Urolithin A improves mitochondrial health, reduces cartilage degeneration, and alleviates pain in osteoarthritis

Mitochondria-rich extracellular vesicles derived from the culture supernatant of human synovial Fluid-derived mesenchymal stem cells Inhibited senescence of Stressed/inflammatory Licensed chondrocytes and Delayed Osteoarthritis progression

BACKGROUND

Mitochondrial dysfunction induces chondrocyte senescence, thereby precipitating articular cartilage (AC) degeneration in the pathogenesis of osteoarthritis (OA). Although the transfer of mitochondria from mesenchymal stem cells (MSCs) to host cells and their potential protective role have been demonstrated, whether MSCs can alleviate chondrocyte mitochondrial dysfunction or reverse OA progression remains unclear.

METHODS

A mitochondrial tracer was used to investigate the transfer of mitochondria-rich extracellular vesicles (MEV) derived from the culture supernatant of human synovial fluid-derived mesenchymal stem cells (hSF-MSCs). Human articular chondrocytes (hACs) impaired by oxidative stress co-incubated with MEV were used for experimental research in vitro. Healthy hACs and stressed hACs were cultured separately acting as the control groups. The MEV was injected into the OA rats' knee joint serving as experimental group. Healthy and OA rats were served as the control groups. Quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot (WB), enzyme- linked immunosorbent assay (ELISA), flow cytometry (FC), immunofluorescence (IF), fluorescence spectrophotometer (FS), immunohistochemistry (IHC) and other methods are used to analyze the effect of MEV on hACs and OA progression.

RESULTS

MEV derived from hSF-MSCs could transfer into hACs. Compared to the negative control group, co-incubation with MEV resulted in a significant down-regulation of oxidative stress markers and senescence-associated proteins in hACs, while improved mitochondrial function of hACs. Moreover, the MEV could traverse the dense interstitial layer and migrate towards the deeper cartilage, while intra-articular injection of MEV could effectively attenuate AC degeneration.

CONCLUSION

The transfer of MEV derived from hSF-MSCs represents a promising strategy for safeguarding AC, thereby offering a potential avenue and mechanism for the treatment of OA.

Sulforaphane, Urolithin A, and ZLN005 induce time-dependent alterations in antioxidant capacity, mitophagy, and mitochondrial biogenesis in muscle cells

Efficient signal transduction that mediates mitochondrial turnover is a strong determinant of metabolic health in skeletal muscle. Of these pathways, our focus was aimed towards the enhancement of antioxidant capacity, mitophagy, and mitochondrial biogenesis. While physical activity is an excellent inducer of mitochondrial turnover, its ability to ubiquitously activate and enhance mitochondrial turnover prevents definitive differentiation of the contribution made by each pathway. Therefore, we employed three agents, Sulforaphane (SFN), Urolithin A (UroA), and ZLN005 (ZLN), which are activators of important biological markers involved in antioxidant signaling, mitophagy, and biogenesis, respectively. We investigated the time-dependent changes in proteins related to each mechanism in C2C12 myotubes. SFN treatment resulted in increased nuclear localization of the transcription factor Nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) after 4 ​hour (h), with subsequent 2-fold increases in the antioxidant enzymes Nicotinamide Quinone Oxidoreductase 1 (NQO1) and Heme-Oxygenase-1 (HO-1) by 24 ​h and 48 ​h. Mitochondrial respiration and ATP production were significantly increased by both 24 h and 48 ​h. UroA showed a 2-fold increase in AMP-activated Protein Kinase (AMPK) after 4 ​h, which led to a modest 30% increase in whole cell mitophagy markers p62 and LC3, after 48 ​h. This was accompanied by a reduction in cellular Reactive Oxygen Species (ROS), detected with the CellROX Green reagent. Mitophagy flux measurements showed mitophagy activation as both LC3-II and p62 flux increased with UroA at 24-h and 48-h time points, respectively. Finally, AMPK activation was observed by 4 ​h, in addition to a 2-fold increase in Mitochondrial Transcription Factor A (TFAM) promoter activity by 24 ​h of ZLN treatment following transient transfection of a TFAM promoter-luciferase construct. Mitochondrial respiration and ATP production were enhanced by 24 ​h. Our results suggest that early time points of treatment increase upstream pathway activity, whereas later time points represent the increased phenotypic expression of related downstream markers. Our findings suggest that the spatiotemporal progression of these mechanisms following drug treatment is another important factor to consider when examining subcellular changes towards mitochondrial turnover in muscle.

Association of N, N-diethyl-m-toluamide (DEET) with arthritis among adult participants

BACKGROUND

N, N-diethyl-m-toluamide (DEET), an active ingredient prevalent in insect repellents, has its effects on human health under ongoing debate and scrutiny.

OBJECTIVE

This study aimed to investigate the association between exposure to DEET and arthritis outcomes within the broader adult demographic, leveraging data obtained from the National Health and Nutrition Examination Survey (NHANES).

METHODS

3-diethyl-carbamoyl benzoic acid (DCBA) was used as a specific indicator of DEET exposure. Drawing on NHANES 2007-2016 data, our study incorporated 7065 adults to examine urinary DCBA impacts on arthritis risks using logistic regression and cubic spline analysis.

RESULTS

Our study included a total of 7065 patients, of which 1860 (26.33%) had arthritis. After adjusting for all covariates, the multivariate logistic regression analysis showed that high DCBA levels (>7.37 ug/L) were associated with an increased likelihood of arthritis (OR: 1.236, 95% CI: 1.037-1.474, p = 0.018). Nevertheless, participants in the highest quartile of DCBA levels (Q4) were associated with a 33.9% decreased risk of rheumatoid arthritis (OR: 0.661; 95% CI: 0.501-0.872; p = 0.003).

CONCLUSION

It was observed that increased levels of DCBA are positively associated with the prevalence of arthritis in the adult population. Conversely, high concentrations of DCBA showed a reverse correlation with the prevalence of rheumatoid arthritis.

GATD3A-deficiency-induced mitochondrial dysfunction facilitates senescence of fibroblast-like synoviocytes and osteoarthritis progression

Accumulating evidence indicates that cellular senescence is closely associated with osteoarthritis. However, there is limited research on the mechanisms underlying fibroblast-like synoviocyte senescence and its impact on osteoarthritis progression. Here, we elucidate a positive correlation between fibroblast-like synoviocyte senescence and osteoarthritis progression and reveal that GATD3A deficiency induces fibroblast-like synoviocyte senescence. Mechanistically, GATD3A deficiency enhances the binding of Sirt3 to MDH2, leading to deacetylation and decreased activity of MDH2. Reduced MDH2 activity impairs tricarboxylic acid cycle flux, resulting in mitochondrial dysfunction and fibroblast-like synoviocyte senescence. Intra-articular injection of recombinant adeno-associated virus carrying GATD3A significantly alleviates the osteoarthritis phenotype in male mice. This study increases our current understanding of GATD3A function. In particular, we reveal a novel mechanism of fibroblast-like synoviocyte senescence, suggesting that targeting GATD3A is a potential therapeutic approach for osteoarthritis.

True-bone-ceramics / type I collagen scaffolds for repairing osteochondral defect

In recent years, the incidence of cartilage defects has increased dramatically, and its etiology is complex and varied. Osteochondritis dissecans (OCD), as one of the main etiologies, damages both cartilage and bone tissues and can progress to severe osteoarthritis, which has been one of the difficult problems for clinicians. The vigorous development of material science and tissue engineering provides new ideas for the treatment of OCD, in which the selection of scaffold materials is particularly important. In this study, true-bone-ceramics (TBC), which has good mechanical strength and osteoconductivity, and type I collagen (COL1), which has excellent biocompatibility, were chosen as scaffold materials to co-construct the TBC/COL1 scaffold for osteochondral repair. In order to ensure the most appropriate collagen coating concentration, three experimental groups (1, 5, 12 mg/ml) were set up. Through the physicochemical property test, biocompatibility analysis and in vivo implantation experiments of composite scaffolds, 12 mg/ml TBC/COL1 scaffolds present the best repair effect among the three groups.

Urolithin A improves myocardial ischemia-reperfusion injury by attenuating oxidative stress and ferroptosis through Nrf2 pathway

Ischemia/reperfusion (I/R) injury has been demonstrated to exert a significant role in acute myocardial infarction (AMI), which constitutes a crucial cause of AMI. Ferroptosis represents a novel form of cell death that is intimately linked to myocardial ischemia-reperfusion (MIR) injury. Urolithin A (UA), an intestinal metabolite of ellagitannins, has not been fully elucidated for its role in MIR injury. In the present study, we analyzed the effects of UA on ischemia-reperfusion-induced oxidative stress and ferroptosis both in vitro and in vivo, and explored the potential mechanisms of UA action. The results indicated that UA was capable of protecting the heart from ischemia-reperfusion injury and enhancing cardiac function both in vitro and in vivo. In addition, UA also attenuated oxidative stress, mitochondrial damage, and ferroptosis during MIR. Mechanistically, UA not only augmented the Nrf2 expression but also promoted Nrf2 entry into the nucleus and activated the downstream antioxidant defense system. Moreover, after the inhibition of Nrf2, the myocardial protective function of UA was lost, and its function of attenuating oxidative stress and ferroptosis was suppressed. In conclusion, we found that UA protected the heart from ischemia-reperfusion injury by attenuating oxidative stress and ferroptosis through the Nrf2 signaling pathway, suggesting that UA might be a potential therapeutic agent for the treatment of AMI.

