Dihydrolipoic acid suppresses ferroptosis in chondrocytes to ameliorate the progression of osteoarthritis by modulating the FOXO1/TXNIP signaling pathway.

Objective: The aim of this work was to determine the effect of miR-375 on chondrocyte metabolism and oxidative stress in osteoarthritis (OA) mouse models through the JAK2/STAT3 signaling pathway. Methods: Chondrocytes were divided into control, IL-1β, IL-1β + miR-375 mimic, IL-1β + miR-375 inhibitor, IL-1β + miR-NC (negative control), and IL-1β + miR-375 inhibitor + siJAK2 groups. The chondrocyte proliferation was determined by MTT assay, the superoxide dismutase (SOD) and malondialdehyde (MDA) levels by corresponding kits, and the chondrocyte apoptosis by TUNEL staining. Furthermore, OA mouse models were divided into Sham, OA + miR-NC, and OA + miRNA-375 antagomir groups. The pathological changes were observed, and the expressions of miR-375 and the JAK2/STAT3 pathway were determined by qRT-PCR and Western blotting, respectively. Results: IL-1β-induced chondrocytes had significant increases in miR-375 and MDA, with decreased proliferation and SOD levels, as compared to the control group. Meanwhile, they also exhibited elevated apoptosis, with upregulations of ADAMTS-5 and MMP-13 and downregulations of COL2A1 and ACAN, as well as decreased p-JAK2/JAK2, p-STAT3/STAT3, and Bcl-2/Bax. However, these changes were significantly improved after transfection with miR-375 inhibitor, but transfection with miR-375 mimic resulted in severer exacerbation. Notably, the improvement of miR-375 inhibitor could be abolished by transfection with siJAK2. Furthermore, miR-375 antagomir significantly alleviated OA progression in OA mice in vivo. Conclusion: MiR-375 suppression enhanced the ability of chondrocyte to antagonize the oxidative stress and maintained the homeostasis of extracellular matrix metabolism to protect chondrocytes from OA via activation of the JAK2/STAT3 pathway, indicating that miR-375 is a potential molecular target for OA treatment.

Osteoarthritis (OA) is a joint disease closely related to aging and characterized by degeneration of articular cartilage. Robinin is a natural agent with various pharmacological properties. Recently, Robinin has been found to have the potential to improve the bone-related diseases. However, its effect on OA development remained unknown. Here, we discuss the specific role and underlying mechanisms of Robinin in interleukin-1beta (IL-1β)-treated chondrocytes and OA mouse model. Chondrocytes were isolated from the mouse to conduct in vitro assays. We evaluated cell viability and apoptosis using Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis, respectively. Western blotting assessed the levels of proteins related to apoptosis, extracellular matrix (ECM), and signaling pathways. Immunofluorescence staining was used to detect the expression of ECM and signaling markers. ELISA was conducted to assess the levels of inflammatory markers. The OA mice model was established using surgical destabilization of the medial meniscus (DMM), and then H&E staining and Safranin O staining were conducted to observe the histopathological changes in synovial tissues. TUNEL assay was used to detect cell apoptosis in vivo. Real-time RT-PCR was operated to measure mRNA level in vitro and in vivo. We discovered that Robinin reversed the IL-1β-induced decrease in chondrocyte viability. Robinin suppressed IL-1β-induced apoptosis of chondrocytes. The ECM destruction and inflammatory response induced by IL-1β were markedly reversed by Robinin incubation in the mouse chondrocytes. Besides, the upregulated cytokine mRNA levels in IL-1β-treated chondrocytes were reduced by Robinin treatment. The downregulation of COL2A1 level and upregulation of MMP13 and ADAMTS5 levels were counteracted by Robinin treatment. Robinin reduced the protein levels of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) but enhanced the level of phosphorylated p65 (p-p65) in IL-1β-stimulated chondrocytes and OA mice. Robinin mitigated inflammation, cell apoptosis and cartilage destruction in synovial tissues from the OA mice. In conclusion, Robinin alleviated OA development in vitro and in vivo via TLR2/TLR4/NF-κB signaling pathway.

