion, CTXA suppresses osteoclast differentiation by inhibiting RANKL-induced MAPK signaling and attenuates bone resorption by disrupting actin ring formation in mature osteoclasts. These results suggest that CTXA inhibits bone resorption through an inhibitory effect on osteoclast formation and function.

Porphyrin Derivatives Inhibit the Interaction between Receptor Activator of NF-κB and Its Ligand

Receptor activator of NF-κB (RANK), a member of the TNF-receptor superfamily, plays an important role in bone resorption and stimulates immune and epithelial cell activation. Denosumab, a human monoclonal antibody that blocks the RANK ligand (RANKL), is approved for the treatment of osteoporosis and bone metastasis. However, a small molecule that inhibits the RANK-RANKL interaction would be beneficial to decrease cost and to facilitate treatments with orally available therapeutic agents. Herein we report the discovery of the first nonpeptidic inhibitors of RANK-RANKL interactions. In screening a chemical library by competitive ELISA, the porphyrin verteporfin was identified as a hit. Derivatives were screened, and the chlorin-macrocycle-containing pheophorbide A and purpurin 18 were found to bind recombinant RANKL, to inhibit RANK-RANKL interactions in the ELISA, and to suppress the RANKL-dependent activation of model cells and the differentiation of RANK-expressing precursors into osteoclasts. This discovery of a family of small molecules that inhibit RANK activation presents an initial basis for further development of nonpeptidic therapeutic agents targeting the interaction between RANK and RANKL.

The RANK/RANKL/OPG system in tumorigenesis and metastasis of cancer stem cell: potential targets for anticancer therapy

The molecular triad involving receptor activator of nuclear factor kβ (RANK)/RANK ligand (RANKL)/osteoprotegerin cytokine system has been well implicated in several physiological and pathological processes including bone metabolism, mammary gland development, regulation of the immune function, tumorigenesis and metastasis of cancer stem cell, thermoregulation, and vascular calcification. However, this review aimed to summarize several original and up-to-date articles focusing on the role of this signaling system in cancer cell development and metastasis as well as potential therapeutic agents targeting any of the three tumor necrotic factor super family proteins and/or their downstream signaling pathways. The RANK/RANKL axis has direct effects on tumor cell development. The system is well involved in the development of several primary and secondary tumors including breast cancer, prostate cancer, bone tumors, and leukemia. The signaling of this triad system has also been linked to tumor invasiveness in the advanced stage. Bone is by far the most common site of cancer metastasis. Several therapeutic agents targeting this system have been developed. Among them, a monoclonal antibody, denosumab, was clinically approved for the treatment of osteoporosis and cancer-related diseases.

Effects of a GSK-3β inhibitor on the renal expression levels of RANK, RANKL and NF-κB in a rat model of diabetic nephropathy

The present study aimed to investigate the effects of glycogen synthase kinase-3β (GSK-3β) on the expression levels of receptor activator of nuclear factor (NF)-κB (RANK), RANK ligand (RANKL) and NF-κB in the renal tissues of rats modeling diabetic nephropathy (DN). The rats were allocated at random into three groups, as follows: Normal control group (NC), the DN model group (DNM group) and the DN model lithium chloride (LiCl) intervention group (DNI group). Urinary proteins were examined by staining with the Coomassie Brilliant Blue dye for 24 h. Histochemical analyses of kidney tissue sections were conducted using hematoxylin and eosin staining, after which the kidney pathology of the rats was observed. In addition, the mRNA and protein expression levels of GSK-3β, RANK, RANKL and NF-κB in the renal tissues were detected using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, respectively. As compared with the NC group, the level of urinary protein was significantly increased in the DNM group (P<0.05); however, as compared with the DNM Group, the level of urinary protein at 12 weeks was significantly decreased in the DNI group (P<0.05). As compared with the NC group, marked pathological changes were detected, and the mRNA and protein expression levels of GSK-3β, RANK, RANKL and NF-κB were significantly increased, in the renal tissues of the DNM group. Conversely, pathological alterations in the renal tissues were attenuated, and the mRNA and protein expression levels of GSK-3β, RANK, RANKL and NF-κB were significantly decreased (P<0.05), in the DNI group, as compared with the DNM group. The results of the present study suggested that GSK-3β, RANK, RANKL and NF-κB may be crucially involved in the development of DN, and that LiCl may effectively attenuate DN by reducing the expression levels of GSK-3β, RANK, RANKL and NF-κB.

