Osteoarthritis In Mice Research Articles

Comparison of post-traumatic osteoarthritis mouse models

Comparison of post-traumatic osteoarthritis mouse models

Differential effects of alendronate on chondrocytes, cartilage matrix and subchondral bone structure in surgically induced osteoarthritis in mice

Bisphosphonates (BP) are considered a treatment option for osteoarthritis (OA) due to reduction of OA-induced microtrauma in the bone marrow, stabilization of subchondral bone (SB) layer and pain reduction. The effects of high-dose alendronate (ALN) treatment on SB and articular cartilage after destabilization of the medial meniscus (DMM) or Sham surgery of male C57Bl/6J mice were analyzed. We performed serum analysis; histology and immunohistochemistry to assess the severity of OA and a possible pain symptomatology. Subsequently, the ratio of bone volume to total volume (BV/TV), epiphyseal trabecular morphology and the bone mineral density (BMD) was analyzed by nanoCT. Serum analysis revealed a reduction of ADAMTS5 level. The histological evaluation displayed no protective effect of ALN-treatment on cartilage erosion. NanoCT-analysis of the medial epiphysis revealed an increase of BV/TV in ALN-treated mice. Only the DMM group had significantly higher SB volume accompanied by decreased subchondral bone surface. Furthermore Nano-CT analysis revealed an increase in trabecular density and number, a decreased BMD and reduced osteophyte formation in the ALN mice. ALN treatment affected bone micro-architecture by reducing osteophytosis with simultaneous increasing subchondral bone plate thickness, trabecular thickness and BMD. Accordingly, ALN cannot be considered as a potential treatment strategy in general, however in a subgroup of patients with high bone turnover in an early-stage of OA, ALN might be an option when applied during a restricted time frame.

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.

Amentoflavone maintaining extracellular matrix homeostasis and inhibiting subchondral bone loss in osteoarthritis by inhibiting ERK, JNK and NF-κB signaling pathways

Amentoflavone (AF), a plant biflavone isolated from Selaginella sinensis ethanol extract, is characterized by anti-inflammatory and anti-oxidant properties. According to previous studies, inflammation and oxidative stress are closely related to the pathophysiology of osteoarthritis (OA). However, the effects and mechanisms of AF on OA have not been elucidated.To investigate the inhibitory effects and its molecular mechanism of AF on extracellular matrix (ECM) degradation stimulated by IL-1β as well as subchondral bone loss induced by RANKL in mice chondrocytes. Quantitative PCR was used to detect the mRNA expression of genes related to inflammation, ECM, and osteoclast differentiation. Protein expression level of iNOS, COX-2, MMP13, ADAMTS5, COL2A1, SOX9, NFATc1, c-fos, JNK, ERK, P65, IκBα was measured by western blotting. The levels of TNF-α and IL-6 in the supernatants were measured by ELISA. The amount of ECM in chondrocytes was measured using toluidine blue staining. The levels of Aggrecan and Col2a1 in chondrocytes were measured using immunofluorescence. Tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining and immunofluorescence were used to detect the effect of AF on osteoclast differentiation and bone resorption. The effect of AF on destabilization of the medial meniscus (DMM)-induced OA mice can be detected in hematoxylin–eosin (H&E) staining, Safranin O green staining and immunohistochemistry.AF might drastically attenuated IL-1β-stimulated inflammation and reduction of ECM formation by blocking ERK and NF-κB signaling pathways in chondrocytes. Meanwhile, AF suppressed the formation of osteoclasts and the resorption of bone function induced by RANKL. In vivo, AF played a protective role by stabilizing cartilage ECM and inhibiting subchondral bone loss in destabilization of the medial meniscus (DMM)-induced OA mice, further proving its protective effect in the development of OA. Our study show that AF alleviated OA by suppressing ERK, JNK and NF-κB signaling pathways in OA models in vitro and DMM-induced OA mice, suggesting that AF might be a potential therapeutic agent in the treatment of OA.

