β-Hydroxyisovalerylshikonin inhibits IL-1β-induced chondrocyte inflammation via Nrf2 and retards osteoarthritis in mice

Notopterol alleviates the progression of osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA) is a prevalent degenerative joint disorder caused by the progressive destruction of cartilage and inflammation in the articular cavity. Studies have proved that the inhibition of articular cartilage destruction and generation of inflammatory factors can be effective strategies for treating OA. Notopterol (NOT) is a quality control index of Notopterygium incisum Ting ex H. T. Chang (N. incisum) with anti-inflammatory, antioxidant, and analgesic activities. Moreover, NOT has been used for many years to treat joint diseases. A study using human C28/I2 cells suggested that NOT down-regulated the hypersecretion of inflammatory mediators and alleviated the degradation of the extracellular matrix (ECM). In addition, NOT decreased the overproduction of reactive oxygen species (ROS) and chondrocyte apoptosis through the nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway. NOT exerted a chondroprotective effect by partly inhibiting the Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT3) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways and regulating the nuclear factor Nrf2/heme oxygenase-1(HO-1) signaling pathway. In vivo, NOT improved the destruction of articular cartilage in a rat OA model, which may be related to the inhibition of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6, and IL-12 expressions in synovial fluid. In summary, these results showed that NOT alleviated the progression of OA and is expected to become a new therapy for treating OA clinically.

Hsa_circ_0007292 promotes chondrocyte injury in osteoarthritis via targeting the miR-1179/HMGB1 axis

BACKGROUND

Circular RNAs (circRNAs) have been demonstrated to participate in the progression of osteoarthritis (OA). This study aimed to investigate the role and molecular mechanism of hsa_circ_0007292 in OA.

METHODS

Hsa_circ_0007292 was identified by analyzing a circRNA microarray from the Gene Expression Omnibus (GEO) database, and its expression was detected by real-time PCR in OA cartilage tissues and interleukin (IL)-1β-induced two human chondrocytes (CHON-001 and C28/I2), the OA cell models. The effects of hsa_circ_0007292 knockdown and miR-1179 overexpression on IL-1β-induced chondrocyte injury were examined by CCK-8, BrdU, flow cytometry, ELISA, and western blot. RNA pull-down assay and dual-luciferase reporter gene assay were used to analyze the interaction between hsa_circ_0007292 and miR-1179. Rescue experiments were carried out to determine the correlations among hsa_circ_0007292, miR-1179 and high mobility group box-1 (HMGB1).

RESULTS

Hsa_circ_0007292 expression was upregulated in OA tissues and IL-1β-induced chondrocytes. Both downregulation of hsa_circ_0007292 and miR-1179 overexpression increased the proliferation and Aggrecan expression, suppressed apoptosis, matrix catabolic enzyme MMP13 expression and inflammatory factor (TNF-α, IL-6, and IL-8) levels. There was a negative correlation between hsa_circ_0007292 and miR-1179, and a positive correlation between hsa_circ_0007292 and HMGB1 in OA tissues. The mechanistic study showed that hsa_circ_0007292 prevented HMGB1 downregulation by sponging miR-1179. Upregulation of HMGB1 could reverse the influence of hsa_circ_0007292 downregulation on IL-1β-induced chondrocyte injury.

CONCLUSIONS

Downregulation of hsa_circ_0007292 relieved apoptosis, extracellular matrix degradation and inflammatory response in OA via the miR-1179/HMGB1 axis, suggesting that hsa_circ_0007292 might be a potential therapeutic target for OA treatment.

Phillygenin inhibits inflammation in chondrocytes via the Nrf2/NF-κB axis and ameliorates osteoarthritis in mice

Objective

Osteoarthritis (OA), widely seen in the elderly, is featured by cartilage degradation, subchondral bone remolding, and synovium inflammation. Currently, there is no cure for OA development. Phillygenin (PHI), an active ingredient from the Forsythiae Fructus, possesses many biological properties, such as anti-inflammation and anti-oxidative stress in several diseases. However, the potential effects and underlying mechanisms of PHI on OA remain unclear.

Methods

Western blotting, RT-PCR, ELISA and tissue staining were employed to explore the mechanisms by which PHI exerted a protective effect on IL-1β-induced production of pro-inflammation cytokines and extracellular matrix (ECM) degradation in primary murine chondrocytes and destabilization of the medial meniscus (DMM) mouse models.

Results

In this study, we found that PHI inhibited the production of pro-inflammation cytokines and ECM degradation induced by IL-1β in primary murine chondrocytes. Mechanically, PHI inhibited the NF-κB pathway via activating nuclear factor (erythrluteolind-derived 2)-like 2 (Nrf2). In vivo experiments also confirmed the chondroprotection of PHI in DMM mouse models.

