Oxymatrine protects articular chondrocytes from IL-1ß-induced damage through autophagy activation via AKT/mTOR signaling pathway inhibition.

BACKGROUND: Osteoarthritis (OA) is a common degenerative joint disease characterized by persistent articular cartilage degeneration and synovitis. Oxymatrine (OMT) is a quinzolazine alkaloid extracted from the traditional Chinese medicine, matrine, and possesses anti-inflammatory properties that may help regulate the pathogenesis of OA; however, its mechanism has not been elucidated. This study aimed to investigate the effects of OMT on interleukin-1ß (IL-1ß)-induced damage and the potential mechanisms of action. METHODS: Chondrocytes were isolated from Sprague-Dawley rats. Toluidine blue and Collagen II immunofluorescence staining were used to determine the purity of the chondrocytes. Thereafter, the chondrocytes were subjected to IL-1ß stimulation, both in the presence and absence of OMT, or the autophagy inhibitor 3-methyladenine (3-MA). Cell viability was assessed using the MTT assay and SYTOX Green staining. Additionally, flow cytometry was used to determine cell apoptosis rate and reactive oxygen species (ROS) levels. The protein levels of AKT, mTOR, LC3, P62, matrix metalloproteinase-13, and collagen II were quantitatively analyzed using western blotting. Immunofluorescence was used to assess LC3 expression. RESULTS: OMT alleviated IL-1ß-induced damage in chondrocytes, by increasing the survival rate, reducing the apoptosis rates of chondrocytes, and preventing the degradation of the cartilage matrix. In addition, OMT decreased the ROS levels and inhibited the AKT/mTOR signaling pathway while promoting autophagy in IL-1ß treated chondrocytes. However, the effectiveness of OMT in improving chondrocyte viability under IL-1ß treatment was limited when autophagy was inhibited by 3-MA. CONCLUSIONS: OMT decreases oxidative stress and inhibits the AKT/mTOR signaling pathway to enhance autophagy, thus inhibiting IL-1ß-induced damage. Therefore, OMT may be a novel and effective therapeutic agent for the clinical treatment of OA.

Trelagliptin ameliorates IL-1ß-impaired chondrocyte function via the AMPK/SOX-9 pathway.

Chondrocyte dysregulation plays a critical role in the development of osteoarthritis (OA). The pro-inflammatory cytokine interleukin-1ß (IL-1ß) activates chondrocytes and degrades the structural extracellular matrix (ECM). These events are the important mechanism of OA. Trelagliptin, a selective inhibitor of dipeptidyl Peptidase 4 (DPP-4) used for the treatment of type 2 diabetes mellitus (T2DM), has displayed a wide range of anti-inflammatory capacities. The effects of Trelagliptin in OA and chondrocytes have not been tested before. Here, we show that Trelagliptin mitigates IL-1ß-induced production of inflammatory cytokines such as interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor-alpha (TNF-α) in human chondrocytes. Trelagliptin ameliorates IL-1ß-induced oxidative stress by reducing the generation of reactive oxygen species (ROS). Particularly, the presence of Trelagliptin prevents IL-1ß-induced reduction of Acan genes and the protein Aggrecan. Moreover, we show that Trelagliptin restores IL-1ß-induced reduction of SOX-9 and that the knockdown of SOX-9 abolishes the protective effects of Trelagliptin. Mechanistically, we demonstrate that AMPK is required for the amelioration of Trelagliptin on SOX-9- reduction by IL-1ß. Collectively, our study demonstrates that the DPP-4 inhibitor Trelagliptin has a protective effect on chondrocyte function. Trelagliptin may have the potential role to antagonize chondrocyte-derived inflammation in OA.

FABP4 knockdown suppresses inflammation, apoptosis and extracellular matrix degradation in IL-1ß-induced chondrocytes by activating PPARγ to regulate the NF-κB signaling pathway.

