Anemonin attenuates osteoarthritis progression through inhibiting the activation of IL-1β/NF-κB pathway

Emerging Roles of Macrophage Polarization in Osteoarthritis: Mechanisms and Therapeutic Strategies

Osteoarthritis (OA) is the most common chronic degenerative joint disease in middle-aged and elderly people, characterized by joint pain and dysfunction. Macrophages are key players in OA pathology, and their activation state has been studied extensively. Various studies have suggested that macrophages might respond to stimuli in their microenvironment by changing their phenotypes to pro-inflammatory or anti-inflammatory phenotypes, which is called macrophage polarization. Macrophages accumulate and become polarized (M1 or M2) in many tissues, such as synovium, adipose tissue, bone marrow, and bone mesenchymal tissues in joints, while resident macrophages as well as other stromal cells, including fibroblasts, chondrocytes, and osteoblasts, form the joint and function as an integrated unit. In this study, we focus exclusively on synovial macrophages, adipose tissue macrophages, and osteoclasts, to investigate their roles in the development of OA. We review recent key findings related to macrophage polarization and OA, including pathogenesis, molecular pathways, and therapeutics. We summarize several signaling pathways in macrophage reprogramming related to OA, including NF-κB, MAPK, TGF-β, JAK/STAT, PI3K/Akt/mTOR, and NLRP3. Of note, despite the increasing availability of treatments for osteoarthritis, like intra-articular injections, surgery, and cellular therapy, the demand for more effective clinical therapies has remained steady. Therefore, we also describe the current prospective therapeutic methods that deem macrophage polarization to be a therapeutic target, including physical stimulus, chemical compounds, and biological molecules, to enhance cartilage repair and alleviate the progression of OA.

Anemonin ameliorates human diploid fibroblasts 2BS and IMR90 cell senescence by PARP1-NAD+-SIRT1 signaling pathway

OBJECTIVE

Aging becomes the most predominant risk factor for all age-associated pathological conditions with the increase of life expectancy and the aggravation of social aging. Slowing down the speed of aging is considered an effective way to improve health, but so far, effective anti-aging methods are relatively lacking.

METHODS

Anemonin (ANE) was screened from eight existing small-molecule compounds by cell viability assay. The function of ANE was determined by the analysis of cell proliferation, β -galactosidase (SA-β -Gal) activity, cell cycle, SASP secretion, NAD+/NADH ratio, and other aging-related indicators. The targets of ANE were predicted by Drug Target Prediction System (DTPS) and Swiss Targe Prediction System. The effect of ANE on PARP-1-NAD+-SIRT1 signaling pathway was assessed by quantitative reverse-transcription polymerase chain reaction (RT-PCR), Western blot, PARP1, NAD+ and SIRT1 activity detection.

RESULTS

ANE can delay cell senescence; PARP1 is one of the targets of ANE and plays a crucial role in ANE anti-aging; ANE release more NAD+ by inhibiting PARP1 activity, thereby conversely promoting the function of SIRT1 and delay cell senescence.

CONCLUSIONS

Our study indicates that ANE can delay cellular senescence through the PARP1-NAD+-SIRT1 signaling pathway, which may be considered as an effective anti-aging strategy.

Lubricating Microneedles System with Multistage Sustained Drug Delivery for the Treatment of Osteoarthritis

Osteoarthritis (OA) is a typical joint degenerative disease that is prevalent worldwide and significantly affects the normal activities of patients. Traditional treatments using diclofenac (DCF) as an anti-inflammatory drug by oral administration and transdermal delivery have many inherent deficiencies. In this study, a lubricating microneedles (MNs) system for the treatment of osteoarthritis with multistage sustained drug delivery and great reduction in skin damage during MNs penetration is developed. The bilayer dissolvable MNs system, namely HA-DCF@PDMPC, is prepared by designating the composite material of hyaluronic acid (HA) and covalently conjugated drug compound (HA-DCF) as the MNs tips and then modifying the surface of MNs tips with a self-adhesive lubricating copolymer (PDMPC). The MNs system is designed to achieve sustained drug release of DCF via ester bond hydrolysis, physical diffusion from MNs tips, and breakthrough of lubrication coating. Additionally, skin damage is reduced due to the presence of the lubrication coating on the superficial surface. Therefore, the lubricating MNs with multistage sustained drug delivery show good compliance as a transdermal patch for OA treatment, which is validated from anti-inflammatory cell tests and therapeutic animal experiments, down-regulating the expression levels of pro-inflammatory factors and alleviating articular cartilage destruction.

A Blend of Tamarindus Indica and Curcuma Longa Extracts Alleviates Monosodium Iodoacetate (MIA)-Induced Osteoarthritic Pain and Joint Inflammation in Rats

BACKGROUND AND OBJECTIVE

NXT15906F6 (TamaFlexTM) is a proprietary herbal composition containing Tamarindus indica seeds and Curcuma longa rhizome extracts. NXT15906F6 supplementation has been shown clinically effective in reducing knee joint pain and improving musculoskeletal functions in healthy and knee osteoarthritis (OA) subjects. The objective of the present study was to assess the possible molecular basis of the anti-OA efficacy of NXT15906F6 in a monosodium iodoacetate (MIA)-induced model of OA in rats.

METHODS

Healthy male Sprague Dawley rats (age: 8-9 wk body weight, B.W.: 225-308 g (n = 12) were randomly assigned to one of the six groups, (a) vehicle control, (b) MIA control, (c) Celecoxib (10 mg/kg B.W.), (d) TF-30 (30 mg/kg B.W.), (e) TF-60 (60 mg/kg B.W.), and (f) TF-100 (100 mg/kg B.W.). OA was induced by an intra-articular injection of 3 mg MIA into the right hind knee joint. The animals received either Celecoxib or TF through oral gavage over 28 days. The vehicle control animals received intra-articular sterile normal saline.

