Chondroprotective role of sesamol by inhibiting MMPs expression via retaining NF-κB signaling in activated SW1353 cells

Sesamol as a potent anticancer compound: from chemistry to cellular interactions

Sesamol (SM), a well-known component isolated from sesame seeds (Sesamum indicum), used in traditional medicines in treating numerous ailments. However, numerous molecular investigations revealed the various mechanisms behind its activity, emphasizing its antiproliferative, anti-inflammatory, and apoptosis-inducing properties, preventing cancer cell spread to distant organs. In several cells derived from various malignant tissues, SM-regulated signal transduction pathways and cellular targets have been identified. This review paper comprehensively describes the anticancer properties of SM and SM-viable anticancer drugs. Additionally, the interactions of this natural substance with standard anticancer drugs are examined, and the benefits of using nanotechnology in SM applications are explored. This makes SM a prime example of how ethnopharmacological knowledge can be applied to the development of contemporary drugs.

Sesamol: A lignan in sesame seeds with potent anti-inflammatory and immunomodulatory properties

Inflammation is associated with the development and progression of a plethora of diseases including joint, metabolic, neurological, hepatic, and renal disorders. Sesamol, derived from the seeds of Sesamum indicum L., has received considerable attention due to its well-documented multipotent phytotherapeutic effects, including its anti-inflammatory and immunomodulatory properties. However, to date, no comprehensive review has been established to highlight or summarize the anti-inflammatory and immunomodulatory properties of sesamol. Herein, we aim to address this gap in the literature by presenting a thorough review encapsulating evidence surrounding the range of inflammatory mediators and cytokines shown to be targeted by sesamol in modulating its anti-inflammatory actions against a range of inflammatory disorders. Additionally, evidence highlighting the role that sesamol has in modulating components of adaptive immunity including cellular immune responses and Th1/Th2 balance is underscored. Moreover, the molecular mechanisms and the signaling pathways underlying such effects are also highlighted. Findings indicate that this seemingly potent lignan mediates its anti-inflammatory actions, at least in part, via suppression of various pro-inflammatory cytokines like IL-1β and TNFα, and downregulation of a multitude of signaling pathways including NF-κB and MAPK. In conclusion, we anticipate that sesamol may be employed in future therapeutic regimens to aid in more effective drug development to alleviate immune-related and inflammatory conditions.

Effects and action mechanisms of individual cytokines contained in PRP on osteoarthritis

Osteoarthritis (OA) is defined as a degenerative joint disease that can affect all tissues of the joint, including the articular cartilage, subchondral bone, ligaments capsule, and synovial membrane. The conventional nonoperative treatments are ineffective for cartilage repair and induce only symptomatic relief. Platelet-rich plasma (PRP) is a platelet concentrate derived from autologous whole blood with a high concentration of platelets, which can exert anti-inflammatory and regenerative effects by releasing multiple growth factors and cytokines. Recent studies have shown that PRP exhibits clinical benefits in patients with OA. However, high operational and equipment requirements greatly limit the application of PRP to OA treatment. Past studies have indicated that high-concentration PRP growth factors and cytokines may be applied as a commercial replacement for PRP. We reviewed the relevant articles to summarize the feasibility and mechanisms of PRP-based growth factors in OA. The available evidence suggests that transforming growth factor-α and β, platelet-derived growth factors, epidermal growth factor, insulin-like growth factor-1, and connective tissue growth factors might benefit OA, while vascular endothelial growth factor, tumor necrosis factor-α, angiopoietin-1, and stromal cell derived factor-1α might induce negative effects on OA. The effects of fibroblast growth factor, hepatocyte growth factor, platelet factor 4, and keratinocyte growth factor on OA remain uncertain. Thus, it can be concluded that not all cytokines released by PRP are beneficial, although the therapeutic action of PRP has a valuable potential to improve.

The protective effects of sesamol and/or the probiotic, Lactobacillus rhamnosus, against aluminum chloride-induced neurotoxicity and hepatotoxicity in rats: Modulation of Wnt/β-catenin/GSK-3β, JAK-2/STAT-3, PPAR-γ, inflammatory, and apoptotic pathways

Introduction: Aluminium (Al) is accumulated in the brain causing neurotoxicity and neurodegenerative disease like Alzheimer's disease (AD), multiple sclerosis, autism and epilepsy. Hence, attenuation of Al-induced neurotoxicity has become a "hot topic" in looking for an intervention that slow down the progression of neurodegenerative diseases. Objective: Our study aims to introduce a new strategy for hampering aluminum chloride (AlCl3)-induced neurotoxicity using a combination of sesamol with the probiotic bacteria; Lactobacillus rhamnosus (L. rhamnosus) and also to test their possible ameliorative effects on AlCl3-induced hepatotoxicity. Methods: Sprague-Dawley male rats were randomly divided into five groups (n = 10/group) which are control, AlCl3, AlCl3 + Sesamol, AlCl3 + L. rhamnosus and AlCl3 + Sesamol + L. rhamnosus. We surveilled the behavioral, biochemical, and histopathological alterations centrally in the brain and peripherally in liver. Results: This work revealed that the combined therapy of sesamol and L. rhamnosus produced marked reduction in brain amyloid-β, p-tau, GSK-3β, inflammatory and apoptotic biomarkers, along with marked elevation in brain free β-catenin and Wnt3a, compared to AlCl3-intoxicated rats. Also, the combined therapy exerted pronounced reduction in hepatic expressions of JAK-2/STAT-3, inflammatory (TNF-α, IL-6, NF-κB), fibrotic (MMP-2, TIMP-1, α-SMA) and apoptotic markers, (caspase-3), together with marked elevation in hepatic PPAR-γ expression, compared to AlCl3 -intoxicated rats. Behavioral and histopathological assessments substantiated the efficiency of this combined regimen in halting the effect of neurotoxicity. Discussion: Probiotics can be used as an add-on therapy with sesamol ameliorate AlCl3 -mediated neurotoxicity and hepatotoxicity.

