Mouse Model Of Osteoarthritis Research Articles

Efficacy of serum-free cultured human umbilical cord mesenchymal stem cells in the treatment of knee osteoarthritis in mice.

We investigated the efficacy of intra-articular injection of human umbilical cord mesenchymal stem cells (hUC-MSCs) for the treatment of osteoarthritis (OA) progression in the knee joint. Although many experimental studies of hUC-MSCs have been published, these studies have mainly used fetal bovine serum-containing cultures of hUC-MSCs; serum-free cultures generally avoid the shortcomings of serum-containing cultures and are not subject to ethical limitations, have a wide range of prospects for clinical application, and provide a basis or animal experimentation for clinical experiments. To study the therapeutic effects of serum-free hUC-MSCs (N-hUCMSCs) in a mouse model of knee OA. Fifty-five male C57BL/6 mice were randomly divided into six groups: The blank control group, model control group, serum-containing hUC-MSCs (S-hUCMSC) group, N-hUCMSC group and hyaluronic acid (HA) group. After 9 weeks of modeling, the serum levels of interleukin (IL)-1β and IL-1 were determined. Hematoxylin-eosin staining was used to observe the cartilage tissue, and the Mankin score was determined. Immunohistochemistry and western blotting were used to determine the expression of collagen type II, matrix metalloproteinase (MMP)-1 and MMP-13. The Mankin score and serum IL-1 and IL-1β and cartilage tissue MMP-1 and MMP-13 expression were significantly greater in the experimental group than in the blank control group (P < 0.05). Collagen II expression in the experimental group was significantly lower than that in the blank control group (P < 0.05). The Mankin score and serum IL-1 and IL-1β and cartilage tissue MMP-1 and MMP-13 levels the experimental group were lower than those in the model control group (P < 0.05). Collagen II expression in the experimental group was significantly greater than that in the model control group (P < 0.05). N-hUCMSC treatment significantly alleviate the pathological damage caused by OA. The treatment effects of the S- hUCMSC group and HA group were similar.

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

BackgroundDiscovering an inhibitor for acyl-CoA synthetase long-chain family member 4 (ACSL4), a protein that triggers cell injury via ferroptosis, presents potential to minimize cellular damage. This study investigates paeonol (PAE), a traditional Chinese herbal medicine, as an ACSL4 inhibitor to prevent chondrocyte ferroptosis and protect against osteoarthritis (OA). MethodsWe conducted in vitro experiments using mouse chondrocytes treated with PAE to mitigate ferroptosis induced by Interleukin-1 Beta (IL-1β) or ferric ammonium citrate (FAC), examining intracellular ferroptotic indicators, cartilage catabolic markers, and ferroptosis regulatory proteins. A mouse OA model was created via destabilized medial meniscus (DMM), followed by intra-articular PAE injections. After 8 weeks, micro-computed tomography and histological assessments evaluated PAE's protective and anti-ferroptotic effects in the OA model. ResultsIn vitro results showed PAE significantly reduced IL-1β/FAC-induced damage by targeting ACSL4, including cell apoptosis, inflammatory responses, extracellular matrix degradation, and ferroptotic markers (oxidative stress, lipid peroxidation, and iron buildup). It also restored the expression of ferroptotic suppressors and mitigated mitochondrial damage. Additionally, PAE increased cartilage anabolic marker expression while reducing cartilage catabolic marker expression. Molecular docking, cellular thermal shift assay, and drug affinity responsive target stability analysis verified the binding interaction between PAE and ACSL4. Furthermore, the role of PAE in chondrocytes was further verified through ACSL4 knockdown and overexpression. In vivo, mice with OA showed increased cartilage degradation and ferroptosis, while intra-articular PAE injection alleviated these pathological changes. ConclusionPAE significantly protects chondrocytes from ferroptosis induced by IL-1β/FAC in primary mouse chondrocytes and DMM surgery-induced OA mice through ACSL4 inhibition. The translational potential of this articleThese findings highlight the potential of targeting ACSL4 in chondrocytes as a treatment strategy for OA, positioning PAE as a promising drug candidate.

Inhibition of PA28γ expression can alleviate osteoarthritis by inhibiting endoplasmic reticulum stress and promoting STAT3 phosphorylation.

