Decreased miR-214-3p activates NF-κB pathway and aggravates osteoarthritis progression

Rapgef3 modulates macrophage reprogramming and exacerbates synovitis and osteoarthritis under excessive mechanical loading

Evidence indicates that mechanical loading plays an important role in osteoarthritis (OA) progression, while the specific pathological changes of the synovium under excessive mechanical loading are unclear. Results showed that excessive mechanical loading caused pro-inflammation of synovial macrophages, which has been confirmed to exist in OA. High Rapgef3 expression level was found in RNA sequencing of RAW246.7 subjected to 0.5 Hz and 20% cyclic tensile strain. We verified this in the synovium of patients with OA and destabilization of the medial meniscus (DMM)-OA mice. Interestingly, the Rapgef3 content of chondrocytes was very low. Primary chondrocytes treated with Rapgef3 alone did not show metabolic phenotype, but an OA phenotype appeared when treated with Rapgef3-stimulated macrophage culture supernatant. Mechanically, excessive mechanical loading activated p65-nuclear factor κB (NF-κB) pathway through Rapgef3, which promoted the inflammation of macrophage, resulting in severe articular cartilage injury. Intra-articular Rapgef3 knockout reversed synovitis and cartilage degeneration, which might provide a therapeutic target for OA.

Therapeutic targets in aging-related osteoarthritis: A focus on the extracellular matrix homeostasis

Osteoarthritis (OA) represents a globally prevalent degenerative bone diseases and is the primary contributors to pain and disability among middle-aged and elderly people, thereby imposing significant social and economic burdens. When articular cartilage is in the aging environment, epigenetic modifications, DNA damage and mitochondrial dysfunction lead to cell senescence. Chondrocyte senescence has been identified as a pivotal event in this metabolic dysregulation of the extracellular matrix (ECM). It can affect the composition and structure of ECM, and the mechanical and biological signals transmitted by ECM to senescent chondrocytes affect their physiology and pathology. Over the past few decades, the role of ECM in aging-related OA has received increasing attention. In this review, we summarize the changes of cartilage's major ECM (type II collagen and aggrecan) and the interaction between aging and ECM in OA, and explore therapeutic strategies targeting cartilagae ECM, such as noncoding RNAs, small-molecule drugs, and mesenchymal stem cell (MSC)-derived extracellular vesicles for OA. The aim of this study was to elucidate the potential benefits of ECM-based therapies as novel strategies for the management of OA diseases.

LncRNA EMBP1 sponges miR-454-3p to upregulate IRF1 and activate NLRP3-mediated chondrocyte pyroptosis to drive osteoarthritis progression

BACKGROUND

Osteoarthritis (OA) is the most common degenerative joint disease worldwide. Studies have confirmed that pyroptosis is closely associated with the OA onset and progression, particularly via the classical pathway mediated by the NLRP3 inflammasome. However, the intrinsic regulatory mechanisms underlying pyroptosis in OA remain unclear.

METHODS

We conducted RNA sequencing (RNA-seq) analysis on clinical cartilage samples and identified hub genes connecting OA and pyroptosis. We validated NLRP3-mediated pyroptosis activation, evaluated the diagnostic potential of the hub gene, and explored its regulatory role using a papain-induced rabbit OA model and IL-1β-induced chondrocytes. Subsequently, we constructed a competitive endogenous RNA (ceRNA) network based on the hub gene and validated its competitive binding interactions and regulatory function in NLRP3-mediated pyroptosis. Additionally, hub gene interferon regulatory factor 1 (IRF1) serves as a recognized upstream regulator of the novel cell death paradigm PANoptosis, which integrates apoptosis, necrosis, and pyroptosis. We preliminarily explored the potential molecular mechanisms of PANoptosis in OA through clinical sample analysis and in vitro experiments.

RESULTS

RNA-seq revealed that IRF1, a hub gene linking OA and pyroptosis, is upregulated in OA cartilage and is associated with NLRP3, consistent with the in vivo and in vitro results. Dual-luciferase assays, clinical sample analysis, and in vitro experiments confirmed the competitive binding of the embigin pseudogene 1 (EMBP1)/miR-454-3p/IRF1 ceRNA network. Silencing EMBP1 increased miR-454-3p, inhibiting IRF1 and NLRP3-mediated pyroptosis in vitro; however, miR-454-3p inhibitor rescue experiments abolished the beneficial effects of si-EMBP1. Furthermore, we preliminarily characterized the occurrence of PANoptosis in OA and provided initial evidence suggesting a potential regulatory role for the EMBP1/miR-454-3p/IRF1 axis in this process.

CONCLUSIONS

In OA, EMBP1 acts as a sponge for miR-454-3p, inhibiting its negative regulatory effect on IRF1 and exacerbating NLRP3-mediated chondrocyte pyroptosis. Furthermore, EMBP1/miR-454-3p/IRF1-mediated pyroptosis may be integrated into the broader PANoptosis process, interacting with apoptosis and necrosis to influence OA progression.

Epigenetic Biomarkers in Temporomandibular Joint Osteoarthritis: An Emerging Target in Treatment

Osteoarthritis (OA) of the temporomandibular joint (TMJ) is a progressive disease characterized by the progressive destruction of the internal surfaces of the joint. Certain epigenetic biomarkers have been detected in TMJ-OA. We summarized the available evidence on the epigenetic biomarkers in TMJ-OA. There is an increase in the expression of non-coding RNAs related to the degradation of the extracellular matrix, chondrocyte apoptosis, and proinflammatory cytokines, while there is a decrease in the expression of those related to COL2A1, as well as the osteogenic and chondrogenic differentiation of mesenchymal stem cells. Certain methylated genes and histone modifications in TMJ-OA were also identified. In the early stage, DNA methylation was significantly decreased; that is, the expression of inflammation-related genes such as TNF and genes associated with extracellular matrix degradation, such as Adamts, were increased. While in the late stage, there was an increase in the expression of genes associated with the TGF-β and MAPK signaling pathway and angiogenesis-related genes. Although research on the role of epigenetic markers in TMJ-OA is still ongoing, the results here contribute to improving the basis for the identification of accurate diagnostic and prognostic markers and the development of new therapeutic molecules for the prevention and management of TMJ-OA. It also represents a significant advancement in elucidating its pathogenesis.

MiR-103-3p regulates chondrocyte autophagy, apoptosis, and ECM degradation through the PI3K/Akt/mTOR pathway by targeting CPEB3

BACKGROUND

Chondrocyte apoptosis is associated with the severity of cartilage destruction and matrix degeneration in the progression of osteoarthritis. Increasing evidence indicates that autophagy has a significant cytoprotective effect against chondrocyte apoptosis. Here, we investigated the role of microRNA-103-3p (miR-103-3p) in regulating chondrocyte function and elucidated the underlying mechanism.

METHODS

MiR-103-3p expression in interleukin-1β (IL-1β)-stimulated chondrocytes was evaluated using RT-qPCR. The targets of miR-103-3p predicted by online databases were verified using biotin-based pulldown assay and luciferase reporter assay. IL-1β stimulated-chondrocytes were transfected with miR-103-3p inhibitor along with siRNA targeting cytoplasmic polyadenylation element-binding protein3 (siCPEB3), the autophagy inhibitor 3-MA, or the PI3K agonist 740 Y-P. Chondrocyte proliferation was evaluated using cell counting kit-8. Apoptosis was detected by flow cytometry. The levels of apoptosis-, extracellular matrix (ECM)-, autophagy-, and the PI3K/Akt/mTOR pathway-related proteins in chondrocytes were detected using immunoblotting or immunofluorescence.

RESULTS

We found that IL-1β stimulation upregulated miR-103-3p and downregulated CPEB3 in mouse chondrocytes. Inhibiting miR-103-3p reduced IL-1β-induced apoptosis and ECM macromolecule degradation while enhancing autophagy in chondrocytes. MiR-103-3p targeted CPEB3, and its downregulation rescued the expression of level in IL-1β stimulated-chondrocytes. MiR-103-3p downregulation inhibited the PI3K/Akt/mTOR pathway in IL-1β stimulated-chondrocytes by upregulating CPEB3. 3-MA, 740 Y-P, or CPEB3 knockdown counteracted the effect of miR-103-3p downregulation on chondrocyte apoptosis, ECM macromolecule degradation, and autophagy.

CONCLUSION

Overall, inhibition of miR-103-3p reduces IL-1β-induced apoptosis and ECM macromolecule degradation in chondrocytes by enhancing autophagy through the CPEB3/PI3K/Akt/mTOR pathway.

Non-coding RNA in cartilage regeneration: regulatory mechanism and therapeutic strategies

The pathogenesis of cartilage injury and degeneration is exceptionally complex. In addition to being associated with osteoarthritis and trauma, factors such as age, gender, obesity, inflammation, and apoptosis of chondrocytes are also considered significant influencing factors. Due to the lack of direct blood supply, lymphatic circulation, and neural innervation, coupled with low metabolic activity, the self-repair capability of cartilage after injury is extremely limited, making its treatment quite challenging. Recent research indicated that ncRNA, a class of RNA transcribed from the genome that does not encode proteins, played a crucial regulatory role in various disease processes. Particularly noteworthy is its positive regulatory role in cartilage regeneration, achieved through the modulation of the inflammatory microenvironment, promotion of chondrocyte proliferation, inhibition of chondrocyte degradation, and facilitation of the recruitment and differentiation of bone marrow mesenchymal stem cells into chondrocytes. In the earlier phase, we conducted a review and outlook on therapeutic strategies for the regeneration of articular cartilage injuries. This article specifically focuses on summarizing the regulatory roles and research advancements of ncRNA in cartilage regeneration, as well as its contributions to the clinical application of gene therapy for cartilage defects.

Cell culture expansion media choice affects secretory, protective and immuno-modulatory features of adipose mesenchymal stromal cell-derived secretomes for orthopaedic applications

Introduction

Mesenchymal stromal cells (MSCs) gained attention for their anti-inflammatory and trophic properties, with musculoskeletal diseases and osteoarthritis (OA) being among the most studied conditions. Alongside cells, their released factors and extracellular vesicles (EVs), overall termed "secretome", are actively sifted being envisioned as the main therapeutic actors. In addition to standard supplementation given by foetal bovine serum (FBS) or human platelet lysate (hPL), new good manufacturing practice (GMP)-compliant serum/xeno (S/X)-free media formulations have been proposed, although their influence on MSCs phenotype and potential is scarcely described. The aim of this study is therefore to evaluate, in the OA context, the differences in secretome composition and potential after adipose-MSCs (ASCs) cultivation in both standard (FBS and hPL) and two next generation (S/X) GMP-ready supplements.