RESULTS

Post-treatment, NXT15906F6 groups showed significant (p < 0.05) dose-dependent pain relief as evidenced by improved body weight-bearing capacity on the right hind limb. NXT15906F6 treatment also significantly reduced the serum tumor necrosis factor-α (TNF-α, p < 0.05) and nitrite (p < 0.05) levels in a dose-dependent manner. mRNA expression analyses revealed the up-regulation of collagen type-II (COL2A1) and down-regulation of matrix metalloproteinases (MMP-3, MMP-9 and MMP-13) in the cartilage tissues of NXT15906F6-supplemented rats. Cyclooxygenase-2 and inducible nitric oxide synthase (iNOS) protein expressions were down-regulated. Decreased immunolocalization of NF-κβ (p65) was observed in the joint tissues of NXT15906F6-supplemented rats. Furthermore, microscopic observations revealed that NXT15906F6 preserved MIA-induced rats' joint architecture and integrity.

CONCLUSION

NXT15906F6 reduces MIA-induced joint pain, inflammation, and cartilage degradation in rats.

Anemonin inhibits sepsis-induced acute kidney injury via mitigating inflammation and oxidative stress

Elevated inflammation and oxidative stress (OS) are the main pathologic features of acute kidney injury (AKI)-caused by sepsis. Here, we made an investigation into the protective effects of the natural compound Anemonin (ANE) on sepsis-induced AKI both in vitro and in vivo. Lipopolysaccharide (LPS) was applied to construct an in vitro AKI model in renal tubular epithelial cells, and the septic C57BL/6J mouse model was constructed via cecal ligation and puncture (CLP). Cell viability and apoptosis were detected. The levels of p53, Bax, Bcl2, Caspase3, Caspase8, Caspase9, AMP-activated protein kinase (AMPK), Sirt-1, and forkhead box O3 were determined by Western Blot or RT-PCR. The reactive oxygen species level and OS markers were measured. Furthermore, the pathological changes of kidneys were evaluated by hematoxylin-eosin staining and immunohistochemistry. As per the information presented, ANE improved LPS-elicited apoptosis, inflammatory response, and OS in a dose-dependent pattern in renal tubular epithelial cells. Besides, ANE activated the AMPK/Sirt-1 pathway, and the AMPK inhibitor (Compound C) and Sirt-1 inhibitor (EX-527) significantly attenuated ANE-mediated protection on renal tubular epithelial cells. In vivo, ANE mitigated the levels of serum creatinine and urea nitrogen in the CLP-induced mouse sepsis model, reduced the renal tissue injury score, and attenuated OS, inflammation, and apoptosis levels in the kidney. Taken together, this study suggested that ANE has protective effects in sepsis-triggered AKI through repressing inflammation, OS, and cell apoptosis by activating the AMPK/Sirt-1 pathway.

Pachymic acid suppresses the inflammatory response of chondrocytes and alleviates the progression of osteoarthritis via regulating the Sirtuin 6/NF-κB signal axis

Articular cartilage degeneration is a characteristic pathological change of osteoarthritis (OA). Pachymic acid (PA) is an active ingredient found in Poria cocos. Previous studies have shown that PA has anti-inflammatory effects on a variety of diseases. However, the role of PA in OA and its underlying mechanisms has not been clearly elucidated. In this study, we investigated potential protective effect of PA on OA through cell experiments in vitro and animal experiments in vivo. PA inhibited interleukin-1β-induced inflammatory mediator production in chondrocytes, which includes nitric oxide, inducible nitric oxide synthase, prostaglandin E2, cyclooxygenase-2, tumor necrosis factor alpha and interleukin-6. Meanwhile, PA also reversed the up-regulation of matrix metalloproteinase-3 and thrombospondin motifs 5, and the down-regulation of collagen type II and aggrecan in IL-1β-treated chondrocytes. Mechanistically, our findings revealed that PA-mediated overexpression of SIRT6 inhibited the NF-κB signaling pathway. In vivo, PA contributes to improve cartilage damage in the mouse OA model. In summary, PA inhibited IL-1β-induced inflammation and extracellular matrix degeneration by promoting SIRT6 expression and inhibiting the NF-κB signaling pathway, which indicates that PA is beneficial for the treatment of OA.

Betulinic Acid Attenuates Osteoarthritis via Limiting NLRP3 Inflammasome Activation to Decrease Interleukin-1β Maturation and Secretion

Introduction

Osteoarthritis (OA) is the most common degenerative joint disorder. Prior studies revealed that activation of NLRP3 inflammasome could promote the activation and secretion of interleukin-1β (IL-1β), which has an adverse effect on the progression of OA. Betulinic acid (BA) is a compound extract of birch, whether it can protect against OA and the mechanisms involved are still unknown.

Materials and Methods

In vivo experiments, using gait analysis, ELISA, micro-CT, and scanning electron microscopy (SEM), histological staining, immunohistological (IHC) and immunofluorescence (IF) staining, and atomic force microscopy (AFM) to assess OA progression after intraperitoneal injection of 5 and 15 mg/kg BA in an OA mouse model. In vitro experiments, caspase-1, IL-1β, and the N-terminal fragment of gasdermin D (GSDMD-NT) were measured in bone marrow-derived macrophages (BMDMs) by using ELISA, western blot, and immunofluorescence staining.

Results

We demonstrated that OA progression can be postponed with intraperitoneal injection of 5 and 15 mg/kg BA in an OA mouse model. Specifically, BA postponed DMM-induced cartilage deterioration, alleviated subchondral bone sclerosis, and relieved synovial inflammation. In vitro studies, the activated NLRP3 inflammasome produces mature IL-1β by facilitating the cleavage of pro-IL-1β, and BA could inhibit the activation of NLRP3 inflammasome in BMDMs.