Extracellular vesicles from inflammatory-stimulated BMSCs ameliorate osteoarthritis via Rpl14 mediated synovial macrophage polarization

Bone marrow mesenchymal stem cells (BMSCs) and extracellular vesicles (EVs) were considered promising methods for the treatment of diverse diseases, including osteoarthritis (OA). However, the role of inflammatory-stimulated BMSCs driven EVs (iBMSC-EVs) in OA remains unclear. This study aims to investigate the potential function of iBMSC-EVs in ameliorating OA and its underlying molecular mechanism. In this study, EVs were isolated from inflammatory-stimulated BMSCs and destabilization of the medial meniscus (DMM) surgery was performed to induce knee OA model in mice. Micro-CT, H&E Staining, Safranin O-Fast Green Staining and immunofluorescence were used to examine the in vivo therapeutic effect of iBMSC-EVs on OA. Public single-cell RNA-seq data was downloaded and bulk RNA-seq data was acquired to identify critical genes promoted by iBMSC-EVs in macrophage polarization during OA. Real-time quantitative polymerase chain reaction (RT-qPCR), western blot, enzyme-linked immunosorbent assay (ELISA), cell counting kit-8 (CCK-8), transwell and scratch assays were used to further confirm the in vitro effect of iBMSC-EVs on macrophage polarization and chondrocyte proliferation, migration, as well as ECM anabolism and catabolism. In vivo experiments demonstrated that iBMSC-EVs could alleviate OA in mice and promote the reprogramming of M1 macrophages towards an M2 phenotype. RNA-Seq and scRNA-Seq analyses indicated that iBMSC-EVs altered the expression profiles of OA-related genes, with Rpl14 identified as a critical gene regulating macrophage reprogramming in OA. In vivo and in vitro experiments further confirmed that iBMSC-EVs, by downregulating Rpl14 expression, promoted M1 macrophage reprogramming to M2, facilitating chondrocyte proliferation and migration, inhibiting ECM degradation and ultimately alleviating OA progression. In conclusion, our data revealed the substantive role of iBMSC-EVs in ameliorating OA progression via Rpl14 mediated synovial macrophage polarization, presenting a promising therapeutic method for the treatment of OA.

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.

Knockdown of nuclear protein 1 delays pathological pro-gression of osteoarthritis through inhibiting chondrocyte ferroptosis.

To investigate the effect of nuclear protein 1 (Nupr1) on the pathological progression of osteoarthritis and its relationship with ferroptosis of chondrocytes. Chondrocytes of mouse knee were divided into small interfering RNA (siRNA) control group, small interfering RNA targeting Nupr1 (siNupr1) group, siRNA control+IL-1β group (siRNA control interference for 24 h followed by 10 ng/mL IL-1β) and siNupr1+IL-1β group (siNupr1 interference for 24 h followed by 10 ng/mL IL-1β). The protein and mRNA expressions of Nupr1 were detected by Western blotting and real-time RT-PCR. Cell proliferation viabilities were measured using the cell counting kit-8 method. The levels of ferrous ions were detected by FerroOrange staining. Lipid peroxidation levels were detected by C11-BODIPY-591 fluorescence imaging. The contents of malondialdehyde (MDA) and glutathione (GSH) were detected by enzyme-linked immunosorbent assay. The protein expressions of long-chain acyl-coenzyme A synthetase 4 (ACSL4), tumor protein 53 (P53), glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 gene (SLC7A11) were detected by Western blotting. The osteoarthritis model was constructed by destabilization of the medial meniscus (DMM) surgery in 7-week-old male C57BL/6J mice. The mice were randomly divided into 4 groups with 10 animals in each group: sham surgery (Sham)+adeno-associated virus serotype 5 (AAV5)-Short hairpin RNA (shRNA) control group, Sham+AAV5-shRNA targeting Nupr1 (shNupr1) group, DMM+AAV5-shRNA group, and DMM+AAV5-shNupr1 group. Hematoxylin and eosin staining and Safranin O-Fast Green staining were used to observe the morphological changes in cartilage tissue. The Osteoarthritis Research Society International (OARSI) osteoarthritis cartilage histopathology assessment system was used to evaluate the degree of cartilage degeneration in mice. The mRNA expressions of Nupr1, matrix metallopeptidase 13 (MMP13), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), cyclooxygenase 2 (COX2), and glutathione peroxidase 4 (GPX4) were detected by real-time RT-PCR. In vitro experiments showed that knocking down Nupr1 alleviated the decrease of chondrocyte proliferation activity induced by IL-1β, reduced iron accumulation in mouse chondrocytes, lowered the lipid peroxidation, downregulated ACLS4 and P53 protein expression and upregulated GPX4 and SLC7A11 protein expression (all P<0.01), thereby inhibiting ferroptosis in mouse chondrocytes. Meanwhile, in vivo animal experiments demonstrated that knocking down Nupr1 delayed the degeneration of articular cartilage in osteoarthritis mice, improved the OARSI score, slowed down the degradation of the extracellular matrix in osteoarthritis cartilage, and reduced the expression of the key ferroptosis regulator GPX4 (all P<0.01). Knockdown of Nupr1 can delay the pathological progression of osteoarthritis through inhibiting ferroptosis in mouse chondrocytes.