RNA-binding protein HNRNPD promotes chondrocyte senescence and osteoarthritis progression through upregulating FOXM1

Osteoarthritis (OA) is a common age-related disease that is correlated with a high number of senescent chondrocytes in joint tissues. Heterogeneous nuclear ribonucleoprotein D (HNRNPD) is an RNA-binding protein whose expression imbalance is associated with cell senescence, but the role of HNRNPD in the occurrence and development of OA has not been reported. In this study, HNRNPD was found to be associated with the chondrocyte senescence process. We determined the factors at the posttranscriptional level that regulated the expression of the genes that induce OA and found that HNRNPD was specifically highly expressed in OA-induced rat cartilage and in human OA cartilage. Recombinant adeno-associated virus (rAAV)-mediated HNRNPD gene overexpression alone did not significantly regulate the occurrence and development of OA in the physiological state of the joint. However, rAAV-HNRNPD significantly exacerbated experimental OA in rats subjected to destabilization of the medial meniscus. Overexpression of HNRNPD promoted mitochondrial dysfunction and the expression of FOXM1, which acts as a direct target. Furthermore, downregulation of FOXM1 in chondrocytes weakened the HNRNPD-mediated promotion of chondrocyte senescence and mitochondrial dysfunction. Our results suggest that the RNA-binding protein HNRNPD promotes chondrocyte senescence in the pathology of OA by upregulating FOXM1.

Controlled Release of Ceria and Ferric Oxide Nanoparticles via Collagen Hydrogel for Enhanced Osteoarthritis Therapy

Osteoarthritis (OA), characterized by chronic inflammation and cartilage degeneration, significantly affects over 500 million people globally. Nanoparticles have emerged as promising treatments for OA; however, current strategies often employ a single type of nanoparticle targeting specific disease stages, limiting sustained therapeutic efficacy. In this study, a novel collagen hydrogel is introduced, thiol crosslinked collagen-cerium oxide-poly(D,L-lactic-co-glycolic acid) microspheres encapsulating nanoparticles (CSH-CeO2-pFe2O3), designed for the controlled release of cerium oxide (CeO2) and ferric oxide (Fe2O3) nanoparticles for comprehensive OA management. The sulfhydryl cross-linked collagen matrix embeds CeO2 nanoparticles and poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres encapsulating Fe2O3 nanoparticles. The CSH-CeO2-pFe2O3 hydrogel exhibits enhanced mechanical strength and remarkable injectability, along with a significant promotion of cell adhesion, proliferation, and chondrogenic differentiation. Notably, the hydrogel demonstrates intelligent responsiveness to high levels of reactive oxygen species, initiating the rapid release of CeO2 nanoparticles to address the intense inflammatory responses of early-stage OA, followed by the sustained release of Fe2O3 nanoparticles to facilitate cartilage regeneration during the proliferative phase. In a rat model with cartilage defects, the hydrogel significantly alleviates inflammation and enhances cartilage regeneration, holding substantial potential for effectively managing the pathologically complex OA.

Procyanidin capsules provide a new option for long-term ROS scavenging in chronic inflammatory diseases

Chronic inflammatory diseases such as diabetic wounds and osteoarthritis are significant threats to human health. Failure to scavenge longstanding excessive reactive oxygen species (ROS) is an important cause of chronic inflammatory diseases, yet existing treatments that provide long-lasting therapeutic effects are limited. Here, procyanidin capsules were synthesized in a simple one-step way using calcium carbonate as a template. The biosafety of procyanidin capsules in vitro and in vivo was monitored by cytotoxicity and pathological sections. The therapeutic effect of procyanidin capsules in diabetic wounds and osteoarthritis was accessed by pathological evaluation combined with the quantification of inflammatory markers. The data showed that procyanidin capsules could long-term scavenge excessive ROS and effectively promote articular cartilage repair in osteoarthritis, accelerating diabetic wound healing. Lastly, transcriptome analysis suggested that procyanidin capsules commonly regulated adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling in diabetic wounds and osteoarthritis. This study provides a straightforward protocol for creating procyanidin capsules, while presenting a promising new therapeutic option for long-term scavenging ROS in chronic inflammatory diseases.

From dysfunction to healing: advances in mitochondrial therapy for Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint condition characterised by cartilage deterioration and changes in bone morphology, resulting in pain and impaired joint mobility. Investigation into the pathophysiological mechanisms underlying OA has highlighted the significance of mitochondrial dysfunction in its progression. Mitochondria, which are cellular organelles, play a crucial role in regulating energy metabolism, generating reactive oxygen species, and facilitating essential biological processes including apoptosis. In recent years, the utilisation of exogenous drugs and MT to improve mitochondrial function in chondrocytes has shown great promise in OA treatment. Numerous studies have investigated the potential of stem cells and extracellular vesicles in mitochondrial transfer. This review aims to explore the underlying mechanisms of mitochondrial dysfunction in OA and assess the progress in utilising mitochondrial transfer as a therapeutic approach for this disease.

IRF1-mediated upregulation of PARP12 promotes cartilage degradation by inhibiting PINK1/Parkin dependent mitophagy through ISG15 attenuating ubiquitylation and SUMOylation of MFN1/2

Osteoarthritis (OA) is an age-related cartilage-degenerating joint disease. Mitochondrial dysfunction has been reported to promote the development of OA. Poly (ADP-ribose) polymerase family member 12 (PARP12) is a key regulator of mitochondrial function, protein translation, and inflammation. However, the role of PARP12 in OA-based cartilage degradation and the underlying mechanisms are relatively unknown. Here, we first demonstrated that PARP12 inhibits mitophagy and promotes OA progression in human OA cartilage and a monosodium iodoacetate-induced rat OA model. Using mass spectrometry and co-immunoprecipitation assay, PARP12 was shown to interact with ISG15, upregulate mitofusin 1 and 2 (MFN1/2) ISGylation, which downregulated MFN1/2 ubiquitination and SUMOylation, thereby inhibiting PINK1/Parkin-dependent chondrocyte mitophagy and promoting cartilage degradation. Moreover, inflammatory cytokine-induced interferon regulatory factor 1 (IRF1) activation was required for the upregulation of PARP12 expression, and it directly bound to the PARP12 promoter to activate transcription. XAV-939 inhibited PARP12 expression and suppressed OA pathogenesis in vitro and in vivo. Clinically, PARP12 can be used to predict the severity of OA; thus, it represents a new target for the study of mitophagy and OA progression. In brief, the IRF1-mediated upregulation of PARP12 promoted cartilage degradation by inhibiting PINK1/Parkin-dependent mitophagy via ISG15-based attenuation of MFN1/2 ubiquitylation and SUMOylation. Our data provide new insights into the molecular mechanisms underlying PARP12-based regulation of mitophagy and can facilitate the development of therapeutic strategies for the treatment of OA.

Battling pain from osteoarthritis: causing novel cell death

Osteoarthritis (OA) is a significant contributor to pain and disability worldwide. Pain is the main complaint of OA patients attending the clinic and has a large impact on their quality of life and economic standards. However, existing treatments for OA-related pain have not been shown to achieve good relief. The main focus is on preventing and slowing the progression of OA so that the problem of OA pain can be resolved. Pain caused by OA is complex, with the nature, location, duration, and intensity of pain changing as the disease progresses. Previous research has highlighted the role of various forms of cell death, such as apoptosis and necrosis, in the progression of pain in OA. Emerging studies have identified additional forms of novel cell death, such as pyroptosis, ferroptosis, and necroptosis that are linked to pain in OA. Different types of cell death contribute to tissue damage in OA by impacting inflammatory responses, reactive oxygen species (ROS) production, and calcium ion levels, ultimately leading to the development of pain. Evidence suggests that targeting novel types of cell death could help alleviate pain in OA patients. This review delves into the complex mechanisms of OA pain, explores the relationship between different modes of novel cell death and pain, and proposes novel cell death as a viable strategy for the treatment of these conditions, with the goal of providing scientific references for the development of future OA pain treatments and drugs.

New insights into the mechanisms and therapeutic strategies of chondrocyte autophagy in osteoarthritis

Osteoarthritis (OA) is a chronic joint disease with an unclear cause characterized by secondary osteophytes and degenerative changes in the articular cartilage. More than 250 million people are expected to be affected by it by 2050, putting a tremendous socioeconomic strain on the entire world. OA cannot currently be treated with any effective medications that change the illness. Over time, chondrocytes undergo gradual metabolic, structural, and functional changes as a result of aging or abuse. The degenerative progression of osteoarthritis is significantly influenced by the imbalance of chondrocyte homeostasis. By continuously recycling and rebuilding macromolecules or organelles, autophagy functions as a crucial regulatory system to maintain homeostasis during an individual's growth and development. This review uses chondrocytes as its starting point and establishes a strong connection between autophagy and osteoarthritis in order to thoroughly examine the mechanisms behind chondrocyte autophagy in osteoarthritis. Biomarkers of chondrocyte autophagy will be identified, and prospective targeted medications and novel treatment approaches for slowing or preventing the course of OA will be developed based on chondrocyte senescence, autophagy, and apoptosis in OA. KEY MESSAGES: Currently, OA has not been treated with any drugs that can effectively cure it. We hope that by exploring specific targets in the course of osteoarthritis, we can promote the progress of treatment strategies. The degenerative progression of osteoarthritis is significantly influenced by the imbalance of chondrocyte balance. Through the continuous recovery and reconstruction of macromolecules or organelles, autophagy is an important regulatory system for maintaining homeostasis during individual growth and development. In this paper, the close relationship between autophagy and osteoarthritis was established with chondrocytes as the starting point, in order to further explore the mechanism of chondrocyte autophagy in osteoarthritis. The development process of osteoarthritis was studied from the perspective of chondrocytes, and the change of autophagy level had a significant impact on osteoarthritis. Chondrocyte autophagy is mainly determined by intracellular mitochondrial autophagy, so we are committed to finding relevant molecules. Through PI3K/AKT- and MAPK-related pathways, the biomarkers of chondrocyte autophagy were identified, and chondrocyte senescence, autophagy, and apoptosis based on osteoarthritis provided a constructive idea for the development of prospective targeted drugs and new therapies to slow down or prevent the progression of osteoarthritis.