Conclusions

Taken together, our analyses revealed that BA attenuates OA via limiting NLRP3 inflammasome activation to decrease the IL-1β maturation and secretion.

Prevention and treatment of inflammatory arthritis with traditional Chinese medicine: Underlying mechanisms based on cell and molecular targets

Inflammatory arthritis, primarily including rheumatoid arthritis, osteoarthritis and ankylosing spondylitis, is a group of chronic inflammatory diseases, whose general feature is joint dysfunction with chronic pain and eventually causes disability in older people. To date, both Western medicine and traditional Chinese medicine (TCM) have developed a variety of therapeutic methods for inflammatory arthritis and achieved excellent results. But there is still a long way to totally cure these diseases. TCM has been used to treat various joint diseases for thousands of years in Asia. In this review, we summarize clinical efficacies of TCM in inflammatory arthritis treatment after reviewing the results demonstrated in meta-analyses, systematic reviews, and clinical trials. We pioneered taking inflammatory arthritis-related cell targets of TCM as the entry point and further elaborated the molecular targets inside the cells of TCM, especially the signaling pathways. In addition, we also briefly discussed the relationship between gut microbiota and TCM and described the role of drug delivery systems for using TCM more accurately and safely. We provide updated and comprehensive insights into the clinical application of TCM for inflammatory arthritis treatment. We hope this review can guide and inspire researchers to further explore mechanisms of the anti-arthritis activity of TCM and make a great leap forward in comprehending the science of TCM.

Anemonin reduces hydrogen peroxide-induced oxidative stress, inflammation and extracellular matrix degradation in nucleus pulposus cells by regulating NOX4/NF-κB signaling pathway

BACKGROUND

Excessive oxidative stress plays a critical role in the progression of various diseases, including intervertebral disk degeneration (IVDD). Recent studies have found that anemonin (ANE) possesses antioxidant and anti-inflammatory effects. However, the role of ANE in IVDD is still unclear. Therefore, this study investigated the effect and mechanism of ANE on H₂O₂ induced degeneration of nucleus pulposus cells (NPCs).

METHODS

NPCs were pretreated with ANE, and then treated with H₂O₂. NOX4 was upregulated by transfection of pcDNA-NOX4 into NPCs. Cytotoxicity was detected by MTT, oxidative stress-related indicators and inflammatory factors were measured by ELISA, mRNA expression was assessed by RT-PCR, and protein expression was tested by western blot.

RESULTS

ANE attenuated H₂O₂-induced inhibition of NPCs activity. H₂O₂ enhanced oxidative stress, namely, increased ROS and MDA levels and decreased SOD level. However, these were suppressed and pretreated by ANE. ANE treatment repressed the expression of inflammatory factors (IL-6, IL-1β and TNF-α) in H₂O₂-induced NPCs. ANE treatment also prevented the degradation of extracellular matrix induced by H₂O₂, showing the downregulation of MMP-3, 13 and ADAMTS-4, 5 and the upregulation of collagen II. NOX4 is a key factor regulating oxidative stress. Our study confirmed that ANE could restrain NOX4 and p-NF-κB. In addition, overexpression of NOX4 counteracted the antioxidant and anti-inflammatory activities of ANE in H₂O₂-induced NPCs, and the inhibition of the degradation of extracellular matrix induced by ANE was also reversed by overexpression of NOX4.

CONCLUSION

ANE repressed oxidative stress, inflammation and extracellular matrix degradation in H₂O₂-induced NPCs by inhibiting NOX4/NF-κB pathway. Our study indicated that ANE might be a candidate drug for the treatment of IVDD.

Recent Advances in Small Molecule Inhibitors for the Treatment of Osteoarthritis

Osteoarthritis refers to a degenerative disease with joint pain as the main symptom, and it is caused by various factors, including fibrosis, chapping, ulcers, and loss of articular cartilage. Traditional treatments can only delay the progression of osteoarthritis, and patients may need joint replacement eventually. As a class of organic compound molecules weighing less than 1000 daltons, small molecule inhibitors can target proteins as the main components of most drugs clinically. Small molecule inhibitors for osteoarthritis are under constant research. In this regard, by reviewing relevant manuscripts, small molecule inhibitors targeting MMPs, ADAMTS, IL-1, TNF, WNT, NF-κB, and other proteins were reviewed. We summarized these small molecule inhibitors with different targets and discussed disease-modifying osteoarthritis drugs based on them. These small molecule inhibitors have good inhibitory effects on osteoarthritis, and this review will provide a reference for the treatment of osteoarthritis.

Small molecule inhibitors of osteoarthritis: Current development and future perspective

Osteoarthritis (OA) is one of the common degenerative joint diseases in clinic. It mainly damages articular cartilage, causing pain, swelling and stiffness around joints, and is the main cause of disability of the elderly. Due to the unclear pathogenesis of osteoarthritis and the poor self-healing ability of articular cartilage, the treatment options for this disease are limited. At present, NSAIDs, Glucocorticoid and Duloxetine are the most commonly used treatment choice for osteoarthritis. Although it is somewhat effective, the adverse reactions are frequent and serious. The development of safer and more effective anti-osteoarthritis drugs is essential and urgent. This review summarizes recent advances in the pharmacological treatment of OA, focusing on small molecule inhibitors targeting cartilage remodeling in osteoarthritis as well as the research idea of reducing adverse effects by optimizing the dosage form of traditional drugs for the treatment of osteoarthritis. It should provide a reference for exploration of new potential treatment options.