Osteoarthritis (OA) is a common degenerative disease that can lead to severe joint pain and loss of function, seriously threatening the health and normal life of patients. At present, the pathogenesis of OA remains to be clarified. Recent studies have shown that fatty acid­binding protein 4 (FABP4) is increased in the plasma and synovial fluid of patients with OA. However, the effect of FABP4 on OA is unclear. The present study established IL­1ß­induced ATDC5 cells with FABP4 knockdown. Next, cell viability was detected with Cell Counting Kit­8 assay. The content of inflammatory factors, prostaglandin E2 and glycosaminoglycan (GAG) was detected via ELISA. The levels of reactive oxygen species (ROS) and superoxide dismutase (SOD) in cells were detected by using ROS and SOD kits, respectively. TUNEL staining was used to detect the apoptosis level. Western blotting was used to detect the expression levels of proteins. The results revealed that FABP4 was upregulated in IL­1ß­induced ATDC5 cells. Knockdown of FABP4 increased cell viability, reduced inflammatory damage, oxidative stress and apoptosis in IL­1ß­induced ATDC5 cells. Following FABP4 knockdown, the expression of matrix metalloproteinases (MMP3, MMP9 and MMP13) of IL­1ß­induced ATDC5 cells was reduced, and the expression of GAG was promoted. FABP4 knockdown also inhibited the expression of NF­κB p65 and enhanced peroxisome proliferator­activated receptor (PPAR)γ expression. However, the presence of PPARγ inhibitor blocked the aforementioned effects of FABP4 on IL­1ß­induced ATDC5 cells. In conclusion, FABP4 knockdown suppressed the inflammation, oxidative stress, apoptosis and extracellular matrix degradation of IL­1ß­induced chondrocytes by activating PPARγ to inhibit the NF­κB signaling pathway.

Gossypol ameliorates the IL-1ß-induced apoptosis and inflammation in chondrocytes by suppressing the activation of TLR4/MyD88/NF-κB pathway via downregulating CX43.

The effects of anti-inflammatory drug gossypol on osteoarthritis (OA) treatment were discussed in this paper. After identified using toluidine blue and immunofluorescence staining of type II collagen, chondrocytes from OA patients were treated with interleukin-1ß (IL-1ß), gossypol, and overexpressed connexin43 (CX43). In treated chondrocytes, according to MTT assay and flow cytometry, gossypol increased viability and reduced apoptosis of IL-1ß induced chondrocytes. Enzyme linked immunosorbent assay (ELISA) suggested that gossypol downregulated inflammatory tumor necrosis factor (TNF)-α level. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot confirmed that gossypol downregulated CX43, nuclear factor-kappa B (NF-κB) p65, TNF-α, toll like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (MyD88) and interleukin-6 (IL-6) expressions. Besides, overexpressed CX43 reversed the effects of gossypol on viability, apoptosis, and expressions of factors related to TLR4/MyD88/NF-κB pathway of IL-1ß-induced chondrocytes. In conclusion, gossypol ameliorates IL-1ß-induced apoptosis and inflammation in chondrocytes by suppressing TLR4/MyD88/NF-κB pathway via downregulating CX43.

Platelet-rich plasma attenuates interleukin-1ß-induced apoptosis and inflammation in chondrocytes through targeting hypoxia-inducible factor-2α.

Osteoarthritis (OA) is a prevailing chronic disease in Orthopedics that characterized with severely damaged cartilage and subchondral bone, thus leading to profound disorders of synovial joints. Platelet-rich plasma (PRP) has been applied as a popular non-operative treatment option for promoting musculoskeletal healing. Our previous work demonstrated that PRP protected chondrocytes from interleukin-1ß (IL-1ß)-induced apoptosis in vitro. However, the underlying mechanism behind the treatment remains unclear. The current study aimed to unveil the molecular signaling underlying its protective role in chondrocytes. Rat chondrocytes were isolated from newborn Sprague Dawley rats and treated with 5 ng/mL IL-1ß for 24 h. The expression of hypoxia-inducible factor 2α (HIF-2α) was determined in both mRNA and protein levels. Next, loss- and gain-of-function assays for HIF-2α were performed using small-interfering RNA (siRNA) specific for HIF-2α and adenovirus-mediated HIF-2α overexpression, respectively. In addition, cell apoptosis markers, matrix metalloproteinase (MMP)-1, 3, -9 and -13, and extracellular matrix-related genes were evaluated. Our results demonstrated that IL-1ß induced distinct inflammation in chondrocytes. In addition, HIF-2α upregulated in the IL-1ß-treated chondrocytes compared to the untreated cells. Interestingly, 10% PRP protected chondrocytes against IL-1ß-induced apoptosis and matrix degradation, and meanwhile suppressed the HIF-2α activation. Furthermore, HIF-2α siRNA and HIF-2α overexpression experiments indicated that PRP induced chondroprotection through targeting HIF-2α. Taken together, our findings indicated that PRP attenuates IL-1ß-induced chondrocyte apoptosis and inflammation at least partially through inhibiting HIF-2α.