Bauhinia championii alleviates extracellular matrix degradation in IL-1β induced chondrocytes via miRNA-145-5p/TLR4/NF-κB axis

Bauhinia championii is a herbal medicine used to treat osteoarthritis (OA) in Chinese traditional medicine. However, the molecular mechanisms underlying the therapeutic effects of this medicinal herb against OA have rarely been reported. Given that it has been established that extracellular matrix metabolism plays an important role in the pathogenesis of OA, the present study focused on the effects and mechanisms of Bauhinia championii in the regulation of extracellular matrix metabolism in chondrocytes induced by IL-1β. Rat chondrocytes were isolated, cultured and identified in vitro. The CCK-8 method was used to detect the cell viability of Bauhinia championii aqueous extract (BCAE)-treated chondrocytes. The chondrocyte inflammatory and degeneration models were induced by 10 ng/mL IL-1β, then chondrocytes were grouped into different groups to evaluate the effect of BCAE on extracellular matrix degradation and the regulation of TLR4/NF-κB signaling pathway. Furthermore, whether the regulatory effect of BCAE on TLR4/NF-κB signaling pathway is related to miRNA-145-5p was also investigated by cell transfection. We found that BCAE promoted chondrocyte viability in a dose- and time-dependent manner. BCAE delayed chondrocyte degeneration induced by IL-1β. BCAE could reduce the degradation of the cartilage extracellular matrix by inhibiting the TLR4/NF-κB signaling pathway. miRNA-145-5p negatively regulated the expression of TLR4 in chondrocytes, while BCAE could upregulate the expression of miRNA-145-5p in chondrocytes induced by IL-1β. These results suggest that BCAE upregulates the expression of miRNA-145-5p to inhibit the TLR4/NF-κB signaling pathway, thereby alleviating the metabolic imbalance of the extracellular matrix and protecting chondrocytes from degeneration.

Ubiquitin-specific proteases: Vital regulatory molecules in bone and bone-related diseases

Stabilization of bone structure and function involves multiple cell-to-cell and molecular interactions, in which the regulatory functions of post-translational modifications such as ubiquitination and deubiquitination shouldn't be underestimated. As the largest family of deubiquitinating enzymes, the ubiquitin-specific proteases (USPs) participate in the development of bone homeostasis and bone-related diseases through multiple classical osteogenic and osteolytic signaling pathways, such as BMP/TGF-β pathway, NF-κB/p65 pathway, EGFR-MAPK pathway and Wnt/β-catenin pathway. Meanwhile, USPs may also broadly regulate regulate hormone expression level, cell proliferation and differentiation, and may further influence bone homeostasis from gene fusion and nuclear translocation of transcription factors. The number of patients with bone-related diseases is currently enormous, making exploration of their pathogenesis and targeted therapy a hot topic. Pathological increases in the levels of inflammatory mediators such as IL-1β and TNF-α lead to inflammatory bone diseases such as osteoarthritis, rheumatoid arthritis and periodontitis. While impaired body metabolism greatly increases the probability of osteoporosis. Abnormal physiological activity of bone-associated cells results in a variety of bone tumors. The regulatory role of USPs in bone-related disease has received particular attention from academics in recent studies. In this review, we focuse on the roles and mechanisms of USPs in bone homeostasis and bone-related diseases, with the expectation of informing targeted therapies in the clinic.

The clusterin connectome: Emerging players in chondrocyte biology and putative exploratory biomarkers of osteoarthritis

Introduction

Clusterin is amoonlighting protein that hasmany functions. It is amultifunctional Q6 holdase chaperone glycoprotein that is present intracellularly and extracellularly in almost all bodily fluids. Clusterin is involved in lipid transport, cell differentiation, regulation of apoptosis, and clearance of cellular debris, and plays a protective role in ensuring cellular survival. However, the possible involvement of clusterin in arthritic disease remains unclear. Given the significant potential of clusterin as a biomarker of osteoarthritis (OA), a more detailed analysis of its complex network in an inflammatory environment, specifically in the context of OA, is required. Based on the molecular network of clusterin, this study aimed to identify interacting partners that could be developed into biomarker panels for OA.

Methods

The STRING database and Cytoscape were used to map and visualize the clusterin connectome. The Qiagen Ingenuity Pathway Analysis (IPA) software was used to analyze and study clusterinassociated signaling networks in OA. We also analyzed transcription factors known to modulate clusterin expression, which may be altered in OA.

Results

The top hits in the clusterin network were intracellular chaperones, aggregate-forming proteins, apoptosis regulators and complement proteins. Using a text-mining approach in Cytoscape, we identified additional interacting partners, including serum proteins, apolipoproteins, and heat shock proteins.

Discussion

Based on known interactions with proteins, we predicted potential novel components of the clusterin connectome in OA, including selenoprotein R, semaphorins, and meprins, which may be important for designing new prognostic or diagnostic biomarker panels.

Sesamol Attenuates Neuroinflammation by Regulating the AMPK/SIRT1/NF-κB Signaling Pathway after Spinal Cord Injury in Mice

Inflammation is one of the crucial mechanisms mediating spinal cord injury (SCI) progress. Sesamol, a component of sesame oil, has anti-inflammatory activity, but its mechanism in SCI remains unclear. We investigated if the AMPK/SIRT1/NF-κB pathway participated in anti-inflammation of sesamol in SCI. Sesamol could inhibit neuronal apoptosis, reduce neuroinflammation, enhance M2 phenotype microglial polarization, and improved motor function recovery in mice after SCI. Furthermore, sesamol increased SIRT1 protein expression and p-AMPK/AMPK ratio, while it downregulated the p-p65/p65 ratio, indicating that sesamol treatment upregulated the AMPK/SIRT1 pathway and inhibited NF-κB activation. However, these effects were blocked by compound C which is a specific AMPK inhibitor. Together, the study suggests that sesamol is a potential drug for antineuroinflammation and improving locomotor functional recovery through regulation of the AMPK/SIRT1/NF-κB pathway in SCI.