miR-3960 from Mesenchymal Stem Cell-Derived Extracellular Vesicles Inactivates SDC1/Wnt/β-Catenin Axis to Relieve Chondrocyte Injury in Osteoarthritis by Targeting PHLDA2

Osteoarthritis (OA) is a serious disease of the articular cartilage characterized by excessive inflammation. Lately, mesenchymal stem cell- (MSC-) derived extracellular vesicles (EVs) have been proposed as a novel strategy for the treatment of OA. We aimed to investigate the effects of EV-encapsulated miR-3960 derived from MSCs on chondrocyte injury in OA. The cartilage tissues from OA patients were collected to experimentally determine expression patterns of miR-3960, PHLDA2, SDC1, and β-catenin. Next, luciferase assay was implemented to testify the binding affinity among miR-3960 and PHLDA2. EVs were isolated from MSCs and cocultured with IL-1β-induced OA chondrocytes. Afterwards, cellular biological behaviors and levels of extracellular matrix- (ECM-) related protein anabolic markers (collagen II and aggrecan), catabolic markers (MMP13 and ADAMTS5), and inflammatory factors (IL-6 and TNF-α) in chondrocytes were assayed upon miR-3960 and/or PHLDA2 gain- or loss-of-function. Finally, the effects of miR-3960 contained in MSC-derived EVs in OA mouse models were also explored. MSCs-EVs could reduce IL-1β-induced inflammatory response and extracellular matrix (ECM) degradation in chondrocytes. miR-3960 expression was downregulated in cartilage tissues of OA patients but enriched in MSC-derived EVs. miR-3960 could target and inhibit PHLDA2, which was positively correlated with SDC1 and Wnt/β-catenin pathway activation. miR-3960 shuttled by MSC-derived EVs protected against apoptosis and ECM degradation in chondrocytes. In vivo experiment also confirmed that miR-3960 alleviated chondrocyte injury in OA. Collectively, MSC-derived EV-loaded miR-3960 downregulated PHLDA2 to inhibit chondrocyte injury via SDC1/Wnt/β-catenin.

Small molecules of herbal origin for osteoarthritis treatment: in vitro and in vivo evidence

Osteoarthritis (OA) is one of the most common musculoskeletal degenerative diseases and contributes to heavy socioeconomic burden. Current pharmacological and conventional non-pharmacological therapies aim at relieving the symptoms like pain and disability rather than modifying the underlying disease. Surgical treatment and ultimately joint replacement arthroplasty are indicated in advanced stages of OA. Since the underlying mechanisms of OA onset and progression have not been fully elucidated yet, the development of novel therapeutics to prevent, halt, or reverse the disease is laborious. Recently, small molecules of herbal origin have been reported to show potent anti-inflammatory, anti-catabolic, and anabolic effects, implying their potential for treatment of OA. Herein, the molecular mechanisms of these small molecules, their effect on physiological or pathological signaling pathways, the advancement of the extraction methods, and their potential clinical translation based on in vitro and in vivo evidence are comprehensively reviewed.

Thermal and wine processing enhanced Clematidis Radix et Rhizoma ameliorate collagen Ⅱ induced rheumatoid arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Clematidis Radix et Rhizoma, a kind of traditional Chinese medicine, is derived from Clematis chinensis Osbeck, Clematis hexapetala Pall. and Clematis manshurica Rupr. This herb shows great effects on expelling wind and dispelling dampness in ancient and it has anti-inflammatory and analgesic activity in modern clinical application.

AIM OF THE STUDY

This experiment aimed to research anti-rheumatoid arthritis effect of crude and wine processed RC based on glycolysis metabolism to provide new ideas treating RA.

MATERIALS AND METHODS

Network pharmacology was applied to preliminarily forecast the potential pathways of common targets of RC and RA. RAW264.7 macrophages were induced by LPS, NO production, glucose uptake, lactate production, ROS and MMP were detected as instructions in vitro. ELISA was used to measure the content of HK2, PKM2 and LDHA involving in glycolysis process. Gut microbiota was analyzed by 16S rRNA gene amplicon sequencing in CIA rats.

RESULTS

Crude and wine processed RC had good anti-inflammatory effect by reducing NO in RAW264.7 macrophages and ameliorating inflammatory infiltration and cartilage surface erosion in CIA rats. Whether in LPS-induced macrophages or CIA rats, crude and wine processed RC could inhibit glycolysis by down-regulating the expression of PKM2, causing less glucose uptake and lactic acid, which lead to less ROS and higher MMP to normal. PI3K-AKT and HIF-1α pathways were deduced to possibly play a crucial part in controlling glycolysis metabolism by network pharmacology analysis. Besides, it was displayed that Firmicutes and Bacteroidetes were prominent gut microbiota in CIA rats feces. CC-H and PZ-H groups could both increase the relative abundance of Firmicutes and decrease Bacteroidetes. These microbiota also played a role in RA pathological process via involving in energy metabolism, carbohydrate metabolism and immune system.

CONCLUSION

Crude and wine processed RC have a good influence in ameliorating rheumatoid arthritis by inhibiting glycolysis and modulating gut microbiota together.

Anti-inflammatory effects of anemonin on acute ulcerative colitis via targeted regulation of protein kinase C-θ

Background

Ulcerative colitis (UC) is an inflammatory bowel disease that causes continuous mucosal inflammation. Anemonin is a natural molecule from the Ranunculaceae and Gramineae plants that exerts anti-inflammatory properties. This study aimed to explore the effects and mechanisms of anemonin on UC.