18ß-Glycyrrhetinic acid inhibits IL-1ß-induced inflammatory response in mouse chondrocytes and prevents osteoarthritic progression by activating Nrf2.

Osteoarthritis (OA) is presently the most prevalent form of chronic degenerative joint disease, which is characterized by erosion of articular cartilage, subchondral bone sclerosis and synovitis. Accumulating evidence has revealed that 18ß-glycyrrhetinic acid (18ß-GA), a major bioactive component derived from Glycyrrhiza glabra, exerts anti-inflammatory effects on several diseases. However, the anti-inflammatory effects of 18ß-GA on OA remain undetermined. The present study aimed to investigate the anti-inflammatory effects of 18ß-GA on chondrocytes and the therapeutic effects on destabilization of the medial meniscus destabilization (DMM) mouse models of OA. For the in vivo study, we randomly divided the mice into three groups: vehicle control (n = 15), sham (n = 15) and 18ß-GA (n = 15) groups, and treated them with similar doses (50 mg kg-1 day-1) of 18ß-GA or saline. Cartilage tissues were harvested from the mice for histological analyses eight weeks after operation. For the in vitro studies, mouse chondrocytes were administered with 10 ng mL-1 interleukin-1ß (IL-1ß) after being treated with 18ß-GA at various concentrations. In vitro assays revealed that treatment with 18ß-GA considerably suppressed the expression of pro-inflammatory mediators and cytokines, including prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), nitric oxide (NO), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and interleukin-6 (IL-6), which were induced by IL-1ß. Furthermore, 18ß-GA decreased the expression of matrix-degrading proteases, including matrix metalloproteinase 13 (MMP13) and A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5), in a concentration-dependent manner, which mediated extracellular matrix (ECM) degradation. 18ß-GA reversed aggrecan and type II collagen degradation. Furthermore, we observed that 18ß-GA significantly suppressed IL-1ß-induced nuclear factor kappa B (NF-κB) activation by activating the nuclear factor erythroid-derived 2-like 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway in vitro and in vivo. Experiments demonstrated that 18ß-GA might alleviate the progression of OA in the DMM mouse model in vivo. The findings demonstrate that 18ß-GA reduces inflammation induced by IL-1ß in chondrocytes. Therefore, 18ß-GA could be a potential therapeutic agent for OA.

Anagliptin prevented interleukin 1ß (IL-1ß)-induced cellular senescence in vascular smooth muscle cells through increasing the expression of sirtuin1 (SIRT1).

Vascular smooth muscle cell senescence plays a pivotal role in the pathogenesis of atherosclerosis. Anagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor for the treatment of hyperglycemia. Recent progress indicates that DPP-4 inhibitors show a wide range of cardiovascular benefits. We hypothesize that Anagliptin plays a role in vascular smooth muscle cell senescence and this may imply its modulation of atherosclerosis. Here, the beneficial effect of Anagliptin against interleukin 1ß (IL-1ß)-induced cell senescence in vascular smooth muscle cells was studied to learn the promising therapeutic capacity of Anagliptin on atherosclerosis. Firstly, we found that Anagliptin treatment ameliorated the elevated secretions of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), and macrophage chemoattractant protein-1 (MCP-1). Secondly, our findings indicate that exposure to IL-1ß reduced telomerase activity from 26.7 IU/L to 15.8 IU/L, which was increased to 20.3 and 24.6 IU/L by 2.5 and 5 µM Anagliptin, respectively. In contrast, IL-1ß stimulation increased senescence- associated ß-galactosidase (SA-ß-gal) staining to 3.1- fold compared to the control group, it was then reduced to 2.3- and 1.6- fold by Anagliptin dose-dependently. Thirdly, Anagliptin dramatically reversed the upregulated p16, p21, and downregulated sirtuin1 (SIRT1) in IL-1ß-treated vascular smooth muscle cells. Lastly, the protective effect of Anagliptin against cellular senescence in vascular smooth muscle cells was abolished by silencing of SIRT1. In conclusion, Anagliptin protects vascular smooth muscle cells from cytokine-induced senescence, and the action of Anagliptin in vascular smooth muscle cells requires SIRT1 expression.