Methods

Immunophenotype and secretory ability at soluble protein and EV-related levels, including embedded miRNAs, were analysed in the secretomes by means of flow cytometry, nanoparticle tracking analysis, high throughput ELISA and qRT-PCR arrays. Secretomes effect was tested in in vitro models of chondrocytes, lymphocytes and monocytes to mimic the OA microenvironment.

Results

Within a conserved molecular signature, a divergent fingerprint emerged for ASCs' secretomes collected after expansion in standard FBS/hPL or next-generation S/X formulations. Regarding soluble factors, a less protective feature for those in the secretome collected after ASCs were cultured in S/X media emerged. Moreover, the overall message for EV-miRNAs was characterized by a preponderance of protective signals in FBS and hPL conditions in a context of general safeguard given by ASCs released molecules. This dichotomy was reflected on secretomes' potential in vitro, with expansion in hPL resulting in the most effective secretome for chondrocytes and in FBS for immune cells.

Conclusions

These data open the question about the implications from using new media for MSCs expansion for clinical application. Although the undeniable advantages for GMP compliant processes, this study results suggest that new media formulations would deserve a deep characterization to drive the choice of the most effective one tailored to each specific application.

Genetics and Epigenetics of Legg-Calvé-Perthes Disease

» Multifactorial Pathogenesis: Legg-Calvé-Perthes disease (LCPD) may result from a complex interplay of genetic, epigenetic, and environmental factors, culminating in avascular necrosis of the femoral head in children aged 4 to 10 years.» Genetic Contributions: Mutations in COL2A1 weaken cartilage integrity, and polymorphisms in IL6 drive inflammatory responses, exacerbating bone resorption and necrosis.» Role of Epigenetics: Epigenetic mechanisms, such as altered DNA methylation and miRNA dysregulation, may modulate disease progression by linking genetic susceptibility to environmental influences.» Environmental Amplifiers: Key environmental risk factors, including maternal smoking, low birth weight, and socioeconomic deprivation, may exacerbate the genetic and epigenetic predisposition to LCPD.» Future Directions: Advancements in genetic screening and epigenetic therapies, such as miRNA modulators and DNA methylation inhibitors, combined with preventive measures like improved prenatal care and reduced smoke exposure, may offer promising avenues for optimizing outcomes in LCPD.

Deciphering the role of Wnt/β-catenin and miR-214 in knee osteoarthritis: molecular and clinical insights

Introduction

Understanding the molecular mechanism underlying the pathogenesis of knee osteoarthritis (KOA) may be beneficial in fetching new therapeutics. Our study aims to investigate the implication of Wnt/ β-catenin pathway in development of KOA by detection of the downstream target genes and their crosstalk with miR-214 in patients with KOA and to correlate that with the clinical findings.

Methods

Sixty participants were involved in the study. The levels of miR-214, β-catenin, Wnt4, matrix metalloproteinase 3 (MMP3), Bax, caspase 3, and phosphorylated glycogen synthase kinase-3 beta (pGSK3β) were determined. All participants were assessed clinically and radiologically regarding knee joint pain, stiffness, range of motion, and knee medial cartilage thickness. Besides, a correlation between Western Ontario and McMaster Universities (WOMAC) score, clinical, and radiological data, and the measured parameters was conducted.

Results and discussion

Patients with KOA showed downregulated miR-214 with upregulated β-catenin, Wnt4, MMP3, Bax, caspase 3, and pGSK3β compared to healthy individuals. Statistically significant positive correlation between WOMAC score, knee joint pain regarding Visual Analogue Scale (VAS) with β-catenin, pGSK3β, Wnt4, MMP3, Bax, and caspase 3, and significant negative relationship between them and knee joint medial cartilage thickness; while there was a statistically significant negative correlation between WOMAC, and clinical findings of osteoarthritis and miR-214 and significant positive relationship between it and knee joint medial cartilage thickness. This study provides valuable insights into involvement of the Wnt/β-catenin and miR-214 in KOA pathogenesis. By targeting these molecular components, future therapeutics may modulate their activity and mitigate chondrocyte apoptosis and matrix degradation, potentially halting KOA progression.

Strontium-Alix interaction enhances exosomal miRNA selectively loading in synovial MSCs for temporomandibular joint osteoarthritis treatment

The ambiguity of etiology makes temporomandibular joint osteoarthritis (TMJOA) "difficult-to-treat". Emerging evidence underscores the therapeutic promise of exosomes in osteoarthritis management. Nonetheless, challenges such as low yields and insignificant efficacy of current exosome therapies necessitate significant advances. Addressing lower strontium (Sr) levels in arthritic synovial microenvironment, we studied the effect of Sr element on exosomes and miRNA selectively loading in synovial mesenchymal stem cells (SMSCs). Here, we developed an optimized system that boosts the yield of SMSC-derived exosomes (SMSC-EXOs) and improves their miRNA profiles with an elevated proportion of beneficial miRNAs, while reducing harmful ones by pretreating SMSCs with Sr. Compared to untreated SMSC-EXOs, Sr-pretreated SMSC-derived exosomes (Sr-SMSC-EXOs) demonstrated superior therapeutic efficacy by mitigating chondrocyte ferroptosis and reducing osteoclast-mediated joint pain in TMJOA. Our results illustrate Alix's crucial role in Sr-triggered miRNA loading, identifying miR-143-3p as a key anti-TMJOA exosomal component. Interestingly, this system is specifically oriented towards synovium-derived stem cells. The insight into trace element-driven, site-specific miRNA selectively loading in SMSC-EXOs proposes a promising therapeutic enhancement strategy for TMJOA.

Regulation of fibroblast phenotype in osteoarthritis using CDKN1A-loaded copper sulfide nanoparticles delivered by mesenchymal stem cells

This study aimed to investigate the regulation of fibroblast phenotypes by mesenchymal stem cells (MSCs) delivering copper sulfide (CuS) nanoparticles (NPs) loaded with CDKN1A plasmids and their role in cartilage repair during osteoarthritis (OA). Single-cell RNA sequencing data from the GEO database were analyzed to identify subpopulations within the OA immune microenvironment. Quality control, filtering, principal component analysis (PCA) dimensionality reduction, and tSNE clustering were performed to obtain detailed cell subtypes. Pseudotime analysis was used to understand the developmental trajectory of fibroblasts, and GO/KEGG enrichment analyses highlighted biological processes related to fibroblast function. Transcriptomic data and WGCNA identified CDKN1A as a key regulatory gene. A biomimetic CuS@CDKN1A nanosystem was constructed and loaded into MSCs to create MSCs@CuS@CDKN1A. The characterization of this system confirmed its efficient cellular uptake by fibroblasts. In vitro experiments demonstrated that MSCs@CuS@CDKN1A significantly modulated fibroblast phenotypes and improved the structure, proliferation, reduced apoptosis, and enhanced migration of IL-1β-stimulated chondrocytes. In vivo, an OA mouse model was treated with intra-articular injections of MSCs@CuS@CDKN1A. Micro-CT scans revealed a significant reduction in osteophyte formation and improved joint space compared with control groups. Histological analysis, including H&E, Safranin O-Fast Green, and toluidine blue staining, confirmed improved cartilage integrity, whereas the International Osteoarthritis Research Society (OARSI) scoring indicated reduced disease severity. Immunofluorescence showed upregulated CDKN1A expression, decreased MMP13, and reduced α-SMA expression in fibroblast subtypes. Major organs exhibited no signs of toxicity, confirming the biocompatibility and safety of the treatment. These findings suggest that MSCs@CuS@CDKN1A can effectively regulate fibroblast activity and promote cartilage repair, providing a promising therapeutic strategy for OA treatment.NEW & NOTEWORTHY This study introduces MSCs@CuS@CDKN1A, a nanoengineered MSC platform that targets fibroblast phenotypes in osteoarthritis (OA). By modulating CDKN1A expression, this innovative approach not only enhances cartilage repair but also effectively mitigates fibroblast-driven inflammation, marking a significant advancement in OA therapeutics with demonstrated efficacy and biocompatibility.

Molecular Mechanisms and Clinical Aspects of Colitis-Associated Cancer in Ulcerative Colitis

Inflammatory bowel diseases have long been recognized as entities with a higher risk of colorectal cancer. An increasing amount of information has been published regarding ulcerative colitis-associated colorectal cancer and its unique mechanisms in recent decades, as ulcerative colitis constitutes a chronic process characterized by cycles of activity and remission of unpredictable durations and intensities; cumulative genomic alterations occur during active disease and mucosal healing, resulting in a special sequence of events different to the events associated with sporadic colorectal cancer. The recognition of the core differences between sporadic colorectal cancer and colitis-associated cancer is of great importance to understand and guide the directions in which new research could be performed, and how it could be applied to current clinical scenarios. A DSS/AOM murine model has allowed for a better understanding of the pathogenic mechanisms in colitis-associated cancer, as it is currently the closest model to this unique scenario. In this review, we provide a summary of the main molecular mechanisms and the clinical aspects of colitis-associated cancer in ulcerative colitis.

CircRNA expression profiling of the rat thalamus in temporomandibular joint chronic inflammatory pain

Orofacial pain (OFP) induced by temporomandibular disorders (TMDs) is prevalent, affecting approximately 4.6 % of the population. One specific type of TMD is temporomandibular osteoarthritis (TMJOA), a common degenerative disease that significantly impacts patients' quality of life. Differentially expressed circular RNAs (DEcircRNAs) in the thalamus, which serves as a relay station in the orofacial pain transmission pathway, may play a crucial role and serve as potential target markers for inflammation and the progression of inflammatory pain in TMJOA. The aim of this study was to investigate the expression profile of circRNAs in the thalamus of TMJOA. We obtained the circRNA expression profile from the thalamus of a rat model of TMJOA through high-throughput sequencing (HT-seq) and further validated their expression using reverse transcription real-time polymerase chain reaction (RT-qPCR), followed by bioinformatics analysis of the expression data. A total of 425 circRNAs (DESeq2 p- value < 0.05, |log2FoldChange| > 0.0) were identified as significantly differentially expressed by RNA-Seq, comprising 188 up-regulated and 237 down-regulated circRNAs. After validation via RT-qPCR, we employed miRanda software to predict the binding sites of miRNAs for the identified circRNAs to further explore the functions of DEcircRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that DEcircRNAs were primarily enriched in pathways and functions related to synapse development, protein signaling and modification, 'Circadian entertainment', the 'MAPK signaling pathway', and 'Glutamatergic synapse'. These findings suggest that DEcircRNAs in the thalamus play a significant role in the progression of TMJOA and may serve as promising candidate molecular targets for gene therapy.