Methods

C57BL/6 mice were administered dextran sulphate sodium (DSS; 3% [w/v]) to establish an animal model of UC. Mice were treated with an intraperitoneal injection of anemonin. Body weight and the disease activity index (DAI) were recorded. Haematoxylin and eosin staining, RT-qPCR, ELISA, and western blotting were performed to evaluate the histopathological changes and tissue inflammation. HT-29 cells were treated with lipopolysaccharide (LPS) and anemonin. Cell inflammation was evaluated using RT-qPCR and western blotting. The target proteins of anemonin were predicted using bioinformatics analysis and confirmed in vitro and in vivo.

Results

Anemonin improved DSS-induced body weight loss, shortened colon length, increased DAI, and induced pathological changes in the colon tissue of mice. Anemonin inhibited DSS-induced colon tissue inflammation as the release of IL-1β, TNF-α, and IL-6 was significantly suppressed. Additionally, anemonin attenuated LPS-induced cytokine production in HT-29 cells. PKC-θ was predicted as a target protein of anemonin. Anemonin did not affect PRKCQ gene transcription, but inhibited its translation. PRKCQ overexpression partially reversed the protective effects of anemonin on HT-29 cells. Adeno-associated virus delivery of the PRKCQ vector significantly reversed the protective effects of anemonin on the mouse colon.

Conclusions

Anemonin has the potential to treat UC. The anti-inflammatory effects of anemonin may be mediated through targeting PKC-θ.

Circ_0008365 Suppresses Apoptosis, Inflammation and Extracellular Matrix Degradation of IL-1β-treated Chondrocytes in Osteoarthritis by Regulating miR-324-5p/BMPR2/NF-κB Signaling Axis

BACKGROUND

Recent studies have revealed that circular RNAs (circRNAs) play crucial roles in the progression of osteoarthritis (OA). This study aimed to investigate the biological function and regulatory mechanism of circ_0008365 in OA.

METHODS

OA cell model in vitro was established in chondrocytes by treatment with Interleukin-1β (IL-1β). The levels of inflammatory cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The expression levels of circ_0008365, microRNA-324-5p (miR-324-5p) and bone morphogenetic protein type 2 receptor (BMPR2) were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was assessed using flow cytometry and caspase3 activity assays. The protein expression was determined via a western blot assay. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and RNA pull-down assays were used to analyze the correlation between targets.

RESULTS

IL-1β level and miR-324-5p expression were increased, while circ_0008365 was downregulated in OA patients. IL-1β treatment-induced cell apoptosis, inflammation and extracellular matrix (ECM) degradation in chondrocytes. Besides, circ_0008365 overexpression partly relieved IL-1β-induced cell damage in chondrocytes. Circ_0008365 could interact with miR-324-5p, and BMPR2 was a downstream target of miR-324-5p. Overexpression of miR-324-5p or BMPR2 knockdown partly overturned the inhibiting effect of circ_0008365 on cell damage in IL-1β-induced chondrocytes. In addition, circ_0008365 inactivated NF-κB pathway via regulating miR-324-5p/BMPR2 axis.

CONCLUSION

Circ_0008365 reduced IL-1β-induced cell damage in chondrocytes via inactivating NF-κB signaling pathway and regulating miR-324-5p/BMPR2 axis.Abbreviations OA: osteoarthritis; BMPR2: bone morphogenetic protein type 2 receptor.

In Vitro Antileishmanial and Antischistosomal Activities of Anemonin Isolated from the Fresh Leaves of Ranunculus multifidus Forsk

Leishmaniasis and schistosomiasis are neglected tropical diseases (NTDs) infecting the world’s poorest populations. Effectiveness of the current antileishmanial and antischistosomal therapies are significantly declining, which calls for an urgent need of new effective and safe drugs. In Ethiopia fresh leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of various ailments including leishmaniasis and eradication of intestinal worms. In the current study, anemonin isolated from the fresh leaves of R. multifidus was assessed for its in vitro antileishmanial and antischistosomal activities. Anemonin was isolated from the hydro-distilled extract of the leaves of R. multifidus. Antileishmanial activity was assessed on clinical isolates of the promastigote and amastigote forms of Leishmania aethiopica and L. donovani clinical isolates. Resazurin reduction assay was used to determine antipromastigote activity, while macrophages were employed for antiamastigote and cytotoxicity assays. Antischistosomal assays were performed against adult Schistosoma mansoni and newly transformed schistosomules (NTS). Anemonin displayed significant antileishmanial activity with IC₅₀ values of 1.33 nM and 1.58 nM against promastigotes and 1.24 nM and 1.91 nM against amastigotes of L. aethiopica and L. donovani, respectively. It also showed moderate activity against adult S. mansoni and NTS (49% activity against adult S. mansoni at 10 µM and 41% activity against NTS at 1 µM). The results obtained in this investigation indicate that anemonin has the potential to be used as a template for designing novel antileishmanial and antischistosomal pharmacophores.

Avicularin suppresses cartilage extracellular matrix degradation and inflammation via TRAF6/MAPK activation

BACKGROUND

Osteoarthritis (OA) is an intractable degenerative disease of the whole joint, which is characterized by synovitis inflammation, cartilage damage, and chronic pain. Tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) performs an important role in OA.

PURPOSE

We aim to investigate avicularin to protect cartilage extracellular matrix degradation (ECM) and suppresses inflammation both in rat and human chondrocytes.

METHODS

5-Ethynyl-2'-deoxyuridine (EdU) staining, Quantitative real-time PCR, TRAF6 plasmid transfection, Western blot, Measurement of nitric oxide (NO), ROS detection and Immunofluorescence were utilized in vitro. micro-CT scanning, Safranin O-Fast Green, toluidine blue and immunohistochemistry staining were performed in vivo.

RESULTS

In vitro, avicularin attenuates the degradation of ECM and inflammation, which could inhibit the activation of TRAF6/MAPK pathway via targeting TRAF6. Increased MMP3 and MMP13 expressions and decreased Aggrecan and Collagen Ⅱ levels were observed in anterior cruciate ligament transection (ACLT) induced osteoarthritic rats. Interestingly, intra-articular injection of avicularin attenuates this phenomenon.

