Gubi Zhitong formula alleviates osteoarthritis in vitro and in vivo via regulating BNIP3L-mediated mitophagy.

BACKGROUND: Osteoarthritis (OA) is characterized by degeneration of articular cartilage, leading to joint pain and dysfunction. Gubi Zhitong formula (GBZTF), a traditional Chinese medicine formula, has been used in the clinical treatment of OA for decades, demonstrating definite efficacy. However, its mechanism of action remains unclear, hindering its further application. METHODS: The ingredients of GBZTF were analyzed and performed with liquid chromatography-mass spectrometry (LC-MS). 6 weeks old SD rats were underwent running exercise (25 m/min, 80 min, 0°) to construct OA model with cartilage wear and tear. It was estimated by Micro-CT, Gait Analysis, Histological Stain. RNA-seq technology was performed with OA Rats' cartilage, and primary chondrocytes induced by IL-1ß (mimics OA chondrocytes) were utilized to evaluated and investigated the mechanism of how GBZTF protected OA cartilage from being damaged with some functional experiments. RESULTS: A total of 1006 compounds were identified under positive and negative ion modes by LC-MS. Then, we assessed the function of GBZTF through in vitro and vivo. It was found GBZTF could significantly up-regulate OA rats' limb coordination and weight-bearing capacity, and reduce the surface and sub-chondral bone erosions of OA joints, and protect cartilage from being destroyed by inflammatory factors (iNOS, IL-6, IL-1ß, TNF- α, MMP13, ADAMTS5), and promote OA chondrocytes proliferation and increase the S phage of cell cycle. In terms of mechanism, RNA-seq analysis of cartilage tissues revealed 1,778 and 3,824 differentially expressed genes (DEGs) in model vs control group and GBZTF vs model group, respectively. The mitophagy pathway was most significantly enriched in these DEGs. Further results of subunits of OA chondrocytes confirmed that GBZTF could alleviate OA-associated inflammation and cartilage damage through modulation BCL2 interacting protein 3-like (BNIP3L)-mediated mitophagy. CONCLUSION: The therapeutic effectiveness of GBZTF on OA were first time verified in vivo and vitro through functional experiments and RNA-seq, which provides convincing evidence to support the molecular mechanisms of GBZTF as a promising therapeutic decoction for OA.

Cyaonoside A-loaded composite hydrogel microspheres to treat osteoarthritis by relieving chondrocyte inflammation.

Cyaonoside A (CyA), derived from the natural Chinese medicine, Cyathula officinalis Kuan, which was for a long time used to treat knee injuries and relieve joint pain in traditional Chinese medicine, showed an unclear mechanism for protecting cartilage. In addition, CyA was poorly hydrosoluble and incapable of being injected directly into the joint cavity, which limited its clinical application. This study reveals that CyA resisted IL-1ß-mediated chondrogenic inflammation and apoptosis. Next, transcriptome sequencing is used to explore the potential mechanisms underlying CyA regulation of MSC chondrogenic differentiation. Based on these findings, CyA-loaded composite hydrogel microspheres (HLC) were developed and they possessed satisfactory loading efficiency, a suitable degradation rate and good biocompatibility. HLC increased chondrogenic anabolic gene (Acan, COL2A, and SOX9) expression, while downregulating the expression of the catabolic marker MMP13 in vitro. In the osteoarthritis mouse model, HLC demonstrated promising therapeutic capabilities by protecting the integrity of articular cartilage. In conclusion, this study provides insights into the regulatory mechanisms of CyA for chondrocytes and proposes a composite hydrogel microsphere-based advanced therapeutic strategy for osteoarthritis.

Protective Effects of Glycine soja Leaf and Stem Extract against Chondrocyte Inflammation and Osteoarthritis.

