Restoring the IL-1β/NF-κB-induced impaired chondrogenesis by diallyl disulfide in human adipose-derived mesenchymal stem cells via attenuation of reactive oxygen species and elevation of antioxidant enzymes

Chronic intermittent hypobaric hypoxia alleviates early-stage posttraumatic osteoarthritis via NF-κB/Nrf2 pathway in mice

BACKGROUND

Posttraumatic osteoarthritis (PTOA) is directly associated with early acute articular cartilage injury. Inhibition of cartilage destruction immediately following joint damage can effectively slow or prevent PTOA progression. Therefore, we sought to determine intervention targets and therapeutic strategies in the acute stage of cartilage injury. The benefits of chronic intermittent hypobaric hypoxia (CIHH) extend to various body tissues, but its impact on acute cartilage injury remains unclear. We selected PTOA initiation as the therapeutic window and administered CIHH treatment immediately following cartilage injury initiation to investigate its protective effect on cartilage and molecular mechanism changing with time-varying.

METHODS

The non-invasive PTOA mouse model was established by applying a single rapid specific impact force to the right knee's tibial plateau, initiating load-induced PTOA development, closely resembling the pathological changes in human diseases. Following loading, we inhibited cartilage destruction by treating mice immediately in a hypobaric chamber with a hypobaric hypoxia mimic at 5000 m altitude. Cohorts of mice subjected to distinct experimental conditions were monitored for 3, 7, 14 or 28 days. Safranin O-Fast Green staining, Immunohistochemistry, immunofluorescence, ELISA, and western blotting were performed to evaluate the therapeutic effects of CIHH on cartilage in vivo. The nuclear translocation of NF-κB p65 and Nrf2 were detected by immunofluorescence.

RESULTS

The results showed that inhibiting cartilage destruction using CIHH immediately following acute articular cartilage injury initiation delayed the progression of PTOA, decreased the Mankin score and suppressed the expression of proinflammatory factors, including iNOS, NO, TNF-α, and IL-1β. Meanwhile, immediate CIHH treatment reduced levels of the catabolic enzymes ADAMTS5 and MMP13 in the cartilage matrix, reversed degradation of Collagen II and COMP, and inhibited oxidative stress by decreasing ROS levels. Moreover, CIHH suppressed NF-κB signaling by activating the Nrf2 in vivo studies.

CONCLUSION

Our study demonstrated that immediate CIHH treatment following cartilage injury initiation can attenuate load-induced cartilage damage by activating Nrf2/HO-1 and inhibiting the NF-κB p65 signalling pathways to counteract oxidative stress and inflammatory reactions, enhance the metabolic balance of the cartilage matrix and delay cartilage degeneration. This treatment may represent a potential therapeutic strategy for limiting PTOA progression.

Diallyl disulfide prevents cadmium-induced testicular injury by attenuating oxidative stress, apoptosis, and TLR-4/NF-κB and JAK1/STAT3 signaling and upregulating SIRT1 in rats

BACKGROUND

Cadmium (Cd) is a heavy metal environmental pollutant that can cause serious health problems. Cd can cause structural changes in the testes and exposure to this heavy metal is associated with the loss of sperms and male infertility. The role of oxidative stress and inflammation in Cd toxicity has been acknowledged. Diallyl disulfide (DADS), an organo-sulfur compound found in garlic, possesses antioxidant, anti-inflammatory, and cytoprotective effects. This study evaluated the protective effect of DADS against Cd reproductive toxicity in male rats, emphasizing the involvement of redox imbalance, TLR-4/NF-κB and JAK1/STAT3 signaling, and SIRT1.

METHODS

DADS (10 mg/kg body weight) was administered orally to rats for 14 days and a single dose of Cd (1.2 mg/kg) was injected intraperitoneally on day 7. Blood and samples from the testes were collected for analysis.