Higenamine mitigates interleukin-1ß-induced human nucleus pulposus cell apoptosis by ROS-mediated PI3K/Akt signaling.

Intervertebral disc degeneration (IDD) is a natural problem linked to the inflammation. Higenamine exerts multiple pharmacological properties in inflammation-related disorders. Our study aimed to explore the function of higenamine on interleukin (IL)-1ß-caused apoptosis of human nucleus pulposus cells (HNPCs). Cell apoptosis was investigated by TUNEL and flow cytometry. Apoptosis-related biomarkers were determined by qRT-PCR or Western blotting. The protein in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling was measured by Western blotting. We found that higenamine showed little effect on cell apoptosis, but mitigated IL-1ß-caused apoptosis in a dose-dependent pattern. Higenamine attenuated IL-1ß-induced decrease of Bcl-2 and increase of Bax and cleaved caspase-3. Higenamine did not affect the reactive oxygen species (ROS) level and the PI3K/Akt signaling, but attenuated IL-1ß-induced ROS production and inhibition of the PI3K/Akt signaling. IL-1ß repressed the activation of the PI3K/Akt pathway, but ROS inhibition using N-acetylcysteine (NAC) rescued this pathway. The PI3K/Akt signaling suppression using LY294002 reversed the inhibitive effect of higenamine on IL-1ß-caused apoptosis, and this effect was weakened by ROS inhibition. In conclusion, higenamine attenuates IL-1ß-caused apoptosis of HNPCs via ROS-mediated PI3K/Akt pathway.

Small molecule natural compound targets the NF-κB signaling and ameliorates the development of osteoarthritis.

Osteoarthritis (OA) is a multifactorial and chronic disease describing the destruction of cartilage that can lead to defects in the elderly. There is currently no practical strategy that can reverse the OA process. Here, we describe nepetin, a small natural compound with extracellular matrix (ECM) and inflammation regulating functions. In this study, we investigated the therapeutic effects of nepetin on interleukin-1ß (IL-1ß)-induced inflammation in mice chondrocyte and OA model. In chondrocytes, treatment with nepetin inhibited the overexpression of pro-inflammatory cytokines and mediators induced by IL-1ß. Moreover, pretreatment or posttreatment with nepetin also reduced the ECM catabolism and enhanced the ECM anabolism. Mechanistically, nepetin suppressed NF-κB signaling pathway in IL-1ß stimulated chondrocyte. Meanwhile, our molecular docking studies indicated nepetin had a powerful binding capacity to p65. Furthermore, nepetin showed a protective and therapeutic effect on the mouse OA model. To sum up, this study indicated nepetin had a new potential therapeutic option in OA.

Acid Sphingomyelinase and Acid ß-Glucosidase 1 Exert Opposite Effects on Interleukin-1ß-Induced Interleukin 6 Production in Rheumatoid Arthritis Fibroblast-Like Synoviocytes.

Acid sphingomyelinase (ASM) and acid ß-glucosidase 1 (GBA1) catalyze ceramide formation through different routes, and both are involved in rheumatoid arthritis (RA) pathogenesis as well as IL-6 production. However, whether ASM and GBA1 regulate IL-6 production in RA remains unknown. Serum ASM, GBA1, and ceramide levels were measured in RA patients and healthy controls by enzyme-linked immunosorbent assay, and their correlations with clinical indicators of patients were evaluated. Pharmacologic inhibitors or small hairpin RNAs of ASM and GBA1 were employed to explore the roles of ASM and GBA1 in IL-6 production, cell behavior, and MAPK signaling in fibroblast-like synoviocytes from RA patients (RAFLS). ASM, GBA1, and ceramide serum levels were significantly elevated in patients with RA. GBA1 and ceramide serum levels were negatively and positively correlated with IL-6 serum level in RA patients, respectively. ASM inhibitor or knockdown of ASM abolished IL-1ß-induced IL-6 expression and secretion. Functionally, ASM inhibitor suppressed IL-1ß-induced cell proliferation, migration, and invasion in RAFLS. Mechanistically, ASM inhibitor or knockdown of ASM effectively countered IL-1ß-induced activation of p38 MAPK signaling. The pharmacologic inhibitor or knockdown of GBA1 exhibited the opposite effects. Importantly, p38 inhibitor blocked IL-1ß-induced IL-6 production in RAFLS. ASM plays a pathogenic role in RA, whereas GBA1 plays a protective role in RA possibly by regulating IL-6 production in RAFLS at least partially via p38 signaling, serving as potential therapeutic targets in RA treatment.