Osteoarthritis (OA) is a common degenerative disease. PA28γ is a member of the 11S proteasome activator and is involved in the regulation of several important cellular processes, including cell proliferation, apoptosis, and inflammation. This study aimed to explore the role of PA28γ in the occurrence and development of OA and its potential mechanism. A total of 120 newborn male mice were employed for the isolation and culture of primary chondrocytes. OA-related indicators such as anabolism, catabolism, inflammation, and apoptosis were detected. Effects and related mechanisms of PA28γ in chondrocyte endoplasmic reticulum (ER) stress were studied using western blotting, real-time polymerase chain reaction (PCR), and immunofluorescence. The OA mouse model was established by destabilized medial meniscus (DMM) surgery, and adenovirus was injected into the knee cavity of 15 12-week-old male mice to reduce the expression of PA28γ. The degree of cartilage destruction was evaluated by haematoxylin and eosin (HE) staining, safranin O/fast green staining, toluidine blue staining, and immunohistochemistry. We found that PA28γ knockdown in chondrocytes can effectively improve anabolism and catabolism and inhibit inflammation, apoptosis, and ER stress. Moreover, PA28γ knockdown affected the phosphorylation of IRE1α and the expression of TRAF2, thereby affecting the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signalling pathways, and finally affecting the inflammatory response of chondrocytes. In addition, we found that PA28γ knockdown can promote the phosphorylation of signal transducer and activator of transcription 3 (STAT3), thereby inhibiting ER stress in chondrocytes. The use of Stattic (an inhibitor of STAT3 phosphorylation) enhanced ER stress. In vivo, we found that PA28γ knockdown effectively reduced cartilage destruction in a mouse model of OA induced by the DMM surgery. PA28γ knockdown in chondrocytes can inhibit anabolic and catabolic dysregulation, inflammatory response, and apoptosis in OA. Moreover, PA28γ knockdown in chondrocytes can inhibit ER stress by promoting STAT3 phosphorylation.

α-klotho reduces susceptibility to osteoarthritis: evidence from cross-sectional studies and Mendelian randomization.

Despite extensive research, the association between serum α-klotho levels and osteoarthritis (OA) remains unclear, predominantly relying on findings from OA mouse models. This study used data from the National Health and Nutrition Examination Survey (NHANES) to conduct a cross-sectional study examining the relationship between α-klotho and human OA. In addition, we used Mendelian randomization (MR) to genetically infer a causal relationship between serum α-klotho and the three OA subtypes. A cohort of 12,037 subjects from NHANES (2007-2016) was analyzed. Multivariate logistic regression was utilized to examine the association between α-klotho concentration and OA, alongside subgroup analysis and interaction tests. Additionally, a two-sample bi-directional MR analysis was conducted to evaluate the relationship between serum α-klotho and three OA subtypes, including all OA, hip OA, and knee OA, employing the inverse variance weighting (IVW) method as the primary approach. Following adjustment for covariates, a nonlinear negative correlation between serum α-klotho and OA was observed (OR=0.77; 95% CI, 0.68-0.88, p < 0.0001). The IVW method revealed that higher serum α-klotho levels were associated with decreased susceptibility to hip OA (OR = 0.92, 95% CI: 0.87-0.98, P = 9.64×10-3). However, MR analysis did not establish a causal relationship between serum α-klotho and OA or knee OA. Inverse MR also indicated that the three subtypes of OA do not causally affect serum α-klotho concentrations. In cross-sectional studies, α-klotho showed a nonlinear negative correlation with OA. MR analysis of outcomes was not identical to cross-sectional studies.

Ultra-Long-Term Anti-Inflammatory Polyphenol Capsule to Remodel the Microenvironment for Accelerating Osteoarthritis Healing by Single Dosage.

Osteoarthritis (OA) is a common chronic inflammatory disease that leads to disability and death. Existing therapeutic agents often require frequent use, which can lead to drug resistance and long-term side effects. Polyphenols have anti-inflammatory and antioxidant potential. However, they are limited by their short half-life and low bioavailability. This work presents a novel pure polyphenol capsule for sustained release of polyphenols, which is self-assembled via hydrophobic and hydrogen bonds. The capsule enhances cellular uptake, scavenges reactive oxygen and nitrogen species, reduces inflammatory markers, and remodels the OA microenvironment by inhibiting the p38 MAPK pathway. The capsule overcomes the limitations of short half-life and low bioavailability of polyphenols and achieves single-dose cure in mouse and dog OA models, providing an optimal therapeutic window for OA repair. Taking advantage of simple manufacturing, convenient administration, and pure polyphenol composition, these capsules show great potential for clinical treatment of osteoarthritis and chronic inflammatory diseases.