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.

Rosmarinic acid promotes cartilage regeneration through Sox9 induction via NF-κB pathway inhibition in mouse osteoarthritis progression

BackgroundThe natural polyphenolic compound known as Rosmarinic acid (RosA) can be found in various plants. Although its potential health benefits have been extensively studied, its effect on osteoarthritis (OA) progression and cartilage regeneration function still needs to be fully elucidated in OA animal models. This study elucidated the effect of RosA on OA progression and cartilage regeneration. MethodsIn vitro assessments were conducted using RT-PCR, qRT-PCR, Western blotting, and ELISA to measure the effects of RosA. The molecular mechanisms of RosA were determined by analyzing the translocation of p65 into the nucleus using immunocytochemistry (ICC). Histological analysis of cartilage explant was performed using alcian blue staining and immunohistochemistry (IHC). For in vivo analysis, the destabilization of the medial meniscus (DMM)-induced OA mouse model was utilized to evaluate cartilage destruction through Safranin-O staining. The expression of catabolic and anabolic factors in mice knee joints was quantified by immunohistochemistry. ResultsThe expression of catabolic factors in chondrocytes was significantly impeded by RosA. It also suppressed the NF-κB signaling pathway by decreasing phosphorylation of p65 and reducing degradation of IκB protein. In ex vivo experiments, RosA protected sulfated proteoglycan erosion triggered by IL-1β and suppressed the catabolic factors in cartilage explant. RosA treatment in animal models resulted in preventing cartilage destruction and reducing catabolic factors in the cartilage. RosA was also found to promote the expression of Sox9, Col2a1, and Acan in vitro, ex vivo, and in vivo analyses. ConclusionsRosA attenuated the OA progression by suppressing the catabolic factors expression. These effects were facilitated through the suppression of the NF-κB signaling pathway. Additionally, it promotes cartilage regeneration by inducing anabolic factors. Therefore, RosA shows potential as an effective therapeutic agent for treating 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.

Decreased histone H3K9 dimethylation in synergy with DNA demethylation of Spi-1 binding site contributes to ADAMTS-5 expression in articular cartilage of osteoarthritis mice.

Osteoarthritis (OA) is defined by articular cartilage degeneration, synovial membrane inflammation, and abnormal bone remodeling. Recent study has discovered that OA development is linked to an aberrant epigenetic modification of OA-related genes. Our previous research showed that DNA demethylation in ADAMTS-5 promoter region had a substantial impact on ADAMTS-5 expression in the mouse OA model. This process facilitated the binding of Spi-1 to ADAMTS-5 promoter. While alterations in histone methylation have been documented during embryonic development and cancer development, there is a paucity of data on the change in OA pathogenesis. Even no data have been reported on the role of histone modifications in ADAMTS-5 activation in OA. Following our previous study on the role of DNA methylation, we aimed to examine the contribution of histone H3K9 dimethylation in ADAMTS-5 activation in OA. Additionally, we aimed to elucidate the molecular mechanisms underlying the cooperative interaction between DNA methylation and histone H3K9 dimethylation. The potential for anti-OA intervention therapy which is based on modulating histone H3K9 dimethylation is also explored. We demonstrated that a reduction in histone H3K9 dimethylation, along with DNA demethylation of the Spi-1 binding site, had a role in ADAMTS-5 activation in the articular cartilage of OA mice. Significantly, the conditional deletion of histone demethylase to be identified as lysine-specific demethylase 1 (LSD1) in articular cartilage could alleviate the degenerative features of OA mice. Our study demonstrates the direct impact of histone H3K9 dimethylation on gene expression, which in turn contributes to OA development. This research enhances our understanding of the underlying causes of OA.

