Osteoarthritis (OA) is a complicated joint disorder characterized by inflammation that causes joint destruction. Cucurbitacin B (CuB) is a naturally occurring triterpenoid compound derived from ...plants in the Cucurbitaceae family. The aim of this study is to investigate the potential role and mechanisms of CuB in a mouse model of OA. This study identified the key targets and potential pathways of CuB through network pharmacology analysis. In vivo and in vitro studies confirmed the potential mechanisms of CuB in OA. Through network pharmacology, 54 potential targets for CuB in treating OA were identified. The therapeutic potential of CuB is associated with the nod‐like receptor pyrin domain 3 (NLRP3) inflammasome and pyroptosis. Molecular docking results indicate a strong binding affinity of CuB to nuclear factor erythroid 2‐related factor 2 (Nrf2) and p65. In vitro experiments demonstrate that CuB effectively inhibits the expression of pro‐inflammatory factors induced by interleukin‐1β (IL‐1β), including cyclooxygenase‐2, inducible nitric oxide synthase, IL‐1β, and IL‐18. CuB inhibits the degradation of type II collagen and aggrecan in the extracellular matrix (ECM), as well as the expression of matrix metalloproteinase‐13 and a disintegrin and metalloproteinase with thrombospondin motifs‐5. CuB protects cells by activating the Nrf2/hemeoxygenase‐1 (HO‐1) pathway and inhibiting nuclear factor‐κB (NF‐κB)/NLRP3 inflammasome‐mediated pyroptosis. Moreover, in vivo experiments show that CuB can slow down cartilage degradation in an OA mouse model. CuB effectively prevents the progression of OA by inhibiting inflammation in chondrocytes and ECM degradation. This action is further mediated through the activation of the Nrf2/HO‐1 pathway to inhibit NF‐κB/NLRP3 inflammasome activation. Thus, CuB is a potential therapeutic agent for OA.
Intervertebral disc degeneration (IVDD) is a prevalent degenerative disease with significant adverse implications for patients' quality of life and socioeconomic status. Although the precise etiology ...of IVDD remains elusive, the senescence of nucleus pulposus cells is recognized as the primary pathogenic factor of IVDD; however, drugs that may targetedly inhibit senescence are still lacking. In the current study, we evaluated the small-molecule active drug 20-Deoxyingenol(20-DOI) for its effects on combating senescence and delaying the progression of IVDD. In vitro experiments revealed that the administration of 20-DOI displayed inhibitory effects on senescence and the senescence-related cGAS-STING pathway of nucleus pulposus cells. Additionally, it exhibited the ability to enhance lysosome activity and promote autophagy flux within nucleus pulposus cells. Subsequent investigations elucidated that the inhibitory impact of 20-DOI on nucleus pulposus cell senescence was mediated through the autophagy-lysosome pathway. This effect was diminished in the presence of transcription factor EB (TFEB) small hairpin RNA (shRNA), thereby confirming the regulatory role of 20-DOI on the autophagy-lysosome pathway and senescence through TFEB. In vivo experiments demonstrated that 20-DOI effectively impeded the progression ofIVDD in rats. These findings collectively illustrate that 20-DOI may facilitate the autophagy-lysosomal pathway by activating TFEB, thereby suppressing the senescence in nucleus pulposus cells, thus suggesting 20-DOI as a promising therapeutic approach for IVDD.
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•SM04690@ApoFn, a SM04690-loaded apoferritin nanocage, alleviates osteoarthritis by modulating the cartilage extracellular matrix and inhibiting ferroptosis, with targeted ...anti-inflammatory properties.•This study elucidates SM04690’s novel role in cartilage extracellular matrix regulation, marking the first investigation into its therapeutic mechanisms in osteoarthritis.•We explore the impact of IL-1β on iron metabolism in chondrocytes, highlighting apoferritin’s critical role in mitigating ferroptosis.•First to demonstrate that the transferrin receptor is upregulated in inflamed cartilage, supporting targeted inflammation therapy via SM04690@ApoFn through transferrin receptor mediation.