BackgroundThe transforming growth factor-beta (TGF-β) signaling pathway is an important pathway associated with the pathogenesis of osteoarthritis (OA). This study was to investigate the involvement of circRNAs in the TGF-β signaling pathway.MethodsCell Counting Kit-8 (CCK-8) assay and 5-ethynyl-2′-deoxyuridine (EdU) assay were used to detect the proliferation of primary mouse chondrocytes (PMCs). RNA-sequencing together with bioinformatics analysis were used to systematically clarify TGF-β1 induced alternations of circRNAs in PMCs. The regulatory and functional role of circPhf21a was examined in PMCs. Downstream targets of circPhf21a were explored by RNA-sequencing after overexpression of circPhf21a and verified by RT-qPCR in PMCs. Finally, the role and mechanism of circPhf21a in OA were explored in mouse models.ResultsWe found that TGF-β1 promoted the proliferation of PMCs. Meanwhile, RT-qPCR and western blotting indicated that TGF-β1 promoted extracellular matrix (ECM) anabolism. RNA-sequencing revealed that a total of 36 circRNAs were differentially expressed between PMCs treated with and without TGF-β1. Of these, circPhf21a was significantly decreased by TGF-β1. Furthermore, circPhf21a knockdown promoted the proliferation and ECM synthesis of PMCs, whereas overexpression of circPhf21a showed the opposite effects. Mechanically, the expression profiles of the mRNAs revealed that Vegfa may be the target of circPhf21a. Additionally, we found that circPhf21a was significantly upregulated in the mouse OA model, and inhibition of circPhf21a significantly relieved the progression of OA.ConclusionsOur results found that TGF-β1 promoted the proliferation and ECM synthesis of PMCs via the circPhf21a-Vegfa axis, which may provide novel therapeutic targets for OA treatment.D41VJr9_D9Fjp__yvtyWkzVideo abstract

Osteoarthritis (OA) is a common joint disease characterized by articular cartilage degeneration, with subchondral bone sclerosis being a key pathological change. However, the mechanism underlying subchondral bone sclerosis remains unclear. Senescent stem cells have been found in OA cartilage, synovium, and subchondral bone. This study aimed to explore the role of senescent bone marrow mesenchymal stem cells (BMSCs) in subchondral bone sclerosis and OA progression. This study utilized two mouse OA models: closed anterior cruciate ligament transection and spontaneous OA. Immunostaining was performed to assess the proportion of senescent cells especially BMSCs in subchondral bone during OA progression. A senescence model of BMSCs was constructed using H₂O₂, and transcriptomic sequencing was conducted to analyze secretory phenotypic changes in senescent BMSCs. In vitro experiments were performed to evaluate the effects of senescent BMSC-derived senescence-associated secretory phenotype (SASP) on osteogenic differentiation and osteogenic marker expression in normal BMSCs. We examined the mRNA expression of core molecules in osteogenesis-related pathways, which were activated by SASP. Additionally, OA mice were administered the senolytic combination of dasatinib and quercetin (D + Q), and its effects on senescent BMSCs, osteocalcin expression, subchondral bone sclerosis, and OA progression were assessed. Immunostaining results showed a significant increase in the proportion of senescent BMSCs in subchondral bone during OA progression. Transcriptomic sequencing revealed that senescent BMSCs acquired the SASP. In vitro experiments demonstrated that conditioned medium from senescent BMSCs (containing SASP) significantly promoted osteogenic differentiation and upregulated the expression of osteogenic markers in normal BMSCs. The SASP significantly upregulated Mapk8 and Mapk14 mRNAs in osteogenesis-related pathways. Administration of D + Q to OA mice effectively cleared senescent BMSCs, reduced osteocalcin expression in subchondral bone, inhibited subchondral bone sclerosis, and alleviated OA progression. This study indicates that senescent BMSCs promote subchondral bone sclerosis and OA progression through activating Mapk8 and Mapk14 via SASP in subchondral bone. The senolytic combination D + Q holds potential for OA treatment by eliminating senescent BMSCs in subchondral bone.