Ursolic acid ameliorates Nthy-ori 3-1 cells injury induced by IL-1ß through limiting MALAT1/miR-206/PTGS1 ceRNA network and NF-κB signaling pathway.

RATIONALE: Ursolic acid (UA) has exhibited anti-inflammatory and anti-oxidative drug effects. OBJECTIVES: In the research, we assessed the effects of UA on Nthy-ori 3-1 cells stimulated by IL-1ß and attempted to elucidate the mechanisms underlying the effects. METHODS: Autoimmune thyroiditis (AIT) was simulated using Nthy-ori 3-1 cells by IL-1ß (10 µM) treatment. UA (20 µM) was applied to ameliorate the injury of Nthy-ori 3-1 cells. The target of UA was predicted by TCMSP, BATMAN, and GEO database. Targeted relationship between lncRNA MALAT1 and miR-206, as well as miR-206 and PTGS1, was predicted by bioinformatics software and identified by dual luciferase assays. Cytokines in the cell supernatant and the apoptosis of cells were detected by ELISAs and flow cytometry assays, respectively. Expression levels of NF-κB signaling pathway-related proteins were estimated by western blot. RESULTS: By enquiring TCMSP, BATMAN, and GEO database, PTGS1 was identified as a target of UA. Afterward, a ceRNA network among MALAT1, miR-206, and PTGS1 was constructed. The expression levels of MALAT1 and PTGS1 in AIT tissues were obviously enhanced. Moreover, the ceRNA network formed by MALAT1/miR-206/PTGS1 contributed to the damage of Nthy-ori 3-1 cells induced by IL-1ß. However, UA ameliorated the Nthy-ori 3-1 cells injury induced by IL-1ß through mediating the MALAT1/miR-206/PTGS1 ceRNA network and NF-κB signaling pathway. CONCLUSIONS: UA treatment significantly relieved the injury of Nthy-ori 3-1 cells via inhibiting the ceRNA mechanism of MALAT1/miR-206/PTGS1 and inflammatory pathways, insinuating that UA may be helpful for the treatment of AIT.

Nimbolide exerts protective effects in complete Freund's adjuvant induced inflammatory arthritis via abrogation of STAT-3/NF-κB/Notch-1 signaling.

AIM: Activation of transmembrane Notch-1 receptors through inflammatory cytokines is highly regulated by STAT-3 and NF-κB phosphorylation. Nimbolide (NMB) exhibits potent anti-inflammatory, anti-fibrotic, anticancer activities by targeting various pathways. Here, we have investigated the effect of NMB in regulation of STAT-3/NF-κB/Notch-1 axis in complete Freund's adjuvant (CFA) induced inflammatory arthritis (IA) model. MAIN METHODS: The anti-inflammatory and anti-arthritic activity of NMB was evaluated both in vitro (IL-1ß stimulated HIG-82 synovial fibroblasts) and in vivo (CFA induced rat model of IA) models. In vitro anti-arthritic activity was assessed by anti-migratory effect, while in vivo effects were evaluated through radiological and histological analysis. The effect of NMB on STAT-3, NF-κB, Notch-1 signaling pathways and proinflammatory cytokines were studied using western blot, immunohistochemistry and ELISA methods. Key findings NMB attenuated the migration of synovial fibroblasts in vitro. It reduced the progression of arthritis as evidenced from the improved radiological and histological abnormalities in arthritic rats. NMB significantly suppressed the nitrosooxidative stress and levels of pro-inflammatory cytokines. NMB also exhibited remarkable protective activity against upregulation of MAPK, STAT-3 and NF-κB phosphorylation mediated Notch-1 signaling pathway in synovial tissue of arthritic rats. SIGNIFICANCE: NMB may have clinical therapeutic value in rheumatoid arthritis by inhibiting STAT-3/NF-κB/Notch-1 axis and also by reducing the levels of proinflammatory cytokines.

Hydrogen sulfide protects against IL-1ß-induced inflammation and mitochondrial dysfunction-related apoptosis in chondrocytes and ameliorates osteoarthritis.