Histopathological characterization of mandibular condyles in four temporomandibular joint osteoarthritis mouse models

ObjectiveTemporomandibular joint osteoarthritis (TMJOA) has been modeled in different ways with a lack of uniformity. We aimed to investigate four TMJOA mouse models and assess histopathological changes in condyles, which could assist in the selection of animal models in further TMJOA-related studies. DesignFour TMJOA mouse models were established, including unilateral hyperocclusion, discectomy, monosodium iodoacetate injection and aged model. Bilateral condyles were collected at different time points. The condylar alterations were analyzed by Micro-CT, Hematoxylin and eosin staining, Toluidine blue staining, Safranin O staining, Trap staining, immunofluorescence staining, immunohistochemistry staining and quantitative polymerase chain reaction. ResultsRadiographic and histopathological analysis indicated that all four methods could cause condylar degeneration successfully. Differences in morphologic and histologic changes were found among four models. The hyperocclusion model was time-dependent and the lesions got worse over time. Discectomy model presented obvious damage of cartilage and subchondral bone. Injected model showed severe inflammation and chondrocyte hypertrophy. The aged model was characterized by decreased of proteoglycan and osteolysis. ConclusionsThe four methods had different characteristics and applicability. The harvest time affected the degree of cartilage degradation. Hyperocclusion was suited to explore the early-stage of TMJOA. Discectomy present advantages in investigating the long-term restoration of cartilage and subchondral bone. Monosodium iodoacetate-injection was appropriate for screening the agents for inflammatory relief. The aged model more naturally facilitated discovering underlying mechanisms in primary TMJOA. Unilateral modeling methods could initiate contralateral condylar alterations. The TMJOA models should be selected based on experimental requirements and applicability of each model.

RIP1 inhibition reduces chondrocyte apoptosis through downregulating nuclear factor-kappa B signaling in a mouse osteoarthritis model.

Excessive chondrocyte death is a critical player in the process of osteoarthritis (OA). The present study was aimed to study the role of receptor-interacting serine/threonine kinase (RIP) 1-mediated signaling for programmed cell death in OA. In the present study, RIP1 protein expression was evaluated in mouse OA cartilage and cultured primary murine chondrocytes exposed to tumor necrosis factor-alpha (TNF-α). Protein expression involved in necroptosis and apoptosis and chondrocyte-derived extracellular matrix were examined. Inhibition of RIP1 was conducted using the RNAi technique and pharmacological inhibition. Western blot, immunohistochemistry, and immunofluorescence examination were applied. The protein presence of RIP1, but not RIP3, was increased in the mouse OA tissue and cultured chondrocytes exposed to TNF-α. Knockdown of RIP1 increased protein expression of collagen II and sex-determining region Y-box transcription factor 9, and reduced protein expression of matrix metallopeptidases 13 and a disintegrin and metalloproteinase with thrombospondin motifs 5. Inhibition of RIP1 reduced the phosphorylated NF-κB signals, decreased cell apoptosis, and restored extracellular matrix expression in cultured chondrocytes. Both RNAi and pharmacological inhibition of RIP1 decelerated the progress of OA in mice. RIP1 regulates chondrocyte apoptosis through NF-κB signaling. Inhibition of RIP1 provides a novel therapeutic approach for OA therapy.

Astaxanthin mediated repair of tBHP-Induced cellular injury in chondrocytes

ABSTRACT Objective This study investigates how astaxanthin (AST) counters tert-butyl hydroperoxide (tBHP)-induced cellular damage in C28/I2 chondrocytes, focusing on the circ-HP1BP3/miR-139-5p/SOD1 signaling pathway and its use in sustained-release microspheres for osteoarthritis treatment. Methods We employed a variety of techniques including real-time quantitative PCR, Western blot, ELISA, and dual-luciferase reporter gene assays to explore AST's molecular effects. Additionally, the efficacy of AST-loaded sustained-release microspheres was evaluated in vitro and in a mouse model of osteoarthritis. Results AST significantly enhanced SOD1 expression, reducing apoptosis and inflammation in damaged cells. The AST-loaded microspheres showed promising in vitro drug release, improved cell viability, and reduced oxidative stress. In the osteoarthritis mouse model, they effectively decreased joint inflammation and increased the expression of chondrocyte markers. Conclusion Astaxanthin effectively mitigates oxidative stress and inflammation in chondrocytes via the circ-HP1BP3/miR-139-5p/SOD1 pathway. The development of AST-loaded microspheres offers a novel and promising approach for osteoarthritis therapy, potentially extending to osteoarthritis treatment.