Alone or in combination, hyaluronic acid and chondroitin sulfate alleviate ECM degradation in osteoarthritis by inhibiting the NF-κB pathway

BACKGROUNDS

Osteoarthritis (OA) significantly impacts the elderly, leading to disability and decreased quality of life. While hyaluronic acid (HA) and chondroitin sulfate (CS) are recognized for their therapeutic potential in OA, their effects on extracellular matrix (ECM) degradation are not well understood. This study investigates the impact of HA and CS, individually and combined, on ECM degradation in OA and the underlying mechanisms.

METHODS

OA was modeled in rats through anterior cruciate ligament transection and in cells using IL-1β pretreatment. Treatments included HA and CS, alone or combined, with and without PMA (an NF-κB pathway activator). Cartilage tissue was analyzed using HE and Saffron O-fast green staining, with degradation assessed via the OARSI score. Inflammatory factors were measured by ELISA, and ECM-related proteins were detected by immunohistochemistry, immunofluorescence, and Western blotting. Chondrocyte viability was assessed using CCK8.

RESULTS

HA and CS treatments significantly reduced cartilage damage, decreased inflammatory factor release, alleviated ECM degradation, and inhibited NF-κB pathway activation compared to the OA group (P < 0.05). The combination of HA and CS further enhanced these therapeutic effects (P < 0.05). However, these benefits were reversed when PMA was introduced (P < 0.05).

CONCLUSION

HA and CS, whether used alone or in combination, mitigate ECM degradation in osteoarthritis by inhibiting the NF-κB pathway, offering potential therapeutic benefits for OA management.

CRNDE alleviates IL-1β-induced chondrocyte damage by modulating miR-31/NF-κB pathway

BACKGROUND

The long non-coding RNA CRNDE (CRNDE) has been identified as a lncRNA associated with osteoarthritis (OA), playing a role the age-related degeneration of articular cartilage. However, the precise mechanism by which CRNDE affects the physiological functions of OA chondrocytes remains unclear.

METHODS

To simulate the inflammatory conditions observed in OA, interleukin (IL)-1β-stimulated chondrocyte C-28/I2 cells were utilized. The expression levels of CRNDE and miR-31 were assessed using reverse transcription-polymerase chain reaction (RT-PCR). Chondrocyte viability and apoptosis were evaluated through CCK-8 assay and flow cytometry, respectively. The levels of IL-6, IL-1β and Tumor necrosis factor (TNF-α) were determined using enzyme-linked immunosorbent assay (ELISA). mRNA expression levels of MMP-13, Aggrecan and COL2A1 were detected by quantitative RT-PCR. Western blot analysis was performed to evaluate the protein levels of factors related to cartilage matrix degradation, including p-p65, p65 and p-IκBα of the NF-κB pathway.

RESULTS

CRNDE expression was downregulated in both OA cartilage tissues and IL-1β-stimulated chondrocytes. Overexpression of CRNDE mitigated IL-1β-stimulated chondrocytes apoptosis, inflammatory responses, and cartilage matrix degradation. Compared with healthy controls, OA tissues exhibited reduced expression of miR-31, which was negatively correlated with the expression of CRNDE. Additionally, overexpression of miR-31 partially reversed the inhibitory effects of CRNDE on apoptosis, inflammation, cartilage matrix degradation, and the inactivation of Nuclear factor (NF)-κB pathway induced by IL-1β stimulation. Moreover, silencing of CRNDE exacerbated IL-1β-induced chondrocytes damage, which was aliviated by the NF-κB pathway inhibitor, Bay 11-7082.

CONCLUSION

CRNDE alleviated IL-1β-induced injuries in OA chondrocytes by suppressing the miR-31-mediated NF-κB signaling pathway.

CircRSU1 contributes to the development of osteoarthritis via the miR-345-3p/TRAF6 signaling

OBJECTIVE

Osteoarthritis (OA) is a common type of prevalent joint diseases in the elderly. At present, circular RNAs receive more attention due to their roles during the progression of OA. In this paper, the expression profiles of circRSU1 and relevant molecules in OA patients and cell models were evaluated, and the underlying regulatory mechanisms of circRSU1-modulated OA development were also explored.

METHODS

The proliferation of chondrocytes was examined using CCK-8 assay. The levels of relevant proteins were evaluated by western blotting. The production of pro-inflammatory cytokines were measured by ELISA.

RESULTS

The results revealed upregulation of circRSU1 in OA samples, and IL-1β treatment could elevate the expression of circRSU1 in human chondrocytes. In addition, knockdown of circRSU1 abolished the dysfunctions caused by IL-1β in chondrocytes. Furthermore, miR-345-3p was identified as the novel downstream molecule of circRSU1. The levels of miR-345-3p were notably decreased in cells transfected with oe-circRSU1 and elevated in cells treated with si-circRSU1, respectively. Moreover, si-circRSU1 was able to attenuate IL-1β-induced impairments in chondrocyte via miR-345-3p. In addition, to verify the downstream mechanisms of circRSU1-modulated OA progression, TRAF6 was identified as the putative target of miR-345-3p, and miR-345-3p inhibition abolished circRSU1 knockdown-triggered downregulation of TRAF6 in IL-1β-induced OA cell model. In addition, miR-345-3p protected chondrocytes from IL-1β-induced dysfunction such as impaired ECM, reduced proliferation and upregulated apoptosis of chondrocytes, and elevated production of proinflammatory cytokines through regulating TRAF6.

CONCLUSION

In summary, circRSU1 was able to contribute to the progression of OA through regulating the miR-345-3p/TRAF6 pathway, and this novel signalling could be novel candidate for targeted therapy for OA patients.

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

INTRODUCTION

Cartilage degradation is a critical alteration in the progression of osteoarthritis (OA) due to the disorder of chondrocyte metabolic homeostasis. Autophagy plays an important role in maintaining intracellular homeostasis. Recent investigations have increasingly underscored the importance of autophagy in modulating the pathological mechanisms underlying OA. Ras-related protein Rab-1a (Rab1a) has been illustrated to regulate autophagy in many diseases but not in OA.

OBJECTIVES

This study aims to elucidate whether Rab1a could regulate the development of OA through modulation of chondrocyte autophagy and apoptosis.

METHODS

Proteomic sequencing, Western blotting, and immunohistochemistry were applied to detect the expression level of Rab1a in vitro and in vivo. Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were rigorously identified. The effects of Rab1a and the interaction between Rab1a, mTORC1, autophagy and apoptosis were explored by qPCR, Western blotting, and immunofluorescence. An experimental mouse OA model was also performed to confirm the role of Rab1a in OA pathogenesis in vivo. Histological analysis was employed to demonstrate cartilage damage.

RESULTS

Rab1a expression was significantly upregulated in inflamed chondrocytes and knee OA cartilage. Inhibition of Rab1a partially attenuated the degradation of the extracellular matrix and cell apoptosis both in vitro and in vivo, whereas overexpression of Rab1a intensified cartilage matrix degradation and cellular apoptosis. Additionally, elevated Rab1a levels were observed to suppress autophagy and activate the mTORC1-S6K signaling pathway, thereby aggravating OA pathogenesis.

CONCLUSION

The augmentation of Rab1a expression impairs autophagy and promotes apoptosis through the activation of the mTORC1-S6K signaling pathway, further exacerbating OA pathogenesis. This finding suggests that Rab1a serves as a promising and innovative therapeutic target for the prevention and treatment of OA.

Alpha-ketoglutarate ameliorates age-related and surgery induced temporomandibular joint osteoarthritis via regulating IKK/NF-κB signaling

Recent studies have shed light on the important role of aging in the pathogenesis of joint degenerative diseases and the anti-aging effect of alpha-ketoglutarate (αKG). However, whether αKG has any effect on temporomandibular joint osteoarthritis (TMJOA) is unknown. Here, we demonstrate that αKG administration improves condylar cartilage health of middle-aged/aged mice, and ameliorates pathological changes in a rat model of partial discectomy (PDE) induced TMJOA. In vitro, αKG reverses IL-1β-induced/H2O2-induced decrease of chondrogenic markers (Col2, Acan and Sox9), and inhibited IL-1β-induced/ H2O2-induced elevation of cartilage catabolic markers (ADAMTS5 and MMP13) in condylar chondrocytes. In addition, αKG downregulates senescence-associated (SA) hallmarks of aged chondrocytes, including the mRNA/protein level of SA genes (p16 and p53), markers of nuclear disorders (Lamin A/C) and SA-β-gal activities. Mechanically, αKG decreases the expressions of p-IKK and p-NF-κB, protecting TMJ from inflammation and senescence-related damage by regulating the NF-κB signaling. Collectively, our findings illuminate that αKG can ameliorate age-related TMJOA and PDE-induced TMJOA, maintain the homeostasis of cartilage matrix, and exert anti-aging effects in chondrocytes, with a promising therapeutic potential in TMJOA, especially age-related TMJOA.