Wild soybean, also known as Glycine soja Sieb. et Zucc. (GS), has long been known for its various health benefits. Although various pharmacological effects of G. soja have been studied, the effects of GS leaf and stem (GSLS) on osteoarthritis (OA) have not been evaluated. Here, we examined the anti-inflammatory effects of GSLS in interleukin-1ß (IL-1ß)-stimulated SW1353 human chondrocytes. GSLS inhibited the expression of inflammatory cytokines and matrix metalloproteinases and ameliorated the degradation of collagen type II in IL-1ß-stimulated chondrocytes. Furthermore, GSLS played a protective role in chondrocytes by inhibiting the activation of NF-κB. In addition, our in vivo study demonstrated that GSLS ameliorated pain and reversed cartilage degeneration in joints by inhibiting inflammatory responses in a monosodium iodoacetate (MIA)-induced OA rat model. GSLS remarkably reduced the MIA-induced OA symptoms, such as joint pain, and decreased the serum levels of proinflammatory mediators, cytokines, and matrix metalloproteinases (MMPs). Our findings show that GSLS exerts anti-osteoarthritic effects and reduces pain and cartilage degeneration by downregulating inflammation, suggesting that it is a useful therapeutic candidate for OA.

Estrogen antagonizes ASIC1a-induced chondrocyte mitochondrial stress in rheumatoid arthritis.

BACKGROUND: Destruction of articular cartilage and bone is the main cause of joint dysfunction in rheumatoid arthritis (RA). Acid-sensing ion channel 1a (ASIC1a) is a key molecule that mediates the destruction of RA articular cartilage. Estrogen has been proven to have a protective effect against articular cartilage damage, however, the underlying mechanisms remain unclear. METHODS: We treated rat articular chondrocytes with an acidic environment, analyzed the expression levels of mitochondrial stress protein HSP10, ClpP, LONP1 by q-PCR and immunofluorescence staining. Transmission electron microscopy was used to analyze the mitochondrial morphological changes. Laser confocal microscopy was used to analyze the Ca2+, mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) level. Moreover, ASIC1a specific inhibitor Psalmotoxin 1 (Pctx-1) and Ethylene Glycol Tetraacetic Acid (EGTA) were used to observe whether acid stimulation damage mitochondrial function through Ca2+ influx mediated by ASIC1a and whether pretreatment with estrogen could counteract these phenomena. Furthermore, the ovariectomized (OVX) adjuvant arthritis (AA) rat model was treated with estrogen to explore the effect of estrogen on disease progression. RESULTS: Our results indicated that HSP10, ClpP, LONP1 protein and mRNA expression and mitochondrial ROS level were elevated in acid-stimulated chondrocytes. Moreover, acid stimulation decreased mitochondrial membrane potential and damaged mitochondrial structure of chondrocytes. Furthermore, ASIC1a specific inhibitor PcTx-1 and EGTA inhibited acid-induced mitochondrial abnormalities. In addition, estrogen could protect acid-stimulated induced mitochondrial stress by regulating the activity of ASIC1a in rat chondrocytes and protects cartilage damage in OVX AA rat. CONCLUSIONS: Extracellular acidification induces mitochondrial stress by activating ASIC1a, leading to the damage of rat articular chondrocytes. Estrogen antagonizes acidosis-induced joint damage by inhibiting ASIC1a activity. Our study provides new insights into the protective effect and mechanism of action of estrogen in RA.

Integration of a miniaturized DMMB assay with high-throughput screening for identifying regulators of proteoglycan metabolism.

Defective biosynthesis or function of proteoglycans causes pathological conditions in a variety of tissue systems. Osteoarthritis (OA) is a prevalent degenerative joint disorder characterized by progressive cartilage destruction caused by imbalanced proteoglycan synthesis and degradation. Identifying agents that regulate proteoglycan metabolism may benefit the development of OA-modifying therapeutics. High-throughput screening (HTS) of chemical libraries has paved the way for achieving this goal. However, the implementation and adaptation of HTS assays based on proteoglycan measurement remain underexploited. Using primary porcine chondrocytes as a model, we report a miniaturized dimethyl-methylene blue (DMMB) assay, which is commonly used to quantitatively evaluate sulfated glycosaminoglycan (GAG) content, with an optimized detection range and reproducibility and its integration with HTS. Treatment with TGF-ß1 and IL1-α, known as positive and negative proteoglycan regulators, respectively, supported the assay specificity. A pre-test of chemical screening of 960 compounds identified both stimulators (4.48%) and inhibitors (6.04%) of GAG production. Fluorophore-assisted carbohydrate electrophoresis validated the activity of selected hits on chondroitin sulfate expression in an alginate culture system. Our findings support the implementation of this simple colorimetric assay in HTS to discover modifiers of OA or other diseases related to dysregulated proteoglycan metabolism.