CRISPR/CasRx-mediated RNA knockdown targeting β-catenin and Ihh signaling alleviates osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disease. Currently, OA is incurable. Abnormal activation of canonical Wnt/β-catenin or Indian hedgehog (Ihh) signaling could lead to OA development and progression. This study aimed to determine if targeting β-catenin and Ihh signaling could yield an effective therapeutic intervention for OA disease. CRISPR/CasRx is a new RNA interference tool that can precisely and efficiently cleave single-strand RNAs. In this study, we screened CRISPR-derived RNA (crRNA) targeting Ctnnb1 and Smo in vitro and selected two optimal crRNAs for each gene. CasRx-mediated Ctnnb1 and Smo knockdown showed high efficiency and specificity with no obvious off-target effects in vitro. We then performed intra-articular injection of selected crRNAs driven by the adeno-associated virus into an OA mouse model. Micro-CT, histological, and histomorphometric analyses were conducted to evaluate the efficacy of CasRx approach on OA treatment. We found that the knockdown of Ctnnb1 and Smo decelerated pathological damage in the keen joint of the experimental OA mouse model. Our findings suggest that CasRx-mediated Ctnnb1 and Smo knockdown could be a potential strategy for OA treatment.

Increased Rab1a accelerates osteoarthritis by inhibiting autophagy via activation of the mTORC1-S6K pathway

IntroductionCartilage degradation is a critical alteration in the progression of osteoarthritis (OA) due to the disorder of chondrocyte metabolic homeostasis. Autophagy plays an important role in maintaining intracellular homeostasis. Recent investigations have increasingly underscored the importance of autophagy in modulating the pathological mechanisms underlying OA. Ras-related protein Rab-1a (Rab1a) has been illustrated to regulate autophagy in many diseases but not in OA. ObjectivesThis study aims to elucidate whether Rab1a could regulate the development of OA through modulation of chondrocyte autophagy and apoptosis. MethodsProteomic sequencing, Western blotting, and immunohistochemistry were applied to detect the expression level of Rab1a in vitro and in vivo. Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were rigorously identified. The effects of Rab1a and the interaction between Rab1a, mTORC1, autophagy and apoptosis were explored by qPCR, Western blotting, and immunofluorescence. An experimental mouse OA model was also performed to confirm the role of Rab1a in OA pathogenesis in vivo. Histological analysis was employed to demonstrate cartilage damage. ResultsRab1a expression was significantly upregulated in inflamed chondrocytes and knee OA cartilage. Inhibition of Rab1a partially attenuated the degradation of the extracellular matrix and cell apoptosis both in vitro and in vivo, whereas overexpression of Rab1a intensified cartilage matrix degradation and cellular apoptosis. Additionally, elevated Rab1a levels were observed to suppress autophagy and activate the mTORC1-S6K signaling pathway, thereby aggravating OA pathogenesis. ConclusionThe augmentation of Rab1a expression impairs autophagy and promotes apoptosis through the activation of the mTORC1-S6K signaling pathway, further exacerbating OA pathogenesis. This finding suggests that Rab1a serves as a promising and innovative therapeutic target for the prevention and treatment of OA.

Loganin inhibits the ROS-NLRP3-IL-1β axis by activating the NRF2/HO-1 pathway against osteoarthritis