Osteoarthritis rat serum-derived extracellular vesicles aggravate osteoarthritis development by inducing NLRP3-mediated pyroptotic cell death and cellular inflammation

Osteoarthritis (OA), degenerative joint disease, is the most prevalent form of arthritis worldwide. Besides its substantial burden on society, the high OA morbidity greatly diminishes patients' quality of life. According to recent research, patients-derived serum extracellular vesicles (EVs) are critically involved in sustaining the corresponding disease progression. However, limited research has fully explored the specific functions and molecular mechanisms of OA serum-derived EVs in disease progression. Consequently, we aimed to investigate the underlying mechanism of OA rats-derived serum EVs in regulating OA progression. Before constructing the exosome-cell co-culture system, EVs were extracted from OA and control rat serum and co-cultured with bone marrow mesenchymal stem cells (BM-MSCs). Western blotting (WB), RT-qPCR, and enzyme-linked immunosorbent assay (ELISA) results revealed that OA rat serum-derived EVs upregulated cell pyroptosis-related markers, including nod-Like receptor protein-3 (NLRP3), apoptosis-associated speck-like protein (ASC), gasdermin D (GSDMD), and cleaved caspase-1. The OA rat-EVs also induced the release of LDH and inflammatory cytokines, including interleukin (IL)-1β, IL-18, IL-6, and TNF-α. Additional experiments revealed that OA rat-EVs delivered miR-133a-3p to BM-MSCs and upregulated miR-133a-3p to degrade sirtuin 1 (SIRT1), and activating the downstream NF-κB signaling pathway. Furthermore, the rescuing experiments confirmed that silencing SIRT1 abrogated the miR-133a-3p-induced protective effects in OA-EVs-treated BM-MSCs. In conclusion, OA rats-derived miR-133a-3p-containing EVs modulated the downstream SIRT1/NF-κB pathway-mediated pyroptotic cell death and inflammation in OA. In other words, this study confirmed the role and underlying mechanisms by which OA-associated serum EVs regulate pyroptosis and inflammation response in OA development.

The Role of Circular RNA in the Pathogenesis of Chemotherapy-Induced Cardiotoxicity in Cancer Patients: Focus on the Pathogenesis and Future Perspective

Cardiotoxicity is a serious challenge cancer patients face today. Various factors are involved in cardiotoxicity. Circular RNAs (circRNAs) are one of the effective factors in the occurrence and prevention of cardiotoxicity. circRNAs can lead to increased proliferation, apoptosis, and regeneration of cardiomyocytes by regulating the molecular pathways, as well as increasing or decreasing gene expression; some circRNAs have a dual role in cardiomyocyte regeneration or death. Identifying each of the pathways related to these processes can be effective on managing patients and preventing cardiotoxicity. In this study, an overview of the molecular pathways involved in cardiotoxicity by circRNAs and their effects on the downstream factors have been discussed.

Bioactive Compounds and Their Chondroprotective Effects for Osteoarthritis Amelioration: A Focus on Nanotherapeutic Strategies, Epigenetic Modifications, and Gut Microbiota

In degenerative joint disease like osteoarthritis (OA), bioactive compounds like resveratrol, epigallocatechin gallate, curcumin, and other polyphenols often target various signalling pathways, including NFκB, TGFβ, and Wnt/β-catenin by executing epigenetic-modifying activities. Epigenetic modulation can target genes of disease pathophysiology via histone modification, promoter DNA methylation, and non-coding RNA expression, some of which are directly involved in OA but have been less explored. OA patients often seek options that can improve the quality of their life in addition to existing treatment with nonsteroidal anti-inflammatory drugs (NSAIDs). Although bioactive and natural compounds exhibit therapeutic potential against OA, several disadvantages loom, like insolubility and poor bioavailability. Nanoformulated bioactive compounds promise a better way to alleviate OA since they also control systemic events, including metabolic, immunological, and inflammatory responses, by modulating host gut microbiota that can regulate OA pathogenesis. Recent data suggest gut dysbiosis in OA. However, limited evidence is available on the role of bioactive compounds as epigenetic and gut modulators in ameliorating OA. Moreover, it is not known whether the effects of polyphenolic bioactive compounds on gut microbial response are mediated by epigenetic modulatory activities in OA. This narrative review highlights the nanotherapeutic strategies utilizing bioactive compounds, reporting their effects on chondrocyte growth, metabolism, and epigenetic modifications in osteoarthritis amelioration.

STUDY ON THE ROLE AND MECHANISM OF MICRORNA-650/WNT1 IN THE REPAIR OF ARTICULAR CARTILAGE INJURY

Objectives

Osteoarthritis (OA) is a degenerative disease associated with chondrocyte injury. This study investigated the dysregulation of microRNA-650 (miR-650) in cartilage tissues of patients with OA. Its function and mechanism were also investigated in OA cell models.

Methods

miR-650 levels were examined in 15 OA cartilage tissues and ten healthy cartilage tissues. SW1353 cells were used for cell function experiments and IL-1β was applied to the cells to mimic OA conditions in vitro. Cell functions such as proliferation, apoptosis, and inflammation were detected. The downstream target gene of miR-650 was identified and confirmed by bioinformatic analysis and luciferase activity assay. Rescue experiments were performed to verify the mechanism.

Results

Suppressed expression of miR-650 was tested in patients with OA and cell models. Overexpression of miR-650 increased cell proliferation but suppressed apoptosis and inflammation of SW1353. As the target gene of miR-650, WNT1 overexpression counteracted the role of miR-650 in the function of SW1353.

Conclusion

miR-650 can protect against articular cartilage injury in OA by targeting WNT1. Level of Evidence I, Experimental Study.

Adipose tissue-derived extracellular vesicles aggravate temporomandibular joint osteoarthritis associated with obesity

INTRODUCTION

Temporomandibular joint osteoarthritis (TMJ OA) is a major disease that affects maxillofacial health and is characterised by cartilage degeneration and subchondral bone remodelling. Obesity is associated with the exacerbation of pathological manifestations of TMJ OA. However, the underlying mechanism between adipose tissue and the TMJ axis remains limited.

OBJECTIVES

To evaluate the effects of obesity and the adipose tissue on the development of TMJ OA.

METHODS

The obesity-related metabolic changes in TMJ OA patients were detected by physical signs and plasma metabolites. The effects of adipose tissue-derived EVs (Ad-EVs) on TMJ OA was investigated through histological and cytological experiments as well as gene editing technology. Alterations of Ad-EVs in obese state were identified by microRNA-seq analysis and the mechanism by which EVs affect TMJ OA was explored in vitro and in vivo.

RESULTS

Obesity and the related metabolic changes were important influencing factors for TMJ OA. Ad-EVs from obese mice induced marked chondrocyte apoptosis, cartilage matrix degradation and subchondral bone remodelling, which exacerbated the development of TMJ OA. Depletion of Ad-EVs secretion by knocking out the geranylgeranyl diphosphate synthase (Ggpps) gene in adipose tissue significantly inhibited the obesity-induced aggravation of TMJ OA. MiR-3074-5p played an important role in this process .

CONCLUSIONS

Our work unveils an unknown link between obese adipose tissue and TMJ OA. Targeting the Ad-EVs and the miR-3074-5p may represent a promising therapeutic strategy for obesity-related TMJ OA.

KEY POINTS

High-fat-diet-induced obesity aggravate the progression of TMJ OA in mice. Obese adipose tissue participates in cartilage damage through the altered miRNA in extracellular vesicles. Inhibition of miR-3074-5p/SMAD4 pathway in chondrocyte alleviated the effect of HFD-EVs on TMJ OA.

Fermented Ginsenosides Alleviate Acute Liver Injury Induced by CCl4 in Mice by Regulating the AKT/mTOR Signaling Pathway

This study investigated the alleviating effect of fermented ginsenosides obtained through yeast strain fermentation transformation on acute liver injury (ALI) induced by CCl4. Strains were screened for their ability to produce β-glucosidase, the transformation ability of the strain was verified by high-performance liquid chromatography, and the Saccharomyces cerevisiae strain F6 was obtained by 26S rRNA sequencing. After fermentation by F6 strain, it was found that the content of ginsenosides Re, Rb1, and Rb2 was significantly decreased (P < 0.05), and rare ginsenosides were detected, with the content of Rh4 and Rg5 reaching 2.65 mg·g-1 and 2.56 mg·g-1. We also explored the preventive effect of fermented ginsenoside extract (FGE) on ALI. Mice were evenly divided into 9 groups as follows: control group, ALI model group, positive drug bifendate group, and treatment group, which included 3 ginsenoside extract (GE) groups and 3 FGE groups (dosage of 150, 300, and 450 mg·kg-1 b.w.). The results showed that compared with the ALI model group, FGE significantly increased the levels of glutathione peroxidase, hydroperoxidase, and superoxide dismutase and also decreased the malondialdehyde level. The levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin markers were significantly reduced, and the levels of inflammatory cytokines TNF-α, IL-6, and IL-1β were significantly decreased. Bioinformatics analysis combined with Western blot validation explored the molecular mechanism of the effect of FGE. It was found that FGE could downregulate the expression of the p-AKT/AKT and the p-mTOR/mTOR ratios. These results suggested that FGE played an alleviative role in ALI by promoting autophagy to inhibit the AKT/mTOR signaling pathway.

Antihypertensive drug-associated adverse events in osteoarthritis: a study of a large real-world sample based on the FAERS database

Background

Hypertension is a common complication in patients with osteoarthritis (OA). There is increasing interest in the relationship between hypertension and OA. However, hypertension has been reported to negatively affect symptoms and quality of life in patients with OA. Therefore, treating hypertension is crucial for patients with OA. However, there is a lack of real-world studies on the effects of medications for treating hypertension on OA.

Methods

Data from the FAERS database from January 2004 to December 2023 were extracted for disproportionality analyses, and proportional reporting ratios (PRRs) were used to assess the association between medications for hypertension and all types of arthritis. Adverse event signals were identified and determined using reporting odds ratios (RORs) Adverse event signals were considered to have occurred if a drug-induced adverse event was recorded more than or equal to 3 and the lower limit of the ROR confidence interval was more than 1. We selected five classes of drugs including, calcium channel blockers (CCBs), angiotensin converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), thiazide diuretics and β-blockers and representative drugs were analysed for osteoarthritis-related adverse reactions, and age and gender subgroups were analysed for drugs of significance. We also analysed the occurrence of AEs in relation to time using the Weibull distribution.

Results

In terms of overall data, we found significant OA adverse reaction signals only for ARBs among the five drug classes.ARB AEs for spinal osteoarthritis (ROR 4.64, 95% CI 3.62-5.94), osteoarthritis (ROR 3.24 95% CI 2.82-3.72) and gouty arthritis (ROR 3.27 95% CI 1.22-8.75) were the three adverse reactions with the loudest signals. Next, we found that valsartan had strong osteoarthritis adverse reaction signals among the three ARBs, namely, irbesartan, cloxartan, and valsartan. We also analysed age and gender subgroups and found that osteoarthritis signals were strongest in the 18-65 and 65+ population, while females seem to be more prone to valsartan-related OA AEs.