RESULTS

Cd caused testicular injury manifested by multiple histopathological changes and loss of sperms from seminiferous tubules. Circulating levels of gonadotropins and testosterone were decreased in Cd-administered rats. DADS prevented Cd-induced testicular injury and ameliorated serum levels of gonadotropins and testosterone. Cd increased testicular reactive oxygen species (ROS) and malondialdehyde (MDA) and upregulated TLR-4, NF-κB, pro-inflammatory cytokines, JAK1 and STAT3 phosphorylation, Bax and caspase-3, while decreased antioxidants and Bcl-2. DADS effectively decreased ROS and MDA, downregulated TLR-4, NF-κB, JAK1, STAT3, pro-inflammatory cytokines and pro-apoptosis markers in Cd-administered rats. In addition, DADS enhanced antioxidants, Bcl-2, SIRT1 and cytoglobin in the testis of Cd-administered rats.

CONCLUSION

DADS prevents Cd-induced testicular injury by attenuating oxidative stress, apoptosis, and TLR-4/NF-κB and JAK1/STAT3 signaling, and upregulating SIRT1 and antioxidants.

Polydeoxyribonucleotide ameliorates IL-1β-induced impairment of chondrogenic differentiation in human bone marrow-derived mesenchymal stem cells

Osteoarthritis (OA) is a degenerative disease of the joints, prevalent worldwide. Polydeoxyribonucleotide (PDRN) is used for treating knee OA. However, the role of PDRN in IL-1β-induced inflammatory responses in human bone marrow-derived mesenchymal stem cells (hBMSCs) remains unknown. Here, we investigated the role of PDRN in IL-1β-induced impairment of chondrogenic differentiation in hBMSCs. hBMSCs treated with PDRN showed a large micromass, enhanced safranin O and alcian blue staining intensity, and increased expression of chondrogenic genes in IL-1β-induced inflammatory responses, in addition to regulation of catabolic and anabolic genes. In addition, PDRN treatment suppressed the expression of inflammatory cytokines and mitigated IL-1β-induced apoptosis in hBMSCs. Mechanistically, PDRN treatment increased the formation of cyclic adenosine monophosphate (cAMP) and upregulated the phosphorylation of cAMP-dependent protein kinase A (PKA)/cAMP response element binding protein (CREB) through the adenosine A2A receptor in hBMSCs and thus blocked the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathway. Thus, IL-1β-induced expression of inflammatory cytokines in hBMSCs was directly reduced by adenosine A2A receptor activation. Based on our results, we suggest that PDRN may be a promising MSC-based therapeutic agent for OA.

Enhancing high-density microalgae cultivation via exogenous supplementation of biostimulant derived from onion peel waste for sustainable biodiesel production

Microalgae demonstrate significant potential as a source of liquid-based biofuels. However, increasing biomass productivity in existing cultivation systems is a critical prerequisite for their successful integration into large-scale operations. Thus, the current work aimed to accelerate the growth of C. vulgaris via exogenous supplementation of biostimulant derived from onion peel waste. Under the optimal growth conditions, which entailed a biostimulant dosage of 37.5% v/v, a pH of 3, an air flow rate of 0.4 L/min, and a 2% v/v inoculum harvested during the mid-log phase, yielded a maximum biomass concentration of 1.865 g/L. Under the arbitrarily optimized parameters, a comparable growth pattern was evident in the upscaled cultivation of C. vulgaris, underscoring the potential commercial viability of the biostimulant. The biostimulant, characterized through gas chromatography-mass spectrometry (GC-MS) analysis, revealed a composition rich in polyphenolic and organo-sulphur compounds, notably including allyl trisulfide (28.13%), methyl allyl trisulfide (23.04%), and allyl disulfide (20.78%), showcasing potent antioxidant properties. Additionally, microalgae treated with the biostimulant consistently retained their lipid content at 18.44% without any significant reduction. Furthermore, a significant rise in saturated fatty acid (SFA) content was observed, with C16:0 and C18:1 dominating both bench-scale (44.08% and 14.01%) and upscaled (51.12% and 13.07%) microalgae cultures, in contrast to the control group where C18:2 was prevalent. Consequently, SFA contents reached 54.35% and 65.43% in bench-scale and upscaled samples respectively, compared to 33.73% in the control culture. These compositional characteristics align well with the requirements for producing high-quality crude biodiesel.