PU.1 regulates osteoarthritis progression via CSF1R in synovial cells

This study elucidates the molecular mechanisms driving osteoarthritis (OA) by focusing on the transcription factor PU.1's role in synovial cells, specifically macrophages and fibroblast-like synoviocytes (FLS). Analyzing OA-related synovial gene expression from the GEO database highlighted immune regulation pathways in OA. Using protein-protein interaction and the JASPAR database, we pinpointed essential genes in OA development. Synovial tissues from OA patients and controls revealed pronounced PU.1 and its target CSF1R presence. In a surgically induced OA mouse model with PU.1 and CSF1R knockdown, ChIP assays confirmed PU.1's binding to the CSF1R promoter. Dual luciferase reporter assays and immunohistochemistry validated PU.1's regulatory impact on CSF1R transcription. Combined analysis of microarrays GSE55235 and GSE206848 showed heightened PU.1 expression in OA, associated with immune regulation in macrophages. In vitro findings aligned with in vivo results, emphasizing PU.1's influence on macrophage polarization and FLS-induced inflammation. PU.1's direct activation of CSF1R transcription underpins its key role in OA progression. This research offers insights into OA's molecular basis, suggesting potential therapeutic targets.

Ginkgolide A enhances FoxO1 expression and reduces endoplasmic reticulum stress to mitigate osteoarthritis in mice

This study aimed to investigate the effects of Ginkgolide A (GA) on chondrocytes under oxidative stress and to elucidate its potential molecular mechanisms. Using a destabilization of the medial meniscus (DMM) model in mice and an in vitro osteoarthritis (OA) model induced by tert-butyl hydroperoxide (TBHP) in chondrocytes, we validated the therapeutic efficacy and underlying mechanisms of GA. Potential OA targets of GA were identified through network pharmacology, Gene Ontology (GO) analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Further exploration into the effects on endoplasmic reticulum stress (ERS), apoptosis, extracellular matrix (ECM) degradation, and Forkhead Box O1 (FoxO1) related pathways was conducted using Western blotting, immunofluorescence, TUNEL staining, flow cytometry, X-ray, micro-computed tomography (Micro-CT) analysis, and histological staining. The results demonstrated that GA upregulated FoxO1 expression and inhibited ERS-related signaling pathways, thereby reducing apoptosis and ECM degradation. In conclusion, GA significantly alleviated OA symptoms both in vitro and in vivo, suggesting its potential as a therapeutic agent for OA.

Novel multitarget analgesic candidate SZV-1287 demonstrates potential disease-modifying effects in the monoiodoacetate-induced osteoarthritis mouse model.

Monoiodoacetate (MIA)-induced osteoarthritis (OA) is the most commonly used rodent model for testing anti-OA drug candidates. Herein, we investigated the effects of our patented multitarget drug candidate SZV-1287 (3-(4,5-diphenyl-1,3-oxazol-2-yl) propanal oxime) that is currently under clinical development for neuropathic pain and characterized the mouse model through complex functional, in vivo imaging, and morphological techniques. Knee OA was induced by intraarticular MIA injection (0.5 and 0.8mg). Spontaneous pain was assessed based on weight distribution, referred pain by paw mechanonociception (esthesiometry), edema by caliper, neutrophil myeloperoxidase activity by luminescence, matrix metalloproteinase activity, vascular leakage and bone remodeling by fluorescence imaging, bone morphology by micro-CT, histopathological alterations by semiquantitative scoring, and glia activation by immunohistochemistry. Then, SZV-1287 (20mg/kg/day) or its vehicle was injected intraperitoneally over a 21-day period. MIA induced remarkably decreased thresholds of weight bearing and paw withdrawal, alterations in the tibial and femoral structures (reactive sclerosis, increased trabeculation, and cortical erosions), histopathological damage (disorganized cartilage structure, hypocellularity, decreased matrix staining and tidemark integrity, and increased synovial hyperplasia and osteophyte formation), and changes in the astrocyte and microglia density in the lumbar spinal cord. There were no major differences between the two MIA doses in most outcome measures. SZV-1287 inhibited MIA-induced weight bearing reduction, hyperalgesia, edema, myeloperoxidase activity, histopathological damage, and astrocyte and microglia density. SZV-1287 may have disease-modifying potential through analgesic, anti-inflammatory, and chondroprotective effects. The MIA mouse model is valuable for investigating OA-related mechanisms and testing compounds in mice at an optimal dose of 0.5mg.