Non-invasive mouse models of post-traumatic 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-1β (IL-1β)-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-1β. 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-1β 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.

Soufeng Sanjie formula and its active ingredient formononetin alleviate osteoarthritis via PPARG-AKT-ERK1/2 promoted cartilage extracellular matrix anabolism.

Osteoarthritis (OA) is the most common joint disease in the elderly, characterized by cartilage degradation and proliferation of subchondral bone. The pathogenesis of OA involves a variety of inflammatory mediators, including nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. From the molecular mechanism, the nuclear factor-erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway and the expression of ROS regulated the production of the above inflammatory mediators. Saikosaponin D (SSD), which is an active ingredient isolated from Bupleurum, has various biological functions. In this study, IL-1β was used as a pro-inflammatory factor to create an in vitro OA model. According to the results of high-density culture, qPCR, ROS measurement, Western blot, and immunofluorescence, SSD activated the Nrf2/HO-1/ROS axis, inhibited the production of inflammatory mediators, and protected against ECM destruction. The DMM mouse model was used as a model of OA in mice. From the results of safranin O/fast green staining, hematoxylin–eosin staining, tartrate-resistant acid phosphatase (TRAP) staining, and OARSI scores, SSD protected against the mice knee articular cartilage degeneration and reduced the number of osteoclasts in the subchondral bone. Experimental results found that SSD suppressed IL-1β–induced differentiated ATDC 5 chondrocytes apoptosis via the Nrf2/HO-1/ROS axis in vitro. SSD delayed the progression of OA in DMMs model mice in vivo. Therefore, SSD has the potential to become a drug for clinical treatment of OA.

A role for CC-chemokine receptor 7 (CCR7) in a murine model of osteoarthritis: Impact on joint structure and function

Gel@CAT-L hydrogel mediates mitochondrial unfolded protein response to regulate reactive oxygen species and mitochondrial homeostasis in osteoarthritis.

Bone–cartilage interface crosstalk in osteoarthritis: potential pathways and future therapeutic strategies

Gait analyses of surgically induced osteoarthritis model mice by motion capture system

ObjectiveTo develop and validate an in vivo image acquisition protocol for assessment of cartilage degeneration in an osteoarthritis (OA) mouse model using contrast-enhanced micro-computed tomography (CECT).DesignThree-, four-, seven-, and 10-month-old male STR/ort OA (n = 8) and healthy control CBA/1 (n = 8) mice were imaged using synchrotron-radiation micro-computed tomography. Mean attenuation of cartilage and mean attenuation difference between cartilage and contrast agent (mean Δ attenuation), to control for flux, were calculated and correlated to previously published cartilage parameters measured in the same mice. In a second experiment, C57Bl/6 mice underwent destabilization of medial meniscus (DMM) surgery or sham surgery. At 0 (n = 8 DMM), and 4 weeks (n = 10 DMM, n = 6 sham) post-surgery, mice were imaged using CECT. Mean attenuation and Osteoarthritis Research Society International (OARSI) score of cartilage were calculated, and mean attenuation and OARSI score were correlated.ResultsMean Δ attenuation of medial cartilage was lower in STR/ort OA mice compared to healthy control CBA/1 at 3-, 4-, 7-, and 10-months of age. Medial mean Δ attenuation was positively correlated to cartilage volume and thickness and negatively correlated with surface-to-volume ratio and Collins score. The mean attenuation and OARSI score of cartilage in DMM OA mice was higher than in sham controls in the medial tibia. Mean attenuation was positively correlated with OARSI score in the medial tibia.ConclusionsAn in vivo CECT imaging method was developed and validated. Mean attenuation is sensitive to cartilage degeneration in OA mouse models when imaged against a contrast agent as a background and using in vivo compatible image acquisition parameters.

Paeonol inhibits ACSL4 to protect chondrocytes from ferroptosis and ameliorates osteoarthritis progression

KLF10 is upregulated in osteoarthritis and inhibits chondrocyte proliferation and migration by upregulating Acvr1 and suppressing inhbb expression