Osteoarthritis (OA) currently affects over 15% of the global population. However, OA management primarily focuses on symptom relief, with a lack of targeted and effective therapeutic strategies. SM04690 (Adavivint, Lorecivivint) represents a small molecule with promising potential as a novel agent for cartilage regeneration and pain relief in OA treatment, Phase III clinical trials are currently underway. This study explores its previously unexamined effects on regulating chondrocyte extracellular matrix (ECM) function. However, its targeted delivery to the inflammatory cells remains a challenge; also, ideal therapeutic agent for OA requires to be multi-functional, e.g. suppressing ferroptosis in chondrocytes. In the current study, we designed an ApoFerritin nanocage loaded with SM04690 (SM04690@ApoFn) for OA therapy. In vitro study showed that SM04690 may have chondro-regenerative effect similar to kartogenin (KGN) but works at much lower concentrations. SM04690@ApoFn demonstrated good biocompatibility both in vitro and in vivo. The following studies revealed that SM04690@ApoFn may effectively promote ECM metabolism in chondrocytes, it may also suppress ferroptosis; meanwhile, it may have the ability to targeting the inflammatory chondrocytes through binding to transferrin receptor (TfR). In vivo study demonstrated that SM04690@ApoFn may alleviate the progression of OA in mice. In conclusion, the multifunctional SM04690@ApoFn nanocage shows great potential for OA therapy by promoting ECM metabolism, suppressing ferroptosis and targeting inflammatory chondrocytes.
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Osteoarthritis (OA) is an age-related degenerative disease and currently cannot be cured. Transcription factor EB (TFEB) is one of the major transcriptional factors that regulates ...autophagy and lysosomal biogenesis. TFEB has been shown to be an effective therapeutic target for many diseases including OA. The current study explores the therapeutic effects of 20-Deoxyingenol (20-DOI) on OA as well as its working mechanism on TFEB regulation. The in vitro study showed that 20-DOI may suppress apoptosis and senescence induced by oxidative stress in chondrocytes; it may also promote the nuclear localization of TFEB in chondrocytes. Knock-down of TFEB compromised the effects of 20-DOI on apoptosis and senescence. The in vivo study demonstrated that 20-DOI may postpone the progression of OA in mouse destabilization of the medial meniscus (DMM) model; it may also suppress apoptosis and senescence and promote the nuclear localization of TFEB in chondrocytes in vivo. This work suggests that 20-Deoxyingenol may alleviate osteoarthritis by activating TFEB in chondrocytes, while 20-DOI may become a potential drug for OA therapy.
To elucidate the role of LRRK2 in intervertebral disc degeneration (IDD) as well as its mitophagy regulation mechanism.
The expression of LRRK2 in human degenerative nucleus pulposus tissues as well ...as in oxidative stress-induced rat nucleus pulposus cells (NPCs) was detected by western blot. LRRK2 was knocked down in NPCs by lentivirus (LV)-shLRRK2 transfection; apoptosis and mitophagy were assessed by western blot, TUNEL assay, immunofluorescence staining and mitophagy detection assay in LRRK2-deficient NPCs under oxidative stress. After knockdown of Parkin in NPCs with siRNA transfection, apoptosis and mitophagy were further assessed. In puncture-induced rat IDD model, X-ray, MRI, hematoxylin-eosin (HE) and Safranin O-Fast green (SO) staining were performed to evaluate the therapeutic effects of LV-shLRRK2 on IDD.
We found that the expression of LRRK2 was increased in degenerative NPCs both in vivo and in vitro. LRRK2 deficiency significantly suppressed oxidative stress-induced mitochondria-dependent apoptosis in NPCs; meanwhile, mitophagy was promoted. However, these effects were abolished by the mitophagy inhibitor, suggesting the effect of LRRK2 on apoptosis in NPCs is mitophagy-dependent. Furthermore, Parkin knockdown study showed that LRRK2 deficiency activated mitophagy by recruiting Parkin. In vivo study demonstrated that LRRK2 inhibition ameliorated IDD in rats.
The results revealed that LRRK2 is involved in the pathogenesis of IDD, while knockdown of LRRK2 inhibits oxidative stress-induced apoptosis through mitophagy. Thus, inhibition of LRRK2 may be a promising therapeutic strategy for IDD.
Objectives
Diabetes is a risk factor for intervertebral disc degeneration (IVDD). Studies have demonstrated that diabetes may affect IVDD through transcriptional regulation; however, whether ...post‐transcriptional regulation is involved in diabetic IVDD (DB‐IVDD) is still unknown. This study was performed to illustrate the role of HuR, an RNA‐binding protein, in DB‐IVDD development and its mechanism.
Materials and Methods
The expression of HuR was evaluated in nucleus pulposus (NP) tissues from diabetic IVDD patients and in high glucose‐treated NP cells. Senescence and autophagy were assessed in HuR over‐expressing and downregulation NP cells. The mRNAs that were regulated by HuR were screened, and immunoprecipitation was applied to confirm the regulation of HuR on targeted mRNAs.
Results
The results showed that the expression of HuR was decreased in diabetic NP tissues and high glucose‐treated NP cells. Downregulation of HuR may lead to increased senescence in high glucose‐treated NP cells, while autophagy activation attenuates senescence in HuR deficient NP cells. Mechanistic study showed that HuR prompted Atg7 mRNA stability via binding to the AU‐rich elements. Furthermore, overexpression of Atg7, but not HuR, may ameliorate DB‐IVDD in rats in vivo.