Ononin ameliorates inflammation and cartilage degradation in rat chondrocytes with IL-1ß-induced osteoarthritis by downregulating the MAPK and NF-κB pathways.

BACKGROUND: Osteoarthritis (OA) treatment aims to improve inflammation and delay cartilage degeneration. However, there is no effective strategy presently available. Ononin, a representative isoflavone glycoside component extracted from natural Chinese herbs, exerts anti-inflammatory and proliferative effects. However, the therapeutic effect of ononin on chondrocyte inflammation remains unclear. METHODS: In this study, we explored the therapeutic effect and potential mechanism of ononin in OA by establishing an interleukin-1 beta (IL-1ß)-induced chondrocyte inflammation model. RESULTS: Our results verified that ononin alleviated the IL-1ß-induced decrease in chondrocyte viability, attenuated the overexpression of the inflammatory factors tumour necrosis factor α (TNF-α) and interleukin 6 (IL-6), and simultaneously inhibited the expression of cartilage extracellular matrix (ECM)-degrading enzymes such as matrix metalloproteinase-13 (MMP-13). Furthermore, the decomposition of Collagen II protein could be alleviated in the OA model by ononin. Finally, ononin improved chondrocyte inflammation by downregulating the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signalling pathways. CONCLUSION: Our findings suggested that ononin could inhibit the IL-1ß-induced proinflammatory response and ECM degradation in chondrocytes by interfering with the abnormal activation of the MAPK and NF-κB pathways, indicating its protective effect against OA.

Prenylated phenolic compounds from licorice (Glycyrrhiza uralensis) and their anti-inflammatory activity against osteoarthritis.

Osteoarthritis is a significant driver of disability in the elderly with increasing prevalence, and inflammation plays a vital role on its etiology. Licorice is commonly used as a traditional Chinese medicine or food additive, and its prenylated phenolic compounds were recently reported to be able to inhibit osteoarthritis with anti-inflammatory activity. In order to explore more anti-osteoarthritic prenylated phenolic compounds from licorice, we isolated ten compounds (1-10), with three new ones (1-3), from the ethyl acetate extract of Glycyrrhiza uralensis. Compound 2 (glycyuralin R) was a racemic 3-phenoxy-chromanone, and we achieved its chiral separation for the first time. Compounds 1, 2, 7 and 8 showed significant NO inhibitory ability in IL-1ß-stimulated mouse primary chondrocytes, and we further confirmed the anti-inflammatory activity of 1 (glycyuralin Q) by evaluating its effect on osteoarthritis-related iNOS, COX-2, TNF-α, IL-6, MMP3, MMP13 and NF-κB based on various experimental methods. These results clarified the potential of several prenylated phenolic compounds, especially 1 in licorice, as the lead compounds for osteoarthritis.

Compatibility of Achyranthes bidentata components in reducing inflammatory response through Arachidonic acid pathway for treatment of Osteoarthritis.