Persistent Fatigue, Weakness, and Aberrant Muscle Mitochondria in Survivors of Critical COVID-19

OBJECTIVES

Persistent skeletal muscle dysfunction in survivors of critical illness due to acute respiratory failure is common, but biological data elucidating underlying mechanisms are limited. The objective of this study was to elucidate the prevalence of skeletal muscle weakness and fatigue in survivors of critical illness due to COVID-19 and determine if cellular changes associate with persistent skeletal muscle dysfunction.

DESIGN

A prospective observational study in two phases: 1) survivors of critical COVID-19 participating in physical outcome measures while attending an ICU Recovery Clinic at short-term follow-up and 2) a nested cohort of patients performed comprehensive muscle and physical function assessments with a muscle biopsy; data were compared with non-COVID controls.

SETTING

ICU Recovery Clinic and clinical laboratory.

PATIENTS/SUBJECTS

Survivors of critical COVID-19 and non-COVID controls.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred twenty patients with a median of 56 years old (interquartile range [IQR], 42-65 yr old), 43% female, and 33% individuals of underrepresented race attended follow-up 44 ± 17 days after discharge. Patients had a median Acute Physiology and Chronic Health Evaluation-II score of 24.0 (IQR, 16-29) and 98 patients (82%) required mechanical ventilation with a median duration of 14 days (IQR, 9-21 d). At short-term follow-up significant physical dysfunction was observed with 93% of patients reporting generalized fatigue and performing mean 218 ± 151 meters on 6-minute walk test (45% ± 30% of predicted). Eleven patients from this group agreed to participate in long-term assessment and muscle biopsy occurring a mean 267 ± 98 days after discharge. Muscle tissue from COVID exhibited a greater abundance of M2-like macrophages and satellite cells and lower activity of mitochondrial complex II and complex IV compared with controls.

CONCLUSIONS

Our findings suggest that aberrant repair and altered mitochondrial activity in skeletal muscle associates with long-term impairments in patients surviving an ICU admission for COVID-19.

Amyloid β accelerates age-related proteome-wide protein insolubility

Loss of proteostasis is a highly conserved feature of aging across model organisms and results in the accumulation of insoluble protein aggregates. Protein insolubility is also a unifying feature of major age-related neurodegenerative diseases, including Alzheimer's Disease (AD), in which hundreds of insoluble proteins associate with aggregated amyloid beta (Aβ) in senile plaques. Despite the connection between aging and AD risk, therapeutic approaches to date have overlooked aging-driven generalized protein insolubility as a contributing factor. However, proteins that become insoluble during aging in model organisms are capable of accelerating Aβ aggregation in vitro and lifespan in vivo. Here, using an unbiased proteomics approach, we questioned the relationship between Aβ and age-related protein insolubility. Specifically, we uncovered that Aβ expression drives proteome-wide protein insolubility in C. elegans, even in young animals, and this insoluble proteome is highly similar to the insoluble proteome driven by normal aging, this vulnerable sub-proteome we term the core insoluble proteome (CIP). We show that the CIP is enriched with proteins that modify Aβ toxicity in vivo, suggesting the possibility of a vicious feedforward cycle in the context of AD. Importantly, using human genome-wide association studies (GWAS), we show that the CIP is replete with biological processes implicated not only in neurodegenerative diseases but also across a broad array of chronic, age-related diseases (CARDs). This provides suggestive evidence that age-related loss of proteostasis could play a role in general CARD risk. Finally, we show that the geroprotective, gut-derived metabolite, Urolithin A, relieves Aβ toxicity, supporting its use in clinical trials for dementia and age-related diseases.

Effect of Urolithin A on Bovine Sperm Capacitation and In Vitro Fertilization

Reactive oxygen species (ROS) play a critical role in the functional competence of sperm cells. Conversely, excessive generation of ROS can impair sperm function, including their fertilization ability. Urolithin A (UA), a gut bacteria-derived metabolite produced from the transformation of ellagitannins, with anti-aging and antioxidant properties, was investigated for the first time in bovine sperm cells in the present study. Firstly, different doses of UA (0, 1, and 10 μM; 8-16 sessions) were used during the capacitation process of frozen-thawed bovine sperm. Sperm motility was assessed using optical microscopy and CASA. Sperm vitality (eosin-nigrosin), ROS, and ATP levels, as well as mitochondrial membrane potential (JC1) and oxygen consumption were evaluated. A second experiment to test the effect of different doses of UA (0, 1, and 10 μM; 9 sessions) in both the capacitation medium, as above, and the fertilization medium, was also implemented. The embryonic development and quality were evaluated. UA, at a concentration of 1 μM, significantly improved sperm movement quality (p < 0.03). There was a trend towards an increase in the oxygen consumption rate (OCR) of capacitated sperm with 1 μM and 10 μM UA supplementation. Moreover, an increase in ATP levels (p < 0.01) was observed, accompanied by a reduction in ROS levels at the higher UA concentration. These results suggest that UA may enhance spermatozoa mitochondrial function, modifying their metabolic activity while reducing the oxidative stress. Also, the number of produced embryos appears to be positively affected by UA supplementation, although differences between the bulls may have mitigated this effect. In conclusion, presented results further support previous findings indicating the potential therapeutic value of UA for addressing reproductive sub/infertility problems and improving ART outcomes. In addition, our results also reinforce the important bull effect on ART and that male sperm bioenergetic parameters should be used to predict spermatozoa functionality and developmental potential.

10-hydroxy-2-decenoic acid prevents osteoarthritis by targeting aspartyl β hydroxylase and inhibiting chondrocyte senescence in male mice preclinically

Osteoarthritis is a degenerative joint disease with joint pain as the main symptom, caused by fibrosis and loss of articular cartilage. Due to the complexity and heterogeneity of osteoarthritis, there is a lack of effective individualized disease-modifying osteoarthritis drugs in clinical practice. Chondrocyte senescence is reported to participate in occurrence and progression of osteoarthritis. Here we show that small molecule 10-hydroxy-2-decenoic acid suppresses cartilage degeneration and relieves pain in the chondrocytes, cartilage explants from osteoarthritis patients, surgery-induced medial meniscus destabilization or naturally aged male mice. We further confirm that 10-hydroxy-2-decenoic acid exerts a protective effect by targeting the glycosylation site in the Asp_Arg_Hydrox domain of aspartyl β-hydroxylase. Mechanistically, 10-hydroxy-2-decenoic acid alleviate cellular senescence through the ERK/p53/p21 and GSK3β/p16 pathways in the chondrocytes. Our study uncovers that 10-hydroxy-2-decenoic acid modulate cartilage metabolism by targeting aspartyl β-hydroxylase to inhibit chondrocyte senescence in osteoarthritis. 10-hydroxy-2-decenoic acid may be a promising therapeutic drug against osteoarthritis.

The common link between sleep apnea syndrome and osteoarthritis: a literature review

Patients with Osteoarthritis (OA) often also suffer from Sleep Apnea Syndrome (SAS), and many scholars have started to notice this link, although the relationship between the two is still unclear. In this review, we aim to summarize the current literature on these two diseases, integrate evidence of the OA and OSA connection, explore and discuss their potential common mechanisms, and thus identify effective treatment methods for patients with both OA and SAS. Some shared characteristics of the two conditions have been identified, notably aging and obesity as mutual risk factors. Both diseases are associated with various biological processes or molecular pathways, including mitochondrial dysfunction, reactive oxygen species production, the NF-kB pathway, HIF, IL-6, and IL-8. SAS serves as a risk factor for OA, and conversely, OA may influence the progression of SAS. The effects of OA on SAS are underreported in the literature and require more investigation. To effectively manage these patients, timely intervention for SAS is necessary while treating OA, with weight reduction being a primary requirement, alongside combined treatments such as Continuous positive airway pressure (CPAP) and medications. Additionally, numerous studies in drug development are now aimed at inhibiting or clearing certain molecular pathways, including ROS, NF-KB, IL-6, and IL-8. Improving mitochondrial function might represent a viable new strategy, with further research into mitochondrial updates or transplants being essential.

Long COVID as a disease of accelerated biological aging: An opportunity to translate geroscience interventions

It has been four years since long COVID-the protracted consequences that survivors of COVID-19 face-was first described. Yet, this entity continues to devastate the quality of life of an increasing number of COVID-19 survivors without any approved therapy and a paucity of clinical trials addressing its biological root causes. Notably, many of the symptoms of long COVID are typically seen with advancing age. Leveraging this similarity, we posit that Geroscience-which aims to target the biological drivers of aging to prevent age-associated conditions as a group-could offer promising therapeutic avenues for long COVID. Bearing this in mind, this review presents a translational framework for studying long COVID as a state of effectively accelerated biological aging, identifying research gaps and offering recommendations for future preclinical and clinical studies.