The inflammatory environment and excessive chondrocyte apoptosis have been demonstrated to play crucial roles in the onset of osteoarthritis (OA). Hydrogen sulfide (H2 S), a gaseous signalling molecule, exerts an inhibitory effect on inflammation and apoptosis in several degenerative diseases. However, the protective effect of H2 S against OA has not been fully clarified, and its underlying mechanism should be examined further. In the current study, the role of endogenous H2 S in the pathogenesis of OA and its protective effects on interleukin (IL)-1ß-induced chondrocytes were identified. Our data revealed decreased H2 S expression in both human degenerative OA cartilage tissue and IL-1ß-induced chondrocytes. Pretreatment with the H2 S donor sodium hydrosulfide (NaHS) dramatically attenuated IL-1ß-induced overproduction of inflammatory cytokines and improved the balance between anabolic and catabolic chondrocyte capacities, and these effects were dependent on PI3K/AKT pathway-mediated inhibition of nuclear factor kappa B (NF-κB). Moreover, mitochondrial dysfunction-related apoptosis was significantly reversed by NaHS in IL-1ß-stimulated chondrocytes. Mechanistically, NaHS partially suppressed IL-1ß-induced phosphorylation of the mitogen-activated protein kinase (MAPK) cascades. Furthermore, in the destabilization of the medial meniscus mouse model, OA progression was ameliorated by NaHS administration. Taken together, these results suggest that H2 S may antagonize IL-1ß-induced inflammation and mitochondrial dysfunction-related apoptosis via selective suppression of the PI3K/Akt/NF-κB and MAPK signalling pathways, respectively, in chondrocytes and may be a potential therapeutic agent for the treatment of OA.

Oxyresveratrol Inhibits IL-1ß-Induced Inflammation via Suppressing AKT and ERK1/2 Activation in Human Microglia, HMC3.

Oxyresveratrol (OXY), a major phytochemical component derived from several plants, has been proved to have several pharmacological properties. However, the role of OXY in regulating neuroinflammation is still unclear. Here, we focused mainly on the anti-neuroinflammatory effects at the cellular level of OXY in the interleukin-1 beta (IL-1ß)-stimulated HMC3 human microglial cell line. We demonstrated that OXY strongly decreased the release of IL-6 and MCP-1 from HMC3 cells stimulated with IL-1ß. Nevertheless, IL-1ß could not induce the secretion of TNF-α and CXCL10 in this specific cell line, and that OXY did not have any effects on reducing the basal level of these cytokines in the sample culture supernatants. The densitometry analysis of immunoreactive bands from Western blot clearly indicated that IL-1ß does not trigger the nuclear factor-kappa B (NF-κB) signaling. We discovered that OXY exerted its anti-inflammatory role in IL-1ß-induced HMC3 cells by suppressing IL-1ß-induced activation of the PI3K/AKT/p70S6K pathway. Explicitly, the presence of OXY for only 4 h could strongly inhibit AKT phosphorylation. In addition, OXY had moderate effects on inhibiting the activation of ERK1/2. Results from immunofluorescence study further confirmed that OXY inhibited the phosphorylation of AKT and ERK1/2 MAPK upon IL-1ß stimulation in individual cells. These findings suggest that the possible anti-inflammatory mechanisms of OXY in IL-1ß-induced HMC3 cells are mainly through its ability to suppress the PI3K/AKT/p70S6K and ERK1/2 MAPK signal transduction cascades. In conclusion, our study provided accumulated data that OXY is able to suppress IL-1ß stimulation signaling in human microglial cells, and we believe that OXY could be a probable pharmacologic agent for altering microglial function in the treatment of neuroinflammation.

Geraniol-mediated osteoarthritis improvement by down-regulating PI3K/Akt/NF-κB and MAPK signals: In vivo and in vitro studies.

Osteoarthritis (OA) is a degenerative disease that has received increasing attention among the elderly. Its clinical manifestation is primarily long-term joint pain. Evidence for the pharmacological effects of geraniol in various diseases is accumulating. However, whether geraniol has a therapeutic effect against OA remains to be determined. In this study, we discussed the anti-inflammatory effects of geraniol in IL-1ß-induced chondrocytes and the anti-cartilage degradation effects in a mouse model of destabilization of the medial meniscus (DMM). In cell experiments, we found that the treatment of geraniol inhibited the expression of IL-1ß-induced PGE2, NO, COX-2, iNOS, TNF-α and IL-6 by western blot, qRT-PCR and immunofluorescence staining. Besides, geraniol inhibited the expression of MMP-9 and ADAMTS-5, and reversed the degradation of aggrecan and type II collagen. Mechanistically, we revealed that geraniol suppressed IL-1ß-stimulated PI3K/Akt/NF-κB and MAPK activation. Importantly, we have found in animal experiments that oral treatment of geraniol was beneficial in protecting articular cartilage from degradation. Overall, these data indicated that geraniol may have the potential to be developed as an effective treatment for OA.