Engineering exosomes derived from TNF-α preconditioned IPFP-MSCs enhance both yield and therapeutic efficacy for osteoarthritis

BackgroundThe pathogenesis of osteoarthritis (OA) involves the progressive degradation of articular cartilage. Exosomes derived from mesenchymal stem cells (MSC-EXOs) have been shown to mitigate joint pathological injury by attenuating cartilage destruction. Optimization the yield and therapeutic efficacy of exosomes derived from MSCs is crucial for promoting their clinical translation. The preconditioning of MSCs enhances the therapeutic potential of engineered exosomes, offering promising prospects for application by enabling controlled and quantifiable external stimulation. This study aims to address these issues by employing pro-inflammatory preconditioning of MSCs to enhance exosome production and augment their therapeutic efficacy for OA.MethodsThe exosomes were isolated from the supernatant of infrapatellar fat pad (IPFP)-MSCs preconditioned with a pro-inflammatory factor, TNF-α, and their production was subsequently quantified. The exosome secretion-related pathways in IPFP-MSCs were evaluated through high-throughput transcriptome sequencing analysis, q-PCR and western blot analysis before and after TNF-α preconditioning. Furthermore, exosomes derived from TNF-α preconditioned IPFP-MSCs (IPFP-MSC-EXOsTNF−α) were administered intra-articularly in an OA mouse model, and subsequent evaluations were conducted to assess joint pathology and gait alterations. The expression of proteins involved in the maintenance of cartilage homeostasis within the exosomes was determined through proteomic analysis.ResultsThe preconditioning with TNF-α significantly enhanced the exosome secretion of IPFP-MSCs compared to unpreconditioned MSCs. The potential mechanism involved the activation of the PI3K/AKT signaling pathway in IPFP-MSCs by TNF-α precondition, leading to an up-regulation of autophagy-related protein 16 like 1(ATG16L1) levels, which subsequently facilitated exosome secretion. The intra-articular administration of IPFP-MSC-EXOsTNF−α demonstrated superior efficacy in ameliorating pathological changes in the joints of OA mice. The preconditioning of TNF-α enhanced the up-regulation of low-density lipoprotein receptor-related protein 1 (LRP1) levels in IPFP-MSC-EXOsTNF−α, thereby exerting chondroprotective effects.ConclusionTNF-α preconditioning constitutes an effective and promising method for optimizing the therapeutic effects of IPFP-MSCs derived exosomes in the treatment of OA.Graphical

Osteoarthritis induced by monosodium iodoacetate model

Objectives: this study aimed to highlight the evolution of the osteoarthritis (OA) model induced by monosodium iodoacetate (MIA) and its collaboration with the knowledge of the pathophysiology of inflammation, hypernociception and cartilage degeneration. Methods: PubMed and Science Direct were used with the descriptors: knee osteoarthritis or osteoarthritis of ankle) and (rat or osteoarthritis induced by monoiodoacetate) and (animal model of osteoarthritis or joint nociception). Studies containing rats, mice, and monoiodoacetate-induced osteoathritis were included. Exclusion criteria were: Animal models of osteoarthritis induced by destabilization; meniscectomy-induced osteoarthritis; non-invasive animal models of osteoarthritis induced by fracture, compression and tibial overload; animal models of osteoarthritis with large animals and models of osteoarthritis by papain or bacterial collagenase. We summarized studies that used MIA to induce knee or ankle OA in rats or mice and the evolution of the inflammatory markers. Results: a total of 38 original manuscripts met the inclusion criteria and were considered in the study. The model of OA induced by MIA is well-established and explored with several methodologies and has been widely used in different species. MIA induces cell death, progressive loss of chondrocytes and histological changes that mimics human OA. Studies with this model demonstrated inflammation, neurogenic hyperalgesia, release of cytokines and matrix metalloproteinases. More recently, molecular biology data confirm the activation of nuclear transcription factors, which modulates the expression of citokines in apoptotic chondrocytes. Conclusion: the MIA-induced OA has been useful in predicting several characteristics for the elucidation of osteoarthritis pathophysiology.