Intrauterine hyperglycemia induces SIRT3-mediated mitochondrial dysfunction: the fetal origin pathogenesis of precocious osteoarthritis

OBJECTIVE

Diabetes and other metabolic and inflammatory comorbidities are highly associated with osteoarthritis (OA). However, whether early-life hyperglycemia exposure affects susceptibility to long-term OA is still unknown. The purpose of this study was to explore the fetal origins of OA and provide insights into early-life safeguarding for individual health.

METHOD

This study utilized streptozotocin to induce intrauterine hyperglycemia and performed destabilization of the medial meniscus surgery on the knee joints of the offspring mice to induce accelerated OA. Cartilage degeneration-related markers, as well as the expression levels of mitochondrial respiratory chain complexes and mitophagy genes in the adult offspring mice, were investigated. In vitro, mitochondrial function and mitophagy of chondrocyte C28/I2 cells stimulated under high glucose conditions were also evaluated. The methylation levels of the sirt3 gene promoter region in the articular cartilage of intrauterine hyperglycemia-exposed offspring mice were further analyzed.

RESULTS

In this study, we found that the intrauterine hyperglycemic environment could lead to an increase in individual susceptibility to OA in late adulthood, mainly due to persistently low levels of Sirt3 expression. Downregulation of Sirt3 causes impaired mitophagy in chondrocytes and abnormal mitochondrial respiratory function due to a failure to clear aged and damaged mitochondria in a timely manner. Overexpressing Sirt3 at the cellular level or using Sirt3 agonists like Honokiol in mouse models can partially rescue mitophagy disorders caused by the hyperglycemic environment and thus alleviate the progression of OA.

CONCLUSION

Our study revealed a significantly increased susceptibility to OA in the gestational diabetes mellitus offspring, which is partly attributed to exposure to adverse factors in utero and ultimately to the onset of disease via epigenetic modulation.

Mitophagy in relation to chronic inflammation/ROS in aging

Various assaults on mitochondria occur during the human aging process, contributing to mitochondrial dysfunction. This mitochondrial dysfunction is intricately connected with aging and diseases associated with it. In vivo, the accumulation of defective mitochondria can precipitate inflammatory and oxidative stress, thereby accelerating aging. Mitophagy, an essential selective autophagy process, plays a crucial role in managing mitochondrial quality control and homeostasis. It is a highly specialized mechanism that systematically removes damaged or impaired mitochondria from cells, ensuring their optimal functioning and survival. By engaging in mitophagy, cells are able to maintain a balanced and stable environment, free from the potentially harmful effects of dysfunctional mitochondria. An ever-growing body of research highlights the significance of mitophagy in both aging and age-related diseases. Nonetheless, the association between mitophagy and inflammation or oxidative stress induced by mitochondrial dysfunction remains ambiguous. We review the fundamental mechanisms of mitophagy in this paper, delve into its relationship with age-related stress, and propose suggestions for future research directions.

Mitochondria-Related Gene MAOB is a Key Biomarker of Osteoarthritis and Inhibition of Its Expression Reduces LPS-induced Chondrocyte Damage

The mitochondria are an important organelle in cells responsible for producing energy, and its abnormal function is closely related to the occurrence and development of osteoarthritis. Finding key genes associated with mitochondrial dysfunction in osteoarthritis can provide new ideas for the study of its pathogenesis. Firstly, 371 differential expressed genes (DEGs) were obtained through bioinformatics analysis of the GSE12021 and GSE55235 datasets in the GEO database, and 24 mitochondria-related DEGs (Mito-DEGs) were obtained by crossing differential genes with mitochondrial related genes. Next, KEGG and GO analysis of Mito-DEGs showed that upregulated Mito-DEGs were mainly enriched in small molecule catabolic process and tryptophan metabolism, while downregulated Mito-DEGs were mainly enriched in acetyl-CoA metabolic process and fatty acid biosynthesis. Furthermore, the key genes ME2 and MAOB were obtained through protein-protein interaction network analysis and lasso cox analysis of the 24 Mito-DEGs. In addition, the comparison results of immune cell scores showed differences between T cells CD4 memory resting, T cells regulatory (Tregs), Mast cells resting, and Mast cells activated in the OA group and the control group. More importantly, the potential regulatory mechanisms of key genes were studied through GSEA analysis and their correlation with immune infiltrating cells, immune checkpoints, m6A, and ferroptosis. Finally, in LPS-induced C28/I2 cells, silencing MAOB reduced inflammation injury and inhibited mitochondrial damage. Our research findings suggest that MAOB may hold potential as a target for the diagnosis and treatment of osteoarthritis.

The role and intervention of mitochondrial metabolism in osteoarthritis

Osteoarthritis (OA), a prevalent degenerative joint disease, affects a substantial global population. Despite the elusive etiology of OA, recent investigations have implicated mitochondrial dysfunction as a significant factor in disease pathogenesis. Mitochondria, pivotal cellular organelles accountable for energy production, exert essential roles in cellular metabolism. Hence, mitochondrial dysfunction can exert broad-ranging effects on various cellular processes implicated in OA development. This comprehensive review aims to provide an overview of the metabolic alterations occurring in OA and elucidate the diverse mechanisms through which mitochondrial dysfunction can contribute to OA pathogenesis. These mechanisms encompass heightened oxidative stress and inflammation, perturbed chondrocyte metabolism, and compromised autophagy. Furthermore, this review will explore potential interventions targeting mitochondrial metabolism as means to impede or decelerate the progression of OA. In summary, this review offers a comprehensive understanding of the involvement of mitochondrial metabolism in OA and underscores prospective intervention strategies.

Lubricating Microneedles System with Multistage Sustained Drug Delivery for the Treatment of Osteoarthritis

Osteoarthritis (OA) is a typical joint degenerative disease that is prevalent worldwide and significantly affects the normal activities of patients. Traditional treatments using diclofenac (DCF) as an anti-inflammatory drug by oral administration and transdermal delivery have many inherent deficiencies. In this study, a lubricating microneedles (MNs) system for the treatment of osteoarthritis with multistage sustained drug delivery and great reduction in skin damage during MNs penetration is developed. The bilayer dissolvable MNs system, namely HA-DCF@PDMPC, is prepared by designating the composite material of hyaluronic acid (HA) and covalently conjugated drug compound (HA-DCF) as the MNs tips and then modifying the surface of MNs tips with a self-adhesive lubricating copolymer (PDMPC). The MNs system is designed to achieve sustained drug release of DCF via ester bond hydrolysis, physical diffusion from MNs tips, and breakthrough of lubrication coating. Additionally, skin damage is reduced due to the presence of the lubrication coating on the superficial surface. Therefore, the lubricating MNs with multistage sustained drug delivery show good compliance as a transdermal patch for OA treatment, which is validated from anti-inflammatory cell tests and therapeutic animal experiments, down-regulating the expression levels of pro-inflammatory factors and alleviating articular cartilage destruction.

Increased Glycolytic Activity Is Part of Impeded M1(LPS) Macrophage Polarization in the Presence of Urolithin A

Urolithin A is a gut metabolite of ellagitannins and reported to confer health benefits, e.g., by increased clearance of damaged mitochondria by macroautophagy or curbed inflammation. One targeted cell type are macrophages, which are plastic and able to adopt pro- or anti-inflammatory polarization states, usually assigned as M1 and M2 macrophages, respectively. This flexibility is tightly coupled to characteristic shifts in metabolism, such as increased glycolysis in M1 macrophages, and protein expression upon appropriate stimulation. This study aimed at investigating whether the anti-inflammatory properties of U: rolithin A may be driven by metabolic alterations in cultivated murine M1(lipopolysaccharide) macrophages. Expression and extracellular flux analyses showed that urolithin A led to reduced il1β, il6, and nos2 expression and boosted glycolytic activity in M1(lipopolysaccharide) macrophages. The pro-glycolytic feature of UROLITHIN A: occurred in order to causally contribute to its anti-inflammatory potential, based on experiments in cells with impeded glycolysis. Mdivi, an inhibitor of mitochondrial fission, blunted increased glycolytic activity and reduced M1 marker expression in M1(lipopolysaccharide/UROLITHIN A: ), indicating that segregation of mitochondria was a prerequisite for both actions of UROLITHIN A: . Overall, we uncovered a so far unappreciated metabolic facet within the anti-inflammatory activity of UROLITHIN A: and call for caution about the simplified notion of increased aerobic glycolysis as an inevitably proinflammatory feature in macrophages upon exposure to natural products.

Mitochondrial DNA drives neuroinflammation through the cGAS-IFN signaling pathway in the spinal cord of neuropathic pain mice

Neuroinflammation is pivotal in the development of neuropathic pain (NeP). While mitochondrial deoxyribonucleic acid (mtDNA) and cyclic GMP-AMP synthase (cGAS) are recognized for inducing inflammation in various neurological disorders, their involvement in NeP remains ambiguous. In this study, we examined: (1) the changes in mtDNA and cGAS in mice with NeP induced by chronic constriction injury (CCI) of the sciatic nerve, whether mtDNA triggers inflammation via the cGAS signaling; (2) the effects of RU.521, a cGAS antagonist, on CCI-induced nociception (allodynia and hyperalgesia) and relative inflammatory protein expression; (3) the activation of microglia and the cGAS-IFN pathway mediated by mtDNA in BV2 cell; (4) the effect of RU.521 on mtDNA-induced inflammatory response in BV2 cells. Results revealed reduced mtDNA levels in the sciatic nerve but increased levels in the spinal cord of CCI mice, along with elevated cGAS expression and inflammatory factors. RU.521 alleviated nociceptive behaviors in CCI mice, possibly by normalizing cGAS levels and suppressing inflammation. Neuron-derived mtDNA provoked cellular activation and upregulated cGAS signaling in BV2 cells. Additionally, RU.521 and DNase I effectively inhibited cGAS-induced inflammation. These findings underscore the critical role of mtDNA accumulation and mtDNA-mediated cGAS signaling in NeP development after peripheral nerve injury.