Therapeutic potential of hydrogen sulfide in osteoarthritis development

The pathological mechanisms and treatments of osteoarthritis (OA) are critical topics in medical research. This paper reviews the regulatory mechanisms of hydrogen sulfide (H2S) in OA and the therapeutic potential of H2S donors. The review highlights the importance of changes in the endogenous H2S pathway in OA development and systematically elaborates on the role of H2S as a third gaseous transmitter that regulates inflammation, oxidative stress, and pain associated with OA. It also explains how H2S can lessen bone and joint inflammation by inhibiting leukocyte adhesion and migration, reducing pro-inflammatory mediators, and impeding the activation of key inflammatory pathways such as nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK). Additionally, H2S is shown to mitigate mitochondrial dysfunction and endoplasmic reticulum stress, and to modulate Nrf2, NF-κB, PI3K/Akt, and MAPK pathways, thereby decreasing oxidative stress-induced chondrocyte apoptosis. Moreover, H2S alleviates bone and joint pain through the activation of Kv7, K-ATP, and Nrf2/HO-1-NQO1 pathways. Recent developments have produced a variety of H2S donors, including sustained-release H2S donors, natural H2S donors, and synthetic H2S donors. Understanding the role of H2S in OA can lead to the discovery of new therapeutic targets, while innovative H2S donors offer promising new treatments for patients with OA.

Melatonin Attenuates the Progression of Osteoarthritis in Rats by Inhibiting Inflammation and Related Oxidative Stress on the Surface of Knee Cartilage

Objective

To investigate the correlation between melatonin and osteoarthritis (OA) in rats. To explore the relevant mechanisms in the occurrence and development of osteoarthritis in rats, and to further understand the disease of osteoarthritis.

Methods

Forty healthy 6‐month‐old male SD rats were randomly divided into two groups: sham and drug intervention groups. Pre‐OA modeling, enzyme‐linked immunosorbent assay was employed to detect the levels of IL‐1β, IL‐6, COX‐2, and melatonin in the serum of the rats in each group. For OA modeling, we administered an injection of papain into the knee cavity of all rats. The levels of IL‐1β, IL‐6, and COX‐2 in the serum of rats in each group were detected 2 weeks after the modeling. Additionally, 2 weeks after the modeling, the rats in the drug intervention group were intraperitoneally injected with melatonin antagonists. The rats in the sham group were intraperitoneally injected with normal saline for 2 weeks. The levels of IL‐1β, IL‐6, and COX‐2 in the serum of each group were measured at the second, third, and fourth weeks after the drug intervention, and the levels of melatonin in the serum were measured at the second week after the drug intervention. Finally, the rats were euthanized by cervical dislocation, and pathological sections were collected from the knee joint to observe the pathological tissue changes under a microscope, and Mankin score was determined. The independent samples t‐test method was used for analysis.

Results

The imaging examination after the drug intervention showed that the modeling of knee osteoarthritis in rats was successful. In the pathological findings, HE staining showed a legible cartilage structure of each layer, with cartilage proliferation and partial cartilage tearing to the radial layer. The tide line was intact; toluidine blue staining revealed more obvious changes. The differences among the mean values of IL‐6, IL‐1β, and COX‐2 measured in each period were statistically significant (t = 5.50, p < 0.05). The measured mean values of IL‐6, IL‐1β, and COX‐2 revealed statistically significant differences among the groups (t = 2.01, p < 0.05). The intergroup comparison of the Mankin scores in each period showed statistically significant differences.

Conclusion

Melatonin may inhibit inflammation and associated oxidative stress on the surface of knee cartilage. It may be related to the repair and regeneration of articular surface cartilage during the development of OA in the rat knee joint.

Biological Functions of Diallyl Disulfide, a Garlic-Derived Natural Organic Sulfur Compound

Garlic is widely accepted as a functional food and an excellent source of pharmacologically active ingredients. Diallyl disulfide (DADS), a major bioactive component of garlic, has several beneficial biological functions, including anti-inflammatory, antioxidant, antimicrobial, cardiovascular protective, neuroprotective, and anticancer activities. This review systematically evaluated the biological functions of DADS and discussed the underlying molecular mechanisms of these functions. We hope that this review provides guidance and insight into the current literature and enables future research and the development of DADS for intervention and treatment of multiple diseases.