Targeting Fascin1 maintains chondrocytes phenotype and attenuates osteoarthritis development

Osteoarthritis (OA) is the most common form of arthritic disease, and phenotypic modification of chondrocytes is an important mechanism that contributes to the loss of cartilage homeostasis. This study identified that Fascin actin-bundling protein 1 (FSCN1) plays a pivotal role in regulating chondrocytes phenotype and maintaining cartilage homeostasis. Proteome-wide screening revealed markedly upregulated FSCN1 protein expression in human OA cartilage. FSCN1 accumulation was confirmed in the superficial layer of OA cartilage from humans and mice, primarily in dedifferentiated-like chondrocytes, associated with enhanced actin stress fiber formation and upregulated type I and III collagens. FSCN1-inducible knockout mice exhibited delayed cartilage degeneration following experimental OA surgery. Mechanistically, FSCN1 promoted actin polymerization and disrupted the inhibition of Decorin on TGF-β1, leading to excessive TGF-β1 production and ALK1/Smad1/5 signaling activation, thus, accelerated chondrocyte dedifferentiation. Intra-articular injection of FSCN1-overexpressing adeno-associated virus exacerbated OA progression in mice, which was mitigated by an ALK1 inhibitor. Moreover, FSCN1 inhibitor NP-G2-044 effectively reduced extracellular matrix degradation in OA mice, cultured human OA chondrocytes, and cartilage explants by suppressing ALK1/Smad1/5 signaling. These findings suggest that targeting FSCN1 represents a promising therapeutic approach for OA.

Postnatal deletion of Phlpp1 in chondrocytes delays post-traumatic osteoarthritis in male mice

ObjectiveOsteoarthritis is a chronic, debilitating disease that causes long-term pain and immobility. Germline deletion of Phlpp1 or administration of small molecules that inhibit Phlpp1 prevents post-traumatic osteoarthritis (PTOA) in mice. However, the chondrocyte-intrinsic role of Phlpp1 in PTOA progression is unknown. The objective of this study was to determine how postnatal, chondrocyte-directed deletion of Phlpp1 affects PTOA progression in the presence or absence of Phlpp inhibitors. DesignPhlpp1fl/fl; Agc-CreERT2 and Agc-CreERT2 mice were injected with tamoxifen at 12 weeks of age to generate Phlpp1-CKOAgcERT and control (AgcERT) groups. Male mice underwent surgery to destabilize the medial meniscus (DMM) at 17 weeks of age. A separate cohort of male Phlpp1-CKOAgcERT mice were administered an intra-articular injection of NSC117079, a Phlpp1/2 inhibitor, or saline seven weeks after DMM surgery. Activity and mechanical allodynia were monitored throughout the experiment and cartilage damage was evaluated 12 weeks post-surgery. ResultsPhlpp1-CKOAgcERT mice had less cartilage damage than AgcERT littermates 12 weeks after DMM surgery but exhibited no differences in activity. Prg4 expression was also higher in articular chondrocytes of Phlpp1-CKOAgcERT mice. Intra-articular administration of NSC117079 to Phlpp1-CKOAgcERT mice improved cartilage structure, subchondral bone sclerosis, and mechanical allodynia at 12 weeks post-DMM. ConclusionsPostnatal deletion of Phlpp1 in chondrocytes attenuates DMM-induced cartilage damage and subchondral bone sclerosis but does not prevent pain-related behaviors. Intra-articular injection of Phlpp inhibitors delays mechanical allodynia in Phlpp1-CKOAgcERT mice. These data indicate that Phlpp1 in chondrocytes affects articular cartilage structure after injury, but pain-related behaviors are controlled by Phlpp1 or Phlpp2 in other cell types.