Effects of Sesame Consumption on Inflammatory Biomarkers in Humans: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objectives

Existing evidence produces conflicting findings regarding the effect of sesame intake on inflammatory biomarkers; this knowledge gap has yet to be met through systematic review and meta-analysis. This meta-analysis of randomized, controlled clinical trials (RCTs) was conducted to evaluate the effects of sesame consumption on markers of inflammation in humans.

Methods

PubMed, Scopus, and the Cochrane Database of Systematic Reviews were searched through August 2020 to identify relevant papers for inclusion. Using the random-effects model, data were evaluated as weighted mean differences (WMD) with 95% confidence intervals (CI). Cochrane's Q and I-squared (I²) tests were used to identify within-studies heterogeneity.

Results

Seven RCTs with 310 participants (157 intervention and 153 control) were included in the meta-analysis. Sesame consumption reduced serum level interleukin-6 (IL-6) (WMD − 0.90; 95% CI (−1.71, −0.09), I² = 80.4%) compared to the control group. However, sesame intake had no significant effects on C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) compared to the control group. Subgroup analysis identified a reduction in serum CRP, TNF-α, and IL-6 concentration among studies with participants who had a higher level of these biomarkers at baseline, those which used sesamin capsules, and those with a bigger sample size, those conducted in Asia, and studies on females.

Conclusion

Sesame consumption reduced serum levels of IL-6 but did not affect CRP and TNF-α in humans. Additional trials should be conducted utilizing a larger and longer treatment duration, along with studies using different sesame formulations (capsule, oil, and seed) and conducting on participants with varied health conditions.

Sesamol Epigenetically Induces Estrogen Receptor α Re-expression by Upregulating miR-370-3p in Estrogen Receptor α-Negative Breast Cancer

Due to lack of estrogen receptor α (ERα, gene name: ESR1), ERα-negative breast carcinoma is insensitive to endocrine therapy, and restoration of ERα has become a promising strategy for ERα-negative breast cancer treatment. Sesamol, a naturally occurring phenolic compound, is usually extracted from sesame seeds. Previous investigations have unmasked its anti-oxidant and anti-inflammation properties. In this study, sesamol induced ERα functional re-expression followed by upregulation of its downstream pS2 and GREB1 genes in ERα-negative breast carcinoma. Moreover, it endowed responsiveness of ERα-negative breast carcinoma to the endocrine treatment drug 4-hydroxytamoxifen without influencing the viability of normal human umbilical vein endothelial cells. Mechanistically, sesamol induced ESR1 gene promoter demethylation by downregulating the expression of the DNA methyltransferases DNMT3A and DNMT3B, without affecting DNMT1. Moreover, the non-coding RNA miR-370-3p directly targeted DNMT3A and DNMT3B mRNA, and its expression increased upon treatment with sesamol. Artificial abrogation of miR-370-3p expression with an antagomir abolished the inhibition of DNMT3A and DNMT3B expression by sesamol, resulting in a fallback in ERα reactivation. In mice, sesamol significantly induced ERα re-expression via miR-370-3p-mediated downregulation of DNMT3A and DNMT3B. Sesamol may be a safe and effective option for clinical adjuvant therapy in patients with ERα-negative breast cancer.

A low proportion n-6/n-3 PUFA diet supplemented with Antarctic krill (Euphausia superba) oil protects against osteoarthritis by attenuating inflammation in ovariectomized mice

Osteoarthritis (OA), the most common form of arthritis, is characterized by cartilage destruction, and its incidence is much higher in the osteoporotic population. There is increasing evidence that the occurrence and development of OA are modulated by the dietary intake of polyunsaturated fatty acids (PUFA). This study investigated the effects of dietary PUFA, including n-3/n-6 PUFA proportion and the molecular form of n-3 PUFA, on OA using osteoporotic osteoarthritis dual model mice, where phospholipid type n-3 PUFA were specifically examined. The results revealed that a low proportion of n-6/n-3 PUFA in diets from 1 : 1 to 6 : 1 significantly improved the cartilage structure and inhibited articular cartilage polysaccharide loss. Furthermore, the low proportion n-6/n-3 PUFA diets inhibited the NF-κB signaling pathway by activating G-protein coupled receptor 120 (GPR120) to reduce inflammation and inhibit catabolism. Antarctic krill (Euphausia superba) oil (AKO), rich in phospholipid-type n-3 PUFA, had a better effect on OA than linseed oil (plant-derived n-3 PUFA), which may be due to peroxisome proliferator-activated receptor-gamma (PPAR γ). These findings suggested that the low proportion n-6/n-3 PUFA diets, particularly with AKO, alleviated inflammation and inhibited articular cartilage degeneration. Therefore, dietary intervention can be a potential treatment for OA.

Establishing SW1353 Chondrocytes as a Cellular Model of Chondrolysis

Osteoarthritis (OA) is the most common degenerative joint disease characterised by chondrocyte cell death. An in vitro model of chondrocyte cell death may facilitate drug discovery in OA management. In this study, the cytotoxicity and mode of cell death of SW1353 chondrocytes treated with 24 h of OA inducers, including interleukin-1β (IL-1β), hydrogen peroxide (H2O2) and monosodium iodoacetate (MIA), were investigated. The microscopic features, oxidative (isoprostane) and inflammatory markers (tumour necrosis factor-alpha; TNF-α) for control and treated cells were compared. Our results showed that 24 h of H2O2 and MIA caused oxidative stress and a concentration-dependent reduction of SW1353 cell viability without TNF-α level upregulation. H2O2 primarily induced chondrocyte apoptosis with the detection of blebbing formation, cell shrinkage and cellular debris. MIA induced S-phase arrest on chondrocytes with a reduced number of attached cells but without significant cell death. On the other hand, 24 h of IL-1β did not affect the cell morphology and viability of SW1353 cells, with a significant increase in intracellular TNF-α levels without inducing oxidative stress. In conclusion, each OA inducer exerts differential effects on SW1353 chondrocyte cell fate. IL-1β is suitable in the inflammatory study but not for chondrocyte cell death. H2O2 and MIA are suitable for inducing chondrocyte cell death and growth arrest, respectively.