Myricitrin regulates proliferation, apoptosis and inflammation of chondrocytes treated with IL-1ß.

Osteoarthritis (OA) is a clinical disease which seriously affects the quality of life of sufferers. Although the pathogenesis of OA has not been fully unraveled, it is may be due to increased levels of pro-inflammatory cytokines, activation of inflammation-related signaling pathways, and degradation of extracellular matrix. Osteoarthritis is characterized by chronic joint pain, swelling, stiffness, limited movement or joint deformity, all of which seriously affect the quality of life and health of the affected individuals. Myroside (Myr) is a polyphenolic hydroxyflavone glycoside extracted from the fruits, bark and leaves of myroside and other natural plants. It has many pharmacological properties, especially anti-inflammatory effects. In the present study, primary chondrocytes of IL-1ß rats were used to simulate pathological environment of chondrocytes in OA, and to explore the effect of Myr on chondrocytes. It was found that Myr improved the viability and proliferation of chondrocytes, and also inhibited apoptosis in these cells. Moreover, Myr reduced the expressions of inflammatory factors, and inhibited inflammatory reactions in chondrocytes. These findings provide good experimental basis for the clinical application of Myr in the prevention and treatment of progressive degeneration of cartilage in OA.

Imperatorin suppresses IL-1ß-induced iNOS expression via inhibiting ERK-MAPK/AP1 signaling in primary human OA chondrocytes.

Joint inflammation is a key player in the pathogenesis of osteoarthritis (OA). Imperatorin, a plant-derived small molecule has been reported to have anti-inflammatory properties; however, its effect on chondrocytes is not known. Here, we investigated the effects of Imperatorin on interleukin-1ß (IL-1ß) induced expression of inducible nitric oxide synthase (iNOS) and nitric oxide production in primary human OA chondrocytes and cartilage explants culture under pathological conditions and explored the associated signaling pathways. We pretreated chondrocytes or explants with Imperatorin (50 µM) followed by IL-1ß (1 ng/ml), and the culture supernatant was used to determine the levels of nitrite production by Griess assay and chondrocytes were harvested to prepare cell lysate or RNA for gene expression analysis of iNOS by Western blot or qPCR and in explants by immunohistochemistry (IHC). Pretreatment of primary chondrocytes and cartilage explants with Imperatorin suppressed IL-1ß induced expression of iNOS and NO production. Imperatorin blocked the IL-1ß-induced phosphorylation of ERK-MAPK/AP1 signaling pathway to suppress iNOS expression. The role of ERK in the regulation of iNOS expression was verified by using ERK inhibitor. Interestingly, we also found that Imperatorin binds to iNOS protein and inhibits its activity in vitro. Our data demonstrated that Imperatorin possess strong anti-inflammatory activity and may be developed as a therapeutic agent for the management of OA.

Suberoylanilide Hydroxamic Acid Attenuates Interleukin-1ß-Induced Interleukin-6 Upregulation by Inhibiting the Microtubule Affinity-Regulating Kinase 4/Nuclear Factor-κB Pathway in Synovium-Derived Mesenchymal Stem Cells from the Temporomandibular Joint.