Conclusions
In conclusion, HuR may suppress senescence through autophagy activation via stabilizing Atg7 in diabetic NP cells; while Atg7, but not HuR, may serve as a potential therapeutic target for DB‐IVDD.
With high‐glucose treatment, the expression of HuR is decreased, which induces autophagy inactivation and increased senescence. Mechanistic study reveals that HuR regulates Atg7 expression through binding to Atg7 AU‐rich element and adjusting its mRNA stability
Osteoarthritis (OA), a degenerative disorder, is considered to be one of the most common forms of arthritis. Limonin (Lim) is extracted from lemons and other citrus fruits. Limonin has been reported ...to have anti-inflammatory effects, while inflammation is a major cause of OA; thus, we propose that limonin may have a therapeutic effect on OA. In this study, the therapeutic effect of limonin on OA was assessed in chondrocytes in vitro in IL-1β induced OA and in the destabilization of the medial meniscus (DMM) mice in vivo. The Nrf2/HO-1/NF-κB signaling pathway was evaluated to illustrate the working mechanism of limonin on OA in chondrocytes. In this study, it was found that limonin can reduce the level of IL-1β induced proinflammatory cytokines such as INOS, COX-2, PGE2, NO, TNF-α, and IL-6. Limonin can also diminish the biosynthesis of IL-1β-stimulated chondrogenic catabolic enzymes such as MMP13 and ADAMTS5 in chondrocytes. The research on the mechanism study demonstrated that limonin exerts its protective effect on OA through the Nrf2/HO-1/NF-κB signaling pathway. Taken together, the present study shows that limonin may activate the Nrf2/HO-1/NF-κB pathway to alleviate OA, making it a candidate therapeutic agent for OA.
In this study, we used murine chondrocytes as an
model and mice exhibiting destabilization of the medial meniscus (DMM) as an
model to investigate the mechanisms through which S-allyl cysteine (SAC) ...alleviates osteoarthritis (OA). SAC significantly reduced apoptosis and senescence and maintained homeostasis of extracellular matrix (ECM) metabolism in tert-butyl hydroperoxide (TBHP)-treated chondrocytes. Molecular docking analysis showed a -CDOCKER interaction energy value of 203.76 kcal/mol for interactions between SAC and nuclear factor erythroid 2-related factor 2 (Nrf2). SAC increased the nuclear translocation of Nrf2 and activated the Nrf2/HO1 signaling pathway in TBHP-treated chondrocytes. Furthermore, Nrf2 knockdown abrogated the antiapoptotic, antisenescence, and ECM regulatory effects of SAC in TBHP-treated chondrocytes. SAC treatment also significantly reduced cartilage ossification and erosion, joint-space narrowing, synovial thickening and hypercellularity in DMM model mice. Collectively, these findings show that SAC ameliorates OA pathology in TBHP-treated chondrocytes and DMM model mice by activating the Nrf2/HO1 signaling pathway.
Silibinin is the major active constituent of the natural compound silymarin; several studies suggest that silibinin possesses antihepatotoxic properties and anticancer effects against carcinoma ...cells. However, no study has yet investigated the effect of silibinin on osteogenic differentiation of human bone marrow stem cells (hBMSCs). The aim of this study was to evaluate the effect of silibinin on osteogenic differentiation of hBMSCs. In this study, the hBMSCs were cultured in an osteogenic medium with 0, 1, 10 or 20μmol/l silibinin respectively. hBMSCs viability was analyzed by cell number quantification assay and cells osteogenic differentiation was evaluated by alkaline phosphatas (ALP) activity assay, Von Kossa staining and real time-polymerase chain reaction (RT-PCR). We found that silibinin promoted ALP activity in hBMSCs without affecting their proliferation. The mineralization of hBMSCs was enhanced by treatment with silibinin. Silibinin also increased the mRNA expressions of Collagen type I (COL-I), ALP, Osteocalcin (OCN), Osterix, bone morphogenetic protein-2 (BMP-2) and Runt-related transcription factor 2 (RUNX2). The BMP antagonist noggin and its receptor kinase inhibitors dorsomorphin and LDN-193189 attenuated silibinin-promoted ALP activity. Furthermore, BMP-responsive and Runx2-responsive reporters were activated by silibinin treatment. These results indicate that silibinin enhances osteoblast differentiation probably by inducing the expressions of BMPs and activating BMP and RUNX2 pathways. Thus, silibinin may play an important therapeutic role in osteoporosis patients by improving osteogenic differentiation of BMSCs.
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