CONCLUSIONS

Taken together, our results indicate that avicularin suppresses cartilage extracellular matrix degradation and inflammation via TRAF6/MAPK activation by targeting TRAF6. These observations identify TRAF6 as a relevant drug target, and avicularin may as a potential therapeutic agent in osteoarthritis.

Pseudolaric acid B ameliorates synovial inflammation and vessel formation by stabilizing PPARγ to inhibit NF-κB signalling pathway

Synovial macrophage polarization and inflammation are essential for osteoarthritis (OA) development, yet the molecular mechanisms and regulation responsible for the pathogenesis are still poorly understood. Here, we report that pseudolaric acid B (PAB) attenuated articular cartilage degeneration and synovitis during OA. PAB, a diterpene acid, specifically inhibited NF-κB signalling and reduced the production of pro-inflammatory cytokines, which further decreased M1 polarization and vessel formation. We further provide in vivo and in vitro evidences that PAB suppressed NF-κB signalling by stabilizing PPARγ. Using PPARγ antagonist could abolish anti-inflammatory effect of PAB and rescue the activation of NF-κB signalling during OA. Our findings identify a previously unrecognized role of PAB in the regulation of OA and provide mechanisms by which PAB regulates NF-κB signalling through PPARγ, which further suggest targeting synovial inflammation or inhibiting vessel formation at early stage could be an effective preventive strategy for OA.

Quercitrin alleviates cartilage extracellular matrix degradation and delays ACLT rat osteoarthritis development: An in vivo and in vitro study

Introduction: Disruptions of extracellular matrix (ECM) degradation homeostasis play a significant role in the pathogenesis of osteoarthritis (OA). Matrix metalloproteinase 13 (MMP13) and collagen Ⅱ are important components of ECM. Earlier we found that quercitrin could significantly decrease MMP13 gene expression and increase collagen Ⅱ gene expression in IL-1β-induced rat chondrocytes and human chondrosarcoma (SW1353) cells. Objectives: The effects and mechanism of quercitrin on OA were explored. Methods: Molecular mechanisms of quercitrin on OA were studied in vitro in primary chondrocytes and SW1353 cells. An anterior cruciate ligament transection (ACLT) rat model of OA was used to investigate the effect of quercitrin in vivo. Micro-CT analysis and Safranin O-Fast Green Staining of knee joint samples were performed to observe the damage degree of tibial subchondral bone. Immunohistochemistry of knee joint samples were conducted to observe the protein level of MMP13, collagen Ⅱ and p110α in articular cartilage. Results: In vitro, quercitrin promoted cell proliferation and delayed ECM degradation by regulating MMP13 and collagen II gene and protein expressions. Moreover, quercitrin activated the Phosphatidylinositol 3-kinase p110α (p110α)/AKT/mTOR signaling pathway by targeting p110α. We also firstly showed that the gene expression level of p110α was remarkably decreased in cartilage of OA patients. The results showed that intra-articular injection of quercitrin increased bone volume/tissue volume of tibial subchondral bone and cartilage thickness and reduced the Osteoarthritis Research Society International scores in OA rats. Meanwhile, immunohistochemical results showed that quercitrin exerted anti-OA effect by delaying ECM degradation. Conclusion: These findings suggested that quercitrin may be a prospective disease-modifying OA drug for prevention and treatment of early stage OA.

A Novel Multiplex Based Platform for Osteoarthritis Drug Candidate Evaluation

Osteoarthritis (OA) is characterized by irreversible cartilage degradation with very limited therapeutic interventions. Drug candidates targeted at prototypic players had limited success until now and systems based approaches might be necessary. Consequently, drug evaluation platforms should consider the biological complexity looking beyond well-known contributors of OA. In this study an ex vivo model of cartilage degradation, combined with measuring releases of 27 proteins, was utilized to study 9 drug candidates. After an initial single drug evaluation step the 3 most promising compounds were selected and employed in an exhaustive combinatorial experiment. The resulting most and least promising treatment candidates were selected and validated in an independent study. This included estimation of mechanical properties via finite element modelling (FEM) and quantification of cartilage degradation as glycosaminoglycan (GAG) release. The most promising candidate showed increase of Young's modulus, decrease of hydraulic permeability and decrease of GAG release. The least promising candidate exhibited the opposite behaviour. The study shows the potential of a novel drug evaluation platform in identifying treatments that might reduce cartilage degradation. It also demonstrates the promise of exhaustive combination experiments and a connection between chondrocyte responses at the molecular level with changes of biomechanical properties at the tissue level.

Recent advance in treatment of osteoarthritis by bioactive components from herbal medicine

Osteoarthritis (OA) is a common chronic articular degenerative disease, and characterized by articular cartilage degradation, synovial inflammation/immunity, and subchondral bone lesion, etc. The disease affects 2-6% of the population around the world, and its prevalence rises with age and exceeds 40% in people over 70. Recently, increasing interest has been devoted to the treatment or prevention of OA by herbal medicines. In this paper, the herbal compounds with anti-OA activities were reviewed, and the cheminformatics tools were used to predict their drug-likeness properties and pharmacokinetic parameters. A total of 43 herbal compounds were analyzed, which mainly target the damaged joints (e.g. cartilage, subchondral bone, and synovium, etc.) and circulatory system to improve the pathogenesis of OA. Through cheminformatics analysis, over half of these compounds have good drug-likeness properties, and the pharmacokinetic behavior of these components still needs to be further optimized, which is conducive to the enhancement in their drug-likeness properties. Most of the compounds can be an alternative and valuable source for anti-OA drug discovery, which may be worthy of further investigation and development.