Conclusion

ARBs, especially valsartan, have significant positive signals for OA AEs. Therefore, ARB drugs, especially valsartan, should be used with caution when treating patients with OA combined with hypertension.

Isoquercetin Ameliorates Osteoarthritis via Nrf2/NF-κB Axis: An In Vitro and In Vivo Study

Osteoarthritis (OA) is a progressive joint disease characterized by extracellular matrix (ECM) degradation and inflammation, which is involved with pathological microenvironmental alterations induced by damaged chondrocytes. However, current therapies are not effective in alleviating the progression of OA. Isoquercetin is a natural flavonoid glycoside compound that has various pharmacological effects including anticancer, anti-diabetes and blood lipid regulation. Previous evidence suggests that isoquercetin has anti-inflammatory properties in various diseases, but its effect on OA has not been investigated yet. In this study, through western bolt, qRT-PCR and ELISA, it was found that isoquercetin could reduce the increase of ADAMTS5, MMP13, COX-2, iNOS and IL-6 induced by IL-1β, suggesting that isoquercetin could inhibit the inflammation and ECM degradation of chondrocytes. Through nuclear-plasma separation technique, western blot and immunocytochemistry, it can be found that Nrf2 and NF-κB pathways are activated in this process, and isoquercetin may rely on this process to play its protective role. In vivo, the results of X-ray and SO staining show that intra-articular injection of isoquercetin reduces the degradation of cartilage in the mouse OA model. In conclusion, the present work suggests that isoquercetin may benefit chondrocytes by regulating the Nrf2/NF-κB signaling axis, which supports isoquercetin as a potential drug for the treatment of OA.

Regulation of bone homeostasis: signaling pathways and therapeutic targets

As a highly dynamic tissue, bone is continuously rebuilt throughout life. Both bone formation by osteoblasts and bone resorption by osteoclasts constitute bone reconstruction homeostasis. The equilibrium of bone homeostasis is governed by many complicated signaling pathways that weave together to form an intricate network. These pathways coordinate the meticulous processes of bone formation and resorption, ensuring the structural integrity and dynamic vitality of the skeletal system. Dysregulation of the bone homeostatic regulatory signaling network contributes to the development and progression of many skeletal diseases. Significantly, imbalanced bone homeostasis further disrupts the signaling network and triggers a cascade reaction that exacerbates disease progression and engenders a deleterious cycle. Here, we summarize the influence of signaling pathways on bone homeostasis, elucidating the interplay and crosstalk among them. Additionally, we review the mechanisms underpinning bone homeostatic imbalances across diverse disease landscapes, highlighting current and prospective therapeutic targets and clinical drugs. We hope that this review will contribute to a holistic understanding of the signaling pathways and molecular mechanisms sustaining bone homeostasis, which are promising to contribute to further research on bone homeostasis and shed light on the development of targeted drugs.

CircRELL1 promotes osteoarthritis progression by regulating miR-200c-3p

Background

There is a growing body of evidence indicating a potential association between circular RNA and the pathogenesis of human osteoarthritis (OA). Nevertheless, the precise extent of their involvement in OA remains largely unexplored. Hence, the objective of this investigation is to elucidate the function of Circular (Circ) RELL1 in the context of OA.

Methods

24 OA tissue samples and 11 normal tissue samples were collected. The inflammatory OA-like conditions were established by Destabilized Medial Meniscus (DMM) operation in mice and LPS-induced C28/I2 cells. OA severity and articular cartilage degradation were assessed by Safranin-O staining, hematoxylin-eosin (H&E) staining, and International Society for Osteoarthritis Research (OARSI) criteria. CircRELL1, miR-200c-3p, and TCF4 were measured by RT-qPCR and Immunoblot. The cell viability and apoptosis rate were measured by MTT and flow cytometry, respectively. The levels of cytokines interleukin (IL)-1β, IL-6, and TNF-α were determined by ELISA. Apoptosis-associated proteins (cleaved caspase-3, Bax, and Bcl-2) and extracellular matrix (ECM) degradation-associated proteins (MMP13, collagen II, and Aggrecan) were detected by Immunoblot. The interaction between miR-200c-3p and circRELL1 or TCF4 was verified by dual luciferase reporter assay and RIP assay.

Results

CircRELL1 expression was upregulated in OA patients, and the results were consistent in DMM mice and LPS-treated C28/I2 cells. Silencing circRELL1 improved cartilage injury caused by DMM and contributed to a lower OARSI score. Silencing CircRELL1 increased the activity of OA chondrocytes in vivo and in vitro and inhibited cellular inflammatory responses and ECM degradation. In terms of mechanism, circRELL1 functioned by targeting miR-200c-3p, leading to the suppression of inflammatory factor production, cell apoptosis, and ECM degradation, thus inhibiting the progression of OA.

Conclusion

CircRELL1 may promote the progression of OA by regulating the miR-200c-3p.

Characterizing mitochondrial features in osteoarthritis through integrative multi-omics and machine learning analysis

Purpose

Osteoarthritis (OA) stands as the most prevalent joint disorder. Mitochondrial dysfunction has been linked to the pathogenesis of OA. The main goal of this study is to uncover the pivotal role of mitochondria in the mechanisms driving OA development.

Materials and methods

We acquired seven bulk RNA-seq datasets from the Gene Expression Omnibus (GEO) database and examined the expression levels of differentially expressed genes related to mitochondria in OA. We utilized single-sample gene set enrichment analysis (ssGSEA), gene set enrichment analysis (GSEA), and weighted gene co-expression network analysis (WGCNA) analyses to explore the functional mechanisms associated with these genes. Seven machine learning algorithms were utilized to identify hub mitochondria-related genes and develop a predictive model. Further analyses included pathway enrichment, immune infiltration, gene-disease relationships, and mRNA-miRNA network construction based on these hub mitochondria-related genes. genome-wide association studies (GWAS) analysis was performed using the Gene Atlas database. GSEA, gene set variation analysis (GSVA), protein pathway analysis, and WGCNA were employed to investigate relevant pathways in subtypes. The Harmonizome database was employed to analyze the expression of hub mitochondria-related genes across various human tissues. Single-cell data analysis was conducted to examine patterns of gene expression distribution and pseudo-temporal changes. Additionally, The real-time polymerase chain reaction (RT-PCR) was used to validate the expression of these hub mitochondria-related genes.

Results

In OA, the mitochondria-related pathway was significantly activated. Nine hub mitochondria-related genes (SIRT4, DNAJC15, NFS1, FKBP8, SLC25A37, CARS2, MTHFD2, ETFDH, and PDK4) were identified. They constructed predictive models with good ability to predict OA. These genes are primarily associated with macrophages. Unsupervised consensus clustering identified two mitochondria-associated isoforms that are primarily associated with metabolism. Single-cell analysis showed that they were all expressed in single cells and varied with cell differentiation. RT-PCR showed that they were all significantly expressed in OA.

Conclusion

SIRT4, DNAJC15, NFS1, FKBP8, SLC25A37, CARS2, MTHFD2, ETFDH, and PDK4 are potential mitochondrial target genes for studying OA. The classification of mitochondria-associated isoforms could help to personalize treatment for OA patients.

Targeting the senescence-related genes MAPK12 and FOS to alleviate osteoarthritis

Background

The mechanism by which chondrocyte senescence aggravate OA progression has not yet been well elucidated. The aim of this study was to investigate the chondrocyte senescence related gene biosignatures in OA, and to analyze on the underlying mechanisms of senescence in OA.

Materials and methods

We intersected osteoarthritis dataset GSE82107 from GEO database and senescence dataset from CellAge database of human senescence-associated genes based on genetic manipulations experiments plus gene expression profilin, and screened out 4 overlapping genes. The hub genes were verified in vitro and in human OA cartilage tissues by qRT-PCR. We further confirmed the function of mitogen-activated protein kinase 12 (MAPK12) and Fos proto-oncogene (FOS) in OA in vitro and in vivo by qRT-PCR, western blotting, Edu staining, immunofluorescence, SA-β-gal staining, HE, IHC, von frey test, and hot plate.

Results

1458 downregulated and 218 upregulated DEGs were determined from GSE82107, and 279 human senescence-associated genes were downloaded from CellAge database. After intersection assay, we screened out 4 overlapping genes, of which FOS, CYR61 and TNFSF15 were upregulated, MAPK12 was downregulated. The expression of MAPK12 was obviously downregulated, whereas the expression profiles of FOS, CYR61 and TNFSF15 were remarkedly upregulated in H2O2- or IL-1β-stimulated C28/I2 cells, human OA cartilage tissues, and knee cartilage of aging mice. Furthermore, both MAPK12 over-expression and FOS knock-down can promote cell proliferation and cartilage anabolism, inhibit cell senescence and cartilage catabolism, relieve joint pain in H2O2- or IL-1β-stimulated C28/I2 cells and mouse primary chondrocytes, destabilization of the medial meniscus (DMM) mice.

Conclusion

This study explored that MAPK12 and FOS are involved in the occurrence and development of OA through modulating chondrocyte senescence. They might be biomarkers of OA chondrocyte senescence, and provides some evidence as subsequent possible therapeutic targets for OA.

The translational potential of this article

The translation potential of this article is that we revealed MAPK12 and FOS can effectively alleviate OA by regulating chondrocyte senescence, and thus provided potential therapeutic targets for prevention or treatment of OA in the future.

IL16 Regulates Osteoarthritis Progression as a Target Gene of Novel-miR-81

OBJECTIVE

Functional polymorphisms of interleukin 16 (IL16) have been reported to be closely related to the risk of osteoarthritis (OA). However, how IL16 affects OA remains unclear. In this study, the role of IL16 in OA and the possible mechanisms were examined.

METHODS

We established a meniscal/ligament injury (MLI) post-traumatic OA model in Sprague Dawley rats and an IL1β-induced ADTC5 cells OA model. We detected the expression of IL16, novel-miR-81, MMP3, and MMP13 by quantitative real-time polymerase chain reaction. Western blot was performed to detect the expression of IL16, MMP3, and MMP13. The association between IL16 and novel-miR-81 was confirmed by luciferase reporter assay. Hematoxylin and eosin staining, Safranin O and Fast Green staining, and immunohistochemical staining were performed to clarify the effect of intra-articular injection of novel-miR-81 agomir in rats OA model.