Loganin (LOG), a bioactive compound derived from Cornus officinalis Siebold & Zucc, has been understudied in the context of osteoarthritis (OA) treatment. In this study, we induced an inflammatory response in chondrocytes using lipopolysaccharide (LPS) and subsequently treated these cells with LOG. We employed fluorescence analysis to quantify reactive oxygen species (ROS) levels and measured the expression of NLRP3 and nuclear factor erythropoietin-2-related factor 2 (NRF2) using real-time quantitative polymerase chain reaction (qRT-PCR), Western blotting, and immunofluorescence (IF) techniques. Additionally, we developed an OA mouse model by performing medial meniscus destabilization (DMM) surgery and monitored disease progression through micro-computed tomography (micro-CT), hematoxylin and eosin (H&E) staining, safranin O and fast green (S&F) staining, and immunohistochemical (IHC) analysis. Our results indicate that LOG significantly reduced LPS-induced ROS levels in chondrocytes, inhibited the activation of the NLRP3 inflammasome, and enhanced NRF2/heme oxygenase 1 (HO-1) signaling. In vivo, LOG treatment mitigated cartilage degradation and osteophyte formation triggered by DMM surgery, decreased NLRP3 expression, and increased NRF2 expression. These findings suggest that LOG has a protective effect against OA, potentially delaying disease progression by inhibiting the ROS-NLRP3-IL-1β axis and activating the NRF2/HO-1 pathway.

Comparison of post-traumatic osteoarthritis mouse models

Comparison of post-traumatic osteoarthritis mouse models

IGF1 drives Wnt-induced joint damage and is a potential therapeutic target for osteoarthritis

Osteoarthritis is the most common joint disease and a global leading cause of pain and disability. Current treatment is limited to symptom relief, yet there is no disease-modifying therapy. Its multifactorial etiology includes excessive activation of Wnt signaling, but how Wnt causes joint destruction remains poorly understood. Here, we identify that Wnt signaling promotes the transcription of insulin-like growth factor 1 (IGF1) in articular chondrocytes and that IGF1 is a major driver of Wnt-induced joint damage. Male mice with cartilage-specific Igf1 deficiency are protected from Wnt-triggered joint disease. Mechanistically, Wnt-induced IGF1 transcription depends on β-catenin and binding of Wnt transcription factor TCF4 to the IGF1 gene promoter. In a clinically relevant mouse model of post-traumatic osteoarthritis, cartilage-specific deletion of Igf1 protects against the disease in male mice. IGF1 silencing in chondrocytes from patients with osteoarthritis restores a healthy molecular profile. Our findings reveal that reducing Wnt-induced IGF1 is a potential therapeutic strategy for osteoarthritis.

Molybdenum nanodots act as antioxidants for photothermal therapy osteoarthritis

Osteoarthritis (OA) manifests as the degradation of cartilage and remodeling of subchondral bone. Restoring homeostasis within the joint is imperative for alleviating OA symptoms. Current interventions primarily target singular aspects, such as anti-aging, inflammation inhibition, free radical scavenging, and regeneration of cartilage and subchondral bone. Herein, we developed molybdenum nanodots (MNDs) as bionic photothermal nanomaterials to mimic the antioxidant synthase to concurrently protected cartilage and facilitate subchondral bone regeneration. With near-infrared (NIR) irradiation, MNDs effectively eliminate reactive oxygen and nitrogen species (ROS/RNS) from OA chondrocytes, thereby reversed mitochondrial dysfunction, mitigating chondrocyte senescence, and simultaneously suppresses inflammation, hence preserving the inherent homeostasis between cartilage matrix synthesis and degradation while circumventing safety concerns. RNA sequencing of OA chondrocytes treated with MNDs-NIR revealed the reinstatement of chondrocyte functionality, activation of antioxidant enzymes, anti-aging properties, and regulation of inflammation. NIR irradiation induces thermogenesis and synergistically promotes subchondral bone regeneration via MNDs, as validated through histological assessments and microcomputed tomography (Micro-CT) scans. MNDs-NIR effectively attenuate cellular senescence and inhibit inflammation in vivo, while also remodeling mitochondrial dynamics by upregulating fusion proteins and inhibiting fission proteins, thereby regulating the oxidative stress microenvironment. Additionally, MNDs-NIR exhibited remarkable therapeutic effects in alleviating articular cartilage degeneration in an OA mouse model, evidenced by a 1.67-fold reduction in subchondral bone plate thickness, an 88.57 % decrease in OARSI score, a 5.52-fold reduction in MMP13 expression, and a 6.80-fold increase in Col II expression. This novel disease-modifying approach for OA utilizing MNDs-NIR offers insight and a paradigm for improving mitochondrial dysfunction by regulating the accumulation of mitochondrial ROS and ultimately alleviating cellular senescence. Moreover, the dual-pronged therapeutic approach of MNDs-NIR, which addresses both cartilage erosion and subchondral bone lesions in OA, represents a highly promising strategy for managing OA.