The metabolic characteristics and changes of chondrocytes in vivo and in vitro in osteoarthritis

Osteoarthritis (OA) is an intricate pathological condition that primarily affects the entire synovial joint, especially the hip, hand, and knee joints. This results in inflammation in the synovium and osteochondral injuries, ultimately causing functional limitations and joint dysfunction. The key mechanism responsible for maintaining articular cartilage function is chondrocyte metabolism, which involves energy generation through glycolysis, oxidative phosphorylation, and other metabolic pathways. Some studies have shown that chondrocytes in OA exhibit increased glycolytic activity, leading to elevated lactate production and decreased cartilage matrix synthesis. In OA cartilage, chondrocytes display alterations in mitochondrial activity, such as decreased ATP generation and increased oxidative stress, which can contribute to cartilage deterioration. Chondrocyte metabolism also involves anabolic processes for extracellular matrix substrate production and energy generation. During OA, chondrocytes undergo considerable metabolic changes in different aspects, leading to articular cartilage homeostasis deterioration. Numerous studies have been carried out to provide tangible therapies for OA by using various models in vivo and in vitro targeting chondrocyte metabolism, although there are still certain limitations. With growing evidence indicating the essential role of chondrocyte metabolism in disease etiology, this literature review explores the metabolic characteristics and changes of chondrocytes in the presence of OA, both in vivo and in vitro. To provide insight into the complex metabolic reprogramming crucial in chondrocytes during OA progression, we investigate the dynamic interaction between metabolic pathways, such as glycolysis, lipid metabolism, and mitochondrial function. In addition, this review highlights prospective future research directions for novel approaches to diagnosis and treatment. Adopting a multifaceted strategy, our review aims to offer a comprehensive understanding of the metabolic intricacies within chondrocytes in OA, with the ultimate goal of identifying therapeutic targets capable of modulating chondrocyte metabolism for the treatment of OA.

Exosomes derived from miR-146a-overexpressing fibroblast-like synoviocytes in cartilage degradation and macrophage M1 polarization: a novel protective agent for osteoarthritis?

Introduction

Pathological changes in the articular cartilage (AC) and synovium are major manifestations of osteoarthritis (OA) and are strongly associated with pain and functional limitations. Exosome-derived microRNAs (miRNAs) are crucial regulatory factors in intercellular communication and can influence the progression of OA by participating in the degradation of chondrocytes and the phenotypic transformation in the polarization of synovial macrophages. However, the specific relationships and pathways of action of exosomal miRNAs in the pathological progression of OA in both cartilage and synovium remain unclear.

Methods

This study evaluates the effects of fibroblast-like synoviocyte (FLS)-derived exosomes (FLS-Exos), influenced by miR-146a, on AC degradation and synovial macrophage polarization. We investigated the targeted relationship between miR-146a and TRAF6, both in vivo and in vitro, along with the involvement of the NF-κB signaling pathway.

Results

The expression of miR-146a in the synovial exosomes of OA rats was significantly higher than in healthy rats. In vitro, the upregulation of miR-146a reduced chondrocyte apoptosis, whereas its downregulation had the opposite effect. In vivo, exosomes derived from miR-146a-overexpressing FLSs (miR-146a-FLS-Exos) reduced AC injury and chondrocyte apoptosis in OA. Furthermore, synovial proliferation was reduced, and the polarization of synovial macrophages shifted from M1 to M2. Mechanistically, the expression of TRAF6 was inhibited by targeting miR-146a, thereby modulating the Toll-like receptor 4/TRAF6/NF-κB pathway in the innate immune response.

Discussion

These findings suggest that miR-146a, mediated through FLS-Exos, may alleviate OA progression by modulating cartilage degradation and macrophage polarization, implicating the NF-κB pathway in the innate immune response. These insights highlight the therapeutic potential of miR-146a as a protective agent in OA, underscoring the importance of exosomal miRNAs in the pathogenesis and potential treatment of the disease.

Probiotics, prebiotics, synbiotics and other microbiome-based innovative therapeutics to mitigate obesity and enhance longevity via the gut-brain axis

The global prevalence of obesity currently exceeds 1 billion people and is accompanied by an increase in the aging population. Obesity and aging share many hallmarks and are leading risk factors for cardiometabolic disease and premature death. Current anti-obesity and pro-longevity pharmacotherapies are limited by side effects, warranting the development of novel therapies. The gut microbiota plays a major role in human health and disease, with a dysbiotic composition evident in obese and aged individuals. The bidirectional communication system between the gut and the central nervous system, known as the gut-brain axis, may link obesity to unhealthy aging. Modulating the gut with microbiome-targeted therapies, such as biotics, is a novel strategy to treat and/or manage obesity and promote longevity. Biotics represent material derived from living or once-living organisms, many of which have therapeutic effects. Pre-, pro-, syn- and post-biotics may beneficially modulate gut microbial composition and function to improve obesity and the aging process. However, the investigation of biotics as next-generation therapeutics has only just begun. Further research is needed to identify therapeutic biotics and understand their mechanisms of action. Investigating the function of the gut-brain axis in obesity and aging may lead to novel therapeutic strategies for obese, aged and comorbid (e.g., sarcopenic obese) patient populations. This review discusses the interrelationship between obesity and aging, with a particular emphasis on the gut microbiome, and presents biotics as novel therapeutic agents for obesity, aging and related disease states.

Integration of metabolomics and transcriptomics provides insights into the molecular mechanism of temporomandibular joint osteoarthritis

The deficiency of clinically specific biomarkers has made it difficult to achieve an accurate diagnosis of temporomandibular joint osteoarthritis (TMJ-OA) and the insufficient comprehension of the pathogenesis of the pathogenesis of TMJ-OA has posed challenges in advancing therapeutic measures. The combined use of metabolomics and transcriptomics technologies presents a highly effective method for identifying vital metabolic pathways and key genes in TMJ-OA patients. In this study, an analysis of synovial fluid untargeted metabolomics of 6 TMJ-OA groups and 6 temporomandibular joint reducible anterior disc displacement (TMJ-DD) groups was conducted using liquid and gas chromatography mass spectrometry (LC/GC-MS). The differential metabolites (DMs) between TMJ-OA and TMJ-DD groups were analyzed through multivariate analysis. Meanwhile, a transcriptomic dataset (GSE205389) was obtained from the GEO database to analyze the differential metabolism-related genes (DE-MTGs) between TMJ-OA and TMJ-DD groups. Finally, an integrated analysis of DMs and DE-MTGs was carried out to investigate the molecular mechanisms associated with TMJ-OA. The analysis revealed significant differences in the levels of 46 DMs between TMJ-OA and TMJ-DD groups, of which 3 metabolites (L-carnitine, taurine, and adenosine) were identified as potential biomarkers for TMJ-OA. Collectively, differential expression analysis identified 20 DE-MTGs. Furthermore, the integration of metabolomics and transcriptomics analysis revealed that the tricarboxylic acid (TCA) cycle, alanine, aspartate and glutamate metabolism, ferroptosis were significantly enriched. This study provides valuable insights into the metabolic abnormalities and associated pathogenic mechanisms, improving our understanding of TMJOA etiopathogenesis and facilitating potential target screening for therapeutic intervention.

Novel insights into the role of ubiquitination in osteoarthritis

Ubiquitination (Ub) and deubiquitination are crucial post-translational modifications (PTMs) that precisely regulate protein degradation. Under the catalysis of a cascade of E1-E2-E3 ubiquitin enzymes, ubiquitination extensively regulates protein degradation exerting direct impact on various cellular processes, while deubiquitination opposes the effect of ubiquitination and prevents proteins from degradation. Notably, such dynamic modifications have been widely investigated to be implicated in cell cycle, transcriptional regulation, apoptosis and so on. Therefore, dysregulation of ubiquitination and deubiquitination could lead to certain diseases through abnormal protein accumulation and clearance. Increasing researches have revealed that the dysregulation of catalytic regulators of ubiquitination and deubiquitination triggers imbalance of cartilage homeostasis that promotes osteoarthritis (OA) progression. Hence, it is now believed that targeting on Ub enzymes and deubiquitinating enzymes (DUBs) would provide potential therapeutic pathways. In the following sections, we will summarize the biological role of Ub enzymes and DUBs in the development and progression of OA by focusing on the updating researches, with the aim of deepening our understanding of the underlying molecular mechanism of OA pathogenesis concerning ubiquitination and deubiquitination, so as to explore novel potential therapeutic targets of OA treatment.