Molecular Targets of Natural Products for Chondroprotection in Destructive Joint Diseases

Osteoarthritis (OA) is the most common type of arthritis that occurs in an aged population. It affects any joints in the body and degenerates the articular cartilage and the subchondral bone. Despite the pathophysiology of OA being different, cartilage resorption is still a symbol of osteoarthritis. Matrix metalloproteinases (MMPs) are important proteolytic enzymes that degrade extra-cellular matrix proteins (ECM) in the body. MMPs contribute to the turnover of cartilage and its break down; their levels have increased in the joint tissues of OA patients. Application of chondroprotective drugs neutralize the activities of MMPs. Natural products derived from herbs and plants developed as traditional medicine have been paid attention to, due to their potential biological effects. The therapeutic value of natural products in OA has increased in reputation due to their clinical impact and insignificant side effects. Several MMPs inhibitor have been used as therapeutic drugs, for a long time. Recently, different types of compounds were reviewed for their biological activities. In this review, we summarize numerous natural products for the development of MMPs inhibitors in arthritic diseases and describe the major signaling targets that were involved for the treatments of these destructive joint diseases.

Esculentoside A protects against osteoarthritis by ameliorating inflammation and repressing osteoclastogenesis

Osteoarthritis is a relatively common disorder of articular deterioration related to cartilage damage, subchondral bone remodelling, inflammation and metabolism. Agents that can inhibit cartilage degradation and osteoclastogenesis are required for the prevention and treatment of osteoarthritis. Esculentoside A, the highest concentration triterpene saponin isolated from the root of Phytolacca esculenta, has commonly been used for the treatment of chronic bronchitis. However, the role esculentoside A plays in ameliorating osteoarthritis has not been reported. We found that esculentoside A suppresses the expression of IL-1β-induced inflammatory and metabolic factors (IL-6, IL-8, TNF-α, MMP2, MMP3 and MMP13). In addition, esculentoside A restrains osteoclast formation by inhibiting the marker gene expression of NFATc1 and c-Fos. Our results indicate that esculentoside A markedly suppresses IL-1β-induced NF-κB and MAPK signalling pathway activation in chondrocytes, and inhibits RANKL-induced osteoclast precursor generation. Finally, treatment with esculentoside A inhibits the progressive cartilage degeneration and osteoclastogenesis in osteoarthritis mouse models. In summary, these results demonstrate that esculentoside A could be a latent therapeutic reagent for the treatment of osteoarthritis.

Recombinant human irisin regulated collagen II, matrix metalloproteinase-13 and the Wnt/β-catenin and NF-κB signaling pathways in interleukin-1β-induced human SW1353 cells

Osteoarthritis (OA) is a degenerative joint disease that seriously affects the quality of life of patients. Irisin has been reported to regulate bone metabolism via the cellular autocrine mechanism and play a protective role in rat OA. In the present study, a SW1353 chondrosarcoma cell line was treated with interleukin (IL)-1β and irisin. The present study evaluated cell viability, expression levels of collagen II (Col II) and matrix metalloproteinase-13 (MMP-13), and activity of the Wnt/β-catenin and NF-κB signaling pathways in treated SW1353 cells. The present results suggested that IL-1β could decrease Col II expression and increase MMP-13 expression at both the mRNA and protein levels, and also activate the Wnt/β-catenin and NF-κB signaling pathways in SW1353 cells. By contrast, irisin was identified to reverse the effects of IL-1β in IL-1β-induced SW1353 cells. The present results suggested that irisin treatment may have a cartilage-protective role in an IL-1β-induced SW1353 cell model.

Anti-Inflammatory and Anticancer Properties of Bioactive Compounds from Sesamum indicum L.-A Review

The use of foodstuff as natural medicines has already been established through studies demonstrating the pharmacological activities that they exhibit. Knowing the nutritional and pharmacological significance of foods enables the understanding of their role against several diseases. Among the foods that can potentially be considered as medicine, is sesame or Sesamum indicum L., which is part of the Pedaliaceae family and is composed of its lignans such as sesamin, sesamol, sesaminol and sesamolin. Its lignans have been widely studied and are known to possess antiaging, anticancer, antidiabetes, anti-inflammatory and antioxidant properties. Modern chronic diseases, which can transform into clinical diseases, are potential targets of these lignans. The prime example of chronic diseases is rheumatic inflammatory diseases, which affect the support structures and the organs of the body and can also develop into malignancies. In line with this, studies emphasizing the anti-inflammatory and anticancer activities of sesame have been discussed in this review.