RESULTS

IL16 was upregulated in OA model. Knockdown of IL16 and overexpression of novel-miR-81 downregulated the expression of MMP3 and MMP13. Importantly, IL16 was a key target of novel-miR-81. Intra-articular injection of novel-miR-81 agomir could attenuate OA progression in rats OA model.

CONCLUSION

Novel-miR-81 targeted IL16 to relieve OA, suggesting that novel-miR-81and IL16 may be new therapeutic targets for OA.

Adipocyte enhancer binding protein 1 knockdown alleviates osteoarthritis through inhibiting NF-κB signaling pathway-mediated inflammation and extracellular matrix degradation

Inflammation promotes the degradation of the extracellular matrix, which contributes to the development of osteoarthritis (OA). Adipocyte enhancer binding protein 1 (AEBP1) participates in multiple pathological processes related to inflammatory diseases. However, the role of AEBP1 in OA development is unknown. We found a higher AEBP1 expression in articular cartilage of OA patients (n = 20) compared to their normal controls (n = 10). Thus, we inferred that AEBP1 might affect OA progression. Then mice with destabilization of the medial meniscus (DMM) surgery and chondrocytes with IL-1β treatment (10 ng/mL) were used to mimic OA. The increased AEBP1 expression was observed in models of OA. AEBP1 knockdown in chondrocytes reversed IL-1β-induced inflammation and extracellular matrix degradation, which was mediated by the inactivation of NF-κB signaling pathway and the increased IκBα activity. Co-immunoprecipitation assay indicated the interaction between AEBP1 and IκBα. Importantly, IκBα knockdown depleted the protective role of AEBP1 knockdown in OA. Moreover, AEBP1 knockdown in mice with OA showed similar results to those in chondrocytes. Collectively, our findings suggest that AEBP1 knockdown alleviates the development of OA, providing a novel strategy for OA treatment.

Elevated microRNA-214-3p level ameliorates neuroinflammation after spinal cord ischemia-reperfusion injury by inhibiting Nmb/Cav3.2 pathway

BACKGROUND

Neuromedin B (Nmb) plays a pivotal role in the transmission of neuroinflammation, particularly during spinal cord ischemia-reperfusion injury (SCII). However, the detailed molecular mechanisms underlying this process remain elusive.

METHODS

The SCII model was established by clamping the abdominal aorta of male Sprague-Dawley (SD) rats for 60 min. The protein expression levels of Nmb, Cav3.2, and IL-1β were detected by Western blotting, while miR-214-3p expression was quantified by qRT-PCR. The targeted regulation between miR-214-3p and Nmb was investigated using a dual-luciferase reporter gene assay. The cellular localization of Nmb and Cav3.2 with cell-specific markers was visualized by immunofluorescence staining. The specific roles of miR-214-3p on the Nmb/Cav3.2 interactions in SCII-injured rats were explored by intrathecal injection of Cav3.2-siRNA, PD168368 (a specific NmbR inhibitor) and synthetic miR-214-3p agomir and antagomir in separate experiments. Additionally, hind-limb motor function was evaluated using the modified Tarlov scores.

RESULTS

Compared to the Sham group, the protein expression levels of Nmb, Cav3.2, and the proinflammatory factor Interleukin(IL)-1β were significantly elevated at 24 h post-SCII. Intrathecal injection of PD168368 and Cav3.2-siRNA significantly suppressed the expression of Cav3.2 and IL-1β compared to the SCII group. The miRDB database and dual-luciferase reporter gene assay identified Nmb as a direct target of miR-214-3p. As expected, in vivo overexpression of miR-214-3p by agomir-214-3p pretreatment significantly inhibited the increases in Nmb, Cav3.2 and IL-1β expression and improved lower limb motor function in SCII-injured rats, while antagomiR-214-3p pretreatment reversed these effects.

CONCLUSIONS

Nmb protein levels positively correlated with Cav3.2 expression in SCII rats. Upregulating miR-214-3p ameliorated hind-limb motor function and protected against neuroinflammation via inhibiting the aberrant Nmb/Cav3.2 interactions and downstream IL-1β release. These findings provide novel therapeutic targets for clinical prevention and treatment of SCII.

Electro-acupuncture modulated miR-214 expression to prevent chondrocyte apoptosis and reduce pain by targeting BAX and TRPV4 in osteoarthritis rats

Osteoarthritis (OA) is a highly prevalent joint disorder characterized by progressive degeneration of articular cartilage, subchondral bone remodeling, osteophyte formation, synovial inflammation, and meniscal damage. Although the etiology of OA is multifactorial, pro-inflammatory processes appear to play a key role in disease pathogenesis. Previous studies indicate that electroacupuncture (EA) exerts chondroprotective, anti-inflammatory, and analgesic effects in preclinical models of OA, but the mechanisms underlying these potential therapeutic benefits remain incompletely defined. This study aimed to investigate the effects of EA on OA development in a rat model, as well as to explore associated molecular mechanisms modulated by EA treatment. Forty rats were divided into OA, EA, antagomiR-214, and control groups. Following intra-articular injection of monosodium iodoacetate to induce OA, EA and antagomiR-214 groups received daily EA stimulation at acupoints around the knee joint for 21 days. Functional pain behaviors and chondrocyte apoptosis were assessed as outcome measures. The expression of microRNA-214 (miR-214) and its downstream targets involved in apoptosis and nociception, BAX and TRPV4, were examined. Results demonstrated that EA treatment upregulated miR-214 expression in OA knee cartilage. By suppressing pro-apoptotic BAX and pro-nociceptive TRPV4, this EA-induced miR-214 upregulation ameliorated articular pain and prevented chondrocyte apoptosis. These findings suggested that miR-214 plays a key role mediating EA's therapeutic effects in OA pathophysiology, and represents a promising OA treatment target for modulation by acupuncture.

Emerging technology has a brilliant future: the CRISPR-Cas system for senescence, inflammation, and cartilage repair in osteoarthritis

Osteoarthritis (OA), known as one of the most common types of aseptic inflammation of the musculoskeletal system, is characterized by chronic pain and whole-joint lesions. With cellular and molecular changes including senescence, inflammatory alterations, and subsequent cartilage defects, OA eventually leads to a series of adverse outcomes such as pain and disability. CRISPR-Cas-related technology has been proposed and explored as a gene therapy, offering potential gene-editing tools that are in the spotlight. Considering the genetic and multigene regulatory mechanisms of OA, we systematically review current studies on CRISPR-Cas technology for improving OA in terms of senescence, inflammation, and cartilage damage and summarize various strategies for delivering CRISPR products, hoping to provide a new perspective for the treatment of OA by taking advantage of CRISPR technology.

Sipeimine ameliorates osteoarthritis progression by suppression of NLRP3 inflammasome-mediated pyroptosis through inhibition of PI3K/AKT/NF-κB pathway: An in vitro and in vivo study

Background

Osteoarthritis (OA) is a chronic and degenerative condition that persists and progresses over time. Sipeimine (Sip), a steroidal alkaloid derived from Fritillariae Cirrhosae Bulbus, has attracted considerable attention due to its exceptional anti-inflammatory, analgesic, antioxidant, and anti-cancer characteristics. However, Sip's effects on OA and its mechanism still need further research.

Methods

This study utilized network pharmacology to identify initial targets for Sip. Functional associations of Sip in OA were clarified through Gene Ontology (GO) enrichment analysis, bioinformatically analyzing a list of targets. Subsequently, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis assessed pathways linked to Sip's therapeutic efficacy in OA. Molecular docking techniques explored Sip's binding affinity with key targets. In vitro experiments assessed Sip's impact on lipopolysaccharide (LPS)-induced pro-inflammatory factors and its protective effects on collagen-II and aggrecan degradation within the extracellular matrix (ECM). Western blotting and fluorescence analyses were conducted to determine Sip-mediated signaling pathways. Moreover, in vivo experiments using a mouse OA model validated Sip's therapeutic efficacy.

Results

The results from network pharmacology revealed a total of 57 candidate targets for Sip in OA treatment. GO enrichment analysis demonstrated a robust correlation between Sip and inflammatory response, response to LPS and NF-κB-inducing kinase activity in OA. KEGG enrichment analysis highlighted the significance of NF-κB and PI3K-AKT pathways in Sip's therapeutic potential for OA. Furthermore, molecular docking results demonstrated Sip's robust binding affinity with p65 and PI3K. In vitro experiments demonstrated Sip's effectively suppressed the expression of pro-inflammatory factors induced by LPS, such as COX-2, iNOS, IL-1β, and IL-18. Besides, Sip counteracted the degradation of collagen-II and aggrecan within the ECM and the expression of MMP-13 and ADAMTS-5 mediated by LPS. The safeguarding effects of Sip were ascribed to its inhibition of PI3K/AKT/NF-κB pathway and NLRP3 inflammasome mediated pyroptosis. Additionally, in vivo experiments revealed that Sip could alleviate the subchondral remodeling, cartilage degeneration, synovitis as well as ECM degradation a mouse model of OA.

Conclusion

Sip exhibited potential in attenuating OA progression by suppressing the PI3K/AKT/NF-κB pathway, consequently inhibiting the activation of NLRP3 inflammasome and pyroptosis.

The translational potential statement

The translational potential of this articleThis study provides a biological rationale for the use of Sip as a potential candidate for OA treatment, provide a new concept for the cartilage targeted application of natural compounds.

Knocking-down long non-coding RNA LINC01094 prohibits chondrocyte apoptosis via regulating microRNA-577/metal-regulatory transcription factor 1 axis

PURPOSE

The abnormal function and survival of chondrocytes result in articular cartilage failure, which may accelerate the onset and development of osteoarthritis (OA). This study is aimed to investigate the role of LINC01094 in chondrocyte apoptosis.

METHODS

The viability and apoptosis of lipopolysaccharide (LPS)-induced chondrocytes were evaluated through CCK-8 assay and flow cytometry analysis, respectively. The expression levels of LINC01094, miR-577 and MTF1 were detected by qRT-PCR. Dual luciferase reporter tests were implemented for the verification of targeted relationships among them. Western blotting was employed to measure the levels of pro-apoptotic proteins (Caspase3 and Caspase9).