Achyranthes bidentate is a common traditional Chinese medicine (TCM) used in treating osteoarthritis (OA). The compatibility between effective components has now become a breakthrough in understanding the mechanism of TCM. This study aimed at determining the optimal compatibility and possible mechanism of Achyranthes bidentate for OA treatment. Results showed that the adhesion score of the OA group is higher than NC group, and showed a trend of down-regulation in the intervention group. The CHI3L1 and IL-1ß in joint fluid of the OA group was significantly increased compared to the sham operation group (NC group). Group G, I, and L exhibited significantly down-regulated CHI3L1, while groups C, F, I, K, and L exhibited reduced IL-1ß. Joint adhesion, damage in cartilage, and synovial tissue was found in the OA model, cartilage tissue was found recovered in groups I, J, and L, and synovial tissue was recovered in group G, I, and L. Thus, group I and L were chosen for metabolite analysis, and indole-3-propionic acid was slightly up-regulated, while koeiginequinone A, prostaglandin H2, and 1-hydroxy-3-methoxy-10-methylacridonew were down-regulated in group I and L. According to functional analysis, the arachidonic acid (AA) metabolic pathway is enriched. Down-regulated expression of vital proteins in the AA metabolism pathway, such as PGE2 and COX2 in group I and L were verified. In conclusion, Hydroxyecdysone, Oleanolic acid, Achyranthes bidentata polysaccharide at a compatibility of 0.03-µg/mg, 2.0-µg/mg, 20.0-µg/mg or 0.03-µg/mg, 2.0-µg/mg, 10.0-µg/mg, respectively, may be the optimal compatibility of Achyranthes bidentate.

Caviunin glycoside (CAFG) from Dalbergia sissoo attenuates osteoarthritis by modulating chondrogenic and matrix regulating proteins.

ETHNOPHARMACOLOGICAL RELEVANCE: Dalbergia sissoo DC. (Indian rosewood or Sheesham) is a traditional medicinal plant, reported since time immemorial for its analgesic, anti-nociceptive, anti-inflammatory, and immuno-modulatory properties. D. sissoo DC (DS). is being used traditionally to cure joint inflammation and joint pain. AIM: To study the potential of DS leaves and its derived novel compound CAFG to treat the clinical symptoms of osteoarthritis (OA) and its underlying mechanism. METHODS: The chemical profile of DS extract (DSE) with isoflavonoids and isoflvaonoid glycosides from the DS was established by UHPLC-PDA and UHPLC-MS/MS. Monosodium iodoacetate (MIA) was injected into the knee joint to develop the OA model in rats. DSE was given orally for 28 days daily at 250 and 500 mg.kg-1day-1. For in-vitro experiments, chondrocytes isolated from joint articular cartilage were negatively induced with interleukin-1ß (IL-1ß) and CAFG was given to the cells as a co-treatment. RESULTS: Chondrocytes undergo apoptosis following inflammation and proteoglycan synthesis affected in MIA injected knees. DSE administration prevented these effects as assessed by H&E and Toluidine blue staining. Micro-CT analysis showed that subchondral bone loss was restored. DSE decreased elevated serum levels of cartilage-bone degradation (CTX-I, CTX-II, and COMP), inflammation markers IL-1ß, and matrix-degrading MMP-3 and 13. The effects of IL-1ß on gene expression of chondrocytes were reversed by CAFG treatment at 1 µM. CONCLUSION: Data showed that DSE protected joint cartilage and deterioration in subchondral bone in vivo while in in-vitro, its active ingredient CAFG prevented interleukin-1ß induced effects and inhibited OA. This finding suggest that DSE and CAFG could be used as a possible therapeutic to treat osteoarthritis.

Engineering osteoarthritic cartilage model through differentiating senescent human mesenchymal stem cells for testing disease-modifying drugs.

Significant cellular senescence has been observed in cartilage harvested from patients with osteoarthritis (OA). In this study, we aim to develop a senescence-relevant OA-like cartilage model for developing disease-modifying OA drugs (DMOADs). Specifically, human bone marrow-derived mesenchymal stromal cells (MSCs) were expanded in vitro up to passage 10 (P10-MSCs). Following their senescent phenotype formation, P10-MSCs were subjected to pellet culture in chondrogenic medium. Results from qRT-PCR, histology, and immunostaining indicated that cartilage generated from P10-MSCs displayed both senescent and OA-like phenotypes without using other OA-inducing agents, when compared to that from normal passage 4 (P4)-MSCs. Interestingly, the same gene expression differences observed between P4-MSCs and P10-MSC-derived cartilage tissues were also observed between the preserved and damaged OA cartilage regions taken from human samples, as demonstrated by RNA Sequencing data and other analysis methods. Lastly, the utility of this senescence-initiated OA-like cartilage model in drug development was assessed by testing several potential DMOADs and senolytics. The results suggest that pre-existing cellular senescence can induce the generation of OA-like changes in cartilage. The P4- and P10-MSCs derived cartilage models also represent a novel platform for predicting the efficacy and toxicity of potential DMOADs on both preserved and damaged cartilage in humans.