Anti-Inflammatory and Chondroprotective Effects of Vanillic Acid and Epimedin C in Human Osteoarthritic Chondrocytes

In osteoarthritis (OA), inhibition of excessively expressed pro-inflammatory cytokines in the OA joint and increasing the anabolism for cartilage regeneration are necessary. In this ex-vivo study, we used an inflammatory model of human OA chondrocytes microtissues, consisting of treatment with cytokines (interleukin 1β (IL-1β)/tumor necrosis factor α (TNF-α)) with or without supplementation of six herbal compounds with previously identified chondroprotective effect. The compounds were assessed for their capacity to modulate the key catabolic and anabolic factors using several molecular analyses. We selectively investigated the mechanism of action of the two most potent compounds Vanillic acid (VA) and Epimedin C (Epi C). After identification of the anti-inflammatory and anabolic properties of VA and Epi C, the Ingenuity Pathway Analysis showed that in both treatment groups, osteoarthritic signaling pathways were inhibited. In the treatment group with VA, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling was inhibited by attenuation of the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκBα) phosphorylation. Epi C showed a significant anabolic effect by increasing the expression of collagenous and non-collagenous matrix proteins. In conclusion, VA, through inhibition of phosphorylation in NF-κB signaling pathway and Epi C, by increasing the expression of extracellular matrix components, showed significant anti-inflammatory and anabolic properties and might be potentially used in combination to treat or prevent joint OA.

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.

The Therapeutic Effects of Treadmill Exercise on Osteoarthritis in Rats by Inhibiting the HDAC3/NF-KappaB Pathway in vivo and in vitro

Osteoarthritis (OA) is a disease characterized by non-bacterial inflammation. Histone deacetylase 3 (HDAC3) is a crucial positive regulator in the inflammation that leads to the development of non-OA inflammatory disease. However, the precise involvement of HDAC3 in OA is still unknown, and the underlying mechanism of exercise therapy in OA requires more research. We investigated the involvement of HDAC3 in exercise therapy-treated OA. Expression levels of HDAC3, a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), matrix metalloproteinase-13 (MMP-13), HDAC3 and nuclear factor-kappaB (NF-kappaB) were measured by western blotting, reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. Cartilage damage and OA evaluation were measured by hematoxylin and eosin staining and Toluidine blue O staining according to the Mankin score and OARSI score, respectively. We found that moderate-intensity treadmill exercise could relieve OA. Meanwhile, the expression of HDAC3, MMP-13, ADAMTS-5 and NF-kappaB decreased, and collagen II increased in the OA + moderate-intensity treadmill exercise group (OAM) compared with the OA group (OAG) or OA + high- or low-intensity treadmill exercise groups (OAH or OAL). Furthermore, we found the selective HDAC3 inhibitor RGFP966 could also alleviate inflammation in OA rat model through inhibition of nuclear translocation of NF-kappaB. To further explore the relationship between HDAC3 and NF-kappaB, we investigated the change of NF-kappaB relocation in IL-1β-treated chondrocytes under the stimulation of RGFP966. We found that RGFP966 could inhibit the expression of inflammatory markers of OA via regulation of HDAC3/NF-kappaB pathway. These investigations revealed that RGFP966 is therefore a promising new drug for treating OA.

MiR-146b accelerates osteoarthritis progression by targeting alpha-2-macroglobulin

Osteoarthritis (OA) is an aging-related chronic degenerative disease characterized by the degradation of chondrocyte extracellular matrix (ECM). Previous studies have suggested that microRNAs (miRNAs) are associated with OA, but the role of miR-146b in OA remains unclear. The aim of this study was to determine the role of miR-146b in OA progression. The effect of miR-146b on ECM degradation were studied in mouse chondrocytes transfected with miRNA and treated with IL-1β. Cell viability and the expression levels of proteolytic enzymes in the transfected cells were assessed by real-time RT-PCR, ELISA and Western blots. We found downregulation of miR-146b expression in chondrocytes dramatically inhibited IL-1β-induced caspase activation and proteolytic enzyme expression via influencing its targeted Alpha-2-macroglobulin (A2M). Luciferase reporter assays confirmed that A2M mRNA was negatively regulated by miR-146b in chondrocytes. Intra-articular injection of antago-miR-146b against miR-146b effectively protected mice from the progression of DMM-induced osteoarthritis by inhibiting cartilage proteoglycan degradation. Our study indicates that miR-146b plays a critical role in the progression of injury-induced osteoarthritis by directly targeting A2M expression to elevate the proteolytic enzyme production and stimulate chondrocytes apoptosis, and miR-146b as well as A2M could be therapeutic targets.

Desumoylation of aggrecan and collagen II facilitates degradation via aggrecanases in IL-1β-mediated osteoarthritis

Background: Aggrecan plays a crucial role in the ability of tissues to withstand compressive loads during the pathological progression of osteoarthritis (OA). Progressive loss of aggrecan from cartilage may result in exposure of the collagen matrix and can lead to its disintegration by metalloproteases. Although aggrecanases are expressed constitutively in human chondrocytes, the degradation of aggrecan is induced by proinflammatory cytokines; however, little is known about the underlying mechanisms. Methods: Human primary chondrocytes from OA patients or healthy donors and human chondrogenic SW1353 cells were cultured and stimulated with IL-1β in vitro, the mRNA expressions and protein levels of MMP-13, ADAMTS-4, ADAMTS-5, SENP1, and SENP2 were determined using real time PCR and Western blot, respectively. The localizations of aggrecan and Col-II, as well as the SUMOylation modification of these proteins were analyzed using immunofluorescence and immunoprecipitation assays, respectively. Results: Our results showed that a proinflammatory cytokine interleukin-1β induced the OA model and desumoylation of aggrecan and collagen type II because the small ubiquitin-like modifier 2/3 (SUMO2/3) was co-localized with aggrecan and collagen type II proteins and interacted physically with them. Mechanistic studies have shown that knockdown of SUMO2/3 expression can significantly enhance the rate of degradation of aggrecan and collagen type II at both the mRNA and protein levels in the OA model. In addition, SUMO-specific protease 2 (SENP2) plays important roles in the desumoylation of aggrecan, while knockdown of SENP2 can protect aggrecan and collagen type II. Clinical assays have shown that OA patients have higher SENP2 levels than healthy controls, and the SENP2 level correlates negatively with both aggrecan and collagen type II levels. Conclusion: SENP2 desumoylates aggrecan and collagen type II proteins in the inflammation induced OA, and SENP2 expression correlates with OA progression.