Targeting Synovial Macrophages with Astaxanthin-Loaded Liposomes for Antioxidant Treatment of Osteoarthritis.

Osteoarthritis (OA) is a chronic joint disease highly associated with an imbalance in the network of inflammatory factors and typically characterized by oxidative stress and cartilage damage. Moreover, the specificity of the joint structure makes it difficult for drugs to achieve good penetration and effective enrichment in the joint cavity. Therefore, therapeutic strategies that increase the specific targeting of drugs to inflammatory joint and incorporate antioxidative stress effects are important to improve the efficacy of OA. Here, we developed a folic acid-modified liposomal nanoparticle (AST@Lip-FA) loaded with the antioxidant astaxanthin (AST) to enhance the water solubility and stability of AST and to target the delivery of AST to the site of OA, leading to a significant improvement in therapeutic efficacy. In vitro experiments demonstrated that, due to the recognition by FA of the receptor folate receptor β on the surface of activated macrophages, the cellular uptake efficiency of AST@Lip-FA was increased. Meanwhile, intracellularly overexpressed inflammatory mediators such as reactive oxygen species and nitric oxide were efficiently removed by AST@Lip-FA. In addition, in the ACLT-induced OA mouse model, AST@Lip-FA was precisely enriched in the inflamed joints and achieved long-term retention, fully utilizing the anti-inflammatory, antioxidant, and cartilage-protecting effects of AST to effectively alleviate the progression of OA. In summary, AST@Lip-FA has an important prospect as a potential and effective therapeutic strategy for OA.

New role of calcium-binding fluorescent dye alizarin complexone in detecting permeability from articular cartilage to subchondral bone.

Osteoarthritis (OA) is a chronic degenerative joint disorder characterized by the progressive deterioration of articular cartilage and concomitant alterations in subchondral bone architecture. However, the precise mechanisms underlying the initiation and progression of OA remains poorly understood. In the present study, we explored whether the calcification in the articular cartilage occurred in the early stage of mouse OA model, generated by the surgery destabilization of the medial meniscus (DMM), via the intra-articular injection of alizarin complexone due to its anionic nature for binding calcium-containing crystals. Although we did not observe the calcification in the articular cartilage of early stage of DMM mice, we unexpectedly identified alizarin complexone had the diffusion capacity for detecting the permeability from the articular cartilage to subchondral bone. Our data showed that the diffusion of alizarin complexone from the articular cartilage to calcified cartilage was greater in the early stage of DMM mice than that in sham controls. Additionally, we observed enhanced penetration of alizarin complexone through the periosteum in DMM mice compared to sham mice. In summary, we developed a novel imaging method that offers a valuable tool for further exploration of biochemical communication underlying OA development. Our findings provided new evidence that increased molecular interactions between the articular cartilage and subchondral bone is involved in the pathogenesis of OA progression.

Targeted Therapy of Osteoarthritis via Intra-Articular Delivery of Lipid-Nanoparticle-Encapsulated Recombinant Human FGF18 mRNA.

Fibroblast growth factor 18 (FGF18) emerges as a promising therapeutic target for osteoarthritis (OA). In this study, a novel articular cavity-localized lipid nanoparticle (LNP) named WG-PL14 is developed. This optimized formulation has a nearly 30-fold increase in mRNA expression as well as better articular cavity enrichment compared to commercial lipids MC3 when performing intra-articular injection. Then, a mRNA sequence encoding recombinant human FGF18 (rhFGF18) for potential mRNA therapy in OA is optimized. In vitro assays confirm the translation of rhFGF18 mRNA into functional proteins within rat and human chondrocytes, promoting cell proliferation and extracellular matrix (ECM) synthesis. Subsequently, the therapeutic efficacy of the LNP-rhFGF18 mRNA complex is systematically assessed in a mouse OA model. The administration exhibits several positive outcomes, including an improved pain response, upregulation of ECM-related genes (e.g., AGRN and HAS2), and remodeling of subchondral bone homeostasis compared to a control group. Taken together, these findings underscore the potential of localized LNP-rhFGF18 mRNA therapy in promoting the regeneration of cartilage tissue and mitigating the progression of OA.