TGF-β3 mediates mitochondrial dynamics through the p-Smad3/AMPK pathway

It is well recognized that mitochondrial dynamics plays a vital role in cartilage physiology. Any perturbation in mitochondrial dynamics could cause disorders in cartilage metabolism and even lead to the occurrence of cartilage diseases such as osteoarthritis (OA). TGF-β3, as an important growth factor that appears in the joints of OA disease, shows its great potential in chondrocyte growth and metabolism. Nevertheless, the role of TGF-β3 on mitochondrial dynamics is still not well understood. Here we aimed to investigate the effect of TGF-β3 on mitochondrial dynamics of chondrocytes and reveal its underlying bio-mechanism. By using transmission electron microscopy (TEM) for the number and morphology of mitochondria, western blotting for the protein expressions, immunofluorescence for the cytoplasmic distributions of proteins, and RNA sequencing for the transcriptome changes related to mitochondrial dynamics. We found that TGF-β3 could increase the number of mitochondria in chondrocytes. TGF-β3-enhanced mitochondrial number was via promoting the mitochondrial fission. The mitochondrial fission induced by TGF-β3 was mediated by AMPK signaling. TGF-β3 activated canonical p-Smad3 signaling and resultantly mediated AMPK-induced mitochondrial fission. Taken together, these results elucidate an understanding of the role of TGF-β3 on mitochondrial dynamics in chondrocytes and provide potential cues for therapeutic strategies in cartilage injury and OA disease in terms of energy metabolism.

Koumine inhibits IL-1β-induced chondrocyte inflammation and ameliorates extracellular matrix degradation in osteoarthritic cartilage through activation of PINK1/Parkin-mediated mitochondrial autophagy

Osteoarthritis (OA) is a degenerative joint disease, Increasingly, mitochondrial autophagy has been found to play an important regulatory role in the prevention and treatment of osteoarthritis. Koumine is a bioactive alkaloid extracted from the plant Gelsemium elegans. In previous research, Koumine was found to have potential in improving the progression of OA in rats. However, the specific mechanism of its action has not been fully explained. Therefore, the aim of this study was to investigate whether Koumine can alleviate OA in rats by influencing mitochondrial autophagy. In the in vitro study, rat chondrocytes (RCCS-1) were induced with IL-1β (10 ng/mL) to induce inflammation, and Koumine (50 μg/mL) was co-treated. In the in vivo study, a rat OA model was established by intra-articular injection of 2% papain, and Koumine was administered orally (1 mg/kg, once daily for two weeks). It was found that Koumine effectively reduced cartilage erosion in rats with osteoarthritis. Additionally, it decreased the levels of inflammatory factors such as IL-1β, IL-6, and extracellular matrix (ECM) components MMP13 and ADAMTS5 in chondrocytes and articular cartilage tissue, while increasing the level of Collagen II.Koumine inhibited the production of reactive oxygen species (ROS) in cartilage tissue and increased the number of autophagosomes in chondrocytes and articular cartilage tissue. Additionally, it upregulated the expression of mitochondrial autophagy proteins LC3Ⅱ/Ⅰ, PINK1, Parkin, and Drp1. The administration of Mdivi-1 (50 μM) reversed the enhanced effect of Koumine on mitochondrial autophagy, as well as its anti-inflammatory and anti-ECM degradation effects in rats with OA. These findings suggest that Koumine can alleviate chondrocyte inflammation and improve the progression of OA in rats by activating PINK1/Parkin-mediated mitochondrial autophagy.

The NLRX1-SLC39A7 complex orchestrates mitochondrial dynamics and mitophagy to rejuvenate intervertebral disc by modulating mitochondrial Zn2+ trafficking

Intervertebral disc degeneration (IDD) is the most critical pathological factor in the development of low back pain. The maintenance of nucleus pulposus (NP) cell and intervertebral disc integrity benefits largely from well-controlled mitochondrial quality, surveilled by mitochondrial dynamics (fission and fusion) and mitophagy, but the outcome is cellular context-dependent that remain to be clarified. Our studies revealed that the loss of NLRX1 is correlated with NP cell senescence and IDD progression, which involve disordered mitochondrial quality. Further using animal and in vitro tissue and cell models, we demonstrated that NLRX1 could facilitate mitochondrial quality by coupling mitochondrial dynamic factors (p-DNM1L, L-OPA1:S-OPA1, OMA1) and mitophagy activity. Conversely, mitochondrial collapse occurred in NLRX1-defective NP cells and switched on the compensatory PINK1-PRKN pathway that led to excessive mitophagy and aggressive NP cell senescence. Mechanistically, NLRX1 was originally shown to interact with zinc transporter SLC39A7 and modulate mitochondrial Zn2+ trafficking via the formation of an NLRX1-SLC39A7 complex on the mitochondrial membrane of NP cells, subsequently orchestrating mitochondrial dynamics and mitophagy. The restoration of NLRX1 function by gene overexpression or pharmacological agonist (NX-13) treatment showed great potential for regulating mitochondrial fission with synchronous fusion and mitophagy, thus sustaining mitochondrial homeostasis, ameliorating NP cell senescence and rejuvenating intervertebral discs. Collectively, our findings highlight a working model whereby the NLRX1-SLC39A7 complex coupled mitochondrial dynamics and mitophagy activity to surveil and target damaged mitochondria for degradation, which determines the beneficial function of the mitochondrial surveillance system and ultimately rejuvenates intervertebral discs.Abbreviations: 3-MA: 3-methyladenine; Baf-A1: bafilomycin A1; CDKN1A/p21: cyclin dependent kinase inhibitor 1A; CDKN2A/p16: cyclin dependent kinase inhibitor 2A; DNM1L/DRP1: dynamin 1 like; EdU: 5-Ethynyl-2'-deoxyuridine; HE: hematoxylin-eosin; IDD: intervertebral disc degeneration; IL1B/IL-1β: interleukin 1 beta; IL6: interleukin 6; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MKI67/Ki67: marker of proliferation Ki-67; LBP: low back pain; MMP: mitochondrial membrane potential; MFN1: mitofusin 1; MFN2: mitofusin 2; MFF: mitochondrial fission factor; NP: nucleus pulposus; NLRX1: NLR family member X1; OMA1: OMA1 zinc metallopeptidase; OPA1: OPA1 mitochondrial dynamin like GTPase; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxidative species; SASP: senescence-associated secretory phenotype; SA-GLB1/β-gal: senescence-associated galactosidase beta 1; SO: safranin o; TBHP: tert-butyl hydroperoxide; TP53/p53: tumor protein p53; SLC39A7/ZIP7: solute carrier family 39 member 7; TOMM20: translocase of outer mitochondrial membrane 20; TIMM23: translocase of inner mitochondrial membrane 23.

Alpha 2-adrenoceptor participates in anti-hyperalgesia by regulating metabolic demand

The α2-adrenoceptor agonist dexmedetomidine is a commonly used drug for sedatives in clinics and has analgesic effects; however, its mechanism of analgesia in the spine remains unclear. In this study, we systematically used behavioural and transcriptomic sequencing, pharmacological intervention, electrophysiological recording and ultrasound imaging to explore the analgesic effects of the α2-adrenoceptor and its molecular mechanism. Firstly, we found that spinal nerve injury changed the spinal transcriptome expression, and the differential genes were mainly related to calcium signalling and tissue metabolic pathways. In addition, α2-adrenoceptor mRNA expression was significantly upregulated, and α2-adrenoceptor was significantly colocalised with markers, particularly neuronal markers. Intrathecal dexmedetomidine suppressed neuropathic pain and acute inflammatory pain in a dose-dependent manner. The transcriptome results demonstrated that the analgesic effect of dexmedetomidine may be related to the modulation of neuronal metabolism. Weighted gene correlation network analysis indicated that turquoise, brown, yellow and grey modules were the most correlated with dexmedetomidine-induced analgesic effects. Bioinformatics also annotated the involvement of metabolic processes and neural plasticity. A cardiovascular-mitochondrial interaction was found, and ultrasound imaging revealed that injection of dexmedetomidine significantly enhanced spinal cord perfusion in rats with neuropathic pain, which might be regulated by pyruvate dehydrogenase kinase 4 (pdk4), cholesterol 25-hydroxylase (ch25 h) and GTP cyclohydrolase 1 (gch1). Increasing the perfusion doses of dexmedetomidine significantly suppressed the frequency and amplitude of spinal nerve ligation-induced miniature excitatory postsynaptic currents. Overall, dexmedetomidine exerts analgesic effects by restoring neuronal metabolic processes through agonism of the α2-adrenoceptor and subsequently inhibiting changes in synaptic plasticity.

(Poly)phenol-related gut metabotypes and human health: an update

Dietary (poly)phenols have received great interest due to their potential role in the prevention and management of non-communicable diseases. In recent years, a high inter-individual variability in the biological response to (poly)phenols has been demonstrated, which could be related to the high variability in (poly)phenol gut microbial metabolism existing within individuals. An interplay between (poly)phenols and the gut microbiota exists, with (poly)phenols being metabolised by the gut microbiota and their metabolites modulating gut microbiota diversity and composition. A number of (poly)phenol metabolising phenotypes or metabotypes have been proposed, however, potential metabotypes for most (poly)phenols have not been investigated, and the relationship between metabotypes and human health remains ambiguous. This review presents updated knowledge on the reciprocal interaction between (poly)phenols and the gut microbiome, associated gut metabotypes, and subsequent impact on human health.