The potent anti-inflammatory effect of Guilu Erxian Glue extracts remedy joint pain and ameliorate the progression of osteoarthritis in mice

BACKGROUND

Osteoarthritis (OA) is a slow progressing, degenerative disorder of the synovial joints. Guilu Erxian Glue (GEG) is a multi-component Chinese herbal remedy with long-lasting favorable effects on several conditions, including articular pain and muscle strength in elderly men with knee osteoarthritis. The present study aimed to identify the effects of Guilu Erxian Paste (GE-P) and Liquid (GE-L) extracted from Guilu Erxian Glue in anterior cruciate ligament transection (ACLT)-induced osteoarthritis mice, and to compare the effectiveness of different preparations on knee cartilage degeneration during the progression of osteoarthritis.

METHODS

Male C57BL/6J mice underwent anterior cruciate ligament transection to induce mechanically destabilized osteoarthritis in the right knee. 4 weeks later, the mice were orally treated with PBS, celecoxib (10 mg/kg/day), Guilu Erxian Paste (100 or 300 mg/kg/day), and Guilu Erxian Liquid (100 or 300 mg/kg/day) for 28 consecutive days. Von Frey and open-field tests (OFT) were used to evaluate pain behaviors (mechanical hypersensitivity and locomotor performance). Narrowing of the joint space and osteophyte formation were examined radiographically. Inflammatory cytokine (IL-1β, IL-6, and TNF-α) levels in the articular cartilage were determined by quantitative real-time PCR. Histopathological examinations were conducted to evaluate the severity and extent of the cartilage lesions.

RESULTS

Guilu Erxian Paste and Guilu Erxian Liquid (300 mg/kg/day) were significantly more effective (p < 0.01) than celecoxib (10 mg/kg/day) in decreasing secondary allodynia when compared to the saline-treated group (#p < 0.05). Open-field tests revealed no significant motor dysfunction between the Guilu Erxian Paste- and Guilu Erxian Liquid-treated mice compared to the saline-treated mice. Radiographic findings also confirmed that the administration of Guilu Erxian Paste and Guilu Erxian Liquid (100 and 300 mg/kg/day) significantly and dose-dependently reduced osteolytic lesions and bone spur formation in the anterior cruciate ligament transection-induced osteoarthritis mice when compared to the saline-treated group. Notably, Guilu Erxian Liquid (100 mg/kg/day) treatment significantly reduced the mRNA levels of IL-1β, IL-6, and TNF-α as well as relative the protein expression of IL-1β and TNF-α to the effect of celecoxib. Guilu Erxian Paste and Guilu Erxian Liquid (300 mg/kg/day) markedly attenuated cartilage destruction, surface unevenness, proteoglycan loss, chondrocyte degeneration, and cartilage erosion in the superficial layers (##p < 0.01 and ###p < 0.001 respectively).

CONCLUSIONS

As expected, our findings suggest that the anti-inflammatory effects of Guilu Erxian Liquid (GE-L), following marked decrease on both IL-1β and TNF-α during the early course of post-traumatic osteoarthrosis (OA), may be of potential value in the treatment of osteoarthritis.

Fengshi Gutong Capsule Attenuates Osteoarthritis by Inhibiting MAPK, NF-κB, AP-1, and Akt Pathways

Background and purpose: Fengshi Gutong capsule (FSGTC), a traditional herbal formula, has been used clinically in China for the treatment of arthritis. However, the mechanism underlying the therapeutic effects of FSGTC on osteoarthritis (OA) has not been elucidated. The present study investigated the function and mechanisms of FSGTC in rat OA model and interleukin (IL)-1β-stimulated synovial cells. Materials and methods: Rat OA model was established by intra-articular injection containing 4% papain. IL-1β-induced SW982 cells were used as an OA cell model. Safranin-O-Fast green (S-O) and hematoxylin-eosin (HE) stainings were used to observe the changes in cartilage morphology. Enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (qPCR) detected the expression of inflammatory cytokines. In addition, molecular mechanisms were analyzed by Western blot in the OA cell model. Results: FSGTC treatment significantly relieved the degeneration of cartilage and reduced the contents of tumor necrosis factor-α (TNF-α) and IL-6 in the serum in papain-induced OA rats. FSGTC also reduced the protein and mRNA levels of IL-6 and IL-8 in IL-1β-stimulated SW982 cells. Moreover, it inhibited the phosphorylation levels of ERK (extracellular signal-related kinase), JNK (c-Jun N-terminal kinase), p38, Akt (protein kinase B), and c-Jun. It also decreased the extent of IκBα degradation and p65 protein translocation into the nucleus. Conclusion: The current data confirmed the protective effects of FSGTC in the rat and OA cell models. The results suggested that FSGTC reduced the production of inflammatory mediators via restraining the activation of mitogen-activated protein kinases (MAPK), nuclear factor kappa B (NF-κB), activator protein-1 (AP-1), and Akt.