Chlorogenic acid suppresses mitochondrial apoptotic effectors Bax/Bak to counteract Nod-like receptor pyrin domain 3 (NLRP3) inflammasome in thiram exposed chondrocytes.

BACKGROUND: Tibial dyschondroplasia (TD) is a common disease characterized by proliferation and the deterioration of growth plate's chondrocytes due to widespread utilization of thiram in the agriculture and industrial sector. PURPOSE: In recent years, Nod-like receptor pyrin domain 3 (NLRP3) inflammasome has become a dilemma in the occurrence of many diseases. According to many research investigations, NLRP3 inflammasome has been linked to various diseases caused by pesticides and environmental toxins. Its involvement in such conditions opens up new treatment approaches. However, the role of the NLRP3 inflammasome in the development of TD is not fully understood under the impact of chlorogenic acid (CGA). METHODS: Chondrocytes were cultured with our previously developed methodology from growth plates. After morphological and molecular identification, chondrocytes were split into different groups to investigate the efficacy of chlorogenic acid. Cell apoptosis was determined through flow cytometry and Tunnel assay. Furthermore, RT-qPCR, immunofluorescence, and western blotting techniques were used to check marker genes and proteins expression. RESULTS: In thiram-induced TD, Bax/Bak activation persuade a parallel pathway, mediated by the NLRP3 base inflammasome. It is worth mentioning that the apoptotic executioners (caspase-3 and caspase-7) act upstream for inflammasome. Furthermore, chondrocytes' ability to undergo mitochondrial apoptosis was governed by anti-apoptotic members, e.g., Bcl-2 and Bcl-xl. Equilibrium of these anti-apoptotic proteins ensured appropriate regulation of apoptosis during the development and survival of chondrocytes. CONCLUSION: Chondrocytes have ability to undergo Bax/Bak-mediated apoptosis and generate pro-inflammatory signals, e.g., NLRP3 in thiram-induced TD. So, the Nod-like receptor pyrin domain 3 is the potential target to eliminate TD at all stages of pathology, while drugs, e.g., CGA, can significantly improve chondrocytes' survival by targeting these pro-inflammatory signals.

In vitro effects of nutraceutical treatment on human osteoarthritic chondrocytes of females of different age and weight groups.

The in vitro effects of four nutraceuticals, catechin hydrate, gallic acid, α-tocopherol and ascorbic acid, on the ability of human osteoarthritic chondrocytes of two female obese groups to form articular cartilage (AC) tissues and to reduce inflammation were investigated. Group 1 represented thirteen females in the 50-69 years old range, an average weight of 100 kg and an average body mass index (BMI) of 34⋅06 kg/m2. Group 2 was constituted of three females in the 70-80 years old range, an average weight of 75 kg and an average BMI of 31⋅43 kg/m2. The efficacy of nutraceuticals was assessed in monolayer cultures using histological, colorimetric and mRNA gene expression analyses. AC engineered tissues of group 1 produced less total collagen and COL2A1 (38-fold), and higher COL10A1 (2⋅7-fold), MMP13 (50-fold) and NOS2 (15-fold) mRNA levels than those of group 2. In comparison, engineered tissues of group 1 had a significant decrease in NO levels from day 1 to day 21 (2⋅6-fold), as well as higher mRNA levels of FOXO1 (2-fold) and TNFAIP6 (16-fold) compared to group 2. Catechin hydrate decreased NO levels significantly in group 1 (1⋅5-fold) while increasing NO levels significantly in group 2 (3⋅8-fold). No differences from the negative control were observed in the presence of other nutraceuticals for either group. In conclusion, engineered tissues of the younger but heavier patients responded better to nutraceuticals than those from the older but leaner study participants. Finally, cells of group 2 formed better AC tissues with less inflammation and better extracellular matrix than cells of group 1.

Targeted treatment for osteoarthritis: drugs and delivery system.