Advances in the study of mitophagy in osteoarthritis

Osteoarthritis (OA), characterized by cartilage degeneration, synovial inflammation, and subchondral bone remodeling, is among the most common musculoskeletal disorders globally in people over 60 years of age. The initiation and progression of OA involves the abnormal metabolism of chondrocytes as an important pathogenic process. Cartilage degeneration features mitochondrial dysfunction as one of the important causative factors of abnormal chondrocyte metabolism. Therefore, maintaining mitochondrial homeostasis is an important strategy to mitigate OA. Mitophagy is a vital process for autophagosomes to target, engulf, and remove damaged and dysfunctional mitochondria, thereby maintaining mitochondrial homeostasis. Cumulative studies have revealed a strong association between mitophagy and OA, suggesting that the regulation of mitophagy may be a novel therapeutic direction for OA. By reviewing the literature on mitophagy and OA published in recent years, this paper elaborates the potential mechanism of mitophagy regulating OA, thus providing a theoretical basis for studies related to mitophagy to develop new treatment options for OA.

Cellulose nanocrystals-reinforced dual crosslinked double network GelMA/hyaluronic acid injectable nanocomposite cryogels with improved mechanical properties for cartilage tissue regeneration

Improvement of mechanical properties of injectable tissue engineering scaffolds is a current challenge. The objective of the current study is to produce a highly porous injectable scaffold with improved mechanical properties. For this aim, cellulose nanocrystals-reinforced dual crosslinked porous nanocomposite cryogels were prepared using chemically crosslinked methacrylated gelatin (GelMA) and ionically crosslinked hyaluronic acid (HA) through the cryogelation process. The resulting nanocomposites showed highly porous structures with interconnected porosity (>90%) and mean pore size in the range of 130-296 μm. The prepared nanocomposite containing 3%w/v of GelMA, 20 w/w% of HA, and 1%w/v of CNC showed the highest Young's modulus (10 kPa) and excellent reversibility after 90% compression and could regain its initial shape after injection by a 16-gauge needle in the aqueous media. The in vitro results demonstrated acceptable viability (>90%) and migration of the human chondrocyte cell line (C28/I2), and chondrogenic differentiation of human adipose stem cells. A two-month in vivo assay on a rabbit's ear model confirmed that the regeneration potential of the prepared cryogel is comparable to the natural autologous cartilage graft, suggesting it is a promising alternative for autografts in the treatment of cartilage defects.

Sirtuin 4 (Sirt4) downregulation contributes to chondrocyte senescence and osteoarthritis via mediating mitochondrial dysfunction

Chondrocyte senescence has recently been proposed as a key pathogenic mechanism in the etiology of osteoarthritis (OA). Nevertheless, the precise molecular mechanisms underlying chondrocyte senescence remain poorly understood. To address this knowledge gap, we conducted an investigation into the involvement of Sirtuin 4 (Sirt4) in chondrocyte senescence. Our experimental findings revealed a downregulation of Sirt4 expression in TBHP-induced senescent chondrocytes in vitro, as well as in mouse OA cartilage. Additionally, we observed that the knockdown of Sirt4 in chondrocytes promoted cellular senescence and cartilage degradation, while the overexpression of Sirt4 protected the cells against TBHP-mediated senescence of chondrocytes and cartilage degradation. Moreover, our findings revealed elevated levels of reactive oxygen species (ROS), abnormal mitochondrial morphology, compromised mitochondrial membrane potential, and reduced ATP production in Sirt4 knockdown chondrocytes, indicative of mitochondrial dysfunction. Conversely, Sirt4 overexpression successfully mitigated TBHP-induced mitochondrial dysfunction. Further analysis revealed that Sirt4 downregulation impaired the cellular capacity to eliminate damaged mitochondria by inhibiting Pink1 in chondrocytes, thereby enhancing the accumulation of ROS and facilitating chondrocyte senescence. Notably, the overexpression of Pink1 counteracted the effects of Sirt4 knockdown on mitochondrial dysfunction. Importantly, our study demonstrated the promise of gene therapy employing a lentiviral vector encoding mouse Sirt4, as it successfully preserved the integrity of articular cartilage in mouse models of OA. In conclusion, our findings provide compelling evidence that the overexpression of Sirt4 enhances mitophagy, restores mitochondrial function, and protects against chondrocyte senescence, thereby offering a novel therapeutic target and potential strategy for the treatment of OA.

Natural Activators of Autophagy

Autophagy is the process by which cell contents, such as aggregated proteins, dysfunctional organelles, and cell structures are sequestered by autophagosome and delivered to lysosomes for degradation. As a process that allows the cell to get rid of non-functional components that tend to accumulate with age, autophagy has been associated with many human diseases. In this regard, the search for autophagy activators and the study of their mechanism of action is an important task for treatment of many diseases, as well as for increasing healthy life expectancy. Plants are rich sources of autophagy activators, containing large amounts of polyphenolic compounds in their composition, which can be autophagy activators in their original form, or can be metabolized by the intestinal microbiota to active compounds. This review is devoted to the plant-based autophagy activators with emphasis on the sources of their production, mechanism of action, and application in various diseases. The review also describes companies commercializing natural autophagy activators.

Mitophagy Activation by Urolithin A to Target Muscle Aging

The age-related loss of skeletal muscle function starts from midlife and if left unaddressed can lead to an impaired quality of life. A growing body of evidence indicates that mitochondrial dysfunction is causally involved with muscle aging. Muscles are tissues with high metabolic requirements, and contain rich mitochondria supply to support their continual energy needs. Cellular mitochondrial health is maintained by expansing of the mitochondrial pool though mitochondrial biogenesis, by preserving the natural mitochondrial dynamic process, via fusion and fission, and by ensuring the removal of damaged mitochondria through mitophagy. During aging, mitophagy levels decline and negatively impact skeletal muscle performance. Nutritional and pharmacological approaches have been proposed to manage the decline in muscle function due to impaired mitochondria bioenergetics. The natural postbiotic Urolithin A has been shown to promote mitophagy, mitochondrial function and improved muscle function across species in different experimental models and across multiple clinical studies. In this review, we explore the biology of Urolithin A and the clinical evidence of its impact on promoting healthy skeletal muscles during age-associated muscle decline.

Pharmacokinetics of a Natural Self-emulsifying Reversible Hybrid-Hydrogel (N'SERH) Formulation of Full-Spectrum Boswellia serrata Oleo-Gum Resin Extract: Randomised Double-Blinded Placebo-Controlled Crossover Study

The oleo-gum-resin of Boswellia serrata, an Ayurvedic herb for the treatment of chronic inflammatory diseases, contains both volatile (terpenes) and nonvolatile (boswellic acids) molecules as responsible for its bioactivity. The present randomized, double-blinded, placebo-controlled, crossover study evaluated the human pharmacokinetics of a 'natural' hybrid-hydrogel formulation of a unique full-spectrum boswellia extract (BFQ-20) (standardized for both volatile and nonvolatile bioactives) in comparison with unformulated extract (U-BE), for the first time. Mass spectrometry coupled with LC (UPLC-MS/MS) and gas chromatography (GC-MS/MS) measurements of the plasma concentration of boswellic acids and α-thujene at different post-administration time points followed by a single dose (400 mg) of U-BE and BFQ-20, to healthy volunteers (n = 16), offered 4-fold enhancement in the overall bioavailability of boswellic acids from BFQ-20, [area under the curve (AUC) (BFQ-20) = 9484.17 ± 767.82 ng * h/mL vs. AUC (U-BE) = 2365.87 ± 346.89 ng * h/mL], with the absorption maximum (Tmax) at 6.3 h post-administration and elimination half-life (T1/2) of 15.5 h (p < 0.001). While plasma α-thujene was not detectable upon U-BE administration, BFQ-20 provided significant absorption, [AUC (BFQ-20): 298.60 ± 35.48 ng * h/mL; Cmax: 68.80 ± 18.60 ng/mL; Tmax: 4.12 ± 0.38 h; T1/2: 16.24 ± 1.12 h]. Further investigation of the anti-inflammatory effect revealed 70.5% inhibition of paw edema in rats compared to 38.0% for U-BE. In summary, the natural self-emulsifying reversible hybrid-hydrogel (N'SERH) formulation of boswellia extract using fenugreek mucilage (FenuMat®) significantly increased the solubility (58-fold), stability, and bioavailability of both the volatile and non-volatile bioactives which in turn improved the anti-inflammatory efficacy of Boswellia extract.

Moxibustion ameliorates osteoarthritis by regulating gut microbiota via impacting cAMP-related signaling pathway

BACKGROUND

Osteoarthritis (OA) is a prevalent progressive disorder. Moxibustion has found widespread use in clinical practice for OA, while its underlying mechanism remains elusive.

OBJECTIVE

To investigate whether moxibustion can ameliorate OA by influencing the metabolic processes in OA and to elucidate the specific metabolic mechanisms involved.

METHODS

C57BL/6J WT mice were randomly assigned to one of three groups: the SHAM group, the ACLT group, and the ACLT+M group. In the ACLT+M group, mice underwent moxibustion treatment at acupoints Shenshu (BL23) and Zusanli (ST36) for a continuous period of 28 days, with each session lasting 20 min. We conducted a comprehensive analysis to assess the impact of moxibustion on OA, focusing on pathological changes, intestinal flora composition, and serum metabolites.

RESULTS

Moxibustion treatment effectively mitigated OA-related pathological changes. Specifically, moxibustion treatment resulted in the amelioration of articular cartilage damage, synovial inflammation, subchondral bone sclerosis when compared to the ACLT group. Moreover, 16S rDNA sequencing analysis revealed that moxibustion treatment positively influenced the composition of the flora, making it more similar to that of the SHAM group. Notably, moxibustion treatment led to a reduction in the abundance of Ruminococcus and Proteobacteria in the intestine. In addition, non-targeted metabolomics analysis identified 254 significantly different metabolites between the groups. Based on KEGG pathway analysis and the observed impact of moxibustion on OA-related inflammation, moxibustion therapy is closely associated with the cAMP-related signaling pathway.