Natural products for treatment of bone erosive diseases: The effects and mechanisms on inhibiting osteoclastogenesis and bone resorption

Excessive bone resorption plays a central role on the development of bone erosive diseases, including osteoporosis, rheumatoid arthritis, and periodontitis. Osteoclasts, bone-resorbing multinucleated cells, are differentiated from hemopoietic progenitors of the monocyte/macrophage lineage. Regulation of osteoclast differentiation is considered an effective therapeutic target to the treatment of pathological bone loss. Natural plant-derived products, with potential therapeutic and preventive activities against bone-lytic diseases, have received increasing attention in recent years because of their whole regulative effects and specific pharmacological activities, which are more suitable for long-term use than chemically synthesized medicines. In this review, we summarized the detailed research progress on the active compounds derived from medical plants with potential anti-resorptive effects and their molecular mechanisms on inhibiting osteoclast formation and function. The active ingredients derived from natural plants that are efficacious in suppressing osteoclastogenesis and bone resorption include flavonoids, terpenoids (sesquiterpenoids, diterpenoids, triterpenoids), glycosides, lignans, coumarins, alkaloids, polyphenols, limonoids, quinones and others (steroid, oxoxishhone, fatty acid). Studies have shown that above natural products exert the inhibitory effects via regulating many factors involved in the process of osteoclast differentiation and bone resorption, including the essential cytokines (RANKL, M-CSF), transcription factors (NFATc1, c-Fos), signaling pathways (NF-κB, MAPKs, Src/PI3K/Akt, the calcium ion signaling), osteoclast-specific genes (TRAP, CTSK, MMP-9, integrin β3, OSCAR, DC-STAMP, Atp6v0d2) and local factors (ROS, LPS, NO). The development of osteoclast-targeting natural products is of great value for the prevention or treatment of bone diseases and for bone regenerative medicine.

The treatment of rheumatoid arthritis using Chinese medicinal plants: From pharmacology to potential molecular mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a common worldwide public health problem. Traditional Chinese Medicine (TCM) achieved some results to some extent in the treatment of rheumatoid arthritis (RA). Especially in China, TCM formulas are used in the clinic because of their advantages. Some of these TCM formulas have been used for thousands of years in ancient China, they pays much attention to strengthening healthy qi, cleaning heat, and wet, activating blood, etc. So TCM in anti-RA drug is considered as a simple and effective method. In addition, TCM are also traditionally used as extracts and many Chinese herbs which are considered to be effective for RA. With the advancement of technologies and research methods, researchers have devoted themselves to exploring new therapeutic materials from troves of TCM. The components of TCM are identified and purified, which include alkaloids, coumarins, flavonoids, saponins and so on. However, little or no review works are found in the research literature on the anti-RA drugs from TCM. The present review aims to provide systematically reorganized information on the ethnopharmacology, phytochemistry and pharmacology of TCM used traditionally against RA. The information recorded in this review will provide new directions for researchers in the future.

MATERIALS AND METHODS

Relevant scientific literatures were collected from Chinese traditional books and Chinese Pharmacopoeia. Several important pharmacology data, clinical observations, animal experiments on effects of anti-RA drugs from TCM and their mechanisms were extracted from a library and electric search (Pubmed, PubChem Compound, Science Direct, Spring Link, Elsevier, Web of Science, CNKI, Wan Fang, Bai du, The Plant List, etc.). We collected information published between 2002 and 2015 on Chinese medicine in the treatment of RA. Information was also acquired from local classic herbal literature, conference papers, government reports, and PhD and MSc dissertations.