Synovium-derived mesenchymal stem cells (SMSCs) can migrate to the site of destroyed condylar cartilage and differentiate into chondrocytes to repair temporomandibular joint (TMJ) damage. Interleukin (IL)-1ß-induced IL-6 secretion has been shown to inhibit the chondrogenic potential of SMSCs. The histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) has recently been shown to be closely related to the inflammation induced by IL-1ß. However, the relationship between SAHA and IL-6 secretion induced by IL-1ß in SMSCs remains unclear. In this study, we evaluated the relationships between IL-1ß and IL-6 in synovial specimens from patients with TMD and in model rats with osteoarthritis (OA). We found that IL-1ß and IL-6 were positively correlated and that IL-6 expression in SMSCs increased with IL-1ß stimulation in vitro. Moreover, microtubule affinity-regulating kinase 4 (MARK4) was significantly upregulated in IL-1ß-stimulated SMSCs and in the synovium of rats with OA. MARK4 knockdown inhibited IL-6 secretion and nuclear factor (NF)-κB pathway activation in IL-1ß-stimulated SMSCs. SAHA attenuated IL-6 secretion in IL-1ß-induced SMSCs through NF-κB pathway inhibition, and MARK4 was also downregulated in SAHA-treated SMSCs. However, inhibition of the NF-κB pathway did not suppress MARK4 expression. Thus, these results showed that SAHA attenuated IL-6 secretion in IL-1ß-induced SMSCs through inhibition of the MARK4/NF-κB pathway.

Nanosome-Mediated Delivery Of Protein Kinase D Inhibitor Protects Chondrocytes From Interleukin-1ß-Induced Stress And Apoptotic Death.

BACKGROUND: Inflammatory stress caused by protein kinase D (PKD) plays a critical role in damaging chondrocytes and extracellular matrix (ECM) during osteoarthritis (OA). The PKD inhibitor (PKDi) (CRT0066101) has been used to overcome inflammation in different cell types. However, the efficacy of a therapeutic drug can be limited due to off-target distribution, slow cellular internalization, and limited lysosomal escape. In order to overcome this issue, we developed nanosomes carrying CRT0066101 (PKDi-Nano) and tested their efficacy in vitro in chondrocytes. METHODS: Chondrocytes were subjected to IL-1ß-induced inflammatory stress treated with either PKDi or PKDi-Nano. Effects of treatment were measured in terms of cytotoxicity, cellular morphology, viability, apoptosis, phosphorylation of protein kinase B (Akt), and anabolic/catabolic gene expression analyses related to cartilage tissue. RESULTS AND DISCUSSION: The effects of PKDi-Nano treatment were more pronounced as compared to PKDi treatment. Cytotoxicity and apoptosis were significantly reduced following PKDi-Nano treatment (P < 0.001). Cellular morphology was also restored to normal size and shape. The viability of chondrocytes was significantly enhanced in PKDi-Nano-treated cells (P < 0.001). The data indicated that PKDi-Nano acted independently of the Akt pathway. Gene expression analyses revealed significant increases in the expression levels of anabolic genes with concomitant decreases in the level of catabolic genes. Our results indicate that PKDi-Nano attenuated the effects of IL-1ß via the nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) pathway. CONCLUSION: Taken together, these results suggest that PKDi-Nano can be used as a successful strategy to reduce IL1ß-induced inflammatory stress in chondrocytes.

Lycium barbarum polysaccharide alleviates IL-1ß-evoked chondrogenic ATDC5 cell inflammatory injury through mediation of microRNA-124.

Background: Lycium barbarum polysaccharide (LBP) is a promising therapeutic drug in inflammation-related injuries, nevertheless the mechanism of LBP's action is still elusive. The study is to explore the effect of LBP on IL-1ß-evoked ATDC5 cell inflammatory injury. Methods: ATDC5 cells were administrated with 10 ng/mL interleukin (IL)-1ß to establish an in vitro model of cartilage damage. After management, cell viability was tested through CCK8 assay. The pro-inflammatory cytokines and cyclooxygenase (Cox)-2 were assessed through ELISA, western blot and qRT-PCR. MiR-124 expression in ATDC5 cells was silenced by transfecting with miR-124 inhibitor, and the pro-inflammatory cytokines and Cox-2 were re-assessed. NF-κB and JNK pathways were measured through western blot. Results: IL-1ß stimulation accelerated the release of IL-1ß, IL-6 and TNF-α, elevated Cox-2 expression. LBP significantly eased IL-1ß-induced inflammation. MiR-124 expression was observed to enhance by LBP, and the impacts of LBP on ATDC5 cells were lightened via transfection with miR-124 inhibitor. NF-κB and JNK pathways were activated after IL-1ß stimulation, nevertheless were inactivated by LBP administration. Besides, LBP-evoked the repression of NF-κB and JNK pathways were overturned by miR-124 inhibitor. Conclusions: Our study suggests that LBP protects ATDC5 cells from IL-1ß-evoked injury through up-regulating miR-124 via blocking NF-κB and JNK pathways.