RESULTS

The viability of LPS-induced chondrocytes was overtly promoted by loss of LINC01094 or miR-577 upregulation, but could be repressed via MTF1 overexpression. The opposite results were observed in apoptosis rate and the levels of Caspase3 and Caspase9. LINC01094 directly bound to miR-577, while MTF1 was verified to be modulated by miR-577. Both LINC01094 and MTF1 were at high levels, whereas miR-577 was at low level in OA synovial fluid and LPS-induced chondrocytes. Furthermore, the highly expressed miR-577 abolished the influences of MTF1 overexpression on LPS-induced chondrocytes.

CONCLUSIONS

Silencing of LINC01094 represses the apoptosis of chondrocytes through upregulating miR-577 expression and downregulating MTF1 levels, providing a preliminary insight for the treatment of OA in the future.

Osteoporosis GWAS-implicated DNM3 locus contextually regulates osteoblastic and chondrogenic fate of mesenchymal stem/progenitor cells through oscillating miR-199a-5p levels

Genome wide association study (GWAS)-implicated bone mineral density (BMD) signals have been shown to localize in cis-regulatory regions of distal effector genes using 3D genomic methods. Detailed characterization of such genes can reveal novel causal genes for BMD determination. Here, we elected to characterize the "DNM3" locus on chr1q24, where the long non-coding RNA DNM3OS and the embedded microRNA MIR199A2 (miR-199a-5p) are implicated as effector genes contacted by the region harboring variation in linkage disequilibrium with BMD-associated sentinel single nucleotide polymorphism, rs12041600. During osteoblast differentiation of human mesenchymal stem/progenitor cells (hMSC), miR-199a-5p expression was temporally decreased and correlated with the induction of osteoblastic transcription factors RUNX2 and Osterix. Functional relevance of miR-199a-5p downregulation in osteoblastogenesis was investigated by introducing miR-199a-5p mimic into hMSC. Cells overexpressing miR-199a-5p depicted a cobblestone-like morphological change and failed to produce BMP2-dependent extracellular matrix mineralization. Mechanistically, a miR-199a-5p mimic modified hMSC propagated normal SMAD1/5/9 signaling and expressed osteoblastic transcription factors RUNX2 and Osterix but depicted pronounced upregulation of SOX9 and enhanced expression of essential chondrogenic genes ACAN, COMP, and COL10A1. Mineralization defects, morphological changes, and enhanced chondrogenic gene expression associated with miR-199a-5p mimic over-expression were restored with miR-199a-5p inhibitor suggesting specificity of miR-199a-5p in chondrogenic fate specification. The expression of both the DNM3OS and miR-199a-5p temporally increased and correlated with hMSC chondrogenic differentiation. Although miR-199a-5p overexpression failed to further enhance chondrogenesis, blocking miR-199a-5p activity significantly reduced chondrogenic pellet size, extracellular matrix deposition, and chondrogenic gene expression. Taken together, our results indicate that oscillating miR-199a-5p levels dictate hMSC osteoblast or chondrocyte terminal fate. Our study highlights a functional role of miR-199a-5p as a BMD effector gene at the DNM3 BMD GWAS locus, where patients with cis-regulatory genetic variation which increases miR-199a-5p expression could lead to reduced osteoblast activity.

LncRNA MALAT1 promotes osteogenic differentiation through the miR-93-5p/SMAD5 axis

OBJECTIVES

Promoting the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) is a way to regenerate periodontal bone. This study aimed to determine whether lncRNA MALAT1 promotes the osteogenic differentiation of human PDLSCs in vitro.

MATERIALS AND METHODS

Human PDLSCs were extracted from the human periodontal ligament, and after osteogenic differentiation was induced using osteogenic medium, the human PDLSCs were transfected with siRNA-MALAT1, miR-93-5p mimics, and miR-93-5p inhibitors. The expression of osteogenesis-related genes was assessed by RT-qPCR and western blotting, alkaline phosphatase (ALP) activity was assessed by ALP activity assay, and the formation of mineralized nodules was assessed by alizarin red S (ARS) staining. RNA immunoprecipitation (RIP) and luciferase assays were performed to assess the binding of MALAT1, miR-93-5p, and SMAD5.

RESULTS

The expression of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was upregulated, while that of miR-93-5p was downregulated after PDLSC osteogenic differentiation. Knockdown of MALAT1 inhibited the osteogenic differentiation of PDLSCs, and MALAT1 expression negatively correlated with miR-93-5p expression. miR-93-5p inhibited the osteogenic differentiation of human PDLSCs by specifically binding to SMAD5.

CONCLUSION

MALAT1 regulates human PDLSC differentiation by regulating the miR-93-5p/SMAD5 axis.

Suppression of long noncoding RNA SNHG6 alleviates cigarette smoke-induced lung inflammation by modulating NF-κB signaling

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a widespread inflammatory disease with a high mortality rate. Long noncoding RNAs play important roles in pulmonary diseases and are potential targets for inflammation intervention.

METHODS

The expression of small nucleolar RNA host gene 6 (SNHG6) in mouse lung epithelial cell line MLE12 with or without cigarette smoke extract (CSE) treatment was first detected using quantitative reverse-transcription PCR. ELISA was used to evaluate the release of inflammatory cytokines (TNF-α, IL-1β, and IL-6). The binding site of miR-182-5p with SNHG6 was predicted by using miRanda, which was verified by double luciferase reporter assay.

RESULTS

Here, we revealed that SNHG6 was upregulated in CS-exposed MLE12 alveolar epithelial cells and lungs from COPD-model mice. SNHG6 silencing weakened CS-induced inflammation in MLE12 cells and mouse lungs. Mechanistic investigations revealed that SNHG6 could upregulate IκBα kinase through sponging the microRNA miR-182-5p, followed by activated NF-κB signaling. The suppressive effects of SNHG6 silencing on CS-induced inflammation were blocked by an miR-182-5p inhibitor.

CONCLUSION

Overall, our findings suggested that SNHG6 regulates CS-induced inflammation in COPD by activating NF-κB signaling, thereby offering a novel potential target for COPD treatment.

Phytochemicals against Osteoarthritis by Inhibiting Apoptosis

Osteoarthritis (OA) is a chronic joint disease that causes pathological changes in articular cartilage, synovial membrane, or subchondral bone. Conventional treatments for OA include surgical and non-surgical methods. Surgical treatment is suitable for patients in the terminal stage of OA. It is often the last choice because of the associated risks and high cost. Medication of OA mainly includes non-steroidal anti-inflammatory drugs, analgesics, hyaluronic acid, and cortico-steroid anti-inflammatory drugs. However, these drugs often have severe side effects and cannot meet the needs of patients. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Apoptosis is programmed cell death, which is a kind of physiologic cell suicide determined by heredity and conserved by evolution. Inhibition of apoptosis-related pathways has been found to prevent and treat a variety of diseases. Excessive apoptosis can destroy cartilage homeostasis and aggravate the pathological process of OA. Therefore, inhibition of apoptosis-related factors or signaling pathways has become an effective means to treat OA. Phytochemicals are active ingredients from plants, and it has been found that phytochemicals can play an important role in the prevention and treatment of OA by inhibiting apoptosis. We summarize preclinical and clinical studies of phytochemicals for the treatment of OA by inhibiting apoptosis. The results show that phytochemicals can treat OA by targeting apoptosis-related pathways. On the basis of improving some phytochemicals with low bioavailability, poor water solubility, and high toxicity by nanotechnology-based drug delivery systems, and at the same time undergoing strict clinical and pharmacological tests, phytochemicals can be used as a potential therapeutic drug for OA and may be applied in clinical settings.

WITHDRAWN: The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

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[miR-515-5p targeting Toll-like receptor 4 regulates myeloid differentiation primary response gene 88/nuclear factor-kappa B pathway to inhibit apoptosis and inflammatory response of osteoarthritis chondrocytes]

Objective

To explore the molecular mechanism of miR-515-5p in inhibiting chondrocyte apoptosis and alleviating inflammatory response in osteoarthritis (OA).

Methods

Human cartilage cell line C28/I2 was cultured in vitro and treated with 10 ng/mL interleukin 1β (IL-1β) for 24 hours to construct an in vitro OA model. C28/I2 cells were transfected with miR mimics, mimics negative control (NC), over expression (oe)-NC, and oe-Toll-like receptor 4 (TLR4), respectively, and then treated with 10 ng/mL IL-1β for 24 hours to establish OA model. Cell proliferation capacity was detected by cell counting kit 8 and 5-Ethynyl-2'-deoxyuridine, cell apoptosis and cell cycle were detected by flow cytometry, and B-cell lymphoma 2 protion (Bcl-2), Bcl-2-associated X protein (Bax), cleaved-Caspase-3, TLR4, myeloid differentiation primary response gene 88 (MyD88), p65 and phosphorylated p65 (p-p65) protein expression levels were detected by Western blot. Real-time fluorescence quantitative PCR was used to detect mRNA expression levels of miR-515-5p and TLR4, and ELISA was used to detect pro-inflammatory factor prostaglandin E2 (PGE2), tumor necrosis factor α (TNF -α), and IL-6 levels in cell supernatant. The potential binding sites between miR-515-5p and TLR4 were predicted by BiBiServ2 database, and the targeting relationship between miR-515-5p and TLR4 was verified by dual luciferase reporting assay.

Results

After the treatment of C28/I2 cells with IL-1β, the expressions of miR-515-5p and Bcl-2 protein and the proliferation ability of C28/I2 cells significantly reduced. The expression levels of Bax and cleaved-Caspase-3 protein, the levels of pro-inflammatory factors (PGE2, TNF-α, IL-6) in the supernatant of C28/I2 cells, and the apoptosis of C28/I2 cells significantly increased. In addition, the proportion of the cells at S phase and G 2 phase decreased significantly, and the proportion of cells at G 1 phase increased significantly, suggesting that the cell cycle was blocked after IL-1β treatment. After transfection with miR mimics, the expression level of miR-515-5p in the cells significantly up-regulated, partially reversing the apoptosis of OA chondrocytes induced by IL-1β, and alleviating the cycle arrest and inflammatory response of OA chondrocytes. After treating C28/I2 cells with IL-1β, the mRNA and protein levels of TLR4 significantly increased. Overexpression of miR-515-5p targeted inhibition of TLR4 expression and blocked activation of MyD88/nuclear factor κB (NF-κB) pathway. Overexpression of TLR4 could partially reverse the effect of miR mimics on IL-1β-induced apoptosis and inflammation of OA chondrocytes.