Involvement of Rho-kinase/IκB-α/NF-κB activation in IL-1β-induced inflammatory response and oxidative stress in human chondrocytes

It has been clearly indicated that osteoarthritis (OA) is an inflammatory and degenerative disease that could be promoted by Rho-kinase (ROCK); however, little is known about the role of ROCK/inhibitor κB alpha (IκB-α)/nuclear factor-κB (NF-κB) p65 pathway activation in interleukin-1β (IL-1β) induced inflammatory response and oxidative stress in primary human chondrocytes. To test this hypothesis, we focused on determining ROCK-II, IκB-α, p-IκB-α, NF-κB p65, p-NF-κB p65, IL-6, tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), p22phox, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subtype 4 (NOX4) protein expression, ROCK-II activity, NADPH oxidase levels, and total antioxidant capacity (TAC) in the presence and absence of ROCK-inhibitor fasudil. IL-1β (2 ng·mL-1, 24 h) increased the expression of ROCK-II, p-IκB-α, NF-κB p65, p-NF-κB p65, IL-6, TNF-α, COX-2, and p22phox proteins, and decreased the expression of IκB-α, and the NOX4 protein level did not alter. ROCK activity and NADPH oxidase levels were increased, whereas the TAC was decreased by IL-1β. Fasudil (10-5-10-7 M) reversed all these changes induced by IL-1β. These results demonstrate that ROCK/IκB-α/NF-κB p65 pathway activation contributes to the IL-1β-induced inflammatory response and oxidative stress, and thus, ROCK inhibition might be a beneficial treatment option for OA patients mainly based on its anti-inflammatory and antioxidant effects.

A comprehensive understanding about the pharmacological effect of diallyl disulfide other than its anti-carcinogenic activities

Diallyl disulfide (DADS), an oil-soluble sulfur compound that is responsible for the biological effects of garlic, displays numerous biological activities, among which its anti-cancer activities are the most famous ones. In recent years, the pharmacological effects of DADS other than its anti-carcinogenic activities have attracted numerous attentions. For example, it has been reported that DADS can prevent the microglia-mediated neuroinflammatory response and depression-like behaviors in mice. In the cardiovascular system, DADS administration was found to ameliorate the isoproterenol- or streptozotocin-induced cardiac dysfunction via the activation of the nuclear factor E2-related factor 2 (Nrf2) and insulin-like growth factor (IGF)-phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) signaling. DADS administration can also produce neuroprotective effects in animal models of Alzheimer's disease and protect the heart, endothelium, liver, lung, and kidney against cellular or tissue damages induced by various toxic factors, such as the oxidized-low density lipoprotein (ox-LDL), carbon tetrachloride (CCl₄), ethanol, acetaminophen, Cis-Diammine Dichloroplatinum (CisPt), and gentamicin. The major mechanisms of action of DADS in disease prevention and/or treatment include inhibition of inflammation, oxidative stress, and cellular apoptosis. Mechanisms, including the activation of Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), protein kinase A (PKA), and cyclic adenosine monophosphate-response element binding protein (CREB) and the inhibition of histone deacetylases (HDACs), can also mediate the cellular protective effects of DADS in different tissues and organs. In this review, we summarize and discuss the pharmacological effects of DADS other than its anti-carcinogenic activities, aiming to reveal more possibilities for DADS in disease prevention and/or treatment.

Rapamycin-Induced Autophagy Promotes the Chondrogenic Differentiation of Synovium-Derived Mesenchymal Stem Cells in the Temporomandibular Joint in Response to IL-1β