RESULTS

This review mainly introduces the current research on anti-RA TCM formulas, extracts and compounds from TCM, pharmacological data and potential mechanisms (inhibit osteoclast proliferation, suppress fibroblast-like synoviocytes (FLSs) growth, decrease the expression of inflammatory cytokines, blocking signal pathways, etc.).

CONCLUSIONS

TCM, as a multi-component and multi-target approach, which is a perfect match with the holistic concept of systems biology, is applicable in the treatment of RA. The synergistic connections of Chinese herbs and mechanisms of related active compounds on RA increase the trust for TCM. TCM as alternative remedies for RA not only has an important position in the world market, but also has an irreplaceable role in the treatment of RA in future.

Protective effect of Jolkinolide B on LPS-induced mouse acute lung injury

Jolkinolide B (JB), an ent-abietane diterpenoid, isolated from the dried root of Euphorbia fischeriana, has been reported to have potent anti-tumor and anti-inflammatory activities. However, the effects of JB on acute lung injury (ALI) and underlying molecular mechanisms have not been investigated. The present study aimed to investigate the effect of JB on lipopolysaccharide (LPS)-induced ALI. Male C57BL/6 mice were pretreated with dexamethasone or JB 1h before intranasal instillation of LPS. The results showed that JB markedly attenuated LPS-induced histological alterations, lung edema, inflammatory cell infiltration, myeloperoxidase (MPO) activity as well as the production of TNF-α, IL-6 and IL-1β. Furthermore, JB also significantly inhibited LPS-induced the degradation of IκBα and phosphorylation of NF-κB p65 and MAPK. Therefore, our study provides the first line of evidence that pretreatment of JB has a protective effect on LPS-induced ALI in mice. The anti-inflammatory mechanism of JB may be attributed to its suppression of NF-κB and MAPK activation.

Urokinase receptor mediates osteoclastogenesis via M-CSF release from osteoblasts and the c-Fms/PI3K/Akt/NF-κB pathway in osteoclasts

Bone remodeling is a dynamic process based on a fine-tuned balance between formation and degradation of bone. Osteoblasts (OBLs) are responsible for bone formation and bone resorption is mediated by osteoclasts (OCLs). The mechanisms regulating the OBL-OCL balance are critical in health and disease; however, they are still far from being understood. We reported recently that the multifunctional urokinase receptor (uPAR) mediates osteogenic differentiation of mesenchymal stem cells (MSCs) to OBLs and vascular calcification in atherosclerosis. Here, we address the question of whether uPAR may also be engaged in regulation of osteoclastogenesis. We show that uPAR mediates this process in a dual fashion. Thus, uPAR affected OBL-OCL interplay. We observed that osteoclastogenesis was significantly impaired in co-culture of monocyte-derived OCLs and in OBLs derived from MSCs lacking uPAR. We show that expression and release, from OBLs, of macrophage colony-stimulating factor (M-CSF), which is indispensable for OCL differentiation, was inhibited by uPAR loss. We further found that uPAR, on the other hand, controlled formation, differentiation, and functional properties of macrophage-derived OCLs. Expression of osteoclastogenic markers, such as tartrate-resistant acid phosphatase (TRAP) and cathepsin K, was impaired in OCLs derived from uPAR-deficient macrophages. The requirement of uPAR for osteoclastogenesis was further confirmed by immunocytochemistry and in bone resorption assay. We provide evidence that the underlying signaling mechanisms involve uPAR association with the M-CSF binding receptor c-Fms followed by c-Fms phosphorylation and activation of the PI3K/Akt/NF-κB pathway in OCLs. We further show that uPAR uses this pathway to regulate a balance between OCL differentiation, apoptosis, and cell proliferation. Our study identified uPAR as an important and multifaceted regulator of OBL-OCL molecular interplay that may serve as an attractive target in bone disease and ectopic calcification.