Conclusion

miR-515-5p negatively regulates the expression of TLR4, inhibits the activation of MyD88/NF-κB pathway and apoptosis of OA chondrocytes, and effectively alleviates the inflammatory response of the cells.

The emerging role of noncoding RNAs in the PI3K/AKT/mTOR signalling pathway in breast cancer

Breast cancer persists as a major problem for the world's healthcare, thus it is essential to fully understand the complex molecular processes that cause its growth and development. ncRNAs had been discovered to serve critical roles in a variety of cellular functions, including the regulation of signalling pathways. Within different pathways, the AKT/PI3K/mTOR signalling cascade has received a lot of interest because of its role in cancer. A complex interaction between ncRNAs, notably miRNAs, lncRNAs, and circRNAs, and the AKT/PI3K/mTOR signalling pathway exerts both oncogenic and tumor-suppressive activities by targeting critical components of the pathway directly or indirectly. Through miRNA-mediated post-transcriptional regulation, lncRNA-guided chromatin remodelling, and circRNA sequestration, ncRNAs modulate the activity of PI3K, AKT, and mTOR, influencing cell proliferation, survival, and metastasis. Furthermore, ncRNAs can serve as promising biomarkers for breast cancer prognosis, diagnosis, and treatment response, as their dysregulation is commonly observed in breast cancer patients. Harnessing the potential of ncRNAs as therapeutic targets or tools for restoring pathway homeostasis holds promise for innovative treatment strategies in breast cancer. Understanding the intricate regulatory networks orchestrated by ncRNAs in this context may pave the way for novel diagnostic approaches, therapeutic interventions, and a deeper comprehension of breast cancer's molecular landscape, ultimately improving patient outcomes. This abstract underscores the emerging significance of ncRNAs in the AKT/PI3K/mTOR signaling pathway in breast cancer.

Current therapies for osteoarthritis and prospects of CRISPR-based genome, epigenome, and RNA editing in osteoarthritis treatment

Osteoarthritis (OA) is one of the most common degenerative joint diseases worldwide, causing pain, disability, and decreased quality of life. The balance between regeneration and inflammation-induced degradation results in multiple etiologies and complex pathogenesis of OA. Currently, there is a lack of effective therapeutic strategies for OA treatment. With the development of CRISPR-based genome, epigenome, and RNA editing tools, OA treatment has been improved by targeting genetic risk factors, activating chondrogenic elements, and modulating inflammatory regulators. Supported by cell therapy and in vivo delivery vectors, genome, epigenome, and RNA editing tools may provide a promising approach for personalized OA therapy. This review summarizes CRISPR-based genome, epigenome, and RNA editing tools that can be applied to the treatment of OA and provides insights into the development of CRISPR-based therapeutics for OA treatment. Moreover, in-depth evaluations of the efficacy and safety of these tools in human OA treatment are needed.

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

Exosomal Osteoclast-Derived miRNA in Rheumatoid Arthritis: From Their Pathogenesis in Bone Erosion to New Therapeutic Approaches

Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation, pain, and ultimately, bone erosion of the joints. The causes of this disease are multifactorial, including genetic factors, such as the presence of the human leukocyte antigen (HLA)-DRB1*04 variant, alterations in the microbiota, or immune factors including increased cytotoxic T lymphocytes (CTLs), neutrophils, or elevated M1 macrophages which, taken together, produce high levels of pro-inflammatory cytokines. In this review, we focused on the function exerted by osteoclasts on osteoblasts and other osteoclasts by means of the release of exosomal microRNAs (miRNAs). Based on a thorough revision, we classified these molecules into three categories according to their function: osteoclast inhibitors (miR-23a, miR-29b, and miR-214), osteoblast inhibitors (miR-22-3p, miR-26a, miR-27a, miR-29a, miR-125b, and miR-146a), and osteoblast enhancers (miR-20a, miR-34a, miR-96, miR-106a, miR-142, miR-199a, miR-324, and miR-486b). Finally, we analyzed potential therapeutic targets of these exosomal miRNAs, such as the use of antagomiRs, blockmiRs, agomiRs and competitive endogenous RNAs (ceRNAs), which are already being tested in murine and ex vivo models of RA. These strategies might have an important role in reestablishing the regulation of osteoclast and osteoblast differentiation making progress in the development of personalized medicine.

Inhibition of LINC00958 hinders the progression of osteoarthritis through regulation of the miR-214-3p/FOXM1 axis

OBJECTIVE

We investigated the impact of the long noncoding RNA LINC00958 on cellular activity and oxidative stress in osteoarthritis (OA).

METHODS

We performed bioinformatics analysis via StarBase and luciferase reporter assays to predict and validate the interactions between LINC00958 and miR-214-3p and between miR-214-3p and FOXM1. The expression levels of LINC00958, miR-214-3p, and FOXM1 were measured by qRT-PCR and western blotting. To assess effects on CHON-001 cells, we performed MTT proliferation assays, evaluated cytotoxicity with a lactate dehydrogenase (LDH) assay, and examined apoptosis through flow cytometry. Additionally, we measured the levels of apoptosis-related proteins, including BAX and BCL2, using western blotting. The secretion of inflammatory cytokines (IL-6, IL-8, and TNF-α) was measured using ELISA.

RESULTS

Our findings confirmed that LINC00958 is a direct target of miR-214-3p. LINC00958 expression was upregulated but miR-214-3p expression was downregulated in both OA cells and IL-1β-stimulated CHON-001 cells compared to the corresponding control cells. Remarkably, miR-214-3p expression was further reduced after miR-214-3p inhibitor treatment but increased following LINC00958-siRNA stimulation. Silencing LINC00958 significantly decreased its expression, and this effect was reversed by miR-214-3p inhibitor treatment. Notably, LINC00958-siRNA transfection alleviated the IL-1β-induced inflammatory response, as evidenced by the increased cell viability, reduced LDH release, suppression of apoptosis, downregulated BAX expression, and elevated BCL2 levels. Moreover, LINC00958 silencing led to reduced secretion of inflammatory factors from IL-1β-stimulated CHON-001 cells. The opposite results were observed in the miR-214-3p inhibitor-transfected groups. Furthermore, in CHON-001 cells, miR-214-3p directly targeted FOXM1 and negatively regulated its expression.

CONCLUSION

Our findings suggest that downregulating LINC00958 mitigates IL-1β-induced injury in CHON-001 cells through the miR-214-3p/FOXM1 axis. These results imply that LINC00958 plays a role in OA development and may be a valuable therapeutic target for OA.

Biological functions and applications of LncRNAs in the regulation of the extracellular matrix in osteoarthritis

Osteoarthritis (OA) is a major cause of disability, characterized by chronic pain, irreversible destruction, and loss of function of the articular cartilage. The integrity and arrangement of the composition and structure of the extracellular matrix (ECM) are essential for maintaining the elasticity, integrity, and mechanical support function of the cartilage tissue. Osteoarthritis causes substantial changes in the ECM, driving the progression of the disease. Recent studies have shown that the ECM plays a critical role in the development of cartilage tissue as well as the occurrence and development of osteoarthritis by directly or indirectly regulating chondrocyte proliferation, apoptosis, differentiation, and gene expression. Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs derived from large transcripts. Mutations and disorders of lncRNAs are closely related to the development of osteoarthritis. Abnormal expression of lncRNAs in osteoarthritic cartilage regulates the synthesis and decomposition of the cartilaginous ECM. Therefore, the use of lncRNAs as nucleic acid drugs that regulate their targets may reduce ECM degradation, thereby delaying the pathological progression of osteoarthritis. In this review, the regulatory effects of lncRNAs on ECM in different cell behaviors related to OA are summarized. The roles of lncRNAs in the proliferation, apoptosis, differentiation, and ECM-related gene activity of chondrocytes, as well as the application of lncRNAs as potential gene therapy drugs for the repair and regeneration of osteoarthritic tissue, are also reviewed. A better understanding of the roles of lncRNAs in guiding chondrocyte behavior and ECM metabolism is critical for their future applications in osteoarthritis therapy and regenerative medicine.

Overexpression of lncRNA LINC00665 inhibits the proliferation and chondroblast differentiation of bone marrow mesenchymal stem cells by targeting miR-214-3p

BACKGROUND

Osteoarthritis is a chronic disease mainly involving the damage of articular cartilage and the whole articular tissue, which is the main cause of disability in the elderly. To explore more effective treatment measures, this study analyzed the regulatory role and molecular mechanism of lncRNA LINC00665 (LINC00665) in the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), providing a valuable theoretical basis for the pathogenesis and patient treatment of osteoarthritis.

METHODS

Osteoarthritis tissues and healthy tissues were obtained from 52 patients with osteoarthritis and 34 amputated patients without osteoarthritis, and the levels of LINC00665 and miR-214-3p were assessed by RT-qPCR. BMSCs were cultured and induced chondrogenic differentiation. The proliferation ability of BMSCs was detected by CCK-8 method, and the apoptosis level of BMSCs was evaluated by flow cytometry. The content of proteoglycan-glycosaminoglycan (GAG) in cartilage matrix was determined by Alcian blue staining. In addition, the binding relationship between LINC00665 and miR-214-3p was verified by luciferase reporter assay, and the molecular mechanism was further analyzed.

RESULTS

In osteoarthritis tissues, LINC00665 was elevated and miR-214-3p was down-regulated. With the chondrogenic differentiation of BMSCs, the level of GAG increased, and LINC00665 expression gradually decreased, while miR-214-3p level was on the contrary. After transfection of pcDNA3.1-LINC00665 in BMSCs, cell proliferation capacity was decreased, apoptosis rate was increased, and GAG content was reduced. Moreover, LINC00665 sponged miR-214-3p and negatively regulate its expression. Transfection of pcDNA3.1-LINC00665-miR-214-3p mimic changed the regulation of pcDNA3.1-LINC00665 on the viability and chondrogenic differentiation of BMSCs.

CONCLUSIONS

Overexpression of lncRNA LINC00665 inhibited the proliferation and chondrogenic differentiation of BMSCs by targeting miR-214-3p. The LINC00665/miR-214-3p axis may improve joint damage and alleviate the progression of osteoarthritis.