Cartilage defects in temporomandibular disorders (TMD) lead to chronic pain and seldom heal. Synovium-derived mesenchymal stem cells (SMSCs) exhibit superior chondrogenesis and have become promising seed cells for cartilage tissue engineering. However, local inflammatory conditions that affect the repair of articular cartilage by SMSCs present a challenge, and the specific mechanism through which the function remains unclear. Thus, it is important to explore the chondrogenesis of SMSCs under inflammatory conditions of TMD such that they can be used more effectively in clinical treatment. In this study, we obtained SMSCs from TMD patients with severe cartilage injuries. In response to stimulation with IL-1β, which is well known as one of the most prevalent cytokines in TMD, MMP13 expression increased, while that of SOX9, aggrecan, and collagen II decreased during chondrogenic differentiation. At the same time, IL-1β upregulated the expression of mTOR and decreased the ratio of LC3-II/LC3-I and the formation of autophagosomes. Further study revealed that rapamycin pretreatment promoted the migration of SMSCs and the expression of chondrogenesis-related markers in the presence of IL-1β by inducing autophagy. 3-Benzyl-5-((2-nitrophenoxy)methyl)-dihydrofuran-2(3H)-one (3BDO), a new activator of mTOR, inhibited autophagy and increased the expression of p-GSK3βser9 and β-catenin, simulating the effect of IL-1β stimulation. Furthermore, rapamycin reduced the expression of mTOR, whereas the promotion of LC3-II/LC3-I was blocked by the GSK3β inhibitor TWS119. Taken together, these results indicate that rapamycin enhances the chondrogenesis of SMSCs by inducing autophagy, and GSK3β may be an important regulator in the process of rapamycin-induced autophagy. Thus, inducing autophagy may be a useful approach in the chondrogenic differentiation of SMSCs in the inflammatory microenvironment and may represent a novel TMD treatment.

Permanent cystathionine-β-Synthase gene knockdown promotes inflammation and oxidative stress in immortalized human adipose-derived mesenchymal stem cells, enhancing their adipogenic capacity

In the present study, we aimed to investigate the impact of permanent cystathionine-β-Synthase (CBS) gene knockdown in human telomerase reverse transcriptase (hTERT) immortalized human adipose-derived mesenchymal stem cells (ASC52telo) and in their capacity to differentiate into adipocytes. CBS gene KD in ASC52telo cells led to increased cellular inflammation (IL6, CXCL8, TNF) and oxidative stress markers (increased intracellular reactive oxygen species and decreased reduced glutathione levels) in parallel to decreased H₂S production and rejuvenation (LC3 and SIRT1)-related gene expression. In addition, CBS gene KD in ASC52telo cells resulted in altered mitochondrial respiratory function, characterised by decreased basal respiration (specifically proton leak) and spare respiratory capacity, without significant effects on cell viability and proliferation. In this context, shCBS-ASC52telo cells displayed enhanced adipogenic (FABP4, ADIPOQ, SLC2A4, CEBPA, PPARG)-, lipogenic (FASN, DGAT1)- and adipocyte (LEP, LBP)-related gene expression markers, decreased expression of proinflammatory cytokines, and increased intracellular lipid accumulation during adipocyte differentiation compared to control ASC52telo cells. Otherwise, the increased adipogenic potential of shCBS-ASC52telo cells was detrimental to the ability to differentiate into osteogenic linage. In conclusion, this study demonstrated that permanent CBS gene KD in ASC52telo cells promotes a cellular senescence phenotype with a very increased adipogenic potential, promoting a non-physiological enhanced adipocyte differentiation with excessive lipid storage.

Effective treatment of drug-resistant lung cancer via a nanogel capable of reactivating cisplatin and enhancing early apoptosis

Cisplatin resistance is a daunting obstacle in cancer therapy and one of the major causes for treatment failure due to the inadequate drug activity and apoptosis induction. To overcome cisplatin resistance, we proposed a multifunctional nanogel (designated as Valproate-D-Nanogel) capable of reactivating cisplatin and enhancing early apoptosis. This Valproate-D-Nanogel was prepared through copolymerizing carboxymethyl chitosan with diallyl disulfide and subsequent grafting with valproate to reverse the drug-resistance in cisplatin-resistant human lung adenocarcinoma cancer. It can significantly increase the proportion of G2/M phase (up to 3.2-fold enhancement) to reactivate cisplatin via high level of G2/M arrest induced by valproate. Meanwhile, the intracellular ROS-P53 crosstalk can be upregulated by diallyl disulfide (up to 8-fold increase of ROS) and valproate (up to 18-fold increase of P53) to enhance early apoptosis. The synchronization of enhanced G2/M arrest and ROS-P53 crosstalk devotes to reverse the cisplatin resistance with a high level of resistance reversion index (50.22). As a result, improved in vivo tumor inhibition (up to 15-fold higher compared to free cisplatin) and decreased systemic toxicity was observed after treatment with Valproate-D-Nanogels. Overall, this nanogel can effectively inhibit cisplatin-resistance cancer through combined pathways and provides an effective approach for overcoming cisplatin-resistance in cancer treatment.