The management of osteoarthritis (OA) is a clinical challenge due to the particular avascular, dense, and occluded tissue structure. Despite numerous clinical reports and animal studies, the pathogenesis and progression of OA are still not fully understood. On the basis of traditional drugs, a large number of new drugs have been continuously developed. Intra-articular (IA) administration for OA hastens the development of targeted drug delivery systems (DDS). OA drugs modification and the synthesis of bioadaptive carriers contribute to a qualitative leap in the efficacy of IA treatment. Nanoparticles (NPs) are demonstrated credible improvement of drug penetration and retention in OA. Targeted nanomaterial delivery systems show the prominent biocompatibility and drug loading-release ability. This article reviews different drugs and nanomaterial delivery systems for IA treatment of OA, in an attempt to resolve the inconsonance between in vitro and in vivo release, and explore more interactions between drugs and nanocarriers, so as to open up new horizons for the treatment of OA.

Avenanthramide C as a novel candidate to alleviate osteoarthritic pathogenesis.

Osteoarthritis (OA) is a degenerative disorder that can result in the loss of articular cartilage. No effective treatment against OA is currently available. Thus, interest in natural health products to relieve OA symptoms is increasing. However, their qualities such as efficacy, toxicity, and mechanism are poorly understood. In this study, we determined the efficacy of avenanthramide (Avn)-C extracted from oats as a promising candidate to prevent OA progression and its mechanism of action to prevent the expression of matrix-metalloproteinases (MMPs) in OA pathogenesis. Interleukin-1 beta (IL-1ß), a proinflammatory cytokine as a main causing factor of cartilage destruction, was used to induce OAlike condition of chondrocytes in vitro. Avn-C restrained IL-1ß- mediated expression and activity of MMPs, such as MMP-3, -12, and -13 in mouse articular chondrocytes. Moreover, Avn-C alleviated cartilage destruction in experimental OA mouse model induced by destabilization of the medial meniscus (DMM) surgery. However, Avn-C did not affect the expression of inflammatory mediators (Ptgs2 and Nos) or anabolic factors (Col2a1, Aggrecan, and Sox9), although expression levels of these genes were upregulated or downregulated by IL-1ß, respectively. The inhibition of MMP expression by Avn-C in articular chondrocytes was mediated by p38 kinase and c-Jun N-terminal kinase (JNK) signaling, but not by ERK or NF-κB. Interestingly, Avn-C added with SB203580 and SP600125 as specific inhibitors of p38 kinase and JNK, respectively, enhanced its inhibitory effect on the expression of MMPs in IL-1ß treated chondrocytes. Taken together, these results suggest that Avn-C is an effective candidate to prevent OA progression and a natural health product to relieve OA pathogenesis. [BMB Reports 2021; 54(10): 528-533].

Combining stretching and gallic acid to decrease inflammation indices and promote extracellular matrix production in osteoarthritic human articular chondrocytes.

Osteoarthritis (OA) patients undergo cartilage degradation and experience painful joint swelling. OA symptoms are caused by inflammatory molecules and the upregulation of catabolic genes leading to the breakdown of cartilage extracellular matrix (ECM). Here, we investigate the effects of gallic acid (GA) and mechanical stretching on the expression of anabolic and catabolic genes and restoring ECM production by osteoarthritic human articular chondrocytes (hAChs) cultured in monolayers. hAChs were seeded onto conventional plates or silicone chambers with or without 100 µM GA. A 5% cyclic tensile strain (CTS) was applied to the silicone chambers and the deposition of collagen and glycosaminoglycan, and gene expressions of collagen types II (COL2A1), XI (COL11A2), I (COL1A1), and X (COL10A1), and matrix metalloproteinases (MMP-1 and MMP-13) as inflammation markers, were quantified. CTS and GA acted synergistically to promote the deposition of collagen and glycosaminoglycan in the ECM by 14- and 7-fold, respectively. Furthermore, the synergistic stimuli selectively upregulated the expression of cartilage-specific proteins, COL11A2 by 7-fold, and COL2A1 by 47-fold, and, in contrast, downregulated the expression of MMP-1 by 2.5-fold and MMP-13 by 125-fold. GA supplementation with CTS is a promising approach for restoring osteoarthritic hAChs ECM production ability making them suitable for complex tissue engineering applications.