Sesamol, a major lignan in sesame seeds (Sesamum indicum): Anti-cancer properties and mechanisms of action

Sesamol is a natural phenolic compound and a major lignan isolated from sesame seeds (Sesamum indicum) and sesame oil. The therapeutic potential of sesamol was investigated intensively, and there is compelling evidence that sesamol acts as a metabolic regulator that possesses antioxidant, anti-mutagenic, anti-hepatotoxic, anti-inflammatory, anti-aging, and chemopreventive properties. Various studies have reported that sesamol exerts potent anti-cancer effects. Herein, we provide a comprehensive review that summarizes the in vitro and in vivo anti-cancer activity of sesamol in several cancer cell lines and animal models. The protective role that sesamol plays against oxidative stress through its radical scavenging ability and lipid peroxidation lowering potential is analyzed. The ability of sesamol to regulate apoptosis and various stages of the cell cycle is also outlined. Moreover, the signaling pathways that sesamol seems to target to execute its antioxidant, anti-inflammatory, and pro-apoptotic/anti-proliferative roles are discussed. The signaling pathways that sesamol targets include the p53, MAPK, JNK, PI3K/AKT, TNFα, NF-κB, PPARγ, caspase-3, Nrf2, eNOS, and LOX pathways. The mechanisms of action that sesamol executes to deliver its anti-cancer effects are delineated. In sum, there is ample evidence suggesting that sesamol possesses potent anti-cancer properties in vitro and in vivo. A thorough understanding of the molecular targets of sesamol and the mechanisms of action underlying its anti-cancer effects is necessary for possible employment of sesamol as a chemotherapeutic agent in cancer prevention and therapy.

Ubiquitin-specific protease 3 targets TRAF6 for deubiquitination and suppresses IL-1β induced chondrocyte apoptosis

Traditionally, the development of osteoarthritis (OA) is associated with factors such as aging and injure, but more and more epidemiological and biological evidence suggests that the disease is closely related to metabolic syndrome and metabolic components. Ubiquitin-specific protease 3(USP3), a member of the USPs family, is a specific protease capable of cleavage of ubiquitin chains linked by proline residues. In our presented study, we firstly found that USP3 expression level was decreased in OA. USP3 overexpression inhibited IL-1β induced chondrocytes apoptosis and nuclear factor κB (NF-κB) activation. USP3 knockdown induced chondrocytes apoptosis and activated NF-κB pathway. USP3 interacts with TRAF6 (tumor necrosis factor-receptor-associated factor 6), which is an essential adaptor protein for the NF-κB (nuclear factor κB) signaling pathway and plays important roles in inflammation and immune response. IL-1β treatment up-regulated the polyubiquitination of TRAF6 in chondrocytes, which was attenuated when USP3 was forced expression. Our study mechanistically links USP3 to TRAF6 in osteoarthritis development. Moreover, these data support the pursuit of USP3 and TRAF6 as potential targets for osteoarthritis therapies.

Pro-inflammatory cytokines: The link between obesity and osteoarthritis

Osteoarthritis (OA), characterized by joint malfunction and chronic disability, is the most common form of arthritis. Clinical and animal experiments reveal that age-related OA is associated with many factors such as age, sex, trauma, and obesity. One of the most influential and modifiable risk factors is obesity. Obesity not only increases mechanical stress on the tibiofemoral cartilage, but also leads to a higher prevalence of OA in non-weight-bearing areas. There is a link between obesity and inflammation. Adipose tissues play a crucial role in this context because they are the major source of cytokines, chemokines, and metabolically-active mediators named adipokines. The adipokines, including adiponectin and leptin, have been demonstrated to regulate inflammatory immune responses in cartilage. Obese people and animals show a higher level of serum tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL)-1β and IL-6, all of which are produced by macrophages derived from adipose tissue. These pro-inflammatory cytokines regulate the proliferation and apoptosis of adipocytes, promote lipolysis, inhibit lipid synthesis and decrease blood lipids through autocrine and paracrine mechanisms. Elevated levels of TNF-α, IL-1 and IL-6 have been found in the synovial fluid, synovial membrane, subchondral bone and cartilage of OA patients, confirming their important roles in OA pathogenesis. TNF-α, IL-6 and IL-1 are the factors released by fat to negatively regulate cartilage directly. Moreover, TNF-α, IL-1 and IL-6 can induce the production of other cytokines, matrix metalloproteinases (MMPs) and prostaglandins and inhibit the synthesis of proteoglycans and type II collagen; thus, they play a pivotal role in cartilage matrix degradation and bone resorption in OA. Activated chondrocytes also produce MMP-1, MMP-3, MMP-13, and aggrecanase 1 and 2 (ADAMTS-4, ADAMTS-5). In addition, IL-1, TNF-α and IL-6 may cause OA indirectly by regulating release of adiponectin and leptin from adipocytes. In this review, we first summarize the relationship between obesity and inflammation. Then we summarize the roles of IL-1, TNF-α and IL-6 in OA. We further discuss how IL-1, TNF-α and IL-6 regulate the communication between fat and OA, and their pathological roles in obesity-related OA. Lastly, we discuss the possibility of using the pro-inflammatory signaling pathway as a therapeutic target to develop drugs for obesity-related OA.

Inhibitory effects on the production of inflammatory mediators and reactive oxygen species by Mori folium in lipopolysaccharide-stimulated macrophages and zebrafish

Mori folium, the leaf of Morus alba L. (Moraceae), has been traditionally used for various medicinal purposes from ancient times to the present. In this study, we examined the effects of water extract of Mori folium (WEMF) on the production of inflammatory mediators, such as nitric oxide (NO) and prostaglandin E2 (PGE2), and reactive oxygen species (ROS) in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages. Our data indicated that WEMF significantly suppressed the secretion of NO and PGE2 in RAW 264.7 macrophages without any significant cytotoxicity. The protective effects were accompanied by a marked reduction in their regulatory gene expression at the transcription level. WEMF attenuated LPS-induced intracellular ROS production in RAW 264.7 macrophages. It inhibited the nuclear translocation of the nuclear factor-kappa B p65 subunit and the activation of mitogen-activated protein kinases in LPS-treated RAW 264.7 macrophages. Furthermore, WEMF reduced LPS-induced NO production and ROS accumulation in zebrafish. Although more efforts are needed to fully understand the critical role of WEMF in the inhibition of inflammation, the findings of the present study may provide insights into the approaches for Mori folium as a potential therapeutic agent for inflammatory and antioxidant disorders.