Improving Cell Therapy Survival and Anabolism in Harsh Musculoskeletal Disease Environments

Cell therapies are an up and coming technology in orthopedic medicine that has the potential to provide regenerative treatments for musculoskeletal disease. Despite numerous cell therapies showing preclinical success for common musculoskeletal indications of disc degeneration and osteoarthritis, there have been mixed results when testing these therapies in humans during clinical trials. A theory behind the mixed success of these cell therapies is that the harsh microenvironments of the disc and knee they are entering inhibit their anabolism and survival. Therefore, there is much ongoing research looking into how to improve the survival and anabolism of cell therapies within these musculoskeletal disease environments. This includes research into improving cell function under specific microenvironmental conditions known to exist in the intervertebral disc (IVD) and knee environment such as hypoxia, low-nutrient conditions, hyperosmolarity, acidity, and inflammation. This research also includes improving differentiation of cells into desired native cell phenotypes to better enhance their survival and anabolism in the knee and IVD. This review highlights the effects of specific musculoskeletal microenvironmental challenges on cell therapies and what research is being done to overcome these challenges. Impact statement While there has been significant clinical interest in using cell therapies for musculoskeletal pathologies in the knee and intervertebral disc, cell therapy clinical trials have had mixed outcomes. The information presented in this review includes the environmental challenges (i.e., acidic pH, inflammation, hyperosmolarity, hypoxia, and low nutrition) that cell therapies experience in these pathological musculoskeletal environments. This review summarizes studies that describe various approaches to improving the therapeutic capability of cell therapies in these harsh environments. The result is an overview of what approaches can be targeted and/or combined to develop a more consistent cell therapy for musculoskeletal pathologies.

The Interaction between Joint Inflammation and Cartilage Repair

Background

Articular cartilage lesions occur frequently but unfortunately damaged cartilage has a very limited intrinsic repair capacity. Therefore, there is a high need to develop technology that makes cartilage repair possible. Since joint damage will lead to (sterile) inflammation, development of this technology has to take into account the effects of inflammation on cartilage repair.

Methods

A literature search has been performed including combinations of the following keywords; cartilage repair, fracture repair, chondrogenesis, (sterile) inflammation, inflammatory factors, macrophage, innate immunity, and a number of individual cytokines. Papers were selected that described how inflammation or inflammatory factors affect chondrogenesis and tissue repair. A narrative review is written based on these papers focusing on the role of inflammation in cartilage repair and what we can learn from findings in other organs, especially fracture repair.

Results

The relationship between inflammation and tissue repair is not straightforward. Acute, local inflammation stimulates fracture repair but appears to be deleterious for chondrogenesis and cartilage repair. Systemic inflammation has a negative effect on all sorts of tissue repair.

Conclusion

Findings on the role of inflammation in fracture repair and cartilage repair are not in line. The currently widely used models of chondrogenesis, using high differentiation factor concentrations and corticosteroid levels, are not optimal. To make it possible to draw more valid conclusions about the role of inflammation and inflammatory factors on cartilage repair, model systems must be developed that better mimic the real conditions in a joint with damaged cartilage.

Diallyl disulfide alleviates inflammatory osteolysis by suppressing osteoclastogenesis via NF-κB-NFATc1 signal pathway