α-Cyperone (CYP) down-regulates NF-κB and MAPKs signaling, attenuating inflammation and extracellular matrix degradation in chondrocytes, to ameliorate osteoarthritis in mice.

Inflammation and extracellular matrix (ECM) degradation have been implicated in the pathological process of osteoarthritis (OA). α-Cyperone is the main active component of the traditional Chinese medicine Cyperus rotundus L. In this study, we found that α-Cyperone abolished the IL-1ß-induced production of inflammatory cytokines in isolated rat chondrocytes, such as cyclooxygenase-2 (COX-2), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS), in a dose-dependent manner (0.75, 1.5 or 3 µM). Also, the results showed that α-Cyperone downregulated the expression of metalloproteinases (MMPs) and thrombospondin motifs 5 (ADAMTS5), and upregulated the expression of type-2 collagen. Mechanistically, molecular docking tests revealed that α-Cyperone stably and effectively binds to p65, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK). α-Cyperone inhibited NF-κB activation by blocking its nuclear transfer, and decreasing the phosphorylation of mitogen-activated protein kinase (MAPKs). In addition, in vivo studies based on a mouse model of arthritis showed that α-Cyperone prevented the development of osteoarthritis. Therefore, α-Cyperone may be a potential anti-OA drug.

Pretreatment with mechano growth factor E peptide attenuates osteoarthritis through improving cell proliferation and extracellular matrix synthesis in chondrocytes under severe hypoxia.

Osteoarthritis (OA) is characterized by pain and declining gait function associated with degeneration of cartilage. A severe hypoxic environment occurs due to tissue injury in the joint cavity and may aggravate the development of OA. In this study, the effects of severe hypoxia and treatment with mechano growth factor (MGF) E peptide on metabolism of the extracellular matrix (ECM) during the progression of OA were determined. The results showed that cell viability, cell proliferation, and type II collagen expression in chondrocytes were significantly inhibited by cobalt chloride (CoCl2)-simulated severe hypoxia, whereas cell apoptosis and expression levels of hypoxia inducible factor 1 alpha, type I collagen, and matrix metalloproteinases 1/13 were clearly induced. Pretreatment with MGF E peptide reduced the abovementioned adverse effects induced by CoCl2-simulated severe hypoxia in chondrocytes. Pretreatment also upregulated the proliferation of chondrocytes under severe hypoxia through the PI3K-Akt and MEK-ERK1/2 signaling pathways. In a rat model of monosodium iodoacetate (MIA)-induced OA. MIA treatment induced tissue necrosis and cartilage degeneration, and histological score was significantly decreased. The levels of type II collagen and aggrecan were reduced after MIA treatment for 4 or 6 weeks, and abnormal distribution of ECM occurred in the inner epicondyle after 6 weeks. MGF E peptide also reduced the progression of MIA-induced OA by retarding cartilage degeneration, upregulating type II collagen synthesis, and improving ECM distribution after 4 or 6 weeks. Our findings suggest that MGF attenuates the progression of OA, and thus may be applied for the treatment of OA in the clinic.

Activation of autophagy contributes to the protective effects of lycopene against oxidative stress-induced apoptosis in rat chondrocytes.

Oxidative stress is commonly associated with osteoarthritis (OA). Lycopene (LYC), a natural carotenoid compound, is an effective antioxidant with potential cartilage-protecting actions. However, how it affects hydrogen peroxide (H2 O2 )-induced damage to the cartilage is unclear. In this study, an in vitro oxidative stress model was developed via treating primary chondrocytes with H2 O2 . Western blot, immunohistochemistry, and quantitative RT-PCR (qRT-PCR) were used to assess the levels of related factors. Reactive oxygen species (ROS) and apoptosis levels were analyzed by the use of appropriate probes and flow cytometry. The expression and activity of stress-specific enzymes (malondialdehyde, superoxide dismutase, and catalase) were also assessed. The role of autophagy was explored by using the inhibitor, 3-methyladenine (3-MA), as well as monodansylcadaverine staining, western blotting, and red fluorescent protein-green fluorescent protein-light chain 3 lentivirus infection. The result showed LYC exerted significant chondrocyte-protective effects, including reduced inflammation and chondrocyte degradation, increased chondrocyte proliferation, apoptosis inhibition, and reduced ROS production. LYC could effectively induce autophagy in the H2 O2 treatment group, and this effect could be attenuated by 3-MA. In terms of mechanism, LYC played a role in inhibiting MAPK and PI3K/Akt/NF-κB axis, which down-regulates levels of mTOR and had a potential therapeutic significance for cartilage degeneration.