Spermidine Protects against Oxidative Stress in Inflammation Models Using Macrophages and Zebrafish

Spermidine is a naturally occurring polyamine compound that has recently emerged with anti-aging properties and suppresses inflammation and oxidation. However, its mechanisms of action on anti-inflammatory and antioxidant effects have not been fully elucidated. In this study, the potential of spermidine for reducing pro-inflammatory and oxidative effects in lipopolysaccharide (LPS)-stimulated macrophages and zebrafish was explored. Our data indicate that spermidine significantly inhibited the production of pro-inflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), and cytokines including tumor necrosis factor-α and interleukin-1β in RAW 264.7 macrophages without any significant cytotoxicity. The protective effects of spermidine accompanied by a marked suppression in their regulatory gene expression at the transcription levels. Spermidine also attenuated the nuclear translocation of NF-κB p65 subunit and reduced LPS-induced intracellular accumulation of reactive oxygen species (ROS) in RAW 264.7 macrophages. Moreover, spermidine prevented the LPS-induced NO production and ROS accumulation in zebrafish larvae and was found to be associated with a diminished recruitment of neutrophils and macrophages. Although more work is needed to fully understand the critical role of spermidine on the inhibition of inflammation-associated migration of immune cells, our findings clearly demonstrate that spermidine may be a potential therapeutic intervention for the treatment of inflammatory and oxidative disorders.

Minor Constituents in Rice Bran Oil and Sesame Oil Play a Significant Role in Modulating Lipid Homeostasis and Inflammatory Markers in Rats

The effects of feeding rats with groundnut oil (GNO), rice bran oil (RBO), and sesame oil (SESO) on serum lipids, liver lipids, and inflammatory markers were evaluated in rats. Male Wistar rats were fed with AIN-93 diet supplemented with 10 wt% of GNO, RBO, and SESO in the form of native (N) and minor constituent-removed (MCR) oils. Rats given RBO and SESO showed significant reduction in serum and liver lipids, 8-hydroxy-2-deoxyguanosine, cytokines in liver, and eicosanoids in leukocytes as compared with the rats given GNO and MCR oils. The rats fed with native oils of RBO and SESO showed an upregulation of sterol regulatory element-binding protein (SREBP)-2 and peroxisome proliferator-activated receptor gamma (PPARγ) and downregulation of nuclear factor-kappa B (NF-κB) p65. These effects of native oil were significantly compromised when rats were given MCR oils. In conclusion, the minor constituents significantly support the hypolipidemic and anti-inflammatory properties of RBO and SESO.

Role of autophagy in the progression of osteoarthritis: The autophagy inhibitor, 3-methyladenine, aggravates the severity of experimental osteoarthritis

Accumulating evidence suggests that autophagy is closely related to the pathogenesis of osteoarthritis (OA). The aim of this study was to determine the changes in autophagy during the progression of OA and to elucidate the specific role of autophagy in OA. For this purpose, a cellular model of OA was generated by stimulating SW1353 cells with interleukin (IL)-1β and a rabbit model of OA was also established by an intra-articular injection of collagenase, followed by treatment with the autophagy specific inhibitor, 3-methyladenine (3-MA). Cell viability was analyzed by MTS assay, and the mRNA expression levels of matrix metalloproteinases (MMP)-13 and tissue inhibitor of metalloproteinase (TIMP)-1 were determined by RT-qPCR. Cartilage degeneration was examined under a light microscope, and autophagosome and chondrocyte degeneration was observed by transmission electron microscopy. The protein expression of Beclin-1 and light chain 3 (LC3)B was evaluated by western blot analysis and immunofluorescence staining. We found that the autophagy was enhanced during the early stages and was weakened during the late stages of experimental OA. The inhibition of autophagy by 3-MA significantly aggravated the degeneration of chondrocytes and cartilage in experimental OA. Our results thus determine the changes in autophagy during different stages of OA, as well as the role of impaired autophagy in the development of OA. Our data suggest that the regulation of autophagy may be a potential therapeutic strategy with which to attenuate OA.

Intermittent Cyclic Mechanical Tension Promotes Degeneration of Endplate Cartilage via the Nuclear Factor-κB Signaling Pathway: an in Vivo Study

OBJECTIVE

To establish a rabbit model for investigating the effects of intermittent cyclic mechanical tension (ICMT) on promoting degeneration of endplate cartilage.

METHODS

Forty New Zealand white rabbits were subjected to surgery and randomly divided into three equal groups as follows: control group (no treatment, n = 10), sham group (animals underwent a sham operation but were not subjected to mechanical tensile strain, n = 15) and loaded group (discs were subjected to 1.5 MPa external tensile loading by using an external loading device during the animals' daily activity, n = 15). Mechanical tensile strain was applied for 8 h/d. The animals were examined radiologically after 8 weeks treatment and then killed for removal of endplate cartilage tissue samples from their spines. Histological staining was performed to examine the morphology of endplate cartilage tissue. Multiple strategies were employed to examine degeneration of endplate cartilage and nuclear factor (NF)-κB signaling pathway activation.

RESULTS

After ICMT loading for 56 days, radiology revealed ossification, hyperosteogeny and stenosis in the intervertebral spaces. Examination of hematoxylin and eosin staining of sections of endplate cartilage showed significant damage as the load duration increased in the ICMT loading group. Expression of aggrecan (ACAN), type II collagen (COL-2A), SRY-related high mobility group-box gene 9 (SOX9) was down-regulated (FACAN = 21.515, P < 0.01; FCOL-2A = 6.670, P = 0.05; FSOX9 = 7.888, P < 0.05), whereas that of matrix metallopeptidase 13 (MMP13) was up-regulated (FMMP13 = 14.120, P < 0.01) after ICMT. Western blot and immunofluorescence revealed that expression of protein was consistent with gene expression results. Additionally, ICMT loading can lead to NF-κB signaling pathway activation as well as degeneration of endplate cartilage.