Conclusion

PHI alleviated IL-1β-induced inflammation cytokines and ECM degradation via activating Nrf2 and inhibiting NF-κB pathway.

The translational potential of this article

This study provides a biological rationale for the use of PHI as a potential candidate for OA treatment.

Extracellular matrix in synovium development, homeostasis and arthritis disease

Extracellular matrix (ECM) is a three-dimensional network entity composed of extracellular macromolecules. ECM in synovium not only supports the structural integrity of synovium, but also plays a crucial role in regulating homeostasis and damage repair response in synovium. Obvious disorders in the composition, behavior and function of synovial ECM will lead to the occurrence and development of arthritis diseases such as rheumatoid arthritis (RA), osteoarthritis (OA) and psoriatic arthritis (PsA). Based on the importance of synovial ECM, targeted regulation of the composition and structure of ECM is considered to be an effective measure for the treatment of arthritis disease. This paper reviews the current research status of synovial ECM biology, discusses the role and mechanism of synovial ECM in physiological status and arthritis disease, and summarizes the current strategies for targeting synovial ECM to provide information for the pathogenesis, diagnosis and treatment of arthritis disease.

Oxymatrine ameliorates osteoarthritis via the Nrf2/NF-κB axis in vitro and in vivo

PURPOSE

Osteoarthritis (OA) is a common degenerative joint disorder. Currently, the underlying etiology of OA is still far from fully elucidated and there is no cure for OA progression. Previous studies have demonstrated that oxymatrine (OMT) could inhibit inflammation and oxidative stress in several animal models. However, the potential effects of OMT on OA remain largely elusive. The aim of the study is to investigate the anti-inflammatory and chondrocyte protective effect of OMT, and delineate the potential mechanism in vitro and in vivo.

METHODS

Western blotting, RT-qPCR, ELISA and tissue staining were employed to explore the mechanisms by which OMT exerted a protective effect on IL-1β-induced production of pro-inflammation cytokines and extracellular matrix (ECM) degradation in primary murine chondrocytes and DMM mouse models.

RESULTS

The results showed that OMT reduced the IL-1β-induced over-production of pro-inflammation cytokines and ECM degradation. Mechanistically, OMT inhibited the NF-κB pathway via activating Nrf2. In vivo studies also demonstrated that OMT ameliorated OA progression.

CONCLUSIONS

OMT reduced pro-inflammation cytokines, ECM degradation and OA progression via activating Nrf2 and inhibiting NF-κB pathway.

In vitro wound healing potential of cyclohexane extract of Onosma dichroantha Boiss. based on bioassay-guided fractionation

Onosma dichroantha Boiss. is a biennial herb used in traditional medicine in Iran for healing wounds and burns. Our previous study demonstrated that cyclohexane extract of O. dichroantha Boiss. enhanced wound healing in vitro. The aim of the present study was to identify the active fractions and compounds responsible for this effect through bio-guided fractionation followed by three in vitro tests for anti-inflammation, proliferation, and migration (scratch test). Fractionation of the CE extract yielded six fractions (Fr. A to Fr. F). Fr. F showed the most remarkable wound healing activity in three assays. Fr. F was further fractionated into five subfractions (FF-SUB1 to FF-SUB5). FF-SUB1 and FF-SUB2 were selected for further purification based on their wound healing activity. The major components, F. F1 to F. F5, were isolated from these two subfractions and identified as acetylshikonin, deoxyshikonin, β, β-dimethylacrylshikonin, β-hydroxyisovalerylshikonin, and trans-anethole of the active subfractions. Bioassay-guided fractionation revealed that naphthoquinone derivatives, as an active component, are responsible for the wound healing properties of the fractions and subfractions of cyclohexane extract of O. dichroantha roots. The findings indicate that these fractions and subsections, as well as purified compounds, have a high potential for further investigation as an effective therapeutic agent in wound healing using in vivo models.

Research progress on the mechanism of interleukin-1β on epiphyseal plate chondrocytes

Epiphyseal plate injury, a common problem in pediatric orthopedics, may result in poor bone repair or growth defects. Epiphyseal plate, also known as growth plate is a layer of hyaline cartilage tissue between the epiphysis and metaphyseal and has the ability to grow longitudinally. Under normal physiological conditions, the epiphyseal plate has a certain axial resistance to stress, but it is fragile in growth phase and can be damaged by excessive stress, leading to detachment or avulsion of the epiphysis, resulting in life-long devastating consequences for patients. There is an obvious inflammatory response in the phase of growth plate injury, the limited physiological inflammatory response locally favors tissue repair and the organism, but uncontrolled chronic inflammation always leads to tissue destruction and disease progression. Interleukin-1β (IL-1β), as representative inflammatory factors, not only affect the inflammatory phase response to bone and soft tissue injury, but have a potentially important role in the later repair phase, though the exact mechanism is not fully understood. At present, epiphyseal plate injuries are mainly treated by corrective and reconstructive surgery, which is highly invasive with limited effectiveness, thus new therapeutic approaches are urgently needed, so a deeper understanding and exploration of the pathological mechanisms of epiphyseal plate injuries at the cellular molecular level is an entry point. In this review, we fully introduced the key role of IL-1 in the progression of epiphyseal plate injury and repair, deeply explored the mechanism of IL-1 on the molecular transcript level and endocrine metabolism of chondrocytes from multiple aspects, and summarized other possible mechanisms to provide theoretical basis for the clinical treatment and in-depth study of epiphyseal plate injury in children.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