Marine Collagen Hydrolysates Promote Collagen Synthesis, Viability and Proliferation While Downregulating the Synthesis of Pro-Catabolic Markers in Human Articular Chondrocytes.

Cartilage is a non-innervated and non-vascularized tissue. It is composed of one main cell type, the chondrocyte, which governs homeostasis within the cartilage tissue, but has low metabolic activity. Articular cartilage undergoes substantial stresses that lead to chondral defects, and inevitably osteoarthritis (OA) due to the low intrinsic repair capacity of cartilage. OA remains an incurable degenerative disease. In this context, several dietary supplements have shown promising results, notably in the relief of OA symptoms. In this study, we investigated the effects of collagen hydrolysates derived from fish skin (Promerim®30 and Promerim®60) and fish cartilage (Promerim®40) on the phenotype and metabolism of human articular chondrocytes (HACs). First, we demonstrated the safety of Promerim® hydrolysates on HACs cultured in monolayers. Then we showed that, Promerim® hydrolysates can increase the HAC viability and proliferation, while decreasing HAC SA-ß-galactosidase activity. To evaluate the effect of Promerim® on a more relevant model of culture, HAC were cultured as organoids in the presence of Promerim® hydrolysates with or without IL-1ß to mimic an OA environment. In such conditions, Promerim® hydrolysates led to a decrease in the transcript levels of some proteases that play a major role in the development of OA, such as Htra1 and metalloproteinase-1. Promerim® hydrolysates downregulated HtrA1 protein expression. In contrast, the treatment of cartilage organoids with Promerim® hydrolysates increased the neosynthesis of type I collagen (Promerim®30, 40 and 60) and type II collagen isoforms (Promerim®30 and 40), the latter being the major characteristic component of the cartilage extracellular matrix. Altogether, our results demonstrate that the use of Promerim® hydrolysates hold promise as complementary dietary supplements in combination with the current classical treatments or as a preventive therapy to delay the occurrence of OA in humans.

Antiosteoarthritic Effect of Morroniside in Chondrocyte Inflammation and Destabilization of Medial Meniscus-Induced Mouse Model.

Osteoarthritis (OA) is a common degenerative disease that results in joint inflammation as well as pain and stiffness. A previous study has reported that Cornus officinalis (CO) extract inhibits oxidant activities and oxidative stress in RAW 264.7 cells. In the present study, we isolated bioactive compound(s) by fractionating the CO extract to elucidate its antiosteoarthritic effects. A single bioactive component, morroniside, was identified as a potential candidate. The CO extract and morroniside exhibited antiosteoarthritic effects by downregulating factors associated with cartilage degradation, including cyclooxygenase-2 (Cox-2), matrix metalloproteinase 3 (Mmp-3), and matrix metalloproteinase 13 (Mmp-13), in interleukin-1 beta (IL-1ß)-induced chondrocytes. Furthermore, morroniside prevented prostaglandin E2 (PGE2) and collagenase secretion in IL-1ß-induced chondrocytes. In the destabilization of the medial meniscus (DMM)-induced mouse osteoarthritic model, morroniside administration attenuated cartilage destruction by decreasing expression of inflammatory mediators, such as Cox-2, Mmp3, and Mmp13, in the articular cartilage. Transverse microcomputed tomography analysis revealed that morroniside reduced DMM-induced sclerosis in the subchondral bone plate. These findings suggest that morroniside may be a potential protective bioactive compound against OA pathogenesis.