CONCLUSION

These experiments indicate that ICMT contributes to the activation of NF-κB signaling pathway in vivo and that the NF-κB signaling pathway further up-regulates MMP13, leading to degeneration of endplate cartilage.

Carbon nanotubes stimulate synovial inflammation by inducing systemic pro-inflammatory cytokines

Carbon nanotubes (CNTs) have promising applications in a wide range of biomedical fields, including imaging, drug/gene delivery and other therapeutics; however, the biosafety concerns of CNTs should be addressed. To date, many reports have documented the toxicological effects on the cells, tissue or organs that are in direct contact with the tubes; however, there is limited evidence to unravel the secondary toxicity upon CNT treatment. Moreover, more effort is needed to gain a definitive understanding of the adverse outcome pathway (AOP) for CNTs, and a pragmatic framework for risk assessment has not been established yet. In the current study, we aimed to decipher the secondary toxicity to joints under CNT exposure. We demonstrated that carboxylated multi-wall CNTs (MWCNTs-COOH) significantly provoked systemic pro-inflammatory responses, leading to synovial inflammation within knee joints, as evidenced by the infiltration of pro-inflammatory cells in the synovium and meniscus. Mechanistic studies showed that MWCNTs-COOH stimulated pro-inflammatory effects by activating macrophages, and the secreted pro-inflammatory cytokines primed the synoviocytes and chondrocytes, resulting in enhanced production of a large array of enzymes involved in articular cartilage degeneration, including matrix metalloproteinase (MMP) members and cyclooxygenase (COX) members, and increased enzymatic activity of MMPs was demonstrated. Blockade of the cytokines by antibodies significantly attenuated the production of these enzymes. Our current study thus suggests that there is a novel secondary toxicity of CNTs, namely a new AOP to understand the indirect effects of carbon nanotubes: synovial inflammation due to the alteration of the priming state of synoviocytes and chondrocytes under CNT-induced systemic inflammatory conditions.

Mori folium inhibits interleukin-1β-induced expression of matrix metalloproteinases and inflammatory mediators by suppressing the activation of NF-κB and p38 MAPK in SW1353 human chondrocytes

The pro-inflammatory cytokine interleukin-1β (IL-1β) is known to play a crucial role in the pathogenesis of osteoarthritis (OA) by stimulating several mediators that contribute to cartilage degradation. Mori folium, the leaves of Morus alba L., has long been used in traditional medicine to treat diabetes, protect the liver, and lower blood pressure; however, the role of Mori folium in OA is not yet fully understood. Therefore, in the present study, we investigated whether Mori folium water extract (MF) inhibited the catabolic effects of IL-1β in vitro, and also whether it inhibited the matrix metalloproteinases (MMPs), inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) through the attenuation of nuclear factor-κB (NF-κB) and mitogen activated protein kinase (MAPK) pathways in SW1353 human chondrocytes. MMP proteins in culture medium were determined using a cytokine‑specific enzyme-linked immunosorbent assay (ELISA). The production of NO and prostaglandin E2 (PGE2) were evaluated using Griess reagent and ELISA. Subsequently, the mRNA and protein levels of MMPs, iNOS, COX-2, NF-κB and MAPKs were examined by RT-qPCR and/or western blot analysis. The results indicate that MF significantly reduced the IL-1β‑induced release of MMP-1 and -13 in SW1353 cells, which was associated with the inhibition of MMP-1 and -13 mRNA and protein expression in a concentration‑dependent manner at concentrations with no cytotoxicity. MF also attenuated the IL-1β-induced production of NO and PGE2, and reduced iNOS and COX-2 expression. Furthermore, we noted that MF markedly suppressed the IL-1β‑induced nuclear translocation of NF-κB, which correlated with the inhibitory effects of MF on inhibitor-κB (IκB) degradation, and the phosphorylation of p38 MAPK was selectively restored by MF upon IL-1β stimulation. These results indicate that MF inhibited the production and expression of MMP-1 and -13 and inflammatory mediators, at least in part, through suppressing the activation of either NF-κB or p38 MAPK in IL-1β-treated SW1353 chondrocytes. Therefore, the novel findings of the present study suggest that MF is a potential therapeutic choice for chondroprotection against the collagen matrix breakdown in the cartilage of diseased tissues, such as those found in patients with arthritic disorders.

Hinokitiol Exerts Anticancer Activity through Downregulation of MMPs 9/2 and Enhancement of Catalase and SOD Enzymes: In Vivo Augmentation of Lung Histoarchitecture

Melanoma is extremely resistant to chemotherapy and the death rate is increasing hastily worldwide. Extracellular matrix promotes the migration and invasion of tumor cells through the production of matrix metalloproteinase (MMP)-2 and -9. Evidence has shown that natural dietary antioxidants are capable of inhibiting cancer cell growth. Our recent studies showed that hinokitiol, a natural bioactive compound, inhibited vascular smooth muscle cell proliferation and platelets aggregation. The present study is to investigate the anticancer efficacy of hinokitiol against B16-F10 melanoma cells via modulating tumor invasion factors MMPs, antioxidant enzymes in vitro. An in vivo mice model of histological investigation was performed to study the patterns of elastic and collagen fibers. Hinokitiol inhibited the expression and activity of MMPs-2 and -9 in B16-F10 melanoma cells, as measured by western blotting and gelatin zymography, respectively. An observed increase in protein expression of MMPs 2/9 in melanoma cells was significantly inhibited by hinokitiol. Notably, hinokitiol (1–5 μM) increased the activities of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) from the reduction in melanoma cells. Also, hinokitiol (2–10 µM) concentration dependently reduced in vitro Fenton reaction induced hydroxyl radical (OH·) formation. An in vivo study showed that hinokitiol treatment increased elastic fibers (EF), collagens dispersion, and improved alveolar alterations in the lungs of B16/F10 injected mice. Overall, our findings propose that hinokitiol may be a potent anticancer candidate through down regulation of MMPs 9/2, reduction of OH· production and enhancement of antioxidant enzymes SOD and CAT.