Protective Effects of Ferulic Acid on Deoxynivalenol-Induced Toxicity in IPEC-J2 Cells

Deoxynivalenol (DON), a mycotoxin that contaminates crops such as wheat and corn, can cause severe acute or chronic injury when ingested by animals or humans. This study investigated the protective effect of ferulic acid (FA), a polyphenolic substance, on alleviating the toxicity induced by DON (40 μM) in IPEC-J2 cells. The experiments results showed that FA not only alleviated the decrease in cell viability caused by DON (p < 0.05), but increased the level of superoxide dismutase (SOD) (p < 0.01), glutathione peroxidase (GSH-Px), (catalase) CAT and glutathione (GSH) (p < 0.05) through the nuclear factor erythroid 2-related factor 2 (Nrf2)-epoxy chloropropane Kelch sample related protein-1 (keap1) pathway, and then decreased the levels of intracellular oxidative stress. Additionally, FA could alleviate DON-induced inflammation through mitogen-activated protein kinases (MAPKs) and nuclear factor kappa-B (NF-κB) pathways, down-regulated the secretion of interleukin-6 (IL-6) (p < 0.0001), interleukin-8 (IL-8) (p < 0.05), interleukin-1β (IL-1β), interferon-γ (IFN-γ) and further attenuated the DON-induced intracellular apoptosis (10.7% to 6.84%) by regulating the expression of Bcl2-associated X protein (Bax) (p < 0.0001), B-cell lymphoma-2 (Bcl-2) (p < 0.0001), and caspase-3 (p < 0.0001). All these results indicate that FA exhibits a significantly protective effect against DON-induced toxicity.

Nootkatone protects cartilage against degeneration in mice by inhibiting NF-κB signaling pathway

Osteoarthritis is a common chronic disease associated with chondrocyte inflammation and cartilage matrix hydrolyzation. Studies report that IL-1β plays a critical role in osteoarthritis. Anti-inflammatory effect of nootkatone has been explored in acute and chronic inflammatory disease, thus the current study sought to explore its therapeutic effect in osteoarthritis. Notably, the effect of nootkatone in osteoarthritis has not been elucidated. Therefore, murine primary chondrocytes were extracted and ACLT induced OA mouse model was established in the current study to explore the therapeutic effect of nootkatone in OA both in vitro and in vivo. The findings showed that nootkatone inhibited inflammatory response and protected cartilage balance in murine primary chondrocyte. Further analysis showed that nootkatone suppressed inflammation and protected cartilage against degeneration induced by ACLT surgery in mice. The cellular mechanism of the protective effect of nootkatone in osteoarthritis and associated signaling pathway was identified as the NF-κB signaling pathway. In summary, the findings of the current study indicated that nootkatone is a potential therapeutic agent for OA.

Xanthohumol Attenuated Inflammation and ECM Degradation by Mediating HO-1/C/EBPβ Pathway in Osteoarthritis Chondrocytes

Osteoarthritis (OA) is the most frequent and disabling disease in developed countries. The progressive degeneration of articular cartilage characterized as thinner and erosive. Inflammation is well-known to be involved in OA development. However, there are no effective therapeutic strategies to cure it. Xanthohumol (XH) is a natural prenylflavonoid isolated from hops and beer. The protective activity of XH against OA chondrocytes inflammation and ECM degradation is unclear. In this article, we found that XH significantly inhibited inflammatory responses, attenuated catabolic enzymes expression, and ameliorated ECM degradation, as showed by decreased production of NO, PGE2, TNFα, and IL-6, decreased expression of MMP-3/-13 and ADAMTS-4/-5, and increased expression of collagen-II and aggrecan. In addition, XH activated HO-1 signaling and attenuated IL-1β-induced C/EBPβ. XH promoted the interaction between HO-1 and C/EBPβ, inhibiting the nuclear translocation of C/EBPβ. HO-1 knockdown could abrogate the protective effects of XH in IL-1β-treated chondrocytes. Collectively, XH attenuated inflammatory responses and ECM degradation by mediating HO-1 and C/EBPβ signaling pathways in osteoarthritis chondrocytes.