Skeletal homeostasis is closely effectuated by the regulation of bone formation and bone resorption. Osteoclasts are multinuclear giant cells responsible for bone resorption. Overactivated osteoclasts and excessive bone resorption result in various lytic bone diseases, such as osteoporosis, osteoarthritis, periprosthetic infection, and inflammatory aseptic loosening of orthopedic implants. In consideration of the severe side effects caused by the currently available drugs, exploitation of novel drugs has gradually attracted attention. Because of its anti-inflammatory, antioxidant, and antitumor capacities, diallyl disulfide (DADS), a major oil-soluble organosulfur ingredient compound derived from garlic, has been widely researched. However, the effects of DADS on osteoclasts and lytic bone diseases are still unknown. In this study, we investigated the effects of DADS on receptor activator of NF-κB ligand (RANKL)- and LPS-mediated osteoclastogenesis, LPS-stimulated proinflammatory cytokines related to osteoclasts, and LPS-induced inflammatory osteolysis. The results showed that DADS significantly inhibited RANKL-mediated osteoclast formation, fusion, and bone resorption in a dose-dependent manner via inhibiting the NF-κB and signal transducer and activator of transcription 3 signaling and restraining the interaction of NF-κB p65 with nuclear factor of activated T cells cytoplasmic 1. Furthermore, DADS also markedly suppressed LPS-induced osteoclastogenesis and reduced the production of proinflammatory cytokines with LPS stimulation to indirectly mediate osteoclast formation. Consistent with the in vitro results, DADS prevented the LPS-induced severe bone loss by blocking the osteoclastogenesis. All of the results indicate that DADS may be a potential and exploitable drug used for preventing and impeding osteolytic lesions.-Yang, J., Tang, R., Yi, J., Chen, Y., Li, X., Yu, T., Fei, J. Diallyl disulfide alleviates inflammatory osteolysis by suppressing osteoclastogenesis via NF-κB-NFATc1 signal pathway.

Protective effects of quercetin against inflammation and oxidative stress in a rabbit model of knee osteoarthritis

Hit, Lead & Candidate Discovery This study investigated the effects of a natural phenolic compound quercetin on surgical-induced osteoarthritis (OA) in rabbits. Forty-eight New Zealand White rabbits were used to establish OA model by Hulth modified method, and subsequently randomized into untreated OA group (treatment was drinking water), celecoxib treated group (celecoxib 100 mg kg^-1 by gavage), and quercetin treated group (25 mg kg^-1 by gavage). Sixteen nonoperated rabbits served as the normal controls (drinking water was given). The treatment (length: 4 weeks) started on the 5th week postoperation when the OA pathological changes were manifested. Expressions of superoxide dismutase (SOD), matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in serum, synovial fluid, and synovial tissue were measured at 8 and 12 weeks postoperation. Pathological analysis was performed with synovial tissue section and Osteoarthritis Research Society International histopathology grading and staging scores were determined. The quercetin treated group showed higher SOD and TIMP-1 expressions but lower MMP-13 expression than untreated OA group in the serum, synovial fluid and synovial tissues (p < .05). There was no significant difference in the SOD, MMP-13 and TIMP-1 expressions between the quercetin-treated and celecoxib-treated groups. The MMP-13/TIMP-1 ratio of the quercetin treated group was significantly lower than that of the untreated OA group (p < .05). Quercetin can up-regulate SOD and TIMP-1, down-regulate MMP-13, and improve the degeneration of OA through weakening the oxidative stress responses and inhibiting the degradation of cartilage extracellular matrix.

Diallyl disulfide down-regulates calreticulin and promotes C/EBPα expression in differentiation of human leukaemia cells

Diallyl disulfide (DADS), the main active component of the cancer fighting allyl sulfides found in garlic, has shown potential as a therapeutic agent in various cancers. Previous studies showed DADS induction of HL-60 cell differentiation involves down-regulation of calreticulin (CRT). Here, we investigated the mechanism of DADS-induced differentiation of human leukaemia cells and the potential involvement of CRT and CCAAT enhancer binding protein-α (C/EBPα). We explored the expression of CRT and C/EBPα in clinical samples (20 healthy people and 19 acute myeloid leukaemia patients) and found that CRT and C/EBPα expressions were inversely correlated. DADS induction of differentiation of HL-60 cells resulted in down-regulated CRT expression and elevated C/EBPα expression. In severe combined immunodeficiency mice injected with HL-60 cells, DADS inhibited the growth of tumour tissue and decreased CRT levels and increased C/EBPα in vivo. We also found that DADS-mediated down-regulation of CRT and up-regulation of C/EBPα involved enhancement of reactive oxidative species. RNA immunoprecipitation revealed that CRT bound C/EBPα mRNA, indicating its regulation of C/EBPα mRNA degradation by binding the UG-rich element in the 3' untranslated region of C/EBPα. In conclusion, the present study demonstrates the C/EBPα expression was correlated with CRT expression in vitro and in vivo and the molecular mechanism of DADS-induced leukaemic cell differentiation.