Sesamol induces apoptosis in human platelets via reactive oxygen species-mediated mitochondrial damage

Platelets play an indispensable role in human health and disease. Platelets are very sensitive to oxidative stress, as it leads to the damage of mitochondrial DNA, which is the initial step of a sequence of events culminating in the cell death through the intrinsic pathway of apoptosis. Owing to a lot of reports on secondary complications arising from oxidative stress caused by therapeutic drug overdose, the present study concentrated on the influence of sesamol on oxidative stress-induced platelet apoptosis. Sesamol, a phenolic derivative present in sesame seeds is an exceptionally promising drug with lots of reports on its protective functions, including its inhibitory effects on platelet aggregation at concentrations below 100 μM, and its anti-cancer effect at 1 mM. However, the present study explored the toxic effects of sesamol on human platelets. Sesamol at the concentration of 0.25 mM and above induced platelet apoptosis through endogenous generation of ROS, depletion of thiol pool, and Ca(2+) mobilization. It also induced mitochondrial membrane potential depolarization, caspase activation, cytochrome c translocation and phosphatidylserine exposure, thus illustrating the pro-apoptotic effect of sesamol at higher concentration. However, even at high concentration of 2 mM sesamol effectively inhibited collagen/ADP/epinephrine-induced platelet aggregation. The study demonstrates that even though sesamol inhibits platelet aggregation, it has the tendency to elicit platelet apoptosis at higher concentrations. Sesamol has a potential as thrombolytic agent, nevertheless the current work highlights the significance of an appropriate dosage of sesamol when it is used as a therapeutic drug.

Inhibitory effect of midazolam on MMP-9, MMP-1 and MMP-13 expression in PMA-stimulated human chondrocytes via recovery of NF-κB signaling

INTRODUCTION

Midazolam, a benzodiazepine, has a hypnotic effect and is widely used as an intravenous sedative. Past studies have clearly established that midazolam has beneficial effects in attenuating ischemia-reperfusion injury more than other currently used sedative drugs. However, the role of midazolam on chondroprotection via inhibition of matrix metalloproteinases (MMPs) is warrant investigation. The aim of this study was to examine the mechanisms of action of midazolam on MMP expression via nuclear factor κB (NF-κB) signaling in activated chondrosarcoma cells maintained in vitro.

MATERIAL AND METHODS

Chondrocytes, SW1353 cells, were stimulated with phorbol 12-myristate 13-acetate (PMA) in the absence or presence of various concentrations of midazolam (5-20 µM). Release of MMP-9 into the culture media was determined by gelatin zymography. The expressions of MMP-1, MMP-9 and MMP-13, phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinases and degradation of IκB-α were determined by western blotting assay.

RESULTS

Midazolam significantly down-regulated PMA-induced MMP-9 protein expression at concentrations of 5, 10 and 20 µM, the values were 1.95 ±0.09 (p < 0.01), 1.71 ±0.12 (p < 0.01) and 1.35 ±0.20 (p < 0.001), respectively. At concentrations of 5, 10 and 20 µM, it was significantly inhibited the PMA-induced expressions of MMP-1 (2.27 ±0.10, 1.98 ±0.11 and 1.56 ±0.15; p < 0.001) and MMP-13 (0.89 ±0.04, 0.81 ±0.07, and 0.74 ±0.09; p < 0.001), respectively. Midazolam at concentrations of 10 and 20 µM for 15 min significantly reversed the rate of degradation (0.895 ±0.051; p < 0.05 and 0.926 ±0.060; p < 0.01, respectively) of IκB-α in PMA-chondrocyte cells. In addition, this sedative drug inhibited PMA-induced levels of phos-ERK (1.243 ±0.12, 1.108 ±0.16 and 0.903 ±0.19, respectively) and phos-p38 (1.146 ±0.10, 1.063 ±0.13 and 0.946 ±0.18, at concentrations of (5, 10 and 20 µM), respectively.

CONCLUSIONS

These results are important for understanding the mechanism of midazolam in inhibiting PMA-induced MMP expression through the signaling pathways of either NF-κB or ERK/p38 MAPKs down-regulation.

The antagonistic actions of endogenous interleukin-1β and 15-deoxy-Δ12,14-prostaglandin J2 regulate the temporal synthesis of matrix metalloproteinase-9 in sheared chondrocytes

Mechanical overloading of articular cartilage producing hydrostatic stress, tensile strain, and fluid flow results in irreversible cartilage erosion and osteoarthritis (OA). Application of high fluid shear to chondrocytes recapitulates the earmarks of OA as evidenced by the induction of proinflammatory cytokines and prostaglandins, which are capable of inducing the expression of matrix-degrading enzymes. Matrix metalloproteinase-9 (MMP-9) synthesis is detected at early but not late stages of OA. However, the underlying mechanism(s) of the MMP-9 temporal regulation remains unknown. Using the T/C-28a2 chondrocyte cell line as a model system, we demonstrated that high fluid shear induces a marked increase in MMP-9 expression at short shear exposure times (3-6 h), which falls below basal levels after prolonged shear exposure (12-48 h). High fluid shear stress induced the rapid and sustained synthesis of IL-1β, activating PI3K, ERK1/2, and JNK, which are in turn responsible for MMP-9 expression. Prolonged shear exposure (>12 h) induced 15-deoxy-Δ(12,14)-prostaglandin J(2) (15d-PGJ(2)) synthesis, which exerted an antagonistic effect on IL-1β-mediated PI3K-, ERK1/2-, and JNK-dependent NF-κB activation, thereby suppressing MMP-9 expression in human chondrocytes. Reconstructing the signaling network that regulates shear-mediated MMP-9 expression in human chondrocytes may provide insights for developing strategies to treat arthritic disorders.