CONCLUSION

Moxibustion can relieve OA by regulating intestinal flora and via impacting cAMP-related signaling pathway.

Amyloid β accelerates age-related proteome-wide protein insolubility

Loss of proteostasis is a highly conserved feature of aging across model organisms and typically results in the accumulation of insoluble protein aggregates. Protein insolubility is a central feature of major age-related neurodegenerative diseases, including Alzheimer's Disease (AD), where hundreds of insoluble proteins associate with aggregated amyloid beta (Aβ) in senile plaques. Moreover, proteins that become insoluble during aging in model organisms are capable of accelerating Aβ aggregation in vitro. Despite the connection between aging and AD risk, therapeutic approaches to date have overlooked aging-driven protein insolubility as a contributory factor. Here, using an unbiased proteomics approach, we questioned the relationship between Aβ and age-related protein insolubility. We demonstrate that Aβ expression drives proteome-wide protein insolubility in C. elegans and this insoluble proteome closely resembles the insoluble proteome driven by normal aging, suggesting the possibility of a vicious feedforward cycle of aggregation in the context of AD. Importantly, using human genome-wide association studies (GWAS), we show that the CIP is replete with biological processes implicated not only in neurodegenerative diseases but also across a broad array of chronic, age-related diseases (CARDs). This provides suggestive evidence that age-related loss of proteostasis could play a role in general CARD risk. Finally, we show that the CIP is enriched with proteins that modulate the toxic effects of Aβ and that the gut-derived metabolite, Urolithin A, relieves Aβ toxicity, supporting its use in clinical trials for dementia and other age-related diseases.

New insight of the pathogenesis in osteoarthritis: the intricate interplay of ferroptosis and autophagy mediated by mitophagy/chaperone-mediated autophagy

Ferroptosis, characterized by iron accumulation and lipid peroxidation, is a form of iron-driven cell death. Mitophagy is a type of selective autophagy, where degradation of damaged mitochondria is the key mechanism for maintaining mitochondrial homeostasis. Additionally, Chaperone-mediated autophagy (CMA) is a biological process that transports individual cytoplasmic proteins to lysosomes for degradation through companion molecules such as heat shock proteins. Research has demonstrated the involvement of ferroptosis, mitophagy, and CMA in the pathological progression of Osteoarthritis (OA). Furthermore, research has indicated a significant correlation between alterations in the expression of reactive oxygen species (ROS), adenosine monophosphate (AMP)-activated protein kinase (AMPK), and hypoxia-inducible factors (HIFs) and the occurrence of OA, particularly in relation to ferroptosis and mitophagy. In light of these findings, our study aims to assess the regulatory functions of ferroptosis and mitophagy/CMA in the pathogenesis of OA. Additionally, we propose a mechanism of crosstalk between ferroptosis and mitophagy, while also examining potential pharmacological interventions for targeted therapy in OA. Ultimately, our research endeavors to offer novel insights and directions for the prevention and treatment of OA.

FUNDC1/PFKP-mediated mitophagy induced by KD025 ameliorates cartilage degeneration in osteoarthritis

Osteoarthritis (OA) is the most common joint disease, but no disease-modifying drugs have been approved for OA treatment. Mitophagy participates in mitochondrial homeostasis regulation by selectively clearing dysfunctional mitochondria, which might contribute to cartilage degeneration in OA. Here, we provide evidence of impaired mitophagy in OA chondrocytes, which exacerbates chondrocyte degeneration. Among the several classic mitophagy-regulating pathways and receptors, we found that FUNDC1 plays a key role in preserving chondrocyte homeostasis by inducing mitophagy. FUNDC1 knockdown in vitro and knockout in vivo decreased mitophagy and exacerbated mitochondrial dysfunction, exacerbating chondrocyte degeneration and OA progression. FUNDC1 overexpression via intra-articular injection of adeno-associated virus alleviated cartilage degeneration in OA. Mechanistically, our study demonstrated that PFKP interacts with and dephosphorylates FUNDC1 to induce mitophagy in chondrocytes. Further analysis identified KD025 as a candidate drug for restoring chondrocyte mitophagy by increasing the FUNDC1-PFKP interaction and thus alleviating cartilage degeneration in mice with DMM-induced OA. Our study highlights the role of the FUNDC1-PFKP interaction in chondrocyte homeostasis via mitophagy induction and identifies KD025 as a promising agent for treating OA by increasing chondrocyte mitophagy.

Retuning Mitochondrial Apoptosis/Mitophagy Balance via SIRT3-Energized and Microenvironment-Modulated Hydrogel Microspheres to Impede Osteoarthritis

Full-range therapeutic regimens for osteoarthritis (OA) should consider organs (joints)-tissues (cartilage)-cells (chondrocytes)-organelles cascade, of which the subcellular mitochondria dominate eukaryotic cells' fate, and thus causally influence OA progression. However, the dynamic regulation of mitochondrial rise and demise in impaired chondrocytes and the exact role of mitochondrial metronome sirtuins 3 (SIRT3) is not clarified. Herein, chondrocytes are treated with SIRT3 natural agonist dihydromyricetin (DMY) or chemical antagonist 3-TYP, respectively, to demonstrate the positive action of SIRT3 on preserving cartilage extracellular matrix (ECM). Molecular mechanical investigations disclose that SIRT3-induced chondroprotection depended on the repression of mitochondrial apoptosis (mtApoptosis) and the activation of mitophagy. Inspired by the high-level matrix proteinases and reactive oxygen species (ROS) in the OA environment, by anchoring gelatin methacrylate (GelMA) and benzenediboronic acid (PBA) to hyaluronic acid methacrylate (HAMA) with microfluidic technology, a dual-responsive hydrogel microsphere laden with DMY is tactfully fabricated and named as DMY@HAMA-GelMA-PBA (DMY@HGP). In vivo injection of DMY@HGP ameliorated cartilage abrasion and subchondral bone sclerosis, as well as promoted motor function recovery in post-traumatic OA (PTOA) model via recouping endogenous mtApoptosis and mitophagy balance. Overall, this study unveils a novel mitochondrial dynamic-oriented strategy, holding great promise for the precision treatment of OA.

Mitophagy in human health, ageing and disease

Maintaining optimal mitochondrial function is a feature of health. Mitophagy removes and recycles damaged mitochondria and regulates the biogenesis of new, fully functional ones preserving healthy mitochondrial functions and activities. Preclinical and clinical studies have shown that impaired mitophagy negatively affects cellular health and contributes to age-related chronic diseases. Strategies to boost mitophagy have been successfully tested in model organisms, and, recently, some have been translated into clinics. In this Review, we describe the basic mechanisms of mitophagy and how mitophagy can be assessed in human blood, the immune system and tissues, including muscle, brain and liver. We outline mitophagy's role in specific diseases and describe mitophagy-activating approaches successfully tested in humans, including exercise and nutritional and pharmacological interventions. We describe how mitophagy is connected to other features of ageing through general mechanisms such as inflammation and oxidative stress and forecast how strengthening research on mitophagy and mitophagy interventions may strongly support human health.

Pharmacological Effects of Urolithin A and Its Role in Muscle Health and Performance: Current Knowledge and Prospects

Urolithin A (UA) is a naturally occurring compound derived from the metabolism of gut microbiota, which has attracted considerable research attention due to its pharmacological effects and potential implications in muscle health and performance. Recent studies have demonstrated that Urolithin A exhibits diverse biological activities, encompassing anti-inflammatory, antioxidant, anti-tumor, and anti-aging properties. In terms of muscle health, accumulating evidence suggests that Urolithin A may promote muscle protein synthesis and muscle growth through various pathways, offering promise in mitigating muscle atrophy. Moreover, Urolithin A exhibits the potential to enhance muscle health and performance by improving mitochondrial function and regulating autophagy. Nonetheless, further comprehensive investigations are still warranted to elucidate the underlying mechanisms of Urolithin A and to assess its feasibility and safety in human subjects, thereby advancing its potential applications in the realms of muscle health and performance.

Atractylenolide-III alleviates osteoarthritis and chondrocyte senescence by targeting NF-κB signaling

Atractylenolide-III (AT-III) is well known as its role in antioxidant and anti-inflammatory. Present study was aimed to figure out its effects on osteoarthritis and potential mechanisms. Rat model, human osteoarthritis cartilage explants as well as rat/human chondrocyte cultures were prepared to test AT-III's effects on osteoarthritis progression and chondrocyte senescence. Potential targeted molecules of AT-III were predicted using network pharmacology and molecular docking, assessed by Western blotting and then verified with rescue experiments. AT-III treatment alleviated osteoarthritis severity (shown by OARSI grading score and micro-CT) and chondrocyte senescence (indexed by levels of SA-β-gal, P16, P53, MMP13, ROS and ratio of healthy/collapsed mitochondrial membrane potentials). Network pharmacology and molecular docking suggested that AT-III might play role through NF-κB pathway. Further experiments revealed that AT-III reduced phosphorylation of IKKα/β, IκBα and P65 in NF-κB pathway. As well as nuclear translocation of p65. Both in vivo and in vitro experiments indicated that AT-III's effects on osteoarthritis and anti-senescence were reversed by an NF-κB agonist. AT-III could alleviate osteoarthritis by inhibiting chondrocyte senescence through NF-κB pathway, which indicated that AT-III is a prospective drug for osteoarthritis treatment.