Forsythoside A mitigates osteoarthritis and inhibits chondrocyte senescence by promoting mitophagy and suppressing NLRP3 inflammasome via the Nrf2 pathway

BackgroundChondrocyte senescence and inflammation are hallmarks of osteoarthritis (OA). Forsythiaside A (FTA), a phenylethanol glycoside isolated from air-dried fruits of Forsythia, has been reported to have significant anti-inflammatory and antioxidant properties. However, its protective effects against OA have not been elucidated. PurposeWe explored the therapeutic efficacy of FTA in inhibiting chondrocyte senescence and inflammation during OA, as well as the potential underlying mechanisms. Study designThis study aimed to investigate the novel mechanism of FTA in alleviating OA in both cell and animal models. MethodsThe protective effect of FTA against tert-butyl hydroperoxide-induced chondrocyte damage was assessed, and the effects of FTA on cartilage aging and OA progression were evaluated using a medial meniscus (DMM)-induced knee OA mouse model. The regulatory effects of FTA on the NLRP3 Inflammasome, mitophagy, and the PKC/Nrf2 pathway were also explored. ResultsIn vitro, FTA improved mitochondrial function, enhanced mitophagy, suppressed NLRP3 inflammasome activation, and inhibited chondrocyte senescence; however, these chondroprotective effects were partially reversed after mitophagy inhibition, NLRP3 inflammasome activation, and Nrf2 pathway inhibition. Furthermore, we found that FTA directly interacts with Nrf2 and enhances its phosphorylation by protein kinase C (PKC). In vivo, FTA attenuated the pathological signs of knee OA in a DMM-model mouse model, which was partially reversed by ML385. ConclusionFTA inhibited chondrocyte senescence and OA progression by activating the PKC–Nrf2 pathway. Thus, FTA is a potential novel therapeutic agent for OA.

Natural synergy: Oleanolic acid-curcumin co-assembled nanoparticles combat osteoarthritis

Curcumin (Cur) is a natural polyphenol that is one of the most valuable natural products. However, its use as a functional food is limited by low water solubility, chemical instability and poor bioavailability. In this study, a supramolecular co-assembly strategy was used to construct an oleanolic acid-curcumin (OLA-Cur) co-assembly composite nano-slow-release treatment system. As a co-assembled compound, OLA is a widely present pentacyclic triterpenoid compound with multiple biological activities in the plant kingdom, which is expected to jointly alleviate the damaging effects of papain-induced mouse osteoarthritis model. The OLA-Cur NPs shows the solid core-shell structure, which can effectively improve the water solubility of Cur and OLA, and has good stability and sustained release characteristics. The analysis results show that the two compounds are mainly assembled through hydrogen bonding interactions, hydrophobic interactions, and π - π stacking interactions. The OLA-Cur NPs can inhibit the release of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β induced by LPS in RAW264.7 mouse macrophages, promote the secretion of anti-inflammatory cytokine IL-10, and improve the oxidative stress index of hydrogen peroxide induced human rheumatoid arthritis synovial fibroblasts. In addition, it has a certain improvement effect on cartilage and subchondral bone damage in mouse osteoarthritis models. These findings suggest that constructing co-assembled composite nanoparticles based on pure natural compounds may break through the limitations of a variety of important nutritional ingredients in functional foods.

An intra articular injectable Mitocelle recovers dysfunctional mitochondria in cellular organelle disorders

Mitochondrial dysfunction increases ROS production and is closely related to many degenerative cellular organelle diseases. The NOX4-p22phox axis is a major contributor to ROS production and its dysregulation is expected to disrupt mitochondrial function. However, the field lacks a competitive inhibitor of the NOX4-p22phox interaction. Here, we created a povidone micelle-based Prussian blue nanozyme that we named “Mitocelle” to target the NOX4-p22phox axis, and characterized its impact on the major degenerative cellular organelle disease, osteoarthritis (OA). Mitocelle is composed of FDA-approved and biocompatible materials, has a regular spherical shape, and is approximately 88 nm in diameter. Mitocelle competitively inhibits the NOX4-p22phox interaction, and its uptake by chondrocytes can protect against mitochondrial malfunction. Upon intra-articular injection to an OA mouse model, Mitocelle shows long-term stability, effective uptake into the cartilage matrix, and the ability to attenuate joint degradation. Collectively, our findings suggest that Mitocelle, which functions as a competitive inhibitor of NOX4-p22phox, may be suitable for translational research as a therapeutic for OA and cellular organelle diseases related to dysfunctional mitochondria.